elf32-i370.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 1,723 行 · 第 1/4 页

	    {
	      asection *target;
	      const char *outname;

	      /* Remember whether there are any relocation sections.  */
	      relocs = true;

	      /* If this relocation section applies to a read only
		 section, then we probably need a DT_TEXTREL entry.  */
	      outname = bfd_get_section_name (output_bfd,
					      s->output_section);
	      target = bfd_get_section_by_name (output_bfd, outname + 5);
	      if (target != NULL
		  && (target->flags & SEC_READONLY) != 0
		  && (target->flags & SEC_ALLOC) != 0)
		reltext = true;

	      /* We use the reloc_count field as a counter if we need
		 to copy relocs into the output file.  */
	      s->reloc_count = 0;
	    }
	}
      else if (strcmp (name, ".got") != 0
	       && strcmp (name, ".sdata") != 0
	       && strcmp (name, ".sdata2") != 0)
	{
	  /* It's not one of our sections, so don't allocate space.  */
	  continue;
	}

      if (strip)
	{
	  asection **spp;

	  for (spp = &s->output_section->owner->sections;
	       *spp != s->output_section;
	       spp = &(*spp)->next)
	    ;
	  *spp = s->output_section->next;
	  --s->output_section->owner->section_count;

	  continue;
	}
      /* Allocate memory for the section contents.  */
      s->contents = (bfd_byte *) bfd_zalloc (dynobj, s->_raw_size);
      if (s->contents == NULL && s->_raw_size != 0)
	return false;
    }

  if (elf_hash_table (info)->dynamic_sections_created)
    {
      /* Add some entries to the .dynamic section.  We fill in the
	 values later, in i370_elf_finish_dynamic_sections, but we
	 must add the entries now so that we get the correct size for
	 the .dynamic section.  The DT_DEBUG entry is filled in by the
	 dynamic linker and used by the debugger.  */
      if (! info->shared)
	{
	  if (! bfd_elf32_add_dynamic_entry (info, DT_DEBUG, 0))
	    return false;
	}

      if (plt)
	{
	  if (! bfd_elf32_add_dynamic_entry (info, DT_PLTGOT, 0)
	      || ! bfd_elf32_add_dynamic_entry (info, DT_PLTRELSZ, 0)
	      || ! bfd_elf32_add_dynamic_entry (info, DT_PLTREL, DT_RELA)
	      || ! bfd_elf32_add_dynamic_entry (info, DT_JMPREL, 0))
	    return false;
	}

      if (relocs)
	{
	  if (! bfd_elf32_add_dynamic_entry (info, DT_RELA, 0)
	      || ! bfd_elf32_add_dynamic_entry (info, DT_RELASZ, 0)
	      || ! bfd_elf32_add_dynamic_entry (info, DT_RELAENT,
						sizeof (Elf32_External_Rela)))
	    return false;
	}

      if (reltext)
	{
	  if (! bfd_elf32_add_dynamic_entry (info, DT_TEXTREL, 0))
	    return false;
	  info->flags |= DF_TEXTREL;
	}
    }

  /* If we are generating a shared library, we generate a section
     symbol for each output section.  These are local symbols, which
     means that they must come first in the dynamic symbol table.
     That means we must increment the dynamic symbol index of every
     other dynamic symbol.

     FIXME: We assume that there will never be relocations to
     locations in linker-created sections that do not have
     externally-visible names. Instead, we should work out precisely
     which sections relocations are targetted at.  */
  if (info->shared)
    {
      int c;

      for (c = 0, s = output_bfd->sections; s != NULL; s = s->next)
	{
	  if ((s->flags & SEC_LINKER_CREATED) != 0
	      || (s->flags & SEC_ALLOC) == 0)
	    {
	      elf_section_data (s)->dynindx = -1;
	      continue;
	    }

	  /* These symbols will have no names, so we don't need to
	     fiddle with dynstr_index.  */

	  elf_section_data (s)->dynindx = c + 1;

	  c++;
	}

      elf_link_hash_traverse (elf_hash_table (info),
			      i370_elf_adjust_dynindx,
			      (PTR) &c);
      elf_hash_table (info)->dynsymcount += c;
    }

  return true;
}

/* Look through the relocs for a section during the first phase, and
   allocate space in the global offset table or procedure linkage
   table.  */
/* XXX hack alert bogus This routine is mostly all junk and almost
 * certainly does the wrong thing.  Its here simply because it does
 * just enough to allow glibc-2.1 ld.so to compile & link.
 */

static boolean
i370_elf_check_relocs (abfd, info, sec, relocs)
     bfd *abfd;
     struct bfd_link_info *info;
     asection *sec;
     const Elf_Internal_Rela *relocs;
{
  bfd *dynobj;
  Elf_Internal_Shdr *symtab_hdr;
  struct elf_link_hash_entry **sym_hashes;
  const Elf_Internal_Rela *rel;
  const Elf_Internal_Rela *rel_end;
  bfd_vma *local_got_offsets;
  asection *sreloc;

  if (info->relocateable)
    return true;

#ifdef DEBUG
  fprintf (stderr, "i370_elf_check_relocs called for section %s in %s\n",
	   bfd_get_section_name (abfd, sec),
	   bfd_get_filename (abfd));
#endif

  dynobj = elf_hash_table (info)->dynobj;
  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);
  local_got_offsets = elf_local_got_offsets (abfd);

  sreloc = NULL;

  rel_end = relocs + sec->reloc_count;
  for (rel = relocs; rel < rel_end; rel++)
    {
      unsigned long r_symndx;
      struct elf_link_hash_entry *h;

      r_symndx = ELF32_R_SYM (rel->r_info);
      if (r_symndx < symtab_hdr->sh_info)
	h = NULL;
      else
	h = sym_hashes[r_symndx - symtab_hdr->sh_info];

      if (info->shared)
	{
#ifdef DEBUG
	  fprintf (stderr,
		   "i370_elf_check_relocs needs to create relocation for %s\n",
		   (h && h->root.root.string)
		   ? h->root.root.string : "<unknown>");
#endif
	  if (sreloc == NULL)
	    {
	      const char *name;

	      name = (bfd_elf_string_from_elf_section
		      (abfd,
		       elf_elfheader (abfd)->e_shstrndx,
		       elf_section_data (sec)->rel_hdr.sh_name));
	      if (name == NULL)
		return false;

	      BFD_ASSERT (strncmp (name, ".rela", 5) == 0
			  && strcmp (bfd_get_section_name (abfd, sec), name + 5) == 0);

	      sreloc = bfd_get_section_by_name (dynobj, name);
	      if (sreloc == NULL)
		{
		  flagword flags;

		  sreloc = bfd_make_section (dynobj, name);
		  flags = (SEC_HAS_CONTENTS | SEC_READONLY
			   | SEC_IN_MEMORY | SEC_LINKER_CREATED);
		  if ((sec->flags & SEC_ALLOC) != 0)
		    flags |= SEC_ALLOC | SEC_LOAD;
		  if (sreloc == NULL
		      || ! bfd_set_section_flags (dynobj, sreloc, flags)
		      || ! bfd_set_section_alignment (dynobj, sreloc, 2))
		    return false;
		}
	    }

	  sreloc->_raw_size += sizeof (Elf32_External_Rela);

	  /* FIXME: We should here do what the m68k and i386
	     backends do: if the reloc is pc-relative, record it
	     in case it turns out that the reloc is unnecessary
	     because the symbol is forced local by versioning or
	     we are linking with -Bdynamic.  Fortunately this
	     case is not frequent.  */
	}
    }

  return true;
}

/* Finish up the dynamic sections.  */
/* XXX hack alert bogus This routine is mostly all junk and almost
 * certainly does the wrong thing.  Its here simply because it does
 * just enough to allow glibc-2.1 ld.so to compile & link.
 */

static boolean
i370_elf_finish_dynamic_sections (output_bfd, info)
     bfd *output_bfd;
     struct bfd_link_info *info;
{
  asection *sdyn;
  bfd *dynobj = elf_hash_table (info)->dynobj;
  asection *sgot = bfd_get_section_by_name (dynobj, ".got");

#ifdef DEBUG
  fprintf (stderr, "i370_elf_finish_dynamic_sections called\n");
#endif

  sdyn = bfd_get_section_by_name (dynobj, ".dynamic");

  if (elf_hash_table (info)->dynamic_sections_created)
    {
      asection *splt;
      Elf32_External_Dyn *dyncon, *dynconend;

      splt = bfd_get_section_by_name (dynobj, ".plt");
      BFD_ASSERT (splt != NULL && sdyn != NULL);

      dyncon = (Elf32_External_Dyn *) sdyn->contents;
      dynconend = (Elf32_External_Dyn *) (sdyn->contents + sdyn->_raw_size);
      for (; dyncon < dynconend; dyncon++)
	{
	  Elf_Internal_Dyn dyn;
	  const char *name;
	  boolean size;

	  bfd_elf32_swap_dyn_in (dynobj, dyncon, &dyn);

	  switch (dyn.d_tag)
	    {
	    case DT_PLTGOT:   name = ".plt";	  size = false; break;
	    case DT_PLTRELSZ: name = ".rela.plt"; size = true;  break;
	    case DT_JMPREL:   name = ".rela.plt"; size = false; break;
	    default:	      name = NULL;	  size = false; break;
	    }

	  if (name != NULL)
	    {
	      asection *s;

	      s = bfd_get_section_by_name (output_bfd, name);
	      if (s == NULL)
		dyn.d_un.d_val = 0;
	      else
		{
		  if (! size)
		    dyn.d_un.d_ptr = s->vma;
		  else
		    {
		      if (s->_cooked_size != 0)
			dyn.d_un.d_val = s->_cooked_size;
		      else
			dyn.d_un.d_val = s->_raw_size;
		    }
		}
	      bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
	    }
	}
    }

  /* Add a blrl instruction at _GLOBAL_OFFSET_TABLE_-4 so that a function can
     easily find the address of the _GLOBAL_OFFSET_TABLE_.  */
/* XXX this is clearly very wrong for the 370 arch */
  if (sgot)
    {
      unsigned char *contents = sgot->contents;
      bfd_put_32 (output_bfd, 0x4e800021 /* blrl */, contents);

      if (sdyn == NULL)
	bfd_put_32 (output_bfd, (bfd_vma) 0, contents+4);
      else
	bfd_put_32 (output_bfd,
		    sdyn->output_section->vma + sdyn->output_offset,
		    contents+4);

      elf_section_data (sgot->output_section)->this_hdr.sh_entsize = 4;
    }

  if (info->shared)
    {
      asection *sdynsym;
      asection *s;
      Elf_Internal_Sym sym;
      int maxdindx = 0;

      /* Set up the section symbols for the output sections.  */

      sdynsym = bfd_get_section_by_name (dynobj, ".dynsym");
      BFD_ASSERT (sdynsym != NULL);

      sym.st_size = 0;
      sym.st_name = 0;
      sym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION);
      sym.st_other = 0;

      for (s = output_bfd->sections; s != NULL; s = s->next)
	{
	  int indx, dindx;

	  sym.st_value = s->vma;

	  indx = elf_section_data (s)->this_idx;
	  dindx = elf_section_data (s)->dynindx;
	  if (dindx != -1)
	    {
	      BFD_ASSERT(indx > 0);
	      BFD_ASSERT(dindx > 0);

	      if (dindx > maxdindx)
		maxdindx = dindx;

	      sym.st_shndx = indx;

	      bfd_elf32_swap_symbol_out (output_bfd, &sym,
					 (PTR) (((Elf32_External_Sym *)
						 sdynsym->contents)
						+ dindx));
	    }
	}

      /* Set the sh_info field of the output .dynsym section to the
         index of the first global symbol.  */
      elf_section_data (sdynsym->output_section)->this_hdr.sh_info =
	maxdindx + 1;
    }

  return true;
}

/* The RELOCATE_SECTION function is called by the ELF backend linker
   to handle the relocations for a section.

   The relocs are always passed as Rela structures; if the section
   actually uses Rel structures, the r_addend field will always be
   zero.

   This function is responsible for adjust the section contents as
   necessary, and (if using Rela relocs and generating a
   relocateable output file) adjusting the reloc addend as
   necessary.

   This function does not have to worry about setting the reloc
   address or the reloc symbol index.

   LOCAL_SYMS is a pointer to the swapped in local symbols.

   LOCAL_SECTIONS is an array giving the section in the input file
   corresponding to the st_shndx field of each local symbol.

   The global hash table entry for the global symbols can be found
   via elf_sym_hashes (input_bfd).

   When generating relocateable output, this function must handle
   STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
   going to be the section symbol corresponding to the output
   section, which means that the addend must be adjusted
   accordingly.  */

static boolean
i370_elf_relocate_section (output_bfd, info, input_bfd, input_section,
			  contents, relocs, local_syms, local_sections)
     bfd *output_bfd;
     struct bfd_link_info *info;
     bfd *input_bfd;
     asection *input_section;
     bfd_byte *contents;
     Elf_Internal_Rela *relocs;
     Elf_Internal_Sym *local_syms;
     asection **local_sections;
{
  Elf_Internal_Shdr *symtab_hdr		  = &elf_tdata (input_bfd)->symtab_hdr;
  struct elf_link_hash_entry **sym_hashes = elf_sym_hashes (input_bfd);
  bfd *dynobj				  = elf_hash_table (info)->dynobj;
  Elf_Internal_Rela *rel		  = relocs;
  Elf_Internal_Rela *relend		  = relocs + input_section->reloc_count;
  asection *sreloc			  = NULL;
  bfd_vma *local_got_offsets;
  boolean ret				  = true;

#ifdef DEBUG
  fprintf (stderr, "i370_elf_relocate_section called for %s section %s, %ld relocations%s\n",
	   bfd_get_filename (input_bfd),
	   bfd_section_name(input_bfd, input_section),
	   (long)input_section->reloc_count,
	   (info->relocateable) ? " (relocatable)" : "");
#endif

  if (!i370_elf_howto_table[ R_I370_ADDR31 ])	/* Initialize howto table if needed */