* tm.texi: Fix markup.

[official-gcc.git] / gcc / config / darwin.c

/* Functions for generic Darwin as target machine for GNU C compiler.
   Copyright (C) 1989, 1990, 1991, 1992, 1993, 2000, 2001
   Free Software Foundation, Inc.
   Contributed by Apple Computer 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.  */

#include "config.h"
#include "system.h"
#include "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "real.h"
#include "insn-config.h"
#include "conditions.h"
#include "insn-flags.h"
#include "output.h"
#include "insn-attr.h"
#include "flags.h"
#include "tree.h"
#include "expr.h"
#include "reload.h"
#include "function.h"
#include "ggc.h"

#include "darwin-protos.h"

extern void machopic_output_stub PARAMS ((FILE *, const char *, const char *));

static int machopic_data_defined_p PARAMS ((const char *));
static int func_name_maybe_scoped PARAMS ((const char *));
static void update_non_lazy_ptrs PARAMS ((const char *));

int
name_needs_quotes (name)
     const char *name;
{
  int c;
  while ((c = *name++) != '\0')
    if (!isalnum (c) && c != '_')
      return 1;
  return 0;
}

/* 
 * flag_pic = 1 ... generate only indirections
 * flag_pic = 2 ... generate indirections and pure code
 */

/* This module assumes that (const (symbol_ref "foo")) is a legal pic
   reference, which will not be changed.  */

static tree machopic_defined_list;

enum machopic_addr_class
machopic_classify_ident (ident)
     tree ident;
{
  const char *name = IDENTIFIER_POINTER (ident);
  int lprefix = (((name[0] == '*' || name[0] == '&')
                  && (name[1] == 'L' || (name[1] == '"' && name[2] == 'L')))
                 || (   name[0] == '_' 
                     && name[1] == 'O' 
                     && name[2] == 'B' 
                     && name[3] == 'J'
                     && name[4] == 'C'
                     && name[5] == '_'));
  tree temp;

  if (name[0] != '!')
    {
      /* Here if no special encoding to be found.  */
      if (lprefix)
        {
          const char *name = IDENTIFIER_POINTER (ident);
          int len = strlen (name);

          if ((len > 5 && !strcmp (name + len - 5, "$stub"))
              || (len > 6 && !strcmp (name + len - 6, "$stub\"")))
            return MACHOPIC_DEFINED_FUNCTION;
          return MACHOPIC_DEFINED_DATA;
        }

      for (temp = machopic_defined_list;
           temp != NULL_TREE;
           temp = TREE_CHAIN (temp))
        {
          if (ident == TREE_VALUE (temp))
            return MACHOPIC_DEFINED_DATA;
        }

      if (TREE_ASM_WRITTEN (ident))
        return MACHOPIC_DEFINED_DATA;

      return MACHOPIC_UNDEFINED;
    }

  else if (name[1] == 'D')
    return MACHOPIC_DEFINED_DATA;

  else if (name[1] == 'T')
    return MACHOPIC_DEFINED_FUNCTION;

  for (temp = machopic_defined_list; temp != NULL_TREE; temp = TREE_CHAIN (temp))
    {
      if (ident == TREE_VALUE (temp))
        {
          if (name[1] == 'T')
            return MACHOPIC_DEFINED_FUNCTION;
          else
            return MACHOPIC_DEFINED_DATA;
        }
    }
  
  if (name[1] == 't' || name[1] == 'T')
    {
      if (lprefix)
        return MACHOPIC_DEFINED_FUNCTION;
      else
        return MACHOPIC_UNDEFINED_FUNCTION;
    }
  else
    {
      if (lprefix)
        return MACHOPIC_DEFINED_DATA;
      else
        return MACHOPIC_UNDEFINED_DATA;
    }
}

     
enum machopic_addr_class
machopic_classify_name (name)
     const char *name;
{
  return machopic_classify_ident (get_identifier (name));
}

int
machopic_ident_defined_p (ident)
     tree ident;
{
  switch (machopic_classify_ident (ident))
    {
    case MACHOPIC_UNDEFINED:
    case MACHOPIC_UNDEFINED_DATA:
    case MACHOPIC_UNDEFINED_FUNCTION:
      return 0;
    default:
      return 1;
    }
}

static int
machopic_data_defined_p (name)
     const char *name;
{
  switch (machopic_classify_ident (get_identifier (name)))
    {
    case MACHOPIC_DEFINED_DATA:
      return 1;
    default:
      return 0;
    }
}

int
machopic_name_defined_p (name)
     const char *name;
{
  return machopic_ident_defined_p (get_identifier (name));
}

void
machopic_define_ident (ident)
     tree ident;
{
  if (!machopic_ident_defined_p (ident))
    machopic_defined_list = 
      tree_cons (NULL_TREE, ident, machopic_defined_list);
}

void
machopic_define_name (name)
     const char *name;
{
  machopic_define_ident (get_identifier (name));
}

/* This is a static to make inline functions work.  The rtx
   representing the PIC base symbol always points to here. */

static char function_base[32];

static int current_pic_label_num;

char *
machopic_function_base_name ()
{
  static char *name = NULL;
  static const char *current_name;

  current_name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (current_function_decl));

  if (name != current_name)
    {
      current_function_uses_pic_offset_table = 1;

      /* Save mucho space and time.  Some of the C++ mangled names are over
         700 characters long!  Note that we produce a label containing a '-'
         if the function we're compiling is an Objective-C method, as evinced
         by the incredibly scientific test below.  This is because code in
         rs6000.c makes the same ugly test when loading the PIC reg.  */
 
      ++current_pic_label_num;
      if (*current_name == '+' || *current_name == '-')
        sprintf (function_base, "*\"L-%d$pb\"", current_pic_label_num);
      else
        sprintf (function_base, "*L%d$pb", current_pic_label_num);

      name = current_name;
    }

  return function_base;
}

static tree machopic_non_lazy_pointers = NULL;

/* Return a non-lazy pointer name corresponding to the given name,
   either by finding it in our list of pointer names, or by generating
   a new one.  */

char * 
machopic_non_lazy_ptr_name (name)
     const char *name;
{
  char *temp_name;
  tree temp, ident = get_identifier (name);
  
  for (temp = machopic_non_lazy_pointers;
       temp != NULL_TREE; 
       temp = TREE_CHAIN (temp))
    {
      if (ident == TREE_VALUE (temp))
        return IDENTIFIER_POINTER (TREE_PURPOSE (temp));
    }

  STRIP_NAME_ENCODING (name, name);

  /* Try again, but comparing names this time.  */
  for (temp = machopic_non_lazy_pointers;
       temp != NULL_TREE; 
       temp = TREE_CHAIN (temp))
    {
      if (TREE_VALUE (temp))
        {
          temp_name = IDENTIFIER_POINTER (TREE_VALUE (temp));
          STRIP_NAME_ENCODING (temp_name, temp_name);
          if (strcmp (name, temp_name) == 0)
            return IDENTIFIER_POINTER (TREE_PURPOSE (temp));
        }
    }

  {
    char *buffer;
    tree ptr_name;

    buffer = alloca (strlen (name) + 20);

    strcpy (buffer, "&L");
    if (name[0] == '*')
      strcat (buffer, name+1);
    else
      {
        strcat (buffer, "_");
        strcat (buffer, name);
      }
      
    strcat (buffer, "$non_lazy_ptr");
    ptr_name = get_identifier (buffer);

    machopic_non_lazy_pointers 
      = tree_cons (ptr_name, ident, machopic_non_lazy_pointers);

    TREE_USED (machopic_non_lazy_pointers) = 0;

    return IDENTIFIER_POINTER (ptr_name);
  }
}

static tree machopic_stubs = 0;

/* Make sure the GC knows about our homemade lists.  */

void
machopic_add_gc_roots ()
{
  ggc_add_tree_root (&machopic_defined_list, 1);
  ggc_add_tree_root (&machopic_non_lazy_pointers, 1);
  ggc_add_tree_root (&machopic_stubs, 1);
}

/* Return the name of the stub corresponding to the given name,
   generating a new stub name if necessary.  */

char * 
machopic_stub_name (name)
     const char *name;
{
  tree temp, ident = get_identifier (name);
  
  for (temp = machopic_stubs;
       temp != NULL_TREE; 
       temp = TREE_CHAIN (temp))
    {
      if (ident == TREE_VALUE (temp))
        return IDENTIFIER_POINTER (TREE_PURPOSE (temp));
    }

  STRIP_NAME_ENCODING (name, name);

  {
    char *buffer;
    tree ptr_name;
    int needs_quotes = name_needs_quotes (name);

    buffer = alloca (strlen (name) + 20);

    if (needs_quotes)
      strcpy (buffer, "&\"L");
    else
      strcpy (buffer, "&L");
    if (name[0] == '*')
      {
        strcat (buffer, name+1);
      }
    else
      {
        strcat (buffer, "_");
        strcat (buffer, name);
      }

    if (needs_quotes)
      strcat (buffer, "$stub\"");
    else
      strcat (buffer, "$stub");
    ptr_name = get_identifier (buffer);

    machopic_stubs = tree_cons (ptr_name, ident, machopic_stubs);
    TREE_USED (machopic_stubs) = 0;

    return IDENTIFIER_POINTER (ptr_name);
  }
}

void
machopic_validate_stub_or_non_lazy_ptr (name, validate_stub)
     const char *name;
     int validate_stub;
{
  char *real_name;
  tree temp, ident = get_identifier (name), id2;

    for (temp = (validate_stub ? machopic_stubs : machopic_non_lazy_pointers);
         temp != NULL_TREE;
         temp = TREE_CHAIN (temp))
      if (ident == TREE_PURPOSE (temp))
        {
          /* Mark both the stub or non-lazy pointer as well as the
             original symbol as being referenced.  */
          TREE_USED (temp) = 1;
          if (TREE_CODE (TREE_VALUE (temp)) == IDENTIFIER_NODE)
            TREE_SYMBOL_REFERENCED (TREE_VALUE (temp)) = 1;
          STRIP_NAME_ENCODING (real_name, IDENTIFIER_POINTER (TREE_VALUE (temp)));
          id2 = maybe_get_identifier (real_name);
          if (id2)
            TREE_SYMBOL_REFERENCED (id2) = 1;
        }
}

/* Transform ORIG, which may be any data source, to the corresponding
   source using indirections.  */

rtx
machopic_indirect_data_reference (orig, reg)
     rtx orig, reg;
{
  rtx ptr_ref = orig;
  
  if (! MACHOPIC_INDIRECT)
    return orig;

  if (GET_CODE (orig) == SYMBOL_REF)
    {
      const char *name = XSTR (orig, 0);

      if (machopic_data_defined_p (name))
        {
          rtx pic_base = gen_rtx (SYMBOL_REF, Pmode, 
                                  machopic_function_base_name ());
          rtx offset = gen_rtx (CONST, Pmode,
                                gen_rtx (MINUS, Pmode, orig, pic_base));

#if defined (TARGET_TOC) /* i.e., PowerPC */
          rtx hi_sum_reg = reg;

          if (reg == NULL)
            abort ();

          emit_insn (gen_rtx (SET, Pmode, hi_sum_reg,
                              gen_rtx (PLUS, Pmode, pic_offset_table_rtx,
                                       gen_rtx (HIGH, Pmode, offset))));
          emit_insn (gen_rtx (SET, Pmode, reg,
                              gen_rtx (LO_SUM, Pmode, hi_sum_reg, offset)));

          orig = reg;
#else
#if defined (HAVE_lo_sum)
          if (reg == 0) abort ();

          emit_insn (gen_rtx (SET, VOIDmode, reg,
                              gen_rtx (HIGH, Pmode, offset)));
          emit_insn (gen_rtx (SET, VOIDmode, reg,
                              gen_rtx (LO_SUM, Pmode, reg, offset)));
          emit_insn (gen_rtx (USE, VOIDmode,
                              gen_rtx_REG (Pmode, PIC_OFFSET_TABLE_REGNUM)));

          orig = gen_rtx (PLUS, Pmode, pic_offset_table_rtx, reg);
#endif
#endif
          return orig;
        }

      ptr_ref = gen_rtx (SYMBOL_REF, Pmode,
                         machopic_non_lazy_ptr_name (name));

      ptr_ref = gen_rtx_MEM (Pmode, ptr_ref);
      RTX_UNCHANGING_P (ptr_ref) = 1;

      return ptr_ref;
    }
  else if (GET_CODE (orig) == CONST)
    {
      rtx base, result;

      /* legitimize both operands of the PLUS */
      if (GET_CODE (XEXP (orig, 0)) == PLUS)
        {
          base = machopic_indirect_data_reference (XEXP (XEXP (orig, 0), 0),
                                                   reg);
          orig = machopic_indirect_data_reference (XEXP (XEXP (orig, 0), 1),
                                                   (base == reg ? 0 : reg));
        }
      else 
        return orig;

      if (MACHOPIC_PURE && GET_CODE (orig) == CONST_INT)
        result = plus_constant (base, INTVAL (orig));
      else
        result = gen_rtx (PLUS, Pmode, base, orig);

      if (RTX_UNCHANGING_P (base) && RTX_UNCHANGING_P (orig))
        RTX_UNCHANGING_P (result) = 1;

      if (MACHOPIC_JUST_INDIRECT && GET_CODE (base) == MEM)
        {
          if (reg)
            {
              emit_move_insn (reg, result);
              result = reg;
            }
          else
            {
              result = force_reg (GET_MODE (result), result);
            }
        }

      return result;

    }
  else if (GET_CODE (orig) == MEM)
    XEXP (ptr_ref, 0) = machopic_indirect_data_reference (XEXP (orig, 0), reg);
  /* When the target is i386, this code prevents crashes due to the
     compiler's ignorance on how to move the PIC base register to
     other registers.  (The reload phase sometimes introduces such
     insns.)  */
  else if (GET_CODE (orig) == PLUS
           && GET_CODE (XEXP (orig, 0)) == REG
           && REGNO (XEXP (orig, 0)) == PIC_OFFSET_TABLE_REGNUM
#ifdef I386
           /* Prevent the same register from being erroneously used
              as both the base and index registers.  */
           && GET_CODE (XEXP (orig, 1)) == CONST
#endif
           && reg)
    {
      emit_move_insn (reg, XEXP (orig, 0));
      XEXP (ptr_ref, 0) = reg;
    }
  return ptr_ref;
}

/* For MACHOPIC_INDIRECT_CALL_TARGET below, we need to beware of:

        extern "C" { int f(); }
        struct X { int f(); int g(); };
        int X::f() { ::f(); }
        int X::g() { ::f(); f();}

  This is hairy.  Both calls to "::f()" need to be indirect (i.e., to
  appropriate symbol stubs), but since MACHOPIC_NAME_DEFINED_P calls
  GET_IDENTIFIER which treats "f" as "X::f", and "X::f" is indeed (being)
  defined somewhere in "X"'s inheritance hierarchy, MACHOPIC_NAME_DEFINED_P
  returns TRUE when called with "f", which means that
  MACHOPIC_INDIRECT_CALL_TARGET uses an "internal" call instead of an
  indirect one as it should.

  Our quick-n-dirty solution to this is to call the following
  FUNC_NAME_MAYBE_SCOPED routine which (only for C++) checks whether
  FNAME -- the name of the function which we're calling -- is NOT a
  mangled C++ name, AND if the current function being compiled is a
  method, and if so, use an "external" or "indirect" call. 

  Note that this function will be called ONLY when MACHOPIC_INDIRECT_TARGET_P
  has already indicated that the target is NOT indirect.

  This conservative solution will sometimes make indirect calls where
  it might have been possible to make direct ones.

  FUNC_NAME_MAYBE_SCOPED returns 1 to indicate a "C" name (not scoped),
  which in turns means we should create a stub for an indirect call.
  */

static int is_cplusplus = -1;

static int
func_name_maybe_scoped (fname)
     const char *fname;
{

  if (is_cplusplus < 0)
    is_cplusplus = (strcmp (lang_identify (), "cplusplus") == 0);

  if (is_cplusplus)
    {
      /* If we have a method, then check whether the function we're trying to
         call is a "C" function.  If so, we should use an indirect call.

         It turns out to be hard to tell whether "we have a method", since
         static member functions have a TREE_CODE of FUNCTION_TYPE, as do
         namespace-level non-member functions.  So here, we always look for
         an extern-"C"-like name, and make stubs for them no matter the
         calling context.  This is temporary, and leaves nagging suspicion
         that improvements should be possible here.  (I.e., I suspect that
         it can still sometimes make stubs where it needn't.)  */

      /* if (1 || TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE) */
        {
          /* If fname is of the form "f__1X" or "f__Fv", it's C++.  */
          while (*fname == '_') ++fname;        /* skip leading underscores  */
          while (*fname != 0)
            {
              if (fname[0] == '_' && fname[1] == '_'
                  && (fname[2] == 'F' || (fname[2] >= '0' && fname[2] <= '9')))
                return 0;
              ++fname;
            }
          /* Not a C++ mangled name: must be "C", in which case play safe.  */
          return 1;
        }
    }
  return 0;
}

/* Transform TARGET (a MEM), which is a function call target, to the
   corresponding symbol_stub if necessary.  Return a new MEM.  */

rtx
machopic_indirect_call_target (target)
     rtx target;
{
  if (GET_CODE (target) != MEM)
    return target;

  if (MACHOPIC_INDIRECT && GET_CODE (XEXP (target, 0)) == SYMBOL_REF)
    { 
      enum machine_mode mode = GET_MODE (XEXP (target, 0));
      const char *name = XSTR (XEXP (target, 0), 0);

      if (!machopic_name_defined_p (name) || func_name_maybe_scoped (name)) 
        {
          const char *stub_name = machopic_stub_name (name);

          XEXP (target, 0) = gen_rtx (SYMBOL_REF, mode, stub_name);
          RTX_UNCHANGING_P (target) = 1;
        } 
    }

  return target;
}

rtx
machopic_legitimize_pic_address (orig, mode, reg)
     rtx orig, reg;
     enum machine_mode mode;
{
  rtx pic_ref = orig;

  if (! MACHOPIC_PURE)
    return orig;

  /* First handle a simple SYMBOL_REF or LABEL_REF */
  if (GET_CODE (orig) == LABEL_REF
      || (GET_CODE (orig) == SYMBOL_REF
          ))
    {
      /* addr(foo) = &func+(foo-func) */
      rtx pic_base;

      orig = machopic_indirect_data_reference (orig, reg);

      if (GET_CODE (orig) == PLUS 
          && GET_CODE (XEXP (orig, 0)) == REG)
        {
          if (reg == 0)
            return force_reg (mode, orig);

          emit_move_insn (reg, orig);
          return reg;
        }  

      pic_base = gen_rtx (SYMBOL_REF, Pmode, machopic_function_base_name ());

      if (GET_CODE (orig) == MEM)
        {
          if (reg == 0)
            {
              if (reload_in_progress)
                abort ();
              else
                reg = gen_reg_rtx (Pmode);
            }
        
#ifdef HAVE_lo_sum
          if (GET_CODE (XEXP (orig, 0)) == SYMBOL_REF 
              || GET_CODE (XEXP (orig, 0)) == LABEL_REF)
            {
              rtx offset = gen_rtx (CONST, Pmode,
                                    gen_rtx (MINUS, Pmode,
                                             XEXP (orig, 0), pic_base));
#if defined (TARGET_TOC) /* i.e., PowerPC */
              /* Generating a new reg may expose opportunities for
                 common subexpression elimination.  */
              rtx hi_sum_reg =
                (reload_in_progress ? reg : gen_reg_rtx (SImode));

              emit_insn (gen_rtx (SET, Pmode, hi_sum_reg,
                                  gen_rtx (PLUS, Pmode,
                                           pic_offset_table_rtx,
                                           gen_rtx (HIGH, Pmode, offset))));
              emit_insn (gen_rtx (SET, VOIDmode, reg,
                                  gen_rtx (MEM, GET_MODE (orig),
                                           gen_rtx (LO_SUM, Pmode, 
                                                    hi_sum_reg, offset))));
              pic_ref = reg;

#else
              emit_insn (gen_rtx (USE, VOIDmode,
                              gen_rtx_REG (Pmode, PIC_OFFSET_TABLE_REGNUM)));

              emit_insn (gen_rtx (SET, VOIDmode, reg,
                                  gen_rtx (HIGH, Pmode, 
                                           gen_rtx (CONST, Pmode, offset))));
              emit_insn (gen_rtx (SET, VOIDmode, reg,
                                  gen_rtx (LO_SUM, Pmode, reg, 
                                           gen_rtx (CONST, Pmode, offset))));
              pic_ref = gen_rtx (PLUS, Pmode,
                                 pic_offset_table_rtx, reg);
#endif
            }
          else
#endif  /* HAVE_lo_sum */
            {
              rtx pic = pic_offset_table_rtx;
              if (GET_CODE (pic) != REG)
                {
                  emit_move_insn (reg, pic);
                  pic = reg;
                }
#if 0
              emit_insn (gen_rtx (USE, VOIDmode,
                                  gen_rtx (REG, Pmode, PIC_OFFSET_TABLE_REGNUM)));
#endif

              pic_ref = gen_rtx (PLUS, Pmode,
                                 pic, 
                                 gen_rtx (CONST, Pmode, 
                                          gen_rtx (MINUS, Pmode,
                                                   XEXP (orig, 0), 
                                                   pic_base)));
            }
          
#if !defined (TARGET_TOC)
          RTX_UNCHANGING_P (pic_ref) = 1;
          emit_move_insn (reg, pic_ref);
          pic_ref = gen_rtx (MEM, GET_MODE (orig), reg);
#endif
        }
      else
        {

#ifdef HAVE_lo_sum
          if (GET_CODE (orig) == SYMBOL_REF 
              || GET_CODE (orig) == LABEL_REF)
            {
              rtx offset = gen_rtx (CONST, Pmode,
                                    gen_rtx (MINUS, Pmode, orig, pic_base));
#if defined (TARGET_TOC) /* i.e., PowerPC */
              rtx hi_sum_reg;

              if (reg == 0)
                {
                  if (reload_in_progress)
                    abort ();
                  else
                    reg = gen_reg_rtx (SImode);
                }
        
              hi_sum_reg = reg;

              emit_insn (gen_rtx (SET, Pmode, hi_sum_reg,
                                  gen_rtx (PLUS, Pmode,
                                           pic_offset_table_rtx,
                                           gen_rtx (HIGH, Pmode, offset))));
              emit_insn (gen_rtx (SET, VOIDmode, reg,
                                  gen_rtx (LO_SUM, Pmode,
                                           hi_sum_reg, offset)));
              pic_ref = reg;
#else
              emit_insn (gen_rtx (SET, VOIDmode, reg,
                                  gen_rtx (HIGH, Pmode, offset)));
              emit_insn (gen_rtx (SET, VOIDmode, reg,
                                  gen_rtx (LO_SUM, Pmode, reg, offset)));
              pic_ref = gen_rtx (PLUS, Pmode,
                                 pic_offset_table_rtx, reg);
#endif
            }
          else
#endif  /*  HAVE_lo_sum  */
            {
              if (GET_CODE (orig) == REG)
                {
                  return orig;
                }
              else
                {
                  rtx pic = pic_offset_table_rtx;
                  if (GET_CODE (pic) != REG)
                    {
                      emit_move_insn (reg, pic);
                      pic = reg;
                    }
#if 0
                  emit_insn (gen_rtx (USE, VOIDmode,
                                      pic_offset_table_rtx));
#endif
                  pic_ref = gen_rtx (PLUS, Pmode,
                                     pic,
                                     gen_rtx (CONST, Pmode, 
                                              gen_rtx (MINUS, Pmode,
                                                       orig, pic_base)));
                }
            }
        }

      RTX_UNCHANGING_P (pic_ref) = 1;

      if (GET_CODE (pic_ref) != REG)
        {
          if (reg != 0)
            {
              emit_move_insn (reg, pic_ref);
              return reg;
            }
          else
            {
              return force_reg (mode, pic_ref);
            }
        }
      else
        {
          return pic_ref;
        }
    }

  else if (GET_CODE (orig) == SYMBOL_REF)
    return orig;

  else if (GET_CODE (orig) == PLUS
           && (GET_CODE (XEXP (orig, 0)) == MEM
               || GET_CODE (XEXP (orig, 0)) == SYMBOL_REF
               || GET_CODE (XEXP (orig, 0)) == LABEL_REF)
           && XEXP (orig, 0) != pic_offset_table_rtx
           && GET_CODE (XEXP (orig, 1)) != REG)
    
    {
      rtx base;
      int is_complex = (GET_CODE (XEXP (orig, 0)) == MEM);

      base = machopic_legitimize_pic_address (XEXP (orig, 0), Pmode, reg);
      orig = machopic_legitimize_pic_address (XEXP (orig, 1),
                                              Pmode, (base == reg ? 0 : reg));
      if (GET_CODE (orig) == CONST_INT)
        {
          pic_ref = plus_constant (base, INTVAL (orig));
          is_complex = 1;
        }
      else
        pic_ref = gen_rtx (PLUS, Pmode, base, orig);

      if (RTX_UNCHANGING_P (base) && RTX_UNCHANGING_P (orig))
        RTX_UNCHANGING_P (pic_ref) = 1;

      if (reg && is_complex)
        {
          emit_move_insn (reg, pic_ref);
          pic_ref = reg;
        }
      /* Likewise, should we set special REG_NOTEs here?  */
    }

  else if (GET_CODE (orig) == CONST)
    {
      return machopic_legitimize_pic_address (XEXP (orig, 0), Pmode, reg);
    }

  else if (GET_CODE (orig) == MEM
           && GET_CODE (XEXP (orig, 0)) == SYMBOL_REF)
    {
      rtx addr = machopic_legitimize_pic_address (XEXP (orig, 0), Pmode, reg);

      addr = gen_rtx (MEM, GET_MODE (orig), addr);
      RTX_UNCHANGING_P (addr) = RTX_UNCHANGING_P (orig);
      emit_move_insn (reg, addr);
      pic_ref = reg;
    }

  return pic_ref;
}


void
machopic_finish (asm_out_file)
     FILE *asm_out_file;
{
  tree temp;

  for (temp = machopic_stubs;
       temp != NULL_TREE;
       temp = TREE_CHAIN (temp))
    {
      char *sym_name = IDENTIFIER_POINTER (TREE_VALUE (temp));
      char *stub_name = IDENTIFIER_POINTER (TREE_PURPOSE (temp));
      char *sym;
      char *stub;

      if (! TREE_USED (temp))
        continue;

      STRIP_NAME_ENCODING (sym_name, sym_name);

      sym = alloca (strlen (sym_name) + 2);
      if (sym_name[0] == '*' || sym_name[0] == '&')
        strcpy (sym, sym_name + 1);
      else if (sym_name[0] == '-' || sym_name[0] == '+')
        strcpy (sym, sym_name);   
      else
        sym[0] = '_', strcpy (sym + 1, sym_name);

      stub = alloca (strlen (stub_name) + 2);
      if (stub_name[0] == '*' || stub_name[0] == '&')
        strcpy (stub, stub_name + 1);
      else
        stub[0] = '_', strcpy (stub + 1, stub_name);

      machopic_output_stub (asm_out_file, sym, stub);
    }

  for (temp = machopic_non_lazy_pointers;
       temp != NULL_TREE; 
       temp = TREE_CHAIN (temp))
    {
      char *sym_name = IDENTIFIER_POINTER (TREE_VALUE (temp));
      char *lazy_name = IDENTIFIER_POINTER (TREE_PURPOSE (temp));
#if 0
      tree decl = lookup_name_darwin (TREE_VALUE (temp));
#endif

      if (! TREE_USED (temp))
        continue;

      if (machopic_ident_defined_p (TREE_VALUE (temp))
#if 0 /* add back when we have private externs */
          || (decl && DECL_PRIVATE_EXTERN (decl))
#endif
          )
        {
          data_section ();
          assemble_align (UNITS_PER_WORD * BITS_PER_UNIT);
          assemble_label (lazy_name);
          assemble_integer (gen_rtx (SYMBOL_REF, Pmode, sym_name),
                            GET_MODE_SIZE (Pmode), 1);
        }
      else
        {
          machopic_nl_symbol_ptr_section ();
          assemble_name (asm_out_file, lazy_name); 
          fprintf (asm_out_file, ":\n");

          fprintf (asm_out_file, "\t.indirect_symbol ");
          assemble_name (asm_out_file, sym_name); 
          fprintf (asm_out_file, "\n");

          assemble_integer (const0_rtx, GET_MODE_SIZE (Pmode), 1);
        }
    }
}

int 
machopic_operand_p (op)
     rtx op;
{
  if (MACHOPIC_JUST_INDIRECT)
    {
      while (GET_CODE (op) == CONST)
        op = XEXP (op, 0);

      if (GET_CODE (op) == SYMBOL_REF)
        return machopic_name_defined_p (XSTR (op, 0));
      else
        return 0;
    }

  while (GET_CODE (op) == CONST)
    op = XEXP (op, 0);

  if (GET_CODE (op) == MINUS
      && GET_CODE (XEXP (op, 0)) == SYMBOL_REF
      && GET_CODE (XEXP (op, 1)) == SYMBOL_REF
      && machopic_name_defined_p (XSTR (XEXP (op, 0), 0))
      && machopic_name_defined_p (XSTR (XEXP (op, 1), 0)))
      return 1;

#if 0 /*def TARGET_TOC*/ /* i.e., PowerPC */
  /* Without this statement, the compiler crashes while compiling enquire.c
     when targetting PowerPC.  It is not known why this code is not needed
     when targetting other processors.  */
  else if (GET_CODE (op) == SYMBOL_REF
           && (machopic_classify_name (XSTR (op, 0))
               == MACHOPIC_DEFINED_FUNCTION))
    {
      return 1;
    }
#endif

  return 0;
}

/* This function records whether a given name corresponds to a defined
   or undefined function or variable, for machopic_classify_ident to
   use later.  */

void
darwin_encode_section_info (decl)
     tree decl;
{
  char code = '\0';
  int defined = 0;
  rtx sym_ref;
  char *orig_str, *new_str;
  size_t len, new_len;

  if ((TREE_CODE (decl) == FUNCTION_DECL
       || TREE_CODE (decl) == VAR_DECL)
      && ((TREE_STATIC (decl)
           && (!DECL_COMMON (decl) || !TREE_PUBLIC (decl)))
          || DECL_INITIAL (decl)))
    defined = 1;

  if (TREE_CODE (decl) == FUNCTION_DECL)
    code = (defined ? 'T' : 't');
  else if (TREE_CODE (decl) == VAR_DECL)
    code = (defined ? 'D' : 'd');

  if (code == '\0')
    return;

  sym_ref = XEXP (DECL_RTL (decl), 0);
  orig_str = XSTR (sym_ref, 0);
  len = strlen (orig_str) + 1;

  if (orig_str[0] == '!')
    {
      /* Already encoded; see if we need to change it.  */
      if (code == orig_str[1])
        return;
      /* Yes, tweak a copy of the name and put it in a new string.  */
      new_str = alloca (len);
      memcpy (new_str, orig_str, len);
      new_str[1] = code;
      XSTR (sym_ref, 0) = ggc_alloc_string (new_str, len);
      /* The non-lazy pointer list may have captured references to the
         old encoded name, change them.  */
      update_non_lazy_ptrs (XSTR (sym_ref, 0));
    }
  else
    {
      /* Add the encoding.  */
      new_len = len + 4;
      new_str = alloca (new_len);
      new_str[0] = '!';
      new_str[1] = code;
      new_str[2] = '_';
      new_str[3] = '_';
      memcpy (new_str + 4, orig_str, len);
      XSTR (sym_ref, 0) = ggc_alloc_string (new_str, new_len);
    }
}

/* Scan the list of non-lazy pointers and update any recorded names whose
   stripped name matches the argument.  */

static void
update_non_lazy_ptrs (name)
     const char *name;
{
  char *name1, *name2;
  tree temp;

  STRIP_NAME_ENCODING (name1, name);

  for (temp = machopic_non_lazy_pointers;
       temp != NULL_TREE; 
       temp = TREE_CHAIN (temp))
    {
      char *sym_name = IDENTIFIER_POINTER (TREE_VALUE (temp));

      if (*sym_name == '!')
        {
          STRIP_NAME_ENCODING (name2, sym_name);
          if (strcmp (name1, name2) == 0)
            {
              IDENTIFIER_POINTER (TREE_VALUE (temp)) = name;
              break;
            }
        }
    }
}