elf32-arm.h

基于4个mips核的noc设计

  /* Now go back and fix up the original BL insn to point
     to here.  */
  ret_offset =
    s->output_offset
    + my_offset
    - (input_section->output_offset
       + offset + addend)
    - 8;

  tmp = bfd_get_32 (input_bfd, hit_data
		    - input_section->vma);

  bfd_put_32 (output_bfd,
	      insert_thumb_branch (tmp, ret_offset),
	      hit_data - input_section->vma);

  return true;
}

/* Arm code calling a Thumb function.  */

static int
elf32_arm_to_thumb_stub (info, name, input_bfd, output_bfd, input_section,
			 hit_data, sym_sec, offset, addend, val)
     struct bfd_link_info * info;
     const char *           name;
     bfd *                  input_bfd;
     bfd *                  output_bfd;
     asection *             input_section;
     bfd_byte *             hit_data;
     asection *             sym_sec;
     bfd_vma                offset;
     bfd_signed_vma         addend;
     bfd_vma                val;
{
  unsigned long int tmp;
  long int my_offset;
  asection * s;
  long int ret_offset;
  struct elf_link_hash_entry * myh;
  struct elf32_arm_link_hash_table * globals;

  myh = find_arm_glue (info, name, input_bfd);
  if (myh == NULL)
    return false;

  globals = elf32_arm_hash_table (info);

  BFD_ASSERT (globals != NULL);
  BFD_ASSERT (globals->bfd_of_glue_owner != NULL);

  my_offset = myh->root.u.def.value;
  s = bfd_get_section_by_name (globals->bfd_of_glue_owner,
			       ARM2THUMB_GLUE_SECTION_NAME);
  BFD_ASSERT (s != NULL);
  BFD_ASSERT (s->contents != NULL);
  BFD_ASSERT (s->output_section != NULL);

  if ((my_offset & 0x01) == 0x01)
    {
      if (sym_sec != NULL
	  && sym_sec->owner != NULL
	  && !INTERWORK_FLAG (sym_sec->owner))
	{
	  _bfd_error_handler
	    (_("%s(%s): warning: interworking not enabled."),
	     bfd_get_filename (sym_sec->owner), name);
	  _bfd_error_handler
	    (_("  first occurrence: %s: arm call to thumb"),
	     bfd_get_filename (input_bfd));
	}

      --my_offset;
      myh->root.u.def.value = my_offset;

      bfd_put_32 (output_bfd, a2t1_ldr_insn,
		  s->contents + my_offset);

      bfd_put_32 (output_bfd, a2t2_bx_r12_insn,
		  s->contents + my_offset + 4);

      /* It's a thumb address.  Add the low order bit.  */
      bfd_put_32 (output_bfd, val | a2t3_func_addr_insn,
		  s->contents + my_offset + 8);
    }

  BFD_ASSERT (my_offset <= globals->arm_glue_size);

  tmp = bfd_get_32 (input_bfd, hit_data);
  tmp = tmp & 0xFF000000;

  /* Somehow these are both 4 too far, so subtract 8.  */
  ret_offset = s->output_offset
    + my_offset
    + s->output_section->vma
    - (input_section->output_offset
       + input_section->output_section->vma
       + offset + addend)
    - 8;

  tmp = tmp | ((ret_offset >> 2) & 0x00FFFFFF);

  bfd_put_32 (output_bfd, tmp, hit_data
	      - input_section->vma);

  return true;
}

/* Perform a relocation as part of a final link.  */

static bfd_reloc_status_type
elf32_arm_final_link_relocate (howto, input_bfd, output_bfd,
			       input_section, contents, rel, value,
			       info, sym_sec, sym_name, sym_flags, h)
     reloc_howto_type *     howto;
     bfd *                  input_bfd;
     bfd *                  output_bfd;
     asection *             input_section;
     bfd_byte *             contents;
     Elf_Internal_Rela *    rel;
     bfd_vma                value;
     struct bfd_link_info * info;
     asection *             sym_sec;
     const char *           sym_name;
     unsigned char          sym_flags;
     struct elf_link_hash_entry * h;
{
  unsigned long                 r_type = howto->type;
  unsigned long                 r_symndx;
  bfd_byte *                    hit_data = contents + rel->r_offset;
  bfd *                         dynobj = NULL;
  Elf_Internal_Shdr *           symtab_hdr;
  struct elf_link_hash_entry ** sym_hashes;
  bfd_vma *                     local_got_offsets;
  asection *                    sgot = NULL;
  asection *                    splt = NULL;
  asection *                    sreloc = NULL;
  bfd_vma                       addend;
  bfd_signed_vma                signed_addend;
  struct elf32_arm_link_hash_table * globals;

  /* If the start address has been set, then set the EF_ARM_HASENTRY
     flag.  Setting this more than once is redundant, but the cost is
     not too high, and it keeps the code simple.
     
     The test is done  here, rather than somewhere else, because the
     start address is only set just before the final link commences.

     Note - if the user deliberately sets a start address of 0, the
     flag will not be set.  */
  if (bfd_get_start_address (output_bfd) != 0)
    elf_elfheader (output_bfd)->e_flags |= EF_ARM_HASENTRY;
      
  globals = elf32_arm_hash_table (info);

  dynobj = elf_hash_table (info)->dynobj;
  if (dynobj)
    {
      sgot = bfd_get_section_by_name (dynobj, ".got");
      splt = bfd_get_section_by_name (dynobj, ".plt");
    }
  symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (input_bfd);
  local_got_offsets = elf_local_got_offsets (input_bfd);
  r_symndx = ELF32_R_SYM (rel->r_info);

#ifdef USE_REL
  addend = bfd_get_32 (input_bfd, hit_data) & howto->src_mask;

  if (addend & ((howto->src_mask + 1) >> 1))
    {
      signed_addend = -1;
      signed_addend &= ~ howto->src_mask;
      signed_addend |= addend;
    }
  else
    signed_addend = addend;
#else
  addend = signed_addend = rel->r_addend;
#endif

  switch (r_type)
    {
    case R_ARM_NONE:
      return bfd_reloc_ok;

    case R_ARM_PC24:
    case R_ARM_ABS32:
    case R_ARM_REL32:
#ifndef OLD_ARM_ABI
    case R_ARM_XPC25:
#endif
      /* When generating a shared object, these relocations are copied
	 into the output file to be resolved at run time.  */
      if (info->shared
	  && (r_type != R_ARM_PC24
 	      || (h != NULL
	          && h->dynindx != -1
		  && (! info->symbolic
		      || (h->elf_link_hash_flags
			  & ELF_LINK_HASH_DEF_REGULAR) == 0))))
	{
	  Elf_Internal_Rel outrel;
	  boolean skip, relocate;

	  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 bfd_reloc_notsupported;

	      BFD_ASSERT (strncmp (name, ".rel", 4) == 0
			  && strcmp (bfd_get_section_name (input_bfd,
							   input_section),
				     name + 4) == 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;
	    }

	  outrel.r_offset += (input_section->output_section->vma
			      + input_section->output_offset);

	  if (skip)
	    {
	      memset (&outrel, 0, sizeof outrel);
	      relocate = false;
	    }
	  else if (r_type == R_ARM_PC24)
	    {
	      BFD_ASSERT (h != NULL && h->dynindx != -1);
	      if ((input_section->flags & SEC_ALLOC) != 0)
		relocate = false;
	      else
		relocate = true;
	      outrel.r_info = ELF32_R_INFO (h->dynindx, R_ARM_PC24);
	    }
	  else
	    {
	      if (h == NULL
		  || ((info->symbolic || h->dynindx == -1)
		      && (h->elf_link_hash_flags
			  & ELF_LINK_HASH_DEF_REGULAR) != 0))
		{
		  relocate = true;
		  outrel.r_info = ELF32_R_INFO (0, R_ARM_RELATIVE);
		}
	      else
		{
		  BFD_ASSERT (h->dynindx != -1);
		  if ((input_section->flags & SEC_ALLOC) != 0)
		    relocate = false;
		  else
		    relocate = true;
		  outrel.r_info = ELF32_R_INFO (h->dynindx, R_ARM_ABS32);
		}
	    }

	  bfd_elf32_swap_reloc_out (output_bfd, &outrel,
				    (((Elf32_External_Rel *)
				      sreloc->contents)
				     + sreloc->reloc_count));
	  ++sreloc->reloc_count;

	  /* If this reloc is against an external symbol, we do not want to
	     fiddle with the addend.  Otherwise, we need to include the symbol
	     value so that it becomes an addend for the dynamic reloc.  */
	  if (! relocate)
	    return bfd_reloc_ok;

	  return _bfd_final_link_relocate (howto, input_bfd, input_section,
					   contents, rel->r_offset, value,
					   (bfd_vma) 0);
	}
      else switch (r_type)
	{
#ifndef OLD_ARM_ABI
	case R_ARM_XPC25:	  /* Arm BLX instruction.  */
#endif
	case R_ARM_PC24:	  /* Arm B/BL instruction */
#ifndef OLD_ARM_ABI
	  if (r_type == R_ARM_XPC25)
	    {
	      /* Check for Arm calling Arm function.  */
	      /* FIXME: Should we translate the instruction into a BL
		 instruction instead ?  */
	      if (sym_flags != STT_ARM_TFUNC)
		_bfd_error_handler (_("\
%s: Warning: Arm BLX instruction targets Arm function '%s'."),
				    bfd_get_filename (input_bfd),
				    h ? h->root.root.string : "(local)");
	    }
	  else
#endif
	    {
	      /* Check for Arm calling Thumb function.  */
	      if (sym_flags == STT_ARM_TFUNC)
		{
		  elf32_arm_to_thumb_stub (info, sym_name, input_bfd, output_bfd,
					   input_section, hit_data, sym_sec, rel->r_offset,
					   signed_addend, value);
		  return bfd_reloc_ok;
		}
	    }

	  if (   strcmp (bfd_get_target (input_bfd), "elf32-littlearm-oabi") == 0
	      || strcmp (bfd_get_target (input_bfd), "elf32-bigarm-oabi") == 0)
	    {
	      /* The old way of doing things.  Trearing the addend as a
		 byte sized field and adding in the pipeline offset.  */
	      value -= (input_section->output_section->vma
			+ input_section->output_offset);
	      value -= rel->r_offset;
	      value += addend;

	      if (! globals->no_pipeline_knowledge)
		value -= 8;
	    }
	  else
	    {
	      /* The ARM ELF ABI says that this reloc is computed as: S - P + A
		 where:
		  S is the address of the symbol in the relocation.
		  P is address of the instruction being relocated.
		  A is the addend (extracted from the instruction) in bytes.

		 S is held in 'value'.
		 P is the base address of the section containing the instruction
		   plus the offset of the reloc into that section, ie:
		     (input_section->output_section->vma +
		      input_section->output_offset +
		      rel->r_offset).
		 A is the addend, converted into bytes, ie:
		     (signed_addend * 4)

		 Note: None of these operations have knowledge of the pipeline
		 size of the processor, thus it is up to the assembler to encode
		 this information into the addend.  */
	      value -= (input_section->output_section->vma
			+ input_section->output_offset);
	      value -= rel->r_offset;
	      value += (signed_addend << howto->size);

	      /* Previous versions of this code also used to add in the pipeline
		 offset here.  This is wrong because the linker is not supposed
		 to know about such things, and one day it might change.  In order
		 to support old binaries that need the old behaviour however, so
		 we attempt to detect which ABI was used to create the reloc.  */
	      if (! globals->no_pipeline_knowledge)
		{
		  Elf_Internal_Ehdr * i_ehdrp; /* Elf file header, internal form */

		  i_ehdrp = elf_elfheader (input_bfd);

		  if (i_ehdrp->e_ident[EI_OSABI] == 0)
		    value -= 8;
		}
	    }

	  signed_addend = value;
	  signed_addend >>= howto->rightshift;

	  /* It is not an error for an undefined weak reference to be
	     out of range.  Any program that branches to such a symbol
	     is going to crash anyway, so there is no point worrying
	     about getting the destination exactly right.  */
	  if (! h || h->root.type != bfd_link_hash_undefweak)
	    {
	      /* Perform a signed range check.  */
	      if (   signed_addend >   ((bfd_signed_vma)  (howto->dst_mask >> 1))
		  || signed_addend < - ((bfd_signed_vma) ((howto->dst_mask + 1) >> 1)))
		return bfd_reloc_overflow;
	    }

#ifndef OLD_ARM_ABI
	  /* If necessary set the H bit in the BLX instruction.  */
	  if (r_type == R_ARM_XPC25 && ((value & 2) == 2))
	    value = (signed_addend & howto->dst_mask)
	      | (bfd_get_32 (input_bfd, hit_data) & (~ howto->dst_mask))
	      | (1 << 24);
	  else
#endif
	    value = (signed_addend & howto->dst_mask)
	      | (bfd_get_32 (input_bfd, hit_data) & (~ howto->dst_mask));
	  break;

	case R_ARM_ABS32:
	  value += addend;
	  if (sym_flags == STT_ARM_TFUNC)
	    value |= 1;
	  break;

	case R_ARM_REL32:
	  value -= (input_section->output_section->vma
		    + input_section->output_offset);
	  value += addend;
	  break;
	}

      bfd_put_32 (input_bfd, value, hit_data);
      return bfd_reloc_ok;

    case R_ARM_ABS8:
      value += addend;
      if ((long) value > 0x7f || (long) value < -0x80)
	return bfd_reloc_overflow;

      bfd_put_8 (input_bfd, value, hit_data);
      return bfd_reloc_ok;

    case R_ARM_ABS16:
      value += addend;

      if ((long) value > 0x7fff || (long) value < -0x8000)
	return bfd_reloc_overflow;

      bfd_put_16 (input_bfd, value, hit_data);