cofflink.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 2,243 行 · 第 1/5 页

	     FIXME: I don't think this will work in the case where
	     there are two object files which use the constants as a
	     literal and two object files which use it as a data
	     initializer.  One or the other of the second object files
	     is going to wind up with an inappropriate reference.  */
	  if (obj_pe (abfd)
	      && (classification == COFF_SYMBOL_GLOBAL
		  || classification == COFF_SYMBOL_PE_SECTION)
	      && section->comdat != NULL
	      && strncmp (name, "??_", 3) == 0
	      && strcmp (name, section->comdat->name) == 0)
	    {
	      if (*sym_hash == NULL)
		*sym_hash = coff_link_hash_lookup (coff_hash_table (info),
						   name, false, copy, false);
	      if (*sym_hash != NULL
		  && (*sym_hash)->root.type == bfd_link_hash_defined
		  && (*sym_hash)->root.u.def.section->comdat != NULL
		  && strcmp ((*sym_hash)->root.u.def.section->comdat->name,
			     section->comdat->name) == 0)
		addit = false;
	    }

	  if (addit)
	    {
	      if (! (bfd_coff_link_add_one_symbol
		     (info, abfd, name, flags, section, value,
		      (const char *) NULL, copy, false,
		      (struct bfd_link_hash_entry **) sym_hash)))
		goto error_return;
	    }

	  if (obj_pe (abfd) && (flags & BSF_SECTION_SYM) != 0)
	    (*sym_hash)->coff_link_hash_flags |=
	      COFF_LINK_HASH_PE_SECTION_SYMBOL;

	  /* Limit the alignment of a common symbol to the possible
             alignment of a section.  There is no point to permitting
             a higher alignment for a common symbol: we can not
             guarantee it, and it may cause us to allocate extra space
             in the common section.  */
	  if (section == bfd_com_section_ptr
	      && (*sym_hash)->root.type == bfd_link_hash_common
	      && ((*sym_hash)->root.u.c.p->alignment_power
		  > bfd_coff_default_section_alignment_power (abfd)))
	    (*sym_hash)->root.u.c.p->alignment_power
	      = bfd_coff_default_section_alignment_power (abfd);

	  if (info->hash->creator->flavour == bfd_get_flavour (abfd))
	    {
	      /* If we don't have any symbol information currently in
                 the hash table, or if we are looking at a symbol
                 definition, then update the symbol class and type in
                 the hash table.  */
  	      if (((*sym_hash)->class == C_NULL
  		   && (*sym_hash)->type == T_NULL)
  		  || sym.n_scnum != 0
  		  || (sym.n_value != 0
  		      && (*sym_hash)->root.type != bfd_link_hash_defined
  		      && (*sym_hash)->root.type != bfd_link_hash_defweak))
  		{
  		  (*sym_hash)->class = sym.n_sclass;
  		  if (sym.n_type != T_NULL)
  		    {
  		      /* We want to warn if the type changed, but not
  			 if it changed from an unspecified type.
  			 Testing the whole type byte may work, but the
  			 change from (e.g.) a function of unspecified
  			 type to function of known type also wants to
  			 skip the warning.  */
  		      if ((*sym_hash)->type != T_NULL
  			  && (*sym_hash)->type != sym.n_type
  		          && !(DTYPE ((*sym_hash)->type) == DTYPE (sym.n_type)
  		               && (BTYPE ((*sym_hash)->type) == T_NULL
  		                   || BTYPE (sym.n_type) == T_NULL)))
  			(*_bfd_error_handler)
  			  (_("Warning: type of symbol `%s' changed from %d to %d in %s"),
  			   name, (*sym_hash)->type, sym.n_type,
  			   bfd_get_filename (abfd));

  		      /* We don't want to change from a meaningful
  			 base type to a null one, but if we know
  			 nothing, take what little we might now know.  */
  		      if (BTYPE (sym.n_type) != T_NULL
  			  || (*sym_hash)->type == T_NULL)
			(*sym_hash)->type = sym.n_type;
  		    }
  		  (*sym_hash)->auxbfd = abfd;
		  if (sym.n_numaux != 0)
		    {
		      union internal_auxent *alloc;
		      unsigned int i;
		      bfd_byte *eaux;
		      union internal_auxent *iaux;

		      (*sym_hash)->numaux = sym.n_numaux;
		      alloc = ((union internal_auxent *)
			       bfd_hash_allocate (&info->hash->table,
						  (sym.n_numaux
						   * sizeof (*alloc))));
		      if (alloc == NULL)
			goto error_return;
		      for (i = 0, eaux = esym + symesz, iaux = alloc;
			   i < sym.n_numaux;
			   i++, eaux += symesz, iaux++)
			bfd_coff_swap_aux_in (abfd, (PTR) eaux, sym.n_type,
					      sym.n_sclass, i, sym.n_numaux,
					      (PTR) iaux);
		      (*sym_hash)->aux = alloc;
		    }
		}
	    }

	  if (classification == COFF_SYMBOL_PE_SECTION
	      && (*sym_hash)->numaux != 0)
	    {
	      /* Some PE sections (such as .bss) have a zero size in
                 the section header, but a non-zero size in the AUX
                 record.  Correct that here.

		 FIXME: This is not at all the right place to do this.
		 For example, it won't help objdump.  This needs to be
		 done when we swap in the section header.  */

	      BFD_ASSERT ((*sym_hash)->numaux == 1);
	      if (section->_raw_size == 0)
		section->_raw_size = (*sym_hash)->aux[0].x_scn.x_scnlen;

	      /* FIXME: We could test whether the section sizes
                 matches the size in the aux entry, but apparently
                 that sometimes fails unexpectedly.  */
	    }
	}

      esym += (sym.n_numaux + 1) * symesz;
      sym_hash += sym.n_numaux + 1;
    }

  /* If this is a non-traditional, non-relocateable link, try to
     optimize the handling of any .stab/.stabstr sections.  */
  if (! info->relocateable
      && ! info->traditional_format
      && info->hash->creator->flavour == bfd_get_flavour (abfd)
      && (info->strip != strip_all && info->strip != strip_debugger))
    {
      asection *stab, *stabstr;

      stab = bfd_get_section_by_name (abfd, ".stab");
      if (stab != NULL)
	{
	  stabstr = bfd_get_section_by_name (abfd, ".stabstr");

	  if (stabstr != NULL)
	    {
	      struct coff_link_hash_table *table;
	      struct coff_section_tdata *secdata;

	      secdata = coff_section_data (abfd, stab);
	      if (secdata == NULL)
		{
		  stab->used_by_bfd =
		    (PTR) bfd_zalloc (abfd,
				      sizeof (struct coff_section_tdata));
		  if (stab->used_by_bfd == NULL)
		    goto error_return;
		  secdata = coff_section_data (abfd, stab);
		}

	      table = coff_hash_table (info);

	      if (! _bfd_link_section_stabs (abfd, &table->stab_info,
					     stab, stabstr,
					     &secdata->stab_info))
		goto error_return;
	    }
	}
    }

  obj_coff_keep_syms (abfd) = keep_syms;

  return true;

 error_return:
  obj_coff_keep_syms (abfd) = keep_syms;
  return false;
}

/* Do the final link step.  */

boolean
_bfd_coff_final_link (abfd, info)
     bfd *abfd;
     struct bfd_link_info *info;
{
  bfd_size_type symesz;
  struct coff_final_link_info finfo;
  boolean debug_merge_allocated;
  boolean long_section_names;
  asection *o;
  struct bfd_link_order *p;
  size_t max_sym_count;
  size_t max_lineno_count;
  size_t max_reloc_count;
  size_t max_output_reloc_count;
  size_t max_contents_size;
  file_ptr rel_filepos;
  unsigned int relsz;
  file_ptr line_filepos;
  unsigned int linesz;
  bfd *sub;
  bfd_byte *external_relocs = NULL;
  char strbuf[STRING_SIZE_SIZE];

  symesz = bfd_coff_symesz (abfd);

  finfo.info = info;
  finfo.output_bfd = abfd;
  finfo.strtab = NULL;
  finfo.section_info = NULL;
  finfo.last_file_index = -1;
  finfo.last_bf_index = -1;
  finfo.internal_syms = NULL;
  finfo.sec_ptrs = NULL;
  finfo.sym_indices = NULL;
  finfo.outsyms = NULL;
  finfo.linenos = NULL;
  finfo.contents = NULL;
  finfo.external_relocs = NULL;
  finfo.internal_relocs = NULL;
  finfo.global_to_static = false;
  debug_merge_allocated = false;

  coff_data (abfd)->link_info = info;

  finfo.strtab = _bfd_stringtab_init ();
  if (finfo.strtab == NULL)
    goto error_return;

  if (! coff_debug_merge_hash_table_init (&finfo.debug_merge))
    goto error_return;
  debug_merge_allocated = true;

  /* Compute the file positions for all the sections.  */
  if (! abfd->output_has_begun)
    {
      if (! bfd_coff_compute_section_file_positions (abfd))
	goto error_return;
    }

  /* Count the line numbers and relocation entries required for the
     output file.  Set the file positions for the relocs.  */
  rel_filepos = obj_relocbase (abfd);
  relsz = bfd_coff_relsz (abfd);
  max_contents_size = 0;
  max_lineno_count = 0;
  max_reloc_count = 0;

  long_section_names = false;
  for (o = abfd->sections; o != NULL; o = o->next)
    {
      o->reloc_count = 0;
      o->lineno_count = 0;
      for (p = o->link_order_head; p != NULL; p = p->next)
	{
	  if (p->type == bfd_indirect_link_order)
	    {
	      asection *sec;

	      sec = p->u.indirect.section;

	      /* Mark all sections which are to be included in the
		 link.  This will normally be every section.  We need
		 to do this so that we can identify any sections which
		 the linker has decided to not include.  */
	      sec->linker_mark = true;

	      if (info->strip == strip_none
		  || info->strip == strip_some)
		o->lineno_count += sec->lineno_count;

	      if (info->relocateable)
		o->reloc_count += sec->reloc_count;

	      if (sec->_raw_size > max_contents_size)
		max_contents_size = sec->_raw_size;
	      if (sec->lineno_count > max_lineno_count)
		max_lineno_count = sec->lineno_count;
	      if (sec->reloc_count > max_reloc_count)
		max_reloc_count = sec->reloc_count;
	    }
	  else if (info->relocateable
		   && (p->type == bfd_section_reloc_link_order
		       || p->type == bfd_symbol_reloc_link_order))
	    ++o->reloc_count;
	}
      if (o->reloc_count == 0)
	o->rel_filepos = 0;
      else
	{
	  o->flags |= SEC_RELOC;
	  o->rel_filepos = rel_filepos;
	  rel_filepos += o->reloc_count * relsz;
	}

      if (bfd_coff_long_section_names (abfd)
	  && strlen (o->name) > SCNNMLEN)
	{
	  /* This section has a long name which must go in the string
             table.  This must correspond to the code in
             coff_write_object_contents which puts the string index
             into the s_name field of the section header.  That is why
             we pass hash as false.  */
	  if (_bfd_stringtab_add (finfo.strtab, o->name, false, false)
	      == (bfd_size_type) -1)
	    goto error_return;
	  long_section_names = true;
	}
    }

  /* If doing a relocateable link, allocate space for the pointers we
     need to keep.  */
  if (info->relocateable)
    {
      unsigned int i;

      /* We use section_count + 1, rather than section_count, because
         the target_index fields are 1 based.  */
      finfo.section_info =
	((struct coff_link_section_info *)
	 bfd_malloc ((abfd->section_count + 1)
		     * sizeof (struct coff_link_section_info)));
      if (finfo.section_info == NULL)
	goto error_return;
      for (i = 0; i <= abfd->section_count; i++)
	{
	  finfo.section_info[i].relocs = NULL;
	  finfo.section_info[i].rel_hashes = NULL;
	}
    }

  /* We now know the size of the relocs, so we can determine the file
     positions of the line numbers.  */
  line_filepos = rel_filepos;
  linesz = bfd_coff_linesz (abfd);
  max_output_reloc_count = 0;
  for (o = abfd->sections; o != NULL; o = o->next)
    {
      if (o->lineno_count == 0)
	o->line_filepos = 0;
      else
	{
	  o->line_filepos = line_filepos;
	  line_filepos += o->lineno_count * linesz;
	}

      if (o->reloc_count != 0)
	{
	  /* We don't know the indices of global symbols until we have
             written out all the local symbols.  For each section in
             the output file, we keep an array of pointers to hash
             table entries.  Each entry in the array corresponds to a
             reloc.  When we find a reloc against a global symbol, we
             set the corresponding entry in this array so that we can
             fix up the symbol index after we have written out all the
             local symbols.

	     Because of this problem, we also keep the relocs in
	     memory until the end of the link.  This wastes memory,
	     but only when doing a relocateable link, which is not the
	     common case.  */
	  BFD_ASSERT (info->relocateable);
	  finfo.section_info[o->target_index].relocs =
	    ((struct internal_reloc *)
	     bfd_malloc (o->reloc_count * sizeof (struct internal_reloc)));
	  finfo.section_info[o->target_index].rel_hashes =
	    ((struct coff_link_hash_entry **)
	     bfd_malloc (o->reloc_count
		     * sizeof (struct coff_link_hash_entry *)));
	  if (finfo.section_info[o->target_index].relocs == NULL
	      || finfo.section_info[o->target_index].rel_hashes == NULL)
	    goto error_return;

	  if (o->reloc_count > max_output_reloc_count)
	    max_output_reloc_count = o->reloc_count;
	}

      /* Reset the reloc and lineno counts, so that we can use them to
	 count the number of entries we have output so far.  */
      o->reloc_count = 0;
      o->lineno_count = 0;
    }

  obj_sym_filepos (abfd) = line_filepos;

  /* Figure out the largest number of symbols in an input BFD.  Take
     the opportunity to clear the output_has_begun fields of all the
     input BFD's.  */
  max_sym_count = 0;
  for (sub = info->input_bfds; sub != NULL; sub = sub->link_next)
    {
      size_t sz;

      sub->output_has_begun = false;
      sz = obj_raw_syment_count (sub);
      if (sz > max_sym_count)
	max_sym_count = sz;
    }

  /* Allocate some buffers used while linking.  */
  finfo.internal_syms = ((struct internal_syment *)
			 bfd_malloc (max_sym_count
				     * sizeof (struct internal_syment)));
  finfo.sec_ptrs = (asection **) bfd_malloc (max_sym_count
					     * sizeof (asection *));
  finfo.sym_indices = (long *) bfd_malloc (max_sym_count * sizeof (long));
  finfo.outsyms = ((bfd_byte *)
		   bfd_malloc ((size_t) ((max_sym_count + 1) * symesz)));
  finfo.linenos = (bfd_byte *) bfd_malloc (max_lineno_count
				       * bfd_coff_linesz (abfd));
  finfo.contents = (bfd_byte *) bfd_malloc (max_contents_size);
  finfo.external_relocs = (bfd_byte *) bfd_malloc (max_reloc_count * relsz);
  if (! info->relocateable)
    finfo.internal_relocs = ((struct internal_reloc *)
			     bfd_malloc (max_reloc_count
					 * sizeof (struct internal_reloc)));
  if ((finfo.internal_syms == NULL && max_sym_count > 0)
      || (finfo.sec_ptrs == NULL && max_sym_count > 0)
      || (finfo.sym_indices == NULL && max_sym_count > 0)
      || finfo.outsyms == NULL
      || (finfo.linenos == NULL && max_lineno_count > 0)
      || (finfo.contents == NULL && max_contents_size > 0)
      || (finfo.external_relocs == NULL && max_reloc_count > 0)
      || (! info->relocateable
	  && finfo.internal_relocs == NULL
	  && max_reloc_count > 0))
    goto error_return;

  /* We now know the position of everything in the file, except that
     we don't know the size of the symbol table and therefore we don't
     know where the string table starts.  We just build the string
     table in memory as we go along.  We process all the relocations
     for a single input file at once.  */
  obj_raw_syment_count (abfd) = 0;

  if (coff_backend_info (abfd)->_bfd_coff_start_final_link)
    {
      if (! bfd_coff_start_final_link (abfd, info))
	goto error_return;