elf32-mcore.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 750 行 · 第 1/2 页

   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
mcore_elf_relocate_section (output_bfd, info, input_bfd, input_section,
			  contents, relocs, local_syms, local_sections)
     bfd * output_bfd ATTRIBUTE_UNUSED;
     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);
  Elf_Internal_Rela *           rel = relocs;
  Elf_Internal_Rela *           relend = relocs + input_section->reloc_count;
  boolean ret = true;

#ifdef DEBUG
  fprintf (stderr,
	   "mcore_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 (! mcore_elf_howto_table [R_MCORE_PCRELIMM8BY4])	/* Initialize howto table if needed */
    mcore_elf_howto_init ();

  for (; rel < relend; rel++)
    {
      enum elf_mcore_reloc_type    r_type = (enum elf_mcore_reloc_type) ELF32_R_TYPE (rel->r_info);
      bfd_vma                      offset = rel->r_offset;
      bfd_vma                      addend = rel->r_addend;
      bfd_reloc_status_type        r = bfd_reloc_other;
      asection *                   sec = (asection *) 0;
      reloc_howto_type *           howto;
      bfd_vma                      relocation;
      Elf_Internal_Sym *           sym = (Elf_Internal_Sym *) 0;
      unsigned long                r_symndx;
      struct elf_link_hash_entry * h = (struct elf_link_hash_entry *) 0;
      unsigned short               oldinst = 0;

      /* Unknown relocation handling */
      if ((unsigned) r_type >= (unsigned) R_MCORE_max
	  || ! mcore_elf_howto_table [(int)r_type])
	{
	  _bfd_error_handler (_("%s: Unknown relocation type %d\n"),
			      bfd_get_filename (input_bfd),
			      (int) r_type);

	  bfd_set_error (bfd_error_bad_value);
	  ret = false;
	  continue;
	}

      howto = mcore_elf_howto_table [(int) 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 ((unsigned)ELF_ST_TYPE (sym->st_info) == STT_SECTION)
		{
		  sec = local_sections[r_symndx];
		  addend = rel->r_addend += sec->output_offset + sym->st_value;
		}
	    }

#ifdef DEBUG
	  fprintf (stderr, "\ttype = %s (%d), symbol index = %ld, offset = %ld, addend = %ld\n",
		   howto->name, (int) r_type, r_symndx, (long) offset, (long) addend);
#endif
	  continue;
	}

      /* This is a final link.  */

      /* Complain about known relocation that are not yet supported.  */
      if (howto->special_function == mcore_elf_unsupported_reloc)
	{
	  _bfd_error_handler (_("%s: Relocation %s (%d) is not currently supported.\n"),
			      bfd_get_filename (input_bfd),
			      howto->name,
			      (int)r_type);

	  bfd_set_error (bfd_error_bad_value);
	  ret = false;
	  continue;
	}

      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];
	  if (   h->root.type == bfd_link_hash_defined
	      || h->root.type == bfd_link_hash_defweak)
	    {
	      sec = h->root.u.def.section;
	      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
		   && 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, true)))
		return false;

	      ret = false;
	      continue;
	    }
	}

      switch (r_type)
	{
	default:
	  break;

	case R_MCORE_PCRELJSR_IMM11BY2:
	  oldinst = bfd_get_16 (input_bfd, contents + offset);
#define	MCORE_INST_BSR	0xF800
	  bfd_put_16 (input_bfd, MCORE_INST_BSR, contents + offset);
	  break;
	}

#ifdef DEBUG
      fprintf (stderr, "\ttype = %s (%d), symbol index = %ld, offset = %ld, addend = %ld\n",
	       howto->name, r_type, r_symndx, (long) offset, (long) addend);
#endif

      r = _bfd_final_link_relocate
	(howto, input_bfd, input_section, contents, offset, relocation, addend);

      if (r != bfd_reloc_ok && r_type == R_MCORE_PCRELJSR_IMM11BY2)
	{
	  /* Wasn't ok, back it out and give up.  */
	  bfd_put_16 (input_bfd, oldinst, contents + offset);
	  r = bfd_reloc_ok;
	}

      if (r != bfd_reloc_ok)
	{
	  ret = false;

	  switch (r)
	    {
	    default:
	      break;

	    case bfd_reloc_overflow:
	      {
		const char * name;

		if (h != NULL)
		  name = h->root.root.string;
		else
		  {
		    name = bfd_elf_string_from_elf_section
		      (input_bfd, symtab_hdr->sh_link, sym->st_name);

		    if (name == NULL)
		      break;

		    if (* name == '\0')
		      name = bfd_section_name (input_bfd, sec);
		  }

		(*info->callbacks->reloc_overflow)
		  (info, name, howto->name, (bfd_vma) 0, input_bfd, input_section,
		   offset);
	      }
	      break;
	    }
	}
    }

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

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

static asection *
mcore_elf_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_MCORE_GNU_VTINHERIT:
	case R_MCORE_GNU_VTENTRY:
	  break;

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

	    default:
	      break;
	    }
	}
    }
  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
mcore_elf_gc_sweep_hook (abfd, info, sec, relocs)
     bfd *                     abfd ATTRIBUTE_UNUSED;
     struct bfd_link_info *    info ATTRIBUTE_UNUSED;
     asection *                sec ATTRIBUTE_UNUSED;
     const Elf_Internal_Rela * relocs ATTRIBUTE_UNUSED;
{
  return true;
}

/* Look through the relocs for a section during the first phase.
   Since we don't do .gots or .plts, we just need to consider the
   virtual table relocs for gc.  */

static boolean
mcore_elf_check_relocs (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;
  struct elf_link_hash_entry ** sym_hashes_end;
  const Elf_Internal_Rela *     rel;
  const Elf_Internal_Rela *     rel_end;

  if (info->relocateable)
    return true;

  symtab_hdr = & elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);
  sym_hashes_end = sym_hashes + symtab_hdr->sh_size / sizeof (Elf32_External_Sym);
  if (!elf_bad_symtab (abfd))
    sym_hashes_end -= symtab_hdr->sh_info;

  rel_end = relocs + sec->reloc_count;

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

      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))
        {
        /* This relocation describes the C++ object vtable hierarchy.
           Reconstruct it for later use during GC.  */
        case R_MCORE_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_MCORE_GNU_VTENTRY:
          if (!_bfd_elf32_gc_record_vtentry (abfd, sec, h, rel->r_addend))
            return false;
          break;
        }
    }

  return true;
}

#define TARGET_BIG_SYM		bfd_elf32_mcore_big_vec
#define TARGET_BIG_NAME		"elf32-mcore-big"
#define TARGET_LITTLE_SYM       bfd_elf32_mcore_little_vec
#define TARGET_LITTLE_NAME      "elf32-mcore-little"

#define ELF_ARCH		bfd_arch_mcore
#define ELF_MACHINE_CODE	EM_MCORE
#define ELF_MAXPAGESIZE		0x1000		/* 4k, if we ever have 'em */
#define elf_info_to_howto	mcore_elf_info_to_howto
#define elf_info_to_howto_rel	NULL

#define bfd_elf32_bfd_copy_private_bfd_data	mcore_elf_copy_private_bfd_data
#define bfd_elf32_bfd_merge_private_bfd_data	mcore_elf_merge_private_bfd_data
#define bfd_elf32_bfd_set_private_flags		mcore_elf_set_private_flags
#define bfd_elf32_bfd_reloc_type_lookup		mcore_elf_reloc_type_lookup
#define elf_backend_relocate_section		mcore_elf_relocate_section
#define elf_backend_gc_mark_hook		mcore_elf_gc_mark_hook
#define elf_backend_gc_sweep_hook		mcore_elf_gc_sweep_hook
#define elf_backend_check_relocs                mcore_elf_check_relocs

#define elf_backend_can_gc_sections		1

#include "elf32-target.h"