In gcc/: 2011-01-12 Nicola Pero <nicola.pero@meta-innovation.com>

[official-gcc.git] / gcc / dwarf2out.c

/* Output Dwarf2 format symbol table information from GCC.
   Copyright (C) 1992, 1993, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
   2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   Free Software Foundation, Inc.
   Contributed by Gary Funck (gary@intrepid.com).
   Derived from DWARF 1 implementation of Ron Guilmette (rfg@monkeys.com).
   Extensively modified by Jason Merrill (jason@cygnus.com).

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* TODO: Emit .debug_line header even when there are no functions, since
           the file numbers are used by .debug_info.  Alternately, leave
           out locations for types and decls.
         Avoid talking about ctors and op= for PODs.
         Factor out common prologue sequences into multiple CIEs.  */

/* The first part of this file deals with the DWARF 2 frame unwind
   information, which is also used by the GCC efficient exception handling
   mechanism.  The second part, controlled only by an #ifdef
   DWARF2_DEBUGGING_INFO, deals with the other DWARF 2 debugging
   information.  */

/* DWARF2 Abbreviation Glossary:

   CFA = Canonical Frame Address
           a fixed address on the stack which identifies a call frame.
           We define it to be the value of SP just before the call insn.
           The CFA register and offset, which may change during the course
           of the function, are used to calculate its value at runtime.

   CFI = Call Frame Instruction
           an instruction for the DWARF2 abstract machine

   CIE = Common Information Entry
           information describing information common to one or more FDEs

   DIE = Debugging Information Entry

   FDE = Frame Description Entry
           information describing the stack call frame, in particular,
           how to restore registers

   DW_CFA_... = DWARF2 CFA call frame instruction
   DW_TAG_... = DWARF2 DIE tag */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "version.h"
#include "flags.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "regs.h"
#include "insn-config.h"
#include "reload.h"
#include "function.h"
#include "output.h"
#include "expr.h"
#include "libfuncs.h"
#include "except.h"
#include "dwarf2.h"
#include "dwarf2out.h"
#include "dwarf2asm.h"
#include "toplev.h"
#include "ggc.h"
#include "md5.h"
#include "tm_p.h"
#include "diagnostic.h"
#include "tree-pretty-print.h"
#include "debug.h"
#include "target.h"
#include "langhooks.h"
#include "hashtab.h"
#include "cgraph.h"
#include "input.h"
#include "gimple.h"
#include "tree-pass.h"
#include "tree-flow.h"

static void dwarf2out_source_line (unsigned int, const char *, int, bool);
static rtx last_var_location_insn;

#ifdef VMS_DEBUGGING_INFO
int vms_file_stats_name (const char *, long long *, long *, char *, int *);

/* Define this macro to be a nonzero value if the directory specifications
    which are output in the debug info should end with a separator.  */
#define DWARF2_DIR_SHOULD_END_WITH_SEPARATOR 1
/* Define this macro to evaluate to a nonzero value if GCC should refrain
   from generating indirect strings in DWARF2 debug information, for instance
   if your target is stuck with an old version of GDB that is unable to
   process them properly or uses VMS Debug.  */
#define DWARF2_INDIRECT_STRING_SUPPORT_MISSING_ON_TARGET 1
#else
#define DWARF2_DIR_SHOULD_END_WITH_SEPARATOR 0
#define DWARF2_INDIRECT_STRING_SUPPORT_MISSING_ON_TARGET 0
#endif

/* ??? Poison these here until it can be done generically.  They've been
   totally replaced in this file; make sure it stays that way.  */
#undef DWARF2_UNWIND_INFO
#undef DWARF2_FRAME_INFO
#if (GCC_VERSION >= 3000)
 #pragma GCC poison DWARF2_UNWIND_INFO DWARF2_FRAME_INFO
#endif

#ifndef INCOMING_RETURN_ADDR_RTX
#define INCOMING_RETURN_ADDR_RTX  (gcc_unreachable (), NULL_RTX)
#endif

/* Map register numbers held in the call frame info that gcc has
   collected using DWARF_FRAME_REGNUM to those that should be output in
   .debug_frame and .eh_frame.  */
#ifndef DWARF2_FRAME_REG_OUT
#define DWARF2_FRAME_REG_OUT(REGNO, FOR_EH) (REGNO)
#endif

/* Save the result of dwarf2out_do_frame across PCH.  */
static GTY(()) bool saved_do_cfi_asm = 0;

/* Decide whether we want to emit frame unwind information for the current
   translation unit.  */

int
dwarf2out_do_frame (void)
{
  /* We want to emit correct CFA location expressions or lists, so we
     have to return true if we're going to output debug info, even if
     we're not going to output frame or unwind info.  */
  if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
    return true;

  if (saved_do_cfi_asm)
    return true;

  if (targetm.debug_unwind_info () == UI_DWARF2)
    return true;

  if ((flag_unwind_tables || flag_exceptions)
      && targetm.except_unwind_info (&global_options) == UI_DWARF2)
    return true;

  return false;
}

/* Decide whether to emit frame unwind via assembler directives.  */

int
dwarf2out_do_cfi_asm (void)
{
  int enc;

#ifdef MIPS_DEBUGGING_INFO
  return false;
#endif
  if (saved_do_cfi_asm)
    return true;
  if (!flag_dwarf2_cfi_asm || !dwarf2out_do_frame ())
    return false;
  if (!HAVE_GAS_CFI_PERSONALITY_DIRECTIVE)
    return false;

  /* Make sure the personality encoding is one the assembler can support.
     In particular, aligned addresses can't be handled.  */
  enc = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/2,/*global=*/1);
  if ((enc & 0x70) != 0 && (enc & 0x70) != DW_EH_PE_pcrel)
    return false;
  enc = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0,/*global=*/0);
  if ((enc & 0x70) != 0 && (enc & 0x70) != DW_EH_PE_pcrel)
    return false;

  /* If we can't get the assembler to emit only .debug_frame, and we don't need
     dwarf2 unwind info for exceptions, then emit .debug_frame by hand.  */
  if (!HAVE_GAS_CFI_SECTIONS_DIRECTIVE
      && !flag_unwind_tables && !flag_exceptions
      && targetm.except_unwind_info (&global_options) != UI_DWARF2)
    return false;

  saved_do_cfi_asm = true;
  return true;
}

/* The size of the target's pointer type.  */
#ifndef PTR_SIZE
#define PTR_SIZE (POINTER_SIZE / BITS_PER_UNIT)
#endif

/* Array of RTXes referenced by the debugging information, which therefore
   must be kept around forever.  */
static GTY(()) VEC(rtx,gc) *used_rtx_array;

/* A pointer to the base of a list of incomplete types which might be
   completed at some later time.  incomplete_types_list needs to be a
   VEC(tree,gc) because we want to tell the garbage collector about
   it.  */
static GTY(()) VEC(tree,gc) *incomplete_types;

/* A pointer to the base of a table of references to declaration
   scopes.  This table is a display which tracks the nesting
   of declaration scopes at the current scope and containing
   scopes.  This table is used to find the proper place to
   define type declaration DIE's.  */
static GTY(()) VEC(tree,gc) *decl_scope_table;

/* Pointers to various DWARF2 sections.  */
static GTY(()) section *debug_info_section;
static GTY(()) section *debug_abbrev_section;
static GTY(()) section *debug_aranges_section;
static GTY(()) section *debug_macinfo_section;
static GTY(()) section *debug_line_section;
static GTY(()) section *debug_loc_section;
static GTY(()) section *debug_pubnames_section;
static GTY(()) section *debug_pubtypes_section;
static GTY(()) section *debug_dcall_section;
static GTY(()) section *debug_vcall_section;
static GTY(()) section *debug_str_section;
static GTY(()) section *debug_ranges_section;
static GTY(()) section *debug_frame_section;

/* Personality decl of current unit.  Used only when assembler does not support
   personality CFI.  */
static GTY(()) rtx current_unit_personality;

/* How to start an assembler comment.  */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif

typedef struct dw_cfi_struct *dw_cfi_ref;
typedef struct dw_fde_struct *dw_fde_ref;
typedef union  dw_cfi_oprnd_struct *dw_cfi_oprnd_ref;

/* Call frames are described using a sequence of Call Frame
   Information instructions.  The register number, offset
   and address fields are provided as possible operands;
   their use is selected by the opcode field.  */

enum dw_cfi_oprnd_type {
  dw_cfi_oprnd_unused,
  dw_cfi_oprnd_reg_num,
  dw_cfi_oprnd_offset,
  dw_cfi_oprnd_addr,
  dw_cfi_oprnd_loc
};

typedef union GTY(()) dw_cfi_oprnd_struct {
  unsigned int GTY ((tag ("dw_cfi_oprnd_reg_num"))) dw_cfi_reg_num;
  HOST_WIDE_INT GTY ((tag ("dw_cfi_oprnd_offset"))) dw_cfi_offset;
  const char * GTY ((tag ("dw_cfi_oprnd_addr"))) dw_cfi_addr;
  struct dw_loc_descr_struct * GTY ((tag ("dw_cfi_oprnd_loc"))) dw_cfi_loc;
}
dw_cfi_oprnd;

typedef struct GTY(()) dw_cfi_struct {
  dw_cfi_ref dw_cfi_next;
  enum dwarf_call_frame_info dw_cfi_opc;
  dw_cfi_oprnd GTY ((desc ("dw_cfi_oprnd1_desc (%1.dw_cfi_opc)")))
    dw_cfi_oprnd1;
  dw_cfi_oprnd GTY ((desc ("dw_cfi_oprnd2_desc (%1.dw_cfi_opc)")))
    dw_cfi_oprnd2;
}
dw_cfi_node;

/* This is how we define the location of the CFA. We use to handle it
   as REG + OFFSET all the time,  but now it can be more complex.
   It can now be either REG + CFA_OFFSET or *(REG + BASE_OFFSET) + CFA_OFFSET.
   Instead of passing around REG and OFFSET, we pass a copy
   of this structure.  */
typedef struct cfa_loc {
  HOST_WIDE_INT offset;
  HOST_WIDE_INT base_offset;
  unsigned int reg;
  BOOL_BITFIELD indirect : 1;  /* 1 if CFA is accessed via a dereference.  */
  BOOL_BITFIELD in_use : 1;    /* 1 if a saved cfa is stored here.  */
} dw_cfa_location;

/* All call frame descriptions (FDE's) in the GCC generated DWARF
   refer to a single Common Information Entry (CIE), defined at
   the beginning of the .debug_frame section.  This use of a single
   CIE obviates the need to keep track of multiple CIE's
   in the DWARF generation routines below.  */

typedef struct GTY(()) dw_fde_struct {
  tree decl;
  const char *dw_fde_begin;
  const char *dw_fde_current_label;
  const char *dw_fde_end;
  const char *dw_fde_vms_end_prologue;
  const char *dw_fde_vms_begin_epilogue;
  const char *dw_fde_hot_section_label;
  const char *dw_fde_hot_section_end_label;
  const char *dw_fde_unlikely_section_label;
  const char *dw_fde_unlikely_section_end_label;
  dw_cfi_ref dw_fde_cfi;
  dw_cfi_ref dw_fde_switch_cfi; /* Last CFI before switching sections.  */
  HOST_WIDE_INT stack_realignment;
  unsigned funcdef_number;
  /* Dynamic realign argument pointer register.  */
  unsigned int drap_reg;
  /* Virtual dynamic realign argument pointer register.  */
  unsigned int vdrap_reg;
  /* These 3 flags are copied from rtl_data in function.h.  */
  unsigned all_throwers_are_sibcalls : 1;
  unsigned uses_eh_lsda : 1;
  unsigned nothrow : 1;
  /* Whether we did stack realign in this call frame.  */
  unsigned stack_realign : 1;
  /* Whether dynamic realign argument pointer register has been saved.  */
  unsigned drap_reg_saved: 1;
  /* True iff dw_fde_begin label is in text_section or cold_text_section.  */
  unsigned in_std_section : 1;
  /* True iff dw_fde_unlikely_section_label is in text_section or
     cold_text_section.  */
  unsigned cold_in_std_section : 1;
  /* True iff switched sections.  */
  unsigned dw_fde_switched_sections : 1;
  /* True iff switching from cold to hot section.  */
  unsigned dw_fde_switched_cold_to_hot : 1;
}
dw_fde_node;

/* Maximum size (in bytes) of an artificially generated label.  */
#define MAX_ARTIFICIAL_LABEL_BYTES      30

/* The size of addresses as they appear in the Dwarf 2 data.
   Some architectures use word addresses to refer to code locations,
   but Dwarf 2 info always uses byte addresses.  On such machines,
   Dwarf 2 addresses need to be larger than the architecture's
   pointers.  */
#ifndef DWARF2_ADDR_SIZE
#define DWARF2_ADDR_SIZE (POINTER_SIZE / BITS_PER_UNIT)
#endif

/* The size in bytes of a DWARF field indicating an offset or length
   relative to a debug info section, specified to be 4 bytes in the
   DWARF-2 specification.  The SGI/MIPS ABI defines it to be the same
   as PTR_SIZE.  */

#ifndef DWARF_OFFSET_SIZE
#define DWARF_OFFSET_SIZE 4
#endif

/* The size in bytes of a DWARF 4 type signature.  */

#ifndef DWARF_TYPE_SIGNATURE_SIZE
#define DWARF_TYPE_SIGNATURE_SIZE 8
#endif

/* According to the (draft) DWARF 3 specification, the initial length
   should either be 4 or 12 bytes.  When it's 12 bytes, the first 4
   bytes are 0xffffffff, followed by the length stored in the next 8
   bytes.

   However, the SGI/MIPS ABI uses an initial length which is equal to
   DWARF_OFFSET_SIZE.  It is defined (elsewhere) accordingly.  */

#ifndef DWARF_INITIAL_LENGTH_SIZE
#define DWARF_INITIAL_LENGTH_SIZE (DWARF_OFFSET_SIZE == 4 ? 4 : 12)
#endif

/* Round SIZE up to the nearest BOUNDARY.  */
#define DWARF_ROUND(SIZE,BOUNDARY) \
  ((((SIZE) + (BOUNDARY) - 1) / (BOUNDARY)) * (BOUNDARY))

/* Offsets recorded in opcodes are a multiple of this alignment factor.  */
#ifndef DWARF_CIE_DATA_ALIGNMENT
#ifdef STACK_GROWS_DOWNWARD
#define DWARF_CIE_DATA_ALIGNMENT (-((int) UNITS_PER_WORD))
#else
#define DWARF_CIE_DATA_ALIGNMENT ((int) UNITS_PER_WORD)
#endif
#endif

/* CIE identifier.  */
#if HOST_BITS_PER_WIDE_INT >= 64
#define DWARF_CIE_ID \
  (unsigned HOST_WIDE_INT) (DWARF_OFFSET_SIZE == 4 ? DW_CIE_ID : DW64_CIE_ID)
#else
#define DWARF_CIE_ID DW_CIE_ID
#endif

/* A pointer to the base of a table that contains frame description
   information for each routine.  */
static GTY((length ("fde_table_allocated"))) dw_fde_ref fde_table;

/* Number of elements currently allocated for fde_table.  */
static GTY(()) unsigned fde_table_allocated;

/* Number of elements in fde_table currently in use.  */
static GTY(()) unsigned fde_table_in_use;

/* Size (in elements) of increments by which we may expand the
   fde_table.  */
#define FDE_TABLE_INCREMENT 256

/* Get the current fde_table entry we should use.  */

static inline dw_fde_ref
current_fde (void)
{
  return fde_table_in_use ? &fde_table[fde_table_in_use - 1] : NULL;
}

/* A list of call frame insns for the CIE.  */
static GTY(()) dw_cfi_ref cie_cfi_head;

/* Some DWARF extensions (e.g., MIPS/SGI) implement a subprogram
   attribute that accelerates the lookup of the FDE associated
   with the subprogram.  This variable holds the table index of the FDE
   associated with the current function (body) definition.  */
static unsigned current_funcdef_fde;

struct GTY(()) indirect_string_node {
  const char *str;
  unsigned int refcount;
  enum dwarf_form form;
  char *label;
};

static GTY ((param_is (struct indirect_string_node))) htab_t debug_str_hash;

/* True if the compilation unit has location entries that reference
   debug strings.  */
static GTY(()) bool debug_str_hash_forced = false;

static GTY(()) int dw2_string_counter;
static GTY(()) unsigned long dwarf2out_cfi_label_num;

/* True if the compilation unit places functions in more than one section.  */
static GTY(()) bool have_multiple_function_sections = false;

/* Whether the default text and cold text sections have been used at all.  */

static GTY(()) bool text_section_used = false;
static GTY(()) bool cold_text_section_used = false;

/* The default cold text section.  */
static GTY(()) section *cold_text_section;

/* Forward declarations for functions defined in this file.  */

static char *stripattributes (const char *);
static const char *dwarf_cfi_name (unsigned);
static dw_cfi_ref new_cfi (void);
static void add_cfi (dw_cfi_ref *, dw_cfi_ref);
static void add_fde_cfi (const char *, dw_cfi_ref);
static void lookup_cfa_1 (dw_cfi_ref, dw_cfa_location *, dw_cfa_location *);
static void lookup_cfa (dw_cfa_location *);
static void reg_save (const char *, unsigned, unsigned, HOST_WIDE_INT);
static void initial_return_save (rtx);
static HOST_WIDE_INT stack_adjust_offset (const_rtx, HOST_WIDE_INT,
                                          HOST_WIDE_INT);
static void output_cfi (dw_cfi_ref, dw_fde_ref, int);
static void output_cfi_directive (dw_cfi_ref);
static void output_call_frame_info (int);
static void dwarf2out_note_section_used (void);
static bool clobbers_queued_reg_save (const_rtx);
static void dwarf2out_frame_debug_expr (rtx, const char *);

/* Support for complex CFA locations.  */
static void output_cfa_loc (dw_cfi_ref);
static void output_cfa_loc_raw (dw_cfi_ref);
static void get_cfa_from_loc_descr (dw_cfa_location *,
                                    struct dw_loc_descr_struct *);
static struct dw_loc_descr_struct *build_cfa_loc
  (dw_cfa_location *, HOST_WIDE_INT);
static struct dw_loc_descr_struct *build_cfa_aligned_loc
  (HOST_WIDE_INT, HOST_WIDE_INT);
static void def_cfa_1 (const char *, dw_cfa_location *);
static struct dw_loc_descr_struct *mem_loc_descriptor
  (rtx, enum machine_mode mode, enum var_init_status);

/* How to start an assembler comment.  */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif

/* Data and reference forms for relocatable data.  */
#define DW_FORM_data (DWARF_OFFSET_SIZE == 8 ? DW_FORM_data8 : DW_FORM_data4)
#define DW_FORM_ref (DWARF_OFFSET_SIZE == 8 ? DW_FORM_ref8 : DW_FORM_ref4)

#ifndef DEBUG_FRAME_SECTION
#define DEBUG_FRAME_SECTION     ".debug_frame"
#endif

#ifndef FUNC_BEGIN_LABEL
#define FUNC_BEGIN_LABEL        "LFB"
#endif

#ifndef FUNC_END_LABEL
#define FUNC_END_LABEL          "LFE"
#endif

#ifndef PROLOGUE_END_LABEL
#define PROLOGUE_END_LABEL      "LPE"
#endif

#ifndef EPILOGUE_BEGIN_LABEL
#define EPILOGUE_BEGIN_LABEL    "LEB"
#endif

#ifndef FRAME_BEGIN_LABEL
#define FRAME_BEGIN_LABEL       "Lframe"
#endif
#define CIE_AFTER_SIZE_LABEL    "LSCIE"
#define CIE_END_LABEL           "LECIE"
#define FDE_LABEL               "LSFDE"
#define FDE_AFTER_SIZE_LABEL    "LASFDE"
#define FDE_END_LABEL           "LEFDE"
#define LINE_NUMBER_BEGIN_LABEL "LSLT"
#define LINE_NUMBER_END_LABEL   "LELT"
#define LN_PROLOG_AS_LABEL      "LASLTP"
#define LN_PROLOG_END_LABEL     "LELTP"
#define DIE_LABEL_PREFIX        "DW"

/* The DWARF 2 CFA column which tracks the return address.  Normally this
   is the column for PC, or the first column after all of the hard
   registers.  */
#ifndef DWARF_FRAME_RETURN_COLUMN
#ifdef PC_REGNUM
#define DWARF_FRAME_RETURN_COLUMN       DWARF_FRAME_REGNUM (PC_REGNUM)
#else
#define DWARF_FRAME_RETURN_COLUMN       DWARF_FRAME_REGISTERS
#endif
#endif

/* The mapping from gcc register number to DWARF 2 CFA column number.  By
   default, we just provide columns for all registers.  */
#ifndef DWARF_FRAME_REGNUM
#define DWARF_FRAME_REGNUM(REG) DBX_REGISTER_NUMBER (REG)
#endif
\f
/* Match the base name of a file to the base name of a compilation unit. */

static int
matches_main_base (const char *path)
{
  /* Cache the last query. */
  static const char *last_path = NULL;
  static int last_match = 0;
  if (path != last_path)
    {
      const char *base;
      int length = base_of_path (path, &base);
      last_path = path;
      last_match = (length == main_input_baselength
                    && memcmp (base, main_input_basename, length) == 0);
    }
  return last_match;
}

#ifdef DEBUG_DEBUG_STRUCT

static int
dump_struct_debug (tree type, enum debug_info_usage usage,
                   enum debug_struct_file criterion, int generic,
                   int matches, int result)
{
  /* Find the type name. */
  tree type_decl = TYPE_STUB_DECL (type);
  tree t = type_decl;
  const char *name = 0;
  if (TREE_CODE (t) == TYPE_DECL)
    t = DECL_NAME (t);
  if (t)
    name = IDENTIFIER_POINTER (t);

  fprintf (stderr, "    struct %d %s %s %s %s %d %p %s\n",
           criterion,
           DECL_IN_SYSTEM_HEADER (type_decl) ? "sys" : "usr",
           matches ? "bas" : "hdr",
           generic ? "gen" : "ord",
           usage == DINFO_USAGE_DFN ? ";" :
             usage == DINFO_USAGE_DIR_USE ? "." : "*",
           result,
           (void*) type_decl, name);
  return result;
}
#define DUMP_GSTRUCT(type, usage, criterion, generic, matches, result) \
  dump_struct_debug (type, usage, criterion, generic, matches, result)

#else

#define DUMP_GSTRUCT(type, usage, criterion, generic, matches, result) \
  (result)

#endif

static bool
should_emit_struct_debug (tree type, enum debug_info_usage usage)
{
  enum debug_struct_file criterion;
  tree type_decl;
  bool generic = lang_hooks.types.generic_p (type);

  if (generic)
    criterion = debug_struct_generic[usage];
  else
    criterion = debug_struct_ordinary[usage];

  if (criterion == DINFO_STRUCT_FILE_NONE)
    return DUMP_GSTRUCT (type, usage, criterion, generic, false, false);
  if (criterion == DINFO_STRUCT_FILE_ANY)
    return DUMP_GSTRUCT (type, usage, criterion, generic, false, true);

  type_decl = TYPE_STUB_DECL (type);

  if (criterion == DINFO_STRUCT_FILE_SYS && DECL_IN_SYSTEM_HEADER (type_decl))
    return DUMP_GSTRUCT (type, usage, criterion, generic, false, true);

  if (matches_main_base (DECL_SOURCE_FILE (type_decl)))
    return DUMP_GSTRUCT (type, usage, criterion, generic, true, true);
  return DUMP_GSTRUCT (type, usage, criterion, generic, false, false);
}
\f
/* Hook used by __throw.  */

rtx
expand_builtin_dwarf_sp_column (void)
{
  unsigned int dwarf_regnum = DWARF_FRAME_REGNUM (STACK_POINTER_REGNUM);
  return GEN_INT (DWARF2_FRAME_REG_OUT (dwarf_regnum, 1));
}

/* Return a pointer to a copy of the section string name S with all
   attributes stripped off, and an asterisk prepended (for assemble_name).  */

static inline char *
stripattributes (const char *s)
{
  char *stripped = XNEWVEC (char, strlen (s) + 2);
  char *p = stripped;

  *p++ = '*';

  while (*s && *s != ',')
    *p++ = *s++;

  *p = '\0';
  return stripped;
}

/* MEM is a memory reference for the register size table, each element of
   which has mode MODE.  Initialize column C as a return address column.  */

static void
init_return_column_size (enum machine_mode mode, rtx mem, unsigned int c)
{
  HOST_WIDE_INT offset = c * GET_MODE_SIZE (mode);
  HOST_WIDE_INT size = GET_MODE_SIZE (Pmode);
  emit_move_insn (adjust_address (mem, mode, offset), GEN_INT (size));
}

/* Divide OFF by DWARF_CIE_DATA_ALIGNMENT, asserting no remainder.  */

static inline HOST_WIDE_INT
div_data_align (HOST_WIDE_INT off)
{
  HOST_WIDE_INT r = off / DWARF_CIE_DATA_ALIGNMENT;
  gcc_assert (r * DWARF_CIE_DATA_ALIGNMENT == off);
  return r;
}

/* Return true if we need a signed version of a given opcode
   (e.g. DW_CFA_offset_extended_sf vs DW_CFA_offset_extended).  */

static inline bool
need_data_align_sf_opcode (HOST_WIDE_INT off)
{
  return DWARF_CIE_DATA_ALIGNMENT < 0 ? off > 0 : off < 0;
}

/* Generate code to initialize the register size table.  */

void
expand_builtin_init_dwarf_reg_sizes (tree address)
{
  unsigned int i;
  enum machine_mode mode = TYPE_MODE (char_type_node);
  rtx addr = expand_normal (address);
  rtx mem = gen_rtx_MEM (BLKmode, addr);
  bool wrote_return_column = false;

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      int rnum = DWARF2_FRAME_REG_OUT (DWARF_FRAME_REGNUM (i), 1);

      if (rnum < DWARF_FRAME_REGISTERS)
        {
          HOST_WIDE_INT offset = rnum * GET_MODE_SIZE (mode);
          enum machine_mode save_mode = reg_raw_mode[i];
          HOST_WIDE_INT size;

          if (HARD_REGNO_CALL_PART_CLOBBERED (i, save_mode))
            save_mode = choose_hard_reg_mode (i, 1, true);
          if (DWARF_FRAME_REGNUM (i) == DWARF_FRAME_RETURN_COLUMN)
            {
              if (save_mode == VOIDmode)
                continue;
              wrote_return_column = true;
            }
          size = GET_MODE_SIZE (save_mode);
          if (offset < 0)
            continue;

          emit_move_insn (adjust_address (mem, mode, offset),
                          gen_int_mode (size, mode));
        }
    }

  if (!wrote_return_column)
    init_return_column_size (mode, mem, DWARF_FRAME_RETURN_COLUMN);

#ifdef DWARF_ALT_FRAME_RETURN_COLUMN
  init_return_column_size (mode, mem, DWARF_ALT_FRAME_RETURN_COLUMN);
#endif

  targetm.init_dwarf_reg_sizes_extra (address);
}

/* Convert a DWARF call frame info. operation to its string name */

static const char *
dwarf_cfi_name (unsigned int cfi_opc)
{
  switch (cfi_opc)
    {
    case DW_CFA_advance_loc:
      return "DW_CFA_advance_loc";
    case DW_CFA_offset:
      return "DW_CFA_offset";
    case DW_CFA_restore:
      return "DW_CFA_restore";
    case DW_CFA_nop:
      return "DW_CFA_nop";
    case DW_CFA_set_loc:
      return "DW_CFA_set_loc";
    case DW_CFA_advance_loc1:
      return "DW_CFA_advance_loc1";
    case DW_CFA_advance_loc2:
      return "DW_CFA_advance_loc2";
    case DW_CFA_advance_loc4:
      return "DW_CFA_advance_loc4";
    case DW_CFA_offset_extended:
      return "DW_CFA_offset_extended";
    case DW_CFA_restore_extended:
      return "DW_CFA_restore_extended";
    case DW_CFA_undefined:
      return "DW_CFA_undefined";
    case DW_CFA_same_value:
      return "DW_CFA_same_value";
    case DW_CFA_register:
      return "DW_CFA_register";
    case DW_CFA_remember_state:
      return "DW_CFA_remember_state";
    case DW_CFA_restore_state:
      return "DW_CFA_restore_state";
    case DW_CFA_def_cfa:
      return "DW_CFA_def_cfa";
    case DW_CFA_def_cfa_register:
      return "DW_CFA_def_cfa_register";
    case DW_CFA_def_cfa_offset:
      return "DW_CFA_def_cfa_offset";

    /* DWARF 3 */
    case DW_CFA_def_cfa_expression:
      return "DW_CFA_def_cfa_expression";
    case DW_CFA_expression:
      return "DW_CFA_expression";
    case DW_CFA_offset_extended_sf:
      return "DW_CFA_offset_extended_sf";
    case DW_CFA_def_cfa_sf:
      return "DW_CFA_def_cfa_sf";
    case DW_CFA_def_cfa_offset_sf:
      return "DW_CFA_def_cfa_offset_sf";

    /* SGI/MIPS specific */
    case DW_CFA_MIPS_advance_loc8:
      return "DW_CFA_MIPS_advance_loc8";

    /* GNU extensions */
    case DW_CFA_GNU_window_save:
      return "DW_CFA_GNU_window_save";
    case DW_CFA_GNU_args_size:
      return "DW_CFA_GNU_args_size";
    case DW_CFA_GNU_negative_offset_extended:
      return "DW_CFA_GNU_negative_offset_extended";

    default:
      return "DW_CFA_<unknown>";
    }
}

/* Return a pointer to a newly allocated Call Frame Instruction.  */

static inline dw_cfi_ref
new_cfi (void)
{
  dw_cfi_ref cfi = ggc_alloc_dw_cfi_node ();

  cfi->dw_cfi_next = NULL;
  cfi->dw_cfi_oprnd1.dw_cfi_reg_num = 0;
  cfi->dw_cfi_oprnd2.dw_cfi_reg_num = 0;

  return cfi;
}

/* Add a Call Frame Instruction to list of instructions.  */

static inline void
add_cfi (dw_cfi_ref *list_head, dw_cfi_ref cfi)
{
  dw_cfi_ref *p;
  dw_fde_ref fde = current_fde ();

  /* When DRAP is used, CFA is defined with an expression.  Redefine
     CFA may lead to a different CFA value.   */
  /* ??? Of course, this heuristic fails when we're annotating epilogues,
     because of course we'll always want to redefine the CFA back to the
     stack pointer on the way out.  Where should we move this check?  */
  if (0 && fde && fde->drap_reg != INVALID_REGNUM)
    switch (cfi->dw_cfi_opc)
      {
        case DW_CFA_def_cfa_register:
        case DW_CFA_def_cfa_offset:
        case DW_CFA_def_cfa_offset_sf:
        case DW_CFA_def_cfa:
        case DW_CFA_def_cfa_sf:
          gcc_unreachable ();

        default:
          break;
      }

  /* Find the end of the chain.  */
  for (p = list_head; (*p) != NULL; p = &(*p)->dw_cfi_next)
    ;

  *p = cfi;
}

/* Generate a new label for the CFI info to refer to.  FORCE is true
   if a label needs to be output even when using .cfi_* directives.  */

char *
dwarf2out_cfi_label (bool force)
{
  static char label[20];

  if (!force && dwarf2out_do_cfi_asm ())
    {
      /* In this case, we will be emitting the asm directive instead of
         the label, so just return a placeholder to keep the rest of the
         interfaces happy.  */
      strcpy (label, "<do not output>");
    }
  else
    {
      int num = dwarf2out_cfi_label_num++;
      ASM_GENERATE_INTERNAL_LABEL (label, "LCFI", num);
      ASM_OUTPUT_DEBUG_LABEL (asm_out_file, "LCFI", num);
    }

  return label;
}

/* True if remember_state should be emitted before following CFI directive.  */
static bool emit_cfa_remember;

/* True if any CFI directives were emitted at the current insn.  */
static bool any_cfis_emitted;

/* Add CFI to the current fde at the PC value indicated by LABEL if specified,
   or to the CIE if LABEL is NULL.  */

static void
add_fde_cfi (const char *label, dw_cfi_ref cfi)
{
  dw_cfi_ref *list_head;

  if (emit_cfa_remember)
    {
      dw_cfi_ref cfi_remember;

      /* Emit the state save.  */
      emit_cfa_remember = false;
      cfi_remember = new_cfi ();
      cfi_remember->dw_cfi_opc = DW_CFA_remember_state;
      add_fde_cfi (label, cfi_remember);
    }

  list_head = &cie_cfi_head;

  if (dwarf2out_do_cfi_asm ())
    {
      if (label)
        {
          dw_fde_ref fde = current_fde ();

          gcc_assert (fde != NULL);

          /* We still have to add the cfi to the list so that lookup_cfa
             works later on.  When -g2 and above we even need to force
             emitting of CFI labels and add to list a DW_CFA_set_loc for
             convert_cfa_to_fb_loc_list purposes.  If we're generating
             DWARF3 output we use DW_OP_call_frame_cfa and so don't use
             convert_cfa_to_fb_loc_list.  */
          if (dwarf_version == 2
              && debug_info_level > DINFO_LEVEL_TERSE
              && (write_symbols == DWARF2_DEBUG
                  || write_symbols == VMS_AND_DWARF2_DEBUG))
            {
              switch (cfi->dw_cfi_opc)
                {
                case DW_CFA_def_cfa_offset:
                case DW_CFA_def_cfa_offset_sf:
                case DW_CFA_def_cfa_register:
                case DW_CFA_def_cfa:
                case DW_CFA_def_cfa_sf:
                case DW_CFA_def_cfa_expression:
                case DW_CFA_restore_state:
                  if (*label == 0 || strcmp (label, "<do not output>") == 0)
                    label = dwarf2out_cfi_label (true);

                  if (fde->dw_fde_current_label == NULL
                      || strcmp (label, fde->dw_fde_current_label) != 0)
                    {
                      dw_cfi_ref xcfi;

                      label = xstrdup (label);

                      /* Set the location counter to the new label.  */
                      xcfi = new_cfi ();
                      /* It doesn't metter whether DW_CFA_set_loc
                         or DW_CFA_advance_loc4 is added here, those aren't
                         emitted into assembly, only looked up by
                         convert_cfa_to_fb_loc_list.  */
                      xcfi->dw_cfi_opc = DW_CFA_set_loc;
                      xcfi->dw_cfi_oprnd1.dw_cfi_addr = label;
                      add_cfi (&fde->dw_fde_cfi, xcfi);
                      fde->dw_fde_current_label = label;
                    }
                  break;
                default:
                  break;
                }
            }

          output_cfi_directive (cfi);

          list_head = &fde->dw_fde_cfi;
          any_cfis_emitted = true;
        }
      /* ??? If this is a CFI for the CIE, we don't emit.  This
         assumes that the standard CIE contents that the assembler
         uses matches the standard CIE contents that the compiler
         uses.  This is probably a bad assumption.  I'm not quite
         sure how to address this for now.  */
    }
  else if (label)
    {
      dw_fde_ref fde = current_fde ();

      gcc_assert (fde != NULL);

      if (*label == 0)
        label = dwarf2out_cfi_label (false);

      if (fde->dw_fde_current_label == NULL
          || strcmp (label, fde->dw_fde_current_label) != 0)
        {
          dw_cfi_ref xcfi;

          label = xstrdup (label);

          /* Set the location counter to the new label.  */
          xcfi = new_cfi ();
          /* If we have a current label, advance from there, otherwise
             set the location directly using set_loc.  */
          xcfi->dw_cfi_opc = fde->dw_fde_current_label
                             ? DW_CFA_advance_loc4
                             : DW_CFA_set_loc;
          xcfi->dw_cfi_oprnd1.dw_cfi_addr = label;
          add_cfi (&fde->dw_fde_cfi, xcfi);

          fde->dw_fde_current_label = label;
        }

      list_head = &fde->dw_fde_cfi;
      any_cfis_emitted = true;
    }

  add_cfi (list_head, cfi);
}

/* Subroutine of lookup_cfa.  */

static void
lookup_cfa_1 (dw_cfi_ref cfi, dw_cfa_location *loc, dw_cfa_location *remember)
{
  switch (cfi->dw_cfi_opc)
    {
    case DW_CFA_def_cfa_offset:
    case DW_CFA_def_cfa_offset_sf:
      loc->offset = cfi->dw_cfi_oprnd1.dw_cfi_offset;
      break;
    case DW_CFA_def_cfa_register:
      loc->reg = cfi->dw_cfi_oprnd1.dw_cfi_reg_num;
      break;
    case DW_CFA_def_cfa:
    case DW_CFA_def_cfa_sf:
      loc->reg = cfi->dw_cfi_oprnd1.dw_cfi_reg_num;
      loc->offset = cfi->dw_cfi_oprnd2.dw_cfi_offset;
      break;
    case DW_CFA_def_cfa_expression:
      get_cfa_from_loc_descr (loc, cfi->dw_cfi_oprnd1.dw_cfi_loc);
      break;

    case DW_CFA_remember_state:
      gcc_assert (!remember->in_use);
      *remember = *loc;
      remember->in_use = 1;
      break;
    case DW_CFA_restore_state:
      gcc_assert (remember->in_use);
      *loc = *remember;
      remember->in_use = 0;
      break;

    default:
      break;
    }
}

/* Find the previous value for the CFA.  */

static void
lookup_cfa (dw_cfa_location *loc)
{
  dw_cfi_ref cfi;
  dw_fde_ref fde;
  dw_cfa_location remember;

  memset (loc, 0, sizeof (*loc));
  loc->reg = INVALID_REGNUM;
  remember = *loc;

  for (cfi = cie_cfi_head; cfi; cfi = cfi->dw_cfi_next)
    lookup_cfa_1 (cfi, loc, &remember);

  fde = current_fde ();
  if (fde)
    for (cfi = fde->dw_fde_cfi; cfi; cfi = cfi->dw_cfi_next)
      lookup_cfa_1 (cfi, loc, &remember);
}

/* The current rule for calculating the DWARF2 canonical frame address.  */
static dw_cfa_location cfa;

/* The register used for saving registers to the stack, and its offset
   from the CFA.  */
static dw_cfa_location cfa_store;

/* The current save location around an epilogue.  */
static dw_cfa_location cfa_remember;

/* The running total of the size of arguments pushed onto the stack.  */
static HOST_WIDE_INT args_size;

/* The last args_size we actually output.  */
static HOST_WIDE_INT old_args_size;

/* Entry point to update the canonical frame address (CFA).
   LABEL is passed to add_fde_cfi.  The value of CFA is now to be
   calculated from REG+OFFSET.  */

void
dwarf2out_def_cfa (const char *label, unsigned int reg, HOST_WIDE_INT offset)
{
  dw_cfa_location loc;
  loc.indirect = 0;
  loc.base_offset = 0;
  loc.reg = reg;
  loc.offset = offset;
  def_cfa_1 (label, &loc);
}

/* Determine if two dw_cfa_location structures define the same data.  */

static bool
cfa_equal_p (const dw_cfa_location *loc1, const dw_cfa_location *loc2)
{
  return (loc1->reg == loc2->reg
          && loc1->offset == loc2->offset
          && loc1->indirect == loc2->indirect
          && (loc1->indirect == 0
              || loc1->base_offset == loc2->base_offset));
}

/* This routine does the actual work.  The CFA is now calculated from
   the dw_cfa_location structure.  */

static void
def_cfa_1 (const char *label, dw_cfa_location *loc_p)
{
  dw_cfi_ref cfi;
  dw_cfa_location old_cfa, loc;

  cfa = *loc_p;
  loc = *loc_p;

  if (cfa_store.reg == loc.reg && loc.indirect == 0)
    cfa_store.offset = loc.offset;

  loc.reg = DWARF_FRAME_REGNUM (loc.reg);
  lookup_cfa (&old_cfa);

  /* If nothing changed, no need to issue any call frame instructions.  */
  if (cfa_equal_p (&loc, &old_cfa))
    return;

  cfi = new_cfi ();

  if (loc.reg == old_cfa.reg && !loc.indirect && !old_cfa.indirect)
    {
      /* Construct a "DW_CFA_def_cfa_offset <offset>" instruction, indicating
         the CFA register did not change but the offset did.  The data
         factoring for DW_CFA_def_cfa_offset_sf happens in output_cfi, or
         in the assembler via the .cfi_def_cfa_offset directive.  */
      if (loc.offset < 0)
        cfi->dw_cfi_opc = DW_CFA_def_cfa_offset_sf;
      else
        cfi->dw_cfi_opc = DW_CFA_def_cfa_offset;
      cfi->dw_cfi_oprnd1.dw_cfi_offset = loc.offset;
    }

#ifndef MIPS_DEBUGGING_INFO  /* SGI dbx thinks this means no offset.  */
  else if (loc.offset == old_cfa.offset
           && old_cfa.reg != INVALID_REGNUM
           && !loc.indirect
           && !old_cfa.indirect)
    {
      /* Construct a "DW_CFA_def_cfa_register <register>" instruction,
         indicating the CFA register has changed to <register> but the
         offset has not changed.  */
      cfi->dw_cfi_opc = DW_CFA_def_cfa_register;
      cfi->dw_cfi_oprnd1.dw_cfi_reg_num = loc.reg;
    }
#endif

  else if (loc.indirect == 0)
    {
      /* Construct a "DW_CFA_def_cfa <register> <offset>" instruction,
         indicating the CFA register has changed to <register> with
         the specified offset.  The data factoring for DW_CFA_def_cfa_sf
         happens in output_cfi, or in the assembler via the .cfi_def_cfa
         directive.  */
      if (loc.offset < 0)
        cfi->dw_cfi_opc = DW_CFA_def_cfa_sf;
      else
        cfi->dw_cfi_opc = DW_CFA_def_cfa;
      cfi->dw_cfi_oprnd1.dw_cfi_reg_num = loc.reg;
      cfi->dw_cfi_oprnd2.dw_cfi_offset = loc.offset;
    }
  else
    {
      /* Construct a DW_CFA_def_cfa_expression instruction to
         calculate the CFA using a full location expression since no
         register-offset pair is available.  */
      struct dw_loc_descr_struct *loc_list;

      cfi->dw_cfi_opc = DW_CFA_def_cfa_expression;
      loc_list = build_cfa_loc (&loc, 0);
      cfi->dw_cfi_oprnd1.dw_cfi_loc = loc_list;
    }

  add_fde_cfi (label, cfi);
}

/* Add the CFI for saving a register.  REG is the CFA column number.
   LABEL is passed to add_fde_cfi.
   If SREG is -1, the register is saved at OFFSET from the CFA;
   otherwise it is saved in SREG.  */

static void
reg_save (const char *label, unsigned int reg, unsigned int sreg, HOST_WIDE_INT offset)
{
  dw_cfi_ref cfi = new_cfi ();
  dw_fde_ref fde = current_fde ();

  cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;

  /* When stack is aligned, store REG using DW_CFA_expression with
     FP.  */
  if (fde
      && fde->stack_realign
      && sreg == INVALID_REGNUM)
    {
      cfi->dw_cfi_opc = DW_CFA_expression;
      cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;
      cfi->dw_cfi_oprnd2.dw_cfi_loc
        = build_cfa_aligned_loc (offset, fde->stack_realignment);
    }
  else if (sreg == INVALID_REGNUM)
    {
      if (need_data_align_sf_opcode (offset))
        cfi->dw_cfi_opc = DW_CFA_offset_extended_sf;
      else if (reg & ~0x3f)
        cfi->dw_cfi_opc = DW_CFA_offset_extended;
      else
        cfi->dw_cfi_opc = DW_CFA_offset;
      cfi->dw_cfi_oprnd2.dw_cfi_offset = offset;
    }
  else if (sreg == reg)
    cfi->dw_cfi_opc = DW_CFA_same_value;
  else
    {
      cfi->dw_cfi_opc = DW_CFA_register;
      cfi->dw_cfi_oprnd2.dw_cfi_reg_num = sreg;
    }

  add_fde_cfi (label, cfi);
}

/* Add the CFI for saving a register window.  LABEL is passed to reg_save.
   This CFI tells the unwinder that it needs to restore the window registers
   from the previous frame's window save area.

   ??? Perhaps we should note in the CIE where windows are saved (instead of
   assuming 0(cfa)) and what registers are in the window.  */

void
dwarf2out_window_save (const char *label)
{
  dw_cfi_ref cfi = new_cfi ();

  cfi->dw_cfi_opc = DW_CFA_GNU_window_save;
  add_fde_cfi (label, cfi);
}

/* Entry point for saving a register to the stack.  REG is the GCC register
   number.  LABEL and OFFSET are passed to reg_save.  */

void
dwarf2out_reg_save (const char *label, unsigned int reg, HOST_WIDE_INT offset)
{
  reg_save (label, DWARF_FRAME_REGNUM (reg), INVALID_REGNUM, offset);
}

/* Entry point for saving the return address in the stack.
   LABEL and OFFSET are passed to reg_save.  */

void
dwarf2out_return_save (const char *label, HOST_WIDE_INT offset)
{
  reg_save (label, DWARF_FRAME_RETURN_COLUMN, INVALID_REGNUM, offset);
}

/* Entry point for saving the return address in a register.
   LABEL and SREG are passed to reg_save.  */

void
dwarf2out_return_reg (const char *label, unsigned int sreg)
{
  reg_save (label, DWARF_FRAME_RETURN_COLUMN, DWARF_FRAME_REGNUM (sreg), 0);
}

/* Record the initial position of the return address.  RTL is
   INCOMING_RETURN_ADDR_RTX.  */

static void
initial_return_save (rtx rtl)
{
  unsigned int reg = INVALID_REGNUM;
  HOST_WIDE_INT offset = 0;

  switch (GET_CODE (rtl))
    {
    case REG:
      /* RA is in a register.  */
      reg = DWARF_FRAME_REGNUM (REGNO (rtl));
      break;

    case MEM:
      /* RA is on the stack.  */
      rtl = XEXP (rtl, 0);
      switch (GET_CODE (rtl))
        {
        case REG:
          gcc_assert (REGNO (rtl) == STACK_POINTER_REGNUM);
          offset = 0;
          break;

        case PLUS:
          gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
          offset = INTVAL (XEXP (rtl, 1));
          break;

        case MINUS:
          gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
          offset = -INTVAL (XEXP (rtl, 1));
          break;

        default:
          gcc_unreachable ();
        }

      break;

    case PLUS:
      /* The return address is at some offset from any value we can
         actually load.  For instance, on the SPARC it is in %i7+8. Just
         ignore the offset for now; it doesn't matter for unwinding frames.  */
      gcc_assert (CONST_INT_P (XEXP (rtl, 1)));
      initial_return_save (XEXP (rtl, 0));
      return;

    default:
      gcc_unreachable ();
    }

  if (reg != DWARF_FRAME_RETURN_COLUMN)
    reg_save (NULL, DWARF_FRAME_RETURN_COLUMN, reg, offset - cfa.offset);
}

/* Given a SET, calculate the amount of stack adjustment it
   contains.  */

static HOST_WIDE_INT
stack_adjust_offset (const_rtx pattern, HOST_WIDE_INT cur_args_size,
                     HOST_WIDE_INT cur_offset)
{
  const_rtx src = SET_SRC (pattern);
  const_rtx dest = SET_DEST (pattern);
  HOST_WIDE_INT offset = 0;
  enum rtx_code code;

  if (dest == stack_pointer_rtx)
    {
      code = GET_CODE (src);

      /* Assume (set (reg sp) (reg whatever)) sets args_size
         level to 0.  */
      if (code == REG && src != stack_pointer_rtx)
        {
          offset = -cur_args_size;
#ifndef STACK_GROWS_DOWNWARD
          offset = -offset;
#endif
          return offset - cur_offset;
        }

      if (! (code == PLUS || code == MINUS)
          || XEXP (src, 0) != stack_pointer_rtx
          || !CONST_INT_P (XEXP (src, 1)))
        return 0;

      /* (set (reg sp) (plus (reg sp) (const_int))) */
      offset = INTVAL (XEXP (src, 1));
      if (code == PLUS)
        offset = -offset;
      return offset;
    }

  if (MEM_P (src) && !MEM_P (dest))
    dest = src;
  if (MEM_P (dest))
    {
      /* (set (mem (pre_dec (reg sp))) (foo)) */
      src = XEXP (dest, 0);
      code = GET_CODE (src);

      switch (code)
        {
        case PRE_MODIFY:
        case POST_MODIFY:
          if (XEXP (src, 0) == stack_pointer_rtx)
            {
              rtx val = XEXP (XEXP (src, 1), 1);
              /* We handle only adjustments by constant amount.  */
              gcc_assert (GET_CODE (XEXP (src, 1)) == PLUS
                          && CONST_INT_P (val));
              offset = -INTVAL (val);
              break;
            }
          return 0;

        case PRE_DEC:
        case POST_DEC:
          if (XEXP (src, 0) == stack_pointer_rtx)
            {
              offset = GET_MODE_SIZE (GET_MODE (dest));
              break;
            }
          return 0;

        case PRE_INC:
        case POST_INC:
          if (XEXP (src, 0) == stack_pointer_rtx)
            {
              offset = -GET_MODE_SIZE (GET_MODE (dest));
              break;
            }
          return 0;

        default:
          return 0;
        }
    }
  else
    return 0;

  return offset;
}

/* Precomputed args_size for CODE_LABELs and BARRIERs preceeding them,
   indexed by INSN_UID.  */

static HOST_WIDE_INT *barrier_args_size;

/* Helper function for compute_barrier_args_size.  Handle one insn.  */

static HOST_WIDE_INT
compute_barrier_args_size_1 (rtx insn, HOST_WIDE_INT cur_args_size,
                             VEC (rtx, heap) **next)
{
  HOST_WIDE_INT offset = 0;
  int i;

  if (! RTX_FRAME_RELATED_P (insn))
    {
      if (prologue_epilogue_contains (insn))
        /* Nothing */;
      else if (GET_CODE (PATTERN (insn)) == SET)
        offset = stack_adjust_offset (PATTERN (insn), cur_args_size, 0);
      else if (GET_CODE (PATTERN (insn)) == PARALLEL
               || GET_CODE (PATTERN (insn)) == SEQUENCE)
        {
          /* There may be stack adjustments inside compound insns.  Search
             for them.  */
          for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
            if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
              offset += stack_adjust_offset (XVECEXP (PATTERN (insn), 0, i),
                                             cur_args_size, offset);
        }
    }
  else
    {
      rtx expr = find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX);

      if (expr)
        {
          expr = XEXP (expr, 0);
          if (GET_CODE (expr) == PARALLEL
              || GET_CODE (expr) == SEQUENCE)
            for (i = 1; i < XVECLEN (expr, 0); i++)
              {
                rtx elem = XVECEXP (expr, 0, i);

                if (GET_CODE (elem) == SET && !RTX_FRAME_RELATED_P (elem))
                  offset += stack_adjust_offset (elem, cur_args_size, offset);
              }
        }
    }

#ifndef STACK_GROWS_DOWNWARD
  offset = -offset;
#endif

  cur_args_size += offset;
  if (cur_args_size < 0)
    cur_args_size = 0;

  if (JUMP_P (insn))
    {
      rtx dest = JUMP_LABEL (insn);

      if (dest)
        {
          if (barrier_args_size [INSN_UID (dest)] < 0)
            {
              barrier_args_size [INSN_UID (dest)] = cur_args_size;
              VEC_safe_push (rtx, heap, *next, dest);
            }
        }
    }

  return cur_args_size;
}

/* Walk the whole function and compute args_size on BARRIERs.  */

static void
compute_barrier_args_size (void)
{
  int max_uid = get_max_uid (), i;
  rtx insn;
  VEC (rtx, heap) *worklist, *next, *tmp;

  barrier_args_size = XNEWVEC (HOST_WIDE_INT, max_uid);
  for (i = 0; i < max_uid; i++)
    barrier_args_size[i] = -1;

  worklist = VEC_alloc (rtx, heap, 20);
  next = VEC_alloc (rtx, heap, 20);
  insn = get_insns ();
  barrier_args_size[INSN_UID (insn)] = 0;
  VEC_quick_push (rtx, worklist, insn);
  for (;;)
    {
      while (!VEC_empty (rtx, worklist))
        {
          rtx prev, body, first_insn;
          HOST_WIDE_INT cur_args_size;

          first_insn = insn = VEC_pop (rtx, worklist);
          cur_args_size = barrier_args_size[INSN_UID (insn)];
          prev = prev_nonnote_insn (insn);
          if (prev && BARRIER_P (prev))
            barrier_args_size[INSN_UID (prev)] = cur_args_size;

          for (; insn; insn = NEXT_INSN (insn))
            {
              if (INSN_DELETED_P (insn) || NOTE_P (insn))
                continue;
              if (BARRIER_P (insn))
                break;

              if (LABEL_P (insn))
                {
                  if (insn == first_insn)
                    continue;
                  else if (barrier_args_size[INSN_UID (insn)] < 0)
                    {
                      barrier_args_size[INSN_UID (insn)] = cur_args_size;
                      continue;
                    }
                  else
                    {
                      /* The insns starting with this label have been
                         already scanned or are in the worklist.  */
                      break;
                    }
                }

              body = PATTERN (insn);
              if (GET_CODE (body) == SEQUENCE)
                {
                  HOST_WIDE_INT dest_args_size = cur_args_size;
                  for (i = 1; i < XVECLEN (body, 0); i++)
                    if (INSN_ANNULLED_BRANCH_P (XVECEXP (body, 0, 0))
                        && INSN_FROM_TARGET_P (XVECEXP (body, 0, i)))
                      dest_args_size
                        = compute_barrier_args_size_1 (XVECEXP (body, 0, i),
                                                       dest_args_size, &next);
                    else
                      cur_args_size
                        = compute_barrier_args_size_1 (XVECEXP (body, 0, i),
                                                       cur_args_size, &next);

                  if (INSN_ANNULLED_BRANCH_P (XVECEXP (body, 0, 0)))
                    compute_barrier_args_size_1 (XVECEXP (body, 0, 0),
                                                 dest_args_size, &next);
                  else
                    cur_args_size
                      = compute_barrier_args_size_1 (XVECEXP (body, 0, 0),
                                                     cur_args_size, &next);
                }
              else
                cur_args_size
                  = compute_barrier_args_size_1 (insn, cur_args_size, &next);
            }
        }

      if (VEC_empty (rtx, next))
        break;

      /* Swap WORKLIST with NEXT and truncate NEXT for next iteration.  */
      tmp = next;
      next = worklist;
      worklist = tmp;
      VEC_truncate (rtx, next, 0);
    }

  VEC_free (rtx, heap, worklist);
  VEC_free (rtx, heap, next);
}

/* Add a CFI to update the running total of the size of arguments
   pushed onto the stack.  */

static void
dwarf2out_args_size (const char *label, HOST_WIDE_INT size)
{
  dw_cfi_ref cfi;

  if (size == old_args_size)
    return;

  old_args_size = size;

  cfi = new_cfi ();
  cfi->dw_cfi_opc = DW_CFA_GNU_args_size;
  cfi->dw_cfi_oprnd1.dw_cfi_offset = size;
  add_fde_cfi (label, cfi);
}

/* Record a stack adjustment of OFFSET bytes.  */

static void
dwarf2out_stack_adjust (HOST_WIDE_INT offset, const char *label)
{
  if (cfa.reg == STACK_POINTER_REGNUM)
    cfa.offset += offset;

  if (cfa_store.reg == STACK_POINTER_REGNUM)
    cfa_store.offset += offset;

  if (ACCUMULATE_OUTGOING_ARGS)
    return;

#ifndef STACK_GROWS_DOWNWARD
  offset = -offset;
#endif

  args_size += offset;
  if (args_size < 0)
    args_size = 0;

  def_cfa_1 (label, &cfa);
  if (flag_asynchronous_unwind_tables)
    dwarf2out_args_size (label, args_size);
}

/* Check INSN to see if it looks like a push or a stack adjustment, and
   make a note of it if it does.  EH uses this information to find out
   how much extra space it needs to pop off the stack.  */

static void
dwarf2out_notice_stack_adjust (rtx insn, bool after_p)
{
  HOST_WIDE_INT offset;
  const char *label;
  int i;

  /* Don't handle epilogues at all.  Certainly it would be wrong to do so
     with this function.  Proper support would require all frame-related
     insns to be marked, and to be able to handle saving state around
     epilogues textually in the middle of the function.  */
  if (prologue_epilogue_contains (insn))
    return;

  /* If INSN is an instruction from target of an annulled branch, the
     effects are for the target only and so current argument size
     shouldn't change at all.  */
  if (final_sequence
      && INSN_ANNULLED_BRANCH_P (XVECEXP (final_sequence, 0, 0))
      && INSN_FROM_TARGET_P (insn))
    return;

  /* If only calls can throw, and we have a frame pointer,
     save up adjustments until we see the CALL_INSN.  */
  if (!flag_asynchronous_unwind_tables && cfa.reg != STACK_POINTER_REGNUM)
    {
      if (CALL_P (insn) && !after_p)
        {
          /* Extract the size of the args from the CALL rtx itself.  */
          insn = PATTERN (insn);
          if (GET_CODE (insn) == PARALLEL)
            insn = XVECEXP (insn, 0, 0);
          if (GET_CODE (insn) == SET)
            insn = SET_SRC (insn);
          gcc_assert (GET_CODE (insn) == CALL);
          dwarf2out_args_size ("", INTVAL (XEXP (insn, 1)));
        }
      return;
    }

  if (CALL_P (insn) && !after_p)
    {
      if (!flag_asynchronous_unwind_tables)
        dwarf2out_args_size ("", args_size);
      return;
    }
  else if (BARRIER_P (insn))
    {
      /* Don't call compute_barrier_args_size () if the only
         BARRIER is at the end of function.  */
      if (barrier_args_size == NULL && next_nonnote_insn (insn))
        compute_barrier_args_size ();
      if (barrier_args_size == NULL)
        offset = 0;
      else
        {
          offset = barrier_args_size[INSN_UID (insn)];
          if (offset < 0)
            offset = 0;
        }

      offset -= args_size;
#ifndef STACK_GROWS_DOWNWARD
      offset = -offset;
#endif
    }
  else if (GET_CODE (PATTERN (insn)) == SET)
    offset = stack_adjust_offset (PATTERN (insn), args_size, 0);
  else if (GET_CODE (PATTERN (insn)) == PARALLEL
           || GET_CODE (PATTERN (insn)) == SEQUENCE)
    {
      /* There may be stack adjustments inside compound insns.  Search
         for them.  */
      for (offset = 0, i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
        if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
          offset += stack_adjust_offset (XVECEXP (PATTERN (insn), 0, i),
                                         args_size, offset);
    }
  else
    return;

  if (offset == 0)
    return;

  label = dwarf2out_cfi_label (false);
  dwarf2out_stack_adjust (offset, label);
}

/* We delay emitting a register save until either (a) we reach the end
   of the prologue or (b) the register is clobbered.  This clusters
   register saves so that there are fewer pc advances.  */

struct GTY(()) queued_reg_save {
  struct queued_reg_save *next;
  rtx reg;
  HOST_WIDE_INT cfa_offset;
  rtx saved_reg;
};

static GTY(()) struct queued_reg_save *queued_reg_saves;

/* The caller's ORIG_REG is saved in SAVED_IN_REG.  */
struct GTY(()) reg_saved_in_data {
  rtx orig_reg;
  rtx saved_in_reg;
};

/* A list of registers saved in other registers.
   The list intentionally has a small maximum capacity of 4; if your
   port needs more than that, you might consider implementing a
   more efficient data structure.  */
static GTY(()) struct reg_saved_in_data regs_saved_in_regs[4];
static GTY(()) size_t num_regs_saved_in_regs;

static const char *last_reg_save_label;

/* Add an entry to QUEUED_REG_SAVES saying that REG is now saved at
   SREG, or if SREG is NULL then it is saved at OFFSET to the CFA.  */

static void
queue_reg_save (const char *label, rtx reg, rtx sreg, HOST_WIDE_INT offset)
{
  struct queued_reg_save *q;

  /* Duplicates waste space, but it's also necessary to remove them
     for correctness, since the queue gets output in reverse
     order.  */
  for (q = queued_reg_saves; q != NULL; q = q->next)
    if (REGNO (q->reg) == REGNO (reg))
      break;

  if (q == NULL)
    {
      q = ggc_alloc_queued_reg_save ();
      q->next = queued_reg_saves;
      queued_reg_saves = q;
    }

  q->reg = reg;
  q->cfa_offset = offset;
  q->saved_reg = sreg;

  last_reg_save_label = label;
}

/* Output all the entries in QUEUED_REG_SAVES.  */

void
dwarf2out_flush_queued_reg_saves (void)
{
  struct queued_reg_save *q;

  for (q = queued_reg_saves; q; q = q->next)
    {
      size_t i;
      unsigned int reg, sreg;

      for (i = 0; i < num_regs_saved_in_regs; i++)
        if (REGNO (regs_saved_in_regs[i].orig_reg) == REGNO (q->reg))
          break;
      if (q->saved_reg && i == num_regs_saved_in_regs)
        {
          gcc_assert (i != ARRAY_SIZE (regs_saved_in_regs));
          num_regs_saved_in_regs++;
        }
      if (i != num_regs_saved_in_regs)
        {
          regs_saved_in_regs[i].orig_reg = q->reg;
          regs_saved_in_regs[i].saved_in_reg = q->saved_reg;
        }

      reg = DWARF_FRAME_REGNUM (REGNO (q->reg));
      if (q->saved_reg)
        sreg = DWARF_FRAME_REGNUM (REGNO (q->saved_reg));
      else
        sreg = INVALID_REGNUM;
      reg_save (last_reg_save_label, reg, sreg, q->cfa_offset);
    }

  queued_reg_saves = NULL;
  last_reg_save_label = NULL;
}

/* Does INSN clobber any register which QUEUED_REG_SAVES lists a saved
   location for?  Or, does it clobber a register which we've previously
   said that some other register is saved in, and for which we now
   have a new location for?  */

static bool
clobbers_queued_reg_save (const_rtx insn)
{
  struct queued_reg_save *q;

  for (q = queued_reg_saves; q; q = q->next)
    {
      size_t i;
      if (modified_in_p (q->reg, insn))
        return true;
      for (i = 0; i < num_regs_saved_in_regs; i++)
        if (REGNO (q->reg) == REGNO (regs_saved_in_regs[i].orig_reg)
            && modified_in_p (regs_saved_in_regs[i].saved_in_reg, insn))
          return true;
    }

  return false;
}

/* Entry point for saving the first register into the second.  */

void
dwarf2out_reg_save_reg (const char *label, rtx reg, rtx sreg)
{
  size_t i;
  unsigned int regno, sregno;

  for (i = 0; i < num_regs_saved_in_regs; i++)
    if (REGNO (regs_saved_in_regs[i].orig_reg) == REGNO (reg))
      break;
  if (i == num_regs_saved_in_regs)
    {
      gcc_assert (i != ARRAY_SIZE (regs_saved_in_regs));
      num_regs_saved_in_regs++;
    }
  regs_saved_in_regs[i].orig_reg = reg;
  regs_saved_in_regs[i].saved_in_reg = sreg;

  regno = DWARF_FRAME_REGNUM (REGNO (reg));
  sregno = DWARF_FRAME_REGNUM (REGNO (sreg));
  reg_save (label, regno, sregno, 0);
}

/* What register, if any, is currently saved in REG?  */

static rtx
reg_saved_in (rtx reg)
{
  unsigned int regn = REGNO (reg);
  size_t i;
  struct queued_reg_save *q;

  for (q = queued_reg_saves; q; q = q->next)
    if (q->saved_reg && regn == REGNO (q->saved_reg))
      return q->reg;

  for (i = 0; i < num_regs_saved_in_regs; i++)
    if (regs_saved_in_regs[i].saved_in_reg
        && regn == REGNO (regs_saved_in_regs[i].saved_in_reg))
      return regs_saved_in_regs[i].orig_reg;

  return NULL_RTX;
}


/* A temporary register holding an integral value used in adjusting SP
   or setting up the store_reg.  The "offset" field holds the integer
   value, not an offset.  */
static dw_cfa_location cfa_temp;

/* A subroutine of dwarf2out_frame_debug, process a REG_DEF_CFA note.  */

static void
dwarf2out_frame_debug_def_cfa (rtx pat, const char *label)
{
  memset (&cfa, 0, sizeof (cfa));

  switch (GET_CODE (pat))
    {
    case PLUS:
      cfa.reg = REGNO (XEXP (pat, 0));
      cfa.offset = INTVAL (XEXP (pat, 1));
      break;

    case REG:
      cfa.reg = REGNO (pat);
      break;

    case MEM:
      cfa.indirect = 1;
      pat = XEXP (pat, 0);
      if (GET_CODE (pat) == PLUS)
        {
          cfa.base_offset = INTVAL (XEXP (pat, 1));
          pat = XEXP (pat, 0);
        }
      cfa.reg = REGNO (pat);
      break;

    default:
      /* Recurse and define an expression.  */
      gcc_unreachable ();
    }

  def_cfa_1 (label, &cfa);
}

/* A subroutine of dwarf2out_frame_debug, process a REG_ADJUST_CFA note.  */

static void
dwarf2out_frame_debug_adjust_cfa (rtx pat, const char *label)
{
  rtx src, dest;

  gcc_assert (GET_CODE (pat) == SET);
  dest = XEXP (pat, 0);
  src = XEXP (pat, 1);

  switch (GET_CODE (src))
    {
    case PLUS:
      gcc_assert (REGNO (XEXP (src, 0)) == cfa.reg);
      cfa.offset -= INTVAL (XEXP (src, 1));
      break;

    case REG:
        break;

    default:
        gcc_unreachable ();
    }

  cfa.reg = REGNO (dest);
  gcc_assert (cfa.indirect == 0);

  def_cfa_1 (label, &cfa);
}

/* A subroutine of dwarf2out_frame_debug, process a REG_CFA_OFFSET note.  */

static void
dwarf2out_frame_debug_cfa_offset (rtx set, const char *label)
{
  HOST_WIDE_INT offset;
  rtx src, addr, span;

  src = XEXP (set, 1);
  addr = XEXP (set, 0);
  gcc_assert (MEM_P (addr));
  addr = XEXP (addr, 0);

  /* As documented, only consider extremely simple addresses.  */
  switch (GET_CODE (addr))
    {
    case REG:
      gcc_assert (REGNO (addr) == cfa.reg);
      offset = -cfa.offset;
      break;
    case PLUS:
      gcc_assert (REGNO (XEXP (addr, 0)) == cfa.reg);
      offset = INTVAL (XEXP (addr, 1)) - cfa.offset;
      break;
    default:
      gcc_unreachable ();
    }

  span = targetm.dwarf_register_span (src);

  /* ??? We'd like to use queue_reg_save, but we need to come up with
     a different flushing heuristic for epilogues.  */
  if (!span)
    reg_save (label, DWARF_FRAME_REGNUM (REGNO (src)), INVALID_REGNUM, offset);
  else
    {
      /* We have a PARALLEL describing where the contents of SRC live.
         Queue register saves for each piece of the PARALLEL.  */
      int par_index;
      int limit;
      HOST_WIDE_INT span_offset = offset;

      gcc_assert (GET_CODE (span) == PARALLEL);

      limit = XVECLEN (span, 0);
      for (par_index = 0; par_index < limit; par_index++)
        {
          rtx elem = XVECEXP (span, 0, par_index);

          reg_save (label, DWARF_FRAME_REGNUM (REGNO (elem)),
                    INVALID_REGNUM, span_offset);
          span_offset += GET_MODE_SIZE (GET_MODE (elem));
        }
    }
}

/* A subroutine of dwarf2out_frame_debug, process a REG_CFA_REGISTER note.  */

static void
dwarf2out_frame_debug_cfa_register (rtx set, const char *label)
{
  rtx src, dest;
  unsigned sregno, dregno;

  src = XEXP (set, 1);
  dest = XEXP (set, 0);

  if (src == pc_rtx)
    sregno = DWARF_FRAME_RETURN_COLUMN;
  else
    sregno = DWARF_FRAME_REGNUM (REGNO (src));

  dregno = DWARF_FRAME_REGNUM (REGNO (dest));

  /* ??? We'd like to use queue_reg_save, but we need to come up with
     a different flushing heuristic for epilogues.  */
  reg_save (label, sregno, dregno, 0);
}

/* A subroutine of dwarf2out_frame_debug, process a REG_CFA_EXPRESSION note. */

static void
dwarf2out_frame_debug_cfa_expression (rtx set, const char *label)
{
  rtx src, dest, span;
  dw_cfi_ref cfi = new_cfi ();

  dest = SET_DEST (set);
  src = SET_SRC (set);

  gcc_assert (REG_P (src));
  gcc_assert (MEM_P (dest));

  span = targetm.dwarf_register_span (src);
  gcc_assert (!span);

  cfi->dw_cfi_opc = DW_CFA_expression;
  cfi->dw_cfi_oprnd1.dw_cfi_reg_num = DWARF_FRAME_REGNUM (REGNO (src));
  cfi->dw_cfi_oprnd2.dw_cfi_loc
    = mem_loc_descriptor (XEXP (dest, 0), GET_MODE (dest),
                          VAR_INIT_STATUS_INITIALIZED);

  /* ??? We'd like to use queue_reg_save, were the interface different,
     and, as above, we could manage flushing for epilogues.  */
  add_fde_cfi (label, cfi);
}

/* A subroutine of dwarf2out_frame_debug, process a REG_CFA_RESTORE note.  */

static void
dwarf2out_frame_debug_cfa_restore (rtx reg, const char *label)
{
  dw_cfi_ref cfi = new_cfi ();
  unsigned int regno = DWARF_FRAME_REGNUM (REGNO (reg));

  cfi->dw_cfi_opc = (regno & ~0x3f ? DW_CFA_restore_extended : DW_CFA_restore);
  cfi->dw_cfi_oprnd1.dw_cfi_reg_num = regno;

  add_fde_cfi (label, cfi);
}

/* Record call frame debugging information for an expression EXPR,
   which either sets SP or FP (adjusting how we calculate the frame
   address) or saves a register to the stack or another register.
   LABEL indicates the address of EXPR.

   This function encodes a state machine mapping rtxes to actions on
   cfa, cfa_store, and cfa_temp.reg.  We describe these rules so
   users need not read the source code.

  The High-Level Picture

  Changes in the register we use to calculate the CFA: Currently we
  assume that if you copy the CFA register into another register, we
  should take the other one as the new CFA register; this seems to
  work pretty well.  If it's wrong for some target, it's simple
  enough not to set RTX_FRAME_RELATED_P on the insn in question.

  Changes in the register we use for saving registers to the stack:
  This is usually SP, but not always.  Again, we deduce that if you
  copy SP into another register (and SP is not the CFA register),
  then the new register is the one we will be using for register
  saves.  This also seems to work.

  Register saves: There's not much guesswork about this one; if
  RTX_FRAME_RELATED_P is set on an insn which modifies memory, it's a
  register save, and the register used to calculate the destination
  had better be the one we think we're using for this purpose.
  It's also assumed that a copy from a call-saved register to another
  register is saving that register if RTX_FRAME_RELATED_P is set on
  that instruction.  If the copy is from a call-saved register to
  the *same* register, that means that the register is now the same
  value as in the caller.

  Except: If the register being saved is the CFA register, and the
  offset is nonzero, we are saving the CFA, so we assume we have to
  use DW_CFA_def_cfa_expression.  If the offset is 0, we assume that
  the intent is to save the value of SP from the previous frame.

  In addition, if a register has previously been saved to a different
  register,

  Invariants / Summaries of Rules

  cfa          current rule for calculating the CFA.  It usually
               consists of a register and an offset.
  cfa_store    register used by prologue code to save things to the stack
               cfa_store.offset is the offset from the value of
               cfa_store.reg to the actual CFA
  cfa_temp     register holding an integral value.  cfa_temp.offset
               stores the value, which will be used to adjust the
               stack pointer.  cfa_temp is also used like cfa_store,
               to track stores to the stack via fp or a temp reg.

  Rules  1- 4: Setting a register's value to cfa.reg or an expression
               with cfa.reg as the first operand changes the cfa.reg and its
               cfa.offset.  Rule 1 and 4 also set cfa_temp.reg and
               cfa_temp.offset.

  Rules  6- 9: Set a non-cfa.reg register value to a constant or an
               expression yielding a constant.  This sets cfa_temp.reg
               and cfa_temp.offset.

  Rule 5:      Create a new register cfa_store used to save items to the
               stack.

  Rules 10-14: Save a register to the stack.  Define offset as the
               difference of the original location and cfa_store's
               location (or cfa_temp's location if cfa_temp is used).

  Rules 16-20: If AND operation happens on sp in prologue, we assume
               stack is realigned.  We will use a group of DW_OP_XXX
               expressions to represent the location of the stored
               register instead of CFA+offset.

  The Rules

  "{a,b}" indicates a choice of a xor b.
  "<reg>:cfa.reg" indicates that <reg> must equal cfa.reg.

  Rule 1:
  (set <reg1> <reg2>:cfa.reg)
  effects: cfa.reg = <reg1>
           cfa.offset unchanged
           cfa_temp.reg = <reg1>
           cfa_temp.offset = cfa.offset

  Rule 2:
  (set sp ({minus,plus,losum} {sp,fp}:cfa.reg
                              {<const_int>,<reg>:cfa_temp.reg}))
  effects: cfa.reg = sp if fp used
           cfa.offset += {+/- <const_int>, cfa_temp.offset} if cfa.reg==sp
           cfa_store.offset += {+/- <const_int>, cfa_temp.offset}
             if cfa_store.reg==sp

  Rule 3:
  (set fp ({minus,plus,losum} <reg>:cfa.reg <const_int>))
  effects: cfa.reg = fp
           cfa_offset += +/- <const_int>

  Rule 4:
  (set <reg1> ({plus,losum} <reg2>:cfa.reg <const_int>))
  constraints: <reg1> != fp
               <reg1> != sp
  effects: cfa.reg = <reg1>
           cfa_temp.reg = <reg1>
           cfa_temp.offset = cfa.offset

  Rule 5:
  (set <reg1> (plus <reg2>:cfa_temp.reg sp:cfa.reg))
  constraints: <reg1> != fp
               <reg1> != sp
  effects: cfa_store.reg = <reg1>
           cfa_store.offset = cfa.offset - cfa_temp.offset

  Rule 6:
  (set <reg> <const_int>)
  effects: cfa_temp.reg = <reg>
           cfa_temp.offset = <const_int>

  Rule 7:
  (set <reg1>:cfa_temp.reg (ior <reg2>:cfa_temp.reg <const_int>))
  effects: cfa_temp.reg = <reg1>
           cfa_temp.offset |= <const_int>

  Rule 8:
  (set <reg> (high <exp>))
  effects: none

  Rule 9:
  (set <reg> (lo_sum <exp> <const_int>))
  effects: cfa_temp.reg = <reg>
           cfa_temp.offset = <const_int>

  Rule 10:
  (set (mem (pre_modify sp:cfa_store (???? <reg1> <const_int>))) <reg2>)
  effects: cfa_store.offset -= <const_int>
           cfa.offset = cfa_store.offset if cfa.reg == sp
           cfa.reg = sp
           cfa.base_offset = -cfa_store.offset

  Rule 11:
  (set (mem ({pre_inc,pre_dec} sp:cfa_store.reg)) <reg>)
  effects: cfa_store.offset += -/+ mode_size(mem)
           cfa.offset = cfa_store.offset if cfa.reg == sp
           cfa.reg = sp
           cfa.base_offset = -cfa_store.offset

  Rule 12:
  (set (mem ({minus,plus,losum} <reg1>:{cfa_store,cfa_temp} <const_int>))

       <reg2>)
  effects: cfa.reg = <reg1>
           cfa.base_offset = -/+ <const_int> - {cfa_store,cfa_temp}.offset

  Rule 13:
  (set (mem <reg1>:{cfa_store,cfa_temp}) <reg2>)
  effects: cfa.reg = <reg1>
           cfa.base_offset = -{cfa_store,cfa_temp}.offset

  Rule 14:
  (set (mem (postinc <reg1>:cfa_temp <const_int>)) <reg2>)
  effects: cfa.reg = <reg1>
           cfa.base_offset = -cfa_temp.offset
           cfa_temp.offset -= mode_size(mem)

  Rule 15:
  (set <reg> {unspec, unspec_volatile})
  effects: target-dependent

  Rule 16:
  (set sp (and: sp <const_int>))
  constraints: cfa_store.reg == sp
  effects: current_fde.stack_realign = 1
           cfa_store.offset = 0
           fde->drap_reg = cfa.reg if cfa.reg != sp and cfa.reg != fp

  Rule 17:
  (set (mem ({pre_inc, pre_dec} sp)) (mem (plus (cfa.reg) (const_int))))
  effects: cfa_store.offset += -/+ mode_size(mem)

  Rule 18:
  (set (mem ({pre_inc, pre_dec} sp)) fp)
  constraints: fde->stack_realign == 1
  effects: cfa_store.offset = 0
           cfa.reg != HARD_FRAME_POINTER_REGNUM

  Rule 19:
  (set (mem ({pre_inc, pre_dec} sp)) cfa.reg)
  constraints: fde->stack_realign == 1
               && cfa.offset == 0
               && cfa.indirect == 0
               && cfa.reg != HARD_FRAME_POINTER_REGNUM
  effects: Use DW_CFA_def_cfa_expression to define cfa
           cfa.reg == fde->drap_reg  */

static void
dwarf2out_frame_debug_expr (rtx expr, const char *label)
{
  rtx src, dest, span;
  HOST_WIDE_INT offset;
  dw_fde_ref fde;

  /* If RTX_FRAME_RELATED_P is set on a PARALLEL, process each member of
     the PARALLEL independently. The first element is always processed if
     it is a SET. This is for backward compatibility.   Other elements
     are processed only if they are SETs and the RTX_FRAME_RELATED_P
     flag is set in them.  */
  if (GET_CODE (expr) == PARALLEL || GET_CODE (expr) == SEQUENCE)
    {
      int par_index;
      int limit = XVECLEN (expr, 0);
      rtx elem;

      /* PARALLELs have strict read-modify-write semantics, so we
         ought to evaluate every rvalue before changing any lvalue.
         It's cumbersome to do that in general, but there's an
         easy approximation that is enough for all current users:
         handle register saves before register assignments.  */
      if (GET_CODE (expr) == PARALLEL)
        for (par_index = 0; par_index < limit; par_index++)
          {
            elem = XVECEXP (expr, 0, par_index);
            if (GET_CODE (elem) == SET
                && MEM_P (SET_DEST (elem))
                && (RTX_FRAME_RELATED_P (elem) || par_index == 0))
              dwarf2out_frame_debug_expr (elem, label);
          }

      for (par_index = 0; par_index < limit; par_index++)
        {
          elem = XVECEXP (expr, 0, par_index);
          if (GET_CODE (elem) == SET
              && (!MEM_P (SET_DEST (elem)) || GET_CODE (expr) == SEQUENCE)
              && (RTX_FRAME_RELATED_P (elem) || par_index == 0))
            dwarf2out_frame_debug_expr (elem, label);
          else if (GET_CODE (elem) == SET
                   && par_index != 0
                   && !RTX_FRAME_RELATED_P (elem))
            {
              /* Stack adjustment combining might combine some post-prologue
                 stack adjustment into a prologue stack adjustment.  */
              HOST_WIDE_INT offset = stack_adjust_offset (elem, args_size, 0);

              if (offset != 0)
                dwarf2out_stack_adjust (offset, label);
            }
        }
      return;
    }

  gcc_assert (GET_CODE (expr) == SET);

  src = SET_SRC (expr);
  dest = SET_DEST (expr);

  if (REG_P (src))
    {
      rtx rsi = reg_saved_in (src);
      if (rsi)
        src = rsi;
    }

  fde = current_fde ();

  switch (GET_CODE (dest))
    {
    case REG:
      switch (GET_CODE (src))
        {
          /* Setting FP from SP.  */
        case REG:
          if (cfa.reg == (unsigned) REGNO (src))
            {
              /* Rule 1 */
              /* Update the CFA rule wrt SP or FP.  Make sure src is
                 relative to the current CFA register.

                 We used to require that dest be either SP or FP, but the
                 ARM copies SP to a temporary register, and from there to
                 FP.  So we just rely on the backends to only set
                 RTX_FRAME_RELATED_P on appropriate insns.  */
              cfa.reg = REGNO (dest);
              cfa_temp.reg = cfa.reg;
              cfa_temp.offset = cfa.offset;
            }
          else
            {
              /* Saving a register in a register.  */
              gcc_assert (!fixed_regs [REGNO (dest)]
                          /* For the SPARC and its register window.  */
                          || (DWARF_FRAME_REGNUM (REGNO (src))
                              == DWARF_FRAME_RETURN_COLUMN));

              /* After stack is aligned, we can only save SP in FP
                 if drap register is used.  In this case, we have
                 to restore stack pointer with the CFA value and we
                 don't generate this DWARF information.  */
              if (fde
                  && fde->stack_realign
                  && REGNO (src) == STACK_POINTER_REGNUM)
                gcc_assert (REGNO (dest) == HARD_FRAME_POINTER_REGNUM
                            && fde->drap_reg != INVALID_REGNUM
                            && cfa.reg != REGNO (src));
              else
                queue_reg_save (label, src, dest, 0);
            }
          break;

        case PLUS:
        case MINUS:
        case LO_SUM:
          if (dest == stack_pointer_rtx)
            {
              /* Rule 2 */
              /* Adjusting SP.  */
              switch (GET_CODE (XEXP (src, 1)))
                {
                case CONST_INT:
                  offset = INTVAL (XEXP (src, 1));
                  break;
                case REG:
                  gcc_assert ((unsigned) REGNO (XEXP (src, 1))
                              == cfa_temp.reg);
                  offset = cfa_temp.offset;
                  break;
                default:
                  gcc_unreachable ();
                }

              if (XEXP (src, 0) == hard_frame_pointer_rtx)
                {
                  /* Restoring SP from FP in the epilogue.  */
                  gcc_assert (cfa.reg == (unsigned) HARD_FRAME_POINTER_REGNUM);
                  cfa.reg = STACK_POINTER_REGNUM;
                }
              else if (GET_CODE (src) == LO_SUM)
                /* Assume we've set the source reg of the LO_SUM from sp.  */
                ;
              else
                gcc_assert (XEXP (src, 0) == stack_pointer_rtx);

              if (GET_CODE (src) != MINUS)
                offset = -offset;
              if (cfa.reg == STACK_POINTER_REGNUM)
                cfa.offset += offset;
              if (cfa_store.reg == STACK_POINTER_REGNUM)
                cfa_store.offset += offset;
            }
          else if (dest == hard_frame_pointer_rtx)
            {
              /* Rule 3 */
              /* Either setting the FP from an offset of the SP,
                 or adjusting the FP */
              gcc_assert (frame_pointer_needed);

              gcc_assert (REG_P (XEXP (src, 0))
                          && (unsigned) REGNO (XEXP (src, 0)) == cfa.reg
                          && CONST_INT_P (XEXP (src, 1)));
              offset = INTVAL (XEXP (src, 1));
              if (GET_CODE (src) != MINUS)
                offset = -offset;
              cfa.offset += offset;
              cfa.reg = HARD_FRAME_POINTER_REGNUM;
            }
          else
            {
              gcc_assert (GET_CODE (src) != MINUS);

              /* Rule 4 */
              if (REG_P (XEXP (src, 0))
                  && REGNO (XEXP (src, 0)) == cfa.reg
                  && CONST_INT_P (XEXP (src, 1)))
                {
                  /* Setting a temporary CFA register that will be copied
                     into the FP later on.  */
                  offset = - INTVAL (XEXP (src, 1));
                  cfa.offset += offset;
                  cfa.reg = REGNO (dest);
                  /* Or used to save regs to the stack.  */
                  cfa_temp.reg = cfa.reg;
                  cfa_temp.offset = cfa.offset;
                }

              /* Rule 5 */
              else if (REG_P (XEXP (src, 0))
                       && REGNO (XEXP (src, 0)) == cfa_temp.reg
                       && XEXP (src, 1) == stack_pointer_rtx)
                {
                  /* Setting a scratch register that we will use instead
                     of SP for saving registers to the stack.  */
                  gcc_assert (cfa.reg == STACK_POINTER_REGNUM);
                  cfa_store.reg = REGNO (dest);
                  cfa_store.offset = cfa.offset - cfa_temp.offset;
                }

              /* Rule 9 */
              else if (GET_CODE (src) == LO_SUM
                       && CONST_INT_P (XEXP (src, 1)))
                {
                  cfa_temp.reg = REGNO (dest);
                  cfa_temp.offset = INTVAL (XEXP (src, 1));
                }
              else
                gcc_unreachable ();
            }
          break;

          /* Rule 6 */
        case CONST_INT:
          cfa_temp.reg = REGNO (dest);
          cfa_temp.offset = INTVAL (src);
          break;

          /* Rule 7 */
        case IOR:
          gcc_assert (REG_P (XEXP (src, 0))
                      && (unsigned) REGNO (XEXP (src, 0)) == cfa_temp.reg
                      && CONST_INT_P (XEXP (src, 1)));

          if ((unsigned) REGNO (dest) != cfa_temp.reg)
            cfa_temp.reg = REGNO (dest);
          cfa_temp.offset |= INTVAL (XEXP (src, 1));
          break;

          /* Skip over HIGH, assuming it will be followed by a LO_SUM,
             which will fill in all of the bits.  */
          /* Rule 8 */
        case HIGH:
          break;

          /* Rule 15 */
        case UNSPEC:
        case UNSPEC_VOLATILE:
          gcc_assert (targetm.dwarf_handle_frame_unspec);
          targetm.dwarf_handle_frame_unspec (label, expr, XINT (src, 1));
          return;

          /* Rule 16 */
        case AND:
          /* If this AND operation happens on stack pointer in prologue,
             we assume the stack is realigned and we extract the
             alignment.  */
          if (fde && XEXP (src, 0) == stack_pointer_rtx)
            {
              /* We interpret reg_save differently with stack_realign set.
                 Thus we must flush whatever we have queued first.  */
              dwarf2out_flush_queued_reg_saves ();

              gcc_assert (cfa_store.reg == REGNO (XEXP (src, 0)));
              fde->stack_realign = 1;
              fde->stack_realignment = INTVAL (XEXP (src, 1));
              cfa_store.offset = 0;

              if (cfa.reg != STACK_POINTER_REGNUM
                  && cfa.reg != HARD_FRAME_POINTER_REGNUM)
                fde->drap_reg = cfa.reg;
            }
          return;

        default:
          gcc_unreachable ();
        }

      def_cfa_1 (label, &cfa);
      break;

    case MEM:

      /* Saving a register to the stack.  Make sure dest is relative to the
         CFA register.  */
      switch (GET_CODE (XEXP (dest, 0)))
        {
          /* Rule 10 */
          /* With a push.  */
        case PRE_MODIFY:
          /* We can't handle variable size modifications.  */
          gcc_assert (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
                      == CONST_INT);
          offset = -INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1));

          gcc_assert (REGNO (XEXP (XEXP (dest, 0), 0)) == STACK_POINTER_REGNUM
                      && cfa_store.reg == STACK_POINTER_REGNUM);

          cfa_store.offset += offset;
          if (cfa.reg == STACK_POINTER_REGNUM)
            cfa.offset = cfa_store.offset;

          offset = -cfa_store.offset;
          break;

          /* Rule 11 */
        case PRE_INC:
        case PRE_DEC:
          offset = GET_MODE_SIZE (GET_MODE (dest));
          if (GET_CODE (XEXP (dest, 0)) == PRE_INC)
            offset = -offset;

          gcc_assert ((REGNO (XEXP (XEXP (dest, 0), 0))
                       == STACK_POINTER_REGNUM)
                      && cfa_store.reg == STACK_POINTER_REGNUM);

          cfa_store.offset += offset;

          /* Rule 18: If stack is aligned, we will use FP as a
             reference to represent the address of the stored
             regiser.  */
          if (fde
              && fde->stack_realign
              && src == hard_frame_pointer_rtx)
            {
              gcc_assert (cfa.reg != HARD_FRAME_POINTER_REGNUM);
              cfa_store.offset = 0;
            }

          if (cfa.reg == STACK_POINTER_REGNUM)
            cfa.offset = cfa_store.offset;

          offset = -cfa_store.offset;
          break;

          /* Rule 12 */
          /* With an offset.  */
        case PLUS:
        case MINUS:
        case LO_SUM:
          {
            int regno;

            gcc_assert (CONST_INT_P (XEXP (XEXP (dest, 0), 1))
                        && REG_P (XEXP (XEXP (dest, 0), 0)));
            offset = INTVAL (XEXP (XEXP (dest, 0), 1));
            if (GET_CODE (XEXP (dest, 0)) == MINUS)
              offset = -offset;

            regno = REGNO (XEXP (XEXP (dest, 0), 0));

            if (cfa.reg == (unsigned) regno)
              offset -= cfa.offset;
            else if (cfa_store.reg == (unsigned) regno)
              offset -= cfa_store.offset;
            else
              {
                gcc_assert (cfa_temp.reg == (unsigned) regno);
                offset -= cfa_temp.offset;
              }
          }
          break;

          /* Rule 13 */
          /* Without an offset.  */
        case REG:
          {
            int regno = REGNO (XEXP (dest, 0));

            if (cfa.reg == (unsigned) regno)
              offset = -cfa.offset;
            else if (cfa_store.reg == (unsigned) regno)
              offset = -cfa_store.offset;
            else
              {
                gcc_assert (cfa_temp.reg == (unsigned) regno);
                offset = -cfa_temp.offset;
              }
          }
          break;

          /* Rule 14 */
        case POST_INC:
          gcc_assert (cfa_temp.reg
                      == (unsigned) REGNO (XEXP (XEXP (dest, 0), 0)));
          offset = -cfa_temp.offset;
          cfa_temp.offset -= GET_MODE_SIZE (GET_MODE (dest));
          break;

        default:
          gcc_unreachable ();
        }

        /* Rule 17 */
        /* If the source operand of this MEM operation is not a
           register, basically the source is return address.  Here
           we only care how much stack grew and we don't save it.  */
      if (!REG_P (src))
        break;

      if (REGNO (src) != STACK_POINTER_REGNUM
          && REGNO (src) != HARD_FRAME_POINTER_REGNUM
          && (unsigned) REGNO (src) == cfa.reg)
        {
          /* We're storing the current CFA reg into the stack.  */

          if (cfa.offset == 0)
            {
              /* Rule 19 */
              /* If stack is aligned, putting CFA reg into stack means
                 we can no longer use reg + offset to represent CFA.
                 Here we use DW_CFA_def_cfa_expression instead.  The
                 result of this expression equals to the original CFA
                 value.  */
              if (fde
                  && fde->stack_realign
                  && cfa.indirect == 0
                  && cfa.reg != HARD_FRAME_POINTER_REGNUM)
                {
                  dw_cfa_location cfa_exp;

                  gcc_assert (fde->drap_reg == cfa.reg);

                  cfa_exp.indirect = 1;
                  cfa_exp.reg = HARD_FRAME_POINTER_REGNUM;
                  cfa_exp.base_offset = offset;
                  cfa_exp.offset = 0;

                  fde->drap_reg_saved = 1;

                  def_cfa_1 (label, &cfa_exp);
                  break;
                }

              /* If the source register is exactly the CFA, assume
                 we're saving SP like any other register; this happens
                 on the ARM.  */
              def_cfa_1 (label, &cfa);
              queue_reg_save (label, stack_pointer_rtx, NULL_RTX, offset);
              break;
            }
          else
            {
              /* Otherwise, we'll need to look in the stack to
                 calculate the CFA.  */
              rtx x = XEXP (dest, 0);

              if (!REG_P (x))
                x = XEXP (x, 0);
              gcc_assert (REG_P (x));

              cfa.reg = REGNO (x);
              cfa.base_offset = offset;
              cfa.indirect = 1;
              def_cfa_1 (label, &cfa);
              break;
            }
        }

      def_cfa_1 (label, &cfa);
      {
        span = targetm.dwarf_register_span (src);

        if (!span)
          queue_reg_save (label, src, NULL_RTX, offset);
        else
          {
            /* We have a PARALLEL describing where the contents of SRC
               live.  Queue register saves for each piece of the
               PARALLEL.  */
            int par_index;
            int limit;
            HOST_WIDE_INT span_offset = offset;

            gcc_assert (GET_CODE (span) == PARALLEL);

            limit = XVECLEN (span, 0);
            for (par_index = 0; par_index < limit; par_index++)
              {
                rtx elem = XVECEXP (span, 0, par_index);

                queue_reg_save (label, elem, NULL_RTX, span_offset);
                span_offset += GET_MODE_SIZE (GET_MODE (elem));
              }
          }
      }
      break;

    default:
      gcc_unreachable ();
    }
}

/* Record call frame debugging information for INSN, which either
   sets SP or FP (adjusting how we calculate the frame address) or saves a
   register to the stack.  If INSN is NULL_RTX, initialize our state.

   If AFTER_P is false, we're being called before the insn is emitted,
   otherwise after.  Call instructions get invoked twice.  */

void
dwarf2out_frame_debug (rtx insn, bool after_p)
{
  const char *label;
  rtx note, n;
  bool handled_one = false;

  if (insn == NULL_RTX)
    {
      size_t i;

      /* Flush any queued register saves.  */
      dwarf2out_flush_queued_reg_saves ();

      /* Set up state for generating call frame debug info.  */
      lookup_cfa (&cfa);
      gcc_assert (cfa.reg
                  == (unsigned long)DWARF_FRAME_REGNUM (STACK_POINTER_REGNUM));

      cfa.reg = STACK_POINTER_REGNUM;
      cfa_store = cfa;
      cfa_temp.reg = -1;
      cfa_temp.offset = 0;

      for (i = 0; i < num_regs_saved_in_regs; i++)
        {
          regs_saved_in_regs[i].orig_reg = NULL_RTX;
          regs_saved_in_regs[i].saved_in_reg = NULL_RTX;
        }
      num_regs_saved_in_regs = 0;

      if (barrier_args_size)
        {
          XDELETEVEC (barrier_args_size);
          barrier_args_size = NULL;
        }
      return;
    }

  if (!NONJUMP_INSN_P (insn) || clobbers_queued_reg_save (insn))
    dwarf2out_flush_queued_reg_saves ();

  if (!RTX_FRAME_RELATED_P (insn))
    {
      /* ??? This should be done unconditionally since stack adjustments
         matter if the stack pointer is not the CFA register anymore but
         is still used to save registers.  */
      if (!ACCUMULATE_OUTGOING_ARGS)
        dwarf2out_notice_stack_adjust (insn, after_p);
      return;
    }

  label = dwarf2out_cfi_label (false);
  any_cfis_emitted = false;

  for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
    switch (REG_NOTE_KIND (note))
      {
      case REG_FRAME_RELATED_EXPR:
        insn = XEXP (note, 0);
        goto found;

      case REG_CFA_DEF_CFA:
        dwarf2out_frame_debug_def_cfa (XEXP (note, 0), label);
        handled_one = true;
        break;

      case REG_CFA_ADJUST_CFA:
        n = XEXP (note, 0);
        if (n == NULL)
          {
            n = PATTERN (insn);
            if (GET_CODE (n) == PARALLEL)
              n = XVECEXP (n, 0, 0);
          }
        dwarf2out_frame_debug_adjust_cfa (n, label);
        handled_one = true;
        break;

      case REG_CFA_OFFSET:
        n = XEXP (note, 0);
        if (n == NULL)
          n = single_set (insn);
        dwarf2out_frame_debug_cfa_offset (n, label);
        handled_one = true;
        break;

      case REG_CFA_REGISTER:
        n = XEXP (note, 0);
        if (n == NULL)
          {
            n = PATTERN (insn);
            if (GET_CODE (n) == PARALLEL)
              n = XVECEXP (n, 0, 0);
          }
        dwarf2out_frame_debug_cfa_register (n, label);
        handled_one = true;
        break;

      case REG_CFA_EXPRESSION:
        n = XEXP (note, 0);
        if (n == NULL)
          n = single_set (insn);
        dwarf2out_frame_debug_cfa_expression (n, label);
        handled_one = true;
        break;

      case REG_CFA_RESTORE:
        n = XEXP (note, 0);
        if (n == NULL)
          {
            n = PATTERN (insn);
            if (GET_CODE (n) == PARALLEL)
              n = XVECEXP (n, 0, 0);
            n = XEXP (n, 0);
          }
        dwarf2out_frame_debug_cfa_restore (n, label);
        handled_one = true;
        break;

      case REG_CFA_SET_VDRAP:
        n = XEXP (note, 0);
        if (REG_P (n))
          {
            dw_fde_ref fde = current_fde ();
            if (fde)
              {
                gcc_assert (fde->vdrap_reg == INVALID_REGNUM);
                if (REG_P (n))
                  fde->vdrap_reg = REGNO (n);
              }
          }
        handled_one = true;
        break;

      default:
        break;
      }
  if (handled_one)
    {
      if (any_cfis_emitted)
        dwarf2out_flush_queued_reg_saves ();
      return;
    }

  insn = PATTERN (insn);
 found:
  dwarf2out_frame_debug_expr (insn, label);

  /* Check again.  A parallel can save and update the same register.
     We could probably check just once, here, but this is safer than
     removing the check above.  */
  if (any_cfis_emitted || clobbers_queued_reg_save (insn))
    dwarf2out_flush_queued_reg_saves ();
}

/* Determine if we need to save and restore CFI information around this
   epilogue.  If SIBCALL is true, then this is a sibcall epilogue.  If
   we do need to save/restore, then emit the save now, and insert a
   NOTE_INSN_CFA_RESTORE_STATE at the appropriate place in the stream.  */

void
dwarf2out_cfi_begin_epilogue (rtx insn)
{
  bool saw_frp = false;
  rtx i;

  /* Scan forward to the return insn, noticing if there are possible
     frame related insns.  */
  for (i = NEXT_INSN (insn); i ; i = NEXT_INSN (i))
    {
      if (!INSN_P (i))
        continue;

      /* Look for both regular and sibcalls to end the block.  */
      if (returnjump_p (i))
        break;
      if (CALL_P (i) && SIBLING_CALL_P (i))
        break;

      if (GET_CODE (PATTERN (i)) == SEQUENCE)
        {
          int idx;
          rtx seq = PATTERN (i);

          if (returnjump_p (XVECEXP (seq, 0, 0)))
            break;
          if (CALL_P (XVECEXP (seq, 0, 0))
              && SIBLING_CALL_P (XVECEXP (seq, 0, 0)))
            break;

          for (idx = 0; idx < XVECLEN (seq, 0); idx++)
            if (RTX_FRAME_RELATED_P (XVECEXP (seq, 0, idx)))
              saw_frp = true;
        }

      if (RTX_FRAME_RELATED_P (i))
        saw_frp = true;
    }

  /* If the port doesn't emit epilogue unwind info, we don't need a
     save/restore pair.  */
  if (!saw_frp)
    return;

  /* Otherwise, search forward to see if the return insn was the last
     basic block of the function.  If so, we don't need save/restore.  */
  gcc_assert (i != NULL);
  i = next_real_insn (i);
  if (i == NULL)
    return;

  /* Insert the restore before that next real insn in the stream, and before
     a potential NOTE_INSN_EPILOGUE_BEG -- we do need these notes to be
     properly nested.  This should be after any label or alignment.  This
     will be pushed into the CFI stream by the function below.  */
  while (1)
    {
      rtx p = PREV_INSN (i);
      if (!NOTE_P (p))
        break;
      if (NOTE_KIND (p) == NOTE_INSN_BASIC_BLOCK)
        break;
      i = p;
    }
  emit_note_before (NOTE_INSN_CFA_RESTORE_STATE, i);

  emit_cfa_remember = true;

  /* And emulate the state save.  */
  gcc_assert (!cfa_remember.in_use);
  cfa_remember = cfa;
  cfa_remember.in_use = 1;
}

/* A "subroutine" of dwarf2out_cfi_begin_epilogue.  Emit the restore
   required.  */

void
dwarf2out_frame_debug_restore_state (void)
{
  dw_cfi_ref cfi = new_cfi ();
  const char *label = dwarf2out_cfi_label (false);

  cfi->dw_cfi_opc = DW_CFA_restore_state;
  add_fde_cfi (label, cfi);

  gcc_assert (cfa_remember.in_use);
  cfa = cfa_remember;
  cfa_remember.in_use = 0;
}

/* Describe for the GTY machinery what parts of dw_cfi_oprnd1 are used.  */
static enum dw_cfi_oprnd_type dw_cfi_oprnd1_desc
 (enum dwarf_call_frame_info cfi);

static enum dw_cfi_oprnd_type
dw_cfi_oprnd1_desc (enum dwarf_call_frame_info cfi)
{
  switch (cfi)
    {
    case DW_CFA_nop:
    case DW_CFA_GNU_window_save:
    case DW_CFA_remember_state:
    case DW_CFA_restore_state:
      return dw_cfi_oprnd_unused;

    case DW_CFA_set_loc:
    case DW_CFA_advance_loc1:
    case DW_CFA_advance_loc2:
    case DW_CFA_advance_loc4:
    case DW_CFA_MIPS_advance_loc8:
      return dw_cfi_oprnd_addr;

    case DW_CFA_offset:
    case DW_CFA_offset_extended:
    case DW_CFA_def_cfa:
    case DW_CFA_offset_extended_sf:
    case DW_CFA_def_cfa_sf:
    case DW_CFA_restore:
    case DW_CFA_restore_extended:
    case DW_CFA_undefined:
    case DW_CFA_same_value:
    case DW_CFA_def_cfa_register:
    case DW_CFA_register:
    case DW_CFA_expression:
      return dw_cfi_oprnd_reg_num;

    case DW_CFA_def_cfa_offset:
    case DW_CFA_GNU_args_size:
    case DW_CFA_def_cfa_offset_sf:
      return dw_cfi_oprnd_offset;

    case DW_CFA_def_cfa_expression:
      return dw_cfi_oprnd_loc;

    default:
      gcc_unreachable ();
    }
}

/* Describe for the GTY machinery what parts of dw_cfi_oprnd2 are used.  */
static enum dw_cfi_oprnd_type dw_cfi_oprnd2_desc
 (enum dwarf_call_frame_info cfi);

static enum dw_cfi_oprnd_type
dw_cfi_oprnd2_desc (enum dwarf_call_frame_info cfi)
{
  switch (cfi)
    {
    case DW_CFA_def_cfa:
    case DW_CFA_def_cfa_sf:
    case DW_CFA_offset:
    case DW_CFA_offset_extended_sf:
    case DW_CFA_offset_extended:
      return dw_cfi_oprnd_offset;

    case DW_CFA_register:
      return dw_cfi_oprnd_reg_num;

    case DW_CFA_expression:
      return dw_cfi_oprnd_loc;

    default:
      return dw_cfi_oprnd_unused;
    }
}

/* Switch [BACK] to eh_frame_section.  If we don't have an eh_frame_section,
   switch to the data section instead, and write out a synthetic start label
   for collect2 the first time around.  */

static void
switch_to_eh_frame_section (bool back)
{
  tree label;

#ifdef EH_FRAME_SECTION_NAME
  if (eh_frame_section == 0)
    {
      int flags;

      if (EH_TABLES_CAN_BE_READ_ONLY)
        {
          int fde_encoding;
          int per_encoding;
          int lsda_encoding;

          fde_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/1,
                                                       /*global=*/0);
          per_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/2,
                                                       /*global=*/1);
          lsda_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0,
                                                        /*global=*/0);
          flags = ((! flag_pic
                    || ((fde_encoding & 0x70) != DW_EH_PE_absptr
                        && (fde_encoding & 0x70) != DW_EH_PE_aligned
                        && (per_encoding & 0x70) != DW_EH_PE_absptr
                        && (per_encoding & 0x70) != DW_EH_PE_aligned
                        && (lsda_encoding & 0x70) != DW_EH_PE_absptr
                        && (lsda_encoding & 0x70) != DW_EH_PE_aligned))
                   ? 0 : SECTION_WRITE);
        }
      else
        flags = SECTION_WRITE;
      eh_frame_section = get_section (EH_FRAME_SECTION_NAME, flags, NULL);
    }
#endif /* EH_FRAME_SECTION_NAME */

  if (eh_frame_section)
    switch_to_section (eh_frame_section);
  else
    {
      /* We have no special eh_frame section.  Put the information in
         the data section and emit special labels to guide collect2.  */
      switch_to_section (data_section);

      if (!back)
        {
          label = get_file_function_name ("F");
          ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (PTR_SIZE));
          targetm.asm_out.globalize_label (asm_out_file,
                                           IDENTIFIER_POINTER (label));
          ASM_OUTPUT_LABEL (asm_out_file, IDENTIFIER_POINTER (label));
        }
    }
}

/* Switch [BACK] to the eh or debug frame table section, depending on
   FOR_EH.  */

static void
switch_to_frame_table_section (int for_eh, bool back)
{
  if (for_eh)
    switch_to_eh_frame_section (back);
  else
    {
      if (!debug_frame_section)
        debug_frame_section = get_section (DEBUG_FRAME_SECTION,
                                           SECTION_DEBUG, NULL);
      switch_to_section (debug_frame_section);
    }
}

/* Output a Call Frame Information opcode and its operand(s).  */

static void
output_cfi (dw_cfi_ref cfi, dw_fde_ref fde, int for_eh)
{
  unsigned long r;
  HOST_WIDE_INT off;

  if (cfi->dw_cfi_opc == DW_CFA_advance_loc)
    dw2_asm_output_data (1, (cfi->dw_cfi_opc
                             | (cfi->dw_cfi_oprnd1.dw_cfi_offset & 0x3f)),
                         "DW_CFA_advance_loc " HOST_WIDE_INT_PRINT_HEX,
                         ((unsigned HOST_WIDE_INT)
                          cfi->dw_cfi_oprnd1.dw_cfi_offset));
  else if (cfi->dw_cfi_opc == DW_CFA_offset)
    {
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
      dw2_asm_output_data (1, (cfi->dw_cfi_opc | (r & 0x3f)),
                           "DW_CFA_offset, column %#lx", r);
      off = div_data_align (cfi->dw_cfi_oprnd2.dw_cfi_offset);
      dw2_asm_output_data_uleb128 (off, NULL);
    }
  else if (cfi->dw_cfi_opc == DW_CFA_restore)
    {
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
      dw2_asm_output_data (1, (cfi->dw_cfi_opc | (r & 0x3f)),
                           "DW_CFA_restore, column %#lx", r);
    }
  else
    {
      dw2_asm_output_data (1, cfi->dw_cfi_opc,
                           "%s", dwarf_cfi_name (cfi->dw_cfi_opc));

      switch (cfi->dw_cfi_opc)
        {
        case DW_CFA_set_loc:
          if (for_eh)
            dw2_asm_output_encoded_addr_rtx (
                ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/1, /*global=*/0),
                gen_rtx_SYMBOL_REF (Pmode, cfi->dw_cfi_oprnd1.dw_cfi_addr),
                false, NULL);
          else
            dw2_asm_output_addr (DWARF2_ADDR_SIZE,
                                 cfi->dw_cfi_oprnd1.dw_cfi_addr, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_advance_loc1:
          dw2_asm_output_delta (1, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_advance_loc2:
          dw2_asm_output_delta (2, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_advance_loc4:
          dw2_asm_output_delta (4, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_MIPS_advance_loc8:
          dw2_asm_output_delta (8, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_offset_extended:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          off = div_data_align (cfi->dw_cfi_oprnd2.dw_cfi_offset);
          dw2_asm_output_data_uleb128 (off, NULL);
          break;

        case DW_CFA_def_cfa:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          dw2_asm_output_data_uleb128 (cfi->dw_cfi_oprnd2.dw_cfi_offset, NULL);
          break;

        case DW_CFA_offset_extended_sf:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          off = div_data_align (cfi->dw_cfi_oprnd2.dw_cfi_offset);
          dw2_asm_output_data_sleb128 (off, NULL);
          break;

        case DW_CFA_def_cfa_sf:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          off = div_data_align (cfi->dw_cfi_oprnd2.dw_cfi_offset);
          dw2_asm_output_data_sleb128 (off, NULL);
          break;

        case DW_CFA_restore_extended:
        case DW_CFA_undefined:
        case DW_CFA_same_value:
        case DW_CFA_def_cfa_register:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          break;

        case DW_CFA_register:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd2.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          break;

        case DW_CFA_def_cfa_offset:
        case DW_CFA_GNU_args_size:
          dw2_asm_output_data_uleb128 (cfi->dw_cfi_oprnd1.dw_cfi_offset, NULL);
          break;

        case DW_CFA_def_cfa_offset_sf:
          off = div_data_align (cfi->dw_cfi_oprnd1.dw_cfi_offset);
          dw2_asm_output_data_sleb128 (off, NULL);
          break;

        case DW_CFA_GNU_window_save:
          break;

        case DW_CFA_def_cfa_expression:
        case DW_CFA_expression:
          output_cfa_loc (cfi);
          break;

        case DW_CFA_GNU_negative_offset_extended:
          /* Obsoleted by DW_CFA_offset_extended_sf.  */
          gcc_unreachable ();

        default:
          break;
        }
    }
}

/* Similar, but do it via assembler directives instead.  */

static void
output_cfi_directive (dw_cfi_ref cfi)
{
  unsigned long r, r2;

  switch (cfi->dw_cfi_opc)
    {
    case DW_CFA_advance_loc:
    case DW_CFA_advance_loc1:
    case DW_CFA_advance_loc2:
    case DW_CFA_advance_loc4:
    case DW_CFA_MIPS_advance_loc8:
    case DW_CFA_set_loc:
      /* Should only be created by add_fde_cfi in a code path not
         followed when emitting via directives.  The assembler is
         going to take care of this for us.  */
      gcc_unreachable ();

    case DW_CFA_offset:
    case DW_CFA_offset_extended:
    case DW_CFA_offset_extended_sf:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_offset %lu, "HOST_WIDE_INT_PRINT_DEC"\n",
               r, cfi->dw_cfi_oprnd2.dw_cfi_offset);
      break;

    case DW_CFA_restore:
    case DW_CFA_restore_extended:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_restore %lu\n", r);
      break;

    case DW_CFA_undefined:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_undefined %lu\n", r);
      break;

    case DW_CFA_same_value:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_same_value %lu\n", r);
      break;

    case DW_CFA_def_cfa:
    case DW_CFA_def_cfa_sf:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_def_cfa %lu, "HOST_WIDE_INT_PRINT_DEC"\n",
               r, cfi->dw_cfi_oprnd2.dw_cfi_offset);
      break;

    case DW_CFA_def_cfa_register:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_def_cfa_register %lu\n", r);
      break;

    case DW_CFA_register:
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, 1);
      r2 = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd2.dw_cfi_reg_num, 1);
      fprintf (asm_out_file, "\t.cfi_register %lu, %lu\n", r, r2);
      break;

    case DW_CFA_def_cfa_offset:
    case DW_CFA_def_cfa_offset_sf:
      fprintf (asm_out_file, "\t.cfi_def_cfa_offset "
               HOST_WIDE_INT_PRINT_DEC"\n",
               cfi->dw_cfi_oprnd1.dw_cfi_offset);
      break;

    case DW_CFA_remember_state:
      fprintf (asm_out_file, "\t.cfi_remember_state\n");
      break;
    case DW_CFA_restore_state:
      fprintf (asm_out_file, "\t.cfi_restore_state\n");
      break;

    case DW_CFA_GNU_args_size:
      fprintf (asm_out_file, "\t.cfi_escape %#x,", DW_CFA_GNU_args_size);
      dw2_asm_output_data_uleb128_raw (cfi->dw_cfi_oprnd1.dw_cfi_offset);
      if (flag_debug_asm)
        fprintf (asm_out_file, "\t%s args_size "HOST_WIDE_INT_PRINT_DEC,
                 ASM_COMMENT_START, cfi->dw_cfi_oprnd1.dw_cfi_offset);
      fputc ('\n', asm_out_file);
      break;

    case DW_CFA_GNU_window_save:
      fprintf (asm_out_file, "\t.cfi_window_save\n");
      break;

    case DW_CFA_def_cfa_expression:
    case DW_CFA_expression:
      fprintf (asm_out_file, "\t.cfi_escape %#x,", cfi->dw_cfi_opc);
      output_cfa_loc_raw (cfi);
      fputc ('\n', asm_out_file);
      break;

    default:
      gcc_unreachable ();
    }
}

DEF_VEC_P (dw_cfi_ref);
DEF_VEC_ALLOC_P (dw_cfi_ref, heap);

/* Output CFIs to bring current FDE to the same state as after executing
   CFIs in CFI chain.  DO_CFI_ASM is true if .cfi_* directives shall
   be emitted, false otherwise.  If it is false, FDE and FOR_EH are the
   other arguments to pass to output_cfi.  */

static void
output_cfis (dw_cfi_ref cfi, bool do_cfi_asm, dw_fde_ref fde, bool for_eh)
{
  struct dw_cfi_struct cfi_buf;
  dw_cfi_ref cfi2;
  dw_cfi_ref cfi_args_size = NULL, cfi_cfa = NULL, cfi_cfa_offset = NULL;
  VEC (dw_cfi_ref, heap) *regs = VEC_alloc (dw_cfi_ref, heap, 32);
  unsigned int len, idx;

  for (;; cfi = cfi->dw_cfi_next)
    switch (cfi ? cfi->dw_cfi_opc : DW_CFA_nop)
      {
      case DW_CFA_advance_loc:
      case DW_CFA_advance_loc1:
      case DW_CFA_advance_loc2:
      case DW_CFA_advance_loc4:
      case DW_CFA_MIPS_advance_loc8:
      case DW_CFA_set_loc:
        /* All advances should be ignored.  */
        break;
      case DW_CFA_remember_state:
        {
          dw_cfi_ref args_size = cfi_args_size;

          /* Skip everything between .cfi_remember_state and
             .cfi_restore_state.  */
          for (cfi2 = cfi->dw_cfi_next; cfi2; cfi2 = cfi2->dw_cfi_next)
            if (cfi2->dw_cfi_opc == DW_CFA_restore_state)
              break;
            else if (cfi2->dw_cfi_opc == DW_CFA_GNU_args_size)
              args_size = cfi2;
            else
              gcc_assert (cfi2->dw_cfi_opc != DW_CFA_remember_state);

          if (cfi2 == NULL)
            goto flush_all;
          else
            {
              cfi = cfi2;
              cfi_args_size = args_size;
            }
          break;
        }
      case DW_CFA_GNU_args_size:
        cfi_args_size = cfi;
        break;
      case DW_CFA_GNU_window_save:
        goto flush_all;
      case DW_CFA_offset:
      case DW_CFA_offset_extended:
      case DW_CFA_offset_extended_sf:
      case DW_CFA_restore:
      case DW_CFA_restore_extended:
      case DW_CFA_undefined:
      case DW_CFA_same_value:
      case DW_CFA_register:
      case DW_CFA_val_offset:
      case DW_CFA_val_offset_sf:
      case DW_CFA_expression:
      case DW_CFA_val_expression:
      case DW_CFA_GNU_negative_offset_extended:
        if (VEC_length (dw_cfi_ref, regs) <= cfi->dw_cfi_oprnd1.dw_cfi_reg_num)
          VEC_safe_grow_cleared (dw_cfi_ref, heap, regs,
                                 cfi->dw_cfi_oprnd1.dw_cfi_reg_num + 1);
        VEC_replace (dw_cfi_ref, regs, cfi->dw_cfi_oprnd1.dw_cfi_reg_num, cfi);
        break;
      case DW_CFA_def_cfa:
      case DW_CFA_def_cfa_sf:
      case DW_CFA_def_cfa_expression:
        cfi_cfa = cfi;
        cfi_cfa_offset = cfi;
        break;
      case DW_CFA_def_cfa_register:
        cfi_cfa = cfi;
        break;
      case DW_CFA_def_cfa_offset:
      case DW_CFA_def_cfa_offset_sf:
        cfi_cfa_offset = cfi;
        break;
      case DW_CFA_nop:
        gcc_assert (cfi == NULL);
      flush_all:
        len = VEC_length (dw_cfi_ref, regs);
        for (idx = 0; idx < len; idx++)
          {
            cfi2 = VEC_replace (dw_cfi_ref, regs, idx, NULL);
            if (cfi2 != NULL
                && cfi2->dw_cfi_opc != DW_CFA_restore
                && cfi2->dw_cfi_opc != DW_CFA_restore_extended)
              {
                if (do_cfi_asm)
                  output_cfi_directive (cfi2);
                else
                  output_cfi (cfi2, fde, for_eh);
              }
          }
        if (cfi_cfa && cfi_cfa_offset && cfi_cfa_offset != cfi_cfa)
          {
            gcc_assert (cfi_cfa->dw_cfi_opc != DW_CFA_def_cfa_expression);
            cfi_buf = *cfi_cfa;
            switch (cfi_cfa_offset->dw_cfi_opc)
              {
              case DW_CFA_def_cfa_offset:
                cfi_buf.dw_cfi_opc = DW_CFA_def_cfa;
                cfi_buf.dw_cfi_oprnd2 = cfi_cfa_offset->dw_cfi_oprnd1;
                break;
              case DW_CFA_def_cfa_offset_sf:
                cfi_buf.dw_cfi_opc = DW_CFA_def_cfa_sf;
                cfi_buf.dw_cfi_oprnd2 = cfi_cfa_offset->dw_cfi_oprnd1;
                break;
              case DW_CFA_def_cfa:
              case DW_CFA_def_cfa_sf:
                cfi_buf.dw_cfi_opc = cfi_cfa_offset->dw_cfi_opc;
                cfi_buf.dw_cfi_oprnd2 = cfi_cfa_offset->dw_cfi_oprnd2;
                break;
              default:
                gcc_unreachable ();
              }
            cfi_cfa = &cfi_buf;
          }
        else if (cfi_cfa_offset)
          cfi_cfa = cfi_cfa_offset;
        if (cfi_cfa)
          {
            if (do_cfi_asm)
              output_cfi_directive (cfi_cfa);
            else
              output_cfi (cfi_cfa, fde, for_eh);
          }
        cfi_cfa = NULL;
        cfi_cfa_offset = NULL;
        if (cfi_args_size
            && cfi_args_size->dw_cfi_oprnd1.dw_cfi_offset)
          {
            if (do_cfi_asm)
              output_cfi_directive (cfi_args_size);
            else
              output_cfi (cfi_args_size, fde, for_eh);
          }
        cfi_args_size = NULL;
        if (cfi == NULL)
          {
            VEC_free (dw_cfi_ref, heap, regs);
            return;
          }
        else if (do_cfi_asm)
          output_cfi_directive (cfi);
        else
          output_cfi (cfi, fde, for_eh);
        break;
      default:
        gcc_unreachable ();
    }
}

/* Output one FDE.  */

static void
output_fde (dw_fde_ref fde, bool for_eh, bool second,
            char *section_start_label, int fde_encoding, char *augmentation,
            bool any_lsda_needed, int lsda_encoding)
{
  const char *begin, *end;
  static unsigned int j;
  char l1[20], l2[20];
  dw_cfi_ref cfi;

  targetm.asm_out.emit_unwind_label (asm_out_file, fde->decl, for_eh,
                                     /* empty */ 0);
  targetm.asm_out.internal_label (asm_out_file, FDE_LABEL,
                                  for_eh + j);
  ASM_GENERATE_INTERNAL_LABEL (l1, FDE_AFTER_SIZE_LABEL, for_eh + j);
  ASM_GENERATE_INTERNAL_LABEL (l2, FDE_END_LABEL, for_eh + j);
  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4 && !for_eh)
    dw2_asm_output_data (4, 0xffffffff, "Initial length escape value"
                         " indicating 64-bit DWARF extension");
  dw2_asm_output_delta (for_eh ? 4 : DWARF_OFFSET_SIZE, l2, l1,
                        "FDE Length");
  ASM_OUTPUT_LABEL (asm_out_file, l1);

  if (for_eh)
    dw2_asm_output_delta (4, l1, section_start_label, "FDE CIE offset");
  else
    dw2_asm_output_offset (DWARF_OFFSET_SIZE, section_start_label,
                           debug_frame_section, "FDE CIE offset");

  if (!fde->dw_fde_switched_sections)
    {
      begin = fde->dw_fde_begin;
      end = fde->dw_fde_end;
    }
  else
    {
      /* For the first section, prefer dw_fde_begin over
         dw_fde_{hot,cold}_section_label, as the latter
         might be separated from the real start of the
         function by alignment padding.  */
      if (!second)
        begin = fde->dw_fde_begin;
      else if (fde->dw_fde_switched_cold_to_hot)
        begin = fde->dw_fde_hot_section_label;
      else
        begin = fde->dw_fde_unlikely_section_label;
      if (second ^ fde->dw_fde_switched_cold_to_hot)
        end = fde->dw_fde_unlikely_section_end_label;
      else
        end = fde->dw_fde_hot_section_end_label;
    }

  if (for_eh)
    {
      rtx sym_ref = gen_rtx_SYMBOL_REF (Pmode, begin);
      SYMBOL_REF_FLAGS (sym_ref) |= SYMBOL_FLAG_LOCAL;
      dw2_asm_output_encoded_addr_rtx (fde_encoding, sym_ref, false,
                                       "FDE initial location");
      dw2_asm_output_delta (size_of_encoded_value (fde_encoding),
                            end, begin, "FDE address range");
    }
  else
    {
      dw2_asm_output_addr (DWARF2_ADDR_SIZE, begin, "FDE initial location");
      dw2_asm_output_delta (DWARF2_ADDR_SIZE, end, begin, "FDE address range");
    }

  if (augmentation[0])
    {
      if (any_lsda_needed)
        {
          int size = size_of_encoded_value (lsda_encoding);

          if (lsda_encoding == DW_EH_PE_aligned)
            {
              int offset = (  4         /* Length */
                            + 4         /* CIE offset */
                            + 2 * size_of_encoded_value (fde_encoding)
                            + 1         /* Augmentation size */ );
              int pad = -offset & (PTR_SIZE - 1);

              size += pad;
              gcc_assert (size_of_uleb128 (size) == 1);
            }

          dw2_asm_output_data_uleb128 (size, "Augmentation size");

          if (fde->uses_eh_lsda)
            {
              ASM_GENERATE_INTERNAL_LABEL (l1, second ? "LLSDAC" : "LLSDA",
                                           fde->funcdef_number);
              dw2_asm_output_encoded_addr_rtx (lsda_encoding,
                                               gen_rtx_SYMBOL_REF (Pmode, l1),
                                               false,
                                               "Language Specific Data Area");
            }
          else
            {
              if (lsda_encoding == DW_EH_PE_aligned)
                ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (PTR_SIZE));
              dw2_asm_output_data (size_of_encoded_value (lsda_encoding), 0,
                                   "Language Specific Data Area (none)");
            }
        }
      else
        dw2_asm_output_data_uleb128 (0, "Augmentation size");
    }

  /* Loop through the Call Frame Instructions associated with
     this FDE.  */
  fde->dw_fde_current_label = begin;
  if (!fde->dw_fde_switched_sections)
    for (cfi = fde->dw_fde_cfi; cfi != NULL; cfi = cfi->dw_cfi_next)
      output_cfi (cfi, fde, for_eh);
  else if (!second)
    {
      if (fde->dw_fde_switch_cfi)
        for (cfi = fde->dw_fde_cfi; cfi != NULL; cfi = cfi->dw_cfi_next)
          {
            output_cfi (cfi, fde, for_eh);
            if (cfi == fde->dw_fde_switch_cfi)
              break;
          }
    }
  else
    {
      dw_cfi_ref cfi_next = fde->dw_fde_cfi;

      if (fde->dw_fde_switch_cfi)
        {
          cfi_next = fde->dw_fde_switch_cfi->dw_cfi_next;
          fde->dw_fde_switch_cfi->dw_cfi_next = NULL;
          output_cfis (fde->dw_fde_cfi, false, fde, for_eh);
          fde->dw_fde_switch_cfi->dw_cfi_next = cfi_next;
        }
      for (cfi = cfi_next; cfi != NULL; cfi = cfi->dw_cfi_next)
        output_cfi (cfi, fde, for_eh);
    }

  /* If we are to emit a ref/link from function bodies to their frame tables,
     do it now.  This is typically performed to make sure that tables
     associated with functions are dragged with them and not discarded in
     garbage collecting links. We need to do this on a per function basis to
     cope with -ffunction-sections.  */

#ifdef ASM_OUTPUT_DWARF_TABLE_REF
  /* Switch to the function section, emit the ref to the tables, and
     switch *back* into the table section.  */
  switch_to_section (function_section (fde->decl));
  ASM_OUTPUT_DWARF_TABLE_REF (section_start_label);
  switch_to_frame_table_section (for_eh, true);
#endif

  /* Pad the FDE out to an address sized boundary.  */
  ASM_OUTPUT_ALIGN (asm_out_file,
                    floor_log2 ((for_eh ? PTR_SIZE : DWARF2_ADDR_SIZE)));
  ASM_OUTPUT_LABEL (asm_out_file, l2);

  j += 2;
}

/* Return true if frame description entry FDE is needed for EH.  */

static bool
fde_needed_for_eh_p (dw_fde_ref fde)
{
  if (flag_asynchronous_unwind_tables)
    return true;

  if (TARGET_USES_WEAK_UNWIND_INFO && DECL_WEAK (fde->decl))
    return true;

  if (fde->uses_eh_lsda)
    return true;

  /* If exceptions are enabled, we have collected nothrow info.  */
  if (flag_exceptions && (fde->all_throwers_are_sibcalls || fde->nothrow))
    return false;

  return true;
}

/* Output the call frame information used to record information
   that relates to calculating the frame pointer, and records the
   location of saved registers.  */

static void
output_call_frame_info (int for_eh)
{
  unsigned int i;
  dw_fde_ref fde;
  dw_cfi_ref cfi;
  char l1[20], l2[20], section_start_label[20];
  bool any_lsda_needed = false;
  char augmentation[6];
  int augmentation_size;
  int fde_encoding = DW_EH_PE_absptr;
  int per_encoding = DW_EH_PE_absptr;
  int lsda_encoding = DW_EH_PE_absptr;
  int return_reg;
  rtx personality = NULL;
  int dw_cie_version;

  /* Don't emit a CIE if there won't be any FDEs.  */
  if (fde_table_in_use == 0)
    return;

  /* Nothing to do if the assembler's doing it all.  */
  if (dwarf2out_do_cfi_asm ())
    return;

  /* If we don't have any functions we'll want to unwind out of, don't emit
     any EH unwind information.  If we make FDEs linkonce, we may have to
     emit an empty label for an FDE that wouldn't otherwise be emitted.  We
     want to avoid having an FDE kept around when the function it refers to
     is discarded.  Example where this matters: a primary function template
     in C++ requires EH information, an explicit specialization doesn't.  */
  if (for_eh)
    {
      bool any_eh_needed = false;

      for (i = 0; i < fde_table_in_use; i++)
        if (fde_table[i].uses_eh_lsda)
          any_eh_needed = any_lsda_needed = true;
        else if (fde_needed_for_eh_p (&fde_table[i]))
          any_eh_needed = true;
        else if (TARGET_USES_WEAK_UNWIND_INFO)
          targetm.asm_out.emit_unwind_label (asm_out_file, fde_table[i].decl,
                                             1, 1);

      if (!any_eh_needed)
        return;
    }

  /* We're going to be generating comments, so turn on app.  */
  if (flag_debug_asm)
    app_enable ();

  /* Switch to the proper frame section, first time.  */
  switch_to_frame_table_section (for_eh, false);

  ASM_GENERATE_INTERNAL_LABEL (section_start_label, FRAME_BEGIN_LABEL, for_eh);
  ASM_OUTPUT_LABEL (asm_out_file, section_start_label);

  /* Output the CIE.  */
  ASM_GENERATE_INTERNAL_LABEL (l1, CIE_AFTER_SIZE_LABEL, for_eh);
  ASM_GENERATE_INTERNAL_LABEL (l2, CIE_END_LABEL, for_eh);
  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4 && !for_eh)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  dw2_asm_output_delta (for_eh ? 4 : DWARF_OFFSET_SIZE, l2, l1,
                        "Length of Common Information Entry");
  ASM_OUTPUT_LABEL (asm_out_file, l1);

  /* Now that the CIE pointer is PC-relative for EH,
     use 0 to identify the CIE.  */
  dw2_asm_output_data ((for_eh ? 4 : DWARF_OFFSET_SIZE),
                       (for_eh ? 0 : DWARF_CIE_ID),
                       "CIE Identifier Tag");

  /* Use the CIE version 3 for DWARF3; allow DWARF2 to continue to
     use CIE version 1, unless that would produce incorrect results
     due to overflowing the return register column.  */
  return_reg = DWARF2_FRAME_REG_OUT (DWARF_FRAME_RETURN_COLUMN, for_eh);
  dw_cie_version = 1;
  if (return_reg >= 256 || dwarf_version > 2)
    dw_cie_version = 3;
  dw2_asm_output_data (1, dw_cie_version, "CIE Version");

  augmentation[0] = 0;
  augmentation_size = 0;

  personality = current_unit_personality;
  if (for_eh)
    {
      char *p;

      /* Augmentation:
         z      Indicates that a uleb128 is present to size the
                augmentation section.
         L      Indicates the encoding (and thus presence) of
                an LSDA pointer in the FDE augmentation.
         R      Indicates a non-default pointer encoding for
                FDE code pointers.
         P      Indicates the presence of an encoding + language
                personality routine in the CIE augmentation.  */

      fde_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/1, /*global=*/0);
      per_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/2, /*global=*/1);
      lsda_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/0);

      p = augmentation + 1;
      if (personality)
        {
          *p++ = 'P';
          augmentation_size += 1 + size_of_encoded_value (per_encoding);
          assemble_external_libcall (personality);
        }
      if (any_lsda_needed)
        {
          *p++ = 'L';
          augmentation_size += 1;
        }
      if (fde_encoding != DW_EH_PE_absptr)
        {
          *p++ = 'R';
          augmentation_size += 1;
        }
      if (p > augmentation + 1)
        {
          augmentation[0] = 'z';
          *p = '\0';
        }

      /* Ug.  Some platforms can't do unaligned dynamic relocations at all.  */
      if (personality && per_encoding == DW_EH_PE_aligned)
        {
          int offset = (  4             /* Length */
                        + 4             /* CIE Id */
                        + 1             /* CIE version */
                        + strlen (augmentation) + 1     /* Augmentation */
                        + size_of_uleb128 (1)           /* Code alignment */
                        + size_of_sleb128 (DWARF_CIE_DATA_ALIGNMENT)
                        + 1             /* RA column */
                        + 1             /* Augmentation size */
                        + 1             /* Personality encoding */ );
          int pad = -offset & (PTR_SIZE - 1);

          augmentation_size += pad;

          /* Augmentations should be small, so there's scarce need to
             iterate for a solution.  Die if we exceed one uleb128 byte.  */
          gcc_assert (size_of_uleb128 (augmentation_size) == 1);
        }
    }

  dw2_asm_output_nstring (augmentation, -1, "CIE Augmentation");
  if (dw_cie_version >= 4)
    {
      dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "CIE Address Size");
      dw2_asm_output_data (1, 0, "CIE Segment Size");
    }
  dw2_asm_output_data_uleb128 (1, "CIE Code Alignment Factor");
  dw2_asm_output_data_sleb128 (DWARF_CIE_DATA_ALIGNMENT,
                               "CIE Data Alignment Factor");

  if (dw_cie_version == 1)
    dw2_asm_output_data (1, return_reg, "CIE RA Column");
  else
    dw2_asm_output_data_uleb128 (return_reg, "CIE RA Column");

  if (augmentation[0])
    {
      dw2_asm_output_data_uleb128 (augmentation_size, "Augmentation size");
      if (personality)
        {
          dw2_asm_output_data (1, per_encoding, "Personality (%s)",
                               eh_data_format_name (per_encoding));
          dw2_asm_output_encoded_addr_rtx (per_encoding,
                                           personality,
                                           true, NULL);
        }

      if (any_lsda_needed)
        dw2_asm_output_data (1, lsda_encoding, "LSDA Encoding (%s)",
                             eh_data_format_name (lsda_encoding));

      if (fde_encoding != DW_EH_PE_absptr)
        dw2_asm_output_data (1, fde_encoding, "FDE Encoding (%s)",
                             eh_data_format_name (fde_encoding));
    }

  for (cfi = cie_cfi_head; cfi != NULL; cfi = cfi->dw_cfi_next)
    output_cfi (cfi, NULL, for_eh);

  /* Pad the CIE out to an address sized boundary.  */
  ASM_OUTPUT_ALIGN (asm_out_file,
                    floor_log2 (for_eh ? PTR_SIZE : DWARF2_ADDR_SIZE));
  ASM_OUTPUT_LABEL (asm_out_file, l2);

  /* Loop through all of the FDE's.  */
  for (i = 0; i < fde_table_in_use; i++)
    {
      unsigned int k;
      fde = &fde_table[i];

      /* Don't emit EH unwind info for leaf functions that don't need it.  */
      if (for_eh && !fde_needed_for_eh_p (fde))
        continue;

      for (k = 0; k < (fde->dw_fde_switched_sections ? 2 : 1); k++)
        output_fde (fde, for_eh, k, section_start_label, fde_encoding,
                    augmentation, any_lsda_needed, lsda_encoding);
    }

  if (for_eh && targetm.terminate_dw2_eh_frame_info)
    dw2_asm_output_data (4, 0, "End of Table");
#ifdef MIPS_DEBUGGING_INFO
  /* Work around Irix 6 assembler bug whereby labels at the end of a section
     get a value of 0.  Putting .align 0 after the label fixes it.  */
  ASM_OUTPUT_ALIGN (asm_out_file, 0);
#endif

  /* Turn off app to make assembly quicker.  */
  if (flag_debug_asm)
    app_disable ();
}

/* Emit .cfi_startproc and .cfi_personality/.cfi_lsda if needed.  */

static void
dwarf2out_do_cfi_startproc (bool second)
{
  int enc;
  rtx ref;
  rtx personality = get_personality_function (current_function_decl);

  fprintf (asm_out_file, "\t.cfi_startproc\n");

  if (personality)
    {
      enc = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/2, /*global=*/1);
      ref = personality;

      /* ??? The GAS support isn't entirely consistent.  We have to
         handle indirect support ourselves, but PC-relative is done
         in the assembler.  Further, the assembler can't handle any
         of the weirder relocation types.  */
      if (enc & DW_EH_PE_indirect)
        ref = dw2_force_const_mem (ref, true);

      fprintf (asm_out_file, "\t.cfi_personality %#x,", enc);
      output_addr_const (asm_out_file, ref);
      fputc ('\n', asm_out_file);
    }

  if (crtl->uses_eh_lsda)
    {
      char lab[20];

      enc = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/0);
      ASM_GENERATE_INTERNAL_LABEL (lab, second ? "LLSDAC" : "LLSDA",
                                   current_function_funcdef_no);
      ref = gen_rtx_SYMBOL_REF (Pmode, lab);
      SYMBOL_REF_FLAGS (ref) = SYMBOL_FLAG_LOCAL;

      if (enc & DW_EH_PE_indirect)
        ref = dw2_force_const_mem (ref, true);

      fprintf (asm_out_file, "\t.cfi_lsda %#x,", enc);
      output_addr_const (asm_out_file, ref);
      fputc ('\n', asm_out_file);
    }
}

/* Output a marker (i.e. a label) for the beginning of a function, before
   the prologue.  */

void
dwarf2out_begin_prologue (unsigned int line ATTRIBUTE_UNUSED,
                          const char *file ATTRIBUTE_UNUSED)
{
  char label[MAX_ARTIFICIAL_LABEL_BYTES];
  char * dup_label;
  dw_fde_ref fde;
  section *fnsec;
  bool do_frame;

  current_function_func_begin_label = NULL;

  do_frame = dwarf2out_do_frame ();

  /* ??? current_function_func_begin_label is also used by except.c for
     call-site information.  We must emit this label if it might be used.  */
  if (!do_frame
      && (!flag_exceptions
          || targetm.except_unwind_info (&global_options) != UI_TARGET))
    return;

  fnsec = function_section (current_function_decl);
  switch_to_section (fnsec);
  ASM_GENERATE_INTERNAL_LABEL (label, FUNC_BEGIN_LABEL,
                               current_function_funcdef_no);
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, FUNC_BEGIN_LABEL,
                          current_function_funcdef_no);
  dup_label = xstrdup (label);
  current_function_func_begin_label = dup_label;

  /* We can elide the fde allocation if we're not emitting debug info.  */
  if (!do_frame)
    return;

  /* Expand the fde table if necessary.  */
  if (fde_table_in_use == fde_table_allocated)
    {
      fde_table_allocated += FDE_TABLE_INCREMENT;
      fde_table = GGC_RESIZEVEC (dw_fde_node, fde_table, fde_table_allocated);
      memset (fde_table + fde_table_in_use, 0,
              FDE_TABLE_INCREMENT * sizeof (dw_fde_node));
    }

  /* Record the FDE associated with this function.  */
  current_funcdef_fde = fde_table_in_use;

  /* Add the new FDE at the end of the fde_table.  */
  fde = &fde_table[fde_table_in_use++];
  fde->decl = current_function_decl;
  fde->dw_fde_begin = dup_label;
  fde->dw_fde_current_label = dup_label;
  fde->dw_fde_hot_section_label = NULL;
  fde->dw_fde_hot_section_end_label = NULL;
  fde->dw_fde_unlikely_section_label = NULL;
  fde->dw_fde_unlikely_section_end_label = NULL;
  fde->dw_fde_switched_sections = 0;
  fde->dw_fde_switched_cold_to_hot = 0;
  fde->dw_fde_end = NULL;
  fde->dw_fde_vms_end_prologue = NULL;
  fde->dw_fde_vms_begin_epilogue = NULL;
  fde->dw_fde_cfi = NULL;
  fde->dw_fde_switch_cfi = NULL;
  fde->funcdef_number = current_function_funcdef_no;
  fde->all_throwers_are_sibcalls = crtl->all_throwers_are_sibcalls;
  fde->uses_eh_lsda = crtl->uses_eh_lsda;
  fde->nothrow = crtl->nothrow;
  fde->drap_reg = INVALID_REGNUM;
  fde->vdrap_reg = INVALID_REGNUM;
  if (flag_reorder_blocks_and_partition)
    {
      section *unlikelysec;
      if (first_function_block_is_cold)
        fde->in_std_section = 1;
      else
        fde->in_std_section
          = (fnsec == text_section
             || (cold_text_section && fnsec == cold_text_section));
      unlikelysec = unlikely_text_section ();
      fde->cold_in_std_section
        = (unlikelysec == text_section
           || (cold_text_section && unlikelysec == cold_text_section));
    }
  else
    {
      fde->in_std_section
        = (fnsec == text_section
           || (cold_text_section && fnsec == cold_text_section));
      fde->cold_in_std_section = 0;
    }

  args_size = old_args_size = 0;

  /* We only want to output line number information for the genuine dwarf2
     prologue case, not the eh frame case.  */
#ifdef DWARF2_DEBUGGING_INFO
  if (file)
    dwarf2out_source_line (line, file, 0, true);
#endif

  if (dwarf2out_do_cfi_asm ())
    dwarf2out_do_cfi_startproc (false);
  else
    {
      rtx personality = get_personality_function (current_function_decl);
      if (!current_unit_personality)
        current_unit_personality = personality;

      /* We cannot keep a current personality per function as without CFI
         asm, at the point where we emit the CFI data, there is no current
         function anymore.  */
      if (personality && current_unit_personality != personality)
        sorry ("multiple EH personalities are supported only with assemblers "
               "supporting .cfi_personality directive");
    }
}

/* Output a marker (i.e. a label) for the end of the generated code
   for a function prologue.  This gets called *after* the prologue code has
   been generated.  */

void
dwarf2out_vms_end_prologue (unsigned int line ATTRIBUTE_UNUSED,
                        const char *file ATTRIBUTE_UNUSED)
{
  dw_fde_ref fde;
  char label[MAX_ARTIFICIAL_LABEL_BYTES];

  /* Output a label to mark the endpoint of the code generated for this
     function.  */
  ASM_GENERATE_INTERNAL_LABEL (label, PROLOGUE_END_LABEL,
                               current_function_funcdef_no);
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, PROLOGUE_END_LABEL,
                          current_function_funcdef_no);
  fde = &fde_table[fde_table_in_use - 1];
  fde->dw_fde_vms_end_prologue = xstrdup (label);
}

/* Output a marker (i.e. a label) for the beginning of the generated code
   for a function epilogue.  This gets called *before* the prologue code has
   been generated.  */

void
dwarf2out_vms_begin_epilogue (unsigned int line ATTRIBUTE_UNUSED,
                          const char *file ATTRIBUTE_UNUSED)
{
  dw_fde_ref fde;
  char label[MAX_ARTIFICIAL_LABEL_BYTES];

  fde = &fde_table[fde_table_in_use - 1];
  if (fde->dw_fde_vms_begin_epilogue)
    return;

  /* Output a label to mark the endpoint of the code generated for this
     function.  */
  ASM_GENERATE_INTERNAL_LABEL (label, EPILOGUE_BEGIN_LABEL,
                               current_function_funcdef_no);
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, EPILOGUE_BEGIN_LABEL,
                          current_function_funcdef_no);
  fde->dw_fde_vms_begin_epilogue = xstrdup (label);
}

/* Output a marker (i.e. a label) for the absolute end of the generated code
   for a function definition.  This gets called *after* the epilogue code has
   been generated.  */

void
dwarf2out_end_epilogue (unsigned int line ATTRIBUTE_UNUSED,
                        const char *file ATTRIBUTE_UNUSED)
{
  dw_fde_ref fde;
  char label[MAX_ARTIFICIAL_LABEL_BYTES];

  last_var_location_insn = NULL_RTX;

  if (dwarf2out_do_cfi_asm ())
    fprintf (asm_out_file, "\t.cfi_endproc\n");

  /* Output a label to mark the endpoint of the code generated for this
     function.  */
  ASM_GENERATE_INTERNAL_LABEL (label, FUNC_END_LABEL,
                               current_function_funcdef_no);
  ASM_OUTPUT_LABEL (asm_out_file, label);
  fde = current_fde ();
  gcc_assert (fde != NULL);
  fde->dw_fde_end = xstrdup (label);
}

void
dwarf2out_frame_init (void)
{
  /* Allocate the initial hunk of the fde_table.  */
  fde_table = ggc_alloc_cleared_vec_dw_fde_node (FDE_TABLE_INCREMENT);
  fde_table_allocated = FDE_TABLE_INCREMENT;
  fde_table_in_use = 0;

  /* Generate the CFA instructions common to all FDE's.  Do it now for the
     sake of lookup_cfa.  */

  /* On entry, the Canonical Frame Address is at SP.  */
  dwarf2out_def_cfa (NULL, STACK_POINTER_REGNUM, INCOMING_FRAME_SP_OFFSET);

  if (targetm.debug_unwind_info () == UI_DWARF2
      || targetm.except_unwind_info (&global_options) == UI_DWARF2)
    initial_return_save (INCOMING_RETURN_ADDR_RTX);
}

void
dwarf2out_frame_finish (void)
{
  /* Output call frame information.  */
  if (targetm.debug_unwind_info () == UI_DWARF2)
    output_call_frame_info (0);

  /* Output another copy for the unwinder.  */
  if ((flag_unwind_tables || flag_exceptions)
      && targetm.except_unwind_info (&global_options) == UI_DWARF2)
    output_call_frame_info (1);
}

/* Note that the current function section is being used for code.  */

static void
dwarf2out_note_section_used (void)
{
  section *sec = current_function_section ();
  if (sec == text_section)
    text_section_used = true;
  else if (sec == cold_text_section)
    cold_text_section_used = true;
}

void
dwarf2out_switch_text_section (void)
{
  dw_fde_ref fde = current_fde ();

  gcc_assert (cfun && fde && !fde->dw_fde_switched_sections);

  fde->dw_fde_switched_sections = 1;
  fde->dw_fde_switched_cold_to_hot = !in_cold_section_p;

  fde->dw_fde_hot_section_label = crtl->subsections.hot_section_label;
  fde->dw_fde_hot_section_end_label = crtl->subsections.hot_section_end_label;
  fde->dw_fde_unlikely_section_label = crtl->subsections.cold_section_label;
  fde->dw_fde_unlikely_section_end_label = crtl->subsections.cold_section_end_label;
  have_multiple_function_sections = true;

  /* Reset the current label on switching text sections, so that we
     don't attempt to advance_loc4 between labels in different sections.  */
  fde->dw_fde_current_label = NULL;

  /* There is no need to mark used sections when not debugging.  */
  if (cold_text_section != NULL)
    dwarf2out_note_section_used ();

  if (dwarf2out_do_cfi_asm ())
    fprintf (asm_out_file, "\t.cfi_endproc\n");

  /* Now do the real section switch.  */
  switch_to_section (current_function_section ());

  if (dwarf2out_do_cfi_asm ())
    {
      dwarf2out_do_cfi_startproc (true);
      /* As this is a different FDE, insert all current CFI instructions
         again.  */
      output_cfis (fde->dw_fde_cfi, true, fde, true);
    }
  else
    {
      dw_cfi_ref cfi = fde->dw_fde_cfi;

      cfi = fde->dw_fde_cfi;
      if (cfi)
        while (cfi->dw_cfi_next != NULL)
          cfi = cfi->dw_cfi_next;
      fde->dw_fde_switch_cfi = cfi;
    }
}
\f
/* And now, the subset of the debugging information support code necessary
   for emitting location expressions.  */

/* Data about a single source file.  */
struct GTY(()) dwarf_file_data {
  const char * filename;
  int emitted_number;
};

typedef struct dw_val_struct *dw_val_ref;
typedef struct die_struct *dw_die_ref;
typedef const struct die_struct *const_dw_die_ref;
typedef struct dw_loc_descr_struct *dw_loc_descr_ref;
typedef struct dw_loc_list_struct *dw_loc_list_ref;

typedef struct GTY(()) deferred_locations_struct
{
  tree variable;
  dw_die_ref die;
} deferred_locations;

DEF_VEC_O(deferred_locations);
DEF_VEC_ALLOC_O(deferred_locations,gc);

static GTY(()) VEC(deferred_locations, gc) *deferred_locations_list;

DEF_VEC_P(dw_die_ref);
DEF_VEC_ALLOC_P(dw_die_ref,heap);

/* Each DIE may have a series of attribute/value pairs.  Values
   can take on several forms.  The forms that are used in this
   implementation are listed below.  */

enum dw_val_class
{
  dw_val_class_addr,
  dw_val_class_offset,
  dw_val_class_loc,
  dw_val_class_loc_list,
  dw_val_class_range_list,
  dw_val_class_const,
  dw_val_class_unsigned_const,
  dw_val_class_const_double,
  dw_val_class_vec,
  dw_val_class_flag,
  dw_val_class_die_ref,
  dw_val_class_fde_ref,
  dw_val_class_lbl_id,
  dw_val_class_lineptr,
  dw_val_class_str,
  dw_val_class_macptr,
  dw_val_class_file,
  dw_val_class_data8,
  dw_val_class_decl_ref,
  dw_val_class_vms_delta
};

/* Describe a floating point constant value, or a vector constant value.  */

typedef struct GTY(()) dw_vec_struct {
  unsigned char * GTY((length ("%h.length"))) array;
  unsigned length;
  unsigned elt_size;
}
dw_vec_const;

/* The dw_val_node describes an attribute's value, as it is
   represented internally.  */

typedef struct GTY(()) dw_val_struct {
  enum dw_val_class val_class;
  union dw_val_struct_union
    {
      rtx GTY ((tag ("dw_val_class_addr"))) val_addr;
      unsigned HOST_WIDE_INT GTY ((tag ("dw_val_class_offset"))) val_offset;
      dw_loc_list_ref GTY ((tag ("dw_val_class_loc_list"))) val_loc_list;
      dw_loc_descr_ref GTY ((tag ("dw_val_class_loc"))) val_loc;
      HOST_WIDE_INT GTY ((default)) val_int;
      unsigned HOST_WIDE_INT GTY ((tag ("dw_val_class_unsigned_const"))) val_unsigned;
      double_int GTY ((tag ("dw_val_class_const_double"))) val_double;
      dw_vec_const GTY ((tag ("dw_val_class_vec"))) val_vec;
      struct dw_val_die_union
        {
          dw_die_ref die;
          int external;
        } GTY ((tag ("dw_val_class_die_ref"))) val_die_ref;
      unsigned GTY ((tag ("dw_val_class_fde_ref"))) val_fde_index;
      struct indirect_string_node * GTY ((tag ("dw_val_class_str"))) val_str;
      char * GTY ((tag ("dw_val_class_lbl_id"))) val_lbl_id;
      unsigned char GTY ((tag ("dw_val_class_flag"))) val_flag;
      struct dwarf_file_data * GTY ((tag ("dw_val_class_file"))) val_file;
      unsigned char GTY ((tag ("dw_val_class_data8"))) val_data8[8];
      tree GTY ((tag ("dw_val_class_decl_ref"))) val_decl_ref;
      struct dw_val_vms_delta_union
        {
          char * lbl1;
          char * lbl2;
        } GTY ((tag ("dw_val_class_vms_delta"))) val_vms_delta;
    }
  GTY ((desc ("%1.val_class"))) v;
}
dw_val_node;

/* Locations in memory are described using a sequence of stack machine
   operations.  */

typedef struct GTY(()) dw_loc_descr_struct {
  dw_loc_descr_ref dw_loc_next;
  ENUM_BITFIELD (dwarf_location_atom) dw_loc_opc : 8;
  /* Used to distinguish DW_OP_addr with a direct symbol relocation
     from DW_OP_addr with a dtp-relative symbol relocation.  */
  unsigned int dtprel : 1;
  int dw_loc_addr;
  dw_val_node dw_loc_oprnd1;
  dw_val_node dw_loc_oprnd2;
}
dw_loc_descr_node;

/* Location lists are ranges + location descriptions for that range,
   so you can track variables that are in different places over
   their entire life.  */
typedef struct GTY(()) dw_loc_list_struct {
  dw_loc_list_ref dw_loc_next;
  const char *begin; /* Label for begin address of range */
  const char *end;  /* Label for end address of range */
  char *ll_symbol; /* Label for beginning of location list.
                      Only on head of list */
  const char *section; /* Section this loclist is relative to */
  dw_loc_descr_ref expr;
  hashval_t hash;
  bool emitted;
} dw_loc_list_node;

static dw_loc_descr_ref int_loc_descriptor (HOST_WIDE_INT);

/* Convert a DWARF stack opcode into its string name.  */

static const char *
dwarf_stack_op_name (unsigned int op)
{
  switch (op)
    {
    case DW_OP_addr:
      return "DW_OP_addr";
    case DW_OP_deref:
      return "DW_OP_deref";
    case DW_OP_const1u:
      return "DW_OP_const1u";
    case DW_OP_const1s:
      return "DW_OP_const1s";
    case DW_OP_const2u:
      return "DW_OP_const2u";
    case DW_OP_const2s:
      return "DW_OP_const2s";
    case DW_OP_const4u:
      return "DW_OP_const4u";
    case DW_OP_const4s:
      return "DW_OP_const4s";
    case DW_OP_const8u:
      return "DW_OP_const8u";
    case DW_OP_const8s:
      return "DW_OP_const8s";
    case DW_OP_constu:
      return "DW_OP_constu";
    case DW_OP_consts:
      return "DW_OP_consts";
    case DW_OP_dup:
      return "DW_OP_dup";
    case DW_OP_drop:
      return "DW_OP_drop";
    case DW_OP_over:
      return "DW_OP_over";
    case DW_OP_pick:
      return "DW_OP_pick";
    case DW_OP_swap:
      return "DW_OP_swap";
    case DW_OP_rot:
      return "DW_OP_rot";
    case DW_OP_xderef:
      return "DW_OP_xderef";
    case DW_OP_abs:
      return "DW_OP_abs";
    case DW_OP_and:
      return "DW_OP_and";
    case DW_OP_div:
      return "DW_OP_div";
    case DW_OP_minus:
      return "DW_OP_minus";
    case DW_OP_mod:
      return "DW_OP_mod";
    case DW_OP_mul:
      return "DW_OP_mul";
    case DW_OP_neg:
      return "DW_OP_neg";
    case DW_OP_not:
      return "DW_OP_not";
    case DW_OP_or:
      return "DW_OP_or";
    case DW_OP_plus:
      return "DW_OP_plus";
    case DW_OP_plus_uconst:
      return "DW_OP_plus_uconst";
    case DW_OP_shl:
      return "DW_OP_shl";
    case DW_OP_shr:
      return "DW_OP_shr";
    case DW_OP_shra:
      return "DW_OP_shra";
    case DW_OP_xor:
      return "DW_OP_xor";
    case DW_OP_bra:
      return "DW_OP_bra";
    case DW_OP_eq:
      return "DW_OP_eq";
    case DW_OP_ge:
      return "DW_OP_ge";
    case DW_OP_gt:
      return "DW_OP_gt";
    case DW_OP_le:
      return "DW_OP_le";
    case DW_OP_lt:
      return "DW_OP_lt";
    case DW_OP_ne:
      return "DW_OP_ne";
    case DW_OP_skip:
      return "DW_OP_skip";
    case DW_OP_lit0:
      return "DW_OP_lit0";
    case DW_OP_lit1:
      return "DW_OP_lit1";
    case DW_OP_lit2:
      return "DW_OP_lit2";
    case DW_OP_lit3:
      return "DW_OP_lit3";
    case DW_OP_lit4:
      return "DW_OP_lit4";
    case DW_OP_lit5:
      return "DW_OP_lit5";
    case DW_OP_lit6:
      return "DW_OP_lit6";
    case DW_OP_lit7:
      return "DW_OP_lit7";
    case DW_OP_lit8:
      return "DW_OP_lit8";
    case DW_OP_lit9:
      return "DW_OP_lit9";
    case DW_OP_lit10:
      return "DW_OP_lit10";
    case DW_OP_lit11:
      return "DW_OP_lit11";
    case DW_OP_lit12:
      return "DW_OP_lit12";
    case DW_OP_lit13:
      return "DW_OP_lit13";
    case DW_OP_lit14:
      return "DW_OP_lit14";
    case DW_OP_lit15:
      return "DW_OP_lit15";
    case DW_OP_lit16:
      return "DW_OP_lit16";
    case DW_OP_lit17:
      return "DW_OP_lit17";
    case DW_OP_lit18:
      return "DW_OP_lit18";
    case DW_OP_lit19:
      return "DW_OP_lit19";
    case DW_OP_lit20:
      return "DW_OP_lit20";
    case DW_OP_lit21:
      return "DW_OP_lit21";
    case DW_OP_lit22:
      return "DW_OP_lit22";
    case DW_OP_lit23:
      return "DW_OP_lit23";
    case DW_OP_lit24:
      return "DW_OP_lit24";
    case DW_OP_lit25:
      return "DW_OP_lit25";
    case DW_OP_lit26:
      return "DW_OP_lit26";
    case DW_OP_lit27:
      return "DW_OP_lit27";
    case DW_OP_lit28:
      return "DW_OP_lit28";
    case DW_OP_lit29:
      return "DW_OP_lit29";
    case DW_OP_lit30:
      return "DW_OP_lit30";
    case DW_OP_lit31:
      return "DW_OP_lit31";
    case DW_OP_reg0:
      return "DW_OP_reg0";
    case DW_OP_reg1:
      return "DW_OP_reg1";
    case DW_OP_reg2:
      return "DW_OP_reg2";
    case DW_OP_reg3:
      return "DW_OP_reg3";
    case DW_OP_reg4:
      return "DW_OP_reg4";
    case DW_OP_reg5:
      return "DW_OP_reg5";
    case DW_OP_reg6:
      return "DW_OP_reg6";
    case DW_OP_reg7:
      return "DW_OP_reg7";
    case DW_OP_reg8:
      return "DW_OP_reg8";
    case DW_OP_reg9:
      return "DW_OP_reg9";
    case DW_OP_reg10:
      return "DW_OP_reg10";
    case DW_OP_reg11:
      return "DW_OP_reg11";
    case DW_OP_reg12:
      return "DW_OP_reg12";
    case DW_OP_reg13:
      return "DW_OP_reg13";
    case DW_OP_reg14:
      return "DW_OP_reg14";
    case DW_OP_reg15:
      return "DW_OP_reg15";
    case DW_OP_reg16:
      return "DW_OP_reg16";
    case DW_OP_reg17:
      return "DW_OP_reg17";
    case DW_OP_reg18:
      return "DW_OP_reg18";
    case DW_OP_reg19:
      return "DW_OP_reg19";
    case DW_OP_reg20:
      return "DW_OP_reg20";
    case DW_OP_reg21:
      return "DW_OP_reg21";
    case DW_OP_reg22:
      return "DW_OP_reg22";
    case DW_OP_reg23:
      return "DW_OP_reg23";
    case DW_OP_reg24:
      return "DW_OP_reg24";
    case DW_OP_reg25:
      return "DW_OP_reg25";
    case DW_OP_reg26:
      return "DW_OP_reg26";
    case DW_OP_reg27:
      return "DW_OP_reg27";
    case DW_OP_reg28:
      return "DW_OP_reg28";
    case DW_OP_reg29:
      return "DW_OP_reg29";
    case DW_OP_reg30:
      return "DW_OP_reg30";
    case DW_OP_reg31:
      return "DW_OP_reg31";
    case DW_OP_breg0:
      return "DW_OP_breg0";
    case DW_OP_breg1:
      return "DW_OP_breg1";
    case DW_OP_breg2:
      return "DW_OP_breg2";
    case DW_OP_breg3:
      return "DW_OP_breg3";
    case DW_OP_breg4:
      return "DW_OP_breg4";
    case DW_OP_breg5:
      return "DW_OP_breg5";
    case DW_OP_breg6:
      return "DW_OP_breg6";
    case DW_OP_breg7:
      return "DW_OP_breg7";
    case DW_OP_breg8:
      return "DW_OP_breg8";
    case DW_OP_breg9:
      return "DW_OP_breg9";
    case DW_OP_breg10:
      return "DW_OP_breg10";
    case DW_OP_breg11:
      return "DW_OP_breg11";
    case DW_OP_breg12:
      return "DW_OP_breg12";
    case DW_OP_breg13:
      return "DW_OP_breg13";
    case DW_OP_breg14:
      return "DW_OP_breg14";
    case DW_OP_breg15:
      return "DW_OP_breg15";
    case DW_OP_breg16:
      return "DW_OP_breg16";
    case DW_OP_breg17:
      return "DW_OP_breg17";
    case DW_OP_breg18:
      return "DW_OP_breg18";
    case DW_OP_breg19:
      return "DW_OP_breg19";
    case DW_OP_breg20:
      return "DW_OP_breg20";
    case DW_OP_breg21:
      return "DW_OP_breg21";
    case DW_OP_breg22:
      return "DW_OP_breg22";
    case DW_OP_breg23:
      return "DW_OP_breg23";
    case DW_OP_breg24:
      return "DW_OP_breg24";
    case DW_OP_breg25:
      return "DW_OP_breg25";
    case DW_OP_breg26:
      return "DW_OP_breg26";
    case DW_OP_breg27:
      return "DW_OP_breg27";
    case DW_OP_breg28:
      return "DW_OP_breg28";
    case DW_OP_breg29:
      return "DW_OP_breg29";
    case DW_OP_breg30:
      return "DW_OP_breg30";
    case DW_OP_breg31:
      return "DW_OP_breg31";
    case DW_OP_regx:
      return "DW_OP_regx";
    case DW_OP_fbreg:
      return "DW_OP_fbreg";
    case DW_OP_bregx:
      return "DW_OP_bregx";
    case DW_OP_piece:
      return "DW_OP_piece";
    case DW_OP_deref_size:
      return "DW_OP_deref_size";
    case DW_OP_xderef_size:
      return "DW_OP_xderef_size";
    case DW_OP_nop:
      return "DW_OP_nop";

    case DW_OP_push_object_address:
      return "DW_OP_push_object_address";
    case DW_OP_call2:
      return "DW_OP_call2";
    case DW_OP_call4:
      return "DW_OP_call4";
    case DW_OP_call_ref:
      return "DW_OP_call_ref";
    case DW_OP_implicit_value:
      return "DW_OP_implicit_value";
    case DW_OP_stack_value:
      return "DW_OP_stack_value";
    case DW_OP_form_tls_address:
      return "DW_OP_form_tls_address";
    case DW_OP_call_frame_cfa:
      return "DW_OP_call_frame_cfa";
    case DW_OP_bit_piece:
      return "DW_OP_bit_piece";

    case DW_OP_GNU_push_tls_address:
      return "DW_OP_GNU_push_tls_address";
    case DW_OP_GNU_uninit:
      return "DW_OP_GNU_uninit";
    case DW_OP_GNU_encoded_addr:
      return "DW_OP_GNU_encoded_addr";
    case DW_OP_GNU_implicit_pointer:
      return "DW_OP_GNU_implicit_pointer";

    default:
      return "OP_<unknown>";
    }
}

/* Return a pointer to a newly allocated location description.  Location
   descriptions are simple expression terms that can be strung
   together to form more complicated location (address) descriptions.  */

static inline dw_loc_descr_ref
new_loc_descr (enum dwarf_location_atom op, unsigned HOST_WIDE_INT oprnd1,
               unsigned HOST_WIDE_INT oprnd2)
{
  dw_loc_descr_ref descr = ggc_alloc_cleared_dw_loc_descr_node ();

  descr->dw_loc_opc = op;
  descr->dw_loc_oprnd1.val_class = dw_val_class_unsigned_const;
  descr->dw_loc_oprnd1.v.val_unsigned = oprnd1;
  descr->dw_loc_oprnd2.val_class = dw_val_class_unsigned_const;
  descr->dw_loc_oprnd2.v.val_unsigned = oprnd2;

  return descr;
}

/* Return a pointer to a newly allocated location description for
   REG and OFFSET.  */

static inline dw_loc_descr_ref
new_reg_loc_descr (unsigned int reg,  unsigned HOST_WIDE_INT offset)
{
  if (reg <= 31)
    return new_loc_descr ((enum dwarf_location_atom) (DW_OP_breg0 + reg),
                          offset, 0);
  else
    return new_loc_descr (DW_OP_bregx, reg, offset);
}

/* Add a location description term to a location description expression.  */

static inline void
add_loc_descr (dw_loc_descr_ref *list_head, dw_loc_descr_ref descr)
{
  dw_loc_descr_ref *d;

  /* Find the end of the chain.  */
  for (d = list_head; (*d) != NULL; d = &(*d)->dw_loc_next)
    ;

  *d = descr;
}

/* Add a constant OFFSET to a location expression.  */

static void
loc_descr_plus_const (dw_loc_descr_ref *list_head, HOST_WIDE_INT offset)
{
  dw_loc_descr_ref loc;
  HOST_WIDE_INT *p;

  gcc_assert (*list_head != NULL);

  if (!offset)
    return;

  /* Find the end of the chain.  */
  for (loc = *list_head; loc->dw_loc_next != NULL; loc = loc->dw_loc_next)
    ;

  p = NULL;
  if (loc->dw_loc_opc == DW_OP_fbreg
      || (loc->dw_loc_opc >= DW_OP_breg0 && loc->dw_loc_opc <= DW_OP_breg31))
    p = &loc->dw_loc_oprnd1.v.val_int;
  else if (loc->dw_loc_opc == DW_OP_bregx)
    p = &loc->dw_loc_oprnd2.v.val_int;

  /* If the last operation is fbreg, breg{0..31,x}, optimize by adjusting its
     offset.  Don't optimize if an signed integer overflow would happen.  */
  if (p != NULL
      && ((offset > 0 && *p <= INTTYPE_MAXIMUM (HOST_WIDE_INT) - offset)
          || (offset < 0 && *p >= INTTYPE_MINIMUM (HOST_WIDE_INT) - offset)))
    *p += offset;

  else if (offset > 0)
    loc->dw_loc_next = new_loc_descr (DW_OP_plus_uconst, offset, 0);

  else
    {
      loc->dw_loc_next = int_loc_descriptor (-offset);
      add_loc_descr (&loc->dw_loc_next, new_loc_descr (DW_OP_minus, 0, 0));
    }
}

/* Add a constant OFFSET to a location list.  */

static void
loc_list_plus_const (dw_loc_list_ref list_head, HOST_WIDE_INT offset)
{
  dw_loc_list_ref d;
  for (d = list_head; d != NULL; d = d->dw_loc_next)
    loc_descr_plus_const (&d->expr, offset);
}

#define DWARF_REF_SIZE  \
  (dwarf_version == 2 ? DWARF2_ADDR_SIZE : DWARF_OFFSET_SIZE)

/* Return the size of a location descriptor.  */

static unsigned long
size_of_loc_descr (dw_loc_descr_ref loc)
{
  unsigned long size = 1;

  switch (loc->dw_loc_opc)
    {
    case DW_OP_addr:
      size += DWARF2_ADDR_SIZE;
      break;
    case DW_OP_const1u:
    case DW_OP_const1s:
      size += 1;
      break;
    case DW_OP_const2u:
    case DW_OP_const2s:
      size += 2;
      break;
    case DW_OP_const4u:
    case DW_OP_const4s:
      size += 4;
      break;
    case DW_OP_const8u:
    case DW_OP_const8s:
      size += 8;
      break;
    case DW_OP_constu:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_consts:
      size += size_of_sleb128 (loc->dw_loc_oprnd1.v.val_int);
      break;
    case DW_OP_pick:
      size += 1;
      break;
    case DW_OP_plus_uconst:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_skip:
    case DW_OP_bra:
      size += 2;
      break;
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
      size += size_of_sleb128 (loc->dw_loc_oprnd1.v.val_int);
      break;
    case DW_OP_regx:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_fbreg:
      size += size_of_sleb128 (loc->dw_loc_oprnd1.v.val_int);
      break;
    case DW_OP_bregx:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      size += size_of_sleb128 (loc->dw_loc_oprnd2.v.val_int);
      break;
    case DW_OP_piece:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_bit_piece:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      size += size_of_uleb128 (loc->dw_loc_oprnd2.v.val_unsigned);
      break;
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      size += 1;
      break;
    case DW_OP_call2:
      size += 2;
      break;
    case DW_OP_call4:
      size += 4;
      break;
    case DW_OP_call_ref:
      size += DWARF_REF_SIZE;
      break;
    case DW_OP_implicit_value:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned)
              + loc->dw_loc_oprnd1.v.val_unsigned;
      break;
    case DW_OP_GNU_implicit_pointer:
      size += DWARF_REF_SIZE + size_of_sleb128 (loc->dw_loc_oprnd2.v.val_int);
      break;
    default:
      break;
    }

  return size;
}

/* Return the size of a series of location descriptors.  */

static unsigned long
size_of_locs (dw_loc_descr_ref loc)
{
  dw_loc_descr_ref l;
  unsigned long size;

  /* If there are no skip or bra opcodes, don't fill in the dw_loc_addr
     field, to avoid writing to a PCH file.  */
  for (size = 0, l = loc; l != NULL; l = l->dw_loc_next)
    {
      if (l->dw_loc_opc == DW_OP_skip || l->dw_loc_opc == DW_OP_bra)
        break;
      size += size_of_loc_descr (l);
    }
  if (! l)
    return size;

  for (size = 0, l = loc; l != NULL; l = l->dw_loc_next)
    {
      l->dw_loc_addr = size;
      size += size_of_loc_descr (l);
    }

  return size;
}

static HOST_WIDE_INT extract_int (const unsigned char *, unsigned);
static void get_ref_die_offset_label (char *, dw_die_ref);

/* Output location description stack opcode's operands (if any).  */

static void
output_loc_operands (dw_loc_descr_ref loc)
{
  dw_val_ref val1 = &loc->dw_loc_oprnd1;
  dw_val_ref val2 = &loc->dw_loc_oprnd2;

  switch (loc->dw_loc_opc)
    {
#ifdef DWARF2_DEBUGGING_INFO
    case DW_OP_const2u:
    case DW_OP_const2s:
      dw2_asm_output_data (2, val1->v.val_int, NULL);
      break;
    case DW_OP_const4u:
      if (loc->dtprel)
        {
          gcc_assert (targetm.asm_out.output_dwarf_dtprel);
          targetm.asm_out.output_dwarf_dtprel (asm_out_file, 4,
                                               val1->v.val_addr);
          fputc ('\n', asm_out_file);
          break;
        }
      /* FALLTHRU */
    case DW_OP_const4s:
      dw2_asm_output_data (4, val1->v.val_int, NULL);
      break;
    case DW_OP_const8u:
      if (loc->dtprel)
        {
          gcc_assert (targetm.asm_out.output_dwarf_dtprel);
          targetm.asm_out.output_dwarf_dtprel (asm_out_file, 8,
                                               val1->v.val_addr);
          fputc ('\n', asm_out_file);
          break;
        }
      /* FALLTHRU */
    case DW_OP_const8s:
      gcc_assert (HOST_BITS_PER_WIDE_INT >= 64);
      dw2_asm_output_data (8, val1->v.val_int, NULL);
      break;
    case DW_OP_skip:
    case DW_OP_bra:
      {
        int offset;

        gcc_assert (val1->val_class == dw_val_class_loc);
        offset = val1->v.val_loc->dw_loc_addr - (loc->dw_loc_addr + 3);

        dw2_asm_output_data (2, offset, NULL);
      }
      break;
    case DW_OP_implicit_value:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      switch (val2->val_class)
        {
        case dw_val_class_const:
          dw2_asm_output_data (val1->v.val_unsigned, val2->v.val_int, NULL);
          break;
        case dw_val_class_vec:
          {
            unsigned int elt_size = val2->v.val_vec.elt_size;
            unsigned int len = val2->v.val_vec.length;
            unsigned int i;
            unsigned char *p;

            if (elt_size > sizeof (HOST_WIDE_INT))
              {
                elt_size /= 2;
                len *= 2;
              }
            for (i = 0, p = val2->v.val_vec.array;
                 i < len;
                 i++, p += elt_size)
              dw2_asm_output_data (elt_size, extract_int (p, elt_size),
                                   "fp or vector constant word %u", i);
          }
          break;
        case dw_val_class_const_double:
          {
            unsigned HOST_WIDE_INT first, second;

            if (WORDS_BIG_ENDIAN)
              {
                first = val2->v.val_double.high;
                second = val2->v.val_double.low;
              }
            else
              {
                first = val2->v.val_double.low;
                second = val2->v.val_double.high;
              }
            dw2_asm_output_data (HOST_BITS_PER_WIDE_INT / HOST_BITS_PER_CHAR,
                                 first, NULL);
            dw2_asm_output_data (HOST_BITS_PER_WIDE_INT / HOST_BITS_PER_CHAR,
                                 second, NULL);
          }
          break;
        case dw_val_class_addr:
          gcc_assert (val1->v.val_unsigned == DWARF2_ADDR_SIZE);
          dw2_asm_output_addr_rtx (DWARF2_ADDR_SIZE, val2->v.val_addr, NULL);
          break;
        default:
          gcc_unreachable ();
        }
      break;
#else
    case DW_OP_const2u:
    case DW_OP_const2s:
    case DW_OP_const4u:
    case DW_OP_const4s:
    case DW_OP_const8u:
    case DW_OP_const8s:
    case DW_OP_skip:
    case DW_OP_bra:
    case DW_OP_implicit_value:
      /* We currently don't make any attempt to make sure these are
         aligned properly like we do for the main unwind info, so
         don't support emitting things larger than a byte if we're
         only doing unwinding.  */
      gcc_unreachable ();
#endif
    case DW_OP_const1u:
    case DW_OP_const1s:
      dw2_asm_output_data (1, val1->v.val_int, NULL);
      break;
    case DW_OP_constu:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_consts:
      dw2_asm_output_data_sleb128 (val1->v.val_int, NULL);
      break;
    case DW_OP_pick:
      dw2_asm_output_data (1, val1->v.val_int, NULL);
      break;
    case DW_OP_plus_uconst:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
      dw2_asm_output_data_sleb128 (val1->v.val_int, NULL);
      break;
    case DW_OP_regx:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_fbreg:
      dw2_asm_output_data_sleb128 (val1->v.val_int, NULL);
      break;
    case DW_OP_bregx:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      dw2_asm_output_data_sleb128 (val2->v.val_int, NULL);
      break;
    case DW_OP_piece:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_bit_piece:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      dw2_asm_output_data_uleb128 (val2->v.val_unsigned, NULL);
      break;
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      dw2_asm_output_data (1, val1->v.val_int, NULL);
      break;

    case DW_OP_addr:
      if (loc->dtprel)
        {
          if (targetm.asm_out.output_dwarf_dtprel)
            {
              targetm.asm_out.output_dwarf_dtprel (asm_out_file,
                                                   DWARF2_ADDR_SIZE,
                                                   val1->v.val_addr);
              fputc ('\n', asm_out_file);
            }
          else
            gcc_unreachable ();
        }
      else
        {
#ifdef DWARF2_DEBUGGING_INFO
          dw2_asm_output_addr_rtx (DWARF2_ADDR_SIZE, val1->v.val_addr, NULL);
#else
          gcc_unreachable ();
#endif
        }
      break;

    case DW_OP_GNU_implicit_pointer:
      {
        char label[MAX_ARTIFICIAL_LABEL_BYTES
                   + HOST_BITS_PER_WIDE_INT / 2 + 2];
        gcc_assert (val1->val_class == dw_val_class_die_ref);
        get_ref_die_offset_label (label, val1->v.val_die_ref.die);
        dw2_asm_output_offset (DWARF_REF_SIZE, label, debug_info_section, NULL);
        dw2_asm_output_data_sleb128 (val2->v.val_int, NULL);
      }
      break;

    default:
      /* Other codes have no operands.  */
      break;
    }
}

/* Output a sequence of location operations.  */

static void
output_loc_sequence (dw_loc_descr_ref loc)
{
  for (; loc != NULL; loc = loc->dw_loc_next)
    {
      /* Output the opcode.  */
      dw2_asm_output_data (1, loc->dw_loc_opc,
                           "%s", dwarf_stack_op_name (loc->dw_loc_opc));

      /* Output the operand(s) (if any).  */
      output_loc_operands (loc);
    }
}

/* Output location description stack opcode's operands (if any).
   The output is single bytes on a line, suitable for .cfi_escape.  */

static void
output_loc_operands_raw (dw_loc_descr_ref loc)
{
  dw_val_ref val1 = &loc->dw_loc_oprnd1;
  dw_val_ref val2 = &loc->dw_loc_oprnd2;

  switch (loc->dw_loc_opc)
    {
    case DW_OP_addr:
    case DW_OP_implicit_value:
      /* We cannot output addresses in .cfi_escape, only bytes.  */
      gcc_unreachable ();

    case DW_OP_const1u:
    case DW_OP_const1s:
    case DW_OP_pick:
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      fputc (',', asm_out_file);
      dw2_asm_output_data_raw (1, val1->v.val_int);
      break;

    case DW_OP_const2u:
    case DW_OP_const2s:
      fputc (',', asm_out_file);
      dw2_asm_output_data_raw (2, val1->v.val_int);
      break;

    case DW_OP_const4u:
    case DW_OP_const4s:
      fputc (',', asm_out_file);
      dw2_asm_output_data_raw (4, val1->v.val_int);
      break;

    case DW_OP_const8u:
    case DW_OP_const8s:
      gcc_assert (HOST_BITS_PER_WIDE_INT >= 64);
      fputc (',', asm_out_file);
      dw2_asm_output_data_raw (8, val1->v.val_int);
      break;

    case DW_OP_skip:
    case DW_OP_bra:
      {
        int offset;

        gcc_assert (val1->val_class == dw_val_class_loc);
        offset = val1->v.val_loc->dw_loc_addr - (loc->dw_loc_addr + 3);

        fputc (',', asm_out_file);
        dw2_asm_output_data_raw (2, offset);
      }
      break;

    case DW_OP_constu:
    case DW_OP_plus_uconst:
    case DW_OP_regx:
    case DW_OP_piece:
      fputc (',', asm_out_file);
      dw2_asm_output_data_uleb128_raw (val1->v.val_unsigned);
      break;

    case DW_OP_bit_piece:
      fputc (',', asm_out_file);
      dw2_asm_output_data_uleb128_raw (val1->v.val_unsigned);
      dw2_asm_output_data_uleb128_raw (val2->v.val_unsigned);
      break;

    case DW_OP_consts:
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
    case DW_OP_fbreg:
      fputc (',', asm_out_file);
      dw2_asm_output_data_sleb128_raw (val1->v.val_int);
      break;

    case DW_OP_bregx:
      fputc (',', asm_out_file);
      dw2_asm_output_data_uleb128_raw (val1->v.val_unsigned);
      fputc (',', asm_out_file);
      dw2_asm_output_data_sleb128_raw (val2->v.val_int);
      break;

    case DW_OP_GNU_implicit_pointer:
      gcc_unreachable ();
      break;

    default:
      /* Other codes have no operands.  */
      break;
    }
}

static void
output_loc_sequence_raw (dw_loc_descr_ref loc)
{
  while (1)
    {
      /* Output the opcode.  */
      fprintf (asm_out_file, "%#x", loc->dw_loc_opc);
      output_loc_operands_raw (loc);

      if (!loc->dw_loc_next)
        break;
      loc = loc->dw_loc_next;

      fputc (',', asm_out_file);
    }
}

/* This routine will generate the correct assembly data for a location
   description based on a cfi entry with a complex address.  */

static void
output_cfa_loc (dw_cfi_ref cfi)
{
  dw_loc_descr_ref loc;
  unsigned long size;

  if (cfi->dw_cfi_opc == DW_CFA_expression)
    {
      dw2_asm_output_data (1, cfi->dw_cfi_oprnd1.dw_cfi_reg_num, NULL);
      loc = cfi->dw_cfi_oprnd2.dw_cfi_loc;
    }
  else
    loc = cfi->dw_cfi_oprnd1.dw_cfi_loc;

  /* Output the size of the block.  */
  size = size_of_locs (loc);
  dw2_asm_output_data_uleb128 (size, NULL);

  /* Now output the operations themselves.  */
  output_loc_sequence (loc);
}

/* Similar, but used for .cfi_escape.  */

static void
output_cfa_loc_raw (dw_cfi_ref cfi)
{
  dw_loc_descr_ref loc;
  unsigned long size;

  if (cfi->dw_cfi_opc == DW_CFA_expression)
    {
      fprintf (asm_out_file, "%#x,", cfi->dw_cfi_oprnd1.dw_cfi_reg_num);
      loc = cfi->dw_cfi_oprnd2.dw_cfi_loc;
    }
  else
    loc = cfi->dw_cfi_oprnd1.dw_cfi_loc;

  /* Output the size of the block.  */
  size = size_of_locs (loc);
  dw2_asm_output_data_uleb128_raw (size);
  fputc (',', asm_out_file);

  /* Now output the operations themselves.  */
  output_loc_sequence_raw (loc);
}

/* This function builds a dwarf location descriptor sequence from a
   dw_cfa_location, adding the given OFFSET to the result of the
   expression.  */

static struct dw_loc_descr_struct *
build_cfa_loc (dw_cfa_location *cfa, HOST_WIDE_INT offset)
{
  struct dw_loc_descr_struct *head, *tmp;

  offset += cfa->offset;

  if (cfa->indirect)
    {
      head = new_reg_loc_descr (cfa->reg, cfa->base_offset);
      head->dw_loc_oprnd1.val_class = dw_val_class_const;
      tmp = new_loc_descr (DW_OP_deref, 0, 0);
      add_loc_descr (&head, tmp);
      if (offset != 0)
        {
          tmp = new_loc_descr (DW_OP_plus_uconst, offset, 0);
          add_loc_descr (&head, tmp);
        }
    }
  else
    head = new_reg_loc_descr (cfa->reg, offset);

  return head;
}

/* This function builds a dwarf location descriptor sequence for
   the address at OFFSET from the CFA when stack is aligned to
   ALIGNMENT byte.  */

static struct dw_loc_descr_struct *
build_cfa_aligned_loc (HOST_WIDE_INT offset, HOST_WIDE_INT alignment)
{
  struct dw_loc_descr_struct *head;
  unsigned int dwarf_fp
    = DWARF_FRAME_REGNUM (HARD_FRAME_POINTER_REGNUM);

 /* When CFA is defined as FP+OFFSET, emulate stack alignment.  */
  if (cfa.reg == HARD_FRAME_POINTER_REGNUM && cfa.indirect == 0)
    {
      head = new_reg_loc_descr (dwarf_fp, 0);
      add_loc_descr (&head, int_loc_descriptor (alignment));
      add_loc_descr (&head, new_loc_descr (DW_OP_and, 0, 0));
      loc_descr_plus_const (&head, offset);
    }
  else
    head = new_reg_loc_descr (dwarf_fp, offset);
  return head;
}

/* This function fills in aa dw_cfa_location structure from a dwarf location
   descriptor sequence.  */

static void
get_cfa_from_loc_descr (dw_cfa_location *cfa, struct dw_loc_descr_struct *loc)
{
  struct dw_loc_descr_struct *ptr;
  cfa->offset = 0;
  cfa->base_offset = 0;
  cfa->indirect = 0;
  cfa->reg = -1;

  for (ptr = loc; ptr != NULL; ptr = ptr->dw_loc_next)
    {
      enum dwarf_location_atom op = ptr->dw_loc_opc;

      switch (op)
        {
        case DW_OP_reg0:
        case DW_OP_reg1:
        case DW_OP_reg2:
        case DW_OP_reg3:
        case DW_OP_reg4:
        case DW_OP_reg5:
        case DW_OP_reg6:
        case DW_OP_reg7:
        case DW_OP_reg8:
        case DW_OP_reg9:
        case DW_OP_reg10:
        case DW_OP_reg11:
        case DW_OP_reg12:
        case DW_OP_reg13:
        case DW_OP_reg14:
        case DW_OP_reg15:
        case DW_OP_reg16:
        case DW_OP_reg17:
        case DW_OP_reg18:
        case DW_OP_reg19:
        case DW_OP_reg20:
        case DW_OP_reg21:
        case DW_OP_reg22:
        case DW_OP_reg23:
        case DW_OP_reg24:
        case DW_OP_reg25:
        case DW_OP_reg26:
        case DW_OP_reg27:
        case DW_OP_reg28:
        case DW_OP_reg29:
        case DW_OP_reg30:
        case DW_OP_reg31:
          cfa->reg = op - DW_OP_reg0;
          break;
        case DW_OP_regx:
          cfa->reg = ptr->dw_loc_oprnd1.v.val_int;
          break;
        case DW_OP_breg0:
        case DW_OP_breg1:
        case DW_OP_breg2:
        case DW_OP_breg3:
        case DW_OP_breg4:
        case DW_OP_breg5:
        case DW_OP_breg6:
        case DW_OP_breg7:
        case DW_OP_breg8:
        case DW_OP_breg9:
        case DW_OP_breg10:
        case DW_OP_breg11:
        case DW_OP_breg12:
        case DW_OP_breg13:
        case DW_OP_breg14:
        case DW_OP_breg15:
        case DW_OP_breg16:
        case DW_OP_breg17:
        case DW_OP_breg18:
        case DW_OP_breg19:
        case DW_OP_breg20:
        case DW_OP_breg21:
        case DW_OP_breg22:
        case DW_OP_breg23:
        case DW_OP_breg24:
        case DW_OP_breg25:
        case DW_OP_breg26:
        case DW_OP_breg27:
        case DW_OP_breg28:
        case DW_OP_breg29:
        case DW_OP_breg30:
        case DW_OP_breg31:
          cfa->reg = op - DW_OP_breg0;
          cfa->base_offset = ptr->dw_loc_oprnd1.v.val_int;
          break;
        case DW_OP_bregx:
          cfa->reg = ptr->dw_loc_oprnd1.v.val_int;
          cfa->base_offset = ptr->dw_loc_oprnd2.v.val_int;
          break;
        case DW_OP_deref:
          cfa->indirect = 1;
          break;
        case DW_OP_plus_uconst:
          cfa->offset = ptr->dw_loc_oprnd1.v.val_unsigned;
          break;
        default:
          internal_error ("DW_LOC_OP %s not implemented",
                          dwarf_stack_op_name (ptr->dw_loc_opc));
        }
    }
}
\f
/* And now, the support for symbolic debugging information.  */

/* .debug_str support.  */
static int output_indirect_string (void **, void *);

static void dwarf2out_init (const char *);
static void dwarf2out_finish (const char *);
static void dwarf2out_assembly_start (void);
static void dwarf2out_define (unsigned int, const char *);
static void dwarf2out_undef (unsigned int, const char *);
static void dwarf2out_start_source_file (unsigned, const char *);
static void dwarf2out_end_source_file (unsigned);
static void dwarf2out_function_decl (tree);
static void dwarf2out_begin_block (unsigned, unsigned);
static void dwarf2out_end_block (unsigned, unsigned);
static bool dwarf2out_ignore_block (const_tree);
static void dwarf2out_global_decl (tree);
static void dwarf2out_type_decl (tree, int);
static void dwarf2out_imported_module_or_decl (tree, tree, tree, bool);
static void dwarf2out_imported_module_or_decl_1 (tree, tree, tree,
                                                 dw_die_ref);
static void dwarf2out_abstract_function (tree);
static void dwarf2out_var_location (rtx);
static void dwarf2out_direct_call (tree);
static void dwarf2out_virtual_call_token (tree, int);
static void dwarf2out_copy_call_info (rtx, rtx);
static void dwarf2out_virtual_call (int);
static void dwarf2out_begin_function (tree);
static void dwarf2out_set_name (tree, tree);

/* The debug hooks structure.  */

const struct gcc_debug_hooks dwarf2_debug_hooks =
{
  dwarf2out_init,
  dwarf2out_finish,
  dwarf2out_assembly_start,
  dwarf2out_define,
  dwarf2out_undef,
  dwarf2out_start_source_file,
  dwarf2out_end_source_file,
  dwarf2out_begin_block,
  dwarf2out_end_block,
  dwarf2out_ignore_block,
  dwarf2out_source_line,
  dwarf2out_begin_prologue,
#if VMS_DEBUGGING_INFO
  dwarf2out_vms_end_prologue,
  dwarf2out_vms_begin_epilogue,
#else
  debug_nothing_int_charstar,
  debug_nothing_int_charstar,
#endif
  dwarf2out_end_epilogue,
  dwarf2out_begin_function,
  debug_nothing_int,            /* end_function */
  dwarf2out_function_decl,      /* function_decl */
  dwarf2out_global_decl,
  dwarf2out_type_decl,          /* type_decl */
  dwarf2out_imported_module_or_decl,
  debug_nothing_tree,           /* deferred_inline_function */
  /* The DWARF 2 backend tries to reduce debugging bloat by not
     emitting the abstract description of inline functions until
     something tries to reference them.  */
  dwarf2out_abstract_function,  /* outlining_inline_function */
  debug_nothing_rtx,            /* label */
  debug_nothing_int,            /* handle_pch */
  dwarf2out_var_location,
  dwarf2out_switch_text_section,
  dwarf2out_direct_call,
  dwarf2out_virtual_call_token,
  dwarf2out_copy_call_info,
  dwarf2out_virtual_call,
  dwarf2out_set_name,
  1,                            /* start_end_main_source_file */
  TYPE_SYMTAB_IS_DIE            /* tree_type_symtab_field */
};
\f
/* NOTE: In the comments in this file, many references are made to
   "Debugging Information Entries".  This term is abbreviated as `DIE'
   throughout the remainder of this file.  */

/* An internal representation of the DWARF output is built, and then
   walked to generate the DWARF debugging info.  The walk of the internal
   representation is done after the entire program has been compiled.
   The types below are used to describe the internal representation.  */

/* Various DIE's use offsets relative to the beginning of the
   .debug_info section to refer to each other.  */

typedef long int dw_offset;

/* Define typedefs here to avoid circular dependencies.  */

typedef struct dw_attr_struct *dw_attr_ref;
typedef struct dw_line_info_struct *dw_line_info_ref;
typedef struct dw_separate_line_info_struct *dw_separate_line_info_ref;
typedef struct pubname_struct *pubname_ref;
typedef struct dw_ranges_struct *dw_ranges_ref;
typedef struct dw_ranges_by_label_struct *dw_ranges_by_label_ref;
typedef struct comdat_type_struct *comdat_type_node_ref;

/* Each entry in the line_info_table maintains the file and
   line number associated with the label generated for that
   entry.  The label gives the PC value associated with
   the line number entry.  */

typedef struct GTY(()) dw_line_info_struct {
  unsigned long dw_file_num;
  unsigned long dw_line_num;
}
dw_line_info_entry;

/* Line information for functions in separate sections; each one gets its
   own sequence.  */
typedef struct GTY(()) dw_separate_line_info_struct {
  unsigned long dw_file_num;
  unsigned long dw_line_num;
  unsigned long function;
}
dw_separate_line_info_entry;

/* Each DIE attribute has a field specifying the attribute kind,
   a link to the next attribute in the chain, and an attribute value.
   Attributes are typically linked below the DIE they modify.  */

typedef struct GTY(()) dw_attr_struct {
  enum dwarf_attribute dw_attr;
  dw_val_node dw_attr_val;
}
dw_attr_node;

DEF_VEC_O(dw_attr_node);
DEF_VEC_ALLOC_O(dw_attr_node,gc);

/* The Debugging Information Entry (DIE) structure.  DIEs form a tree.
   The children of each node form a circular list linked by
   die_sib.  die_child points to the node *before* the "first" child node.  */

typedef struct GTY((chain_circular ("%h.die_sib"))) die_struct {
  union die_symbol_or_type_node
    {
      char * GTY ((tag ("0"))) die_symbol;
      comdat_type_node_ref GTY ((tag ("1"))) die_type_node;
    }
  GTY ((desc ("dwarf_version >= 4"))) die_id;
  VEC(dw_attr_node,gc) * die_attr;
  dw_die_ref die_parent;
  dw_die_ref die_child;
  dw_die_ref die_sib;
  dw_die_ref die_definition; /* ref from a specification to its definition */
  dw_offset die_offset;
  unsigned long die_abbrev;
  int die_mark;
  /* Die is used and must not be pruned as unused.  */
  int die_perennial_p;
  unsigned int decl_id;
  enum dwarf_tag die_tag;
}
die_node;

/* Evaluate 'expr' while 'c' is set to each child of DIE in order.  */
#define FOR_EACH_CHILD(die, c, expr) do {       \
  c = die->die_child;                           \
  if (c) do {                                   \
    c = c->die_sib;                             \
    expr;                                       \
  } while (c != die->die_child);                \
} while (0)

/* The pubname structure */

typedef struct GTY(()) pubname_struct {
  dw_die_ref die;
  const char *name;
}
pubname_entry;

DEF_VEC_O(pubname_entry);
DEF_VEC_ALLOC_O(pubname_entry, gc);

struct GTY(()) dw_ranges_struct {
  /* If this is positive, it's a block number, otherwise it's a
     bitwise-negated index into dw_ranges_by_label.  */
  int num;
};

/* A structure to hold a macinfo entry.  */

typedef struct GTY(()) macinfo_struct {
  unsigned HOST_WIDE_INT code;
  unsigned HOST_WIDE_INT lineno;
  const char *info;
}
macinfo_entry;

DEF_VEC_O(macinfo_entry);
DEF_VEC_ALLOC_O(macinfo_entry, gc);

struct GTY(()) dw_ranges_by_label_struct {
  const char *begin;
  const char *end;
};

/* The comdat type node structure.  */
typedef struct GTY(()) comdat_type_struct
{
  dw_die_ref root_die;
  dw_die_ref type_die;
  char signature[DWARF_TYPE_SIGNATURE_SIZE];
  struct comdat_type_struct *next;
}
comdat_type_node;

/* The limbo die list structure.  */
typedef struct GTY(()) limbo_die_struct {
  dw_die_ref die;
  tree created_for;
  struct limbo_die_struct *next;
}
limbo_die_node;

typedef struct skeleton_chain_struct
{
  dw_die_ref old_die;
  dw_die_ref new_die;
  struct skeleton_chain_struct *parent;
}
skeleton_chain_node;

/* How to start an assembler comment.  */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif

/* Define a macro which returns nonzero for a TYPE_DECL which was
   implicitly generated for a tagged type.

   Note that unlike the gcc front end (which generates a NULL named
   TYPE_DECL node for each complete tagged type, each array type, and
   each function type node created) the g++ front end generates a
   _named_ TYPE_DECL node for each tagged type node created.
   These TYPE_DECLs have DECL_ARTIFICIAL set, so we know not to
   generate a DW_TAG_typedef DIE for them.  */

#define TYPE_DECL_IS_STUB(decl)                         \
  (DECL_NAME (decl) == NULL_TREE                        \
   || (DECL_ARTIFICIAL (decl)                           \
       && is_tagged_type (TREE_TYPE (decl))             \
       && ((decl == TYPE_STUB_DECL (TREE_TYPE (decl)))  \
           /* This is necessary for stub decls that     \
              appear in nested inline functions.  */    \
           || (DECL_ABSTRACT_ORIGIN (decl) != NULL_TREE \
               && (decl_ultimate_origin (decl)          \
                   == TYPE_STUB_DECL (TREE_TYPE (decl)))))))

/* Information concerning the compilation unit's programming
   language, and compiler version.  */

/* Fixed size portion of the DWARF compilation unit header.  */
#define DWARF_COMPILE_UNIT_HEADER_SIZE \
  (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 3)

/* Fixed size portion of the DWARF comdat type unit header.  */
#define DWARF_COMDAT_TYPE_UNIT_HEADER_SIZE \
  (DWARF_COMPILE_UNIT_HEADER_SIZE + DWARF_TYPE_SIGNATURE_SIZE \
   + DWARF_OFFSET_SIZE)

/* Fixed size portion of public names info.  */
#define DWARF_PUBNAMES_HEADER_SIZE (2 * DWARF_OFFSET_SIZE + 2)

/* Fixed size portion of the address range info.  */
#define DWARF_ARANGES_HEADER_SIZE                                       \
  (DWARF_ROUND (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 4,      \
                DWARF2_ADDR_SIZE * 2)                                   \
   - DWARF_INITIAL_LENGTH_SIZE)

/* Size of padding portion in the address range info.  It must be
   aligned to twice the pointer size.  */
#define DWARF_ARANGES_PAD_SIZE \
  (DWARF_ROUND (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 4, \
                DWARF2_ADDR_SIZE * 2)                              \
   - (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 4))

/* Use assembler line directives if available.  */
#ifndef DWARF2_ASM_LINE_DEBUG_INFO
#ifdef HAVE_AS_DWARF2_DEBUG_LINE
#define DWARF2_ASM_LINE_DEBUG_INFO 1
#else
#define DWARF2_ASM_LINE_DEBUG_INFO 0
#endif
#endif

/* Minimum line offset in a special line info. opcode.
   This value was chosen to give a reasonable range of values.  */
#define DWARF_LINE_BASE  -10

/* First special line opcode - leave room for the standard opcodes.  */
#define DWARF_LINE_OPCODE_BASE  10

/* Range of line offsets in a special line info. opcode.  */
#define DWARF_LINE_RANGE  (254-DWARF_LINE_OPCODE_BASE+1)

/* Flag that indicates the initial value of the is_stmt_start flag.
   In the present implementation, we do not mark any lines as
   the beginning of a source statement, because that information
   is not made available by the GCC front-end.  */
#define DWARF_LINE_DEFAULT_IS_STMT_START 1

/* Maximum number of operations per instruction bundle.  */
#ifndef DWARF_LINE_DEFAULT_MAX_OPS_PER_INSN
#define DWARF_LINE_DEFAULT_MAX_OPS_PER_INSN 1
#endif

/* This location is used by calc_die_sizes() to keep track
   the offset of each DIE within the .debug_info section.  */
static unsigned long next_die_offset;

/* Record the root of the DIE's built for the current compilation unit.  */
static GTY(()) dw_die_ref single_comp_unit_die;

/* A list of type DIEs that have been separated into comdat sections.  */
static GTY(()) comdat_type_node *comdat_type_list;

/* A list of DIEs with a NULL parent waiting to be relocated.  */
static GTY(()) limbo_die_node *limbo_die_list;

/* A list of DIEs for which we may have to generate
   DW_AT_{,MIPS_}linkage_name once their DECL_ASSEMBLER_NAMEs are set.  */
static GTY(()) limbo_die_node *deferred_asm_name;

/* Filenames referenced by this compilation unit.  */
static GTY((param_is (struct dwarf_file_data))) htab_t file_table;

/* A hash table of references to DIE's that describe declarations.
   The key is a DECL_UID() which is a unique number identifying each decl.  */
static GTY ((param_is (struct die_struct))) htab_t decl_die_table;

/* A hash table of references to DIE's that describe COMMON blocks.
   The key is DECL_UID() ^ die_parent.  */
static GTY ((param_is (struct die_struct))) htab_t common_block_die_table;

typedef struct GTY(()) die_arg_entry_struct {
    dw_die_ref die;
    tree arg;
} die_arg_entry;

DEF_VEC_O(die_arg_entry);
DEF_VEC_ALLOC_O(die_arg_entry,gc);

/* Node of the variable location list.  */
struct GTY ((chain_next ("%h.next"))) var_loc_node {
  /* Either NOTE_INSN_VAR_LOCATION, or, for SRA optimized variables,
     EXPR_LIST chain.  For small bitsizes, bitsize is encoded
     in mode of the EXPR_LIST node and first EXPR_LIST operand
     is either NOTE_INSN_VAR_LOCATION for a piece with a known
     location or NULL for padding.  For larger bitsizes,
     mode is 0 and first operand is a CONCAT with bitsize
     as first CONCAT operand and NOTE_INSN_VAR_LOCATION resp.
     NULL as second operand.  */
  rtx GTY (()) loc;
  const char * GTY (()) label;
  struct var_loc_node * GTY (()) next;
};

/* Variable location list.  */
struct GTY (()) var_loc_list_def {
  struct var_loc_node * GTY (()) first;

  /* Pointer to the last but one or last element of the
     chained list.  If the list is empty, both first and
     last are NULL, if the list contains just one node
     or the last node certainly is not redundant, it points
     to the last node, otherwise points to the last but one.
     Do not mark it for GC because it is marked through the chain.  */
  struct var_loc_node * GTY ((skip ("%h"))) last;

  /* DECL_UID of the variable decl.  */
  unsigned int decl_id;
};
typedef struct var_loc_list_def var_loc_list;


/* Table of decl location linked lists.  */
static GTY ((param_is (var_loc_list))) htab_t decl_loc_table;

/* A pointer to the base of a list of references to DIE's that
   are uniquely identified by their tag, presence/absence of
   children DIE's, and list of attribute/value pairs.  */
static GTY((length ("abbrev_die_table_allocated")))
  dw_die_ref *abbrev_die_table;

/* Number of elements currently allocated for abbrev_die_table.  */
static GTY(()) unsigned abbrev_die_table_allocated;

/* Number of elements in type_die_table currently in use.  */
static GTY(()) unsigned abbrev_die_table_in_use;

/* Size (in elements) of increments by which we may expand the
   abbrev_die_table.  */
#define ABBREV_DIE_TABLE_INCREMENT 256

/* A pointer to the base of a table that contains line information
   for each source code line in .text in the compilation unit.  */
static GTY((length ("line_info_table_allocated")))
     dw_line_info_ref line_info_table;

/* Number of elements currently allocated for line_info_table.  */
static GTY(()) unsigned line_info_table_allocated;

/* Number of elements in line_info_table currently in use.  */
static GTY(()) unsigned line_info_table_in_use;

/* A pointer to the base of a table that contains line information
   for each source code line outside of .text in the compilation unit.  */
static GTY ((length ("separate_line_info_table_allocated")))
     dw_separate_line_info_ref separate_line_info_table;

/* Number of elements currently allocated for separate_line_info_table.  */
static GTY(()) unsigned separate_line_info_table_allocated;

/* Number of elements in separate_line_info_table currently in use.  */
static GTY(()) unsigned separate_line_info_table_in_use;

/* Size (in elements) of increments by which we may expand the
   line_info_table.  */
#define LINE_INFO_TABLE_INCREMENT 1024

/* A flag to tell pubnames/types export if there is an info section to
   refer to.  */
static bool info_section_emitted;

/* A pointer to the base of a table that contains a list of publicly
   accessible names.  */
static GTY (()) VEC (pubname_entry, gc) *  pubname_table;

/* A pointer to the base of a table that contains a list of publicly
   accessible types.  */
static GTY (()) VEC (pubname_entry, gc) * pubtype_table;

/* A pointer to the base of a table that contains a list of macro
   defines/undefines (and file start/end markers).  */
static GTY (()) VEC (macinfo_entry, gc) * macinfo_table;

/* Array of dies for which we should generate .debug_arange info.  */
static GTY((length ("arange_table_allocated"))) dw_die_ref *arange_table;

/* Number of elements currently allocated for arange_table.  */
static GTY(()) unsigned arange_table_allocated;

/* Number of elements in arange_table currently in use.  */
static GTY(()) unsigned arange_table_in_use;

/* Size (in elements) of increments by which we may expand the
   arange_table.  */
#define ARANGE_TABLE_INCREMENT 64

/* Array of dies for which we should generate .debug_ranges info.  */
static GTY ((length ("ranges_table_allocated"))) dw_ranges_ref ranges_table;

/* Number of elements currently allocated for ranges_table.  */
static GTY(()) unsigned ranges_table_allocated;

/* Number of elements in ranges_table currently in use.  */
static GTY(()) unsigned ranges_table_in_use;

/* Array of pairs of labels referenced in ranges_table.  */
static GTY ((length ("ranges_by_label_allocated")))
     dw_ranges_by_label_ref ranges_by_label;

/* Number of elements currently allocated for ranges_by_label.  */
static GTY(()) unsigned ranges_by_label_allocated;

/* Number of elements in ranges_by_label currently in use.  */
static GTY(()) unsigned ranges_by_label_in_use;

/* Size (in elements) of increments by which we may expand the
   ranges_table.  */
#define RANGES_TABLE_INCREMENT 64

/* Whether we have location lists that need outputting */
static GTY(()) bool have_location_lists;

/* Unique label counter.  */
static GTY(()) unsigned int loclabel_num;

/* Unique label counter for point-of-call tables.  */
static GTY(()) unsigned int poc_label_num;

/* The direct call table structure.  */

typedef struct GTY(()) dcall_struct {
  unsigned int poc_label_num;
  tree poc_decl;
  dw_die_ref targ_die;
}
dcall_entry;

DEF_VEC_O(dcall_entry);
DEF_VEC_ALLOC_O(dcall_entry, gc);

/* The virtual call table structure.  */

typedef struct GTY(()) vcall_struct {
  unsigned int poc_label_num;
  unsigned int vtable_slot;
}
vcall_entry;

DEF_VEC_O(vcall_entry);
DEF_VEC_ALLOC_O(vcall_entry, gc);

/* Pointers to the direct and virtual call tables.  */
static GTY (()) VEC (dcall_entry, gc) * dcall_table = NULL;
static GTY (()) VEC (vcall_entry, gc) * vcall_table = NULL;

/* A hash table to map INSN_UIDs to vtable slot indexes.  */

struct GTY (()) vcall_insn {
  int insn_uid;
  unsigned int vtable_slot;
};

static GTY ((param_is (struct vcall_insn))) htab_t vcall_insn_table;

/* Record whether the function being analyzed contains inlined functions.  */
static int current_function_has_inlines;

/* The last file entry emitted by maybe_emit_file().  */
static GTY(()) struct dwarf_file_data * last_emitted_file;

/* Number of internal labels generated by gen_internal_sym().  */
static GTY(()) int label_num;

/* Cached result of previous call to lookup_filename.  */
static GTY(()) struct dwarf_file_data * file_table_last_lookup;

static GTY(()) VEC(die_arg_entry,gc) *tmpl_value_parm_die_table;

/* Offset from the "steady-state frame pointer" to the frame base,
   within the current function.  */
static HOST_WIDE_INT frame_pointer_fb_offset;

/* Forward declarations for functions defined in this file.  */

static int is_pseudo_reg (const_rtx);
static tree type_main_variant (tree);
static int is_tagged_type (const_tree);
static const char *dwarf_tag_name (unsigned);
static const char *dwarf_attr_name (unsigned);
static const char *dwarf_form_name (unsigned);
static tree decl_ultimate_origin (const_tree);
static tree decl_class_context (tree);
static void add_dwarf_attr (dw_die_ref, dw_attr_ref);
static inline enum dw_val_class AT_class (dw_attr_ref);
static void add_AT_flag (dw_die_ref, enum dwarf_attribute, unsigned);
static inline unsigned AT_flag (dw_attr_ref);
static void add_AT_int (dw_die_ref, enum dwarf_attribute, HOST_WIDE_INT);
static inline HOST_WIDE_INT AT_int (dw_attr_ref);
static void add_AT_unsigned (dw_die_ref, enum dwarf_attribute, unsigned HOST_WIDE_INT);
static inline unsigned HOST_WIDE_INT AT_unsigned (dw_attr_ref);
static void add_AT_double (dw_die_ref, enum dwarf_attribute,
                           HOST_WIDE_INT, unsigned HOST_WIDE_INT);
static inline void add_AT_vec (dw_die_ref, enum dwarf_attribute, unsigned int,
                               unsigned int, unsigned char *);
static void add_AT_data8 (dw_die_ref, enum dwarf_attribute, unsigned char *);
static hashval_t debug_str_do_hash (const void *);
static int debug_str_eq (const void *, const void *);
static void add_AT_string (dw_die_ref, enum dwarf_attribute, const char *);
static inline const char *AT_string (dw_attr_ref);
static enum dwarf_form AT_string_form (dw_attr_ref);
static void add_AT_die_ref (dw_die_ref, enum dwarf_attribute, dw_die_ref);
static void add_AT_specification (dw_die_ref, dw_die_ref);
static inline dw_die_ref AT_ref (dw_attr_ref);
static inline int AT_ref_external (dw_attr_ref);
static inline void set_AT_ref_external (dw_attr_ref, int);
static void add_AT_fde_ref (dw_die_ref, enum dwarf_attribute, unsigned);
static void add_AT_loc (dw_die_ref, enum dwarf_attribute, dw_loc_descr_ref);
static inline dw_loc_descr_ref AT_loc (dw_attr_ref);
static void add_AT_loc_list (dw_die_ref, enum dwarf_attribute,
                             dw_loc_list_ref);
static inline dw_loc_list_ref AT_loc_list (dw_attr_ref);
static void add_AT_addr (dw_die_ref, enum dwarf_attribute, rtx);
static inline rtx AT_addr (dw_attr_ref);
static void add_AT_lbl_id (dw_die_ref, enum dwarf_attribute, const char *);
static void add_AT_lineptr (dw_die_ref, enum dwarf_attribute, const char *);
static void add_AT_macptr (dw_die_ref, enum dwarf_attribute, const char *);
static void add_AT_offset (dw_die_ref, enum dwarf_attribute,
                           unsigned HOST_WIDE_INT);
static void add_AT_range_list (dw_die_ref, enum dwarf_attribute,
                               unsigned long);
static inline const char *AT_lbl (dw_attr_ref);
static dw_attr_ref get_AT (dw_die_ref, enum dwarf_attribute);
static const char *get_AT_low_pc (dw_die_ref);
static const char *get_AT_hi_pc (dw_die_ref);
static const char *get_AT_string (dw_die_ref, enum dwarf_attribute);
static int get_AT_flag (dw_die_ref, enum dwarf_attribute);
static unsigned get_AT_unsigned (dw_die_ref, enum dwarf_attribute);
static inline dw_die_ref get_AT_ref (dw_die_ref, enum dwarf_attribute);
static bool is_cxx (void);
static bool is_fortran (void);
static bool is_ada (void);
static void remove_AT (dw_die_ref, enum dwarf_attribute);
static void remove_child_TAG (dw_die_ref, enum dwarf_tag);
static void add_child_die (dw_die_ref, dw_die_ref);
static dw_die_ref new_die (enum dwarf_tag, dw_die_ref, tree);
static dw_die_ref lookup_type_die (tree);
static dw_die_ref lookup_type_die_strip_naming_typedef (tree);
static void equate_type_number_to_die (tree, dw_die_ref);
static hashval_t decl_die_table_hash (const void *);
static int decl_die_table_eq (const void *, const void *);
static dw_die_ref lookup_decl_die (tree);
static hashval_t common_block_die_table_hash (const void *);
static int common_block_die_table_eq (const void *, const void *);
static hashval_t decl_loc_table_hash (const void *);
static int decl_loc_table_eq (const void *, const void *);
static var_loc_list *lookup_decl_loc (const_tree);
static void equate_decl_number_to_die (tree, dw_die_ref);
static struct var_loc_node *add_var_loc_to_decl (tree, rtx, const char *);
static void print_spaces (FILE *);
static void print_die (dw_die_ref, FILE *);
static void print_dwarf_line_table (FILE *);
static dw_die_ref push_new_compile_unit (dw_die_ref, dw_die_ref);
static dw_die_ref pop_compile_unit (dw_die_ref);
static void loc_checksum (dw_loc_descr_ref, struct md5_ctx *);
static void attr_checksum (dw_attr_ref, struct md5_ctx *, int *);
static void die_checksum (dw_die_ref, struct md5_ctx *, int *);
static void checksum_sleb128 (HOST_WIDE_INT, struct md5_ctx *);
static void checksum_uleb128 (unsigned HOST_WIDE_INT, struct md5_ctx *);
static void loc_checksum_ordered (dw_loc_descr_ref, struct md5_ctx *);
static void attr_checksum_ordered (enum dwarf_tag, dw_attr_ref,
                                   struct md5_ctx *, int *);
struct checksum_attributes;
static void collect_checksum_attributes (struct checksum_attributes *, dw_die_ref);
static void die_checksum_ordered (dw_die_ref, struct md5_ctx *, int *);
static void checksum_die_context (dw_die_ref, struct md5_ctx *);
static void generate_type_signature (dw_die_ref, comdat_type_node *);
static int same_loc_p (dw_loc_descr_ref, dw_loc_descr_ref, int *);
static int same_dw_val_p (const dw_val_node *, const dw_val_node *, int *);
static int same_attr_p (dw_attr_ref, dw_attr_ref, int *);
static int same_die_p (dw_die_ref, dw_die_ref, int *);
static int same_die_p_wrap (dw_die_ref, dw_die_ref);
static void compute_section_prefix (dw_die_ref);
static int is_type_die (dw_die_ref);
static int is_comdat_die (dw_die_ref);
static int is_symbol_die (dw_die_ref);
static void assign_symbol_names (dw_die_ref);
static void break_out_includes (dw_die_ref);
static int is_declaration_die (dw_die_ref);
static int should_move_die_to_comdat (dw_die_ref);
static dw_die_ref clone_as_declaration (dw_die_ref);
static dw_die_ref clone_die (dw_die_ref);
static dw_die_ref clone_tree (dw_die_ref);
static void copy_declaration_context (dw_die_ref, dw_die_ref);
static void generate_skeleton_ancestor_tree (skeleton_chain_node *);
static void generate_skeleton_bottom_up (skeleton_chain_node *);
static dw_die_ref generate_skeleton (dw_die_ref);
static dw_die_ref remove_child_or_replace_with_skeleton (dw_die_ref,
                                                         dw_die_ref);
static void break_out_comdat_types (dw_die_ref);
static dw_die_ref copy_ancestor_tree (dw_die_ref, dw_die_ref, htab_t);
static void copy_decls_walk (dw_die_ref, dw_die_ref, htab_t);
static void copy_decls_for_unworthy_types (dw_die_ref);

static hashval_t htab_cu_hash (const void *);
static int htab_cu_eq (const void *, const void *);
static void htab_cu_del (void *);
static int check_duplicate_cu (dw_die_ref, htab_t, unsigned *);
static void record_comdat_symbol_number (dw_die_ref, htab_t, unsigned);
static void add_sibling_attributes (dw_die_ref);
static void build_abbrev_table (dw_die_ref);
static void output_location_lists (dw_die_ref);
static int constant_size (unsigned HOST_WIDE_INT);
static unsigned long size_of_die (dw_die_ref);
static void calc_die_sizes (dw_die_ref);
static void mark_dies (dw_die_ref);
static void unmark_dies (dw_die_ref);
static void unmark_all_dies (dw_die_ref);
static unsigned long size_of_pubnames (VEC (pubname_entry,gc) *);
static unsigned long size_of_aranges (void);
static enum dwarf_form value_format (dw_attr_ref);
static void output_value_format (dw_attr_ref);
static void output_abbrev_section (void);
static void output_die_symbol (dw_die_ref);
static void output_die (dw_die_ref);
static void output_compilation_unit_header (void);
static void output_comp_unit (dw_die_ref, int);
static void output_comdat_type_unit (comdat_type_node *);
static const char *dwarf2_name (tree, int);
static void add_pubname (tree, dw_die_ref);
static void add_pubname_string (const char *, dw_die_ref);
static void add_pubtype (tree, dw_die_ref);
static void output_pubnames (VEC (pubname_entry,gc) *);
static void add_arange (tree, dw_die_ref);
static void output_aranges (void);
static unsigned int add_ranges_num (int);
static unsigned int add_ranges (const_tree);
static void add_ranges_by_labels (dw_die_ref, const char *, const char *,
                                  bool *);
static void output_ranges (void);
static void output_line_info (void);
static void output_file_names (void);
static dw_die_ref base_type_die (tree);
static int is_base_type (tree);
static dw_die_ref subrange_type_die (tree, tree, tree, dw_die_ref);
static dw_die_ref modified_type_die (tree, int, int, dw_die_ref);
static dw_die_ref generic_parameter_die (tree, tree, bool, dw_die_ref);
static dw_die_ref template_parameter_pack_die (tree, tree, dw_die_ref);
static int type_is_enum (const_tree);
static unsigned int dbx_reg_number (const_rtx);
static void add_loc_descr_op_piece (dw_loc_descr_ref *, int);
static dw_loc_descr_ref reg_loc_descriptor (rtx, enum var_init_status);
static dw_loc_descr_ref one_reg_loc_descriptor (unsigned int,
                                                enum var_init_status);
static dw_loc_descr_ref multiple_reg_loc_descriptor (rtx, rtx,
                                                     enum var_init_status);
static dw_loc_descr_ref based_loc_descr (rtx, HOST_WIDE_INT,
                                         enum var_init_status);
static int is_based_loc (const_rtx);
static int resolve_one_addr (rtx *, void *);
static dw_loc_descr_ref concat_loc_descriptor (rtx, rtx,
                                               enum var_init_status);
static dw_loc_descr_ref loc_descriptor (rtx, enum machine_mode mode,
                                        enum var_init_status);
static dw_loc_list_ref loc_list_from_tree (tree, int);
static dw_loc_descr_ref loc_descriptor_from_tree (tree, int);
static HOST_WIDE_INT ceiling (HOST_WIDE_INT, unsigned int);
static tree field_type (const_tree);
static unsigned int simple_type_align_in_bits (const_tree);
static unsigned int simple_decl_align_in_bits (const_tree);
static unsigned HOST_WIDE_INT simple_type_size_in_bits (const_tree);
static HOST_WIDE_INT field_byte_offset (const_tree);
static void add_AT_location_description (dw_die_ref, enum dwarf_attribute,
                                         dw_loc_list_ref);
static void add_data_member_location_attribute (dw_die_ref, tree);
static bool add_const_value_attribute (dw_die_ref, rtx);
static void insert_int (HOST_WIDE_INT, unsigned, unsigned char *);
static void insert_double (double_int, unsigned char *);
static void insert_float (const_rtx, unsigned char *);
static rtx rtl_for_decl_location (tree);
static bool add_location_or_const_value_attribute (dw_die_ref, tree,
                                                   enum dwarf_attribute);
static bool tree_add_const_value_attribute (dw_die_ref, tree);
static bool tree_add_const_value_attribute_for_decl (dw_die_ref, tree);
static void add_name_attribute (dw_die_ref, const char *);
static void add_comp_dir_attribute (dw_die_ref);
static void add_bound_info (dw_die_ref, enum dwarf_attribute, tree);
static void add_subscript_info (dw_die_ref, tree, bool);
static void add_byte_size_attribute (dw_die_ref, tree);
static void add_bit_offset_attribute (dw_die_ref, tree);
static void add_bit_size_attribute (dw_die_ref, tree);
static void add_prototyped_attribute (dw_die_ref, tree);
static dw_die_ref add_abstract_origin_attribute (dw_die_ref, tree);
static void add_pure_or_virtual_attribute (dw_die_ref, tree);
static void add_src_coords_attributes (dw_die_ref, tree);
static void add_name_and_src_coords_attributes (dw_die_ref, tree);
static void push_decl_scope (tree);
static void pop_decl_scope (void);
static dw_die_ref scope_die_for (tree, dw_die_ref);
static inline int local_scope_p (dw_die_ref);
static inline int class_scope_p (dw_die_ref);
static inline int class_or_namespace_scope_p (dw_die_ref);
static void add_type_attribute (dw_die_ref, tree, int, int, dw_die_ref);
static void add_calling_convention_attribute (dw_die_ref, tree);
static const char *type_tag (const_tree);
static tree member_declared_type (const_tree);
#if 0
static const char *decl_start_label (tree);
#endif
static void gen_array_type_die (tree, dw_die_ref);
static void gen_descr_array_type_die (tree, struct array_descr_info *, dw_die_ref);
#if 0
static void gen_entry_point_die (tree, dw_die_ref);
#endif
static dw_die_ref gen_enumeration_type_die (tree, dw_die_ref);
static dw_die_ref gen_formal_parameter_die (tree, tree, bool, dw_die_ref);
static dw_die_ref gen_formal_parameter_pack_die  (tree, tree, dw_die_ref, tree*);
static void gen_unspecified_parameters_die (tree, dw_die_ref);
static void gen_formal_types_die (tree, dw_die_ref);
static void gen_subprogram_die (tree, dw_die_ref);
static void gen_variable_die (tree, tree, dw_die_ref);
static void gen_const_die (tree, dw_die_ref);
static void gen_label_die (tree, dw_die_ref);
static void gen_lexical_block_die (tree, dw_die_ref, int);
static void gen_inlined_subroutine_die (tree, dw_die_ref, int);
static void gen_field_die (tree, dw_die_ref);
static void gen_ptr_to_mbr_type_die (tree, dw_die_ref);
static dw_die_ref gen_compile_unit_die (const char *);
static void gen_inheritance_die (tree, tree, dw_die_ref);
static void gen_member_die (tree, dw_die_ref);
static void gen_struct_or_union_type_die (tree, dw_die_ref,
                                                enum debug_info_usage);
static void gen_subroutine_type_die (tree, dw_die_ref);
static void gen_typedef_die (tree, dw_die_ref);
static void gen_type_die (tree, dw_die_ref);
static void gen_block_die (tree, dw_die_ref, int);
static void decls_for_scope (tree, dw_die_ref, int);
static int is_redundant_typedef (const_tree);
static bool is_naming_typedef_decl (const_tree);
static inline dw_die_ref get_context_die (tree);
static void gen_namespace_die (tree, dw_die_ref);
static dw_die_ref gen_decl_die (tree, tree, dw_die_ref);
static dw_die_ref force_decl_die (tree);
static dw_die_ref force_type_die (tree);
static dw_die_ref setup_namespace_context (tree, dw_die_ref);
static dw_die_ref declare_in_namespace (tree, dw_die_ref);
static struct dwarf_file_data * lookup_filename (const char *);
static void retry_incomplete_types (void);
static void gen_type_die_for_member (tree, tree, dw_die_ref);
static void gen_generic_params_dies (tree);
static void gen_tagged_type_die (tree, dw_die_ref, enum debug_info_usage);
static void gen_type_die_with_usage (tree, dw_die_ref, enum debug_info_usage);
static void splice_child_die (dw_die_ref, dw_die_ref);
static int file_info_cmp (const void *, const void *);
static dw_loc_list_ref new_loc_list (dw_loc_descr_ref, const char *,
                                     const char *, const char *);
static void output_loc_list (dw_loc_list_ref);
static char *gen_internal_sym (const char *);

static void prune_unmark_dies (dw_die_ref);
static void prune_unused_types_mark (dw_die_ref, int);
static void prune_unused_types_walk (dw_die_ref);
static void prune_unused_types_walk_attribs (dw_die_ref);
static void prune_unused_types_prune (dw_die_ref);
static void prune_unused_types (void);
static int maybe_emit_file (struct dwarf_file_data *fd);
static inline const char *AT_vms_delta1 (dw_attr_ref);
static inline const char *AT_vms_delta2 (dw_attr_ref);
static inline void add_AT_vms_delta (dw_die_ref, enum dwarf_attribute,
                                     const char *, const char *);
static void append_entry_to_tmpl_value_parm_die_table (dw_die_ref, tree);
static void gen_remaining_tmpl_value_param_die_attribute (void);

/* Section names used to hold DWARF debugging information.  */
#ifndef DEBUG_INFO_SECTION
#define DEBUG_INFO_SECTION      ".debug_info"
#endif
#ifndef DEBUG_ABBREV_SECTION
#define DEBUG_ABBREV_SECTION    ".debug_abbrev"
#endif
#ifndef DEBUG_ARANGES_SECTION
#define DEBUG_ARANGES_SECTION   ".debug_aranges"
#endif
#ifndef DEBUG_MACINFO_SECTION
#define DEBUG_MACINFO_SECTION   ".debug_macinfo"
#endif
#ifndef DEBUG_LINE_SECTION
#define DEBUG_LINE_SECTION      ".debug_line"
#endif
#ifndef DEBUG_LOC_SECTION
#define DEBUG_LOC_SECTION       ".debug_loc"
#endif
#ifndef DEBUG_PUBNAMES_SECTION
#define DEBUG_PUBNAMES_SECTION  ".debug_pubnames"
#endif
#ifndef DEBUG_PUBTYPES_SECTION
#define DEBUG_PUBTYPES_SECTION  ".debug_pubtypes"
#endif
#ifndef DEBUG_DCALL_SECTION
#define DEBUG_DCALL_SECTION     ".debug_dcall"
#endif
#ifndef DEBUG_VCALL_SECTION
#define DEBUG_VCALL_SECTION     ".debug_vcall"
#endif
#ifndef DEBUG_STR_SECTION
#define DEBUG_STR_SECTION       ".debug_str"
#endif
#ifndef DEBUG_RANGES_SECTION
#define DEBUG_RANGES_SECTION    ".debug_ranges"
#endif

/* Standard ELF section names for compiled code and data.  */
#ifndef TEXT_SECTION_NAME
#define TEXT_SECTION_NAME       ".text"
#endif

/* Section flags for .debug_str section.  */
#define DEBUG_STR_SECTION_FLAGS \
  (HAVE_GAS_SHF_MERGE && flag_merge_debug_strings               \
   ? SECTION_DEBUG | SECTION_MERGE | SECTION_STRINGS | 1        \
   : SECTION_DEBUG)

/* Labels we insert at beginning sections we can reference instead of
   the section names themselves.  */

#ifndef TEXT_SECTION_LABEL
#define TEXT_SECTION_LABEL              "Ltext"
#endif
#ifndef COLD_TEXT_SECTION_LABEL
#define COLD_TEXT_SECTION_LABEL         "Ltext_cold"
#endif
#ifndef DEBUG_LINE_SECTION_LABEL
#define DEBUG_LINE_SECTION_LABEL        "Ldebug_line"
#endif
#ifndef DEBUG_INFO_SECTION_LABEL
#define DEBUG_INFO_SECTION_LABEL        "Ldebug_info"
#endif
#ifndef DEBUG_ABBREV_SECTION_LABEL
#define DEBUG_ABBREV_SECTION_LABEL      "Ldebug_abbrev"
#endif
#ifndef DEBUG_LOC_SECTION_LABEL
#define DEBUG_LOC_SECTION_LABEL         "Ldebug_loc"
#endif
#ifndef DEBUG_RANGES_SECTION_LABEL
#define DEBUG_RANGES_SECTION_LABEL      "Ldebug_ranges"
#endif
#ifndef DEBUG_MACINFO_SECTION_LABEL
#define DEBUG_MACINFO_SECTION_LABEL     "Ldebug_macinfo"
#endif


/* Definitions of defaults for formats and names of various special
   (artificial) labels which may be generated within this file (when the -g
   options is used and DWARF2_DEBUGGING_INFO is in effect.
   If necessary, these may be overridden from within the tm.h file, but
   typically, overriding these defaults is unnecessary.  */

static char text_end_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char text_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char cold_text_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char cold_end_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char abbrev_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char debug_info_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char debug_line_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char macinfo_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char loc_section_label[MAX_ARTIFICIAL_LABEL_BYTES];
static char ranges_section_label[2 * MAX_ARTIFICIAL_LABEL_BYTES];

#ifndef TEXT_END_LABEL
#define TEXT_END_LABEL          "Letext"
#endif
#ifndef COLD_END_LABEL
#define COLD_END_LABEL          "Letext_cold"
#endif
#ifndef BLOCK_BEGIN_LABEL
#define BLOCK_BEGIN_LABEL       "LBB"
#endif
#ifndef BLOCK_END_LABEL
#define BLOCK_END_LABEL         "LBE"
#endif
#ifndef LINE_CODE_LABEL
#define LINE_CODE_LABEL         "LM"
#endif
#ifndef SEPARATE_LINE_CODE_LABEL
#define SEPARATE_LINE_CODE_LABEL        "LSM"
#endif

\f
/* Return the root of the DIE's built for the current compilation unit.  */
static dw_die_ref
comp_unit_die (void)
{
  if (!single_comp_unit_die)
    single_comp_unit_die = gen_compile_unit_die (NULL);
  return single_comp_unit_die;
}

/* We allow a language front-end to designate a function that is to be
   called to "demangle" any name before it is put into a DIE.  */

static const char *(*demangle_name_func) (const char *);

void
dwarf2out_set_demangle_name_func (const char *(*func) (const char *))
{
  demangle_name_func = func;
}

/* Test if rtl node points to a pseudo register.  */

static inline int
is_pseudo_reg (const_rtx rtl)
{
  return ((REG_P (rtl) && REGNO (rtl) >= FIRST_PSEUDO_REGISTER)
          || (GET_CODE (rtl) == SUBREG
              && REGNO (SUBREG_REG (rtl)) >= FIRST_PSEUDO_REGISTER));
}

/* Return a reference to a type, with its const and volatile qualifiers
   removed.  */

static inline tree
type_main_variant (tree type)
{
  type = TYPE_MAIN_VARIANT (type);

  /* ??? There really should be only one main variant among any group of
     variants of a given type (and all of the MAIN_VARIANT values for all
     members of the group should point to that one type) but sometimes the C
     front-end messes this up for array types, so we work around that bug
     here.  */
  if (TREE_CODE (type) == ARRAY_TYPE)
    while (type != TYPE_MAIN_VARIANT (type))
      type = TYPE_MAIN_VARIANT (type);

  return type;
}

/* Return nonzero if the given type node represents a tagged type.  */

static inline int
is_tagged_type (const_tree type)
{
  enum tree_code code = TREE_CODE (type);

  return (code == RECORD_TYPE || code == UNION_TYPE
          || code == QUAL_UNION_TYPE || code == ENUMERAL_TYPE);
}

/* Set label to debug_info_section_label + die_offset of a DIE reference.  */

static void
get_ref_die_offset_label (char *label, dw_die_ref ref)
{
  sprintf (label, "%s+%ld", debug_info_section_label, ref->die_offset);
}

/* Convert a DIE tag into its string name.  */

static const char *
dwarf_tag_name (unsigned int tag)
{
  switch (tag)
    {
    case DW_TAG_padding:
      return "DW_TAG_padding";
    case DW_TAG_array_type:
      return "DW_TAG_array_type";
    case DW_TAG_class_type:
      return "DW_TAG_class_type";
    case DW_TAG_entry_point:
      return "DW_TAG_entry_point";
    case DW_TAG_enumeration_type:
      return "DW_TAG_enumeration_type";
    case DW_TAG_formal_parameter:
      return "DW_TAG_formal_parameter";
    case DW_TAG_imported_declaration:
      return "DW_TAG_imported_declaration";
    case DW_TAG_label:
      return "DW_TAG_label";
    case DW_TAG_lexical_block:
      return "DW_TAG_lexical_block";
    case DW_TAG_member:
      return "DW_TAG_member";
    case DW_TAG_pointer_type:
      return "DW_TAG_pointer_type";
    case DW_TAG_reference_type:
      return "DW_TAG_reference_type";
    case DW_TAG_compile_unit:
      return "DW_TAG_compile_unit";
    case DW_TAG_string_type:
      return "DW_TAG_string_type";
    case DW_TAG_structure_type:
      return "DW_TAG_structure_type";
    case DW_TAG_subroutine_type:
      return "DW_TAG_subroutine_type";
    case DW_TAG_typedef:
      return "DW_TAG_typedef";
    case DW_TAG_union_type:
      return "DW_TAG_union_type";
    case DW_TAG_unspecified_parameters:
      return "DW_TAG_unspecified_parameters";
    case DW_TAG_variant:
      return "DW_TAG_variant";
    case DW_TAG_common_block:
      return "DW_TAG_common_block";
    case DW_TAG_common_inclusion:
      return "DW_TAG_common_inclusion";
    case DW_TAG_inheritance:
      return "DW_TAG_inheritance";
    case DW_TAG_inlined_subroutine:
      return "DW_TAG_inlined_subroutine";
    case DW_TAG_module:
      return "DW_TAG_module";
    case DW_TAG_ptr_to_member_type:
      return "DW_TAG_ptr_to_member_type";
    case DW_TAG_set_type:
      return "DW_TAG_set_type";
    case DW_TAG_subrange_type:
      return "DW_TAG_subrange_type";
    case DW_TAG_with_stmt:
      return "DW_TAG_with_stmt";
    case DW_TAG_access_declaration:
      return "DW_TAG_access_declaration";
    case DW_TAG_base_type:
      return "DW_TAG_base_type";
    case DW_TAG_catch_block:
      return "DW_TAG_catch_block";
    case DW_TAG_const_type:
      return "DW_TAG_const_type";
    case DW_TAG_constant:
      return "DW_TAG_constant";
    case DW_TAG_enumerator:
      return "DW_TAG_enumerator";
    case DW_TAG_file_type:
      return "DW_TAG_file_type";
    case DW_TAG_friend:
      return "DW_TAG_friend";
    case DW_TAG_namelist:
      return "DW_TAG_namelist";
    case DW_TAG_namelist_item:
      return "DW_TAG_namelist_item";
    case DW_TAG_packed_type:
      return "DW_TAG_packed_type";
    case DW_TAG_subprogram:
      return "DW_TAG_subprogram";
    case DW_TAG_template_type_param:
      return "DW_TAG_template_type_param";
    case DW_TAG_template_value_param:
      return "DW_TAG_template_value_param";
    case DW_TAG_thrown_type:
      return "DW_TAG_thrown_type";
    case DW_TAG_try_block:
      return "DW_TAG_try_block";
    case DW_TAG_variant_part:
      return "DW_TAG_variant_part";
    case DW_TAG_variable:
      return "DW_TAG_variable";
    case DW_TAG_volatile_type:
      return "DW_TAG_volatile_type";
    case DW_TAG_dwarf_procedure:
      return "DW_TAG_dwarf_procedure";
    case DW_TAG_restrict_type:
      return "DW_TAG_restrict_type";
    case DW_TAG_interface_type:
      return "DW_TAG_interface_type";
    case DW_TAG_namespace:
      return "DW_TAG_namespace";
    case DW_TAG_imported_module:
      return "DW_TAG_imported_module";
    case DW_TAG_unspecified_type:
      return "DW_TAG_unspecified_type";
    case DW_TAG_partial_unit:
      return "DW_TAG_partial_unit";
    case DW_TAG_imported_unit:
      return "DW_TAG_imported_unit";
    case DW_TAG_condition:
      return "DW_TAG_condition";
    case DW_TAG_shared_type:
      return "DW_TAG_shared_type";
    case DW_TAG_type_unit:
      return "DW_TAG_type_unit";
    case DW_TAG_rvalue_reference_type:
      return "DW_TAG_rvalue_reference_type";
    case DW_TAG_template_alias:
      return "DW_TAG_template_alias";
    case DW_TAG_GNU_template_parameter_pack:
      return "DW_TAG_GNU_template_parameter_pack";
    case DW_TAG_GNU_formal_parameter_pack:
      return "DW_TAG_GNU_formal_parameter_pack";
    case DW_TAG_MIPS_loop:
      return "DW_TAG_MIPS_loop";
    case DW_TAG_format_label:
      return "DW_TAG_format_label";
    case DW_TAG_function_template:
      return "DW_TAG_function_template";
    case DW_TAG_class_template:
      return "DW_TAG_class_template";
    case DW_TAG_GNU_BINCL:
      return "DW_TAG_GNU_BINCL";
    case DW_TAG_GNU_EINCL:
      return "DW_TAG_GNU_EINCL";
    case DW_TAG_GNU_template_template_param:
      return "DW_TAG_GNU_template_template_param";
    default:
      return "DW_TAG_<unknown>";
    }
}

/* Convert a DWARF attribute code into its string name.  */

static const char *
dwarf_attr_name (unsigned int attr)
{
  switch (attr)
    {
    case DW_AT_sibling:
      return "DW_AT_sibling";
    case DW_AT_location:
      return "DW_AT_location";
    case DW_AT_name:
      return "DW_AT_name";
    case DW_AT_ordering:
      return "DW_AT_ordering";
    case DW_AT_subscr_data:
      return "DW_AT_subscr_data";
    case DW_AT_byte_size:
      return "DW_AT_byte_size";
    case DW_AT_bit_offset:
      return "DW_AT_bit_offset";
    case DW_AT_bit_size:
      return "DW_AT_bit_size";
    case DW_AT_element_list:
      return "DW_AT_element_list";
    case DW_AT_stmt_list:
      return "DW_AT_stmt_list";
    case DW_AT_low_pc:
      return "DW_AT_low_pc";
    case DW_AT_high_pc:
      return "DW_AT_high_pc";
    case DW_AT_language:
      return "DW_AT_language";
    case DW_AT_member:
      return "DW_AT_member";
    case DW_AT_discr:
      return "DW_AT_discr";
    case DW_AT_discr_value:
      return "DW_AT_discr_value";
    case DW_AT_visibility:
      return "DW_AT_visibility";
    case DW_AT_import:
      return "DW_AT_import";
    case DW_AT_string_length:
      return "DW_AT_string_length";
    case DW_AT_common_reference:
      return "DW_AT_common_reference";
    case DW_AT_comp_dir:
      return "DW_AT_comp_dir";
    case DW_AT_const_value:
      return "DW_AT_const_value";
    case DW_AT_containing_type:
      return "DW_AT_containing_type";
    case DW_AT_default_value:
      return "DW_AT_default_value";
    case DW_AT_inline:
      return "DW_AT_inline";
    case DW_AT_is_optional:
      return "DW_AT_is_optional";
    case DW_AT_lower_bound:
      return "DW_AT_lower_bound";
    case DW_AT_producer:
      return "DW_AT_producer";
    case DW_AT_prototyped:
      return "DW_AT_prototyped";
    case DW_AT_return_addr:
      return "DW_AT_return_addr";
    case DW_AT_start_scope:
      return "DW_AT_start_scope";
    case DW_AT_bit_stride:
      return "DW_AT_bit_stride";
    case DW_AT_upper_bound:
      return "DW_AT_upper_bound";
    case DW_AT_abstract_origin:
      return "DW_AT_abstract_origin";
    case DW_AT_accessibility:
      return "DW_AT_accessibility";
    case DW_AT_address_class:
      return "DW_AT_address_class";
    case DW_AT_artificial:
      return "DW_AT_artificial";
    case DW_AT_base_types:
      return "DW_AT_base_types";
    case DW_AT_calling_convention:
      return "DW_AT_calling_convention";
    case DW_AT_count:
      return "DW_AT_count";
    case DW_AT_data_member_location:
      return "DW_AT_data_member_location";
    case DW_AT_decl_column:
      return "DW_AT_decl_column";
    case DW_AT_decl_file:
      return "DW_AT_decl_file";
    case DW_AT_decl_line:
      return "DW_AT_decl_line";
    case DW_AT_declaration:
      return "DW_AT_declaration";
    case DW_AT_discr_list:
      return "DW_AT_discr_list";
    case DW_AT_encoding:
      return "DW_AT_encoding";
    case DW_AT_external:
      return "DW_AT_external";
    case DW_AT_explicit:
      return "DW_AT_explicit";
    case DW_AT_frame_base:
      return "DW_AT_frame_base";
    case DW_AT_friend:
      return "DW_AT_friend";
    case DW_AT_identifier_case:
      return "DW_AT_identifier_case";
    case DW_AT_macro_info:
      return "DW_AT_macro_info";
    case DW_AT_namelist_items:
      return "DW_AT_namelist_items";
    case DW_AT_priority:
      return "DW_AT_priority";
    case DW_AT_segment:
      return "DW_AT_segment";
    case DW_AT_specification:
      return "DW_AT_specification";
    case DW_AT_static_link:
      return "DW_AT_static_link";
    case DW_AT_type:
      return "DW_AT_type";
    case DW_AT_use_location:
      return "DW_AT_use_location";
    case DW_AT_variable_parameter:
      return "DW_AT_variable_parameter";
    case DW_AT_virtuality:
      return "DW_AT_virtuality";
    case DW_AT_vtable_elem_location:
      return "DW_AT_vtable_elem_location";

    case DW_AT_allocated:
      return "DW_AT_allocated";
    case DW_AT_associated:
      return "DW_AT_associated";
    case DW_AT_data_location:
      return "DW_AT_data_location";
    case DW_AT_byte_stride:
      return "DW_AT_byte_stride";
    case DW_AT_entry_pc:
      return "DW_AT_entry_pc";
    case DW_AT_use_UTF8:
      return "DW_AT_use_UTF8";
    case DW_AT_extension:
      return "DW_AT_extension";
    case DW_AT_ranges:
      return "DW_AT_ranges";
    case DW_AT_trampoline:
      return "DW_AT_trampoline";
    case DW_AT_call_column:
      return "DW_AT_call_column";
    case DW_AT_call_file:
      return "DW_AT_call_file";
    case DW_AT_call_line:
      return "DW_AT_call_line";
    case DW_AT_object_pointer:
      return "DW_AT_object_pointer";

    case DW_AT_signature:
      return "DW_AT_signature";
    case DW_AT_main_subprogram:
      return "DW_AT_main_subprogram";
    case DW_AT_data_bit_offset:
      return "DW_AT_data_bit_offset";
    case DW_AT_const_expr:
      return "DW_AT_const_expr";
    case DW_AT_enum_class:
      return "DW_AT_enum_class";
    case DW_AT_linkage_name:
      return "DW_AT_linkage_name";

    case DW_AT_MIPS_fde:
      return "DW_AT_MIPS_fde";
    case DW_AT_MIPS_loop_begin:
      return "DW_AT_MIPS_loop_begin";
    case DW_AT_MIPS_tail_loop_begin:
      return "DW_AT_MIPS_tail_loop_begin";
    case DW_AT_MIPS_epilog_begin:
      return "DW_AT_MIPS_epilog_begin";
#if VMS_DEBUGGING_INFO
    case DW_AT_HP_prologue:
      return "DW_AT_HP_prologue";
#else
    case DW_AT_MIPS_loop_unroll_factor:
      return "DW_AT_MIPS_loop_unroll_factor";
#endif
    case DW_AT_MIPS_software_pipeline_depth:
      return "DW_AT_MIPS_software_pipeline_depth";
    case DW_AT_MIPS_linkage_name:
      return "DW_AT_MIPS_linkage_name";
#if VMS_DEBUGGING_INFO
    case DW_AT_HP_epilogue:
      return "DW_AT_HP_epilogue";
#else
    case DW_AT_MIPS_stride:
      return "DW_AT_MIPS_stride";
#endif
    case DW_AT_MIPS_abstract_name:
      return "DW_AT_MIPS_abstract_name";
    case DW_AT_MIPS_clone_origin:
      return "DW_AT_MIPS_clone_origin";
    case DW_AT_MIPS_has_inlines:
      return "DW_AT_MIPS_has_inlines";

    case DW_AT_sf_names:
      return "DW_AT_sf_names";
    case DW_AT_src_info:
      return "DW_AT_src_info";
    case DW_AT_mac_info:
      return "DW_AT_mac_info";
    case DW_AT_src_coords:
      return "DW_AT_src_coords";
    case DW_AT_body_begin:
      return "DW_AT_body_begin";
    case DW_AT_body_end:
      return "DW_AT_body_end";
    case DW_AT_GNU_vector:
      return "DW_AT_GNU_vector";
    case DW_AT_GNU_guarded_by:
      return "DW_AT_GNU_guarded_by";
    case DW_AT_GNU_pt_guarded_by:
      return "DW_AT_GNU_pt_guarded_by";
    case DW_AT_GNU_guarded:
      return "DW_AT_GNU_guarded";
    case DW_AT_GNU_pt_guarded:
      return "DW_AT_GNU_pt_guarded";
    case DW_AT_GNU_locks_excluded:
      return "DW_AT_GNU_locks_excluded";
    case DW_AT_GNU_exclusive_locks_required:
      return "DW_AT_GNU_exclusive_locks_required";
    case DW_AT_GNU_shared_locks_required:
      return "DW_AT_GNU_shared_locks_required";
    case DW_AT_GNU_odr_signature:
      return "DW_AT_GNU_odr_signature";
    case DW_AT_GNU_template_name:
      return "DW_AT_GNU_template_name";

    case DW_AT_VMS_rtnbeg_pd_address:
      return "DW_AT_VMS_rtnbeg_pd_address";

    default:
      return "DW_AT_<unknown>";
    }
}

/* Convert a DWARF value form code into its string name.  */

static const char *
dwarf_form_name (unsigned int form)
{
  switch (form)
    {
    case DW_FORM_addr:
      return "DW_FORM_addr";
    case DW_FORM_block2:
      return "DW_FORM_block2";
    case DW_FORM_block4:
      return "DW_FORM_block4";
    case DW_FORM_data2:
      return "DW_FORM_data2";
    case DW_FORM_data4:
      return "DW_FORM_data4";
    case DW_FORM_data8:
      return "DW_FORM_data8";
    case DW_FORM_string:
      return "DW_FORM_string";
    case DW_FORM_block:
      return "DW_FORM_block";
    case DW_FORM_block1:
      return "DW_FORM_block1";
    case DW_FORM_data1:
      return "DW_FORM_data1";
    case DW_FORM_flag:
      return "DW_FORM_flag";
    case DW_FORM_sdata:
      return "DW_FORM_sdata";
    case DW_FORM_strp:
      return "DW_FORM_strp";
    case DW_FORM_udata:
      return "DW_FORM_udata";
    case DW_FORM_ref_addr:
      return "DW_FORM_ref_addr";
    case DW_FORM_ref1:
      return "DW_FORM_ref1";
    case DW_FORM_ref2:
      return "DW_FORM_ref2";
    case DW_FORM_ref4:
      return "DW_FORM_ref4";
    case DW_FORM_ref8:
      return "DW_FORM_ref8";
    case DW_FORM_ref_udata:
      return "DW_FORM_ref_udata";
    case DW_FORM_indirect:
      return "DW_FORM_indirect";
    case DW_FORM_sec_offset:
      return "DW_FORM_sec_offset";
    case DW_FORM_exprloc:
      return "DW_FORM_exprloc";
    case DW_FORM_flag_present:
      return "DW_FORM_flag_present";
    case DW_FORM_ref_sig8:
      return "DW_FORM_ref_sig8";
    default:
      return "DW_FORM_<unknown>";
    }
}
\f
/* Determine the "ultimate origin" of a decl.  The decl may be an inlined
   instance of an inlined instance of a decl which is local to an inline
   function, so we have to trace all of the way back through the origin chain
   to find out what sort of node actually served as the original seed for the
   given block.  */

static tree
decl_ultimate_origin (const_tree decl)
{
  if (!CODE_CONTAINS_STRUCT (TREE_CODE (decl), TS_DECL_COMMON))
    return NULL_TREE;

  /* output_inline_function sets DECL_ABSTRACT_ORIGIN for all the
     nodes in the function to point to themselves; ignore that if
     we're trying to output the abstract instance of this function.  */
  if (DECL_ABSTRACT (decl) && DECL_ABSTRACT_ORIGIN (decl) == decl)
    return NULL_TREE;

  /* Since the DECL_ABSTRACT_ORIGIN for a DECL is supposed to be the
     most distant ancestor, this should never happen.  */
  gcc_assert (!DECL_FROM_INLINE (DECL_ORIGIN (decl)));

  return DECL_ABSTRACT_ORIGIN (decl);
}

/* Get the class to which DECL belongs, if any.  In g++, the DECL_CONTEXT
   of a virtual function may refer to a base class, so we check the 'this'
   parameter.  */

static tree
decl_class_context (tree decl)
{
  tree context = NULL_TREE;

  if (TREE_CODE (decl) != FUNCTION_DECL || ! DECL_VINDEX (decl))
    context = DECL_CONTEXT (decl);
  else
    context = TYPE_MAIN_VARIANT
      (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (decl)))));

  if (context && !TYPE_P (context))
    context = NULL_TREE;

  return context;
}
\f
/* Add an attribute/value pair to a DIE.  */

static inline void
add_dwarf_attr (dw_die_ref die, dw_attr_ref attr)
{
  /* Maybe this should be an assert?  */
  if (die == NULL)
    return;

  if (die->die_attr == NULL)
    die->die_attr = VEC_alloc (dw_attr_node, gc, 1);
  VEC_safe_push (dw_attr_node, gc, die->die_attr, attr);
}

static inline enum dw_val_class
AT_class (dw_attr_ref a)
{
  return a->dw_attr_val.val_class;
}

/* Add a flag value attribute to a DIE.  */

static inline void
add_AT_flag (dw_die_ref die, enum dwarf_attribute attr_kind, unsigned int flag)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_flag;
  attr.dw_attr_val.v.val_flag = flag;
  add_dwarf_attr (die, &attr);
}

static inline unsigned
AT_flag (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_flag);
  return a->dw_attr_val.v.val_flag;
}

/* Add a signed integer attribute value to a DIE.  */

static inline void
add_AT_int (dw_die_ref die, enum dwarf_attribute attr_kind, HOST_WIDE_INT int_val)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_const;
  attr.dw_attr_val.v.val_int = int_val;
  add_dwarf_attr (die, &attr);
}

static inline HOST_WIDE_INT
AT_int (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_const);
  return a->dw_attr_val.v.val_int;
}

/* Add an unsigned integer attribute value to a DIE.  */

static inline void
add_AT_unsigned (dw_die_ref die, enum dwarf_attribute attr_kind,
                 unsigned HOST_WIDE_INT unsigned_val)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_unsigned_const;
  attr.dw_attr_val.v.val_unsigned = unsigned_val;
  add_dwarf_attr (die, &attr);
}

static inline unsigned HOST_WIDE_INT
AT_unsigned (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_unsigned_const);
  return a->dw_attr_val.v.val_unsigned;
}

/* Add an unsigned double integer attribute value to a DIE.  */

static inline void
add_AT_double (dw_die_ref die, enum dwarf_attribute attr_kind,
               HOST_WIDE_INT high, unsigned HOST_WIDE_INT low)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_const_double;
  attr.dw_attr_val.v.val_double.high = high;
  attr.dw_attr_val.v.val_double.low = low;
  add_dwarf_attr (die, &attr);
}

/* Add a floating point attribute value to a DIE and return it.  */

static inline void
add_AT_vec (dw_die_ref die, enum dwarf_attribute attr_kind,
            unsigned int length, unsigned int elt_size, unsigned char *array)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_vec;
  attr.dw_attr_val.v.val_vec.length = length;
  attr.dw_attr_val.v.val_vec.elt_size = elt_size;
  attr.dw_attr_val.v.val_vec.array = array;
  add_dwarf_attr (die, &attr);
}

/* Add an 8-byte data attribute value to a DIE.  */

static inline void
add_AT_data8 (dw_die_ref die, enum dwarf_attribute attr_kind,
              unsigned char data8[8])
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_data8;
  memcpy (attr.dw_attr_val.v.val_data8, data8, 8);
  add_dwarf_attr (die, &attr);
}

/* Hash and equality functions for debug_str_hash.  */

static hashval_t
debug_str_do_hash (const void *x)
{
  return htab_hash_string (((const struct indirect_string_node *)x)->str);
}

static int
debug_str_eq (const void *x1, const void *x2)
{
  return strcmp ((((const struct indirect_string_node *)x1)->str),
                 (const char *)x2) == 0;
}

/* Add STR to the indirect string hash table.  */

static struct indirect_string_node *
find_AT_string (const char *str)
{
  struct indirect_string_node *node;
  void **slot;

  if (! debug_str_hash)
    debug_str_hash = htab_create_ggc (10, debug_str_do_hash,
                                      debug_str_eq, NULL);

  slot = htab_find_slot_with_hash (debug_str_hash, str,
                                   htab_hash_string (str), INSERT);
  if (*slot == NULL)
    {
      node = ggc_alloc_cleared_indirect_string_node ();
      node->str = ggc_strdup (str);
      *slot = node;
    }
  else
    node = (struct indirect_string_node *) *slot;

  node->refcount++;
  return node;
}

/* Add a string attribute value to a DIE.  */

static inline void
add_AT_string (dw_die_ref die, enum dwarf_attribute attr_kind, const char *str)
{
  dw_attr_node attr;
  struct indirect_string_node *node;

  node = find_AT_string (str);

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_str;
  attr.dw_attr_val.v.val_str = node;
  add_dwarf_attr (die, &attr);
}

/* Create a label for an indirect string node, ensuring it is going to
   be output, unless its reference count goes down to zero.  */

static inline void
gen_label_for_indirect_string (struct indirect_string_node *node)
{
  char label[32];

  if (node->label)
    return;

  ASM_GENERATE_INTERNAL_LABEL (label, "LASF", dw2_string_counter);
  ++dw2_string_counter;
  node->label = xstrdup (label);
}

/* Create a SYMBOL_REF rtx whose value is the initial address of a
   debug string STR.  */

static inline rtx
get_debug_string_label (const char *str)
{
  struct indirect_string_node *node = find_AT_string (str);

  debug_str_hash_forced = true;

  gen_label_for_indirect_string (node);

  return gen_rtx_SYMBOL_REF (Pmode, node->label);
}

static inline const char *
AT_string (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_str);
  return a->dw_attr_val.v.val_str->str;
}

/* Find out whether a string should be output inline in DIE
   or out-of-line in .debug_str section.  */

static enum dwarf_form
AT_string_form (dw_attr_ref a)
{
  struct indirect_string_node *node;
  unsigned int len;

  gcc_assert (a && AT_class (a) == dw_val_class_str);

  node = a->dw_attr_val.v.val_str;
  if (node->form)
    return node->form;

  len = strlen (node->str) + 1;

  /* If the string is shorter or equal to the size of the reference, it is
     always better to put it inline.  */
  if (len <= DWARF_OFFSET_SIZE || node->refcount == 0)
    return node->form = DW_FORM_string;

  /* If we cannot expect the linker to merge strings in .debug_str
     section, only put it into .debug_str if it is worth even in this
     single module.  */
  if (DWARF2_INDIRECT_STRING_SUPPORT_MISSING_ON_TARGET
      || ((debug_str_section->common.flags & SECTION_MERGE) == 0
      && (len - DWARF_OFFSET_SIZE) * node->refcount <= len))
    return node->form = DW_FORM_string;

  gen_label_for_indirect_string (node);

  return node->form = DW_FORM_strp;
}

/* Add a DIE reference attribute value to a DIE.  */

static inline void
add_AT_die_ref (dw_die_ref die, enum dwarf_attribute attr_kind, dw_die_ref targ_die)
{
  dw_attr_node attr;

#ifdef ENABLE_CHECKING
  gcc_assert (targ_die != NULL);
#else
  /* With LTO we can end up trying to reference something we didn't create
     a DIE for.  Avoid crashing later on a NULL referenced DIE.  */
  if (targ_die == NULL)
    return;
#endif

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_die_ref;
  attr.dw_attr_val.v.val_die_ref.die = targ_die;
  attr.dw_attr_val.v.val_die_ref.external = 0;
  add_dwarf_attr (die, &attr);
}

/* Add an AT_specification attribute to a DIE, and also make the back
   pointer from the specification to the definition.  */

static inline void
add_AT_specification (dw_die_ref die, dw_die_ref targ_die)
{
  add_AT_die_ref (die, DW_AT_specification, targ_die);
  gcc_assert (!targ_die->die_definition);
  targ_die->die_definition = die;
}

static inline dw_die_ref
AT_ref (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_die_ref);
  return a->dw_attr_val.v.val_die_ref.die;
}

static inline int
AT_ref_external (dw_attr_ref a)
{
  if (a && AT_class (a) == dw_val_class_die_ref)
    return a->dw_attr_val.v.val_die_ref.external;

  return 0;
}

static inline void
set_AT_ref_external (dw_attr_ref a, int i)
{
  gcc_assert (a && AT_class (a) == dw_val_class_die_ref);
  a->dw_attr_val.v.val_die_ref.external = i;
}

/* Add an FDE reference attribute value to a DIE.  */

static inline void
add_AT_fde_ref (dw_die_ref die, enum dwarf_attribute attr_kind, unsigned int targ_fde)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_fde_ref;
  attr.dw_attr_val.v.val_fde_index = targ_fde;
  add_dwarf_attr (die, &attr);
}

/* Add a location description attribute value to a DIE.  */

static inline void
add_AT_loc (dw_die_ref die, enum dwarf_attribute attr_kind, dw_loc_descr_ref loc)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_loc;
  attr.dw_attr_val.v.val_loc = loc;
  add_dwarf_attr (die, &attr);
}

static inline dw_loc_descr_ref
AT_loc (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_loc);
  return a->dw_attr_val.v.val_loc;
}

static inline void
add_AT_loc_list (dw_die_ref die, enum dwarf_attribute attr_kind, dw_loc_list_ref loc_list)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_loc_list;
  attr.dw_attr_val.v.val_loc_list = loc_list;
  add_dwarf_attr (die, &attr);
  have_location_lists = true;
}

static inline dw_loc_list_ref
AT_loc_list (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_loc_list);
  return a->dw_attr_val.v.val_loc_list;
}

static inline dw_loc_list_ref *
AT_loc_list_ptr (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_loc_list);
  return &a->dw_attr_val.v.val_loc_list;
}

/* Add an address constant attribute value to a DIE.  */

static inline void
add_AT_addr (dw_die_ref die, enum dwarf_attribute attr_kind, rtx addr)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_addr;
  attr.dw_attr_val.v.val_addr = addr;
  add_dwarf_attr (die, &attr);
}

/* Get the RTX from to an address DIE attribute.  */

static inline rtx
AT_addr (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_addr);
  return a->dw_attr_val.v.val_addr;
}

/* Add a file attribute value to a DIE.  */

static inline void
add_AT_file (dw_die_ref die, enum dwarf_attribute attr_kind,
             struct dwarf_file_data *fd)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_file;
  attr.dw_attr_val.v.val_file = fd;
  add_dwarf_attr (die, &attr);
}

/* Get the dwarf_file_data from a file DIE attribute.  */

static inline struct dwarf_file_data *
AT_file (dw_attr_ref a)
{
  gcc_assert (a && AT_class (a) == dw_val_class_file);
  return a->dw_attr_val.v.val_file;
}

/* Add a vms delta attribute value to a DIE.  */

static inline void
add_AT_vms_delta (dw_die_ref die, enum dwarf_attribute attr_kind,
                  const char *lbl1, const char *lbl2)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_vms_delta;
  attr.dw_attr_val.v.val_vms_delta.lbl1 = xstrdup (lbl1);
  attr.dw_attr_val.v.val_vms_delta.lbl2 = xstrdup (lbl2);
  add_dwarf_attr (die, &attr);
}

/* Add a label identifier attribute value to a DIE.  */

static inline void
add_AT_lbl_id (dw_die_ref die, enum dwarf_attribute attr_kind, const char *lbl_id)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_lbl_id;
  attr.dw_attr_val.v.val_lbl_id = xstrdup (lbl_id);
  add_dwarf_attr (die, &attr);
}

/* Add a section offset attribute value to a DIE, an offset into the
   debug_line section.  */

static inline void
add_AT_lineptr (dw_die_ref die, enum dwarf_attribute attr_kind,
                const char *label)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_lineptr;
  attr.dw_attr_val.v.val_lbl_id = xstrdup (label);
  add_dwarf_attr (die, &attr);
}

/* Add a section offset attribute value to a DIE, an offset into the
   debug_macinfo section.  */

static inline void
add_AT_macptr (dw_die_ref die, enum dwarf_attribute attr_kind,
               const char *label)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_macptr;
  attr.dw_attr_val.v.val_lbl_id = xstrdup (label);
  add_dwarf_attr (die, &attr);
}

/* Add an offset attribute value to a DIE.  */

static inline void
add_AT_offset (dw_die_ref die, enum dwarf_attribute attr_kind,
               unsigned HOST_WIDE_INT offset)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_offset;
  attr.dw_attr_val.v.val_offset = offset;
  add_dwarf_attr (die, &attr);
}

/* Add an range_list attribute value to a DIE.  */

static void
add_AT_range_list (dw_die_ref die, enum dwarf_attribute attr_kind,
                   long unsigned int offset)
{
  dw_attr_node attr;

  attr.dw_attr = attr_kind;
  attr.dw_attr_val.val_class = dw_val_class_range_list;
  attr.dw_attr_val.v.val_offset = offset;
  add_dwarf_attr (die, &attr);
}

/* Return the start label of a delta attribute.  */

static inline const char *
AT_vms_delta1 (dw_attr_ref a)
{
  gcc_assert (a && (AT_class (a) == dw_val_class_vms_delta));
  return a->dw_attr_val.v.val_vms_delta.lbl1;
}

/* Return the end label of a delta attribute.  */

static inline const char *
AT_vms_delta2 (dw_attr_ref a)
{
  gcc_assert (a && (AT_class (a) == dw_val_class_vms_delta));
  return a->dw_attr_val.v.val_vms_delta.lbl2;
}

static inline const char *
AT_lbl (dw_attr_ref a)
{
  gcc_assert (a && (AT_class (a) == dw_val_class_lbl_id
                    || AT_class (a) == dw_val_class_lineptr
                    || AT_class (a) == dw_val_class_macptr));
  return a->dw_attr_val.v.val_lbl_id;
}

/* Get the attribute of type attr_kind.  */

static dw_attr_ref
get_AT (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a;
  unsigned ix;
  dw_die_ref spec = NULL;

  if (! die)
    return NULL;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (a->dw_attr == attr_kind)
      return a;
    else if (a->dw_attr == DW_AT_specification
             || a->dw_attr == DW_AT_abstract_origin)
      spec = AT_ref (a);

  if (spec)
    return get_AT (spec, attr_kind);

  return NULL;
}

/* Return the "low pc" attribute value, typically associated with a subprogram
   DIE.  Return null if the "low pc" attribute is either not present, or if it
   cannot be represented as an assembler label identifier.  */

static inline const char *
get_AT_low_pc (dw_die_ref die)
{
  dw_attr_ref a = get_AT (die, DW_AT_low_pc);

  return a ? AT_lbl (a) : NULL;
}

/* Return the "high pc" attribute value, typically associated with a subprogram
   DIE.  Return null if the "high pc" attribute is either not present, or if it
   cannot be represented as an assembler label identifier.  */

static inline const char *
get_AT_hi_pc (dw_die_ref die)
{
  dw_attr_ref a = get_AT (die, DW_AT_high_pc);

  return a ? AT_lbl (a) : NULL;
}

/* Return the value of the string attribute designated by ATTR_KIND, or
   NULL if it is not present.  */

static inline const char *
get_AT_string (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a = get_AT (die, attr_kind);

  return a ? AT_string (a) : NULL;
}

/* Return the value of the flag attribute designated by ATTR_KIND, or -1
   if it is not present.  */

static inline int
get_AT_flag (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a = get_AT (die, attr_kind);

  return a ? AT_flag (a) : 0;
}

/* Return the value of the unsigned attribute designated by ATTR_KIND, or 0
   if it is not present.  */

static inline unsigned
get_AT_unsigned (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a = get_AT (die, attr_kind);

  return a ? AT_unsigned (a) : 0;
}

static inline dw_die_ref
get_AT_ref (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a = get_AT (die, attr_kind);

  return a ? AT_ref (a) : NULL;
}

static inline struct dwarf_file_data *
get_AT_file (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a = get_AT (die, attr_kind);

  return a ? AT_file (a) : NULL;
}

/* Return TRUE if the language is C++.  */

static inline bool
is_cxx (void)
{
  unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);

  return lang == DW_LANG_C_plus_plus || lang == DW_LANG_ObjC_plus_plus;
}

/* Return TRUE if the language is Fortran.  */

static inline bool
is_fortran (void)
{
  unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);

  return (lang == DW_LANG_Fortran77
          || lang == DW_LANG_Fortran90
          || lang == DW_LANG_Fortran95);
}

/* Return TRUE if the language is Ada.  */

static inline bool
is_ada (void)
{
  unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);

  return lang == DW_LANG_Ada95 || lang == DW_LANG_Ada83;
}

/* Remove the specified attribute if present.  */

static void
remove_AT (dw_die_ref die, enum dwarf_attribute attr_kind)
{
  dw_attr_ref a;
  unsigned ix;

  if (! die)
    return;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (a->dw_attr == attr_kind)
      {
        if (AT_class (a) == dw_val_class_str)
          if (a->dw_attr_val.v.val_str->refcount)
            a->dw_attr_val.v.val_str->refcount--;

        /* VEC_ordered_remove should help reduce the number of abbrevs
           that are needed.  */
        VEC_ordered_remove (dw_attr_node, die->die_attr, ix);
        return;
      }
}

/* Remove CHILD from its parent.  PREV must have the property that
   PREV->DIE_SIB == CHILD.  Does not alter CHILD.  */

static void
remove_child_with_prev (dw_die_ref child, dw_die_ref prev)
{
  gcc_assert (child->die_parent == prev->die_parent);
  gcc_assert (prev->die_sib == child);
  if (prev == child)
    {
      gcc_assert (child->die_parent->die_child == child);
      prev = NULL;
    }
  else
    prev->die_sib = child->die_sib;
  if (child->die_parent->die_child == child)
    child->die_parent->die_child = prev;
}

/* Replace OLD_CHILD with NEW_CHILD.  PREV must have the property that
   PREV->DIE_SIB == OLD_CHILD.  Does not alter OLD_CHILD.  */

static void
replace_child (dw_die_ref old_child, dw_die_ref new_child, dw_die_ref prev)
{
  dw_die_ref parent = old_child->die_parent;

  gcc_assert (parent == prev->die_parent);
  gcc_assert (prev->die_sib == old_child);

  new_child->die_parent = parent;
  if (prev == old_child)
    {
      gcc_assert (parent->die_child == old_child);
      new_child->die_sib = new_child;
    }
  else
    {
      prev->die_sib = new_child;
      new_child->die_sib = old_child->die_sib;
    }
  if (old_child->die_parent->die_child == old_child)
    old_child->die_parent->die_child = new_child;
}

/* Move all children from OLD_PARENT to NEW_PARENT.  */

static void
move_all_children (dw_die_ref old_parent, dw_die_ref new_parent)
{
  dw_die_ref c;
  new_parent->die_child = old_parent->die_child;
  old_parent->die_child = NULL;
  FOR_EACH_CHILD (new_parent, c, c->die_parent = new_parent);
}

/* Remove child DIE whose die_tag is TAG.  Do nothing if no child
   matches TAG.  */

static void
remove_child_TAG (dw_die_ref die, enum dwarf_tag tag)
{
  dw_die_ref c;

  c = die->die_child;
  if (c) do {
    dw_die_ref prev = c;
    c = c->die_sib;
    while (c->die_tag == tag)
      {
        remove_child_with_prev (c, prev);
        /* Might have removed every child.  */
        if (c == c->die_sib)
          return;
        c = c->die_sib;
      }
  } while (c != die->die_child);
}

/* Add a CHILD_DIE as the last child of DIE.  */

static void
add_child_die (dw_die_ref die, dw_die_ref child_die)
{
  /* FIXME this should probably be an assert.  */
  if (! die || ! child_die)
    return;
  gcc_assert (die != child_die);

  child_die->die_parent = die;
  if (die->die_child)
    {
      child_die->die_sib = die->die_child->die_sib;
      die->die_child->die_sib = child_die;
    }
  else
    child_die->die_sib = child_die;
  die->die_child = child_die;
}

/* Move CHILD, which must be a child of PARENT or the DIE for which PARENT
   is the specification, to the end of PARENT's list of children.
   This is done by removing and re-adding it.  */

static void
splice_child_die (dw_die_ref parent, dw_die_ref child)
{
  dw_die_ref p;

  /* We want the declaration DIE from inside the class, not the
     specification DIE at toplevel.  */
  if (child->die_parent != parent)
    {
      dw_die_ref tmp = get_AT_ref (child, DW_AT_specification);

      if (tmp)
        child = tmp;
    }

  gcc_assert (child->die_parent == parent
              || (child->die_parent
                  == get_AT_ref (parent, DW_AT_specification)));

  for (p = child->die_parent->die_child; ; p = p->die_sib)
    if (p->die_sib == child)
      {
        remove_child_with_prev (child, p);
        break;
      }

  add_child_die (parent, child);
}

/* Return a pointer to a newly created DIE node.  */

static inline dw_die_ref
new_die (enum dwarf_tag tag_value, dw_die_ref parent_die, tree t)
{
  dw_die_ref die = ggc_alloc_cleared_die_node ();

  die->die_tag = tag_value;

  if (parent_die != NULL)
    add_child_die (parent_die, die);
  else
    {
      limbo_die_node *limbo_node;

      limbo_node = ggc_alloc_cleared_limbo_die_node ();
      limbo_node->die = die;
      limbo_node->created_for = t;
      limbo_node->next = limbo_die_list;
      limbo_die_list = limbo_node;
    }

  return die;
}

/* Return the DIE associated with the given type specifier.  */

static inline dw_die_ref
lookup_type_die (tree type)
{
  return TYPE_SYMTAB_DIE (type);
}

/* Like lookup_type_die, but if type is an anonymous type named by a
   typedef[1], return the DIE of the anonymous type instead the one of
   the naming typedef.  This is because in gen_typedef_die, we did
   equate the anonymous struct named by the typedef with the DIE of
   the naming typedef. So by default, lookup_type_die on an anonymous
   struct yields the DIE of the naming typedef.

   [1]: Read the comment of is_naming_typedef_decl to learn about what
   a naming typedef is.  */

static inline dw_die_ref
lookup_type_die_strip_naming_typedef (tree type)
{
  dw_die_ref die = lookup_type_die (type);
  if (TREE_CODE (type) == RECORD_TYPE
      && die->die_tag == DW_TAG_typedef
      && is_naming_typedef_decl (TYPE_NAME (type)))
    die = get_AT_ref (die, DW_AT_type);
  return die;
}

/* Equate a DIE to a given type specifier.  */

static inline void
equate_type_number_to_die (tree type, dw_die_ref type_die)
{
  TYPE_SYMTAB_DIE (type) = type_die;
}

/* Returns a hash value for X (which really is a die_struct).  */

static hashval_t
decl_die_table_hash (const void *x)
{
  return (hashval_t) ((const_dw_die_ref) x)->decl_id;
}

/* Return nonzero if decl_id of die_struct X is the same as UID of decl *Y.  */

static int
decl_die_table_eq (const void *x, const void *y)
{
  return (((const_dw_die_ref) x)->decl_id == DECL_UID ((const_tree) y));
}

/* Return the DIE associated with a given declaration.  */

static inline dw_die_ref
lookup_decl_die (tree decl)
{
  return (dw_die_ref) htab_find_with_hash (decl_die_table, decl, DECL_UID (decl));
}

/* Returns a hash value for X (which really is a var_loc_list).  */

static hashval_t
decl_loc_table_hash (const void *x)
{
  return (hashval_t) ((const var_loc_list *) x)->decl_id;
}

/* Return nonzero if decl_id of var_loc_list X is the same as
   UID of decl *Y.  */

static int
decl_loc_table_eq (const void *x, const void *y)
{
  return (((const var_loc_list *) x)->decl_id == DECL_UID ((const_tree) y));
}

/* Return the var_loc list associated with a given declaration.  */

static inline var_loc_list *
lookup_decl_loc (const_tree decl)
{
  if (!decl_loc_table)
    return NULL;
  return (var_loc_list *)
    htab_find_with_hash (decl_loc_table, decl, DECL_UID (decl));
}

/* Equate a DIE to a particular declaration.  */

static void
equate_decl_number_to_die (tree decl, dw_die_ref decl_die)
{
  unsigned int decl_id = DECL_UID (decl);
  void **slot;

  slot = htab_find_slot_with_hash (decl_die_table, decl, decl_id, INSERT);
  *slot = decl_die;
  decl_die->decl_id = decl_id;
}

/* Return how many bits covers PIECE EXPR_LIST.  */

static int
decl_piece_bitsize (rtx piece)
{
  int ret = (int) GET_MODE (piece);
  if (ret)
    return ret;
  gcc_assert (GET_CODE (XEXP (piece, 0)) == CONCAT
              && CONST_INT_P (XEXP (XEXP (piece, 0), 0)));
  return INTVAL (XEXP (XEXP (piece, 0), 0));
}

/* Return pointer to the location of location note in PIECE EXPR_LIST.  */

static rtx *
decl_piece_varloc_ptr (rtx piece)
{
  if ((int) GET_MODE (piece))
    return &XEXP (piece, 0);
  else
    return &XEXP (XEXP (piece, 0), 1);
}

/* Create an EXPR_LIST for location note LOC_NOTE covering BITSIZE bits.
   Next is the chain of following piece nodes.  */

static rtx
decl_piece_node (rtx loc_note, HOST_WIDE_INT bitsize, rtx next)
{
  if (bitsize <= (int) MAX_MACHINE_MODE)
    return alloc_EXPR_LIST (bitsize, loc_note, next);
  else
    return alloc_EXPR_LIST (0, gen_rtx_CONCAT (VOIDmode,
                                               GEN_INT (bitsize),
                                               loc_note), next);
}

/* Return rtx that should be stored into loc field for
   LOC_NOTE and BITPOS/BITSIZE.  */

static rtx
construct_piece_list (rtx loc_note, HOST_WIDE_INT bitpos,
                      HOST_WIDE_INT bitsize)
{
  if (bitsize != -1)
    {
      loc_note = decl_piece_node (loc_note, bitsize, NULL_RTX);
      if (bitpos != 0)
        loc_note = decl_piece_node (NULL_RTX, bitpos, loc_note);
    }
  return loc_note;
}

/* This function either modifies location piece list *DEST in
   place (if SRC and INNER is NULL), or copies location piece list
   *SRC to *DEST while modifying it.  Location BITPOS is modified
   to contain LOC_NOTE, any pieces overlapping it are removed resp.
   not copied and if needed some padding around it is added.
   When modifying in place, DEST should point to EXPR_LIST where
   earlier pieces cover PIECE_BITPOS bits, when copying SRC points
   to the start of the whole list and INNER points to the EXPR_LIST
   where earlier pieces cover PIECE_BITPOS bits.  */

static void
adjust_piece_list (rtx *dest, rtx *src, rtx *inner,
                   HOST_WIDE_INT bitpos, HOST_WIDE_INT piece_bitpos,
                   HOST_WIDE_INT bitsize, rtx loc_note)
{
  int diff;
  bool copy = inner != NULL;

  if (copy)
    {
      /* First copy all nodes preceeding the current bitpos.  */
      while (src != inner)
        {
          *dest = decl_piece_node (*decl_piece_varloc_ptr (*src),
                                   decl_piece_bitsize (*src), NULL_RTX);
          dest = &XEXP (*dest, 1);
          src = &XEXP (*src, 1);
        }
    }
  /* Add padding if needed.  */
  if (bitpos != piece_bitpos)
    {
      *dest = decl_piece_node (NULL_RTX, bitpos - piece_bitpos,
                               copy ? NULL_RTX : *dest);
      dest = &XEXP (*dest, 1);
    }
  else if (*dest && decl_piece_bitsize (*dest) == bitsize)
    {
      gcc_assert (!copy);
      /* A piece with correct bitpos and bitsize already exist,
         just update the location for it and return.  */
      *decl_piece_varloc_ptr (*dest) = loc_note;
      return;
    }
  /* Add the piece that changed.  */
  *dest = decl_piece_node (loc_note, bitsize, copy ? NULL_RTX : *dest);
  dest = &XEXP (*dest, 1);
  /* Skip over pieces that overlap it.  */
  diff = bitpos - piece_bitpos + bitsize;
  if (!copy)
    src = dest;
  while (diff > 0 && *src)
    {
      rtx piece = *src;
      diff -= decl_piece_bitsize (piece);
      if (copy)
        src = &XEXP (piece, 1);
      else
        {
          *src = XEXP (piece, 1);
          free_EXPR_LIST_node (piece);
        }
    }
  /* Add padding if needed.  */
  if (diff < 0 && *src)
    {
      if (!copy)
        dest = src;
      *dest = decl_piece_node (NULL_RTX, -diff, copy ? NULL_RTX : *dest);
      dest = &XEXP (*dest, 1);
    }
  if (!copy)
    return;
  /* Finally copy all nodes following it.  */
  while (*src)
    {
      *dest = decl_piece_node (*decl_piece_varloc_ptr (*src),
                               decl_piece_bitsize (*src), NULL_RTX);
      dest = &XEXP (*dest, 1);
      src = &XEXP (*src, 1);
    }
}

/* Add a variable location node to the linked list for DECL.  */

static struct var_loc_node *
add_var_loc_to_decl (tree decl, rtx loc_note, const char *label)
{
  unsigned int decl_id;
  var_loc_list *temp;
  void **slot;
  struct var_loc_node *loc = NULL;
  HOST_WIDE_INT bitsize = -1, bitpos = -1;

  if (DECL_DEBUG_EXPR_IS_FROM (decl))
    {
      tree realdecl = DECL_DEBUG_EXPR (decl);
      if (realdecl && handled_component_p (realdecl))
        {
          HOST_WIDE_INT maxsize;
          tree innerdecl;
          innerdecl
            = get_ref_base_and_extent (realdecl, &bitpos, &bitsize, &maxsize);
          if (!DECL_P (innerdecl)
              || DECL_IGNORED_P (innerdecl)
              || TREE_STATIC (innerdecl)
              || bitsize <= 0
              || bitpos + bitsize > 256
              || bitsize != maxsize)
            return NULL;
          decl = innerdecl;
        }
    }

  decl_id = DECL_UID (decl);
  slot = htab_find_slot_with_hash (decl_loc_table, decl, decl_id, INSERT);
  if (*slot == NULL)
    {
      temp = ggc_alloc_cleared_var_loc_list ();
      temp->decl_id = decl_id;
      *slot = temp;
    }
  else
    temp = (var_loc_list *) *slot;

  if (temp->last)
    {
      struct var_loc_node *last = temp->last, *unused = NULL;
      rtx *piece_loc = NULL, last_loc_note;
      int piece_bitpos = 0;
      if (last->next)
        {
          last = last->next;
          gcc_assert (last->next == NULL);
        }
      if (bitsize != -1 && GET_CODE (last->loc) == EXPR_LIST)
        {
          piece_loc = &last->loc;
          do
            {
              int cur_bitsize = decl_piece_bitsize (*piece_loc);
              if (piece_bitpos + cur_bitsize > bitpos)
                break;
              piece_bitpos += cur_bitsize;
              piece_loc = &XEXP (*piece_loc, 1);
            }
          while (*piece_loc);
        }
      /* TEMP->LAST here is either pointer to the last but one or
         last element in the chained list, LAST is pointer to the
         last element.  */
      if (label && strcmp (last->label, label) == 0)
        {
          /* For SRA optimized variables if there weren't any real
             insns since last note, just modify the last node.  */
          if (piece_loc != NULL)
            {
              adjust_piece_list (piece_loc, NULL, NULL,
                                 bitpos, piece_bitpos, bitsize, loc_note);
              return NULL;
            }
          /* If the last note doesn't cover any instructions, remove it.  */
          if (temp->last != last)
            {
              temp->last->next = NULL;
              unused = last;
              last = temp->last;
              gcc_assert (strcmp (last->label, label) != 0);
            }
          else
            {
              gcc_assert (temp->first == temp->last);
              memset (temp->last, '\0', sizeof (*temp->last));
              temp->last->loc = construct_piece_list (loc_note, bitpos, bitsize);
              return temp->last;
            }
        }
      if (bitsize == -1 && NOTE_P (last->loc))
        last_loc_note = last->loc;
      else if (piece_loc != NULL
               && *piece_loc != NULL_RTX
               && piece_bitpos == bitpos
               && decl_piece_bitsize (*piece_loc) == bitsize)
        last_loc_note = *decl_piece_varloc_ptr (*piece_loc);
      else
        last_loc_note = NULL_RTX;
      /* If the current location is the same as the end of the list,
         and either both or neither of the locations is uninitialized,
         we have nothing to do.  */
      if (last_loc_note == NULL_RTX
          || (!rtx_equal_p (NOTE_VAR_LOCATION_LOC (last_loc_note),
                            NOTE_VAR_LOCATION_LOC (loc_note)))
          || ((NOTE_VAR_LOCATION_STATUS (last_loc_note)
               != NOTE_VAR_LOCATION_STATUS (loc_note))
              && ((NOTE_VAR_LOCATION_STATUS (last_loc_note)
                   == VAR_INIT_STATUS_UNINITIALIZED)
                  || (NOTE_VAR_LOCATION_STATUS (loc_note)
                      == VAR_INIT_STATUS_UNINITIALIZED))))
        {
          /* Add LOC to the end of list and update LAST.  If the last
             element of the list has been removed above, reuse its
             memory for the new node, otherwise allocate a new one.  */
          if (unused)
            {
              loc = unused;
              memset (loc, '\0', sizeof (*loc));
            }
          else
            loc = ggc_alloc_cleared_var_loc_node ();
          if (bitsize == -1 || piece_loc == NULL)
            loc->loc = construct_piece_list (loc_note, bitpos, bitsize);
          else
            adjust_piece_list (&loc->loc, &last->loc, piece_loc,
                               bitpos, piece_bitpos, bitsize, loc_note);
          last->next = loc;
          /* Ensure TEMP->LAST will point either to the new last but one
             element of the chain, or to the last element in it.  */
          if (last != temp->last)
            temp->last = last;
        }
      else if (unused)
        ggc_free (unused);
    }
  else
    {
      loc = ggc_alloc_cleared_var_loc_node ();
      temp->first = loc;
      temp->last = loc;
      loc->loc = construct_piece_list (loc_note, bitpos, bitsize);
    }
  return loc;
}
\f
/* Keep track of the number of spaces used to indent the
   output of the debugging routines that print the structure of
   the DIE internal representation.  */
static int print_indent;

/* Indent the line the number of spaces given by print_indent.  */

static inline void
print_spaces (FILE *outfile)
{
  fprintf (outfile, "%*s", print_indent, "");
}

/* Print a type signature in hex.  */

static inline void
print_signature (FILE *outfile, char *sig)
{
  int i;

  for (i = 0; i < DWARF_TYPE_SIGNATURE_SIZE; i++)
    fprintf (outfile, "%02x", sig[i] & 0xff);
}

/* Print the information associated with a given DIE, and its children.
   This routine is a debugging aid only.  */

static void
print_die (dw_die_ref die, FILE *outfile)
{
  dw_attr_ref a;
  dw_die_ref c;
  unsigned ix;

  print_spaces (outfile);
  fprintf (outfile, "DIE %4ld: %s (%p)\n",
           die->die_offset, dwarf_tag_name (die->die_tag),
           (void*) die);
  print_spaces (outfile);
  fprintf (outfile, "  abbrev id: %lu", die->die_abbrev);
  fprintf (outfile, " offset: %ld", die->die_offset);
  fprintf (outfile, " mark: %d\n", die->die_mark);

  if (dwarf_version >= 4 && die->die_id.die_type_node)
    {
      print_spaces (outfile);
      fprintf (outfile, "  signature: ");
      print_signature (outfile, die->die_id.die_type_node->signature);
      fprintf (outfile, "\n");
    }

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      print_spaces (outfile);
      fprintf (outfile, "  %s: ", dwarf_attr_name (a->dw_attr));

      switch (AT_class (a))
        {
        case dw_val_class_addr:
          fprintf (outfile, "address");
          break;
        case dw_val_class_offset:
          fprintf (outfile, "offset");
          break;
        case dw_val_class_loc:
          fprintf (outfile, "location descriptor");
          break;
        case dw_val_class_loc_list:
          fprintf (outfile, "location list -> label:%s",
                   AT_loc_list (a)->ll_symbol);
          break;
        case dw_val_class_range_list:
          fprintf (outfile, "range list");
          break;
        case dw_val_class_const:
          fprintf (outfile, HOST_WIDE_INT_PRINT_DEC, AT_int (a));
          break;
        case dw_val_class_unsigned_const:
          fprintf (outfile, HOST_WIDE_INT_PRINT_UNSIGNED, AT_unsigned (a));
          break;
        case dw_val_class_const_double:
          fprintf (outfile, "constant ("HOST_WIDE_INT_PRINT_DEC","\
                            HOST_WIDE_INT_PRINT_UNSIGNED")",
                   a->dw_attr_val.v.val_double.high,
                   a->dw_attr_val.v.val_double.low);
          break;
        case dw_val_class_vec:
          fprintf (outfile, "floating-point or vector constant");
          break;
        case dw_val_class_flag:
          fprintf (outfile, "%u", AT_flag (a));
          break;
        case dw_val_class_die_ref:
          if (AT_ref (a) != NULL)
            {
              if (dwarf_version >= 4 && AT_ref (a)->die_id.die_type_node)
                {
                  fprintf (outfile, "die -> signature: ");
                  print_signature (outfile,
                                   AT_ref (a)->die_id.die_type_node->signature);
                }
              else if (dwarf_version < 4 && AT_ref (a)->die_id.die_symbol)
                fprintf (outfile, "die -> label: %s",
                         AT_ref (a)->die_id.die_symbol);
              else
                fprintf (outfile, "die -> %ld", AT_ref (a)->die_offset);
              fprintf (outfile, " (%p)", (void *) AT_ref (a));
            }
          else
            fprintf (outfile, "die -> <null>");
          break;
        case dw_val_class_vms_delta:
          fprintf (outfile, "delta: @slotcount(%s-%s)",
                   AT_vms_delta2 (a), AT_vms_delta1 (a));
          break;
        case dw_val_class_lbl_id:
        case dw_val_class_lineptr:
        case dw_val_class_macptr:
          fprintf (outfile, "label: %s", AT_lbl (a));
          break;
        case dw_val_class_str:
          if (AT_string (a) != NULL)
            fprintf (outfile, "\"%s\"", AT_string (a));
          else
            fprintf (outfile, "<null>");
          break;
        case dw_val_class_file:
          fprintf (outfile, "\"%s\" (%d)", AT_file (a)->filename,
                   AT_file (a)->emitted_number);
          break;
        case dw_val_class_data8:
          {
            int i;

            for (i = 0; i < 8; i++)
              fprintf (outfile, "%02x", a->dw_attr_val.v.val_data8[i]);
            break;
          }
        default:
          break;
        }

      fprintf (outfile, "\n");
    }

  if (die->die_child != NULL)
    {
      print_indent += 4;
      FOR_EACH_CHILD (die, c, print_die (c, outfile));
      print_indent -= 4;
    }
  if (print_indent == 0)
    fprintf (outfile, "\n");
}

/* Print the contents of the source code line number correspondence table.
   This routine is a debugging aid only.  */

static void
print_dwarf_line_table (FILE *outfile)
{
  unsigned i;
  dw_line_info_ref line_info;

  fprintf (outfile, "\n\nDWARF source line information\n");
  for (i = 1; i < line_info_table_in_use; i++)
    {
      line_info = &line_info_table[i];
      fprintf (outfile, "%5d: %4ld %6ld\n", i,
               line_info->dw_file_num,
               line_info->dw_line_num);
    }

  fprintf (outfile, "\n\n");
}

/* Print the information collected for a given DIE.  */

DEBUG_FUNCTION void
debug_dwarf_die (dw_die_ref die)
{
  print_die (die, stderr);
}

/* Print all DWARF information collected for the compilation unit.
   This routine is a debugging aid only.  */

DEBUG_FUNCTION void
debug_dwarf (void)
{
  print_indent = 0;
  print_die (comp_unit_die (), stderr);
  if (! DWARF2_ASM_LINE_DEBUG_INFO)
    print_dwarf_line_table (stderr);
}
\f
/* Start a new compilation unit DIE for an include file.  OLD_UNIT is the CU
   for the enclosing include file, if any.  BINCL_DIE is the DW_TAG_GNU_BINCL
   DIE that marks the start of the DIEs for this include file.  */

static dw_die_ref
push_new_compile_unit (dw_die_ref old_unit, dw_die_ref bincl_die)
{
  const char *filename = get_AT_string (bincl_die, DW_AT_name);
  dw_die_ref new_unit = gen_compile_unit_die (filename);

  new_unit->die_sib = old_unit;
  return new_unit;
}

/* Close an include-file CU and reopen the enclosing one.  */

static dw_die_ref
pop_compile_unit (dw_die_ref old_unit)
{
  dw_die_ref new_unit = old_unit->die_sib;

  old_unit->die_sib = NULL;
  return new_unit;
}

#define CHECKSUM(FOO) md5_process_bytes (&(FOO), sizeof (FOO), ctx)
#define CHECKSUM_STRING(FOO) md5_process_bytes ((FOO), strlen (FOO), ctx)

/* Calculate the checksum of a location expression.  */

static inline void
loc_checksum (dw_loc_descr_ref loc, struct md5_ctx *ctx)
{
  int tem;

  tem = (loc->dtprel << 8) | ((unsigned int) loc->dw_loc_opc);
  CHECKSUM (tem);
  CHECKSUM (loc->dw_loc_oprnd1);
  CHECKSUM (loc->dw_loc_oprnd2);
}

/* Calculate the checksum of an attribute.  */

static void
attr_checksum (dw_attr_ref at, struct md5_ctx *ctx, int *mark)
{
  dw_loc_descr_ref loc;
  rtx r;

  CHECKSUM (at->dw_attr);

  /* We don't care that this was compiled with a different compiler
     snapshot; if the output is the same, that's what matters.  */
  if (at->dw_attr == DW_AT_producer)
    return;

  switch (AT_class (at))
    {
    case dw_val_class_const:
      CHECKSUM (at->dw_attr_val.v.val_int);
      break;
    case dw_val_class_unsigned_const:
      CHECKSUM (at->dw_attr_val.v.val_unsigned);
      break;
    case dw_val_class_const_double:
      CHECKSUM (at->dw_attr_val.v.val_double);
      break;
    case dw_val_class_vec:
      CHECKSUM (at->dw_attr_val.v.val_vec);
      break;
    case dw_val_class_flag:
      CHECKSUM (at->dw_attr_val.v.val_flag);
      break;
    case dw_val_class_str:
      CHECKSUM_STRING (AT_string (at));
      break;

    case dw_val_class_addr:
      r = AT_addr (at);
      gcc_assert (GET_CODE (r) == SYMBOL_REF);
      CHECKSUM_STRING (XSTR (r, 0));
      break;

    case dw_val_class_offset:
      CHECKSUM (at->dw_attr_val.v.val_offset);
      break;

    case dw_val_class_loc:
      for (loc = AT_loc (at); loc; loc = loc->dw_loc_next)
        loc_checksum (loc, ctx);
      break;

    case dw_val_class_die_ref:
      die_checksum (AT_ref (at), ctx, mark);
      break;

    case dw_val_class_fde_ref:
    case dw_val_class_vms_delta:
    case dw_val_class_lbl_id:
    case dw_val_class_lineptr:
    case dw_val_class_macptr:
      break;

    case dw_val_class_file:
      CHECKSUM_STRING (AT_file (at)->filename);
      break;

    case dw_val_class_data8:
      CHECKSUM (at->dw_attr_val.v.val_data8);
      break;

    default:
      break;
    }
}

/* Calculate the checksum of a DIE.  */

static void
die_checksum (dw_die_ref die, struct md5_ctx *ctx, int *mark)
{
  dw_die_ref c;
  dw_attr_ref a;
  unsigned ix;

  /* To avoid infinite recursion.  */
  if (die->die_mark)
    {
      CHECKSUM (die->die_mark);
      return;
    }
  die->die_mark = ++(*mark);

  CHECKSUM (die->die_tag);

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    attr_checksum (a, ctx, mark);

  FOR_EACH_CHILD (die, c, die_checksum (c, ctx, mark));
}

#undef CHECKSUM
#undef CHECKSUM_STRING

/* For DWARF-4 types, include the trailing NULL when checksumming strings.  */
#define CHECKSUM(FOO) md5_process_bytes (&(FOO), sizeof (FOO), ctx)
#define CHECKSUM_STRING(FOO) md5_process_bytes ((FOO), strlen (FOO) + 1, ctx)
#define CHECKSUM_SLEB128(FOO) checksum_sleb128 ((FOO), ctx)
#define CHECKSUM_ULEB128(FOO) checksum_uleb128 ((FOO), ctx)
#define CHECKSUM_ATTR(FOO) \
  if (FOO) attr_checksum_ordered (die->die_tag, (FOO), ctx, mark)

/* Calculate the checksum of a number in signed LEB128 format.  */

static void
checksum_sleb128 (HOST_WIDE_INT value, struct md5_ctx *ctx)
{
  unsigned char byte;
  bool more;

  while (1)
    {
      byte = (value & 0x7f);
      value >>= 7;
      more = !((value == 0 && (byte & 0x40) == 0)
                || (value == -1 && (byte & 0x40) != 0));
      if (more)
        byte |= 0x80;
      CHECKSUM (byte);
      if (!more)
        break;
    }
}

/* Calculate the checksum of a number in unsigned LEB128 format.  */

static void
checksum_uleb128 (unsigned HOST_WIDE_INT value, struct md5_ctx *ctx)
{
  while (1)
    {
      unsigned char byte = (value & 0x7f);
      value >>= 7;
      if (value != 0)
        /* More bytes to follow.  */
        byte |= 0x80;
      CHECKSUM (byte);
      if (value == 0)
        break;
    }
}

/* Checksum the context of the DIE.  This adds the names of any
   surrounding namespaces or structures to the checksum.  */

static void
checksum_die_context (dw_die_ref die, struct md5_ctx *ctx)
{
  const char *name;
  dw_die_ref spec;
  int tag = die->die_tag;

  if (tag != DW_TAG_namespace
      && tag != DW_TAG_structure_type
      && tag != DW_TAG_class_type)
    return;

  name = get_AT_string (die, DW_AT_name);

  spec = get_AT_ref (die, DW_AT_specification);
  if (spec != NULL)
    die = spec;

  if (die->die_parent != NULL)
    checksum_die_context (die->die_parent, ctx);

  CHECKSUM_ULEB128 ('C');
  CHECKSUM_ULEB128 (tag);
  if (name != NULL)
    CHECKSUM_STRING (name);
}

/* Calculate the checksum of a location expression.  */

static inline void
loc_checksum_ordered (dw_loc_descr_ref loc, struct md5_ctx *ctx)
{
  /* Special case for lone DW_OP_plus_uconst: checksum as if the location
     were emitted as a DW_FORM_sdata instead of a location expression.  */
  if (loc->dw_loc_opc == DW_OP_plus_uconst && loc->dw_loc_next == NULL)
    {
      CHECKSUM_ULEB128 (DW_FORM_sdata);
      CHECKSUM_SLEB128 ((HOST_WIDE_INT) loc->dw_loc_oprnd1.v.val_unsigned);
      return;
    }

  /* Otherwise, just checksum the raw location expression.  */
  while (loc != NULL)
    {
      CHECKSUM_ULEB128 (loc->dw_loc_opc);
      CHECKSUM (loc->dw_loc_oprnd1);
      CHECKSUM (loc->dw_loc_oprnd2);
      loc = loc->dw_loc_next;
    }
}

/* Calculate the checksum of an attribute.  */

static void
attr_checksum_ordered (enum dwarf_tag tag, dw_attr_ref at,
                       struct md5_ctx *ctx, int *mark)
{
  dw_loc_descr_ref loc;
  rtx r;

  if (AT_class (at) == dw_val_class_die_ref)
    {
      dw_die_ref target_die = AT_ref (at);

      /* For pointer and reference types, we checksum only the (qualified)
         name of the target type (if there is a name).  For friend entries,
         we checksum only the (qualified) name of the target type or function.
         This allows the checksum to remain the same whether the target type
         is complete or not.  */
      if ((at->dw_attr == DW_AT_type
           && (tag == DW_TAG_pointer_type
               || tag == DW_TAG_reference_type
               || tag == DW_TAG_rvalue_reference_type
               || tag == DW_TAG_ptr_to_member_type))
          || (at->dw_attr == DW_AT_friend
              && tag == DW_TAG_friend))
        {
          dw_attr_ref name_attr = get_AT (target_die, DW_AT_name);

          if (name_attr != NULL)
            {
              dw_die_ref decl = get_AT_ref (target_die, DW_AT_specification);

              if (decl == NULL)
                decl = target_die;
              CHECKSUM_ULEB128 ('N');
              CHECKSUM_ULEB128 (at->dw_attr);
              if (decl->die_parent != NULL)
                checksum_die_context (decl->die_parent, ctx);
              CHECKSUM_ULEB128 ('E');
              CHECKSUM_STRING (AT_string (name_attr));
              return;
            }
        }

      /* For all other references to another DIE, we check to see if the
         target DIE has already been visited.  If it has, we emit a
         backward reference; if not, we descend recursively.  */
      if (target_die->die_mark > 0)
        {
          CHECKSUM_ULEB128 ('R');
          CHECKSUM_ULEB128 (at->dw_attr);
          CHECKSUM_ULEB128 (target_die->die_mark);
        }
      else
        {
          dw_die_ref decl = get_AT_ref (target_die, DW_AT_specification);

          if (decl == NULL)
            decl = target_die;
          target_die->die_mark = ++(*mark);
          CHECKSUM_ULEB128 ('T');
          CHECKSUM_ULEB128 (at->dw_attr);
          if (decl->die_parent != NULL)
            checksum_die_context (decl->die_parent, ctx);
          die_checksum_ordered (target_die, ctx, mark);
        }
      return;
    }

  CHECKSUM_ULEB128 ('A');
  CHECKSUM_ULEB128 (at->dw_attr);

  switch (AT_class (at))
    {
    case dw_val_class_const:
      CHECKSUM_ULEB128 (DW_FORM_sdata);
      CHECKSUM_SLEB128 (at->dw_attr_val.v.val_int);
      break;

    case dw_val_class_unsigned_const:
      CHECKSUM_ULEB128 (DW_FORM_sdata);
      CHECKSUM_SLEB128 ((int) at->dw_attr_val.v.val_unsigned);
      break;

    case dw_val_class_const_double:
      CHECKSUM_ULEB128 (DW_FORM_block);
      CHECKSUM_ULEB128 (sizeof (at->dw_attr_val.v.val_double));
      CHECKSUM (at->dw_attr_val.v.val_double);
      break;

    case dw_val_class_vec:
      CHECKSUM_ULEB128 (DW_FORM_block);
      CHECKSUM_ULEB128 (sizeof (at->dw_attr_val.v.val_vec));
      CHECKSUM (at->dw_attr_val.v.val_vec);
      break;

    case dw_val_class_flag:
      CHECKSUM_ULEB128 (DW_FORM_flag);
      CHECKSUM_ULEB128 (at->dw_attr_val.v.val_flag ? 1 : 0);
      break;

    case dw_val_class_str:
      CHECKSUM_ULEB128 (DW_FORM_string);
      CHECKSUM_STRING (AT_string (at));
      break;

    case dw_val_class_addr:
      r = AT_addr (at);
      gcc_assert (GET_CODE (r) == SYMBOL_REF);
      CHECKSUM_ULEB128 (DW_FORM_string);
      CHECKSUM_STRING (XSTR (r, 0));
      break;

    case dw_val_class_offset:
      CHECKSUM_ULEB128 (DW_FORM_sdata);
      CHECKSUM_ULEB128 (at->dw_attr_val.v.val_offset);
      break;

    case dw_val_class_loc:
      for (loc = AT_loc (at); loc; loc = loc->dw_loc_next)
        loc_checksum_ordered (loc, ctx);
      break;

    case dw_val_class_fde_ref:
    case dw_val_class_lbl_id:
    case dw_val_class_lineptr:
    case dw_val_class_macptr:
      break;

    case dw_val_class_file:
      CHECKSUM_ULEB128 (DW_FORM_string);
      CHECKSUM_STRING (AT_file (at)->filename);
      break;

    case dw_val_class_data8:
      CHECKSUM (at->dw_attr_val.v.val_data8);
      break;

    default:
      break;
    }
}

struct checksum_attributes
{
  dw_attr_ref at_name;
  dw_attr_ref at_type;
  dw_attr_ref at_friend;
  dw_attr_ref at_accessibility;
  dw_attr_ref at_address_class;
  dw_attr_ref at_allocated;
  dw_attr_ref at_artificial;
  dw_attr_ref at_associated;
  dw_attr_ref at_binary_scale;
  dw_attr_ref at_bit_offset;
  dw_attr_ref at_bit_size;
  dw_attr_ref at_bit_stride;
  dw_attr_ref at_byte_size;
  dw_attr_ref at_byte_stride;
  dw_attr_ref at_const_value;
  dw_attr_ref at_containing_type;
  dw_attr_ref at_count;
  dw_attr_ref at_data_location;
  dw_attr_ref at_data_member_location;
  dw_attr_ref at_decimal_scale;
  dw_attr_ref at_decimal_sign;
  dw_attr_ref at_default_value;
  dw_attr_ref at_digit_count;
  dw_attr_ref at_discr;
  dw_attr_ref at_discr_list;
  dw_attr_ref at_discr_value;
  dw_attr_ref at_encoding;
  dw_attr_ref at_endianity;
  dw_attr_ref at_explicit;
  dw_attr_ref at_is_optional;
  dw_attr_ref at_location;
  dw_attr_ref at_lower_bound;
  dw_attr_ref at_mutable;
  dw_attr_ref at_ordering;
  dw_attr_ref at_picture_string;
  dw_attr_ref at_prototyped;
  dw_attr_ref at_small;
  dw_attr_ref at_segment;
  dw_attr_ref at_string_length;
  dw_attr_ref at_threads_scaled;
  dw_attr_ref at_upper_bound;
  dw_attr_ref at_use_location;
  dw_attr_ref at_use_UTF8;
  dw_attr_ref at_variable_parameter;
  dw_attr_ref at_virtuality;
  dw_attr_ref at_visibility;
  dw_attr_ref at_vtable_elem_location;
};

/* Collect the attributes that we will want to use for the checksum.  */

static void
collect_checksum_attributes (struct checksum_attributes *attrs, dw_die_ref die)
{
  dw_attr_ref a;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      switch (a->dw_attr)
        {
        case DW_AT_name:
          attrs->at_name = a;
          break;
        case DW_AT_type:
          attrs->at_type = a;
          break;
        case DW_AT_friend:
          attrs->at_friend = a;
          break;
        case DW_AT_accessibility:
          attrs->at_accessibility = a;
          break;
        case DW_AT_address_class:
          attrs->at_address_class = a;
          break;
        case DW_AT_allocated:
          attrs->at_allocated = a;
          break;
        case DW_AT_artificial:
          attrs->at_artificial = a;
          break;
        case DW_AT_associated:
          attrs->at_associated = a;
          break;
        case DW_AT_binary_scale:
          attrs->at_binary_scale = a;
          break;
        case DW_AT_bit_offset:
          attrs->at_bit_offset = a;
          break;
        case DW_AT_bit_size:
          attrs->at_bit_size = a;
          break;
        case DW_AT_bit_stride:
          attrs->at_bit_stride = a;
          break;
        case DW_AT_byte_size:
          attrs->at_byte_size = a;
          break;
        case DW_AT_byte_stride:
          attrs->at_byte_stride = a;
          break;
        case DW_AT_const_value:
          attrs->at_const_value = a;
          break;
        case DW_AT_containing_type:
          attrs->at_containing_type = a;
          break;
        case DW_AT_count:
          attrs->at_count = a;
          break;
        case DW_AT_data_location:
          attrs->at_data_location = a;
          break;
        case DW_AT_data_member_location:
          attrs->at_data_member_location = a;
          break;
        case DW_AT_decimal_scale:
          attrs->at_decimal_scale = a;
          break;
        case DW_AT_decimal_sign:
          attrs->at_decimal_sign = a;
          break;
        case DW_AT_default_value:
          attrs->at_default_value = a;
          break;
        case DW_AT_digit_count:
          attrs->at_digit_count = a;
          break;
        case DW_AT_discr:
          attrs->at_discr = a;
          break;
        case DW_AT_discr_list:
          attrs->at_discr_list = a;
          break;
        case DW_AT_discr_value:
          attrs->at_discr_value = a;
          break;
        case DW_AT_encoding:
          attrs->at_encoding = a;
          break;
        case DW_AT_endianity:
          attrs->at_endianity = a;
          break;
        case DW_AT_explicit:
          attrs->at_explicit = a;
          break;
        case DW_AT_is_optional:
          attrs->at_is_optional = a;
          break;
        case DW_AT_location:
          attrs->at_location = a;
          break;
        case DW_AT_lower_bound:
          attrs->at_lower_bound = a;
          break;
        case DW_AT_mutable:
          attrs->at_mutable = a;
          break;
        case DW_AT_ordering:
          attrs->at_ordering = a;
          break;
        case DW_AT_picture_string:
          attrs->at_picture_string = a;
          break;
        case DW_AT_prototyped:
          attrs->at_prototyped = a;
          break;
        case DW_AT_small:
          attrs->at_small = a;
          break;
        case DW_AT_segment:
          attrs->at_segment = a;
          break;
        case DW_AT_string_length:
          attrs->at_string_length = a;
          break;
        case DW_AT_threads_scaled:
          attrs->at_threads_scaled = a;
          break;
        case DW_AT_upper_bound:
          attrs->at_upper_bound = a;
          break;
        case DW_AT_use_location:
          attrs->at_use_location = a;
          break;
        case DW_AT_use_UTF8:
          attrs->at_use_UTF8 = a;
          break;
        case DW_AT_variable_parameter:
          attrs->at_variable_parameter = a;
          break;
        case DW_AT_virtuality:
          attrs->at_virtuality = a;
          break;
        case DW_AT_visibility:
          attrs->at_visibility = a;
          break;
        case DW_AT_vtable_elem_location:
          attrs->at_vtable_elem_location = a;
          break;
        default:
          break;
        }
    }
}

/* Calculate the checksum of a DIE, using an ordered subset of attributes.  */

static void
die_checksum_ordered (dw_die_ref die, struct md5_ctx *ctx, int *mark)
{
  dw_die_ref c;
  dw_die_ref decl;
  struct checksum_attributes attrs;

  CHECKSUM_ULEB128 ('D');
  CHECKSUM_ULEB128 (die->die_tag);

  memset (&attrs, 0, sizeof (attrs));

  decl = get_AT_ref (die, DW_AT_specification);
  if (decl != NULL)
    collect_checksum_attributes (&attrs, decl);
  collect_checksum_attributes (&attrs, die);

  CHECKSUM_ATTR (attrs.at_name);
  CHECKSUM_ATTR (attrs.at_accessibility);
  CHECKSUM_ATTR (attrs.at_address_class);
  CHECKSUM_ATTR (attrs.at_allocated);
  CHECKSUM_ATTR (attrs.at_artificial);
  CHECKSUM_ATTR (attrs.at_associated);
  CHECKSUM_ATTR (attrs.at_binary_scale);
  CHECKSUM_ATTR (attrs.at_bit_offset);
  CHECKSUM_ATTR (attrs.at_bit_size);
  CHECKSUM_ATTR (attrs.at_bit_stride);
  CHECKSUM_ATTR (attrs.at_byte_size);
  CHECKSUM_ATTR (attrs.at_byte_stride);
  CHECKSUM_ATTR (attrs.at_const_value);
  CHECKSUM_ATTR (attrs.at_containing_type);
  CHECKSUM_ATTR (attrs.at_count);
  CHECKSUM_ATTR (attrs.at_data_location);
  CHECKSUM_ATTR (attrs.at_data_member_location);
  CHECKSUM_ATTR (attrs.at_decimal_scale);
  CHECKSUM_ATTR (attrs.at_decimal_sign);
  CHECKSUM_ATTR (attrs.at_default_value);
  CHECKSUM_ATTR (attrs.at_digit_count);
  CHECKSUM_ATTR (attrs.at_discr);
  CHECKSUM_ATTR (attrs.at_discr_list);
  CHECKSUM_ATTR (attrs.at_discr_value);
  CHECKSUM_ATTR (attrs.at_encoding);
  CHECKSUM_ATTR (attrs.at_endianity);
  CHECKSUM_ATTR (attrs.at_explicit);
  CHECKSUM_ATTR (attrs.at_is_optional);
  CHECKSUM_ATTR (attrs.at_location);
  CHECKSUM_ATTR (attrs.at_lower_bound);
  CHECKSUM_ATTR (attrs.at_mutable);
  CHECKSUM_ATTR (attrs.at_ordering);
  CHECKSUM_ATTR (attrs.at_picture_string);
  CHECKSUM_ATTR (attrs.at_prototyped);
  CHECKSUM_ATTR (attrs.at_small);
  CHECKSUM_ATTR (attrs.at_segment);
  CHECKSUM_ATTR (attrs.at_string_length);
  CHECKSUM_ATTR (attrs.at_threads_scaled);
  CHECKSUM_ATTR (attrs.at_upper_bound);
  CHECKSUM_ATTR (attrs.at_use_location);
  CHECKSUM_ATTR (attrs.at_use_UTF8);
  CHECKSUM_ATTR (attrs.at_variable_parameter);
  CHECKSUM_ATTR (attrs.at_virtuality);
  CHECKSUM_ATTR (attrs.at_visibility);
  CHECKSUM_ATTR (attrs.at_vtable_elem_location);
  CHECKSUM_ATTR (attrs.at_type);
  CHECKSUM_ATTR (attrs.at_friend);

  /* Checksum the child DIEs, except for nested types and member functions.  */
  c = die->die_child;
  if (c) do {
    dw_attr_ref name_attr;

    c = c->die_sib;
    name_attr = get_AT (c, DW_AT_name);
    if ((is_type_die (c) || c->die_tag == DW_TAG_subprogram)
        && name_attr != NULL)
      {
        CHECKSUM_ULEB128 ('S');
        CHECKSUM_ULEB128 (c->die_tag);
        CHECKSUM_STRING (AT_string (name_attr));
      }
    else
      {
        /* Mark this DIE so it gets processed when unmarking.  */
        if (c->die_mark == 0)
          c->die_mark = -1;
        die_checksum_ordered (c, ctx, mark);
      }
  } while (c != die->die_child);

  CHECKSUM_ULEB128 (0);
}

#undef CHECKSUM
#undef CHECKSUM_STRING
#undef CHECKSUM_ATTR
#undef CHECKSUM_LEB128
#undef CHECKSUM_ULEB128

/* Generate the type signature for DIE.  This is computed by generating an
   MD5 checksum over the DIE's tag, its relevant attributes, and its
   children.  Attributes that are references to other DIEs are processed
   by recursion, using the MARK field to prevent infinite recursion.
   If the DIE is nested inside a namespace or another type, we also
   need to include that context in the signature.  The lower 64 bits
   of the resulting MD5 checksum comprise the signature.  */

static void
generate_type_signature (dw_die_ref die, comdat_type_node *type_node)
{
  int mark;
  const char *name;
  unsigned char checksum[16];
  struct md5_ctx ctx;
  dw_die_ref decl;

  name = get_AT_string (die, DW_AT_name);
  decl = get_AT_ref (die, DW_AT_specification);

  /* First, compute a signature for just the type name (and its surrounding
     context, if any.  This is stored in the type unit DIE for link-time
     ODR (one-definition rule) checking.  */

  if (is_cxx() && name != NULL)
    {
      md5_init_ctx (&ctx);

      /* Checksum the names of surrounding namespaces and structures.  */
      if (decl != NULL && decl->die_parent != NULL)
        checksum_die_context (decl->die_parent, &ctx);

      md5_process_bytes (&die->die_tag, sizeof (die->die_tag), &ctx);
      md5_process_bytes (name, strlen (name) + 1, &ctx);
      md5_finish_ctx (&ctx, checksum);

      add_AT_data8 (type_node->root_die, DW_AT_GNU_odr_signature, &checksum[8]);
    }

  /* Next, compute the complete type signature.  */

  md5_init_ctx (&ctx);
  mark = 1;
  die->die_mark = mark;

  /* Checksum the names of surrounding namespaces and structures.  */
  if (decl != NULL && decl->die_parent != NULL)
    checksum_die_context (decl->die_parent, &ctx);

  /* Checksum the DIE and its children.  */
  die_checksum_ordered (die, &ctx, &mark);
  unmark_all_dies (die);
  md5_finish_ctx (&ctx, checksum);

  /* Store the signature in the type node and link the type DIE and the
     type node together.  */
  memcpy (type_node->signature, &checksum[16 - DWARF_TYPE_SIGNATURE_SIZE],
          DWARF_TYPE_SIGNATURE_SIZE);
  die->die_id.die_type_node = type_node;
  type_node->type_die = die;

  /* If the DIE is a specification, link its declaration to the type node
     as well.  */
  if (decl != NULL)
    decl->die_id.die_type_node = type_node;
}

/* Do the location expressions look same?  */
static inline int
same_loc_p (dw_loc_descr_ref loc1, dw_loc_descr_ref loc2, int *mark)
{
  return loc1->dw_loc_opc == loc2->dw_loc_opc
         && same_dw_val_p (&loc1->dw_loc_oprnd1, &loc2->dw_loc_oprnd1, mark)
         && same_dw_val_p (&loc1->dw_loc_oprnd2, &loc2->dw_loc_oprnd2, mark);
}

/* Do the values look the same?  */
static int
same_dw_val_p (const dw_val_node *v1, const dw_val_node *v2, int *mark)
{
  dw_loc_descr_ref loc1, loc2;
  rtx r1, r2;

  if (v1->val_class != v2->val_class)
    return 0;

  switch (v1->val_class)
    {
    case dw_val_class_const:
      return v1->v.val_int == v2->v.val_int;
    case dw_val_class_unsigned_const:
      return v1->v.val_unsigned == v2->v.val_unsigned;
    case dw_val_class_const_double:
      return v1->v.val_double.high == v2->v.val_double.high
             && v1->v.val_double.low == v2->v.val_double.low;
    case dw_val_class_vec:
      if (v1->v.val_vec.length != v2->v.val_vec.length
          || v1->v.val_vec.elt_size != v2->v.val_vec.elt_size)
        return 0;
      if (memcmp (v1->v.val_vec.array, v2->v.val_vec.array,
                  v1->v.val_vec.length * v1->v.val_vec.elt_size))
        return 0;
      return 1;
    case dw_val_class_flag:
      return v1->v.val_flag == v2->v.val_flag;
    case dw_val_class_str:
      return !strcmp(v1->v.val_str->str, v2->v.val_str->str);

    case dw_val_class_addr:
      r1 = v1->v.val_addr;
      r2 = v2->v.val_addr;
      if (GET_CODE (r1) != GET_CODE (r2))
        return 0;
      return !rtx_equal_p (r1, r2);

    case dw_val_class_offset:
      return v1->v.val_offset == v2->v.val_offset;

    case dw_val_class_loc:
      for (loc1 = v1->v.val_loc, loc2 = v2->v.val_loc;
           loc1 && loc2;
           loc1 = loc1->dw_loc_next, loc2 = loc2->dw_loc_next)
        if (!same_loc_p (loc1, loc2, mark))
          return 0;
      return !loc1 && !loc2;

    case dw_val_class_die_ref:
      return same_die_p (v1->v.val_die_ref.die, v2->v.val_die_ref.die, mark);

    case dw_val_class_fde_ref:
    case dw_val_class_vms_delta:
    case dw_val_class_lbl_id:
    case dw_val_class_lineptr:
    case dw_val_class_macptr:
      return 1;

    case dw_val_class_file:
      return v1->v.val_file == v2->v.val_file;

    case dw_val_class_data8:
      return !memcmp (v1->v.val_data8, v2->v.val_data8, 8);

    default:
      return 1;
    }
}

/* Do the attributes look the same?  */

static int
same_attr_p (dw_attr_ref at1, dw_attr_ref at2, int *mark)
{
  if (at1->dw_attr != at2->dw_attr)
    return 0;

  /* We don't care that this was compiled with a different compiler
     snapshot; if the output is the same, that's what matters. */
  if (at1->dw_attr == DW_AT_producer)
    return 1;

  return same_dw_val_p (&at1->dw_attr_val, &at2->dw_attr_val, mark);
}

/* Do the dies look the same?  */

static int
same_die_p (dw_die_ref die1, dw_die_ref die2, int *mark)
{
  dw_die_ref c1, c2;
  dw_attr_ref a1;
  unsigned ix;

  /* To avoid infinite recursion.  */
  if (die1->die_mark)
    return die1->die_mark == die2->die_mark;
  die1->die_mark = die2->die_mark = ++(*mark);

  if (die1->die_tag != die2->die_tag)
    return 0;

  if (VEC_length (dw_attr_node, die1->die_attr)
      != VEC_length (dw_attr_node, die2->die_attr))
    return 0;

  FOR_EACH_VEC_ELT (dw_attr_node, die1->die_attr, ix, a1)
    if (!same_attr_p (a1, VEC_index (dw_attr_node, die2->die_attr, ix), mark))
      return 0;

  c1 = die1->die_child;
  c2 = die2->die_child;
  if (! c1)
    {
      if (c2)
        return 0;
    }
  else
    for (;;)
      {
        if (!same_die_p (c1, c2, mark))
          return 0;
        c1 = c1->die_sib;
        c2 = c2->die_sib;
        if (c1 == die1->die_child)
          {
            if (c2 == die2->die_child)
              break;
            else
              return 0;
          }
    }

  return 1;
}

/* Do the dies look the same?  Wrapper around same_die_p.  */

static int
same_die_p_wrap (dw_die_ref die1, dw_die_ref die2)
{
  int mark = 0;
  int ret = same_die_p (die1, die2, &mark);

  unmark_all_dies (die1);
  unmark_all_dies (die2);

  return ret;
}

/* The prefix to attach to symbols on DIEs in the current comdat debug
   info section.  */
static char *comdat_symbol_id;

/* The index of the current symbol within the current comdat CU.  */
static unsigned int comdat_symbol_number;

/* Calculate the MD5 checksum of the compilation unit DIE UNIT_DIE and its
   children, and set comdat_symbol_id accordingly.  */

static void
compute_section_prefix (dw_die_ref unit_die)
{
  const char *die_name = get_AT_string (unit_die, DW_AT_name);
  const char *base = die_name ? lbasename (die_name) : "anonymous";
  char *name = XALLOCAVEC (char, strlen (base) + 64);
  char *p;
  int i, mark;
  unsigned char checksum[16];
  struct md5_ctx ctx;

  /* Compute the checksum of the DIE, then append part of it as hex digits to
     the name filename of the unit.  */

  md5_init_ctx (&ctx);
  mark = 0;
  die_checksum (unit_die, &ctx, &mark);
  unmark_all_dies (unit_die);
  md5_finish_ctx (&ctx, checksum);

  sprintf (name, "%s.", base);
  clean_symbol_name (name);

  p = name + strlen (name);
  for (i = 0; i < 4; i++)
    {
      sprintf (p, "%.2x", checksum[i]);
      p += 2;
    }

  comdat_symbol_id = unit_die->die_id.die_symbol = xstrdup (name);
  comdat_symbol_number = 0;
}

/* Returns nonzero if DIE represents a type, in the sense of TYPE_P.  */

static int
is_type_die (dw_die_ref die)
{
  switch (die->die_tag)
    {
    case DW_TAG_array_type:
    case DW_TAG_class_type:
    case DW_TAG_interface_type:
    case DW_TAG_enumeration_type:
    case DW_TAG_pointer_type:
    case DW_TAG_reference_type:
    case DW_TAG_rvalue_reference_type:
    case DW_TAG_string_type:
    case DW_TAG_structure_type:
    case DW_TAG_subroutine_type:
    case DW_TAG_union_type:
    case DW_TAG_ptr_to_member_type:
    case DW_TAG_set_type:
    case DW_TAG_subrange_type:
    case DW_TAG_base_type:
    case DW_TAG_const_type:
    case DW_TAG_file_type:
    case DW_TAG_packed_type:
    case DW_TAG_volatile_type:
    case DW_TAG_typedef:
      return 1;
    default:
      return 0;
    }
}

/* Returns 1 iff C is the sort of DIE that should go into a COMDAT CU.
   Basically, we want to choose the bits that are likely to be shared between
   compilations (types) and leave out the bits that are specific to individual
   compilations (functions).  */

static int
is_comdat_die (dw_die_ref c)
{
  /* I think we want to leave base types and __vtbl_ptr_type in the main CU, as
     we do for stabs.  The advantage is a greater likelihood of sharing between
     objects that don't include headers in the same order (and therefore would
     put the base types in a different comdat).  jason 8/28/00 */

  if (c->die_tag == DW_TAG_base_type)
    return 0;

  if (c->die_tag == DW_TAG_pointer_type
      || c->die_tag == DW_TAG_reference_type
      || c->die_tag == DW_TAG_rvalue_reference_type
      || c->die_tag == DW_TAG_const_type
      || c->die_tag == DW_TAG_volatile_type)
    {
      dw_die_ref t = get_AT_ref (c, DW_AT_type);

      return t ? is_comdat_die (t) : 0;
    }

  return is_type_die (c);
}

/* Returns 1 iff C is the sort of DIE that might be referred to from another
   compilation unit.  */

static int
is_symbol_die (dw_die_ref c)
{
  return (is_type_die (c)
          || is_declaration_die (c)
          || c->die_tag == DW_TAG_namespace
          || c->die_tag == DW_TAG_module);
}

/* Returns true iff C is a compile-unit DIE.  */

static inline bool
is_cu_die (dw_die_ref c)
{
  return c && c->die_tag == DW_TAG_compile_unit;
}

static char *
gen_internal_sym (const char *prefix)
{
  char buf[256];

  ASM_GENERATE_INTERNAL_LABEL (buf, prefix, label_num++);
  return xstrdup (buf);
}

/* Assign symbols to all worthy DIEs under DIE.  */

static void
assign_symbol_names (dw_die_ref die)
{
  dw_die_ref c;

  if (is_symbol_die (die))
    {
      if (comdat_symbol_id)
        {
          char *p = XALLOCAVEC (char, strlen (comdat_symbol_id) + 64);

          sprintf (p, "%s.%s.%x", DIE_LABEL_PREFIX,
                   comdat_symbol_id, comdat_symbol_number++);
          die->die_id.die_symbol = xstrdup (p);
        }
      else
        die->die_id.die_symbol = gen_internal_sym ("LDIE");
    }

  FOR_EACH_CHILD (die, c, assign_symbol_names (c));
}

struct cu_hash_table_entry
{
  dw_die_ref cu;
  unsigned min_comdat_num, max_comdat_num;
  struct cu_hash_table_entry *next;
};

/* Routines to manipulate hash table of CUs.  */
static hashval_t
htab_cu_hash (const void *of)
{
  const struct cu_hash_table_entry *const entry =
    (const struct cu_hash_table_entry *) of;

  return htab_hash_string (entry->cu->die_id.die_symbol);
}

static int
htab_cu_eq (const void *of1, const void *of2)
{
  const struct cu_hash_table_entry *const entry1 =
    (const struct cu_hash_table_entry *) of1;
  const struct die_struct *const entry2 = (const struct die_struct *) of2;

  return !strcmp (entry1->cu->die_id.die_symbol, entry2->die_id.die_symbol);
}

static void
htab_cu_del (void *what)
{
  struct cu_hash_table_entry *next,
    *entry = (struct cu_hash_table_entry *) what;

  while (entry)
    {
      next = entry->next;
      free (entry);
      entry = next;
    }
}

/* Check whether we have already seen this CU and set up SYM_NUM
   accordingly.  */
static int
check_duplicate_cu (dw_die_ref cu, htab_t htable, unsigned int *sym_num)
{
  struct cu_hash_table_entry dummy;
  struct cu_hash_table_entry **slot, *entry, *last = &dummy;

  dummy.max_comdat_num = 0;

  slot = (struct cu_hash_table_entry **)
    htab_find_slot_with_hash (htable, cu, htab_hash_string (cu->die_id.die_symbol),
        INSERT);
  entry = *slot;

  for (; entry; last = entry, entry = entry->next)
    {
      if (same_die_p_wrap (cu, entry->cu))
        break;
    }

  if (entry)
    {
      *sym_num = entry->min_comdat_num;
      return 1;
    }

  entry = XCNEW (struct cu_hash_table_entry);
  entry->cu = cu;
  entry->min_comdat_num = *sym_num = last->max_comdat_num;
  entry->next = *slot;
  *slot = entry;

  return 0;
}

/* Record SYM_NUM to record of CU in HTABLE.  */
static void
record_comdat_symbol_number (dw_die_ref cu, htab_t htable, unsigned int sym_num)
{
  struct cu_hash_table_entry **slot, *entry;

  slot = (struct cu_hash_table_entry **)
    htab_find_slot_with_hash (htable, cu, htab_hash_string (cu->die_id.die_symbol),
        NO_INSERT);
  entry = *slot;

  entry->max_comdat_num = sym_num;
}

/* Traverse the DIE (which is always comp_unit_die), and set up
   additional compilation units for each of the include files we see
   bracketed by BINCL/EINCL.  */

static void
break_out_includes (dw_die_ref die)
{
  dw_die_ref c;
  dw_die_ref unit = NULL;
  limbo_die_node *node, **pnode;
  htab_t cu_hash_table;

  c = die->die_child;
  if (c) do {
    dw_die_ref prev = c;
    c = c->die_sib;
    while (c->die_tag == DW_TAG_GNU_BINCL || c->die_tag == DW_TAG_GNU_EINCL
           || (unit && is_comdat_die (c)))
      {
        dw_die_ref next = c->die_sib;

        /* This DIE is for a secondary CU; remove it from the main one.  */
        remove_child_with_prev (c, prev);

        if (c->die_tag == DW_TAG_GNU_BINCL)
          unit = push_new_compile_unit (unit, c);
        else if (c->die_tag == DW_TAG_GNU_EINCL)
          unit = pop_compile_unit (unit);
        else
          add_child_die (unit, c);
        c = next;
        if (c == die->die_child)
          break;
      }
  } while (c != die->die_child);

#if 0
  /* We can only use this in debugging, since the frontend doesn't check
     to make sure that we leave every include file we enter.  */
  gcc_assert (!unit);
#endif

  assign_symbol_names (die);
  cu_hash_table = htab_create (10, htab_cu_hash, htab_cu_eq, htab_cu_del);
  for (node = limbo_die_list, pnode = &limbo_die_list;
       node;
       node = node->next)
    {
      int is_dupl;

      compute_section_prefix (node->die);
      is_dupl = check_duplicate_cu (node->die, cu_hash_table,
                        &comdat_symbol_number);
      assign_symbol_names (node->die);
      if (is_dupl)
        *pnode = node->next;
      else
        {
          pnode = &node->next;
          record_comdat_symbol_number (node->die, cu_hash_table,
                comdat_symbol_number);
        }
    }
  htab_delete (cu_hash_table);
}

/* Return non-zero if this DIE is a declaration.  */

static int
is_declaration_die (dw_die_ref die)
{
  dw_attr_ref a;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (a->dw_attr == DW_AT_declaration)
      return 1;

  return 0;
}

/* Return non-zero if this DIE is nested inside a subprogram.  */

static int
is_nested_in_subprogram (dw_die_ref die)
{
  dw_die_ref decl = get_AT_ref (die, DW_AT_specification);

  if (decl == NULL)
    decl = die;
  return local_scope_p (decl);
}

/* Return non-zero if this is a type DIE that should be moved to a
   COMDAT .debug_types section.  */

static int
should_move_die_to_comdat (dw_die_ref die)
{
  switch (die->die_tag)
    {
    case DW_TAG_class_type:
    case DW_TAG_structure_type:
    case DW_TAG_enumeration_type:
    case DW_TAG_union_type:
      /* Don't move declarations, inlined instances, or types nested in a
         subprogram.  */
      if (is_declaration_die (die)
          || get_AT (die, DW_AT_abstract_origin)
          || is_nested_in_subprogram (die))
        return 0;
      return 1;
    case DW_TAG_array_type:
    case DW_TAG_interface_type:
    case DW_TAG_pointer_type:
    case DW_TAG_reference_type:
    case DW_TAG_rvalue_reference_type:
    case DW_TAG_string_type:
    case DW_TAG_subroutine_type:
    case DW_TAG_ptr_to_member_type:
    case DW_TAG_set_type:
    case DW_TAG_subrange_type:
    case DW_TAG_base_type:
    case DW_TAG_const_type:
    case DW_TAG_file_type:
    case DW_TAG_packed_type:
    case DW_TAG_volatile_type:
    case DW_TAG_typedef:
    default:
      return 0;
    }
}

/* Make a clone of DIE.  */

static dw_die_ref
clone_die (dw_die_ref die)
{
  dw_die_ref clone;
  dw_attr_ref a;
  unsigned ix;

  clone = ggc_alloc_cleared_die_node ();
  clone->die_tag = die->die_tag;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    add_dwarf_attr (clone, a);

  return clone;
}

/* Make a clone of the tree rooted at DIE.  */

static dw_die_ref
clone_tree (dw_die_ref die)
{
  dw_die_ref c;
  dw_die_ref clone = clone_die (die);

  FOR_EACH_CHILD (die, c, add_child_die (clone, clone_tree(c)));

  return clone;
}

/* Make a clone of DIE as a declaration.  */

static dw_die_ref
clone_as_declaration (dw_die_ref die)
{
  dw_die_ref clone;
  dw_die_ref decl;
  dw_attr_ref a;
  unsigned ix;

  /* If the DIE is already a declaration, just clone it.  */
  if (is_declaration_die (die))
    return clone_die (die);

  /* If the DIE is a specification, just clone its declaration DIE.  */
  decl = get_AT_ref (die, DW_AT_specification);
  if (decl != NULL)
    return clone_die (decl);

  clone = ggc_alloc_cleared_die_node ();
  clone->die_tag = die->die_tag;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      /* We don't want to copy over all attributes.
         For example we don't want DW_AT_byte_size because otherwise we will no
         longer have a declaration and GDB will treat it as a definition.  */

      switch (a->dw_attr)
        {
        case DW_AT_artificial:
        case DW_AT_containing_type:
        case DW_AT_external:
        case DW_AT_name:
        case DW_AT_type:
        case DW_AT_virtuality:
        case DW_AT_linkage_name:
        case DW_AT_MIPS_linkage_name:
          add_dwarf_attr (clone, a);
          break;
        case DW_AT_byte_size:
        default:
          break;
        }
    }

  if (die->die_id.die_type_node)
    add_AT_die_ref (clone, DW_AT_signature, die);

  add_AT_flag (clone, DW_AT_declaration, 1);
  return clone;
}

/* Copy the declaration context to the new compile unit DIE.  This includes
   any surrounding namespace or type declarations.  If the DIE has an
   AT_specification attribute, it also includes attributes and children
   attached to the specification.  */

static void
copy_declaration_context (dw_die_ref unit, dw_die_ref die)
{
  dw_die_ref decl;
  dw_die_ref new_decl;

  decl = get_AT_ref (die, DW_AT_specification);
  if (decl == NULL)
    decl = die;
  else
    {
      unsigned ix;
      dw_die_ref c;
      dw_attr_ref a;

      /* Copy the type node pointer from the new DIE to the original
         declaration DIE so we can forward references later.  */
      decl->die_id.die_type_node = die->die_id.die_type_node;

      remove_AT (die, DW_AT_specification);

      FOR_EACH_VEC_ELT (dw_attr_node, decl->die_attr, ix, a)
        {
          if (a->dw_attr != DW_AT_name
              && a->dw_attr != DW_AT_declaration
              && a->dw_attr != DW_AT_external)
            add_dwarf_attr (die, a);
        }

      FOR_EACH_CHILD (decl, c, add_child_die (die, clone_tree(c)));
    }

  if (decl->die_parent != NULL
      && decl->die_parent->die_tag != DW_TAG_compile_unit
      && decl->die_parent->die_tag != DW_TAG_type_unit)
    {
      new_decl = copy_ancestor_tree (unit, decl, NULL);
      if (new_decl != NULL)
        {
          remove_AT (new_decl, DW_AT_signature);
          add_AT_specification (die, new_decl);
        }
    }
}

/* Generate the skeleton ancestor tree for the given NODE, then clone
   the DIE and add the clone into the tree.  */

static void
generate_skeleton_ancestor_tree (skeleton_chain_node *node)
{
  if (node->new_die != NULL)
    return;

  node->new_die = clone_as_declaration (node->old_die);

  if (node->parent != NULL)
    {
      generate_skeleton_ancestor_tree (node->parent);
      add_child_die (node->parent->new_die, node->new_die);
    }
}

/* Generate a skeleton tree of DIEs containing any declarations that are
   found in the original tree.  We traverse the tree looking for declaration
   DIEs, and construct the skeleton from the bottom up whenever we find one.  */

static void
generate_skeleton_bottom_up (skeleton_chain_node *parent)
{
  skeleton_chain_node node;
  dw_die_ref c;
  dw_die_ref first;
  dw_die_ref prev = NULL;
  dw_die_ref next = NULL;

  node.parent = parent;

  first = c = parent->old_die->die_child;
  if (c)
    next = c->die_sib;
  if (c) do {
    if (prev == NULL || prev->die_sib == c)
      prev = c;
    c = next;
    next = (c == first ? NULL : c->die_sib);
    node.old_die = c;
    node.new_die = NULL;
    if (is_declaration_die (c))
      {
        /* Clone the existing DIE, move the original to the skeleton
           tree (which is in the main CU), and put the clone, with
           all the original's children, where the original came from.  */
        dw_die_ref clone = clone_die (c);
        move_all_children (c, clone);

        replace_child (c, clone, prev);
        generate_skeleton_ancestor_tree (parent);
        add_child_die (parent->new_die, c);
        node.new_die = c;
        c = clone;
      }
    generate_skeleton_bottom_up (&node);
  } while (next != NULL);
}

/* Wrapper function for generate_skeleton_bottom_up.  */

static dw_die_ref
generate_skeleton (dw_die_ref die)
{
  skeleton_chain_node node;

  node.old_die = die;
  node.new_die = NULL;
  node.parent = NULL;

  /* If this type definition is nested inside another type,
     always leave at least a declaration in its place.  */
  if (die->die_parent != NULL && is_type_die (die->die_parent))
    node.new_die = clone_as_declaration (die);

  generate_skeleton_bottom_up (&node);
  return node.new_die;
}

/* Remove the DIE from its parent, possibly replacing it with a cloned
   declaration.  The original DIE will be moved to a new compile unit
   so that existing references to it follow it to the new location.  If
   any of the original DIE's descendants is a declaration, we need to
   replace the original DIE with a skeleton tree and move the
   declarations back into the skeleton tree.  */

static dw_die_ref
remove_child_or_replace_with_skeleton (dw_die_ref child, dw_die_ref prev)
{
  dw_die_ref skeleton;

  skeleton = generate_skeleton (child);
  if (skeleton == NULL)
    remove_child_with_prev (child, prev);
  else
    {
      skeleton->die_id.die_type_node = child->die_id.die_type_node;
      replace_child (child, skeleton, prev);
    }

  return skeleton;
}

/* Traverse the DIE and set up additional .debug_types sections for each
   type worthy of being placed in a COMDAT section.  */

static void
break_out_comdat_types (dw_die_ref die)
{
  dw_die_ref c;
  dw_die_ref first;
  dw_die_ref prev = NULL;
  dw_die_ref next = NULL;
  dw_die_ref unit = NULL;

  first = c = die->die_child;
  if (c)
    next = c->die_sib;
  if (c) do {
    if (prev == NULL || prev->die_sib == c)
      prev = c;
    c = next;
    next = (c == first ? NULL : c->die_sib);
    if (should_move_die_to_comdat (c))
      {
        dw_die_ref replacement;
        comdat_type_node_ref type_node;

        /* Create a new type unit DIE as the root for the new tree, and
           add it to the list of comdat types.  */
        unit = new_die (DW_TAG_type_unit, NULL, NULL);
        add_AT_unsigned (unit, DW_AT_language,
                         get_AT_unsigned (comp_unit_die (), DW_AT_language));
        type_node = ggc_alloc_cleared_comdat_type_node ();
        type_node->root_die = unit;
        type_node->next = comdat_type_list;
        comdat_type_list = type_node;

        /* Generate the type signature.  */
        generate_type_signature (c, type_node);

        /* Copy the declaration context, attributes, and children of the
           declaration into the new compile unit DIE.  */
        copy_declaration_context (unit, c);

        /* Remove this DIE from the main CU.  */
        replacement = remove_child_or_replace_with_skeleton (c, prev);

        /* Break out nested types into their own type units.  */
        break_out_comdat_types (c);

        /* Add the DIE to the new compunit.  */
        add_child_die (unit, c);

        if (replacement != NULL)
          c = replacement;
      }
    else if (c->die_tag == DW_TAG_namespace
             || c->die_tag == DW_TAG_class_type
             || c->die_tag == DW_TAG_structure_type
             || c->die_tag == DW_TAG_union_type)
      {
        /* Look for nested types that can be broken out.  */
        break_out_comdat_types (c);
      }
  } while (next != NULL);
}

/* Structure to map a DIE in one CU to its copy in a comdat type unit.  */

struct decl_table_entry
{
  dw_die_ref orig;
  dw_die_ref copy;
};

/* Routines to manipulate hash table of copied declarations.  */

static hashval_t
htab_decl_hash (const void *of)
{
  const struct decl_table_entry *const entry =
    (const struct decl_table_entry *) of;

  return htab_hash_pointer (entry->orig);
}

static int
htab_decl_eq (const void *of1, const void *of2)
{
  const struct decl_table_entry *const entry1 =
    (const struct decl_table_entry *) of1;
  const struct die_struct *const entry2 = (const struct die_struct *) of2;

  return entry1->orig == entry2;
}

static void
htab_decl_del (void *what)
{
  struct decl_table_entry *entry = (struct decl_table_entry *) what;

  free (entry);
}

/* Copy DIE and its ancestors, up to, but not including, the compile unit
   or type unit entry, to a new tree.  Adds the new tree to UNIT and returns
   a pointer to the copy of DIE.  If DECL_TABLE is provided, it is used
   to check if the ancestor has already been copied into UNIT.  */

static dw_die_ref
copy_ancestor_tree (dw_die_ref unit, dw_die_ref die, htab_t decl_table)
{
  dw_die_ref parent = die->die_parent;
  dw_die_ref new_parent = unit;
  dw_die_ref copy;
  void **slot = NULL;
  struct decl_table_entry *entry = NULL;

  if (decl_table)
    {
      /* Check if the entry has already been copied to UNIT.  */
      slot = htab_find_slot_with_hash (decl_table, die,
                                       htab_hash_pointer (die), INSERT);
      if (*slot != HTAB_EMPTY_ENTRY)
        {
          entry = (struct decl_table_entry *) *slot;
          return entry->copy;
        }

      /* Record in DECL_TABLE that DIE has been copied to UNIT.  */
      entry = XCNEW (struct decl_table_entry);
      entry->orig = die;
      entry->copy = NULL;
      *slot = entry;
    }

  if (parent != NULL)
    {
      dw_die_ref spec = get_AT_ref (parent, DW_AT_specification);
      if (spec != NULL)
        parent = spec;
      if (parent->die_tag != DW_TAG_compile_unit
          && parent->die_tag != DW_TAG_type_unit)
        new_parent = copy_ancestor_tree (unit, parent, decl_table);
    }

  copy = clone_as_declaration (die);
  add_child_die (new_parent, copy);

  if (decl_table != NULL)
    {
      /* Record the pointer to the copy.  */
      entry->copy = copy;
    }

  return copy;
}

/* Walk the DIE and its children, looking for references to incomplete
   or trivial types that are unmarked (i.e., that are not in the current
   type_unit).  */

static void
copy_decls_walk (dw_die_ref unit, dw_die_ref die, htab_t decl_table)
{
  dw_die_ref c;
  dw_attr_ref a;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      if (AT_class (a) == dw_val_class_die_ref)
        {
          dw_die_ref targ = AT_ref (a);
          comdat_type_node_ref type_node = targ->die_id.die_type_node;
          void **slot;
          struct decl_table_entry *entry;

          if (targ->die_mark != 0 || type_node != NULL)
            continue;

          slot = htab_find_slot_with_hash (decl_table, targ,
                                           htab_hash_pointer (targ), INSERT);

          if (*slot != HTAB_EMPTY_ENTRY)
            {
              /* TARG has already been copied, so we just need to
                 modify the reference to point to the copy.  */
              entry = (struct decl_table_entry *) *slot;
              a->dw_attr_val.v.val_die_ref.die = entry->copy;
            }
          else
            {
              dw_die_ref parent = unit;
              dw_die_ref copy = clone_tree (targ);

              /* Make sure the cloned tree is marked as part of the
                 type unit.  */
              mark_dies (copy);

              /* Record in DECL_TABLE that TARG has been copied.
                 Need to do this now, before the recursive call,
                 because DECL_TABLE may be expanded and SLOT
                 would no longer be a valid pointer.  */
              entry = XCNEW (struct decl_table_entry);
              entry->orig = targ;
              entry->copy = copy;
              *slot = entry;

              /* If TARG has surrounding context, copy its ancestor tree
                 into the new type unit.  */
              if (targ->die_parent != NULL
                  && targ->die_parent->die_tag != DW_TAG_compile_unit
                  && targ->die_parent->die_tag != DW_TAG_type_unit)
                parent = copy_ancestor_tree (unit, targ->die_parent,
                                             decl_table);

              add_child_die (parent, copy);
              a->dw_attr_val.v.val_die_ref.die = copy;

              /* Make sure the newly-copied DIE is walked.  If it was
                 installed in a previously-added context, it won't
                 get visited otherwise.  */
              if (parent != unit)
                {
                  /* Find the highest point of the newly-added tree,
                     mark each node along the way, and walk from there.  */
                  parent->die_mark = 1;
                  while (parent->die_parent
                         && parent->die_parent->die_mark == 0)
                    {
                      parent = parent->die_parent;
                      parent->die_mark = 1;
                    }
                  copy_decls_walk (unit, parent, decl_table);
                }
            }
        }
    }

  FOR_EACH_CHILD (die, c, copy_decls_walk (unit, c, decl_table));
}

/* Copy declarations for "unworthy" types into the new comdat section.
   Incomplete types, modified types, and certain other types aren't broken
   out into comdat sections of their own, so they don't have a signature,
   and we need to copy the declaration into the same section so that we
   don't have an external reference.  */

static void
copy_decls_for_unworthy_types (dw_die_ref unit)
{
  htab_t decl_table;

  mark_dies (unit);
  decl_table = htab_create (10, htab_decl_hash, htab_decl_eq, htab_decl_del);
  copy_decls_walk (unit, unit, decl_table);
  htab_delete (decl_table);
  unmark_dies (unit);
}

/* Traverse the DIE and add a sibling attribute if it may have the
   effect of speeding up access to siblings.  To save some space,
   avoid generating sibling attributes for DIE's without children.  */

static void
add_sibling_attributes (dw_die_ref die)
{
  dw_die_ref c;

  if (! die->die_child)
    return;

  if (die->die_parent && die != die->die_parent->die_child)
    add_AT_die_ref (die, DW_AT_sibling, die->die_sib);

  FOR_EACH_CHILD (die, c, add_sibling_attributes (c));
}

/* Output all location lists for the DIE and its children.  */

static void
output_location_lists (dw_die_ref die)
{
  dw_die_ref c;
  dw_attr_ref a;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (AT_class (a) == dw_val_class_loc_list)
      output_loc_list (AT_loc_list (a));

  FOR_EACH_CHILD (die, c, output_location_lists (c));
}

/* The format of each DIE (and its attribute value pairs) is encoded in an
   abbreviation table.  This routine builds the abbreviation table and assigns
   a unique abbreviation id for each abbreviation entry.  The children of each
   die are visited recursively.  */

static void
build_abbrev_table (dw_die_ref die)
{
  unsigned long abbrev_id;
  unsigned int n_alloc;
  dw_die_ref c;
  dw_attr_ref a;
  unsigned ix;

  /* Scan the DIE references, and mark as external any that refer to
     DIEs from other CUs (i.e. those which are not marked).  */
  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (AT_class (a) == dw_val_class_die_ref
        && AT_ref (a)->die_mark == 0)
      {
        gcc_assert (dwarf_version >= 4 || AT_ref (a)->die_id.die_symbol);
        set_AT_ref_external (a, 1);
      }

  for (abbrev_id = 1; abbrev_id < abbrev_die_table_in_use; ++abbrev_id)
    {
      dw_die_ref abbrev = abbrev_die_table[abbrev_id];
      dw_attr_ref die_a, abbrev_a;
      unsigned ix;
      bool ok = true;

      if (abbrev->die_tag != die->die_tag)
        continue;
      if ((abbrev->die_child != NULL) != (die->die_child != NULL))
        continue;

      if (VEC_length (dw_attr_node, abbrev->die_attr)
          != VEC_length (dw_attr_node, die->die_attr))
        continue;

      FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, die_a)
        {
          abbrev_a = VEC_index (dw_attr_node, abbrev->die_attr, ix);
          if ((abbrev_a->dw_attr != die_a->dw_attr)
              || (value_format (abbrev_a) != value_format (die_a)))
            {
              ok = false;
              break;
            }
        }
      if (ok)
        break;
    }

  if (abbrev_id >= abbrev_die_table_in_use)
    {
      if (abbrev_die_table_in_use >= abbrev_die_table_allocated)
        {
          n_alloc = abbrev_die_table_allocated + ABBREV_DIE_TABLE_INCREMENT;
          abbrev_die_table = GGC_RESIZEVEC (dw_die_ref, abbrev_die_table,
                                            n_alloc);

          memset (&abbrev_die_table[abbrev_die_table_allocated], 0,
                 (n_alloc - abbrev_die_table_allocated) * sizeof (dw_die_ref));
          abbrev_die_table_allocated = n_alloc;
        }

      ++abbrev_die_table_in_use;
      abbrev_die_table[abbrev_id] = die;
    }

  die->die_abbrev = abbrev_id;
  FOR_EACH_CHILD (die, c, build_abbrev_table (c));
}
\f
/* Return the power-of-two number of bytes necessary to represent VALUE.  */

static int
constant_size (unsigned HOST_WIDE_INT value)
{
  int log;

  if (value == 0)
    log = 0;
  else
    log = floor_log2 (value);

  log = log / 8;
  log = 1 << (floor_log2 (log) + 1);

  return log;
}

/* Return the size of a DIE as it is represented in the
   .debug_info section.  */

static unsigned long
size_of_die (dw_die_ref die)
{
  unsigned long size = 0;
  dw_attr_ref a;
  unsigned ix;

  size += size_of_uleb128 (die->die_abbrev);
  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      switch (AT_class (a))
        {
        case dw_val_class_addr:
          size += DWARF2_ADDR_SIZE;
          break;
        case dw_val_class_offset:
          size += DWARF_OFFSET_SIZE;
          break;
        case dw_val_class_loc:
          {
            unsigned long lsize = size_of_locs (AT_loc (a));

            /* Block length.  */
            if (dwarf_version >= 4)
              size += size_of_uleb128 (lsize);
            else
              size += constant_size (lsize);
            size += lsize;
          }
          break;
        case dw_val_class_loc_list:
          size += DWARF_OFFSET_SIZE;
          break;
        case dw_val_class_range_list:
          size += DWARF_OFFSET_SIZE;
          break;
        case dw_val_class_const:
          size += size_of_sleb128 (AT_int (a));
          break;
        case dw_val_class_unsigned_const:
          size += constant_size (AT_unsigned (a));
          break;
        case dw_val_class_const_double:
          size += 2 * HOST_BITS_PER_WIDE_INT / HOST_BITS_PER_CHAR;
          if (HOST_BITS_PER_WIDE_INT >= 64)
            size++; /* block */
          break;
        case dw_val_class_vec:
          size += constant_size (a->dw_attr_val.v.val_vec.length
                                 * a->dw_attr_val.v.val_vec.elt_size)
                  + a->dw_attr_val.v.val_vec.length
                    * a->dw_attr_val.v.val_vec.elt_size; /* block */
          break;
        case dw_val_class_flag:
          if (dwarf_version >= 4)
            /* Currently all add_AT_flag calls pass in 1 as last argument,
               so DW_FORM_flag_present can be used.  If that ever changes,
               we'll need to use DW_FORM_flag and have some optimization
               in build_abbrev_table that will change those to
               DW_FORM_flag_present if it is set to 1 in all DIEs using
               the same abbrev entry.  */
            gcc_assert (a->dw_attr_val.v.val_flag == 1);
          else
            size += 1;
          break;
        case dw_val_class_die_ref:
          if (AT_ref_external (a))
            {
              /* In DWARF4, we use DW_FORM_sig8; for earlier versions
                 we use DW_FORM_ref_addr.  In DWARF2, DW_FORM_ref_addr
                 is sized by target address length, whereas in DWARF3
                 it's always sized as an offset.  */
              if (dwarf_version >= 4)
                size += DWARF_TYPE_SIGNATURE_SIZE;
              else if (dwarf_version == 2)
                size += DWARF2_ADDR_SIZE;
              else
                size += DWARF_OFFSET_SIZE;
            }
          else
            size += DWARF_OFFSET_SIZE;
          break;
        case dw_val_class_fde_ref:
          size += DWARF_OFFSET_SIZE;
          break;
        case dw_val_class_lbl_id:
          size += DWARF2_ADDR_SIZE;
          break;
        case dw_val_class_lineptr:
        case dw_val_class_macptr:
          size += DWARF_OFFSET_SIZE;
          break;
        case dw_val_class_str:
          if (AT_string_form (a) == DW_FORM_strp)
            size += DWARF_OFFSET_SIZE;
          else
            size += strlen (a->dw_attr_val.v.val_str->str) + 1;
          break;
        case dw_val_class_file:
          size += constant_size (maybe_emit_file (a->dw_attr_val.v.val_file));
          break;
        case dw_val_class_data8:
          size += 8;
          break;
        case dw_val_class_vms_delta:
          size += DWARF_OFFSET_SIZE;
          break;
        default:
          gcc_unreachable ();
        }
    }

  return size;
}

/* Size the debugging information associated with a given DIE.  Visits the
   DIE's children recursively.  Updates the global variable next_die_offset, on
   each time through.  Uses the current value of next_die_offset to update the
   die_offset field in each DIE.  */

static void
calc_die_sizes (dw_die_ref die)
{
  dw_die_ref c;

  die->die_offset = next_die_offset;
  next_die_offset += size_of_die (die);

  FOR_EACH_CHILD (die, c, calc_die_sizes (c));

  if (die->die_child != NULL)
    /* Count the null byte used to terminate sibling lists.  */
    next_die_offset += 1;
}

/* Set the marks for a die and its children.  We do this so
   that we know whether or not a reference needs to use FORM_ref_addr; only
   DIEs in the same CU will be marked.  We used to clear out the offset
   and use that as the flag, but ran into ordering problems.  */

static void
mark_dies (dw_die_ref die)
{
  dw_die_ref c;

  gcc_assert (!die->die_mark);

  die->die_mark = 1;
  FOR_EACH_CHILD (die, c, mark_dies (c));
}

/* Clear the marks for a die and its children.  */

static void
unmark_dies (dw_die_ref die)
{
  dw_die_ref c;

  if (dwarf_version < 4)
    gcc_assert (die->die_mark);

  die->die_mark = 0;
  FOR_EACH_CHILD (die, c, unmark_dies (c));
}

/* Clear the marks for a die, its children and referred dies.  */

static void
unmark_all_dies (dw_die_ref die)
{
  dw_die_ref c;
  dw_attr_ref a;
  unsigned ix;

  if (!die->die_mark)
    return;
  die->die_mark = 0;

  FOR_EACH_CHILD (die, c, unmark_all_dies (c));

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (AT_class (a) == dw_val_class_die_ref)
      unmark_all_dies (AT_ref (a));
}

/* Return the size of the .debug_pubnames or .debug_pubtypes table
   generated for the compilation unit.  */

static unsigned long
size_of_pubnames (VEC (pubname_entry, gc) * names)
{
  unsigned long size;
  unsigned i;
  pubname_ref p;

  size = DWARF_PUBNAMES_HEADER_SIZE;
  FOR_EACH_VEC_ELT (pubname_entry, names, i, p)
    if (names != pubtype_table
        || p->die->die_offset != 0
        || !flag_eliminate_unused_debug_types)
      size += strlen (p->name) + DWARF_OFFSET_SIZE + 1;

  size += DWARF_OFFSET_SIZE;
  return size;
}

/* Return the size of the information in the .debug_aranges section.  */

static unsigned long
size_of_aranges (void)
{
  unsigned long size;

  size = DWARF_ARANGES_HEADER_SIZE;

  /* Count the address/length pair for this compilation unit.  */
  if (text_section_used)
    size += 2 * DWARF2_ADDR_SIZE;
  if (cold_text_section_used)
    size += 2 * DWARF2_ADDR_SIZE;
  size += 2 * DWARF2_ADDR_SIZE * arange_table_in_use;

  /* Count the two zero words used to terminated the address range table.  */
  size += 2 * DWARF2_ADDR_SIZE;
  return size;
}
\f
/* Select the encoding of an attribute value.  */

static enum dwarf_form
value_format (dw_attr_ref a)
{
  switch (a->dw_attr_val.val_class)
    {
    case dw_val_class_addr:
      /* Only very few attributes allow DW_FORM_addr.  */
      switch (a->dw_attr)
        {
        case DW_AT_low_pc:
        case DW_AT_high_pc:
        case DW_AT_entry_pc:
        case DW_AT_trampoline:
          return DW_FORM_addr;
        default:
          break;
        }
      switch (DWARF2_ADDR_SIZE)
        {
        case 1:
          return DW_FORM_data1;
        case 2:
          return DW_FORM_data2;
        case 4:
          return DW_FORM_data4;
        case 8:
          return DW_FORM_data8;
        default:
          gcc_unreachable ();
        }
    case dw_val_class_range_list:
    case dw_val_class_loc_list:
      if (dwarf_version >= 4)
        return DW_FORM_sec_offset;
      /* FALLTHRU */
    case dw_val_class_vms_delta:
    case dw_val_class_offset:
      switch (DWARF_OFFSET_SIZE)
        {
        case 4:
          return DW_FORM_data4;
        case 8:
          return DW_FORM_data8;
        default:
          gcc_unreachable ();
        }
    case dw_val_class_loc:
      if (dwarf_version >= 4)
        return DW_FORM_exprloc;
      switch (constant_size (size_of_locs (AT_loc (a))))
        {
        case 1:
          return DW_FORM_block1;
        case 2:
          return DW_FORM_block2;
        default:
          gcc_unreachable ();
        }
    case dw_val_class_const:
      return DW_FORM_sdata;
    case dw_val_class_unsigned_const:
      switch (constant_size (AT_unsigned (a)))
        {
        case 1:
          return DW_FORM_data1;
        case 2:
          return DW_FORM_data2;
        case 4:
          return DW_FORM_data4;
        case 8:
          return DW_FORM_data8;
        default:
          gcc_unreachable ();
        }
    case dw_val_class_const_double:
      switch (HOST_BITS_PER_WIDE_INT)
        {
        case 8:
          return DW_FORM_data2;
        case 16:
          return DW_FORM_data4;
        case 32:
          return DW_FORM_data8;
        case 64:
        default:
          return DW_FORM_block1;
        }
    case dw_val_class_vec:
      switch (constant_size (a->dw_attr_val.v.val_vec.length
                             * a->dw_attr_val.v.val_vec.elt_size))
        {
        case 1:
          return DW_FORM_block1;
        case 2:
          return DW_FORM_block2;
        case 4:
          return DW_FORM_block4;
        default:
          gcc_unreachable ();
        }
    case dw_val_class_flag:
      if (dwarf_version >= 4)
        {
          /* Currently all add_AT_flag calls pass in 1 as last argument,
             so DW_FORM_flag_present can be used.  If that ever changes,
             we'll need to use DW_FORM_flag and have some optimization
             in build_abbrev_table that will change those to
             DW_FORM_flag_present if it is set to 1 in all DIEs using
             the same abbrev entry.  */
          gcc_assert (a->dw_attr_val.v.val_flag == 1);
          return DW_FORM_flag_present;
        }
      return DW_FORM_flag;
    case dw_val_class_die_ref:
      if (AT_ref_external (a))
        return dwarf_version >= 4 ? DW_FORM_sig8 : DW_FORM_ref_addr;
      else
        return DW_FORM_ref;
    case dw_val_class_fde_ref:
      return DW_FORM_data;
    case dw_val_class_lbl_id:
      return DW_FORM_addr;
    case dw_val_class_lineptr:
    case dw_val_class_macptr:
      return dwarf_version >= 4 ? DW_FORM_sec_offset : DW_FORM_data;
    case dw_val_class_str:
      return AT_string_form (a);
    case dw_val_class_file:
      switch (constant_size (maybe_emit_file (a->dw_attr_val.v.val_file)))
        {
        case 1:
          return DW_FORM_data1;
        case 2:
          return DW_FORM_data2;
        case 4:
          return DW_FORM_data4;
        default:
          gcc_unreachable ();
        }

    case dw_val_class_data8:
      return DW_FORM_data8;

    default:
      gcc_unreachable ();
    }
}

/* Output the encoding of an attribute value.  */

static void
output_value_format (dw_attr_ref a)
{
  enum dwarf_form form = value_format (a);

  dw2_asm_output_data_uleb128 (form, "(%s)", dwarf_form_name (form));
}

/* Output the .debug_abbrev section which defines the DIE abbreviation
   table.  */

static void
output_abbrev_section (void)
{
  unsigned long abbrev_id;

  for (abbrev_id = 1; abbrev_id < abbrev_die_table_in_use; ++abbrev_id)
    {
      dw_die_ref abbrev = abbrev_die_table[abbrev_id];
      unsigned ix;
      dw_attr_ref a_attr;

      dw2_asm_output_data_uleb128 (abbrev_id, "(abbrev code)");
      dw2_asm_output_data_uleb128 (abbrev->die_tag, "(TAG: %s)",
                                   dwarf_tag_name (abbrev->die_tag));

      if (abbrev->die_child != NULL)
        dw2_asm_output_data (1, DW_children_yes, "DW_children_yes");
      else
        dw2_asm_output_data (1, DW_children_no, "DW_children_no");

      for (ix = 0; VEC_iterate (dw_attr_node, abbrev->die_attr, ix, a_attr);
           ix++)
        {
          dw2_asm_output_data_uleb128 (a_attr->dw_attr, "(%s)",
                                       dwarf_attr_name (a_attr->dw_attr));
          output_value_format (a_attr);
        }

      dw2_asm_output_data (1, 0, NULL);
      dw2_asm_output_data (1, 0, NULL);
    }

  /* Terminate the table.  */
  dw2_asm_output_data (1, 0, NULL);
}

/* Output a symbol we can use to refer to this DIE from another CU.  */

static inline void
output_die_symbol (dw_die_ref die)
{
  char *sym = die->die_id.die_symbol;

  if (sym == 0)
    return;

  if (strncmp (sym, DIE_LABEL_PREFIX, sizeof (DIE_LABEL_PREFIX) - 1) == 0)
    /* We make these global, not weak; if the target doesn't support
       .linkonce, it doesn't support combining the sections, so debugging
       will break.  */
    targetm.asm_out.globalize_label (asm_out_file, sym);

  ASM_OUTPUT_LABEL (asm_out_file, sym);
}

/* Return a new location list, given the begin and end range, and the
   expression.  */

static inline dw_loc_list_ref
new_loc_list (dw_loc_descr_ref expr, const char *begin, const char *end,
              const char *section)
{
  dw_loc_list_ref retlist = ggc_alloc_cleared_dw_loc_list_node ();

  retlist->begin = begin;
  retlist->end = end;
  retlist->expr = expr;
  retlist->section = section;

  return retlist;
}

/* Generate a new internal symbol for this location list node, if it
   hasn't got one yet.  */

static inline void
gen_llsym (dw_loc_list_ref list)
{
  gcc_assert (!list->ll_symbol);
  list->ll_symbol = gen_internal_sym ("LLST");
}

/* Output the location list given to us.  */

static void
output_loc_list (dw_loc_list_ref list_head)
{
  dw_loc_list_ref curr = list_head;

  if (list_head->emitted)
    return;
  list_head->emitted = true;

  ASM_OUTPUT_LABEL (asm_out_file, list_head->ll_symbol);

  /* Walk the location list, and output each range + expression.  */
  for (curr = list_head; curr != NULL; curr = curr->dw_loc_next)
    {
      unsigned long size;
      /* Don't output an entry that starts and ends at the same address.  */
      if (strcmp (curr->begin, curr->end) == 0)
        continue;
      if (!have_multiple_function_sections)
        {
          dw2_asm_output_delta (DWARF2_ADDR_SIZE, curr->begin, curr->section,
                                "Location list begin address (%s)",
                                list_head->ll_symbol);
          dw2_asm_output_delta (DWARF2_ADDR_SIZE, curr->end, curr->section,
                                "Location list end address (%s)",
                                list_head->ll_symbol);
        }
      else
        {
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, curr->begin,
                               "Location list begin address (%s)",
                               list_head->ll_symbol);
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, curr->end,
                               "Location list end address (%s)",
                               list_head->ll_symbol);
        }
      size = size_of_locs (curr->expr);

      /* Output the block length for this list of location operations.  */
      gcc_assert (size <= 0xffff);
      dw2_asm_output_data (2, size, "%s", "Location expression size");

      output_loc_sequence (curr->expr);
    }

  dw2_asm_output_data (DWARF2_ADDR_SIZE, 0,
                       "Location list terminator begin (%s)",
                       list_head->ll_symbol);
  dw2_asm_output_data (DWARF2_ADDR_SIZE, 0,
                       "Location list terminator end (%s)",
                       list_head->ll_symbol);
}

/* Output a type signature.  */

static inline void
output_signature (const char *sig, const char *name)
{
  int i;

  for (i = 0; i < DWARF_TYPE_SIGNATURE_SIZE; i++)
    dw2_asm_output_data (1, sig[i], i == 0 ? "%s" : NULL, name);
}

/* Output the DIE and its attributes.  Called recursively to generate
   the definitions of each child DIE.  */

static void
output_die (dw_die_ref die)
{
  dw_attr_ref a;
  dw_die_ref c;
  unsigned long size;
  unsigned ix;

  /* If someone in another CU might refer to us, set up a symbol for
     them to point to.  */
  if (dwarf_version < 4 && die->die_id.die_symbol)
    output_die_symbol (die);

  dw2_asm_output_data_uleb128 (die->die_abbrev, "(DIE (%#lx) %s)",
                               (unsigned long)die->die_offset,
                               dwarf_tag_name (die->die_tag));

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      const char *name = dwarf_attr_name (a->dw_attr);

      switch (AT_class (a))
        {
        case dw_val_class_addr:
          dw2_asm_output_addr_rtx (DWARF2_ADDR_SIZE, AT_addr (a), "%s", name);
          break;

        case dw_val_class_offset:
          dw2_asm_output_data (DWARF_OFFSET_SIZE, a->dw_attr_val.v.val_offset,
                               "%s", name);
          break;

        case dw_val_class_range_list:
          {
            char *p = strchr (ranges_section_label, '\0');

            sprintf (p, "+" HOST_WIDE_INT_PRINT_HEX,
                     a->dw_attr_val.v.val_offset);
            dw2_asm_output_offset (DWARF_OFFSET_SIZE, ranges_section_label,
                                   debug_ranges_section, "%s", name);
            *p = '\0';
          }
          break;

        case dw_val_class_loc:
          size = size_of_locs (AT_loc (a));

          /* Output the block length for this list of location operations.  */
          if (dwarf_version >= 4)
            dw2_asm_output_data_uleb128 (size, "%s", name);
          else
            dw2_asm_output_data (constant_size (size), size, "%s", name);

          output_loc_sequence (AT_loc (a));
          break;

        case dw_val_class_const:
          /* ??? It would be slightly more efficient to use a scheme like is
             used for unsigned constants below, but gdb 4.x does not sign
             extend.  Gdb 5.x does sign extend.  */
          dw2_asm_output_data_sleb128 (AT_int (a), "%s", name);
          break;

        case dw_val_class_unsigned_const:
          dw2_asm_output_data (constant_size (AT_unsigned (a)),
                               AT_unsigned (a), "%s", name);
          break;

        case dw_val_class_const_double:
          {
            unsigned HOST_WIDE_INT first, second;

            if (HOST_BITS_PER_WIDE_INT >= 64)
              dw2_asm_output_data (1,
                                   2 * HOST_BITS_PER_WIDE_INT
                                   / HOST_BITS_PER_CHAR,
                                   NULL);

            if (WORDS_BIG_ENDIAN)
              {
                first = a->dw_attr_val.v.val_double.high;
                second = a->dw_attr_val.v.val_double.low;
              }
            else
              {
                first = a->dw_attr_val.v.val_double.low;
                second = a->dw_attr_val.v.val_double.high;
              }

            dw2_asm_output_data (HOST_BITS_PER_WIDE_INT / HOST_BITS_PER_CHAR,
                                 first, name);
            dw2_asm_output_data (HOST_BITS_PER_WIDE_INT / HOST_BITS_PER_CHAR,
                                 second, NULL);
          }
          break;

        case dw_val_class_vec:
          {
            unsigned int elt_size = a->dw_attr_val.v.val_vec.elt_size;
            unsigned int len = a->dw_attr_val.v.val_vec.length;
            unsigned int i;
            unsigned char *p;

            dw2_asm_output_data (constant_size (len * elt_size),
                                 len * elt_size, "%s", name);
            if (elt_size > sizeof (HOST_WIDE_INT))
              {
                elt_size /= 2;
                len *= 2;
              }
            for (i = 0, p = a->dw_attr_val.v.val_vec.array;
                 i < len;
                 i++, p += elt_size)
              dw2_asm_output_data (elt_size, extract_int (p, elt_size),
                                   "fp or vector constant word %u", i);
            break;
          }

        case dw_val_class_flag:
          if (dwarf_version >= 4)
            {
              /* Currently all add_AT_flag calls pass in 1 as last argument,
                 so DW_FORM_flag_present can be used.  If that ever changes,
                 we'll need to use DW_FORM_flag and have some optimization
                 in build_abbrev_table that will change those to
                 DW_FORM_flag_present if it is set to 1 in all DIEs using
                 the same abbrev entry.  */
              gcc_assert (AT_flag (a) == 1);
              if (flag_debug_asm)
                fprintf (asm_out_file, "\t\t\t%s %s\n",
                         ASM_COMMENT_START, name);
              break;
            }
          dw2_asm_output_data (1, AT_flag (a), "%s", name);
          break;

        case dw_val_class_loc_list:
          {
            char *sym = AT_loc_list (a)->ll_symbol;

            gcc_assert (sym);
            dw2_asm_output_offset (DWARF_OFFSET_SIZE, sym, debug_loc_section,
                                   "%s", name);
          }
          break;

        case dw_val_class_die_ref:
          if (AT_ref_external (a))
            {
              if (dwarf_version >= 4)
                {
                  comdat_type_node_ref type_node =
                    AT_ref (a)->die_id.die_type_node;

                  gcc_assert (type_node);
                  output_signature (type_node->signature, name);
                }
              else
                {
                  char *sym = AT_ref (a)->die_id.die_symbol;
                  int size;

                  gcc_assert (sym);
                  /* In DWARF2, DW_FORM_ref_addr is sized by target address
                     length, whereas in DWARF3 it's always sized as an
                     offset.  */
                  if (dwarf_version == 2)
                    size = DWARF2_ADDR_SIZE;
                  else
                    size = DWARF_OFFSET_SIZE;
                  dw2_asm_output_offset (size, sym, debug_info_section, "%s",
                                         name);
                }
            }
          else
            {
              gcc_assert (AT_ref (a)->die_offset);
              dw2_asm_output_data (DWARF_OFFSET_SIZE, AT_ref (a)->die_offset,
                                   "%s", name);
            }
          break;

        case dw_val_class_fde_ref:
          {
            char l1[20];

            ASM_GENERATE_INTERNAL_LABEL (l1, FDE_LABEL,
                                         a->dw_attr_val.v.val_fde_index * 2);
            dw2_asm_output_offset (DWARF_OFFSET_SIZE, l1, debug_frame_section,
                                   "%s", name);
          }
          break;

        case dw_val_class_vms_delta:
          dw2_asm_output_vms_delta (DWARF_OFFSET_SIZE,
                                    AT_vms_delta2 (a), AT_vms_delta1 (a),
                                    "%s", name);
          break;

        case dw_val_class_lbl_id:
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, AT_lbl (a), "%s", name);
          break;

        case dw_val_class_lineptr:
          dw2_asm_output_offset (DWARF_OFFSET_SIZE, AT_lbl (a),
                                 debug_line_section, "%s", name);
          break;

        case dw_val_class_macptr:
          dw2_asm_output_offset (DWARF_OFFSET_SIZE, AT_lbl (a),
                                 debug_macinfo_section, "%s", name);
          break;

        case dw_val_class_str:
          if (AT_string_form (a) == DW_FORM_strp)
            dw2_asm_output_offset (DWARF_OFFSET_SIZE,
                                   a->dw_attr_val.v.val_str->label,
                                   debug_str_section,
                                   "%s: \"%s\"", name, AT_string (a));
          else
            dw2_asm_output_nstring (AT_string (a), -1, "%s", name);
          break;

        case dw_val_class_file:
          {
            int f = maybe_emit_file (a->dw_attr_val.v.val_file);

            dw2_asm_output_data (constant_size (f), f, "%s (%s)", name,
                                 a->dw_attr_val.v.val_file->filename);
            break;
          }

        case dw_val_class_data8:
          {
            int i;

            for (i = 0; i < 8; i++)
              dw2_asm_output_data (1, a->dw_attr_val.v.val_data8[i],
                                   i == 0 ? "%s" : NULL, name);
            break;
          }

        default:
          gcc_unreachable ();
        }
    }

  FOR_EACH_CHILD (die, c, output_die (c));

  /* Add null byte to terminate sibling list.  */
  if (die->die_child != NULL)
    dw2_asm_output_data (1, 0, "end of children of DIE %#lx",
                         (unsigned long) die->die_offset);
}

/* Output the compilation unit that appears at the beginning of the
   .debug_info section, and precedes the DIE descriptions.  */

static void
output_compilation_unit_header (void)
{
  int ver = dwarf_version;

  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  dw2_asm_output_data (DWARF_OFFSET_SIZE,
                       next_die_offset - DWARF_INITIAL_LENGTH_SIZE,
                       "Length of Compilation Unit Info");
  dw2_asm_output_data (2, ver, "DWARF version number");
  dw2_asm_output_offset (DWARF_OFFSET_SIZE, abbrev_section_label,
                         debug_abbrev_section,
                         "Offset Into Abbrev. Section");
  dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "Pointer Size (in bytes)");
}

/* Output the compilation unit DIE and its children.  */

static void
output_comp_unit (dw_die_ref die, int output_if_empty)
{
  const char *secname;
  char *oldsym, *tmp;

  /* Unless we are outputting main CU, we may throw away empty ones.  */
  if (!output_if_empty && die->die_child == NULL)
    return;

  /* Even if there are no children of this DIE, we must output the information
     about the compilation unit.  Otherwise, on an empty translation unit, we
     will generate a present, but empty, .debug_info section.  IRIX 6.5 `nm'
     will then complain when examining the file.  First mark all the DIEs in
     this CU so we know which get local refs.  */
  mark_dies (die);

  build_abbrev_table (die);

  /* Initialize the beginning DIE offset - and calculate sizes/offsets.  */
  next_die_offset = DWARF_COMPILE_UNIT_HEADER_SIZE;
  calc_die_sizes (die);

  oldsym = die->die_id.die_symbol;
  if (oldsym)
    {
      tmp = XALLOCAVEC (char, strlen (oldsym) + 24);

      sprintf (tmp, ".gnu.linkonce.wi.%s", oldsym);
      secname = tmp;
      die->die_id.die_symbol = NULL;
      switch_to_section (get_section (secname, SECTION_DEBUG, NULL));
    }
  else
    {
      switch_to_section (debug_info_section);
      ASM_OUTPUT_LABEL (asm_out_file, debug_info_section_label);
      info_section_emitted = true;
    }

  /* Output debugging information.  */
  output_compilation_unit_header ();
  output_die (die);

  /* Leave the marks on the main CU, so we can check them in
     output_pubnames.  */
  if (oldsym)
    {
      unmark_dies (die);
      die->die_id.die_symbol = oldsym;
    }
}

/* Output a comdat type unit DIE and its children.  */

static void
output_comdat_type_unit (comdat_type_node *node)
{
  const char *secname;
  char *tmp;
  int i;
#if defined (OBJECT_FORMAT_ELF)
  tree comdat_key;
#endif

  /* First mark all the DIEs in this CU so we know which get local refs.  */
  mark_dies (node->root_die);

  build_abbrev_table (node->root_die);

  /* Initialize the beginning DIE offset - and calculate sizes/offsets.  */
  next_die_offset = DWARF_COMDAT_TYPE_UNIT_HEADER_SIZE;
  calc_die_sizes (node->root_die);

#if defined (OBJECT_FORMAT_ELF)
  secname = ".debug_types";
  tmp = XALLOCAVEC (char, 4 + DWARF_TYPE_SIGNATURE_SIZE * 2);
  sprintf (tmp, "wt.");
  for (i = 0; i < DWARF_TYPE_SIGNATURE_SIZE; i++)
    sprintf (tmp + 3 + i * 2, "%02x", node->signature[i] & 0xff);
  comdat_key = get_identifier (tmp);
  targetm.asm_out.named_section (secname,
                                 SECTION_DEBUG | SECTION_LINKONCE,
                                 comdat_key);
#else
  tmp = XALLOCAVEC (char, 18 + DWARF_TYPE_SIGNATURE_SIZE * 2);
  sprintf (tmp, ".gnu.linkonce.wt.");
  for (i = 0; i < DWARF_TYPE_SIGNATURE_SIZE; i++)
    sprintf (tmp + 17 + i * 2, "%02x", node->signature[i] & 0xff);
  secname = tmp;
  switch_to_section (get_section (secname, SECTION_DEBUG, NULL));
#endif

  /* Output debugging information.  */
  output_compilation_unit_header ();
  output_signature (node->signature, "Type Signature");
  dw2_asm_output_data (DWARF_OFFSET_SIZE, node->type_die->die_offset,
                       "Offset to Type DIE");
  output_die (node->root_die);

  unmark_dies (node->root_die);
}

/* Return the DWARF2/3 pubname associated with a decl.  */

static const char *
dwarf2_name (tree decl, int scope)
{
  if (DECL_NAMELESS (decl))
    return NULL;
  return lang_hooks.dwarf_name (decl, scope ? 1 : 0);
}

/* Add a new entry to .debug_pubnames if appropriate.  */

static void
add_pubname_string (const char *str, dw_die_ref die)
{
  if (targetm.want_debug_pub_sections)
    {
      pubname_entry e;

      e.die = die;
      e.name = xstrdup (str);
      VEC_safe_push (pubname_entry, gc, pubname_table, &e);
    }
}

static void
add_pubname (tree decl, dw_die_ref die)
{
  if (targetm.want_debug_pub_sections && TREE_PUBLIC (decl))
    {
      const char *name = dwarf2_name (decl, 1);
      if (name)
        add_pubname_string (name, die);
    }
}

/* Add a new entry to .debug_pubtypes if appropriate.  */

static void
add_pubtype (tree decl, dw_die_ref die)
{
  pubname_entry e;

  if (!targetm.want_debug_pub_sections)
    return;

  e.name = NULL;
  if ((TREE_PUBLIC (decl)
       || is_cu_die (die->die_parent))
      && (die->die_tag == DW_TAG_typedef || COMPLETE_TYPE_P (decl)))
    {
      e.die = die;
      if (TYPE_P (decl))
        {
          if (TYPE_NAME (decl))
            {
              if (TREE_CODE (TYPE_NAME (decl)) == IDENTIFIER_NODE)
                e.name = IDENTIFIER_POINTER (TYPE_NAME (decl));
              else if (TREE_CODE (TYPE_NAME (decl)) == TYPE_DECL
                       && DECL_NAME (TYPE_NAME (decl)))
                e.name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (decl)));
              else
               e.name = xstrdup ((const char *) get_AT_string (die, DW_AT_name));
            }
        }
      else
        {
          e.name = dwarf2_name (decl, 1);
          if (e.name)
            e.name = xstrdup (e.name);
        }

      /* If we don't have a name for the type, there's no point in adding
         it to the table.  */
      if (e.name && e.name[0] != '\0')
        VEC_safe_push (pubname_entry, gc, pubtype_table, &e);
    }
}

/* Output the public names table used to speed up access to externally
   visible names; or the public types table used to find type definitions.  */

static void
output_pubnames (VEC (pubname_entry, gc) * names)
{
  unsigned i;
  unsigned long pubnames_length = size_of_pubnames (names);
  pubname_ref pub;

  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  if (names == pubname_table)
    dw2_asm_output_data (DWARF_OFFSET_SIZE, pubnames_length,
                         "Length of Public Names Info");
  else
    dw2_asm_output_data (DWARF_OFFSET_SIZE, pubnames_length,
                         "Length of Public Type Names Info");
  /* Version number for pubnames/pubtypes is still 2, even in DWARF3.  */
  dw2_asm_output_data (2, 2, "DWARF Version");
  dw2_asm_output_offset (DWARF_OFFSET_SIZE, debug_info_section_label,
                         debug_info_section,
                         "Offset of Compilation Unit Info");
  dw2_asm_output_data (DWARF_OFFSET_SIZE, next_die_offset,
                       "Compilation Unit Length");

  FOR_EACH_VEC_ELT (pubname_entry, names, i, pub)
    {
      /* We shouldn't see pubnames for DIEs outside of the main CU.  */
      if (names == pubname_table)
        gcc_assert (pub->die->die_mark);

      if (names != pubtype_table
          || pub->die->die_offset != 0
          || !flag_eliminate_unused_debug_types)
        {
          dw2_asm_output_data (DWARF_OFFSET_SIZE, pub->die->die_offset,
                               "DIE offset");

          dw2_asm_output_nstring (pub->name, -1, "external name");
        }
    }

  dw2_asm_output_data (DWARF_OFFSET_SIZE, 0, NULL);
}

/* Add a new entry to .debug_aranges if appropriate.  */

static void
add_arange (tree decl, dw_die_ref die)
{
  if (! DECL_SECTION_NAME (decl))
    return;

  if (arange_table_in_use == arange_table_allocated)
    {
      arange_table_allocated += ARANGE_TABLE_INCREMENT;
      arange_table = GGC_RESIZEVEC (dw_die_ref, arange_table,
                                    arange_table_allocated);
      memset (arange_table + arange_table_in_use, 0,
              ARANGE_TABLE_INCREMENT * sizeof (dw_die_ref));
    }

  arange_table[arange_table_in_use++] = die;
}

/* Output the information that goes into the .debug_aranges table.
   Namely, define the beginning and ending address range of the
   text section generated for this compilation unit.  */

static void
output_aranges (void)
{
  unsigned i;
  unsigned long aranges_length = size_of_aranges ();

  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  dw2_asm_output_data (DWARF_OFFSET_SIZE, aranges_length,
                       "Length of Address Ranges Info");
  /* Version number for aranges is still 2, even in DWARF3.  */
  dw2_asm_output_data (2, 2, "DWARF Version");
  dw2_asm_output_offset (DWARF_OFFSET_SIZE, debug_info_section_label,
                         debug_info_section,
                         "Offset of Compilation Unit Info");
  dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "Size of Address");
  dw2_asm_output_data (1, 0, "Size of Segment Descriptor");

  /* We need to align to twice the pointer size here.  */
  if (DWARF_ARANGES_PAD_SIZE)
    {
      /* Pad using a 2 byte words so that padding is correct for any
         pointer size.  */
      dw2_asm_output_data (2, 0, "Pad to %d byte boundary",
                           2 * DWARF2_ADDR_SIZE);
      for (i = 2; i < (unsigned) DWARF_ARANGES_PAD_SIZE; i += 2)
        dw2_asm_output_data (2, 0, NULL);
    }

  /* It is necessary not to output these entries if the sections were
     not used; if the sections were not used, the length will be 0 and
     the address may end up as 0 if the section is discarded by ld
     --gc-sections, leaving an invalid (0, 0) entry that can be
     confused with the terminator.  */
  if (text_section_used)
    {
      dw2_asm_output_addr (DWARF2_ADDR_SIZE, text_section_label, "Address");
      dw2_asm_output_delta (DWARF2_ADDR_SIZE, text_end_label,
                            text_section_label, "Length");
    }
  if (cold_text_section_used)
    {
      dw2_asm_output_addr (DWARF2_ADDR_SIZE, cold_text_section_label,
                           "Address");
      dw2_asm_output_delta (DWARF2_ADDR_SIZE, cold_end_label,
                            cold_text_section_label, "Length");
    }

  for (i = 0; i < arange_table_in_use; i++)
    {
      dw_die_ref die = arange_table[i];

      /* We shouldn't see aranges for DIEs outside of the main CU.  */
      gcc_assert (die->die_mark);

      if (die->die_tag == DW_TAG_subprogram)
        {
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, get_AT_low_pc (die),
                               "Address");
          dw2_asm_output_delta (DWARF2_ADDR_SIZE, get_AT_hi_pc (die),
                                get_AT_low_pc (die), "Length");
        }
      else
        {
          /* A static variable; extract the symbol from DW_AT_location.
             Note that this code isn't currently hit, as we only emit
             aranges for functions (jason 9/23/99).  */
          dw_attr_ref a = get_AT (die, DW_AT_location);
          dw_loc_descr_ref loc;

          gcc_assert (a && AT_class (a) == dw_val_class_loc);

          loc = AT_loc (a);
          gcc_assert (loc->dw_loc_opc == DW_OP_addr);

          dw2_asm_output_addr_rtx (DWARF2_ADDR_SIZE,
                                   loc->dw_loc_oprnd1.v.val_addr, "Address");
          dw2_asm_output_data (DWARF2_ADDR_SIZE,
                               get_AT_unsigned (die, DW_AT_byte_size),
                               "Length");
        }
    }

  /* Output the terminator words.  */
  dw2_asm_output_data (DWARF2_ADDR_SIZE, 0, NULL);
  dw2_asm_output_data (DWARF2_ADDR_SIZE, 0, NULL);
}

/* Add a new entry to .debug_ranges.  Return the offset at which it
   was placed.  */

static unsigned int
add_ranges_num (int num)
{
  unsigned int in_use = ranges_table_in_use;

  if (in_use == ranges_table_allocated)
    {
      ranges_table_allocated += RANGES_TABLE_INCREMENT;
      ranges_table = GGC_RESIZEVEC (struct dw_ranges_struct, ranges_table,
                                    ranges_table_allocated);
      memset (ranges_table + ranges_table_in_use, 0,
              RANGES_TABLE_INCREMENT * sizeof (struct dw_ranges_struct));
    }

  ranges_table[in_use].num = num;
  ranges_table_in_use = in_use + 1;

  return in_use * 2 * DWARF2_ADDR_SIZE;
}

/* Add a new entry to .debug_ranges corresponding to a block, or a
   range terminator if BLOCK is NULL.  */

static unsigned int
add_ranges (const_tree block)
{
  return add_ranges_num (block ? BLOCK_NUMBER (block) : 0);
}

/* Add a new entry to .debug_ranges corresponding to a pair of
   labels.  */

static void
add_ranges_by_labels (dw_die_ref die, const char *begin, const char *end,
                      bool *added)
{
  unsigned int in_use = ranges_by_label_in_use;
  unsigned int offset;

  if (in_use == ranges_by_label_allocated)
    {
      ranges_by_label_allocated += RANGES_TABLE_INCREMENT;
      ranges_by_label = GGC_RESIZEVEC (struct dw_ranges_by_label_struct,
                                       ranges_by_label,
                                       ranges_by_label_allocated);
      memset (ranges_by_label + ranges_by_label_in_use, 0,
              RANGES_TABLE_INCREMENT
              * sizeof (struct dw_ranges_by_label_struct));
    }

  ranges_by_label[in_use].begin = begin;
  ranges_by_label[in_use].end = end;
  ranges_by_label_in_use = in_use + 1;

  offset = add_ranges_num (-(int)in_use - 1);
  if (!*added)
    {
      add_AT_range_list (die, DW_AT_ranges, offset);
      *added = true;
    }
}

static void
output_ranges (void)
{
  unsigned i;
  static const char *const start_fmt = "Offset %#x";
  const char *fmt = start_fmt;

  for (i = 0; i < ranges_table_in_use; i++)
    {
      int block_num = ranges_table[i].num;

      if (block_num > 0)
        {
          char blabel[MAX_ARTIFICIAL_LABEL_BYTES];
          char elabel[MAX_ARTIFICIAL_LABEL_BYTES];

          ASM_GENERATE_INTERNAL_LABEL (blabel, BLOCK_BEGIN_LABEL, block_num);
          ASM_GENERATE_INTERNAL_LABEL (elabel, BLOCK_END_LABEL, block_num);

          /* If all code is in the text section, then the compilation
             unit base address defaults to DW_AT_low_pc, which is the
             base of the text section.  */
          if (!have_multiple_function_sections)
            {
              dw2_asm_output_delta (DWARF2_ADDR_SIZE, blabel,
                                    text_section_label,
                                    fmt, i * 2 * DWARF2_ADDR_SIZE);
              dw2_asm_output_delta (DWARF2_ADDR_SIZE, elabel,
                                    text_section_label, NULL);
            }

          /* Otherwise, the compilation unit base address is zero,
             which allows us to use absolute addresses, and not worry
             about whether the target supports cross-section
             arithmetic.  */
          else
            {
              dw2_asm_output_addr (DWARF2_ADDR_SIZE, blabel,
                                   fmt, i * 2 * DWARF2_ADDR_SIZE);
              dw2_asm_output_addr (DWARF2_ADDR_SIZE, elabel, NULL);
            }

          fmt = NULL;
        }

      /* Negative block_num stands for an index into ranges_by_label.  */
      else if (block_num < 0)
        {
          int lab_idx = - block_num - 1;

          if (!have_multiple_function_sections)
            {
              gcc_unreachable ();
#if 0
              /* If we ever use add_ranges_by_labels () for a single
                 function section, all we have to do is to take out
                 the #if 0 above.  */
              dw2_asm_output_delta (DWARF2_ADDR_SIZE,
                                    ranges_by_label[lab_idx].begin,
                                    text_section_label,
                                    fmt, i * 2 * DWARF2_ADDR_SIZE);
              dw2_asm_output_delta (DWARF2_ADDR_SIZE,
                                    ranges_by_label[lab_idx].end,
                                    text_section_label, NULL);
#endif
            }
          else
            {
              dw2_asm_output_addr (DWARF2_ADDR_SIZE,
                                   ranges_by_label[lab_idx].begin,
                                   fmt, i * 2 * DWARF2_ADDR_SIZE);
              dw2_asm_output_addr (DWARF2_ADDR_SIZE,
                                   ranges_by_label[lab_idx].end,
                                   NULL);
            }
        }
      else
        {
          dw2_asm_output_data (DWARF2_ADDR_SIZE, 0, NULL);
          dw2_asm_output_data (DWARF2_ADDR_SIZE, 0, NULL);
          fmt = start_fmt;
        }
    }
}

/* Data structure containing information about input files.  */
struct file_info
{
  const char *path;     /* Complete file name.  */
  const char *fname;    /* File name part.  */
  int length;           /* Length of entire string.  */
  struct dwarf_file_data * file_idx;    /* Index in input file table.  */
  int dir_idx;          /* Index in directory table.  */
};

/* Data structure containing information about directories with source
   files.  */
struct dir_info
{
  const char *path;     /* Path including directory name.  */
  int length;           /* Path length.  */
  int prefix;           /* Index of directory entry which is a prefix.  */
  int count;            /* Number of files in this directory.  */
  int dir_idx;          /* Index of directory used as base.  */
};

/* Callback function for file_info comparison.  We sort by looking at
   the directories in the path.  */

static int
file_info_cmp (const void *p1, const void *p2)
{
  const struct file_info *const s1 = (const struct file_info *) p1;
  const struct file_info *const s2 = (const struct file_info *) p2;
  const unsigned char *cp1;
  const unsigned char *cp2;

  /* Take care of file names without directories.  We need to make sure that
     we return consistent values to qsort since some will get confused if
     we return the same value when identical operands are passed in opposite
     orders.  So if neither has a directory, return 0 and otherwise return
     1 or -1 depending on which one has the directory.  */
  if ((s1->path == s1->fname || s2->path == s2->fname))
    return (s2->path == s2->fname) - (s1->path == s1->fname);

  cp1 = (const unsigned char *) s1->path;
  cp2 = (const unsigned char *) s2->path;

  while (1)
    {
      ++cp1;
      ++cp2;
      /* Reached the end of the first path?  If so, handle like above.  */
      if ((cp1 == (const unsigned char *) s1->fname)
          || (cp2 == (const unsigned char *) s2->fname))
        return ((cp2 == (const unsigned char *) s2->fname)
                - (cp1 == (const unsigned char *) s1->fname));

      /* Character of current path component the same?  */
      else if (*cp1 != *cp2)
        return *cp1 - *cp2;
    }
}

struct file_name_acquire_data
{
  struct file_info *files;
  int used_files;
  int max_files;
};

/* Traversal function for the hash table.  */

static int
file_name_acquire (void ** slot, void *data)
{
  struct file_name_acquire_data *fnad = (struct file_name_acquire_data *) data;
  struct dwarf_file_data *d = (struct dwarf_file_data *) *slot;
  struct file_info *fi;
  const char *f;

  gcc_assert (fnad->max_files >= d->emitted_number);

  if (! d->emitted_number)
    return 1;

  gcc_assert (fnad->max_files != fnad->used_files);

  fi = fnad->files + fnad->used_files++;

  /* Skip all leading "./".  */
  f = d->filename;
  while (f[0] == '.' && IS_DIR_SEPARATOR (f[1]))
    f += 2;

  /* Create a new array entry.  */
  fi->path = f;
  fi->length = strlen (f);
  fi->file_idx = d;

  /* Search for the file name part.  */
  f = strrchr (f, DIR_SEPARATOR);
#if defined (DIR_SEPARATOR_2)
  {
    char *g = strrchr (fi->path, DIR_SEPARATOR_2);

    if (g != NULL)
      {
        if (f == NULL || f < g)
          f = g;
      }
  }
#endif

  fi->fname = f == NULL ? fi->path : f + 1;
  return 1;
}

/* Output the directory table and the file name table.  We try to minimize
   the total amount of memory needed.  A heuristic is used to avoid large
   slowdowns with many input files.  */

static void
output_file_names (void)
{
  struct file_name_acquire_data fnad;
  int numfiles;
  struct file_info *files;
  struct dir_info *dirs;
  int *saved;
  int *savehere;
  int *backmap;
  int ndirs;
  int idx_offset;
  int i;

  if (!last_emitted_file)
    {
      dw2_asm_output_data (1, 0, "End directory table");
      dw2_asm_output_data (1, 0, "End file name table");
      return;
    }

  numfiles = last_emitted_file->emitted_number;

  /* Allocate the various arrays we need.  */
  files = XALLOCAVEC (struct file_info, numfiles);
  dirs = XALLOCAVEC (struct dir_info, numfiles);

  fnad.files = files;
  fnad.used_files = 0;
  fnad.max_files = numfiles;
  htab_traverse (file_table, file_name_acquire, &fnad);
  gcc_assert (fnad.used_files == fnad.max_files);

  qsort (files, numfiles, sizeof (files[0]), file_info_cmp);

  /* Find all the different directories used.  */
  dirs[0].path = files[0].path;
  dirs[0].length = files[0].fname - files[0].path;
  dirs[0].prefix = -1;
  dirs[0].count = 1;
  dirs[0].dir_idx = 0;
  files[0].dir_idx = 0;
  ndirs = 1;

  for (i = 1; i < numfiles; i++)
    if (files[i].fname - files[i].path == dirs[ndirs - 1].length
        && memcmp (dirs[ndirs - 1].path, files[i].path,
                   dirs[ndirs - 1].length) == 0)
      {
        /* Same directory as last entry.  */
        files[i].dir_idx = ndirs - 1;
        ++dirs[ndirs - 1].count;
      }
    else
      {
        int j;

        /* This is a new directory.  */
        dirs[ndirs].path = files[i].path;
        dirs[ndirs].length = files[i].fname - files[i].path;
        dirs[ndirs].count = 1;
        dirs[ndirs].dir_idx = ndirs;
        files[i].dir_idx = ndirs;

        /* Search for a prefix.  */
        dirs[ndirs].prefix = -1;
        for (j = 0; j < ndirs; j++)
          if (dirs[j].length < dirs[ndirs].length
              && dirs[j].length > 1
              && (dirs[ndirs].prefix == -1
                  || dirs[j].length > dirs[dirs[ndirs].prefix].length)
              && memcmp (dirs[j].path, dirs[ndirs].path, dirs[j].length) == 0)
            dirs[ndirs].prefix = j;

        ++ndirs;
      }

  /* Now to the actual work.  We have to find a subset of the directories which
     allow expressing the file name using references to the directory table
     with the least amount of characters.  We do not do an exhaustive search
     where we would have to check out every combination of every single
     possible prefix.  Instead we use a heuristic which provides nearly optimal
     results in most cases and never is much off.  */
  saved = XALLOCAVEC (int, ndirs);
  savehere = XALLOCAVEC (int, ndirs);

  memset (saved, '\0', ndirs * sizeof (saved[0]));
  for (i = 0; i < ndirs; i++)
    {
      int j;
      int total;

      /* We can always save some space for the current directory.  But this
         does not mean it will be enough to justify adding the directory.  */
      savehere[i] = dirs[i].length;
      total = (savehere[i] - saved[i]) * dirs[i].count;

      for (j = i + 1; j < ndirs; j++)
        {
          savehere[j] = 0;
          if (saved[j] < dirs[i].length)
            {
              /* Determine whether the dirs[i] path is a prefix of the
                 dirs[j] path.  */
              int k;

              k = dirs[j].prefix;
              while (k != -1 && k != (int) i)
                k = dirs[k].prefix;

              if (k == (int) i)
                {
                  /* Yes it is.  We can possibly save some memory by
                     writing the filenames in dirs[j] relative to
                     dirs[i].  */
                  savehere[j] = dirs[i].length;
                  total += (savehere[j] - saved[j]) * dirs[j].count;
                }
            }
        }

      /* Check whether we can save enough to justify adding the dirs[i]
         directory.  */
      if (total > dirs[i].length + 1)
        {
          /* It's worthwhile adding.  */
          for (j = i; j < ndirs; j++)
            if (savehere[j] > 0)
              {
                /* Remember how much we saved for this directory so far.  */
                saved[j] = savehere[j];

                /* Remember the prefix directory.  */
                dirs[j].dir_idx = i;
              }
        }
    }

  /* Emit the directory name table.  */
  idx_offset = dirs[0].length > 0 ? 1 : 0;
  for (i = 1 - idx_offset; i < ndirs; i++)
    dw2_asm_output_nstring (dirs[i].path,
                            dirs[i].length
                             - !DWARF2_DIR_SHOULD_END_WITH_SEPARATOR,
                            "Directory Entry: %#x", i + idx_offset);

  dw2_asm_output_data (1, 0, "End directory table");

  /* We have to emit them in the order of emitted_number since that's
     used in the debug info generation.  To do this efficiently we
     generate a back-mapping of the indices first.  */
  backmap = XALLOCAVEC (int, numfiles);
  for (i = 0; i < numfiles; i++)
    backmap[files[i].file_idx->emitted_number - 1] = i;

  /* Now write all the file names.  */
  for (i = 0; i < numfiles; i++)
    {
      int file_idx = backmap[i];
      int dir_idx = dirs[files[file_idx].dir_idx].dir_idx;

#ifdef VMS_DEBUGGING_INFO
#define MAX_VMS_VERSION_LEN 6 /* ";32768" */

      /* Setting these fields can lead to debugger miscomparisons,
         but VMS Debug requires them to be set correctly.  */

      int ver;
      long long cdt;
      long siz;
      int maxfilelen = strlen (files[file_idx].path)
                               + dirs[dir_idx].length
                               + MAX_VMS_VERSION_LEN + 1;
      char *filebuf = XALLOCAVEC (char, maxfilelen);

      vms_file_stats_name (files[file_idx].path, 0, 0, 0, &ver);
      snprintf (filebuf, maxfilelen, "%s;%d",
                files[file_idx].path + dirs[dir_idx].length, ver);

      dw2_asm_output_nstring
        (filebuf, -1, "File Entry: %#x", (unsigned) i + 1);

      /* Include directory index.  */
      dw2_asm_output_data_uleb128 (dir_idx + idx_offset, NULL);

      /* Modification time.  */
      dw2_asm_output_data_uleb128
        ((vms_file_stats_name (files[file_idx].path, &cdt, 0, 0, 0) == 0)
          ? cdt : 0,
         NULL);

      /* File length in bytes.  */
      dw2_asm_output_data_uleb128
        ((vms_file_stats_name (files[file_idx].path, 0, &siz, 0, 0) == 0)
          ? siz : 0,
         NULL);
#else
      dw2_asm_output_nstring (files[file_idx].path + dirs[dir_idx].length, -1,
                              "File Entry: %#x", (unsigned) i + 1);

      /* Include directory index.  */
      dw2_asm_output_data_uleb128 (dir_idx + idx_offset, NULL);

      /* Modification time.  */
      dw2_asm_output_data_uleb128 (0, NULL);

      /* File length in bytes.  */
      dw2_asm_output_data_uleb128 (0, NULL);
#endif /* VMS_DEBUGGING_INFO */
    }

  dw2_asm_output_data (1, 0, "End file name table");
}


/* Output the source line number correspondence information.  This
   information goes into the .debug_line section.  */

static void
output_line_info (void)
{
  char l1[20], l2[20], p1[20], p2[20];
  char line_label[MAX_ARTIFICIAL_LABEL_BYTES];
  char prev_line_label[MAX_ARTIFICIAL_LABEL_BYTES];
  unsigned opc;
  unsigned n_op_args;
  unsigned long lt_index;
  unsigned long current_line;
  long line_offset;
  long line_delta;
  unsigned long current_file;
  unsigned long function;
  int ver = dwarf_version;

  ASM_GENERATE_INTERNAL_LABEL (l1, LINE_NUMBER_BEGIN_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (l2, LINE_NUMBER_END_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (p1, LN_PROLOG_AS_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (p2, LN_PROLOG_END_LABEL, 0);

  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  dw2_asm_output_delta (DWARF_OFFSET_SIZE, l2, l1,
                        "Length of Source Line Info");
  ASM_OUTPUT_LABEL (asm_out_file, l1);

  dw2_asm_output_data (2, ver, "DWARF Version");
  dw2_asm_output_delta (DWARF_OFFSET_SIZE, p2, p1, "Prolog Length");
  ASM_OUTPUT_LABEL (asm_out_file, p1);

  /* Define the architecture-dependent minimum instruction length (in
   bytes).  In this implementation of DWARF, this field is used for
   information purposes only.  Since GCC generates assembly language,
   we have no a priori knowledge of how many instruction bytes are
   generated for each source line, and therefore can use only the
   DW_LNE_set_address and DW_LNS_fixed_advance_pc line information
   commands.  Accordingly, we fix this as `1', which is "correct
   enough" for all architectures, and don't let the target override.  */
  dw2_asm_output_data (1, 1,
                       "Minimum Instruction Length");

  if (ver >= 4)
    dw2_asm_output_data (1, DWARF_LINE_DEFAULT_MAX_OPS_PER_INSN,
                         "Maximum Operations Per Instruction");
  dw2_asm_output_data (1, DWARF_LINE_DEFAULT_IS_STMT_START,
                       "Default is_stmt_start flag");
  dw2_asm_output_data (1, DWARF_LINE_BASE,
                       "Line Base Value (Special Opcodes)");
  dw2_asm_output_data (1, DWARF_LINE_RANGE,
                       "Line Range Value (Special Opcodes)");
  dw2_asm_output_data (1, DWARF_LINE_OPCODE_BASE,
                       "Special Opcode Base");

  for (opc = 1; opc < DWARF_LINE_OPCODE_BASE; opc++)
    {
      switch (opc)
        {
        case DW_LNS_advance_pc:
        case DW_LNS_advance_line:
        case DW_LNS_set_file:
        case DW_LNS_set_column:
        case DW_LNS_fixed_advance_pc:
          n_op_args = 1;
          break;
        default:
          n_op_args = 0;
          break;
        }

      dw2_asm_output_data (1, n_op_args, "opcode: %#x has %d args",
                           opc, n_op_args);
    }

  /* Write out the information about the files we use.  */
  output_file_names ();
  ASM_OUTPUT_LABEL (asm_out_file, p2);

  /* We used to set the address register to the first location in the text
     section here, but that didn't accomplish anything since we already
     have a line note for the opening brace of the first function.  */

  /* Generate the line number to PC correspondence table, encoded as
     a series of state machine operations.  */
  current_file = 1;
  current_line = 1;

  if (cfun && in_cold_section_p)
    strcpy (prev_line_label, crtl->subsections.cold_section_label);
  else
    strcpy (prev_line_label, text_section_label);
  for (lt_index = 1; lt_index < line_info_table_in_use; ++lt_index)
    {
      dw_line_info_ref line_info = &line_info_table[lt_index];

#if 0
      /* Disable this optimization for now; GDB wants to see two line notes
         at the beginning of a function so it can find the end of the
         prologue.  */

      /* Don't emit anything for redundant notes.  Just updating the
         address doesn't accomplish anything, because we already assume
         that anything after the last address is this line.  */
      if (line_info->dw_line_num == current_line
          && line_info->dw_file_num == current_file)
        continue;
#endif

      /* Emit debug info for the address of the current line.

         Unfortunately, we have little choice here currently, and must always
         use the most general form.  GCC does not know the address delta
         itself, so we can't use DW_LNS_advance_pc.  Many ports do have length
         attributes which will give an upper bound on the address range.  We
         could perhaps use length attributes to determine when it is safe to
         use DW_LNS_fixed_advance_pc.  */

      ASM_GENERATE_INTERNAL_LABEL (line_label, LINE_CODE_LABEL, lt_index);
      if (0)
        {
          /* This can handle deltas up to 0xffff.  This takes 3 bytes.  */
          dw2_asm_output_data (1, DW_LNS_fixed_advance_pc,
                               "DW_LNS_fixed_advance_pc");
          dw2_asm_output_delta (2, line_label, prev_line_label, NULL);
        }
      else
        {
          /* This can handle any delta.  This takes
             4+DWARF2_ADDR_SIZE bytes.  */
          dw2_asm_output_data (1, 0, "DW_LNE_set_address");
          dw2_asm_output_data_uleb128 (1 + DWARF2_ADDR_SIZE, NULL);
          dw2_asm_output_data (1, DW_LNE_set_address, NULL);
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, line_label, NULL);
        }

      strcpy (prev_line_label, line_label);

      /* Emit debug info for the source file of the current line, if
         different from the previous line.  */
      if (line_info->dw_file_num != current_file)
        {
          current_file = line_info->dw_file_num;
          dw2_asm_output_data (1, DW_LNS_set_file, "DW_LNS_set_file");
          dw2_asm_output_data_uleb128 (current_file, "%lu", current_file);
        }

      /* Emit debug info for the current line number, choosing the encoding
         that uses the least amount of space.  */
      if (line_info->dw_line_num != current_line)
        {
          line_offset = line_info->dw_line_num - current_line;
          line_delta = line_offset - DWARF_LINE_BASE;
          current_line = line_info->dw_line_num;
          if (line_delta >= 0 && line_delta < (DWARF_LINE_RANGE - 1))
            /* This can handle deltas from -10 to 234, using the current
               definitions of DWARF_LINE_BASE and DWARF_LINE_RANGE.  This
               takes 1 byte.  */
            dw2_asm_output_data (1, DWARF_LINE_OPCODE_BASE + line_delta,
                                 "line %lu", current_line);
          else
            {
              /* This can handle any delta.  This takes at least 4 bytes,
                 depending on the value being encoded.  */
              dw2_asm_output_data (1, DW_LNS_advance_line,
                                   "advance to line %lu", current_line);
              dw2_asm_output_data_sleb128 (line_offset, NULL);
              dw2_asm_output_data (1, DW_LNS_copy, "DW_LNS_copy");
            }
        }
      else
        /* We still need to start a new row, so output a copy insn.  */
        dw2_asm_output_data (1, DW_LNS_copy, "DW_LNS_copy");
    }

  /* Emit debug info for the address of the end of the function.  */
  if (0)
    {
      dw2_asm_output_data (1, DW_LNS_fixed_advance_pc,
                           "DW_LNS_fixed_advance_pc");
      dw2_asm_output_delta (2, text_end_label, prev_line_label, NULL);
    }
  else
    {
      dw2_asm_output_data (1, 0, "DW_LNE_set_address");
      dw2_asm_output_data_uleb128 (1 + DWARF2_ADDR_SIZE, NULL);
      dw2_asm_output_data (1, DW_LNE_set_address, NULL);
      dw2_asm_output_addr (DWARF2_ADDR_SIZE, text_end_label, NULL);
    }

  dw2_asm_output_data (1, 0, "DW_LNE_end_sequence");
  dw2_asm_output_data_uleb128 (1, NULL);
  dw2_asm_output_data (1, DW_LNE_end_sequence, NULL);

  function = 0;
  current_file = 1;
  current_line = 1;
  for (lt_index = 0; lt_index < separate_line_info_table_in_use;)
    {
      dw_separate_line_info_ref line_info
        = &separate_line_info_table[lt_index];

#if 0
      /* Don't emit anything for redundant notes.  */
      if (line_info->dw_line_num == current_line
          && line_info->dw_file_num == current_file
          && line_info->function == function)
        goto cont;
#endif

      /* Emit debug info for the address of the current line.  If this is
         a new function, or the first line of a function, then we need
         to handle it differently.  */
      ASM_GENERATE_INTERNAL_LABEL (line_label, SEPARATE_LINE_CODE_LABEL,
                                   lt_index);
      if (function != line_info->function)
        {
          function = line_info->function;

          /* Set the address register to the first line in the function.  */
          dw2_asm_output_data (1, 0, "DW_LNE_set_address");
          dw2_asm_output_data_uleb128 (1 + DWARF2_ADDR_SIZE, NULL);
          dw2_asm_output_data (1, DW_LNE_set_address, NULL);
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, line_label, NULL);
        }
      else
        {
          /* ??? See the DW_LNS_advance_pc comment above.  */
          if (0)
            {
              dw2_asm_output_data (1, DW_LNS_fixed_advance_pc,
                                   "DW_LNS_fixed_advance_pc");
              dw2_asm_output_delta (2, line_label, prev_line_label, NULL);
            }
          else
            {
              dw2_asm_output_data (1, 0, "DW_LNE_set_address");
              dw2_asm_output_data_uleb128 (1 + DWARF2_ADDR_SIZE, NULL);
              dw2_asm_output_data (1, DW_LNE_set_address, NULL);
              dw2_asm_output_addr (DWARF2_ADDR_SIZE, line_label, NULL);
            }
        }

      strcpy (prev_line_label, line_label);

      /* Emit debug info for the source file of the current line, if
         different from the previous line.  */
      if (line_info->dw_file_num != current_file)
        {
          current_file = line_info->dw_file_num;
          dw2_asm_output_data (1, DW_LNS_set_file, "DW_LNS_set_file");
          dw2_asm_output_data_uleb128 (current_file, "%lu", current_file);
        }

      /* Emit debug info for the current line number, choosing the encoding
         that uses the least amount of space.  */
      if (line_info->dw_line_num != current_line)
        {
          line_offset = line_info->dw_line_num - current_line;
          line_delta = line_offset - DWARF_LINE_BASE;
          current_line = line_info->dw_line_num;
          if (line_delta >= 0 && line_delta < (DWARF_LINE_RANGE - 1))
            dw2_asm_output_data (1, DWARF_LINE_OPCODE_BASE + line_delta,
                                 "line %lu", current_line);
          else
            {
              dw2_asm_output_data (1, DW_LNS_advance_line,
                                   "advance to line %lu", current_line);
              dw2_asm_output_data_sleb128 (line_offset, NULL);
              dw2_asm_output_data (1, DW_LNS_copy, "DW_LNS_copy");
            }
        }
      else
        dw2_asm_output_data (1, DW_LNS_copy, "DW_LNS_copy");

#if 0
    cont:
#endif

      lt_index++;

      /* If we're done with a function, end its sequence.  */
      if (lt_index == separate_line_info_table_in_use
          || separate_line_info_table[lt_index].function != function)
        {
          current_file = 1;
          current_line = 1;

          /* Emit debug info for the address of the end of the function.  */
          ASM_GENERATE_INTERNAL_LABEL (line_label, FUNC_END_LABEL, function);
          if (0)
            {
              dw2_asm_output_data (1, DW_LNS_fixed_advance_pc,
                                   "DW_LNS_fixed_advance_pc");
              dw2_asm_output_delta (2, line_label, prev_line_label, NULL);
            }
          else
            {
              dw2_asm_output_data (1, 0, "DW_LNE_set_address");
              dw2_asm_output_data_uleb128 (1 + DWARF2_ADDR_SIZE, NULL);
              dw2_asm_output_data (1, DW_LNE_set_address, NULL);
              dw2_asm_output_addr (DWARF2_ADDR_SIZE, line_label, NULL);
            }

          /* Output the marker for the end of this sequence.  */
          dw2_asm_output_data (1, 0, "DW_LNE_end_sequence");
          dw2_asm_output_data_uleb128 (1, NULL);
          dw2_asm_output_data (1, DW_LNE_end_sequence, NULL);
        }
    }

  /* Output the marker for the end of the line number info.  */
  ASM_OUTPUT_LABEL (asm_out_file, l2);
}

/* Return the size of the .debug_dcall table for the compilation unit.  */

static unsigned long
size_of_dcall_table (void)
{
  unsigned long size;
  unsigned int i;
  dcall_entry *p;
  tree last_poc_decl = NULL;

  /* Header:  version + debug info section pointer + pointer size.  */
  size = 2 + DWARF_OFFSET_SIZE + 1;

  /* Each entry:  code label + DIE offset.  */
  FOR_EACH_VEC_ELT (dcall_entry, dcall_table, i, p)
    {
      gcc_assert (p->targ_die != NULL);
      /* Insert a "from" entry when the point-of-call DIE offset changes.  */
      if (p->poc_decl != last_poc_decl)
        {
          dw_die_ref poc_die = lookup_decl_die (p->poc_decl);
          gcc_assert (poc_die);
          last_poc_decl = p->poc_decl;
          if (poc_die)
            size += (DWARF_OFFSET_SIZE
                     + size_of_uleb128 (poc_die->die_offset));
        }
      size += DWARF_OFFSET_SIZE + size_of_uleb128 (p->targ_die->die_offset);
    }

  return size;
}

/* Output the direct call table used to disambiguate PC values when
   identical function have been merged.  */

static void
output_dcall_table (void)
{
  unsigned i;
  unsigned long dcall_length = size_of_dcall_table ();
  dcall_entry *p;
  char poc_label[MAX_ARTIFICIAL_LABEL_BYTES];
  tree last_poc_decl = NULL;

  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  dw2_asm_output_data (DWARF_OFFSET_SIZE, dcall_length,
                       "Length of Direct Call Table");
  dw2_asm_output_data (2, 4, "Version number");
  dw2_asm_output_offset (DWARF_OFFSET_SIZE, debug_info_section_label,
                         debug_info_section,
                         "Offset of Compilation Unit Info");
  dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "Pointer Size (in bytes)");

  FOR_EACH_VEC_ELT (dcall_entry, dcall_table, i, p)
    {
      /* Insert a "from" entry when the point-of-call DIE offset changes.  */
      if (p->poc_decl != last_poc_decl)
        {
          dw_die_ref poc_die = lookup_decl_die (p->poc_decl);
          last_poc_decl = p->poc_decl;
          if (poc_die)
            {
              dw2_asm_output_data (DWARF_OFFSET_SIZE, 0, "New caller");
              dw2_asm_output_data_uleb128 (poc_die->die_offset,
                                           "Caller DIE offset");
            }
        }
      ASM_GENERATE_INTERNAL_LABEL (poc_label, "LPOC", p->poc_label_num);
      dw2_asm_output_addr (DWARF_OFFSET_SIZE, poc_label, "Point of call");
      dw2_asm_output_data_uleb128 (p->targ_die->die_offset,
                                   "Callee DIE offset");
    }
}
\f
/* Return the size of the .debug_vcall table for the compilation unit.  */

static unsigned long
size_of_vcall_table (void)
{
  unsigned long size;
  unsigned int i;
  vcall_entry *p;

  /* Header:  version + pointer size.  */
  size = 2 + 1;

  /* Each entry:  code label + vtable slot index.  */
  FOR_EACH_VEC_ELT (vcall_entry, vcall_table, i, p)
    size += DWARF_OFFSET_SIZE + size_of_uleb128 (p->vtable_slot);

  return size;
}

/* Output the virtual call table used to disambiguate PC values when
   identical function have been merged.  */

static void
output_vcall_table (void)
{
  unsigned i;
  unsigned long vcall_length = size_of_vcall_table ();
  vcall_entry *p;
  char poc_label[MAX_ARTIFICIAL_LABEL_BYTES];

  if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
    dw2_asm_output_data (4, 0xffffffff,
      "Initial length escape value indicating 64-bit DWARF extension");
  dw2_asm_output_data (DWARF_OFFSET_SIZE, vcall_length,
                       "Length of Virtual Call Table");
  dw2_asm_output_data (2, 4, "Version number");
  dw2_asm_output_data (1, DWARF2_ADDR_SIZE, "Pointer Size (in bytes)");

  FOR_EACH_VEC_ELT (vcall_entry, vcall_table, i, p)
    {
      ASM_GENERATE_INTERNAL_LABEL (poc_label, "LPOC", p->poc_label_num);
      dw2_asm_output_addr (DWARF_OFFSET_SIZE, poc_label, "Point of call");
      dw2_asm_output_data_uleb128 (p->vtable_slot, "Vtable slot");
    }
}
\f
/* Given a pointer to a tree node for some base type, return a pointer to
   a DIE that describes the given type.

   This routine must only be called for GCC type nodes that correspond to
   Dwarf base (fundamental) types.  */

static dw_die_ref
base_type_die (tree type)
{
  dw_die_ref base_type_result;
  enum dwarf_type encoding;

  if (TREE_CODE (type) == ERROR_MARK || TREE_CODE (type) == VOID_TYPE)
    return 0;

  /* If this is a subtype that should not be emitted as a subrange type,
     use the base type.  See subrange_type_for_debug_p.  */
  if (TREE_CODE (type) == INTEGER_TYPE && TREE_TYPE (type) != NULL_TREE)
    type = TREE_TYPE (type);

  switch (TREE_CODE (type))
    {
    case INTEGER_TYPE:
      if ((dwarf_version >= 4 || !dwarf_strict)
          && TYPE_NAME (type)
          && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
          && DECL_IS_BUILTIN (TYPE_NAME (type))
          && DECL_NAME (TYPE_NAME (type)))
        {
          const char *name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
          if (strcmp (name, "char16_t") == 0
              || strcmp (name, "char32_t") == 0)
            {
              encoding = DW_ATE_UTF;
              break;
            }
        }
      if (TYPE_STRING_FLAG (type))
        {
          if (TYPE_UNSIGNED (type))
            encoding = DW_ATE_unsigned_char;
          else
            encoding = DW_ATE_signed_char;
        }
      else if (TYPE_UNSIGNED (type))
        encoding = DW_ATE_unsigned;
      else
        encoding = DW_ATE_signed;
      break;

    case REAL_TYPE:
      if (DECIMAL_FLOAT_MODE_P (TYPE_MODE (type)))
        {
          if (dwarf_version >= 3 || !dwarf_strict)
            encoding = DW_ATE_decimal_float;
          else
            encoding = DW_ATE_lo_user;
        }
      else
        encoding = DW_ATE_float;
      break;

    case FIXED_POINT_TYPE:
      if (!(dwarf_version >= 3 || !dwarf_strict))
        encoding = DW_ATE_lo_user;
      else if (TYPE_UNSIGNED (type))
        encoding = DW_ATE_unsigned_fixed;
      else
        encoding = DW_ATE_signed_fixed;
      break;

      /* Dwarf2 doesn't know anything about complex ints, so use
         a user defined type for it.  */
    case COMPLEX_TYPE:
      if (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE)
        encoding = DW_ATE_complex_float;
      else
        encoding = DW_ATE_lo_user;
      break;

    case BOOLEAN_TYPE:
      /* GNU FORTRAN/Ada/C++ BOOLEAN type.  */
      encoding = DW_ATE_boolean;
      break;

    default:
      /* No other TREE_CODEs are Dwarf fundamental types.  */
      gcc_unreachable ();
    }

  base_type_result = new_die (DW_TAG_base_type, comp_unit_die (), type);

  add_AT_unsigned (base_type_result, DW_AT_byte_size,
                   int_size_in_bytes (type));
  add_AT_unsigned (base_type_result, DW_AT_encoding, encoding);

  return base_type_result;
}

/* Given a pointer to an arbitrary ..._TYPE tree node, return nonzero if the
   given input type is a Dwarf "fundamental" type.  Otherwise return null.  */

static inline int
is_base_type (tree type)
{
  switch (TREE_CODE (type))
    {
    case ERROR_MARK:
    case VOID_TYPE:
    case INTEGER_TYPE:
    case REAL_TYPE:
    case FIXED_POINT_TYPE:
    case COMPLEX_TYPE:
    case BOOLEAN_TYPE:
      return 1;

    case ARRAY_TYPE:
    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
    case ENUMERAL_TYPE:
    case FUNCTION_TYPE:
    case METHOD_TYPE:
    case POINTER_TYPE:
    case REFERENCE_TYPE:
    case NULLPTR_TYPE:
    case OFFSET_TYPE:
    case LANG_TYPE:
    case VECTOR_TYPE:
      return 0;

    default:
      gcc_unreachable ();
    }

  return 0;
}

/* Given a pointer to a tree node, assumed to be some kind of a ..._TYPE
   node, return the size in bits for the type if it is a constant, or else
   return the alignment for the type if the type's size is not constant, or
   else return BITS_PER_WORD if the type actually turns out to be an
   ERROR_MARK node.  */

static inline unsigned HOST_WIDE_INT
simple_type_size_in_bits (const_tree type)
{
  if (TREE_CODE (type) == ERROR_MARK)
    return BITS_PER_WORD;
  else if (TYPE_SIZE (type) == NULL_TREE)
    return 0;
  else if (host_integerp (TYPE_SIZE (type), 1))
    return tree_low_cst (TYPE_SIZE (type), 1);
  else
    return TYPE_ALIGN (type);
}

/* Similarly, but return a double_int instead of UHWI.  */

static inline double_int
double_int_type_size_in_bits (const_tree type)
{
  if (TREE_CODE (type) == ERROR_MARK)
    return uhwi_to_double_int (BITS_PER_WORD);
  else if (TYPE_SIZE (type) == NULL_TREE)
    return double_int_zero;
  else if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
    return tree_to_double_int (TYPE_SIZE (type));
  else
    return uhwi_to_double_int (TYPE_ALIGN (type));
}

/*  Given a pointer to a tree node for a subrange type, return a pointer
    to a DIE that describes the given type.  */

static dw_die_ref
subrange_type_die (tree type, tree low, tree high, dw_die_ref context_die)
{
  dw_die_ref subrange_die;
  const HOST_WIDE_INT size_in_bytes = int_size_in_bytes (type);

  if (context_die == NULL)
    context_die = comp_unit_die ();

  subrange_die = new_die (DW_TAG_subrange_type, context_die, type);

  if (int_size_in_bytes (TREE_TYPE (type)) != size_in_bytes)
    {
      /* The size of the subrange type and its base type do not match,
         so we need to generate a size attribute for the subrange type.  */
      add_AT_unsigned (subrange_die, DW_AT_byte_size, size_in_bytes);
    }

  if (low)
    add_bound_info (subrange_die, DW_AT_lower_bound, low);
  if (high)
    add_bound_info (subrange_die, DW_AT_upper_bound, high);

  return subrange_die;
}

/* Given a pointer to an arbitrary ..._TYPE tree node, return a debugging
   entry that chains various modifiers in front of the given type.  */

static dw_die_ref
modified_type_die (tree type, int is_const_type, int is_volatile_type,
                   dw_die_ref context_die)
{
  enum tree_code code = TREE_CODE (type);
  dw_die_ref mod_type_die;
  dw_die_ref sub_die = NULL;
  tree item_type = NULL;
  tree qualified_type;
  tree name, low, high;

  if (code == ERROR_MARK)
    return NULL;

  /* See if we already have the appropriately qualified variant of
     this type.  */
  qualified_type
    = get_qualified_type (type,
                          ((is_const_type ? TYPE_QUAL_CONST : 0)
                           | (is_volatile_type ? TYPE_QUAL_VOLATILE : 0)));

  if (qualified_type == sizetype
      && TYPE_NAME (qualified_type)
      && TREE_CODE (TYPE_NAME (qualified_type)) == TYPE_DECL)
    {
      tree t = TREE_TYPE (TYPE_NAME (qualified_type));

      gcc_checking_assert (TREE_CODE (t) == INTEGER_TYPE
                           && TYPE_PRECISION (t)
                           == TYPE_PRECISION (qualified_type)
                           && TYPE_UNSIGNED (t)
                           == TYPE_UNSIGNED (qualified_type));
      qualified_type = t;
    }

  /* If we do, then we can just use its DIE, if it exists.  */
  if (qualified_type)
    {
      mod_type_die = lookup_type_die (qualified_type);
      if (mod_type_die)
        return mod_type_die;
    }

  name = qualified_type ? TYPE_NAME (qualified_type) : NULL;

  /* Handle C typedef types.  */
  if (name && TREE_CODE (name) == TYPE_DECL && DECL_ORIGINAL_TYPE (name)
      && !DECL_ARTIFICIAL (name))
    {
      tree dtype = TREE_TYPE (name);

      if (qualified_type == dtype)
        {
          /* For a named type, use the typedef.  */
          gen_type_die (qualified_type, context_die);
          return lookup_type_die (qualified_type);
        }
      else if (is_const_type < TYPE_READONLY (dtype)
               || is_volatile_type < TYPE_VOLATILE (dtype)
               || (is_const_type <= TYPE_READONLY (dtype)
                   && is_volatile_type <= TYPE_VOLATILE (dtype)
                   && DECL_ORIGINAL_TYPE (name) != type))
        /* cv-unqualified version of named type.  Just use the unnamed
           type to which it refers.  */
        return modified_type_die (DECL_ORIGINAL_TYPE (name),
                                  is_const_type, is_volatile_type,
                                  context_die);
      /* Else cv-qualified version of named type; fall through.  */
    }

  if (is_const_type
      /* If both is_const_type and is_volatile_type, prefer the path
         which leads to a qualified type.  */
      && (!is_volatile_type
          || get_qualified_type (type, TYPE_QUAL_CONST) == NULL_TREE
          || get_qualified_type (type, TYPE_QUAL_VOLATILE) != NULL_TREE))
    {
      mod_type_die = new_die (DW_TAG_const_type, comp_unit_die (), type);
      sub_die = modified_type_die (type, 0, is_volatile_type, context_die);
    }
  else if (is_volatile_type)
    {
      mod_type_die = new_die (DW_TAG_volatile_type, comp_unit_die (), type);
      sub_die = modified_type_die (type, is_const_type, 0, context_die);
    }
  else if (code == POINTER_TYPE)
    {
      mod_type_die = new_die (DW_TAG_pointer_type, comp_unit_die (), type);
      add_AT_unsigned (mod_type_die, DW_AT_byte_size,
                       simple_type_size_in_bits (type) / BITS_PER_UNIT);
      item_type = TREE_TYPE (type);
      if (!ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (item_type)))
        add_AT_unsigned (mod_type_die, DW_AT_address_class,
                         TYPE_ADDR_SPACE (item_type));
    }
  else if (code == REFERENCE_TYPE)
    {
      if (TYPE_REF_IS_RVALUE (type) && dwarf_version >= 4)
        mod_type_die = new_die (DW_TAG_rvalue_reference_type, comp_unit_die (),
                                type);
      else
        mod_type_die = new_die (DW_TAG_reference_type, comp_unit_die (), type);
      add_AT_unsigned (mod_type_die, DW_AT_byte_size,
                       simple_type_size_in_bits (type) / BITS_PER_UNIT);
      item_type = TREE_TYPE (type);
      if (!ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (item_type)))
        add_AT_unsigned (mod_type_die, DW_AT_address_class,
                         TYPE_ADDR_SPACE (item_type));
    }
  else if (code == INTEGER_TYPE
           && TREE_TYPE (type) != NULL_TREE
           && subrange_type_for_debug_p (type, &low, &high))
    {
      mod_type_die = subrange_type_die (type, low, high, context_die);
      item_type = TREE_TYPE (type);
    }
  else if (is_base_type (type))
    mod_type_die = base_type_die (type);
  else
    {
      gen_type_die (type, context_die);

      /* We have to get the type_main_variant here (and pass that to the
         `lookup_type_die' routine) because the ..._TYPE node we have
         might simply be a *copy* of some original type node (where the
         copy was created to help us keep track of typedef names) and
         that copy might have a different TYPE_UID from the original
         ..._TYPE node.  */
      if (TREE_CODE (type) != VECTOR_TYPE)
        return lookup_type_die (type_main_variant (type));
      else
        /* Vectors have the debugging information in the type,
           not the main variant.  */
        return lookup_type_die (type);
    }

  /* Builtin types don't have a DECL_ORIGINAL_TYPE.  For those,
     don't output a DW_TAG_typedef, since there isn't one in the
     user's program; just attach a DW_AT_name to the type.
     Don't attach a DW_AT_name to DW_TAG_const_type or DW_TAG_volatile_type
     if the base type already has the same name.  */
  if (name
      && ((TREE_CODE (name) != TYPE_DECL
           && (qualified_type == TYPE_MAIN_VARIANT (type)
               || (!is_const_type && !is_volatile_type)))
          || (TREE_CODE (name) == TYPE_DECL
              && TREE_TYPE (name) == qualified_type
              && DECL_NAME (name))))
    {
      if (TREE_CODE (name) == TYPE_DECL)
        /* Could just call add_name_and_src_coords_attributes here,
           but since this is a builtin type it doesn't have any
           useful source coordinates anyway.  */
        name = DECL_NAME (name);
      add_name_attribute (mod_type_die, IDENTIFIER_POINTER (name));
    }
  /* This probably indicates a bug.  */
  else if (mod_type_die && mod_type_die->die_tag == DW_TAG_base_type)
    add_name_attribute (mod_type_die, "__unknown__");

  if (qualified_type)
    equate_type_number_to_die (qualified_type, mod_type_die);

  if (item_type)
    /* We must do this after the equate_type_number_to_die call, in case
       this is a recursive type.  This ensures that the modified_type_die
       recursion will terminate even if the type is recursive.  Recursive
       types are possible in Ada.  */
    sub_die = modified_type_die (item_type,
                                 TYPE_READONLY (item_type),
                                 TYPE_VOLATILE (item_type),
                                 context_die);

  if (sub_die != NULL)
    add_AT_die_ref (mod_type_die, DW_AT_type, sub_die);

  return mod_type_die;
}

/* Generate DIEs for the generic parameters of T.
   T must be either a generic type or a generic function.
   See http://gcc.gnu.org/wiki/TemplateParmsDwarf for more.  */

static void
gen_generic_params_dies (tree t)
{
  tree parms, args;
  int parms_num, i;
  dw_die_ref die = NULL;

  if (!t || (TYPE_P (t) && !COMPLETE_TYPE_P (t)))
    return;

  if (TYPE_P (t))
    die = lookup_type_die (t);
  else if (DECL_P (t))
    die = lookup_decl_die (t);

  gcc_assert (die);

  parms = lang_hooks.get_innermost_generic_parms (t);
  if (!parms)
    /* T has no generic parameter. It means T is neither a generic type
       or function. End of story.  */
    return;

  parms_num = TREE_VEC_LENGTH (parms);
  args = lang_hooks.get_innermost_generic_args (t);
  for (i = 0; i < parms_num; i++)
    {
      tree parm, arg, arg_pack_elems;

      parm = TREE_VEC_ELT (parms, i);
      arg = TREE_VEC_ELT (args, i);
      arg_pack_elems = lang_hooks.types.get_argument_pack_elems (arg);
      gcc_assert (parm && TREE_VALUE (parm) && arg);

      if (parm && TREE_VALUE (parm) && arg)
        {
          /* If PARM represents a template parameter pack,
             emit a DW_TAG_GNU_template_parameter_pack DIE, followed
             by DW_TAG_template_*_parameter DIEs for the argument
             pack elements of ARG. Note that ARG would then be
             an argument pack.  */
          if (arg_pack_elems)
            template_parameter_pack_die (TREE_VALUE (parm),
                                         arg_pack_elems,
                                         die);
          else
            generic_parameter_die (TREE_VALUE (parm), arg,
                                   true /* Emit DW_AT_name */, die);
        }
    }
}

/* Create and return a DIE for PARM which should be
   the representation of a generic type parameter.
   For instance, in the C++ front end, PARM would be a template parameter.
   ARG is the argument to PARM.
   EMIT_NAME_P if tree, the DIE will have DW_AT_name attribute set to the
   name of the PARM.
   PARENT_DIE is the parent DIE which the new created DIE should be added to,
   as a child node.  */

static dw_die_ref
generic_parameter_die (tree parm, tree arg,
                       bool emit_name_p,
                       dw_die_ref parent_die)
{
  dw_die_ref tmpl_die = NULL;
  const char *name = NULL;

  if (!parm || !DECL_NAME (parm) || !arg)
    return NULL;

  /* We support non-type generic parameters and arguments,
     type generic parameters and arguments, as well as
     generic generic parameters (a.k.a. template template parameters in C++)
     and arguments.  */
  if (TREE_CODE (parm) == PARM_DECL)
    /* PARM is a nontype generic parameter  */
    tmpl_die = new_die (DW_TAG_template_value_param, parent_die, parm);
  else if (TREE_CODE (parm) == TYPE_DECL)
    /* PARM is a type generic parameter.  */
    tmpl_die = new_die (DW_TAG_template_type_param, parent_die, parm);
  else if (lang_hooks.decls.generic_generic_parameter_decl_p (parm))
    /* PARM is a generic generic parameter.
       Its DIE is a GNU extension. It shall have a
       DW_AT_name attribute to represent the name of the template template
       parameter, and a DW_AT_GNU_template_name attribute to represent the
       name of the template template argument.  */
    tmpl_die = new_die (DW_TAG_GNU_template_template_param,
                        parent_die, parm);
  else
    gcc_unreachable ();

  if (tmpl_die)
    {
      tree tmpl_type;

      /* If PARM is a generic parameter pack, it means we are
         emitting debug info for a template argument pack element.
         In other terms, ARG is a template argument pack element.
         In that case, we don't emit any DW_AT_name attribute for
         the die.  */
      if (emit_name_p)
        {
          name = IDENTIFIER_POINTER (DECL_NAME (parm));
          gcc_assert (name);
          add_AT_string (tmpl_die, DW_AT_name, name);
        }

      if (!lang_hooks.decls.generic_generic_parameter_decl_p (parm))
        {
          /* DWARF3, 5.6.8 says if PARM is a non-type generic parameter
             TMPL_DIE should have a child DW_AT_type attribute that is set
             to the type of the argument to PARM, which is ARG.
             If PARM is a type generic parameter, TMPL_DIE should have a
             child DW_AT_type that is set to ARG.  */
          tmpl_type = TYPE_P (arg) ? arg : TREE_TYPE (arg);
          add_type_attribute (tmpl_die, tmpl_type, 0,
                              TREE_THIS_VOLATILE (tmpl_type),
                              parent_die);
        }
      else
        {
          /* So TMPL_DIE is a DIE representing a
             a generic generic template parameter, a.k.a template template
             parameter in C++ and arg is a template.  */

          /* The DW_AT_GNU_template_name attribute of the DIE must be set
             to the name of the argument.  */
          name = dwarf2_name (TYPE_P (arg) ? TYPE_NAME (arg) : arg, 1);
          if (name)
            add_AT_string (tmpl_die, DW_AT_GNU_template_name, name);
        }

      if (TREE_CODE (parm) == PARM_DECL)
        /* So PARM is a non-type generic parameter.
           DWARF3 5.6.8 says we must set a DW_AT_const_value child
           attribute of TMPL_DIE which value represents the value
           of ARG.
           We must be careful here:
           The value of ARG might reference some function decls.
           We might currently be emitting debug info for a generic
           type and types are emitted before function decls, we don't
           know if the function decls referenced by ARG will actually be
           emitted after cgraph computations.
           So must defer the generation of the DW_AT_const_value to
           after cgraph is ready.  */
        append_entry_to_tmpl_value_parm_die_table (tmpl_die, arg);
    }

  return tmpl_die;
}

/* Generate and return a  DW_TAG_GNU_template_parameter_pack DIE representing.
   PARM_PACK must be a template parameter pack. The returned DIE
   will be child DIE of PARENT_DIE.  */

static dw_die_ref
template_parameter_pack_die (tree parm_pack,
                             tree parm_pack_args,
                             dw_die_ref parent_die)
{
  dw_die_ref die;
  int j;

  gcc_assert (parent_die && parm_pack);

  die = new_die (DW_TAG_GNU_template_parameter_pack, parent_die, parm_pack);
  add_name_and_src_coords_attributes (die, parm_pack);
  for (j = 0; j < TREE_VEC_LENGTH (parm_pack_args); j++)
    generic_parameter_die (parm_pack,
                           TREE_VEC_ELT (parm_pack_args, j),
                           false /* Don't emit DW_AT_name */,
                           die);
  return die;
}

/* Given a pointer to an arbitrary ..._TYPE tree node, return true if it is
   an enumerated type.  */

static inline int
type_is_enum (const_tree type)
{
  return TREE_CODE (type) == ENUMERAL_TYPE;
}

/* Return the DBX register number described by a given RTL node.  */

static unsigned int
dbx_reg_number (const_rtx rtl)
{
  unsigned regno = REGNO (rtl);

  gcc_assert (regno < FIRST_PSEUDO_REGISTER);

#ifdef LEAF_REG_REMAP
  if (current_function_uses_only_leaf_regs)
    {
      int leaf_reg = LEAF_REG_REMAP (regno);
      if (leaf_reg != -1)
        regno = (unsigned) leaf_reg;
    }
#endif

  return DBX_REGISTER_NUMBER (regno);
}

/* Optionally add a DW_OP_piece term to a location description expression.
   DW_OP_piece is only added if the location description expression already
   doesn't end with DW_OP_piece.  */

static void
add_loc_descr_op_piece (dw_loc_descr_ref *list_head, int size)
{
  dw_loc_descr_ref loc;

  if (*list_head != NULL)
    {
      /* Find the end of the chain.  */
      for (loc = *list_head; loc->dw_loc_next != NULL; loc = loc->dw_loc_next)
        ;

      if (loc->dw_loc_opc != DW_OP_piece)
        loc->dw_loc_next = new_loc_descr (DW_OP_piece, size, 0);
    }
}

/* Return a location descriptor that designates a machine register or
   zero if there is none.  */

static dw_loc_descr_ref
reg_loc_descriptor (rtx rtl, enum var_init_status initialized)
{
  rtx regs;

  if (REGNO (rtl) >= FIRST_PSEUDO_REGISTER)
    return 0;

  /* We only use "frame base" when we're sure we're talking about the
     post-prologue local stack frame.  We do this by *not* running
     register elimination until this point, and recognizing the special
     argument pointer and soft frame pointer rtx's.
     Use DW_OP_fbreg offset DW_OP_stack_value in this case.  */
  if ((rtl == arg_pointer_rtx || rtl == frame_pointer_rtx)
      && eliminate_regs (rtl, VOIDmode, NULL_RTX) != rtl)
    {
      dw_loc_descr_ref result = NULL;

      if (dwarf_version >= 4 || !dwarf_strict)
        {
          result = mem_loc_descriptor (rtl, VOIDmode, initialized);
          if (result)
            add_loc_descr (&result,
                           new_loc_descr (DW_OP_stack_value, 0, 0));
        }
      return result;
    }

  regs = targetm.dwarf_register_span (rtl);

  if (hard_regno_nregs[REGNO (rtl)][GET_MODE (rtl)] > 1 || regs)
    return multiple_reg_loc_descriptor (rtl, regs, initialized);
  else
    return one_reg_loc_descriptor (dbx_reg_number (rtl), initialized);
}

/* Return a location descriptor that designates a machine register for
   a given hard register number.  */

static dw_loc_descr_ref
one_reg_loc_descriptor (unsigned int regno, enum var_init_status initialized)
{
  dw_loc_descr_ref reg_loc_descr;

  if (regno <= 31)
    reg_loc_descr
      = new_loc_descr ((enum dwarf_location_atom) (DW_OP_reg0 + regno), 0, 0);
  else
    reg_loc_descr = new_loc_descr (DW_OP_regx, regno, 0);

  if (initialized == VAR_INIT_STATUS_UNINITIALIZED)
    add_loc_descr (&reg_loc_descr, new_loc_descr (DW_OP_GNU_uninit, 0, 0));

  return reg_loc_descr;
}

/* Given an RTL of a register, return a location descriptor that
   designates a value that spans more than one register.  */

static dw_loc_descr_ref
multiple_reg_loc_descriptor (rtx rtl, rtx regs,
                             enum var_init_status initialized)
{
  int nregs, size, i;
  unsigned reg;
  dw_loc_descr_ref loc_result = NULL;

  reg = REGNO (rtl);
#ifdef LEAF_REG_REMAP
  if (current_function_uses_only_leaf_regs)
    {
      int leaf_reg = LEAF_REG_REMAP (reg);
      if (leaf_reg != -1)
        reg = (unsigned) leaf_reg;
    }
#endif
  gcc_assert ((unsigned) DBX_REGISTER_NUMBER (reg) == dbx_reg_number (rtl));
  nregs = hard_regno_nregs[REGNO (rtl)][GET_MODE (rtl)];

  /* Simple, contiguous registers.  */
  if (regs == NULL_RTX)
    {
      size = GET_MODE_SIZE (GET_MODE (rtl)) / nregs;

      loc_result = NULL;
      while (nregs--)
        {
          dw_loc_descr_ref t;

          t = one_reg_loc_descriptor (DBX_REGISTER_NUMBER (reg),
                                      VAR_INIT_STATUS_INITIALIZED);
          add_loc_descr (&loc_result, t);
          add_loc_descr_op_piece (&loc_result, size);
          ++reg;
        }
      return loc_result;
    }

  /* Now onto stupid register sets in non contiguous locations.  */

  gcc_assert (GET_CODE (regs) == PARALLEL);

  size = GET_MODE_SIZE (GET_MODE (XVECEXP (regs, 0, 0)));
  loc_result = NULL;

  for (i = 0; i < XVECLEN (regs, 0); ++i)
    {
      dw_loc_descr_ref t;

      t = one_reg_loc_descriptor (REGNO (XVECEXP (regs, 0, i)),
                                  VAR_INIT_STATUS_INITIALIZED);
      add_loc_descr (&loc_result, t);
      size = GET_MODE_SIZE (GET_MODE (XVECEXP (regs, 0, 0)));
      add_loc_descr_op_piece (&loc_result, size);
    }

  if (loc_result && initialized == VAR_INIT_STATUS_UNINITIALIZED)
    add_loc_descr (&loc_result, new_loc_descr (DW_OP_GNU_uninit, 0, 0));
  return loc_result;
}

/* Return a location descriptor that designates a constant.  */

static dw_loc_descr_ref
int_loc_descriptor (HOST_WIDE_INT i)
{
  enum dwarf_location_atom op;

  /* Pick the smallest representation of a constant, rather than just
     defaulting to the LEB encoding.  */
  if (i >= 0)
    {
      if (i <= 31)
        op = (enum dwarf_location_atom) (DW_OP_lit0 + i);
      else if (i <= 0xff)
        op = DW_OP_const1u;
      else if (i <= 0xffff)
        op = DW_OP_const2u;
      else if (HOST_BITS_PER_WIDE_INT == 32
               || i <= 0xffffffff)
        op = DW_OP_const4u;
      else
        op = DW_OP_constu;
    }
  else
    {
      if (i >= -0x80)
        op = DW_OP_const1s;
      else if (i >= -0x8000)
        op = DW_OP_const2s;
      else if (HOST_BITS_PER_WIDE_INT == 32
               || i >= -0x80000000)
        op = DW_OP_const4s;
      else
        op = DW_OP_consts;
    }

  return new_loc_descr (op, i, 0);
}

/* Return loc description representing "address" of integer value.
   This can appear only as toplevel expression.  */

static dw_loc_descr_ref
address_of_int_loc_descriptor (int size, HOST_WIDE_INT i)
{
  int litsize;
  dw_loc_descr_ref loc_result = NULL;

  if (!(dwarf_version >= 4 || !dwarf_strict))
    return NULL;

  if (i >= 0)
    {
      if (i <= 31)
        litsize = 1;
      else if (i <= 0xff)
        litsize = 2;
      else if (i <= 0xffff)
        litsize = 3;
      else if (HOST_BITS_PER_WIDE_INT == 32
               || i <= 0xffffffff)
        litsize = 5;
      else
        litsize = 1 + size_of_uleb128 ((unsigned HOST_WIDE_INT) i);
    }
  else
    {
      if (i >= -0x80)
        litsize = 2;
      else if (i >= -0x8000)
        litsize = 3;
      else if (HOST_BITS_PER_WIDE_INT == 32
               || i >= -0x80000000)
        litsize = 5;
      else
        litsize = 1 + size_of_sleb128 (i);
    }
  /* Determine if DW_OP_stack_value or DW_OP_implicit_value
     is more compact.  For DW_OP_stack_value we need:
     litsize + 1 (DW_OP_stack_value)
     and for DW_OP_implicit_value:
     1 (DW_OP_implicit_value) + 1 (length) + size.  */
  if ((int) DWARF2_ADDR_SIZE >= size && litsize + 1 <= 1 + 1 + size)
    {
      loc_result = int_loc_descriptor (i);
      add_loc_descr (&loc_result,
                     new_loc_descr (DW_OP_stack_value, 0, 0));
      return loc_result;
    }

  loc_result = new_loc_descr (DW_OP_implicit_value,
                              size, 0);
  loc_result->dw_loc_oprnd2.val_class = dw_val_class_const;
  loc_result->dw_loc_oprnd2.v.val_int = i;
  return loc_result;
}

/* Return a location descriptor that designates a base+offset location.  */

static dw_loc_descr_ref
based_loc_descr (rtx reg, HOST_WIDE_INT offset,
                 enum var_init_status initialized)
{
  unsigned int regno;
  dw_loc_descr_ref result;
  dw_fde_ref fde = current_fde ();

  /* We only use "frame base" when we're sure we're talking about the
     post-prologue local stack frame.  We do this by *not* running
     register elimination until this point, and recognizing the special
     argument pointer and soft frame pointer rtx's.  */
  if (reg == arg_pointer_rtx || reg == frame_pointer_rtx)
    {
      rtx elim = eliminate_regs (reg, VOIDmode, NULL_RTX);

      if (elim != reg)
        {
          if (GET_CODE (elim) == PLUS)
            {
              offset += INTVAL (XEXP (elim, 1));
              elim = XEXP (elim, 0);
            }
          gcc_assert ((SUPPORTS_STACK_ALIGNMENT
                       && (elim == hard_frame_pointer_rtx
                           || elim == stack_pointer_rtx))
                      || elim == (frame_pointer_needed
                                  ? hard_frame_pointer_rtx
                                  : stack_pointer_rtx));

          /* If drap register is used to align stack, use frame
             pointer + offset to access stack variables.  If stack
             is aligned without drap, use stack pointer + offset to
             access stack variables.  */
          if (crtl->stack_realign_tried
              && reg == frame_pointer_rtx)
            {
              int base_reg
                = DWARF_FRAME_REGNUM ((fde && fde->drap_reg != INVALID_REGNUM)
                                      ? HARD_FRAME_POINTER_REGNUM
                                      : STACK_POINTER_REGNUM);
              return new_reg_loc_descr (base_reg, offset);
            }

          offset += frame_pointer_fb_offset;
          return new_loc_descr (DW_OP_fbreg, offset, 0);
        }
    }
  else if (!optimize
           && fde
           && (fde->drap_reg == REGNO (reg)
               || fde->vdrap_reg == REGNO (reg)))
    {
      /* Use cfa+offset to represent the location of arguments passed
         on the stack when drap is used to align stack.
         Only do this when not optimizing, for optimized code var-tracking
         is supposed to track where the arguments live and the register
         used as vdrap or drap in some spot might be used for something
         else in other part of the routine.  */
      return new_loc_descr (DW_OP_fbreg, offset, 0);
    }

  regno = dbx_reg_number (reg);
  if (regno <= 31)
    result = new_loc_descr ((enum dwarf_location_atom) (DW_OP_breg0 + regno),
                            offset, 0);
  else
    result = new_loc_descr (DW_OP_bregx, regno, offset);

  if (initialized == VAR_INIT_STATUS_UNINITIALIZED)
    add_loc_descr (&result, new_loc_descr (DW_OP_GNU_uninit, 0, 0));

  return result;
}

/* Return true if this RTL expression describes a base+offset calculation.  */

static inline int
is_based_loc (const_rtx rtl)
{
  return (GET_CODE (rtl) == PLUS
          && ((REG_P (XEXP (rtl, 0))
               && REGNO (XEXP (rtl, 0)) < FIRST_PSEUDO_REGISTER
               && CONST_INT_P (XEXP (rtl, 1)))));
}

/* Try to handle TLS MEMs, for which mem_loc_descriptor on XEXP (mem, 0)
   failed.  */

static dw_loc_descr_ref
tls_mem_loc_descriptor (rtx mem)
{
  tree base;
  dw_loc_descr_ref loc_result;

  if (MEM_EXPR (mem) == NULL_TREE || MEM_OFFSET (mem) == NULL_RTX)
    return NULL;

  base = get_base_address (MEM_EXPR (mem));
  if (base == NULL
      || TREE_CODE (base) != VAR_DECL
      || !DECL_THREAD_LOCAL_P (base))
    return NULL;

  loc_result = loc_descriptor_from_tree (MEM_EXPR (mem), 1);
  if (loc_result == NULL)
    return NULL;

  if (INTVAL (MEM_OFFSET (mem)))
    loc_descr_plus_const (&loc_result, INTVAL (MEM_OFFSET (mem)));

  return loc_result;
}

/* Output debug info about reason why we failed to expand expression as dwarf
   expression.  */

static void
expansion_failed (tree expr, rtx rtl, char const *reason)
{
  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "Failed to expand as dwarf: ");
      if (expr)
        print_generic_expr (dump_file, expr, dump_flags);
      if (rtl)
        {
          fprintf (dump_file, "\n");
          print_rtl (dump_file, rtl);
        }
      fprintf (dump_file, "\nReason: %s\n", reason);
    }
}

/* Helper function for const_ok_for_output, called either directly
   or via for_each_rtx.  */

static int
const_ok_for_output_1 (rtx *rtlp, void *data ATTRIBUTE_UNUSED)
{
  rtx rtl = *rtlp;

  if (GET_CODE (rtl) == UNSPEC)
    {
      /* If delegitimize_address couldn't do anything with the UNSPEC, assume
         we can't express it in the debug info.  */
#ifdef ENABLE_CHECKING
      /* Don't complain about TLS UNSPECs, those are just too hard to
         delegitimize.  */
      if (XVECLEN (rtl, 0) != 1
          || GET_CODE (XVECEXP (rtl, 0, 0)) != SYMBOL_REF
          || SYMBOL_REF_DECL (XVECEXP (rtl, 0, 0)) == NULL
          || TREE_CODE (SYMBOL_REF_DECL (XVECEXP (rtl, 0, 0))) != VAR_DECL
          || !DECL_THREAD_LOCAL_P (SYMBOL_REF_DECL (XVECEXP (rtl, 0, 0))))
        inform (current_function_decl
                ? DECL_SOURCE_LOCATION (current_function_decl)
                : UNKNOWN_LOCATION,
                "non-delegitimized UNSPEC %d found in variable location",
                XINT (rtl, 1));
#endif
      expansion_failed (NULL_TREE, rtl,
                        "UNSPEC hasn't been delegitimized.\n");
      return 1;
    }

  if (GET_CODE (rtl) != SYMBOL_REF)
    return 0;

  if (CONSTANT_POOL_ADDRESS_P (rtl))
    {
      bool marked;
      get_pool_constant_mark (rtl, &marked);
      /* If all references to this pool constant were optimized away,
         it was not output and thus we can't represent it.  */
      if (!marked)
        {
          expansion_failed (NULL_TREE, rtl,
                            "Constant was removed from constant pool.\n");
          return 1;
        }
    }

  if (SYMBOL_REF_TLS_MODEL (rtl) != TLS_MODEL_NONE)
    return 1;

  /* Avoid references to external symbols in debug info, on several targets
     the linker might even refuse to link when linking a shared library,
     and in many other cases the relocations for .debug_info/.debug_loc are
     dropped, so the address becomes zero anyway.  Hidden symbols, guaranteed
     to be defined within the same shared library or executable are fine.  */
  if (SYMBOL_REF_EXTERNAL_P (rtl))
    {
      tree decl = SYMBOL_REF_DECL (rtl);

      if (decl == NULL || !targetm.binds_local_p (decl))
        {
          expansion_failed (NULL_TREE, rtl,
                            "Symbol not defined in current TU.\n");
          return 1;
        }
    }

  return 0;
}

/* Return true if constant RTL can be emitted in DW_OP_addr or
   DW_AT_const_value.  TLS SYMBOL_REFs, external SYMBOL_REFs or
   non-marked constant pool SYMBOL_REFs can't be referenced in it.  */

static bool
const_ok_for_output (rtx rtl)
{
  if (GET_CODE (rtl) == SYMBOL_REF)
    return const_ok_for_output_1 (&rtl, NULL) == 0;

  if (GET_CODE (rtl) == CONST)
    return for_each_rtx (&XEXP (rtl, 0), const_ok_for_output_1, NULL) == 0;

  return true;
}

/* The following routine converts the RTL for a variable or parameter
   (resident in memory) into an equivalent Dwarf representation of a
   mechanism for getting the address of that same variable onto the top of a
   hypothetical "address evaluation" stack.

   When creating memory location descriptors, we are effectively transforming
   the RTL for a memory-resident object into its Dwarf postfix expression
   equivalent.  This routine recursively descends an RTL tree, turning
   it into Dwarf postfix code as it goes.

   MODE is the mode of the memory reference, needed to handle some
   autoincrement addressing modes.

   CAN_USE_FBREG is a flag whether we can use DW_AT_frame_base in the
   location list for RTL.

   Return 0 if we can't represent the location.  */

static dw_loc_descr_ref
mem_loc_descriptor (rtx rtl, enum machine_mode mode,
                    enum var_init_status initialized)
{
  dw_loc_descr_ref mem_loc_result = NULL;
  enum dwarf_location_atom op;
  dw_loc_descr_ref op0, op1;

  /* Note that for a dynamically sized array, the location we will generate a
     description of here will be the lowest numbered location which is
     actually within the array.  That's *not* necessarily the same as the
     zeroth element of the array.  */

  rtl = targetm.delegitimize_address (rtl);

  switch (GET_CODE (rtl))
    {
    case POST_INC:
    case POST_DEC:
    case POST_MODIFY:
      return mem_loc_descriptor (XEXP (rtl, 0), mode, initialized);

    case SUBREG:
      /* The case of a subreg may arise when we have a local (register)
         variable or a formal (register) parameter which doesn't quite fill
         up an entire register.  For now, just assume that it is
         legitimate to make the Dwarf info refer to the whole register which
         contains the given subreg.  */
      if (!subreg_lowpart_p (rtl))
        break;
      rtl = SUBREG_REG (rtl);
      if (GET_MODE_SIZE (GET_MODE (rtl)) > DWARF2_ADDR_SIZE)
        break;
      if (GET_MODE_CLASS (GET_MODE (rtl)) != MODE_INT)
        break;
      mem_loc_result = mem_loc_descriptor (rtl, mode, initialized);
      break;

    case REG:
      /* Whenever a register number forms a part of the description of the
         method for calculating the (dynamic) address of a memory resident
         object, DWARF rules require the register number be referred to as
         a "base register".  This distinction is not based in any way upon
         what category of register the hardware believes the given register
         belongs to.  This is strictly DWARF terminology we're dealing with
         here. Note that in cases where the location of a memory-resident
         data object could be expressed as: OP_ADD (OP_BASEREG (basereg),
         OP_CONST (0)) the actual DWARF location descriptor that we generate
         may just be OP_BASEREG (basereg).  This may look deceptively like
         the object in question was allocated to a register (rather than in
         memory) so DWARF consumers need to be aware of the subtle
         distinction between OP_REG and OP_BASEREG.  */
      if (REGNO (rtl) < FIRST_PSEUDO_REGISTER)
        mem_loc_result = based_loc_descr (rtl, 0, VAR_INIT_STATUS_INITIALIZED);
      else if (stack_realign_drap
               && crtl->drap_reg
               && crtl->args.internal_arg_pointer == rtl
               && REGNO (crtl->drap_reg) < FIRST_PSEUDO_REGISTER)
        {
          /* If RTL is internal_arg_pointer, which has been optimized
             out, use DRAP instead.  */
          mem_loc_result = based_loc_descr (crtl->drap_reg, 0,
                                            VAR_INIT_STATUS_INITIALIZED);
        }
      break;

    case SIGN_EXTEND:
    case ZERO_EXTEND:
      op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                VAR_INIT_STATUS_INITIALIZED);
      if (op0 == 0)
        break;
      else
        {
          int shift = DWARF2_ADDR_SIZE
                      - GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0)));
          shift *= BITS_PER_UNIT;
          if (GET_CODE (rtl) == SIGN_EXTEND)
            op = DW_OP_shra;
          else
            op = DW_OP_shr;
          mem_loc_result = op0;
          add_loc_descr (&mem_loc_result, int_loc_descriptor (shift));
          add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_shl, 0, 0));
          add_loc_descr (&mem_loc_result, int_loc_descriptor (shift));
          add_loc_descr (&mem_loc_result, new_loc_descr (op, 0, 0));
        }
      break;

    case MEM:
      mem_loc_result = mem_loc_descriptor (XEXP (rtl, 0), GET_MODE (rtl),
                                           VAR_INIT_STATUS_INITIALIZED);
      if (mem_loc_result == NULL)
        mem_loc_result = tls_mem_loc_descriptor (rtl);
      if (mem_loc_result != 0)
        {
          if (GET_MODE_SIZE (GET_MODE (rtl)) > DWARF2_ADDR_SIZE)
            {
              expansion_failed (NULL_TREE, rtl, "DWARF address size mismatch");
              return 0;
            }
          else if (GET_MODE_SIZE (GET_MODE (rtl)) == DWARF2_ADDR_SIZE)
            add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_deref, 0, 0));
          else
            add_loc_descr (&mem_loc_result,
                           new_loc_descr (DW_OP_deref_size,
                                          GET_MODE_SIZE (GET_MODE (rtl)), 0));
        }
      else
        {
          rtx new_rtl = avoid_constant_pool_reference (rtl);
          if (new_rtl != rtl)
            return mem_loc_descriptor (new_rtl, mode, initialized);
        }
      break;

    case LO_SUM:
         rtl = XEXP (rtl, 1);

      /* ... fall through ...  */

    case LABEL_REF:
      /* Some ports can transform a symbol ref into a label ref, because
         the symbol ref is too far away and has to be dumped into a constant
         pool.  */
    case CONST:
    case SYMBOL_REF:
      if (GET_CODE (rtl) == SYMBOL_REF
          && SYMBOL_REF_TLS_MODEL (rtl) != TLS_MODEL_NONE)
        {
          dw_loc_descr_ref temp;

          /* If this is not defined, we have no way to emit the data.  */
          if (!targetm.have_tls || !targetm.asm_out.output_dwarf_dtprel)
            break;

          /* We used to emit DW_OP_addr here, but that's wrong, since
             DW_OP_addr should be relocated by the debug info consumer,
             while DW_OP_GNU_push_tls_address operand should not.  */
          temp = new_loc_descr (DWARF2_ADDR_SIZE == 4
                                ? DW_OP_const4u : DW_OP_const8u, 0, 0);
          temp->dw_loc_oprnd1.val_class = dw_val_class_addr;
          temp->dw_loc_oprnd1.v.val_addr = rtl;
          temp->dtprel = true;

          mem_loc_result = new_loc_descr (DW_OP_GNU_push_tls_address, 0, 0);
          add_loc_descr (&mem_loc_result, temp);

          break;
        }

      if (!const_ok_for_output (rtl))
        break;

    symref:
      mem_loc_result = new_loc_descr (DW_OP_addr, 0, 0);
      mem_loc_result->dw_loc_oprnd1.val_class = dw_val_class_addr;
      mem_loc_result->dw_loc_oprnd1.v.val_addr = rtl;
      VEC_safe_push (rtx, gc, used_rtx_array, rtl);
      break;

    case CONCAT:
    case CONCATN:
    case VAR_LOCATION:
    case DEBUG_IMPLICIT_PTR:
      expansion_failed (NULL_TREE, rtl,
                        "CONCAT/CONCATN/VAR_LOCATION is handled only by loc_descriptor");
      return 0;

    case PRE_MODIFY:
      /* Extract the PLUS expression nested inside and fall into
         PLUS code below.  */
      rtl = XEXP (rtl, 1);
      goto plus;

    case PRE_INC:
    case PRE_DEC:
      /* Turn these into a PLUS expression and fall into the PLUS code
         below.  */
      rtl = gen_rtx_PLUS (word_mode, XEXP (rtl, 0),
                          GEN_INT (GET_CODE (rtl) == PRE_INC
                                   ? GET_MODE_UNIT_SIZE (mode)
                                   : -GET_MODE_UNIT_SIZE (mode)));

      /* ... fall through ...  */

    case PLUS:
    plus:
      if (is_based_loc (rtl))
        mem_loc_result = based_loc_descr (XEXP (rtl, 0),
                                          INTVAL (XEXP (rtl, 1)),
                                          VAR_INIT_STATUS_INITIALIZED);
      else
        {
          mem_loc_result = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                               VAR_INIT_STATUS_INITIALIZED);
          if (mem_loc_result == 0)
            break;

          if (CONST_INT_P (XEXP (rtl, 1)))
            loc_descr_plus_const (&mem_loc_result, INTVAL (XEXP (rtl, 1)));
          else
            {
              dw_loc_descr_ref mem_loc_result2
                = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                      VAR_INIT_STATUS_INITIALIZED);
              if (mem_loc_result2 == 0)
                break;
              add_loc_descr (&mem_loc_result, mem_loc_result2);
              add_loc_descr (&mem_loc_result,
                             new_loc_descr (DW_OP_plus, 0, 0));
            }
        }
      break;

    /* If a pseudo-reg is optimized away, it is possible for it to
       be replaced with a MEM containing a multiply or shift.  */
    case MINUS:
      op = DW_OP_minus;
      goto do_binop;

    case MULT:
      op = DW_OP_mul;
      goto do_binop;

    case DIV:
      op = DW_OP_div;
      goto do_binop;

    case UMOD:
      op = DW_OP_mod;
      goto do_binop;

    case ASHIFT:
      op = DW_OP_shl;
      goto do_binop;

    case ASHIFTRT:
      op = DW_OP_shra;
      goto do_binop;

    case LSHIFTRT:
      op = DW_OP_shr;
      goto do_binop;

    case AND:
      op = DW_OP_and;
      goto do_binop;

    case IOR:
      op = DW_OP_or;
      goto do_binop;

    case XOR:
      op = DW_OP_xor;
      goto do_binop;

    do_binop:
      op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                VAR_INIT_STATUS_INITIALIZED);
      op1 = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                VAR_INIT_STATUS_INITIALIZED);

      if (op0 == 0 || op1 == 0)
        break;

      mem_loc_result = op0;
      add_loc_descr (&mem_loc_result, op1);
      add_loc_descr (&mem_loc_result, new_loc_descr (op, 0, 0));
      break;

    case MOD:
      op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                VAR_INIT_STATUS_INITIALIZED);
      op1 = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                VAR_INIT_STATUS_INITIALIZED);

      if (op0 == 0 || op1 == 0)
        break;

      mem_loc_result = op0;
      add_loc_descr (&mem_loc_result, op1);
      add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_over, 0, 0));
      add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_over, 0, 0));
      add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_div, 0, 0));
      add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_mul, 0, 0));
      add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_minus, 0, 0));
      break;

    case NOT:
      op = DW_OP_not;
      goto do_unop;

    case ABS:
      op = DW_OP_abs;
      goto do_unop;

    case NEG:
      op = DW_OP_neg;
      goto do_unop;

    do_unop:
      op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                VAR_INIT_STATUS_INITIALIZED);

      if (op0 == 0)
        break;

      mem_loc_result = op0;
      add_loc_descr (&mem_loc_result, new_loc_descr (op, 0, 0));
      break;

    case CONST_INT:
      mem_loc_result = int_loc_descriptor (INTVAL (rtl));
      break;

    case EQ:
      op = DW_OP_eq;
      goto do_scompare;

    case GE:
      op = DW_OP_ge;
      goto do_scompare;

    case GT:
      op = DW_OP_gt;
      goto do_scompare;

    case LE:
      op = DW_OP_le;
      goto do_scompare;

    case LT:
      op = DW_OP_lt;
      goto do_scompare;

    case NE:
      op = DW_OP_ne;
      goto do_scompare;

    do_scompare:
      if (GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0))) > DWARF2_ADDR_SIZE
          || GET_MODE_SIZE (GET_MODE (XEXP (rtl, 1))) > DWARF2_ADDR_SIZE)
        break;
      else
        {
          enum machine_mode op_mode = GET_MODE (XEXP (rtl, 0));

          if (op_mode == VOIDmode)
            op_mode = GET_MODE (XEXP (rtl, 1));
          if (op_mode != VOIDmode && GET_MODE_CLASS (op_mode) != MODE_INT)
            break;

          op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                    VAR_INIT_STATUS_INITIALIZED);
          op1 = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                    VAR_INIT_STATUS_INITIALIZED);

          if (op0 == 0 || op1 == 0)
            break;

          if (op_mode != VOIDmode
              && GET_MODE_SIZE (op_mode) < DWARF2_ADDR_SIZE)
            {
              int shift = DWARF2_ADDR_SIZE - GET_MODE_SIZE (op_mode);
              shift *= BITS_PER_UNIT;
              /* For eq/ne, if the operands are known to be zero-extended,
                 there is no need to do the fancy shifting up.  */
              if (op == DW_OP_eq || op == DW_OP_ne)
                {
                  dw_loc_descr_ref last0, last1;
                  for (last0 = op0;
                       last0->dw_loc_next != NULL;
                       last0 = last0->dw_loc_next)
                    ;
                  for (last1 = op1;
                       last1->dw_loc_next != NULL;
                       last1 = last1->dw_loc_next)
                    ;
                  /* deref_size zero extends, and for constants we can check
                     whether they are zero extended or not.  */
                  if (((last0->dw_loc_opc == DW_OP_deref_size
                        && last0->dw_loc_oprnd1.v.val_int
                           <= GET_MODE_SIZE (op_mode))
                       || (CONST_INT_P (XEXP (rtl, 0))
                            && (unsigned HOST_WIDE_INT) INTVAL (XEXP (rtl, 0))
                               == (INTVAL (XEXP (rtl, 0))
                                   & GET_MODE_MASK (op_mode))))
                      && ((last1->dw_loc_opc == DW_OP_deref_size
                           && last1->dw_loc_oprnd1.v.val_int
                              <= GET_MODE_SIZE (op_mode))
                          || (CONST_INT_P (XEXP (rtl, 1))
                              && (unsigned HOST_WIDE_INT)
                                 INTVAL (XEXP (rtl, 1))
                                 == (INTVAL (XEXP (rtl, 1))
                                     & GET_MODE_MASK (op_mode)))))
                    goto do_compare;
                }
              add_loc_descr (&op0, int_loc_descriptor (shift));
              add_loc_descr (&op0, new_loc_descr (DW_OP_shl, 0, 0));
              if (CONST_INT_P (XEXP (rtl, 1)))
                op1 = int_loc_descriptor (INTVAL (XEXP (rtl, 1)) << shift);
              else
                {
                  add_loc_descr (&op1, int_loc_descriptor (shift));
                  add_loc_descr (&op1, new_loc_descr (DW_OP_shl, 0, 0));
                }
            }
        }

    do_compare:
      mem_loc_result = op0;
      add_loc_descr (&mem_loc_result, op1);
      add_loc_descr (&mem_loc_result, new_loc_descr (op, 0, 0));
      if (STORE_FLAG_VALUE != 1)
        {
          add_loc_descr (&mem_loc_result,
                         int_loc_descriptor (STORE_FLAG_VALUE));
          add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_mul, 0, 0));
        }
      break;

    case GEU:
      op = DW_OP_ge;
      goto do_ucompare;

    case GTU:
      op = DW_OP_gt;
      goto do_ucompare;

    case LEU:
      op = DW_OP_le;
      goto do_ucompare;

    case LTU:
      op = DW_OP_lt;
      goto do_ucompare;

    do_ucompare:
      if (GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0))) > DWARF2_ADDR_SIZE
          || GET_MODE_SIZE (GET_MODE (XEXP (rtl, 1))) > DWARF2_ADDR_SIZE)
        break;
      else
        {
          enum machine_mode op_mode = GET_MODE (XEXP (rtl, 0));

          if (op_mode == VOIDmode)
            op_mode = GET_MODE (XEXP (rtl, 1));
          if (op_mode != VOIDmode && GET_MODE_CLASS (op_mode) != MODE_INT)
            break;

          op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                    VAR_INIT_STATUS_INITIALIZED);
          op1 = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                    VAR_INIT_STATUS_INITIALIZED);

          if (op0 == 0 || op1 == 0)
            break;

          if (op_mode != VOIDmode
              && GET_MODE_SIZE (op_mode) < DWARF2_ADDR_SIZE)
            {
              HOST_WIDE_INT mask = GET_MODE_MASK (op_mode);
              dw_loc_descr_ref last0, last1;
              for (last0 = op0;
                   last0->dw_loc_next != NULL;
                   last0 = last0->dw_loc_next)
                ;
              for (last1 = op1;
                   last1->dw_loc_next != NULL;
                   last1 = last1->dw_loc_next)
                ;
              if (CONST_INT_P (XEXP (rtl, 0)))
                op0 = int_loc_descriptor (INTVAL (XEXP (rtl, 0)) & mask);
              /* deref_size zero extends, so no need to mask it again.  */
              else if (last0->dw_loc_opc != DW_OP_deref_size
                       || last0->dw_loc_oprnd1.v.val_int
                          > GET_MODE_SIZE (op_mode))
                {
                  add_loc_descr (&op0, int_loc_descriptor (mask));
                  add_loc_descr (&op0, new_loc_descr (DW_OP_and, 0, 0));
                }
              if (CONST_INT_P (XEXP (rtl, 1)))
                op1 = int_loc_descriptor (INTVAL (XEXP (rtl, 1)) & mask);
              /* deref_size zero extends, so no need to mask it again.  */
              else if (last1->dw_loc_opc != DW_OP_deref_size
                       || last1->dw_loc_oprnd1.v.val_int
                          > GET_MODE_SIZE (op_mode))
                {
                  add_loc_descr (&op1, int_loc_descriptor (mask));
                  add_loc_descr (&op1, new_loc_descr (DW_OP_and, 0, 0));
                }
            }
          else
            {
              HOST_WIDE_INT bias = 1;
              bias <<= (DWARF2_ADDR_SIZE * BITS_PER_UNIT - 1);
              add_loc_descr (&op0, new_loc_descr (DW_OP_plus_uconst, bias, 0));
              if (CONST_INT_P (XEXP (rtl, 1)))
                op1 = int_loc_descriptor ((unsigned HOST_WIDE_INT) bias
                                          + INTVAL (XEXP (rtl, 1)));
              else
                add_loc_descr (&op1, new_loc_descr (DW_OP_plus_uconst,
                                                    bias, 0));
            }
        }
      goto do_compare;

    case SMIN:
    case SMAX:
    case UMIN:
    case UMAX:
      if (GET_MODE_CLASS (GET_MODE (XEXP (rtl, 0))) != MODE_INT
          || GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0))) > DWARF2_ADDR_SIZE
          || GET_MODE (XEXP (rtl, 0)) != GET_MODE (XEXP (rtl, 1)))
        break;

      op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                VAR_INIT_STATUS_INITIALIZED);
      op1 = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                VAR_INIT_STATUS_INITIALIZED);

      if (op0 == 0 || op1 == 0)
        break;

      add_loc_descr (&op0, new_loc_descr (DW_OP_dup, 0, 0));
      add_loc_descr (&op1, new_loc_descr (DW_OP_swap, 0, 0));
      add_loc_descr (&op1, new_loc_descr (DW_OP_over, 0, 0));
      if (GET_CODE (rtl) == UMIN || GET_CODE (rtl) == UMAX)
        {
          if (GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0))) < DWARF2_ADDR_SIZE)
            {
              HOST_WIDE_INT mask = GET_MODE_MASK (GET_MODE (XEXP (rtl, 0)));
              add_loc_descr (&op0, int_loc_descriptor (mask));
              add_loc_descr (&op0, new_loc_descr (DW_OP_and, 0, 0));
              add_loc_descr (&op1, int_loc_descriptor (mask));
              add_loc_descr (&op1, new_loc_descr (DW_OP_and, 0, 0));
            }
          else
            {
              HOST_WIDE_INT bias = 1;
              bias <<= (DWARF2_ADDR_SIZE * BITS_PER_UNIT - 1);
              add_loc_descr (&op0, new_loc_descr (DW_OP_plus_uconst, bias, 0));
              add_loc_descr (&op1, new_loc_descr (DW_OP_plus_uconst, bias, 0));
            }
        }
      else if (GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0))) < DWARF2_ADDR_SIZE)
        {
          int shift = DWARF2_ADDR_SIZE
                      - GET_MODE_SIZE (GET_MODE (XEXP (rtl, 0)));
          shift *= BITS_PER_UNIT;
          add_loc_descr (&op0, int_loc_descriptor (shift));
          add_loc_descr (&op0, new_loc_descr (DW_OP_shl, 0, 0));
          add_loc_descr (&op1, int_loc_descriptor (shift));
          add_loc_descr (&op1, new_loc_descr (DW_OP_shl, 0, 0));
        }

      if (GET_CODE (rtl) == SMIN || GET_CODE (rtl) == UMIN)
        op = DW_OP_lt;
      else
        op = DW_OP_gt;
      mem_loc_result = op0;
      add_loc_descr (&mem_loc_result, op1);
      add_loc_descr (&mem_loc_result, new_loc_descr (op, 0, 0));
      {
        dw_loc_descr_ref bra_node, drop_node;

        bra_node = new_loc_descr (DW_OP_bra, 0, 0);
        add_loc_descr (&mem_loc_result, bra_node);
        add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_swap, 0, 0));
        drop_node = new_loc_descr (DW_OP_drop, 0, 0);
        add_loc_descr (&mem_loc_result, drop_node);
        bra_node->dw_loc_oprnd1.val_class = dw_val_class_loc;
        bra_node->dw_loc_oprnd1.v.val_loc = drop_node;
      }
      break;

    case ZERO_EXTRACT:
    case SIGN_EXTRACT:
      if (CONST_INT_P (XEXP (rtl, 1))
          && CONST_INT_P (XEXP (rtl, 2))
          && ((unsigned) INTVAL (XEXP (rtl, 1))
              + (unsigned) INTVAL (XEXP (rtl, 2))
              <= GET_MODE_BITSIZE (GET_MODE (rtl)))
          && GET_MODE_BITSIZE (GET_MODE (rtl)) <= DWARF2_ADDR_SIZE
          && GET_MODE_BITSIZE (GET_MODE (XEXP (rtl, 0))) <= DWARF2_ADDR_SIZE)
        {
          int shift, size;
          op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                    VAR_INIT_STATUS_INITIALIZED);
          if (op0 == 0)
            break;
          if (GET_CODE (rtl) == SIGN_EXTRACT)
            op = DW_OP_shra;
          else
            op = DW_OP_shr;
          mem_loc_result = op0;
          size = INTVAL (XEXP (rtl, 1));
          shift = INTVAL (XEXP (rtl, 2));
          if (BITS_BIG_ENDIAN)
            shift = GET_MODE_BITSIZE (GET_MODE (XEXP (rtl, 0)))
                    - shift - size;
          if (shift + size != (int) DWARF2_ADDR_SIZE)
            {
              add_loc_descr (&mem_loc_result,
                             int_loc_descriptor (DWARF2_ADDR_SIZE
                                                 - shift - size));
              add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_shl, 0, 0));
            }
          if (size != (int) DWARF2_ADDR_SIZE)
            {
              add_loc_descr (&mem_loc_result,
                             int_loc_descriptor (DWARF2_ADDR_SIZE - size));
              add_loc_descr (&mem_loc_result, new_loc_descr (op, 0, 0));
            }
        }
      break;

    case IF_THEN_ELSE:
      {
        dw_loc_descr_ref op2, bra_node, drop_node;
        op0 = mem_loc_descriptor (XEXP (rtl, 0), mode,
                                  VAR_INIT_STATUS_INITIALIZED);
        op1 = mem_loc_descriptor (XEXP (rtl, 1), mode,
                                  VAR_INIT_STATUS_INITIALIZED);
        op2 = mem_loc_descriptor (XEXP (rtl, 2), mode,
                                  VAR_INIT_STATUS_INITIALIZED);
        if (op0 == NULL || op1 == NULL || op2 == NULL)
          break;

        mem_loc_result = op1;
        add_loc_descr (&mem_loc_result, op2);
        add_loc_descr (&mem_loc_result, op0);
        bra_node = new_loc_descr (DW_OP_bra, 0, 0);
        add_loc_descr (&mem_loc_result, bra_node);
        add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_swap, 0, 0));
        drop_node = new_loc_descr (DW_OP_drop, 0, 0);
        add_loc_descr (&mem_loc_result, drop_node);
        bra_node->dw_loc_oprnd1.val_class = dw_val_class_loc;
        bra_node->dw_loc_oprnd1.v.val_loc = drop_node;
      }
      break;

    case COMPARE:
    case ROTATE:
    case ROTATERT:
    case TRUNCATE:
      /* In theory, we could implement the above.  */
      /* DWARF cannot represent the unsigned compare operations
         natively.  */
    case SS_MULT:
    case US_MULT:
    case SS_DIV:
    case US_DIV:
    case SS_PLUS:
    case US_PLUS:
    case SS_MINUS:
    case US_MINUS:
    case SS_NEG:
    case US_NEG:
    case SS_ABS:
    case SS_ASHIFT:
    case US_ASHIFT:
    case SS_TRUNCATE:
    case US_TRUNCATE:
    case UDIV:
    case UNORDERED:
    case ORDERED:
    case UNEQ:
    case UNGE:
    case UNGT:
    case UNLE:
    case UNLT:
    case LTGT:
    case FLOAT_EXTEND:
    case FLOAT_TRUNCATE:
    case FLOAT:
    case UNSIGNED_FLOAT:
    case FIX:
    case UNSIGNED_FIX:
    case FRACT_CONVERT:
    case UNSIGNED_FRACT_CONVERT:
    case SAT_FRACT:
    case UNSIGNED_SAT_FRACT:
    case SQRT:
    case BSWAP:
    case FFS:
    case CLZ:
    case CTZ:
    case POPCOUNT:
    case PARITY:
    case ASM_OPERANDS:
    case VEC_MERGE:
    case VEC_SELECT:
    case VEC_CONCAT:
    case VEC_DUPLICATE:
    case UNSPEC:
    case HIGH:
      /* If delegitimize_address couldn't do anything with the UNSPEC, we
         can't express it in the debug info.  This can happen e.g. with some
         TLS UNSPECs.  */
      break;

    case CONST_STRING:
      resolve_one_addr (&rtl, NULL);
      goto symref;

    default:
#ifdef ENABLE_CHECKING
      print_rtl (stderr, rtl);
      gcc_unreachable ();
#else
      break;
#endif
    }

  if (mem_loc_result && initialized == VAR_INIT_STATUS_UNINITIALIZED)
    add_loc_descr (&mem_loc_result, new_loc_descr (DW_OP_GNU_uninit, 0, 0));

  return mem_loc_result;
}

/* Return a descriptor that describes the concatenation of two locations.
   This is typically a complex variable.  */

static dw_loc_descr_ref
concat_loc_descriptor (rtx x0, rtx x1, enum var_init_status initialized)
{
  dw_loc_descr_ref cc_loc_result = NULL;
  dw_loc_descr_ref x0_ref
    = loc_descriptor (x0, VOIDmode, VAR_INIT_STATUS_INITIALIZED);
  dw_loc_descr_ref x1_ref
    = loc_descriptor (x1, VOIDmode, VAR_INIT_STATUS_INITIALIZED);

  if (x0_ref == 0 || x1_ref == 0)
    return 0;

  cc_loc_result = x0_ref;
  add_loc_descr_op_piece (&cc_loc_result, GET_MODE_SIZE (GET_MODE (x0)));

  add_loc_descr (&cc_loc_result, x1_ref);
  add_loc_descr_op_piece (&cc_loc_result, GET_MODE_SIZE (GET_MODE (x1)));

  if (initialized == VAR_INIT_STATUS_UNINITIALIZED)
    add_loc_descr (&cc_loc_result, new_loc_descr (DW_OP_GNU_uninit, 0, 0));

  return cc_loc_result;
}

/* Return a descriptor that describes the concatenation of N
   locations.  */

static dw_loc_descr_ref
concatn_loc_descriptor (rtx concatn, enum var_init_status initialized)
{
  unsigned int i;
  dw_loc_descr_ref cc_loc_result = NULL;
  unsigned int n = XVECLEN (concatn, 0);

  for (i = 0; i < n; ++i)
    {
      dw_loc_descr_ref ref;
      rtx x = XVECEXP (concatn, 0, i);

      ref = loc_descriptor (x, VOIDmode, VAR_INIT_STATUS_INITIALIZED);
      if (ref == NULL)
        return NULL;

      add_loc_descr (&cc_loc_result, ref);
      add_loc_descr_op_piece (&cc_loc_result, GET_MODE_SIZE (GET_MODE (x)));
    }

  if (cc_loc_result && initialized == VAR_INIT_STATUS_UNINITIALIZED)
    add_loc_descr (&cc_loc_result, new_loc_descr (DW_OP_GNU_uninit, 0, 0));

  return cc_loc_result;
}

/* Helper function for loc_descriptor.  Return DW_OP_GNU_implicit_pointer
   for DEBUG_IMPLICIT_PTR RTL.  */

static dw_loc_descr_ref
implicit_ptr_descriptor (rtx rtl, HOST_WIDE_INT offset)
{
  dw_loc_descr_ref ret;
  dw_die_ref ref;

  if (dwarf_strict)
    return NULL;
  gcc_assert (TREE_CODE (DEBUG_IMPLICIT_PTR_DECL (rtl)) == VAR_DECL
              || TREE_CODE (DEBUG_IMPLICIT_PTR_DECL (rtl)) == PARM_DECL
              || TREE_CODE (DEBUG_IMPLICIT_PTR_DECL (rtl)) == RESULT_DECL);
  ref = lookup_decl_die (DEBUG_IMPLICIT_PTR_DECL (rtl));
  ret = new_loc_descr (DW_OP_GNU_implicit_pointer, 0, offset);
  ret->dw_loc_oprnd2.val_class = dw_val_class_const;
  if (ref)
    {
      ret->dw_loc_oprnd1.val_class = dw_val_class_die_ref;
      ret->dw_loc_oprnd1.v.val_die_ref.die = ref;
      ret->dw_loc_oprnd1.v.val_die_ref.external = 0;
    }
  else
    {
      ret->dw_loc_oprnd1.val_class = dw_val_class_decl_ref;
      ret->dw_loc_oprnd1.v.val_decl_ref = DEBUG_IMPLICIT_PTR_DECL (rtl);
    }
  return ret;
}

/* Output a proper Dwarf location descriptor for a variable or parameter
   which is either allocated in a register or in a memory location.  For a
   register, we just generate an OP_REG and the register number.  For a
   memory location we provide a Dwarf postfix expression describing how to
   generate the (dynamic) address of the object onto the address stack.

   MODE is mode of the decl if this loc_descriptor is going to be used in
   .debug_loc section where DW_OP_stack_value and DW_OP_implicit_value are
   allowed, VOIDmode otherwise.

   If we don't know how to describe it, return 0.  */

static dw_loc_descr_ref
loc_descriptor (rtx rtl, enum machine_mode mode,
                enum var_init_status initialized)
{
  dw_loc_descr_ref loc_result = NULL;

  switch (GET_CODE (rtl))
    {
    case SUBREG:
      /* The case of a subreg may arise when we have a local (register)
         variable or a formal (register) parameter which doesn't quite fill
         up an entire register.  For now, just assume that it is
         legitimate to make the Dwarf info refer to the whole register which
         contains the given subreg.  */
      loc_result = loc_descriptor (SUBREG_REG (rtl), mode, initialized);
      break;

    case REG:
      loc_result = reg_loc_descriptor (rtl, initialized);
      break;

    case MEM:
      loc_result = mem_loc_descriptor (XEXP (rtl, 0), GET_MODE (rtl),
                                       initialized);
      if (loc_result == NULL)
        loc_result = tls_mem_loc_descriptor (rtl);
      if (loc_result == NULL)
        {
          rtx new_rtl = avoid_constant_pool_reference (rtl);
          if (new_rtl != rtl)
            loc_result = loc_descriptor (new_rtl, mode, initialized);
        }
      break;

    case CONCAT:
      loc_result = concat_loc_descriptor (XEXP (rtl, 0), XEXP (rtl, 1),
                                          initialized);
      break;

    case CONCATN:
      loc_result = concatn_loc_descriptor (rtl, initialized);
      break;

    case VAR_LOCATION:
      /* Single part.  */
      if (GET_CODE (PAT_VAR_LOCATION_LOC (rtl)) != PARALLEL)
        {
          rtx loc = PAT_VAR_LOCATION_LOC (rtl);
          if (GET_CODE (loc) == EXPR_LIST)
            loc = XEXP (loc, 0);
          loc_result = loc_descriptor (loc, mode, initialized);
          break;
        }

      rtl = XEXP (rtl, 1);
      /* FALLTHRU */

    case PARALLEL:
      {
        rtvec par_elems = XVEC (rtl, 0);
        int num_elem = GET_NUM_ELEM (par_elems);
        enum machine_mode mode;
        int i;

        /* Create the first one, so we have something to add to.  */
        loc_result = loc_descriptor (XEXP (RTVEC_ELT (par_elems, 0), 0),
                                     VOIDmode, initialized);
        if (loc_result == NULL)
          return NULL;
        mode = GET_MODE (XEXP (RTVEC_ELT (par_elems, 0), 0));
        add_loc_descr_op_piece (&loc_result, GET_MODE_SIZE (mode));
        for (i = 1; i < num_elem; i++)
          {
            dw_loc_descr_ref temp;

            temp = loc_descriptor (XEXP (RTVEC_ELT (par_elems, i), 0),
                                   VOIDmode, initialized);
            if (temp == NULL)
              return NULL;
            add_loc_descr (&loc_result, temp);
            mode = GET_MODE (XEXP (RTVEC_ELT (par_elems, i), 0));
            add_loc_descr_op_piece (&loc_result, GET_MODE_SIZE (mode));
          }
      }
      break;

    case CONST_INT:
      if (mode != VOIDmode && mode != BLKmode)
        loc_result = address_of_int_loc_descriptor (GET_MODE_SIZE (mode),
                                                    INTVAL (rtl));
      break;

    case CONST_DOUBLE:
      if (mode == VOIDmode)
        mode = GET_MODE (rtl);

      if (mode != VOIDmode && (dwarf_version >= 4 || !dwarf_strict))
        {
          gcc_assert (mode == GET_MODE (rtl) || VOIDmode == GET_MODE (rtl));

          /* Note that a CONST_DOUBLE rtx could represent either an integer
             or a floating-point constant.  A CONST_DOUBLE is used whenever
             the constant requires more than one word in order to be
             adequately represented.  We output CONST_DOUBLEs as blocks.  */
          loc_result = new_loc_descr (DW_OP_implicit_value,
                                      GET_MODE_SIZE (mode), 0);
          if (SCALAR_FLOAT_MODE_P (mode))
            {
              unsigned int length = GET_MODE_SIZE (mode);
              unsigned char *array
                  = (unsigned char*) ggc_alloc_atomic (length);

              insert_float (rtl, array);
              loc_result->dw_loc_oprnd2.val_class = dw_val_class_vec;
              loc_result->dw_loc_oprnd2.v.val_vec.length = length / 4;
              loc_result->dw_loc_oprnd2.v.val_vec.elt_size = 4;
              loc_result->dw_loc_oprnd2.v.val_vec.array = array;
            }
          else
            {
              loc_result->dw_loc_oprnd2.val_class = dw_val_class_const_double;
              loc_result->dw_loc_oprnd2.v.val_double
                = rtx_to_double_int (rtl);
            }
        }
      break;

    case CONST_VECTOR:
      if (mode == VOIDmode)
        mode = GET_MODE (rtl);

      if (mode != VOIDmode && (dwarf_version >= 4 || !dwarf_strict))
        {
          unsigned int elt_size = GET_MODE_UNIT_SIZE (GET_MODE (rtl));
          unsigned int length = CONST_VECTOR_NUNITS (rtl);
          unsigned char *array = (unsigned char *)
            ggc_alloc_atomic (length * elt_size);
          unsigned int i;
          unsigned char *p;

          gcc_assert (mode == GET_MODE (rtl) || VOIDmode == GET_MODE (rtl));
          switch (GET_MODE_CLASS (mode))
            {
            case MODE_VECTOR_INT:
              for (i = 0, p = array; i < length; i++, p += elt_size)
                {
                  rtx elt = CONST_VECTOR_ELT (rtl, i);
                  double_int val = rtx_to_double_int (elt);

                  if (elt_size <= sizeof (HOST_WIDE_INT))
                    insert_int (double_int_to_shwi (val), elt_size, p);
                  else
                    {
                      gcc_assert (elt_size == 2 * sizeof (HOST_WIDE_INT));
                      insert_double (val, p);
                    }
                }
              break;

            case MODE_VECTOR_FLOAT:
              for (i = 0, p = array; i < length; i++, p += elt_size)
                {
                  rtx elt = CONST_VECTOR_ELT (rtl, i);
                  insert_float (elt, p);
                }
              break;

            default:
              gcc_unreachable ();
            }

          loc_result = new_loc_descr (DW_OP_implicit_value,
                                      length * elt_size, 0);
          loc_result->dw_loc_oprnd2.val_class = dw_val_class_vec;
          loc_result->dw_loc_oprnd2.v.val_vec.length = length;
          loc_result->dw_loc_oprnd2.v.val_vec.elt_size = elt_size;
          loc_result->dw_loc_oprnd2.v.val_vec.array = array;
        }
      break;

    case CONST:
      if (mode == VOIDmode
          || GET_CODE (XEXP (rtl, 0)) == CONST_INT
          || GET_CODE (XEXP (rtl, 0)) == CONST_DOUBLE
          || GET_CODE (XEXP (rtl, 0)) == CONST_VECTOR)
        {
          loc_result = loc_descriptor (XEXP (rtl, 0), mode, initialized);
          break;
        }
      /* FALLTHROUGH */
    case SYMBOL_REF:
      if (!const_ok_for_output (rtl))
        break;
    case LABEL_REF:
      if (mode != VOIDmode && GET_MODE_SIZE (mode) == DWARF2_ADDR_SIZE
          && (dwarf_version >= 4 || !dwarf_strict))
        {
          loc_result = new_loc_descr (DW_OP_addr, 0, 0);
          loc_result->dw_loc_oprnd1.val_class = dw_val_class_addr;
          loc_result->dw_loc_oprnd1.v.val_addr = rtl;
          add_loc_descr (&loc_result, new_loc_descr (DW_OP_stack_value, 0, 0));
          VEC_safe_push (rtx, gc, used_rtx_array, rtl);
        }
      break;

    case DEBUG_IMPLICIT_PTR:
      loc_result = implicit_ptr_descriptor (rtl, 0);
      break;

    case PLUS:
      if (GET_CODE (XEXP (rtl, 0)) == DEBUG_IMPLICIT_PTR
          && CONST_INT_P (XEXP (rtl, 1)))
        {
          loc_result
            = implicit_ptr_descriptor (XEXP (rtl, 0), INTVAL (XEXP (rtl, 1)));
          break;
        }
      /* FALLTHRU */
    default:
      if (GET_MODE_CLASS (mode) == MODE_INT && GET_MODE (rtl) == mode
          && GET_MODE_SIZE (GET_MODE (rtl)) <= DWARF2_ADDR_SIZE
          && (dwarf_version >= 4 || !dwarf_strict))
        {
          /* Value expression.  */
          loc_result = mem_loc_descriptor (rtl, VOIDmode, initialized);
          if (loc_result)
            add_loc_descr (&loc_result,
                           new_loc_descr (DW_OP_stack_value, 0, 0));
        }
      break;
    }

  return loc_result;
}

/* We need to figure out what section we should use as the base for the
   address ranges where a given location is valid.
   1. If this particular DECL has a section associated with it, use that.
   2. If this function has a section associated with it, use that.
   3. Otherwise, use the text section.
   XXX: If you split a variable across multiple sections, we won't notice.  */

static const char *
secname_for_decl (const_tree decl)
{
  const char *secname;

  if (VAR_OR_FUNCTION_DECL_P (decl) && DECL_SECTION_NAME (decl))
    {
      tree sectree = DECL_SECTION_NAME (decl);
      secname = TREE_STRING_POINTER (sectree);
    }
  else if (current_function_decl && DECL_SECTION_NAME (current_function_decl))
    {
      tree sectree = DECL_SECTION_NAME (current_function_decl);
      secname = TREE_STRING_POINTER (sectree);
    }
  else if (cfun && in_cold_section_p)
    secname = crtl->subsections.cold_section_label;
  else
    secname = text_section_label;

  return secname;
}

/* Return true when DECL_BY_REFERENCE is defined and set for DECL.  */

static bool
decl_by_reference_p (tree decl)
{
  return ((TREE_CODE (decl) == PARM_DECL || TREE_CODE (decl) == RESULT_DECL
           || TREE_CODE (decl) == VAR_DECL)
          && DECL_BY_REFERENCE (decl));
}

/* Helper function for dw_loc_list.  Compute proper Dwarf location descriptor
   for VARLOC.  */

static dw_loc_descr_ref
dw_loc_list_1 (tree loc, rtx varloc, int want_address,
               enum var_init_status initialized)
{
  int have_address = 0;
  dw_loc_descr_ref descr;
  enum machine_mode mode;

  if (want_address != 2)
    {
      gcc_assert (GET_CODE (varloc) == VAR_LOCATION);
      /* Single part.  */
      if (GET_CODE (PAT_VAR_LOCATION_LOC (varloc)) != PARALLEL)
        {
          varloc = PAT_VAR_LOCATION_LOC (varloc);
          if (GET_CODE (varloc) == EXPR_LIST)
            varloc = XEXP (varloc, 0);
          mode = GET_MODE (varloc);
          if (MEM_P (varloc))
            {
              rtx addr = XEXP (varloc, 0);
              descr = mem_loc_descriptor (addr, mode, initialized);
              if (descr)
                have_address = 1;
              else
                {
                  rtx x = avoid_constant_pool_reference (varloc);
                  if (x != varloc)
                    descr = mem_loc_descriptor (x, mode, initialized);
                }
            }
          else
            descr = mem_loc_descriptor (varloc, mode, initialized);
        }
      else
        return 0;
    }
  else
    {
      if (GET_CODE (varloc) == VAR_LOCATION)
        mode = DECL_MODE (PAT_VAR_LOCATION_DECL (varloc));
      else
        mode = DECL_MODE (loc);
      descr = loc_descriptor (varloc, mode, initialized);
      have_address = 1;
    }

  if (!descr)
    return 0;

  if (want_address == 2 && !have_address
      && (dwarf_version >= 4 || !dwarf_strict))
    {
      if (int_size_in_bytes (TREE_TYPE (loc)) > DWARF2_ADDR_SIZE)
        {
          expansion_failed (loc, NULL_RTX,
                            "DWARF address size mismatch");
          return 0;
        }
      add_loc_descr (&descr, new_loc_descr (DW_OP_stack_value, 0, 0));
      have_address = 1;
    }
  /* Show if we can't fill the request for an address.  */
  if (want_address && !have_address)
    {
      expansion_failed (loc, NULL_RTX,
                        "Want address and only have value");
      return 0;
    }

  /* If we've got an address and don't want one, dereference.  */
  if (!want_address && have_address)
    {
      HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (loc));
      enum dwarf_location_atom op;

      if (size > DWARF2_ADDR_SIZE || size == -1)
        {
          expansion_failed (loc, NULL_RTX,
                            "DWARF address size mismatch");
          return 0;
        }
      else if (size == DWARF2_ADDR_SIZE)
        op = DW_OP_deref;
      else
        op = DW_OP_deref_size;

      add_loc_descr (&descr, new_loc_descr (op, size, 0));
    }

  return descr;
}

/* Create a DW_OP_piece or DW_OP_bit_piece for bitsize, or return NULL
   if it is not possible.  */

static dw_loc_descr_ref
new_loc_descr_op_bit_piece (HOST_WIDE_INT bitsize, HOST_WIDE_INT offset)
{
  if ((bitsize % BITS_PER_UNIT) == 0 && offset == 0)
    return new_loc_descr (DW_OP_piece, bitsize / BITS_PER_UNIT, 0);
  else if (dwarf_version >= 3 || !dwarf_strict)
    return new_loc_descr (DW_OP_bit_piece, bitsize, offset);
  else
    return NULL;
}

/* Helper function for dw_loc_list.  Compute proper Dwarf location descriptor
   for VAR_LOC_NOTE for variable DECL that has been optimized by SRA.  */

static dw_loc_descr_ref
dw_sra_loc_expr (tree decl, rtx loc)
{
  rtx p;
  unsigned int padsize = 0;
  dw_loc_descr_ref descr, *descr_tail;
  unsigned HOST_WIDE_INT decl_size;
  rtx varloc;
  enum var_init_status initialized;

  if (DECL_SIZE (decl) == NULL
      || !host_integerp (DECL_SIZE (decl), 1))
    return NULL;

  decl_size = tree_low_cst (DECL_SIZE (decl), 1);
  descr = NULL;
  descr_tail = &descr;

  for (p = loc; p; p = XEXP (p, 1))
    {
      unsigned int bitsize = decl_piece_bitsize (p);
      rtx loc_note = *decl_piece_varloc_ptr (p);
      dw_loc_descr_ref cur_descr;
      dw_loc_descr_ref *tail, last = NULL;
      unsigned int opsize = 0;

      if (loc_note == NULL_RTX
          || NOTE_VAR_LOCATION_LOC (loc_note) == NULL_RTX)
        {
          padsize += bitsize;
          continue;
        }
      initialized = NOTE_VAR_LOCATION_STATUS (loc_note);
      varloc = NOTE_VAR_LOCATION (loc_note);
      cur_descr = dw_loc_list_1 (decl, varloc, 2, initialized);
      if (cur_descr == NULL)
        {
          padsize += bitsize;
          continue;
        }

      /* Check that cur_descr either doesn't use
         DW_OP_*piece operations, or their sum is equal
         to bitsize.  Otherwise we can't embed it.  */
      for (tail = &cur_descr; *tail != NULL;
           tail = &(*tail)->dw_loc_next)
        if ((*tail)->dw_loc_opc == DW_OP_piece)
          {
            opsize += (*tail)->dw_loc_oprnd1.v.val_unsigned
                      * BITS_PER_UNIT;
            last = *tail;
          }
        else if ((*tail)->dw_loc_opc == DW_OP_bit_piece)
          {
            opsize += (*tail)->dw_loc_oprnd1.v.val_unsigned;
            last = *tail;
          }

      if (last != NULL && opsize != bitsize)
        {
          padsize += bitsize;
          continue;
        }

      /* If there is a hole, add DW_OP_*piece after empty DWARF
         expression, which means that those bits are optimized out.  */
      if (padsize)
        {
          if (padsize > decl_size)
            return NULL;
          decl_size -= padsize;
          *descr_tail = new_loc_descr_op_bit_piece (padsize, 0);
          if (*descr_tail == NULL)
            return NULL;
          descr_tail = &(*descr_tail)->dw_loc_next;
          padsize = 0;
        }
      *descr_tail = cur_descr;
      descr_tail = tail;
      if (bitsize > decl_size)
        return NULL;
      decl_size -= bitsize;
      if (last == NULL)
        {
          HOST_WIDE_INT offset = 0;
          if (GET_CODE (varloc) == VAR_LOCATION
              && GET_CODE (PAT_VAR_LOCATION_LOC (varloc)) != PARALLEL)
            {
              varloc = PAT_VAR_LOCATION_LOC (varloc);
              if (GET_CODE (varloc) == EXPR_LIST)
                varloc = XEXP (varloc, 0);
            }
          do 
            {
              if (GET_CODE (varloc) == CONST
                  || GET_CODE (varloc) == SIGN_EXTEND
                  || GET_CODE (varloc) == ZERO_EXTEND)
                varloc = XEXP (varloc, 0);
              else if (GET_CODE (varloc) == SUBREG)
                varloc = SUBREG_REG (varloc);
              else
                break;
            }
          while (1);
          /* DW_OP_bit_size offset should be zero for register
             or implicit location descriptions and empty location
             descriptions, but for memory addresses needs big endian
             adjustment.  */
          if (MEM_P (varloc))
            {
              unsigned HOST_WIDE_INT memsize
                = INTVAL (MEM_SIZE (varloc)) * BITS_PER_UNIT;
              if (memsize != bitsize)
                {
                  if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN
                      && (memsize > BITS_PER_WORD || bitsize > BITS_PER_WORD))
                    return NULL;
                  if (memsize < bitsize)
                    return NULL;
                  if (BITS_BIG_ENDIAN)
                    offset = memsize - bitsize;
                }
            }

          *descr_tail = new_loc_descr_op_bit_piece (bitsize, offset);
          if (*descr_tail == NULL)
            return NULL;
          descr_tail = &(*descr_tail)->dw_loc_next;
        }
    }

  /* If there were any non-empty expressions, add padding till the end of
     the decl.  */
  if (descr != NULL && decl_size != 0)
    {
      *descr_tail = new_loc_descr_op_bit_piece (decl_size, 0);
      if (*descr_tail == NULL)
        return NULL;
    }
  return descr;
}

/* Return the dwarf representation of the location list LOC_LIST of
   DECL.  WANT_ADDRESS has the same meaning as in loc_list_from_tree
   function.  */

static dw_loc_list_ref
dw_loc_list (var_loc_list *loc_list, tree decl, int want_address)
{
  const char *endname, *secname;
  rtx varloc;
  enum var_init_status initialized;
  struct var_loc_node *node;
  dw_loc_descr_ref descr;
  char label_id[MAX_ARTIFICIAL_LABEL_BYTES];
  dw_loc_list_ref list = NULL;
  dw_loc_list_ref *listp = &list;

  /* Now that we know what section we are using for a base,
     actually construct the list of locations.
     The first location information is what is passed to the
     function that creates the location list, and the remaining
     locations just get added on to that list.
     Note that we only know the start address for a location
     (IE location changes), so to build the range, we use
     the range [current location start, next location start].
     This means we have to special case the last node, and generate
     a range of [last location start, end of function label].  */

  secname = secname_for_decl (decl);

  for (node = loc_list->first; node; node = node->next)
    if (GET_CODE (node->loc) == EXPR_LIST
        || NOTE_VAR_LOCATION_LOC (node->loc) != NULL_RTX)
      {
        if (GET_CODE (node->loc) == EXPR_LIST)
          {
            /* This requires DW_OP_{,bit_}piece, which is not usable
               inside DWARF expressions.  */
            if (want_address != 2)
              continue;
            descr = dw_sra_loc_expr (decl, node->loc);
            if (descr == NULL)
              continue;
          }
        else
          {
            initialized = NOTE_VAR_LOCATION_STATUS (node->loc);
            varloc = NOTE_VAR_LOCATION (node->loc);
            descr = dw_loc_list_1 (decl, varloc, want_address, initialized);
          }
        if (descr)
          {
            /* The variable has a location between NODE->LABEL and
               NODE->NEXT->LABEL.  */
            if (node->next)
              endname = node->next->label;
            /* If the variable has a location at the last label
               it keeps its location until the end of function.  */
            else if (!current_function_decl)
              endname = text_end_label;
            else
              {
                ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_END_LABEL,
                                             current_function_funcdef_no);
                endname = ggc_strdup (label_id);
              }

            *listp = new_loc_list (descr, node->label, endname, secname);
            listp = &(*listp)->dw_loc_next;
          }
      }

  /* Try to avoid the overhead of a location list emitting a location
     expression instead, but only if we didn't have more than one
     location entry in the first place.  If some entries were not
     representable, we don't want to pretend a single entry that was
     applies to the entire scope in which the variable is
     available.  */
  if (list && loc_list->first->next)
    gen_llsym (list);

  return list;
}

/* Return if the loc_list has only single element and thus can be represented
   as location description.   */

static bool
single_element_loc_list_p (dw_loc_list_ref list)
{
  gcc_assert (!list->dw_loc_next || list->ll_symbol);
  return !list->ll_symbol;
}

/* To each location in list LIST add loc descr REF.  */

static void
add_loc_descr_to_each (dw_loc_list_ref list, dw_loc_descr_ref ref)
{
  dw_loc_descr_ref copy;
  add_loc_descr (&list->expr, ref);
  list = list->dw_loc_next;
  while (list)
    {
      copy = ggc_alloc_dw_loc_descr_node ();
      memcpy (copy, ref, sizeof (dw_loc_descr_node));
      add_loc_descr (&list->expr, copy);
      while (copy->dw_loc_next)
        {
          dw_loc_descr_ref new_copy = ggc_alloc_dw_loc_descr_node ();
          memcpy (new_copy, copy->dw_loc_next, sizeof (dw_loc_descr_node));
          copy->dw_loc_next = new_copy;
          copy = new_copy;
        }
      list = list->dw_loc_next;
    }
}

/* Given two lists RET and LIST
   produce location list that is result of adding expression in LIST
   to expression in RET on each possition in program.
   Might be destructive on both RET and LIST.

   TODO: We handle only simple cases of RET or LIST having at most one
   element. General case would inolve sorting the lists in program order
   and merging them that will need some additional work.
   Adding that will improve quality of debug info especially for SRA-ed
   structures.  */

static void
add_loc_list (dw_loc_list_ref *ret, dw_loc_list_ref list)
{
  if (!list)
    return;
  if (!*ret)
    {
      *ret = list;
      return;
    }
  if (!list->dw_loc_next)
    {
      add_loc_descr_to_each (*ret, list->expr);
      return;
    }
  if (!(*ret)->dw_loc_next)
    {
      add_loc_descr_to_each (list, (*ret)->expr);
      *ret = list;
      return;
    }
  expansion_failed (NULL_TREE, NULL_RTX,
                    "Don't know how to merge two non-trivial"
                    " location lists.\n");
  *ret = NULL;
  return;
}

/* LOC is constant expression.  Try a luck, look it up in constant
   pool and return its loc_descr of its address.  */

static dw_loc_descr_ref
cst_pool_loc_descr (tree loc)
{
  /* Get an RTL for this, if something has been emitted.  */
  rtx rtl = lookup_constant_def (loc);
  enum machine_mode mode;

  if (!rtl || !MEM_P (rtl))
    {
      gcc_assert (!rtl);
      return 0;
    }
  gcc_assert (GET_CODE (XEXP (rtl, 0)) == SYMBOL_REF);

  /* TODO: We might get more coverage if we was actually delaying expansion
     of all expressions till end of compilation when constant pools are fully
     populated.  */
  if (!TREE_ASM_WRITTEN (SYMBOL_REF_DECL (XEXP (rtl, 0))))
    {
      expansion_failed (loc, NULL_RTX,
                        "CST value in contant pool but not marked.");
      return 0;
    }
  mode = GET_MODE (rtl);
  rtl = XEXP (rtl, 0);
  return mem_loc_descriptor (rtl, mode, VAR_INIT_STATUS_INITIALIZED);
}

/* Return dw_loc_list representing address of addr_expr LOC
   by looking for innder INDIRECT_REF expression and turing it
   into simple arithmetics.  */

static dw_loc_list_ref
loc_list_for_address_of_addr_expr_of_indirect_ref (tree loc, bool toplev)
{
  tree obj, offset;
  HOST_WIDE_INT bitsize, bitpos, bytepos;
  enum machine_mode mode;
  int volatilep;
  int unsignedp = TYPE_UNSIGNED (TREE_TYPE (loc));
  dw_loc_list_ref list_ret = NULL, list_ret1 = NULL;

  obj = get_inner_reference (TREE_OPERAND (loc, 0),
                             &bitsize, &bitpos, &offset, &mode,
                             &unsignedp, &volatilep, false);
  STRIP_NOPS (obj);
  if (bitpos % BITS_PER_UNIT)
    {
      expansion_failed (loc, NULL_RTX, "bitfield access");
      return 0;
    }
  if (!INDIRECT_REF_P (obj))
    {
      expansion_failed (obj,
                        NULL_RTX, "no indirect ref in inner refrence");
      return 0;
    }
  if (!offset && !bitpos)
    list_ret = loc_list_from_tree (TREE_OPERAND (obj, 0), toplev ? 2 : 1);
  else if (toplev
           && int_size_in_bytes (TREE_TYPE (loc)) <= DWARF2_ADDR_SIZE
           && (dwarf_version >= 4 || !dwarf_strict))
    {
      list_ret = loc_list_from_tree (TREE_OPERAND (obj, 0), 0);
      if (!list_ret)
        return 0;
      if (offset)
        {
          /* Variable offset.  */
          list_ret1 = loc_list_from_tree (offset, 0);
          if (list_ret1 == 0)
            return 0;
          add_loc_list (&list_ret, list_ret1);
          if (!list_ret)
            return 0;
          add_loc_descr_to_each (list_ret,
                                 new_loc_descr (DW_OP_plus, 0, 0));
        }
      bytepos = bitpos / BITS_PER_UNIT;
      if (bytepos > 0)
        add_loc_descr_to_each (list_ret,
                               new_loc_descr (DW_OP_plus_uconst,
                                              bytepos, 0));
      else if (bytepos < 0)
        loc_list_plus_const (list_ret, bytepos);
      add_loc_descr_to_each (list_ret,
                             new_loc_descr (DW_OP_stack_value, 0, 0));
    }
  return list_ret;
}


/* Generate Dwarf location list representing LOC.
   If WANT_ADDRESS is false, expression computing LOC will be computed
   If WANT_ADDRESS is 1, expression computing address of LOC will be returned
   if WANT_ADDRESS is 2, expression computing address useable in location
     will be returned (i.e. DW_OP_reg can be used
     to refer to register values).  */

static dw_loc_list_ref
loc_list_from_tree (tree loc, int want_address)
{
  dw_loc_descr_ref ret = NULL, ret1 = NULL;
  dw_loc_list_ref list_ret = NULL, list_ret1 = NULL;
  int have_address = 0;
  enum dwarf_location_atom op;

  /* ??? Most of the time we do not take proper care for sign/zero
     extending the values properly.  Hopefully this won't be a real
     problem...  */

  switch (TREE_CODE (loc))
    {
    case ERROR_MARK:
      expansion_failed (loc, NULL_RTX, "ERROR_MARK");
      return 0;

    case PLACEHOLDER_EXPR:
      /* This case involves extracting fields from an object to determine the
         position of other fields.  We don't try to encode this here.  The
         only user of this is Ada, which encodes the needed information using
         the names of types.  */
      expansion_failed (loc, NULL_RTX, "PLACEHOLDER_EXPR");
      return 0;

    case CALL_EXPR:
      expansion_failed (loc, NULL_RTX, "CALL_EXPR");
      /* There are no opcodes for these operations.  */
      return 0;

    case PREINCREMENT_EXPR:
    case PREDECREMENT_EXPR:
    case POSTINCREMENT_EXPR:
    case POSTDECREMENT_EXPR:
      expansion_failed (loc, NULL_RTX, "PRE/POST INDCREMENT/DECREMENT");
      /* There are no opcodes for these operations.  */
      return 0;

    case ADDR_EXPR:
      /* If we already want an address, see if there is INDIRECT_REF inside
         e.g. for &this->field.  */
      if (want_address)
        {
          list_ret = loc_list_for_address_of_addr_expr_of_indirect_ref
                       (loc, want_address == 2);
          if (list_ret)
            have_address = 1;
          else if (decl_address_ip_invariant_p (TREE_OPERAND (loc, 0))
                   && (ret = cst_pool_loc_descr (loc)))
            have_address = 1;
        }
        /* Otherwise, process the argument and look for the address.  */
      if (!list_ret && !ret)
        list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 1);
      else
        {
          if (want_address)
            expansion_failed (loc, NULL_RTX, "need address of ADDR_EXPR");
          return NULL;
        }
      break;

    case VAR_DECL:
      if (DECL_THREAD_LOCAL_P (loc))
        {
          rtx rtl;
          enum dwarf_location_atom first_op;
          enum dwarf_location_atom second_op;
          bool dtprel = false;

          if (targetm.have_tls)
            {
              /* If this is not defined, we have no way to emit the
                 data.  */
              if (!targetm.asm_out.output_dwarf_dtprel)
                return 0;

               /* The way DW_OP_GNU_push_tls_address is specified, we
                  can only look up addresses of objects in the current
                  module.  We used DW_OP_addr as first op, but that's
                  wrong, because DW_OP_addr is relocated by the debug
                  info consumer, while DW_OP_GNU_push_tls_address
                  operand shouldn't be.  */
              if (DECL_EXTERNAL (loc) && !targetm.binds_local_p (loc))
                return 0;
              first_op = DWARF2_ADDR_SIZE == 4 ? DW_OP_const4u : DW_OP_const8u;
              dtprel = true;
              second_op = DW_OP_GNU_push_tls_address;
            }
          else
            {
              if (!targetm.emutls.debug_form_tls_address
                  || !(dwarf_version >= 3 || !dwarf_strict))
                return 0;
              /* We stuffed the control variable into the DECL_VALUE_EXPR
                 to signal (via DECL_HAS_VALUE_EXPR_P) that the decl should
                 no longer appear in gimple code.  We used the control
                 variable in specific so that we could pick it up here.  */
              loc = DECL_VALUE_EXPR (loc);
              first_op = DW_OP_addr;
              second_op = DW_OP_form_tls_address;
            }

          rtl = rtl_for_decl_location (loc);
          if (rtl == NULL_RTX)
            return 0;

          if (!MEM_P (rtl))
            return 0;
          rtl = XEXP (rtl, 0);
          if (! CONSTANT_P (rtl))
            return 0;

          ret = new_loc_descr (first_op, 0, 0);
          ret->dw_loc_oprnd1.val_class = dw_val_class_addr;
          ret->dw_loc_oprnd1.v.val_addr = rtl;
          ret->dtprel = dtprel;

          ret1 = new_loc_descr (second_op, 0, 0);
          add_loc_descr (&ret, ret1);

          have_address = 1;
          break;
        }
      /* FALLTHRU */

    case PARM_DECL:
    case RESULT_DECL:
      if (DECL_HAS_VALUE_EXPR_P (loc))
        return loc_list_from_tree (DECL_VALUE_EXPR (loc),
                                   want_address);
      /* FALLTHRU */

    case FUNCTION_DECL:
      {
        rtx rtl;
        var_loc_list *loc_list = lookup_decl_loc (loc);

        if (loc_list && loc_list->first)
          {
            list_ret = dw_loc_list (loc_list, loc, want_address);
            have_address = want_address != 0;
            break;
          }
        rtl = rtl_for_decl_location (loc);
        if (rtl == NULL_RTX)
          {
            expansion_failed (loc, NULL_RTX, "DECL has no RTL");
            return 0;
          }
        else if (CONST_INT_P (rtl))
          {
            HOST_WIDE_INT val = INTVAL (rtl);
            if (TYPE_UNSIGNED (TREE_TYPE (loc)))
              val &= GET_MODE_MASK (DECL_MODE (loc));
            ret = int_loc_descriptor (val);
          }
        else if (GET_CODE (rtl) == CONST_STRING)
          {
            expansion_failed (loc, NULL_RTX, "CONST_STRING");
            return 0;
          }
        else if (CONSTANT_P (rtl) && const_ok_for_output (rtl))
          {
            ret = new_loc_descr (DW_OP_addr, 0, 0);
            ret->dw_loc_oprnd1.val_class = dw_val_class_addr;
            ret->dw_loc_oprnd1.v.val_addr = rtl;
          }
        else
          {
            enum machine_mode mode;

            /* Certain constructs can only be represented at top-level.  */
            if (want_address == 2)
              {
                ret = loc_descriptor (rtl, VOIDmode,
                                      VAR_INIT_STATUS_INITIALIZED);
                have_address = 1;
              }
            else
              {
                mode = GET_MODE (rtl);
                if (MEM_P (rtl))
                  {
                    rtl = XEXP (rtl, 0);
                    have_address = 1;
                  }
                ret = mem_loc_descriptor (rtl, mode, VAR_INIT_STATUS_INITIALIZED);
              }
            if (!ret)
              expansion_failed (loc, rtl,
                                "failed to produce loc descriptor for rtl");
          }
      }
      break;

    case MEM_REF:
      /* ??? FIXME.  */
      if (!integer_zerop (TREE_OPERAND (loc, 1)))
        return 0;
      /* Fallthru.  */
    case INDIRECT_REF:
      list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
      have_address = 1;
      break;

    case COMPOUND_EXPR:
      return loc_list_from_tree (TREE_OPERAND (loc, 1), want_address);

    CASE_CONVERT:
    case VIEW_CONVERT_EXPR:
    case SAVE_EXPR:
    case MODIFY_EXPR:
      return loc_list_from_tree (TREE_OPERAND (loc, 0), want_address);

    case COMPONENT_REF:
    case BIT_FIELD_REF:
    case ARRAY_REF:
    case ARRAY_RANGE_REF:
    case REALPART_EXPR:
    case IMAGPART_EXPR:
      {
        tree obj, offset;
        HOST_WIDE_INT bitsize, bitpos, bytepos;
        enum machine_mode mode;
        int volatilep;
        int unsignedp = TYPE_UNSIGNED (TREE_TYPE (loc));

        obj = get_inner_reference (loc, &bitsize, &bitpos, &offset, &mode,
                                   &unsignedp, &volatilep, false);

        gcc_assert (obj != loc);

        list_ret = loc_list_from_tree (obj,
                                       want_address == 2
                                       && !bitpos && !offset ? 2 : 1);
        /* TODO: We can extract value of the small expression via shifting even
           for nonzero bitpos.  */
        if (list_ret == 0)
          return 0;
        if (bitpos % BITS_PER_UNIT != 0 || bitsize % BITS_PER_UNIT != 0)
          {
            expansion_failed (loc, NULL_RTX,
                              "bitfield access");
            return 0;
          }

        if (offset != NULL_TREE)
          {
            /* Variable offset.  */
            list_ret1 = loc_list_from_tree (offset, 0);
            if (list_ret1 == 0)
              return 0;
            add_loc_list (&list_ret, list_ret1);
            if (!list_ret)
              return 0;
            add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_plus, 0, 0));
          }

        bytepos = bitpos / BITS_PER_UNIT;
        if (bytepos > 0)
          add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_plus_uconst, bytepos, 0));
        else if (bytepos < 0)
          loc_list_plus_const (list_ret, bytepos);

        have_address = 1;
        break;
      }

    case INTEGER_CST:
      if ((want_address || !host_integerp (loc, 0))
          && (ret = cst_pool_loc_descr (loc)))
        have_address = 1;
      else if (want_address == 2
               && host_integerp (loc, 0)
               && (ret = address_of_int_loc_descriptor
                           (int_size_in_bytes (TREE_TYPE (loc)),
                            tree_low_cst (loc, 0))))
        have_address = 1;
      else if (host_integerp (loc, 0))
        ret = int_loc_descriptor (tree_low_cst (loc, 0));
      else
        {
          expansion_failed (loc, NULL_RTX,
                            "Integer operand is not host integer");
          return 0;
        }
      break;

    case CONSTRUCTOR:
    case REAL_CST:
    case STRING_CST:
    case COMPLEX_CST:
      if ((ret = cst_pool_loc_descr (loc)))
        have_address = 1;
      else
      /* We can construct small constants here using int_loc_descriptor.  */
        expansion_failed (loc, NULL_RTX,
                          "constructor or constant not in constant pool");
      break;

    case TRUTH_AND_EXPR:
    case TRUTH_ANDIF_EXPR:
    case BIT_AND_EXPR:
      op = DW_OP_and;
      goto do_binop;

    case TRUTH_XOR_EXPR:
    case BIT_XOR_EXPR:
      op = DW_OP_xor;
      goto do_binop;

    case TRUTH_OR_EXPR:
    case TRUTH_ORIF_EXPR:
    case BIT_IOR_EXPR:
      op = DW_OP_or;
      goto do_binop;

    case FLOOR_DIV_EXPR:
    case CEIL_DIV_EXPR:
    case ROUND_DIV_EXPR:
    case TRUNC_DIV_EXPR:
      if (TYPE_UNSIGNED (TREE_TYPE (loc)))
        return 0;
      op = DW_OP_div;
      goto do_binop;

    case MINUS_EXPR:
      op = DW_OP_minus;
      goto do_binop;

    case FLOOR_MOD_EXPR:
    case CEIL_MOD_EXPR:
    case ROUND_MOD_EXPR:
    case TRUNC_MOD_EXPR:
      if (TYPE_UNSIGNED (TREE_TYPE (loc)))
        {
          op = DW_OP_mod;
          goto do_binop;
        }
      list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
      list_ret1 = loc_list_from_tree (TREE_OPERAND (loc, 1), 0);
      if (list_ret == 0 || list_ret1 == 0)
        return 0;

      add_loc_list (&list_ret, list_ret1);
      if (list_ret == 0)
        return 0;
      add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_over, 0, 0));
      add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_over, 0, 0));
      add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_div, 0, 0));
      add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_mul, 0, 0));
      add_loc_descr_to_each (list_ret, new_loc_descr (DW_OP_minus, 0, 0));
      break;

    case MULT_EXPR:
      op = DW_OP_mul;
      goto do_binop;

    case LSHIFT_EXPR:
      op = DW_OP_shl;
      goto do_binop;

    case RSHIFT_EXPR:
      op = (TYPE_UNSIGNED (TREE_TYPE (loc)) ? DW_OP_shr : DW_OP_shra);
      goto do_binop;

    case POINTER_PLUS_EXPR:
    case PLUS_EXPR:
      if (host_integerp (TREE_OPERAND (loc, 1), 0))
        {
          list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
          if (list_ret == 0)
            return 0;

          loc_list_plus_const (list_ret, tree_low_cst (TREE_OPERAND (loc, 1), 0));
          break;
        }

      op = DW_OP_plus;
      goto do_binop;

    case LE_EXPR:
      if (TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (loc, 0))))
        return 0;

      op = DW_OP_le;
      goto do_binop;

    case GE_EXPR:
      if (TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (loc, 0))))
        return 0;

      op = DW_OP_ge;
      goto do_binop;

    case LT_EXPR:
      if (TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (loc, 0))))
        return 0;

      op = DW_OP_lt;
      goto do_binop;

    case GT_EXPR:
      if (TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (loc, 0))))
        return 0;

      op = DW_OP_gt;
      goto do_binop;

    case EQ_EXPR:
      op = DW_OP_eq;
      goto do_binop;

    case NE_EXPR:
      op = DW_OP_ne;
      goto do_binop;

    do_binop:
      list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
      list_ret1 = loc_list_from_tree (TREE_OPERAND (loc, 1), 0);
      if (list_ret == 0 || list_ret1 == 0)
        return 0;

      add_loc_list (&list_ret, list_ret1);
      if (list_ret == 0)
        return 0;
      add_loc_descr_to_each (list_ret, new_loc_descr (op, 0, 0));
      break;

    case TRUTH_NOT_EXPR:
    case BIT_NOT_EXPR:
      op = DW_OP_not;
      goto do_unop;

    case ABS_EXPR:
      op = DW_OP_abs;
      goto do_unop;

    case NEGATE_EXPR:
      op = DW_OP_neg;
      goto do_unop;

    do_unop:
      list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
      if (list_ret == 0)
        return 0;

      add_loc_descr_to_each (list_ret, new_loc_descr (op, 0, 0));
      break;

    case MIN_EXPR:
    case MAX_EXPR:
      {
        const enum tree_code code =
          TREE_CODE (loc) == MIN_EXPR ? GT_EXPR : LT_EXPR;

        loc = build3 (COND_EXPR, TREE_TYPE (loc),
                      build2 (code, integer_type_node,
                              TREE_OPERAND (loc, 0), TREE_OPERAND (loc, 1)),
                      TREE_OPERAND (loc, 1), TREE_OPERAND (loc, 0));
      }

      /* ... fall through ...  */

    case COND_EXPR:
      {
        dw_loc_descr_ref lhs
          = loc_descriptor_from_tree (TREE_OPERAND (loc, 1), 0);
        dw_loc_list_ref rhs
          = loc_list_from_tree (TREE_OPERAND (loc, 2), 0);
        dw_loc_descr_ref bra_node, jump_node, tmp;

        list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
        if (list_ret == 0 || lhs == 0 || rhs == 0)
          return 0;

        bra_node = new_loc_descr (DW_OP_bra, 0, 0);
        add_loc_descr_to_each (list_ret, bra_node);

        add_loc_list (&list_ret, rhs);
        jump_node = new_loc_descr (DW_OP_skip, 0, 0);
        add_loc_descr_to_each (list_ret, jump_node);

        add_loc_descr_to_each (list_ret, lhs);
        bra_node->dw_loc_oprnd1.val_class = dw_val_class_loc;
        bra_node->dw_loc_oprnd1.v.val_loc = lhs;

        /* ??? Need a node to point the skip at.  Use a nop.  */
        tmp = new_loc_descr (DW_OP_nop, 0, 0);
        add_loc_descr_to_each (list_ret, tmp);
        jump_node->dw_loc_oprnd1.val_class = dw_val_class_loc;
        jump_node->dw_loc_oprnd1.v.val_loc = tmp;
      }
      break;

    case FIX_TRUNC_EXPR:
      return 0;

    default:
      /* Leave front-end specific codes as simply unknown.  This comes
         up, for instance, with the C STMT_EXPR.  */
      if ((unsigned int) TREE_CODE (loc)
          >= (unsigned int) LAST_AND_UNUSED_TREE_CODE)
        {
          expansion_failed (loc, NULL_RTX,
                            "language specific tree node");
          return 0;
        }

#ifdef ENABLE_CHECKING
      /* Otherwise this is a generic code; we should just lists all of
         these explicitly.  We forgot one.  */
      gcc_unreachable ();
#else
      /* In a release build, we want to degrade gracefully: better to
         generate incomplete debugging information than to crash.  */
      return NULL;
#endif
    }

  if (!ret && !list_ret)
    return 0;

  if (want_address == 2 && !have_address
      && (dwarf_version >= 4 || !dwarf_strict))
    {
      if (int_size_in_bytes (TREE_TYPE (loc)) > DWARF2_ADDR_SIZE)
        {
          expansion_failed (loc, NULL_RTX,
                            "DWARF address size mismatch");
          return 0;
        }
      if (ret)
        add_loc_descr (&ret, new_loc_descr (DW_OP_stack_value, 0, 0));
      else
        add_loc_descr_to_each (list_ret,
                               new_loc_descr (DW_OP_stack_value, 0, 0));
      have_address = 1;
    }
  /* Show if we can't fill the request for an address.  */
  if (want_address && !have_address)
    {
      expansion_failed (loc, NULL_RTX,
                        "Want address and only have value");
      return 0;
    }

  gcc_assert (!ret || !list_ret);

  /* If we've got an address and don't want one, dereference.  */
  if (!want_address && have_address)
    {
      HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (loc));

      if (size > DWARF2_ADDR_SIZE || size == -1)
        {
          expansion_failed (loc, NULL_RTX,
                            "DWARF address size mismatch");
          return 0;
        }
      else if (size == DWARF2_ADDR_SIZE)
        op = DW_OP_deref;
      else
        op = DW_OP_deref_size;

      if (ret)
        add_loc_descr (&ret, new_loc_descr (op, size, 0));
      else
        add_loc_descr_to_each (list_ret, new_loc_descr (op, size, 0));
    }
  if (ret)
    list_ret = new_loc_list (ret, NULL, NULL, NULL);

  return list_ret;
}

/* Same as above but return only single location expression.  */
static dw_loc_descr_ref
loc_descriptor_from_tree (tree loc, int want_address)
{
  dw_loc_list_ref ret = loc_list_from_tree (loc, want_address);
  if (!ret)
    return NULL;
  if (ret->dw_loc_next)
    {
      expansion_failed (loc, NULL_RTX,
                        "Location list where only loc descriptor needed");
      return NULL;
    }
  return ret->expr;
}

/* Given a value, round it up to the lowest multiple of `boundary'
   which is not less than the value itself.  */

static inline HOST_WIDE_INT
ceiling (HOST_WIDE_INT value, unsigned int boundary)
{
  return (((value + boundary - 1) / boundary) * boundary);
}

/* Given a pointer to what is assumed to be a FIELD_DECL node, return a
   pointer to the declared type for the relevant field variable, or return
   `integer_type_node' if the given node turns out to be an
   ERROR_MARK node.  */

static inline tree
field_type (const_tree decl)
{
  tree type;

  if (TREE_CODE (decl) == ERROR_MARK)
    return integer_type_node;

  type = DECL_BIT_FIELD_TYPE (decl);
  if (type == NULL_TREE)
    type = TREE_TYPE (decl);

  return type;
}

/* Given a pointer to a tree node, return the alignment in bits for
   it, or else return BITS_PER_WORD if the node actually turns out to
   be an ERROR_MARK node.  */

static inline unsigned
simple_type_align_in_bits (const_tree type)
{
  return (TREE_CODE (type) != ERROR_MARK) ? TYPE_ALIGN (type) : BITS_PER_WORD;
}

static inline unsigned
simple_decl_align_in_bits (const_tree decl)
{
  return (TREE_CODE (decl) != ERROR_MARK) ? DECL_ALIGN (decl) : BITS_PER_WORD;
}

/* Return the result of rounding T up to ALIGN.  */

static inline double_int
round_up_to_align (double_int t, unsigned int align)
{
  double_int alignd = uhwi_to_double_int (align);
  t = double_int_add (t, alignd);
  t = double_int_add (t, double_int_minus_one);
  t = double_int_div (t, alignd, true, TRUNC_DIV_EXPR);
  t = double_int_mul (t, alignd);
  return t;
}

/* Given a pointer to a FIELD_DECL, compute and return the byte offset of the
   lowest addressed byte of the "containing object" for the given FIELD_DECL,
   or return 0 if we are unable to determine what that offset is, either
   because the argument turns out to be a pointer to an ERROR_MARK node, or
   because the offset is actually variable.  (We can't handle the latter case
   just yet).  */

static HOST_WIDE_INT
field_byte_offset (const_tree decl)
{
  double_int object_offset_in_bits;
  double_int object_offset_in_bytes;
  double_int bitpos_int;

  if (TREE_CODE (decl) == ERROR_MARK)
    return 0;

  gcc_assert (TREE_CODE (decl) == FIELD_DECL);

  /* We cannot yet cope with fields whose positions are variable, so
     for now, when we see such things, we simply return 0.  Someday, we may
     be able to handle such cases, but it will be damn difficult.  */
  if (TREE_CODE (bit_position (decl)) != INTEGER_CST)
    return 0;

  bitpos_int = tree_to_double_int (bit_position (decl));

#ifdef PCC_BITFIELD_TYPE_MATTERS
  if (PCC_BITFIELD_TYPE_MATTERS)
    {
      tree type;
      tree field_size_tree;
      double_int deepest_bitpos;
      double_int field_size_in_bits;
      unsigned int type_align_in_bits;
      unsigned int decl_align_in_bits;
      double_int type_size_in_bits;

      type = field_type (decl);
      type_size_in_bits = double_int_type_size_in_bits (type);
      type_align_in_bits = simple_type_align_in_bits (type);

      field_size_tree = DECL_SIZE (decl);

      /* The size could be unspecified if there was an error, or for
         a flexible array member.  */
      if (!field_size_tree)
        field_size_tree = bitsize_zero_node;

      /* If the size of the field is not constant, use the type size.  */
      if (TREE_CODE (field_size_tree) == INTEGER_CST)
        field_size_in_bits = tree_to_double_int (field_size_tree);
      else
        field_size_in_bits = type_size_in_bits;

      decl_align_in_bits = simple_decl_align_in_bits (decl);

      /* The GCC front-end doesn't make any attempt to keep track of the
         starting bit offset (relative to the start of the containing
         structure type) of the hypothetical "containing object" for a
         bit-field.  Thus, when computing the byte offset value for the
         start of the "containing object" of a bit-field, we must deduce
         this information on our own. This can be rather tricky to do in
         some cases.  For example, handling the following structure type
         definition when compiling for an i386/i486 target (which only
         aligns long long's to 32-bit boundaries) can be very tricky:

         struct S { int field1; long long field2:31; };

         Fortunately, there is a simple rule-of-thumb which can be used
         in such cases.  When compiling for an i386/i486, GCC will
         allocate 8 bytes for the structure shown above.  It decides to
         do this based upon one simple rule for bit-field allocation.
         GCC allocates each "containing object" for each bit-field at
         the first (i.e. lowest addressed) legitimate alignment boundary
         (based upon the required minimum alignment for the declared
         type of the field) which it can possibly use, subject to the
         condition that there is still enough available space remaining
         in the containing object (when allocated at the selected point)
         to fully accommodate all of the bits of the bit-field itself.

         This simple rule makes it obvious why GCC allocates 8 bytes for
         each object of the structure type shown above.  When looking
         for a place to allocate the "containing object" for `field2',
         the compiler simply tries to allocate a 64-bit "containing
         object" at each successive 32-bit boundary (starting at zero)
         until it finds a place to allocate that 64- bit field such that
         at least 31 contiguous (and previously unallocated) bits remain
         within that selected 64 bit field.  (As it turns out, for the
         example above, the compiler finds it is OK to allocate the
         "containing object" 64-bit field at bit-offset zero within the
         structure type.)

         Here we attempt to work backwards from the limited set of facts
         we're given, and we try to deduce from those facts, where GCC
         must have believed that the containing object started (within
         the structure type). The value we deduce is then used (by the
         callers of this routine) to generate DW_AT_location and
         DW_AT_bit_offset attributes for fields (both bit-fields and, in
         the case of DW_AT_location, regular fields as well).  */

      /* Figure out the bit-distance from the start of the structure to
         the "deepest" bit of the bit-field.  */
      deepest_bitpos = double_int_add (bitpos_int, field_size_in_bits);

      /* This is the tricky part.  Use some fancy footwork to deduce
         where the lowest addressed bit of the containing object must
         be.  */
      object_offset_in_bits
        = double_int_sub (deepest_bitpos, type_size_in_bits);

      /* Round up to type_align by default.  This works best for
         bitfields.  */
      object_offset_in_bits
        = round_up_to_align (object_offset_in_bits, type_align_in_bits);

      if (double_int_ucmp (object_offset_in_bits, bitpos_int) > 0)
        {
          object_offset_in_bits
            = double_int_sub (deepest_bitpos, type_size_in_bits);

          /* Round up to decl_align instead.  */
          object_offset_in_bits
            = round_up_to_align (object_offset_in_bits, decl_align_in_bits);
        }
    }
  else
#endif /* PCC_BITFIELD_TYPE_MATTERS */
    object_offset_in_bits = bitpos_int;

  object_offset_in_bytes
    = double_int_div (object_offset_in_bits,
                      uhwi_to_double_int (BITS_PER_UNIT), true,
                      TRUNC_DIV_EXPR);
  return double_int_to_shwi (object_offset_in_bytes);
}
\f
/* The following routines define various Dwarf attributes and any data
   associated with them.  */

/* Add a location description attribute value to a DIE.

   This emits location attributes suitable for whole variables and
   whole parameters.  Note that the location attributes for struct fields are
   generated by the routine `data_member_location_attribute' below.  */

static inline void
add_AT_location_description (dw_die_ref die, enum dwarf_attribute attr_kind,
                             dw_loc_list_ref descr)
{
  if (descr == 0)
    return;
  if (single_element_loc_list_p (descr))
    add_AT_loc (die, attr_kind, descr->expr);
  else
    add_AT_loc_list (die, attr_kind, descr);
}

/* Add DW_AT_accessibility attribute to DIE if needed.  */

static void
add_accessibility_attribute (dw_die_ref die, tree decl)
{
  /* In DWARF3+ the default is DW_ACCESS_private only in DW_TAG_class_type
     children, otherwise the default is DW_ACCESS_public.  In DWARF2
     the default has always been DW_ACCESS_public.  */
  if (TREE_PROTECTED (decl))
    add_AT_unsigned (die, DW_AT_accessibility, DW_ACCESS_protected);
  else if (TREE_PRIVATE (decl))
    {
      if (dwarf_version == 2
          || die->die_parent == NULL
          || die->die_parent->die_tag != DW_TAG_class_type)
        add_AT_unsigned (die, DW_AT_accessibility, DW_ACCESS_private);
    }
  else if (dwarf_version > 2
           && die->die_parent
           && die->die_parent->die_tag == DW_TAG_class_type)
    add_AT_unsigned (die, DW_AT_accessibility, DW_ACCESS_public);
}

/* Attach the specialized form of location attribute used for data members of
   struct and union types.  In the special case of a FIELD_DECL node which
   represents a bit-field, the "offset" part of this special location
   descriptor must indicate the distance in bytes from the lowest-addressed
   byte of the containing struct or union type to the lowest-addressed byte of
   the "containing object" for the bit-field.  (See the `field_byte_offset'
   function above).

   For any given bit-field, the "containing object" is a hypothetical object
   (of some integral or enum type) within which the given bit-field lives.  The
   type of this hypothetical "containing object" is always the same as the
   declared type of the individual bit-field itself (for GCC anyway... the
   DWARF spec doesn't actually mandate this).  Note that it is the size (in
   bytes) of the hypothetical "containing object" which will be given in the
   DW_AT_byte_size attribute for this bit-field.  (See the
   `byte_size_attribute' function below.)  It is also used when calculating the
   value of the DW_AT_bit_offset attribute.  (See the `bit_offset_attribute'
   function below.)  */

static void
add_data_member_location_attribute (dw_die_ref die, tree decl)
{
  HOST_WIDE_INT offset;
  dw_loc_descr_ref loc_descr = 0;

  if (TREE_CODE (decl) == TREE_BINFO)
    {
      /* We're working on the TAG_inheritance for a base class.  */
      if (BINFO_VIRTUAL_P (decl) && is_cxx ())
        {
          /* For C++ virtual bases we can't just use BINFO_OFFSET, as they
             aren't at a fixed offset from all (sub)objects of the same
             type.  We need to extract the appropriate offset from our
             vtable.  The following dwarf expression means

               BaseAddr = ObAddr + *((*ObAddr) - Offset)

             This is specific to the V3 ABI, of course.  */

          dw_loc_descr_ref tmp;

          /* Make a copy of the object address.  */
          tmp = new_loc_descr (DW_OP_dup, 0, 0);
          add_loc_descr (&loc_descr, tmp);

          /* Extract the vtable address.  */
          tmp = new_loc_descr (DW_OP_deref, 0, 0);
          add_loc_descr (&loc_descr, tmp);

          /* Calculate the address of the offset.  */
          offset = tree_low_cst (BINFO_VPTR_FIELD (decl), 0);
          gcc_assert (offset < 0);

          tmp = int_loc_descriptor (-offset);
          add_loc_descr (&loc_descr, tmp);
          tmp = new_loc_descr (DW_OP_minus, 0, 0);
          add_loc_descr (&loc_descr, tmp);

          /* Extract the offset.  */
          tmp = new_loc_descr (DW_OP_deref, 0, 0);
          add_loc_descr (&loc_descr, tmp);

          /* Add it to the object address.  */
          tmp = new_loc_descr (DW_OP_plus, 0, 0);
          add_loc_descr (&loc_descr, tmp);
        }
      else
        offset = tree_low_cst (BINFO_OFFSET (decl), 0);
    }
  else
    offset = field_byte_offset (decl);

  if (! loc_descr)
    {
      if (dwarf_version > 2)
        {
          /* Don't need to output a location expression, just the constant. */
          if (offset < 0)
            add_AT_int (die, DW_AT_data_member_location, offset);
          else
            add_AT_unsigned (die, DW_AT_data_member_location, offset);
          return;
        }
      else
        {
          enum dwarf_location_atom op;

          /* The DWARF2 standard says that we should assume that the structure
             address is already on the stack, so we can specify a structure
             field address by using DW_OP_plus_uconst.  */

#ifdef MIPS_DEBUGGING_INFO
          /* ??? The SGI dwarf reader does not handle the DW_OP_plus_uconst
             operator correctly.  It works only if we leave the offset on the
             stack.  */
          op = DW_OP_constu;
#else
          op = DW_OP_plus_uconst;
#endif

          loc_descr = new_loc_descr (op, offset, 0);
        }
    }

  add_AT_loc (die, DW_AT_data_member_location, loc_descr);
}

/* Writes integer values to dw_vec_const array.  */

static void
insert_int (HOST_WIDE_INT val, unsigned int size, unsigned char *dest)
{
  while (size != 0)
    {
      *dest++ = val & 0xff;
      val >>= 8;
      --size;
    }
}

/* Reads integers from dw_vec_const array.  Inverse of insert_int.  */

static HOST_WIDE_INT
extract_int (const unsigned char *src, unsigned int size)
{
  HOST_WIDE_INT val = 0;

  src += size;
  while (size != 0)
    {
      val <<= 8;
      val |= *--src & 0xff;
      --size;
    }
  return val;
}

/* Writes double_int values to dw_vec_const array.  */

static void
insert_double (double_int val, unsigned char *dest)
{
  unsigned char *p0 = dest;
  unsigned char *p1 = dest + sizeof (HOST_WIDE_INT);

  if (WORDS_BIG_ENDIAN)
    {
      p0 = p1;
      p1 = dest;
    }

  insert_int ((HOST_WIDE_INT) val.low, sizeof (HOST_WIDE_INT), p0);
  insert_int ((HOST_WIDE_INT) val.high, sizeof (HOST_WIDE_INT), p1);
}

/* Writes floating point values to dw_vec_const array.  */

static void
insert_float (const_rtx rtl, unsigned char *array)
{
  REAL_VALUE_TYPE rv;
  long val[4];
  int i;

  REAL_VALUE_FROM_CONST_DOUBLE (rv, rtl);
  real_to_target (val, &rv, GET_MODE (rtl));

  /* real_to_target puts 32-bit pieces in each long.  Pack them.  */
  for (i = 0; i < GET_MODE_SIZE (GET_MODE (rtl)) / 4; i++)
    {
      insert_int (val[i], 4, array);
      array += 4;
    }
}

/* Attach a DW_AT_const_value attribute for a variable or a parameter which
   does not have a "location" either in memory or in a register.  These
   things can arise in GNU C when a constant is passed as an actual parameter
   to an inlined function.  They can also arise in C++ where declared
   constants do not necessarily get memory "homes".  */

static bool
add_const_value_attribute (dw_die_ref die, rtx rtl)
{
  switch (GET_CODE (rtl))
    {
    case CONST_INT:
      {
        HOST_WIDE_INT val = INTVAL (rtl);

        if (val < 0)
          add_AT_int (die, DW_AT_const_value, val);
        else
          add_AT_unsigned (die, DW_AT_const_value, (unsigned HOST_WIDE_INT) val);
      }
      return true;

    case CONST_DOUBLE:
      /* Note that a CONST_DOUBLE rtx could represent either an integer or a
         floating-point constant.  A CONST_DOUBLE is used whenever the
         constant requires more than one word in order to be adequately
         represented.  */
      {
        enum machine_mode mode = GET_MODE (rtl);

        if (SCALAR_FLOAT_MODE_P (mode))
          {
            unsigned int length = GET_MODE_SIZE (mode);
            unsigned char *array = (unsigned char *) ggc_alloc_atomic (length);

            insert_float (rtl, array);
            add_AT_vec (die, DW_AT_const_value, length / 4, 4, array);
          }
        else
          add_AT_double (die, DW_AT_const_value,
                         CONST_DOUBLE_HIGH (rtl), CONST_DOUBLE_LOW (rtl));
      }
      return true;

    case CONST_VECTOR:
      {
        enum machine_mode mode = GET_MODE (rtl);
        unsigned int elt_size = GET_MODE_UNIT_SIZE (mode);
        unsigned int length = CONST_VECTOR_NUNITS (rtl);
        unsigned char *array = (unsigned char *) ggc_alloc_atomic
          (length * elt_size);
        unsigned int i;
        unsigned char *p;

        switch (GET_MODE_CLASS (mode))
          {
          case MODE_VECTOR_INT:
            for (i = 0, p = array; i < length; i++, p += elt_size)
              {
                rtx elt = CONST_VECTOR_ELT (rtl, i);
                double_int val = rtx_to_double_int (elt);

                if (elt_size <= sizeof (HOST_WIDE_INT))
                  insert_int (double_int_to_shwi (val), elt_size, p);
                else
                  {
                    gcc_assert (elt_size == 2 * sizeof (HOST_WIDE_INT));
                    insert_double (val, p);
                  }
              }
            break;

          case MODE_VECTOR_FLOAT:
            for (i = 0, p = array; i < length; i++, p += elt_size)
              {
                rtx elt = CONST_VECTOR_ELT (rtl, i);
                insert_float (elt, p);
              }
            break;

          default:
            gcc_unreachable ();
          }

        add_AT_vec (die, DW_AT_const_value, length, elt_size, array);
      }
      return true;

    case CONST_STRING:
      if (dwarf_version >= 4 || !dwarf_strict)
        {
          dw_loc_descr_ref loc_result;
          resolve_one_addr (&rtl, NULL);
        rtl_addr:
          loc_result = new_loc_descr (DW_OP_addr, 0, 0);
          loc_result->dw_loc_oprnd1.val_class = dw_val_class_addr;
          loc_result->dw_loc_oprnd1.v.val_addr = rtl;
          add_loc_descr (&loc_result, new_loc_descr (DW_OP_stack_value, 0, 0));
          add_AT_loc (die, DW_AT_location, loc_result);
          VEC_safe_push (rtx, gc, used_rtx_array, rtl);
          return true;
        }
      return false;

    case CONST:
      if (CONSTANT_P (XEXP (rtl, 0)))
        return add_const_value_attribute (die, XEXP (rtl, 0));
      /* FALLTHROUGH */
    case SYMBOL_REF:
      if (!const_ok_for_output (rtl))
        return false;
    case LABEL_REF:
      if (dwarf_version >= 4 || !dwarf_strict)
        goto rtl_addr;
      return false;

    case PLUS:
      /* In cases where an inlined instance of an inline function is passed
         the address of an `auto' variable (which is local to the caller) we
         can get a situation where the DECL_RTL of the artificial local
         variable (for the inlining) which acts as a stand-in for the
         corresponding formal parameter (of the inline function) will look
         like (plus:SI (reg:SI FRAME_PTR) (const_int ...)).  This is not
         exactly a compile-time constant expression, but it isn't the address
         of the (artificial) local variable either.  Rather, it represents the
         *value* which the artificial local variable always has during its
         lifetime.  We currently have no way to represent such quasi-constant
         values in Dwarf, so for now we just punt and generate nothing.  */
      return false;

    case HIGH:
    case CONST_FIXED:
      return false;

    case MEM:
      if (GET_CODE (XEXP (rtl, 0)) == CONST_STRING
          && MEM_READONLY_P (rtl)
          && GET_MODE (rtl) == BLKmode)
        {
          add_AT_string (die, DW_AT_const_value, XSTR (XEXP (rtl, 0), 0));
          return true;
        }
      return false;

    default:
      /* No other kinds of rtx should be possible here.  */
      gcc_unreachable ();
    }
  return false;
}

/* Determine whether the evaluation of EXPR references any variables
   or functions which aren't otherwise used (and therefore may not be
   output).  */
static tree
reference_to_unused (tree * tp, int * walk_subtrees,
                     void * data ATTRIBUTE_UNUSED)
{
  if (! EXPR_P (*tp) && ! CONSTANT_CLASS_P (*tp))
    *walk_subtrees = 0;

  if (DECL_P (*tp) && ! TREE_PUBLIC (*tp) && ! TREE_USED (*tp)
      && ! TREE_ASM_WRITTEN (*tp))
    return *tp;
  /* ???  The C++ FE emits debug information for using decls, so
     putting gcc_unreachable here falls over.  See PR31899.  For now
     be conservative.  */
  else if (!cgraph_global_info_ready
           && (TREE_CODE (*tp) == VAR_DECL || TREE_CODE (*tp) == FUNCTION_DECL))
    return *tp;
  else if (TREE_CODE (*tp) == VAR_DECL)
    {
      struct varpool_node *node = varpool_get_node (*tp);
      if (!node || !node->needed)
        return *tp;
    }
  else if (TREE_CODE (*tp) == FUNCTION_DECL
           && (!DECL_EXTERNAL (*tp) || DECL_DECLARED_INLINE_P (*tp)))
    {
      /* The call graph machinery must have finished analyzing,
         optimizing and gimplifying the CU by now.
         So if *TP has no call graph node associated
         to it, it means *TP will not be emitted.  */
      if (!cgraph_get_node (*tp))
        return *tp;
    }
  else if (TREE_CODE (*tp) == STRING_CST && !TREE_ASM_WRITTEN (*tp))
    return *tp;

  return NULL_TREE;
}

/* Generate an RTL constant from a decl initializer INIT with decl type TYPE,
   for use in a later add_const_value_attribute call.  */

static rtx
rtl_for_decl_init (tree init, tree type)
{
  rtx rtl = NULL_RTX;

  STRIP_NOPS (init);

  /* If a variable is initialized with a string constant without embedded
     zeros, build CONST_STRING.  */
  if (TREE_CODE (init) == STRING_CST && TREE_CODE (type) == ARRAY_TYPE)
    {
      tree enttype = TREE_TYPE (type);
      tree domain = TYPE_DOMAIN (type);
      enum machine_mode mode = TYPE_MODE (enttype);

      if (GET_MODE_CLASS (mode) == MODE_INT && GET_MODE_SIZE (mode) == 1
          && domain
          && integer_zerop (TYPE_MIN_VALUE (domain))
          && compare_tree_int (TYPE_MAX_VALUE (domain),
                               TREE_STRING_LENGTH (init) - 1) == 0
          && ((size_t) TREE_STRING_LENGTH (init)
              == strlen (TREE_STRING_POINTER (init)) + 1))
        {
          rtl = gen_rtx_CONST_STRING (VOIDmode,
                                      ggc_strdup (TREE_STRING_POINTER (init)));
          rtl = gen_rtx_MEM (BLKmode, rtl);
          MEM_READONLY_P (rtl) = 1;
        }
    }
  /* Other aggregates, and complex values, could be represented using
     CONCAT: FIXME!  */
  else if (AGGREGATE_TYPE_P (type)
           || (TREE_CODE (init) == VIEW_CONVERT_EXPR
               && AGGREGATE_TYPE_P (TREE_TYPE (TREE_OPERAND (init, 0))))
           || TREE_CODE (type) == COMPLEX_TYPE)
    ;
  /* Vectors only work if their mode is supported by the target.
     FIXME: generic vectors ought to work too.  */
  else if (TREE_CODE (type) == VECTOR_TYPE
           && !VECTOR_MODE_P (TYPE_MODE (type)))
    ;
  /* If the initializer is something that we know will expand into an
     immediate RTL constant, expand it now.  We must be careful not to
     reference variables which won't be output.  */
  else if (initializer_constant_valid_p (init, type)
           && ! walk_tree (&init, reference_to_unused, NULL, NULL))
    {
      /* Convert vector CONSTRUCTOR initializers to VECTOR_CST if
         possible.  */
      if (TREE_CODE (type) == VECTOR_TYPE)
        switch (TREE_CODE (init))
          {
          case VECTOR_CST:
            break;
          case CONSTRUCTOR:
            if (TREE_CONSTANT (init))
              {
                VEC(constructor_elt,gc) *elts = CONSTRUCTOR_ELTS (init);
                bool constant_p = true;
                tree value;
                unsigned HOST_WIDE_INT ix;

                /* Even when ctor is constant, it might contain non-*_CST
                   elements (e.g. { 1.0/0.0 - 1.0/0.0, 0.0 }) and those don't
                   belong into VECTOR_CST nodes.  */
                FOR_EACH_CONSTRUCTOR_VALUE (elts, ix, value)
                  if (!CONSTANT_CLASS_P (value))
                    {
                      constant_p = false;
                      break;
                    }

                if (constant_p)
                  {
                    init = build_vector_from_ctor (type, elts);
                    break;
                  }
              }
            /* FALLTHRU */

          default:
            return NULL;
          }

      rtl = expand_expr (init, NULL_RTX, VOIDmode, EXPAND_INITIALIZER);

      /* If expand_expr returns a MEM, it wasn't immediate.  */
      gcc_assert (!rtl || !MEM_P (rtl));
    }

  return rtl;
}

/* Generate RTL for the variable DECL to represent its location.  */

static rtx
rtl_for_decl_location (tree decl)
{
  rtx rtl;

  /* Here we have to decide where we are going to say the parameter "lives"
     (as far as the debugger is concerned).  We only have a couple of
     choices.  GCC provides us with DECL_RTL and with DECL_INCOMING_RTL.

     DECL_RTL normally indicates where the parameter lives during most of the
     activation of the function.  If optimization is enabled however, this
     could be either NULL or else a pseudo-reg.  Both of those cases indicate
     that the parameter doesn't really live anywhere (as far as the code
     generation parts of GCC are concerned) during most of the function's
     activation.  That will happen (for example) if the parameter is never
     referenced within the function.

     We could just generate a location descriptor here for all non-NULL
     non-pseudo values of DECL_RTL and ignore all of the rest, but we can be
     a little nicer than that if we also consider DECL_INCOMING_RTL in cases
     where DECL_RTL is NULL or is a pseudo-reg.

     Note however that we can only get away with using DECL_INCOMING_RTL as
     a backup substitute for DECL_RTL in certain limited cases.  In cases
     where DECL_ARG_TYPE (decl) indicates the same type as TREE_TYPE (decl),
     we can be sure that the parameter was passed using the same type as it is
     declared to have within the function, and that its DECL_INCOMING_RTL
     points us to a place where a value of that type is passed.

     In cases where DECL_ARG_TYPE (decl) and TREE_TYPE (decl) are different,
     we cannot (in general) use DECL_INCOMING_RTL as a substitute for DECL_RTL
     because in these cases DECL_INCOMING_RTL points us to a value of some
     type which is *different* from the type of the parameter itself.  Thus,
     if we tried to use DECL_INCOMING_RTL to generate a location attribute in
     such cases, the debugger would end up (for example) trying to fetch a
     `float' from a place which actually contains the first part of a
     `double'.  That would lead to really incorrect and confusing
     output at debug-time.

     So, in general, we *do not* use DECL_INCOMING_RTL as a backup for DECL_RTL
     in cases where DECL_ARG_TYPE (decl) != TREE_TYPE (decl).  There
     are a couple of exceptions however.  On little-endian machines we can
     get away with using DECL_INCOMING_RTL even when DECL_ARG_TYPE (decl) is
     not the same as TREE_TYPE (decl), but only when DECL_ARG_TYPE (decl) is
     an integral type that is smaller than TREE_TYPE (decl). These cases arise
     when (on a little-endian machine) a non-prototyped function has a
     parameter declared to be of type `short' or `char'.  In such cases,
     TREE_TYPE (decl) will be `short' or `char', DECL_ARG_TYPE (decl) will
     be `int', and DECL_INCOMING_RTL will point to the lowest-order byte of the
     passed `int' value.  If the debugger then uses that address to fetch
     a `short' or a `char' (on a little-endian machine) the result will be
     the correct data, so we allow for such exceptional cases below.

     Note that our goal here is to describe the place where the given formal
     parameter lives during most of the function's activation (i.e. between the
     end of the prologue and the start of the epilogue).  We'll do that as best
     as we can. Note however that if the given formal parameter is modified
     sometime during the execution of the function, then a stack backtrace (at
     debug-time) will show the function as having been called with the *new*
     value rather than the value which was originally passed in.  This happens
     rarely enough that it is not a major problem, but it *is* a problem, and
     I'd like to fix it.

     A future version of dwarf2out.c may generate two additional attributes for
     any given DW_TAG_formal_parameter DIE which will describe the "passed
     type" and the "passed location" for the given formal parameter in addition
     to the attributes we now generate to indicate the "declared type" and the
     "active location" for each parameter.  This additional set of attributes
     could be used by debuggers for stack backtraces. Separately, note that
     sometimes DECL_RTL can be NULL and DECL_INCOMING_RTL can be NULL also.
     This happens (for example) for inlined-instances of inline function formal
     parameters which are never referenced.  This really shouldn't be
     happening.  All PARM_DECL nodes should get valid non-NULL
     DECL_INCOMING_RTL values.  FIXME.  */

  /* Use DECL_RTL as the "location" unless we find something better.  */
  rtl = DECL_RTL_IF_SET (decl);

  /* When generating abstract instances, ignore everything except
     constants, symbols living in memory, and symbols living in
     fixed registers.  */
  if (! reload_completed)
    {
      if (rtl
          && (CONSTANT_P (rtl)
              || (MEM_P (rtl)
                  && CONSTANT_P (XEXP (rtl, 0)))
              || (REG_P (rtl)
                  && TREE_CODE (decl) == VAR_DECL
                  && TREE_STATIC (decl))))
        {
          rtl = targetm.delegitimize_address (rtl);
          return rtl;
        }
      rtl = NULL_RTX;
    }
  else if (TREE_CODE (decl) == PARM_DECL)
    {
      if (rtl == NULL_RTX || is_pseudo_reg (rtl))
        {
          tree declared_type = TREE_TYPE (decl);
          tree passed_type = DECL_ARG_TYPE (decl);
          enum machine_mode dmode = TYPE_MODE (declared_type);
          enum machine_mode pmode = TYPE_MODE (passed_type);

          /* This decl represents a formal parameter which was optimized out.
             Note that DECL_INCOMING_RTL may be NULL in here, but we handle
             all cases where (rtl == NULL_RTX) just below.  */
          if (dmode == pmode)
            rtl = DECL_INCOMING_RTL (decl);
          else if (SCALAR_INT_MODE_P (dmode)
                   && GET_MODE_SIZE (dmode) <= GET_MODE_SIZE (pmode)
                   && DECL_INCOMING_RTL (decl))
            {
              rtx inc = DECL_INCOMING_RTL (decl);
              if (REG_P (inc))
                rtl = inc;
              else if (MEM_P (inc))
                {
                  if (BYTES_BIG_ENDIAN)
                    rtl = adjust_address_nv (inc, dmode,
                                             GET_MODE_SIZE (pmode)
                                             - GET_MODE_SIZE (dmode));
                  else
                    rtl = inc;
                }
            }
        }

      /* If the parm was passed in registers, but lives on the stack, then
         make a big endian correction if the mode of the type of the
         parameter is not the same as the mode of the rtl.  */
      /* ??? This is the same series of checks that are made in dbxout.c before
         we reach the big endian correction code there.  It isn't clear if all
         of these checks are necessary here, but keeping them all is the safe
         thing to do.  */
      else if (MEM_P (rtl)
               && XEXP (rtl, 0) != const0_rtx
               && ! CONSTANT_P (XEXP (rtl, 0))
               /* Not passed in memory.  */
               && !MEM_P (DECL_INCOMING_RTL (decl))
               /* Not passed by invisible reference.  */
               && (!REG_P (XEXP (rtl, 0))
                   || REGNO (XEXP (rtl, 0)) == HARD_FRAME_POINTER_REGNUM
                   || REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM
#if !HARD_FRAME_POINTER_IS_ARG_POINTER
                   || REGNO (XEXP (rtl, 0)) == ARG_POINTER_REGNUM
#endif
                     )
               /* Big endian correction check.  */
               && BYTES_BIG_ENDIAN
               && TYPE_MODE (TREE_TYPE (decl)) != GET_MODE (rtl)
               && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (decl)))
                   < UNITS_PER_WORD))
        {
          int offset = (UNITS_PER_WORD
                        - GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (decl))));

          rtl = gen_rtx_MEM (TYPE_MODE (TREE_TYPE (decl)),
                             plus_constant (XEXP (rtl, 0), offset));
        }
    }
  else if (TREE_CODE (decl) == VAR_DECL
           && rtl
           && MEM_P (rtl)
           && GET_MODE (rtl) != TYPE_MODE (TREE_TYPE (decl))
           && BYTES_BIG_ENDIAN)
    {
      int rsize = GET_MODE_SIZE (GET_MODE (rtl));
      int dsize = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (decl)));

      /* If a variable is declared "register" yet is smaller than
         a register, then if we store the variable to memory, it
         looks like we're storing a register-sized value, when in
         fact we are not.  We need to adjust the offset of the
         storage location to reflect the actual value's bytes,
         else gdb will not be able to display it.  */
      if (rsize > dsize)
        rtl = gen_rtx_MEM (TYPE_MODE (TREE_TYPE (decl)),
                           plus_constant (XEXP (rtl, 0), rsize-dsize));
    }

  /* A variable with no DECL_RTL but a DECL_INITIAL is a compile-time constant,
     and will have been substituted directly into all expressions that use it.
     C does not have such a concept, but C++ and other languages do.  */
  if (!rtl && TREE_CODE (decl) == VAR_DECL && DECL_INITIAL (decl))
    rtl = rtl_for_decl_init (DECL_INITIAL (decl), TREE_TYPE (decl));

  if (rtl)
    rtl = targetm.delegitimize_address (rtl);

  /* If we don't look past the constant pool, we risk emitting a
     reference to a constant pool entry that isn't referenced from
     code, and thus is not emitted.  */
  if (rtl)
    rtl = avoid_constant_pool_reference (rtl);

  /* Try harder to get a rtl.  If this symbol ends up not being emitted
     in the current CU, resolve_addr will remove the expression referencing
     it.  */
  if (rtl == NULL_RTX
      && TREE_CODE (decl) == VAR_DECL
      && !DECL_EXTERNAL (decl)
      && TREE_STATIC (decl)
      && DECL_NAME (decl)
      && !DECL_HARD_REGISTER (decl)
      && DECL_MODE (decl) != VOIDmode)
    {
      rtl = make_decl_rtl_for_debug (decl);
      if (!MEM_P (rtl)
          || GET_CODE (XEXP (rtl, 0)) != SYMBOL_REF
          || SYMBOL_REF_DECL (XEXP (rtl, 0)) != decl)
        rtl = NULL_RTX;
    }

  return rtl;
}

/* Check whether decl is a Fortran COMMON symbol.  If not, NULL_TREE is
   returned.  If so, the decl for the COMMON block is returned, and the
   value is the offset into the common block for the symbol.  */

static tree
fortran_common (tree decl, HOST_WIDE_INT *value)
{
  tree val_expr, cvar;
  enum machine_mode mode;
  HOST_WIDE_INT bitsize, bitpos;
  tree offset;
  int volatilep = 0, unsignedp = 0;

  /* If the decl isn't a VAR_DECL, or if it isn't static, or if
     it does not have a value (the offset into the common area), or if it
     is thread local (as opposed to global) then it isn't common, and shouldn't
     be handled as such.  */
  if (TREE_CODE (decl) != VAR_DECL
      || !TREE_STATIC (decl)
      || !DECL_HAS_VALUE_EXPR_P (decl)
      || !is_fortran ())
    return NULL_TREE;

  val_expr = DECL_VALUE_EXPR (decl);
  if (TREE_CODE (val_expr) != COMPONENT_REF)
    return NULL_TREE;

  cvar = get_inner_reference (val_expr, &bitsize, &bitpos, &offset,
                              &mode, &unsignedp, &volatilep, true);

  if (cvar == NULL_TREE
      || TREE_CODE (cvar) != VAR_DECL
      || DECL_ARTIFICIAL (cvar)
      || !TREE_PUBLIC (cvar))
    return NULL_TREE;

  *value = 0;
  if (offset != NULL)
    {
      if (!host_integerp (offset, 0))
        return NULL_TREE;
      *value = tree_low_cst (offset, 0);
    }
  if (bitpos != 0)
    *value += bitpos / BITS_PER_UNIT;

  return cvar;
}

/* Generate *either* a DW_AT_location attribute or else a DW_AT_const_value
   data attribute for a variable or a parameter.  We generate the
   DW_AT_const_value attribute only in those cases where the given variable
   or parameter does not have a true "location" either in memory or in a
   register.  This can happen (for example) when a constant is passed as an
   actual argument in a call to an inline function.  (It's possible that
   these things can crop up in other ways also.)  Note that one type of
   constant value which can be passed into an inlined function is a constant
   pointer.  This can happen for example if an actual argument in an inlined
   function call evaluates to a compile-time constant address.  */

static bool
add_location_or_const_value_attribute (dw_die_ref die, tree decl,
                                       enum dwarf_attribute attr)
{
  rtx rtl;
  dw_loc_list_ref list;
  var_loc_list *loc_list;

  if (TREE_CODE (decl) == ERROR_MARK)
    return false;

  gcc_assert (TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL
              || TREE_CODE (decl) == RESULT_DECL);

  /* Try to get some constant RTL for this decl, and use that as the value of
     the location.  */

  rtl = rtl_for_decl_location (decl);
  if (rtl && (CONSTANT_P (rtl) || GET_CODE (rtl) == CONST_STRING)
      && add_const_value_attribute (die, rtl))
    return true;

  /* See if we have single element location list that is equivalent to
     a constant value.  That way we are better to use add_const_value_attribute
     rather than expanding constant value equivalent.  */
  loc_list = lookup_decl_loc (decl);
  if (loc_list
      && loc_list->first
      && loc_list->first->next == NULL
      && NOTE_P (loc_list->first->loc)
      && NOTE_VAR_LOCATION (loc_list->first->loc)
      && NOTE_VAR_LOCATION_LOC (loc_list->first->loc))
    {
      struct var_loc_node *node;

      node = loc_list->first;
      rtl = NOTE_VAR_LOCATION_LOC (node->loc);
      if (GET_CODE (rtl) == EXPR_LIST)
        rtl = XEXP (rtl, 0);
      if ((CONSTANT_P (rtl) || GET_CODE (rtl) == CONST_STRING)
          && add_const_value_attribute (die, rtl))
         return true;
    }
  list = loc_list_from_tree (decl, decl_by_reference_p (decl) ? 0 : 2);
  if (list)
    {
      add_AT_location_description (die, attr, list);
      return true;
    }
  /* None of that worked, so it must not really have a location;
     try adding a constant value attribute from the DECL_INITIAL.  */
  return tree_add_const_value_attribute_for_decl (die, decl);
}

/* Add VARIABLE and DIE into deferred locations list.  */

static void
defer_location (tree variable, dw_die_ref die)
{
  deferred_locations entry;
  entry.variable = variable;
  entry.die = die;
  VEC_safe_push (deferred_locations, gc, deferred_locations_list, &entry);
}

/* Helper function for tree_add_const_value_attribute.  Natively encode
   initializer INIT into an array.  Return true if successful.  */

static bool
native_encode_initializer (tree init, unsigned char *array, int size)
{
  tree type;

  if (init == NULL_TREE)
    return false;

  STRIP_NOPS (init);
  switch (TREE_CODE (init))
    {
    case STRING_CST:
      type = TREE_TYPE (init);
      if (TREE_CODE (type) == ARRAY_TYPE)
        {
          tree enttype = TREE_TYPE (type);
          enum machine_mode mode = TYPE_MODE (enttype);

          if (GET_MODE_CLASS (mode) != MODE_INT || GET_MODE_SIZE (mode) != 1)
            return false;
          if (int_size_in_bytes (type) != size)
            return false;
          if (size > TREE_STRING_LENGTH (init))
            {
              memcpy (array, TREE_STRING_POINTER (init),
                      TREE_STRING_LENGTH (init));
              memset (array + TREE_STRING_LENGTH (init),
                      '\0', size - TREE_STRING_LENGTH (init));
            }
          else
            memcpy (array, TREE_STRING_POINTER (init), size);
          return true;
        }
      return false;
    case CONSTRUCTOR:
      type = TREE_TYPE (init);
      if (int_size_in_bytes (type) != size)
        return false;
      if (TREE_CODE (type) == ARRAY_TYPE)
        {
          HOST_WIDE_INT min_index;
          unsigned HOST_WIDE_INT cnt;
          int curpos = 0, fieldsize;
          constructor_elt *ce;

          if (TYPE_DOMAIN (type) == NULL_TREE
              || !host_integerp (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0))
            return false;

          fieldsize = int_size_in_bytes (TREE_TYPE (type));
          if (fieldsize <= 0)
            return false;

          min_index = tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0);
          memset (array, '\0', size);
          FOR_EACH_VEC_ELT (constructor_elt, CONSTRUCTOR_ELTS (init), cnt, ce)
            {
              tree val = ce->value;
              tree index = ce->index;
              int pos = curpos;
              if (index && TREE_CODE (index) == RANGE_EXPR)
                pos = (tree_low_cst (TREE_OPERAND (index, 0), 0) - min_index)
                      * fieldsize;
              else if (index)
                pos = (tree_low_cst (index, 0) - min_index) * fieldsize;

              if (val)
                {
                  STRIP_NOPS (val);
                  if (!native_encode_initializer (val, array + pos, fieldsize))
                    return false;
                }
              curpos = pos + fieldsize;
              if (index && TREE_CODE (index) == RANGE_EXPR)
                {
                  int count = tree_low_cst (TREE_OPERAND (index, 1), 0)
                              - tree_low_cst (TREE_OPERAND (index, 0), 0);
                  while (count > 0)
                    {
                      if (val)
                        memcpy (array + curpos, array + pos, fieldsize);
                      curpos += fieldsize;
                    }
                }
              gcc_assert (curpos <= size);
            }
          return true;
        }
      else if (TREE_CODE (type) == RECORD_TYPE
               || TREE_CODE (type) == UNION_TYPE)
        {
          tree field = NULL_TREE;
          unsigned HOST_WIDE_INT cnt;
          constructor_elt *ce;

          if (int_size_in_bytes (type) != size)
            return false;

          if (TREE_CODE (type) == RECORD_TYPE)
            field = TYPE_FIELDS (type);

          FOR_EACH_VEC_ELT (constructor_elt, CONSTRUCTOR_ELTS (init), cnt, ce)
            {
              tree val = ce->value;
              int pos, fieldsize;

              if (ce->index != 0)
                field = ce->index;

              if (val)
                STRIP_NOPS (val);

              if (field == NULL_TREE || DECL_BIT_FIELD (field))
                return false;

              if (TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE
                  && TYPE_DOMAIN (TREE_TYPE (field))
                  && ! TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (field))))
                return false;
              else if (DECL_SIZE_UNIT (field) == NULL_TREE
                       || !host_integerp (DECL_SIZE_UNIT (field), 0))
                return false;
              fieldsize = tree_low_cst (DECL_SIZE_UNIT (field), 0);
              pos = int_byte_position (field);
              gcc_assert (pos + fieldsize <= size);
              if (val
                  && !native_encode_initializer (val, array + pos, fieldsize))
                return false;
            }
          return true;
        }
      return false;
    case VIEW_CONVERT_EXPR:
    case NON_LVALUE_EXPR:
      return native_encode_initializer (TREE_OPERAND (init, 0), array, size);
    default:
      return native_encode_expr (init, array, size) == size;
    }
}

/* Attach a DW_AT_const_value attribute to DIE. The value of the
   attribute is the const value T.  */

static bool
tree_add_const_value_attribute (dw_die_ref die, tree t)
{
  tree init;
  tree type = TREE_TYPE (t);
  rtx rtl;

  if (!t || !TREE_TYPE (t) || TREE_TYPE (t) == error_mark_node)
    return false;

  init = t;
  gcc_assert (!DECL_P (init));

  rtl = rtl_for_decl_init (init, type);
  if (rtl)
    return add_const_value_attribute (die, rtl);
  /* If the host and target are sane, try harder.  */
  else if (CHAR_BIT == 8 && BITS_PER_UNIT == 8
           && initializer_constant_valid_p (init, type))
    {
      HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (init));
      if (size > 0 && (int) size == size)
        {
          unsigned char *array = (unsigned char *)
            ggc_alloc_cleared_atomic (size);

          if (native_encode_initializer (init, array, size))
            {
              add_AT_vec (die, DW_AT_const_value, size, 1, array);
              return true;
            }
        }
    }
  return false;
}

/* Attach a DW_AT_const_value attribute to VAR_DIE. The value of the
   attribute is the const value of T, where T is an integral constant
   variable with static storage duration
   (so it can't be a PARM_DECL or a RESULT_DECL).  */

static bool
tree_add_const_value_attribute_for_decl (dw_die_ref var_die, tree decl)
{

  if (!decl
      || (TREE_CODE (decl) != VAR_DECL
          && TREE_CODE (decl) != CONST_DECL))
    return false;

    if (TREE_READONLY (decl)
        && ! TREE_THIS_VOLATILE (decl)
        && DECL_INITIAL (decl))
      /* OK */;
    else
      return false;

  /* Don't add DW_AT_const_value if abstract origin already has one.  */
  if (get_AT (var_die, DW_AT_const_value))
    return false;

  return tree_add_const_value_attribute (var_die, DECL_INITIAL (decl));
}

/* Convert the CFI instructions for the current function into a
   location list.  This is used for DW_AT_frame_base when we targeting
   a dwarf2 consumer that does not support the dwarf3
   DW_OP_call_frame_cfa.  OFFSET is a constant to be added to all CFA
   expressions.  */

static dw_loc_list_ref
convert_cfa_to_fb_loc_list (HOST_WIDE_INT offset)
{
  dw_fde_ref fde;
  dw_loc_list_ref list, *list_tail;
  dw_cfi_ref cfi;
  dw_cfa_location last_cfa, next_cfa;
  const char *start_label, *last_label, *section;
  dw_cfa_location remember;

  fde = current_fde ();
  gcc_assert (fde != NULL);

  section = secname_for_decl (current_function_decl);
  list_tail = &list;
  list = NULL;

  memset (&next_cfa, 0, sizeof (next_cfa));
  next_cfa.reg = INVALID_REGNUM;
  remember = next_cfa;

  start_label = fde->dw_fde_begin;

  /* ??? Bald assumption that the CIE opcode list does not contain
     advance opcodes.  */
  for (cfi = cie_cfi_head; cfi; cfi = cfi->dw_cfi_next)
    lookup_cfa_1 (cfi, &next_cfa, &remember);

  last_cfa = next_cfa;
  last_label = start_label;

  for (cfi = fde->dw_fde_cfi; cfi; cfi = cfi->dw_cfi_next)
    switch (cfi->dw_cfi_opc)
      {
      case DW_CFA_set_loc:
      case DW_CFA_advance_loc1:
      case DW_CFA_advance_loc2:
      case DW_CFA_advance_loc4:
        if (!cfa_equal_p (&last_cfa, &next_cfa))
          {
            *list_tail = new_loc_list (build_cfa_loc (&last_cfa, offset),
                                       start_label, last_label, section);

            list_tail = &(*list_tail)->dw_loc_next;
            last_cfa = next_cfa;
            start_label = last_label;
          }
        last_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
        break;

      case DW_CFA_advance_loc:
        /* The encoding is complex enough that we should never emit this.  */
        gcc_unreachable ();

      default:
        lookup_cfa_1 (cfi, &next_cfa, &remember);
        break;
      }

  if (!cfa_equal_p (&last_cfa, &next_cfa))
    {
      *list_tail = new_loc_list (build_cfa_loc (&last_cfa, offset),
                                 start_label, last_label, section);
      list_tail = &(*list_tail)->dw_loc_next;
      start_label = last_label;
    }

  *list_tail = new_loc_list (build_cfa_loc (&next_cfa, offset),
                             start_label, fde->dw_fde_end, section);

  if (list && list->dw_loc_next)
    gen_llsym (list);

  return list;
}

/* Compute a displacement from the "steady-state frame pointer" to the
   frame base (often the same as the CFA), and store it in
   frame_pointer_fb_offset.  OFFSET is added to the displacement
   before the latter is negated.  */

static void
compute_frame_pointer_to_fb_displacement (HOST_WIDE_INT offset)
{
  rtx reg, elim;

#ifdef FRAME_POINTER_CFA_OFFSET
  reg = frame_pointer_rtx;
  offset += FRAME_POINTER_CFA_OFFSET (current_function_decl);
#else
  reg = arg_pointer_rtx;
  offset += ARG_POINTER_CFA_OFFSET (current_function_decl);
#endif

  elim = eliminate_regs (reg, VOIDmode, NULL_RTX);
  if (GET_CODE (elim) == PLUS)
    {
      offset += INTVAL (XEXP (elim, 1));
      elim = XEXP (elim, 0);
    }

  gcc_assert ((SUPPORTS_STACK_ALIGNMENT
               && (elim == hard_frame_pointer_rtx
                   || elim == stack_pointer_rtx))
              || elim == (frame_pointer_needed
                          ? hard_frame_pointer_rtx
                          : stack_pointer_rtx));

  frame_pointer_fb_offset = -offset;
}

/* Generate a DW_AT_name attribute given some string value to be included as
   the value of the attribute.  */

static void
add_name_attribute (dw_die_ref die, const char *name_string)
{
  if (name_string != NULL && *name_string != 0)
    {
      if (demangle_name_func)
        name_string = (*demangle_name_func) (name_string);

      add_AT_string (die, DW_AT_name, name_string);
    }
}

/* Generate a DW_AT_comp_dir attribute for DIE.  */

static void
add_comp_dir_attribute (dw_die_ref die)
{
  const char *wd = get_src_pwd ();
  char *wd1;

  if (wd == NULL)
    return;

  if (DWARF2_DIR_SHOULD_END_WITH_SEPARATOR)
    {
      int wdlen;

      wdlen = strlen (wd);
      wd1 = (char *) ggc_alloc_atomic (wdlen + 2);
      strcpy (wd1, wd);
      wd1 [wdlen] = DIR_SEPARATOR;
      wd1 [wdlen + 1] = 0;
      wd = wd1;
    }

    add_AT_string (die, DW_AT_comp_dir, remap_debug_filename (wd));
}

/* Return the default for DW_AT_lower_bound, or -1 if there is not any
   default.  */

static int
lower_bound_default (void)
{
  switch (get_AT_unsigned (comp_unit_die (), DW_AT_language))
    {
    case DW_LANG_C:
    case DW_LANG_C89:
    case DW_LANG_C99:
    case DW_LANG_C_plus_plus:
    case DW_LANG_ObjC:
    case DW_LANG_ObjC_plus_plus:
    case DW_LANG_Java:
      return 0;
    case DW_LANG_Fortran77:
    case DW_LANG_Fortran90:
    case DW_LANG_Fortran95:
      return 1;
    case DW_LANG_UPC:
    case DW_LANG_D:
    case DW_LANG_Python:
      return dwarf_version >= 4 ? 0 : -1;
    case DW_LANG_Ada95:
    case DW_LANG_Ada83:
    case DW_LANG_Cobol74:
    case DW_LANG_Cobol85:
    case DW_LANG_Pascal83:
    case DW_LANG_Modula2:
    case DW_LANG_PLI:
      return dwarf_version >= 4 ? 1 : -1;
    default:
      return -1;
    }
}

/* Given a tree node describing an array bound (either lower or upper) output
   a representation for that bound.  */

static void
add_bound_info (dw_die_ref subrange_die, enum dwarf_attribute bound_attr, tree bound)
{
  switch (TREE_CODE (bound))
    {
    case ERROR_MARK:
      return;

    /* All fixed-bounds are represented by INTEGER_CST nodes.  */
    case INTEGER_CST:
      {
        unsigned int prec = simple_type_size_in_bits (TREE_TYPE (bound));
        int dflt;

        /* Use the default if possible.  */
        if (bound_attr == DW_AT_lower_bound
            && host_integerp (bound, 0)
            && (dflt = lower_bound_default ()) != -1
            && tree_low_cst (bound, 0) == dflt)
          ;

        /* Otherwise represent the bound as an unsigned value with the
           precision of its type.  The precision and signedness of the
           type will be necessary to re-interpret it unambiguously.  */
        else if (prec < HOST_BITS_PER_WIDE_INT)
          {
            unsigned HOST_WIDE_INT mask
              = ((unsigned HOST_WIDE_INT) 1 << prec) - 1;
            add_AT_unsigned (subrange_die, bound_attr,
                             TREE_INT_CST_LOW (bound) & mask);
          }
        else if (prec == HOST_BITS_PER_WIDE_INT
                 || TREE_INT_CST_HIGH (bound) == 0)
          add_AT_unsigned (subrange_die, bound_attr,
                           TREE_INT_CST_LOW (bound));
        else
          add_AT_double (subrange_die, bound_attr, TREE_INT_CST_HIGH (bound),
                         TREE_INT_CST_LOW (bound));
      }
      break;

    CASE_CONVERT:
    case VIEW_CONVERT_EXPR:
      add_bound_info (subrange_die, bound_attr, TREE_OPERAND (bound, 0));
      break;

    case SAVE_EXPR:
      break;

    case VAR_DECL:
    case PARM_DECL:
    case RESULT_DECL:
      {
        dw_die_ref decl_die = lookup_decl_die (bound);

        /* ??? Can this happen, or should the variable have been bound
           first?  Probably it can, since I imagine that we try to create
           the types of parameters in the order in which they exist in
           the list, and won't have created a forward reference to a
           later parameter.  */
        if (decl_die != NULL)
          {
            add_AT_die_ref (subrange_die, bound_attr, decl_die);
            break;
          }
      }
      /* FALLTHRU */

    default:
      {
        /* Otherwise try to create a stack operation procedure to
           evaluate the value of the array bound.  */

        dw_die_ref ctx, decl_die;
        dw_loc_list_ref list;

        list = loc_list_from_tree (bound, 2);
        if (list == NULL || single_element_loc_list_p (list))
          {
            /* If DW_AT_*bound is not a reference nor constant, it is
               a DWARF expression rather than location description.
               For that loc_list_from_tree (bound, 0) is needed.
               If that fails to give a single element list,
               fall back to outputting this as a reference anyway.  */
            dw_loc_list_ref list2 = loc_list_from_tree (bound, 0);
            if (list2 && single_element_loc_list_p (list2))
              {
                add_AT_loc (subrange_die, bound_attr, list2->expr);
                break;
              }
          }
        if (list == NULL)
          break;

        if (current_function_decl == 0)
          ctx = comp_unit_die ();
        else
          ctx = lookup_decl_die (current_function_decl);

        decl_die = new_die (DW_TAG_variable, ctx, bound);
        add_AT_flag (decl_die, DW_AT_artificial, 1);
        add_type_attribute (decl_die, TREE_TYPE (bound), 1, 0, ctx);
        add_AT_location_description (decl_die, DW_AT_location, list);
        add_AT_die_ref (subrange_die, bound_attr, decl_die);
        break;
      }
    }
}

/* Add subscript info to TYPE_DIE, describing an array TYPE, collapsing
   possibly nested array subscripts in a flat sequence if COLLAPSE_P is true.
   Note that the block of subscript information for an array type also
   includes information about the element type of the given array type.  */

static void
add_subscript_info (dw_die_ref type_die, tree type, bool collapse_p)
{
  unsigned dimension_number;
  tree lower, upper;
  dw_die_ref subrange_die;

  for (dimension_number = 0;
       TREE_CODE (type) == ARRAY_TYPE && (dimension_number == 0 || collapse_p);
       type = TREE_TYPE (type), dimension_number++)
    {
      tree domain = TYPE_DOMAIN (type);

      if (TYPE_STRING_FLAG (type) && is_fortran () && dimension_number > 0)
        break;

      /* Arrays come in three flavors: Unspecified bounds, fixed bounds,
         and (in GNU C only) variable bounds.  Handle all three forms
         here.  */
      subrange_die = new_die (DW_TAG_subrange_type, type_die, NULL);
      if (domain)
        {
          /* We have an array type with specified bounds.  */
          lower = TYPE_MIN_VALUE (domain);
          upper = TYPE_MAX_VALUE (domain);

          /* Define the index type.  */
          if (TREE_TYPE (domain))
            {
              /* ??? This is probably an Ada unnamed subrange type.  Ignore the
                 TREE_TYPE field.  We can't emit debug info for this
                 because it is an unnamed integral type.  */
              if (TREE_CODE (domain) == INTEGER_TYPE
                  && TYPE_NAME (domain) == NULL_TREE
                  && TREE_CODE (TREE_TYPE (domain)) == INTEGER_TYPE
                  && TYPE_NAME (TREE_TYPE (domain)) == NULL_TREE)
                ;
              else
                add_type_attribute (subrange_die, TREE_TYPE (domain), 0, 0,
                                    type_die);
            }

          /* ??? If upper is NULL, the array has unspecified length,
             but it does have a lower bound.  This happens with Fortran
               dimension arr(N:*)
             Since the debugger is definitely going to need to know N
             to produce useful results, go ahead and output the lower
             bound solo, and hope the debugger can cope.  */

          add_bound_info (subrange_die, DW_AT_lower_bound, lower);
          if (upper)
            add_bound_info (subrange_die, DW_AT_upper_bound, upper);
        }

      /* Otherwise we have an array type with an unspecified length.  The
         DWARF-2 spec does not say how to handle this; let's just leave out the
         bounds.  */
    }
}

static void
add_byte_size_attribute (dw_die_ref die, tree tree_node)
{
  unsigned size;

  switch (TREE_CODE (tree_node))
    {
    case ERROR_MARK:
      size = 0;
      break;
    case ENUMERAL_TYPE:
    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      size = int_size_in_bytes (tree_node);
      break;
    case FIELD_DECL:
      /* For a data member of a struct or union, the DW_AT_byte_size is
         generally given as the number of bytes normally allocated for an
         object of the *declared* type of the member itself.  This is true
         even for bit-fields.  */
      size = simple_type_size_in_bits (field_type (tree_node)) / BITS_PER_UNIT;
      break;
    default:
      gcc_unreachable ();
    }

  /* Note that `size' might be -1 when we get to this point.  If it is, that
     indicates that the byte size of the entity in question is variable.  We
     have no good way of expressing this fact in Dwarf at the present time,
     so just let the -1 pass on through.  */
  add_AT_unsigned (die, DW_AT_byte_size, size);
}

/* For a FIELD_DECL node which represents a bit-field, output an attribute
   which specifies the distance in bits from the highest order bit of the
   "containing object" for the bit-field to the highest order bit of the
   bit-field itself.

   For any given bit-field, the "containing object" is a hypothetical object
   (of some integral or enum type) within which the given bit-field lives.  The
   type of this hypothetical "containing object" is always the same as the
   declared type of the individual bit-field itself.  The determination of the
   exact location of the "containing object" for a bit-field is rather
   complicated.  It's handled by the `field_byte_offset' function (above).

   Note that it is the size (in bytes) of the hypothetical "containing object"
   which will be given in the DW_AT_byte_size attribute for this bit-field.
   (See `byte_size_attribute' above).  */

static inline void
add_bit_offset_attribute (dw_die_ref die, tree decl)
{
  HOST_WIDE_INT object_offset_in_bytes = field_byte_offset (decl);
  tree type = DECL_BIT_FIELD_TYPE (decl);
  HOST_WIDE_INT bitpos_int;
  HOST_WIDE_INT highest_order_object_bit_offset;
  HOST_WIDE_INT highest_order_field_bit_offset;
  HOST_WIDE_INT unsigned bit_offset;

  /* Must be a field and a bit field.  */
  gcc_assert (type && TREE_CODE (decl) == FIELD_DECL);

  /* We can't yet handle bit-fields whose offsets are variable, so if we
     encounter such things, just return without generating any attribute
     whatsoever.  Likewise for variable or too large size.  */
  if (! host_integerp (bit_position (decl), 0)
      || ! host_integerp (DECL_SIZE (decl), 1))
    return;

  bitpos_int = int_bit_position (decl);

  /* Note that the bit offset is always the distance (in bits) from the
     highest-order bit of the "containing object" to the highest-order bit of
     the bit-field itself.  Since the "high-order end" of any object or field
     is different on big-endian and little-endian machines, the computation
     below must take account of these differences.  */
  highest_order_object_bit_offset = object_offset_in_bytes * BITS_PER_UNIT;
  highest_order_field_bit_offset = bitpos_int;

  if (! BYTES_BIG_ENDIAN)
    {
      highest_order_field_bit_offset += tree_low_cst (DECL_SIZE (decl), 0);
      highest_order_object_bit_offset += simple_type_size_in_bits (type);
    }

  bit_offset
    = (! BYTES_BIG_ENDIAN
       ? highest_order_object_bit_offset - highest_order_field_bit_offset
       : highest_order_field_bit_offset - highest_order_object_bit_offset);

  add_AT_unsigned (die, DW_AT_bit_offset, bit_offset);
}

/* For a FIELD_DECL node which represents a bit field, output an attribute
   which specifies the length in bits of the given field.  */

static inline void
add_bit_size_attribute (dw_die_ref die, tree decl)
{
  /* Must be a field and a bit field.  */
  gcc_assert (TREE_CODE (decl) == FIELD_DECL
              && DECL_BIT_FIELD_TYPE (decl));

  if (host_integerp (DECL_SIZE (decl), 1))
    add_AT_unsigned (die, DW_AT_bit_size, tree_low_cst (DECL_SIZE (decl), 1));
}

/* If the compiled language is ANSI C, then add a 'prototyped'
   attribute, if arg types are given for the parameters of a function.  */

static inline void
add_prototyped_attribute (dw_die_ref die, tree func_type)
{
  if (get_AT_unsigned (comp_unit_die (), DW_AT_language) == DW_LANG_C89
      && prototype_p (func_type))
    add_AT_flag (die, DW_AT_prototyped, 1);
}

/* Add an 'abstract_origin' attribute below a given DIE.  The DIE is found
   by looking in either the type declaration or object declaration
   equate table.  */

static inline dw_die_ref
add_abstract_origin_attribute (dw_die_ref die, tree origin)
{
  dw_die_ref origin_die = NULL;

  if (TREE_CODE (origin) != FUNCTION_DECL)
    {
      /* We may have gotten separated from the block for the inlined
         function, if we're in an exception handler or some such; make
         sure that the abstract function has been written out.

         Doing this for nested functions is wrong, however; functions are
         distinct units, and our context might not even be inline.  */
      tree fn = origin;

      if (TYPE_P (fn))
        fn = TYPE_STUB_DECL (fn);

      fn = decl_function_context (fn);
      if (fn)
        dwarf2out_abstract_function (fn);
    }

  if (DECL_P (origin))
    origin_die = lookup_decl_die (origin);
  else if (TYPE_P (origin))
    origin_die = lookup_type_die (origin);

  /* XXX: Functions that are never lowered don't always have correct block
     trees (in the case of java, they simply have no block tree, in some other
     languages).  For these functions, there is nothing we can really do to
     output correct debug info for inlined functions in all cases.  Rather
     than die, we'll just produce deficient debug info now, in that we will
     have variables without a proper abstract origin.  In the future, when all
     functions are lowered, we should re-add a gcc_assert (origin_die)
     here.  */

  if (origin_die)
    add_AT_die_ref (die, DW_AT_abstract_origin, origin_die);
  return origin_die;
}

/* We do not currently support the pure_virtual attribute.  */

static inline void
add_pure_or_virtual_attribute (dw_die_ref die, tree func_decl)
{
  if (DECL_VINDEX (func_decl))
    {
      add_AT_unsigned (die, DW_AT_virtuality, DW_VIRTUALITY_virtual);

      if (host_integerp (DECL_VINDEX (func_decl), 0))
        add_AT_loc (die, DW_AT_vtable_elem_location,
                    new_loc_descr (DW_OP_constu,
                                   tree_low_cst (DECL_VINDEX (func_decl), 0),
                                   0));

      /* GNU extension: Record what type this method came from originally.  */
      if (debug_info_level > DINFO_LEVEL_TERSE
          && DECL_CONTEXT (func_decl))
        add_AT_die_ref (die, DW_AT_containing_type,
                        lookup_type_die (DECL_CONTEXT (func_decl)));
    }
}
\f
/* Add a DW_AT_linkage_name or DW_AT_MIPS_linkage_name attribute for the
   given decl.  This used to be a vendor extension until after DWARF 4
   standardized it.  */

static void
add_linkage_attr (dw_die_ref die, tree decl)
{
  const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));

  /* Mimic what assemble_name_raw does with a leading '*'.  */
  if (name[0] == '*')
    name = &name[1];

  if (dwarf_version >= 4)
    add_AT_string (die, DW_AT_linkage_name, name);
  else
    add_AT_string (die, DW_AT_MIPS_linkage_name, name);
}

/* Add source coordinate attributes for the given decl.  */

static void
add_src_coords_attributes (dw_die_ref die, tree decl)
{
  expanded_location s = expand_location (DECL_SOURCE_LOCATION (decl));

  add_AT_file (die, DW_AT_decl_file, lookup_filename (s.file));
  add_AT_unsigned (die, DW_AT_decl_line, s.line);
}

/* Add DW_AT_{,MIPS_}linkage_name attribute for the given decl.  */

static void
add_linkage_name (dw_die_ref die, tree decl)
{
  if ((TREE_CODE (decl) == FUNCTION_DECL || TREE_CODE (decl) == VAR_DECL)
       && TREE_PUBLIC (decl)
       && !DECL_ABSTRACT (decl)
       && !(TREE_CODE (decl) == VAR_DECL && DECL_REGISTER (decl))
       && die->die_tag != DW_TAG_member)
    {
      /* Defer until we have an assembler name set.  */
      if (!DECL_ASSEMBLER_NAME_SET_P (decl))
        {
          limbo_die_node *asm_name;

          asm_name = ggc_alloc_cleared_limbo_die_node ();
          asm_name->die = die;
          asm_name->created_for = decl;
          asm_name->next = deferred_asm_name;
          deferred_asm_name = asm_name;
        }
      else if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl))
        add_linkage_attr (die, decl);
    }
}

/* Add a DW_AT_name attribute and source coordinate attribute for the
   given decl, but only if it actually has a name.  */

static void
add_name_and_src_coords_attributes (dw_die_ref die, tree decl)
{
  tree decl_name;

  decl_name = DECL_NAME (decl);
  if (decl_name != NULL && IDENTIFIER_POINTER (decl_name) != NULL)
    {
      const char *name = dwarf2_name (decl, 0);
      if (name)
        add_name_attribute (die, name);
      if (! DECL_ARTIFICIAL (decl))
        add_src_coords_attributes (die, decl);

      add_linkage_name (die, decl);
    }

#ifdef VMS_DEBUGGING_INFO
  /* Get the function's name, as described by its RTL.  This may be different
     from the DECL_NAME name used in the source file.  */
  if (TREE_CODE (decl) == FUNCTION_DECL && TREE_ASM_WRITTEN (decl))
    {
      add_AT_addr (die, DW_AT_VMS_rtnbeg_pd_address,
                   XEXP (DECL_RTL (decl), 0));
      VEC_safe_push (rtx, gc, used_rtx_array, XEXP (DECL_RTL (decl), 0));
    }
#endif /* VMS_DEBUGGING_INFO */
}

#ifdef VMS_DEBUGGING_INFO
/* Output the debug main pointer die for VMS */

void
dwarf2out_vms_debug_main_pointer (void)
{
  char label[MAX_ARTIFICIAL_LABEL_BYTES];
  dw_die_ref die;

  /* Allocate the VMS debug main subprogram die.  */
  die = ggc_alloc_cleared_die_node ();
  die->die_tag = DW_TAG_subprogram;
  add_name_attribute (die, VMS_DEBUG_MAIN_POINTER);
  ASM_GENERATE_INTERNAL_LABEL (label, PROLOGUE_END_LABEL,
                               current_function_funcdef_no);
  add_AT_lbl_id (die, DW_AT_entry_pc, label);

  /* Make it the first child of comp_unit_die ().  */
  die->die_parent = comp_unit_die ();
  if (comp_unit_die ()->die_child)
    {
      die->die_sib = comp_unit_die ()->die_child->die_sib;
      comp_unit_die ()->die_child->die_sib = die;
    }
  else
    {
      die->die_sib = die;
      comp_unit_die ()->die_child = die;
    }
}
#endif /* VMS_DEBUGGING_INFO */

/* Push a new declaration scope.  */

static void
push_decl_scope (tree scope)
{
  VEC_safe_push (tree, gc, decl_scope_table, scope);
}

/* Pop a declaration scope.  */

static inline void
pop_decl_scope (void)
{
  VEC_pop (tree, decl_scope_table);
}

/* Return the DIE for the scope that immediately contains this type.
   Non-named types get global scope.  Named types nested in other
   types get their containing scope if it's open, or global scope
   otherwise.  All other types (i.e. function-local named types) get
   the current active scope.  */

static dw_die_ref
scope_die_for (tree t, dw_die_ref context_die)
{
  dw_die_ref scope_die = NULL;
  tree containing_scope;
  int i;

  /* Non-types always go in the current scope.  */
  gcc_assert (TYPE_P (t));

  containing_scope = TYPE_CONTEXT (t);

  /* Use the containing namespace if it was passed in (for a declaration).  */
  if (containing_scope && TREE_CODE (containing_scope) == NAMESPACE_DECL)
    {
      if (context_die == lookup_decl_die (containing_scope))
        /* OK */;
      else
        containing_scope = NULL_TREE;
    }

  /* Ignore function type "scopes" from the C frontend.  They mean that
     a tagged type is local to a parmlist of a function declarator, but
     that isn't useful to DWARF.  */
  if (containing_scope && TREE_CODE (containing_scope) == FUNCTION_TYPE)
    containing_scope = NULL_TREE;

  if (SCOPE_FILE_SCOPE_P (containing_scope))
    scope_die = comp_unit_die ();
  else if (TYPE_P (containing_scope))
    {
      /* For types, we can just look up the appropriate DIE.  But
         first we check to see if we're in the middle of emitting it
         so we know where the new DIE should go.  */
      for (i = VEC_length (tree, decl_scope_table) - 1; i >= 0; --i)
        if (VEC_index (tree, decl_scope_table, i) == containing_scope)
          break;

      if (i < 0)
        {
          gcc_assert (debug_info_level <= DINFO_LEVEL_TERSE
                      || TREE_ASM_WRITTEN (containing_scope));
          /*We are not in the middle of emitting the type
            CONTAINING_SCOPE. Let's see if it's emitted already.  */
          scope_die = lookup_type_die (containing_scope);

          /* If none of the current dies are suitable, we get file scope.  */
          if (scope_die == NULL)
            scope_die = comp_unit_die ();
        }
      else
        scope_die = lookup_type_die_strip_naming_typedef (containing_scope);
    }
  else
    scope_die = context_die;

  return scope_die;
}

/* Returns nonzero if CONTEXT_DIE is internal to a function.  */

static inline int
local_scope_p (dw_die_ref context_die)
{
  for (; context_die; context_die = context_die->die_parent)
    if (context_die->die_tag == DW_TAG_inlined_subroutine
        || context_die->die_tag == DW_TAG_subprogram)
      return 1;

  return 0;
}

/* Returns nonzero if CONTEXT_DIE is a class.  */

static inline int
class_scope_p (dw_die_ref context_die)
{
  return (context_die
          && (context_die->die_tag == DW_TAG_structure_type
              || context_die->die_tag == DW_TAG_class_type
              || context_die->die_tag == DW_TAG_interface_type
              || context_die->die_tag == DW_TAG_union_type));
}

/* Returns nonzero if CONTEXT_DIE is a class or namespace, for deciding
   whether or not to treat a DIE in this context as a declaration.  */

static inline int
class_or_namespace_scope_p (dw_die_ref context_die)
{
  return (class_scope_p (context_die)
          || (context_die && context_die->die_tag == DW_TAG_namespace));
}

/* Many forms of DIEs require a "type description" attribute.  This
   routine locates the proper "type descriptor" die for the type given
   by 'type', and adds a DW_AT_type attribute below the given die.  */

static void
add_type_attribute (dw_die_ref object_die, tree type, int decl_const,
                    int decl_volatile, dw_die_ref context_die)
{
  enum tree_code code  = TREE_CODE (type);
  dw_die_ref type_die  = NULL;

  /* ??? If this type is an unnamed subrange type of an integral, floating-point
     or fixed-point type, use the inner type.  This is because we have no
     support for unnamed types in base_type_die.  This can happen if this is
     an Ada subrange type.  Correct solution is emit a subrange type die.  */
  if ((code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE)
      && TREE_TYPE (type) != 0 && TYPE_NAME (type) == 0)
    type = TREE_TYPE (type), code = TREE_CODE (type);

  if (code == ERROR_MARK
      /* Handle a special case.  For functions whose return type is void, we
         generate *no* type attribute.  (Note that no object may have type
         `void', so this only applies to function return types).  */
      || code == VOID_TYPE)
    return;

  type_die = modified_type_die (type,
                                decl_const || TYPE_READONLY (type),
                                decl_volatile || TYPE_VOLATILE (type),
                                context_die);

  if (type_die != NULL)
    add_AT_die_ref (object_die, DW_AT_type, type_die);
}

/* Given an object die, add the calling convention attribute for the
   function call type.  */
static void
add_calling_convention_attribute (dw_die_ref subr_die, tree decl)
{
  enum dwarf_calling_convention value = DW_CC_normal;

  value = ((enum dwarf_calling_convention)
           targetm.dwarf_calling_convention (TREE_TYPE (decl)));

  if (is_fortran ()
      && !strcmp (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)), "MAIN__"))
    {
      /* DWARF 2 doesn't provide a way to identify a program's source-level
        entry point.  DW_AT_calling_convention attributes are only meant
        to describe functions' calling conventions.  However, lacking a
        better way to signal the Fortran main program, we used this for 
        a long time, following existing custom.  Now, DWARF 4 has 
        DW_AT_main_subprogram, which we add below, but some tools still
        rely on the old way, which we thus keep.  */
      value = DW_CC_program;

      if (dwarf_version >= 4 || !dwarf_strict)
        add_AT_flag (subr_die, DW_AT_main_subprogram, 1);
    }

  /* Only add the attribute if the backend requests it, and
     is not DW_CC_normal.  */
  if (value && (value != DW_CC_normal))
    add_AT_unsigned (subr_die, DW_AT_calling_convention, value);
}

/* Given a tree pointer to a struct, class, union, or enum type node, return
   a pointer to the (string) tag name for the given type, or zero if the type
   was declared without a tag.  */

static const char *
type_tag (const_tree type)
{
  const char *name = 0;

  if (TYPE_NAME (type) != 0)
    {
      tree t = 0;

      /* Find the IDENTIFIER_NODE for the type name.  */
      if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE
          && !TYPE_NAMELESS (type))
        t = TYPE_NAME (type);

      /* The g++ front end makes the TYPE_NAME of *each* tagged type point to
         a TYPE_DECL node, regardless of whether or not a `typedef' was
         involved.  */
      else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
               && ! DECL_IGNORED_P (TYPE_NAME (type)))
        {
          /* We want to be extra verbose.  Don't call dwarf_name if
             DECL_NAME isn't set.  The default hook for decl_printable_name
             doesn't like that, and in this context it's correct to return
             0, instead of "<anonymous>" or the like.  */
          if (DECL_NAME (TYPE_NAME (type))
              && !DECL_NAMELESS (TYPE_NAME (type)))
            name = lang_hooks.dwarf_name (TYPE_NAME (type), 2);
        }

      /* Now get the name as a string, or invent one.  */
      if (!name && t != 0)
        name = IDENTIFIER_POINTER (t);
    }

  return (name == 0 || *name == '\0') ? 0 : name;
}

/* Return the type associated with a data member, make a special check
   for bit field types.  */

static inline tree
member_declared_type (const_tree member)
{
  return (DECL_BIT_FIELD_TYPE (member)
          ? DECL_BIT_FIELD_TYPE (member) : TREE_TYPE (member));
}

/* Get the decl's label, as described by its RTL. This may be different
   from the DECL_NAME name used in the source file.  */

#if 0
static const char *
decl_start_label (tree decl)
{
  rtx x;
  const char *fnname;

  x = DECL_RTL (decl);
  gcc_assert (MEM_P (x));

  x = XEXP (x, 0);
  gcc_assert (GET_CODE (x) == SYMBOL_REF);

  fnname = XSTR (x, 0);
  return fnname;
}
#endif
\f
/* These routines generate the internal representation of the DIE's for
   the compilation unit.  Debugging information is collected by walking
   the declaration trees passed in from dwarf2out_decl().  */

static void
gen_array_type_die (tree type, dw_die_ref context_die)
{
  dw_die_ref scope_die = scope_die_for (type, context_die);
  dw_die_ref array_die;

  /* GNU compilers represent multidimensional array types as sequences of one
     dimensional array types whose element types are themselves array types.
     We sometimes squish that down to a single array_type DIE with multiple
     subscripts in the Dwarf debugging info.  The draft Dwarf specification
     say that we are allowed to do this kind of compression in C, because
     there is no difference between an array of arrays and a multidimensional
     array.  We don't do this for Ada to remain as close as possible to the
     actual representation, which is especially important against the language
     flexibilty wrt arrays of variable size.  */

  bool collapse_nested_arrays = !is_ada ();
  tree element_type;

  /* Emit DW_TAG_string_type for Fortran character types (with kind 1 only, as
     DW_TAG_string_type doesn't have DW_AT_type attribute).  */
  if (TYPE_STRING_FLAG (type)
      && TREE_CODE (type) == ARRAY_TYPE
      && is_fortran ()
      && TYPE_MODE (TREE_TYPE (type)) == TYPE_MODE (char_type_node))
    {
      HOST_WIDE_INT size;

      array_die = new_die (DW_TAG_string_type, scope_die, type);
      add_name_attribute (array_die, type_tag (type));
      equate_type_number_to_die (type, array_die);
      size = int_size_in_bytes (type);
      if (size >= 0)
        add_AT_unsigned (array_die, DW_AT_byte_size, size);
      else if (TYPE_DOMAIN (type) != NULL_TREE
               && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) != NULL_TREE
               && DECL_P (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
        {
          tree szdecl = TYPE_MAX_VALUE (TYPE_DOMAIN (type));
          dw_loc_list_ref loc = loc_list_from_tree (szdecl, 2);

          size = int_size_in_bytes (TREE_TYPE (szdecl));
          if (loc && size > 0)
            {
              add_AT_location_description (array_die, DW_AT_string_length, loc);
              if (size != DWARF2_ADDR_SIZE)
                add_AT_unsigned (array_die, DW_AT_byte_size, size);
            }
        }
      return;
    }

  /* ??? The SGI dwarf reader fails for array of array of enum types
     (e.g. const enum machine_mode insn_operand_mode[2][10]) unless the inner
     array type comes before the outer array type.  We thus call gen_type_die
     before we new_die and must prevent nested array types collapsing for this
     target.  */

#ifdef MIPS_DEBUGGING_INFO
  gen_type_die (TREE_TYPE (type), context_die);
  collapse_nested_arrays = false;
#endif

  array_die = new_die (DW_TAG_array_type, scope_die, type);
  add_name_attribute (array_die, type_tag (type));
  equate_type_number_to_die (type, array_die);

  if (TREE_CODE (type) == VECTOR_TYPE)
    add_AT_flag (array_die, DW_AT_GNU_vector, 1);

  /* For Fortran multidimensional arrays use DW_ORD_col_major ordering.  */
  if (is_fortran ()
      && TREE_CODE (type) == ARRAY_TYPE
      && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE
      && !TYPE_STRING_FLAG (TREE_TYPE (type)))
    add_AT_unsigned (array_die, DW_AT_ordering, DW_ORD_col_major);

#if 0
  /* We default the array ordering.  SDB will probably do
     the right things even if DW_AT_ordering is not present.  It's not even
     an issue until we start to get into multidimensional arrays anyway.  If
     SDB is ever caught doing the Wrong Thing for multi-dimensional arrays,
     then we'll have to put the DW_AT_ordering attribute back in.  (But if
     and when we find out that we need to put these in, we will only do so
     for multidimensional arrays.  */
  add_AT_unsigned (array_die, DW_AT_ordering, DW_ORD_row_major);
#endif

#ifdef MIPS_DEBUGGING_INFO
  /* The SGI compilers handle arrays of unknown bound by setting
     AT_declaration and not emitting any subrange DIEs.  */
  if (TREE_CODE (type) == ARRAY_TYPE
      && ! TYPE_DOMAIN (type))
    add_AT_flag (array_die, DW_AT_declaration, 1);
  else
#endif
  if (TREE_CODE (type) == VECTOR_TYPE)
    {
      /* For VECTOR_TYPEs we use an array die with appropriate bounds.  */
      dw_die_ref subrange_die = new_die (DW_TAG_subrange_type, array_die, NULL);
      add_bound_info (subrange_die, DW_AT_lower_bound, size_zero_node);
      add_bound_info (subrange_die, DW_AT_upper_bound,
                      size_int (TYPE_VECTOR_SUBPARTS (type) - 1));
    }
  else
    add_subscript_info (array_die, type, collapse_nested_arrays);

  /* Add representation of the type of the elements of this array type and
     emit the corresponding DIE if we haven't done it already.  */
  element_type = TREE_TYPE (type);
  if (collapse_nested_arrays)
    while (TREE_CODE (element_type) == ARRAY_TYPE)
      {
        if (TYPE_STRING_FLAG (element_type) && is_fortran ())
          break;
        element_type = TREE_TYPE (element_type);
      }

#ifndef MIPS_DEBUGGING_INFO
  gen_type_die (element_type, context_die);
#endif

  add_type_attribute (array_die, element_type, 0, 0, context_die);

  if (get_AT (array_die, DW_AT_name))
    add_pubtype (type, array_die);
}

static dw_loc_descr_ref
descr_info_loc (tree val, tree base_decl)
{
  HOST_WIDE_INT size;
  dw_loc_descr_ref loc, loc2;
  enum dwarf_location_atom op;

  if (val == base_decl)
    return new_loc_descr (DW_OP_push_object_address, 0, 0);

  switch (TREE_CODE (val))
    {
    CASE_CONVERT:
      return descr_info_loc (TREE_OPERAND (val, 0), base_decl);
    case VAR_DECL:
      return loc_descriptor_from_tree (val, 0);
    case INTEGER_CST:
      if (host_integerp (val, 0))
        return int_loc_descriptor (tree_low_cst (val, 0));
      break;
    case INDIRECT_REF:
      size = int_size_in_bytes (TREE_TYPE (val));
      if (size < 0)
        break;
      loc = descr_info_loc (TREE_OPERAND (val, 0), base_decl);
      if (!loc)
        break;
      if (size == DWARF2_ADDR_SIZE)
        add_loc_descr (&loc, new_loc_descr (DW_OP_deref, 0, 0));
      else
        add_loc_descr (&loc, new_loc_descr (DW_OP_deref_size, size, 0));
      return loc;
    case POINTER_PLUS_EXPR:
    case PLUS_EXPR:
      if (host_integerp (TREE_OPERAND (val, 1), 1)
          && (unsigned HOST_WIDE_INT) tree_low_cst (TREE_OPERAND (val, 1), 1)
             < 16384)
        {
          loc = descr_info_loc (TREE_OPERAND (val, 0), base_decl);
          if (!loc)
            break;
          loc_descr_plus_const (&loc, tree_low_cst (TREE_OPERAND (val, 1), 0));
        }
      else
        {
          op = DW_OP_plus;
        do_binop:
          loc = descr_info_loc (TREE_OPERAND (val, 0), base_decl);
          if (!loc)
            break;
          loc2 = descr_info_loc (TREE_OPERAND (val, 1), base_decl);
          if (!loc2)
            break;
          add_loc_descr (&loc, loc2);
          add_loc_descr (&loc2, new_loc_descr (op, 0, 0));
        }
      return loc;
    case MINUS_EXPR:
      op = DW_OP_minus;
      goto do_binop;
    case MULT_EXPR:
      op = DW_OP_mul;
      goto do_binop;
    case EQ_EXPR:
      op = DW_OP_eq;
      goto do_binop;
    case NE_EXPR:
      op = DW_OP_ne;
      goto do_binop;
    default:
      break;
    }
  return NULL;
}

static void
add_descr_info_field (dw_die_ref die, enum dwarf_attribute attr,
                      tree val, tree base_decl)
{
  dw_loc_descr_ref loc;

  if (host_integerp (val, 0))
    {
      add_AT_unsigned (die, attr, tree_low_cst (val, 0));
      return;
    }

  loc = descr_info_loc (val, base_decl);
  if (!loc)
    return;

  add_AT_loc (die, attr, loc);
}

/* This routine generates DIE for array with hidden descriptor, details
   are filled into *info by a langhook.  */

static void
gen_descr_array_type_die (tree type, struct array_descr_info *info,
                          dw_die_ref context_die)
{
  dw_die_ref scope_die = scope_die_for (type, context_die);
  dw_die_ref array_die;
  int dim;

  array_die = new_die (DW_TAG_array_type, scope_die, type);
  add_name_attribute (array_die, type_tag (type));
  equate_type_number_to_die (type, array_die);

  /* For Fortran multidimensional arrays use DW_ORD_col_major ordering.  */
  if (is_fortran ()
      && info->ndimensions >= 2)
    add_AT_unsigned (array_die, DW_AT_ordering, DW_ORD_col_major);

  if (info->data_location)
    add_descr_info_field (array_die, DW_AT_data_location, info->data_location,
                          info->base_decl);
  if (info->associated)
    add_descr_info_field (array_die, DW_AT_associated, info->associated,
                          info->base_decl);
  if (info->allocated)
    add_descr_info_field (array_die, DW_AT_allocated, info->allocated,
                          info->base_decl);

  for (dim = 0; dim < info->ndimensions; dim++)
    {
      dw_die_ref subrange_die
        = new_die (DW_TAG_subrange_type, array_die, NULL);

      if (info->dimen[dim].lower_bound)
        {
          /* If it is the default value, omit it.  */
          int dflt;

          if (host_integerp (info->dimen[dim].lower_bound, 0)
              && (dflt = lower_bound_default ()) != -1
              && tree_low_cst (info->dimen[dim].lower_bound, 0) == dflt)
            ;
          else
            add_descr_info_field (subrange_die, DW_AT_lower_bound,
                                  info->dimen[dim].lower_bound,
                                  info->base_decl);
        }
      if (info->dimen[dim].upper_bound)
        add_descr_info_field (subrange_die, DW_AT_upper_bound,
                              info->dimen[dim].upper_bound,
                              info->base_decl);
      if (info->dimen[dim].stride)
        add_descr_info_field (subrange_die, DW_AT_byte_stride,
                              info->dimen[dim].stride,
                              info->base_decl);
    }

  gen_type_die (info->element_type, context_die);
  add_type_attribute (array_die, info->element_type, 0, 0, context_die);

  if (get_AT (array_die, DW_AT_name))
    add_pubtype (type, array_die);
}

#if 0
static void
gen_entry_point_die (tree decl, dw_die_ref context_die)
{
  tree origin = decl_ultimate_origin (decl);
  dw_die_ref decl_die = new_die (DW_TAG_entry_point, context_die, decl);

  if (origin != NULL)
    add_abstract_origin_attribute (decl_die, origin);
  else
    {
      add_name_and_src_coords_attributes (decl_die, decl);
      add_type_attribute (decl_die, TREE_TYPE (TREE_TYPE (decl)),
                          0, 0, context_die);
    }

  if (DECL_ABSTRACT (decl))
    equate_decl_number_to_die (decl, decl_die);
  else
    add_AT_lbl_id (decl_die, DW_AT_low_pc, decl_start_label (decl));
}
#endif

/* Walk through the list of incomplete types again, trying once more to
   emit full debugging info for them.  */

static void
retry_incomplete_types (void)
{
  int i;

  for (i = VEC_length (tree, incomplete_types) - 1; i >= 0; i--)
    if (should_emit_struct_debug (VEC_index (tree, incomplete_types, i),
                                  DINFO_USAGE_DIR_USE))
      gen_type_die (VEC_index (tree, incomplete_types, i), comp_unit_die ());
}

/* Determine what tag to use for a record type.  */

static enum dwarf_tag
record_type_tag (tree type)
{
  if (! lang_hooks.types.classify_record)
    return DW_TAG_structure_type;

  switch (lang_hooks.types.classify_record (type))
    {
    case RECORD_IS_STRUCT:
      return DW_TAG_structure_type;

    case RECORD_IS_CLASS:
      return DW_TAG_class_type;

    case RECORD_IS_INTERFACE:
      if (dwarf_version >= 3 || !dwarf_strict)
        return DW_TAG_interface_type;
      return DW_TAG_structure_type;

    default:
      gcc_unreachable ();
    }
}

/* Generate a DIE to represent an enumeration type.  Note that these DIEs
   include all of the information about the enumeration values also. Each
   enumerated type name/value is listed as a child of the enumerated type
   DIE.  */

static dw_die_ref
gen_enumeration_type_die (tree type, dw_die_ref context_die)
{
  dw_die_ref type_die = lookup_type_die (type);

  if (type_die == NULL)
    {
      type_die = new_die (DW_TAG_enumeration_type,
                          scope_die_for (type, context_die), type);
      equate_type_number_to_die (type, type_die);
      add_name_attribute (type_die, type_tag (type));
      if (dwarf_version >= 4 || !dwarf_strict)
        {
          if (ENUM_IS_SCOPED (type))
            add_AT_flag (type_die, DW_AT_enum_class, 1);
          if (ENUM_IS_OPAQUE (type))
            add_AT_flag (type_die, DW_AT_declaration, 1);
        }
    }
  else if (! TYPE_SIZE (type))
    return type_die;
  else
    remove_AT (type_die, DW_AT_declaration);

  /* Handle a GNU C/C++ extension, i.e. incomplete enum types.  If the
     given enum type is incomplete, do not generate the DW_AT_byte_size
     attribute or the DW_AT_element_list attribute.  */
  if (TYPE_SIZE (type))
    {
      tree link;

      TREE_ASM_WRITTEN (type) = 1;
      add_byte_size_attribute (type_die, type);
      if (TYPE_STUB_DECL (type) != NULL_TREE)
        {
          add_src_coords_attributes (type_die, TYPE_STUB_DECL (type));
          add_accessibility_attribute (type_die, TYPE_STUB_DECL (type));
        }

      /* If the first reference to this type was as the return type of an
         inline function, then it may not have a parent.  Fix this now.  */
      if (type_die->die_parent == NULL)
        add_child_die (scope_die_for (type, context_die), type_die);

      for (link = TYPE_VALUES (type);
           link != NULL; link = TREE_CHAIN (link))
        {
          dw_die_ref enum_die = new_die (DW_TAG_enumerator, type_die, link);
          tree value = TREE_VALUE (link);

          add_name_attribute (enum_die,
                              IDENTIFIER_POINTER (TREE_PURPOSE (link)));

          if (TREE_CODE (value) == CONST_DECL)
            value = DECL_INITIAL (value);

          if (host_integerp (value, TYPE_UNSIGNED (TREE_TYPE (value))))
            /* DWARF2 does not provide a way of indicating whether or
               not enumeration constants are signed or unsigned.  GDB
               always assumes the values are signed, so we output all
               values as if they were signed.  That means that
               enumeration constants with very large unsigned values
               will appear to have negative values in the debugger.  */
            add_AT_int (enum_die, DW_AT_const_value,
                        tree_low_cst (value, tree_int_cst_sgn (value) > 0));
        }
    }
  else
    add_AT_flag (type_die, DW_AT_declaration, 1);

  if (get_AT (type_die, DW_AT_name))
    add_pubtype (type, type_die);

  return type_die;
}

/* Generate a DIE to represent either a real live formal parameter decl or to
   represent just the type of some formal parameter position in some function
   type.

   Note that this routine is a bit unusual because its argument may be a
   ..._DECL node (i.e. either a PARM_DECL or perhaps a VAR_DECL which
   represents an inlining of some PARM_DECL) or else some sort of a ..._TYPE
   node.  If it's the former then this function is being called to output a
   DIE to represent a formal parameter object (or some inlining thereof).  If
   it's the latter, then this function is only being called to output a
   DW_TAG_formal_parameter DIE to stand as a placeholder for some formal
   argument type of some subprogram type.
   If EMIT_NAME_P is true, name and source coordinate attributes
   are emitted.  */

static dw_die_ref
gen_formal_parameter_die (tree node, tree origin, bool emit_name_p,
                          dw_die_ref context_die)
{
  tree node_or_origin = node ? node : origin;
  tree ultimate_origin;
  dw_die_ref parm_die
    = new_die (DW_TAG_formal_parameter, context_die, node);

  switch (TREE_CODE_CLASS (TREE_CODE (node_or_origin)))
    {
    case tcc_declaration:
      ultimate_origin = decl_ultimate_origin (node_or_origin);
      if (node || ultimate_origin)
        origin = ultimate_origin;
      if (origin != NULL)
        add_abstract_origin_attribute (parm_die, origin);
      else if (emit_name_p)
        add_name_and_src_coords_attributes (parm_die, node);
      if (origin == NULL
          || (! DECL_ABSTRACT (node_or_origin)
              && variably_modified_type_p (TREE_TYPE (node_or_origin),
                                           decl_function_context
                                                            (node_or_origin))))
        {
          tree type = TREE_TYPE (node_or_origin);
          if (decl_by_reference_p (node_or_origin))
            add_type_attribute (parm_die, TREE_TYPE (type), 0, 0,
                                context_die);
          else
            add_type_attribute (parm_die, type,
                                TREE_READONLY (node_or_origin),
                                TREE_THIS_VOLATILE (node_or_origin),
                                context_die);
        }
      if (origin == NULL && DECL_ARTIFICIAL (node))
        add_AT_flag (parm_die, DW_AT_artificial, 1);

      if (node && node != origin)
        equate_decl_number_to_die (node, parm_die);
      if (! DECL_ABSTRACT (node_or_origin))
        add_location_or_const_value_attribute (parm_die, node_or_origin,
                                               DW_AT_location);

      break;

    case tcc_type:
      /* We were called with some kind of a ..._TYPE node.  */
      add_type_attribute (parm_die, node_or_origin, 0, 0, context_die);
      break;

    default:
      gcc_unreachable ();
    }

  return parm_die;
}

/* Generate and return a DW_TAG_GNU_formal_parameter_pack. Also generate
   children DW_TAG_formal_parameter DIEs representing the arguments of the
   parameter pack.

   PARM_PACK must be a function parameter pack.
   PACK_ARG is the first argument of the parameter pack. Its TREE_CHAIN
   must point to the subsequent arguments of the function PACK_ARG belongs to.
   SUBR_DIE is the DIE of the function PACK_ARG belongs to.
   If NEXT_ARG is non NULL, *NEXT_ARG is set to the function argument
   following the last one for which a DIE was generated.  */

static dw_die_ref
gen_formal_parameter_pack_die  (tree parm_pack,
                                tree pack_arg,
                                dw_die_ref subr_die,
                                tree *next_arg)
{
  tree arg;
  dw_die_ref parm_pack_die;

  gcc_assert (parm_pack
              && lang_hooks.function_parameter_pack_p (parm_pack)
              && subr_die);

  parm_pack_die = new_die (DW_TAG_GNU_formal_parameter_pack, subr_die, parm_pack);
  add_src_coords_attributes (parm_pack_die, parm_pack);

  for (arg = pack_arg; arg; arg = DECL_CHAIN (arg))
    {
      if (! lang_hooks.decls.function_parm_expanded_from_pack_p (arg,
                                                                 parm_pack))
        break;
      gen_formal_parameter_die (arg, NULL,
                                false /* Don't emit name attribute.  */,
                                parm_pack_die);
    }
  if (next_arg)
    *next_arg = arg;
  return parm_pack_die;
}

/* Generate a special type of DIE used as a stand-in for a trailing ellipsis
   at the end of an (ANSI prototyped) formal parameters list.  */

static void
gen_unspecified_parameters_die (tree decl_or_type, dw_die_ref context_die)
{
  new_die (DW_TAG_unspecified_parameters, context_die, decl_or_type);
}

/* Generate a list of nameless DW_TAG_formal_parameter DIEs (and perhaps a
   DW_TAG_unspecified_parameters DIE) to represent the types of the formal
   parameters as specified in some function type specification (except for
   those which appear as part of a function *definition*).  */

static void
gen_formal_types_die (tree function_or_method_type, dw_die_ref context_die)
{
  tree link;
  tree formal_type = NULL;
  tree first_parm_type;
  tree arg;

  if (TREE_CODE (function_or_method_type) == FUNCTION_DECL)
    {
      arg = DECL_ARGUMENTS (function_or_method_type);
      function_or_method_type = TREE_TYPE (function_or_method_type);
    }
  else
    arg = NULL_TREE;

  first_parm_type = TYPE_ARG_TYPES (function_or_method_type);

  /* Make our first pass over the list of formal parameter types and output a
     DW_TAG_formal_parameter DIE for each one.  */
  for (link = first_parm_type; link; )
    {
      dw_die_ref parm_die;

      formal_type = TREE_VALUE (link);
      if (formal_type == void_type_node)
        break;

      /* Output a (nameless) DIE to represent the formal parameter itself.  */
      parm_die = gen_formal_parameter_die (formal_type, NULL,
                                           true /* Emit name attribute.  */,
                                           context_die);
      if (TREE_CODE (function_or_method_type) == METHOD_TYPE
          && link == first_parm_type)
        {
          add_AT_flag (parm_die, DW_AT_artificial, 1);
          if (dwarf_version >= 3 || !dwarf_strict)
            add_AT_die_ref (context_die, DW_AT_object_pointer, parm_die);
        }
      else if (arg && DECL_ARTIFICIAL (arg))
        add_AT_flag (parm_die, DW_AT_artificial, 1);

      link = TREE_CHAIN (link);
      if (arg)
        arg = DECL_CHAIN (arg);
    }

  /* If this function type has an ellipsis, add a
     DW_TAG_unspecified_parameters DIE to the end of the parameter list.  */
  if (formal_type != void_type_node)
    gen_unspecified_parameters_die (function_or_method_type, context_die);

  /* Make our second (and final) pass over the list of formal parameter types
     and output DIEs to represent those types (as necessary).  */
  for (link = TYPE_ARG_TYPES (function_or_method_type);
       link && TREE_VALUE (link);
       link = TREE_CHAIN (link))
    gen_type_die (TREE_VALUE (link), context_die);
}

/* We want to generate the DIE for TYPE so that we can generate the
   die for MEMBER, which has been defined; we will need to refer back
   to the member declaration nested within TYPE.  If we're trying to
   generate minimal debug info for TYPE, processing TYPE won't do the
   trick; we need to attach the member declaration by hand.  */

static void
gen_type_die_for_member (tree type, tree member, dw_die_ref context_die)
{
  gen_type_die (type, context_die);

  /* If we're trying to avoid duplicate debug info, we may not have
     emitted the member decl for this function.  Emit it now.  */
  if (TYPE_STUB_DECL (type)
      && TYPE_DECL_SUPPRESS_DEBUG (TYPE_STUB_DECL (type))
      && ! lookup_decl_die (member))
    {
      dw_die_ref type_die;
      gcc_assert (!decl_ultimate_origin (member));

      push_decl_scope (type);
      type_die = lookup_type_die_strip_naming_typedef (type);
      if (TREE_CODE (member) == FUNCTION_DECL)
        gen_subprogram_die (member, type_die);
      else if (TREE_CODE (member) == FIELD_DECL)
        {
          /* Ignore the nameless fields that are used to skip bits but handle
             C++ anonymous unions and structs.  */
          if (DECL_NAME (member) != NULL_TREE
              || TREE_CODE (TREE_TYPE (member)) == UNION_TYPE
              || TREE_CODE (TREE_TYPE (member)) == RECORD_TYPE)
            {
              gen_type_die (member_declared_type (member), type_die);
              gen_field_die (member, type_die);
            }
        }
      else
        gen_variable_die (member, NULL_TREE, type_die);

      pop_decl_scope ();
    }
}

/* Generate the DWARF2 info for the "abstract" instance of a function which we
   may later generate inlined and/or out-of-line instances of.  */

static void
dwarf2out_abstract_function (tree decl)
{
  dw_die_ref old_die;
  tree save_fn;
  tree context;
  int was_abstract;
  htab_t old_decl_loc_table;

  /* Make sure we have the actual abstract inline, not a clone.  */
  decl = DECL_ORIGIN (decl);

  old_die = lookup_decl_die (decl);
  if (old_die && get_AT (old_die, DW_AT_inline))
    /* We've already generated the abstract instance.  */
    return;

  /* We can be called while recursively when seeing block defining inlined subroutine
     DIE.  Be sure to not clobber the outer location table nor use it or we would
     get locations in abstract instantces.  */
  old_decl_loc_table = decl_loc_table;
  decl_loc_table = NULL;

  /* Be sure we've emitted the in-class declaration DIE (if any) first, so
     we don't get confused by DECL_ABSTRACT.  */
  if (debug_info_level > DINFO_LEVEL_TERSE)
    {
      context = decl_class_context (decl);
      if (context)
        gen_type_die_for_member
          (context, decl, decl_function_context (decl) ? NULL : comp_unit_die ());
    }

  /* Pretend we've just finished compiling this function.  */
  save_fn = current_function_decl;
  current_function_decl = decl;
  push_cfun (DECL_STRUCT_FUNCTION (decl));

  was_abstract = DECL_ABSTRACT (decl);
  set_decl_abstract_flags (decl, 1);
  dwarf2out_decl (decl);
  if (! was_abstract)
    set_decl_abstract_flags (decl, 0);

  current_function_decl = save_fn;
  decl_loc_table = old_decl_loc_table;
  pop_cfun ();
}

/* Helper function of premark_used_types() which gets called through
   htab_traverse.

   Marks the DIE of a given type in *SLOT as perennial, so it never gets
   marked as unused by prune_unused_types.  */

static int
premark_used_types_helper (void **slot, void *data ATTRIBUTE_UNUSED)
{
  tree type;
  dw_die_ref die;

  type = (tree) *slot;
  die = lookup_type_die (type);
  if (die != NULL)
    die->die_perennial_p = 1;
  return 1;
}

/* Helper function of premark_types_used_by_global_vars which gets called
   through htab_traverse.

   Marks the DIE of a given type in *SLOT as perennial, so it never gets
   marked as unused by prune_unused_types. The DIE of the type is marked
   only if the global variable using the type will actually be emitted.  */

static int
premark_types_used_by_global_vars_helper (void **slot,
                                          void *data ATTRIBUTE_UNUSED)
{
  struct types_used_by_vars_entry *entry;
  dw_die_ref die;

  entry = (struct types_used_by_vars_entry *) *slot;
  gcc_assert (entry->type != NULL
              && entry->var_decl != NULL);
  die = lookup_type_die (entry->type);
  if (die)
    {
      /* Ask cgraph if the global variable really is to be emitted.
         If yes, then we'll keep the DIE of ENTRY->TYPE.  */
      struct varpool_node *node = varpool_get_node (entry->var_decl);
      if (node && node->needed)
        {
          die->die_perennial_p = 1;
          /* Keep the parent DIEs as well.  */
          while ((die = die->die_parent) && die->die_perennial_p == 0)
            die->die_perennial_p = 1;
        }
    }
  return 1;
}

/* Mark all members of used_types_hash as perennial.  */

static void
premark_used_types (void)
{
  if (cfun && cfun->used_types_hash)
    htab_traverse (cfun->used_types_hash, premark_used_types_helper, NULL);
}

/* Mark all members of types_used_by_vars_entry as perennial.  */

static void
premark_types_used_by_global_vars (void)
{
  if (types_used_by_vars_hash)
    htab_traverse (types_used_by_vars_hash,
                   premark_types_used_by_global_vars_helper, NULL);
}

/* Generate a DIE to represent a declared function (either file-scope or
   block-local).  */

static void
gen_subprogram_die (tree decl, dw_die_ref context_die)
{
  tree origin = decl_ultimate_origin (decl);
  dw_die_ref subr_die;
  tree outer_scope;
  dw_die_ref old_die = lookup_decl_die (decl);
  int declaration = (current_function_decl != decl
                     || class_or_namespace_scope_p (context_die));

  premark_used_types ();

  /* It is possible to have both DECL_ABSTRACT and DECLARATION be true if we
     started to generate the abstract instance of an inline, decided to output
     its containing class, and proceeded to emit the declaration of the inline
     from the member list for the class.  If so, DECLARATION takes priority;
     we'll get back to the abstract instance when done with the class.  */

  /* The class-scope declaration DIE must be the primary DIE.  */
  if (origin && declaration && class_or_namespace_scope_p (context_die))
    {
      origin = NULL;
      gcc_assert (!old_die);
    }

  /* Now that the C++ front end lazily declares artificial member fns, we
     might need to retrofit the declaration into its class.  */
  if (!declaration && !origin && !old_die
      && DECL_CONTEXT (decl) && TYPE_P (DECL_CONTEXT (decl))
      && !class_or_namespace_scope_p (context_die)
      && debug_info_level > DINFO_LEVEL_TERSE)
    old_die = force_decl_die (decl);

  if (origin != NULL)
    {
      gcc_assert (!declaration || local_scope_p (context_die));

      /* Fixup die_parent for the abstract instance of a nested
         inline function.  */
      if (old_die && old_die->die_parent == NULL)
        add_child_die (context_die, old_die);

      subr_die = new_die (DW_TAG_subprogram, context_die, decl);
      add_abstract_origin_attribute (subr_die, origin);
    }
  else if (old_die)
    {
      expanded_location s = expand_location (DECL_SOURCE_LOCATION (decl));
      struct dwarf_file_data * file_index = lookup_filename (s.file);

      if (!get_AT_flag (old_die, DW_AT_declaration)
          /* We can have a normal definition following an inline one in the
             case of redefinition of GNU C extern inlines.
             It seems reasonable to use AT_specification in this case.  */
          && !get_AT (old_die, DW_AT_inline))
        {
          /* Detect and ignore this case, where we are trying to output
             something we have already output.  */
          return;
        }

      /* If the definition comes from the same place as the declaration,
         maybe use the old DIE.  We always want the DIE for this function
         that has the *_pc attributes to be under comp_unit_die so the
         debugger can find it.  We also need to do this for abstract
         instances of inlines, since the spec requires the out-of-line copy
         to have the same parent.  For local class methods, this doesn't
         apply; we just use the old DIE.  */
      if ((is_cu_die (old_die->die_parent) || context_die == NULL)
          && (DECL_ARTIFICIAL (decl)
              || (get_AT_file (old_die, DW_AT_decl_file) == file_index
                  && (get_AT_unsigned (old_die, DW_AT_decl_line)
                      == (unsigned) s.line))))
        {
          subr_die = old_die;

          /* Clear out the declaration attribute and the formal parameters.
             Do not remove all children, because it is possible that this
             declaration die was forced using force_decl_die(). In such
             cases die that forced declaration die (e.g. TAG_imported_module)
             is one of the children that we do not want to remove.  */
          remove_AT (subr_die, DW_AT_declaration);
          remove_AT (subr_die, DW_AT_object_pointer);
          remove_child_TAG (subr_die, DW_TAG_formal_parameter);
        }
      else
        {
          subr_die = new_die (DW_TAG_subprogram, context_die, decl);
          add_AT_specification (subr_die, old_die);
          if (get_AT_file (old_die, DW_AT_decl_file) != file_index)
            add_AT_file (subr_die, DW_AT_decl_file, file_index);
          if (get_AT_unsigned (old_die, DW_AT_decl_line) != (unsigned) s.line)
            add_AT_unsigned (subr_die, DW_AT_decl_line, s.line);
        }
    }
  else
    {
      subr_die = new_die (DW_TAG_subprogram, context_die, decl);

      if (TREE_PUBLIC (decl))
        add_AT_flag (subr_die, DW_AT_external, 1);

      add_name_and_src_coords_attributes (subr_die, decl);
      if (debug_info_level > DINFO_LEVEL_TERSE)
        {
          add_prototyped_attribute (subr_die, TREE_TYPE (decl));
          add_type_attribute (subr_die, TREE_TYPE (TREE_TYPE (decl)),
                              0, 0, context_die);
        }

      add_pure_or_virtual_attribute (subr_die, decl);
      if (DECL_ARTIFICIAL (decl))
        add_AT_flag (subr_die, DW_AT_artificial, 1);

      add_accessibility_attribute (subr_die, decl);
    }

  if (declaration)
    {
      if (!old_die || !get_AT (old_die, DW_AT_inline))
        {
          add_AT_flag (subr_die, DW_AT_declaration, 1);

          /* If this is an explicit function declaration then generate
             a DW_AT_explicit attribute.  */
          if (lang_hooks.decls.function_decl_explicit_p (decl)
              && (dwarf_version >= 3 || !dwarf_strict))
            add_AT_flag (subr_die, DW_AT_explicit, 1);

          /* The first time we see a member function, it is in the context of
             the class to which it belongs.  We make sure of this by emitting
             the class first.  The next time is the definition, which is
             handled above.  The two may come from the same source text.

             Note that force_decl_die() forces function declaration die. It is
             later reused to represent definition.  */
          equate_decl_number_to_die (decl, subr_die);
        }
    }
  else if (DECL_ABSTRACT (decl))
    {
      if (DECL_DECLARED_INLINE_P (decl))
        {
          if (cgraph_function_possibly_inlined_p (decl))
            add_AT_unsigned (subr_die, DW_AT_inline, DW_INL_declared_inlined);
          else
            add_AT_unsigned (subr_die, DW_AT_inline, DW_INL_declared_not_inlined);
        }
      else
        {
          if (cgraph_function_possibly_inlined_p (decl))
            add_AT_unsigned (subr_die, DW_AT_inline, DW_INL_inlined);
          else
            add_AT_unsigned (subr_die, DW_AT_inline, DW_INL_not_inlined);
        }

      if (DECL_DECLARED_INLINE_P (decl)
          && lookup_attribute ("artificial", DECL_ATTRIBUTES (decl)))
        add_AT_flag (subr_die, DW_AT_artificial, 1);

      equate_decl_number_to_die (decl, subr_die);
    }
  else if (!DECL_EXTERNAL (decl))
    {
      HOST_WIDE_INT cfa_fb_offset;

      if (!old_die || !get_AT (old_die, DW_AT_inline))
        equate_decl_number_to_die (decl, subr_die);

      if (!flag_reorder_blocks_and_partition)
        {
          dw_fde_ref fde = &fde_table[current_funcdef_fde];
          if (fde->dw_fde_begin)
            {
              /* We have already generated the labels.  */
              add_AT_lbl_id (subr_die, DW_AT_low_pc, fde->dw_fde_begin);
              add_AT_lbl_id (subr_die, DW_AT_high_pc, fde->dw_fde_end);
            }
          else
            {
              /* Create start/end labels and add the range.  */
              char label_id[MAX_ARTIFICIAL_LABEL_BYTES];
              ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_BEGIN_LABEL,
                                           current_function_funcdef_no);
              add_AT_lbl_id (subr_die, DW_AT_low_pc, label_id);
              ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_END_LABEL,
                                           current_function_funcdef_no);
              add_AT_lbl_id (subr_die, DW_AT_high_pc, label_id);
            }

#if VMS_DEBUGGING_INFO
      /* HP OpenVMS Industry Standard 64: DWARF Extensions
         Section 2.3 Prologue and Epilogue Attributes:
         When a breakpoint is set on entry to a function, it is generally
         desirable for execution to be suspended, not on the very first
         instruction of the function, but rather at a point after the
         function's frame has been set up, after any language defined local
         declaration processing has been completed, and before execution of
         the first statement of the function begins. Debuggers generally
         cannot properly determine where this point is.  Similarly for a
         breakpoint set on exit from a function. The prologue and epilogue
         attributes allow a compiler to communicate the location(s) to use.  */

      {
        if (fde->dw_fde_vms_end_prologue)
          add_AT_vms_delta (subr_die, DW_AT_HP_prologue,
            fde->dw_fde_begin, fde->dw_fde_vms_end_prologue);

        if (fde->dw_fde_vms_begin_epilogue)
          add_AT_vms_delta (subr_die, DW_AT_HP_epilogue,
            fde->dw_fde_begin, fde->dw_fde_vms_begin_epilogue);
      }
#endif

          add_pubname (decl, subr_die);
          add_arange (decl, subr_die);
        }
      else
        {  /* Generate pubnames entries for the split function code
              ranges.  */
          dw_fde_ref fde = &fde_table[current_funcdef_fde];

          if (fde->dw_fde_switched_sections)
            {
              if (dwarf_version >= 3 || !dwarf_strict)
                {
                  /* We should use ranges for non-contiguous code section 
                     addresses.  Use the actual code range for the initial
                     section, since the HOT/COLD labels might precede an 
                     alignment offset.  */
                  bool range_list_added = false;
                  if (fde->in_std_section)
                    {
                      add_ranges_by_labels (subr_die,
                                            fde->dw_fde_begin,
                                            fde->dw_fde_end,
                                            &range_list_added);
                      add_ranges_by_labels (subr_die,
                                            fde->dw_fde_unlikely_section_label,
                                            fde->dw_fde_unlikely_section_end_label,
                                            &range_list_added);
                    }
                  else
                    {
                      add_ranges_by_labels (subr_die,
                                            fde->dw_fde_begin,
                                            fde->dw_fde_end,
                                            &range_list_added);
                      add_ranges_by_labels (subr_die,
                                            fde->dw_fde_hot_section_label,
                                            fde->dw_fde_hot_section_end_label,
                                            &range_list_added);
                    }
                  add_pubname (decl, subr_die);
                  if (range_list_added)
                    add_ranges (NULL);
                }
              else
                {
                  /* There is no real support in DW2 for this .. so we make
                     a work-around.  First, emit the pub name for the segment
                     containing the function label.  Then make and emit a
                     simplified subprogram DIE for the second segment with the
                     name pre-fixed by __hot/cold_sect_of_.  We use the same
                     linkage name for the second die so that gdb will find both
                     sections when given "b foo".  */
                  const char *name = NULL;
                  tree decl_name = DECL_NAME (decl);
                  dw_die_ref seg_die;

                  /* Do the 'primary' section.   */
                  add_AT_lbl_id (subr_die, DW_AT_low_pc,
                                 fde->dw_fde_begin);
                  add_AT_lbl_id (subr_die, DW_AT_high_pc,
                                 fde->dw_fde_end);
                  /* Add it.   */
                  add_pubname (decl, subr_die);
                  add_arange (decl, subr_die);

                  /* Build a minimal DIE for the secondary section.  */
                  seg_die = new_die (DW_TAG_subprogram,
                                     subr_die->die_parent, decl);

                  if (TREE_PUBLIC (decl))
                    add_AT_flag (seg_die, DW_AT_external, 1);

                  if (decl_name != NULL 
                      && IDENTIFIER_POINTER (decl_name) != NULL)
                    {
                      name = dwarf2_name (decl, 1);
                      if (! DECL_ARTIFICIAL (decl))
                        add_src_coords_attributes (seg_die, decl);

                      add_linkage_name (seg_die, decl);
                    }
                  gcc_assert (name!=NULL);
                  add_pure_or_virtual_attribute (seg_die, decl);
                  if (DECL_ARTIFICIAL (decl))
                    add_AT_flag (seg_die, DW_AT_artificial, 1);

                  if (fde->in_std_section)
                    {
                      name = concat ("__cold_sect_of_", name, NULL); 
                      add_AT_lbl_id (seg_die, DW_AT_low_pc,
                                     fde->dw_fde_unlikely_section_label);
                      add_AT_lbl_id (seg_die, DW_AT_high_pc,
                                     fde->dw_fde_unlikely_section_end_label); 
                    }
                  else 
                    {
                      name = concat ("__hot_sect_of_", name, NULL); 
                      add_AT_lbl_id (seg_die, DW_AT_low_pc,
                                     fde->dw_fde_hot_section_label);
                      add_AT_lbl_id (seg_die, DW_AT_high_pc,
                                     fde->dw_fde_hot_section_end_label); 
                    }
                  add_name_attribute (seg_die, name);
                  add_pubname_string (name, seg_die);
                  add_arange (decl, seg_die);
                }
            }
          else
            {
              add_AT_lbl_id (subr_die, DW_AT_low_pc, fde->dw_fde_begin);
              add_AT_lbl_id (subr_die, DW_AT_high_pc, fde->dw_fde_end);
              add_pubname (decl, subr_die);
              add_arange (decl, subr_die);
            }
        }

#ifdef MIPS_DEBUGGING_INFO
      /* Add a reference to the FDE for this routine.  */
      add_AT_fde_ref (subr_die, DW_AT_MIPS_fde, current_funcdef_fde);
#endif

      cfa_fb_offset = CFA_FRAME_BASE_OFFSET (decl);

      /* We define the "frame base" as the function's CFA.  This is more
         convenient for several reasons: (1) It's stable across the prologue
         and epilogue, which makes it better than just a frame pointer,
         (2) With dwarf3, there exists a one-byte encoding that allows us
         to reference the .debug_frame data by proxy, but failing that,
         (3) We can at least reuse the code inspection and interpretation
         code that determines the CFA position at various points in the
         function.  */
      if (dwarf_version >= 3)
        {
          dw_loc_descr_ref op = new_loc_descr (DW_OP_call_frame_cfa, 0, 0);
          add_AT_loc (subr_die, DW_AT_frame_base, op);
        }
      else
        {
          dw_loc_list_ref list = convert_cfa_to_fb_loc_list (cfa_fb_offset);
          if (list->dw_loc_next)
            add_AT_loc_list (subr_die, DW_AT_frame_base, list);
          else
            add_AT_loc (subr_die, DW_AT_frame_base, list->expr);
        }

      /* Compute a displacement from the "steady-state frame pointer" to
         the CFA.  The former is what all stack slots and argument slots
         will reference in the rtl; the later is what we've told the
         debugger about.  We'll need to adjust all frame_base references
         by this displacement.  */
      compute_frame_pointer_to_fb_displacement (cfa_fb_offset);

      if (cfun->static_chain_decl)
        add_AT_location_description (subr_die, DW_AT_static_link,
                 loc_list_from_tree (cfun->static_chain_decl, 2));
    }

  /* Generate child dies for template paramaters.  */
  if (debug_info_level > DINFO_LEVEL_TERSE)
    gen_generic_params_dies (decl);

  /* Now output descriptions of the arguments for this function. This gets
     (unnecessarily?) complex because of the fact that the DECL_ARGUMENT list
     for a FUNCTION_DECL doesn't indicate cases where there was a trailing
     `...' at the end of the formal parameter list.  In order to find out if
     there was a trailing ellipsis or not, we must instead look at the type
     associated with the FUNCTION_DECL.  This will be a node of type
     FUNCTION_TYPE. If the chain of type nodes hanging off of this
     FUNCTION_TYPE node ends with a void_type_node then there should *not* be
     an ellipsis at the end.  */

  /* In the case where we are describing a mere function declaration, all we
     need to do here (and all we *can* do here) is to describe the *types* of
     its formal parameters.  */
  if (debug_info_level <= DINFO_LEVEL_TERSE)
    ;
  else if (declaration)
    gen_formal_types_die (decl, subr_die);
  else
    {
      /* Generate DIEs to represent all known formal parameters.  */
      tree parm = DECL_ARGUMENTS (decl);
      tree generic_decl = lang_hooks.decls.get_generic_function_decl (decl);
      tree generic_decl_parm = generic_decl
                                ? DECL_ARGUMENTS (generic_decl)
                                : NULL;

      /* Now we want to walk the list of parameters of the function and
         emit their relevant DIEs.

         We consider the case of DECL being an instance of a generic function
         as well as it being a normal function.

         If DECL is an instance of a generic function we walk the
         parameters of the generic function declaration _and_ the parameters of
         DECL itself. This is useful because we want to emit specific DIEs for
         function parameter packs and those are declared as part of the
         generic function declaration. In that particular case,
         the parameter pack yields a DW_TAG_GNU_formal_parameter_pack DIE.
         That DIE has children DIEs representing the set of arguments
         of the pack. Note that the set of pack arguments can be empty.
         In that case, the DW_TAG_GNU_formal_parameter_pack DIE will not have any
         children DIE.

         Otherwise, we just consider the parameters of DECL.  */
      while (generic_decl_parm || parm)
        {
          if (generic_decl_parm
              && lang_hooks.function_parameter_pack_p (generic_decl_parm))
            gen_formal_parameter_pack_die (generic_decl_parm,
                                           parm, subr_die,
                                           &parm);
          else if (parm)
            {
              dw_die_ref parm_die = gen_decl_die (parm, NULL, subr_die);

              if (parm == DECL_ARGUMENTS (decl)
                  && TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE
                  && parm_die
                  && (dwarf_version >= 3 || !dwarf_strict))
                add_AT_die_ref (subr_die, DW_AT_object_pointer, parm_die);

              parm = DECL_CHAIN (parm);
            }

          if (generic_decl_parm)
            generic_decl_parm = DECL_CHAIN (generic_decl_parm);
        }

      /* Decide whether we need an unspecified_parameters DIE at the end.
         There are 2 more cases to do this for: 1) the ansi ... declaration -
         this is detectable when the end of the arg list is not a
         void_type_node 2) an unprototyped function declaration (not a
         definition).  This just means that we have no info about the
         parameters at all.  */
      if (prototype_p (TREE_TYPE (decl)))
        {
          /* This is the prototyped case, check for....  */
          if (stdarg_p (TREE_TYPE (decl)))
            gen_unspecified_parameters_die (decl, subr_die);
        }
      else if (DECL_INITIAL (decl) == NULL_TREE)
        gen_unspecified_parameters_die (decl, subr_die);
    }

  /* Output Dwarf info for all of the stuff within the body of the function
     (if it has one - it may be just a declaration).  */
  outer_scope = DECL_INITIAL (decl);

  /* OUTER_SCOPE is a pointer to the outermost BLOCK node created to represent
     a function.  This BLOCK actually represents the outermost binding contour
     for the function, i.e. the contour in which the function's formal
     parameters and labels get declared. Curiously, it appears that the front
     end doesn't actually put the PARM_DECL nodes for the current function onto
     the BLOCK_VARS list for this outer scope, but are strung off of the
     DECL_ARGUMENTS list for the function instead.

     The BLOCK_VARS list for the `outer_scope' does provide us with a list of
     the LABEL_DECL nodes for the function however, and we output DWARF info
     for those in decls_for_scope.  Just within the `outer_scope' there will be
     a BLOCK node representing the function's outermost pair of curly braces,
     and any blocks used for the base and member initializers of a C++
     constructor function.  */
  if (! declaration && TREE_CODE (outer_scope) != ERROR_MARK)
    {
      /* Emit a DW_TAG_variable DIE for a named return value.  */
      if (DECL_NAME (DECL_RESULT (decl)))
        gen_decl_die (DECL_RESULT (decl), NULL, subr_die);

      current_function_has_inlines = 0;
      decls_for_scope (outer_scope, subr_die, 0);
    }
  /* Add the calling convention attribute if requested.  */
  add_calling_convention_attribute (subr_die, decl);

}

/* Returns a hash value for X (which really is a die_struct).  */

static hashval_t
common_block_die_table_hash (const void *x)
{
  const_dw_die_ref d = (const_dw_die_ref) x;
  return (hashval_t) d->decl_id ^ htab_hash_pointer (d->die_parent);
}

/* Return nonzero if decl_id and die_parent of die_struct X is the same
   as decl_id and die_parent of die_struct Y.  */

static int
common_block_die_table_eq (const void *x, const void *y)
{
  const_dw_die_ref d = (const_dw_die_ref) x;
  const_dw_die_ref e = (const_dw_die_ref) y;
  return d->decl_id == e->decl_id && d->die_parent == e->die_parent;
}

/* Generate a DIE to represent a declared data object.
   Either DECL or ORIGIN must be non-null.  */

static void
gen_variable_die (tree decl, tree origin, dw_die_ref context_die)
{
  HOST_WIDE_INT off;
  tree com_decl;
  tree decl_or_origin = decl ? decl : origin;
  tree ultimate_origin;
  dw_die_ref var_die;
  dw_die_ref old_die = decl ? lookup_decl_die (decl) : NULL;
  dw_die_ref origin_die;
  bool declaration = (DECL_EXTERNAL (decl_or_origin)
                      || class_or_namespace_scope_p (context_die));
  bool specialization_p = false;

  ultimate_origin = decl_ultimate_origin (decl_or_origin);
  if (decl || ultimate_origin)
    origin = ultimate_origin;
  com_decl = fortran_common (decl_or_origin, &off);

  /* Symbol in common gets emitted as a child of the common block, in the form
     of a data member.  */
  if (com_decl)
    {
      dw_die_ref com_die;
      dw_loc_list_ref loc;
      die_node com_die_arg;

      var_die = lookup_decl_die (decl_or_origin);
      if (var_die)
        {
          if (get_AT (var_die, DW_AT_location) == NULL)
            {
              loc = loc_list_from_tree (com_decl, off ? 1 : 2);
              if (loc)
                {
                  if (off)
                    {
                      /* Optimize the common case.  */
                      if (single_element_loc_list_p (loc)
                          && loc->expr->dw_loc_opc == DW_OP_addr
                          && loc->expr->dw_loc_next == NULL
                          && GET_CODE (loc->expr->dw_loc_oprnd1.v.val_addr)
                             == SYMBOL_REF)
                        loc->expr->dw_loc_oprnd1.v.val_addr
                          = plus_constant (loc->expr->dw_loc_oprnd1.v.val_addr, off);
                        else
                          loc_list_plus_const (loc, off);
                    }
                  add_AT_location_description (var_die, DW_AT_location, loc);
                  remove_AT (var_die, DW_AT_declaration);
                }
            }
          return;
        }

      if (common_block_die_table == NULL)
        common_block_die_table
          = htab_create_ggc (10, common_block_die_table_hash,
                             common_block_die_table_eq, NULL);

      com_die_arg.decl_id = DECL_UID (com_decl);
      com_die_arg.die_parent = context_die;
      com_die = (dw_die_ref) htab_find (common_block_die_table, &com_die_arg);
      loc = loc_list_from_tree (com_decl, 2);
      if (com_die == NULL)
        {
          const char *cnam
            = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (com_decl));
          void **slot;

          com_die = new_die (DW_TAG_common_block, context_die, decl);
          add_name_and_src_coords_attributes (com_die, com_decl);
          if (loc)
            {
              add_AT_location_description (com_die, DW_AT_location, loc);
              /* Avoid sharing the same loc descriptor between
                 DW_TAG_common_block and DW_TAG_variable.  */
              loc = loc_list_from_tree (com_decl, 2);
            }
          else if (DECL_EXTERNAL (decl))
            add_AT_flag (com_die, DW_AT_declaration, 1);
          add_pubname_string (cnam, com_die); /* ??? needed? */
          com_die->decl_id = DECL_UID (com_decl);
          slot = htab_find_slot (common_block_die_table, com_die, INSERT);
          *slot = (void *) com_die;
        }
      else if (get_AT (com_die, DW_AT_location) == NULL && loc)
        {
          add_AT_location_description (com_die, DW_AT_location, loc);
          loc = loc_list_from_tree (com_decl, 2);
          remove_AT (com_die, DW_AT_declaration);
        }
      var_die = new_die (DW_TAG_variable, com_die, decl);
      add_name_and_src_coords_attributes (var_die, decl);
      add_type_attribute (var_die, TREE_TYPE (decl), TREE_READONLY (decl),
                          TREE_THIS_VOLATILE (decl), context_die);
      add_AT_flag (var_die, DW_AT_external, 1);
      if (loc)
        {
          if (off)
            {
              /* Optimize the common case.  */
              if (single_element_loc_list_p (loc)
                  && loc->expr->dw_loc_opc == DW_OP_addr
                  && loc->expr->dw_loc_next == NULL
                  && GET_CODE (loc->expr->dw_loc_oprnd1.v.val_addr) == SYMBOL_REF)
                loc->expr->dw_loc_oprnd1.v.val_addr
                  = plus_constant (loc->expr->dw_loc_oprnd1.v.val_addr, off);
              else
                loc_list_plus_const (loc, off);
            }
          add_AT_location_description (var_die, DW_AT_location, loc);
        }
      else if (DECL_EXTERNAL (decl))
        add_AT_flag (var_die, DW_AT_declaration, 1);
      equate_decl_number_to_die (decl, var_die);
      return;
    }

  /* If the compiler emitted a definition for the DECL declaration
     and if we already emitted a DIE for it, don't emit a second
     DIE for it again. Allow re-declarations of DECLs that are
     inside functions, though.  */
  if (old_die && declaration && !local_scope_p (context_die))
    return;

  /* For static data members, the declaration in the class is supposed
     to have DW_TAG_member tag; the specification should still be
     DW_TAG_variable referencing the DW_TAG_member DIE.  */
  if (declaration && class_scope_p (context_die))
    var_die = new_die (DW_TAG_member, context_die, decl);
  else
    var_die = new_die (DW_TAG_variable, context_die, decl);

  origin_die = NULL;
  if (origin != NULL)
    origin_die = add_abstract_origin_attribute (var_die, origin);

  /* Loop unrolling can create multiple blocks that refer to the same
     static variable, so we must test for the DW_AT_declaration flag.

     ??? Loop unrolling/reorder_blocks should perhaps be rewritten to
     copy decls and set the DECL_ABSTRACT flag on them instead of
     sharing them.

     ??? Duplicated blocks have been rewritten to use .debug_ranges.

     ??? The declare_in_namespace support causes us to get two DIEs for one
     variable, both of which are declarations.  We want to avoid considering
     one to be a specification, so we must test that this DIE is not a
     declaration.  */
  else if (old_die && TREE_STATIC (decl) && ! declaration
           && get_AT_flag (old_die, DW_AT_declaration) == 1)
    {
      /* This is a definition of a C++ class level static.  */
      add_AT_specification (var_die, old_die);
      specialization_p = true;
      if (DECL_NAME (decl))
        {
          expanded_location s = expand_location (DECL_SOURCE_LOCATION (decl));
          struct dwarf_file_data * file_index = lookup_filename (s.file);

          if (get_AT_file (old_die, DW_AT_decl_file) != file_index)
            add_AT_file (var_die, DW_AT_decl_file, file_index);

          if (get_AT_unsigned (old_die, DW_AT_decl_line) != (unsigned) s.line)
            add_AT_unsigned (var_die, DW_AT_decl_line, s.line);

          if (old_die->die_tag == DW_TAG_member)
            add_linkage_name (var_die, decl);
        }
    }
  else
    add_name_and_src_coords_attributes (var_die, decl);

  if ((origin == NULL && !specialization_p)
      || (origin != NULL
          && !DECL_ABSTRACT (decl_or_origin)
          && variably_modified_type_p (TREE_TYPE (decl_or_origin),
                                       decl_function_context
                                                        (decl_or_origin))))
    {
      tree type = TREE_TYPE (decl_or_origin);

      if (decl_by_reference_p (decl_or_origin))
        add_type_attribute (var_die, TREE_TYPE (type), 0, 0, context_die);
      else
        add_type_attribute (var_die, type, TREE_READONLY (decl_or_origin),
                            TREE_THIS_VOLATILE (decl_or_origin), context_die);
    }

  if (origin == NULL && !specialization_p)
    {
      if (TREE_PUBLIC (decl))
        add_AT_flag (var_die, DW_AT_external, 1);

      if (DECL_ARTIFICIAL (decl))
        add_AT_flag (var_die, DW_AT_artificial, 1);

      add_accessibility_attribute (var_die, decl);
    }

  if (declaration)
    add_AT_flag (var_die, DW_AT_declaration, 1);

  if (decl && (DECL_ABSTRACT (decl) || declaration || old_die == NULL))
    equate_decl_number_to_die (decl, var_die);

  if (! declaration
      && (! DECL_ABSTRACT (decl_or_origin)
          /* Local static vars are shared between all clones/inlines,
             so emit DW_AT_location on the abstract DIE if DECL_RTL is
             already set.  */
          || (TREE_CODE (decl_or_origin) == VAR_DECL
              && TREE_STATIC (decl_or_origin)
              && DECL_RTL_SET_P (decl_or_origin)))
      /* When abstract origin already has DW_AT_location attribute, no need
         to add it again.  */
      && (origin_die == NULL || get_AT (origin_die, DW_AT_location) == NULL))
    {
      if (TREE_CODE (decl_or_origin) == VAR_DECL && TREE_STATIC (decl_or_origin)
          && !TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl_or_origin)))
        defer_location (decl_or_origin, var_die);
      else
        add_location_or_const_value_attribute (var_die,
                                               decl_or_origin,
                                               DW_AT_location);
      add_pubname (decl_or_origin, var_die);
    }
  else
    tree_add_const_value_attribute_for_decl (var_die, decl_or_origin);
}

/* Generate a DIE to represent a named constant.  */

static void
gen_const_die (tree decl, dw_die_ref context_die)
{
  dw_die_ref const_die;
  tree type = TREE_TYPE (decl);

  const_die = new_die (DW_TAG_constant, context_die, decl);
  add_name_and_src_coords_attributes (const_die, decl);
  add_type_attribute (const_die, type, 1, 0, context_die);
  if (TREE_PUBLIC (decl))
    add_AT_flag (const_die, DW_AT_external, 1);
  if (DECL_ARTIFICIAL (decl))
    add_AT_flag (const_die, DW_AT_artificial, 1);
  tree_add_const_value_attribute_for_decl (const_die, decl);
}

/* Generate a DIE to represent a label identifier.  */

static void
gen_label_die (tree decl, dw_die_ref context_die)
{
  tree origin = decl_ultimate_origin (decl);
  dw_die_ref lbl_die = new_die (DW_TAG_label, context_die, decl);
  rtx insn;
  char label[MAX_ARTIFICIAL_LABEL_BYTES];

  if (origin != NULL)
    add_abstract_origin_attribute (lbl_die, origin);
  else
    add_name_and_src_coords_attributes (lbl_die, decl);

  if (DECL_ABSTRACT (decl))
    equate_decl_number_to_die (decl, lbl_die);
  else
    {
      insn = DECL_RTL_IF_SET (decl);

      /* Deleted labels are programmer specified labels which have been
         eliminated because of various optimizations.  We still emit them
         here so that it is possible to put breakpoints on them.  */
      if (insn
          && (LABEL_P (insn)
              || ((NOTE_P (insn)
                   && NOTE_KIND (insn) == NOTE_INSN_DELETED_LABEL))))
        {
          /* When optimization is enabled (via -O) some parts of the compiler
             (e.g. jump.c and cse.c) may try to delete CODE_LABEL insns which
             represent source-level labels which were explicitly declared by
             the user.  This really shouldn't be happening though, so catch
             it if it ever does happen.  */
          gcc_assert (!INSN_DELETED_P (insn));

          ASM_GENERATE_INTERNAL_LABEL (label, "L", CODE_LABEL_NUMBER (insn));
          add_AT_lbl_id (lbl_die, DW_AT_low_pc, label);
        }
    }
}

/* A helper function for gen_inlined_subroutine_die.  Add source coordinate
   attributes to the DIE for a block STMT, to describe where the inlined
   function was called from.  This is similar to add_src_coords_attributes.  */

static inline void
add_call_src_coords_attributes (tree stmt, dw_die_ref die)
{
  expanded_location s = expand_location (BLOCK_SOURCE_LOCATION (stmt));

  if (dwarf_version >= 3 || !dwarf_strict)
    {
      add_AT_file (die, DW_AT_call_file, lookup_filename (s.file));
      add_AT_unsigned (die, DW_AT_call_line, s.line);
    }
}


/* A helper function for gen_lexical_block_die and gen_inlined_subroutine_die.
   Add low_pc and high_pc attributes to the DIE for a block STMT.  */

static inline void
add_high_low_attributes (tree stmt, dw_die_ref die)
{
  char label[MAX_ARTIFICIAL_LABEL_BYTES];

  if (BLOCK_FRAGMENT_CHAIN (stmt)
      && (dwarf_version >= 3 || !dwarf_strict))
    {
      tree chain;

      if (inlined_function_outer_scope_p (stmt))
        {
          ASM_GENERATE_INTERNAL_LABEL (label, BLOCK_BEGIN_LABEL,
                                       BLOCK_NUMBER (stmt));
          add_AT_lbl_id (die, DW_AT_entry_pc, label);
        }

      add_AT_range_list (die, DW_AT_ranges, add_ranges (stmt));

      chain = BLOCK_FRAGMENT_CHAIN (stmt);
      do
        {
          add_ranges (chain);
          chain = BLOCK_FRAGMENT_CHAIN (chain);
        }
      while (chain);
      add_ranges (NULL);
    }
  else
    {
      ASM_GENERATE_INTERNAL_LABEL (label, BLOCK_BEGIN_LABEL,
                                   BLOCK_NUMBER (stmt));
      add_AT_lbl_id (die, DW_AT_low_pc, label);
      ASM_GENERATE_INTERNAL_LABEL (label, BLOCK_END_LABEL,
                                   BLOCK_NUMBER (stmt));
      add_AT_lbl_id (die, DW_AT_high_pc, label);
    }
}

/* Generate a DIE for a lexical block.  */

static void
gen_lexical_block_die (tree stmt, dw_die_ref context_die, int depth)
{
  dw_die_ref stmt_die = new_die (DW_TAG_lexical_block, context_die, stmt);

  if (! BLOCK_ABSTRACT (stmt) && TREE_ASM_WRITTEN (stmt))
    add_high_low_attributes (stmt, stmt_die);

  decls_for_scope (stmt, stmt_die, depth);
}

/* Generate a DIE for an inlined subprogram.  */

static void
gen_inlined_subroutine_die (tree stmt, dw_die_ref context_die, int depth)
{
  tree decl;

  /* The instance of function that is effectively being inlined shall not
     be abstract.  */
  gcc_assert (! BLOCK_ABSTRACT (stmt));

  decl = block_ultimate_origin (stmt);

  /* Emit info for the abstract instance first, if we haven't yet.  We
     must emit this even if the block is abstract, otherwise when we
     emit the block below (or elsewhere), we may end up trying to emit
     a die whose origin die hasn't been emitted, and crashing.  */
  dwarf2out_abstract_function (decl);

  if (! BLOCK_ABSTRACT (stmt))
    {
      dw_die_ref subr_die
        = new_die (DW_TAG_inlined_subroutine, context_die, stmt);

      add_abstract_origin_attribute (subr_die, decl);
      if (TREE_ASM_WRITTEN (stmt))
        add_high_low_attributes (stmt, subr_die);
      add_call_src_coords_attributes (stmt, subr_die);

      decls_for_scope (stmt, subr_die, depth);
      current_function_has_inlines = 1;
    }
}

/* Generate a DIE for a field in a record, or structure.  */

static void
gen_field_die (tree decl, dw_die_ref context_die)
{
  dw_die_ref decl_die;

  if (TREE_TYPE (decl) == error_mark_node)
    return;

  decl_die = new_die (DW_TAG_member, context_die, decl);
  add_name_and_src_coords_attributes (decl_die, decl);
  add_type_attribute (decl_die, member_declared_type (decl),
                      TREE_READONLY (decl), TREE_THIS_VOLATILE (decl),
                      context_die);

  if (DECL_BIT_FIELD_TYPE (decl))
    {
      add_byte_size_attribute (decl_die, decl);
      add_bit_size_attribute (decl_die, decl);
      add_bit_offset_attribute (decl_die, decl);
    }

  if (TREE_CODE (DECL_FIELD_CONTEXT (decl)) != UNION_TYPE)
    add_data_member_location_attribute (decl_die, decl);

  if (DECL_ARTIFICIAL (decl))
    add_AT_flag (decl_die, DW_AT_artificial, 1);

  add_accessibility_attribute (decl_die, decl);

  /* Equate decl number to die, so that we can look up this decl later on.  */
  equate_decl_number_to_die (decl, decl_die);
}

#if 0
/* Don't generate either pointer_type DIEs or reference_type DIEs here.
   Use modified_type_die instead.
   We keep this code here just in case these types of DIEs may be needed to
   represent certain things in other languages (e.g. Pascal) someday.  */

static void
gen_pointer_type_die (tree type, dw_die_ref context_die)
{
  dw_die_ref ptr_die
    = new_die (DW_TAG_pointer_type, scope_die_for (type, context_die), type);

  equate_type_number_to_die (type, ptr_die);
  add_type_attribute (ptr_die, TREE_TYPE (type), 0, 0, context_die);
  add_AT_unsigned (mod_type_die, DW_AT_byte_size, PTR_SIZE);
}

/* Don't generate either pointer_type DIEs or reference_type DIEs here.
   Use modified_type_die instead.
   We keep this code here just in case these types of DIEs may be needed to
   represent certain things in other languages (e.g. Pascal) someday.  */

static void
gen_reference_type_die (tree type, dw_die_ref context_die)
{
  dw_die_ref ref_die, scope_die = scope_die_for (type, context_die);

  if (TYPE_REF_IS_RVALUE (type) && dwarf_version >= 4)
    ref_die = new_die (DW_TAG_rvalue_reference_type, scope_die, type);
  else
    ref_die = new_die (DW_TAG_reference_type, scope_die, type);

  equate_type_number_to_die (type, ref_die);
  add_type_attribute (ref_die, TREE_TYPE (type), 0, 0, context_die);
  add_AT_unsigned (mod_type_die, DW_AT_byte_size, PTR_SIZE);
}
#endif

/* Generate a DIE for a pointer to a member type.  */

static void
gen_ptr_to_mbr_type_die (tree type, dw_die_ref context_die)
{
  dw_die_ref ptr_die
    = new_die (DW_TAG_ptr_to_member_type,
               scope_die_for (type, context_die), type);

  equate_type_number_to_die (type, ptr_die);
  add_AT_die_ref (ptr_die, DW_AT_containing_type,
                  lookup_type_die (TYPE_OFFSET_BASETYPE (type)));
  add_type_attribute (ptr_die, TREE_TYPE (type), 0, 0, context_die);
}

/* Generate the DIE for the compilation unit.  */

static dw_die_ref
gen_compile_unit_die (const char *filename)
{
  dw_die_ref die;
  char producer[250];
  const char *language_string = lang_hooks.name;
  int language;

  die = new_die (DW_TAG_compile_unit, NULL, NULL);

  if (filename)
    {
      add_name_attribute (die, filename);
      /* Don't add cwd for <built-in>.  */
      if (!IS_ABSOLUTE_PATH (filename) && filename[0] != '<')
        add_comp_dir_attribute (die);
    }

  sprintf (producer, "%s %s", language_string, version_string);

#ifdef MIPS_DEBUGGING_INFO
  /* The MIPS/SGI compilers place the 'cc' command line options in the producer
     string.  The SGI debugger looks for -g, -g1, -g2, or -g3; if they do
     not appear in the producer string, the debugger reaches the conclusion
     that the object file is stripped and has no debugging information.
     To get the MIPS/SGI debugger to believe that there is debugging
     information in the object file, we add a -g to the producer string.  */
  if (debug_info_level > DINFO_LEVEL_TERSE)
    strcat (producer, " -g");
#endif

  add_AT_string (die, DW_AT_producer, producer);

  /* If our producer is LTO try to figure out a common language to use
     from the global list of translation units.  */
  if (strcmp (language_string, "GNU GIMPLE") == 0)
    {
      unsigned i;
      tree t;
      const char *common_lang = NULL;

      FOR_EACH_VEC_ELT (tree, all_translation_units, i, t)
        {
          if (!TRANSLATION_UNIT_LANGUAGE (t))
            continue;
          if (!common_lang)
            common_lang = TRANSLATION_UNIT_LANGUAGE (t);
          else if (strcmp (common_lang, TRANSLATION_UNIT_LANGUAGE (t)) == 0)
            ;
          else if (strncmp (common_lang, "GNU C", 5) == 0
                   && strncmp (TRANSLATION_UNIT_LANGUAGE (t), "GNU C", 5) == 0)
            /* Mixing C and C++ is ok, use C++ in that case.  */
            common_lang = "GNU C++";
          else
            {
              /* Fall back to C.  */
              common_lang = NULL;
              break;
            }
        }

      if (common_lang)
        language_string = common_lang;
    }

  language = DW_LANG_C89;
  if (strcmp (language_string, "GNU C++") == 0)
    language = DW_LANG_C_plus_plus;
  else if (strcmp (language_string, "GNU F77") == 0)
    language = DW_LANG_Fortran77;
  else if (strcmp (language_string, "GNU Pascal") == 0)
    language = DW_LANG_Pascal83;
  else if (dwarf_version >= 3 || !dwarf_strict)
    {
      if (strcmp (language_string, "GNU Ada") == 0)
        language = DW_LANG_Ada95;
      else if (strcmp (language_string, "GNU Fortran") == 0)
        language = DW_LANG_Fortran95;
      else if (strcmp (language_string, "GNU Java") == 0)
        language = DW_LANG_Java;
      else if (strcmp (language_string, "GNU Objective-C") == 0)
        language = DW_LANG_ObjC;
      else if (strcmp (language_string, "GNU Objective-C++") == 0)
        language = DW_LANG_ObjC_plus_plus;
    }

  add_AT_unsigned (die, DW_AT_language, language);

  switch (language)
    {
    case DW_LANG_Fortran77:
    case DW_LANG_Fortran90:
    case DW_LANG_Fortran95:
      /* Fortran has case insensitive identifiers and the front-end
         lowercases everything.  */
      add_AT_unsigned (die, DW_AT_identifier_case, DW_ID_down_case);
      break;
    default:
      /* The default DW_ID_case_sensitive doesn't need to be specified.  */
      break;
    }
  return die;
}

/* Generate the DIE for a base class.  */

static void
gen_inheritance_die (tree binfo, tree access, dw_die_ref context_die)
{
  dw_die_ref die = new_die (DW_TAG_inheritance, context_die, binfo);

  add_type_attribute (die, BINFO_TYPE (binfo), 0, 0, context_die);
  add_data_member_location_attribute (die, binfo);

  if (BINFO_VIRTUAL_P (binfo))
    add_AT_unsigned (die, DW_AT_virtuality, DW_VIRTUALITY_virtual);

  /* In DWARF3+ the default is DW_ACCESS_private only in DW_TAG_class_type
     children, otherwise the default is DW_ACCESS_public.  In DWARF2
     the default has always been DW_ACCESS_private.  */
  if (access == access_public_node)
    {
      if (dwarf_version == 2
          || context_die->die_tag == DW_TAG_class_type)
      add_AT_unsigned (die, DW_AT_accessibility, DW_ACCESS_public);
    }
  else if (access == access_protected_node)
    add_AT_unsigned (die, DW_AT_accessibility, DW_ACCESS_protected);
  else if (dwarf_version > 2
           && context_die->die_tag != DW_TAG_class_type)
    add_AT_unsigned (die, DW_AT_accessibility, DW_ACCESS_private);
}

/* Generate a DIE for a class member.  */

static void
gen_member_die (tree type, dw_die_ref context_die)
{
  tree member;
  tree binfo = TYPE_BINFO (type);
  dw_die_ref child;

  /* If this is not an incomplete type, output descriptions of each of its
     members. Note that as we output the DIEs necessary to represent the
     members of this record or union type, we will also be trying to output
     DIEs to represent the *types* of those members. However the `type'
     function (above) will specifically avoid generating type DIEs for member
     types *within* the list of member DIEs for this (containing) type except
     for those types (of members) which are explicitly marked as also being
     members of this (containing) type themselves.  The g++ front- end can
     force any given type to be treated as a member of some other (containing)
     type by setting the TYPE_CONTEXT of the given (member) type to point to
     the TREE node representing the appropriate (containing) type.  */

  /* First output info about the base classes.  */
  if (binfo)
    {
      VEC(tree,gc) *accesses = BINFO_BASE_ACCESSES (binfo);
      int i;
      tree base;

      for (i = 0; BINFO_BASE_ITERATE (binfo, i, base); i++)
        gen_inheritance_die (base,
                             (accesses ? VEC_index (tree, accesses, i)
                              : access_public_node), context_die);
    }

  /* Now output info about the data members and type members.  */
  for (member = TYPE_FIELDS (type); member; member = DECL_CHAIN (member))
    {
      /* If we thought we were generating minimal debug info for TYPE
         and then changed our minds, some of the member declarations
         may have already been defined.  Don't define them again, but
         do put them in the right order.  */

      child = lookup_decl_die (member);
      if (child)
        splice_child_die (context_die, child);
      else
        gen_decl_die (member, NULL, context_die);
    }

  /* Now output info about the function members (if any).  */
  for (member = TYPE_METHODS (type); member; member = DECL_CHAIN (member))
    {
      /* Don't include clones in the member list.  */
      if (DECL_ABSTRACT_ORIGIN (member))
        continue;

      child = lookup_decl_die (member);
      if (child)
        splice_child_die (context_die, child);
      else
        gen_decl_die (member, NULL, context_die);
    }
}

/* Generate a DIE for a structure or union type.  If TYPE_DECL_SUPPRESS_DEBUG
   is set, we pretend that the type was never defined, so we only get the
   member DIEs needed by later specification DIEs.  */

static void
gen_struct_or_union_type_die (tree type, dw_die_ref context_die,
                                enum debug_info_usage usage)
{
  dw_die_ref type_die = lookup_type_die (type);
  dw_die_ref scope_die = 0;
  int nested = 0;
  int complete = (TYPE_SIZE (type)
                  && (! TYPE_STUB_DECL (type)
                      || ! TYPE_DECL_SUPPRESS_DEBUG (TYPE_STUB_DECL (type))));
  int ns_decl = (context_die && context_die->die_tag == DW_TAG_namespace);
  complete = complete && should_emit_struct_debug (type, usage);

  if (type_die && ! complete)
    return;

  if (TYPE_CONTEXT (type) != NULL_TREE
      && (AGGREGATE_TYPE_P (TYPE_CONTEXT (type))
          || TREE_CODE (TYPE_CONTEXT (type)) == NAMESPACE_DECL))
    nested = 1;

  scope_die = scope_die_for (type, context_die);

  if (! type_die || (nested && is_cu_die (scope_die)))
    /* First occurrence of type or toplevel definition of nested class.  */
    {
      dw_die_ref old_die = type_die;

      type_die = new_die (TREE_CODE (type) == RECORD_TYPE
                          ? record_type_tag (type) : DW_TAG_union_type,
                          scope_die, type);
      equate_type_number_to_die (type, type_die);
      if (old_die)
        add_AT_specification (type_die, old_die);
      else
        add_name_attribute (type_die, type_tag (type));
    }
  else
    remove_AT (type_die, DW_AT_declaration);

  /* Generate child dies for template paramaters.  */
  if (debug_info_level > DINFO_LEVEL_TERSE
      && COMPLETE_TYPE_P (type))
    gen_generic_params_dies (type);

  /* If this type has been completed, then give it a byte_size attribute and
     then give a list of members.  */
  if (complete && !ns_decl)
    {
      /* Prevent infinite recursion in cases where the type of some member of
         this type is expressed in terms of this type itself.  */
      TREE_ASM_WRITTEN (type) = 1;
      add_byte_size_attribute (type_die, type);
      if (TYPE_STUB_DECL (type) != NULL_TREE)
        {
          add_src_coords_attributes (type_die, TYPE_STUB_DECL (type));
          add_accessibility_attribute (type_die, TYPE_STUB_DECL (type));
        }

      /* If the first reference to this type was as the return type of an
         inline function, then it may not have a parent.  Fix this now.  */
      if (type_die->die_parent == NULL)
        add_child_die (scope_die, type_die);

      push_decl_scope (type);
      gen_member_die (type, type_die);
      pop_decl_scope ();

      /* GNU extension: Record what type our vtable lives in.  */
      if (TYPE_VFIELD (type))
        {
          tree vtype = DECL_FCONTEXT (TYPE_VFIELD (type));

          gen_type_die (vtype, context_die);
          add_AT_die_ref (type_die, DW_AT_containing_type,
                          lookup_type_die (vtype));
        }
    }
  else
    {
      add_AT_flag (type_die, DW_AT_declaration, 1);

      /* We don't need to do this for function-local types.  */
      if (TYPE_STUB_DECL (type)
          && ! decl_function_context (TYPE_STUB_DECL (type)))
        VEC_safe_push (tree, gc, incomplete_types, type);
    }

  if (get_AT (type_die, DW_AT_name))
    add_pubtype (type, type_die);
}

/* Generate a DIE for a subroutine _type_.  */

static void
gen_subroutine_type_die (tree type, dw_die_ref context_die)
{
  tree return_type = TREE_TYPE (type);
  dw_die_ref subr_die
    = new_die (DW_TAG_subroutine_type,
               scope_die_for (type, context_die), type);

  equate_type_number_to_die (type, subr_die);
  add_prototyped_attribute (subr_die, type);
  add_type_attribute (subr_die, return_type, 0, 0, context_die);
  gen_formal_types_die (type, subr_die);

  if (get_AT (subr_die, DW_AT_name))
    add_pubtype (type, subr_die);
}

/* Generate a DIE for a type definition.  */

static void
gen_typedef_die (tree decl, dw_die_ref context_die)
{
  dw_die_ref type_die;
  tree origin;

  if (TREE_ASM_WRITTEN (decl))
    return;

  TREE_ASM_WRITTEN (decl) = 1;
  type_die = new_die (DW_TAG_typedef, context_die, decl);
  origin = decl_ultimate_origin (decl);
  if (origin != NULL)
    add_abstract_origin_attribute (type_die, origin);
  else
    {
      tree type;

      add_name_and_src_coords_attributes (type_die, decl);
      if (DECL_ORIGINAL_TYPE (decl))
        {
          type = DECL_ORIGINAL_TYPE (decl);

          gcc_assert (type != TREE_TYPE (decl));
          equate_type_number_to_die (TREE_TYPE (decl), type_die);
        }
      else
        {
          type = TREE_TYPE (decl);

          if (is_naming_typedef_decl (TYPE_NAME (type)))
            {
              /* Here, we are in the case of decl being a typedef naming
                 an anonymous type, e.g:
                     typedef struct {...} foo;
                 In that case TREE_TYPE (decl) is not a typedef variant
                 type and TYPE_NAME of the anonymous type is set to the
                 TYPE_DECL of the typedef. This construct is emitted by
                 the C++ FE.

                 TYPE is the anonymous struct named by the typedef
                 DECL. As we need the DW_AT_type attribute of the
                 DW_TAG_typedef to point to the DIE of TYPE, let's
                 generate that DIE right away. add_type_attribute
                 called below will then pick (via lookup_type_die) that
                 anonymous struct DIE.  */
              if (!TREE_ASM_WRITTEN (type))
                gen_tagged_type_die (type, context_die, DINFO_USAGE_DIR_USE);
            }
        }

      add_type_attribute (type_die, type, TREE_READONLY (decl),
                          TREE_THIS_VOLATILE (decl), context_die);

      if (is_naming_typedef_decl (decl))
        /* We want that all subsequent calls to lookup_type_die with
           TYPE in argument yield the DW_TAG_typedef we have just
           created.  */
        equate_type_number_to_die (type, type_die);

      add_accessibility_attribute (type_die, decl);
    }

  if (DECL_ABSTRACT (decl))
    equate_decl_number_to_die (decl, type_die);

  if (get_AT (type_die, DW_AT_name))
    add_pubtype (decl, type_die);
}

/* Generate a DIE for a struct, class, enum or union type.  */

static void
gen_tagged_type_die (tree type,
                     dw_die_ref context_die,
                     enum debug_info_usage usage)
{
  int need_pop;

  if (type == NULL_TREE
      || !is_tagged_type (type))
    return;

  /* If this is a nested type whose containing class hasn't been written
     out yet, writing it out will cover this one, too.  This does not apply
     to instantiations of member class templates; they need to be added to
     the containing class as they are generated.  FIXME: This hurts the
     idea of combining type decls from multiple TUs, since we can't predict
     what set of template instantiations we'll get.  */
  if (TYPE_CONTEXT (type)
      && AGGREGATE_TYPE_P (TYPE_CONTEXT (type))
      && ! TREE_ASM_WRITTEN (TYPE_CONTEXT (type)))
    {
      gen_type_die_with_usage (TYPE_CONTEXT (type), context_die, usage);

      if (TREE_ASM_WRITTEN (type))
        return;

      /* If that failed, attach ourselves to the stub.  */
      push_decl_scope (TYPE_CONTEXT (type));
      context_die = lookup_type_die (TYPE_CONTEXT (type));
      need_pop = 1;
    }
  else if (TYPE_CONTEXT (type) != NULL_TREE
           && (TREE_CODE (TYPE_CONTEXT (type)) == FUNCTION_DECL))
    {
      /* If this type is local to a function that hasn't been written
         out yet, use a NULL context for now; it will be fixed up in
         decls_for_scope.  */
      context_die = lookup_decl_die (TYPE_CONTEXT (type));
      /* A declaration DIE doesn't count; nested types need to go in the
         specification.  */
      if (context_die && is_declaration_die (context_die))
        context_die = NULL;
      need_pop = 0;
    }
  else
    {
      context_die = declare_in_namespace (type, context_die);
      need_pop = 0;
    }

  if (TREE_CODE (type) == ENUMERAL_TYPE)
    {
      /* This might have been written out by the call to
         declare_in_namespace.  */
      if (!TREE_ASM_WRITTEN (type))
        gen_enumeration_type_die (type, context_die);
    }
  else
    gen_struct_or_union_type_die (type, context_die, usage);

  if (need_pop)
    pop_decl_scope ();

  /* Don't set TREE_ASM_WRITTEN on an incomplete struct; we want to fix
     it up if it is ever completed.  gen_*_type_die will set it for us
     when appropriate.  */
}

/* Generate a type description DIE.  */

static void
gen_type_die_with_usage (tree type, dw_die_ref context_die,
                         enum debug_info_usage usage)
{
  struct array_descr_info info;

  if (type == NULL_TREE || type == error_mark_node)
    return;

  if (TYPE_NAME (type) != NULL_TREE
      && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
      && is_redundant_typedef (TYPE_NAME (type))
      && DECL_ORIGINAL_TYPE (TYPE_NAME (type)))
    /* The DECL of this type is a typedef we don't want to emit debug
       info for but we want debug info for its underlying typedef.
       This can happen for e.g, the injected-class-name of a C++
       type.  */
    type = DECL_ORIGINAL_TYPE (TYPE_NAME (type));

  /* If TYPE is a typedef type variant, let's generate debug info
     for the parent typedef which TYPE is a type of.  */
  if (typedef_variant_p (type))
    {
      if (TREE_ASM_WRITTEN (type))
        return;

      /* Prevent broken recursion; we can't hand off to the same type.  */
      gcc_assert (DECL_ORIGINAL_TYPE (TYPE_NAME (type)) != type);

      /* Use the DIE of the containing namespace as the parent DIE of
         the type description DIE we want to generate.  */
      if (DECL_CONTEXT (TYPE_NAME (type))
          && TREE_CODE (DECL_CONTEXT (TYPE_NAME (type))) == NAMESPACE_DECL)
        context_die = get_context_die (DECL_CONTEXT (TYPE_NAME (type)));

      TREE_ASM_WRITTEN (type) = 1;

      gen_decl_die (TYPE_NAME (type), NULL, context_die);
      return;
    }

  /* If type is an anonymous tagged type named by a typedef, let's
     generate debug info for the typedef.  */
  if (is_naming_typedef_decl (TYPE_NAME (type)))
    {
      /* Use the DIE of the containing namespace as the parent DIE of
         the type description DIE we want to generate.  */
      if (DECL_CONTEXT (TYPE_NAME (type))
          && TREE_CODE (DECL_CONTEXT (TYPE_NAME (type))) == NAMESPACE_DECL)
        context_die = get_context_die (DECL_CONTEXT (TYPE_NAME (type)));
      
      gen_decl_die (TYPE_NAME (type), NULL, context_die);
      return;
    }

  /* If this is an array type with hidden descriptor, handle it first.  */
  if (!TREE_ASM_WRITTEN (type)
      && lang_hooks.types.get_array_descr_info
      && lang_hooks.types.get_array_descr_info (type, &info)
      && (dwarf_version >= 3 || !dwarf_strict))
    {
      gen_descr_array_type_die (type, &info, context_die);
      TREE_ASM_WRITTEN (type) = 1;
      return;
    }

  /* We are going to output a DIE to represent the unqualified version
     of this type (i.e. without any const or volatile qualifiers) so
     get the main variant (i.e. the unqualified version) of this type
     now.  (Vectors are special because the debugging info is in the
     cloned type itself).  */
  if (TREE_CODE (type) != VECTOR_TYPE)
    type = type_main_variant (type);

  if (TREE_ASM_WRITTEN (type))
    return;

  switch (TREE_CODE (type))
    {
    case ERROR_MARK:
      break;

    case POINTER_TYPE:
    case REFERENCE_TYPE:
      /* We must set TREE_ASM_WRITTEN in case this is a recursive type.  This
         ensures that the gen_type_die recursion will terminate even if the
         type is recursive.  Recursive types are possible in Ada.  */
      /* ??? We could perhaps do this for all types before the switch
         statement.  */
      TREE_ASM_WRITTEN (type) = 1;

      /* For these types, all that is required is that we output a DIE (or a
         set of DIEs) to represent the "basis" type.  */
      gen_type_die_with_usage (TREE_TYPE (type), context_die,
                                DINFO_USAGE_IND_USE);
      break;

    case OFFSET_TYPE:
      /* This code is used for C++ pointer-to-data-member types.
         Output a description of the relevant class type.  */
      gen_type_die_with_usage (TYPE_OFFSET_BASETYPE (type), context_die,
                                        DINFO_USAGE_IND_USE);

      /* Output a description of the type of the object pointed to.  */
      gen_type_die_with_usage (TREE_TYPE (type), context_die,
                                        DINFO_USAGE_IND_USE);

      /* Now output a DIE to represent this pointer-to-data-member type
         itself.  */
      gen_ptr_to_mbr_type_die (type, context_die);
      break;

    case FUNCTION_TYPE:
      /* Force out return type (in case it wasn't forced out already).  */
      gen_type_die_with_usage (TREE_TYPE (type), context_die,
                                        DINFO_USAGE_DIR_USE);
      gen_subroutine_type_die (type, context_die);
      break;

    case METHOD_TYPE:
      /* Force out return type (in case it wasn't forced out already).  */
      gen_type_die_with_usage (TREE_TYPE (type), context_die,
                                        DINFO_USAGE_DIR_USE);
      gen_subroutine_type_die (type, context_die);
      break;

    case ARRAY_TYPE:
      gen_array_type_die (type, context_die);
      break;

    case VECTOR_TYPE:
      gen_array_type_die (type, context_die);
      break;

    case ENUMERAL_TYPE:
    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      gen_tagged_type_die (type, context_die, usage);
      return;

    case VOID_TYPE:
    case INTEGER_TYPE:
    case REAL_TYPE:
    case FIXED_POINT_TYPE:
    case COMPLEX_TYPE:
    case BOOLEAN_TYPE:
      /* No DIEs needed for fundamental types.  */
      break;

    case NULLPTR_TYPE:
    case LANG_TYPE:
      /* Just use DW_TAG_unspecified_type.  */
      {
        dw_die_ref type_die = lookup_type_die (type);
        if (type_die == NULL)
          {
            tree name = TYPE_NAME (type);
            if (TREE_CODE (name) == TYPE_DECL)
              name = DECL_NAME (name);
            type_die = new_die (DW_TAG_unspecified_type, comp_unit_die (), type);
            add_name_attribute (type_die, IDENTIFIER_POINTER (name));
            equate_type_number_to_die (type, type_die);
          }
      }
      break;

    default:
      gcc_unreachable ();
    }

  TREE_ASM_WRITTEN (type) = 1;
}

static void
gen_type_die (tree type, dw_die_ref context_die)
{
  gen_type_die_with_usage (type, context_die, DINFO_USAGE_DIR_USE);
}

/* Generate a DW_TAG_lexical_block DIE followed by DIEs to represent all of the
   things which are local to the given block.  */

static void
gen_block_die (tree stmt, dw_die_ref context_die, int depth)
{
  int must_output_die = 0;
  bool inlined_func;

  /* Ignore blocks that are NULL.  */
  if (stmt == NULL_TREE)
    return;

  inlined_func = inlined_function_outer_scope_p (stmt);

  /* If the block is one fragment of a non-contiguous block, do not
     process the variables, since they will have been done by the
     origin block.  Do process subblocks.  */
  if (BLOCK_FRAGMENT_ORIGIN (stmt))
    {
      tree sub;

      for (sub = BLOCK_SUBBLOCKS (stmt); sub; sub = BLOCK_CHAIN (sub))
        gen_block_die (sub, context_die, depth + 1);

      return;
    }

  /* Determine if we need to output any Dwarf DIEs at all to represent this
     block.  */
  if (inlined_func)
    /* The outer scopes for inlinings *must* always be represented.  We
       generate DW_TAG_inlined_subroutine DIEs for them.  (See below.) */
    must_output_die = 1;
  else
    {
      /* Determine if this block directly contains any "significant"
         local declarations which we will need to output DIEs for.  */
      if (debug_info_level > DINFO_LEVEL_TERSE)
        /* We are not in terse mode so *any* local declaration counts
           as being a "significant" one.  */
        must_output_die = ((BLOCK_VARS (stmt) != NULL
                            || BLOCK_NUM_NONLOCALIZED_VARS (stmt))
                           && (TREE_USED (stmt)
                               || TREE_ASM_WRITTEN (stmt)
                               || BLOCK_ABSTRACT (stmt)));
      else if ((TREE_USED (stmt)
                || TREE_ASM_WRITTEN (stmt)
                || BLOCK_ABSTRACT (stmt))
               && !dwarf2out_ignore_block (stmt))
        must_output_die = 1;
    }

  /* It would be a waste of space to generate a Dwarf DW_TAG_lexical_block
     DIE for any block which contains no significant local declarations at
     all.  Rather, in such cases we just call `decls_for_scope' so that any
     needed Dwarf info for any sub-blocks will get properly generated. Note
     that in terse mode, our definition of what constitutes a "significant"
     local declaration gets restricted to include only inlined function
     instances and local (nested) function definitions.  */
  if (must_output_die)
    {
      if (inlined_func)
        {
          /* If STMT block is abstract, that means we have been called
             indirectly from dwarf2out_abstract_function.
             That function rightfully marks the descendent blocks (of
             the abstract function it is dealing with) as being abstract,
             precisely to prevent us from emitting any
             DW_TAG_inlined_subroutine DIE as a descendent
             of an abstract function instance. So in that case, we should
             not call gen_inlined_subroutine_die.

             Later though, when cgraph asks dwarf2out to emit info
             for the concrete instance of the function decl into which
             the concrete instance of STMT got inlined, the later will lead
             to the generation of a DW_TAG_inlined_subroutine DIE.  */
          if (! BLOCK_ABSTRACT (stmt))
            gen_inlined_subroutine_die (stmt, context_die, depth);
        }
      else
        gen_lexical_block_die (stmt, context_die, depth);
    }
  else
    decls_for_scope (stmt, context_die, depth);
}

/* Process variable DECL (or variable with origin ORIGIN) within
   block STMT and add it to CONTEXT_DIE.  */
static void
process_scope_var (tree stmt, tree decl, tree origin, dw_die_ref context_die)
{
  dw_die_ref die;
  tree decl_or_origin = decl ? decl : origin;

  if (TREE_CODE (decl_or_origin) == FUNCTION_DECL)
    die = lookup_decl_die (decl_or_origin);
  else if (TREE_CODE (decl_or_origin) == TYPE_DECL
           && TYPE_DECL_IS_STUB (decl_or_origin))
    die = lookup_type_die (TREE_TYPE (decl_or_origin));
  else
    die = NULL;

  if (die != NULL && die->die_parent == NULL)
    add_child_die (context_die, die);
  else if (TREE_CODE (decl_or_origin) == IMPORTED_DECL)
    dwarf2out_imported_module_or_decl_1 (decl_or_origin, DECL_NAME (decl_or_origin),
                                         stmt, context_die);
  else
    gen_decl_die (decl, origin, context_die);
}

/* Generate all of the decls declared within a given scope and (recursively)
   all of its sub-blocks.  */

static void
decls_for_scope (tree stmt, dw_die_ref context_die, int depth)
{
  tree decl;
  unsigned int i;
  tree subblocks;

  /* Ignore NULL blocks.  */
  if (stmt == NULL_TREE)
    return;

  /* Output the DIEs to represent all of the data objects and typedefs
     declared directly within this block but not within any nested
     sub-blocks.  Also, nested function and tag DIEs have been
     generated with a parent of NULL; fix that up now.  */
  for (decl = BLOCK_VARS (stmt); decl != NULL; decl = DECL_CHAIN (decl))
    process_scope_var (stmt, decl, NULL_TREE, context_die);
  for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (stmt); i++)
    process_scope_var (stmt, NULL, BLOCK_NONLOCALIZED_VAR (stmt, i),
                       context_die);

  /* If we're at -g1, we're not interested in subblocks.  */
  if (debug_info_level <= DINFO_LEVEL_TERSE)
    return;

  /* Output the DIEs to represent all sub-blocks (and the items declared
     therein) of this block.  */
  for (subblocks = BLOCK_SUBBLOCKS (stmt);
       subblocks != NULL;
       subblocks = BLOCK_CHAIN (subblocks))
    gen_block_die (subblocks, context_die, depth + 1);
}

/* Is this a typedef we can avoid emitting?  */

static inline int
is_redundant_typedef (const_tree decl)
{
  if (TYPE_DECL_IS_STUB (decl))
    return 1;

  if (DECL_ARTIFICIAL (decl)
      && DECL_CONTEXT (decl)
      && is_tagged_type (DECL_CONTEXT (decl))
      && TREE_CODE (TYPE_NAME (DECL_CONTEXT (decl))) == TYPE_DECL
      && DECL_NAME (decl) == DECL_NAME (TYPE_NAME (DECL_CONTEXT (decl))))
    /* Also ignore the artificial member typedef for the class name.  */
    return 1;

  return 0;
}

/* Return TRUE if TYPE is a typedef that names a type for linkage
   purposes. This kind of typedefs is produced by the C++ FE for
   constructs like:

   typedef struct {...} foo;

   In that case, there is no typedef variant type produced for foo.
   Rather, the TREE_TYPE of the TYPE_DECL of foo is the anonymous
   struct type.  */

static bool
is_naming_typedef_decl (const_tree decl)
{
  if (decl == NULL_TREE
      || TREE_CODE (decl) != TYPE_DECL
      || !is_tagged_type (TREE_TYPE (decl))
      || DECL_IS_BUILTIN (decl)
      || is_redundant_typedef (decl)
      /* It looks like Ada produces TYPE_DECLs that are very similar
         to C++ naming typedefs but that have different
         semantics. Let's be specific to c++ for now.  */
      || !is_cxx ())
    return FALSE;

  return (DECL_ORIGINAL_TYPE (decl) == NULL_TREE
          && TYPE_NAME (TREE_TYPE (decl)) == decl
          && (TYPE_STUB_DECL (TREE_TYPE (decl))
              != TYPE_NAME (TREE_TYPE (decl))));
}

/* Returns the DIE for a context.  */

static inline dw_die_ref
get_context_die (tree context)
{
  if (context)
    {
      /* Find die that represents this context.  */
      if (TYPE_P (context))
        return force_type_die (TYPE_MAIN_VARIANT (context));
      else
        return force_decl_die (context);
    }
  return comp_unit_die ();
}

/* Returns the DIE for decl.  A DIE will always be returned.  */

static dw_die_ref
force_decl_die (tree decl)
{
  dw_die_ref decl_die;
  unsigned saved_external_flag;
  tree save_fn = NULL_TREE;
  decl_die = lookup_decl_die (decl);
  if (!decl_die)
    {
      dw_die_ref context_die = get_context_die (DECL_CONTEXT (decl));

      decl_die = lookup_decl_die (decl);
      if (decl_die)
        return decl_die;

      switch (TREE_CODE (decl))
        {
        case FUNCTION_DECL:
          /* Clear current_function_decl, so that gen_subprogram_die thinks
             that this is a declaration. At this point, we just want to force
             declaration die.  */
          save_fn = current_function_decl;
          current_function_decl = NULL_TREE;
          gen_subprogram_die (decl, context_die);
          current_function_decl = save_fn;
          break;

        case VAR_DECL:
          /* Set external flag to force declaration die. Restore it after
           gen_decl_die() call.  */
          saved_external_flag = DECL_EXTERNAL (decl);
          DECL_EXTERNAL (decl) = 1;
          gen_decl_die (decl, NULL, context_die);
          DECL_EXTERNAL (decl) = saved_external_flag;
          break;

        case NAMESPACE_DECL:
          if (dwarf_version >= 3 || !dwarf_strict)
            dwarf2out_decl (decl);
          else
            /* DWARF2 has neither DW_TAG_module, nor DW_TAG_namespace.  */
            decl_die = comp_unit_die ();
          break;

        case TRANSLATION_UNIT_DECL:
          decl_die = comp_unit_die ();
          break;

        default:
          gcc_unreachable ();
        }

      /* We should be able to find the DIE now.  */
      if (!decl_die)
        decl_die = lookup_decl_die (decl);
      gcc_assert (decl_die);
    }

  return decl_die;
}

/* Returns the DIE for TYPE, that must not be a base type.  A DIE is
   always returned.  */

static dw_die_ref
force_type_die (tree type)
{
  dw_die_ref type_die;

  type_die = lookup_type_die (type);
  if (!type_die)
    {
      dw_die_ref context_die = get_context_die (TYPE_CONTEXT (type));

      type_die = modified_type_die (type, TYPE_READONLY (type),
                                    TYPE_VOLATILE (type), context_die);
      gcc_assert (type_die);
    }
  return type_die;
}

/* Force out any required namespaces to be able to output DECL,
   and return the new context_die for it, if it's changed.  */

static dw_die_ref
setup_namespace_context (tree thing, dw_die_ref context_die)
{
  tree context = (DECL_P (thing)
                  ? DECL_CONTEXT (thing) : TYPE_CONTEXT (thing));
  if (context && TREE_CODE (context) == NAMESPACE_DECL)
    /* Force out the namespace.  */
    context_die = force_decl_die (context);

  return context_die;
}

/* Emit a declaration DIE for THING (which is either a DECL or a tagged
   type) within its namespace, if appropriate.

   For compatibility with older debuggers, namespace DIEs only contain
   declarations; all definitions are emitted at CU scope.  */

static dw_die_ref
declare_in_namespace (tree thing, dw_die_ref context_die)
{
  dw_die_ref ns_context;

  if (debug_info_level <= DINFO_LEVEL_TERSE)
    return context_die;

  /* If this decl is from an inlined function, then don't try to emit it in its
     namespace, as we will get confused.  It would have already been emitted
     when the abstract instance of the inline function was emitted anyways.  */
  if (DECL_P (thing) && DECL_ABSTRACT_ORIGIN (thing))
    return context_die;

  ns_context = setup_namespace_context (thing, context_die);

  if (ns_context != context_die)
    {
      if (is_fortran ())
        return ns_context;
      if (DECL_P (thing))
        gen_decl_die (thing, NULL, ns_context);
      else
        gen_type_die (thing, ns_context);
    }
  return context_die;
}

/* Generate a DIE for a namespace or namespace alias.  */

static void
gen_namespace_die (tree decl, dw_die_ref context_die)
{
  dw_die_ref namespace_die;

  /* Namespace aliases have a DECL_ABSTRACT_ORIGIN of the namespace
     they are an alias of.  */
  if (DECL_ABSTRACT_ORIGIN (decl) == NULL)
    {
      /* Output a real namespace or module.  */
      context_die = setup_namespace_context (decl, comp_unit_die ());
      namespace_die = new_die (is_fortran ()
                               ? DW_TAG_module : DW_TAG_namespace,
                               context_die, decl);
      /* For Fortran modules defined in different CU don't add src coords.  */
      if (namespace_die->die_tag == DW_TAG_module && DECL_EXTERNAL (decl))
        {
          const char *name = dwarf2_name (decl, 0);
          if (name)
            add_name_attribute (namespace_die, name);
        }
      else
        add_name_and_src_coords_attributes (namespace_die, decl);
      if (DECL_EXTERNAL (decl))
        add_AT_flag (namespace_die, DW_AT_declaration, 1);
      equate_decl_number_to_die (decl, namespace_die);
    }
  else
    {
      /* Output a namespace alias.  */

      /* Force out the namespace we are an alias of, if necessary.  */
      dw_die_ref origin_die
        = force_decl_die (DECL_ABSTRACT_ORIGIN (decl));

      if (DECL_FILE_SCOPE_P (decl)
          || TREE_CODE (DECL_CONTEXT (decl)) == NAMESPACE_DECL)
        context_die = setup_namespace_context (decl, comp_unit_die ());
      /* Now create the namespace alias DIE.  */
      namespace_die = new_die (DW_TAG_imported_declaration, context_die, decl);
      add_name_and_src_coords_attributes (namespace_die, decl);
      add_AT_die_ref (namespace_die, DW_AT_import, origin_die);
      equate_decl_number_to_die (decl, namespace_die);
    }
}

/* Generate Dwarf debug information for a decl described by DECL.
   The return value is currently only meaningful for PARM_DECLs,
   for all other decls it returns NULL.  */

static dw_die_ref
gen_decl_die (tree decl, tree origin, dw_die_ref context_die)
{
  tree decl_or_origin = decl ? decl : origin;
  tree class_origin = NULL, ultimate_origin;

  if (DECL_P (decl_or_origin) && DECL_IGNORED_P (decl_or_origin))
    return NULL;

  switch (TREE_CODE (decl_or_origin))
    {
    case ERROR_MARK:
      break;

    case CONST_DECL:
      if (!is_fortran () && !is_ada ())
        {
          /* The individual enumerators of an enum type get output when we output
             the Dwarf representation of the relevant enum type itself.  */
          break;
        }

      /* Emit its type.  */
      gen_type_die (TREE_TYPE (decl), context_die);

      /* And its containing namespace.  */
      context_die = declare_in_namespace (decl, context_die);

      gen_const_die (decl, context_die);
      break;

    case FUNCTION_DECL:
      /* Don't output any DIEs to represent mere function declarations,
         unless they are class members or explicit block externs.  */
      if (DECL_INITIAL (decl_or_origin) == NULL_TREE
          && DECL_FILE_SCOPE_P (decl_or_origin)
          && (current_function_decl == NULL_TREE
              || DECL_ARTIFICIAL (decl_or_origin)))
        break;

#if 0
      /* FIXME */
      /* This doesn't work because the C frontend sets DECL_ABSTRACT_ORIGIN
         on local redeclarations of global functions.  That seems broken.  */
      if (current_function_decl != decl)
        /* This is only a declaration.  */;
#endif

      /* If we're emitting a clone, emit info for the abstract instance.  */
      if (origin || DECL_ORIGIN (decl) != decl)
        dwarf2out_abstract_function (origin
                                     ? DECL_ORIGIN (origin)
                                     : DECL_ABSTRACT_ORIGIN (decl));

      /* If we're emitting an out-of-line copy of an inline function,
         emit info for the abstract instance and set up to refer to it.  */
      else if (cgraph_function_possibly_inlined_p (decl)
               && ! DECL_ABSTRACT (decl)
               && ! class_or_namespace_scope_p (context_die)
               /* dwarf2out_abstract_function won't emit a die if this is just
                  a declaration.  We must avoid setting DECL_ABSTRACT_ORIGIN in
                  that case, because that works only if we have a die.  */
               && DECL_INITIAL (decl) != NULL_TREE)
        {
          dwarf2out_abstract_function (decl);
          set_decl_origin_self (decl);
        }

      /* Otherwise we're emitting the primary DIE for this decl.  */
      else if (debug_info_level > DINFO_LEVEL_TERSE)
        {
          /* Before we describe the FUNCTION_DECL itself, make sure that we
             have its containing type.  */
          if (!origin)
            origin = decl_class_context (decl);
          if (origin != NULL_TREE)
            gen_type_die (origin, context_die);

          /* And its return type.  */
          gen_type_die (TREE_TYPE (TREE_TYPE (decl)), context_die);

          /* And its virtual context.  */
          if (DECL_VINDEX (decl) != NULL_TREE)
            gen_type_die (DECL_CONTEXT (decl), context_die);

          /* Make sure we have a member DIE for decl.  */
          if (origin != NULL_TREE)
            gen_type_die_for_member (origin, decl, context_die);

          /* And its containing namespace.  */
          context_die = declare_in_namespace (decl, context_die);
        }

      /* Now output a DIE to represent the function itself.  */
      if (decl)
        gen_subprogram_die (decl, context_die);
      break;

    case TYPE_DECL:
      /* If we are in terse mode, don't generate any DIEs to represent any
         actual typedefs.  */
      if (debug_info_level <= DINFO_LEVEL_TERSE)
        break;

      /* In the special case of a TYPE_DECL node representing the declaration
         of some type tag, if the given TYPE_DECL is marked as having been
         instantiated from some other (original) TYPE_DECL node (e.g. one which
         was generated within the original definition of an inline function) we
         used to generate a special (abbreviated) DW_TAG_structure_type,
         DW_TAG_union_type, or DW_TAG_enumeration_type DIE here.  But nothing
         should be actually referencing those DIEs, as variable DIEs with that
         type would be emitted already in the abstract origin, so it was always
         removed during unused type prunning.  Don't add anything in this
         case.  */
      if (TYPE_DECL_IS_STUB (decl) && decl_ultimate_origin (decl) != NULL_TREE)
        break;

      if (is_redundant_typedef (decl))
        gen_type_die (TREE_TYPE (decl), context_die);
      else
        /* Output a DIE to represent the typedef itself.  */
        gen_typedef_die (decl, context_die);
      break;

    case LABEL_DECL:
      if (debug_info_level >= DINFO_LEVEL_NORMAL)
        gen_label_die (decl, context_die);
      break;

    case VAR_DECL:
    case RESULT_DECL:
      /* If we are in terse mode, don't generate any DIEs to represent any
         variable declarations or definitions.  */
      if (debug_info_level <= DINFO_LEVEL_TERSE)
        break;

      /* Output any DIEs that are needed to specify the type of this data
         object.  */
      if (decl_by_reference_p (decl_or_origin))
        gen_type_die (TREE_TYPE (TREE_TYPE (decl_or_origin)), context_die);
      else
        gen_type_die (TREE_TYPE (decl_or_origin), context_die);

      /* And its containing type.  */
      class_origin = decl_class_context (decl_or_origin);
      if (class_origin != NULL_TREE)
        gen_type_die_for_member (class_origin, decl_or_origin, context_die);

      /* And its containing namespace.  */
      context_die = declare_in_namespace (decl_or_origin, context_die);

      /* Now output the DIE to represent the data object itself.  This gets
         complicated because of the possibility that the VAR_DECL really
         represents an inlined instance of a formal parameter for an inline
         function.  */
      ultimate_origin = decl_ultimate_origin (decl_or_origin);
      if (ultimate_origin != NULL_TREE
          && TREE_CODE (ultimate_origin) == PARM_DECL)
        gen_formal_parameter_die (decl, origin,
                                  true /* Emit name attribute.  */,
                                  context_die);
      else
        gen_variable_die (decl, origin, context_die);
      break;

    case FIELD_DECL:
      /* Ignore the nameless fields that are used to skip bits but handle C++
         anonymous unions and structs.  */
      if (DECL_NAME (decl) != NULL_TREE
          || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
          || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE)
        {
          gen_type_die (member_declared_type (decl), context_die);
          gen_field_die (decl, context_die);
        }
      break;

    case PARM_DECL:
      if (DECL_BY_REFERENCE (decl_or_origin))
        gen_type_die (TREE_TYPE (TREE_TYPE (decl_or_origin)), context_die);
      else
        gen_type_die (TREE_TYPE (decl_or_origin), context_die);
      return gen_formal_parameter_die (decl, origin,
                                       true /* Emit name attribute.  */,
                                       context_die);

    case NAMESPACE_DECL:
    case IMPORTED_DECL:
      if (dwarf_version >= 3 || !dwarf_strict)
        gen_namespace_die (decl, context_die);
      break;

    default:
      /* Probably some frontend-internal decl.  Assume we don't care.  */
      gcc_assert ((int)TREE_CODE (decl) > NUM_TREE_CODES);
      break;
    }

  return NULL;
}
\f
/* Output debug information for global decl DECL.  Called from toplev.c after
   compilation proper has finished.  */

static void
dwarf2out_global_decl (tree decl)
{
  /* Output DWARF2 information for file-scope tentative data object
     declarations, file-scope (extern) function declarations (which
     had no corresponding body) and file-scope tagged type declarations
     and definitions which have not yet been forced out.  */
  if (TREE_CODE (decl) != FUNCTION_DECL || !DECL_INITIAL (decl))
    dwarf2out_decl (decl);
}

/* Output debug information for type decl DECL.  Called from toplev.c
   and from language front ends (to record built-in types).  */
static void
dwarf2out_type_decl (tree decl, int local)
{
  if (!local)
    dwarf2out_decl (decl);
}

/* Output debug information for imported module or decl DECL.
   NAME is non-NULL name in the lexical block if the decl has been renamed.
   LEXICAL_BLOCK is the lexical block (which TREE_CODE is a BLOCK)
   that DECL belongs to.
   LEXICAL_BLOCK_DIE is the DIE of LEXICAL_BLOCK.  */
static void
dwarf2out_imported_module_or_decl_1 (tree decl,
                                     tree name,
                                     tree lexical_block,
                                     dw_die_ref lexical_block_die)
{
  expanded_location xloc;
  dw_die_ref imported_die = NULL;
  dw_die_ref at_import_die;

  if (TREE_CODE (decl) == IMPORTED_DECL)
    {
      xloc = expand_location (DECL_SOURCE_LOCATION (decl));
      decl = IMPORTED_DECL_ASSOCIATED_DECL (decl);
      gcc_assert (decl);
    }
  else
    xloc = expand_location (input_location);

  if (TREE_CODE (decl) == TYPE_DECL || TREE_CODE (decl) == CONST_DECL)
    {
      at_import_die = force_type_die (TREE_TYPE (decl));
      /* For namespace N { typedef void T; } using N::T; base_type_die
         returns NULL, but DW_TAG_imported_declaration requires
         the DW_AT_import tag.  Force creation of DW_TAG_typedef.  */
      if (!at_import_die)
        {
          gcc_assert (TREE_CODE (decl) == TYPE_DECL);
          gen_typedef_die (decl, get_context_die (DECL_CONTEXT (decl)));
          at_import_die = lookup_type_die (TREE_TYPE (decl));
          gcc_assert (at_import_die);
        }
    }
  else
    {
      at_import_die = lookup_decl_die (decl);
      if (!at_import_die)
        {
          /* If we're trying to avoid duplicate debug info, we may not have
             emitted the member decl for this field.  Emit it now.  */
          if (TREE_CODE (decl) == FIELD_DECL)
            {
              tree type = DECL_CONTEXT (decl);

              if (TYPE_CONTEXT (type)
                  && TYPE_P (TYPE_CONTEXT (type))
                  && !should_emit_struct_debug (TYPE_CONTEXT (type),
                                                DINFO_USAGE_DIR_USE))
                return;
              gen_type_die_for_member (type, decl,
                                       get_context_die (TYPE_CONTEXT (type)));
            }
          at_import_die = force_decl_die (decl);
        }
    }

  if (TREE_CODE (decl) == NAMESPACE_DECL)
    {
      if (dwarf_version >= 3 || !dwarf_strict)
        imported_die = new_die (DW_TAG_imported_module,
                                lexical_block_die,
                                lexical_block);
      else
        return;
    }
  else
    imported_die = new_die (DW_TAG_imported_declaration,
                            lexical_block_die,
                            lexical_block);

  add_AT_file (imported_die, DW_AT_decl_file, lookup_filename (xloc.file));
  add_AT_unsigned (imported_die, DW_AT_decl_line, xloc.line);
  if (name)
    add_AT_string (imported_die, DW_AT_name,
                   IDENTIFIER_POINTER (name));
  add_AT_die_ref (imported_die, DW_AT_import, at_import_die);
}

/* Output debug information for imported module or decl DECL.
   NAME is non-NULL name in context if the decl has been renamed.
   CHILD is true if decl is one of the renamed decls as part of
   importing whole module.  */

static void
dwarf2out_imported_module_or_decl (tree decl, tree name, tree context,
                                   bool child)
{
  /* dw_die_ref at_import_die;  */
  dw_die_ref scope_die;

  if (debug_info_level <= DINFO_LEVEL_TERSE)
    return;

  gcc_assert (decl);

  /* To emit DW_TAG_imported_module or DW_TAG_imported_decl, we need two DIEs.
     We need decl DIE for reference and scope die. First, get DIE for the decl
     itself.  */

  /* Get the scope die for decl context. Use comp_unit_die for global module
     or decl. If die is not found for non globals, force new die.  */
  if (context
      && TYPE_P (context)
      && !should_emit_struct_debug (context, DINFO_USAGE_DIR_USE))
    return;

  if (!(dwarf_version >= 3 || !dwarf_strict))
    return;

  scope_die = get_context_die (context);

  if (child)
    {
      gcc_assert (scope_die->die_child);
      gcc_assert (scope_die->die_child->die_tag == DW_TAG_imported_module);
      gcc_assert (TREE_CODE (decl) != NAMESPACE_DECL);
      scope_die = scope_die->die_child;
    }

  /* OK, now we have DIEs for decl as well as scope. Emit imported die.  */
  dwarf2out_imported_module_or_decl_1 (decl, name, context, scope_die);

}

/* Write the debugging output for DECL.  */

void
dwarf2out_decl (tree decl)
{
  dw_die_ref context_die = comp_unit_die ();

  switch (TREE_CODE (decl))
    {
    case ERROR_MARK:
      return;

    case FUNCTION_DECL:
      /* What we would really like to do here is to filter out all mere
         file-scope declarations of file-scope functions which are never
         referenced later within this translation unit (and keep all of ones
         that *are* referenced later on) but we aren't clairvoyant, so we have
         no idea which functions will be referenced in the future (i.e. later
         on within the current translation unit). So here we just ignore all
         file-scope function declarations which are not also definitions.  If
         and when the debugger needs to know something about these functions,
         it will have to hunt around and find the DWARF information associated
         with the definition of the function.

         We can't just check DECL_EXTERNAL to find out which FUNCTION_DECL
         nodes represent definitions and which ones represent mere
         declarations.  We have to check DECL_INITIAL instead. That's because
         the C front-end supports some weird semantics for "extern inline"
         function definitions.  These can get inlined within the current
         translation unit (and thus, we need to generate Dwarf info for their
         abstract instances so that the Dwarf info for the concrete inlined
         instances can have something to refer to) but the compiler never
         generates any out-of-lines instances of such things (despite the fact
         that they *are* definitions).

         The important point is that the C front-end marks these "extern
         inline" functions as DECL_EXTERNAL, but we need to generate DWARF for
         them anyway. Note that the C++ front-end also plays some similar games
         for inline function definitions appearing within include files which
         also contain `#pragma interface' pragmas.  */
      if (DECL_INITIAL (decl) == NULL_TREE)
        return;

      /* If we're a nested function, initially use a parent of NULL; if we're
         a plain function, this will be fixed up in decls_for_scope.  If
         we're a method, it will be ignored, since we already have a DIE.  */
      if (decl_function_context (decl)
          /* But if we're in terse mode, we don't care about scope.  */
          && debug_info_level > DINFO_LEVEL_TERSE)
        context_die = NULL;
      break;

    case VAR_DECL:
      /* Ignore this VAR_DECL if it refers to a file-scope extern data object
         declaration and if the declaration was never even referenced from
         within this entire compilation unit.  We suppress these DIEs in
         order to save space in the .debug section (by eliminating entries
         which are probably useless).  Note that we must not suppress
         block-local extern declarations (whether used or not) because that
         would screw-up the debugger's name lookup mechanism and cause it to
         miss things which really ought to be in scope at a given point.  */
      if (DECL_EXTERNAL (decl) && !TREE_USED (decl))
        return;

      /* For local statics lookup proper context die.  */
      if (TREE_STATIC (decl) && decl_function_context (decl))
        context_die = lookup_decl_die (DECL_CONTEXT (decl));

      /* If we are in terse mode, don't generate any DIEs to represent any
         variable declarations or definitions.  */
      if (debug_info_level <= DINFO_LEVEL_TERSE)
        return;
      break;

    case CONST_DECL:
      if (debug_info_level <= DINFO_LEVEL_TERSE)
        return;
      if (!is_fortran () && !is_ada ())
        return;
      if (TREE_STATIC (decl) && decl_function_context (decl))
        context_die = lookup_decl_die (DECL_CONTEXT (decl));
      break;

    case NAMESPACE_DECL:
    case IMPORTED_DECL:
      if (debug_info_level <= DINFO_LEVEL_TERSE)
        return;
      if (lookup_decl_die (decl) != NULL)
        return;
      break;

    case TYPE_DECL:
      /* Don't emit stubs for types unless they are needed by other DIEs.  */
      if (TYPE_DECL_SUPPRESS_DEBUG (decl))
        return;

      /* Don't bother trying to generate any DIEs to represent any of the
         normal built-in types for the language we are compiling.  */
      if (DECL_IS_BUILTIN (decl))
        return;

      /* If we are in terse mode, don't generate any DIEs for types.  */
      if (debug_info_level <= DINFO_LEVEL_TERSE)
        return;

      /* If we're a function-scope tag, initially use a parent of NULL;
         this will be fixed up in decls_for_scope.  */
      if (decl_function_context (decl))
        context_die = NULL;

      break;

    default:
      return;
    }

  gen_decl_die (decl, NULL, context_die);
}

/* Write the debugging output for DECL.  */

static void
dwarf2out_function_decl (tree decl)
{
  dwarf2out_decl (decl);

  htab_empty (decl_loc_table);
}

/* Output a marker (i.e. a label) for the beginning of the generated code for
   a lexical block.  */

static void
dwarf2out_begin_block (unsigned int line ATTRIBUTE_UNUSED,
                       unsigned int blocknum)
{
  switch_to_section (current_function_section ());
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, BLOCK_BEGIN_LABEL, blocknum);
}

/* Output a marker (i.e. a label) for the end of the generated code for a
   lexical block.  */

static void
dwarf2out_end_block (unsigned int line ATTRIBUTE_UNUSED, unsigned int blocknum)
{
  switch_to_section (current_function_section ());
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, BLOCK_END_LABEL, blocknum);
}

/* Returns nonzero if it is appropriate not to emit any debugging
   information for BLOCK, because it doesn't contain any instructions.

   Don't allow this for blocks with nested functions or local classes
   as we would end up with orphans, and in the presence of scheduling
   we may end up calling them anyway.  */

static bool
dwarf2out_ignore_block (const_tree block)
{
  tree decl;
  unsigned int i;

  for (decl = BLOCK_VARS (block); decl; decl = DECL_CHAIN (decl))
    if (TREE_CODE (decl) == FUNCTION_DECL
        || (TREE_CODE (decl) == TYPE_DECL && TYPE_DECL_IS_STUB (decl)))
      return 0;
  for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (block); i++)
    {
      decl = BLOCK_NONLOCALIZED_VAR (block, i);
      if (TREE_CODE (decl) == FUNCTION_DECL
          || (TREE_CODE (decl) == TYPE_DECL && TYPE_DECL_IS_STUB (decl)))
      return 0;
    }

  return 1;
}

/* Hash table routines for file_hash.  */

static int
file_table_eq (const void *p1_p, const void *p2_p)
{
  const struct dwarf_file_data *const p1 =
    (const struct dwarf_file_data *) p1_p;
  const char *const p2 = (const char *) p2_p;
  return strcmp (p1->filename, p2) == 0;
}

static hashval_t
file_table_hash (const void *p_p)
{
  const struct dwarf_file_data *const p = (const struct dwarf_file_data *) p_p;
  return htab_hash_string (p->filename);
}

/* Lookup FILE_NAME (in the list of filenames that we know about here in
   dwarf2out.c) and return its "index".  The index of each (known) filename is
   just a unique number which is associated with only that one filename.  We
   need such numbers for the sake of generating labels (in the .debug_sfnames
   section) and references to those files numbers (in the .debug_srcinfo
   and.debug_macinfo sections).  If the filename given as an argument is not
   found in our current list, add it to the list and assign it the next
   available unique index number.  In order to speed up searches, we remember
   the index of the filename was looked up last.  This handles the majority of
   all searches.  */

static struct dwarf_file_data *
lookup_filename (const char *file_name)
{
  void ** slot;
  struct dwarf_file_data * created;

  /* Check to see if the file name that was searched on the previous
     call matches this file name.  If so, return the index.  */
  if (file_table_last_lookup
      && (file_name == file_table_last_lookup->filename
          || strcmp (file_table_last_lookup->filename, file_name) == 0))
    return file_table_last_lookup;

  /* Didn't match the previous lookup, search the table.  */
  slot = htab_find_slot_with_hash (file_table, file_name,
                                   htab_hash_string (file_name), INSERT);
  if (*slot)
    return (struct dwarf_file_data *) *slot;

  created = ggc_alloc_dwarf_file_data ();
  created->filename = file_name;
  created->emitted_number = 0;
  *slot = created;
  return created;
}

/* If the assembler will construct the file table, then translate the compiler
   internal file table number into the assembler file table number, and emit
   a .file directive if we haven't already emitted one yet.  The file table
   numbers are different because we prune debug info for unused variables and
   types, which may include filenames.  */

static int
maybe_emit_file (struct dwarf_file_data * fd)
{
  if (! fd->emitted_number)
    {
      if (last_emitted_file)
        fd->emitted_number = last_emitted_file->emitted_number + 1;
      else
        fd->emitted_number = 1;
      last_emitted_file = fd;

      if (DWARF2_ASM_LINE_DEBUG_INFO)
        {
          fprintf (asm_out_file, "\t.file %u ", fd->emitted_number);
          output_quoted_string (asm_out_file,
                                remap_debug_filename (fd->filename));
          fputc ('\n', asm_out_file);
        }
    }

  return fd->emitted_number;
}

/* Schedule generation of a DW_AT_const_value attribute to DIE.
   That generation should happen after function debug info has been
   generated. The value of the attribute is the constant value of ARG.  */

static void
append_entry_to_tmpl_value_parm_die_table (dw_die_ref die, tree arg)
{
  die_arg_entry entry;

  if (!die || !arg)
    return;

  if (!tmpl_value_parm_die_table)
    tmpl_value_parm_die_table
      = VEC_alloc (die_arg_entry, gc, 32);

  entry.die = die;
  entry.arg = arg;
  VEC_safe_push (die_arg_entry, gc,
                 tmpl_value_parm_die_table,
                 &entry);
}

/* Add a DW_AT_const_value attribute to DIEs that were scheduled
   by append_entry_to_tmpl_value_parm_die_table. This function must
   be called after function DIEs have been generated.  */

static void
gen_remaining_tmpl_value_param_die_attribute (void)
{
  if (tmpl_value_parm_die_table)
    {
      unsigned i;
      die_arg_entry *e;

      FOR_EACH_VEC_ELT (die_arg_entry, tmpl_value_parm_die_table, i, e)
        tree_add_const_value_attribute (e->die, e->arg);
    }
}


/* Replace DW_AT_name for the decl with name.  */

static void
dwarf2out_set_name (tree decl, tree name)
{
  dw_die_ref die;
  dw_attr_ref attr;
  const char *dname;

  die = TYPE_SYMTAB_DIE (decl);
  if (!die)
    return;

  dname = dwarf2_name (name, 0);
  if (!dname)
    return;

  attr = get_AT (die, DW_AT_name);
  if (attr)
    {
      struct indirect_string_node *node;

      node = find_AT_string (dname);
      /* replace the string.  */
      attr->dw_attr_val.v.val_str = node;
    }

  else
    add_name_attribute (die, dname);
}

/* Called by the final INSN scan whenever we see a direct function call.
   Make an entry into the direct call table, recording the point of call
   and a reference to the target function's debug entry.  */

static void
dwarf2out_direct_call (tree targ)
{
  dcall_entry e;
  tree origin = decl_ultimate_origin (targ);

  /* If this is a clone, use the abstract origin as the target.  */
  if (origin)
    targ = origin;

  e.poc_label_num = poc_label_num++;
  e.poc_decl = current_function_decl;
  e.targ_die = force_decl_die (targ);
  VEC_safe_push (dcall_entry, gc, dcall_table, &e);

  /* Drop a label at the return point to mark the point of call.  */
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, "LPOC", e.poc_label_num);
}

/* Returns a hash value for X (which really is a struct vcall_insn).  */

static hashval_t
vcall_insn_table_hash (const void *x)
{
  return (hashval_t) ((const struct vcall_insn *) x)->insn_uid;
}

/* Return nonzero if insn_uid of struct vcall_insn *X is the same as
   insnd_uid of *Y.  */

static int
vcall_insn_table_eq (const void *x, const void *y)
{
  return (((const struct vcall_insn *) x)->insn_uid
          == ((const struct vcall_insn *) y)->insn_uid);
}

/* Associate VTABLE_SLOT with INSN_UID in the VCALL_INSN_TABLE.  */

static void
store_vcall_insn (unsigned int vtable_slot, int insn_uid)
{
  struct vcall_insn *item = ggc_alloc_vcall_insn ();
  struct vcall_insn **slot;

  gcc_assert (item);
  item->insn_uid = insn_uid;
  item->vtable_slot = vtable_slot;
  slot = (struct vcall_insn **)
      htab_find_slot_with_hash (vcall_insn_table, &item,
                                (hashval_t) insn_uid, INSERT);
  *slot = item;
}

/* Return the VTABLE_SLOT associated with INSN_UID.  */

static unsigned int
lookup_vcall_insn (unsigned int insn_uid)
{
  struct vcall_insn item;
  struct vcall_insn *p;

  item.insn_uid = insn_uid;
  item.vtable_slot = 0;
  p = (struct vcall_insn *) htab_find_with_hash (vcall_insn_table,
                                                 (void *) &item,
                                                 (hashval_t) insn_uid);
  if (p == NULL)
    return (unsigned int) -1;
  return p->vtable_slot;
}


/* Called when lowering indirect calls to RTL.  We make a note of INSN_UID
   and the OBJ_TYPE_REF_TOKEN from ADDR.  For C++ virtual calls, the token
   is the vtable slot index that we will need to put in the virtual call
   table later.  */

static void
dwarf2out_virtual_call_token (tree addr, int insn_uid)
{
  if (is_cxx() && TREE_CODE (addr) == OBJ_TYPE_REF)
    {
      tree token = OBJ_TYPE_REF_TOKEN (addr);
      if (TREE_CODE (token) == INTEGER_CST)
        store_vcall_insn (TREE_INT_CST_LOW (token), insn_uid);
    }
}

/* Called when scheduling RTL, when a CALL_INSN is split.  Copies the
   OBJ_TYPE_REF_TOKEN previously associated with OLD_INSN and associates it
   with NEW_INSN.  */

static void
dwarf2out_copy_call_info (rtx old_insn, rtx new_insn)
{
  unsigned int vtable_slot = lookup_vcall_insn (INSN_UID (old_insn));

  if (vtable_slot != (unsigned int) -1)
    store_vcall_insn (vtable_slot, INSN_UID (new_insn));
}

/* Called by the final INSN scan whenever we see a virtual function call.
   Make an entry into the virtual call table, recording the point of call
   and the slot index of the vtable entry used to call the virtual member
   function.  The slot index was associated with the INSN_UID during the
   lowering to RTL.  */

static void
dwarf2out_virtual_call (int insn_uid)
{
  unsigned int vtable_slot = lookup_vcall_insn (insn_uid);
  vcall_entry e;

  if (vtable_slot == (unsigned int) -1)
    return;

  e.poc_label_num = poc_label_num++;
  e.vtable_slot = vtable_slot;
  VEC_safe_push (vcall_entry, gc, vcall_table, &e);

  /* Drop a label at the return point to mark the point of call.  */
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, "LPOC", e.poc_label_num);
}

/* Called by the final INSN scan whenever we see a var location.  We
   use it to drop labels in the right places, and throw the location in
   our lookup table.  */

static void
dwarf2out_var_location (rtx loc_note)
{
  char loclabel[MAX_ARTIFICIAL_LABEL_BYTES + 2];
  struct var_loc_node *newloc;
  rtx next_real;
  static const char *last_label;
  static const char *last_postcall_label;
  static bool last_in_cold_section_p;
  tree decl;

  if (!DECL_P (NOTE_VAR_LOCATION_DECL (loc_note)))
    return;

  next_real = next_real_insn (loc_note);
  /* If there are no instructions which would be affected by this note,
     don't do anything.  */
  if (next_real == NULL_RTX && !NOTE_DURING_CALL_P (loc_note))
    return;

  /* If there were any real insns between note we processed last time
     and this note (or if it is the first note), clear
     last_{,postcall_}label so that they are not reused this time.  */
  if (last_var_location_insn == NULL_RTX
      || last_var_location_insn != next_real
      || last_in_cold_section_p != in_cold_section_p)
    {
      last_label = NULL;
      last_postcall_label = NULL;
    }

  decl = NOTE_VAR_LOCATION_DECL (loc_note);
  newloc = add_var_loc_to_decl (decl, loc_note,
                                NOTE_DURING_CALL_P (loc_note)
                                ? last_postcall_label : last_label);
  if (newloc == NULL)
    return;

  /* If there were no real insns between note we processed last time
     and this note, use the label we emitted last time.  Otherwise
     create a new label and emit it.  */
  if (last_label == NULL)
    {
      ASM_GENERATE_INTERNAL_LABEL (loclabel, "LVL", loclabel_num);
      ASM_OUTPUT_DEBUG_LABEL (asm_out_file, "LVL", loclabel_num);
      loclabel_num++;
      last_label = ggc_strdup (loclabel);
    }

  if (!NOTE_DURING_CALL_P (loc_note))
    newloc->label = last_label;
  else
    {
      if (!last_postcall_label)
        {
          sprintf (loclabel, "%s-1", last_label);
          last_postcall_label = ggc_strdup (loclabel);
        }
      newloc->label = last_postcall_label;
    }

  last_var_location_insn = next_real;
  last_in_cold_section_p = in_cold_section_p;
}

/* We need to reset the locations at the beginning of each
   function. We can't do this in the end_function hook, because the
   declarations that use the locations won't have been output when
   that hook is called.  Also compute have_multiple_function_sections here.  */

static void
dwarf2out_begin_function (tree fun)
{
  if (function_section (fun) != text_section)
    have_multiple_function_sections = true;
  else if (flag_reorder_blocks_and_partition && !cold_text_section)
    {
      gcc_assert (current_function_decl == fun);
      cold_text_section = unlikely_text_section ();
      switch_to_section (cold_text_section);
      ASM_OUTPUT_LABEL (asm_out_file, cold_text_section_label);
      switch_to_section (current_function_section ());
    }

  dwarf2out_note_section_used ();
}

/* Output a label to mark the beginning of a source code line entry
   and record information relating to this source line, in
   'line_info_table' for later output of the .debug_line section.  */

static void
dwarf2out_source_line (unsigned int line, const char *filename,
                       int discriminator, bool is_stmt)
{
  static bool last_is_stmt = true;

  if (debug_info_level >= DINFO_LEVEL_NORMAL
      && line != 0)
    {
      int file_num = maybe_emit_file (lookup_filename (filename));

      switch_to_section (current_function_section ());

      /* If requested, emit something human-readable.  */
      if (flag_debug_asm)
        fprintf (asm_out_file, "\t%s %s:%d\n", ASM_COMMENT_START,
                 filename, line);

      if (DWARF2_ASM_LINE_DEBUG_INFO)
        {
          /* Emit the .loc directive understood by GNU as.  */
          fprintf (asm_out_file, "\t.loc %d %d 0", file_num, line);
          if (is_stmt != last_is_stmt)
            {
              fprintf (asm_out_file, " is_stmt %d", is_stmt ? 1 : 0);
              last_is_stmt = is_stmt;
            }
          if (SUPPORTS_DISCRIMINATOR && discriminator != 0)
            fprintf (asm_out_file, " discriminator %d", discriminator);
          fputc ('\n', asm_out_file);

          /* Indicate that line number info exists.  */
          line_info_table_in_use++;
        }
      else if (function_section (current_function_decl) != text_section)
        {
          dw_separate_line_info_ref line_info;
          targetm.asm_out.internal_label (asm_out_file,
                                          SEPARATE_LINE_CODE_LABEL,
                                          separate_line_info_table_in_use);

          /* Expand the line info table if necessary.  */
          if (separate_line_info_table_in_use
              == separate_line_info_table_allocated)
            {
              separate_line_info_table_allocated += LINE_INFO_TABLE_INCREMENT;
              separate_line_info_table
                = GGC_RESIZEVEC (dw_separate_line_info_entry,
                                 separate_line_info_table,
                                 separate_line_info_table_allocated);
              memset (separate_line_info_table
                       + separate_line_info_table_in_use,
                      0,
                      (LINE_INFO_TABLE_INCREMENT
                       * sizeof (dw_separate_line_info_entry)));
            }

          /* Add the new entry at the end of the line_info_table.  */
          line_info
            = &separate_line_info_table[separate_line_info_table_in_use++];
          line_info->dw_file_num = file_num;
          line_info->dw_line_num = line;
          line_info->function = current_function_funcdef_no;
        }
      else
        {
          dw_line_info_ref line_info;

          targetm.asm_out.internal_label (asm_out_file, LINE_CODE_LABEL,
                                     line_info_table_in_use);

          /* Expand the line info table if necessary.  */
          if (line_info_table_in_use == line_info_table_allocated)
            {
              line_info_table_allocated += LINE_INFO_TABLE_INCREMENT;
              line_info_table
                = GGC_RESIZEVEC (dw_line_info_entry, line_info_table,
                                 line_info_table_allocated);
              memset (line_info_table + line_info_table_in_use, 0,
                      LINE_INFO_TABLE_INCREMENT * sizeof (dw_line_info_entry));
            }

          /* Add the new entry at the end of the line_info_table.  */
          line_info = &line_info_table[line_info_table_in_use++];
          line_info->dw_file_num = file_num;
          line_info->dw_line_num = line;
        }
    }
}

/* Record the beginning of a new source file.  */

static void
dwarf2out_start_source_file (unsigned int lineno, const char *filename)
{
  if (flag_eliminate_dwarf2_dups && dwarf_version < 4)
    {
      /* Record the beginning of the file for break_out_includes.  */
      dw_die_ref bincl_die;

      bincl_die = new_die (DW_TAG_GNU_BINCL, comp_unit_die (), NULL);
      add_AT_string (bincl_die, DW_AT_name, remap_debug_filename (filename));
    }

  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    {
      macinfo_entry e;
      e.code = DW_MACINFO_start_file;
      e.lineno = lineno;
      e.info = xstrdup (filename);
      VEC_safe_push (macinfo_entry, gc, macinfo_table, &e);
    }
}

/* Record the end of a source file.  */

static void
dwarf2out_end_source_file (unsigned int lineno ATTRIBUTE_UNUSED)
{
  if (flag_eliminate_dwarf2_dups && dwarf_version < 4)
    /* Record the end of the file for break_out_includes.  */
    new_die (DW_TAG_GNU_EINCL, comp_unit_die (), NULL);

  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    {
      macinfo_entry e;
      e.code = DW_MACINFO_end_file;
      e.lineno = lineno;
      e.info = NULL;
      VEC_safe_push (macinfo_entry, gc, macinfo_table, &e);
    }
}

/* Called from debug_define in toplev.c.  The `buffer' parameter contains
   the tail part of the directive line, i.e. the part which is past the
   initial whitespace, #, whitespace, directive-name, whitespace part.  */

static void
dwarf2out_define (unsigned int lineno ATTRIBUTE_UNUSED,
                  const char *buffer ATTRIBUTE_UNUSED)
{
  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    {
      macinfo_entry e;
      e.code = DW_MACINFO_define;
      e.lineno = lineno;
      e.info = xstrdup (buffer);;
      VEC_safe_push (macinfo_entry, gc, macinfo_table, &e);
    }
}

/* Called from debug_undef in toplev.c.  The `buffer' parameter contains
   the tail part of the directive line, i.e. the part which is past the
   initial whitespace, #, whitespace, directive-name, whitespace part.  */

static void
dwarf2out_undef (unsigned int lineno ATTRIBUTE_UNUSED,
                 const char *buffer ATTRIBUTE_UNUSED)
{
  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    {
      macinfo_entry e;
      e.code = DW_MACINFO_undef;
      e.lineno = lineno;
      e.info = xstrdup (buffer);;
      VEC_safe_push (macinfo_entry, gc, macinfo_table, &e);
    }
}

static void
output_macinfo (void)
{
  unsigned i;
  unsigned long length = VEC_length (macinfo_entry, macinfo_table);
  macinfo_entry *ref;

  if (! length)
    return;

  for (i = 0; VEC_iterate (macinfo_entry, macinfo_table, i, ref); i++)
    {
      switch (ref->code)
        {
          case DW_MACINFO_start_file:
            {
              int file_num = maybe_emit_file (lookup_filename (ref->info));
              dw2_asm_output_data (1, DW_MACINFO_start_file, "Start new file");
              dw2_asm_output_data_uleb128 
                        (ref->lineno, "Included from line number %lu", 
                                                (unsigned long)ref->lineno);
              dw2_asm_output_data_uleb128 (file_num, "file %s", ref->info);
            }
            break;
          case DW_MACINFO_end_file:
            dw2_asm_output_data (1, DW_MACINFO_end_file, "End file");
            break;
          case DW_MACINFO_define:
            dw2_asm_output_data (1, DW_MACINFO_define, "Define macro");
            dw2_asm_output_data_uleb128 (ref->lineno, "At line number %lu", 
                                                (unsigned long)ref->lineno);
            dw2_asm_output_nstring (ref->info, -1, "The macro");
            break;
          case DW_MACINFO_undef:
            dw2_asm_output_data (1, DW_MACINFO_undef, "Undefine macro");
            dw2_asm_output_data_uleb128 (ref->lineno, "At line number %lu",
                                                (unsigned long)ref->lineno);
            dw2_asm_output_nstring (ref->info, -1, "The macro");
            break;
          default:
           fprintf (asm_out_file, "%s unrecognized macinfo code %lu\n",
             ASM_COMMENT_START, (unsigned long)ref->code);
          break;
        }
    }
}

/* Set up for Dwarf output at the start of compilation.  */

static void
dwarf2out_init (const char *filename ATTRIBUTE_UNUSED)
{
  /* Allocate the file_table.  */
  file_table = htab_create_ggc (50, file_table_hash,
                                file_table_eq, NULL);

  /* Allocate the decl_die_table.  */
  decl_die_table = htab_create_ggc (10, decl_die_table_hash,
                                    decl_die_table_eq, NULL);

  /* Allocate the decl_loc_table.  */
  decl_loc_table = htab_create_ggc (10, decl_loc_table_hash,
                                    decl_loc_table_eq, NULL);

  /* Allocate the initial hunk of the decl_scope_table.  */
  decl_scope_table = VEC_alloc (tree, gc, 256);

  /* Allocate the initial hunk of the abbrev_die_table.  */
  abbrev_die_table = ggc_alloc_cleared_vec_dw_die_ref
    (ABBREV_DIE_TABLE_INCREMENT);
  abbrev_die_table_allocated = ABBREV_DIE_TABLE_INCREMENT;
  /* Zero-th entry is allocated, but unused.  */
  abbrev_die_table_in_use = 1;

  /* Allocate the initial hunk of the line_info_table.  */
  line_info_table = ggc_alloc_cleared_vec_dw_line_info_entry
    (LINE_INFO_TABLE_INCREMENT);
  line_info_table_allocated = LINE_INFO_TABLE_INCREMENT;

  /* Zero-th entry is allocated, but unused.  */
  line_info_table_in_use = 1;

  /* Allocate the pubtypes and pubnames vectors.  */
  pubname_table = VEC_alloc (pubname_entry, gc, 32);
  pubtype_table = VEC_alloc (pubname_entry, gc, 32);

  /* Allocate the table that maps insn UIDs to vtable slot indexes.  */
  vcall_insn_table = htab_create_ggc (10, vcall_insn_table_hash,
                                      vcall_insn_table_eq, NULL);

  incomplete_types = VEC_alloc (tree, gc, 64);

  used_rtx_array = VEC_alloc (rtx, gc, 32);

  debug_info_section = get_section (DEBUG_INFO_SECTION,
                                    SECTION_DEBUG, NULL);
  debug_abbrev_section = get_section (DEBUG_ABBREV_SECTION,
                                      SECTION_DEBUG, NULL);
  debug_aranges_section = get_section (DEBUG_ARANGES_SECTION,
                                       SECTION_DEBUG, NULL);
  debug_macinfo_section = get_section (DEBUG_MACINFO_SECTION,
                                       SECTION_DEBUG, NULL);
  debug_line_section = get_section (DEBUG_LINE_SECTION,
                                    SECTION_DEBUG, NULL);
  debug_loc_section = get_section (DEBUG_LOC_SECTION,
                                   SECTION_DEBUG, NULL);
  debug_pubnames_section = get_section (DEBUG_PUBNAMES_SECTION,
                                        SECTION_DEBUG, NULL);
  debug_pubtypes_section = get_section (DEBUG_PUBTYPES_SECTION,
                                        SECTION_DEBUG, NULL);
  debug_dcall_section = get_section (DEBUG_DCALL_SECTION,
                                     SECTION_DEBUG, NULL);
  debug_vcall_section = get_section (DEBUG_VCALL_SECTION,
                                     SECTION_DEBUG, NULL);
  debug_str_section = get_section (DEBUG_STR_SECTION,
                                   DEBUG_STR_SECTION_FLAGS, NULL);
  debug_ranges_section = get_section (DEBUG_RANGES_SECTION,
                                      SECTION_DEBUG, NULL);
  debug_frame_section = get_section (DEBUG_FRAME_SECTION,
                                     SECTION_DEBUG, NULL);

  ASM_GENERATE_INTERNAL_LABEL (text_end_label, TEXT_END_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (abbrev_section_label,
                               DEBUG_ABBREV_SECTION_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (text_section_label, TEXT_SECTION_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (cold_text_section_label,
                               COLD_TEXT_SECTION_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (cold_end_label, COLD_END_LABEL, 0);

  ASM_GENERATE_INTERNAL_LABEL (debug_info_section_label,
                               DEBUG_INFO_SECTION_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (debug_line_section_label,
                               DEBUG_LINE_SECTION_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (ranges_section_label,
                               DEBUG_RANGES_SECTION_LABEL, 0);
  ASM_GENERATE_INTERNAL_LABEL (macinfo_section_label,
                               DEBUG_MACINFO_SECTION_LABEL, 0);

  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    macinfo_table = VEC_alloc (macinfo_entry, gc, 64);

  switch_to_section (text_section);
  ASM_OUTPUT_LABEL (asm_out_file, text_section_label);
}

/* Called before cgraph_optimize starts outputtting functions, variables
   and toplevel asms into assembly.  */

static void
dwarf2out_assembly_start (void)
{
  if (HAVE_GAS_CFI_SECTIONS_DIRECTIVE
      && dwarf2out_do_cfi_asm ()
      && (!(flag_unwind_tables || flag_exceptions)
          || targetm.except_unwind_info (&global_options) != UI_DWARF2))
    fprintf (asm_out_file, "\t.cfi_sections\t.debug_frame\n");
}

/* A helper function for dwarf2out_finish called through
   htab_traverse.  Emit one queued .debug_str string.  */

static int
output_indirect_string (void **h, void *v ATTRIBUTE_UNUSED)
{
  struct indirect_string_node *node = (struct indirect_string_node *) *h;

  if (node->label && node->refcount)
    {
      switch_to_section (debug_str_section);
      ASM_OUTPUT_LABEL (asm_out_file, node->label);
      assemble_string (node->str, strlen (node->str) + 1);
    }

  return 1;
}

#if ENABLE_ASSERT_CHECKING
/* Verify that all marks are clear.  */

static void
verify_marks_clear (dw_die_ref die)
{
  dw_die_ref c;

  gcc_assert (! die->die_mark);
  FOR_EACH_CHILD (die, c, verify_marks_clear (c));
}
#endif /* ENABLE_ASSERT_CHECKING */

/* Clear the marks for a die and its children.
   Be cool if the mark isn't set.  */

static void
prune_unmark_dies (dw_die_ref die)
{
  dw_die_ref c;

  if (die->die_mark)
    die->die_mark = 0;
  FOR_EACH_CHILD (die, c, prune_unmark_dies (c));
}

/* Given DIE that we're marking as used, find any other dies
   it references as attributes and mark them as used.  */

static void
prune_unused_types_walk_attribs (dw_die_ref die)
{
  dw_attr_ref a;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    {
      if (a->dw_attr_val.val_class == dw_val_class_die_ref)
        {
          /* A reference to another DIE.
             Make sure that it will get emitted.
             If it was broken out into a comdat group, don't follow it.  */
          if (dwarf_version < 4
              || a->dw_attr == DW_AT_specification
              || a->dw_attr_val.v.val_die_ref.die->die_id.die_type_node == NULL)
            prune_unused_types_mark (a->dw_attr_val.v.val_die_ref.die, 1);
        }
      /* Set the string's refcount to 0 so that prune_unused_types_mark
         accounts properly for it.  */
      if (AT_class (a) == dw_val_class_str)
        a->dw_attr_val.v.val_str->refcount = 0;
    }
}


/* Mark DIE as being used.  If DOKIDS is true, then walk down
   to DIE's children.  */

static void
prune_unused_types_mark (dw_die_ref die, int dokids)
{
  dw_die_ref c;

  if (die->die_mark == 0)
    {
      /* We haven't done this node yet.  Mark it as used.  */
      die->die_mark = 1;

      /* We also have to mark its parents as used.
         (But we don't want to mark our parents' kids due to this.)  */
      if (die->die_parent)
        prune_unused_types_mark (die->die_parent, 0);

      /* Mark any referenced nodes.  */
      prune_unused_types_walk_attribs (die);

      /* If this node is a specification,
         also mark the definition, if it exists.  */
      if (get_AT_flag (die, DW_AT_declaration) && die->die_definition)
        prune_unused_types_mark (die->die_definition, 1);
    }

  if (dokids && die->die_mark != 2)
    {
      /* We need to walk the children, but haven't done so yet.
         Remember that we've walked the kids.  */
      die->die_mark = 2;

      /* If this is an array type, we need to make sure our
         kids get marked, even if they're types.  If we're
         breaking out types into comdat sections, do this
         for all type definitions.  */
      if (die->die_tag == DW_TAG_array_type
          || (dwarf_version >= 4
              && is_type_die (die) && ! is_declaration_die (die)))
        FOR_EACH_CHILD (die, c, prune_unused_types_mark (c, 1));
      else
        FOR_EACH_CHILD (die, c, prune_unused_types_walk (c));
    }
}

/* For local classes, look if any static member functions were emitted
   and if so, mark them.  */

static void
prune_unused_types_walk_local_classes (dw_die_ref die)
{
  dw_die_ref c;

  if (die->die_mark == 2)
    return;

  switch (die->die_tag)
    {
    case DW_TAG_structure_type:
    case DW_TAG_union_type:
    case DW_TAG_class_type:
      break;

    case DW_TAG_subprogram:
      if (!get_AT_flag (die, DW_AT_declaration)
          || die->die_definition != NULL)
        prune_unused_types_mark (die, 1);
      return;

    default:
      return;
    }

  /* Mark children.  */
  FOR_EACH_CHILD (die, c, prune_unused_types_walk_local_classes (c));
}

/* Walk the tree DIE and mark types that we actually use.  */

static void
prune_unused_types_walk (dw_die_ref die)
{
  dw_die_ref c;

  /* Don't do anything if this node is already marked and
     children have been marked as well.  */
  if (die->die_mark == 2)
    return;

  switch (die->die_tag)
    {
    case DW_TAG_structure_type:
    case DW_TAG_union_type:
    case DW_TAG_class_type:
      if (die->die_perennial_p)
        break;

      for (c = die->die_parent; c; c = c->die_parent)
        if (c->die_tag == DW_TAG_subprogram)
          break;

      /* Finding used static member functions inside of classes
         is needed just for local classes, because for other classes
         static member function DIEs with DW_AT_specification
         are emitted outside of the DW_TAG_*_type.  If we ever change
         it, we'd need to call this even for non-local classes.  */
      if (c)
        prune_unused_types_walk_local_classes (die);

      /* It's a type node --- don't mark it.  */
      return;

    case DW_TAG_const_type:
    case DW_TAG_packed_type:
    case DW_TAG_pointer_type:
    case DW_TAG_reference_type:
    case DW_TAG_rvalue_reference_type:
    case DW_TAG_volatile_type:
    case DW_TAG_typedef:
    case DW_TAG_array_type:
    case DW_TAG_interface_type:
    case DW_TAG_friend:
    case DW_TAG_variant_part:
    case DW_TAG_enumeration_type:
    case DW_TAG_subroutine_type:
    case DW_TAG_string_type:
    case DW_TAG_set_type:
    case DW_TAG_subrange_type:
    case DW_TAG_ptr_to_member_type:
    case DW_TAG_file_type:
      if (die->die_perennial_p)
        break;

      /* It's a type node --- don't mark it.  */
      return;

    default:
      /* Mark everything else.  */
      break;
  }

  if (die->die_mark == 0)
    {
      die->die_mark = 1;

      /* Now, mark any dies referenced from here.  */
      prune_unused_types_walk_attribs (die);
    }

  die->die_mark = 2;

  /* Mark children.  */
  FOR_EACH_CHILD (die, c, prune_unused_types_walk (c));
}

/* Increment the string counts on strings referred to from DIE's
   attributes.  */

static void
prune_unused_types_update_strings (dw_die_ref die)
{
  dw_attr_ref a;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (AT_class (a) == dw_val_class_str)
      {
        struct indirect_string_node *s = a->dw_attr_val.v.val_str;
        s->refcount++;
        /* Avoid unnecessarily putting strings that are used less than
           twice in the hash table.  */
        if (s->refcount
            == ((DEBUG_STR_SECTION_FLAGS & SECTION_MERGE) ? 1 : 2))
          {
            void ** slot;
            slot = htab_find_slot_with_hash (debug_str_hash, s->str,
                                             htab_hash_string (s->str),
                                             INSERT);
            gcc_assert (*slot == NULL);
            *slot = s;
          }
      }
}

/* Remove from the tree DIE any dies that aren't marked.  */

static void
prune_unused_types_prune (dw_die_ref die)
{
  dw_die_ref c;

  gcc_assert (die->die_mark);
  prune_unused_types_update_strings (die);

  if (! die->die_child)
    return;

  c = die->die_child;
  do {
    dw_die_ref prev = c;
    for (c = c->die_sib; ! c->die_mark; c = c->die_sib)
      if (c == die->die_child)
        {
          /* No marked children between 'prev' and the end of the list.  */
          if (prev == c)
            /* No marked children at all.  */
            die->die_child = NULL;
          else
            {
              prev->die_sib = c->die_sib;
              die->die_child = prev;
            }
          return;
        }

    if (c != prev->die_sib)
      prev->die_sib = c;
    prune_unused_types_prune (c);
  } while (c != die->die_child);
}

/* A helper function for dwarf2out_finish called through
   htab_traverse.  Clear .debug_str strings that we haven't already
   decided to emit.  */

static int
prune_indirect_string (void **h, void *v ATTRIBUTE_UNUSED)
{
  struct indirect_string_node *node = (struct indirect_string_node *) *h;

  if (!node->label || !node->refcount)
    htab_clear_slot (debug_str_hash, h);

  return 1;
}

/* Remove dies representing declarations that we never use.  */

static void
prune_unused_types (void)
{
  unsigned int i;
  limbo_die_node *node;
  comdat_type_node *ctnode;
  pubname_ref pub;
  dcall_entry *dcall;

#if ENABLE_ASSERT_CHECKING
  /* All the marks should already be clear.  */
  verify_marks_clear (comp_unit_die ());
  for (node = limbo_die_list; node; node = node->next)
    verify_marks_clear (node->die);
  for (ctnode = comdat_type_list; ctnode; ctnode = ctnode->next)
    verify_marks_clear (ctnode->root_die);
#endif /* ENABLE_ASSERT_CHECKING */

  /* Mark types that are used in global variables.  */
  premark_types_used_by_global_vars ();

  /* Set the mark on nodes that are actually used.  */
  prune_unused_types_walk (comp_unit_die ());
  for (node = limbo_die_list; node; node = node->next)
    prune_unused_types_walk (node->die);
  for (ctnode = comdat_type_list; ctnode; ctnode = ctnode->next)
    {
      prune_unused_types_walk (ctnode->root_die);
      prune_unused_types_mark (ctnode->type_die, 1);
    }

  /* Also set the mark on nodes referenced from the
     pubname_table or arange_table.  */
  FOR_EACH_VEC_ELT (pubname_entry, pubname_table, i, pub)
    prune_unused_types_mark (pub->die, 1);
  for (i = 0; i < arange_table_in_use; i++)
    prune_unused_types_mark (arange_table[i], 1);

  /* Mark nodes referenced from the direct call table.  */
  FOR_EACH_VEC_ELT (dcall_entry, dcall_table, i, dcall)
    prune_unused_types_mark (dcall->targ_die, 1);

  /* Get rid of nodes that aren't marked; and update the string counts.  */
  if (debug_str_hash && debug_str_hash_forced)
    htab_traverse (debug_str_hash, prune_indirect_string, NULL);
  else if (debug_str_hash)
    htab_empty (debug_str_hash);
  prune_unused_types_prune (comp_unit_die ());
  for (node = limbo_die_list; node; node = node->next)
    prune_unused_types_prune (node->die);
  for (ctnode = comdat_type_list; ctnode; ctnode = ctnode->next)
    prune_unused_types_prune (ctnode->root_die);

  /* Leave the marks clear.  */
  prune_unmark_dies (comp_unit_die ());
  for (node = limbo_die_list; node; node = node->next)
    prune_unmark_dies (node->die);
  for (ctnode = comdat_type_list; ctnode; ctnode = ctnode->next)
    prune_unmark_dies (ctnode->root_die);
}

/* Set the parameter to true if there are any relative pathnames in
   the file table.  */
static int
file_table_relative_p (void ** slot, void *param)
{
  bool *p = (bool *) param;
  struct dwarf_file_data *d = (struct dwarf_file_data *) *slot;
  if (!IS_ABSOLUTE_PATH (d->filename))
    {
      *p = true;
      return 0;
    }
  return 1;
}

/* Routines to manipulate hash table of comdat type units.  */

static hashval_t
htab_ct_hash (const void *of)
{
  hashval_t h;
  const comdat_type_node *const type_node = (const comdat_type_node *) of;

  memcpy (&h, type_node->signature, sizeof (h));
  return h;
}

static int
htab_ct_eq (const void *of1, const void *of2)
{
  const comdat_type_node *const type_node_1 = (const comdat_type_node *) of1;
  const comdat_type_node *const type_node_2 = (const comdat_type_node *) of2;

  return (! memcmp (type_node_1->signature, type_node_2->signature,
                    DWARF_TYPE_SIGNATURE_SIZE));
}

/* Move a DW_AT_{,MIPS_}linkage_name attribute just added to dw_die_ref
   to the location it would have been added, should we know its
   DECL_ASSEMBLER_NAME when we added other attributes.  This will
   probably improve compactness of debug info, removing equivalent
   abbrevs, and hide any differences caused by deferring the
   computation of the assembler name, triggered by e.g. PCH.  */

static inline void
move_linkage_attr (dw_die_ref die)
{
  unsigned ix = VEC_length (dw_attr_node, die->die_attr);
  dw_attr_node linkage = *VEC_index (dw_attr_node, die->die_attr, ix - 1);

  gcc_assert (linkage.dw_attr == DW_AT_linkage_name
              || linkage.dw_attr == DW_AT_MIPS_linkage_name);

  while (--ix > 0)
    {
      dw_attr_node *prev = VEC_index (dw_attr_node, die->die_attr, ix - 1);

      if (prev->dw_attr == DW_AT_decl_line || prev->dw_attr == DW_AT_name)
        break;
    }

  if (ix != VEC_length (dw_attr_node, die->die_attr) - 1)
    {
      VEC_pop (dw_attr_node, die->die_attr);
      VEC_quick_insert (dw_attr_node, die->die_attr, ix, &linkage);
    }
}

/* Helper function for resolve_addr, attempt to resolve
   one CONST_STRING, return non-zero if not successful.  Similarly verify that
   SYMBOL_REFs refer to variables emitted in the current CU.  */

static int
resolve_one_addr (rtx *addr, void *data ATTRIBUTE_UNUSED)
{
  rtx rtl = *addr;

  if (GET_CODE (rtl) == CONST_STRING)
    {
      size_t len = strlen (XSTR (rtl, 0)) + 1;
      tree t = build_string (len, XSTR (rtl, 0));
      tree tlen = build_int_cst (NULL_TREE, len - 1);
      TREE_TYPE (t)
        = build_array_type (char_type_node, build_index_type (tlen));
      rtl = lookup_constant_def (t);
      if (!rtl || !MEM_P (rtl))
        return 1;
      rtl = XEXP (rtl, 0);
      VEC_safe_push (rtx, gc, used_rtx_array, rtl);
      *addr = rtl;
      return 0;
    }

  if (GET_CODE (rtl) == SYMBOL_REF
      && SYMBOL_REF_DECL (rtl)
      && !TREE_ASM_WRITTEN (SYMBOL_REF_DECL (rtl)))
    return 1;

  if (GET_CODE (rtl) == CONST
      && for_each_rtx (&XEXP (rtl, 0), resolve_one_addr, NULL))
    return 1;

  return 0;
}

/* Helper function for resolve_addr, handle one location
   expression, return false if at least one CONST_STRING or SYMBOL_REF in
   the location list couldn't be resolved.  */

static bool
resolve_addr_in_expr (dw_loc_descr_ref loc)
{
  for (; loc; loc = loc->dw_loc_next)
    if (((loc->dw_loc_opc == DW_OP_addr || loc->dtprel)
         && resolve_one_addr (&loc->dw_loc_oprnd1.v.val_addr, NULL))
        || (loc->dw_loc_opc == DW_OP_implicit_value
            && loc->dw_loc_oprnd2.val_class == dw_val_class_addr
            && resolve_one_addr (&loc->dw_loc_oprnd2.v.val_addr, NULL)))
      return false;
    else if (loc->dw_loc_opc == DW_OP_GNU_implicit_pointer
             && loc->dw_loc_oprnd1.val_class == dw_val_class_decl_ref)
      {
        dw_die_ref ref
          = lookup_decl_die (loc->dw_loc_oprnd1.v.val_decl_ref);
        if (ref == NULL)
          return false;
        loc->dw_loc_oprnd1.val_class = dw_val_class_die_ref;
        loc->dw_loc_oprnd1.v.val_die_ref.die = ref;
        loc->dw_loc_oprnd1.v.val_die_ref.external = 0;
      }
  return true;
}

/* Resolve DW_OP_addr and DW_AT_const_value CONST_STRING arguments to
   an address in .rodata section if the string literal is emitted there,
   or remove the containing location list or replace DW_AT_const_value
   with DW_AT_location and empty location expression, if it isn't found
   in .rodata.  Similarly for SYMBOL_REFs, keep only those that refer
   to something that has been emitted in the current CU.  */

static void
resolve_addr (dw_die_ref die)
{
  dw_die_ref c;
  dw_attr_ref a;
  dw_loc_list_ref *curr;
  unsigned ix;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    switch (AT_class (a))
      {
      case dw_val_class_loc_list:
        curr = AT_loc_list_ptr (a);
        while (*curr)
          {
            if (!resolve_addr_in_expr ((*curr)->expr))
              {
                dw_loc_list_ref next = (*curr)->dw_loc_next;
                if (next && (*curr)->ll_symbol)
                  {
                    gcc_assert (!next->ll_symbol);
                    next->ll_symbol = (*curr)->ll_symbol;
                  }
                *curr = next;
              }
            else
              curr = &(*curr)->dw_loc_next;
          }
        if (!AT_loc_list (a))
          {
            remove_AT (die, a->dw_attr);
            ix--;
          }
        break;
      case dw_val_class_loc:
        if (!resolve_addr_in_expr (AT_loc (a)))
          {
            remove_AT (die, a->dw_attr);
            ix--;
          }
        break;
      case dw_val_class_addr:
        if (a->dw_attr == DW_AT_const_value
            && resolve_one_addr (&a->dw_attr_val.v.val_addr, NULL))
          {
            remove_AT (die, a->dw_attr);
            ix--;
          }
        break;
      default:
        break;
      }

  FOR_EACH_CHILD (die, c, resolve_addr (c));
}
\f
/* Helper routines for optimize_location_lists.
   This pass tries to share identical local lists in .debug_loc
   section.  */

/* Iteratively hash operands of LOC opcode.  */

static inline hashval_t
hash_loc_operands (dw_loc_descr_ref loc, hashval_t hash)
{
  dw_val_ref val1 = &loc->dw_loc_oprnd1;
  dw_val_ref val2 = &loc->dw_loc_oprnd2;

  switch (loc->dw_loc_opc)
    {
    case DW_OP_const4u:
    case DW_OP_const8u:
      if (loc->dtprel)
        goto hash_addr;
      /* FALLTHRU */
    case DW_OP_const1u:
    case DW_OP_const1s:
    case DW_OP_const2u:
    case DW_OP_const2s:
    case DW_OP_const4s:
    case DW_OP_const8s:
    case DW_OP_constu:
    case DW_OP_consts:
    case DW_OP_pick:
    case DW_OP_plus_uconst:
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
    case DW_OP_regx:
    case DW_OP_fbreg:
    case DW_OP_piece:
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      hash = iterative_hash_object (val1->v.val_int, hash);
      break;
    case DW_OP_skip:
    case DW_OP_bra:
      {
        int offset;

        gcc_assert (val1->val_class == dw_val_class_loc);
        offset = val1->v.val_loc->dw_loc_addr - (loc->dw_loc_addr + 3);
        hash = iterative_hash_object (offset, hash);
      }
      break;
    case DW_OP_implicit_value:
      hash = iterative_hash_object (val1->v.val_unsigned, hash);
      switch (val2->val_class)
        {
        case dw_val_class_const:
          hash = iterative_hash_object (val2->v.val_int, hash);
          break;
        case dw_val_class_vec:
          {
            unsigned int elt_size = val2->v.val_vec.elt_size;
            unsigned int len = val2->v.val_vec.length;

            hash = iterative_hash_object (elt_size, hash);
            hash = iterative_hash_object (len, hash);
            hash = iterative_hash (val2->v.val_vec.array,
                                   len * elt_size, hash);
          }
          break;
        case dw_val_class_const_double:
          hash = iterative_hash_object (val2->v.val_double.low, hash);
          hash = iterative_hash_object (val2->v.val_double.high, hash);
          break;
        case dw_val_class_addr:
          hash = iterative_hash_rtx (val2->v.val_addr, hash);
          break;
        default:
          gcc_unreachable ();
        }
      break;
    case DW_OP_bregx:
    case DW_OP_bit_piece:
      hash = iterative_hash_object (val1->v.val_int, hash);
      hash = iterative_hash_object (val2->v.val_int, hash);
      break;
    case DW_OP_addr:
    hash_addr:
      if (loc->dtprel)
        {
          unsigned char dtprel = 0xd1;
          hash = iterative_hash_object (dtprel, hash);
        }
      hash = iterative_hash_rtx (val1->v.val_addr, hash);
      break;
    case DW_OP_GNU_implicit_pointer:
      hash = iterative_hash_object (val2->v.val_int, hash);
      break;

    default:
      /* Other codes have no operands.  */
      break;
    }
  return hash;
}

/* Iteratively hash the whole DWARF location expression LOC.  */

static inline hashval_t
hash_locs (dw_loc_descr_ref loc, hashval_t hash)
{
  dw_loc_descr_ref l;
  bool sizes_computed = false;
  /* Compute sizes, so that DW_OP_skip/DW_OP_bra can be checksummed.  */
  size_of_locs (loc);

  for (l = loc; l != NULL; l = l->dw_loc_next)
    {
      enum dwarf_location_atom opc = l->dw_loc_opc;
      hash = iterative_hash_object (opc, hash);
      if ((opc == DW_OP_skip || opc == DW_OP_bra) && !sizes_computed)
        {
          size_of_locs (loc);
          sizes_computed = true;
        }
      hash = hash_loc_operands (l, hash);
    }
  return hash;
}

/* Compute hash of the whole location list LIST_HEAD.  */

static inline void
hash_loc_list (dw_loc_list_ref list_head)
{
  dw_loc_list_ref curr = list_head;
  hashval_t hash = 0;

  for (curr = list_head; curr != NULL; curr = curr->dw_loc_next)
    {
      hash = iterative_hash (curr->begin, strlen (curr->begin) + 1, hash);
      hash = iterative_hash (curr->end, strlen (curr->end) + 1, hash);
      if (curr->section)
        hash = iterative_hash (curr->section, strlen (curr->section) + 1,
                               hash);
      hash = hash_locs (curr->expr, hash);
    }
  list_head->hash = hash;
}

/* Return true if X and Y opcodes have the same operands.  */

static inline bool
compare_loc_operands (dw_loc_descr_ref x, dw_loc_descr_ref y)
{
  dw_val_ref valx1 = &x->dw_loc_oprnd1;
  dw_val_ref valx2 = &x->dw_loc_oprnd2;
  dw_val_ref valy1 = &y->dw_loc_oprnd1;
  dw_val_ref valy2 = &y->dw_loc_oprnd2;

  switch (x->dw_loc_opc)
    {
    case DW_OP_const4u:
    case DW_OP_const8u:
      if (x->dtprel)
        goto hash_addr;
      /* FALLTHRU */
    case DW_OP_const1u:
    case DW_OP_const1s:
    case DW_OP_const2u:
    case DW_OP_const2s:
    case DW_OP_const4s:
    case DW_OP_const8s:
    case DW_OP_constu:
    case DW_OP_consts:
    case DW_OP_pick:
    case DW_OP_plus_uconst:
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
    case DW_OP_regx:
    case DW_OP_fbreg:
    case DW_OP_piece:
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      return valx1->v.val_int == valy1->v.val_int;
    case DW_OP_skip:
    case DW_OP_bra:
      gcc_assert (valx1->val_class == dw_val_class_loc
                  && valy1->val_class == dw_val_class_loc
                  && x->dw_loc_addr == y->dw_loc_addr);
      return valx1->v.val_loc->dw_loc_addr == valy1->v.val_loc->dw_loc_addr;
    case DW_OP_implicit_value:
      if (valx1->v.val_unsigned != valy1->v.val_unsigned
          || valx2->val_class != valy2->val_class)
        return false;
      switch (valx2->val_class)
        {
        case dw_val_class_const:
          return valx2->v.val_int == valy2->v.val_int;
        case dw_val_class_vec:
          return valx2->v.val_vec.elt_size == valy2->v.val_vec.elt_size
                 && valx2->v.val_vec.length == valy2->v.val_vec.length
                 && memcmp (valx2->v.val_vec.array, valy2->v.val_vec.array,
                            valx2->v.val_vec.elt_size
                            * valx2->v.val_vec.length) == 0;
        case dw_val_class_const_double:
          return valx2->v.val_double.low == valy2->v.val_double.low
                 && valx2->v.val_double.high == valy2->v.val_double.high;
        case dw_val_class_addr:
          return rtx_equal_p (valx2->v.val_addr, valy2->v.val_addr);
        default:
          gcc_unreachable ();
        }
    case DW_OP_bregx:
    case DW_OP_bit_piece:
      return valx1->v.val_int == valy1->v.val_int
             && valx2->v.val_int == valy2->v.val_int;
    case DW_OP_addr:
    hash_addr:
      return rtx_equal_p (valx1->v.val_addr, valx2->v.val_addr);
    case DW_OP_GNU_implicit_pointer:
      return valx1->val_class == dw_val_class_die_ref
             && valx1->val_class == valy1->val_class
             && valx1->v.val_die_ref.die == valy1->v.val_die_ref.die
             && valx2->v.val_int == valy2->v.val_int;
    default:
      /* Other codes have no operands.  */
      return true;
    }
}

/* Return true if DWARF location expressions X and Y are the same.  */

static inline bool
compare_locs (dw_loc_descr_ref x, dw_loc_descr_ref y)
{
  for (; x != NULL && y != NULL; x = x->dw_loc_next, y = y->dw_loc_next)
    if (x->dw_loc_opc != y->dw_loc_opc
        || x->dtprel != y->dtprel
        || !compare_loc_operands (x, y))
      break;
  return x == NULL && y == NULL;
}

/* Return precomputed hash of location list X.  */

static hashval_t
loc_list_hash (const void *x)
{
  return ((const struct dw_loc_list_struct *) x)->hash;
}

/* Return 1 if location lists X and Y are the same.  */

static int
loc_list_eq (const void *x, const void *y)
{
  const struct dw_loc_list_struct *a = (const struct dw_loc_list_struct *) x;
  const struct dw_loc_list_struct *b = (const struct dw_loc_list_struct *) y;
  if (a == b)
    return 1;
  if (a->hash != b->hash)
    return 0;
  for (; a != NULL && b != NULL; a = a->dw_loc_next, b = b->dw_loc_next)
    if (strcmp (a->begin, b->begin) != 0
        || strcmp (a->end, b->end) != 0
        || (a->section == NULL) != (b->section == NULL)
        || (a->section && strcmp (a->section, b->section) != 0)
        || !compare_locs (a->expr, b->expr))
      break;
  return a == NULL && b == NULL;
}

/* Recursively optimize location lists referenced from DIE
   children and share them whenever possible.  */

static void
optimize_location_lists_1 (dw_die_ref die, htab_t htab)
{
  dw_die_ref c;
  dw_attr_ref a;
  unsigned ix;
  void **slot;

  FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
    if (AT_class (a) == dw_val_class_loc_list)
      {
        dw_loc_list_ref list = AT_loc_list (a);
        /* TODO: perform some optimizations here, before hashing
           it and storing into the hash table.  */
        hash_loc_list (list);
        slot = htab_find_slot_with_hash (htab, list, list->hash,
                                         INSERT);
        if (*slot == NULL)
          *slot = (void *) list;
        else
          a->dw_attr_val.v.val_loc_list = (dw_loc_list_ref) *slot;
      }

  FOR_EACH_CHILD (die, c, optimize_location_lists_1 (c, htab));
}

/* Optimize location lists referenced from DIE
   children and share them whenever possible.  */

static void
optimize_location_lists (dw_die_ref die)
{
  htab_t htab = htab_create (500, loc_list_hash, loc_list_eq, NULL);
  optimize_location_lists_1 (die, htab);
  htab_delete (htab);
}
\f
/* Output stuff that dwarf requires at the end of every file,
   and generate the DWARF-2 debugging info.  */

static void
dwarf2out_finish (const char *filename)
{
  limbo_die_node *node, *next_node;
  comdat_type_node *ctnode;
  htab_t comdat_type_table;
  unsigned int i;

  gen_remaining_tmpl_value_param_die_attribute ();

  /* Add the name for the main input file now.  We delayed this from
     dwarf2out_init to avoid complications with PCH.  */
  add_name_attribute (comp_unit_die (), remap_debug_filename (filename));
  if (!IS_ABSOLUTE_PATH (filename))
    add_comp_dir_attribute (comp_unit_die ());
  else if (get_AT (comp_unit_die (), DW_AT_comp_dir) == NULL)
    {
      bool p = false;
      htab_traverse (file_table, file_table_relative_p, &p);
      if (p)
        add_comp_dir_attribute (comp_unit_die ());
    }

  for (i = 0; i < VEC_length (deferred_locations, deferred_locations_list); i++)
    {
      add_location_or_const_value_attribute (
        VEC_index (deferred_locations, deferred_locations_list, i)->die,
        VEC_index (deferred_locations, deferred_locations_list, i)->variable,
        DW_AT_location);
    }

  /* Traverse the limbo die list, and add parent/child links.  The only
     dies without parents that should be here are concrete instances of
     inline functions, and the comp_unit_die.  We can ignore the comp_unit_die.
     For concrete instances, we can get the parent die from the abstract
     instance.  */
  for (node = limbo_die_list; node; node = next_node)
    {
      dw_die_ref die = node->die;
      next_node = node->next;

      if (die->die_parent == NULL)
        {
          dw_die_ref origin = get_AT_ref (die, DW_AT_abstract_origin);

          if (origin)
            add_child_die (origin->die_parent, die);
          else if (is_cu_die (die))
            ;
          else if (seen_error ())
            /* It's OK to be confused by errors in the input.  */
            add_child_die (comp_unit_die (), die);
          else
            {
              /* In certain situations, the lexical block containing a
                 nested function can be optimized away, which results
                 in the nested function die being orphaned.  Likewise
                 with the return type of that nested function.  Force
                 this to be a child of the containing function.

                 It may happen that even the containing function got fully
                 inlined and optimized out.  In that case we are lost and
                 assign the empty child.  This should not be big issue as
                 the function is likely unreachable too.  */
              tree context = NULL_TREE;

              gcc_assert (node->created_for);

              if (DECL_P (node->created_for))
                context = DECL_CONTEXT (node->created_for);
              else if (TYPE_P (node->created_for))
                context = TYPE_CONTEXT (node->created_for);

              gcc_assert (context
                          && (TREE_CODE (context) == FUNCTION_DECL
                              || TREE_CODE (context) == NAMESPACE_DECL));

              origin = lookup_decl_die (context);
              if (origin)
                add_child_die (origin, die);
              else
                add_child_die (comp_unit_die (), die);
            }
        }
    }

  limbo_die_list = NULL;

  resolve_addr (comp_unit_die ());

  for (node = deferred_asm_name; node; node = node->next)
    {
      tree decl = node->created_for;
      if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl))
        {
          add_linkage_attr (node->die, decl);
          move_linkage_attr (node->die);
        }
    }

  deferred_asm_name = NULL;

  /* Walk through the list of incomplete types again, trying once more to
     emit full debugging info for them.  */
  retry_incomplete_types ();

  if (flag_eliminate_unused_debug_types)
    prune_unused_types ();

  /* Generate separate CUs for each of the include files we've seen.
     They will go into limbo_die_list.  */
  if (flag_eliminate_dwarf2_dups && dwarf_version < 4)
    break_out_includes (comp_unit_die ());

  /* Generate separate COMDAT sections for type DIEs. */
  if (dwarf_version >= 4)
    {
      break_out_comdat_types (comp_unit_die ());

      /* Each new type_unit DIE was added to the limbo die list when created.
         Since these have all been added to comdat_type_list, clear the
         limbo die list.  */
      limbo_die_list = NULL;

      /* For each new comdat type unit, copy declarations for incomplete
         types to make the new unit self-contained (i.e., no direct
         references to the main compile unit).  */
      for (ctnode = comdat_type_list; ctnode != NULL; ctnode = ctnode->next)
        copy_decls_for_unworthy_types (ctnode->root_die);
      copy_decls_for_unworthy_types (comp_unit_die ());

      /* In the process of copying declarations from one unit to another,
         we may have left some declarations behind that are no longer
         referenced.  Prune them.  */
      prune_unused_types ();
    }

  /* Traverse the DIE's and add add sibling attributes to those DIE's
     that have children.  */
  add_sibling_attributes (comp_unit_die ());
  for (node = limbo_die_list; node; node = node->next)
    add_sibling_attributes (node->die);
  for (ctnode = comdat_type_list; ctnode != NULL; ctnode = ctnode->next)
    add_sibling_attributes (ctnode->root_die);

  /* Output a terminator label for the .text section.  */
  switch_to_section (text_section);
  targetm.asm_out.internal_label (asm_out_file, TEXT_END_LABEL, 0);
  if (cold_text_section)
    {
      switch_to_section (cold_text_section);
      targetm.asm_out.internal_label (asm_out_file, COLD_END_LABEL, 0);
    }

  /* We can only use the low/high_pc attributes if all of the code was
     in .text.  */
  if (!have_multiple_function_sections 
      || (dwarf_version < 3 && dwarf_strict))
    {
      add_AT_lbl_id (comp_unit_die (), DW_AT_low_pc, text_section_label);
      add_AT_lbl_id (comp_unit_die (), DW_AT_high_pc, text_end_label);
    }

  else
    {
      unsigned fde_idx = 0;
      bool range_list_added = false;

      /* We need to give .debug_loc and .debug_ranges an appropriate
         "base address".  Use zero so that these addresses become
         absolute.  Historically, we've emitted the unexpected
         DW_AT_entry_pc instead of DW_AT_low_pc for this purpose.
         Emit both to give time for other tools to adapt.  */
      add_AT_addr (comp_unit_die (), DW_AT_low_pc, const0_rtx);
      add_AT_addr (comp_unit_die (), DW_AT_entry_pc, const0_rtx);

      if (text_section_used)
        add_ranges_by_labels (comp_unit_die (), text_section_label,
                              text_end_label, &range_list_added);
      if (flag_reorder_blocks_and_partition && cold_text_section_used)
        add_ranges_by_labels (comp_unit_die (), cold_text_section_label,
                              cold_end_label, &range_list_added);

      for (fde_idx = 0; fde_idx < fde_table_in_use; fde_idx++)
        {
          dw_fde_ref fde = &fde_table[fde_idx];

          if (fde->dw_fde_switched_sections)
            {
              if (!fde->in_std_section)
                add_ranges_by_labels (comp_unit_die (),
                                      fde->dw_fde_hot_section_label,
                                      fde->dw_fde_hot_section_end_label,
                                      &range_list_added);
              if (!fde->cold_in_std_section)
                add_ranges_by_labels (comp_unit_die (),
                                      fde->dw_fde_unlikely_section_label,
                                      fde->dw_fde_unlikely_section_end_label,
                                      &range_list_added);
            }
          else if (!fde->in_std_section)
            add_ranges_by_labels (comp_unit_die (), fde->dw_fde_begin,
                                  fde->dw_fde_end, &range_list_added);
        }

      if (range_list_added)
        add_ranges (NULL);
    }

  if (debug_info_level >= DINFO_LEVEL_NORMAL)
    add_AT_lineptr (comp_unit_die (), DW_AT_stmt_list,
                    debug_line_section_label);

  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    add_AT_macptr (comp_unit_die (), DW_AT_macro_info, macinfo_section_label);

  if (have_location_lists)
    optimize_location_lists (comp_unit_die ());

  /* Output all of the compilation units.  We put the main one last so that
     the offsets are available to output_pubnames.  */
  for (node = limbo_die_list; node; node = node->next)
    output_comp_unit (node->die, 0);

  comdat_type_table = htab_create (100, htab_ct_hash, htab_ct_eq, NULL);
  for (ctnode = comdat_type_list; ctnode != NULL; ctnode = ctnode->next)
    {
      void **slot = htab_find_slot (comdat_type_table, ctnode, INSERT);

      /* Don't output duplicate types.  */
      if (*slot != HTAB_EMPTY_ENTRY)
        continue;

      /* Add a pointer to the line table for the main compilation unit
         so that the debugger can make sense of DW_AT_decl_file
         attributes.  */
      if (debug_info_level >= DINFO_LEVEL_NORMAL)
        add_AT_lineptr (ctnode->root_die, DW_AT_stmt_list,
                        debug_line_section_label);

      output_comdat_type_unit (ctnode);
      *slot = ctnode;
    }
  htab_delete (comdat_type_table);

  /* Output the main compilation unit if non-empty or if .debug_macinfo
     will be emitted.  */
  output_comp_unit (comp_unit_die (), debug_info_level >= DINFO_LEVEL_VERBOSE);

  /* Output the abbreviation table.  */
  switch_to_section (debug_abbrev_section);
  ASM_OUTPUT_LABEL (asm_out_file, abbrev_section_label);
  output_abbrev_section ();

  /* Output location list section if necessary.  */
  if (have_location_lists)
    {
      /* Output the location lists info.  */
      switch_to_section (debug_loc_section);
      ASM_GENERATE_INTERNAL_LABEL (loc_section_label,
                                   DEBUG_LOC_SECTION_LABEL, 0);
      ASM_OUTPUT_LABEL (asm_out_file, loc_section_label);
      output_location_lists (comp_unit_die ());
    }

  /* Output public names table if necessary.  */
  if (!VEC_empty (pubname_entry, pubname_table))
    {
      gcc_assert (info_section_emitted);
      switch_to_section (debug_pubnames_section);
      output_pubnames (pubname_table);
    }

  /* Output public types table if necessary.  */
  /* ??? Only defined by DWARF3, but emitted by Darwin for DWARF2.
     It shouldn't hurt to emit it always, since pure DWARF2 consumers
     simply won't look for the section.  */
  if (!VEC_empty (pubname_entry, pubtype_table))
    {
      bool empty = false;
      
      if (flag_eliminate_unused_debug_types)
        {
          /* The pubtypes table might be emptied by pruning unused items.  */
          unsigned i;
          pubname_ref p;
          empty = true;
          FOR_EACH_VEC_ELT (pubname_entry, pubtype_table, i, p)
            if (p->die->die_offset != 0)
              {
                empty = false;
                break;
              }
        }
      if (!empty)
        {
          gcc_assert (info_section_emitted);
          switch_to_section (debug_pubtypes_section);
          output_pubnames (pubtype_table);
        }
    }

  /* Output direct and virtual call tables if necessary.  */
  if (!VEC_empty (dcall_entry, dcall_table))
    {
      switch_to_section (debug_dcall_section);
      output_dcall_table ();
    }
  if (!VEC_empty (vcall_entry, vcall_table))
    {
      switch_to_section (debug_vcall_section);
      output_vcall_table ();
    }

  /* Output the address range information.  We only put functions in the arange
     table, so don't write it out if we don't have any.  */
  if (arange_table_in_use)
    {
      switch_to_section (debug_aranges_section);
      output_aranges ();
    }

  /* Output ranges section if necessary.  */
  if (ranges_table_in_use)
    {
      switch_to_section (debug_ranges_section);
      ASM_OUTPUT_LABEL (asm_out_file, ranges_section_label);
      output_ranges ();
    }

  /* Output the source line correspondence table.  We must do this
     even if there is no line information.  Otherwise, on an empty
     translation unit, we will generate a present, but empty,
     .debug_info section.  IRIX 6.5 `nm' will then complain when
     examining the file.  This is done late so that any filenames
     used by the debug_info section are marked as 'used'.  */
  switch_to_section (debug_line_section);
  ASM_OUTPUT_LABEL (asm_out_file, debug_line_section_label);
  if (! DWARF2_ASM_LINE_DEBUG_INFO)
    output_line_info ();

  /* Have to end the macro section.  */
  if (debug_info_level >= DINFO_LEVEL_VERBOSE)
    {
      switch_to_section (debug_macinfo_section);
      ASM_OUTPUT_LABEL (asm_out_file, macinfo_section_label);
      if (!VEC_empty (macinfo_entry, macinfo_table))
        output_macinfo ();
      dw2_asm_output_data (1, 0, "End compilation unit");
    }

  /* If we emitted any DW_FORM_strp form attribute, output the string
     table too.  */
  if (debug_str_hash)
    htab_traverse (debug_str_hash, output_indirect_string, NULL);
}

#include "gt-dwarf2out.h"