elf32-m68k.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 2,163 行 · 第 1/5 页

/* Motorola 68k series support for 32-bit ELF
   Copyright 1993, 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"
#include "elf/m68k.h"

static reloc_howto_type *reloc_type_lookup
  PARAMS ((bfd *, bfd_reloc_code_real_type));
static void rtype_to_howto
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *));
static struct bfd_hash_entry *elf_m68k_link_hash_newfunc
  PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
static struct bfd_link_hash_table *elf_m68k_link_hash_table_create
  PARAMS ((bfd *));
static boolean elf_m68k_check_relocs
  PARAMS ((bfd *, struct bfd_link_info *, asection *,
	   const Elf_Internal_Rela *));
static asection *elf_m68k_gc_mark_hook
  PARAMS ((bfd *, struct bfd_link_info *, Elf_Internal_Rela *,
	   struct elf_link_hash_entry *, Elf_Internal_Sym *));
static boolean elf_m68k_gc_sweep_hook
  PARAMS ((bfd *, struct bfd_link_info *, asection *,
	   const Elf_Internal_Rela *));
static boolean elf_m68k_adjust_dynamic_symbol
  PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
static boolean elf_m68k_size_dynamic_sections
  PARAMS ((bfd *, struct bfd_link_info *));
static boolean elf_m68k_relocate_section
  PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
	   Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
static boolean elf_m68k_finish_dynamic_symbol
  PARAMS ((bfd *, struct bfd_link_info *, struct elf_link_hash_entry *,
	   Elf_Internal_Sym *));
static boolean elf_m68k_finish_dynamic_sections
  PARAMS ((bfd *, struct bfd_link_info *));

static boolean elf32_m68k_set_private_flags
  PARAMS ((bfd *, flagword));
static boolean elf32_m68k_copy_private_bfd_data
  PARAMS ((bfd *, bfd *));
static boolean elf32_m68k_merge_private_bfd_data
  PARAMS ((bfd *, bfd *));
static boolean elf32_m68k_print_private_bfd_data
  PARAMS ((bfd *, PTR));

static reloc_howto_type howto_table[] = {
  HOWTO(R_68K_NONE,       0, 0, 0, false,0, complain_overflow_dont,     bfd_elf_generic_reloc, "R_68K_NONE",      false, 0, 0x00000000,false),
  HOWTO(R_68K_32,         0, 2,32, false,0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_32",        false, 0, 0xffffffff,false),
  HOWTO(R_68K_16,         0, 1,16, false,0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_16",        false, 0, 0x0000ffff,false),
  HOWTO(R_68K_8,          0, 0, 8, false,0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_8",         false, 0, 0x000000ff,false),
  HOWTO(R_68K_PC32,       0, 2,32, true, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_PC32",      false, 0, 0xffffffff,true),
  HOWTO(R_68K_PC16,       0, 1,16, true, 0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_PC16",      false, 0, 0x0000ffff,true),
  HOWTO(R_68K_PC8,        0, 0, 8, true, 0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_PC8",       false, 0, 0x000000ff,true),
  HOWTO(R_68K_GOT32,      0, 2,32, true, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_GOT32",     false, 0, 0xffffffff,true),
  HOWTO(R_68K_GOT16,      0, 1,16, true, 0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_GOT16",     false, 0, 0x0000ffff,true),
  HOWTO(R_68K_GOT8,       0, 0, 8, true, 0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_GOT8",      false, 0, 0x000000ff,true),
  HOWTO(R_68K_GOT32O,     0, 2,32, false,0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_GOT32O",    false, 0, 0xffffffff,false),
  HOWTO(R_68K_GOT16O,     0, 1,16, false,0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_GOT16O",    false, 0, 0x0000ffff,false),
  HOWTO(R_68K_GOT8O,      0, 0, 8, false,0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_GOT8O",     false, 0, 0x000000ff,false),
  HOWTO(R_68K_PLT32,      0, 2,32, true, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_PLT32",     false, 0, 0xffffffff,true),
  HOWTO(R_68K_PLT16,      0, 1,16, true, 0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_PLT16",     false, 0, 0x0000ffff,true),
  HOWTO(R_68K_PLT8,       0, 0, 8, true, 0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_PLT8",      false, 0, 0x000000ff,true),
  HOWTO(R_68K_PLT32O,     0, 2,32, false,0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_68K_PLT32O",    false, 0, 0xffffffff,false),
  HOWTO(R_68K_PLT16O,     0, 1,16, false,0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_PLT16O",    false, 0, 0x0000ffff,false),
  HOWTO(R_68K_PLT8O,      0, 0, 8, false,0, complain_overflow_signed,   bfd_elf_generic_reloc, "R_68K_PLT8O",     false, 0, 0x000000ff,false),
  HOWTO(R_68K_COPY,       0, 0, 0, false,0, complain_overflow_dont,     bfd_elf_generic_reloc, "R_68K_COPY",      false, 0, 0xffffffff,false),
  HOWTO(R_68K_GLOB_DAT,   0, 2,32, false,0, complain_overflow_dont,     bfd_elf_generic_reloc, "R_68K_GLOB_DAT",  false, 0, 0xffffffff,false),
  HOWTO(R_68K_JMP_SLOT,   0, 2,32, false,0, complain_overflow_dont,     bfd_elf_generic_reloc, "R_68K_JMP_SLOT",  false, 0, 0xffffffff,false),
  HOWTO(R_68K_RELATIVE,   0, 2,32, false,0, complain_overflow_dont,     bfd_elf_generic_reloc, "R_68K_RELATIVE",  false, 0, 0xffffffff,false),
  /* GNU extension to record C++ vtable hierarchy */
  HOWTO (R_68K_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_68K_GNU_VTINHERIT",	/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),
  /* GNU extension to record C++ vtable member usage */
  HOWTO (R_68K_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_68K_GNU_VTENTRY",	/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),
};

static void
rtype_to_howto (abfd, cache_ptr, dst)
     bfd *abfd ATTRIBUTE_UNUSED;
     arelent *cache_ptr;
     Elf_Internal_Rela *dst;
{
  BFD_ASSERT (ELF32_R_TYPE(dst->r_info) < (unsigned int) R_68K_max);
  cache_ptr->howto = &howto_table[ELF32_R_TYPE(dst->r_info)];
}

#define elf_info_to_howto rtype_to_howto

static const struct
{
  bfd_reloc_code_real_type bfd_val;
  int elf_val;
} reloc_map[] = {
  { BFD_RELOC_NONE, R_68K_NONE },
  { BFD_RELOC_32, R_68K_32 },
  { BFD_RELOC_16, R_68K_16 },
  { BFD_RELOC_8, R_68K_8 },
  { BFD_RELOC_32_PCREL, R_68K_PC32 },
  { BFD_RELOC_16_PCREL, R_68K_PC16 },
  { BFD_RELOC_8_PCREL, R_68K_PC8 },
  { BFD_RELOC_32_GOT_PCREL, R_68K_GOT32 },
  { BFD_RELOC_16_GOT_PCREL, R_68K_GOT16 },
  { BFD_RELOC_8_GOT_PCREL, R_68K_GOT8 },
  { BFD_RELOC_32_GOTOFF, R_68K_GOT32O },
  { BFD_RELOC_16_GOTOFF, R_68K_GOT16O },
  { BFD_RELOC_8_GOTOFF, R_68K_GOT8O },
  { BFD_RELOC_32_PLT_PCREL, R_68K_PLT32 },
  { BFD_RELOC_16_PLT_PCREL, R_68K_PLT16 },
  { BFD_RELOC_8_PLT_PCREL, R_68K_PLT8 },
  { BFD_RELOC_32_PLTOFF, R_68K_PLT32O },
  { BFD_RELOC_16_PLTOFF, R_68K_PLT16O },
  { BFD_RELOC_8_PLTOFF, R_68K_PLT8O },
  { BFD_RELOC_NONE, R_68K_COPY },
  { BFD_RELOC_68K_GLOB_DAT, R_68K_GLOB_DAT },
  { BFD_RELOC_68K_JMP_SLOT, R_68K_JMP_SLOT },
  { BFD_RELOC_68K_RELATIVE, R_68K_RELATIVE },
  { BFD_RELOC_CTOR, R_68K_32 },
  { BFD_RELOC_VTABLE_INHERIT, R_68K_GNU_VTINHERIT },
  { BFD_RELOC_VTABLE_ENTRY, R_68K_GNU_VTENTRY },
};

static reloc_howto_type *
reloc_type_lookup (abfd, code)
     bfd *abfd ATTRIBUTE_UNUSED;
     bfd_reloc_code_real_type code;
{
  unsigned int i;
  for (i = 0; i < sizeof (reloc_map) / sizeof (reloc_map[0]); i++)
    {
      if (reloc_map[i].bfd_val == code)
	return &howto_table[reloc_map[i].elf_val];
    }
  return 0;
}

#define bfd_elf32_bfd_reloc_type_lookup reloc_type_lookup
#define ELF_ARCH bfd_arch_m68k
/* end code generated by elf.el */

#define USE_RELA

/* Functions for the m68k 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 20

/* The first entry in a procedure linkage table looks like this.  See
   the SVR4 ABI m68k supplement to see how this works.  */

static const bfd_byte elf_m68k_plt0_entry[PLT_ENTRY_SIZE] =
{
  0x2f, 0x3b, 0x01, 0x70, /* move.l (%pc,addr),-(%sp) */
  0, 0, 0, 0,		  /* replaced with offset to .got + 4.  */
  0x4e, 0xfb, 0x01, 0x71, /* jmp ([%pc,addr]) */
  0, 0, 0, 0,		  /* replaced with offset to .got + 8.  */
  0, 0, 0, 0		  /* pad out to 20 bytes.  */
};

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

static const bfd_byte elf_m68k_plt_entry[PLT_ENTRY_SIZE] =
{
  0x4e, 0xfb, 0x01, 0x71, /* jmp ([%pc,symbol@GOTPC]) */
  0, 0, 0, 0,		  /* replaced with offset to symbol's .got entry.  */
  0x2f, 0x3c,		  /* move.l #offset,-(%sp) */
  0, 0, 0, 0,		  /* replaced with offset into relocation table.  */
  0x60, 0xff,		  /* bra.l .plt */
  0, 0, 0, 0		  /* replaced with offset to start of .plt.  */
};

#define CPU32_FLAG(abfd)  (elf_elfheader (abfd)->e_flags & EF_CPU32)

#define PLT_CPU32_ENTRY_SIZE 24
/* Procedure linkage table entries for the cpu32 */
static const bfd_byte elf_cpu32_plt0_entry[PLT_CPU32_ENTRY_SIZE] =
{
  0x2f, 0x3b, 0x01, 0x70, /* move.l (%pc,addr),-(%sp) */
  0, 0, 0, 0,             /* replaced with offset to .got + 4.  */
  0x22, 0x7b, 0x01, 0x70, /* moveal %pc@(0xc), %a1 */
  0, 0, 0, 0,             /* replace with offset to .got +8.  */
  0x4e, 0xd1,             /* jmp %a1@ */
  0, 0, 0, 0,             /* pad out to 24 bytes.  */
  0, 0
};

static const bfd_byte elf_cpu32_plt_entry[PLT_CPU32_ENTRY_SIZE] =
{
  0x22, 0x7b, 0x01, 0x70,  /* moveal %pc@(0xc), %a1 */
  0, 0, 0, 0,              /* replaced with offset to symbol's .got entry.  */
  0x4e, 0xd1,              /* jmp %a1@ */
  0x2f, 0x3c,              /* move.l #offset,-(%sp) */
  0, 0, 0, 0,              /* replaced with offset into relocation table.  */
  0x60, 0xff,              /* bra.l .plt */
  0, 0, 0, 0,              /* replaced with offset to start of .plt.  */
  0, 0
};

/* The m68k 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_m68k_pcrel_relocs_copied
{
  /* Next section.  */
  struct elf_m68k_pcrel_relocs_copied *next;
  /* A section in dynobj.  */
  asection *section;
  /* Number of relocs copied in this section.  */
  bfd_size_type count;
};

/* m68k ELF linker hash entry.  */

struct elf_m68k_link_hash_entry
{
  struct elf_link_hash_entry root;

  /* Number of PC relative relocs copied for this symbol.  */
  struct elf_m68k_pcrel_relocs_copied *pcrel_relocs_copied;
};

/* m68k ELF linker hash table.  */

struct elf_m68k_link_hash_table
{
  struct elf_link_hash_table root;
};

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

static boolean elf_m68k_discard_copies
  PARAMS ((struct elf_m68k_link_hash_entry *, PTR));

/* Traverse an m68k ELF linker hash table.  */

#define elf_m68k_link_hash_traverse(table, func, info)			\
  (elf_link_hash_traverse						\
   (&(table)->root,							\
    (boolean (*) PARAMS ((struct elf_link_hash_entry *, PTR))) (func),	\
    (info)))

/* Get the m68k ELF linker hash table from a link_info structure.  */

#define elf_m68k_hash_table(p) \
  ((struct elf_m68k_link_hash_table *) (p)->hash)

/* Create an entry in an m68k ELF linker hash table.  */

static struct bfd_hash_entry *
elf_m68k_link_hash_newfunc (entry, table, string)
     struct bfd_hash_entry *entry;
     struct bfd_hash_table *table;
     const char *string;
{
  struct elf_m68k_link_hash_entry *ret =
    (struct elf_m68k_link_hash_entry *) entry;

  /* Allocate the structure if it has not already been allocated by a
     subclass.  */
  if (ret == (struct elf_m68k_link_hash_entry *) NULL)
    ret = ((struct elf_m68k_link_hash_entry *)
	   bfd_hash_allocate (table,
			      sizeof (struct elf_m68k_link_hash_entry)));
  if (ret == (struct elf_m68k_link_hash_entry *) NULL)
    return (struct bfd_hash_entry *) ret;

  /* Call the allocation method of the superclass.  */
  ret = ((struct elf_m68k_link_hash_entry *)
	 _bfd_elf_link_hash_newfunc ((struct bfd_hash_entry *) ret,
				     table, string));
  if (ret != (struct elf_m68k_link_hash_entry *) NULL)
    {
      ret->pcrel_relocs_copied = NULL;
    }

  return (struct bfd_hash_entry *) ret;
}

/* Create an m68k ELF linker hash table.  */

static struct bfd_link_hash_table *
elf_m68k_link_hash_table_create (abfd)
     bfd *abfd;
{
  struct elf_m68k_link_hash_table *ret;

  ret = ((struct elf_m68k_link_hash_table *)
	 bfd_alloc (abfd, sizeof (struct elf_m68k_link_hash_table)));
  if (ret == (struct elf_m68k_link_hash_table *) NULL)
    return NULL;

  if (! _bfd_elf_link_hash_table_init (&ret->root, abfd,
				       elf_m68k_link_hash_newfunc))
    {
      bfd_release (abfd, ret);
      return NULL;
    }

  return &ret->root.root;
}

/* Keep m68k-specific flags in the ELF header */
static boolean
elf32_m68k_set_private_flags (abfd, flags)
     bfd *abfd;
     flagword flags;
{
  elf_elfheader (abfd)->e_flags = flags;
  elf_flags_init (abfd) = true;
  return true;
}

/* Copy m68k-specific data from one module to another */
static boolean
elf32_m68k_copy_private_bfd_data (ibfd, obfd)
     bfd *ibfd;
     bfd *obfd;
{
  flagword in_flags;

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

  in_flags = elf_elfheader (ibfd)->e_flags;

  elf_elfheader (obfd)->e_flags = in_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
elf32_m68k_merge_private_bfd_data (ibfd, obfd)
     bfd *ibfd;
     bfd *obfd;
{
  flagword out_flags;
  flagword in_flags;

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

  in_flags  = elf_elfheader (ibfd)->e_flags;
  out_flags = elf_elfheader (obfd)->e_flags;

  if (!elf_flags_init (obfd))
    {
      elf_flags_init (obfd) = true;
      elf_elfheader (obfd)->e_flags = in_flags;
    }

  return true;
}

/* Display the flags field */
static boolean
elf32_m68k_print_private_bfd_data (abfd, ptr)
     bfd *abfd;
     PTR ptr;
{
  FILE *file = (FILE *) ptr;

  BFD_ASSERT (abfd != NULL && ptr != NULL);

  /* Print normal ELF private data.  */
  _bfd_elf_print_private_bfd_data (abfd, ptr);

  /* Ignore init flag - it may not be set, despite the flags field containing valid data.  */

  /* xgettext:c-format */
  fprintf (file, _ ("private flags = %lx:"), elf_elfheader (abfd)->e_flags);

  if (elf_elfheader (abfd)->e_flags & EF_CPU32)
    fprintf (file, _ (" [cpu32]"));