Move *-*-gnu* pattern below *-*-linux*.

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

/* Output variables, constants and external declarations, for GNU compiler.
   Copyright (C) 1987, 88, 89, 92-98, 1999 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


/* This file handles generation of all the assembler code
   *except* the instructions of a function.
   This includes declarations of variables and their initial values.

   We also output the assembler code for constants stored in memory
   and are responsible for combining constants with the same value.  */

#include "config.h"
#include "system.h"
#include <setjmp.h>
/* #include <stab.h> */
#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "function.h"
#include "expr.h"
#include "output.h"
#include "hard-reg-set.h"
#include "regs.h"
#include "defaults.h"
#include "real.h"
#include "toplev.h"
#include "dbxout.h"
#include "sdbout.h"

#include "obstack.h"
#include "c-pragma.h"

#ifdef XCOFF_DEBUGGING_INFO
#include "xcoffout.h"
#endif

#ifndef TRAMPOLINE_ALIGNMENT
#define TRAMPOLINE_ALIGNMENT FUNCTION_BOUNDARY
#endif

#ifndef ASM_STABS_OP
#define ASM_STABS_OP ".stabs"
#endif

/* Define the prefix to use when check_memory_usage_flag is enable.  */
#ifdef NO_DOLLAR_IN_LABEL
#ifdef NO_DOT_IN_LABEL
#define CHKR_PREFIX "chkr_prefix_"
#else /* !NO_DOT_IN_LABEL */
#define CHKR_PREFIX "chkr."
#endif 
#else /* !NO_DOLLAR_IN_LABEL */
#define CHKR_PREFIX "chkr$"
#endif
#define CHKR_PREFIX_SIZE (sizeof (CHKR_PREFIX) - 1)

/* File in which assembler code is being written.  */

extern FILE *asm_out_file;

/* The (assembler) name of the first globally-visible object output.  */
char *first_global_object_name;
char *weak_global_object_name;

extern struct obstack *current_obstack;
extern struct obstack *saveable_obstack;
extern struct obstack *rtl_obstack;
extern struct obstack permanent_obstack;
#define obstack_chunk_alloc xmalloc

/* Number for making the label on the next
   constant that is stored in memory.  */

int const_labelno;

/* Number for making the label on the next
   static variable internal to a function.  */

int var_labelno;

/* Carry information from ASM_DECLARE_OBJECT_NAME
   to ASM_FINISH_DECLARE_OBJECT.  */

int size_directive_output;

/* The last decl for which assemble_variable was called,
   if it did ASM_DECLARE_OBJECT_NAME.
   If the last call to assemble_variable didn't do that,
   this holds 0.  */

tree last_assemble_variable_decl;

/* Nonzero if at least one function definition has been seen.  */

static int function_defined;

struct addr_const;
struct constant_descriptor;
struct rtx_const;
struct pool_constant;

static const char *strip_reg_name       PROTO((const char *));
static int contains_pointers_p          PROTO((tree));
static void decode_addr_const           PROTO((tree, struct addr_const *));
static int const_hash                   PROTO((tree));
static int compare_constant             PROTO((tree,
                                               struct constant_descriptor *));
static char *compare_constant_1         PROTO((tree, char *));
static struct constant_descriptor *record_constant PROTO((tree));
static void record_constant_1           PROTO((tree));
static tree copy_constant               PROTO((tree));
static void output_constant_def_contents  PROTO((tree, int, int));
static void decode_rtx_const            PROTO((enum machine_mode, rtx,
                                               struct rtx_const *));
static int const_hash_rtx               PROTO((enum machine_mode, rtx));
static int compare_constant_rtx         PROTO((enum machine_mode, rtx,
                                               struct constant_descriptor *));
static struct constant_descriptor *record_constant_rtx PROTO((enum machine_mode,
                                                              rtx));
static struct pool_constant *find_pool_constant PROTO((rtx));
static void mark_constant_pool          PROTO((void));
static void mark_constants              PROTO((rtx));
static int output_addressed_constants   PROTO((tree));
static void output_after_function_constants PROTO((void));
static void output_constructor          PROTO((tree, int));
static void remove_from_pending_weak_list       PROTO ((char *));
#ifdef ASM_OUTPUT_BSS
static void asm_output_bss              PROTO((FILE *, tree, char *, int, int));
#endif
#ifdef BSS_SECTION_ASM_OP
#ifdef ASM_OUTPUT_ALIGNED_BSS
static void asm_output_aligned_bss      PROTO((FILE *, tree, char *, int, int));
#endif
#endif /* BSS_SECTION_ASM_OP */
\f
static enum in_section { no_section, in_text, in_data, in_named
#ifdef BSS_SECTION_ASM_OP
  , in_bss
#endif
#ifdef EH_FRAME_SECTION_ASM_OP
  , in_eh_frame
#endif
#ifdef EXTRA_SECTIONS
  , EXTRA_SECTIONS
#endif
} in_section = no_section;

/* Return a non-zero value if DECL has a section attribute.  */
#define IN_NAMED_SECTION(DECL) \
  ((TREE_CODE (DECL) == FUNCTION_DECL || TREE_CODE (DECL) == VAR_DECL) \
   && DECL_SECTION_NAME (DECL) != NULL_TREE)

/* Text of section name when in_section == in_named.  */
static char *in_named_name;

/* Define functions like text_section for any extra sections.  */
#ifdef EXTRA_SECTION_FUNCTIONS
EXTRA_SECTION_FUNCTIONS
#endif

/* Tell assembler to switch to text section.  */

void
text_section ()
{
  if (in_section != in_text)
    {
      fprintf (asm_out_file, "%s\n", TEXT_SECTION_ASM_OP);
      in_section = in_text;
    }
}

/* Tell assembler to switch to data section.  */

void
data_section ()
{
  if (in_section != in_data)
    {
      if (flag_shared_data)
        {
#ifdef SHARED_SECTION_ASM_OP
          fprintf (asm_out_file, "%s\n", SHARED_SECTION_ASM_OP);
#else
          fprintf (asm_out_file, "%s\n", DATA_SECTION_ASM_OP);
#endif
        }
      else
        fprintf (asm_out_file, "%s\n", DATA_SECTION_ASM_OP);

      in_section = in_data;
    }
}
/* Tell assembler to ALWAYS switch to data section, in case
   it's not sure where it it.  */

void
force_data_section ()
{
  in_section = no_section;
  data_section ();
}

/* Tell assembler to switch to read-only data section.  This is normally
   the text section.  */

void
readonly_data_section ()
{
#ifdef READONLY_DATA_SECTION
  READONLY_DATA_SECTION ();  /* Note this can call data_section.  */
#else
  text_section ();
#endif
}

/* Determine if we're in the text section.  */

int
in_text_section ()
{
  return in_section == in_text;
}

/* Determine if we're in the data section.  */

int
in_data_section ()
{
  return in_section == in_data;
}

/* Tell assembler to change to section NAME for DECL.
   If DECL is NULL, just switch to section NAME.
   If NAME is NULL, get the name from DECL.
   If RELOC is 1, the initializer for DECL contains relocs.  */

void
named_section (decl, name, reloc)
     tree decl;
     const char *name;
     int reloc ATTRIBUTE_UNUSED;
{
  if (decl != NULL_TREE
      && TREE_CODE_CLASS (TREE_CODE (decl)) != 'd')
    abort ();
  if (name == NULL)
    name = TREE_STRING_POINTER (DECL_SECTION_NAME (decl));

  if (in_section != in_named || strcmp (name, in_named_name))
    {
#ifdef ASM_OUTPUT_SECTION_NAME
      ASM_OUTPUT_SECTION_NAME (asm_out_file, decl, name, reloc);
#else
      /* Section attributes are not supported if this macro isn't provided -
         some host formats don't support them at all.  The front-end should
         already have flagged this as an error.  */
      abort ();
#endif

      in_named_name = obstack_alloc (&permanent_obstack, strlen (name) + 1);
      strcpy (in_named_name, name);
      in_section = in_named;
    }
}

#ifdef ASM_OUTPUT_SECTION_NAME
#ifndef UNIQUE_SECTION
#define UNIQUE_SECTION(DECL,RELOC)                              \
do {                                                            \
  int len;                                                      \
  const char *name;                                             \
  char *string;                                                 \
                                                                \
  name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (DECL));       \
  /* Strip off any encoding in name.  */                        \
  STRIP_NAME_ENCODING (name, name);                             \
                                                                \
  len = strlen (name) + 1;                                      \
  string = alloca (len + 1);                                    \
  sprintf (string, ".%s", name);                                \
                                                                \
  DECL_SECTION_NAME (DECL) = build_string (len, string);        \
} while (0)
#endif
#ifndef UNIQUE_SECTION_P
#define UNIQUE_SECTION_P(DECL) 0
#endif
#endif

#ifdef BSS_SECTION_ASM_OP

/* Tell the assembler to switch to the bss section.  */

void
bss_section ()
{
  if (in_section != in_bss)
    {
#ifdef SHARED_BSS_SECTION_ASM_OP
      if (flag_shared_data)
        fprintf (asm_out_file, "%s\n", SHARED_BSS_SECTION_ASM_OP);
      else
#endif
        fprintf (asm_out_file, "%s\n", BSS_SECTION_ASM_OP);

      in_section = in_bss;
    }
}

#ifdef ASM_OUTPUT_BSS

/* Utility function for ASM_OUTPUT_BSS for targets to use if
   they don't support alignments in .bss.
   ??? It is believed that this function will work in most cases so such
   support is localized here.  */

static void
asm_output_bss (file, decl, name, size, rounded)
     FILE *file;
     tree decl;
     char *name;
     int size, rounded;
{
  ASM_GLOBALIZE_LABEL (file, name);
  bss_section ();
#ifdef ASM_DECLARE_OBJECT_NAME
  last_assemble_variable_decl = decl;
  ASM_DECLARE_OBJECT_NAME (file, name, decl);
#else
  /* Standard thing is just output label for the object.  */
  ASM_OUTPUT_LABEL (file, name);
#endif /* ASM_DECLARE_OBJECT_NAME */
  ASM_OUTPUT_SKIP (file, rounded);
}

#endif

#ifdef ASM_OUTPUT_ALIGNED_BSS

/* Utility function for targets to use in implementing
   ASM_OUTPUT_ALIGNED_BSS.
   ??? It is believed that this function will work in most cases so such
   support is localized here.  */

static void
asm_output_aligned_bss (file, decl, name, size, align)
     FILE *file;
     tree decl;
     char *name;
     int size, align;
{
  ASM_GLOBALIZE_LABEL (file, name);
  bss_section ();
  ASM_OUTPUT_ALIGN (file, floor_log2 (align / BITS_PER_UNIT));
#ifdef ASM_DECLARE_OBJECT_NAME
  last_assemble_variable_decl = decl;
  ASM_DECLARE_OBJECT_NAME (file, name, decl);
#else
  /* Standard thing is just output label for the object.  */
  ASM_OUTPUT_LABEL (file, name);
#endif /* ASM_DECLARE_OBJECT_NAME */
  ASM_OUTPUT_SKIP (file, size ? size : 1);
}

#endif

#endif /* BSS_SECTION_ASM_OP */

#ifdef EH_FRAME_SECTION_ASM_OP
void
eh_frame_section ()
{
  if (in_section != in_eh_frame)
    {
      fprintf (asm_out_file, "%s\n", EH_FRAME_SECTION_ASM_OP);
      in_section = in_eh_frame;
    }
} 
#endif

/* Switch to the section for function DECL.

   If DECL is NULL_TREE, switch to the text section.
   ??? It's not clear that we will ever be passed NULL_TREE, but it's
   safer to handle it.  */

void
function_section (decl)
     tree decl;
{
  if (decl != NULL_TREE
      && DECL_SECTION_NAME (decl) != NULL_TREE)
    named_section (decl, (char *) 0, 0);
  else
    text_section ();
}

/* Switch to section for variable DECL.

   RELOC is the `reloc' argument to SELECT_SECTION.  */

void
variable_section (decl, reloc)
     tree decl;
     int reloc;
{
  if (IN_NAMED_SECTION (decl))
    named_section (decl, NULL, reloc);
  else
    {
      /* C++ can have const variables that get initialized from constructors,
         and thus can not be in a readonly section.  We prevent this by
         verifying that the initial value is constant for objects put in a
         readonly section.

         error_mark_node is used by the C front end to indicate that the
         initializer has not been seen yet.  In this case, we assume that
         the initializer must be constant.

         C++ uses error_mark_node for variables that have complicated
         initializers, but these variables go in BSS so we won't be called
         for them.  */

#ifdef SELECT_SECTION
      SELECT_SECTION (decl, reloc);
#else
      if (DECL_READONLY_SECTION (decl, reloc))
        readonly_data_section ();
      else
        data_section ();
#endif
    }
}

/* Tell assembler to switch to the section for the exception handling
   table.  */

void
exception_section ()
{
#if defined (EXCEPTION_SECTION)
  EXCEPTION_SECTION ();
#else
#ifdef ASM_OUTPUT_SECTION_NAME
  named_section (NULL_TREE, ".gcc_except_table", 0);
#else
  if (flag_pic)
    data_section ();
  else
    readonly_data_section ();
#endif
#endif
}
\f
/* Create the rtl to represent a function, for a function definition.
   DECL is a FUNCTION_DECL node which describes which function.
   The rtl is stored into DECL.  */

void
make_function_rtl (decl)
     tree decl;
{
  char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
  char *new_name = name;

  /* Rename a nested function to avoid conflicts.  */
  if (decl_function_context (decl) != 0
      && DECL_INITIAL (decl) != 0
      && DECL_RTL (decl) == 0)
    {
      char *label;

      name = IDENTIFIER_POINTER (DECL_NAME (decl));
      ASM_FORMAT_PRIVATE_NAME (label, name, var_labelno);
      name = obstack_copy0 (saveable_obstack, label, strlen (label));
      var_labelno++;
    }
  else
    {
      /* When -fprefix-function-name is used, every function name is
         prefixed.  Even static functions are prefixed because they
         could be declared latter.  Note that a nested function name
         is not prefixed.  */
      if (flag_prefix_function_name)
        {
          new_name = (char *) alloca (strlen (name) + CHKR_PREFIX_SIZE + 1);
          strcpy (new_name, CHKR_PREFIX);
          strcpy (new_name + CHKR_PREFIX_SIZE, name);
          name = obstack_copy0 (saveable_obstack, new_name, strlen (new_name));
        }
    }

  if (DECL_RTL (decl) == 0)
    {
      DECL_RTL (decl)
        = gen_rtx_MEM (DECL_MODE (decl),
                       gen_rtx_SYMBOL_REF (Pmode, name));

      /* Optionally set flags or add text to the name to record information
         such as that it is a function name.  If the name is changed, the macro
         ASM_OUTPUT_LABELREF will have to know how to strip this information.  */
#ifdef ENCODE_SECTION_INFO
      ENCODE_SECTION_INFO (decl);
#endif
    }
  else
    {
      /* ??? Another way to do this would be to do what halfpic.c does
         and maintain a hashed table of such critters.  */
      /* ??? Another way to do this would be to pass a flag bit to
         ENCODE_SECTION_INFO saying whether this is a new decl or not.  */
      /* Let the target reassign the RTL if it wants.
         This is necessary, for example, when one machine specific
         decl attribute overrides another.  */
#ifdef REDO_SECTION_INFO_P
      if (REDO_SECTION_INFO_P (decl))
        ENCODE_SECTION_INFO (decl);
#endif
    }

  /* Record at least one function has been defined.  */
  function_defined = 1;
}

/* Given NAME, a putative register name, discard any customary prefixes.  */

static const char *
strip_reg_name (name)
  const char *name;
{
#ifdef REGISTER_PREFIX
  if (!strncmp (name, REGISTER_PREFIX, strlen (REGISTER_PREFIX)))
    name += strlen (REGISTER_PREFIX);
#endif
  if (name[0] == '%' || name[0] == '#')
    name++;
  return name;
}
\f
/* Decode an `asm' spec for a declaration as a register name.
   Return the register number, or -1 if nothing specified,
   or -2 if the ASMSPEC is not `cc' or `memory' and is not recognized,
   or -3 if ASMSPEC is `cc' and is not recognized,
   or -4 if ASMSPEC is `memory' and is not recognized.
   Accept an exact spelling or a decimal number.
   Prefixes such as % are optional.  */

int
decode_reg_name (asmspec)
  const char *asmspec;
{
  if (asmspec != 0)
    {
      int i;

      /* Get rid of confusing prefixes.  */
      asmspec = strip_reg_name (asmspec);
        
      /* Allow a decimal number as a "register name".  */
      for (i = strlen (asmspec) - 1; i >= 0; i--)
        if (! (asmspec[i] >= '0' && asmspec[i] <= '9'))
          break;
      if (asmspec[0] != 0 && i < 0)
        {
          i = atoi (asmspec);
          if (i < FIRST_PSEUDO_REGISTER && i >= 0)
            return i;
          else
            return -2;
        }

      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
        if (reg_names[i][0]
            && ! strcmp (asmspec, strip_reg_name (reg_names[i])))
          return i;

#ifdef ADDITIONAL_REGISTER_NAMES
      {
        static struct { const char *name; int number; } table[]
          = ADDITIONAL_REGISTER_NAMES;

        for (i = 0; i < (int)(sizeof (table) / sizeof (table[0])); i++)
          if (! strcmp (asmspec, table[i].name))
            return table[i].number;
      }
#endif /* ADDITIONAL_REGISTER_NAMES */

      if (!strcmp (asmspec, "memory"))
        return -4;

      if (!strcmp (asmspec, "cc"))
        return -3;

      return -2;
    }

  return -1;
}
\f
/* Create the DECL_RTL for a declaration for a static or external variable
   or static or external function.
   ASMSPEC, if not 0, is the string which the user specified
   as the assembler symbol name.
   TOP_LEVEL is nonzero if this is a file-scope variable.

   This is never called for PARM_DECL nodes.  */

void
make_decl_rtl (decl, asmspec, top_level)
     tree decl;
     const char *asmspec;
     int top_level;
{
  register char *name = 0;
  int reg_number;

  reg_number = decode_reg_name (asmspec);

  if (DECL_ASSEMBLER_NAME (decl) != NULL_TREE)
    name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));

  if (reg_number == -2)
    {
      /* ASMSPEC is given, and not the name of a register.  */
      name = (char *) obstack_alloc (saveable_obstack,
                                     strlen (asmspec) + 2);
      name[0] = '*';
      strcpy (&name[1], asmspec);
    }

  /* For a duplicate declaration, we can be called twice on the
     same DECL node.  Don't discard the RTL already made.  */
  if (DECL_RTL (decl) == 0)
    {
      /* First detect errors in declaring global registers.  */
      if (TREE_CODE (decl) != FUNCTION_DECL
          && DECL_REGISTER (decl) && reg_number == -1)
        error_with_decl (decl,
                         "register name not specified for `%s'");
      else if (TREE_CODE (decl) != FUNCTION_DECL
               && DECL_REGISTER (decl) && reg_number < 0)
        error_with_decl (decl,
                         "invalid register name for `%s'");
      else if ((reg_number >= 0 || reg_number == -3)
               && (TREE_CODE (decl) == FUNCTION_DECL
                   && ! DECL_REGISTER (decl)))
        error_with_decl (decl,
                         "register name given for non-register variable `%s'");
      else if (TREE_CODE (decl) != FUNCTION_DECL
               && DECL_REGISTER (decl)
               && TYPE_MODE (TREE_TYPE (decl)) == BLKmode)
        error_with_decl (decl,
                         "data type of `%s' isn't suitable for a register");
      else if (TREE_CODE (decl) != FUNCTION_DECL && DECL_REGISTER (decl)
               && ! HARD_REGNO_MODE_OK (reg_number,
                                        TYPE_MODE (TREE_TYPE (decl))))
        error_with_decl (decl,
                         "register number for `%s' isn't suitable for data type");
      /* Now handle properly declared static register variables.  */
      else if (TREE_CODE (decl) != FUNCTION_DECL && DECL_REGISTER (decl))
        {
          int nregs;

          if (DECL_INITIAL (decl) != 0 && top_level)
            {
              DECL_INITIAL (decl) = 0;
              error ("global register variable has initial value");
            }
          if (fixed_regs[reg_number] == 0
              && function_defined && top_level)
            error ("global register variable follows a function definition");
          if (TREE_THIS_VOLATILE (decl))
            warning ("volatile register variables don't work as you might wish");

          /* If the user specified one of the eliminables registers here,
             e.g., FRAME_POINTER_REGNUM, we don't want to get this variable
             confused with that register and be eliminated.  Although this
             usage is somewhat suspect, we nevertheless use the following
             kludge to avoid setting DECL_RTL to frame_pointer_rtx.  */

          DECL_RTL (decl)
            = gen_rtx_REG (DECL_MODE (decl), FIRST_PSEUDO_REGISTER);
          REGNO (DECL_RTL (decl)) = reg_number;
          REG_USERVAR_P (DECL_RTL (decl)) = 1;

          if (top_level)
            {
              /* Make this register global, so not usable for anything
                 else.  */
#ifdef ASM_DECLARE_REGISTER_GLOBAL
              ASM_DECLARE_REGISTER_GLOBAL (asm_out_file, decl, reg_number, name);
#endif
              nregs = HARD_REGNO_NREGS (reg_number, DECL_MODE (decl));
              while (nregs > 0)
                globalize_reg (reg_number + --nregs);
            }
        }
      /* Specifying a section attribute on a variable forces it into a
         non-.bss section, and thus it cannot be common. */
      else if (TREE_CODE (decl) == VAR_DECL
               && DECL_SECTION_NAME (decl) != NULL_TREE
               && DECL_INITIAL (decl) == NULL_TREE
               && DECL_COMMON (decl))
          DECL_COMMON (decl) = 0;

      /* Now handle ordinary static variables and functions (in memory).
         Also handle vars declared register invalidly.  */
      if (DECL_RTL (decl) == 0)
        {
          /* Can't use just the variable's own name for a variable
             whose scope is less than the whole file.
             Concatenate a distinguishing number.  */
          if (!top_level && !TREE_PUBLIC (decl) && asmspec == 0)
            {
              char *label;

              ASM_FORMAT_PRIVATE_NAME (label, name, var_labelno);
              name = obstack_copy0 (saveable_obstack, label, strlen (label));
              var_labelno++;
            }

          if (name == 0)
            abort ();

          /* When -fprefix-function-name is used, the functions
             names are prefixed.  Only nested function names are not
             prefixed.  */
          if (flag_prefix_function_name && TREE_CODE (decl) == FUNCTION_DECL)
            {
              char *new_name;
              new_name = (char *) alloca (strlen (name) + CHKR_PREFIX_SIZE 
                                          + 1);
              strcpy (new_name, CHKR_PREFIX);
              strcpy (new_name + CHKR_PREFIX_SIZE, name);
              name = obstack_copy0 (saveable_obstack,
                                   new_name, strlen (new_name));
            }

          DECL_RTL (decl) = gen_rtx_MEM (DECL_MODE (decl),
                                         gen_rtx_SYMBOL_REF (Pmode, name));
          MEM_ALIAS_SET (DECL_RTL (decl)) = get_alias_set (decl);
            
          /* If this variable is to be treated as volatile, show its
             tree node has side effects.  If it has side effects, either
             because of this test or from TREE_THIS_VOLATILE also
             being set, show the MEM is volatile.  */
          if (flag_volatile_global && TREE_CODE (decl) == VAR_DECL
              && TREE_PUBLIC (decl))
            TREE_SIDE_EFFECTS (decl) = 1;
          else if (flag_volatile_static && TREE_CODE (decl) == VAR_DECL
               && (TREE_PUBLIC (decl) || TREE_STATIC (decl)))
            TREE_SIDE_EFFECTS (decl) = 1;

          if (TREE_SIDE_EFFECTS (decl))
            MEM_VOLATILE_P (DECL_RTL (decl)) = 1;

          if (TREE_READONLY (decl))
            RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
          MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
                               AGGREGATE_TYPE_P (TREE_TYPE (decl)));

          /* Optionally set flags or add text to the name to record information
             such as that it is a function name.
             If the name is changed, the macro ASM_OUTPUT_LABELREF
             will have to know how to strip this information.  */
#ifdef ENCODE_SECTION_INFO
          ENCODE_SECTION_INFO (decl);
#endif
        }
    }
  else
    {
      /* If the old RTL had the wrong mode, fix the mode.  */
      if (GET_MODE (DECL_RTL (decl)) != DECL_MODE (decl))
        {
          rtx rtl = DECL_RTL (decl);
          PUT_MODE (rtl, DECL_MODE (decl));
        }

      /* ??? Another way to do this would be to do what halfpic.c does
         and maintain a hashed table of such critters.  */
      /* ??? Another way to do this would be to pass a flag bit to
         ENCODE_SECTION_INFO saying whether this is a new decl or not.  */
      /* Let the target reassign the RTL if it wants.
         This is necessary, for example, when one machine specific
         decl attribute overrides another.  */
#ifdef REDO_SECTION_INFO_P
      if (REDO_SECTION_INFO_P (decl))
        ENCODE_SECTION_INFO (decl);
#endif
    }
}

/* Make the rtl for variable VAR be volatile.
   Use this only for static variables.  */

void
make_var_volatile (var)
     tree var;
{
  if (GET_CODE (DECL_RTL (var)) != MEM)
    abort ();

  MEM_VOLATILE_P (DECL_RTL (var)) = 1;
}
\f
/* Output alignment directive to align for constant expression EXP.  */

void
assemble_constant_align (exp)
     tree exp;
{
  int align;

  /* Align the location counter as required by EXP's data type.  */
  align = TYPE_ALIGN (TREE_TYPE (exp));
#ifdef CONSTANT_ALIGNMENT
  align = CONSTANT_ALIGNMENT (exp, align);
#endif

  if (align > BITS_PER_UNIT)
    ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT));
}

/* Output a string of literal assembler code
   for an `asm' keyword used between functions.  */

void
assemble_asm (string)
     tree string;
{
  app_enable ();

  if (TREE_CODE (string) == ADDR_EXPR)
    string = TREE_OPERAND (string, 0);

  fprintf (asm_out_file, "\t%s\n", TREE_STRING_POINTER (string));
}

#if 0 /* This should no longer be needed, because
         flag_gnu_linker should be 0 on these systems,
         which should prevent any output
         if ASM_OUTPUT_CONSTRUCTOR and ASM_OUTPUT_DESTRUCTOR are absent.  */
#if !(defined(DBX_DEBUGGING_INFO) && !defined(FASCIST_ASSEMBLER))
#ifndef ASM_OUTPUT_CONSTRUCTOR
#define ASM_OUTPUT_CONSTRUCTOR(file, name)
#endif
#ifndef ASM_OUTPUT_DESTRUCTOR
#define ASM_OUTPUT_DESTRUCTOR(file, name)
#endif
#endif
#endif /* 0 */

/* Record an element in the table of global destructors.
   How this is done depends on what sort of assembler and linker
   are in use.

   NAME should be the name of a global function to be called
   at exit time.  This name is output using assemble_name.  */

void
assemble_destructor (name)
     char *name;
{
#ifdef ASM_OUTPUT_DESTRUCTOR
  ASM_OUTPUT_DESTRUCTOR (asm_out_file, name);
#else
  if (flag_gnu_linker)
    {
      /* Now tell GNU LD that this is part of the static destructor set.  */
      /* This code works for any machine provided you use GNU as/ld.  */
      fprintf (asm_out_file, "%s \"___DTOR_LIST__\",22,0,0,", ASM_STABS_OP);
      assemble_name (asm_out_file, name);
      fputc ('\n', asm_out_file);
    }
#endif
}

/* Likewise for global constructors.  */

void
assemble_constructor (name)
     char *name;
{
#ifdef ASM_OUTPUT_CONSTRUCTOR
  ASM_OUTPUT_CONSTRUCTOR (asm_out_file, name);
#else
  if (flag_gnu_linker)
    {
      /* Now tell GNU LD that this is part of the static constructor set.  */
      /* This code works for any machine provided you use GNU as/ld.  */
      fprintf (asm_out_file, "%s \"___CTOR_LIST__\",22,0,0,", ASM_STABS_OP);
      assemble_name (asm_out_file, name);
      fputc ('\n', asm_out_file);
    }
#endif
}

/* Likewise for entries we want to record for garbage collection.
   Garbage collection is still under development.  */

void
assemble_gc_entry (name)
     char *name;
{
#ifdef ASM_OUTPUT_GC_ENTRY
  ASM_OUTPUT_GC_ENTRY (asm_out_file, name);
#else
  if (flag_gnu_linker)
    {
      /* Now tell GNU LD that this is part of the static constructor set.  */
      fprintf (asm_out_file, "%s \"___PTR_LIST__\",22,0,0,", ASM_STABS_OP);
      assemble_name (asm_out_file, name);
      fputc ('\n', asm_out_file);
    }
#endif
}
\f
/* CONSTANT_POOL_BEFORE_FUNCTION may be defined as an expression with
   a non-zero value if the constant pool should be output before the
   start of the function, or a zero value if the pool should output
   after the end of the function.  The default is to put it before the
   start.  */

#ifndef CONSTANT_POOL_BEFORE_FUNCTION
#define CONSTANT_POOL_BEFORE_FUNCTION 1
#endif

/* Output assembler code for the constant pool of a function and associated
   with defining the name of the function.  DECL describes the function.
   NAME is the function's name.  For the constant pool, we use the current
   constant pool data.  */

void
assemble_start_function (decl, fnname)
     tree decl;
     char *fnname;
{
  int align;

  /* The following code does not need preprocessing in the assembler.  */

  app_disable ();

  if (CONSTANT_POOL_BEFORE_FUNCTION)
    output_constant_pool (fnname, decl);

#ifdef ASM_OUTPUT_SECTION_NAME
  /* If the function is to be put in its own section and it's not in a section
     already, indicate so.  */
  if ((flag_function_sections
       && DECL_SECTION_NAME (decl) == NULL_TREE)
      || UNIQUE_SECTION_P (decl))
    UNIQUE_SECTION (decl, 0);
#endif

  function_section (decl);

  /* Tell assembler to move to target machine's alignment for functions.  */
  align = floor_log2 (FUNCTION_BOUNDARY / BITS_PER_UNIT);
  if (align > 0)
    ASM_OUTPUT_ALIGN (asm_out_file, align);

#ifdef ASM_OUTPUT_FUNCTION_PREFIX
  ASM_OUTPUT_FUNCTION_PREFIX (asm_out_file, fnname);
#endif

#ifdef SDB_DEBUGGING_INFO
  /* Output SDB definition of the function.  */
  if (write_symbols == SDB_DEBUG)
    sdbout_mark_begin_function ();
#endif

#ifdef DBX_DEBUGGING_INFO
  /* Output DBX definition of the function.  */
  if (write_symbols == DBX_DEBUG)
    dbxout_begin_function (decl);
#endif

  /* Make function name accessible from other files, if appropriate.  */

  if (TREE_PUBLIC (decl))
    {
      if (! first_global_object_name)
        {
          const char *p;
          char **name;

          if (! DECL_WEAK (decl) && ! DECL_ONE_ONLY (decl))
            name = &first_global_object_name;
          else
            name = &weak_global_object_name;

          STRIP_NAME_ENCODING (p, fnname);
          *name = permalloc (strlen (p) + 1);
          strcpy (*name, p);
        }

#ifdef ASM_WEAKEN_LABEL
      if (DECL_WEAK (decl))
        {
          ASM_WEAKEN_LABEL (asm_out_file, fnname);
          /* Remove this function from the pending weak list so that
             we do not emit multiple .weak directives for it.  */
          remove_from_pending_weak_list
            (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)));
        }
      else
#endif
      ASM_GLOBALIZE_LABEL (asm_out_file, fnname);
    }

  /* Do any machine/system dependent processing of the function name */
#ifdef ASM_DECLARE_FUNCTION_NAME
  ASM_DECLARE_FUNCTION_NAME (asm_out_file, fnname, current_function_decl);
#else
  /* Standard thing is just output label for the function.  */
  ASM_OUTPUT_LABEL (asm_out_file, fnname);
#endif /* ASM_DECLARE_FUNCTION_NAME */
}

/* Output assembler code associated with defining the size of the
   function.  DECL describes the function.  NAME is the function's name.  */

void
assemble_end_function (decl, fnname)
     tree decl;
     char *fnname;
{
#ifdef ASM_DECLARE_FUNCTION_SIZE
  ASM_DECLARE_FUNCTION_SIZE (asm_out_file, fnname, decl);
#endif
  if (! CONSTANT_POOL_BEFORE_FUNCTION)
    {
      output_constant_pool (fnname, decl);
      function_section (decl);  /* need to switch back */
    }

  /* Output any constants which should appear after the function.  */
  output_after_function_constants ();
}
\f
/* Assemble code to leave SIZE bytes of zeros.  */

void
assemble_zeros (size)
     int size;
{
  /* Do no output if -fsyntax-only.  */
  if (flag_syntax_only)
    return;

#ifdef ASM_NO_SKIP_IN_TEXT
  /* The `space' pseudo in the text section outputs nop insns rather than 0s,
     so we must output 0s explicitly in the text section.  */
  if (ASM_NO_SKIP_IN_TEXT && in_text_section ())
    {
      int i;

      for (i = 0; i < size - 20; i += 20)
        {
#ifdef ASM_BYTE_OP
          fprintf (asm_out_file,
                   "%s 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0\n", ASM_BYTE_OP);
#else
          fprintf (asm_out_file,
                   "\tbyte 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0\n");
#endif
        }
      if (i < size)
        {
#ifdef ASM_BYTE_OP
          fprintf (asm_out_file, "%s 0", ASM_BYTE_OP);
#else
          fprintf (asm_out_file, "\tbyte 0");
#endif
          i++;
          for (; i < size; i++)
            fprintf (asm_out_file, ",0");
          fprintf (asm_out_file, "\n");
        }
    }
  else
#endif
    if (size > 0)
      ASM_OUTPUT_SKIP (asm_out_file, size);
}

/* Assemble an alignment pseudo op for an ALIGN-bit boundary.  */

void
assemble_align (align)
     int align;
{
  if (align > BITS_PER_UNIT)
    ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT));
}

/* Assemble a string constant with the specified C string as contents.  */

void
assemble_string (p, size)
     const char *p;
     int size;
{
  int pos = 0;
  int maximum = 2000;

  /* If the string is very long, split it up.  */

  while (pos < size)
    {
      int thissize = size - pos;
      if (thissize > maximum)
        thissize = maximum;

      ASM_OUTPUT_ASCII (asm_out_file, p, thissize);

      pos += thissize;
      p += thissize;
    }
}

\f
/* Assemble everything that is needed for a variable or function declaration.
   Not used for automatic variables, and not used for function definitions.
   Should not be called for variables of incomplete structure type.

   TOP_LEVEL is nonzero if this variable has file scope.
   AT_END is nonzero if this is the special handling, at end of compilation,
   to define things that have had only tentative definitions.
   DONT_OUTPUT_DATA if nonzero means don't actually output the
   initial value (that will be done by the caller).  */

void
assemble_variable (decl, top_level, at_end, dont_output_data)
     tree decl;
     int top_level ATTRIBUTE_UNUSED;
     int at_end;
     int dont_output_data;
{
  register char *name;
  unsigned int align;
  tree size_tree = NULL_TREE;
  int reloc = 0;
  enum in_section saved_in_section;

  last_assemble_variable_decl = 0;

  if (GET_CODE (DECL_RTL (decl)) == REG)
    {
      /* Do output symbol info for global register variables, but do nothing
         else for them.  */

      if (TREE_ASM_WRITTEN (decl))
        return;
      TREE_ASM_WRITTEN (decl) = 1;

      /* Do no output if -fsyntax-only.  */
      if (flag_syntax_only)
        return;

#if defined (DBX_DEBUGGING_INFO) || defined (XCOFF_DEBUGGING_INFO)
      /* File-scope global variables are output here.  */
      if ((write_symbols == DBX_DEBUG || write_symbols == XCOFF_DEBUG)
           && top_level)
        dbxout_symbol (decl, 0);
#endif
#ifdef SDB_DEBUGGING_INFO
      if (write_symbols == SDB_DEBUG && top_level
          /* Leave initialized global vars for end of compilation;
             see comment in compile_file.  */
          && (TREE_PUBLIC (decl) == 0 || DECL_INITIAL (decl) == 0))
        sdbout_symbol (decl, 0);
#endif

      /* Don't output any DWARF debugging information for variables here.
         In the case of local variables, the information for them is output
         when we do our recursive traversal of the tree representation for
         the entire containing function.  In the case of file-scope variables,
         we output information for all of them at the very end of compilation
         while we are doing our final traversal of the chain of file-scope
         declarations.  */

      return;
    }

  /* Normally no need to say anything here for external references,
     since assemble_external is called by the language-specific code
     when a declaration is first seen.  */

  if (DECL_EXTERNAL (decl))
    return;

  /* Output no assembler code for a function declaration.
     Only definitions of functions output anything.  */

  if (TREE_CODE (decl) == FUNCTION_DECL)
    return;

  /* If type was incomplete when the variable was declared,
     see if it is complete now.  */

  if (DECL_SIZE (decl) == 0)
    layout_decl (decl, 0);

  /* Still incomplete => don't allocate it; treat the tentative defn
     (which is what it must have been) as an `extern' reference.  */

  if (!dont_output_data && DECL_SIZE (decl) == 0)
    {
      error_with_file_and_line (DECL_SOURCE_FILE (decl),
                                DECL_SOURCE_LINE (decl),
                                "storage size of `%s' isn't known",
                                IDENTIFIER_POINTER (DECL_NAME (decl)));
      TREE_ASM_WRITTEN (decl) = 1;
      return;
    }

  /* The first declaration of a variable that comes through this function
     decides whether it is global (in C, has external linkage)
     or local (in C, has internal linkage).  So do nothing more
     if this function has already run.  */

  if (TREE_ASM_WRITTEN (decl))
    return;

  TREE_ASM_WRITTEN (decl) = 1;

  /* Do no output if -fsyntax-only.  */
  if (flag_syntax_only)
    return;

  app_disable ();

  if (! dont_output_data)
    {
      int size;

      if (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
        goto finish;

      /* This is better than explicit arithmetic, since it avoids overflow.  */
      size_tree = size_binop (CEIL_DIV_EXPR,
                              DECL_SIZE (decl), size_int (BITS_PER_UNIT));

      size = TREE_INT_CST_LOW (size_tree);
      if (TREE_INT_CST_HIGH (size_tree) != 0
          || size != TREE_INT_CST_LOW (size_tree))
        {
          error_with_decl (decl, "size of variable `%s' is too large");
          goto finish;
        }
    }

  name = XSTR (XEXP (DECL_RTL (decl), 0), 0);

  if (TREE_PUBLIC (decl) && DECL_NAME (decl)
      && ! first_global_object_name
      && ! (DECL_COMMON (decl) && (DECL_INITIAL (decl) == 0
                                   || DECL_INITIAL (decl) == error_mark_node))
      && ! DECL_WEAK (decl)
      && ! DECL_ONE_ONLY (decl))
    {
      const char *p;

      STRIP_NAME_ENCODING (p, name);
      first_global_object_name = permalloc (strlen (p) + 1);
      strcpy (first_global_object_name, p);
    }

  /* Compute the alignment of this data.  */

  align = DECL_ALIGN (decl);

  /* In the case for initialing an array whose length isn't specified,
     where we have not yet been able to do the layout,
     figure out the proper alignment now.  */
  if (dont_output_data && DECL_SIZE (decl) == 0
      && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
    align = MAX (align, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));

  /* Some object file formats have a maximum alignment which they support.
     In particular, a.out format supports a maximum alignment of 4.  */
#ifndef MAX_OFILE_ALIGNMENT
#define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
#endif
  if (align > MAX_OFILE_ALIGNMENT)
    {
      warning_with_decl (decl,
        "alignment of `%s' is greater than maximum object file alignment. Using %d.",
                    MAX_OFILE_ALIGNMENT/BITS_PER_UNIT);
      align = MAX_OFILE_ALIGNMENT;
    }

  /* On some machines, it is good to increase alignment sometimes.  */
#ifdef DATA_ALIGNMENT
  align = DATA_ALIGNMENT (TREE_TYPE (decl), align);
#endif
#ifdef CONSTANT_ALIGNMENT
  if (DECL_INITIAL (decl) != 0 && DECL_INITIAL (decl) != error_mark_node)
    align = CONSTANT_ALIGNMENT (DECL_INITIAL (decl), align);
#endif

  /* Reset the alignment in case we have made it tighter, so we can benefit
     from it in get_pointer_alignment.  */
  DECL_ALIGN (decl) = align;

  /* Handle uninitialized definitions.  */

  if ((DECL_INITIAL (decl) == 0 || DECL_INITIAL (decl) == error_mark_node)
      /* If the target can't output uninitialized but not common global data
         in .bss, then we have to use .data.  */
#if ! defined (ASM_OUTPUT_BSS) && ! defined (ASM_OUTPUT_ALIGNED_BSS)
      && DECL_COMMON (decl)
#endif
      && DECL_SECTION_NAME (decl) == 0
      && ! dont_output_data)
    {
      int size = TREE_INT_CST_LOW (size_tree);
      int rounded = size;

      /* Don't allocate zero bytes of common,
         since that means "undefined external" in the linker.  */
      if (size == 0) rounded = 1;
      /* Round size up to multiple of BIGGEST_ALIGNMENT bits
         so that each uninitialized object starts on such a boundary.  */
      rounded += (BIGGEST_ALIGNMENT / BITS_PER_UNIT) - 1;
      rounded = (rounded / (BIGGEST_ALIGNMENT / BITS_PER_UNIT)
                 * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
      
#if !defined(ASM_OUTPUT_ALIGNED_COMMON) && !defined(ASM_OUTPUT_ALIGNED_BSS)
      if ( (DECL_ALIGN (decl) / BITS_PER_UNIT) > rounded)
         warning_with_decl 
           (decl, "requested alignment for %s is greater than implemented alignment of %d.",rounded);
#endif
       
#ifdef DBX_DEBUGGING_INFO
      /* File-scope global variables are output here.  */
      if (write_symbols == DBX_DEBUG && top_level)
        dbxout_symbol (decl, 0);
#endif
#ifdef SDB_DEBUGGING_INFO
      if (write_symbols == SDB_DEBUG && top_level
          /* Leave initialized global vars for end of compilation;
             see comment in compile_file.  */
          && (TREE_PUBLIC (decl) == 0 || DECL_INITIAL (decl) == 0))
        sdbout_symbol (decl, 0);
#endif

      /* Don't output any DWARF debugging information for variables here.
         In the case of local variables, the information for them is output
         when we do our recursive traversal of the tree representation for
         the entire containing function.  In the case of file-scope variables,
         we output information for all of them at the very end of compilation
         while we are doing our final traversal of the chain of file-scope
         declarations.  */

#if 0 /* ??? We should either delete this or add a comment describing what
         it was intended to do and why we shouldn't delete it.  */
      if (flag_shared_data)
        data_section ();
#endif

      if (TREE_PUBLIC (decl)
#if defined (ASM_OUTPUT_BSS) || defined (ASM_OUTPUT_ALIGNED_BSS)
          && DECL_COMMON (decl)
#endif
          )
        {
#ifdef ASM_OUTPUT_SHARED_COMMON
          if (flag_shared_data)
            ASM_OUTPUT_SHARED_COMMON (asm_out_file, name, size, rounded);
          else
#endif
              {
#ifdef ASM_OUTPUT_ALIGNED_DECL_COMMON
                ASM_OUTPUT_ALIGNED_DECL_COMMON (asm_out_file, decl, name, size,
                                                   DECL_ALIGN (decl));
#else
#ifdef ASM_OUTPUT_ALIGNED_COMMON
                ASM_OUTPUT_ALIGNED_COMMON (asm_out_file, name, size,
                                           DECL_ALIGN (decl));
#else
                ASM_OUTPUT_COMMON (asm_out_file, name, size, rounded);
#endif
#endif
              }
        }
#if defined (ASM_OUTPUT_BSS) || defined (ASM_OUTPUT_ALIGNED_BSS)
      else if (TREE_PUBLIC (decl))
        {
#ifdef ASM_OUTPUT_SHARED_BSS
          if (flag_shared_data)
            ASM_OUTPUT_SHARED_BSS (asm_out_file, decl, name, size, rounded);
          else
#endif
              {
#ifdef ASM_OUTPUT_ALIGNED_BSS
                ASM_OUTPUT_ALIGNED_BSS (asm_out_file, decl, name, size,
                                        DECL_ALIGN (decl));
#else
                ASM_OUTPUT_BSS (asm_out_file, decl, name, size, rounded);
#endif
              }
        }
#endif /* ASM_OUTPUT_BSS || ASM_OUTPUT_ALIGNED_BSS */
      else
        {
#ifdef ASM_OUTPUT_SHARED_LOCAL
          if (flag_shared_data)
            ASM_OUTPUT_SHARED_LOCAL (asm_out_file, name, size, rounded);
          else
#endif
              {
#ifdef ASM_OUTPUT_ALIGNED_DECL_LOCAL
                ASM_OUTPUT_ALIGNED_DECL_LOCAL (asm_out_file, decl, name, size,
                                                  DECL_ALIGN (decl));
#else
#ifdef ASM_OUTPUT_ALIGNED_LOCAL
                ASM_OUTPUT_ALIGNED_LOCAL (asm_out_file, name, size,
                                          DECL_ALIGN (decl));
#else
                ASM_OUTPUT_LOCAL (asm_out_file, name, size, rounded);
#endif
#endif
              }
        }
      goto finish;
    }

  /* Handle initialized definitions.
     Also handle uninitialized global definitions if -fno-common and the
     target doesn't support ASM_OUTPUT_BSS.  */

  /* First make the assembler name(s) global if appropriate.  */
  if (TREE_PUBLIC (decl) && DECL_NAME (decl))
    {
#ifdef ASM_WEAKEN_LABEL
      if (DECL_WEAK (decl)) 
        {
          ASM_WEAKEN_LABEL (asm_out_file, name);
           /* Remove this variable from the pending weak list so that
              we do not emit multiple .weak directives for it.  */
          remove_from_pending_weak_list
            (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)));
        }
      else
#endif
      ASM_GLOBALIZE_LABEL (asm_out_file, name);
    }
#if 0
  for (d = equivalents; d; d = TREE_CHAIN (d))
    {
      tree e = TREE_VALUE (d);
      if (TREE_PUBLIC (e) && DECL_NAME (e))
        ASM_GLOBALIZE_LABEL (asm_out_file,
                             XSTR (XEXP (DECL_RTL (e), 0), 0));
    }
#endif

  /* Output any data that we will need to use the address of.  */
  if (DECL_INITIAL (decl) == error_mark_node)
    reloc = contains_pointers_p (TREE_TYPE (decl));
  else if (DECL_INITIAL (decl))
    reloc = output_addressed_constants (DECL_INITIAL (decl));

#ifdef ASM_OUTPUT_SECTION_NAME
  if ((flag_data_sections != 0
       && DECL_SECTION_NAME (decl) == NULL_TREE)
      || UNIQUE_SECTION_P (decl))
    UNIQUE_SECTION (decl, reloc);
#endif

  /* Switch to the appropriate section.  */
  variable_section (decl, reloc);

  /* dbxout.c needs to know this.  */
  if (in_text_section ())
    DECL_IN_TEXT_SECTION (decl) = 1;

  /* Record current section so we can restore it if dbxout.c clobbers it.  */
  saved_in_section = in_section;

  /* Output the dbx info now that we have chosen the section.  */

#ifdef DBX_DEBUGGING_INFO
  /* File-scope global variables are output here.  */
  if (write_symbols == DBX_DEBUG && top_level)
    dbxout_symbol (decl, 0);
#endif
#ifdef SDB_DEBUGGING_INFO
  if (write_symbols == SDB_DEBUG && top_level
      /* Leave initialized global vars for end of compilation;
         see comment in compile_file.  */
      && (TREE_PUBLIC (decl) == 0 || DECL_INITIAL (decl) == 0))
    sdbout_symbol (decl, 0);
#endif

  /* Don't output any DWARF debugging information for variables here.
     In the case of local variables, the information for them is output
     when we do our recursive traversal of the tree representation for
     the entire containing function.  In the case of file-scope variables,
     we output information for all of them at the very end of compilation
     while we are doing our final traversal of the chain of file-scope
     declarations.  */

  /* If the debugging output changed sections, reselect the section
     that's supposed to be selected.  */
  if (in_section != saved_in_section)
    variable_section (decl, reloc);

  /* Output the alignment of this data.  */
  if (align > BITS_PER_UNIT)
    ASM_OUTPUT_ALIGN (asm_out_file,
                      floor_log2 (DECL_ALIGN (decl) / BITS_PER_UNIT));

  /* Do any machine/system dependent processing of the object.  */
#ifdef ASM_DECLARE_OBJECT_NAME
  last_assemble_variable_decl = decl;
  ASM_DECLARE_OBJECT_NAME (asm_out_file, name, decl);
#else
  /* Standard thing is just output label for the object.  */
  ASM_OUTPUT_LABEL (asm_out_file, name);
#endif /* ASM_DECLARE_OBJECT_NAME */

  if (!dont_output_data)
    {
      if (DECL_INITIAL (decl))
        /* Output the actual data.  */
        output_constant (DECL_INITIAL (decl), TREE_INT_CST_LOW (size_tree));
      else
        /* Leave space for it.  */
        assemble_zeros (TREE_INT_CST_LOW (size_tree));
    }

 finish:
#ifdef XCOFF_DEBUGGING_INFO
  /* Unfortunately, the IBM assembler cannot handle stabx before the actual
     declaration.  When something like ".stabx  "aa:S-2",aa,133,0" is emitted 
     and `aa' hasn't been output yet, the assembler generates a stab entry with
     a value of zero, in addition to creating an unnecessary external entry
     for `aa'.  Hence, we must postpone dbxout_symbol to here at the end.  */

  /* File-scope global variables are output here.  */
  if (write_symbols == XCOFF_DEBUG && top_level)
    {
      saved_in_section = in_section;

      dbxout_symbol (decl, 0);

      if (in_section != saved_in_section)
        variable_section (decl, reloc);
    }
#else
  /* There must be a statement after a label.  */
  ;
#endif
}

/* Return 1 if type TYPE contains any pointers.  */

static int
contains_pointers_p (type)
     tree type;
{
  switch (TREE_CODE (type))
    {
    case POINTER_TYPE:
    case REFERENCE_TYPE:
      /* I'm not sure whether OFFSET_TYPE needs this treatment,
         so I'll play safe and return 1.  */
    case OFFSET_TYPE:
      return 1;

    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      {
        tree fields;
        /* For a type that has fields, see if the fields have pointers.  */
        for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
          if (TREE_CODE (fields) == FIELD_DECL
              && contains_pointers_p (TREE_TYPE (fields)))
            return 1;
        return 0;
      }

    case ARRAY_TYPE:
      /* An array type contains pointers if its element type does.  */
      return contains_pointers_p (TREE_TYPE (type));

    default:
      return 0;
    }
}

/* Output something to declare an external symbol to the assembler.
   (Most assemblers don't need this, so we normally output nothing.)
   Do nothing if DECL is not external.  */

void
assemble_external (decl)
     tree decl ATTRIBUTE_UNUSED;
{
#ifdef ASM_OUTPUT_EXTERNAL
  if (TREE_CODE_CLASS (TREE_CODE (decl)) == 'd'
      && DECL_EXTERNAL (decl) && TREE_PUBLIC (decl))
    {
      rtx rtl = DECL_RTL (decl);

      if (GET_CODE (rtl) == MEM && GET_CODE (XEXP (rtl, 0)) == SYMBOL_REF
          && ! SYMBOL_REF_USED (XEXP (rtl, 0)))
        {
          /* Some systems do require some output.  */
          SYMBOL_REF_USED (XEXP (rtl, 0)) = 1;
          ASM_OUTPUT_EXTERNAL (asm_out_file, decl, XSTR (XEXP (rtl, 0), 0));
        }
    }
#endif
}

/* Similar, for calling a library function FUN.  */

void
assemble_external_libcall (fun)
     rtx fun ATTRIBUTE_UNUSED;
{
#ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  /* Declare library function name external when first used, if nec.  */
  if (! SYMBOL_REF_USED (fun))
    {
      SYMBOL_REF_USED (fun) = 1;
      ASM_OUTPUT_EXTERNAL_LIBCALL (asm_out_file, fun);
    }
#endif
}

/* Declare the label NAME global.  */

void
assemble_global (name)
     char *name;
{
  ASM_GLOBALIZE_LABEL (asm_out_file, name);
}

/* Assemble a label named NAME.  */

void
assemble_label (name)
     char *name;
{
  ASM_OUTPUT_LABEL (asm_out_file, name);
}

/* Output to FILE a reference to the assembler name of a C-level name NAME.
   If NAME starts with a *, the rest of NAME is output verbatim.
   Otherwise NAME is transformed in an implementation-defined way
   (usually by the addition of an underscore).
   Many macros in the tm file are defined to call this function.  */

void
assemble_name (file, name)
     FILE *file;
     const char *name;
{
  const char *real_name;
  tree id;

  STRIP_NAME_ENCODING (real_name, name);
  if (flag_prefix_function_name 
      && ! bcmp (real_name, CHKR_PREFIX, CHKR_PREFIX_SIZE))
    real_name = real_name + CHKR_PREFIX_SIZE;

  id = maybe_get_identifier (real_name);
  if (id)
    TREE_SYMBOL_REFERENCED (id) = 1;

  if (name[0] == '*')
    fputs (&name[1], file);
  else
    ASM_OUTPUT_LABELREF (file, name);
}

/* Allocate SIZE bytes writable static space with a gensym name
   and return an RTX to refer to its address.  */

rtx
assemble_static_space (size)
     int size;
{
  char name[12];
  char *namestring;
  rtx x;

#if 0
  if (flag_shared_data)
    data_section ();
#endif

  ASM_GENERATE_INTERNAL_LABEL (name, "LF", const_labelno);
  ++const_labelno;

  namestring = (char *) obstack_alloc (saveable_obstack,
                                       strlen (name) + 2);
  strcpy (namestring, name);

  x = gen_rtx_SYMBOL_REF (Pmode, namestring);

#ifdef ASM_OUTPUT_ALIGNED_DECL_LOCAL
  ASM_OUTPUT_ALIGNED_DECL_LOCAL (asm_out_file, NULL_TREE, name, size,
                                 BIGGEST_ALIGNMENT);
#else
#ifdef ASM_OUTPUT_ALIGNED_LOCAL
  ASM_OUTPUT_ALIGNED_LOCAL (asm_out_file, name, size, BIGGEST_ALIGNMENT);
#else
  {
    /* Round size up to multiple of BIGGEST_ALIGNMENT bits
       so that each uninitialized object starts on such a boundary.  */
    /* Variable `rounded' might or might not be used in ASM_OUTPUT_LOCAL. */
    int rounded ATTRIBUTE_UNUSED
      = ((size + (BIGGEST_ALIGNMENT / BITS_PER_UNIT) - 1)
         / (BIGGEST_ALIGNMENT / BITS_PER_UNIT)
         * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
    ASM_OUTPUT_LOCAL (asm_out_file, name, size, rounded);
  }
#endif
#endif
  return x;
}

/* Assemble the static constant template for function entry trampolines.
   This is done at most once per compilation.
   Returns an RTX for the address of the template.  */

#ifdef TRAMPOLINE_TEMPLATE
rtx
assemble_trampoline_template ()
{
  char label[256];
  char *name;
  int align;

  /* By default, put trampoline templates in read-only data section.  */

#ifdef TRAMPOLINE_SECTION
  TRAMPOLINE_SECTION ();
#else
  readonly_data_section ();
#endif

  /* Write the assembler code to define one.  */
  align = floor_log2 (TRAMPOLINE_ALIGNMENT / BITS_PER_UNIT);
  if (align > 0)
    ASM_OUTPUT_ALIGN (asm_out_file, align);

  ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LTRAMP", 0);
  TRAMPOLINE_TEMPLATE (asm_out_file);

  /* Record the rtl to refer to it.  */
  ASM_GENERATE_INTERNAL_LABEL (label, "LTRAMP", 0);
  name
    = (char *) obstack_copy0 (&permanent_obstack, label, strlen (label));
  return gen_rtx_SYMBOL_REF (Pmode, name);
}
#endif
\f
/* Assemble the integer constant X into an object of SIZE bytes.
   X must be either a CONST_INT or CONST_DOUBLE.

   Return 1 if we were able to output the constant, otherwise 0.  If FORCE is
   non-zero, abort if we can't output the constant.  */

int
assemble_integer (x, size, force)
     rtx x;
     int size;
     int force;
{
  /* First try to use the standard 1, 2, 4, 8, and 16 byte
     ASM_OUTPUT... macros.  */

  switch (size)
    {
#ifdef ASM_OUTPUT_CHAR
    case 1:
      ASM_OUTPUT_CHAR (asm_out_file, x);
      return 1;
#endif

#ifdef ASM_OUTPUT_SHORT
    case 2:
      ASM_OUTPUT_SHORT (asm_out_file, x);
      return 1;
#endif

#ifdef ASM_OUTPUT_INT
    case 4:
      ASM_OUTPUT_INT (asm_out_file, x);
      return 1;
#endif

#ifdef ASM_OUTPUT_DOUBLE_INT
    case 8:
      ASM_OUTPUT_DOUBLE_INT (asm_out_file, x);
      return 1;
#endif

#ifdef ASM_OUTPUT_QUADRUPLE_INT
    case 16:
      ASM_OUTPUT_QUADRUPLE_INT (asm_out_file, x);
      return 1;
#endif
    }

  /* If we couldn't do it that way, there are two other possibilities: First,
     if the machine can output an explicit byte and this is a 1 byte constant,
     we can use ASM_OUTPUT_BYTE.  */

#ifdef ASM_OUTPUT_BYTE
  if (size == 1 && GET_CODE (x) == CONST_INT)
    {
      ASM_OUTPUT_BYTE (asm_out_file, INTVAL (x));
      return 1;
    }
#endif

  /* Finally, if SIZE is larger than a single word, try to output the constant
     one word at a time.  */

  if (size > UNITS_PER_WORD)
    {
      int i;
      enum machine_mode mode
        = mode_for_size (size * BITS_PER_UNIT, MODE_INT, 0);
      rtx word;

      for (i = 0; i < size / UNITS_PER_WORD; i++)
        {
          word = operand_subword (x, i, 0, mode);

          if (word == 0)
            break;

          if (! assemble_integer (word, UNITS_PER_WORD, 0))
            break;
        }

      if (i == size / UNITS_PER_WORD)
        return 1;
      /* If we output at least one word and then could not finish,
         there is no valid way to continue.  */
      if (i > 0)
        abort ();
    }

  if (force)
    abort ();

  return 0;
}
\f
/* Assemble the floating-point constant D into an object of size MODE.  */

void
assemble_real (d, mode)
     REAL_VALUE_TYPE d;
     enum machine_mode mode;
{
  jmp_buf output_constant_handler;

  if (setjmp (output_constant_handler))
    {
      error ("floating point trap outputting a constant");
#ifdef REAL_IS_NOT_DOUBLE
      bzero ((char *) &d, sizeof d);
      d = dconst0;
#else
      d = 0;
#endif
    }

  set_float_handler (output_constant_handler);

  switch (mode)
    {
#ifdef ASM_OUTPUT_BYTE_FLOAT
    case QFmode:
      ASM_OUTPUT_BYTE_FLOAT (asm_out_file, d);
      break;
#endif
#ifdef ASM_OUTPUT_SHORT_FLOAT
    case HFmode:
      ASM_OUTPUT_SHORT_FLOAT (asm_out_file, d);
      break;
#endif
#ifdef ASM_OUTPUT_THREE_QUARTER_FLOAT
    case TQFmode:
      ASM_OUTPUT_THREE_QUARTER_FLOAT (asm_out_file, d);
      break;
#endif
#ifdef ASM_OUTPUT_FLOAT
    case SFmode:
      ASM_OUTPUT_FLOAT (asm_out_file, d);
      break;
#endif

#ifdef ASM_OUTPUT_DOUBLE
    case DFmode:
      ASM_OUTPUT_DOUBLE (asm_out_file, d);
      break;
#endif

#ifdef ASM_OUTPUT_LONG_DOUBLE
    case XFmode:
    case TFmode:
      ASM_OUTPUT_LONG_DOUBLE (asm_out_file, d);
      break;
#endif

    default:
      abort ();
    }

  set_float_handler (NULL_PTR);
}
\f
/* Here we combine duplicate floating constants to make
   CONST_DOUBLE rtx's, and force those out to memory when necessary.  */

/* Chain of all CONST_DOUBLE rtx's constructed for the current function.
   They are chained through the CONST_DOUBLE_CHAIN.
   A CONST_DOUBLE rtx has CONST_DOUBLE_MEM != cc0_rtx iff it is on this chain.
   In that case, CONST_DOUBLE_MEM is either a MEM,
   or const0_rtx if no MEM has been made for this CONST_DOUBLE yet.

   (CONST_DOUBLE_MEM is used only for top-level functions.
   See force_const_mem for explanation.)  */

static rtx const_double_chain;

/* Return a CONST_DOUBLE or CONST_INT for a value specified as a pair of ints.
   For an integer, I0 is the low-order word and I1 is the high-order word.
   For a real number, I0 is the word with the low address
   and I1 is the word with the high address.  */

rtx
immed_double_const (i0, i1, mode)
     HOST_WIDE_INT i0, i1;
     enum machine_mode mode;
{
  register rtx r;

  if (GET_MODE_CLASS (mode) == MODE_INT
      || GET_MODE_CLASS (mode) == MODE_PARTIAL_INT)
    {
      /* We clear out all bits that don't belong in MODE, unless they and our
         sign bit are all one.  So we get either a reasonable negative value
         or a reasonable unsigned value for this mode.  */
      int width = GET_MODE_BITSIZE (mode);
      if (width < HOST_BITS_PER_WIDE_INT
          && ((i0 & ((HOST_WIDE_INT) (-1) << (width - 1)))
              != ((HOST_WIDE_INT) (-1) << (width - 1))))
        i0 &= ((HOST_WIDE_INT) 1 << width) - 1, i1 = 0;
      else if (width == HOST_BITS_PER_WIDE_INT
               && ! (i1 == ~0 && i0 < 0))
        i1 = 0;
      else if (width > 2 * HOST_BITS_PER_WIDE_INT)
        /* We cannot represent this value as a constant.  */
        abort ();

      /* If this would be an entire word for the target, but is not for
         the host, then sign-extend on the host so that the number will look
         the same way on the host that it would on the target.

         For example, when building a 64 bit alpha hosted 32 bit sparc
         targeted compiler, then we want the 32 bit unsigned value -1 to be
         represented as a 64 bit value -1, and not as 0x00000000ffffffff.
         The later confuses the sparc backend.  */

      if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width
          && (i0 & ((HOST_WIDE_INT) 1 << (width - 1))))
        i0 |= ((HOST_WIDE_INT) (-1) << width);

      /* If MODE fits within HOST_BITS_PER_WIDE_INT, always use a CONST_INT.

         ??? Strictly speaking, this is wrong if we create a CONST_INT
         for a large unsigned constant with the size of MODE being
         HOST_BITS_PER_WIDE_INT and later try to interpret that constant in a
         wider mode.  In that case we will mis-interpret it as a negative
         number.

         Unfortunately, the only alternative is to make a CONST_DOUBLE
         for any constant in any mode if it is an unsigned constant larger
         than the maximum signed integer in an int on the host.  However,
         doing this will break everyone that always expects to see a CONST_INT
         for SImode and smaller.

         We have always been making CONST_INTs in this case, so nothing new
         is being broken.  */

      if (width <= HOST_BITS_PER_WIDE_INT)
        i1 = (i0 < 0) ? ~(HOST_WIDE_INT) 0 : 0;

      /* If this integer fits in one word, return a CONST_INT.  */
      if ((i1 == 0 && i0 >= 0)
          || (i1 == ~0 && i0 < 0))
        return GEN_INT (i0);

      /* We use VOIDmode for integers.  */
      mode = VOIDmode;
    }

  /* Search the chain for an existing CONST_DOUBLE with the right value.
     If one is found, return it.  */

  for (r = const_double_chain; r; r = CONST_DOUBLE_CHAIN (r))
    if (CONST_DOUBLE_LOW (r) == i0 && CONST_DOUBLE_HIGH (r) == i1
        && GET_MODE (r) == mode)
      return r;

  /* No; make a new one and add it to the chain.

     We may be called by an optimizer which may be discarding any memory
     allocated during its processing (such as combine and loop).  However,
     we will be leaving this constant on the chain, so we cannot tolerate
     freed memory.  So switch to saveable_obstack for this allocation
     and then switch back if we were in current_obstack.  */

  push_obstacks_nochange ();
  rtl_in_saveable_obstack ();
  r = gen_rtx_CONST_DOUBLE (mode, NULL_RTX, i0, i1);
  pop_obstacks ();

  /* Don't touch const_double_chain in nested function; see force_const_mem.
     Also, don't touch it if not inside any function.  */
  if (outer_function_chain == 0 && current_function_decl != 0)
    {
      CONST_DOUBLE_CHAIN (r) = const_double_chain;
      const_double_chain = r;
    }

  /* Store const0_rtx in mem-slot since this CONST_DOUBLE is on the chain.
     Actual use of mem-slot is only through force_const_mem.  */

  CONST_DOUBLE_MEM (r) = const0_rtx;

  return r;
}

/* Return a CONST_DOUBLE for a specified `double' value
   and machine mode.  */

rtx
immed_real_const_1 (d, mode)
     REAL_VALUE_TYPE d;
     enum machine_mode mode;
{
  union real_extract u;
  register rtx r;

  /* Get the desired `double' value as a sequence of ints
     since that is how they are stored in a CONST_DOUBLE.  */

  u.d = d;

  /* Detect special cases.  */

  if (REAL_VALUES_IDENTICAL (dconst0, d))
    return CONST0_RTX (mode);
  /* Check for NaN first, because some ports (specifically the i386) do not
     emit correct ieee-fp code by default, and thus will generate a core
     dump here if we pass a NaN to REAL_VALUES_EQUAL and if REAL_VALUES_EQUAL
     does a floating point comparison.  */
  else if (! REAL_VALUE_ISNAN (d) && REAL_VALUES_EQUAL (dconst1, d))
    return CONST1_RTX (mode);

  if (sizeof u == sizeof (HOST_WIDE_INT))
    return immed_double_const (u.i[0], 0, mode);
  if (sizeof u == 2 * sizeof (HOST_WIDE_INT))
    return immed_double_const (u.i[0], u.i[1], mode);

  /* The rest of this function handles the case where
     a float value requires more than 2 ints of space.
     It will be deleted as dead code on machines that don't need it.  */

  /* Search the chain for an existing CONST_DOUBLE with the right value.
     If one is found, return it.  */

  for (r = const_double_chain; r; r = CONST_DOUBLE_CHAIN (r))
    if (! bcmp ((char *) &CONST_DOUBLE_LOW (r), (char *) &u, sizeof u)
        && GET_MODE (r) == mode)
      return r;

  /* No; make a new one and add it to the chain.

     We may be called by an optimizer which may be discarding any memory
     allocated during its processing (such as combine and loop).  However,
     we will be leaving this constant on the chain, so we cannot tolerate
     freed memory.  So switch to saveable_obstack for this allocation
     and then switch back if we were in current_obstack.  */

  push_obstacks_nochange ();
  rtl_in_saveable_obstack ();
  r = rtx_alloc (CONST_DOUBLE);
  PUT_MODE (r, mode);
  bcopy ((char *) &u, (char *) &CONST_DOUBLE_LOW (r), sizeof u);
  pop_obstacks ();

  /* Don't touch const_double_chain in nested function; see force_const_mem.
     Also, don't touch it if not inside any function.  */
  if (outer_function_chain == 0 && current_function_decl != 0)
    {
      CONST_DOUBLE_CHAIN (r) = const_double_chain;
      const_double_chain = r;
    }

  /* Store const0_rtx in CONST_DOUBLE_MEM since this CONST_DOUBLE is on the
     chain, but has not been allocated memory.  Actual use of CONST_DOUBLE_MEM
     is only through force_const_mem.  */

  CONST_DOUBLE_MEM (r) = const0_rtx;

  return r;
}

/* Return a CONST_DOUBLE rtx for a value specified by EXP,
   which must be a REAL_CST tree node.  */

rtx
immed_real_const (exp)
     tree exp;
{
  return immed_real_const_1 (TREE_REAL_CST (exp), TYPE_MODE (TREE_TYPE (exp)));
}

/* At the end of a function, forget the memory-constants
   previously made for CONST_DOUBLEs.  Mark them as not on real_constant_chain.
   Also clear out real_constant_chain and clear out all the chain-pointers.  */

void
clear_const_double_mem ()
{
  register rtx r, next;

  /* Don't touch CONST_DOUBLE_MEM for nested functions.
     See force_const_mem for explanation.  */
  if (outer_function_chain != 0)
    return;

  for (r = const_double_chain; r; r = next)
    {
      next = CONST_DOUBLE_CHAIN (r);
      CONST_DOUBLE_CHAIN (r) = 0;
      CONST_DOUBLE_MEM (r) = cc0_rtx;
    }
  const_double_chain = 0;
}
\f
/* Given an expression EXP with a constant value,
   reduce it to the sum of an assembler symbol and an integer.
   Store them both in the structure *VALUE.
   Abort if EXP does not reduce.  */

struct addr_const
{
  rtx base;
  HOST_WIDE_INT offset;
};

static void
decode_addr_const (exp, value)
     tree exp;
     struct addr_const *value;
{
  register tree target = TREE_OPERAND (exp, 0);
  register int offset = 0;
  register rtx x;

  while (1)
    {
      if (TREE_CODE (target) == COMPONENT_REF
          && (TREE_CODE (DECL_FIELD_BITPOS (TREE_OPERAND (target, 1)))
              == INTEGER_CST))
        {
          offset += TREE_INT_CST_LOW (DECL_FIELD_BITPOS (TREE_OPERAND (target, 1))) / BITS_PER_UNIT;
          target = TREE_OPERAND (target, 0);
        }
      else if (TREE_CODE (target) == ARRAY_REF)
        {
          if (TREE_CODE (TREE_OPERAND (target, 1)) != INTEGER_CST
              || TREE_CODE (TYPE_SIZE (TREE_TYPE (target))) != INTEGER_CST)
            abort ();
          offset += ((TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (target)))
                      * TREE_INT_CST_LOW (TREE_OPERAND (target, 1)))
                     / BITS_PER_UNIT);
          target = TREE_OPERAND (target, 0);
        }
      else
        break;
    }

  switch (TREE_CODE (target))
    {
    case VAR_DECL:
    case FUNCTION_DECL:
      x = DECL_RTL (target);
      break;

    case LABEL_DECL:
      x = gen_rtx_MEM (FUNCTION_MODE,
                       gen_rtx_LABEL_REF (VOIDmode,
                                          label_rtx (TREE_OPERAND (exp, 0))));
      break;

    case REAL_CST:
    case STRING_CST:
    case COMPLEX_CST:
    case CONSTRUCTOR:
    case INTEGER_CST:
      x = TREE_CST_RTL (target);
      break;

    default:
      abort ();
    }

  if (GET_CODE (x) != MEM)
    abort ();
  x = XEXP (x, 0);

  value->base = x;
  value->offset = offset;
}
\f
/* Uniquize all constants that appear in memory.
   Each constant in memory thus far output is recorded
   in `const_hash_table' with a `struct constant_descriptor'
   that contains a polish representation of the value of
   the constant.

   We cannot store the trees in the hash table
   because the trees may be temporary.  */

struct constant_descriptor
{
  struct constant_descriptor *next;
  char *label;
  char contents[1];
};

#define HASHBITS 30
#define MAX_HASH_TABLE 1009
static struct constant_descriptor *const_hash_table[MAX_HASH_TABLE];

/* Compute a hash code for a constant expression.  */

static int
const_hash (exp)
     tree exp;
{
  register char *p;
  register int len, hi, i;
  register enum tree_code code = TREE_CODE (exp);

  /* Either set P and LEN to the address and len of something to hash and
     exit the switch or return a value.  */

  switch (code)
    {
    case INTEGER_CST:
      p = (char *) &TREE_INT_CST_LOW (exp);
      len = 2 * sizeof TREE_INT_CST_LOW (exp);
      break;

    case REAL_CST:
      p = (char *) &TREE_REAL_CST (exp);
      len = sizeof TREE_REAL_CST (exp);
      break;

    case STRING_CST:
      p = TREE_STRING_POINTER (exp);
      len = TREE_STRING_LENGTH (exp);
      break;

    case COMPLEX_CST:
      return (const_hash (TREE_REALPART (exp)) * 5
              + const_hash (TREE_IMAGPART (exp)));

    case CONSTRUCTOR:
      if (TREE_CODE (TREE_TYPE (exp)) == SET_TYPE)
        {
          len = int_size_in_bytes (TREE_TYPE (exp));
          p = (char *) alloca (len);
          get_set_constructor_bytes (exp, (unsigned char *) p, len);
          break;
        }
      else
        {
          register tree link;

          /* For record type, include the type in the hashing.
             We do not do so for array types
             because (1) the sizes of the elements are sufficient
             and (2) distinct array types can have the same constructor.
             Instead, we include the array size because the constructor could
             be shorter.  */
          if (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE)
            hi = ((unsigned long) TREE_TYPE (exp) & ((1 << HASHBITS) - 1))
              % MAX_HASH_TABLE;
          else
            hi = ((5 + int_size_in_bytes (TREE_TYPE (exp)))
                  & ((1 << HASHBITS) - 1)) % MAX_HASH_TABLE;

          for (link = CONSTRUCTOR_ELTS (exp); link; link = TREE_CHAIN (link))
            if (TREE_VALUE (link))
              hi
                = (hi * 603 + const_hash (TREE_VALUE (link))) % MAX_HASH_TABLE;

          return hi;
        }

    case ADDR_EXPR:
      {
        struct addr_const value;

        decode_addr_const (exp, &value);
        if (GET_CODE (value.base) == SYMBOL_REF)
          {
            /* Don't hash the address of the SYMBOL_REF;
               only use the offset and the symbol name.  */
            hi = value.offset;
            p = XSTR (value.base, 0);
            for (i = 0; p[i] != 0; i++)
              hi = ((hi * 613) + (unsigned) (p[i]));
          }
        else if (GET_CODE (value.base) == LABEL_REF)
          hi = value.offset + CODE_LABEL_NUMBER (XEXP (value.base, 0)) * 13;
        else
          abort();

        hi &= (1 << HASHBITS) - 1;
        hi %= MAX_HASH_TABLE;
      }
      return hi;

    case PLUS_EXPR:
    case MINUS_EXPR:
      return (const_hash (TREE_OPERAND (exp, 0)) * 9
              + const_hash (TREE_OPERAND (exp, 1)));

    case NOP_EXPR:
    case CONVERT_EXPR:
    case NON_LVALUE_EXPR:
      return const_hash (TREE_OPERAND (exp, 0)) * 7 + 2;
      
    default:
      abort ();
    }

  /* Compute hashing function */
  hi = len;
  for (i = 0; i < len; i++)
    hi = ((hi * 613) + (unsigned) (p[i]));

  hi &= (1 << HASHBITS) - 1;
  hi %= MAX_HASH_TABLE;
  return hi;
}
\f
/* Compare a constant expression EXP with a constant-descriptor DESC.
   Return 1 if DESC describes a constant with the same value as EXP.  */

static int
compare_constant (exp, desc)
     tree exp;
     struct constant_descriptor *desc;
{
  return 0 != compare_constant_1 (exp, desc->contents);
}

/* Compare constant expression EXP with a substring P of a constant descriptor.
   If they match, return a pointer to the end of the substring matched.
   If they do not match, return 0.

   Since descriptors are written in polish prefix notation,
   this function can be used recursively to test one operand of EXP
   against a subdescriptor, and if it succeeds it returns the
   address of the subdescriptor for the next operand.  */

static char *
compare_constant_1 (exp, p)
     tree exp;
     char *p;
{
  register char *strp;
  register int len;
  register enum tree_code code = TREE_CODE (exp);

  if (code != (enum tree_code) *p++)
    return 0;

  /* Either set STRP, P and LEN to pointers and length to compare and exit the
     switch, or return the result of the comparison.  */

  switch (code)
    {
    case INTEGER_CST:
      /* Integer constants are the same only if the same width of type.  */
      if (*p++ != TYPE_PRECISION (TREE_TYPE (exp)))
        return 0;

      strp = (char *) &TREE_INT_CST_LOW (exp);
      len = 2 * sizeof TREE_INT_CST_LOW (exp);
      break;

    case REAL_CST:
      /* Real constants are the same only if the same width of type.  */
      if (*p++ != TYPE_PRECISION (TREE_TYPE (exp)))
        return 0;

      strp = (char *) &TREE_REAL_CST (exp);
      len = sizeof TREE_REAL_CST (exp);
      break;

    case STRING_CST:
      if (flag_writable_strings)
        return 0;

      if (*p++ != TYPE_MODE (TREE_TYPE (exp)))
        return 0;

      strp = TREE_STRING_POINTER (exp);
      len = TREE_STRING_LENGTH (exp);
      if (bcmp ((char *) &TREE_STRING_LENGTH (exp), p,
                sizeof TREE_STRING_LENGTH (exp)))
        return 0;

      p += sizeof TREE_STRING_LENGTH (exp);
      break;

    case COMPLEX_CST:
      p = compare_constant_1 (TREE_REALPART (exp), p);
      if (p == 0)
        return 0;

      return compare_constant_1 (TREE_IMAGPART (exp), p);

    case CONSTRUCTOR:
      if (TREE_CODE (TREE_TYPE (exp)) == SET_TYPE)
        {
          int xlen = len = int_size_in_bytes (TREE_TYPE (exp));

          strp = (char *) alloca (len);
          get_set_constructor_bytes (exp, (unsigned char *) strp, len);
          if (bcmp ((char *) &xlen, p, sizeof xlen))
            return 0;

          p += sizeof xlen;
          break;
        }
      else
        {
          register tree link;
          int length = list_length (CONSTRUCTOR_ELTS (exp));
          tree type;
          int have_purpose = 0;

          for (link = CONSTRUCTOR_ELTS (exp); link; link = TREE_CHAIN (link))
            if (TREE_PURPOSE (link))
              have_purpose = 1;

          if (bcmp ((char *) &length, p, sizeof length))
            return 0;

          p += sizeof length;

          /* For record constructors, insist that the types match.
             For arrays, just verify both constructors are for arrays. 
             Then insist that either both or none have any TREE_PURPOSE
             values.  */
          if (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE)
            type = TREE_TYPE (exp);
          else
            type = 0;

          if (bcmp ((char *) &type, p, sizeof type))
            return 0;

          p += sizeof type;

          if (bcmp ((char *) &have_purpose, p, sizeof have_purpose))
            return 0;

          p += sizeof have_purpose;

          /* For arrays, insist that the size in bytes match.  */
          if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE)
            {
              HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (exp));

              if (bcmp ((char *) &size, p, sizeof size))
                return 0;

              p += sizeof size;
            }

          for (link = CONSTRUCTOR_ELTS (exp); link; link = TREE_CHAIN (link))
            {
              if (TREE_VALUE (link))
                {
                  if ((p = compare_constant_1 (TREE_VALUE (link), p)) == 0)
                    return 0;
                }
              else
                {
                  tree zero = 0;

                  if (bcmp ((char *) &zero, p, sizeof zero))
                    return 0;

                  p += sizeof zero;
                }

              if (TREE_PURPOSE (link)
                  && TREE_CODE (TREE_PURPOSE (link)) == FIELD_DECL)
                {
                  if (bcmp ((char *) &TREE_PURPOSE (link), p,
                            sizeof TREE_PURPOSE (link)))
                    return 0;

                  p += sizeof TREE_PURPOSE (link);
                }
              else if (TREE_PURPOSE (link))
                {
                  if ((p = compare_constant_1 (TREE_PURPOSE (link), p)) == 0)
                    return 0;
                }
              else if (have_purpose)
                {
                  int zero = 0;

                  if (bcmp ((char *) &zero, p, sizeof zero))
                    return 0;

                  p += sizeof zero;
                }
            }

          return p;
        }

    case ADDR_EXPR:
      {
        struct addr_const value;

        decode_addr_const (exp, &value);
        strp = (char *) &value.offset;
        len = sizeof value.offset;
        /* Compare the offset.  */
        while (--len >= 0)
          if (*p++ != *strp++)
            return 0;

        /* Compare symbol name.  */
        strp = XSTR (value.base, 0);
        len = strlen (strp) + 1;
      }
      break;

    case PLUS_EXPR:
    case MINUS_EXPR:
    case RANGE_EXPR:
      p = compare_constant_1 (TREE_OPERAND (exp, 0), p);
      if (p == 0)
        return 0;

      return compare_constant_1 (TREE_OPERAND (exp, 1), p);

    case NOP_EXPR:
    case CONVERT_EXPR:
    case NON_LVALUE_EXPR:
      return compare_constant_1 (TREE_OPERAND (exp, 0), p);

    default:
      abort ();
    }

  /* Compare constant contents.  */
  while (--len >= 0)
    if (*p++ != *strp++)
      return 0;

  return p;
}
\f
/* Construct a constant descriptor for the expression EXP.
   It is up to the caller to enter the descriptor in the hash table.  */

static struct constant_descriptor *
record_constant (exp)
     tree exp;
{
  struct constant_descriptor *next = 0;
  char *label = 0;

  /* Make a struct constant_descriptor.  The first two pointers will
     be filled in later.  Here we just leave space for them.  */

  obstack_grow (&permanent_obstack, (char *) &next, sizeof next);
  obstack_grow (&permanent_obstack, (char *) &label, sizeof label);
  record_constant_1 (exp);
  return (struct constant_descriptor *) obstack_finish (&permanent_obstack);
}

/* Add a description of constant expression EXP
   to the object growing in `permanent_obstack'.
   No need to return its address; the caller will get that
   from the obstack when the object is complete.  */

static void
record_constant_1 (exp)
     tree exp;
{
  register char *strp;
  register int len;
  register enum tree_code code = TREE_CODE (exp);

  obstack_1grow (&permanent_obstack, (unsigned int) code);

  switch (code)
    {
    case INTEGER_CST:
      obstack_1grow (&permanent_obstack, TYPE_PRECISION (TREE_TYPE (exp)));
      strp = (char *) &TREE_INT_CST_LOW (exp);
      len = 2 * sizeof TREE_INT_CST_LOW (exp);
      break;

    case REAL_CST:
      obstack_1grow (&permanent_obstack, TYPE_PRECISION (TREE_TYPE (exp)));
      strp = (char *) &TREE_REAL_CST (exp);
      len = sizeof TREE_REAL_CST (exp);
      break;

    case STRING_CST:
      if (flag_writable_strings)
        return;

      obstack_1grow (&permanent_obstack, TYPE_MODE (TREE_TYPE (exp)));
      strp = TREE_STRING_POINTER (exp);
      len = TREE_STRING_LENGTH (exp);
      obstack_grow (&permanent_obstack, (char *) &TREE_STRING_LENGTH (exp),
                    sizeof TREE_STRING_LENGTH (exp));
      break;

    case COMPLEX_CST:
      record_constant_1 (TREE_REALPART (exp));
      record_constant_1 (TREE_IMAGPART (exp));
      return;

    case CONSTRUCTOR:
      if (TREE_CODE (TREE_TYPE (exp)) == SET_TYPE)
        {
          int nbytes = int_size_in_bytes (TREE_TYPE (exp));
          obstack_grow (&permanent_obstack, &nbytes, sizeof (nbytes));
          obstack_blank (&permanent_obstack, nbytes);
          get_set_constructor_bytes
            (exp, (unsigned char *) permanent_obstack.next_free-nbytes,
             nbytes);
          return;
        }
      else
        {
          register tree link;
          int length = list_length (CONSTRUCTOR_ELTS (exp));
          tree type;
          int have_purpose = 0;

          for (link = CONSTRUCTOR_ELTS (exp); link; link = TREE_CHAIN (link))
            if (TREE_PURPOSE (link))
              have_purpose = 1;

          obstack_grow (&permanent_obstack, (char *) &length, sizeof length);

          /* For record constructors, insist that the types match.
             For arrays, just verify both constructors are for arrays. 
             Then insist that either both or none have any TREE_PURPOSE
             values.  */
          if (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE)
            type = TREE_TYPE (exp);
          else
            type = 0;
          obstack_grow (&permanent_obstack, (char *) &type, sizeof type);
          obstack_grow (&permanent_obstack, (char *) &have_purpose,
                        sizeof have_purpose);

          /* For arrays, insist that the size in bytes match.  */
          if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE)
            {
              HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (exp));
              obstack_grow (&permanent_obstack, (char *) &size, sizeof size);
            }

          for (link = CONSTRUCTOR_ELTS (exp); link; link = TREE_CHAIN (link))
            {
              if (TREE_VALUE (link))
                record_constant_1 (TREE_VALUE (link));
              else
                {
                  tree zero = 0;

                  obstack_grow (&permanent_obstack,
                                (char *) &zero, sizeof zero);
                }

              if (TREE_PURPOSE (link)
                  && TREE_CODE (TREE_PURPOSE (link)) == FIELD_DECL)
                obstack_grow (&permanent_obstack,
                              (char *) &TREE_PURPOSE (link),
                              sizeof TREE_PURPOSE (link));
              else if (TREE_PURPOSE (link))
                record_constant_1 (TREE_PURPOSE (link));
              else if (have_purpose)
                {
                  int zero = 0;

                  obstack_grow (&permanent_obstack,
                                (char *) &zero, sizeof zero);
                }
            }
        }
      return;

    case ADDR_EXPR:
      {
        struct addr_const value;

        decode_addr_const (exp, &value);
        /* Record the offset.  */
        obstack_grow (&permanent_obstack,
                      (char *) &value.offset, sizeof value.offset);
        /* Record the symbol name.  */
        obstack_grow (&permanent_obstack, XSTR (value.base, 0),
                      strlen (XSTR (value.base, 0)) + 1);
      }
      return;

    case PLUS_EXPR:
    case MINUS_EXPR:
    case RANGE_EXPR:
      record_constant_1 (TREE_OPERAND (exp, 0));
      record_constant_1 (TREE_OPERAND (exp, 1));
      return;

    case NOP_EXPR:
    case CONVERT_EXPR:
    case NON_LVALUE_EXPR:
      record_constant_1 (TREE_OPERAND (exp, 0));
      return;

    default:
      abort ();
    }

  /* Record constant contents.  */
  obstack_grow (&permanent_obstack, strp, len);
}
\f
/* Record a list of constant expressions that were passed to
   output_constant_def but that could not be output right away.  */

struct deferred_constant
{
  struct deferred_constant *next;
  tree exp;
  int reloc;
  int labelno;
};

static struct deferred_constant *deferred_constants;

/* Another list of constants which should be output after the
   function.  */
static struct deferred_constant *after_function_constants;

/* Nonzero means defer output of addressed subconstants
   (i.e., those for which output_constant_def is called.)  */
static int defer_addressed_constants_flag;

/* Start deferring output of subconstants.  */

void
defer_addressed_constants ()
{
  defer_addressed_constants_flag++;
}

/* Stop deferring output of subconstants,
   and output now all those that have been deferred.  */

void
output_deferred_addressed_constants ()
{
  struct deferred_constant *p, *next;

  defer_addressed_constants_flag--;

  if (defer_addressed_constants_flag > 0)
    return;

  for (p = deferred_constants; p; p = next)
    {
      output_constant_def_contents (p->exp, p->reloc, p->labelno);
      next = p->next;
      free (p);
    }

  deferred_constants = 0;
}

/* Output any constants which should appear after a function.  */

static void
output_after_function_constants ()
{
  struct deferred_constant *p, *next;

  for (p = after_function_constants; p; p = next)
    {
      output_constant_def_contents (p->exp, p->reloc, p->labelno);
      next = p->next;
      free (p);
    }

  after_function_constants = 0;
}

/* Make a copy of the whole tree structure for a constant.
   This handles the same types of nodes that compare_constant
   and record_constant handle.  */

static tree
copy_constant (exp)
     tree exp;
{
  switch (TREE_CODE (exp))
    {
    case ADDR_EXPR:
      /* For ADDR_EXPR, we do not want to copy the decl whose address
         is requested.  We do want to copy constants though.  */
      if (TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (exp, 0))) == 'c')
        return build1 (TREE_CODE (exp), TREE_TYPE (exp),
                       copy_constant (TREE_OPERAND (exp, 0)));
      else
        return copy_node (exp);

    case INTEGER_CST:
    case REAL_CST:
    case STRING_CST:
      return copy_node (exp);

    case COMPLEX_CST:
      return build_complex (TREE_TYPE (exp),
                            copy_constant (TREE_REALPART (exp)),
                            copy_constant (TREE_IMAGPART (exp)));

    case PLUS_EXPR:
    case MINUS_EXPR:
      return build (TREE_CODE (exp), TREE_TYPE (exp),
                    copy_constant (TREE_OPERAND (exp, 0)),
                    copy_constant (TREE_OPERAND (exp, 1)));

    case NOP_EXPR:
    case CONVERT_EXPR:
    case NON_LVALUE_EXPR:
      return build1 (TREE_CODE (exp), TREE_TYPE (exp),
                     copy_constant (TREE_OPERAND (exp, 0)));

    case CONSTRUCTOR:
      {
        tree copy = copy_node (exp);
        tree list = copy_list (CONSTRUCTOR_ELTS (exp));
        tree tail;

        CONSTRUCTOR_ELTS (copy) = list;
        for (tail = list; tail; tail = TREE_CHAIN (tail))
          TREE_VALUE (tail) = copy_constant (TREE_VALUE (tail));
        if (TREE_CODE (TREE_TYPE (exp)) == SET_TYPE)
          for (tail = list; tail; tail = TREE_CHAIN (tail))
            TREE_PURPOSE (tail) = copy_constant (TREE_PURPOSE (tail));

        return copy;
      }

    default:
      abort ();
    }
}
\f
/* Return an rtx representing a reference to constant data in memory
   for the constant expression EXP.

   If assembler code for such a constant has already been output,
   return an rtx to refer to it.
   Otherwise, output such a constant in memory (or defer it for later)
   and generate an rtx for it.

   The TREE_CST_RTL of EXP is set up to point to that rtx.
   The const_hash_table records which constants already have label strings.  */

rtx
output_constant_def (exp)
     tree exp;
{
  register int hash;
  register struct constant_descriptor *desc;
  char label[256];
  char *found = 0;
  int reloc;
  register rtx def;

  if (TREE_CST_RTL (exp))
    return TREE_CST_RTL (exp);

  /* Make sure any other constants whose addresses appear in EXP
     are assigned label numbers.  */

  reloc = output_addressed_constants (exp);

  /* Compute hash code of EXP.  Search the descriptors for that hash code
     to see if any of them describes EXP.  If yes, the descriptor records
     the label number already assigned.  */

  hash = const_hash (exp) % MAX_HASH_TABLE;
      
  for (desc = const_hash_table[hash]; desc; desc = desc->next)
    if (compare_constant (exp, desc))
      {
        found = desc->label;
        break;
      }
      
  if (found == 0)
    {
      /* No constant equal to EXP is known to have been output.
         Make a constant descriptor to enter EXP in the hash table.
         Assign the label number and record it in the descriptor for
         future calls to this function to find.  */
          
      /* Create a string containing the label name, in LABEL.  */
      ASM_GENERATE_INTERNAL_LABEL (label, "LC", const_labelno);

      desc = record_constant (exp);
      desc->next = const_hash_table[hash];
      desc->label
        = (char *) obstack_copy0 (&permanent_obstack, label, strlen (label));
      const_hash_table[hash] = desc;
    }
  else
    {
      /* Create a string containing the label name, in LABEL.  */
      ASM_GENERATE_INTERNAL_LABEL (label, "LC", const_labelno);
    }
  
  /* We have a symbol name; construct the SYMBOL_REF and the MEM.  */

  push_obstacks_nochange ();
  if (TREE_PERMANENT (exp))
    end_temporary_allocation ();

  def = gen_rtx_SYMBOL_REF (Pmode, desc->label);
      
  TREE_CST_RTL (exp)
    = gen_rtx_MEM (TYPE_MODE (TREE_TYPE (exp)), def);
  RTX_UNCHANGING_P (TREE_CST_RTL (exp)) = 1;
  if (AGGREGATE_TYPE_P (TREE_TYPE (exp)))
    MEM_SET_IN_STRUCT_P (TREE_CST_RTL (exp), 1);

  pop_obstacks ();

  /* Optionally set flags or add text to the name to record information
     such as that it is a function name.  If the name is changed, the macro
     ASM_OUTPUT_LABELREF will have to know how to strip this information.  */
#ifdef ENCODE_SECTION_INFO
  ENCODE_SECTION_INFO (exp);
#endif

  /* If this is the first time we've seen this particular constant,
     output it (or defer its output for later).  */
  if (found == 0)
    {
      int after_function = 0;

#ifdef CONSTANT_AFTER_FUNCTION_P
      if (current_function_decl != 0
          && CONSTANT_AFTER_FUNCTION_P (exp))
        after_function = 1;
#endif

      if (defer_addressed_constants_flag || after_function)
        {
          struct deferred_constant *p;
          p = (struct deferred_constant *) xmalloc (sizeof (struct deferred_constant));

          push_obstacks_nochange ();
          suspend_momentary ();
          p->exp = copy_constant (exp);
          pop_obstacks ();
          p->reloc = reloc;
          p->labelno = const_labelno++;
          if (after_function)
            {
              p->next = after_function_constants;
              after_function_constants = p;
            }
          else
            {
              p->next = deferred_constants;
              deferred_constants = p;
            }
        }
      else
        {
          /* Do no output if -fsyntax-only.  */
          if (! flag_syntax_only)
            output_constant_def_contents (exp, reloc, const_labelno);
          ++const_labelno;
        }
    }

  return TREE_CST_RTL (exp);
}

/* Now output assembler code to define the label for EXP,
   and follow it with the data of EXP.  */

static void
output_constant_def_contents (exp, reloc, labelno)
     tree exp;
     int reloc;
     int labelno;
{
  int align;

  if (IN_NAMED_SECTION (exp))
    named_section (exp, NULL, reloc);
  else
    {
      /* First switch to text section, except for writable strings.  */
#ifdef SELECT_SECTION
      SELECT_SECTION (exp, reloc);
#else
      if (((TREE_CODE (exp) == STRING_CST) && flag_writable_strings)
          || (flag_pic && reloc))
        data_section ();
      else
        readonly_data_section ();
#endif
    }

  /* Align the location counter as required by EXP's data type.  */
  align = TYPE_ALIGN (TREE_TYPE (exp));
#ifdef CONSTANT_ALIGNMENT
  align = CONSTANT_ALIGNMENT (exp, align);
#endif

  if (align > BITS_PER_UNIT)
    ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT));

  /* Output the label itself.  */
  ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LC", labelno);

  /* Output the value of EXP.  */
  output_constant (exp,
                   (TREE_CODE (exp) == STRING_CST
                    ? TREE_STRING_LENGTH (exp)
                    : int_size_in_bytes (TREE_TYPE (exp))));

}
\f
/* Similar hash facility for making memory-constants
   from constant rtl-expressions.  It is used on RISC machines
   where immediate integer arguments and constant addresses are restricted
   so that such constants must be stored in memory.

   This pool of constants is reinitialized for each function
   so each function gets its own constants-pool that comes right before it.

   All structures allocated here are discarded when functions are saved for
   inlining, so they do not need to be allocated permanently.  */

#define MAX_RTX_HASH_TABLE 61
static struct constant_descriptor **const_rtx_hash_table;

/* Structure to represent sufficient information about a constant so that
   it can be output when the constant pool is output, so that function
   integration can be done, and to simplify handling on machines that reference
   constant pool as base+displacement.  */

struct pool_constant
{
  struct constant_descriptor *desc;
  struct pool_constant *next;
  enum machine_mode mode;
  rtx constant;
  int labelno;
  int align;
  int offset;
  int mark;
};

/* Pointers to first and last constant in pool.  */

static struct pool_constant *first_pool, *last_pool;

/* Current offset in constant pool (does not include any machine-specific
   header.  */

static int pool_offset;

/* Structure used to maintain hash table mapping symbols used to their
   corresponding constants.  */

struct pool_sym
{
  char *label;
  struct pool_constant *pool;
  struct pool_sym *next;
};

static struct pool_sym **const_rtx_sym_hash_table;

/* Hash code for a SYMBOL_REF with CONSTANT_POOL_ADDRESS_P true.
   The argument is XSTR (... , 0)  */

#define SYMHASH(LABEL)  \
  ((((unsigned long) (LABEL)) & ((1 << HASHBITS) - 1))  % MAX_RTX_HASH_TABLE)
\f
/* Initialize constant pool hashing for next function.  */

void
init_const_rtx_hash_table ()
{
  const_rtx_hash_table
    = ((struct constant_descriptor **)
       oballoc (MAX_RTX_HASH_TABLE * sizeof (struct constant_descriptor *)));
  const_rtx_sym_hash_table
    = ((struct pool_sym **)
       oballoc (MAX_RTX_HASH_TABLE * sizeof (struct pool_sym *)));
  bzero ((char *) const_rtx_hash_table,
         MAX_RTX_HASH_TABLE * sizeof (struct constant_descriptor *));
  bzero ((char *) const_rtx_sym_hash_table,
         MAX_RTX_HASH_TABLE * sizeof (struct pool_sym *));

  first_pool = last_pool = 0;
  pool_offset = 0;
}

/* Save and restore status for a nested function.  */

void
save_varasm_status (p, context)
     struct function *p;
     tree context;
{
  p->const_rtx_hash_table = const_rtx_hash_table;
  p->const_rtx_sym_hash_table = const_rtx_sym_hash_table;
  p->first_pool = first_pool;
  p->last_pool = last_pool;
  p->pool_offset = pool_offset;
  p->const_double_chain = const_double_chain;

  /* If we are pushing to toplevel, we can't reuse const_double_chain.  */
  if (context == NULL_TREE)
    const_double_chain = 0;
}

void
restore_varasm_status (p)
     struct function *p;
{
  const_rtx_hash_table = p->const_rtx_hash_table;
  const_rtx_sym_hash_table = p->const_rtx_sym_hash_table;
  first_pool = p->first_pool;
  last_pool = p->last_pool;
  pool_offset = p->pool_offset;
  const_double_chain = p->const_double_chain;
}
\f
enum kind { RTX_DOUBLE, RTX_INT };

struct rtx_const
{
#ifdef ONLY_INT_FIELDS
  unsigned int kind : 16;
  unsigned int mode : 16;
#else
  enum kind kind : 16;
  enum machine_mode mode : 16;
#endif
  union {
    union real_extract du;
    struct addr_const addr;
    struct {HOST_WIDE_INT high, low;} di;
  } un;
};

/* Express an rtx for a constant integer (perhaps symbolic)
   as the sum of a symbol or label plus an explicit integer.
   They are stored into VALUE.  */

static void
decode_rtx_const (mode, x, value)
     enum machine_mode mode;
     rtx x;
     struct rtx_const *value;
{
  /* Clear the whole structure, including any gaps.  */

  {
    int *p = (int *) value;
    int *end = (int *) (value + 1);
    while (p < end)
      *p++ = 0;
  }

  value->kind = RTX_INT;        /* Most usual kind.  */
  value->mode = mode;

  switch (GET_CODE (x))
    {
    case CONST_DOUBLE:
      value->kind = RTX_DOUBLE;
      if (GET_MODE (x) != VOIDmode)
        {
          value->mode = GET_MODE (x);
          bcopy ((char *) &CONST_DOUBLE_LOW (x),
                 (char *) &value->un.du, sizeof value->un.du);
        }
      else
        {
          value->un.di.low = CONST_DOUBLE_LOW (x);
          value->un.di.high = CONST_DOUBLE_HIGH (x);
        }
      break;

    case CONST_INT:
      value->un.addr.offset = INTVAL (x);
      break;

    case SYMBOL_REF:
    case LABEL_REF:
    case PC:
      value->un.addr.base = x;
      break;

    case CONST:
      x = XEXP (x, 0);
      if (GET_CODE (x) == PLUS)
        {
          value->un.addr.base = XEXP (x, 0);
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            abort ();
          value->un.addr.offset = INTVAL (XEXP (x, 1));
        }
      else if (GET_CODE (x) == MINUS)
        {
          value->un.addr.base = XEXP (x, 0);
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            abort ();
          value->un.addr.offset = - INTVAL (XEXP (x, 1));
        }
      else
        abort ();
      break;

    default:
      abort ();
    }

  if (value->kind == RTX_INT && value->un.addr.base != 0)
    switch (GET_CODE (value->un.addr.base))
      {
      case SYMBOL_REF:
      case LABEL_REF:
        /* Use the string's address, not the SYMBOL_REF's address,
           for the sake of addresses of library routines.
           For a LABEL_REF, compare labels.  */
        value->un.addr.base = XEXP (value->un.addr.base, 0);
        
      default:
        break;
      }
}

/* Given a MINUS expression, simplify it if both sides
   include the same symbol.  */

rtx
simplify_subtraction (x)
     rtx x;
{
  struct rtx_const val0, val1;

  decode_rtx_const (GET_MODE (x), XEXP (x, 0), &val0);
  decode_rtx_const (GET_MODE (x), XEXP (x, 1), &val1);

  if (val0.un.addr.base == val1.un.addr.base)
    return GEN_INT (val0.un.addr.offset - val1.un.addr.offset);
  return x;
}

/* Compute a hash code for a constant RTL expression.  */

static int
const_hash_rtx (mode, x)
     enum machine_mode mode;
     rtx x;
{
  register int hi;
  register size_t i;

  struct rtx_const value;
  decode_rtx_const (mode, x, &value);

  /* Compute hashing function */
  hi = 0;
  for (i = 0; i < sizeof value / sizeof (int); i++)
    hi += ((int *) &value)[i];

  hi &= (1 << HASHBITS) - 1;
  hi %= MAX_RTX_HASH_TABLE;
  return hi;
}

/* Compare a constant rtl object X with a constant-descriptor DESC.
   Return 1 if DESC describes a constant with the same value as X.  */

static int
compare_constant_rtx (mode, x, desc)
     enum machine_mode mode;
     rtx x;
     struct constant_descriptor *desc;
{
  register int *p = (int *) desc->contents;
  register int *strp;
  register int len;
  struct rtx_const value;

  decode_rtx_const (mode, x, &value);
  strp = (int *) &value;
  len = sizeof value / sizeof (int);

  /* Compare constant contents.  */
  while (--len >= 0)
    if (*p++ != *strp++)
      return 0;

  return 1;
}

/* Construct a constant descriptor for the rtl-expression X.
   It is up to the caller to enter the descriptor in the hash table.  */

static struct constant_descriptor *
record_constant_rtx (mode, x)
     enum machine_mode mode;
     rtx x;
{
  struct constant_descriptor *ptr;
  char *label;
  struct rtx_const value;

  decode_rtx_const (mode, x, &value);

  /* Put these things in the saveable obstack so we can ensure it won't
     be freed if we are called from combine or some other phase that discards
     memory allocated from function_obstack (current_obstack).  */
  obstack_grow (saveable_obstack, &ptr, sizeof ptr);
  obstack_grow (saveable_obstack, &label, sizeof label);

  /* Record constant contents.  */
  obstack_grow (saveable_obstack, &value, sizeof value);

  return (struct constant_descriptor *) obstack_finish (saveable_obstack);
}
\f
/* Given a constant rtx X, make (or find) a memory constant for its value
   and return a MEM rtx to refer to it in memory.  */

rtx
force_const_mem (mode, x)
     enum machine_mode mode;
     rtx x;
{
  register int hash;
  register struct constant_descriptor *desc;
  char label[256];
  char *found = 0;
  rtx def;

  /* If we want this CONST_DOUBLE in the same mode as it is in memory
     (this will always be true for floating CONST_DOUBLEs that have been
     placed in memory, but not for VOIDmode (integer) CONST_DOUBLEs),
     use the previous copy.  Otherwise, make a new one.  Note that in
     the unlikely event that this same CONST_DOUBLE is used in two different
     modes in an alternating fashion, we will allocate a lot of different
     memory locations, but this should be extremely rare.  */

  /* Don't use CONST_DOUBLE_MEM in a nested function.
     Nested functions have their own constant pools,
     so they can't share the same values in CONST_DOUBLE_MEM
     with the containing function.  */
  if (outer_function_chain == 0)
    if (GET_CODE (x) == CONST_DOUBLE
        && GET_CODE (CONST_DOUBLE_MEM (x)) == MEM
        && GET_MODE (CONST_DOUBLE_MEM (x)) == mode)
      return CONST_DOUBLE_MEM (x);

  /* Compute hash code of X.  Search the descriptors for that hash code
     to see if any of them describes X.  If yes, the descriptor records
     the label number already assigned.  */

  hash = const_hash_rtx (mode, x);

  for (desc = const_rtx_hash_table[hash]; desc; desc = desc->next)
    if (compare_constant_rtx (mode, x, desc))
      {
        found = desc->label;
        break;
      }

  if (found == 0)
    {
      register struct pool_constant *pool;
      register struct pool_sym *sym;
      int align;

      /* No constant equal to X is known to have been output.
         Make a constant descriptor to enter X in the hash table.
         Assign the label number and record it in the descriptor for
         future calls to this function to find.  */

      desc = record_constant_rtx (mode, x);
      desc->next = const_rtx_hash_table[hash];
      const_rtx_hash_table[hash] = desc;

      /* Align the location counter as required by EXP's data type.  */
      align = (mode == VOIDmode) ? UNITS_PER_WORD : GET_MODE_SIZE (mode);
      if (align > BIGGEST_ALIGNMENT / BITS_PER_UNIT)
        align = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
#ifdef CONSTANT_ALIGNMENT
      align = CONSTANT_ALIGNMENT (make_tree (type_for_mode (mode, 0), x),
                                 align * BITS_PER_UNIT) / BITS_PER_UNIT;
#endif

      pool_offset += align - 1;
      pool_offset &= ~ (align - 1);

      /* If RTL is not being placed into the saveable obstack, make a
         copy of X that is in the saveable obstack in case we are
         being called from combine or some other phase that discards
         memory it allocates.  We used to only do this if it is a
         CONST; however, reload can allocate a CONST_INT when
         eliminating registers.  */
      if (rtl_obstack != saveable_obstack
          && (GET_CODE (x) == CONST || GET_CODE (x) == CONST_INT))
        {
          push_obstacks_nochange ();
          rtl_in_saveable_obstack ();

          if (GET_CODE (x) == CONST)
            x = gen_rtx_CONST (GET_MODE (x), 
                               gen_rtx_PLUS (GET_MODE (x), 
                                             XEXP (XEXP (x, 0), 0),
                                             XEXP (XEXP (x, 0), 1)));
          else
            x = GEN_INT (INTVAL (x));

          pop_obstacks ();
        }

      /* Allocate a pool constant descriptor, fill it in, and chain it in.  */

      pool = (struct pool_constant *) savealloc (sizeof (struct pool_constant));
      pool->desc = desc;
      pool->constant = x;
      pool->mode = mode;
      pool->labelno = const_labelno;
      pool->align = align;
      pool->offset = pool_offset;
      pool->mark = 1;
      pool->next = 0;

      if (last_pool == 0)
        first_pool = pool;
      else
        last_pool->next = pool;

      last_pool = pool;
      pool_offset += GET_MODE_SIZE (mode);

      /* Create a string containing the label name, in LABEL.  */
      ASM_GENERATE_INTERNAL_LABEL (label, "LC", const_labelno);

      ++const_labelno;

      desc->label = found
        = (char *) obstack_copy0 (saveable_obstack, label, strlen (label));

      /* Add label to symbol hash table.  */
      hash = SYMHASH (found);
      sym = (struct pool_sym *) savealloc (sizeof (struct pool_sym));
      sym->label = found;
      sym->pool = pool;
      sym->next = const_rtx_sym_hash_table[hash];
      const_rtx_sym_hash_table[hash] = sym;
    }

  /* We have a symbol name; construct the SYMBOL_REF and the MEM.  */

  def = gen_rtx_MEM (mode, gen_rtx_SYMBOL_REF (Pmode, found));

  RTX_UNCHANGING_P (def) = 1;
  /* Mark the symbol_ref as belonging to this constants pool.  */
  CONSTANT_POOL_ADDRESS_P (XEXP (def, 0)) = 1;
  current_function_uses_const_pool = 1;

  if (outer_function_chain == 0)
    if (GET_CODE (x) == CONST_DOUBLE)
      {
        if (CONST_DOUBLE_MEM (x) == cc0_rtx)
          {
            CONST_DOUBLE_CHAIN (x) = const_double_chain;
            const_double_chain = x;
          }
        CONST_DOUBLE_MEM (x) = def;
      }

  return def;
}
\f
/* Given a SYMBOL_REF with CONSTANT_POOL_ADDRESS_P true, return a pointer to
   the corresponding pool_constant structure.  */

static struct pool_constant *
find_pool_constant (addr)
     rtx addr;
{
  struct pool_sym *sym;
  char *label = XSTR (addr, 0);

  for (sym = const_rtx_sym_hash_table[SYMHASH (label)]; sym; sym = sym->next)
    if (sym->label == label)
      return sym->pool;

  abort ();
}

/* Given a constant pool SYMBOL_REF, return the corresponding constant.  */

rtx
get_pool_constant (addr)
     rtx addr;
{
  return (find_pool_constant (addr))->constant;
}

/* Similar, return the mode.  */

enum machine_mode
get_pool_mode (addr)
     rtx addr;
{
  return (find_pool_constant (addr))->mode;
}

/* Similar, return the offset in the constant pool.  */

int
get_pool_offset (addr)
     rtx addr;
{
  return (find_pool_constant (addr))->offset;
}

/* Return the size of the constant pool.  */

int
get_pool_size ()
{
  return pool_offset;
}
\f
/* Write all the constants in the constant pool.  */

void
output_constant_pool (fnname, fndecl)
  char *fnname ATTRIBUTE_UNUSED;
  tree fndecl ATTRIBUTE_UNUSED;
{
  struct pool_constant *pool;
  rtx x;
  union real_extract u;

  /* It is possible for gcc to call force_const_mem and then to later
     discard the instructions which refer to the constant.  In such a
     case we do not need to output the constant.  */
  mark_constant_pool ();

#ifdef ASM_OUTPUT_POOL_PROLOGUE
  ASM_OUTPUT_POOL_PROLOGUE (asm_out_file, fnname, fndecl, pool_offset);
#endif

  for (pool = first_pool; pool; pool = pool->next)
    {
      x = pool->constant;

      if (! pool->mark)
        continue;

      /* See if X is a LABEL_REF (or a CONST referring to a LABEL_REF)
         whose CODE_LABEL has been deleted.  This can occur if a jump table
         is eliminated by optimization.  If so, write a constant of zero
         instead.  Note that this can also happen by turning the
         CODE_LABEL into a NOTE.  */
      if (((GET_CODE (x) == LABEL_REF
            && (INSN_DELETED_P (XEXP (x, 0))
                || GET_CODE (XEXP (x, 0)) == NOTE)))
          || (GET_CODE (x) == CONST && GET_CODE (XEXP (x, 0)) == PLUS
              && GET_CODE (XEXP (XEXP (x, 0), 0)) == LABEL_REF
              && (INSN_DELETED_P (XEXP (XEXP (XEXP (x, 0), 0), 0))
                  || GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == NOTE)))
        x = const0_rtx;

      /* First switch to correct section.  */
#ifdef SELECT_RTX_SECTION
      SELECT_RTX_SECTION (pool->mode, x);
#else
      readonly_data_section ();
#endif

#ifdef ASM_OUTPUT_SPECIAL_POOL_ENTRY
      ASM_OUTPUT_SPECIAL_POOL_ENTRY (asm_out_file, x, pool->mode,
                                     pool->align, pool->labelno, done);
#endif

      if (pool->align > 1)
        ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (pool->align));

      /* Output the label.  */
      ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LC", pool->labelno);

      /* Output the value of the constant itself.  */
      switch (GET_MODE_CLASS (pool->mode))
        {
        case MODE_FLOAT:
          if (GET_CODE (x) != CONST_DOUBLE)
            abort ();

          bcopy ((char *) &CONST_DOUBLE_LOW (x), (char *) &u, sizeof u);
          assemble_real (u.d, pool->mode);
          break;

        case MODE_INT:
        case MODE_PARTIAL_INT:
          assemble_integer (x, GET_MODE_SIZE (pool->mode), 1);
          break;

        default:
          abort ();
        }

#ifdef ASM_OUTPUT_SPECIAL_POOL_ENTRY
    done: ;
#endif

    }

#ifdef ASM_OUTPUT_POOL_EPILOGUE
  ASM_OUTPUT_POOL_EPILOGUE (asm_out_file, fnname, fndecl, pool_offset);
#endif

  /* Done with this pool.  */
  first_pool = last_pool = 0;
}

/* Look through the instructions for this function, and mark all the
   entries in the constant pool which are actually being used.  */

static void
mark_constant_pool ()
{
  register rtx insn;
  struct pool_constant *pool;

  if (first_pool == 0)
    return;

  for (pool = first_pool; pool; pool = pool->next)
    pool->mark = 0;

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
      mark_constants (PATTERN (insn));

  for (insn = current_function_epilogue_delay_list;
       insn;
       insn = XEXP (insn, 1))
    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
      mark_constants (PATTERN (insn));

  /* It's possible that the only reference to a symbol is in a symbol
     that's in the constant pool.  This happens in Fortran under some
     situations.  (When the constant contains the address of another
     constant, and only the first is used directly in an insn.) 
     This is potentially suboptimal if there's ever a possibility of
     backwards (in pool order) 2'd level references.  However, it's
     not clear that 2'd level references can happen. */
  for (pool = first_pool; pool; pool = pool->next)
    {
      struct pool_sym *sym;
      char *label;

      /* skip unmarked entries; no insn refers to them. */
      if (!pool->mark)
          continue;

      /* skip CONST_DOUBLEs too - correct?  */
      if (GET_CODE (pool->constant) == CONST_DOUBLE)
        continue;
      label = XSTR (pool->constant, 0);

      /* Be sure the symbol's value is marked. */
      for (sym = const_rtx_sym_hash_table[SYMHASH (label)]; sym; 
           sym = sym->next)
          if (sym->label == label)
            sym->pool->mark = 1;
      /* If we didn't find it, there's something truly wrong here, but it
         will be announced by the assembler. */
    }
}

static void
mark_constants (x)
     register rtx x;
{
  register int i;
  register const char *format_ptr;

  if (x == 0)
    return;

  if (GET_CODE (x) == SYMBOL_REF)
    {
      if (CONSTANT_POOL_ADDRESS_P (x))
        find_pool_constant (x)->mark = 1;
      return;
    }
  /* Never search inside a CONST_DOUBLE, because CONST_DOUBLE_MEM may be
     a MEM, but does not constitute a use of that MEM.  This is particularly
     important inside a nested function, because CONST_DOUBLE_MEM may be
     a reference to a MEM in the parent's constant pool.  See the comment
     in force_const_mem.  */
  else if (GET_CODE (x) == CONST_DOUBLE)
    return;

  /* Insns may appear inside a SEQUENCE.  Only check the patterns of
     insns, not any notes that may be attached.  We don't want to mark
     a constant just because it happens to appear in a REG_EQUIV note.  */
  if (GET_RTX_CLASS (GET_CODE (x)) == 'i')
    {
      mark_constants (PATTERN (x));
      return;
    }

  format_ptr = GET_RTX_FORMAT (GET_CODE (x));

  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (x)); i++)
    {
      switch (*format_ptr++)
        {
        case 'e':
          mark_constants (XEXP (x, i));
          break;

        case 'E':
          if (XVEC (x, i) != 0)
            {
              register int j;

              for (j = 0; j < XVECLEN (x, i); j++)
                mark_constants (XVECEXP (x, i, j));
            }
          break;

        case 'S':
        case 's':
        case '0':
        case 'i':
        case 'w':
        case 'n':
        case 'u':
          break;

        default:
          abort ();
        }
    }
}
\f
/* Find all the constants whose addresses are referenced inside of EXP,
   and make sure assembler code with a label has been output for each one.
   Indicate whether an ADDR_EXPR has been encountered.  */

static int
output_addressed_constants (exp)
     tree exp;
{
  int reloc = 0;

  switch (TREE_CODE (exp))
    {
    case ADDR_EXPR:
      {
        register tree constant = TREE_OPERAND (exp, 0);

        while (TREE_CODE (constant) == COMPONENT_REF)
          {
            constant = TREE_OPERAND (constant, 0);
          }

        if (TREE_CODE_CLASS (TREE_CODE (constant)) == 'c'
            || TREE_CODE (constant) == CONSTRUCTOR)
          /* No need to do anything here
             for addresses of variables or functions.  */
          output_constant_def (constant);
      }
      reloc = 1;
      break;

    case PLUS_EXPR:
    case MINUS_EXPR:
      reloc = output_addressed_constants (TREE_OPERAND (exp, 0));
      reloc |= output_addressed_constants (TREE_OPERAND (exp, 1));
      break;

    case NOP_EXPR:
    case CONVERT_EXPR:
    case NON_LVALUE_EXPR:
      reloc = output_addressed_constants (TREE_OPERAND (exp, 0));
      break;

    case CONSTRUCTOR:
      {
        register tree link;
        for (link = CONSTRUCTOR_ELTS (exp); link; link = TREE_CHAIN (link))
          if (TREE_VALUE (link) != 0)
            reloc |= output_addressed_constants (TREE_VALUE (link));
      }
      break;

    default:
      break;
    }
  return reloc;
}
\f
/* Output assembler code for constant EXP to FILE, with no label.
   This includes the pseudo-op such as ".int" or ".byte", and a newline.
   Assumes output_addressed_constants has been done on EXP already.

   Generate exactly SIZE bytes of assembler data, padding at the end
   with zeros if necessary.  SIZE must always be specified.

   SIZE is important for structure constructors,
   since trailing members may have been omitted from the constructor.
   It is also important for initialization of arrays from string constants
   since the full length of the string constant might not be wanted.
   It is also needed for initialization of unions, where the initializer's
   type is just one member, and that may not be as long as the union.

   There a case in which we would fail to output exactly SIZE bytes:
   for a structure constructor that wants to produce more than SIZE bytes.
   But such constructors will never be generated for any possible input.  */

void
output_constant (exp, size)
     register tree exp;
     register int size;
{
  register enum tree_code code = TREE_CODE (TREE_TYPE (exp));

  /* Some front-ends use constants other than the standard
     language-indepdent varieties, but which may still be output
     directly.  Give the front-end a chance to convert EXP to a
     language-independent representation.  */
  if (lang_expand_constant)
    exp = (*lang_expand_constant) (exp);

  if (size == 0 || flag_syntax_only)
    return;

  /* Eliminate the NON_LVALUE_EXPR_EXPR that makes a cast not be an lvalue.
     That way we get the constant (we hope) inside it.  Also, strip off any
     NOP_EXPR that converts between two record, union, array, or set types.  */
  while ((TREE_CODE (exp) == NOP_EXPR 
          && (TREE_TYPE (exp) == TREE_TYPE (TREE_OPERAND (exp, 0))
              || AGGREGATE_TYPE_P (TREE_TYPE (exp))))
         || TREE_CODE (exp) == NON_LVALUE_EXPR)
    exp = TREE_OPERAND (exp, 0);

  /* Allow a constructor with no elements for any data type.
     This means to fill the space with zeros.  */
  if (TREE_CODE (exp) == CONSTRUCTOR && CONSTRUCTOR_ELTS (exp) == 0)
    {
      assemble_zeros (size);
      return;
    }

  switch (code)
    {
    case CHAR_TYPE:
    case BOOLEAN_TYPE:
    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case POINTER_TYPE:
    case REFERENCE_TYPE:
      /* ??? What about       (int)((float)(int)&foo + 4)    */
      while (TREE_CODE (exp) == NOP_EXPR || TREE_CODE (exp) == CONVERT_EXPR
             || TREE_CODE (exp) == NON_LVALUE_EXPR)
        exp = TREE_OPERAND (exp, 0);

      if (! assemble_integer (expand_expr (exp, NULL_RTX, VOIDmode,
                                           EXPAND_INITIALIZER),
                              size, 0))
        error ("initializer for integer value is too complicated");
      size = 0;
      break;

    case REAL_TYPE:
      if (TREE_CODE (exp) != REAL_CST)
        error ("initializer for floating value is not a floating constant");

      assemble_real (TREE_REAL_CST (exp),
                     mode_for_size (size * BITS_PER_UNIT, MODE_FLOAT, 0));
      size = 0;
      break;

    case COMPLEX_TYPE:
      output_constant (TREE_REALPART (exp), size / 2);
      output_constant (TREE_IMAGPART (exp), size / 2);
      size -= (size / 2) * 2;
      break;

    case ARRAY_TYPE:
      if (TREE_CODE (exp) == CONSTRUCTOR)
        {
          output_constructor (exp, size);
          return;
        }
      else if (TREE_CODE (exp) == STRING_CST)
        {
          int excess = 0;

          if (size > TREE_STRING_LENGTH (exp))
            {
              excess = size - TREE_STRING_LENGTH (exp);
              size = TREE_STRING_LENGTH (exp);
            }

          assemble_string (TREE_STRING_POINTER (exp), size);
          size = excess;
        }
      else
        abort ();
      break;

    case RECORD_TYPE:
    case UNION_TYPE:
      if (TREE_CODE (exp) == CONSTRUCTOR)
        output_constructor (exp, size);
      else
        abort ();
      return;

    case SET_TYPE:
      if (TREE_CODE (exp) == INTEGER_CST)
        assemble_integer (expand_expr (exp, NULL_RTX,
                                       VOIDmode, EXPAND_INITIALIZER),
                          size, 1);
      else if (TREE_CODE (exp) == CONSTRUCTOR)
        {
          unsigned char *buffer = (unsigned char *) alloca (size);
          if (get_set_constructor_bytes (exp, buffer, size))
            abort ();
          assemble_string ((char *) buffer, size);
        }
      else
        error ("unknown set constructor type");
      return;

    default:
      break; /* ??? */
    }

  if (size > 0)
    assemble_zeros (size);
}

\f
/* Subroutine of output_constant, used for CONSTRUCTORs
   (aggregate constants).
   Generate at least SIZE bytes, padding if necessary.  */

static void
output_constructor (exp, size)
     tree exp;
     int size;
{
  register tree link, field = 0;
  HOST_WIDE_INT min_index = 0;
  /* Number of bytes output or skipped so far.
     In other words, current position within the constructor.  */
  int total_bytes = 0;
  /* Non-zero means BYTE contains part of a byte, to be output.  */
  int byte_buffer_in_use = 0;
  register int byte;

  if (HOST_BITS_PER_WIDE_INT < BITS_PER_UNIT)
    abort ();

  if (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE)
    field = TYPE_FIELDS (TREE_TYPE (exp));

  if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE
      && TYPE_DOMAIN (TREE_TYPE (exp)) != 0)
    min_index
      = TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (exp))));

  /* As LINK goes through the elements of the constant,
     FIELD goes through the structure fields, if the constant is a structure.
     if the constant is a union, then we override this,
     by getting the field from the TREE_LIST element.
     But the constant could also be an array.  Then FIELD is zero.

     There is always a maximum of one element in the chain LINK for unions
     (even if the initializer in a source program incorrectly contains
     more one). */
  for (link = CONSTRUCTOR_ELTS (exp);
       link;
       link = TREE_CHAIN (link),
       field = field ? TREE_CHAIN (field) : 0)
    {
      tree val = TREE_VALUE (link);
      tree index = 0;

      /* the element in a union constructor specifies the proper field.  */

      if (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE
          || TREE_CODE (TREE_TYPE (exp)) == UNION_TYPE)
        {
          /* if available, use the type given by link */
          if (TREE_PURPOSE (link) != 0)
            field = TREE_PURPOSE (link);
        }

      if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE)
        index = TREE_PURPOSE (link);

      /* Eliminate the marker that makes a cast not be an lvalue.  */
      if (val != 0)
        STRIP_NOPS (val);

      if (index && TREE_CODE (index) == RANGE_EXPR)
        {
          register int fieldsize
            = int_size_in_bytes (TREE_TYPE (TREE_TYPE (exp)));
          HOST_WIDE_INT lo_index = TREE_INT_CST_LOW (TREE_OPERAND (index, 0));
          HOST_WIDE_INT hi_index = TREE_INT_CST_LOW (TREE_OPERAND (index, 1));
          HOST_WIDE_INT index;
          for (index = lo_index; index <= hi_index; index++)
            {
              /* Output the element's initial value.  */
              if (val == 0)
                assemble_zeros (fieldsize);
              else
                output_constant (val, fieldsize);

              /* Count its size.  */
              total_bytes += fieldsize;
            }
        }
      else if (field == 0 || !DECL_BIT_FIELD (field))
        {
          /* An element that is not a bit-field.  */

          register int fieldsize;
          /* Since this structure is static,
             we know the positions are constant.  */
          int bitpos = (field ? (TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field))
                                 / BITS_PER_UNIT)
                        : 0);
          if (index != 0)
            bitpos = (TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (val)))
                      / BITS_PER_UNIT
                      * (TREE_INT_CST_LOW (index) - min_index));

          /* Output any buffered-up bit-fields preceding this element.  */
          if (byte_buffer_in_use)
            {
              ASM_OUTPUT_BYTE (asm_out_file, byte);
              total_bytes++;
              byte_buffer_in_use = 0;
            }

          /* Advance to offset of this element.
             Note no alignment needed in an array, since that is guaranteed
             if each element has the proper size.  */
          if ((field != 0 || index != 0) && bitpos != total_bytes)
            {
              assemble_zeros (bitpos - total_bytes);
              total_bytes = bitpos;
            }

          /* Determine size this element should occupy.  */
          if (field)
            {
              if (TREE_CODE (DECL_SIZE (field)) != INTEGER_CST)
                abort ();
              if (TREE_INT_CST_LOW (DECL_SIZE (field)) > 100000)
                {
                  /* This avoids overflow trouble.  */
                  tree size_tree = size_binop (CEIL_DIV_EXPR,
                                               DECL_SIZE (field),
                                               size_int (BITS_PER_UNIT));
                  fieldsize = TREE_INT_CST_LOW (size_tree);
                }
              else
                {
                  fieldsize = TREE_INT_CST_LOW (DECL_SIZE (field));
                  fieldsize = (fieldsize + BITS_PER_UNIT - 1) / BITS_PER_UNIT;
                }
            }
          else
            fieldsize = int_size_in_bytes (TREE_TYPE (TREE_TYPE (exp)));

          /* Output the element's initial value.  */
          if (val == 0)
            assemble_zeros (fieldsize);
          else
            output_constant (val, fieldsize);

          /* Count its size.  */
          total_bytes += fieldsize;
        }
      else if (val != 0 && TREE_CODE (val) != INTEGER_CST)
        error ("invalid initial value for member `%s'",
               IDENTIFIER_POINTER (DECL_NAME (field)));
      else
        {
          /* Element that is a bit-field.  */

          int next_offset = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
          int end_offset
            = (next_offset + TREE_INT_CST_LOW (DECL_SIZE (field)));

          if (val == 0)
            val = integer_zero_node;

          /* If this field does not start in this (or, next) byte,
             skip some bytes.  */
          if (next_offset / BITS_PER_UNIT != total_bytes)
            {
              /* Output remnant of any bit field in previous bytes.  */
              if (byte_buffer_in_use)
                {
                  ASM_OUTPUT_BYTE (asm_out_file, byte);
                  total_bytes++;
                  byte_buffer_in_use = 0;
                }

              /* If still not at proper byte, advance to there.  */
              if (next_offset / BITS_PER_UNIT != total_bytes)
                {
                  assemble_zeros (next_offset / BITS_PER_UNIT - total_bytes);
                  total_bytes = next_offset / BITS_PER_UNIT;
                }
            }

          if (! byte_buffer_in_use)
            byte = 0;

          /* We must split the element into pieces that fall within
             separate bytes, and combine each byte with previous or
             following bit-fields.  */

          /* next_offset is the offset n fbits from the beginning of
             the structure to the next bit of this element to be processed.
             end_offset is the offset of the first bit past the end of
             this element.  */
          while (next_offset < end_offset)
            {
              int this_time;
              int shift;
              HOST_WIDE_INT value;
              int next_byte = next_offset / BITS_PER_UNIT;
              int next_bit = next_offset % BITS_PER_UNIT;

              /* Advance from byte to byte
                 within this element when necessary.  */
              while (next_byte != total_bytes)
                {
                  ASM_OUTPUT_BYTE (asm_out_file, byte);
                  total_bytes++;
                  byte = 0;
                }

              /* Number of bits we can process at once
                 (all part of the same byte).  */
              this_time = MIN (end_offset - next_offset,
                               BITS_PER_UNIT - next_bit);
              if (BYTES_BIG_ENDIAN)
                {
                  /* On big-endian machine, take the most significant bits
                     first (of the bits that are significant)
                     and put them into bytes from the most significant end.  */
                  shift = end_offset - next_offset - this_time;
                  /* Don't try to take a bunch of bits that cross
                     the word boundary in the INTEGER_CST.  */
                  if (shift < HOST_BITS_PER_WIDE_INT
                      && shift + this_time > HOST_BITS_PER_WIDE_INT)
                    {
                      this_time -= (HOST_BITS_PER_WIDE_INT - shift);
                      shift = HOST_BITS_PER_WIDE_INT;
                    }

                  /* Now get the bits from the appropriate constant word.  */
                  if (shift < HOST_BITS_PER_WIDE_INT)
                    {
                      value = TREE_INT_CST_LOW (val);
                    }
                  else if (shift < 2 * HOST_BITS_PER_WIDE_INT)
                    {
                      value = TREE_INT_CST_HIGH (val);
                      shift -= HOST_BITS_PER_WIDE_INT;
                    }
                  else
                    abort ();
                  byte |= (((value >> shift)
                            & (((HOST_WIDE_INT) 1 << this_time) - 1))
                           << (BITS_PER_UNIT - this_time - next_bit));
                }
              else
                {
                  /* On little-endian machines,
                     take first the least significant bits of the value
                     and pack them starting at the least significant
                     bits of the bytes.  */
                  shift = (next_offset
                           - TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field)));
                  /* Don't try to take a bunch of bits that cross
                     the word boundary in the INTEGER_CST.  */
                  if (shift < HOST_BITS_PER_WIDE_INT
                      && shift + this_time > HOST_BITS_PER_WIDE_INT)
                    {
                      this_time -= (HOST_BITS_PER_WIDE_INT - shift);
                      shift = HOST_BITS_PER_WIDE_INT;
                    }

                  /* Now get the bits from the appropriate constant word.  */
                  if (shift < HOST_BITS_PER_WIDE_INT)
                    value = TREE_INT_CST_LOW (val);
                  else if (shift < 2 * HOST_BITS_PER_WIDE_INT)
                    {
                      value = TREE_INT_CST_HIGH (val);
                      shift -= HOST_BITS_PER_WIDE_INT;
                    }
                  else
                    abort ();
                  byte |= (((value >> shift)
                            & (((HOST_WIDE_INT) 1 << this_time) - 1))
                           << next_bit);
                }
              next_offset += this_time;
              byte_buffer_in_use = 1;
            }
        }
    }
  if (byte_buffer_in_use)
    {
      ASM_OUTPUT_BYTE (asm_out_file, byte);
      total_bytes++;
    }
  if (total_bytes < size)
    assemble_zeros (size - total_bytes);
}

#ifdef HANDLE_PRAGMA_WEAK
/* Add function NAME to the weak symbols list.  VALUE is a weak alias
   associatd with NAME.  */
   
int
add_weak (name, value)
     char *name;
     char *value;
{
  struct weak_syms *weak;

  weak = (struct weak_syms *) permalloc (sizeof (struct weak_syms));

  if (weak == NULL)
    return 0;

  weak->next = weak_decls;
  weak->name = name;
  weak->value = value;
  weak_decls = weak;

  return 1;
}
#endif /* HANDLE_PRAGMA_WEAK */

/* Declare DECL to be a weak symbol.  */

void
declare_weak (decl)
     tree decl;
{
  if (! TREE_PUBLIC (decl))
    error_with_decl (decl, "weak declaration of `%s' must be public");
  else if (TREE_ASM_WRITTEN (decl))
    error_with_decl (decl, "weak declaration of `%s' must precede definition");
  else if (SUPPORTS_WEAK)
    DECL_WEAK (decl) = 1;
#ifdef HANDLE_PRAGMA_WEAK
   add_weak (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)), NULL);
#endif
}

/* Emit any pending weak declarations.  */

#ifdef HANDLE_PRAGMA_WEAK
struct weak_syms * weak_decls;
#endif

void
weak_finish ()
{
#ifdef HANDLE_PRAGMA_WEAK
  if (HANDLE_PRAGMA_WEAK)
    {
      struct weak_syms *t;
      for (t = weak_decls; t; t = t->next)
        {
          if (t->name)
            {
              ASM_WEAKEN_LABEL (asm_out_file, t->name);
              if (t->value)
                ASM_OUTPUT_DEF (asm_out_file, t->name, t->value);
            }
        }
    }
#endif
}

/* Remove NAME from the pending list of weak symbols.  This prevents
   the compiler from emitting multiple .weak directives which confuses
   some assemblers.  */
static void
remove_from_pending_weak_list (name)
     char *name ATTRIBUTE_UNUSED;
{
#ifdef HANDLE_PRAGMA_WEAK
  if (HANDLE_PRAGMA_WEAK)
    {
      struct weak_syms *t;
      for (t = weak_decls; t; t = t->next)
        {
          if (t->name && strcmp (name, t->name) == 0)
            t->name = NULL;
        }
    }
#endif
}

void
assemble_alias (decl, target)
     tree decl, target ATTRIBUTE_UNUSED;
{
  char *name;

  make_decl_rtl (decl, (char *) 0, 1);
  name = XSTR (XEXP (DECL_RTL (decl), 0), 0);

#ifdef ASM_OUTPUT_DEF
  /* Make name accessible from other files, if appropriate.  */

  if (TREE_PUBLIC (decl))
    {
#ifdef ASM_WEAKEN_LABEL
      if (DECL_WEAK (decl))
        {
          ASM_WEAKEN_LABEL (asm_out_file, name);
          /* Remove this function from the pending weak list so that
             we do not emit multiple .weak directives for it.  */
          remove_from_pending_weak_list
            (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)));
        }
      else
#endif
        ASM_GLOBALIZE_LABEL (asm_out_file, name);
    }

#ifdef ASM_OUTPUT_DEF_FROM_DECLS
  ASM_OUTPUT_DEF_FROM_DECLS (asm_out_file, decl, target);
#else
  ASM_OUTPUT_DEF (asm_out_file, name, IDENTIFIER_POINTER (target));
#endif
  TREE_ASM_WRITTEN (decl) = 1;
#else
#ifdef ASM_OUTPUT_WEAK_ALIAS
  if (! DECL_WEAK (decl))
    warning ("only weak aliases are supported in this configuration");

  ASM_OUTPUT_WEAK_ALIAS (asm_out_file, name, IDENTIFIER_POINTER (target));
  TREE_ASM_WRITTEN (decl) = 1;
#else
  warning ("alias definitions not supported in this configuration; ignored");
#endif
#endif
}

/* This determines whether or not we support link-once semantics.  */
#ifndef SUPPORTS_ONE_ONLY
#ifdef MAKE_DECL_ONE_ONLY
#define SUPPORTS_ONE_ONLY 1
#else
#define SUPPORTS_ONE_ONLY 0
#endif
#endif

/* Returns 1 if the target configuration supports defining public symbols
   so that one of them will be chosen at link time instead of generating a
   multiply-defined symbol error, whether through the use of weak symbols or
   a target-specific mechanism for having duplicates discarded.  */

int
supports_one_only ()
{
  if (SUPPORTS_ONE_ONLY)
    return 1;
  return SUPPORTS_WEAK;
}

/* Set up DECL as a public symbol that can be defined in multiple
   translation units without generating a linker error.  */

void
make_decl_one_only (decl)
     tree decl;
{
  if (TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FUNCTION_DECL)
    abort ();

  TREE_PUBLIC (decl) = 1;

  if (TREE_CODE (decl) == VAR_DECL
      && (DECL_INITIAL (decl) == 0 || DECL_INITIAL (decl) == error_mark_node))
    DECL_COMMON (decl) = 1;
  else if (SUPPORTS_ONE_ONLY)
    {
#ifdef MAKE_DECL_ONE_ONLY
      MAKE_DECL_ONE_ONLY (decl);
#endif
      DECL_ONE_ONLY (decl) = 1;
    }
  else if (SUPPORTS_WEAK)
    DECL_WEAK (decl) = 1;
  else
    abort ();
}