Avoid undefined behaviour with signed expressions

[deliverable/binutils-gdb.git] / gas / write.c

/* write.c - emit .o file
   Copyright (C) 1986-2014 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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, 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"
#include "dwarf2dbg.h"
#include "libbfd.h"
#include "compress-debug.h"

#ifndef TC_FORCE_RELOCATION
#define TC_FORCE_RELOCATION(FIX)                \
  (generic_force_reloc (FIX))
#endif

#ifndef TC_FORCE_RELOCATION_ABS
#define TC_FORCE_RELOCATION_ABS(FIX)            \
  (TC_FORCE_RELOCATION (FIX))
#endif

#ifndef TC_FORCE_RELOCATION_LOCAL
#define TC_FORCE_RELOCATION_LOCAL(FIX)          \
  (!(FIX)->fx_pcrel                             \
   || TC_FORCE_RELOCATION (FIX))
#endif

#ifndef TC_FORCE_RELOCATION_SUB_SAME
#define TC_FORCE_RELOCATION_SUB_SAME(FIX, SEG)  \
  (! SEG_NORMAL (SEG))
#endif

#ifndef md_register_arithmetic
# define md_register_arithmetic 1
#endif

#ifndef TC_FORCE_RELOCATION_SUB_ABS
#define TC_FORCE_RELOCATION_SUB_ABS(FIX, SEG)   \
  (!md_register_arithmetic && (SEG) == reg_section)
#endif

#ifndef TC_FORCE_RELOCATION_SUB_LOCAL
#ifdef DIFF_EXPR_OK
#define TC_FORCE_RELOCATION_SUB_LOCAL(FIX, SEG) \
  (!md_register_arithmetic && (SEG) == reg_section)
#else
#define TC_FORCE_RELOCATION_SUB_LOCAL(FIX, SEG) 1
#endif
#endif

#ifndef TC_VALIDATE_FIX_SUB
#ifdef UNDEFINED_DIFFERENCE_OK
/* The PA needs this for PIC code generation.  */
#define TC_VALIDATE_FIX_SUB(FIX, SEG)                   \
  (md_register_arithmetic || (SEG) != reg_section)
#else
#define TC_VALIDATE_FIX_SUB(FIX, SEG)                   \
  ((md_register_arithmetic || (SEG) != reg_section)     \
   && ((FIX)->fx_r_type == BFD_RELOC_GPREL32            \
       || (FIX)->fx_r_type == BFD_RELOC_GPREL16))
#endif
#endif

#ifndef TC_LINKRELAX_FIXUP
#define TC_LINKRELAX_FIXUP(SEG) 1
#endif

#ifndef MD_APPLY_SYM_VALUE
#define MD_APPLY_SYM_VALUE(FIX) 1
#endif

#ifndef TC_FINALIZE_SYMS_BEFORE_SIZE_SEG
#define TC_FINALIZE_SYMS_BEFORE_SIZE_SEG 1
#endif

#ifndef MD_PCREL_FROM_SECTION
#define MD_PCREL_FROM_SECTION(FIX, SEC) md_pcrel_from (FIX)
#endif

#ifndef TC_FAKE_LABEL
#define TC_FAKE_LABEL(NAME) (strcmp ((NAME), FAKE_LABEL_NAME) == 0)
#endif

/* Positive values of TC_FX_SIZE_SLACK allow a target to define
   fixups that far past the end of a frag.  Having such fixups
   is of course most most likely a bug in setting fx_size correctly.
   A negative value disables the fixup check entirely, which is
   appropriate for something like the Renesas / SuperH SH_COUNT
   reloc.  */
#ifndef TC_FX_SIZE_SLACK
#define TC_FX_SIZE_SLACK(FIX) 0
#endif

/* Used to control final evaluation of expressions.  */
int finalize_syms = 0;

int symbol_table_frozen;

symbolS *abs_section_sym;

/* Remember the value of dot when parsing expressions.  */
addressT dot_value;

/* The frag that dot_value is based from.  */
fragS *dot_frag;

/* Relocs generated by ".reloc" pseudo.  */
struct reloc_list* reloc_list;

void print_fixup (fixS *);

/* 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;

static int n_fixups;

#define RELOC_ENUM enum bfd_reloc_code_real

/* Create a fixS in obstack 'notes'.  */

static fixS *
fix_new_internal (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.  */
                  RELOC_ENUM r_type     /* Relocation type.  */,
                  int at_beginning)     /* Add to the start of the list?  */
{
  fixS *fixP;

  n_fixups++;

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

  fixP->fx_frag = frag;
  fixP->fx_where = where;
  fixP->fx_size = size;
  /* We've made fx_size a narrow field; check that it's wide enough.  */
  if (fixP->fx_size != size)
    {
      as_bad (_("field fx_size too small to hold %d"), size);
      abort ();
    }
  fixP->fx_addsy = add_symbol;
  fixP->fx_subsy = sub_symbol;
  fixP->fx_offset = offset;
  fixP->fx_dot_value = dot_value;
  fixP->fx_dot_frag = dot_frag;
  fixP->fx_pcrel = pcrel;
  fixP->fx_r_type = r_type;
  fixP->fx_im_disp = 0;
  fixP->fx_pcrel_adjust = 0;
  fixP->fx_bit_fixP = 0;
  fixP->fx_addnumber = 0;
  fixP->fx_tcbit = 0;
  fixP->fx_tcbit2 = 0;
  fixP->fx_done = 0;
  fixP->fx_no_overflow = 0;
  fixP->fx_signed = 0;

#ifdef USING_CGEN
  fixP->fx_cgen.insn = NULL;
  fixP->fx_cgen.opinfo = 0;
#endif

#ifdef TC_FIX_TYPE
  TC_INIT_FIX_DATA (fixP);
#endif

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

  {

    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);

    if (at_beginning)
      {
        fixP->fx_next = *seg_fix_rootP;
        *seg_fix_rootP = fixP;
        if (fixP->fx_next == NULL)
          *seg_fix_tailP = fixP;
      }
    else
      {
        fixP->fx_next = NULL;
        if (*seg_fix_tailP)
          (*seg_fix_tailP)->fx_next = fixP;
        else
          *seg_fix_rootP = fixP;
        *seg_fix_tailP = fixP;
      }
  }

  return fixP;
}

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

fixS *
fix_new (fragS *frag,           /* Which frag?  */
         int where,                     /* Where in that frag?  */
         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.  */
         RELOC_ENUM r_type              /* Relocation type.  */)
{
  return fix_new_internal (frag, where, size, add_symbol,
                           (symbolS *) NULL, offset, pcrel, r_type, FALSE);
}

/* 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 (fragS *frag,               /* Which frag?  */
             int where,                 /* Where in that frag?  */
             int size,                  /* 1, 2, or 4 usually.  */
             expressionS *exp,          /* Expression.  */
             int pcrel,                 /* TRUE if PC-relative relocation.  */
             RELOC_ENUM r_type          /* Relocation type.  */)
{
  symbolS *add = NULL;
  symbolS *sub = NULL;
  offsetT off = 0;

  switch (exp->X_op)
    {
    case O_absent:
      break;

    case O_register:
      as_bad (_("register value used as expression"));
      break;

    case O_add:
      /* This comes up when _GLOBAL_OFFSET_TABLE_+(.-L0) is read, if
         the difference expression cannot immediately be reduced.  */
      {
        symbolS *stmp = make_expr_symbol (exp);

        exp->X_op = O_symbol;
        exp->X_op_symbol = 0;
        exp->X_add_symbol = stmp;
        exp->X_add_number = 0;

        return fix_new_exp (frag, where, size, exp, pcrel, r_type);
      }

    case O_symbol_rva:
      add = exp->X_add_symbol;
      off = exp->X_add_number;
      r_type = BFD_RELOC_RVA;
      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:
      add = make_expr_symbol (exp);
      break;
    }

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

/* Create a fixup at the beginning of FRAG.  The arguments are the same
   as for fix_new, except that WHERE is implicitly 0.  */

fixS *
fix_at_start (fragS *frag, int size, symbolS *add_symbol,
              offsetT offset, int pcrel, RELOC_ENUM r_type)
{
  return fix_new_internal (frag, 0, size, add_symbol,
                           (symbolS *) NULL, offset, pcrel, r_type, TRUE);
}

/* Generic function to determine whether a fixup requires a relocation.  */
int
generic_force_reloc (fixS *fix)
{
  if (fix->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fix->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
    return 1;

  if (fix->fx_addsy == NULL)
    return 0;

  return S_FORCE_RELOC (fix->fx_addsy, fix->fx_subsy == NULL);
}

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

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

/* 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 (/* 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)
{
  if (seg == absolute_section)
    return;

  if ((unsigned int) align > bfd_get_section_alignment (stdoutput, seg))
    bfd_set_section_alignment (stdoutput, seg, align);
}

int
get_recorded_alignment (segT seg)
{
  if (seg == absolute_section)
    return 0;

  return bfd_get_section_alignment (stdoutput, seg);
}

/* Reset the section indices after removing the gas created sections.  */

static void
renumber_sections (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *countparg)
{
  int *countp = (int *) countparg;

  sec->index = *countp;
  ++*countp;
}

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

  for (; frchp; frchp = frchp->frch_next)
    {
      prev_frag->fr_next = frchp->frch_root;
      prev_frag = frchp->frch_last;
      gas_assert (prev_frag->fr_type != 0);
      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;
        }
    }
  gas_assert (prev_frag != &dummy
              && prev_frag->fr_type != 0);
  prev_frag->fr_next = 0;
  return prev_frag;
}

static void
chain_frchains_together (bfd *abfd ATTRIBUTE_UNUSED,
                         segT section,
                         void *xxx ATTRIBUTE_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;
}

static void
cvt_frag_to_fill (segT sec ATTRIBUTE_UNUSED, fragS *fragP)
{
  switch (fragP->fr_type)
    {
    case rs_align:
    case rs_align_code:
    case rs_align_test:
    case rs_org:
    case rs_space:
#ifdef HANDLE_ALIGN
      HANDLE_ALIGN (fragP);
#endif
      know (fragP->fr_next != NULL);
      fragP->fr_offset = (fragP->fr_next->fr_address
                          - fragP->fr_address
                          - fragP->fr_fix) / fragP->fr_var;
      if (fragP->fr_offset < 0)
        {
          as_bad_where (fragP->fr_file, fragP->fr_line,
                        _("attempt to .org/.space backwards? (%ld)"),
                        (long) fragP->fr_offset);
          fragP->fr_offset = 0;
        }
      fragP->fr_type = rs_fill;
      break;

    case rs_fill:
      break;

    case rs_leb128:
      {
        valueT value = S_GET_VALUE (fragP->fr_symbol);
        int size;

        size = output_leb128 (fragP->fr_literal + fragP->fr_fix, value,
                              fragP->fr_subtype);

        fragP->fr_fix += size;
        fragP->fr_type = rs_fill;
        fragP->fr_var = 0;
        fragP->fr_offset = 0;
        fragP->fr_symbol = NULL;
      }
      break;

    case rs_cfa:
      eh_frame_convert_frag (fragP);
      break;

    case rs_dwarf2dbg:
      dwarf2dbg_convert_frag (fragP);
      break;

    case rs_machine_dependent:
      md_convert_frag (stdoutput, sec, fragP);

      gas_assert (fragP->fr_next == NULL
              || ((offsetT) (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;
    }
#ifdef md_frag_check
  md_frag_check (fragP);
#endif
}

struct relax_seg_info
{
  int pass;
  int changed;
};

static void
relax_seg (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *xxx)
{
  segment_info_type *seginfo = seg_info (sec);
  struct relax_seg_info *info = (struct relax_seg_info *) xxx;

  if (seginfo && seginfo->frchainP
      && relax_segment (seginfo->frchainP->frch_root, sec, info->pass))
    info->changed = 1;
}

static void
size_seg (bfd *abfd, asection *sec, void *xxx ATTRIBUTE_UNUSED)
{
  flagword flags;
  fragS *fragp;
  segment_info_type *seginfo;
  int x;
  valueT size, newsize;

  subseg_change (sec, 0);

  seginfo = seg_info (sec);
  if (seginfo && seginfo->frchainP)
    {
      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;

  flags = bfd_get_section_flags (abfd, sec);
  if (size == 0 && bfd_get_section_size (sec) != 0 &&
    (flags & SEC_HAS_CONTENTS) != 0)
    return;

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

  flags &= ~SEC_RELOC;
  x = bfd_set_section_flags (abfd, sec, flags);
  gas_assert (x);

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

  /* If the size had to be rounded up, add some padding in the last
     non-empty frag.  */
  gas_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;
      if ((newsize - size) % fragp->fr_var == 0)
        fragp->fr_offset += (newsize - size) / fragp->fr_var;
      else
        /* If we hit this abort, it's likely due to subsegs_finish not
           providing sufficient alignment on the last frag, and the
           machine dependent code using alignment frags with fr_var
           greater than 1.  */
        abort ();
    }

#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 (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, 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;

      fprintf (stream, "  %08lx: type %d ", (unsigned long) fixp,
               (int) fixp->fx_r_type);
      if (s == NULL)
        fprintf (stream, "no sym\n");
      else
        {
          print_symbol_value_1 (stream, s);
          fprintf (stream, "\n");
        }
      fixp = fixp->fx_next;
    }
}
#else
#define dump_section_relocs(ABFD,SEC,STREAM)    ((void) 0)
#endif

#ifndef EMIT_SECTION_SYMBOLS
#define EMIT_SECTION_SYMBOLS 1
#endif

/* Resolve U.A.OFFSET_SYM and U.A.SYM fields of RELOC_LIST entries,
   and check for validity.  Convert RELOC_LIST from using U.A fields
   to U.B fields.  */
static void
resolve_reloc_expr_symbols (void)
{
  bfd_vma addr_mask = 1;
  struct reloc_list *r;

  /* Avoid a shift by the width of type.  */
  addr_mask <<= bfd_arch_bits_per_address (stdoutput) - 1;
  addr_mask <<= 1;
  addr_mask -= 1;

  for (r = reloc_list; r; r = r->next)
    {
      reloc_howto_type *howto = r->u.a.howto;
      expressionS *symval;
      symbolS *sym;
      bfd_vma offset, addend;
      asection *sec;

      resolve_symbol_value (r->u.a.offset_sym);
      symval = symbol_get_value_expression (r->u.a.offset_sym);

      offset = 0;
      sym = NULL;
      if (symval->X_op == O_constant)
        sym = r->u.a.offset_sym;
      else if (symval->X_op == O_symbol)
        {
          sym = symval->X_add_symbol;
          offset = symval->X_add_number;
          symval = symbol_get_value_expression (symval->X_add_symbol);
        }
      if (sym == NULL
          || symval->X_op != O_constant
          || (sec = S_GET_SEGMENT (sym)) == NULL
          || !SEG_NORMAL (sec))
        {
          as_bad_where (r->file, r->line, _("invalid offset expression"));
          sec = NULL;
        }
      else
        offset += S_GET_VALUE (sym);

      sym = NULL;
      addend = r->u.a.addend;
      if (r->u.a.sym != NULL)
        {
          resolve_symbol_value (r->u.a.sym);
          symval = symbol_get_value_expression (r->u.a.sym);
          if (symval->X_op == O_constant)
            sym = r->u.a.sym;
          else if (symval->X_op == O_symbol)
            {
              sym = symval->X_add_symbol;
              addend += symval->X_add_number;
              symval = symbol_get_value_expression (symval->X_add_symbol);
            }
          if (symval->X_op != O_constant)
            {
              as_bad_where (r->file, r->line, _("invalid reloc expression"));
              sec = NULL;
            }
          else if (sym != NULL)
            {
              /* Convert relocs against local symbols to refer to the
                 corresponding section symbol plus offset instead.  Keep
                 PC-relative relocs of the REL variety intact though to
                 prevent the offset from overflowing the relocated field,
                 unless it has enough bits to cover the whole address
                 space.  */
              if (S_IS_LOCAL (sym) && !symbol_section_p (sym)
                  && (sec->use_rela_p
                      || (howto->partial_inplace
                          && (!howto->pc_relative
                              || howto->src_mask == addr_mask))))
                {
                  asection *symsec = S_GET_SEGMENT (sym);
                  if (!(((symsec->flags & SEC_MERGE) != 0
                         && addend != 0)
                        || (symsec->flags & SEC_THREAD_LOCAL) != 0))
                    {
                      addend += S_GET_VALUE (sym);
                      sym = section_symbol (symsec);
                    }
                }
              symbol_mark_used_in_reloc (sym);
            }
        }
      if (sym == NULL)
        {
          if (abs_section_sym == NULL)
            abs_section_sym = section_symbol (absolute_section);
          sym = abs_section_sym;
        }

      r->u.b.sec = sec;
      r->u.b.s = symbol_get_bfdsym (sym);
      r->u.b.r.sym_ptr_ptr = &r->u.b.s;
      r->u.b.r.address = offset;
      r->u.b.r.addend = addend;
      r->u.b.r.howto = howto;
    }
}

/* This pass over fixups decides whether symbols can be replaced with
   section symbols.  */

static void
adjust_reloc_syms (bfd *abfd ATTRIBUTE_UNUSED,
                   asection *sec,
                   void *xxx ATTRIBUTE_UNUSED)
{
  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;
        asection *symsec;

#ifdef DEBUG5
        fprintf (stderr, "\n\nadjusting fixup:\n");
        print_fixup (fixp);
#endif

        sym = fixp->fx_addsy;

        /* All symbols should have already been resolved at this
           point.  It is possible to see unresolved expression
           symbols, though, since they are not in the regular symbol
           table.  */
        resolve_symbol_value (sym);

        if (fixp->fx_subsy != NULL)
          resolve_symbol_value (fixp->fx_subsy);

        /* If this symbol is equated to an undefined or common symbol,
           convert the fixup to being against that symbol.  */
        while (symbol_equated_reloc_p (sym)
               || S_IS_WEAKREFR (sym))
          {
            symbolS *newsym = symbol_get_value_expression (sym)->X_add_symbol;
            if (sym == newsym)
              break;
            fixp->fx_offset += symbol_get_value_expression (sym)->X_add_number;
            fixp->fx_addsy = newsym;
            sym = newsym;
          }

        if (symbol_mri_common_p (sym))
          {
            fixp->fx_offset += S_GET_VALUE (sym);
            fixp->fx_addsy = symbol_get_value_expression (sym)->X_add_symbol;
            continue;
          }

        /* If the symbol is undefined, common, weak, or global (ELF
           shared libs), we can't replace it with the section symbol.  */
        if (S_FORCE_RELOC (fixp->fx_addsy, 1))
          continue;

        /* 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))
          continue;
#endif

        /* Since we're reducing to section symbols, don't attempt to reduce
           anything that's already using one.  */
        if (symbol_section_p (sym))
          continue;

        symsec = S_GET_SEGMENT (sym);
        if (symsec == NULL)
          abort ();

        if (bfd_is_abs_section (symsec))
          {
            /* The fixup_segment routine normally will not use this
               symbol in a relocation.  */
            continue;
          }

        /* Don't try to reduce relocs which refer to non-local symbols
           in .linkonce sections.  It can lead to confusion when a
           debugging section refers to a .linkonce section.  I hope
           this will always be correct.  */
        if (symsec != sec && ! S_IS_LOCAL (sym))
          {
            if ((symsec->flags & SEC_LINK_ONCE) != 0
                || (IS_ELF
                    /* The GNU toolchain uses an extension for ELF: a
                       section beginning with the magic string
                       .gnu.linkonce is a linkonce section.  */
                    && strncmp (segment_name (symsec), ".gnu.linkonce",
                                sizeof ".gnu.linkonce" - 1) == 0))
              continue;
          }

        /* Never adjust a reloc against local symbol in a merge section
           with non-zero addend.  */
        if ((symsec->flags & SEC_MERGE) != 0
            && (fixp->fx_offset != 0 || fixp->fx_subsy != NULL))
          continue;

        /* Never adjust a reloc against TLS local symbol.  */
        if ((symsec->flags & SEC_THREAD_LOCAL) != 0)
          continue;

        /* We refetch the segment when calling section_symbol, rather
           than using symsec, because S_GET_VALUE may wind up changing
           the section when it calls resolve_symbol_value.  */
        fixp->fx_offset += S_GET_VALUE (sym);
        fixp->fx_addsy = section_symbol (S_GET_SEGMENT (sym));
#ifdef DEBUG5
        fprintf (stderr, "\nadjusted fixup:\n");
        print_fixup (fixp);
#endif
      }

  dump_section_relocs (abfd, sec, stderr);
}

/* 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.
   Ones that we couldn't completely handle here will be output later
   by emit_relocations.  */

static void
fixup_segment (fixS *fixP, segT this_segment)
{
  valueT add_number;
  fragS *fragP;
  segT add_symbol_segment = absolute_section;

  if (fixP != NULL && abs_section_sym == NULL)
    abs_section_sym = section_symbol (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 we might be able to turn callx/callj into bal
     anyways in cases where we know the maximum displacement.  */
  if (linkrelax && TC_LINKRELAX_FIXUP (this_segment))
    {
      for (; fixP; fixP = fixP->fx_next)
        if (!fixP->fx_done)
          {
            if (fixP->fx_addsy == NULL)
              {
                /* There was no symbol required by this relocation.
                   However, BFD doesn't really handle relocations
                   without symbols well. So fake up a local symbol in
                   the absolute section.  */
                fixP->fx_addsy = abs_section_sym;
              }
            symbol_mark_used_in_reloc (fixP->fx_addsy);
            if (fixP->fx_subsy != NULL)
              symbol_mark_used_in_reloc (fixP->fx_subsy);
          }
      return;
    }

  for (; fixP; fixP = fixP->fx_next)
    {
#ifdef DEBUG5
      fprintf (stderr, "\nprocessing fixup:\n");
      print_fixup (fixP);
#endif

      fragP = fixP->fx_frag;
      know (fragP);
#ifdef TC_VALIDATE_FIX
      TC_VALIDATE_FIX (fixP, this_segment, skip);
#endif
      add_number = fixP->fx_offset;

      if (fixP->fx_addsy != NULL)
        add_symbol_segment = S_GET_SEGMENT (fixP->fx_addsy);

      if (fixP->fx_subsy != NULL)
        {
          segT sub_symbol_segment;
          resolve_symbol_value (fixP->fx_subsy);
          sub_symbol_segment = S_GET_SEGMENT (fixP->fx_subsy);
          if (fixP->fx_addsy != NULL
              && sub_symbol_segment == add_symbol_segment
              && !S_FORCE_RELOC (fixP->fx_addsy, 0)
              && !S_FORCE_RELOC (fixP->fx_subsy, 0)
              && !TC_FORCE_RELOCATION_SUB_SAME (fixP, add_symbol_segment))
            {
              add_number += S_GET_VALUE (fixP->fx_addsy);
              add_number -= S_GET_VALUE (fixP->fx_subsy);
              fixP->fx_offset = add_number;
              fixP->fx_addsy = NULL;
              fixP->fx_subsy = NULL;
#ifdef TC_M68K
              /* See the comment below about 68k weirdness.  */
              fixP->fx_pcrel = 0;
#endif
            }
          else if (sub_symbol_segment == absolute_section
                   && !S_FORCE_RELOC (fixP->fx_subsy, 0)
                   && !TC_FORCE_RELOCATION_SUB_ABS (fixP, add_symbol_segment))
            {
              add_number -= S_GET_VALUE (fixP->fx_subsy);
              fixP->fx_offset = add_number;
              fixP->fx_subsy = NULL;
            }
          else if (sub_symbol_segment == this_segment
                   && !S_FORCE_RELOC (fixP->fx_subsy, 0)
                   && !TC_FORCE_RELOCATION_SUB_LOCAL (fixP, add_symbol_segment))
            {
              add_number -= S_GET_VALUE (fixP->fx_subsy);
              fixP->fx_offset = (add_number + fixP->fx_dot_value
                                 + fixP->fx_dot_frag->fr_address);

              /* Make it pc-relative.  If the back-end code has not
                 selected a pc-relative reloc, cancel the adjustment
                 we do later on all pc-relative relocs.  */
              if (0
#ifdef TC_M68K
                  /* Do this for m68k even if it's already described
                     as pc-relative.  On the m68k, an operand of
                     "pc@(foo-.-2)" should address "foo" in a
                     pc-relative mode.  */
                  || 1
#endif
                  || !fixP->fx_pcrel)
                add_number += MD_PCREL_FROM_SECTION (fixP, this_segment);
              fixP->fx_subsy = NULL;
              fixP->fx_pcrel = 1;
            }
          else if (!TC_VALIDATE_FIX_SUB (fixP, add_symbol_segment))
            {
              if (!md_register_arithmetic
                  && (add_symbol_segment == reg_section
                      || sub_symbol_segment == reg_section))
                as_bad_where (fixP->fx_file, fixP->fx_line,
                              _("register value used as expression"));
              else
                as_bad_where (fixP->fx_file, fixP->fx_line,
                              _("can't resolve `%s' {%s section} - `%s' {%s section}"),
                              fixP->fx_addsy ? S_GET_NAME (fixP->fx_addsy) : "0",
                              segment_name (add_symbol_segment),
                              S_GET_NAME (fixP->fx_subsy),
                              segment_name (sub_symbol_segment));
            }
          else if (sub_symbol_segment != undefined_section
                   && ! bfd_is_com_section (sub_symbol_segment)
                   && MD_APPLY_SYM_VALUE (fixP))
            add_number -= S_GET_VALUE (fixP->fx_subsy);
        }

      if (fixP->fx_addsy)
        {
          if (add_symbol_segment == this_segment
              && !S_FORCE_RELOC (fixP->fx_addsy, 0)
              && !TC_FORCE_RELOCATION_LOCAL (fixP))
            {
              /* 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.  */
              add_number += S_GET_VALUE (fixP->fx_addsy);
              fixP->fx_offset = add_number;
              if (fixP->fx_pcrel)
                add_number -= MD_PCREL_FROM_SECTION (fixP, this_segment);
              fixP->fx_addsy = NULL;
              fixP->fx_pcrel = 0;
            }
          else if (add_symbol_segment == absolute_section
                   && !S_FORCE_RELOC (fixP->fx_addsy, 0)
                   && !TC_FORCE_RELOCATION_ABS (fixP))
            {
              add_number += S_GET_VALUE (fixP->fx_addsy);
              fixP->fx_offset = add_number;
              fixP->fx_addsy = NULL;
            }
          else if (add_symbol_segment != undefined_section
                   && ! bfd_is_com_section (add_symbol_segment)
                   && MD_APPLY_SYM_VALUE (fixP))
            add_number += S_GET_VALUE (fixP->fx_addsy);
        }

      if (fixP->fx_pcrel)
        {
          add_number -= MD_PCREL_FROM_SECTION (fixP, this_segment);
          if (!fixP->fx_done && fixP->fx_addsy == NULL)
            {
              /* There was no symbol required by this relocation.
                 However, BFD doesn't really handle relocations
                 without symbols well. So fake up a local symbol in
                 the absolute section.  */
              fixP->fx_addsy = abs_section_sym;
            }
        }

      if (!fixP->fx_done)
        md_apply_fix (fixP, &add_number, this_segment);

      if (!fixP->fx_done)
        {
          if (fixP->fx_addsy == NULL)
            fixP->fx_addsy = abs_section_sym;
          symbol_mark_used_in_reloc (fixP->fx_addsy);
          if (fixP->fx_subsy != NULL)
            symbol_mark_used_in_reloc (fixP->fx_subsy);
        }

      if (!fixP->fx_bit_fixP && !fixP->fx_no_overflow && fixP->fx_size != 0)
        {
          if (fixP->fx_size < sizeof (valueT))
            {
              valueT mask;

              mask = 0;
              mask--;           /* Set all bits to one.  */
              mask <<= fixP->fx_size * 8 - (fixP->fx_signed ? 1 : 0);
              if ((add_number & mask) != 0 && (add_number & mask) != mask)
                {
                  char buf[50], buf2[50];
                  sprint_value (buf, fragP->fr_address + fixP->fx_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, fixP->fx_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
              && fixP->fx_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,
                          (long) (fragP->fr_address + fixP->fx_where));
#endif
        }                       /* Not a bit fix.  */

#ifdef TC_VALIDATE_FIX
    skip:  ATTRIBUTE_UNUSED_LABEL
      ;
#endif
#ifdef DEBUG5
      fprintf (stderr, "result:\n");
      print_fixup (fixP);
#endif
    }                           /* For each fixS in this segment.  */
}

static void
fix_segment (bfd *abfd ATTRIBUTE_UNUSED,
             asection *sec,
             void *xxx ATTRIBUTE_UNUSED)
{
  segment_info_type *seginfo = seg_info (sec);

  fixup_segment (seginfo->fix_root, sec);
}

static void
install_reloc (asection *sec, arelent *reloc, fragS *fragp,
               char *file, unsigned int line)
{
  char *err;
  bfd_reloc_status_type s;
  asymbol *sym;

  if (reloc->sym_ptr_ptr != NULL
      && (sym = *reloc->sym_ptr_ptr) != NULL
      && (sym->flags & BSF_KEEP) == 0
      && ((sym->flags & BSF_SECTION_SYM) == 0
          || (EMIT_SECTION_SYMBOLS
              && !bfd_is_abs_section (sym->section))))
    as_bad_where (file, line, _("redefined symbol cannot be used on reloc"));

  s = bfd_install_relocation (stdoutput, reloc,
                              fragp->fr_literal, fragp->fr_address,
                              sec, &err);
  switch (s)
    {
    case bfd_reloc_ok:
      break;
    case bfd_reloc_overflow:
      as_bad_where (file, line, _("relocation overflow"));
      break;
    case bfd_reloc_outofrange:
      as_bad_where (file, line, _("relocation out of range"));
      break;
    default:
      as_fatal (_("%s:%u: bad return from bfd_install_relocation: %x"),
                file, line, s);
    }
}

static fragS *
get_frag_for_reloc (fragS *last_frag,
                    const segment_info_type *seginfo,
                    const struct reloc_list *r)
{
  fragS *f;

  for (f = last_frag; f != NULL; f = f->fr_next)
    if (f->fr_address <= r->u.b.r.address
        && r->u.b.r.address < f->fr_address + f->fr_fix)
      return f;

  for (f = seginfo->frchainP->frch_root; f != NULL; f = f->fr_next)
    if (f->fr_address <= r->u.b.r.address
        && r->u.b.r.address < f->fr_address + f->fr_fix)
      return f;

  as_bad_where (r->file, r->line,
                _("reloc not within (fixed part of) section"));
  return NULL;
}

static void
write_relocs (bfd *abfd, asection *sec, void *xxx ATTRIBUTE_UNUSED)
{
  segment_info_type *seginfo = seg_info (sec);
  unsigned int n;
  struct reloc_list *my_reloc_list, **rp, *r;
  arelent **relocs;
  fixS *fixp;
  fragS *last_frag;

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

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

#ifdef RELOC_EXPANSION_POSSIBLE
  n *= MAX_RELOC_EXPANSION;
#endif

  /* Extract relocs for this section from reloc_list.  */
  rp = &reloc_list;
  my_reloc_list = NULL;
  while ((r = *rp) != NULL)
    {
      if (r->u.b.sec == sec)
        {
          *rp = r->next;
          r->next = my_reloc_list;
          my_reloc_list = r;
          n++;
        }
      else
        rp = &r->next;
    }

  relocs = (arelent **) xcalloc (n, sizeof (arelent *));

  n = 0;
  r = my_reloc_list;
  last_frag = NULL;
  for (fixp = seginfo->fix_root; fixp != (fixS *) NULL; fixp = fixp->fx_next)
    {
      int fx_size, slack;
      offsetT loc;
      arelent **reloc;
#ifndef RELOC_EXPANSION_POSSIBLE
      arelent *rel;

      reloc = &rel;
#endif

      if (fixp->fx_done)
        continue;

      fx_size = fixp->fx_size;
      slack = TC_FX_SIZE_SLACK (fixp);
      if (slack > 0)
        fx_size = fx_size > slack ? fx_size - slack : 0;
      loc = fixp->fx_where + fx_size;
      if (slack >= 0 && loc > fixp->fx_frag->fr_fix)
        as_bad_where (fixp->fx_file, fixp->fx_line,
                      _("internal error: fixup not contained within frag"));

#ifndef RELOC_EXPANSION_POSSIBLE
      *reloc = tc_gen_reloc (sec, fixp);
#else
      reloc = tc_gen_reloc (sec, fixp);
#endif

      while (*reloc)
        {
          while (r != NULL && r->u.b.r.address < (*reloc)->address)
            {
              fragS *f = get_frag_for_reloc (last_frag, seginfo, r);
              if (f != NULL)
                {
                  last_frag = f;
                  relocs[n++] = &r->u.b.r;
                  install_reloc (sec, &r->u.b.r, f, r->file, r->line);
                }
              r = r->next;
            }
          relocs[n++] = *reloc;
          install_reloc (sec, *reloc, fixp->fx_frag,
                         fixp->fx_file, fixp->fx_line);
#ifndef RELOC_EXPANSION_POSSIBLE
          break;
#else
          reloc++;
#endif
        }
    }

  while (r != NULL)
    {
      fragS *f = get_frag_for_reloc (last_frag, seginfo, r);
      if (f != NULL)
        {
          last_frag = f;
          relocs[n++] = &r->u.b.r;
          install_reloc (sec, &r->u.b.r, f, r->file, r->line);
        }
      r = r->next;
    }

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

  if (n)
    {
      flagword flags = bfd_get_section_flags (abfd, sec);
      flags |= SEC_RELOC;
      bfd_set_section_flags (abfd, sec, flags);
      bfd_set_reloc (stdoutput, sec, relocs, n);
    }

#ifdef SET_SECTION_RELOCS
  SET_SECTION_RELOCS (sec, relocs, n);
#endif

#ifdef DEBUG3
  {
    unsigned int k;

    fprintf (stderr, "relocs for sec %s\n", sec->name);
    for (k = 0; k < n; k++)
      {
        arelent *rel = relocs[k];
        asymbol *s = *rel->sym_ptr_ptr;
        fprintf (stderr, "  reloc %2d @%p off %4lx : sym %-10s addend %lx\n",
                 k, rel, (unsigned long)rel->address, s->name,
                 (unsigned long)rel->addend);
      }
  }
#endif
}

static int
compress_frag (struct z_stream_s *strm, const char *contents, int in_size,
               fragS **last_newf, struct obstack *ob)
{
  int out_size;
  int total_out_size = 0;
  fragS *f = *last_newf;
  char *next_out;
  int avail_out;

  /* Call the compression routine repeatedly until it has finished
     processing the frag.  */
  while (in_size > 0)
    {
      /* Reserve all the space available in the current chunk.
         If none is available, start a new frag.  */
      avail_out = obstack_room (ob);
      if (avail_out <= 0)
        {
          obstack_finish (ob);
          f = frag_alloc (ob);
          f->fr_type = rs_fill;
          (*last_newf)->fr_next = f;
          *last_newf = f;
          avail_out = obstack_room (ob);
        }
      if (avail_out <= 0)
        as_fatal (_("can't extend frag"));
      next_out = obstack_next_free (ob);
      obstack_blank_fast (ob, avail_out);
      out_size = compress_data (strm, &contents, &in_size,
                                &next_out, &avail_out);
      if (out_size < 0)
        return -1;

      f->fr_fix += out_size;
      total_out_size += out_size;

      /* Return unused space.  */
      if (avail_out > 0)
        obstack_blank_fast (ob, -avail_out);
    }

  return total_out_size;
}

static void
compress_debug (bfd *abfd, asection *sec, void *xxx ATTRIBUTE_UNUSED)
{
  segment_info_type *seginfo = seg_info (sec);
  fragS *f;
  fragS *first_newf;
  fragS *last_newf;
  struct obstack *ob = &seginfo->frchainP->frch_obstack;
  bfd_size_type uncompressed_size = (bfd_size_type) sec->size;
  bfd_size_type compressed_size;
  const char *section_name;
  char *compressed_name;
  char *header;
  struct z_stream_s *strm;
  int x;
  flagword flags = bfd_get_section_flags (abfd, sec);

  if (seginfo == NULL
      || sec->size < 32
      || (flags & (SEC_ALLOC | SEC_HAS_CONTENTS)) == SEC_ALLOC)
    return;

  section_name = bfd_get_section_name (stdoutput, sec);
  if (strncmp (section_name, ".debug_", 7) != 0)
    return;

  strm = compress_init ();
  if (strm == NULL)
    return;

  /* Create a new frag to contain the "ZLIB" header.  */
  first_newf = frag_alloc (ob);
  if (obstack_room (ob) < 12)
    first_newf = frag_alloc (ob);
  if (obstack_room (ob) < 12)
    as_fatal (_("can't extend frag %u chars"), 12);
  last_newf = first_newf;
  obstack_blank_fast (ob, 12);
  last_newf->fr_type = rs_fill;
  last_newf->fr_fix = 12;
  header = last_newf->fr_literal;
  memcpy (header, "ZLIB", 4);
  header[11] = uncompressed_size; uncompressed_size >>= 8;
  header[10] = uncompressed_size; uncompressed_size >>= 8;
  header[9] = uncompressed_size; uncompressed_size >>= 8;
  header[8] = uncompressed_size; uncompressed_size >>= 8;
  header[7] = uncompressed_size; uncompressed_size >>= 8;
  header[6] = uncompressed_size; uncompressed_size >>= 8;
  header[5] = uncompressed_size; uncompressed_size >>= 8;
  header[4] = uncompressed_size;
  compressed_size = 12;

  /* Stream the frags through the compression engine, adding new frags
     as necessary to accomodate the compressed output.  */
  for (f = seginfo->frchainP->frch_root;
       f;
       f = f->fr_next)
    {
      offsetT fill_size;
      char *fill_literal;
      offsetT count;
      int out_size;

      gas_assert (f->fr_type == rs_fill);
      if (f->fr_fix)
        {
          out_size = compress_frag (strm, f->fr_literal, f->fr_fix,
                                    &last_newf, ob);
          if (out_size < 0)
            return;
          compressed_size += out_size;
        }
      fill_literal = f->fr_literal + f->fr_fix;
      fill_size = f->fr_var;
      count = f->fr_offset;
      gas_assert (count >= 0);
      if (fill_size && count)
        {
          while (count--)
            {
              out_size = compress_frag (strm, fill_literal, (int) fill_size,
                                        &last_newf, ob);
              if (out_size < 0)
                return;
              compressed_size += out_size;
            }
        }
    }

  /* Flush the compression state.  */
  for (;;)
    {
      int avail_out;
      char *next_out;
      int out_size;

      /* Reserve all the space available in the current chunk.
         If none is available, start a new frag.  */
      avail_out = obstack_room (ob);
      if (avail_out <= 0)
        {
          fragS *newf;

          obstack_finish (ob);
          newf = frag_alloc (ob);
          newf->fr_type = rs_fill;
          last_newf->fr_next = newf;
          last_newf = newf;
          avail_out = obstack_room (ob);
        }
      if (avail_out <= 0)
        as_fatal (_("can't extend frag"));
      next_out = obstack_next_free (ob);
      obstack_blank_fast (ob, avail_out);
      x = compress_finish (strm, &next_out, &avail_out, &out_size);
      if (x < 0)
        return;

      last_newf->fr_fix += out_size;
      compressed_size += out_size;

      /* Return unused space.  */
      if (avail_out > 0)
        obstack_blank_fast (ob, -avail_out);

      if (x == 0)
        break;
    }

  /* Replace the uncompressed frag list with the compressed frag list.  */
  seginfo->frchainP->frch_root = first_newf;
  seginfo->frchainP->frch_last = last_newf;

  /* Update the section size and its name.  */
  x = bfd_set_section_size (abfd, sec, compressed_size);
  gas_assert (x);
  compressed_name = (char *) xmalloc (strlen (section_name) + 2);
  compressed_name[0] = '.';
  compressed_name[1] = 'z';
  strcpy (compressed_name + 2, section_name + 1);
  bfd_section_name (stdoutput, sec) = compressed_name;
}

static void
write_contents (bfd *abfd ATTRIBUTE_UNUSED,
                asection *sec,
                void *xxx ATTRIBUTE_UNUSED)
{
  segment_info_type *seginfo = seg_info (sec);
  addressT 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;
      addressT fill_size;
      char *fill_literal;
      offsetT count;

      gas_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)
            as_fatal (_("can't write %s: %s"), stdoutput->filename,
                      bfd_errmsg (bfd_get_error ()));
          offset += f->fr_fix;
        }
      fill_literal = f->fr_literal + f->fr_fix;
      fill_size = f->fr_var;
      count = f->fr_offset;
      gas_assert (count >= 0);
      if (fill_size && count)
        {
          char buf[256];
          if (fill_size > sizeof (buf))
            {
              /* Do it the old way. Can this ever happen?  */
              while (count--)
                {
                  x = bfd_set_section_contents (stdoutput, sec,
                                                fill_literal,
                                                (file_ptr) offset,
                                                (bfd_size_type) fill_size);
                  if (!x)
                    as_fatal (_("can't write %s: %s"), stdoutput->filename,
                              bfd_errmsg (bfd_get_error ()));
                  offset += fill_size;
                }
            }
          else
            {
              /* Build a buffer full of fill objects and output it as
                 often as necessary. This saves on the overhead of
                 potentially lots of bfd_set_section_contents calls.  */
              int n_per_buf, i;
              if (fill_size == 1)
                {
                  n_per_buf = sizeof (buf);
                  memset (buf, *fill_literal, n_per_buf);
                }
              else
                {
                  char *bufp;
                  n_per_buf = sizeof (buf) / fill_size;
                  for (i = n_per_buf, bufp = buf; i; i--, bufp += fill_size)
                    memcpy (bufp, fill_literal, fill_size);
                }
              for (; count > 0; count -= n_per_buf)
                {
                  n_per_buf = n_per_buf > count ? count : n_per_buf;
                  x = bfd_set_section_contents
                    (stdoutput, sec, buf, (file_ptr) offset,
                     (bfd_size_type) n_per_buf * fill_size);
                  if (!x)
                    as_fatal (_("cannot write to output file '%s': %s"),
                              stdoutput->filename,
                              bfd_errmsg (bfd_get_error ()));
                  offset += n_per_buf * fill_size;
                }
            }
        }
    }
}

static void
merge_data_into_text (void)
{
  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;
}

static void
set_symtab (void)
{
  int nsyms;
  asymbol **asympp;
  symbolS *symp;
  bfd_boolean result;

  /* 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;
      bfd_size_type amt = (bfd_size_type) nsyms * sizeof (asymbol *);

      asympp = (asymbol **) bfd_alloc (stdoutput, amt);
      symp = symbol_rootP;
      for (i = 0; i < nsyms; i++, symp = symbol_next (symp))
        {
          asympp[i] = symbol_get_bfdsym (symp);
          if (asympp[i]->flags != BSF_SECTION_SYM
              || !(bfd_is_const_section (asympp[i]->section)
                   && asympp[i]->section->symbol == asympp[i]))
            asympp[i]->flags |= BSF_KEEP;
          symbol_mark_written (symp);
        }
    }
  else
    asympp = 0;
  result = bfd_set_symtab (stdoutput, asympp, nsyms);
  gas_assert (result);
  symbol_table_frozen = 1;
}

/* Finish the subsegments.  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.  */

#ifndef SUB_SEGMENT_ALIGN
#ifdef HANDLE_ALIGN
/* The last subsegment gets an alignment corresponding to the alignment
   of the section.  This allows proper nop-filling at the end of
   code-bearing sections.  */
#define SUB_SEGMENT_ALIGN(SEG, FRCHAIN)                                 \
  (!(FRCHAIN)->frch_next ? get_recorded_alignment (SEG) : 0)
#else
#define SUB_SEGMENT_ALIGN(SEG, FRCHAIN) 0
#endif
#endif

static void
subsegs_finish_section (asection *s)
{
  struct frchain *frchainP;
  segment_info_type *seginfo = seg_info (s);
  if (!seginfo)
    return;

  for (frchainP = seginfo->frchainP;
       frchainP != NULL;
       frchainP = frchainP->frch_next)
    {
      int alignment = 0;

      subseg_set (s, frchainP->frch_subseg);

      /* This now gets called even if we had errors.  In that case,
         any alignment is meaningless, and, moreover, will look weird
         if we are generating a listing.  */
      if (!had_errors ())
        {
          alignment = SUB_SEGMENT_ALIGN (now_seg, frchainP);
          if ((bfd_get_section_flags (now_seg->owner, now_seg) & SEC_MERGE)
              && now_seg->entsize)
            {
              unsigned int entsize = now_seg->entsize;
              int entalign = 0;

              while ((entsize & 1) == 0)
                {
                  ++entalign;
                  entsize >>= 1;
                }

              if (entalign > alignment)
                alignment = entalign;
            }
        }

      if (subseg_text_p (now_seg))
        frag_align_code (alignment, 0);
      else
        frag_align (alignment, 0, 0);

      /* 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);
    }
}

static void
subsegs_finish (void)
{
  asection *s;

  for (s = stdoutput->sections; s; s = s->next)
    subsegs_finish_section (s);
}

#ifdef OBJ_ELF
static void
create_obj_attrs_section (void)
{
  segT s;
  char *p;
  offsetT size;
  const char *name;

  size = bfd_elf_obj_attr_size (stdoutput);
  if (size)
    {
      name = get_elf_backend_data (stdoutput)->obj_attrs_section;
      if (!name)
        name = ".gnu.attributes";
      s = subseg_new (name, 0);
      elf_section_type (s)
        = get_elf_backend_data (stdoutput)->obj_attrs_section_type;
      bfd_set_section_flags (stdoutput, s, SEC_READONLY | SEC_DATA);
      frag_now_fix ();
      p = frag_more (size);
      bfd_elf_set_obj_attr_contents (stdoutput, (bfd_byte *)p, size);

      subsegs_finish_section (s);
      relax_segment (seg_info (s)->frchainP->frch_root, s, 0);
      size_seg (stdoutput, s, NULL);
    }
}
#endif

/* Write the object file.  */

void
write_object_file (void)
{
  struct relax_seg_info rsi;
#ifndef WORKING_DOT_WORD
  fragS *fragP;                 /* Track along all frags.  */
#endif

  subsegs_finish ();

#ifdef md_pre_output_hook
  md_pre_output_hook;
#endif

#ifdef md_pre_relax_hook
  md_pre_relax_hook;
#endif

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

  /* Remove the sections created by gas for its own purposes.  */
  {
    int i;

    bfd_section_list_remove (stdoutput, reg_section);
    bfd_section_list_remove (stdoutput, expr_section);
    stdoutput->section_count -= 2;
    i = 0;
    bfd_map_over_sections (stdoutput, renumber_sections, &i);
  }

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

  /* 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 (flag_readonly_data_in_text)
    {
      merge_data_into_text ();
    }

  rsi.pass = 0;
  while (1)
    {
#ifndef WORKING_DOT_WORD
      /* We need to reset the markers in the broken word list and
         associated frags between calls to relax_segment (via
         relax_seg).  Since the broken word list is global, we do it
         once per round, rather than locally in relax_segment for each
         segment.  */
      struct broken_word *brokp;

      for (brokp = broken_words;
           brokp != (struct broken_word *) NULL;
           brokp = brokp->next_broken_word)
        {
          brokp->added = 0;

          if (brokp->dispfrag != (fragS *) NULL
              && brokp->dispfrag->fr_type == rs_broken_word)
            brokp->dispfrag->fr_subtype = 0;
        }
#endif

      rsi.changed = 0;
      bfd_map_over_sections (stdoutput, relax_seg, &rsi);
      rsi.pass++;
      if (!rsi.changed)
        break;
    }

  /* Note - Most ports will use the default value of
     TC_FINALIZE_SYMS_BEFORE_SIZE_SEG, which 1.  This will force
     local symbols to be resolved, removing their frag information.
     Some ports however, will not have finished relaxing all of
     their frags and will still need the local symbol frag
     information.  These ports can set
     TC_FINALIZE_SYMS_BEFORE_SIZE_SEG to 0.  */
  finalize_syms = TC_FINALIZE_SYMS_BEFORE_SIZE_SEG;

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

  /* Relaxation has completed.  Freeze all syms.  */
  finalize_syms = 1;

#ifdef md_post_relax_hook
  md_post_relax_hook;
#endif

#ifdef OBJ_ELF
  if (IS_ELF)
    create_obj_attrs_section ();
#endif

#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;

          subseg_change (lie->seg, lie->subseg);
          exp.X_op = O_subtract;
          exp.X_add_symbol = lie->add;
          exp.X_op_symbol = lie->sub;
          exp.X_add_number = lie->addnum;
#ifdef TC_CONS_FIX_NEW
          TC_CONS_FIX_NEW (lie->frag,
                           lie->word_goes_here - lie->frag->fr_literal,
                           2, &exp, TC_PARSE_CONS_RETURN_NONE);
#else
          fix_new_exp (lie->frag,
                       lie->word_goes_here - lie->frag->fr_literal,
                       2, &exp, 0, BFD_RELOC_16);
#endif
          *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;

        subseg_change (lie->seg, lie->subseg);
        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.  */
            for (untruth = (struct broken_word *) (fragP->fr_symbol);
                 untruth && untruth->dispfrag == fragP;
                 untruth = untruth->next_broken_word)
              {
                if (untruth->use_jump == lie)
                  {
                    /* This is the offset from ??? to table_ptr+0.
                       The target is the same for all users of this
                       md_long_jump, but the "sub" bases (and hence the
                       offsets) may be different.  */
                    addressT to_word = table_addr - S_GET_VALUE (untruth->sub);
#ifdef TC_CHECK_ADJUSTED_BROKEN_DOT_WORD
                    TC_CHECK_ADJUSTED_BROKEN_DOT_WORD (to_word, untruth);
#endif
                    md_number_to_chars (untruth->word_goes_here, to_word, 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  */

  /* Resolve symbol values.  This needs to be done before processing
     the relocations.  */
  if (symbol_rootP)
    {
      symbolS *symp;

      for (symp = symbol_rootP; symp; symp = symbol_next (symp))
        resolve_symbol_value (symp);
    }
  resolve_local_symbol_values ();
  resolve_reloc_expr_symbols ();

  PROGRESS (1);

#ifdef tc_frob_file_before_adjust
  tc_frob_file_before_adjust ();
#endif
#ifdef obj_frob_file_before_adjust
  obj_frob_file_before_adjust ();
#endif

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

#ifdef tc_frob_file_before_fix
  tc_frob_file_before_fix ();
#endif
#ifdef obj_frob_file_before_fix
  obj_frob_file_before_fix ();
#endif

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

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

      for (symp = symbol_rootP; symp; symp = symbol_next (symp))
        {
          int punt = 0;
          const char *name;

          if (skip_next_symbol)
            {
              /* Don't do anything besides moving the value of the
                 symbol from the GAS value-field to the BFD value-field.  */
              symbol_get_bfdsym (symp)->value = S_GET_VALUE (symp);
              skip_next_symbol = FALSE;
              continue;
            }

          if (symbol_mri_common_p (symp))
            {
              if (S_IS_EXTERNAL (symp))
                as_bad (_("%s: global symbols not supported in common sections"),
                        S_GET_NAME (symp));
              symbol_remove (symp, &symbol_rootP, &symbol_lastP);
              continue;
            }

          name = S_GET_NAME (symp);
          if (name)
            {
              const char *name2 =
                decode_local_label_name ((char *) S_GET_NAME (symp));
              /* They only differ if `name' is a fb or dollar local
                 label name.  */
              if (name2 != name && ! S_IS_DEFINED (symp))
                as_bad (_("local label `%s' is not defined"), name2);
            }

          /* Do it again, because adjust_reloc_syms might introduce
             more symbols.  They'll probably only be section symbols,
             but they'll still need to have the values computed.  */
          resolve_symbol_value (symp);

          /* Skip symbols which were equated to undefined or common
             symbols.  */
          if (symbol_equated_reloc_p (symp)
              || S_IS_WEAKREFR (symp))
            {
              const char *sname = S_GET_NAME (symp);

              if (S_IS_COMMON (symp)
                  && !TC_FAKE_LABEL (sname)
                  && !S_IS_WEAKREFR (symp)
                  && (!S_IS_EXTERNAL (symp) || S_IS_LOCAL (symp)))
                {
                  expressionS *e = symbol_get_value_expression (symp);

                  as_bad (_("Local symbol `%s' can't be equated to common symbol `%s'"),
                          sname, S_GET_NAME (e->X_add_symbol));
                }
              if (S_GET_SEGMENT (symp) == reg_section)
                {
                  /* Report error only if we know the symbol name.  */
                  if (S_GET_NAME (symp) != reg_section->name)
                    as_bad (_("can't make global register symbol `%s'"),
                            sname);
                }
              symbol_remove (symp, &symbol_rootP, &symbol_lastP);
              continue;
            }

#ifdef obj_frob_symbol
          obj_frob_symbol (symp, punt);
#endif
#ifdef tc_frob_symbol
          if (! punt || symbol_used_in_reloc_p (symp))
            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 (symp == abs_section_sym
              || (! EMIT_SECTION_SYMBOLS
                  && symbol_section_p (symp))
              /* Note that S_IS_EXTERNAL and S_IS_LOCAL are not always
                 opposites.  Sometimes the former checks flags and the
                 latter examines the name...  */
              || (!S_IS_EXTERNAL (symp)
                  && (punt || S_IS_LOCAL (symp) ||
                      (S_IS_WEAKREFD (symp) && ! symbol_used_p (symp)))
                  && ! symbol_used_in_reloc_p (symp)))
            {
              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 (! symbol_resolved_p (symp))
            {
              as_bad (_("can't resolve value for symbol `%s'"),
                      S_GET_NAME (symp));
              symbol_mark_resolved (symp);
            }

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

          /* A warning construct is a warning symbol followed by the
             symbol warned about.  Don't let anything object-format or
             target-specific muck with it; it's ready for output.  */
          if (symbol_get_bfdsym (symp)->flags & BSF_WARNING)
            skip_next_symbol = TRUE;
        }
    }

  PROGRESS (1);

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

  /* Stop if there is an error.  */
  if (had_errors ())
    return;

  /* 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
#ifdef obj_coff_generate_pdata
  obj_coff_generate_pdata ();
#endif
  bfd_map_over_sections (stdoutput, write_relocs, (char *) 0);

#ifdef tc_frob_file_after_relocs
  tc_frob_file_after_relocs ();
#endif
#ifdef obj_frob_file_after_relocs
  obj_frob_file_after_relocs ();
#endif

  /* Once all relocations have been written, we can compress the
     contents of the debug sections.  This needs to be done before
     we start writing any sections, because it will affect the file
     layout, which is fixed once we start writing contents.  */
  if (flag_compress_debug)
    bfd_map_over_sections (stdoutput, compress_debug, (char *) 0);

  bfd_map_over_sections (stdoutput, write_contents, (char *) 0);
}

#ifdef TC_GENERIC_RELAX_TABLE
/* Relax a fragment by scanning TC_GENERIC_RELAX_TABLE.  */

long
relax_frag (segT segment, fragS *fragP, long stretch)
{
  const relax_typeS *this_type;
  const relax_typeS *start_type;
  relax_substateT next_state;
  relax_substateT this_state;
  offsetT growth;
  offsetT aim;
  addressT target;
  addressT address;
  symbolS *symbolP;
  const relax_typeS *table;

  target = fragP->fr_offset;
  address = fragP->fr_address;
  table = TC_GENERIC_RELAX_TABLE;
  this_state = fragP->fr_subtype;
  start_type = this_type = table + this_state;
  symbolP = fragP->fr_symbol;

  if (symbolP)
    {
      fragS *sym_frag;

      sym_frag = symbol_get_frag (symbolP);

#ifndef DIFF_EXPR_OK
      know (sym_frag != NULL);
#endif
      know (S_GET_SEGMENT (symbolP) != absolute_section
            || sym_frag == &zero_address_frag);
      target += S_GET_VALUE (symbolP);

      /* If SYM_FRAG has yet to be reached on this pass, assume it
         will move by STRETCH just as we did, unless there is an
         alignment frag between here and SYM_FRAG.  An alignment may
         well absorb any STRETCH, and we don't want to choose a larger
         branch insn by overestimating the needed reach of this
         branch.  It isn't critical to calculate TARGET exactly;  We
         know we'll be doing another pass if STRETCH is non-zero.  */

      if (stretch != 0
          && sym_frag->relax_marker != fragP->relax_marker
          && S_GET_SEGMENT (symbolP) == segment)
        {
          if (stretch < 0
              || sym_frag->region == fragP->region)
            target += stretch;
          /* If we get here we know we have a forward branch.  This
             relax pass may have stretched previous instructions so
             far that omitting STRETCH would make the branch
             negative.  Don't allow this in case the negative reach is
             large enough to require a larger branch instruction.  */
          else if (target < address)
            target = fragP->fr_next->fr_address + stretch;
        }
    }

  aim = target - address - fragP->fr_fix;
#ifdef TC_PCREL_ADJUST
  /* Currently only the ns32k family needs this.  */
  aim += TC_PCREL_ADJUST (fragP);
#endif

#ifdef md_prepare_relax_scan
  /* Formerly called M68K_AIM_KLUDGE.  */
  md_prepare_relax_scan (fragP, address, aim, this_state, this_type);
#endif

  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 = table + this_state;
            next_state = this_type->rlx_more;
          }
    }
  else
    {
      /* 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 = 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;
  return growth;
}

#endif /* defined (TC_GENERIC_RELAX_TABLE)  */

/* 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 (register relax_addressT address,   /* Address now.  */
             register int alignment     /* Alignment (binary).  */)
{
  relax_addressT mask;
  relax_addressT new_address;

  mask = ~((relax_addressT) ~0 << alignment);
  new_address = (address + mask) & (~mask);
#ifdef LINKER_RELAXING_SHRINKS_ONLY
  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);
#endif
  return (new_address - address);
}

/* 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.  */

int
relax_segment (struct frag *segment_frag_root, segT segment, int pass)
{
  unsigned long frag_count;
  struct frag *fragP;
  relax_addressT address;
  int region;
  int ret;

  /* 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;
  region = 0;
  for (frag_count = 0, fragP = segment_frag_root;
       fragP;
       fragP = fragP->fr_next, frag_count ++)
    {
      fragP->region = region;
      fragP->relax_marker = 0;
      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:
        case rs_align_code:
        case rs_align_test:
          {
            addressT offset = relax_align (address, (int) fragP->fr_offset);

            if (fragP->fr_subtype != 0 && offset > fragP->fr_subtype)
              offset = 0;

            if (offset % fragP->fr_var != 0)
              {
                as_bad_where (fragP->fr_file, fragP->fr_line,
                              _("alignment padding (%lu bytes) not a multiple of %ld"),
                              (unsigned long) offset, (long) fragP->fr_var);
                offset -= (offset % fragP->fr_var);
              }

            address += offset;
            region += 1;
          }
          break;

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

        case rs_space:
          break;

        case rs_machine_dependent:
          /* If fr_symbol is an expression, this call to
             resolve_symbol_value sets up the correct segment, which will
             likely be needed in md_estimate_size_before_relax.  */
          if (fragP->fr_symbol)
            resolve_symbol_value (fragP->fr_symbol);

          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

        case rs_leb128:
          /* Initial guess is always 1; doing otherwise can result in
             stable solutions that are larger than the minimum.  */
          address += fragP->fr_offset = 1;
          break;

        case rs_cfa:
          address += eh_frame_estimate_size_before_relax (fragP);
          break;

        case rs_dwarf2dbg:
          address += dwarf2dbg_estimate_size_before_relax (fragP);
          break;

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

  /* Do relax().  */
  {
    unsigned long max_iterations;

    /* Cumulative address adjustment.  */
    offsetT stretch;

    /* Have we made any adjustment this pass?  We can't just test
       stretch because one piece of code may have grown and another
       shrank.  */
    int stretched;

    /* Most horrible, but gcc may give us some exception data that
       is impossible to assemble, of the form

       .align 4
       .byte 0, 0
       .uleb128 end - start
       start:
       .space 128*128 - 1
       .align 4
       end:

       If the leb128 is two bytes in size, then end-start is 128*128,
       which requires a three byte leb128.  If the leb128 is three
       bytes in size, then end-start is 128*128-1, which requires a
       two byte leb128.  We work around this dilemma by inserting
       an extra 4 bytes of alignment just after the .align.  This
       works because the data after the align is accessed relative to
       the end label.

       This counter is used in a tiny state machine to detect
       whether a leb128 followed by an align is impossible to
       relax.  */
    int rs_leb128_fudge = 0;

    /* We want to prevent going into an infinite loop where one frag grows
       depending upon the location of a symbol which is in turn moved by
       the growing frag.  eg:

         foo = .
         .org foo+16
         foo = .

       So we dictate that this algorithm can be at most O2.  */
    max_iterations = frag_count * frag_count;
    /* Check for overflow.  */
    if (max_iterations < frag_count)
      max_iterations = frag_count;

    ret = 0;
    do
      {
        stretch = 0;
        stretched = 0;

        for (fragP = segment_frag_root; fragP; fragP = fragP->fr_next)
          {
            offsetT growth = 0;
            addressT was_address;
            offsetT offset;
            symbolS *symbolP;

            fragP->relax_marker ^= 1;
            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 = (S_GET_VALUE (lie->add)
                                + lie->addnum
                                - 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_where (fragP->fr_file, fragP->fr_line,
                                             _(".word %s-%s+%s didn't fit"),
                                             S_GET_NAME (lie->add),
                                             S_GET_NAME (lie->sub),
                                             buf);
                            }
                          if (fragP->fr_subtype == 0)
                            {
                              fragP->fr_subtype++;
                              growth += md_short_jump_size;
                            }

                          /* Redirect *all* words of this table with the same
                             target, lest we have to handle the case where the
                             same target but with a offset that fits on this
                             round overflows at the next relaxation round.  */
                          for (untruth = (struct broken_word *) (fragP->fr_symbol);
                               untruth && untruth->dispfrag == lie->dispfrag;
                               untruth = untruth->next_broken_word)
                            if ((symbol_get_frag (untruth->add)
                                 == symbol_get_frag (lie->add))
                                && (S_GET_VALUE (untruth->add)
                                    == S_GET_VALUE (lie->add)))
                              {
                                untruth->added = 2;
                                untruth->use_jump = lie;
                              }

                          lie->added = 1;
                          growth += md_long_jump_size;
                        }
                    }

                  break;
                }               /* case rs_broken_word  */
#endif
              case rs_align:
              case rs_align_code:
              case rs_align_test:
                {
                  addressT oldoff, newoff;

                  oldoff = relax_align (was_address + fragP->fr_fix,
                                        (int) offset);
                  newoff = relax_align (address + fragP->fr_fix,
                                        (int) offset);

                  if (fragP->fr_subtype != 0)
                    {
                      if (oldoff > fragP->fr_subtype)
                        oldoff = 0;
                      if (newoff > fragP->fr_subtype)
                        newoff = 0;
                    }

                  growth = newoff - oldoff;

                  /* If this align happens to follow a leb128 and
                     we have determined that the leb128 is bouncing
                     in size, then break the cycle by inserting an
                     extra alignment.  */
                  if (growth < 0
                      && (rs_leb128_fudge & 16) != 0
                      && (rs_leb128_fudge & 15) >= 2)
                    {
                      segment_info_type *seginfo = seg_info (segment);
                      struct obstack *ob = &seginfo->frchainP->frch_obstack;
                      struct frag *newf;

                      newf = frag_alloc (ob);
                      obstack_blank_fast (ob, fragP->fr_var);
                      obstack_finish (ob);
                      memcpy (newf, fragP, SIZEOF_STRUCT_FRAG);
                      memcpy (newf->fr_literal,
                              fragP->fr_literal + fragP->fr_fix,
                              fragP->fr_var);
                      newf->fr_type = rs_fill;
                      newf->fr_address = address + fragP->fr_fix + newoff;
                      newf->fr_fix = 0;
                      newf->fr_offset = (((offsetT) 1 << fragP->fr_offset)
                                         / fragP->fr_var);
                      if (newf->fr_offset * newf->fr_var
                          != (offsetT) 1 << fragP->fr_offset)
                        {
                          newf->fr_offset = (offsetT) 1 << fragP->fr_offset;
                          newf->fr_var = 1;
                        }
                      /* Include size of new frag in GROWTH.  */
                      growth += newf->fr_offset * newf->fr_var;
                      /* Adjust the new frag address for the amount
                         we'll add when we process the new frag.  */
                      newf->fr_address -= stretch + growth;
                      newf->relax_marker ^= 1;
                      fragP->fr_next = newf;
#ifdef DEBUG
                      as_warn (_("padding added"));
#endif
                    }
                }
                break;

              case rs_org:
                {
                  addressT target = offset;
                  addressT after;

                  if (symbolP)
                    {
                      /* Convert from an actual address to an octet offset
                         into the section.  Here it is assumed that the
                         section's VMA is zero, and can omit subtracting it
                         from the symbol's value to get the address offset.  */
                      know (S_GET_SEGMENT (symbolP)->vma == 0);
                      target += S_GET_VALUE (symbolP) * OCTETS_PER_BYTE;
                    }

                  know (fragP->fr_next);
                  after = fragP->fr_next->fr_address + stretch;
                  growth = target - after;
                  if (growth < 0)
                    {
                      growth = 0;

                      /* Don't error on first few frag relax passes.
                         The symbol might be an expression involving
                         symbol values from other sections.  If those
                         sections have not yet been processed their
                         frags will all have zero addresses, so we
                         will calculate incorrect values for them.  The
                         number of passes we allow before giving an
                         error is somewhat arbitrary.  It should be at
                         least one, with larger values requiring
                         increasingly contrived dependencies between
                         frags to trigger a false error.  */
                      if (pass < 2)
                        {
                          /* Force another pass.  */
                          ret = 1;
                          break;
                        }

                      /* Growth may be negative, but variable part of frag
                         cannot have fewer than 0 chars.  That is, we can't
                         .org backwards.  */
                      as_bad_where (fragP->fr_file, fragP->fr_line,
                                    _("attempt to move .org backwards"));

                      /* We've issued an error message.  Change the
                         frag to avoid cascading errors.  */
                      fragP->fr_type = rs_align;
                      fragP->fr_subtype = 0;
                      fragP->fr_offset = 0;
                      fragP->fr_fix = after - address;
                    }
                }
                break;

              case rs_space:
                growth = 0;
                if (symbolP)
                  {
                    offsetT amount;

                    amount = S_GET_VALUE (symbolP);
                    if (S_GET_SEGMENT (symbolP) != absolute_section
                        || S_IS_COMMON (symbolP)
                        || ! S_IS_DEFINED (symbolP))
                      {
                        as_bad_where (fragP->fr_file, fragP->fr_line,
                                      _(".space specifies non-absolute value"));
                        /* Prevent repeat of this error message.  */
                        fragP->fr_symbol = 0;
                      }
                    else if (amount < 0)
                      {
                        /* Don't error on first few frag relax passes.
                           See rs_org comment for a longer explanation.  */
                        if (pass < 2)
                          {
                            ret = 1;
                            break;
                          }

                        as_warn_where (fragP->fr_file, fragP->fr_line,
                                       _(".space or .fill with negative value, ignored"));
                        fragP->fr_symbol = 0;
                      }
                    else
                      growth = (was_address + fragP->fr_fix + amount
                                - fragP->fr_next->fr_address);
                  }
                break;

              case rs_machine_dependent:
#ifdef md_relax_frag
                growth = md_relax_frag (segment, fragP, stretch);
#else
#ifdef TC_GENERIC_RELAX_TABLE
                /* The default way to relax a frag is to look through
                   TC_GENERIC_RELAX_TABLE.  */
                growth = relax_frag (segment, fragP, stretch);
#endif /* TC_GENERIC_RELAX_TABLE  */
#endif
                break;

              case rs_leb128:
                {
                  valueT value;
                  offsetT size;

                  value = resolve_symbol_value (fragP->fr_symbol);
                  size = sizeof_leb128 (value, fragP->fr_subtype);
                  growth = size - fragP->fr_offset;
                  fragP->fr_offset = size;
                }
                break;

              case rs_cfa:
                growth = eh_frame_relax_frag (fragP);
                break;

              case rs_dwarf2dbg:
                growth = dwarf2dbg_relax_frag (fragP);
                break;

              default:
                BAD_CASE (fragP->fr_type);
                break;
              }
            if (growth)
              {
                stretch += growth;
                stretched = 1;
                if (fragP->fr_type == rs_leb128)
                  rs_leb128_fudge += 16;
                else if (fragP->fr_type == rs_align
                         && (rs_leb128_fudge & 16) != 0
                         && stretch == 0)
                  rs_leb128_fudge += 16;
                else
                  rs_leb128_fudge = 0;
              }
          }

        if (stretch == 0
            && (rs_leb128_fudge & 16) == 0
            && (rs_leb128_fudge & -16) != 0)
          rs_leb128_fudge += 1;
        else
          rs_leb128_fudge = 0;
      }
    /* Until nothing further to relax.  */
    while (stretched && -- max_iterations);

    if (stretched)
      as_fatal (_("Infinite loop encountered whilst attempting to compute the addresses of symbols in section %s"),
                segment_name (segment));
  }

  for (fragP = segment_frag_root; fragP; fragP = fragP->fr_next)
    if (fragP->last_fr_address != fragP->fr_address)
      {
        fragP->last_fr_address = fragP->fr_address;
        ret = 1;
      }
  return ret;
}

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

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

void
write_print_statistics (FILE *file)
{
  fprintf (file, "fixups: %d\n", n_fixups);
}

/* For debugging.  */
extern int indent_level;

void
print_fixup (fixS *fixp)
{
  indent_level = 1;
  fprintf (stderr, "fix ");
  fprintf_vma (stderr, (bfd_vma)((bfd_hostptr_t) fixp));
  fprintf (stderr, " %s:%d",fixp->fx_file, fixp->fx_line);
  if (fixp->fx_pcrel)
    fprintf (stderr, " pcrel");
  if (fixp->fx_pcrel_adjust)
    fprintf (stderr, " pcrel_adjust=%d", fixp->fx_pcrel_adjust);
  if (fixp->fx_im_disp)
    {
#ifdef TC_NS32K
      fprintf (stderr, " im_disp=%d", fixp->fx_im_disp);
#else
      fprintf (stderr, " im_disp");
#endif
    }
  if (fixp->fx_tcbit)
    fprintf (stderr, " tcbit");
  if (fixp->fx_done)
    fprintf (stderr, " done");
  fprintf (stderr, "\n    size=%d frag=", fixp->fx_size);
  fprintf_vma (stderr, (bfd_vma) ((bfd_hostptr_t) fixp->fx_frag));
  fprintf (stderr, " where=%ld offset=%lx addnumber=%lx",
           (long) fixp->fx_where,
           (unsigned long) fixp->fx_offset,
           (unsigned long) fixp->fx_addnumber);
  fprintf (stderr, "\n    %s (%d)", bfd_get_reloc_code_name (fixp->fx_r_type),
           fixp->fx_r_type);
  if (fixp->fx_addsy)
    {
      fprintf (stderr, "\n   +<");
      print_symbol_value_1 (stderr, fixp->fx_addsy);
      fprintf (stderr, ">");
    }
  if (fixp->fx_subsy)
    {
      fprintf (stderr, "\n   -<");
      print_symbol_value_1 (stderr, fixp->fx_subsy);
      fprintf (stderr, ">");
    }
  fprintf (stderr, "\n");
#ifdef TC_FIX_DATA_PRINT
  TC_FIX_DATA_PRINT (stderr, fixp);
#endif
}