elf32-m68k.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 2,163 行 · 第 1/5 页

      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;
	}
    }

  return true;
}

/* This function is called via elf_m68k_link_hash_traverse if we are
   creating a shared object with -Bsymbolic.  It discards the space
   allocated to copy PC relative relocs against symbols which are defined
   in regular objects.  We allocated space for them in the check_relocs
   routine, but we won't fill them in in the relocate_section routine.  */

static boolean
elf_m68k_discard_copies (h, ignore)
     struct elf_m68k_link_hash_entry *h;
     PTR ignore ATTRIBUTE_UNUSED;
{
  struct elf_m68k_pcrel_relocs_copied *s;

  /* We only discard relocs for symbols defined in a regular object.  */
  if ((h->root.elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
    return true;

  for (s = h->pcrel_relocs_copied; s != NULL; s = s->next)
    s->section->_raw_size -= s->count * sizeof (Elf32_External_Rela);

  return true;
}

/* Relocate an M68K ELF section.  */

static boolean
elf_m68k_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;
{
  bfd *dynobj;
  Elf_Internal_Shdr *symtab_hdr;
  struct elf_link_hash_entry **sym_hashes;
  bfd_vma *local_got_offsets;
  asection *sgot;
  asection *splt;
  asection *sreloc;
  Elf_Internal_Rela *rel;
  Elf_Internal_Rela *relend;

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

  sgot = NULL;
  splt = NULL;
  sreloc = NULL;

  rel = relocs;
  relend = relocs + input_section->reloc_count;
  for (; rel < relend; rel++)
    {
      int r_type;
      reloc_howto_type *howto;
      unsigned long r_symndx;
      struct elf_link_hash_entry *h;
      Elf_Internal_Sym *sym;
      asection *sec;
      bfd_vma relocation;
      bfd_reloc_status_type r;

      r_type = ELF32_R_TYPE (rel->r_info);
      if (r_type < 0 || r_type >= (int) R_68K_max)
	{
	  bfd_set_error (bfd_error_bad_value);
	  return false;
	}
      howto = howto_table + r_type;

      r_symndx = ELF32_R_SYM (rel->r_info);

      if (info->relocateable)
	{
	  /* This is a relocateable link.  We don't have to change
	     anything, unless the reloc is against a section symbol,
	     in which case we have to adjust according to where the
	     section symbol winds up in the output section.  */
	  if (r_symndx < symtab_hdr->sh_info)
	    {
	      sym = local_syms + r_symndx;
	      if (ELF_ST_TYPE (sym->st_info) == STT_SECTION)
		{
		  sec = local_sections[r_symndx];
		  rel->r_addend += sec->output_offset + sym->st_value;
		}
	    }

	  continue;
	}

      /* This is a final link.  */
      h = NULL;
      sym = NULL;
      sec = NULL;
      if (r_symndx < symtab_hdr->sh_info)
	{
	  sym = local_syms + r_symndx;
	  sec = local_sections[r_symndx];
	  relocation = (sec->output_section->vma
			+ sec->output_offset
			+ sym->st_value);
	}
      else
	{
	  h = sym_hashes[r_symndx - symtab_hdr->sh_info];
	  while (h->root.type == bfd_link_hash_indirect
		 || h->root.type == bfd_link_hash_warning)
	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
	  if (h->root.type == bfd_link_hash_defined
	      || h->root.type == bfd_link_hash_defweak)
	    {
	      sec = h->root.u.def.section;
	      if (((r_type == R_68K_PLT8
		    || r_type == R_68K_PLT16
		    || r_type == R_68K_PLT32
		    || r_type == R_68K_PLT8O
		    || r_type == R_68K_PLT16O
		    || r_type == R_68K_PLT32O)
		   && h->plt.offset != (bfd_vma) -1
		   && elf_hash_table (info)->dynamic_sections_created)
		  || ((r_type == R_68K_GOT8O
		       || r_type == R_68K_GOT16O
		       || r_type == R_68K_GOT32O
		       || ((r_type == R_68K_GOT8
			    || r_type == R_68K_GOT16
			    || r_type == R_68K_GOT32)
			   && strcmp (h->root.root.string,
				      "_GLOBAL_OFFSET_TABLE_") != 0))
		      && elf_hash_table (info)->dynamic_sections_created
		      && (! info->shared
			  || (! info->symbolic && h->dynindx != -1)
			  || (h->elf_link_hash_flags
			      & ELF_LINK_HASH_DEF_REGULAR) == 0))
		  || (info->shared
		      && ((! info->symbolic && h->dynindx != -1)
			  || (h->elf_link_hash_flags
			      & ELF_LINK_HASH_DEF_REGULAR) == 0)
		      && ((input_section->flags & SEC_ALLOC) != 0
			  /* DWARF will emit R_68K_32 relocations in its
			     sections against symbols defined externally
			     in shared libraries.  We can't do anything
			     with them here.  */
			  || ((input_section->flags & SEC_DEBUGGING) != 0
			      && (h->elf_link_hash_flags
				  & ELF_LINK_HASH_DEF_DYNAMIC) != 0))
		      && (r_type == R_68K_8
			  || r_type == R_68K_16
			  || r_type == R_68K_32
			  || r_type == R_68K_PC8
			  || r_type == R_68K_PC16
			  || r_type == R_68K_PC32)))
		{
		  /* In these cases, we don't need the relocation
		     value.  We check specially because in some
		     obscure cases sec->output_section will be NULL.  */
		  relocation = 0;
		}
	      else
		relocation = (h->root.u.def.value
			      + sec->output_section->vma
			      + sec->output_offset);
	    }
	  else if (h->root.type == bfd_link_hash_undefweak)
	    relocation = 0;
	  else if (info->shared && !info->symbolic
		   && !info->no_undefined
		   && ELF_ST_VISIBILITY (h->other) == STV_DEFAULT)
	    relocation = 0;
	  else
	    {
	      if (!(info->callbacks->undefined_symbol
		    (info, h->root.root.string, input_bfd,
		     input_section, rel->r_offset,
		     (!info->shared || info->no_undefined
		      || ELF_ST_VISIBILITY (h->other)))))
		return false;
	      relocation = 0;
	    }
	}

      switch (r_type)
	{
	case R_68K_GOT8:
	case R_68K_GOT16:
	case R_68K_GOT32:
	  /* Relocation is to the address of the entry for this symbol
	     in the global offset table.  */
	  if (h != NULL
	      && strcmp (h->root.root.string, "_GLOBAL_OFFSET_TABLE_") == 0)
	    break;
	  /* Fall through.  */
	case R_68K_GOT8O:
	case R_68K_GOT16O:
	case R_68K_GOT32O:
	  /* Relocation is the offset of the entry for this symbol in
	     the global offset table.  */

	  {
	    bfd_vma off;

	    if (sgot == NULL)
	      {
		sgot = bfd_get_section_by_name (dynobj, ".got");
		BFD_ASSERT (sgot != NULL);
	      }

	    if (h != NULL)
	      {
		off = h->got.offset;
		BFD_ASSERT (off != (bfd_vma) -1);

		if (!elf_hash_table (info)->dynamic_sections_created
		    || (info->shared
			&& (info->symbolic || h->dynindx == -1)
			&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR)))
		  {
		    /* This is actually a static link, or it is a
		       -Bsymbolic link and the symbol is defined
		       locally, or the symbol was forced to be local
		       because of a version file..  We must initialize
		       this entry in the global offset table.  Since
		       the offset must always be a multiple of 4, we
		       use the least significant bit to record whether
		       we have initialized it already.

		       When doing a dynamic link, we create a .rela.got
		       relocation entry to initialize the value.  This
		       is done in the finish_dynamic_symbol routine.  */
		    if ((off & 1) != 0)
		      off &= ~1;
		    else
		      {
			bfd_put_32 (output_bfd, relocation,
				    sgot->contents + off);
			h->got.offset |= 1;
		      }
		  }
	      }
	    else
	      {
		BFD_ASSERT (local_got_offsets != NULL
			    && local_got_offsets[r_symndx] != (bfd_vma) -1);

		off = local_got_offsets[r_symndx];

		/* The offset must always be a multiple of 4.  We use
		   the least significant bit to record whether we have
		   already generated the necessary reloc.  */
		if ((off & 1) != 0)
		  off &= ~1;
		else
		  {
		    bfd_put_32 (output_bfd, relocation, sgot->contents + off);

		    if (info->shared)
		      {
			asection *srelgot;
			Elf_Internal_Rela outrel;

			srelgot = bfd_get_section_by_name (dynobj, ".rela.got");
			BFD_ASSERT (srelgot != NULL);

			outrel.r_offset = (sgot->output_section->vma
					   + sgot->output_offset
					   + off);
			outrel.r_info = ELF32_R_INFO (0, R_68K_RELATIVE);
			outrel.r_addend = relocation;
			bfd_elf32_swap_reloca_out (output_bfd, &outrel,
						   (((Elf32_External_Rela *)
						     srelgot->contents)
						    + srelgot->reloc_count));
			++srelgot->reloc_count;
		      }

		    local_got_offsets[r_symndx] |= 1;
		  }
	      }

	    relocation = sgot->output_offset + off;
	    if (r_type == R_68K_GOT8O
		|| r_type == R_68K_GOT16O
		|| r_type == R_68K_GOT32O)
	      {
		/* This relocation does not use the addend.  */
		rel->r_addend = 0;
	      }
	    else
	      relocation += sgot->output_section->vma;
	  }
	  break;

	case R_68K_PLT8:
	case R_68K_PLT16:
	case R_68K_PLT32:
	  /* Relocation is to the entry for this symbol in the
	     procedure linkage table.  */

	  /* Resolve a PLTxx reloc against a local symbol directly,
	     without using the procedure linkage table.  */
	  if (h == NULL)
	    break;

	  if (h->plt.offset == (bfd_vma) -1
	      || !elf_hash_table (info)->dynamic_sections_created)
	    {
	      /* We didn't make a PLT entry for this symbol.  This
		 happens when statically linking PIC code, or when
		 using -Bsymbolic.  */
	      break;
	    }

	  if (splt == NULL)
	    {
	      splt = bfd_get_section_by_name (dynobj, ".plt");
	      BFD_ASSERT (splt != NULL);
	    }

	  relocation = (splt->output_section->vma
			+ splt->output_offset
			+ h->plt.offset);
	  break;

	case R_68K_PLT8O:
	case R_68K_PLT16O:
	case R_68K_PLT32O:
	  /* Relocation is the offset of the entry for this symbol in
	     the procedure linkage table.  */
	  BFD_ASSERT (h != NULL && h->plt.offset != (bfd_vma) -1);

	  if (splt == NULL)
	    {
	      splt = bfd_get_section_by_name (dynobj, ".plt");
	      BFD_ASSERT (splt != NULL);
	    }

	  relocation = h->plt.offset;

	  /* This relocation does not use the addend.  */
	  rel->r_addend = 0;

	  break;

	case R_68K_PC8:
	case R_68K_PC16:
	case R_68K_PC32:
	  if (h == NULL)
	    break;
	  /* Fall through.  */
	case R_68K_8:
	case R_68K_16:
	case R_68K_32:
	  if (info->shared
	      && (input_section->flags & SEC_ALLOC) != 0
	      && ((r_type != R_68K_PC8
		   && r_type != R_68K_PC16
		   && r_type != R_68K_PC32)
		  || (!info->symbolic
		      || (h->elf_link_hash_flags
			  & ELF_LINK_HASH_DEF_REGULAR) == 0)))
	    {
	      Elf_Internal_Rela outrel;
	      boolean skip, relocate;

	      /* When generating a shared object, these relocations
		 are copied into the output file to be resolved at run
		 time.  */

	      if (sreloc == NULL)
		{
		  const char *name;

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

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

		  sreloc = bfd_get_section_by_name (dynobj, name);
		  BFD_ASSERT (sreloc != NULL);
		}

	      skip = false;

	      if (elf_section_data (input_section)->stab_info == NULL)
		outrel.r_offset = rel->r_offset;
	      else
		{
		  bfd_vma off;

		  off = (_bfd_stab_section_offset
			 (output_bfd, &elf_hash_table (info)->stab_info,
			  input_section,
			  &elf_section_data (input_section)->stab_info,
			  rel->r_offset));
		  if (off == (bfd_vma) -1)
		    skip = true;
		  outrel.r_offset = off;
		}