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

  fputc ('\n', file);

  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.  */

static boolean
elf_m68k_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;
  bfd_signed_vma *local_got_refcounts;
  const Elf_Internal_Rela *rel;
  const Elf_Internal_Rela *rel_end;
  asection *sgot;
  asection *srelgot;
  asection *sreloc;

  if (info->relocateable)
    return true;

  dynobj = elf_hash_table (info)->dynobj;
  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);
  local_got_refcounts = elf_local_got_refcounts (abfd);

  sgot = NULL;
  srelgot = NULL;
  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];

      switch (ELF32_R_TYPE (rel->r_info))
	{
	case R_68K_GOT8:
	case R_68K_GOT16:
	case R_68K_GOT32:
	  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:
	  /* This symbol requires a global offset table entry.  */

	  if (dynobj == NULL)
	    {
	      /* Create the .got section.  */
	      elf_hash_table (info)->dynobj = dynobj = abfd;
	      if (!_bfd_elf_create_got_section (dynobj, info))
		return false;
	    }

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

	  if (srelgot == NULL
	      && (h != NULL || info->shared))
	    {
	      srelgot = bfd_get_section_by_name (dynobj, ".rela.got");
	      if (srelgot == NULL)
		{
		  srelgot = bfd_make_section (dynobj, ".rela.got");
		  if (srelgot == NULL
		      || !bfd_set_section_flags (dynobj, srelgot,
						 (SEC_ALLOC
						  | SEC_LOAD
						  | SEC_HAS_CONTENTS
						  | SEC_IN_MEMORY
						  | SEC_LINKER_CREATED
						  | SEC_READONLY))
		      || !bfd_set_section_alignment (dynobj, srelgot, 2))
		    return false;
		}
	    }

	  if (h != NULL)
	    {
	      if (h->got.refcount == -1)
		{
		  h->got.refcount = 1;

		  /* Make sure this symbol is output as a dynamic symbol.  */
		  if (h->dynindx == -1)
		    {
		      if (!bfd_elf32_link_record_dynamic_symbol (info, h))
			return false;
		    }

		  /* Allocate space in the .got section.  */
		  sgot->_raw_size += 4;
		  /* Allocate relocation space.  */
		  srelgot->_raw_size += sizeof (Elf32_External_Rela);
		}
	      else
		h->got.refcount++;
	    }
	  else
	    {
	      /* This is a global offset table entry for a local symbol.  */
	      if (local_got_refcounts == NULL)
		{
		  size_t size;

		  size = symtab_hdr->sh_info * sizeof (bfd_signed_vma);
		  local_got_refcounts = ((bfd_signed_vma *)
					 bfd_alloc (abfd, size));
		  if (local_got_refcounts == NULL)
		    return false;
		  elf_local_got_refcounts (abfd) = local_got_refcounts;
		  memset (local_got_refcounts, -1, size);
		}
	      if (local_got_refcounts[r_symndx] == -1)
		{
		  local_got_refcounts[r_symndx] = 1;

		  sgot->_raw_size += 4;
		  if (info->shared)
		    {
		      /* If we are generating a shared object, we need to
			 output a R_68K_RELATIVE reloc so that the dynamic
			 linker can adjust this GOT entry.  */
		      srelgot->_raw_size += sizeof (Elf32_External_Rela);
		    }
		}
	      else
		local_got_refcounts[r_symndx]++;
	    }
	  break;

	case R_68K_PLT8:
	case R_68K_PLT16:
	case R_68K_PLT32:
	  /* This symbol requires a procedure linkage table entry.  We
	     actually build the entry in adjust_dynamic_symbol,
             because this might be a case of linking PIC code which is
             never referenced by a dynamic object, in which case we
             don't need to generate a procedure linkage table entry
             after all.  */

	  /* If this is a local symbol, we resolve it directly without
	     creating a procedure linkage table entry.  */
	  if (h == NULL)
	    continue;

	  h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
	  if (h->plt.refcount == -1)
	    h->plt.refcount = 1;
	  else
	    h->plt.refcount++;
	  break;

	case R_68K_PLT8O:
	case R_68K_PLT16O:
	case R_68K_PLT32O:
	  /* This symbol requires a procedure linkage table entry.  */

	  if (h == NULL)
	    {
	      /* It does not make sense to have this relocation for a
		 local symbol.  FIXME: does it?  How to handle it if
		 it does make sense?  */
	      bfd_set_error (bfd_error_bad_value);
	      return false;
	    }

	  /* Make sure this symbol is output as a dynamic symbol.  */
	  if (h->dynindx == -1)
	    {
	      if (!bfd_elf32_link_record_dynamic_symbol (info, h))
		return false;
	    }

	  h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
	  if (h->plt.refcount == -1)
	    h->plt.refcount = 1;
	  else
	    h->plt.refcount++;
	  break;

	case R_68K_PC8:
	case R_68K_PC16:
	case R_68K_PC32:
	  /* If we are creating a shared library and this is not a local
	     symbol, we need to copy the reloc into the shared library.
	     However when linking with -Bsymbolic and this is a global
	     symbol which is defined in an object we are including in the
	     link (i.e., DEF_REGULAR is set), then we can resolve the
	     reloc directly.  At this point we have not seen all the input
	     files, so it is possible that DEF_REGULAR is not set now but
	     will be set later (it is never cleared).  We account for that
	     possibility below by storing information in the
	     pcrel_relocs_copied field of the hash table entry.  */
	  if (!(info->shared
		&& (sec->flags & SEC_ALLOC) != 0
		&& h != NULL
		&& (!info->symbolic
		    || (h->elf_link_hash_flags
			& ELF_LINK_HASH_DEF_REGULAR) == 0)))
	    {
	      if (h != NULL)
		{
		  /* Make sure a plt entry is created for this symbol if
		     it turns out to be a function defined by a dynamic
		     object.  */
		  if (h->plt.refcount == -1)
		    h->plt.refcount = 1;
		  else
		    h->plt.refcount++;
		}
	      break;
	    }
	  /* Fall through.  */
	case R_68K_8:
	case R_68K_16:
	case R_68K_32:
	  if (h != NULL)
	    {
	      /* Make sure a plt entry is created for this symbol if it
		 turns out to be a function defined by a dynamic object.  */
	      if (h->plt.refcount == -1)
		h->plt.refcount = 1;
	      else
		h->plt.refcount++;
	    }

	  /* If we are creating a shared library, we need to copy the
	     reloc into the shared library.  */
	  if (info->shared
	      && (sec->flags & SEC_ALLOC) != 0)
	    {
	      /* When creating a shared object, we must copy these
		 reloc types into the output file.  We create a reloc
		 section in dynobj and make room for this reloc.  */
	      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)
		    {
		      sreloc = bfd_make_section (dynobj, name);
		      if (sreloc == NULL
			  || !bfd_set_section_flags (dynobj, sreloc,
						     (SEC_ALLOC
						      | SEC_LOAD
						      | SEC_HAS_CONTENTS
						      | SEC_IN_MEMORY
						      | SEC_LINKER_CREATED
						      | SEC_READONLY))
			  || !bfd_set_section_alignment (dynobj, sreloc, 2))
			return false;
		    }
		}

	      sreloc->_raw_size += sizeof (Elf32_External_Rela);

	      /* If we are linking with -Bsymbolic, we count the number of
		 PC relative relocations we have entered for this symbol,
		 so that we can discard them again if the symbol is later
		 defined by a regular object.  Note that this function is
		 only called if we are using an m68kelf linker hash table,
		 which means that h is really a pointer to an
		 elf_m68k_link_hash_entry.  */
	      if ((ELF32_R_TYPE (rel->r_info) == R_68K_PC8
 		   || ELF32_R_TYPE (rel->r_info) == R_68K_PC16
 		   || ELF32_R_TYPE (rel->r_info) == R_68K_PC32)
		  && info->symbolic)
		{
		  struct elf_m68k_link_hash_entry *eh;
		  struct elf_m68k_pcrel_relocs_copied *p;

		  eh = (struct elf_m68k_link_hash_entry *) h;

		  for (p = eh->pcrel_relocs_copied; p != NULL; p = p->next)
		    if (p->section == sreloc)
		      break;

		  if (p == NULL)
		    {
		      p = ((struct elf_m68k_pcrel_relocs_copied *)
			   bfd_alloc (dynobj, sizeof *p));
		      if (p == NULL)
			return false;
		      p->next = eh->pcrel_relocs_copied;
		      eh->pcrel_relocs_copied = p;
		      p->section = sreloc;
		      p->count = 0;
		    }

		  ++p->count;
		}
	    }

	  break;

	  /* This relocation describes the C++ object vtable hierarchy.
	     Reconstruct it for later use during GC.  */
	case R_68K_GNU_VTINHERIT:
	  if (!_bfd_elf32_gc_record_vtinherit (abfd, sec, h, rel->r_offset))
	    return false;
	  break;

	  /* This relocation describes which C++ vtable entries are actually
	     used.  Record for later use during GC.  */
	case R_68K_GNU_VTENTRY:
	  if (!_bfd_elf32_gc_record_vtentry (abfd, sec, h, rel->r_addend))
	    return false;
	  break;

	default:
	  break;
	}
    }

  return true;
}

/* Return the section that should be marked against GC for a given
   relocation.  */

static asection *
elf_m68k_gc_mark_hook (abfd, info, rel, h, sym)
     bfd *abfd;
     struct bfd_link_info *info ATTRIBUTE_UNUSED;
     Elf_Internal_Rela *rel;
     struct elf_link_hash_entry *h;
     Elf_Internal_Sym *sym;
{
  if (h != NULL)
    {
      switch (ELF32_R_TYPE (rel->r_info))
	{
	case R_68K_GNU_VTINHERIT:
	case R_68K_GNU_VTENTRY:
	  break;

	default:
	  switch (h->root.type)
	    {
	    default:
	      break;

	    case bfd_link_hash_defined:
	    case bfd_link_hash_defweak:
	      return h->root.u.def.section;

	    case bfd_link_hash_common:
	      return h->root.u.c.p->section;
	    }
	}
    }
  else
    {
      if (!(elf_bad_symtab (abfd)
	    && ELF_ST_BIND (sym->st_info) != STB_LOCAL)
	  && ! ((sym->st_shndx <= 0 || sym->st_shndx >= SHN_LORESERVE)
		&& sym->st_shndx != SHN_COMMON))
	{
	  return bfd_section_from_elf_index (abfd, sym->st_shndx);
	}
    }

  return NULL;
}

/* Update the got entry reference counts for the section being removed.  */

static boolean
elf_m68k_gc_sweep_hook (abfd, info, sec, relocs)
     bfd *abfd;
     struct bfd_link_info *info;
     asection *sec;
     const Elf_Internal_Rela *relocs;
{
  Elf_Internal_Shdr *symtab_hdr;
  struct elf_link_hash_entry **sym_hashes;
  bfd_signed_vma *local_got_refcounts;
  const Elf_Internal_Rela *rel, *relend;
  unsigned long r_symndx;
  struct elf_link_hash_entry *h;
  bfd *dynobj;
  asection *sgot;
  asection *srelgot;

  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);
  local_got_refcounts = elf_local_got_refcounts (abfd);

  dynobj = elf_hash_table (info)->dynobj;
  if (dynobj == NULL)
    return true;

  sgot = bfd_get_section_by_name (dynobj, ".got");
  srelgot = bfd_get_section_by_name (dynobj, ".rela.got");

  relend = relocs + sec->reloc_count;
  for (rel = relocs; rel < relend; rel++)
    {