elf32-i386.c

基于4个mips核的noc设计

/* Intel 80386/80486-specific support for 32-bit ELF
   Copyright 1993, 1994, 1995, 1996, 1997, 1998, 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.  */

#include "bfd.h"
#include "sysdep.h"
#include "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"

static reloc_howto_type *elf_i386_reloc_type_lookup
  PARAMS ((bfd *, bfd_reloc_code_real_type));
static void elf_i386_info_to_howto
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *));
static void elf_i386_info_to_howto_rel
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rel *));
static boolean elf_i386_is_local_label_name PARAMS ((bfd *, const char *));
static struct bfd_hash_entry *elf_i386_link_hash_newfunc
  PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
static struct bfd_link_hash_table *elf_i386_link_hash_table_create
  PARAMS ((bfd *));
static boolean elf_i386_check_relocs
  PARAMS ((bfd *, struct bfd_link_info *, asection *,
	   const Elf_Internal_Rela *));
static boolean elf_i386_adjust_dynamic_symbol
  PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
static boolean elf_i386_size_dynamic_sections
  PARAMS ((bfd *, struct bfd_link_info *));
static boolean elf_i386_relocate_section
  PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
	   Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
static boolean elf_i386_finish_dynamic_symbol
  PARAMS ((bfd *, struct bfd_link_info *, struct elf_link_hash_entry *,
	   Elf_Internal_Sym *));
static boolean elf_i386_finish_dynamic_sections
  PARAMS ((bfd *, struct bfd_link_info *));

#define USE_REL	1		/* 386 uses REL relocations instead of RELA */

#include "elf/i386.h"

static reloc_howto_type elf_howto_table[]=
{
  HOWTO(R_386_NONE, 0, 0, 0, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_NONE",
	true, 0x00000000, 0x00000000, false),
  HOWTO(R_386_32, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_32",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_PC32, 0, 2, 32, true, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_PC32",
	true, 0xffffffff, 0xffffffff, true),
  HOWTO(R_386_GOT32, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_GOT32",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_PLT32, 0, 2, 32, true, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_PLT32",
	true, 0xffffffff, 0xffffffff, true),
  HOWTO(R_386_COPY, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_COPY",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_GLOB_DAT, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_GLOB_DAT",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_JUMP_SLOT, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_JUMP_SLOT",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_RELATIVE, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_RELATIVE",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_GOTOFF, 0, 2, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_GOTOFF",
	true, 0xffffffff, 0xffffffff, false),
  HOWTO(R_386_GOTPC, 0, 2, 32, true, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_GOTPC",
	true, 0xffffffff, 0xffffffff, true),

  /* We have a gap in the reloc numbers here.
     R_386_standard counts the number up to this point, and
     R_386_ext_offset is the value to subtract from a reloc type of
     R_386_16 thru R_386_PC8 to form an index into this table.  */
#define R_386_standard ((unsigned int) R_386_GOTPC + 1)
#define R_386_ext_offset ((unsigned int) R_386_16 - R_386_standard)

  /* The remaining relocs are a GNU extension.  */
  HOWTO(R_386_16, 0, 1, 16, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_16",
	true, 0xffff, 0xffff, false),
  HOWTO(R_386_PC16, 0, 1, 16, true, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_PC16",
	true, 0xffff, 0xffff, true),
  HOWTO(R_386_8, 0, 0, 8, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_386_8",
	true, 0xff, 0xff, false),
  HOWTO(R_386_PC8, 0, 0, 8, true, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_386_PC8",
	true, 0xff, 0xff, true),

  /* Another gap.  */
#define R_386_ext ((unsigned int) R_386_PC8 + 1 - R_386_ext_offset)
#define R_386_vt_offset ((unsigned int) R_386_GNU_VTINHERIT - R_386_ext)

/* GNU extension to record C++ vtable hierarchy.  */
  HOWTO (R_386_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_386_GNU_VTINHERIT",	/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),

/* GNU extension to record C++ vtable member usage.  */
  HOWTO (R_386_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_386_GNU_VTENTRY",	/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false)

#define R_386_vt ((unsigned int) R_386_GNU_VTENTRY + 1 - R_386_vt_offset)

};

#ifdef DEBUG_GEN_RELOC
#define TRACE(str) fprintf (stderr, "i386 bfd reloc lookup %d (%s)\n", code, str)
#else
#define TRACE(str)
#endif

static reloc_howto_type *
elf_i386_reloc_type_lookup (abfd, code)
     bfd *abfd ATTRIBUTE_UNUSED;
     bfd_reloc_code_real_type code;
{
  switch (code)
    {
    case BFD_RELOC_NONE:
      TRACE ("BFD_RELOC_NONE");
      return &elf_howto_table[(unsigned int) R_386_NONE ];

    case BFD_RELOC_32:
      TRACE ("BFD_RELOC_32");
      return &elf_howto_table[(unsigned int) R_386_32 ];

    case BFD_RELOC_CTOR:
      TRACE ("BFD_RELOC_CTOR");
      return &elf_howto_table[(unsigned int) R_386_32 ];

    case BFD_RELOC_32_PCREL:
      TRACE ("BFD_RELOC_PC32");
      return &elf_howto_table[(unsigned int) R_386_PC32 ];

    case BFD_RELOC_386_GOT32:
      TRACE ("BFD_RELOC_386_GOT32");
      return &elf_howto_table[(unsigned int) R_386_GOT32 ];

    case BFD_RELOC_386_PLT32:
      TRACE ("BFD_RELOC_386_PLT32");
      return &elf_howto_table[(unsigned int) R_386_PLT32 ];

    case BFD_RELOC_386_COPY:
      TRACE ("BFD_RELOC_386_COPY");
      return &elf_howto_table[(unsigned int) R_386_COPY ];

    case BFD_RELOC_386_GLOB_DAT:
      TRACE ("BFD_RELOC_386_GLOB_DAT");
      return &elf_howto_table[(unsigned int) R_386_GLOB_DAT ];

    case BFD_RELOC_386_JUMP_SLOT:
      TRACE ("BFD_RELOC_386_JUMP_SLOT");
      return &elf_howto_table[(unsigned int) R_386_JUMP_SLOT ];

    case BFD_RELOC_386_RELATIVE:
      TRACE ("BFD_RELOC_386_RELATIVE");
      return &elf_howto_table[(unsigned int) R_386_RELATIVE ];

    case BFD_RELOC_386_GOTOFF:
      TRACE ("BFD_RELOC_386_GOTOFF");
      return &elf_howto_table[(unsigned int) R_386_GOTOFF ];

    case BFD_RELOC_386_GOTPC:
      TRACE ("BFD_RELOC_386_GOTPC");
      return &elf_howto_table[(unsigned int) R_386_GOTPC ];

      /* The remaining relocs are a GNU extension.  */
    case BFD_RELOC_16:
      TRACE ("BFD_RELOC_16");
      return &elf_howto_table[(unsigned int) R_386_16 - R_386_ext_offset];

    case BFD_RELOC_16_PCREL:
      TRACE ("BFD_RELOC_16_PCREL");
      return &elf_howto_table[(unsigned int) R_386_PC16 - R_386_ext_offset];

    case BFD_RELOC_8:
      TRACE ("BFD_RELOC_8");
      return &elf_howto_table[(unsigned int) R_386_8 - R_386_ext_offset];

    case BFD_RELOC_8_PCREL:
      TRACE ("BFD_RELOC_8_PCREL");
      return &elf_howto_table[(unsigned int) R_386_PC8 - R_386_ext_offset];

    case BFD_RELOC_VTABLE_INHERIT:
      TRACE ("BFD_RELOC_VTABLE_INHERIT");
      return &elf_howto_table[(unsigned int) R_386_GNU_VTINHERIT
			     - R_386_vt_offset];

    case BFD_RELOC_VTABLE_ENTRY:
      TRACE ("BFD_RELOC_VTABLE_ENTRY");
      return &elf_howto_table[(unsigned int) R_386_GNU_VTENTRY
			     - R_386_vt_offset];

    default:
      break;
    }

  TRACE ("Unknown");
  return 0;
}

static void
elf_i386_info_to_howto (abfd, cache_ptr, dst)
     bfd		*abfd ATTRIBUTE_UNUSED;
     arelent		*cache_ptr ATTRIBUTE_UNUSED;
     Elf32_Internal_Rela *dst ATTRIBUTE_UNUSED;
{
  abort ();
}

static void
elf_i386_info_to_howto_rel (abfd, cache_ptr, dst)
     bfd *abfd ATTRIBUTE_UNUSED;
     arelent *cache_ptr;
     Elf32_Internal_Rel *dst;
{
  unsigned int r_type = ELF32_R_TYPE (dst->r_info);
  unsigned int indx;

  if ((indx = r_type) >= R_386_standard
      && ((indx = r_type - R_386_ext_offset) - R_386_standard
	  >= R_386_ext - R_386_standard)
      && ((indx = r_type - R_386_vt_offset) - R_386_ext
	  >= R_386_vt - R_386_ext))
    {
      (*_bfd_error_handler) (_("%s: invalid relocation type %d"),
			     bfd_get_filename (abfd), (int) r_type);
      indx = (unsigned int) R_386_NONE;
    }
  cache_ptr->howto = &elf_howto_table[indx];
}

/* Return whether a symbol name implies a local label.  The UnixWare
   2.1 cc generates temporary symbols that start with .X, so we
   recognize them here.  FIXME: do other SVR4 compilers also use .X?.
   If so, we should move the .X recognition into
   _bfd_elf_is_local_label_name.  */

static boolean
elf_i386_is_local_label_name (abfd, name)
     bfd *abfd;
     const char *name;
{
  if (name[0] == '.' && name[1] == 'X')
    return true;

  return _bfd_elf_is_local_label_name (abfd, name);
}

/* Functions for the i386 ELF linker.  */

/* The name of the dynamic interpreter.  This is put in the .interp
   section.  */

#define ELF_DYNAMIC_INTERPRETER "/usr/lib/libc.so.1"

/* The size in bytes of an entry in the procedure linkage table.  */

#define PLT_ENTRY_SIZE 16

/* The first entry in an absolute procedure linkage table looks like
   this.  See the SVR4 ABI i386 supplement to see how this works.  */

static const bfd_byte elf_i386_plt0_entry[PLT_ENTRY_SIZE] =
{
  0xff, 0x35,	/* pushl contents of address */
  0, 0, 0, 0,	/* replaced with address of .got + 4.  */
  0xff, 0x25,	/* jmp indirect */
  0, 0, 0, 0,	/* replaced with address of .got + 8.  */
  0, 0, 0, 0	/* pad out to 16 bytes.  */
};

/* Subsequent entries in an absolute procedure linkage table look like
   this.  */

static const bfd_byte elf_i386_plt_entry[PLT_ENTRY_SIZE] =
{
  0xff, 0x25,	/* jmp indirect */
  0, 0, 0, 0,	/* replaced with address of this symbol in .got.  */
  0x68,		/* pushl immediate */
  0, 0, 0, 0,	/* replaced with offset into relocation table.  */
  0xe9,		/* jmp relative */
  0, 0, 0, 0	/* replaced with offset to start of .plt.  */
};

/* The first entry in a PIC procedure linkage table look like this.  */

static const bfd_byte elf_i386_pic_plt0_entry[PLT_ENTRY_SIZE] =
{
  0xff, 0xb3, 4, 0, 0, 0,	/* pushl 4(%ebx) */
  0xff, 0xa3, 8, 0, 0, 0,	/* jmp *8(%ebx) */
  0, 0, 0, 0			/* pad out to 16 bytes.  */
};

/* Subsequent entries in a PIC procedure linkage table look like this.  */

static const bfd_byte elf_i386_pic_plt_entry[PLT_ENTRY_SIZE] =
{
  0xff, 0xa3,	/* jmp *offset(%ebx) */
  0, 0, 0, 0,	/* replaced with offset of this symbol in .got.  */
  0x68,		/* pushl immediate */
  0, 0, 0, 0,	/* replaced with offset into relocation table.  */
  0xe9,		/* jmp relative */
  0, 0, 0, 0	/* replaced with offset to start of .plt.  */
};

/* The i386 linker needs to keep track of the number of relocs that it
   decides to copy in check_relocs for each symbol.  This is so that
   it can discard PC relative relocs if it doesn't need them when
   linking with -Bsymbolic.  We store the information in a field
   extending the regular ELF linker hash table.  */

/* This structure keeps track of the number of PC relative relocs we
   have copied for a given symbol.  */

struct elf_i386_pcrel_relocs_copied
{
  /* Next section.  */
  struct elf_i386_pcrel_relocs_copied *next;
  /* A section in dynobj.  */
  asection *section;
  /* Number of relocs copied in this section.  */
  bfd_size_type count;
};

/* i386 ELF linker hash entry.  */

struct elf_i386_link_hash_entry
{
  struct elf_link_hash_entry root;

  /* Number of PC relative relocs copied for this symbol.  */
  struct elf_i386_pcrel_relocs_copied *pcrel_relocs_copied;
};

/* i386 ELF linker hash table.  */

struct elf_i386_link_hash_table
{
  struct elf_link_hash_table root;
};

/* Declare this now that the above structures are defined.  */

static boolean elf_i386_discard_copies
  PARAMS ((struct elf_i386_link_hash_entry *, PTR));

/* Traverse an i386 ELF linker hash table.  */

#define elf_i386_link_hash_traverse(table, func, info)			\
  (elf_link_hash_traverse						\
   (&(table)->root,							\
    (boolean (*) PARAMS ((struct elf_link_hash_entry *, PTR))) (func),	\
    (info)))

/* Get the i386 ELF linker hash table from a link_info structure.  */

#define elf_i386_hash_table(p) \
  ((struct elf_i386_link_hash_table *) ((p)->hash))

/* Create an entry in an i386 ELF linker hash table.  */

static struct bfd_hash_entry *
elf_i386_link_hash_newfunc (entry, table, string)
     struct bfd_hash_entry *entry;
     struct bfd_hash_table *table;
     const char *string;
{
  struct elf_i386_link_hash_entry *ret =
    (struct elf_i386_link_hash_entry *) entry;

  /* Allocate the structure if it has not already been allocated by a
     subclass.  */
  if (ret == (struct elf_i386_link_hash_entry *) NULL)
    ret = ((struct elf_i386_link_hash_entry *)
	   bfd_hash_allocate (table,
			      sizeof (struct elf_i386_link_hash_entry)));
  if (ret == (struct elf_i386_link_hash_entry *) NULL)
    return (struct bfd_hash_entry *) ret;

  /* Call the allocation method of the superclass.  */
  ret = ((struct elf_i386_link_hash_entry *)
	 _bfd_elf_link_hash_newfunc ((struct bfd_hash_entry *) ret,
				     table, string));