elf32-arc.c   [plain text]

/* ARC-specific support for 32-bit ELF
   Copyright 1994, 1995, 1997, 1999, 2001 Free Software Foundation, Inc.
   Contributed by Doug Evans (dje@cygnus.com).

   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/arc.h"
#include "libiberty.h"

static reloc_howto_type *bfd_elf32_bfd_reloc_type_lookup
  PARAMS ((bfd *abfd, bfd_reloc_code_real_type code));
static void arc_info_to_howto_rel
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rel *));
static boolean arc_elf_object_p
  PARAMS ((bfd *));
static void arc_elf_final_write_processing
  PARAMS ((bfd *, boolean));
static bfd_reloc_status_type arc_elf_b22_pcrel
  PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));

/* Try to minimize the amount of space occupied by relocation tables
   on the ROM (not that the ROM won't be swamped by other ELF overhead).  */

#define USE_REL

static reloc_howto_type elf_arc_howto_table[] =
{
  /* This reloc does nothing.  */
  HOWTO (R_ARC_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_ARC_NONE",		/* name  */
	 true,			/* partial_inplace  */
	 0,			/* src_mask  */
	 0,			/* dst_mask  */
	 false),		/* pcrel_offset  */

  /* A standard 32 bit relocation.  */
  HOWTO (R_ARC_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_ARC_32",		/* name  */
	 true,			/* partial_inplace  */
	 0xffffffff,		/* src_mask  */
	 0xffffffff,		/* dst_mask  */
	 false),		/* pcrel_offset  */

  /* A 26 bit absolute branch, right shifted by 2.  */
  HOWTO (R_ARC_B26,		/* type  */
	 2,			/* rightshift  */
	 2,			/* size (0 = byte, 1 = short, 2 = long)  */
	 26,			/* bitsize  */
	 false,			/* pc_relative  */
	 0,			/* bitpos  */
	 complain_overflow_bitfield, /* complain_on_overflow  */
	 bfd_elf_generic_reloc,	/* special_function  */
	 "R_ARC_B26",		/* name  */
	 true,			/* partial_inplace  */
	 0x00ffffff,		/* src_mask  */
	 0x00ffffff,		/* dst_mask  */
	 false),		/* pcrel_offset  */

  /* A relative 22 bit branch; bits 21-2 are stored in bits 26-7.  */
  HOWTO (R_ARC_B22_PCREL,	/* type  */
	 2,			/* rightshift  */
	 2,			/* size (0 = byte, 1 = short, 2 = long)  */
	 22,			/* bitsize  */
	 true,			/* pc_relative  */
	 7,			/* bitpos  */
	 complain_overflow_signed, /* complain_on_overflow  */
	 arc_elf_b22_pcrel,	/* special_function  */
	 "R_ARC_B22_PCREL",	/* name  */
	 true,			/* partial_inplace  */
	 0x07ffff80,		/* src_mask  */
	 0x07ffff80,		/* dst_mask  */
	 false),		/* pcrel_offset  */
};

/* Map BFD reloc types to ARC ELF reloc types.  */

struct arc_reloc_map
{
  bfd_reloc_code_real_type bfd_reloc_val;
  unsigned char elf_reloc_val;
};

static const struct arc_reloc_map arc_reloc_map[] =
{
  { BFD_RELOC_NONE, R_ARC_NONE, },
  { BFD_RELOC_32, R_ARC_32 },
  { BFD_RELOC_CTOR, R_ARC_32 },
  { BFD_RELOC_ARC_B26, R_ARC_B26 },
  { BFD_RELOC_ARC_B22_PCREL, R_ARC_B22_PCREL },
};

static reloc_howto_type *
bfd_elf32_bfd_reloc_type_lookup (abfd, code)
     bfd *abfd ATTRIBUTE_UNUSED;
     bfd_reloc_code_real_type code;
{
  unsigned int i;

  for (i = ARRAY_SIZE (arc_reloc_map); i--;)
    if (arc_reloc_map[i].bfd_reloc_val == code)
      return elf_arc_howto_table + arc_reloc_map[i].elf_reloc_val;

  return NULL;
}

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

static void
arc_info_to_howto_rel (abfd, cache_ptr, dst)
     bfd *abfd ATTRIBUTE_UNUSED;
     arelent *cache_ptr;
     Elf32_Internal_Rel *dst;
{
  unsigned int r_type;

  r_type = ELF32_R_TYPE (dst->r_info);
  BFD_ASSERT (r_type < (unsigned int) R_ARC_max);
  cache_ptr->howto = &elf_arc_howto_table[r_type];
}

/* Set the right machine number for an ARC ELF file.  */

static boolean
arc_elf_object_p (abfd)
     bfd *abfd;
{
  unsigned int mach = bfd_mach_arc_6;

  if (elf_elfheader(abfd)->e_machine == EM_ARC)
    {
      unsigned long arch = elf_elfheader (abfd)->e_flags & EF_ARC_MACH;

      switch (arch)
	{
	case E_ARC_MACH_ARC5:
	  mach = bfd_mach_arc_5;
	  break;
	default:
	case E_ARC_MACH_ARC6:
	  mach = bfd_mach_arc_6;
	  break;
	case E_ARC_MACH_ARC7:
	  mach = bfd_mach_arc_7;
	  break;
	case E_ARC_MACH_ARC8:
	  mach = bfd_mach_arc_8;
	  break;
	}
    }
  return bfd_default_set_arch_mach (abfd, bfd_arch_arc, mach);
}

/* The final processing done just before writing out an ARC ELF object file.
   This gets the ARC architecture right based on the machine number.  */

static void
arc_elf_final_write_processing (abfd, linker)
     bfd *abfd;
     boolean linker ATTRIBUTE_UNUSED;
{
  unsigned long val;

  switch (bfd_get_mach (abfd))
    {
    case bfd_mach_arc_5:
      val = E_ARC_MACH_ARC5;
      break;
    default:
    case bfd_mach_arc_6:
      val = E_ARC_MACH_ARC6;
      break;
    case bfd_mach_arc_7:
      val = E_ARC_MACH_ARC7;
      break;
    case bfd_mach_arc_8:
      val = E_ARC_MACH_ARC8;
      break;
    }
  elf_elfheader (abfd)->e_flags &=~ EF_ARC_MACH;
  elf_elfheader (abfd)->e_flags |= val;
}

bfd_reloc_status_type
arc_elf_b22_pcrel (abfd, reloc_entry, symbol, data, input_section,
		   output_bfd, error_message)
     bfd * abfd;
     arelent * reloc_entry;
     asymbol * symbol;
     PTR data;
     asection * input_section;
     bfd * output_bfd;
     char ** error_message;
{
  /* If linking, back up the final symbol address by the address of the
     reloc.  This cannot be accomplished by setting the pcrel_offset
     field to true, as bfd_install_relocation will detect this and refuse
     to install the offset in the first place, but bfd_perform_relocation
     will still insist on removing it.  */
  if (output_bfd == (bfd *) NULL)
    reloc_entry->addend -= reloc_entry->address;

  /* Fall through to the default elf reloc handler.  */
  return bfd_elf_generic_reloc (abfd, reloc_entry, symbol, data,
				input_section, output_bfd, error_message);
}
  
#define TARGET_LITTLE_SYM bfd_elf32_littlearc_vec
#define TARGET_LITTLE_NAME "elf32-littlearc"
#define TARGET_BIG_SYM bfd_elf32_bigarc_vec
#define TARGET_BIG_NAME	"elf32-bigarc"
#define ELF_ARCH bfd_arch_arc
#define ELF_MACHINE_CODE EM_ARC
#define ELF_MAXPAGESIZE	0x1000

#define elf_info_to_howto 0
#define elf_info_to_howto_rel arc_info_to_howto_rel
#define elf_backend_object_p arc_elf_object_p
#define elf_backend_final_write_processing arc_elf_final_write_processing

#include "elf32-target.h"