write.c

基于4个mips核的noc设计

      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);
    }
}

/* Write the object file.  */

void
write_object_file ()
{
#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 /* OBJ_VMS  */

  /* 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;
    int i;

    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;
      }
    i = 0;
    bfd_map_over_sections (stdoutput, renumber_sections, &i);
  }

  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_seg, (char *) 1);
  bfd_map_over_sections (stdoutput, relax_seg, (char *) 0);
  bfd_map_over_sections (stdoutput, size_seg, (char *) 0);
#else
  relax_and_size_all_segments ();
#endif /* BFD_ASSEMBLER  */

#if defined (BFD_ASSEMBLER) && defined (OBJ_COFF) && defined (TE_GO32)
  /* Now that the segments have their final sizes, run through the
     sections and set their vma and lma. !BFD gas sets them, and BFD gas
     should too. Currently, only DJGPP uses this code, but other
     COFF targets may need to execute this too.  */
  bfd_map_over_sections (stdoutput, set_segment_vma, (char *) 0);
#endif

#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)
    {
      /* At this point we have linked all the frags into a single
         chain.  However, cvt_frag_to_fill may call md_convert_frag
         which may call fix_new.  We need to ensure that fix_new adds
         the fixup to the right section.  */
      if (fragP == data_frag_root)
	subseg_change (SEG_DATA, 0);

      cvt_frag_to_fill (&headers, SEG_TEXT, 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;

	  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 BFD_ASSEMBLER
#ifdef TC_CONS_FIX_NEW
	  TC_CONS_FIX_NEW (lie->frag,
			   lie->word_goes_here - lie->frag->fr_literal,
			   2, &exp);
#else
	  fix_new_exp (lie->frag,
		       lie->word_goes_here - lie->frag->fr_literal,
		       2, &exp, 0, BFD_RELOC_16);
#endif
#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;

	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.  */
	    /* This is the offset from ??? to table_ptr+0.  */
	    to_addr = table_addr - S_GET_VALUE (lie->sub);
#ifdef BFD_ASSEMBLER
	    to_addr -= symbol_get_frag (lie->sub)->fr_address;
#endif
#ifdef TC_CHECK_ADJUSTED_BROKEN_DOT_WORD
	    TC_CHECK_ADJUSTED_BROKEN_DOT_WORD (to_addr, lie);
#endif
	    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;
#ifdef BFD_ASSEMBLER
	    to_addr += symbol_get_frag (lie->add)->fr_address;
#endif
	    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  */
    char *the_object_file;
    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;

	PROGRESS (1);
	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);
      }

    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);

#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);
    free (the_object_file);
#endif
  }
#else /* OBJ_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 /* OBJ_VMS  */
#else /* BFD_ASSEMBLER  */

  /* 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, 1);
    }
  resolve_local_symbol_values ();

  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);

  /* 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;
	  const char *name;

	  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, 1);

	  /* Skip symbols which were equated to undefined or common
             symbols.  */