binutils-gdb/bfd/elf32-cris.c

/* CRIS-specific support for 32-bit ELF.
   Copyright (C) 2000 Free Software Foundation, Inc.
   Contributed by Axis Communications AB.
   Written by Hans-Peter Nilsson, based on elf32-fr30.c

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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

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

/* Forward declarations.  */
static reloc_howto_type * cris_reloc_type_lookup
  PARAMS ((bfd *abfd, bfd_reloc_code_real_type code));

static void cris_info_to_howto_rela 
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *));

static boolean cris_elf_relocate_section 
  PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
	   Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));

static bfd_reloc_status_type cris_final_link_relocate
  PARAMS ((reloc_howto_type *, bfd *, asection *, bfd_byte *,
	   Elf_Internal_Rela *, bfd_vma));

static boolean cris_elf_gc_sweep_hook
  PARAMS ((bfd *, struct bfd_link_info *, asection *,
	   const Elf_Internal_Rela *));

static asection * cris_elf_gc_mark_hook
  PARAMS ((bfd *, struct bfd_link_info *, Elf_Internal_Rela *,
	   struct elf_link_hash_entry *, Elf_Internal_Sym *));

static reloc_howto_type cris_elf_howto_table [] =
{
  /* This reloc does nothing.  */
  HOWTO (R_CRIS_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_CRIS_NONE",		/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),		/* pcrel_offset */

  /* An 8 bit absolute relocation.  */
  HOWTO (R_CRIS_8,		/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_CRIS_8",		/* name */
	 false,			/* partial_inplace */
	 0x0000,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 16 bit absolute relocation.  */
  HOWTO (R_CRIS_16,		/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_CRIS_16",		/* name */
	 false,			/* partial_inplace */
	 0x00000000,		/* src_mask */
	 0x0000ffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 32 bit absolute relocation.  */
  HOWTO (R_CRIS_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_CRIS_32",		/* name */
	 false,			/* partial_inplace */
	 0x00000000,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* An 8 bit absolute relocation.  */
  HOWTO (R_CRIS_8_PCREL,	/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_CRIS_8_PCREL",	/* name */
	 false,			/* partial_inplace */
	 0x0000,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 16 bit absolute relocation.  */
  HOWTO (R_CRIS_16_PCREL,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_CRIS_16",		/* name */
	 false,			/* partial_inplace */
	 0x00000000,		/* src_mask */
	 0x0000ffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 32 bit absolute relocation.  */
  HOWTO (R_CRIS_32_PCREL,	/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_CRIS_32",		/* name */
	 false,			/* partial_inplace */
	 0x00000000,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* GNU extension to record C++ vtable hierarchy */
  HOWTO (R_CRIS_GNU_VTINHERIT, /* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 0,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 NULL,			/* special_function */
	 "R_CRIS_GNU_VTINHERIT", /* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),		/* pcrel_offset */

  /* GNU extension to record C++ vtable member usage */
  HOWTO (R_CRIS_GNU_VTENTRY,	 /* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 0,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 _bfd_elf_rel_vtable_reloc_fn,	/* special_function */
	 "R_CRIS_GNU_VTENTRY",	 /* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false)			/* pcrel_offset */
};

/* Map BFD reloc types to CRIS ELF reloc types.  */

struct cris_reloc_map
{
  bfd_reloc_code_real_type bfd_reloc_val;
  unsigned int cris_reloc_val;
};

static const struct cris_reloc_map cris_reloc_map [] =
{
  { BFD_RELOC_NONE,		R_CRIS_NONE },
  { BFD_RELOC_8,		R_CRIS_8 },
  { BFD_RELOC_16,		R_CRIS_16 },
  { BFD_RELOC_32,		R_CRIS_32 },
  { BFD_RELOC_8_PCREL,		R_CRIS_8_PCREL },
  { BFD_RELOC_16_PCREL,		R_CRIS_16_PCREL },
  { BFD_RELOC_32_PCREL,		R_CRIS_32_PCREL },
  { BFD_RELOC_VTABLE_INHERIT,	R_CRIS_GNU_VTINHERIT },
  { BFD_RELOC_VTABLE_ENTRY,	R_CRIS_GNU_VTENTRY }
};

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

  for (i = sizeof (cris_reloc_map) / sizeof (cris_reloc_map[0]);
       --i;)
    if (cris_reloc_map [i].bfd_reloc_val == code)
      return & cris_elf_howto_table [cris_reloc_map[i].cris_reloc_val];
  
  return NULL;
}

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

static void
cris_info_to_howto_rela (abfd, cache_ptr, dst)
     bfd * abfd ATTRIBUTE_UNUSED;
     arelent * cache_ptr;
     Elf32_Internal_Rela * dst;
{
  unsigned int r_type;

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

static bfd_reloc_status_type
cris_final_link_relocate (howto, input_bfd, input_section, contents, rel,
			  relocation)
     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_final_link_relocate (howto, input_bfd, input_section,
				contents, rel->r_offset,
				relocation, rel->r_addend);
  return r;
}

/* Relocate an CRIS ELF section.  See elf32-fr30.c, from where this was
   copied, for further comments.  */

static boolean
cris_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;
  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;

  /* It seems this can happen with erroneous or unsupported input (mixing
     a.out and elf in an archive, for example.)  */
  if (sym_hashes == NULL)
    return false;

  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 = NULL;
      int                          r_type;
      
      r_type = ELF32_R_TYPE (rel->r_info);
      
      if (   r_type == R_CRIS_GNU_VTINHERIT
	  || r_type == R_CRIS_GNU_VTENTRY)
	continue;
      
      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 (ELF_ST_TYPE (sym->st_info) == STT_SECTION)
		{
		  sec = local_sections [r_symndx];
		  rel->r_addend += sec->output_offset + sym->st_value;
		}
	    }

	  continue;
	}

      /* This is a final link.  */
      howto  = cris_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 = (sec->output_section->vma
			+ sec->output_offset
			+ sym->st_value);
	  
	  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;
#if 0
	  fprintf (stderr, "local: sec: %s, sym: %s (%d), value: %x + %x + %x addend %x\n",
		   sec->name, name, sym->st_name,
		   sec->output_section->vma, sec->output_offset,
		   sym->st_value, rel->r_addend);
#endif
	}
      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;

	  name = h->root.root.string;
	  
	  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);
#if 0
	      fprintf (stderr,
		       "defined: sec: %s, name: %s, value: %x + %x + %x gives: %x\n",
		       sec->name, name, h->root.u.def.value,
		       sec->output_section->vma, sec->output_offset, relocation);
#endif
	    }
	  else if (h->root.type == bfd_link_hash_undefweak)
	    {
#if 0
	      fprintf (stderr, "undefined: sec: %s, name: %s\n",
		       sec->name, name);
#endif
	      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;
#if 0
	      fprintf (stderr, "unknown: name: %s\n", name);
#endif
	      relocation = 0;
	    }
	}
      
      r = cris_final_link_relocate (howto, input_bfd, input_section,
				     contents, rel, relocation);

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

	  switch (r)
	    {
	    case bfd_reloc_overflow:
	      r = info->callbacks->reloc_overflow
		(info, 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;
}

/* Return the section that should be marked against GC for a given
   relocation.  */

static asection *
cris_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_CRIS_GNU_VTINHERIT:
	case R_CRIS_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
cris_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
cris_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, **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_CRIS_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_CRIS_GNU_VTENTRY:
          if (!_bfd_elf32_gc_record_vtentry (abfd, sec, h, rel->r_addend))
            return false;
          break;
        }
    }
 
  return true;
}

#define ELF_ARCH		bfd_arch_cris
#define ELF_MACHINE_CODE	EM_CRIS
#define ELF_MAXPAGESIZE		0x2000

#define TARGET_LITTLE_SYM	bfd_elf32_cris_vec
#define TARGET_LITTLE_NAME	"elf32-cris"

/* For the time being, we have a leading underscore.  Perhaps change to 0
   later, when
   1) a.out isn't as dominating, and we can forget about multiformat links
      and old assembly code.
   2) there's an official solution to the symbol vs. register duality
      problem; perhaps a % register prefix, optionally enforced.  */
#define elf_symbol_leading_char '_'

#define elf_info_to_howto_rel			NULL
#define elf_info_to_howto			cris_info_to_howto_rela
#define elf_backend_relocate_section		cris_elf_relocate_section
#define elf_backend_gc_mark_hook		cris_elf_gc_mark_hook
#define elf_backend_gc_sweep_hook		cris_elf_gc_sweep_hook
#define elf_backend_check_relocs                cris_elf_check_relocs

#define elf_backend_can_gc_sections		1

#define bfd_elf32_bfd_reloc_type_lookup		cris_reloc_type_lookup

/* Later, we my want to optimize RELA entries into REL entries for dynamic
   linking and libraries (if it's a win of any significance).  Until then,
   take the easy route.  */
#define elf_backend_may_use_rel_p 0
#define elf_backend_may_use_rela_p 1

#include "elf32-target.h"