* as.h: Replace flagseen with separate variables.

[external/binutils.git] / gas / write.c

/* write.c - emit .o file
   Copyright (C) 1986, 87, 90, 91, 92, 93, 1994 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS 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.

   GAS 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 GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* This thing should be set up to do byteordering correctly.  But... */

#include "as.h"
#include "subsegs.h"
#include "obstack.h"
#include "output-file.h"

/* The NOP_OPCODE is for the alignment fill value.  Fill it with a nop
   instruction so that the disassembler does not choke on it.  */
#ifndef NOP_OPCODE
#define NOP_OPCODE 0x00
#endif

#ifndef TC_ADJUST_RELOC_COUNT
#define TC_ADJUST_RELOC_COUNT(FIXP,COUNT)
#endif

#ifndef TC_FORCE_RELOCATION
#define TC_FORCE_RELOCATION(FIXP) 0
#endif

#ifndef WORKING_DOT_WORD
extern CONST int md_short_jump_size;
extern CONST int md_long_jump_size;
#endif

int symbol_table_frozen;

#ifdef BFD_ASSEMBLER
/* We generally attach relocs to frag chains.  However, after we have
   chained these all together into a segment, any relocs we add after
   that must be attached to a segment.  This will include relocs added
   in md_estimate_size_for_relax, for example.  */
static int frags_chained = 0;
#endif

#ifndef BFD_ASSEMBLER

#ifndef MANY_SEGMENTS
struct frag *text_frag_root;
struct frag *data_frag_root;
struct frag *bss_frag_root;

struct frag *text_last_frag;    /* Last frag in segment. */
struct frag *data_last_frag;    /* Last frag in segment. */
static struct frag *bss_last_frag;      /* Last frag in segment. */
#endif

#ifndef BFD
static object_headers headers;
static char *the_object_file;
#endif

long string_byte_count;
char *next_object_file_charP;   /* Tracks object file bytes. */

#ifndef OBJ_VMS
int magic_number_for_object_file = DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE;
#endif

#endif /* BFD_ASSEMBLER */

#ifdef BFD_ASSEMBLER
static fixS *fix_new_internal PARAMS ((fragS *, int where, int size,
                                       symbolS *add, symbolS *sub,
                                       offsetT offset, int pcrel,
                                       bfd_reloc_code_real_type r_type));
#else
static fixS *fix_new_internal PARAMS ((fragS *, int where, int size,
                                       symbolS *add, symbolS *sub,
                                       offsetT offset, int pcrel,
                                       int r_type));
#endif
#if defined (BFD_ASSEMBLER) || !defined (BFD)
static long fixup_segment PARAMS ((fixS * fixP, segT this_segment_type));
#endif
static relax_addressT relax_align PARAMS ((relax_addressT addr, int align));

/*
 *                      fix_new()
 *
 * Create a fixS in obstack 'notes'.
 */
static fixS *
fix_new_internal (frag, where, size, add_symbol, sub_symbol, offset, pcrel,
                  r_type)
     fragS *frag;               /* Which frag? */
     int where;                 /* Where in that frag? */
     int size;                  /* 1, 2, or 4 usually. */
     symbolS *add_symbol;       /* X_add_symbol. */
     symbolS *sub_symbol;       /* X_op_symbol. */
     offsetT offset;            /* X_add_number. */
     int pcrel;                 /* TRUE if PC-relative relocation. */
#ifdef BFD_ASSEMBLER
     bfd_reloc_code_real_type r_type; /* Relocation type */
#else
     int r_type;                /* Relocation type */
#endif
{
  fixS *fixP;

  fixP = (fixS *) obstack_alloc (&notes, sizeof (fixS));

  fixP->fx_frag = frag;
  fixP->fx_where = where;
  fixP->fx_size = size;
  fixP->fx_addsy = add_symbol;
  fixP->fx_subsy = sub_symbol;
  fixP->fx_offset = offset;
  fixP->fx_pcrel = pcrel;
#if defined(NEED_FX_R_TYPE) || defined (BFD_ASSEMBLER)
  fixP->fx_r_type = r_type;
#endif
  fixP->fx_im_disp = 0;
  fixP->fx_pcrel_adjust = 0;
  fixP->fx_bit_fixP = 0;
  fixP->fx_addnumber = 0;
  fixP->tc_fix_data = NULL;
  fixP->fx_tcbit = 0;
  fixP->fx_done = 0;

#ifdef TC_something
  fixP->fx_bsr = 0;
#endif

  as_where (&fixP->fx_file, &fixP->fx_line);

  /* Usually, we want relocs sorted numerically, but while
     comparing to older versions of gas that have relocs
     reverse sorted, it is convenient to have this compile
     time option.  xoxorich. */

  {

#ifdef BFD_ASSEMBLER
    fixS **seg_fix_rootP = (frags_chained
                            ? &seg_info (now_seg)->fix_root
                            : &frchain_now->fix_root);
    fixS **seg_fix_tailP = (frags_chained
                            ? &seg_info (now_seg)->fix_tail
                            : &frchain_now->fix_tail);
#endif

#ifdef REVERSE_SORT_RELOCS

    fixP->fx_next = *seg_fix_rootP;
    *seg_fix_rootP = fixP;

#else /* REVERSE_SORT_RELOCS */

    fixP->fx_next = NULL;

    if (*seg_fix_tailP)
      (*seg_fix_tailP)->fx_next = fixP;
    else
      *seg_fix_rootP = fixP;
    *seg_fix_tailP = fixP;

#endif /* REVERSE_SORT_RELOCS */

  }

  return fixP;
}

/* Create a fixup relative to a symbol (plus a constant).  */

fixS *
fix_new (frag, where, size, add_symbol, offset, pcrel, r_type)
     fragS *frag;               /* Which frag? */
     int where;                 /* Where in that frag? */
     short int size;            /* 1, 2, or 4 usually. */
     symbolS *add_symbol;       /* X_add_symbol. */
     offsetT offset;            /* X_add_number. */
     int pcrel;                 /* TRUE if PC-relative relocation. */
#ifdef BFD_ASSEMBLER
     bfd_reloc_code_real_type r_type; /* Relocation type */
#else
     int r_type;                /* Relocation type */
#endif
{
  return fix_new_internal (frag, where, size, add_symbol,
                           (symbolS *) NULL, offset, pcrel, r_type);
}

/* Create a fixup for an expression.  Currently we only support fixups
   for difference expressions.  That is itself more than most object
   file formats support anyhow.  */

fixS *
fix_new_exp (frag, where, size, exp, pcrel, r_type)
     fragS *frag;               /* Which frag? */
     int where;                 /* Where in that frag? */
     short int size;            /* 1, 2, or 4 usually. */
     expressionS *exp;          /* Expression.  */
     int pcrel;                 /* TRUE if PC-relative relocation. */
#ifdef BFD_ASSEMBLER
     bfd_reloc_code_real_type r_type; /* Relocation type */
#else
     int r_type;                /* Relocation type */
#endif
{
  symbolS *add = NULL;
  symbolS *sub = NULL;
  offsetT off = 0;
  
  switch (exp->X_op)
    {
    case O_absent:
      break;

    case O_uminus:
      sub = exp->X_add_symbol;
      off = exp->X_add_number;
      break;

    case O_subtract:
      sub = exp->X_op_symbol;
      /* Fall through.  */
    case O_symbol:
      add = exp->X_add_symbol;
      /* Fall through.   */
    case O_constant:
      off = exp->X_add_number;
      break;
      
    default:
      as_bad ("expression too complex for fixup");
    }

  return fix_new_internal (frag, where, size, add, sub, off,
                           pcrel, r_type);
}

/* Append a string onto another string, bumping the pointer along.  */
void
append (charPP, fromP, length)
     char **charPP;
     char *fromP;
     unsigned long length;
{
  /* Don't trust memcpy() of 0 chars. */
  if (length == 0)
    return;

  memcpy (*charPP, fromP, length);
  *charPP += length;
}

#ifndef BFD_ASSEMBLER 
int section_alignment[SEG_MAXIMUM_ORDINAL];
#endif

/*
 * This routine records the largest alignment seen for each segment.
 * If the beginning of the segment is aligned on the worst-case
 * boundary, all of the other alignments within it will work.  At
 * least one object format really uses this info.
 */
void 
record_alignment (seg, align)
     /* Segment to which alignment pertains */
     segT seg;
     /* Alignment, as a power of 2 (e.g., 1 => 2-byte boundary, 2 => 4-byte
        boundary, etc.)  */
     int align;
{
#ifdef BFD_ASSEMBLER
  if (align > bfd_get_section_alignment (stdoutput, seg))
    bfd_set_section_alignment (stdoutput, seg, align);
#else
  if (align > section_alignment[(int) seg])
    section_alignment[(int) seg] = align;
#endif
}

#if defined (BFD_ASSEMBLER) || ! defined (BFD)

static fragS *
chain_frchains_together_1 (section, frchp)
     segT section;
     struct frchain *frchp;
{
  fragS dummy, *prev_frag = &dummy;
  fixS fix_dummy, *prev_fix = &fix_dummy;

  for (; frchp && frchp->frch_seg == section; frchp = frchp->frch_next)
    {
      prev_frag->fr_next = frchp->frch_root;
      prev_frag = frchp->frch_last;
#ifdef BFD_ASSEMBLER
      if (frchp->fix_root != (fixS *) NULL)
        {
          if (seg_info (section)->fix_root == (fixS *) NULL)
            seg_info (section)->fix_root = frchp->fix_root;
          prev_fix->fx_next = frchp->fix_root;
          seg_info (section)->fix_tail = frchp->fix_tail;
          prev_fix = frchp->fix_tail;
        }
#endif
    }
  prev_frag->fr_next = 0;
  return prev_frag;
}

#endif

#ifdef BFD_ASSEMBLER

static void
chain_frchains_together (abfd, section, xxx)
     bfd *abfd;                 /* unused */
     segT section;
     PTR xxx;                   /* unused */
{
  segment_info_type *info;

  /* BFD may have introduced its own sections without using
     subseg_new, so it is possible that seg_info is NULL.  */
  info = seg_info (section);
  if (info != (segment_info_type *) NULL)
   info->frchainP->frch_last
     = chain_frchains_together_1 (section, info->frchainP);

  /* Now that we've chained the frags together, we must add new fixups
     to the segment, not to the frag chain.  */
  frags_chained = 1;
}

#endif

#if !defined (BFD) && !defined (BFD_ASSEMBLER)

void 
remove_subsegs (head, seg, root, last)
     frchainS *head;
     int seg;
     fragS **root;
     fragS **last;
{
  *root = head->frch_root;
  *last = chain_frchains_together_1 (seg, head);
}

#endif /* BFD */

#if defined (BFD_ASSEMBLER) || !defined (BFD)

#ifdef BFD_ASSEMBLER
static void
cvt_frag_to_fill (sec, fragP)
     segT sec;
     fragS *fragP;
#else
static void
cvt_frag_to_fill (headers, fragP)
     object_headers *headers;
     fragS *fragP;
#endif
{
  switch (fragP->fr_type)
    {
    case rs_align:
    case rs_org:
#ifdef HANDLE_ALIGN
      HANDLE_ALIGN (fragP);
#endif
      fragP->fr_type = rs_fill;
      know (fragP->fr_next != NULL);
      fragP->fr_offset = (fragP->fr_next->fr_address
                          - fragP->fr_address
                          - fragP->fr_fix) / fragP->fr_var;
      break;

    case rs_fill:
      break;

    case rs_machine_dependent:
#ifdef BFD_ASSEMBLER
      md_convert_frag (stdoutput, sec, fragP);
#else
      md_convert_frag (headers, fragP);
#endif

      assert (fragP->fr_next == NULL || (fragP->fr_next->fr_address - fragP->fr_address == fragP->fr_fix));

      /*
       * After md_convert_frag, we make the frag into a ".space 0".
       * Md_convert_frag() should set up any fixSs and constants
       * required.
       */
      frag_wane (fragP);
      break;

#ifndef WORKING_DOT_WORD
    case rs_broken_word:
      {
        struct broken_word *lie;

        if (fragP->fr_subtype)
          {
            fragP->fr_fix += md_short_jump_size;
            for (lie = (struct broken_word *) (fragP->fr_symbol);
                 lie && lie->dispfrag == fragP;
                 lie = lie->next_broken_word)
              if (lie->added == 1)
                fragP->fr_fix += md_long_jump_size;
          }
        frag_wane (fragP);
      }
      break;
#endif

    default:
      BAD_CASE (fragP->fr_type);
      break;
    }
}

#endif /* defined (BFD_ASSEMBLER) || !defined (BFD) */

#ifdef BFD_ASSEMBLER
static void
relax_and_size_seg (abfd, sec, xxx)
     bfd *abfd;
     asection *sec;
     PTR xxx;
{
  flagword flags;
  fragS *fragp;
  segment_info_type *seginfo;
  int x;
  valueT size, newsize;

  flags = bfd_get_section_flags (abfd, sec);

  seginfo = (segment_info_type *) bfd_get_section_userdata (abfd, sec);
  if (seginfo && seginfo->frchainP)
    {
      relax_segment (seginfo->frchainP->frch_root, sec);
      for (fragp = seginfo->frchainP->frch_root; fragp; fragp = fragp->fr_next)
        cvt_frag_to_fill (sec, fragp);
      for (fragp = seginfo->frchainP->frch_root;
           fragp->fr_next;
           fragp = fragp->fr_next)
        /* walk to last elt */;
      size = fragp->fr_address + fragp->fr_fix;
    }
  else
    size = 0;

  if (size > 0 && ! seginfo->bss)
    flags |= SEC_HAS_CONTENTS;

  /* @@ This is just an approximation.  */
  if (seginfo && seginfo->fix_root)
    flags |= SEC_RELOC;
  else
    flags &= ~SEC_RELOC;
  x = bfd_set_section_flags (abfd, sec, flags);
  assert (x == true);

  newsize = md_section_align (sec, size);
  x = bfd_set_section_size (abfd, sec, newsize);
  assert (x == true);

  /* If the size had to be rounded up, add some padding in the last
     non-empty frag.  */
  assert (newsize >= size);
  if (size != newsize)
    {
      fragS *last = seginfo->frchainP->frch_last;
      fragp = seginfo->frchainP->frch_root;
      while (fragp->fr_next != last)
        fragp = fragp->fr_next;
      last->fr_address = size;
      fragp->fr_offset += newsize - size;
    }

#ifdef tc_frob_section
  tc_frob_section (sec);
#endif
#ifdef obj_frob_section
  obj_frob_section (sec);
#endif
}

#ifdef DEBUG2
static void
dump_section_relocs (abfd, sec, stream_)
     bfd *abfd;
     asection *sec;
     char *stream_;
{
  FILE *stream = (FILE *) stream_;
  segment_info_type *seginfo = seg_info (sec);
  fixS *fixp = seginfo->fix_root;

  if (!fixp)
    return;

  fprintf (stream, "sec %s relocs:\n", sec->name);
  while (fixp)
    {
      symbolS *s = fixp->fx_addsy;
      if (s)
        {
          fprintf (stream, "  %08x: %s(%s", fixp, S_GET_NAME (s),
                   s->bsym->section->name);
          if (s->bsym->flags & BSF_SECTION_SYM)
            {
              fprintf (stream, " section sym");
              if (S_GET_VALUE (s))
                fprintf (stream, "+%x", S_GET_VALUE (s));
            }
          else
            fprintf (stream, "+%x", S_GET_VALUE (s));
          fprintf (stream, ")+%x\n", fixp->fx_offset);
        }
      else
        fprintf (stream, "  %08x: type %d no sym\n", fixp, fixp->fx_r_type);
      fixp = fixp->fx_next;
    }
}
#else
#define dump_section_relocs(ABFD,SEC,STREAM)    (void)(ABFD,SEC,STREAM)
#endif

#ifndef EMIT_SECTION_SYMBOLS
#define EMIT_SECTION_SYMBOLS 1
#endif

static void
adjust_reloc_syms (abfd, sec, xxx)
     bfd *abfd;
     asection *sec;
     PTR xxx;
{
  segment_info_type *seginfo = seg_info (sec);
  fixS *fixp;

  if (seginfo == NULL)
    return;

  dump_section_relocs (abfd, sec, stderr);

  for (fixp = seginfo->fix_root; fixp; fixp = fixp->fx_next)
    if (fixp->fx_done)
      /* ignore it */;
    else if (fixp->fx_addsy)
      {
        symbolS *sym = fixp->fx_addsy;
        asection *symsec = sym->bsym->section;

        /* If it's one of these sections, assume the symbol is
           definitely going to be output.  The code in
           md_estimate_size_before_relax in tc-mips.c uses this test
           as well, so if you change this code you should look at that
           code.  */
        if (symsec == &bfd_und_section
            || symsec == &bfd_abs_section
            || bfd_is_com_section (symsec))
          {
            fixp->fx_addsy->sy_used_in_reloc = 1;
            continue;
          }

        /* Since we're reducing to section symbols, don't attempt to reduce
           anything that's already using one.  */
        if (sym->bsym->flags & BSF_SECTION_SYM)
          {
            fixp->fx_addsy->sy_used_in_reloc = 1;
            continue;
          }

        /* Is there some other reason we can't adjust this one?  (E.g.,
           call/bal links in i960-bout symbols.)  */
#ifdef obj_fix_adjustable
        if (! obj_fix_adjustable (fixp))
          {
            fixp->fx_addsy->sy_used_in_reloc = 1;
            continue;
          }
#endif

        /* Is there some other (target cpu dependent) reason we can't adjust
           this one?  (E.g. relocations involving function addresses on 
           the PA.  */
#ifdef tc_fix_adjustable
        if (! tc_fix_adjustable (fixp))
          {
            fixp->fx_addsy->sy_used_in_reloc = 1;
            continue;
          }
#endif

        /* If the section symbol isn't going to be output, the relocs
           at least should still work.  If not, figure out what to do
           when we run into that case.  */
        fixp->fx_offset += S_GET_VALUE (sym);
        if (sym->sy_frag)
          fixp->fx_offset += sym->sy_frag->fr_address;
        fixp->fx_addsy = section_symbol (symsec);
        fixp->fx_addsy->sy_used_in_reloc = 1;
      }
#if 1/*def RELOC_REQUIRES_SYMBOL*/
    else
      {
        /* There was no symbol required by this relocation.  However,
           BFD doesn't really handle relocations without symbols well.
           (At least, the COFF support doesn't.)  So for now we fake up
           a local symbol in the absolute section.  */

        fixp->fx_addsy = section_symbol (absolute_section);
        fixp->fx_addsy->sy_used_in_reloc = 1;
      }
#endif

  dump_section_relocs (abfd, sec, stderr);
}

static void
write_relocs (abfd, sec, xxx)
     bfd *abfd;
     asection *sec;
     PTR xxx;
{
  segment_info_type *seginfo = seg_info (sec);
  int i;
  unsigned int n;
  arelent **relocs;
  fixS *fixp;
  char *err;

  /* If seginfo is NULL, we did not create this section; don't do
     anything with it.  */
  if (seginfo == NULL)
    return;

  fixup_segment (seginfo->fix_root, sec);

  n = 0;
  for (fixp = seginfo->fix_root; fixp; fixp = fixp->fx_next)
    n++;

#ifndef RELOC_EXPANSION_POSSIBLE
  /* Set up reloc information as well.  */
  relocs = (arelent **) bfd_alloc_by_size_t (stdoutput,
                                             n * sizeof (arelent *));
  memset ((char*)relocs, 0, n * sizeof (arelent*));

  i = 0;
  for (fixp = seginfo->fix_root; fixp != (fixS *) NULL; fixp = fixp->fx_next)
    {
      arelent *reloc;
      char *data;
      bfd_reloc_status_type s;

      if (fixp->fx_done)
        {
          n--;
          continue;
        }
      reloc = tc_gen_reloc (sec, fixp);
      if (!reloc)
        {
          n--;
          continue;
        }
      data = fixp->fx_frag->fr_literal + fixp->fx_where;
      if (fixp->fx_where + fixp->fx_size
          > fixp->fx_frag->fr_fix + fixp->fx_frag->fr_offset)
        abort ();

      if (reloc->howto->partial_inplace == false
          && reloc->howto->pcrel_offset == true
          && reloc->howto->pc_relative == true)
        {
          /* bfd_perform_relocation screws this up */
          reloc->addend += reloc->address;
        }
      /* Pass bogus address so that when bfd_perform_relocation adds
         `reloc->address' back in, it'll come up with `data', which is where
         we want it to operate.  We can't just do it by fudging reloc->address,
         since that might be used in the calculations(?).  */
      s = bfd_perform_relocation (stdoutput, reloc, data - reloc->address,
                                  sec, stdoutput, &err);
      switch (s)
        {
        case bfd_reloc_ok:
          break;
        case bfd_reloc_overflow:
          as_bad_where (fixp->fx_file, fixp->fx_line, "relocation overflow");
          break;
        default:
          as_fatal ("bad return from bfd_perform_relocation");
        }
      relocs[i++] = reloc;
    }
#else
  n = n * MAX_RELOC_EXPANSION;
  /* Set up reloc information as well.  */
  relocs = (arelent **) bfd_alloc_by_size_t (stdoutput,
                                             n * sizeof (arelent *));

  i = 0;
  for (fixp = seginfo->fix_root; fixp != (fixS *) NULL; fixp = fixp->fx_next)
    {
      arelent **reloc;
      char *data;
      bfd_reloc_status_type s;
      int j;

      if (fixp->fx_done)
        {
          n--;
          continue;
        }
      reloc = tc_gen_reloc (sec, fixp);

      for (j = 0; reloc[j]; j++)
        {
          relocs[i++] = reloc[j];
          assert(i <= n);
        }
      data = fixp->fx_frag->fr_literal + fixp->fx_where;
      if (fixp->fx_where + fixp->fx_size
          > fixp->fx_frag->fr_fix + fixp->fx_frag->fr_offset)
        abort ();
      for (j = 0; reloc[j]; j++)
        {
          s = bfd_perform_relocation (stdoutput, reloc[j],
                                      data - reloc[0]->address,
                                      sec, stdoutput, &err);
          switch (s)
            {
            case bfd_reloc_ok:
              break;
            default:
              as_fatal ("bad return from bfd_perform_relocation");
            }
        }
    }
  n = i;
#endif

#ifdef DEBUG4
  {
    int i, j, nsyms;
    asymbol **sympp;
    sympp = bfd_get_outsymbols (stdoutput);
    nsyms = bfd_get_symcount (stdoutput);
    for (i = 0; i < n; i++)
      if (((*relocs[i]->sym_ptr_ptr)->flags & BSF_SECTION_SYM) == 0)
        {
          for (j = 0; j < nsyms; j++)
            if (sympp[j] == *relocs[i]->sym_ptr_ptr)
              break;
          if (j == nsyms)
            abort ();
        }
  }
#endif

  if (n)
    bfd_set_reloc (stdoutput, sec, relocs, n);
  else
    bfd_set_section_flags (abfd, sec,
                           (bfd_get_section_flags (abfd, sec)
                            & (flagword) ~SEC_RELOC));

#ifdef DEBUG3
  {
    int i;
    arelent *r;
    asymbol *s;
    fprintf (stderr, "relocs for sec %s\n", sec->name);
    for (i = 0; i < n; i++)
      {
        r = relocs[i];
        s = *r->sym_ptr_ptr;
        fprintf (stderr, "  reloc %2d @%08x off %4x : sym %-10s addend %x\n",
                 i, r, r->address, s->name, r->addend);
      }
  }
#endif
}

static void
write_contents (abfd, sec, xxx)
     bfd *abfd;
     asection *sec;
     PTR xxx;
{
  segment_info_type *seginfo = seg_info (sec);
  unsigned long offset = 0;
  fragS *f;

  /* Write out the frags.  */
  if (seginfo == NULL
      || ! (bfd_get_section_flags (abfd, sec) & SEC_HAS_CONTENTS))
    return;

  for (f = seginfo->frchainP->frch_root;
       f;
       f = f->fr_next)
    {
      int x;
      unsigned long fill_size;
      char *fill_literal;
      long count;

      assert (f->fr_type == rs_fill);
      if (f->fr_fix)
        {
          x = bfd_set_section_contents (stdoutput, sec,
                                        f->fr_literal, (file_ptr) offset,
                                        (bfd_size_type) f->fr_fix);
          if (x == false)
            {
              bfd_perror (stdoutput->filename);
              as_perror ("FATAL: Can't write %s", stdoutput->filename);
              exit (42);
            }
          offset += f->fr_fix;
        }
      fill_literal = f->fr_literal + f->fr_fix;
      fill_size = f->fr_var;
      count = f->fr_offset;
      assert (count >= 0);
      if (fill_size && count)
        while (count--)
          {
            x = bfd_set_section_contents (stdoutput, sec,
                                          fill_literal, (file_ptr) offset,
                                          (bfd_size_type) fill_size);
            if (x == false)
              {
                bfd_perror (stdoutput->filename);
                as_perror ("FATAL: Can't write %s", stdoutput->filename);
                exit (42);
              }
            offset += fill_size;
          }
    }
}
#endif

#if defined(BFD_ASSEMBLER) || (!defined (BFD) && !defined(OBJ_AOUT))
static void
merge_data_into_text ()
{
#if defined(BFD_ASSEMBLER) || defined(MANY_SEGMENTS)
  seg_info (text_section)->frchainP->frch_last->fr_next =
    seg_info (data_section)->frchainP->frch_root;
  seg_info (text_section)->frchainP->frch_last =
    seg_info (data_section)->frchainP->frch_last;
  seg_info (data_section)->frchainP = 0;
#else
  fixS *tmp;

  text_last_frag->fr_next = data_frag_root;
  text_last_frag = data_last_frag;
  data_last_frag = NULL;
  data_frag_root = NULL;
  if (text_fix_root)
    {
      for (tmp = text_fix_root; tmp->fx_next; tmp = tmp->fx_next);;
      tmp->fx_next = data_fix_root;
      text_fix_tail = data_fix_tail;
    }
  else
    text_fix_root = data_fix_root;
  data_fix_root = NULL;
#endif
}
#endif /* BFD_ASSEMBLER || (! BFD && ! OBJ_AOUT) */

#if !defined (BFD_ASSEMBLER) && !defined (BFD)
static void
relax_and_size_all_segments ()
{
  fragS *fragP;

  relax_segment (text_frag_root, SEG_TEXT);
  relax_segment (data_frag_root, SEG_DATA);
  relax_segment (bss_frag_root, SEG_BSS);
  /*
   * Now the addresses of frags are correct within the segment.
   */

  know (text_last_frag->fr_type == rs_fill && text_last_frag->fr_offset == 0);
  H_SET_TEXT_SIZE (&headers, text_last_frag->fr_address);
  text_last_frag->fr_address = H_GET_TEXT_SIZE (&headers);

  /*
   * Join the 2 segments into 1 huge segment.
   * To do this, re-compute every rn_address in the SEG_DATA frags.
   * Then join the data frags after the text frags.
   *
   * Determine a_data [length of data segment].
   */
  if (data_frag_root)
    {
      register relax_addressT slide;

      know ((text_last_frag->fr_type == rs_fill) && (text_last_frag->fr_offset == 0));

      H_SET_DATA_SIZE (&headers, data_last_frag->fr_address);
      data_last_frag->fr_address = H_GET_DATA_SIZE (&headers);
      slide = H_GET_TEXT_SIZE (&headers);       /* & in file of the data segment. */
#ifdef OBJ_BOUT
#define RoundUp(N,S) (((N)+(S)-1)&-(S))
      /* For b.out: If the data section has a strict alignment
         requirement, its load address in the .o file will be
         rounded up from the size of the text section.  These
         two values are *not* the same!  Similarly for the bss
         section....  */
      slide = RoundUp (slide, 1 << section_alignment[SEG_DATA]);
#endif

      for (fragP = data_frag_root; fragP; fragP = fragP->fr_next)
        {
          fragP->fr_address += slide;
        }                       /* for each data frag */

      know (text_last_frag != 0);
      text_last_frag->fr_next = data_frag_root;
    }
  else
    {
      H_SET_DATA_SIZE (&headers, 0);
    }

#ifdef OBJ_BOUT
  /* See above comments on b.out data section address.  */
  {
    long bss_vma;
    if (data_last_frag == 0)
      bss_vma = H_GET_TEXT_SIZE (&headers);
    else
      bss_vma = data_last_frag->fr_address;
    bss_vma = RoundUp (bss_vma, 1 << section_alignment[SEG_BSS]);
    bss_address_frag.fr_address = bss_vma;
  }
#else /* ! OBJ_BOUT */
  bss_address_frag.fr_address = (H_GET_TEXT_SIZE (&headers) +
                                 H_GET_DATA_SIZE (&headers));

#endif /* ! OBJ_BOUT */

  /* Slide all the frags */
  if (bss_frag_root)
    {
      relax_addressT slide = bss_address_frag.fr_address;

      for (fragP = bss_frag_root; fragP; fragP = fragP->fr_next)
        {
          fragP->fr_address += slide;
        }                       /* for each bss frag */
    }

  if (bss_last_frag)
    H_SET_BSS_SIZE (&headers,
                    bss_last_frag->fr_address - bss_frag_root->fr_address);
  else
    H_SET_BSS_SIZE (&headers, 0);
}
#endif /* ! BFD_ASSEMBLER && ! BFD */

#if defined (BFD_ASSEMBLER) || !defined (BFD)

#ifdef BFD_ASSEMBLER
static void
set_symtab ()
{
  int nsyms;
  asymbol **asympp;
  symbolS *symp;
  boolean result;
  extern PTR bfd_alloc PARAMS ((bfd *, size_t));

  /* Count symbols.  We can't rely on a count made by the loop in
     write_object_file, because *_frob_file may add a new symbol or
     two.  */
  nsyms = 0;
  for (symp = symbol_rootP; symp; symp = symbol_next (symp))
    nsyms++;

  if (nsyms)
    {
      int i;

      asympp = (asymbol **) bfd_alloc (stdoutput,
                                       nsyms * sizeof (asymbol *));
      symp = symbol_rootP;
      for (i = 0; i < nsyms; i++, symp = symbol_next (symp))
        {
          asympp[i] = symp->bsym;
          symp->written = 1;
        }
    }
  else
    asympp = 0;
  result = bfd_set_symtab (stdoutput, asympp, nsyms);
  assert (result == true);
  symbol_table_frozen = 1;
}
#endif

void 
write_object_file ()
{
  struct frchain *frchainP;     /* Track along all frchains. */
#if ! defined (BFD_ASSEMBLER) || ! defined (WORKING_DOT_WORD)
  fragS *fragP;                 /* Track along all frags. */
#endif

  /* Do we really want to write it?  */
  {
    int n_warns, n_errs;
    n_warns = had_warnings ();
    n_errs = had_errors ();
    /* The -Z flag indicates that an object file should be generated,
       regardless of warnings and errors.  */
    if (flag_always_generate_output)
      {
        if (n_warns || n_errs)
          as_warn ("%d error%s, %d warning%s, generating bad object file.\n",
                   n_errs, n_errs == 1 ? "" : "s",
                   n_warns, n_warns == 1 ? "" : "s");
      }
    else
      {
        if (n_errs)
          as_fatal ("%d error%s, %d warning%s, no object file generated.\n",
                    n_errs, n_errs == 1 ? "" : "s",
                    n_warns, n_warns == 1 ? "" : "s");
      }
  }

#ifdef  OBJ_VMS
  /* Under VMS we try to be compatible with VAX-11 "C".  Thus, we call
     a routine to check for the definition of the procedure "_main",
     and if so -- fix it up so that it can be program entry point. */
  VMS_Check_For_Main ();
#endif /* VMS */

  /* After every sub-segment, we fake an ".align ...". This conforms to
     BSD4.2 brane-damage. We then fake ".fill 0" because that is the kind of
     frag that requires least thought. ".align" frags like to have a
     following frag since that makes calculating their intended length
     trivial.

     @@ Is this really necessary??  */
#ifndef SUB_SEGMENT_ALIGN
#ifdef BFD_ASSEMBLER
#define SUB_SEGMENT_ALIGN(SEG) (0)
#else
#define SUB_SEGMENT_ALIGN(SEG) (2)
#endif
#endif
  for (frchainP = frchain_root; frchainP; frchainP = frchainP->frch_next)
    {
      subseg_set (frchainP->frch_seg, frchainP->frch_subseg);
      frag_align (SUB_SEGMENT_ALIGN (now_seg), NOP_OPCODE);
      /* frag_align will have left a new frag.
         Use this last frag for an empty ".fill".

         For this segment ...
         Create a last frag. Do not leave a "being filled in frag".  */
      frag_wane (frag_now);
      frag_now->fr_fix = 0;
      know (frag_now->fr_next == NULL);
    }

  /* From now on, we don't care about sub-segments.  Build one frag chain
     for each segment. Linked thru fr_next.  */

#ifdef BFD_ASSEMBLER
  /* Remove the sections created by gas for its own purposes.  */
  {
    asection **seclist, *sec;
    seclist = &stdoutput->sections;
    while (seclist && *seclist)
      {
        sec = *seclist;
        while (sec == reg_section || sec == expr_section)
          {
            sec = sec->next;
            *seclist = sec;
            stdoutput->section_count--;
            if (!sec)
              break;
          }
        if (*seclist)
          seclist = &(*seclist)->next;
      }
  }

  bfd_map_over_sections (stdoutput, chain_frchains_together, (char *) 0);
#else
  remove_subsegs (frchain_root, SEG_TEXT, &text_frag_root, &text_last_frag);
  remove_subsegs (data0_frchainP, SEG_DATA, &data_frag_root, &data_last_frag);
  remove_subsegs (bss0_frchainP, SEG_BSS, &bss_frag_root, &bss_last_frag);
#endif

  /* We have two segments. If user gave -R flag, then we must put the
     data frags into the text segment. Do this before relaxing so
     we know to take advantage of -R and make shorter addresses.  */
#if !defined (OBJ_AOUT) || defined (BFD_ASSEMBLER)
  if (flag_readonly_data_in_text)
    {
      merge_data_into_text ();
    }
#endif

#ifdef BFD_ASSEMBLER
  bfd_map_over_sections (stdoutput, relax_and_size_seg, (char *) 0);
#else
  relax_and_size_all_segments ();
#endif /* BFD_ASSEMBLER */

#ifndef BFD_ASSEMBLER
  /*
   *
   * Crawl the symbol chain.
   *
   * For each symbol whose value depends on a frag, take the address of
   * that frag and subsume it into the value of the symbol.
   * After this, there is just one way to lookup a symbol value.
   * Values are left in their final state for object file emission.
   * We adjust the values of 'L' local symbols, even if we do
   * not intend to emit them to the object file, because their values
   * are needed for fix-ups.
   *
   * Unless we saw a -L flag, remove all symbols that begin with 'L'
   * from the symbol chain.  (They are still pointed to by the fixes.)
   *
   * Count the remaining symbols.
   * Assign a symbol number to each symbol.
   * Count the number of string-table chars we will emit.
   * Put this info into the headers as appropriate.
   *
   */
  know (zero_address_frag.fr_address == 0);
  string_byte_count = sizeof (string_byte_count);

  obj_crawl_symbol_chain (&headers);

  if (string_byte_count == sizeof (string_byte_count))
    string_byte_count = 0;

  H_SET_STRING_SIZE (&headers, string_byte_count);

  /*
   * Addresses of frags now reflect addresses we use in the object file.
   * Symbol values are correct.
   * Scan the frags, converting any ".org"s and ".align"s to ".fill"s.
   * Also converting any machine-dependent frags using md_convert_frag();
   */
  subseg_change (SEG_TEXT, 0);

  for (fragP = text_frag_root; fragP; fragP = fragP->fr_next)
    {
      cvt_frag_to_fill (&headers, fragP);

      /* Some assert macros don't work with # directives mixed in.  */
#ifndef NDEBUG
      if (!(fragP->fr_next == NULL
#ifdef OBJ_BOUT
            || fragP->fr_next == data_frag_root
#endif
            || ((fragP->fr_next->fr_address - fragP->fr_address)
                == (fragP->fr_fix + fragP->fr_offset * fragP->fr_var))))
        abort ();
#endif
    }
#endif /* ! BFD_ASSEMBLER */

#ifndef WORKING_DOT_WORD
  {
    struct broken_word *lie;
    struct broken_word **prevP;

    prevP = &broken_words;
    for (lie = broken_words; lie; lie = lie->next_broken_word)
      if (!lie->added)
        {
          expressionS exp;

          exp.X_op = O_subtract;
          exp.X_add_symbol = lie->add;
          exp.X_op_symbol = lie->sub;
          exp.X_add_number = lie->addnum;
#ifdef BFD_ASSEMBLER
          fix_new_exp (lie->frag,
                       lie->word_goes_here - lie->frag->fr_literal,
                       2, &exp, 0, BFD_RELOC_NONE);
#else
#if defined(TC_SPARC) || defined(TC_A29K) || defined(NEED_FX_R_TYPE)
          fix_new_exp (lie->frag,
                       lie->word_goes_here - lie->frag->fr_literal,
                       2, &exp, 0, NO_RELOC);
#else
#ifdef TC_NS32K
          fix_new_ns32k_exp (lie->frag,
                             lie->word_goes_here - lie->frag->fr_literal,
                             2, &exp, 0, 0, 2, 0, 0);
#else
          fix_new_exp (lie->frag,
                       lie->word_goes_here - lie->frag->fr_literal,
                       2, &exp, 0, 0);
#endif /* TC_NS32K */
#endif /* TC_SPARC|TC_A29K|NEED_FX_R_TYPE */
#endif /* BFD_ASSEMBLER */
          *prevP = lie->next_broken_word;
        }
      else
        prevP = &(lie->next_broken_word);

    for (lie = broken_words; lie;)
      {
        struct broken_word *untruth;
        char *table_ptr;
        addressT table_addr;
        addressT from_addr, to_addr;
        int n, m;

        fragP = lie->dispfrag;

        /* Find out how many broken_words go here.  */
        n = 0;
        for (untruth = lie; untruth && untruth->dispfrag == fragP; untruth = untruth->next_broken_word)
          if (untruth->added == 1)
            n++;

        table_ptr = lie->dispfrag->fr_opcode;
        table_addr = lie->dispfrag->fr_address + (table_ptr - lie->dispfrag->fr_literal);
        /* Create the jump around the long jumps.  This is a short
           jump from table_ptr+0 to table_ptr+n*long_jump_size.  */
        from_addr = table_addr;
        to_addr = table_addr + md_short_jump_size + n * md_long_jump_size;
        md_create_short_jump (table_ptr, from_addr, to_addr, lie->dispfrag, lie->add);
        table_ptr += md_short_jump_size;
        table_addr += md_short_jump_size;

        for (m = 0; lie && lie->dispfrag == fragP; m++, lie = lie->next_broken_word)
          {
            if (lie->added == 2)
              continue;
            /* Patch the jump table */
            /* This is the offset from ??? to table_ptr+0 */
            to_addr = table_addr - S_GET_VALUE (lie->sub);
            md_number_to_chars (lie->word_goes_here, to_addr, 2);
            for (untruth = lie->next_broken_word; untruth && untruth->dispfrag == fragP; untruth = untruth->next_broken_word)
              {
                if (untruth->use_jump == lie)
                  md_number_to_chars (untruth->word_goes_here, to_addr, 2);
              }

            /* Install the long jump */
            /* this is a long jump from table_ptr+0 to the final target */
            from_addr = table_addr;
            to_addr = S_GET_VALUE (lie->add) + lie->addnum;
            md_create_long_jump (table_ptr, from_addr, to_addr, lie->dispfrag, lie->add);
            table_ptr += md_long_jump_size;
            table_addr += md_long_jump_size;
          }
      }
  }
#endif /* not WORKING_DOT_WORD */

#ifndef BFD_ASSEMBLER
#ifndef OBJ_VMS
  {                             /* not vms */
    long object_file_size;
    /*
     * Scan every FixS performing fixups. We had to wait until now to do
     * this because md_convert_frag() may have made some fixSs.
     */
    int trsize, drsize;

    subseg_change (SEG_TEXT, 0);
    trsize = md_reloc_size * fixup_segment (text_fix_root, SEG_TEXT);
    subseg_change (SEG_DATA, 0);
    drsize = md_reloc_size * fixup_segment (data_fix_root, SEG_DATA);
    H_SET_RELOCATION_SIZE (&headers, trsize, drsize);

    /* FIXME move this stuff into the pre-write-hook */
    H_SET_MAGIC_NUMBER (&headers, magic_number_for_object_file);
    H_SET_ENTRY_POINT (&headers, 0);

    obj_pre_write_hook (&headers);      /* extra coff stuff */

    object_file_size = H_GET_FILE_SIZE (&headers);
    next_object_file_charP = the_object_file = xmalloc (object_file_size);

    output_file_create (out_file_name);

    obj_header_append (&next_object_file_charP, &headers);

    know ((next_object_file_charP - the_object_file) == H_GET_HEADER_SIZE (&headers));

    /*
     * Emit code.
     */
    for (fragP = text_frag_root; fragP; fragP = fragP->fr_next)
      {
        register long count;
        register char *fill_literal;
        register long fill_size;

        know (fragP->fr_type == rs_fill);
        append (&next_object_file_charP, fragP->fr_literal, (unsigned long) fragP->fr_fix);
        fill_literal = fragP->fr_literal + fragP->fr_fix;
        fill_size = fragP->fr_var;
        know (fragP->fr_offset >= 0);

        for (count = fragP->fr_offset; count; count--)
          {
            append (&next_object_file_charP, fill_literal, (unsigned long) fill_size);
          }                     /* for each  */

      }                         /* for each code frag. */

    know ((next_object_file_charP - the_object_file) == (H_GET_HEADER_SIZE (&headers) + H_GET_TEXT_SIZE (&headers) + H_GET_DATA_SIZE (&headers)));

    /*
     * Emit relocations.
     */
    obj_emit_relocations (&next_object_file_charP, text_fix_root, (relax_addressT) 0);
    know ((next_object_file_charP - the_object_file) == (H_GET_HEADER_SIZE (&headers) + H_GET_TEXT_SIZE (&headers) + H_GET_DATA_SIZE (&headers) + H_GET_TEXT_RELOCATION_SIZE (&headers)));
#ifdef TC_I960
    /* Make addresses in data relocation directives relative to beginning of
     * first data fragment, not end of last text fragment:  alignment of the
     * start of the data segment may place a gap between the segments.
     */
    obj_emit_relocations (&next_object_file_charP, data_fix_root, data0_frchainP->frch_root->fr_address);
#else /* TC_I960 */
    obj_emit_relocations (&next_object_file_charP, data_fix_root, text_last_frag->fr_address);
#endif /* TC_I960 */

    know ((next_object_file_charP - the_object_file) == (H_GET_HEADER_SIZE (&headers) + H_GET_TEXT_SIZE (&headers) + H_GET_DATA_SIZE (&headers) + H_GET_TEXT_RELOCATION_SIZE (&headers) + H_GET_DATA_RELOCATION_SIZE (&headers)));

    /*
     * Emit line number entries.
     */
    OBJ_EMIT_LINENO (&next_object_file_charP, lineno_rootP, the_object_file);
    know ((next_object_file_charP - the_object_file) == (H_GET_HEADER_SIZE (&headers) + H_GET_TEXT_SIZE (&headers) + H_GET_DATA_SIZE (&headers) + H_GET_TEXT_RELOCATION_SIZE (&headers) + H_GET_DATA_RELOCATION_SIZE (&headers) + H_GET_LINENO_SIZE (&headers)));

    /*
     * Emit symbols.
     */
    obj_emit_symbols (&next_object_file_charP, symbol_rootP);
    know ((next_object_file_charP - the_object_file) == (H_GET_HEADER_SIZE (&headers) + H_GET_TEXT_SIZE (&headers) + H_GET_DATA_SIZE (&headers) + H_GET_TEXT_RELOCATION_SIZE (&headers) + H_GET_DATA_RELOCATION_SIZE (&headers) + H_GET_LINENO_SIZE (&headers) + H_GET_SYMBOL_TABLE_SIZE (&headers)));

    /*
     * Emit strings.
     */

    if (string_byte_count > 0)
      {
        obj_emit_strings (&next_object_file_charP);
      }                         /* only if we have a string table */

#ifdef BFD_HEADERS
    bfd_seek (stdoutput, 0, 0);
    bfd_write (the_object_file, 1, object_file_size, stdoutput);
#else

    /* Write the data to the file */
    output_file_append (the_object_file, object_file_size, out_file_name);
#endif
  }                             /* non vms output */
#else /* VMS */
  /*
   *    Now do the VMS-dependent part of writing the object file
   */
  VMS_write_object_file (H_GET_TEXT_SIZE (&headers),
                         H_GET_DATA_SIZE (&headers),
                         H_GET_BSS_SIZE (&headers),
                         text_frag_root, data_frag_root);
#endif /* VMS */
#else /* BFD_ASSEMBLER */

  bfd_map_over_sections (stdoutput, adjust_reloc_syms, (char *)0);

  /* Set up symbol table, and write it out.  */
  if (symbol_rootP)
    {
      symbolS *symp;

      for (symp = symbol_rootP; symp; symp = symbol_next (symp))
        {
          int punt = 0;

          if (! symp->sy_resolved)
            {
              if (symp->sy_value.X_op == O_constant)
                {
                  /* This is the normal case; skip the call.  */
                  S_SET_VALUE (symp,
                               (S_GET_VALUE (symp)
                                + symp->sy_frag->fr_address));
                  symp->sy_resolved = 1;
                }
              else
                resolve_symbol_value (symp);
            }

          /* So far, common symbols have been treated like undefined symbols.
             Put them in the common section now.  */
          if (S_IS_DEFINED (symp) == 0
              && S_GET_VALUE (symp) != 0)
            S_SET_SEGMENT (symp, &bfd_com_section);
#if 0
          printf ("symbol `%s'\n\t@%x: value=%d flags=%x seg=%s\n",
                  S_GET_NAME (symp), symp,
                  S_GET_VALUE (symp),
                  symp->bsym->flags,
                  segment_name (symp->bsym->section));
#endif

#ifdef obj_frob_symbol
          obj_frob_symbol (symp, punt);
#endif
#ifdef tc_frob_symbol
          if (! punt || symp->sy_used_in_reloc)
            tc_frob_symbol (symp, punt);
#endif

          /* If we don't want to keep this symbol, splice it out of
             the chain now.  If EMIT_SECTION_SYMBOLS is 0, we never
             want section symbols.  Otherwise, we skip local symbols
             and symbols that the frob_symbol macros told us to punt,
             but we keep such symbols if they are used in relocs.  */
          if ((! EMIT_SECTION_SYMBOLS
               && (symp->bsym->flags & BSF_SECTION_SYM) != 0)
              /* Note that S_IS_EXTERN and S_IS_LOCAL are not always
                 opposites.  Sometimes the former checks flags and the
                 latter examines the name...  */
              || (!S_IS_EXTERN (symp)
                  && (S_IS_LOCAL (symp) || punt)
                  && ! symp->sy_used_in_reloc))
            {
              symbol_remove (symp, &symbol_rootP, &symbol_lastP);
              /* After symbol_remove, symbol_next(symp) still returns
                 the one that came after it in the chain.  So we don't
                 need to do any extra cleanup work here.  */

              continue;
            }

          /* Make sure we really got a value for the symbol.  */
          if (! symp->sy_resolved)
            {
              as_bad ("can't resolve value for symbol \"%s\"",
                      S_GET_NAME (symp));
              symp->sy_resolved = 1;
            }

          /* Set the value into the BFD symbol.  Up til now the value
             has only been kept in the gas symbolS struct.  */
          symp->bsym->value = S_GET_VALUE (symp);
        }
    }

  /* Now do any format-specific adjustments to the symbol table, such
     as adding file symbols.  */
#ifdef obj_adjust_symtab
  obj_adjust_symtab ();
#endif

  /* Now that all the sizes are known, and contents correct, we can
     start writing to the file.  */
  set_symtab ();

  /* If *_frob_file changes the symbol value at this point, it is
     responsible for moving the changed value into symp->bsym->value
     as well.  Hopefully all symbol value changing can be done in
     *_frob_symbol.  */
#ifdef tc_frob_file
  tc_frob_file ();
#endif
#ifdef obj_frob_file
  obj_frob_file ();
#endif

  bfd_map_over_sections (stdoutput, write_relocs, (char *) 0);

  bfd_map_over_sections (stdoutput, write_contents, (char *) 0);
#endif /* BFD_ASSEMBLER */
}
#endif /* ! BFD */

/*
 *                      relax_segment()
 *
 * Now we have a segment, not a crowd of sub-segments, we can make fr_address
 * values.
 *
 * Relax the frags.
 *
 * After this, all frags in this segment have addresses that are correct
 * within the segment. Since segments live in different file addresses,
 * these frag addresses may not be the same as final object-file addresses.
 */

#ifndef md_relax_frag

/* Subroutines of relax_segment.  */
static int 
is_dnrange (f1, f2)
     struct frag *f1;
     struct frag *f2;
{
  for (; f1; f1 = f1->fr_next)
    if (f1->fr_next == f2)
      return 1;
  return 0;
}

#endif /* ! defined (md_relax_frag) */

/* Relax_align. Advance location counter to next address that has 'alignment'
   lowest order bits all 0s, return size of adjustment made.  */
static relax_addressT
relax_align (address, alignment)
     register relax_addressT address;   /* Address now. */
     register int alignment;    /* Alignment (binary). */
{
  relax_addressT mask;
  relax_addressT new_address;

  mask = ~((~0) << alignment);
  new_address = (address + mask) & (~mask);
  if (linkrelax)
    /* We must provide lots of padding, so the linker can discard it
       when needed.  The linker will not add extra space, ever.  */
    new_address += (1 << alignment);
  return (new_address - address);
}

void 
relax_segment (segment_frag_root, segment)
     struct frag *segment_frag_root;
     segT segment;
{
  register struct frag *fragP;
  register relax_addressT address;
#if !defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
  know (segment == SEG_DATA || segment == SEG_TEXT || segment == SEG_BSS);
#endif
  /* In case md_estimate_size_before_relax() wants to make fixSs. */
  subseg_change (segment, 0);

  /* For each frag in segment: count and store  (a 1st guess of)
     fr_address.  */
  address = 0;
  for (fragP = segment_frag_root; fragP; fragP = fragP->fr_next)
    {
      fragP->fr_address = address;
      address += fragP->fr_fix;

      switch (fragP->fr_type)
        {
        case rs_fill:
          address += fragP->fr_offset * fragP->fr_var;
          break;

        case rs_align:
          {
            int offset = relax_align (address, (int) fragP->fr_offset);
            if (offset % fragP->fr_var != 0)
              {
                as_bad ("alignment padding (%d bytes) not a multiple of %ld",
                        offset, (long) fragP->fr_var);
                offset -= (offset % fragP->fr_var);
              }
            address += offset;
          }
          break;

        case rs_org:
          /* Assume .org is nugatory. It will grow with 1st relax.  */
          break;

        case rs_machine_dependent:
          address += md_estimate_size_before_relax (fragP, segment);
          break;

#ifndef WORKING_DOT_WORD
          /* Broken words don't concern us yet */
        case rs_broken_word:
          break;
#endif

        default:
          BAD_CASE (fragP->fr_type);
          break;
        }                       /* switch(fr_type) */
    }                           /* for each frag in the segment */

  /* Do relax().  */
  {
    long stretch;       /* May be any size, 0 or negative. */
    /* Cumulative number of addresses we have */
    /* relaxed this pass. */
    /* We may have relaxed more than one address. */
    long stretched;     /* Have we stretched on this pass? */
    /* This is 'cuz stretch may be zero, when, in fact some piece of code
       grew, and another shrank.  If a branch instruction doesn't fit anymore,
       we could be scrod.  */

    do
      {
        stretch = stretched = 0;
        for (fragP = segment_frag_root; fragP; fragP = fragP->fr_next)
          {
            long growth = 0;
            unsigned long was_address;
            long offset;
            symbolS *symbolP;
            long target;
            long after;

            was_address = fragP->fr_address;
            address = fragP->fr_address += stretch;
            symbolP = fragP->fr_symbol;
            offset = fragP->fr_offset;

            switch (fragP->fr_type)
              {
              case rs_fill:     /* .fill never relaxes. */
                growth = 0;
                break;

#ifndef WORKING_DOT_WORD
                /* JF:  This is RMS's idea.  I do *NOT* want to be blamed
                   for it I do not want to write it.  I do not want to have
                   anything to do with it.  This is not the proper way to
                   implement this misfeature.  */
              case rs_broken_word:
                {
                  struct broken_word *lie;
                  struct broken_word *untruth;

                  /* Yes this is ugly (storing the broken_word pointer
                     in the symbol slot).  Still, this whole chunk of
                     code is ugly, and I don't feel like doing anything
                     about it.  Think of it as stubbornness in action.  */
                  growth = 0;
                  for (lie = (struct broken_word *) (fragP->fr_symbol);
                       lie && lie->dispfrag == fragP;
                       lie = lie->next_broken_word)
                    {

                      if (lie->added)
                        continue;

                      offset = (lie->add->sy_frag->fr_address
                                + S_GET_VALUE (lie->add)
                                + lie->addnum
                                - (lie->sub->sy_frag->fr_address
                                   + S_GET_VALUE (lie->sub)));
                      if (offset <= -32768 || offset >= 32767)
                        {
                          if (flag_warn_displacement)
                            {
                              char buf[50];
                              sprint_value (buf, (addressT) lie->addnum);
                              as_warn (".word %s-%s+%s didn't fit",
                                       S_GET_NAME (lie->add),
                                       S_GET_NAME (lie->sub),
                                       buf);
                            }
                          lie->added = 1;
                          if (fragP->fr_subtype == 0)
                            {
                              fragP->fr_subtype++;
                              growth += md_short_jump_size;
                            }
                          for (untruth = lie->next_broken_word;
                               untruth && untruth->dispfrag == lie->dispfrag;
                               untruth = untruth->next_broken_word)
                            if ((untruth->add->sy_frag == lie->add->sy_frag)
                                && S_GET_VALUE (untruth->add) == S_GET_VALUE (lie->add))
                              {
                                untruth->added = 2;
                                untruth->use_jump = lie;
                              }
                          growth += md_long_jump_size;
                        }
                    }

                  break;
                }               /* case rs_broken_word */
#endif
              case rs_align:
                growth = (relax_align ((relax_addressT) (address
                                                         + fragP->fr_fix),
                                       (int) offset)
                          - relax_align ((relax_addressT) (was_address
                                                           + fragP->fr_fix),
                                         (int) offset));
                break;

              case rs_org:
                target = offset;

                if (symbolP)
                  {
#if !defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
                    know ((S_GET_SEGMENT (symbolP) == SEG_ABSOLUTE)
                          || (S_GET_SEGMENT (symbolP) == SEG_DATA)
                          || (S_GET_SEGMENT (symbolP) == SEG_TEXT)
                          || S_GET_SEGMENT (symbolP) == SEG_BSS);
                    know (symbolP->sy_frag);
                    know (!(S_GET_SEGMENT (symbolP) == SEG_ABSOLUTE)
                          || (symbolP->sy_frag == &zero_address_frag));
#endif
                    target += S_GET_VALUE (symbolP)
                      + symbolP->sy_frag->fr_address;
                  }             /* if we have a symbol */

                know (fragP->fr_next);
                after = fragP->fr_next->fr_address;
                growth = ((target - after) > 0) ? (target - after) : 0;
                /* Growth may be negative, but variable part of frag
                   cannot have fewer than 0 chars.  That is, we can't
                   .org backwards. */

                growth -= stretch;      /* This is an absolute growth factor */
                break;

              case rs_machine_dependent:
#ifdef md_relax_frag
                growth = md_relax_frag (fragP, stretch);
#else
                /* The default way to relax a frag is to look through
                   md_relax_table.  */
                {
                  const relax_typeS *this_type;
                  const relax_typeS *start_type;
                  relax_substateT next_state;
                  relax_substateT this_state;
                  long aim;

                  this_state = fragP->fr_subtype;
                  start_type = this_type = md_relax_table + this_state;
                  target = offset;

                  if (symbolP)
                    {
#ifndef DIFF_EXPR_OK
#if !defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
                      know ((S_GET_SEGMENT (symbolP) == SEG_ABSOLUTE)
                            || (S_GET_SEGMENT (symbolP) == SEG_DATA)
                            || (S_GET_SEGMENT (symbolP) == SEG_BSS)
                            || (S_GET_SEGMENT (symbolP) == SEG_TEXT));
#endif
                      know (symbolP->sy_frag);
#endif
                      know (!(S_GET_SEGMENT (symbolP) == absolute_section)
                            || symbolP->sy_frag == &zero_address_frag);
                      target +=
                        S_GET_VALUE (symbolP)
                        + symbolP->sy_frag->fr_address;

                      /* If frag has yet to be reached on this pass,
                         assume it will move by STRETCH just as we did.
                         If this is not so, it will be because some frag
                         between grows, and that will force another pass.

                         Beware zero-length frags.

                         There should be a faster way to do this.  */

                      if (symbolP->sy_frag->fr_address >= was_address
                          && is_dnrange (fragP, symbolP->sy_frag))
                        {
                          target += stretch;
                        }
                    }

                  aim = target - address - fragP->fr_fix;
                  /* The displacement is affected by the instruction size
                     for the 32k architecture. I think we ought to be able
                     to add fragP->fr_pcrel_adjust in all cases (it should be
                     zero if not used), but just in case it breaks something
                     else we'll put this inside #ifdef NS32K ... #endif  */
#ifndef TC_NS32K
                  if (fragP->fr_pcrel_adjust)
                    abort ();
#endif
                  aim += fragP->fr_pcrel_adjust;

                  if (aim < 0)
                    {
                      /* Look backwards. */
                      for (next_state = this_type->rlx_more; next_state;)
                        if (aim >= this_type->rlx_backward)
                          next_state = 0;
                        else
                          {
                            /* Grow to next state. */
                            this_state = next_state;
                            this_type = md_relax_table + this_state;
                            next_state = this_type->rlx_more;
                          }
                    }
                  else
                    {
#ifdef M68K_AIM_KLUDGE
                      M68K_AIM_KLUDGE (aim, this_state, this_type);
#endif
                      /* Look forwards. */
                      for (next_state = this_type->rlx_more; next_state;)
                        if (aim <= this_type->rlx_forward)
                          next_state = 0;
                        else
                          {
                            /* Grow to next state. */
                            this_state = next_state;
                            this_type = md_relax_table + this_state;
                            next_state = this_type->rlx_more;
                          }
                    }

                  growth = this_type->rlx_length - start_type->rlx_length;
                  if (growth != 0)
                    fragP->fr_subtype = this_state;
                }
#endif
                break;

              default:
                BAD_CASE (fragP->fr_type);
                break;
              }
            if (growth)
              {
                stretch += growth;
                stretched++;
              }
          }                     /* For each frag in the segment. */
      }
    while (stretched);          /* Until nothing further to relax. */
  }                             /* do_relax */

  /*
   * We now have valid fr_address'es for each frag.
   */

  /*
   * All fr_address's are correct, relative to their own segment.
   * We have made all the fixS we will ever make.
   */
}                               /* relax_segment() */

#if defined (BFD_ASSEMBLER) || !defined (BFD)

/* fixup_segment()

   Go through all the fixS's in a segment and see which ones can be
   handled now.  (These consist of fixS where we have since discovered
   the value of a symbol, or the address of the frag involved.)
   For each one, call md_apply_fix to put the fix into the frag data.

   Result is a count of how many relocation structs will be needed to
   handle the remaining fixS's that we couldn't completely handle here.
   These will be output later by emit_relocations().  */

static long
fixup_segment (fixP, this_segment_type)
     register fixS *fixP;
     segT this_segment_type;    /* N_TYPE bits for segment. */
{
  long seg_reloc_count = 0;
  symbolS *add_symbolP;
  symbolS *sub_symbolP;
  valueT add_number;
  int size;
  char *place;
  long where;
  char pcrel;
  fragS *fragP;
  segT add_symbol_segment = absolute_section;
  
  /* If the linker is doing the relaxing, we must not do any fixups.

     Well, strictly speaking that's not true -- we could do any that are
     PC-relative and don't cross regions that could change size.  And for the
     i960 (the only machine for which we've got a relaxing linker right now),
     we might be able to turn callx/callj into bal anyways in cases where we
     know the maximum displacement.  */
  if (linkrelax)
    {
      for (; fixP; fixP = fixP->fx_next)
        seg_reloc_count++;
      TC_ADJUST_RELOC_COUNT (fixP, seg_reloc_count);
      return seg_reloc_count;
    }

  for (; fixP; fixP = fixP->fx_next)
    {
      fragP = fixP->fx_frag;
      know (fragP);
      where = fixP->fx_where;
      place = fragP->fr_literal + where;
      size = fixP->fx_size;
      add_symbolP = fixP->fx_addsy;
#ifdef TC_VALIDATE_FIX
      TC_VALIDATE_FIX (fixP, this_segment_type, skip);
#endif
      sub_symbolP = fixP->fx_subsy;
      add_number = fixP->fx_offset;
      pcrel = fixP->fx_pcrel;
      
      if (add_symbolP)
        add_symbol_segment = S_GET_SEGMENT (add_symbolP);
      
      if (sub_symbolP)
        {
          if (!add_symbolP)
            {
              /* Its just -sym */
              if (S_GET_SEGMENT (sub_symbolP) == absolute_section)
                add_number -= S_GET_VALUE (sub_symbolP);
              else if (pcrel
                       && S_GET_SEGMENT (sub_symbolP) == this_segment_type)
                {
                  /* Should try converting to a constant.  */
                  goto bad_sub_reloc;
                }
              else
              bad_sub_reloc:
                as_bad_where (fixP->fx_file, fixP->fx_line,
                              "Negative of non-absolute symbol %s",
                              S_GET_NAME (sub_symbolP));
            }
          else if ((S_GET_SEGMENT (sub_symbolP) == add_symbol_segment)
                   && (SEG_NORMAL (add_symbol_segment)
                       || (add_symbol_segment == absolute_section)))
            {
              /* Difference of 2 symbols from same segment.
                 Can't make difference of 2 undefineds: 'value' means
                 something different for N_UNDF. */
#ifdef TC_I960
              /* Makes no sense to use the difference of 2 arbitrary symbols
                 as the target of a call instruction.  */
              if (fixP->fx_tcbit)
                as_bad_where (fixP->fx_file, fixP->fx_line,
                              "callj to difference of 2 symbols");
#endif /* TC_I960 */
              add_number += S_GET_VALUE (add_symbolP) -
                S_GET_VALUE (sub_symbolP);

              add_symbolP = NULL;

              /* Let the target machine make the final determination
                 as to whether or not a relocation will be needed to
                 handle this fixup.  */
              if (!TC_FORCE_RELOCATION (fixP))
                {
                  fixP->fx_addsy = NULL;
                }
            }
          else
            {
              /* Different segments in subtraction. */
              know (!(S_IS_EXTERNAL (sub_symbolP)
                      && (S_GET_SEGMENT (sub_symbolP) == absolute_section)));

              if ((S_GET_SEGMENT (sub_symbolP) == absolute_section))
                add_number -= S_GET_VALUE (sub_symbolP);

#ifdef DIFF_EXPR_OK
              else if (S_GET_SEGMENT (sub_symbolP) == this_segment_type
#if 0 /* Do this even if it's already described as pc-relative.  For example,
         on the m68k, an operand of "pc@(foo-.-2)" should address "foo" in a
         pc-relative mode.  */
                       && pcrel
#endif
                       )
                {
                  /* Make it pc-relative.  */
                  add_number += (md_pcrel_from (fixP)
                                 - S_GET_VALUE (sub_symbolP));
                  pcrel = 1;
                  fixP->fx_pcrel = 1;
                  sub_symbolP = 0;
                  fixP->fx_subsy = 0;
                }
#endif
#ifdef BFD_ASSEMBLER
              else if (fixP->fx_r_type == BFD_RELOC_GPREL32
                       || fixP->fx_r_type == BFD_RELOC_GPREL16)
                {
                  /* Leave it alone.  */
                }
#endif
              else
                {
                  char buf[50];
                  sprint_value (buf, fragP->fr_address + where);
                  as_bad_where (fixP->fx_file, fixP->fx_line,
                                "Can't emit reloc {- %s-seg symbol \"%s\"} @ file address %s.",
                                segment_name (S_GET_SEGMENT (sub_symbolP)),
                                S_GET_NAME (sub_symbolP), buf);
                }
            }
        }

      if (add_symbolP)
        {
          if (add_symbol_segment == this_segment_type && pcrel)
            {
              /*
               * This fixup was made when the symbol's segment was
               * SEG_UNKNOWN, but it is now in the local segment.
               * So we know how to do the address without relocation.
               */
#ifdef TC_I960
              /* reloc_callj() may replace a 'call' with a 'calls' or a
                 'bal', in which cases it modifies *fixP as appropriate.
                 In the case of a 'calls', no further work is required,
                 and *fixP has been set up to make the rest of the code
                 below a no-op. */
              reloc_callj (fixP);
#endif /* TC_I960 */

              add_number += S_GET_VALUE (add_symbolP);
              add_number -= md_pcrel_from (fixP);
              pcrel = 0;        /* Lie. Don't want further pcrel processing. */
              
              /* Let the target machine make the final determination
                 as to whether or not a relocation will be needed to
                 handle this fixup.  */
              if (!TC_FORCE_RELOCATION (fixP))
                {
                  fixP->fx_pcrel = 0;
                  fixP->fx_addsy = NULL;
                }
            }
          else
            {
              if (add_symbol_segment == absolute_section)
                {
#ifdef TC_I960
                  /* See comment about reloc_callj() above.  */
                  reloc_callj (fixP);
#endif /* TC_I960 */
                  add_number += S_GET_VALUE (add_symbolP);

                  /* Let the target machine make the final determination
                     as to whether or not a relocation will be needed to
                     handle this fixup.  */
                  if (!TC_FORCE_RELOCATION (fixP))
                    {
                      fixP->fx_addsy = NULL;
                      add_symbolP = NULL;
                    }
                }
              else if (add_symbol_segment == undefined_section
#ifdef BFD_ASSEMBLER
                       || bfd_is_com_section (add_symbol_segment)
#endif
                       )
                {
#ifdef TC_I960
                  if ((int) fixP->fx_bit_fixP == 13)
                    {
                      /* This is a COBR instruction.  They have only a
                       * 13-bit displacement and are only to be used
                       * for local branches: flag as error, don't generate
                       * relocation.
                       */
                      as_bad_where (fixP->fx_file, fixP->fx_line,
                                    "can't use COBR format with external label");
                      fixP->fx_addsy = NULL;
                      fixP->fx_done = 1;
                      continue;
                    }           /* COBR */
#endif /* TC_I960 */
                  
#ifdef OBJ_COFF
#ifdef TE_I386AIX
                  if (S_IS_COMMON (add_symbolP))
                    add_number += S_GET_VALUE (add_symbolP);
#endif /* TE_I386AIX */
#endif /* OBJ_COFF */
                  ++seg_reloc_count;
                }
              else
                {
                  seg_reloc_count++;
                  add_number += S_GET_VALUE (add_symbolP);
                }
            }
        }

      if (pcrel)
        {
          add_number -= md_pcrel_from (fixP);
          if (add_symbolP == 0)
            {
#ifndef BFD_ASSEMBLER
              fixP->fx_addsy = &abs_symbol;
#else
              fixP->fx_addsy = section_symbol (absolute_section);
#endif
              fixP->fx_addsy->sy_used_in_reloc = 1;
              ++seg_reloc_count;
            }
        }

      if (!fixP->fx_bit_fixP && size > 0)
        {
          valueT mask = 0;
          if (size < sizeof (mask))
            {
              /* set all bits to one */
              mask--;
              /* Technically, combining these produces an undefined result
                 if size is sizeof (valueT), though I think these two
                 half-way operations should both be defined.  And the
                 compiler should be able to combine them if it's valid on
                 the host architecture.  */
              mask <<= size * 4;
              mask <<= size * 4;
              if ((add_number & mask) != 0
                  && (add_number & mask) != mask)
                {
                  char buf[50], buf2[50];
                  sprint_value (buf, fragP->fr_address + where);
                  if (add_number > 1000)
                    sprint_value (buf2, add_number);
                  else
                    sprintf (buf2, "%ld", (long) add_number);
                  as_bad_where (fixP->fx_file, fixP->fx_line,
                                "Value of %s too large for field of %d bytes at %s",
                                buf2, size, buf);
                } /* generic error checking */
            }
#ifdef WARN_SIGNED_OVERFLOW_WORD
          /* Warn if a .word value is too large when treated as a signed
             number.  We already know it is not too negative.  This is to
             catch over-large switches generated by gcc on the 68k.  */
          if (!flag_signed_overflow_ok
              && size == 2
              && add_number > 0x7fff)
            as_bad_where (fixP->fx_file, fixP->fx_line,
                          "Signed .word overflow; switch may be too large; %ld at 0x%lx",
                          (long) add_number,
                          (unsigned long) (fragP->fr_address + where));
#endif
        }                       /* not a bit fix */

      if (!fixP->fx_done)
        {
#ifdef BFD_ASSEMBLER
          md_apply_fix (fixP, &add_number);
#else
          md_apply_fix (fixP, add_number);
#endif

#ifndef TC_HANDLES_FX_DONE
          /* If the tc-* files haven't been converted, assume it's handling
             it the old way, where a null fx_addsy means that the fix has
             been applied completely, and no further work is needed.  */
          if (fixP->fx_addsy == 0 && fixP->fx_pcrel == 0)
            fixP->fx_done = 1;
#endif
        }
#ifdef TC_VALIDATE_FIX
    skip:
#endif
      ;
    }                           /* For each fixS in this segment. */

  TC_ADJUST_RELOC_COUNT (fixP, seg_reloc_count);
  return seg_reloc_count;
}

#endif /* defined (BFD_ASSEMBLER) || !defined (BFD) */

void
number_to_chars_bigendian (buf, val, n)
     char *buf;
     valueT val;
     int n;
{
  if (n > sizeof (val)|| n <= 0)
    abort ();
  while (n--)
    {
      buf[n] = val & 0xff;
      val >>= 8;
    }
}

void
number_to_chars_littleendian (buf, val, n)
     char *buf;
     valueT val;
     int n;
{
  if (n > sizeof (val) || n <= 0)
    abort ();
  while (n--)
    {
      *buf++ = val & 0xff;
      val >>= 8;
    }
}

/* end of write.c */