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old-cross-binutils/bfd/elf32-i386.c
Alan Modra dd5724d523 Reference count .plt and .got on x86 for garbage collection code. Fix a 
couple of m68k and ppc bugs discovered while testing x86 gc.
2000-04-27 00:31:17 +00:00

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/* Intel 80386/80486-specific support for 32-bit ELF
Copyright 1993, 94-98, 1999 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),
EMPTY_HOWTO (11),
EMPTY_HOWTO (12),
EMPTY_HOWTO (13),
EMPTY_HOWTO (14),
EMPTY_HOWTO (15),
EMPTY_HOWTO (16),
EMPTY_HOWTO (17),
EMPTY_HOWTO (18),
EMPTY_HOWTO (19),
/* 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),
};
/* GNU extension to record C++ vtable hierarchy. */
static reloc_howto_type elf32_i386_vtinherit_howto =
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. */
static reloc_howto_type elf32_i386_vtentry_howto =
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);
#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[ (int)R_386_NONE ];
case BFD_RELOC_32:
TRACE ("BFD_RELOC_32");
return &elf_howto_table[ (int)R_386_32 ];
case BFD_RELOC_CTOR:
TRACE ("BFD_RELOC_CTOR");
return &elf_howto_table[ (int)R_386_32 ];
case BFD_RELOC_32_PCREL:
TRACE ("BFD_RELOC_PC32");
return &elf_howto_table[ (int)R_386_PC32 ];
case BFD_RELOC_386_GOT32:
TRACE ("BFD_RELOC_386_GOT32");
return &elf_howto_table[ (int)R_386_GOT32 ];
case BFD_RELOC_386_PLT32:
TRACE ("BFD_RELOC_386_PLT32");
return &elf_howto_table[ (int)R_386_PLT32 ];
case BFD_RELOC_386_COPY:
TRACE ("BFD_RELOC_386_COPY");
return &elf_howto_table[ (int)R_386_COPY ];
case BFD_RELOC_386_GLOB_DAT:
TRACE ("BFD_RELOC_386_GLOB_DAT");
return &elf_howto_table[ (int)R_386_GLOB_DAT ];
case BFD_RELOC_386_JUMP_SLOT:
TRACE ("BFD_RELOC_386_JUMP_SLOT");
return &elf_howto_table[ (int)R_386_JUMP_SLOT ];
case BFD_RELOC_386_RELATIVE:
TRACE ("BFD_RELOC_386_RELATIVE");
return &elf_howto_table[ (int)R_386_RELATIVE ];
case BFD_RELOC_386_GOTOFF:
TRACE ("BFD_RELOC_386_GOTOFF");
return &elf_howto_table[ (int)R_386_GOTOFF ];
case BFD_RELOC_386_GOTPC:
TRACE ("BFD_RELOC_386_GOTPC");
return &elf_howto_table[ (int)R_386_GOTPC ];
/* The remaining relocs are a GNU extension. */
case BFD_RELOC_16:
TRACE ("BFD_RELOC_16");
return &elf_howto_table[(int) R_386_16];
case BFD_RELOC_16_PCREL:
TRACE ("BFD_RELOC_16_PCREL");
return &elf_howto_table[(int) R_386_PC16];
case BFD_RELOC_8:
TRACE ("BFD_RELOC_8");
return &elf_howto_table[(int) R_386_8];
case BFD_RELOC_8_PCREL:
TRACE ("BFD_RELOC_8_PCREL");
return &elf_howto_table[(int) R_386_PC8];
case BFD_RELOC_VTABLE_INHERIT:
TRACE ("BFD_RELOC_VTABLE_INHERIT");
return &elf32_i386_vtinherit_howto;
case BFD_RELOC_VTABLE_ENTRY:
TRACE ("BFD_RELOC_VTABLE_ENTRY");
return &elf32_i386_vtentry_howto;
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;
{
enum elf_i386_reloc_type type;
type = (enum elf_i386_reloc_type) ELF32_R_TYPE (dst->r_info);
if (type == R_386_GNU_VTINHERIT)
cache_ptr->howto = &elf32_i386_vtinherit_howto;
else if (type == R_386_GNU_VTENTRY)
cache_ptr->howto = &elf32_i386_vtentry_howto;
else if (type < R_386_max
&& (type < FIRST_INVALID_RELOC || type > LAST_INVALID_RELOC))
cache_ptr->howto = &elf_howto_table[(int) type];
else
{
(*_bfd_error_handler) (_("%s: invalid relocation type %d"),
bfd_get_filename (abfd), (int) type);
cache_ptr->howto = &elf_howto_table[(int) R_386_NONE];
}
}
/* 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));
if (ret != (struct elf_i386_link_hash_entry *) NULL)
{
ret->pcrel_relocs_copied = NULL;
}
return (struct bfd_hash_entry *) ret;
}
/* Create an i386 ELF linker hash table. */
static struct bfd_link_hash_table *
elf_i386_link_hash_table_create (abfd)
bfd *abfd;
{
struct elf_i386_link_hash_table *ret;
ret = ((struct elf_i386_link_hash_table *)
bfd_alloc (abfd, sizeof (struct elf_i386_link_hash_table)));
if (ret == (struct elf_i386_link_hash_table *) NULL)
return NULL;
if (! _bfd_elf_link_hash_table_init (&ret->root, abfd,
elf_i386_link_hash_newfunc))
{
bfd_release (abfd, ret);
return NULL;
}
return &ret->root.root;
}
/* Look through the relocs for a section during the first phase, and
allocate space in the global offset table or procedure linkage
table. */
static boolean
elf_i386_check_relocs (abfd, info, sec, relocs)
bfd *abfd;
struct bfd_link_info *info;
asection *sec;
const Elf_Internal_Rela *relocs;
{
bfd *dynobj;
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry **sym_hashes;
bfd_signed_vma *local_got_refcounts;
const Elf_Internal_Rela *rel;
const Elf_Internal_Rela *rel_end;
asection *sgot;
asection *srelgot;
asection *sreloc;
if (info->relocateable)
return true;
dynobj = elf_hash_table (info)->dynobj;
symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
sym_hashes = elf_sym_hashes (abfd);
local_got_refcounts = elf_local_got_refcounts (abfd);
sgot = NULL;
srelgot = NULL;
sreloc = NULL;
rel_end = relocs + sec->reloc_count;
for (rel = relocs; rel < rel_end; rel++)
{
unsigned long r_symndx;
struct elf_link_hash_entry *h;
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];
/* Some relocs require a global offset table. */
if (dynobj == NULL)
{
switch (ELF32_R_TYPE (rel->r_info))
{
case R_386_GOT32:
case R_386_GOTOFF:
case R_386_GOTPC:
elf_hash_table (info)->dynobj = dynobj = abfd;
if (! _bfd_elf_create_got_section (dynobj, info))
return false;
break;
default:
break;
}
}
switch (ELF32_R_TYPE (rel->r_info))
{
case R_386_GOT32:
/* This symbol requires a global offset table entry. */
if (sgot == NULL)
{
sgot = bfd_get_section_by_name (dynobj, ".got");
BFD_ASSERT (sgot != NULL);
}
if (srelgot == NULL
&& (h != NULL || info->shared))
{
srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
if (srelgot == NULL)
{
srelgot = bfd_make_section (dynobj, ".rel.got");
if (srelgot == NULL
|| ! bfd_set_section_flags (dynobj, srelgot,
(SEC_ALLOC
| SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_IN_MEMORY
| SEC_LINKER_CREATED
| SEC_READONLY))
|| ! bfd_set_section_alignment (dynobj, srelgot, 2))
return false;
}
}
if (h != NULL)
{
if (h->got.refcount == -1)
{
h->got.refcount = 1;
/* Make sure this symbol is output as a dynamic symbol. */
if (h->dynindx == -1)
{
if (! bfd_elf32_link_record_dynamic_symbol (info, h))
return false;
}
sgot->_raw_size += 4;
srelgot->_raw_size += sizeof (Elf32_External_Rel);
}
else
h->got.refcount += 1;
}
else
{
/* This is a global offset table entry for a local symbol. */
if (local_got_refcounts == NULL)
{
size_t size;
size = symtab_hdr->sh_info * sizeof (bfd_signed_vma);
local_got_refcounts = ((bfd_signed_vma *)
bfd_alloc (abfd, size));
if (local_got_refcounts == NULL)
return false;
elf_local_got_refcounts (abfd) = local_got_refcounts;
memset (local_got_refcounts, -1, size);
}
if (local_got_refcounts[r_symndx] == -1)
{
local_got_refcounts[r_symndx] = 1;
sgot->_raw_size += 4;
if (info->shared)
{
/* If we are generating a shared object, we need to
output a R_386_RELATIVE reloc so that the dynamic
linker can adjust this GOT entry. */
srelgot->_raw_size += sizeof (Elf32_External_Rel);
}
}
else
local_got_refcounts[r_symndx] += 1;
}
break;
case R_386_PLT32:
/* This symbol requires a procedure linkage table entry. We
actually build the entry in adjust_dynamic_symbol,
because this might be a case of linking PIC code which is
never referenced by a dynamic object, in which case we
don't need to generate a procedure linkage table entry
after all. */
/* If this is a local symbol, we resolve it directly without
creating a procedure linkage table entry. */
if (h == NULL)
continue;
if (h->plt.refcount == -1)
{
h->plt.refcount = 1;
h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
}
else
h->plt.refcount += 1;
break;
case R_386_32:
case R_386_PC32:
if (h != NULL)
h->elf_link_hash_flags |= ELF_LINK_NON_GOT_REF;
/* If we are creating a shared library, and this is a reloc
against a global symbol, or a non PC relative reloc
against a local symbol, then we need to copy the reloc
into the shared library. However, if we are linking with
-Bsymbolic, we do not need to copy a reloc against a
global symbol which is defined in an object we are
including in the link (i.e., DEF_REGULAR is set). At
this point we have not seen all the input files, so it is
possible that DEF_REGULAR is not set now but will be set
later (it is never cleared). We account for that
possibility below by storing information in the
pcrel_relocs_copied field of the hash table entry. */
if (info->shared
&& (sec->flags & SEC_ALLOC) != 0
&& (ELF32_R_TYPE (rel->r_info) != R_386_PC32
|| (h != NULL
&& (! info->symbolic
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))))
{
/* When creating a shared object, we must copy these
reloc types into the output file. We create a reloc
section in dynobj and make room for this reloc. */
if (sreloc == NULL)
{
const char *name;
name = (bfd_elf_string_from_elf_section
(abfd,
elf_elfheader (abfd)->e_shstrndx,
elf_section_data (sec)->rel_hdr.sh_name));
if (name == NULL)
return false;
BFD_ASSERT (strncmp (name, ".rel", 4) == 0
&& strcmp (bfd_get_section_name (abfd, sec),
name + 4) == 0);
sreloc = bfd_get_section_by_name (dynobj, name);
if (sreloc == NULL)
{
flagword flags;
sreloc = bfd_make_section (dynobj, name);
flags = (SEC_HAS_CONTENTS | SEC_READONLY
| SEC_IN_MEMORY | SEC_LINKER_CREATED);
if ((sec->flags & SEC_ALLOC) != 0)
flags |= SEC_ALLOC | SEC_LOAD;
if (sreloc == NULL
|| ! bfd_set_section_flags (dynobj, sreloc, flags)
|| ! bfd_set_section_alignment (dynobj, sreloc, 2))
return false;
}
}
sreloc->_raw_size += sizeof (Elf32_External_Rel);
/* If we are linking with -Bsymbolic, and this is a
global symbol, we count the number of PC relative
relocations we have entered for this symbol, so that
we can discard them again if the symbol is later
defined by a regular object. Note that this function
is only called if we are using an elf_i386 linker
hash table, which means that h is really a pointer to
an elf_i386_link_hash_entry. */
if (h != NULL && info->symbolic
&& ELF32_R_TYPE (rel->r_info) == R_386_PC32)
{
struct elf_i386_link_hash_entry *eh;
struct elf_i386_pcrel_relocs_copied *p;
eh = (struct elf_i386_link_hash_entry *) h;
for (p = eh->pcrel_relocs_copied; p != NULL; p = p->next)
if (p->section == sreloc)
break;
if (p == NULL)
{
p = ((struct elf_i386_pcrel_relocs_copied *)
bfd_alloc (dynobj, sizeof *p));
if (p == NULL)
return false;
p->next = eh->pcrel_relocs_copied;
eh->pcrel_relocs_copied = p;
p->section = sreloc;
p->count = 0;
}
++p->count;
}
}
break;
/* This relocation describes the C++ object vtable hierarchy.
Reconstruct it for later use during GC. */
case R_386_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_386_GNU_VTENTRY:
if (!_bfd_elf32_gc_record_vtentry (abfd, sec, h, rel->r_offset))
return false;
break;
default:
break;
}
}
return true;
}
/* Return the section that should be marked against GC for a given
relocation. */
static asection *
elf_i386_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_386_GNU_VTINHERIT:
case R_386_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
elf_i386_gc_sweep_hook (abfd, info, sec, relocs)
bfd *abfd;
struct bfd_link_info *info ATTRIBUTE_UNUSED;
asection *sec;
const Elf_Internal_Rela *relocs;
{
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry **sym_hashes;
bfd_signed_vma *local_got_refcounts;
const Elf_Internal_Rela *rel, *relend;
unsigned long r_symndx;
struct elf_link_hash_entry *h;
bfd *dynobj;
asection *sgot;
asection *srelgot;
symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
sym_hashes = elf_sym_hashes (abfd);
local_got_refcounts = elf_local_got_refcounts (abfd);
dynobj = elf_hash_table (info)->dynobj;
if (dynobj == NULL)
return true;
sgot = bfd_get_section_by_name (dynobj, ".got");
srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
relend = relocs + sec->reloc_count;
for (rel = relocs; rel < relend; rel++)
switch (ELF32_R_TYPE (rel->r_info))
{
case R_386_GOT32:
case R_386_GOTOFF:
case R_386_GOTPC:
r_symndx = ELF32_R_SYM (rel->r_info);
if (r_symndx >= symtab_hdr->sh_info)
{
h = sym_hashes[r_symndx - symtab_hdr->sh_info];
if (h->got.refcount > 0)
{
h->got.refcount -= 1;
if (h->got.refcount == 0)
{
sgot->_raw_size -= 4;
srelgot->_raw_size -= sizeof (Elf32_External_Rel);
}
}
}
else if (local_got_refcounts != NULL)
{
if (local_got_refcounts[r_symndx] > 0)
{
local_got_refcounts[r_symndx] -= 1;
if (local_got_refcounts[r_symndx] == 0)
{
sgot->_raw_size -= 4;
if (info->shared)
srelgot->_raw_size -= sizeof (Elf32_External_Rel);
}
}
}
break;
case R_386_PLT32:
r_symndx = ELF32_R_SYM (rel->r_info);
if (r_symndx >= symtab_hdr->sh_info)
{
h = sym_hashes[r_symndx - symtab_hdr->sh_info];
if (h->plt.refcount > 0)
h->plt.refcount -= 1;
}
break;
default:
break;
}
return true;
}
/* Adjust a symbol defined by a dynamic object and referenced by a
regular object. The current definition is in some section of the
dynamic object, but we're not including those sections. We have to
change the definition to something the rest of the link can
understand. */
static boolean
elf_i386_adjust_dynamic_symbol (info, h)
struct bfd_link_info *info;
struct elf_link_hash_entry *h;
{
bfd *dynobj;
asection *s;
unsigned int power_of_two;
dynobj = elf_hash_table (info)->dynobj;
/* Make sure we know what is going on here. */
BFD_ASSERT (dynobj != NULL
&& ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT)
|| h->weakdef != NULL
|| ((h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_DYNAMIC) != 0
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_REF_REGULAR) != 0
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0)));
/* If this is a function, put it in the procedure linkage table. We
will fill in the contents of the procedure linkage table later,
when we know the address of the .got section. */
if (h->type == STT_FUNC
|| (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0)
{
if ((! info->shared
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
&& (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) == 0)
|| (info->shared && h->plt.refcount <= 0))
{
/* This case can occur if we saw a PLT32 reloc in an input
file, but the symbol was never referred to by a dynamic
object, or if all references were garbage collected. In
such a case, we don't actually need to build a procedure
linkage table, and we can just do a PC32 reloc instead. */
h->plt.offset = (bfd_vma) -1;
h->elf_link_hash_flags &= ~ELF_LINK_HASH_NEEDS_PLT;
return true;
}
/* Make sure this symbol is output as a dynamic symbol. */
if (h->dynindx == -1)
{
if (! bfd_elf32_link_record_dynamic_symbol (info, h))
return false;
}
s = bfd_get_section_by_name (dynobj, ".plt");
BFD_ASSERT (s != NULL);
/* If this is the first .plt entry, make room for the special
first entry. */
if (s->_raw_size == 0)
s->_raw_size += PLT_ENTRY_SIZE;
/* If this symbol is not defined in a regular file, and we are
not generating a shared library, then set the symbol to this
location in the .plt. This is required to make function
pointers compare as equal between the normal executable and
the shared library. */
if (! info->shared
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
{
h->root.u.def.section = s;
h->root.u.def.value = s->_raw_size;
}
h->plt.offset = s->_raw_size;
/* Make room for this entry. */
s->_raw_size += PLT_ENTRY_SIZE;
/* We also need to make an entry in the .got.plt section, which
will be placed in the .got section by the linker script. */
s = bfd_get_section_by_name (dynobj, ".got.plt");
BFD_ASSERT (s != NULL);
s->_raw_size += 4;
/* We also need to make an entry in the .rel.plt section. */
s = bfd_get_section_by_name (dynobj, ".rel.plt");
BFD_ASSERT (s != NULL);
s->_raw_size += sizeof (Elf32_External_Rel);
return true;
}
/* If this is a weak symbol, and there is a real definition, the
processor independent code will have arranged for us to see the
real definition first, and we can just use the same value. */
if (h->weakdef != NULL)
{
BFD_ASSERT (h->weakdef->root.type == bfd_link_hash_defined
|| h->weakdef->root.type == bfd_link_hash_defweak);
h->root.u.def.section = h->weakdef->root.u.def.section;
h->root.u.def.value = h->weakdef->root.u.def.value;
return true;
}
/* This is a reference to a symbol defined by a dynamic object which
is not a function. */
/* If we are creating a shared library, we must presume that the
only references to the symbol are via the global offset table.
For such cases we need not do anything here; the relocations will
be handled correctly by relocate_section. */
if (info->shared)
return true;
/* If there are no references to this symbol that do not use the
GOT, we don't need to generate a copy reloc. */
if ((h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0)
return true;
/* We must allocate the symbol in our .dynbss section, which will
become part of the .bss section of the executable. There will be
an entry for this symbol in the .dynsym section. The dynamic
object will contain position independent code, so all references
from the dynamic object to this symbol will go through the global
offset table. The dynamic linker will use the .dynsym entry to
determine the address it must put in the global offset table, so
both the dynamic object and the regular object will refer to the
same memory location for the variable. */
s = bfd_get_section_by_name (dynobj, ".dynbss");
BFD_ASSERT (s != NULL);
/* We must generate a R_386_COPY reloc to tell the dynamic linker to
copy the initial value out of the dynamic object and into the
runtime process image. We need to remember the offset into the
.rel.bss section we are going to use. */
if ((h->root.u.def.section->flags & SEC_ALLOC) != 0)
{
asection *srel;
srel = bfd_get_section_by_name (dynobj, ".rel.bss");
BFD_ASSERT (srel != NULL);
srel->_raw_size += sizeof (Elf32_External_Rel);
h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_COPY;
}
/* We need to figure out the alignment required for this symbol. I
have no idea how ELF linkers handle this. */
power_of_two = bfd_log2 (h->size);
if (power_of_two > 3)
power_of_two = 3;
/* Apply the required alignment. */
s->_raw_size = BFD_ALIGN (s->_raw_size,
(bfd_size_type) (1 << power_of_two));
if (power_of_two > bfd_get_section_alignment (dynobj, s))
{
if (! bfd_set_section_alignment (dynobj, s, power_of_two))
return false;
}
/* Define the symbol as being at this point in the section. */
h->root.u.def.section = s;
h->root.u.def.value = s->_raw_size;
/* Increment the section size to make room for the symbol. */
s->_raw_size += h->size;
return true;
}
/* Set the sizes of the dynamic sections. */
static boolean
elf_i386_size_dynamic_sections (output_bfd, info)
bfd *output_bfd;
struct bfd_link_info *info;
{
bfd *dynobj;
asection *s;
boolean plt;
boolean relocs;
boolean reltext;
dynobj = elf_hash_table (info)->dynobj;
BFD_ASSERT (dynobj != NULL);
if (elf_hash_table (info)->dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
if (! info->shared)
{
s = bfd_get_section_by_name (dynobj, ".interp");
BFD_ASSERT (s != NULL);
s->_raw_size = sizeof ELF_DYNAMIC_INTERPRETER;
s->contents = (unsigned char *) ELF_DYNAMIC_INTERPRETER;
}
}
else
{
/* We may have created entries in the .rel.got section.
However, if we are not creating the dynamic sections, we will
not actually use these entries. Reset the size of .rel.got,
which will cause it to get stripped from the output file
below. */
s = bfd_get_section_by_name (dynobj, ".rel.got");
if (s != NULL)
s->_raw_size = 0;
}
/* If this is a -Bsymbolic shared link, then we need to discard all
PC relative relocs against symbols defined in a regular object.
We allocated space for them in the check_relocs routine, but we
will not fill them in in the relocate_section routine. */
if (info->shared && info->symbolic)
elf_i386_link_hash_traverse (elf_i386_hash_table (info),
elf_i386_discard_copies,
(PTR) NULL);
/* The check_relocs and adjust_dynamic_symbol entry points have
determined the sizes of the various dynamic sections. Allocate
memory for them. */
plt = false;
relocs = false;
reltext = false;
for (s = dynobj->sections; s != NULL; s = s->next)
{
const char *name;
boolean strip;
if ((s->flags & SEC_LINKER_CREATED) == 0)
continue;
/* It's OK to base decisions on the section name, because none
of the dynobj section names depend upon the input files. */
name = bfd_get_section_name (dynobj, s);
strip = false;
if (strcmp (name, ".plt") == 0)
{
if (s->_raw_size == 0)
{
/* Strip this section if we don't need it; see the
comment below. */
strip = true;
}
else
{
/* Remember whether there is a PLT. */
plt = true;
}
}
else if (strncmp (name, ".rel", 4) == 0)
{
if (s->_raw_size == 0)
{
/* If we don't need this section, strip it from the
output file. This is mostly to handle .rel.bss and
.rel.plt. We must create both sections in
create_dynamic_sections, because they must be created
before the linker maps input sections to output
sections. The linker does that before
adjust_dynamic_symbol is called, and it is that
function which decides whether anything needs to go
into these sections. */
strip = true;
}
else
{
asection *target;
/* Remember whether there are any reloc sections other
than .rel.plt. */
if (strcmp (name, ".rel.plt") != 0)
{
const char *outname;
relocs = true;
/* If this relocation section applies to a read only
section, then we probably need a DT_TEXTREL
entry. The entries in the .rel.plt section
really apply to the .got section, which we
created ourselves and so know is not readonly. */
outname = bfd_get_section_name (output_bfd,
s->output_section);
target = bfd_get_section_by_name (output_bfd, outname + 4);
if (target != NULL
&& (target->flags & SEC_READONLY) != 0
&& (target->flags & SEC_ALLOC) != 0)
reltext = true;
}
/* We use the reloc_count field as a counter if we need
to copy relocs into the output file. */
s->reloc_count = 0;
}
}
else if (strncmp (name, ".got", 4) != 0)
{
/* It's not one of our sections, so don't allocate space. */
continue;
}
if (strip)
{
_bfd_strip_section_from_output (info, s);
continue;
}
/* Allocate memory for the section contents. */
s->contents = (bfd_byte *) bfd_alloc (dynobj, s->_raw_size);
if (s->contents == NULL && s->_raw_size != 0)
return false;
}
if (elf_hash_table (info)->dynamic_sections_created)
{
/* Add some entries to the .dynamic section. We fill in the
values later, in elf_i386_finish_dynamic_sections, but we
must add the entries now so that we get the correct size for
the .dynamic section. The DT_DEBUG entry is filled in by the
dynamic linker and used by the debugger. */
if (! info->shared)
{
if (! bfd_elf32_add_dynamic_entry (info, DT_DEBUG, 0))
return false;
}
if (plt)
{
if (! bfd_elf32_add_dynamic_entry (info, DT_PLTGOT, 0)
|| ! bfd_elf32_add_dynamic_entry (info, DT_PLTRELSZ, 0)
|| ! bfd_elf32_add_dynamic_entry (info, DT_PLTREL, DT_REL)
|| ! bfd_elf32_add_dynamic_entry (info, DT_JMPREL, 0))
return false;
}
if (relocs)
{
if (! bfd_elf32_add_dynamic_entry (info, DT_REL, 0)
|| ! bfd_elf32_add_dynamic_entry (info, DT_RELSZ, 0)
|| ! bfd_elf32_add_dynamic_entry (info, DT_RELENT,
sizeof (Elf32_External_Rel)))
return false;
}
if (reltext)
{
if (! bfd_elf32_add_dynamic_entry (info, DT_TEXTREL, 0))
return false;
}
}
return true;
}
/* This function is called via elf_i386_link_hash_traverse if we are
creating a shared object with -Bsymbolic. It discards the space
allocated to copy PC relative relocs against symbols which are
defined in regular objects. We allocated space for them in the
check_relocs routine, but we won't fill them in in the
relocate_section routine. */
/*ARGSUSED*/
static boolean
elf_i386_discard_copies (h, ignore)
struct elf_i386_link_hash_entry *h;
PTR ignore ATTRIBUTE_UNUSED;
{
struct elf_i386_pcrel_relocs_copied *s;
/* We only discard relocs for symbols defined in a regular object. */
if ((h->root.elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
return true;
for (s = h->pcrel_relocs_copied; s != NULL; s = s->next)
s->section->_raw_size -= s->count * sizeof (Elf32_External_Rel);
return true;
}
/* Relocate an i386 ELF section. */
static boolean
elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
contents, relocs, local_syms, local_sections)
bfd *output_bfd;
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;
{
bfd *dynobj;
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry **sym_hashes;
bfd_vma *local_got_offsets;
asection *sgot;
asection *splt;
asection *sreloc;
Elf_Internal_Rela *rel;
Elf_Internal_Rela *relend;
dynobj = elf_hash_table (info)->dynobj;
symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
sym_hashes = elf_sym_hashes (input_bfd);
local_got_offsets = elf_local_got_offsets (input_bfd);
sreloc = NULL;
splt = NULL;
sgot = NULL;
if (dynobj != NULL)
{
splt = bfd_get_section_by_name (dynobj, ".plt");
sgot = bfd_get_section_by_name (dynobj, ".got");
}
rel = relocs;
relend = relocs + input_section->reloc_count;
for (; rel < relend; rel++)
{
int r_type;
reloc_howto_type *howto;
unsigned long r_symndx;
struct elf_link_hash_entry *h;
Elf_Internal_Sym *sym;
asection *sec;
bfd_vma relocation;
bfd_reloc_status_type r;
r_type = ELF32_R_TYPE (rel->r_info);
if (r_type == R_386_GNU_VTINHERIT
|| r_type == R_386_GNU_VTENTRY)
continue;
if (r_type < 0
|| r_type >= (int) R_386_max
|| (r_type >= (int) FIRST_INVALID_RELOC
&& r_type <= (int) LAST_INVALID_RELOC))
{
bfd_set_error (bfd_error_bad_value);
return false;
}
howto = elf_howto_table + r_type;
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)
{
bfd_vma val;
sec = local_sections[r_symndx];
val = bfd_get_32 (input_bfd, contents + rel->r_offset);
val += sec->output_offset + sym->st_value;
bfd_put_32 (input_bfd, val, contents + rel->r_offset);
}
}
continue;
}
/* This is a final link. */
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);
}
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;
if (h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
{
sec = h->root.u.def.section;
if (r_type == R_386_GOTPC
|| (r_type == R_386_PLT32
&& splt != NULL
&& h->plt.offset != (bfd_vma) -1)
|| (r_type == R_386_GOT32
&& elf_hash_table (info)->dynamic_sections_created
&& (! info->shared
|| (! info->symbolic && h->dynindx != -1)
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))
|| (info->shared
&& ((! info->symbolic && h->dynindx != -1)
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0)
&& (r_type == R_386_32
|| r_type == R_386_PC32)
&& ((input_section->flags & SEC_ALLOC) != 0
/* DWARF will emit R_386_32 relocations in its
sections against symbols defined externally
in shared libraries. We can't do anything
with them here. */
|| ((input_section->flags & SEC_DEBUGGING) != 0
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_DYNAMIC) != 0))))
{
/* In these cases, we don't need the relocation
value. We check specially because in some
obscure cases sec->output_section will be NULL. */
relocation = 0;
}
else if (sec->output_section == NULL)
{
(*_bfd_error_handler)
(_("%s: warning: unresolvable relocation against symbol `%s' from %s section"),
bfd_get_filename (input_bfd), h->root.root.string,
bfd_get_section_name (input_bfd, input_section));
relocation = 0;
}
else
relocation = (h->root.u.def.value
+ sec->output_section->vma
+ sec->output_offset);
}
else if (h->root.type == bfd_link_hash_undefweak)
relocation = 0;
else if (info->shared && !info->symbolic && !info->no_undefined)
relocation = 0;
else
{
if (! ((*info->callbacks->undefined_symbol)
(info, h->root.root.string, input_bfd,
input_section, rel->r_offset,
(!info->shared || info->no_undefined))))
return false;
relocation = 0;
}
}
switch (r_type)
{
case R_386_GOT32:
/* Relocation is to the entry for this symbol in the global
offset table. */
BFD_ASSERT (sgot != NULL);
if (h != NULL)
{
bfd_vma off;
off = h->got.offset;
BFD_ASSERT (off != (bfd_vma) -1);
if (! elf_hash_table (info)->dynamic_sections_created
|| (info->shared
&& (info->symbolic || h->dynindx == -1)
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR)))
{
/* This is actually a static link, or it is a
-Bsymbolic link and the symbol is defined
locally, or the symbol was forced to be local
because of a version file. We must initialize
this entry in the global offset table. Since the
offset must always be a multiple of 4, we use the
least significant bit to record whether we have
initialized it already.
When doing a dynamic link, we create a .rel.got
relocation entry to initialize the value. This
is done in the finish_dynamic_symbol routine. */
if ((off & 1) != 0)
off &= ~1;
else
{
bfd_put_32 (output_bfd, relocation,
sgot->contents + off);
h->got.offset |= 1;
}
}
relocation = sgot->output_offset + off;
}
else
{
bfd_vma off;
BFD_ASSERT (local_got_offsets != NULL
&& local_got_offsets[r_symndx] != (bfd_vma) -1);
off = local_got_offsets[r_symndx];
/* The offset must always be a multiple of 4. We use
the least significant bit to record whether we have
already generated the necessary reloc. */
if ((off & 1) != 0)
off &= ~1;
else
{
bfd_put_32 (output_bfd, relocation, sgot->contents + off);
if (info->shared)
{
asection *srelgot;
Elf_Internal_Rel outrel;
srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
BFD_ASSERT (srelgot != NULL);
outrel.r_offset = (sgot->output_section->vma
+ sgot->output_offset
+ off);
outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
bfd_elf32_swap_reloc_out (output_bfd, &outrel,
(((Elf32_External_Rel *)
srelgot->contents)
+ srelgot->reloc_count));
++srelgot->reloc_count;
}
local_got_offsets[r_symndx] |= 1;
}
relocation = sgot->output_offset + off;
}
break;
case R_386_GOTOFF:
/* Relocation is relative to the start of the global offset
table. */
if (sgot == NULL)
{
sgot = bfd_get_section_by_name (dynobj, ".got");
BFD_ASSERT (sgot != NULL);
}
/* Note that sgot->output_offset is not involved in this
calculation. We always want the start of .got. If we
defined _GLOBAL_OFFSET_TABLE in a different way, as is
permitted by the ABI, we might have to change this
calculation. */
relocation -= sgot->output_section->vma;
break;
case R_386_GOTPC:
/* Use global offset table as symbol value. */
if (sgot == NULL)
{
sgot = bfd_get_section_by_name (dynobj, ".got");
BFD_ASSERT (sgot != NULL);
}
relocation = sgot->output_section->vma;
break;
case R_386_PLT32:
/* Relocation is to the entry for this symbol in the
procedure linkage table. */
/* Resolve a PLT32 reloc against a local symbol directly,
without using the procedure linkage table. */
if (h == NULL)
break;
if (h->plt.offset == (bfd_vma) -1
|| splt == NULL)
{
/* We didn't make a PLT entry for this symbol. This
happens when statically linking PIC code, or when
using -Bsymbolic. */
break;
}
relocation = (splt->output_section->vma
+ splt->output_offset
+ h->plt.offset);
break;
case R_386_32:
case R_386_PC32:
if (info->shared
&& (input_section->flags & SEC_ALLOC) != 0
&& (r_type != R_386_PC32
|| (h != NULL
&& h->dynindx != -1
&& (! info->symbolic
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))))
{
Elf_Internal_Rel outrel;
boolean skip, relocate;
/* When generating a shared object, these relocations
are copied into the output file to be resolved at run
time. */
if (sreloc == NULL)
{
const char *name;
name = (bfd_elf_string_from_elf_section
(input_bfd,
elf_elfheader (input_bfd)->e_shstrndx,
elf_section_data (input_section)->rel_hdr.sh_name));
if (name == NULL)
return false;
BFD_ASSERT (strncmp (name, ".rel", 4) == 0
&& strcmp (bfd_get_section_name (input_bfd,
input_section),
name + 4) == 0);
sreloc = bfd_get_section_by_name (dynobj, name);
BFD_ASSERT (sreloc != NULL);
}
skip = false;
if (elf_section_data (input_section)->stab_info == NULL)
outrel.r_offset = rel->r_offset;
else
{
bfd_vma off;
off = (_bfd_stab_section_offset
(output_bfd, &elf_hash_table (info)->stab_info,
input_section,
&elf_section_data (input_section)->stab_info,
rel->r_offset));
if (off == (bfd_vma) -1)
skip = true;
outrel.r_offset = off;
}
outrel.r_offset += (input_section->output_section->vma
+ input_section->output_offset);
if (skip)
{
memset (&outrel, 0, sizeof outrel);
relocate = false;
}
else if (r_type == R_386_PC32)
{
BFD_ASSERT (h != NULL && h->dynindx != -1);
relocate = false;
outrel.r_info = ELF32_R_INFO (h->dynindx, R_386_PC32);
}
else
{
/* h->dynindx may be -1 if this symbol was marked to
become local. */
if (h == NULL
|| ((info->symbolic || h->dynindx == -1)
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) != 0))
{
relocate = true;
outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
}
else
{
BFD_ASSERT (h->dynindx != -1);
relocate = false;
outrel.r_info = ELF32_R_INFO (h->dynindx, R_386_32);
}
}
bfd_elf32_swap_reloc_out (output_bfd, &outrel,
(((Elf32_External_Rel *)
sreloc->contents)
+ sreloc->reloc_count));
++sreloc->reloc_count;
/* If this reloc is against an external symbol, we do
not want to fiddle with the addend. Otherwise, we
need to include the symbol value so that it becomes
an addend for the dynamic reloc. */
if (! relocate)
continue;
}
break;
default:
break;
}
r = _bfd_final_link_relocate (howto, input_bfd, input_section,
contents, rel->r_offset,
relocation, (bfd_vma) 0);
if (r != bfd_reloc_ok)
{
switch (r)
{
default:
case bfd_reloc_outofrange:
abort ();
case bfd_reloc_overflow:
{
const char *name;
if (h != NULL)
name = h->root.root.string;
else
{
name = bfd_elf_string_from_elf_section (input_bfd,
symtab_hdr->sh_link,
sym->st_name);
if (name == NULL)
return false;
if (*name == '\0')
name = bfd_section_name (input_bfd, sec);
}
if (! ((*info->callbacks->reloc_overflow)
(info, name, howto->name, (bfd_vma) 0,
input_bfd, input_section, rel->r_offset)))
return false;
}
break;
}
}
}
return true;
}
/* Finish up dynamic symbol handling. We set the contents of various
dynamic sections here. */
static boolean
elf_i386_finish_dynamic_symbol (output_bfd, info, h, sym)
bfd *output_bfd;
struct bfd_link_info *info;
struct elf_link_hash_entry *h;
Elf_Internal_Sym *sym;
{
bfd *dynobj;
dynobj = elf_hash_table (info)->dynobj;
if (h->plt.offset != (bfd_vma) -1)
{
asection *splt;
asection *sgot;
asection *srel;
bfd_vma plt_index;
bfd_vma got_offset;
Elf_Internal_Rel rel;
/* This symbol has an entry in the procedure linkage table. Set
it up. */
BFD_ASSERT (h->dynindx != -1);
splt = bfd_get_section_by_name (dynobj, ".plt");
sgot = bfd_get_section_by_name (dynobj, ".got.plt");
srel = bfd_get_section_by_name (dynobj, ".rel.plt");
BFD_ASSERT (splt != NULL && sgot != NULL && srel != NULL);
/* Get the index in the procedure linkage table which
corresponds to this symbol. This is the index of this symbol
in all the symbols for which we are making plt entries. The
first entry in the procedure linkage table is reserved. */
plt_index = h->plt.offset / PLT_ENTRY_SIZE - 1;
/* Get the offset into the .got table of the entry that
corresponds to this function. Each .got entry is 4 bytes.
The first three are reserved. */
got_offset = (plt_index + 3) * 4;
/* Fill in the entry in the procedure linkage table. */
if (! info->shared)
{
memcpy (splt->contents + h->plt.offset, elf_i386_plt_entry,
PLT_ENTRY_SIZE);
bfd_put_32 (output_bfd,
(sgot->output_section->vma
+ sgot->output_offset
+ got_offset),
splt->contents + h->plt.offset + 2);
}
else
{
memcpy (splt->contents + h->plt.offset, elf_i386_pic_plt_entry,
PLT_ENTRY_SIZE);
bfd_put_32 (output_bfd, got_offset,
splt->contents + h->plt.offset + 2);
}
bfd_put_32 (output_bfd, plt_index * sizeof (Elf32_External_Rel),
splt->contents + h->plt.offset + 7);
bfd_put_32 (output_bfd, - (h->plt.offset + PLT_ENTRY_SIZE),
splt->contents + h->plt.offset + 12);
/* Fill in the entry in the global offset table. */
bfd_put_32 (output_bfd,
(splt->output_section->vma
+ splt->output_offset
+ h->plt.offset
+ 6),
sgot->contents + got_offset);
/* Fill in the entry in the .rel.plt section. */
rel.r_offset = (sgot->output_section->vma
+ sgot->output_offset
+ got_offset);
rel.r_info = ELF32_R_INFO (h->dynindx, R_386_JUMP_SLOT);
bfd_elf32_swap_reloc_out (output_bfd, &rel,
((Elf32_External_Rel *) srel->contents
+ plt_index));
if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
{
/* Mark the symbol as undefined, rather than as defined in
the .plt section. Leave the value alone. */
sym->st_shndx = SHN_UNDEF;
}
}
if (h->got.offset != (bfd_vma) -1)
{
asection *sgot;
asection *srel;
Elf_Internal_Rel rel;
/* This symbol has an entry in the global offset table. Set it
up. */
sgot = bfd_get_section_by_name (dynobj, ".got");
srel = bfd_get_section_by_name (dynobj, ".rel.got");
BFD_ASSERT (sgot != NULL && srel != NULL);
rel.r_offset = (sgot->output_section->vma
+ sgot->output_offset
+ (h->got.offset &~ 1));
/* If this is a static link, or it is a -Bsymbolic link and the
symbol is defined locally or was forced to be local because
of a version file, we just want to emit a RELATIVE reloc.
The entry in the global offset table will already have been
initialized in the relocate_section function. */
if (! elf_hash_table (info)->dynamic_sections_created
|| (info->shared
&& (info->symbolic || h->dynindx == -1)
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR)))
{
rel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
}
else
{
BFD_ASSERT((h->got.offset & 1) == 0);
bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + h->got.offset);
rel.r_info = ELF32_R_INFO (h->dynindx, R_386_GLOB_DAT);
}
bfd_elf32_swap_reloc_out (output_bfd, &rel,
((Elf32_External_Rel *) srel->contents
+ srel->reloc_count));
++srel->reloc_count;
}
if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_COPY) != 0)
{
asection *s;
Elf_Internal_Rel rel;
/* This symbol needs a copy reloc. Set it up. */
BFD_ASSERT (h->dynindx != -1
&& (h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak));
s = bfd_get_section_by_name (h->root.u.def.section->owner,
".rel.bss");
BFD_ASSERT (s != NULL);
rel.r_offset = (h->root.u.def.value
+ h->root.u.def.section->output_section->vma
+ h->root.u.def.section->output_offset);
rel.r_info = ELF32_R_INFO (h->dynindx, R_386_COPY);
bfd_elf32_swap_reloc_out (output_bfd, &rel,
((Elf32_External_Rel *) s->contents
+ s->reloc_count));
++s->reloc_count;
}
/* Mark _DYNAMIC and _GLOBAL_OFFSET_TABLE_ as absolute. */
if (strcmp (h->root.root.string, "_DYNAMIC") == 0
|| strcmp (h->root.root.string, "_GLOBAL_OFFSET_TABLE_") == 0)
sym->st_shndx = SHN_ABS;
return true;
}
/* Finish up the dynamic sections. */
static boolean
elf_i386_finish_dynamic_sections (output_bfd, info)
bfd *output_bfd;
struct bfd_link_info *info;
{
bfd *dynobj;
asection *sgot;
asection *sdyn;
dynobj = elf_hash_table (info)->dynobj;
sgot = bfd_get_section_by_name (dynobj, ".got.plt");
BFD_ASSERT (sgot != NULL);
sdyn = bfd_get_section_by_name (dynobj, ".dynamic");
if (elf_hash_table (info)->dynamic_sections_created)
{
asection *splt;
Elf32_External_Dyn *dyncon, *dynconend;
BFD_ASSERT (sdyn != NULL);
dyncon = (Elf32_External_Dyn *) sdyn->contents;
dynconend = (Elf32_External_Dyn *) (sdyn->contents + sdyn->_raw_size);
for (; dyncon < dynconend; dyncon++)
{
Elf_Internal_Dyn dyn;
const char *name;
asection *s;
bfd_elf32_swap_dyn_in (dynobj, dyncon, &dyn);
switch (dyn.d_tag)
{
default:
break;
case DT_PLTGOT:
name = ".got";
goto get_vma;
case DT_JMPREL:
name = ".rel.plt";
get_vma:
s = bfd_get_section_by_name (output_bfd, name);
BFD_ASSERT (s != NULL);
dyn.d_un.d_ptr = s->vma;
bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
break;
case DT_PLTRELSZ:
s = bfd_get_section_by_name (output_bfd, ".rel.plt");
BFD_ASSERT (s != NULL);
if (s->_cooked_size != 0)
dyn.d_un.d_val = s->_cooked_size;
else
dyn.d_un.d_val = s->_raw_size;
bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
break;
case DT_RELSZ:
/* My reading of the SVR4 ABI indicates that the
procedure linkage table relocs (DT_JMPREL) should be
included in the overall relocs (DT_REL). This is
what Solaris does. However, UnixWare can not handle
that case. Therefore, we override the DT_RELSZ entry
here to make it not include the JMPREL relocs. Since
the linker script arranges for .rel.plt to follow all
other relocation sections, we don't have to worry
about changing the DT_REL entry. */
s = bfd_get_section_by_name (output_bfd, ".rel.plt");
if (s != NULL)
{
if (s->_cooked_size != 0)
dyn.d_un.d_val -= s->_cooked_size;
else
dyn.d_un.d_val -= s->_raw_size;
}
bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
break;
}
}
/* Fill in the first entry in the procedure linkage table. */
splt = bfd_get_section_by_name (dynobj, ".plt");
if (splt && splt->_raw_size > 0)
{
if (info->shared)
memcpy (splt->contents, elf_i386_pic_plt0_entry, PLT_ENTRY_SIZE);
else
{
memcpy (splt->contents, elf_i386_plt0_entry, PLT_ENTRY_SIZE);
bfd_put_32 (output_bfd,
sgot->output_section->vma + sgot->output_offset + 4,
splt->contents + 2);
bfd_put_32 (output_bfd,
sgot->output_section->vma + sgot->output_offset + 8,
splt->contents + 8);
}
/* UnixWare sets the entsize of .plt to 4, although that doesn't
really seem like the right value. */
elf_section_data (splt->output_section)->this_hdr.sh_entsize = 4;
}
}
/* Fill in the first three entries in the global offset table. */
if (sgot->_raw_size > 0)
{
if (sdyn == NULL)
bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents);
else
bfd_put_32 (output_bfd,
sdyn->output_section->vma + sdyn->output_offset,
sgot->contents);
bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 4);
bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 8);
}
elf_section_data (sgot->output_section)->this_hdr.sh_entsize = 4;
return true;
}
#define TARGET_LITTLE_SYM bfd_elf32_i386_vec
#define TARGET_LITTLE_NAME "elf32-i386"
#define ELF_ARCH bfd_arch_i386
#define ELF_MACHINE_CODE EM_386
#define ELF_MAXPAGESIZE 0x1000
#define elf_backend_can_gc_sections 1
#define elf_backend_want_got_plt 1
#define elf_backend_plt_readonly 1
#define elf_backend_want_plt_sym 0
#define elf_backend_got_header_size 12
#define elf_backend_plt_header_size PLT_ENTRY_SIZE
#define elf_info_to_howto elf_i386_info_to_howto
#define elf_info_to_howto_rel elf_i386_info_to_howto_rel
#define bfd_elf32_bfd_final_link _bfd_elf32_gc_common_final_link
#define bfd_elf32_bfd_is_local_label_name elf_i386_is_local_label_name
#define bfd_elf32_bfd_link_hash_table_create elf_i386_link_hash_table_create
#define bfd_elf32_bfd_reloc_type_lookup elf_i386_reloc_type_lookup
#define elf_backend_adjust_dynamic_symbol elf_i386_adjust_dynamic_symbol
#define elf_backend_check_relocs elf_i386_check_relocs
#define elf_backend_create_dynamic_sections _bfd_elf_create_dynamic_sections
#define elf_backend_finish_dynamic_sections elf_i386_finish_dynamic_sections
#define elf_backend_finish_dynamic_symbol elf_i386_finish_dynamic_symbol
#define elf_backend_gc_mark_hook elf_i386_gc_mark_hook
#define elf_backend_gc_sweep_hook elf_i386_gc_sweep_hook
#define elf_backend_relocate_section elf_i386_relocate_section
#define elf_backend_size_dynamic_sections elf_i386_size_dynamic_sections
#include "elf32-target.h"
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