coff-alpha.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 2,226 行 · 第 1/5 页

      /* Alpha ECOFF has a .pdata section.  The lnnoptr field of the
	 .pdata section is the number of entries it contains.  Each
	 entry takes up 8 bytes.  The number of entries is required
	 since the section is aligned to a 16 byte boundary.  When we
	 link .pdata sections together, we do not want to include the
	 alignment bytes.  We handle this on input by faking the size
	 of the .pdata section to remove the unwanted alignment bytes.
	 On output we will set the lnnoptr field and force the
	 alignment.  */
      sec = bfd_get_section_by_name (abfd, _PDATA);
      if (sec != (asection *) NULL)
	{
	  bfd_size_type size;

	  size = sec->line_filepos * 8;
	  BFD_ASSERT (size == bfd_section_size (abfd, sec)
		      || size + 8 == bfd_section_size (abfd, sec));
	  if (! bfd_set_section_size (abfd, sec, size))
	    return NULL;
	}
    }

  return ret;
}

/* See whether the magic number matches.  */

static boolean
alpha_ecoff_bad_format_hook (abfd, filehdr)
     bfd *abfd ATTRIBUTE_UNUSED;
     PTR filehdr;
{
  struct internal_filehdr *internal_f = (struct internal_filehdr *) filehdr;

  if (ALPHA_ECOFF_BADMAG (*internal_f))
    return false;

  return true;
}

/* This is a hook called by coff_real_object_p to create any backend
   specific information.  */

static PTR
alpha_ecoff_mkobject_hook (abfd, filehdr, aouthdr)
     bfd *abfd;
     PTR filehdr;
     PTR aouthdr;
{
  PTR ecoff;

  ecoff = _bfd_ecoff_mkobject_hook (abfd, filehdr, aouthdr);

  if (ecoff != NULL)
    {
      struct internal_filehdr *internal_f = (struct internal_filehdr *) filehdr;

      /* Set additional BFD flags according to the object type from the
	 machine specific file header flags.  */
      switch (internal_f->f_flags & F_ALPHA_OBJECT_TYPE_MASK)
	{
	case F_ALPHA_SHARABLE:
	  abfd->flags |= DYNAMIC;
	  break;
	case F_ALPHA_CALL_SHARED:
	  /* Always executable if using shared libraries as the run time
	     loader might resolve undefined references.  */
	  abfd->flags |= (DYNAMIC | EXEC_P);
	  break;
	}
    }
  return ecoff;
}

/* Reloc handling.  */

/* Swap a reloc in.  */

static void
alpha_ecoff_swap_reloc_in (abfd, ext_ptr, intern)
     bfd *abfd;
     PTR ext_ptr;
     struct internal_reloc *intern;
{
  const RELOC *ext = (RELOC *) ext_ptr;

  intern->r_vaddr = bfd_h_get_64 (abfd, (bfd_byte *) ext->r_vaddr);
  intern->r_symndx = bfd_h_get_32 (abfd, (bfd_byte *) ext->r_symndx);

  BFD_ASSERT (bfd_header_little_endian (abfd));

  intern->r_type = ((ext->r_bits[0] & RELOC_BITS0_TYPE_LITTLE)
		    >> RELOC_BITS0_TYPE_SH_LITTLE);
  intern->r_extern = (ext->r_bits[1] & RELOC_BITS1_EXTERN_LITTLE) != 0;
  intern->r_offset = ((ext->r_bits[1] & RELOC_BITS1_OFFSET_LITTLE)
		      >> RELOC_BITS1_OFFSET_SH_LITTLE);
  /* Ignored the reserved bits.  */
  intern->r_size = ((ext->r_bits[3] & RELOC_BITS3_SIZE_LITTLE)
		    >> RELOC_BITS3_SIZE_SH_LITTLE);

  if (intern->r_type == ALPHA_R_LITUSE
      || intern->r_type == ALPHA_R_GPDISP)
    {
      /* Handle the LITUSE and GPDISP relocs specially.  Its symndx
	 value is not actually a symbol index, but is instead a
	 special code.  We put the code in the r_size field, and
	 clobber the symndx.  */
      if (intern->r_size != 0)
	abort ();
      intern->r_size = intern->r_symndx;
      intern->r_symndx = RELOC_SECTION_NONE;
    }
  else if (intern->r_type == ALPHA_R_IGNORE)
    {
      /* The IGNORE reloc generally follows a GPDISP reloc, and is
	 against the .lita section.  The section is irrelevant.  */
      if (! intern->r_extern &&
	  intern->r_symndx == RELOC_SECTION_ABS)
	abort ();
      if (! intern->r_extern && intern->r_symndx == RELOC_SECTION_LITA)
	intern->r_symndx = RELOC_SECTION_ABS;
    }
}

/* Swap a reloc out.  */

static void
alpha_ecoff_swap_reloc_out (abfd, intern, dst)
     bfd *abfd;
     const struct internal_reloc *intern;
     PTR dst;
{
  RELOC *ext = (RELOC *) dst;
  long symndx;
  unsigned char size;

  /* Undo the hackery done in swap_reloc_in.  */
  if (intern->r_type == ALPHA_R_LITUSE
      || intern->r_type == ALPHA_R_GPDISP)
    {
      symndx = intern->r_size;
      size = 0;
    }
  else if (intern->r_type == ALPHA_R_IGNORE
	   && ! intern->r_extern
	   && intern->r_symndx == RELOC_SECTION_ABS)
    {
      symndx = RELOC_SECTION_LITA;
      size = intern->r_size;
    }
  else
    {
      symndx = intern->r_symndx;
      size = intern->r_size;
    }

  BFD_ASSERT (intern->r_extern
	      || (intern->r_symndx >= 0 && intern->r_symndx <= 14));

  bfd_h_put_64 (abfd, intern->r_vaddr, (bfd_byte *) ext->r_vaddr);
  bfd_h_put_32 (abfd, symndx, (bfd_byte *) ext->r_symndx);

  BFD_ASSERT (bfd_header_little_endian (abfd));

  ext->r_bits[0] = ((intern->r_type << RELOC_BITS0_TYPE_SH_LITTLE)
		    & RELOC_BITS0_TYPE_LITTLE);
  ext->r_bits[1] = ((intern->r_extern ? RELOC_BITS1_EXTERN_LITTLE : 0)
		    | ((intern->r_offset << RELOC_BITS1_OFFSET_SH_LITTLE)
		       & RELOC_BITS1_OFFSET_LITTLE));
  ext->r_bits[2] = 0;
  ext->r_bits[3] = ((size << RELOC_BITS3_SIZE_SH_LITTLE)
		    & RELOC_BITS3_SIZE_LITTLE);
}

/* Finish canonicalizing a reloc.  Part of this is generic to all
   ECOFF targets, and that part is in ecoff.c.  The rest is done in
   this backend routine.  It must fill in the howto field.  */

static void
alpha_adjust_reloc_in (abfd, intern, rptr)
     bfd *abfd;
     const struct internal_reloc *intern;
     arelent *rptr;
{
  if (intern->r_type > ALPHA_R_GPVALUE)
    abort ();

  switch (intern->r_type)
    {
    case ALPHA_R_BRADDR:
    case ALPHA_R_SREL16:
    case ALPHA_R_SREL32:
    case ALPHA_R_SREL64:
      /* This relocs appear to be fully resolved when they are against
         internal symbols.  Against external symbols, BRADDR at least
         appears to be resolved against the next instruction.  */
      if (! intern->r_extern)
	rptr->addend = 0;
      else
	rptr->addend = - (intern->r_vaddr + 4);
      break;

    case ALPHA_R_GPREL32:
    case ALPHA_R_LITERAL:
      /* Copy the gp value for this object file into the addend, to
	 ensure that we are not confused by the linker.  */
      if (! intern->r_extern)
	rptr->addend += ecoff_data (abfd)->gp;
      break;

    case ALPHA_R_LITUSE:
    case ALPHA_R_GPDISP:
      /* The LITUSE and GPDISP relocs do not use a symbol, or an
	 addend, but they do use a special code.  Put this code in the
	 addend field.  */
      rptr->addend = intern->r_size;
      break;

    case ALPHA_R_OP_STORE:
      /* The STORE reloc needs the size and offset fields.  We store
	 them in the addend.  */
      BFD_ASSERT (intern->r_offset <= 256 && intern->r_size <= 256);
      rptr->addend = (intern->r_offset << 8) + intern->r_size;
      break;

    case ALPHA_R_OP_PUSH:
    case ALPHA_R_OP_PSUB:
    case ALPHA_R_OP_PRSHIFT:
      /* The PUSH, PSUB and PRSHIFT relocs do not actually use an
	 address.  I believe that the address supplied is really an
	 addend.  */
      rptr->addend = intern->r_vaddr;
      break;

    case ALPHA_R_GPVALUE:
      /* Set the addend field to the new GP value.  */
      rptr->addend = intern->r_symndx + ecoff_data (abfd)->gp;
      break;

    case ALPHA_R_IGNORE:
      /* If the type is ALPHA_R_IGNORE, make sure this is a reference
	 to the absolute section so that the reloc is ignored.  For
	 some reason the address of this reloc type is not adjusted by
	 the section vma.  We record the gp value for this object file
	 here, for convenience when doing the GPDISP relocation.  */
      rptr->sym_ptr_ptr = bfd_abs_section_ptr->symbol_ptr_ptr;
      rptr->address = intern->r_vaddr;
      rptr->addend = ecoff_data (abfd)->gp;
      break;

    default:
      break;
    }

  rptr->howto = &alpha_howto_table[intern->r_type];
}

/* When writing out a reloc we need to pull some values back out of
   the addend field into the reloc.  This is roughly the reverse of
   alpha_adjust_reloc_in, except that there are several changes we do
   not need to undo.  */

static void
alpha_adjust_reloc_out (abfd, rel, intern)
     bfd *abfd ATTRIBUTE_UNUSED;
     const arelent *rel;
     struct internal_reloc *intern;
{
  switch (intern->r_type)
    {
    case ALPHA_R_LITUSE:
    case ALPHA_R_GPDISP:
      intern->r_size = rel->addend;
      break;

    case ALPHA_R_OP_STORE:
      intern->r_size = rel->addend & 0xff;
      intern->r_offset = (rel->addend >> 8) & 0xff;
      break;

    case ALPHA_R_OP_PUSH:
    case ALPHA_R_OP_PSUB:
    case ALPHA_R_OP_PRSHIFT:
      intern->r_vaddr = rel->addend;
      break;

    case ALPHA_R_IGNORE:
      intern->r_vaddr = rel->address;
      break;

    default:
      break;
    }
}

/* The size of the stack for the relocation evaluator.  */
#define RELOC_STACKSIZE (10)

/* Alpha ECOFF relocs have a built in expression evaluator as well as
   other interdependencies.  Rather than use a bunch of special
   functions and global variables, we use a single routine to do all
   the relocation for a section.  I haven't yet worked out how the
   assembler is going to handle this.  */

static bfd_byte *
alpha_ecoff_get_relocated_section_contents (abfd, link_info, link_order,
					    data, relocateable, symbols)
     bfd *abfd;
     struct bfd_link_info *link_info;
     struct bfd_link_order *link_order;
     bfd_byte *data;
     boolean relocateable;
     asymbol **symbols;
{
  bfd *input_bfd = link_order->u.indirect.section->owner;
  asection *input_section = link_order->u.indirect.section;
  long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
  arelent **reloc_vector = NULL;
  long reloc_count;
  bfd *output_bfd = relocateable ? abfd : (bfd *) NULL;
  bfd_vma gp;
  boolean gp_undefined;
  bfd_vma stack[RELOC_STACKSIZE];
  int tos = 0;

  if (reloc_size < 0)
    goto error_return;
  reloc_vector = (arelent **) bfd_malloc (reloc_size);
  if (reloc_vector == NULL && reloc_size != 0)
    goto error_return;

  if (! bfd_get_section_contents (input_bfd, input_section, data,
				  (file_ptr) 0, input_section->_raw_size))
    goto error_return;

  /* The section size is not going to change.  */
  input_section->_cooked_size = input_section->_raw_size;
  input_section->reloc_done = true;

  reloc_count = bfd_canonicalize_reloc (input_bfd, input_section,
					reloc_vector, symbols);
  if (reloc_count < 0)
    goto error_return;
  if (reloc_count == 0)
    goto successful_return;

  /* Get the GP value for the output BFD.  */
  gp_undefined = false;
  gp = _bfd_get_gp_value (abfd);
  if (gp == 0)
    {
      if (relocateable != false)
	{
	  asection *sec;
	  bfd_vma lo;

	  /* Make up a value.  */
	  lo = (bfd_vma) -1;
	  for (sec = abfd->sections; sec != NULL; sec = sec->next)
	    {
	      if (sec->vma < lo
		  && (strcmp (sec->name, ".sbss") == 0
		      || strcmp (sec->name, ".sdata") == 0
		      || strcmp (sec->name, ".lit4") == 0
		      || strcmp (sec->name, ".lit8") == 0
		      || strcmp (sec->name, ".lita") == 0))
		lo = sec->vma;
	    }
	  gp = lo + 0x8000;
	  _bfd_set_gp_value (abfd, gp);
	}
      else
	{
	  struct bfd_link_hash_entry *h;

	  h = bfd_link_hash_lookup (link_info->hash, "_gp", false, false,
				    true);
	  if (h == (struct bfd_link_hash_entry *) NULL
	      || h->type != bfd_link_hash_defined)
	    gp_undefined = true;
	  else
	    {
	      gp = (h->u.def.value
		    + h->u.def.section->output_section->vma
		    + h->u.def.section->output_offset);
	      _bfd_set_gp_value (abfd, gp);
	    }
	}
    }

  for (; *reloc_vector != (arelent *) NULL; reloc_vector++)
    {
      arelent *rel;
      bfd_reloc_status_type r;
      char *err;

      rel = *reloc_vector;
      r = bfd_reloc_ok;
      switch (rel->howto->type)
	{
	case ALPHA_R_IGNORE:
	  rel->address += input_section->output_offset;
	  break;

	case ALPHA_R_REFLONG:
	case ALPHA_R_REFQUAD:
	case ALPHA_R_BRADDR:
	case ALPHA_R_HINT:
	case ALPHA_R_SREL16:
	case ALPHA_R_SREL32:
	case ALPHA_R_SREL64:
	  if (relocateable
	      && ((*rel->sym_ptr_ptr)->flags & BSF_SECTION_SYM) == 0)
	    {
	      rel->address += input_section->output_offset;
	      break;
	    }
	  r = bfd_perform_relocation (input_bfd, rel, data, input_section,
				      output_bfd, &err);
	  break;

	case ALPHA_R_GPREL32:
	  /* This relocation is used in a switch table.  It is a 32
	     bit offset from the current GP value.  We must adjust it
	     by the different between the original GP value and the
	     current GP value.  The original GP value is stored in the
	     addend.  We adjust the addend and let
	     bfd_perform_relocation finish the job.  */
	  rel->addend -= gp;
	  r = bfd_perform_relocation (input_bfd, rel, data, input_section,
				      output_bfd, &err);
	  if (r == bfd_reloc_ok && gp_undefined)
	    {
	      r = bfd_reloc_dangerous;
	      err = (char *) _("GP relative relocation used when GP not defined");
	    }
	  break;

	case ALPHA_R_LITERAL:
	  /* This is a reference to a literal value, generally
	     (always?) in the .lita section.  This is a 16 bit GP
	     relative relocation.  Sometimes the subsequent reloc is a
	     LITUSE reloc, which indicates how this reloc is used.
	     This sometimes permits rewriting the two instructions
	     referred to by the LITERAL and the LITUSE into different
	     instructions which do not refer to .lita.  This can save