elf32-mcore.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 750 行 · 第 1/2 页

/* Motorola MCore specific support for 32-bit ELF
   Copyright 1994, 1995, 1999, 2000, 2001 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 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.  */

/* This file is based on a preliminary RCE ELF ABI.  The
   information may not match the final RCE ELF ABI.   */

#include "bfd.h"
#include "sysdep.h"
#include "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf/mcore.h"
#include <assert.h>

#define	USE_RELA	/* Only USE_REL is actually significant, but this is
			   here are a reminder...  */

static void mcore_elf_howto_init
  PARAMS ((void));
static reloc_howto_type * mcore_elf_reloc_type_lookup
  PARAMS ((bfd *, bfd_reloc_code_real_type));
static void mcore_elf_info_to_howto
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *));
static boolean mcore_elf_set_private_flags
  PARAMS ((bfd *, flagword));
static boolean mcore_elf_copy_private_bfd_data
  PARAMS ((bfd *, bfd *));
static boolean mcore_elf_merge_private_bfd_data
  PARAMS ((bfd *, bfd *));
static bfd_reloc_status_type mcore_elf_unsupported_reloc
  PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
static boolean mcore_elf_relocate_section
  PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
	   Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));

static reloc_howto_type * mcore_elf_howto_table [(int) R_MCORE_max];

static reloc_howto_type mcore_elf_howto_raw[] =
{
  /* This reloc does nothing.  */
  HOWTO (R_MCORE_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 */
	 NULL,                  /* special_function */
	 "R_MCORE_NONE",	/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),		/* pcrel_offset */

  /* A standard 32 bit relocation.  */
  HOWTO (R_MCORE_ADDR32,	/* 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 */
	 "ADDR32",		/* name *//* For compatability with coff/pe port.  */
	 false,			/* partial_inplace */
	 0x0,			/* src_mask */
	 0xffffffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* 8 bits + 2 zero bits; jmpi/jsri/lrw instructions.
     Should not appear in object files.  */
  HOWTO (R_MCORE_PCRELIMM8BY4,	/* type */
	 2,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 mcore_elf_unsupported_reloc,	/* special_function */
	 "R_MCORE_PCRELIMM8BY4",/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 true),			/* pcrel_offset */

  /* bsr/bt/bf/br instructions; 11 bits + 1 zero bit
     Span 2k instructions == 4k bytes.
     Only useful pieces at the relocated address are the opcode (5 bits) */
  HOWTO (R_MCORE_PCRELIMM11BY2,/* type */
	 1,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 11,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_signed, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_MCORE_PCRELIMM11BY2",/* name */
	 false,			/* partial_inplace */
	 0x0,			/* src_mask */
	 0x7ff,			/* dst_mask */
	 true),			/* pcrel_offset */

  /* 4 bits + 1 zero bit; 'loopt' instruction only; unsupported.  */
  HOWTO (R_MCORE_PCRELIMM4BY2,	/* type */
	 1,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 4,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 mcore_elf_unsupported_reloc,/* special_function */
	 "R_MCORE_PCRELIMM4BY2",/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 true),			/* pcrel_offset */

  /* 32-bit pc-relative. Eventually this will help support PIC code.  */
  HOWTO (R_MCORE_PCREL32,	/* 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_MCORE_PCREL32",	/* name */
	 false,			/* partial_inplace */
	 0x0,			/* src_mask */
	 0xffffffff,		/* dst_mask */
	 true),			/* pcrel_offset */

  /* Like PCRELIMM11BY2, this relocation indicates that there is a
     'jsri' at the specified address. There is a separate relocation
     entry for the literal pool entry that it references, but we
     might be able to change the jsri to a bsr if the target turns out
     to be close enough [even though we won't reclaim the literal pool
     entry, we'll get some runtime efficiency back]. Note that this
     is a relocation that we are allowed to safely ignore.  */
  HOWTO (R_MCORE_PCRELJSR_IMM11BY2,/* type */
	 1,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 11,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_signed, /* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_MCORE_PCRELJSR_IMM11BY2", /* name */
	 false,			/* partial_inplace */
	 0x0,			/* src_mask */
	 0x7ff,			/* dst_mask */
	 true),			/* pcrel_offset */

  /* GNU extension to record C++ vtable hierarchy */
  HOWTO (R_MCORE_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_MCORE_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_MCORE_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_MCORE_GNU_VTENTRY", /* name */
         false,                 /* partial_inplace */
         0,                     /* src_mask */
         0,                     /* dst_mask */
         false),                /* pcrel_offset */

  HOWTO (R_MCORE_RELATIVE,      /* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_signed, /* complain_on_overflow */
	 NULL,                  /* special_function */
	 "R_MCORE_RELATIVE",    /* name */
	 true,			/* partial_inplace */
	 0xffffffff,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 false)			/* pcrel_offset */
};

#ifndef NUM_ELEM
#define NUM_ELEM(a) (sizeof (a) / sizeof (a)[0])
#endif

/* Initialize the mcore_elf_howto_table, so that linear accesses can be done.  */
static void
mcore_elf_howto_init ()
{
  unsigned int i;

  for (i = NUM_ELEM (mcore_elf_howto_raw); i--;)
    {
      unsigned int type;

      type = mcore_elf_howto_raw[i].type;

      BFD_ASSERT (type < NUM_ELEM (mcore_elf_howto_table));

      mcore_elf_howto_table [type] = & mcore_elf_howto_raw [i];
    }
}

static reloc_howto_type *
mcore_elf_reloc_type_lookup (abfd, code)
     bfd * abfd ATTRIBUTE_UNUSED;
     bfd_reloc_code_real_type code;
{
  enum elf_mcore_reloc_type mcore_reloc = R_MCORE_NONE;

  switch (code)
    {
    case BFD_RELOC_NONE:		     mcore_reloc = R_MCORE_NONE; break;
    case BFD_RELOC_32:			     mcore_reloc = R_MCORE_ADDR32; break;
    case BFD_RELOC_MCORE_PCREL_IMM8BY4:	     mcore_reloc = R_MCORE_PCRELIMM8BY4; break;
    case BFD_RELOC_MCORE_PCREL_IMM11BY2:     mcore_reloc = R_MCORE_PCRELIMM11BY2; break;
    case BFD_RELOC_MCORE_PCREL_IMM4BY2:	     mcore_reloc = R_MCORE_PCRELIMM4BY2; break;
    case BFD_RELOC_32_PCREL:		     mcore_reloc = R_MCORE_PCREL32; break;
    case BFD_RELOC_MCORE_PCREL_JSR_IMM11BY2: mcore_reloc = R_MCORE_PCRELJSR_IMM11BY2; break;
    case BFD_RELOC_VTABLE_INHERIT:           mcore_reloc = R_MCORE_GNU_VTINHERIT; break;
    case BFD_RELOC_VTABLE_ENTRY:             mcore_reloc = R_MCORE_GNU_VTENTRY; break;
    case BFD_RELOC_RVA:                      mcore_reloc = R_MCORE_RELATIVE; break;
    default:
      return (reloc_howto_type *)NULL;
    }

  if (! mcore_elf_howto_table [R_MCORE_PCRELIMM8BY4])	/* Initialize howto table if needed */
    mcore_elf_howto_init ();

  return mcore_elf_howto_table [(int) mcore_reloc];
};

/* Set the howto pointer for a RCE ELF reloc.  */
static void
mcore_elf_info_to_howto (abfd, cache_ptr, dst)
     bfd * abfd ATTRIBUTE_UNUSED;
     arelent * cache_ptr;
     Elf32_Internal_Rela * dst;
{
  if (! mcore_elf_howto_table [R_MCORE_PCRELIMM8BY4])	/* Initialize howto table if needed */
    mcore_elf_howto_init ();

  BFD_ASSERT (ELF32_R_TYPE (dst->r_info) < (unsigned int) R_MCORE_max);

  cache_ptr->howto = mcore_elf_howto_table [ELF32_R_TYPE (dst->r_info)];
}

/* Function to set whether a module needs the -mrelocatable bit set.  */
static boolean
mcore_elf_set_private_flags (abfd, flags)
     bfd * abfd;
     flagword flags;
{
  BFD_ASSERT (! elf_flags_init (abfd)
	      || elf_elfheader (abfd)->e_flags == flags);

  elf_elfheader (abfd)->e_flags = flags;
  elf_flags_init (abfd) = true;
  return true;
}

/* Copy backend specific data from one object module to another.  */
static boolean
mcore_elf_copy_private_bfd_data (ibfd, obfd)
     bfd * ibfd;
     bfd * obfd;
{
  if (   bfd_get_flavour (ibfd) != bfd_target_elf_flavour
      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
    return true;

  BFD_ASSERT (! elf_flags_init (obfd)
	      || elf_elfheader (obfd)->e_flags == elf_elfheader (ibfd)->e_flags);

  elf_elfheader (obfd)->e_flags = elf_elfheader (ibfd)->e_flags;
  elf_flags_init (obfd) = true;
  return true;
}

/* Merge backend specific data from an object file to the output
   object file when linking.  */
static boolean
mcore_elf_merge_private_bfd_data (ibfd, obfd)
     bfd * ibfd;
     bfd * obfd;
{
  flagword old_flags;
  flagword new_flags;

  /* Check if we have the same endianess */
  if (_bfd_generic_verify_endian_match (ibfd, obfd) == false)
    return false;

  if (   bfd_get_flavour (ibfd) != bfd_target_elf_flavour
      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
    return true;

  new_flags = elf_elfheader (ibfd)->e_flags;
  old_flags = elf_elfheader (obfd)->e_flags;

  if (! elf_flags_init (obfd))	/* First call, no flags set */
    {
      elf_flags_init (obfd) = true;
      elf_elfheader (obfd)->e_flags = new_flags;
    }
  else if (new_flags == old_flags)	/* Compatible flags are ok */
    ;
  else
    {
      /* FIXME */
    }

  return true;
}

/* Don't pretend we can deal with unsupported relocs.  */

static bfd_reloc_status_type
mcore_elf_unsupported_reloc (abfd, reloc_entry, symbol, data, input_section,
			   output_bfd, error_message)
     bfd * abfd;
     arelent * reloc_entry;
     asymbol * symbol ATTRIBUTE_UNUSED;
     PTR data ATTRIBUTE_UNUSED;
     asection * input_section ATTRIBUTE_UNUSED;
     bfd * output_bfd ATTRIBUTE_UNUSED;
     char ** error_message ATTRIBUTE_UNUSED;
{
  BFD_ASSERT (reloc_entry->howto != (reloc_howto_type *)0);

  _bfd_error_handler (_("%s: Relocation %s (%d) is not currently supported.\n"),
		      bfd_get_filename (abfd),
		      reloc_entry->howto->name,
		      reloc_entry->howto->type);

  return bfd_reloc_notsupported;
}

/* The RELOCATE_SECTION function is called by the ELF backend linker
   to handle the relocations for a section.

   The relocs are always passed as Rela structures; if the section