Add PC-relative branch instructions to moxie port.

[deliverable/binutils-gdb.git] / bfd / elf32-moxie.c

/* moxie-specific support for 32-bit ELF.
   Copyright 2009 Free Software Foundation, Inc.

   Copied from elf32-fr30.c which is..
   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
   Free Software Foundation, Inc.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf/moxie.h"

/* Forward declarations.  */

static reloc_howto_type moxie_elf_howto_table [] =
{
  /* This reloc does nothing.  */
  HOWTO (R_MOXIE_NONE,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_MOXIE_NONE",		/* name */
	 FALSE,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 32 bit absolute relocation.  */
  HOWTO (R_MOXIE_32,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_MOXIE_32",		/* name */
	 FALSE,			/* partial_inplace */
	 0x00000000,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 10 bit PC-relative relocation.  */
  HOWTO (R_MOXIE_PCREL10,	/* type.  */
	 1,			/* rightshift.  */
	 1,			/* size (0 = byte, 1 = short, 2 = long).  */
	 10,			/* bitsize.  */
	 TRUE,			/* pc_relative.  */
	 0,			/* bitpos.  */
	 complain_overflow_signed, /* complain_on_overflow.  */
	 bfd_elf_generic_reloc,	/* special_function.  */
	 "R_MOXIE_PCREL10",		/* name.  */
	 FALSE,			/* partial_inplace.  */
	 0,			/* src_mask.  */
	 0x000003FF,		/* dst_mask.  */
	 TRUE),			/* pcrel_offset.  */
};
\f
/* Map BFD reloc types to MOXIE ELF reloc types.  */

struct moxie_reloc_map
{
  bfd_reloc_code_real_type bfd_reloc_val;
  unsigned int moxie_reloc_val;
};

static const struct moxie_reloc_map moxie_reloc_map [] =
{
  { BFD_RELOC_NONE,            R_MOXIE_NONE },
  { BFD_RELOC_32,              R_MOXIE_32 },
  { BFD_RELOC_MOXIE_10_PCREL,  R_MOXIE_PCREL10 },
};

static reloc_howto_type *
moxie_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
			 bfd_reloc_code_real_type code)
{
  unsigned int i;

  for (i = sizeof (moxie_reloc_map) / sizeof (moxie_reloc_map[0]);
       --i;)
    if (moxie_reloc_map [i].bfd_reloc_val == code)
      return & moxie_elf_howto_table [moxie_reloc_map[i].moxie_reloc_val];

  return NULL;
}

static reloc_howto_type *
moxie_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED, const char *r_name)
{
  unsigned int i;

  for (i = 0;
       i < sizeof (moxie_elf_howto_table) / sizeof (moxie_elf_howto_table[0]);
       i++)
    if (moxie_elf_howto_table[i].name != NULL
	&& strcasecmp (moxie_elf_howto_table[i].name, r_name) == 0)
      return &moxie_elf_howto_table[i];

  return NULL;
}

/* Set the howto pointer for an MOXIE ELF reloc.  */

static void
moxie_info_to_howto_rela (bfd *abfd ATTRIBUTE_UNUSED,
			  arelent *cache_ptr,
			  Elf_Internal_Rela *dst)
{
  unsigned int r_type;

  r_type = ELF32_R_TYPE (dst->r_info);
  BFD_ASSERT (r_type < (unsigned int) R_MOXIE_max);
  cache_ptr->howto = & moxie_elf_howto_table [r_type];
}
\f
/* Perform a single relocation.  By default we use the standard BFD
   routines, but a few relocs, we have to do them ourselves.  */

static bfd_reloc_status_type
moxie_final_link_relocate (reloc_howto_type *howto,
			   bfd *input_bfd,
			   asection *input_section,
			   bfd_byte *contents,
			   Elf_Internal_Rela *rel,
			   bfd_vma relocation)
{
  bfd_reloc_status_type r = bfd_reloc_ok;

  switch (howto->type)
    {
    default:
      r = _bfd_final_link_relocate (howto, input_bfd, input_section,
				    contents, rel->r_offset,
				    relocation, rel->r_addend);
    }

  return r;
}
\f
/* Relocate an MOXIE ELF section.

   The RELOCATE_SECTION function is called by the new ELF backend linker
   to handle the relocations for a section.

   The relocs are always passed as Rela structures; if the section
   actually uses Rel structures, the r_addend field will always be
   zero.

   This function is responsible for adjusting the section contents as
   necessary, and (if using Rela relocs and generating a relocatable
   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 relocatable 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 bfd_boolean
moxie_elf_relocate_section (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)
{
  Elf_Internal_Shdr *symtab_hdr;
  struct elf_link_hash_entry **sym_hashes;
  Elf_Internal_Rela *rel;
  Elf_Internal_Rela *relend;

  symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (input_bfd);
  relend     = relocs + input_section->reloc_count;

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

      r_type = ELF32_R_TYPE (rel->r_info);

      r_symndx = ELF32_R_SYM (rel->r_info);

      howto  = moxie_elf_howto_table + ELF32_R_TYPE (rel->r_info);
      h      = NULL;
      sym    = NULL;
      sec    = NULL;

      if (r_symndx < symtab_hdr->sh_info)
	{
	  sym = local_syms + r_symndx;
	  sec = local_sections [r_symndx];
	  relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);

	  name = bfd_elf_string_from_elf_section
	    (input_bfd, symtab_hdr->sh_link, sym->st_name);
	  name = (name == NULL) ? bfd_section_name (input_bfd, sec) : name;
	}
      else
	{
	  bfd_boolean unresolved_reloc, warned;

	  RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
				   r_symndx, symtab_hdr, sym_hashes,
				   h, sec, relocation,
				   unresolved_reloc, warned);

	  name = h->root.root.string;
	}

      if (sec != NULL && elf_discarded_section (sec))
	{
	  /* For relocs against symbols from removed linkonce sections,
	     or sections discarded by a linker script, we just want the
	     section contents zeroed.  Avoid any special processing.  */
	  _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
	  rel->r_info = 0;
	  rel->r_addend = 0;
	  continue;
	}

      if (info->relocatable)
	continue;

      r = moxie_final_link_relocate (howto, input_bfd, input_section,
				     contents, rel, relocation);

      if (r != bfd_reloc_ok)
	{
	  const char * msg = NULL;

	  switch (r)
	    {
	    case bfd_reloc_overflow:
	      r = info->callbacks->reloc_overflow
		(info, (h ? &h->root : NULL), name, howto->name,
		 (bfd_vma) 0, input_bfd, input_section, rel->r_offset);
	      break;

	    case bfd_reloc_undefined:
	      r = info->callbacks->undefined_symbol
		(info, name, input_bfd, input_section, rel->r_offset,
		 TRUE);
	      break;

	    case bfd_reloc_outofrange:
	      msg = _("internal error: out of range error");
	      break;

	    case bfd_reloc_notsupported:
	      msg = _("internal error: unsupported relocation error");
	      break;

	    case bfd_reloc_dangerous:
	      msg = _("internal error: dangerous relocation");
	      break;

	    default:
	      msg = _("internal error: unknown error");
	      break;
	    }

	  if (msg)
	    r = info->callbacks->warning
	      (info, msg, name, input_bfd, input_section, rel->r_offset);

	  if (! r)
	    return FALSE;
	}
    }

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

static asection *
moxie_elf_gc_mark_hook (asection *sec,
			struct bfd_link_info *info,
			Elf_Internal_Rela *rel,
			struct elf_link_hash_entry *h,
			Elf_Internal_Sym *sym)
{
  return _bfd_elf_gc_mark_hook (sec, info, rel, h, sym);
}

/* 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 bfd_boolean
moxie_elf_check_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;
  const Elf_Internal_Rela *rel;
  const Elf_Internal_Rela *rel_end;

  if (info->relocatable)
    return TRUE;

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

  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];
	  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;
	}
    }

  return TRUE;
}
\f
#define ELF_ARCH		bfd_arch_moxie
#define ELF_MACHINE_CODE	EM_MOXIE
#define ELF_MAXPAGESIZE		0x1

#define TARGET_BIG_SYM          bfd_elf32_moxie_vec
#define TARGET_BIG_NAME		"elf32-moxie"

#define elf_info_to_howto_rel			NULL
#define elf_info_to_howto			moxie_info_to_howto_rela
#define elf_backend_relocate_section		moxie_elf_relocate_section
#define elf_backend_gc_mark_hook		moxie_elf_gc_mark_hook
#define elf_backend_check_relocs                moxie_elf_check_relocs

#define elf_backend_can_gc_sections		1
#define elf_backend_rela_normal			1

#define bfd_elf32_bfd_reloc_type_lookup		moxie_reloc_type_lookup
#define bfd_elf32_bfd_reloc_name_lookup		moxie_reloc_name_lookup

#include "elf32-target.h"