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/* Intel 80386/80486-specific support for 32-bit ELF
Copyright (C) 1993-2016 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 3 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., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include "bfd.h"
#include "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf-nacl.h"
#include "elf-vxworks.h"
#include "bfd_stdint.h"
#include "objalloc.h"
#include "hashtab.h"
#include "dwarf2.h"
#include "opcode/i386.h"
/* 386 uses REL relocations instead of RELA. */
#define USE_REL 1
#include "elf/i386.h"
static reloc_howto_type elf_howto_table[]=
{
HOWTO(R_386_NONE, 0, 3, 0, FALSE, 0, complain_overflow_dont,
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 (R_386_GOTPC + 1)
#define R_386_ext_offset (R_386_TLS_TPOFF - R_386_standard)
/* These relocs are a GNU extension. */
HOWTO(R_386_TLS_TPOFF, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_TPOFF",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_IE, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_IE",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_GOTIE, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_GOTIE",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_LE, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_LE",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_GD, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_GD",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_LDM, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_LDM",
TRUE, 0xffffffff, 0xffffffff, FALSE),
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),
#define R_386_ext (R_386_PC8 + 1 - R_386_ext_offset)
#define R_386_tls_offset (R_386_TLS_LDO_32 - R_386_ext)
/* These are common with Solaris TLS implementation. */
HOWTO(R_386_TLS_LDO_32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_LDO_32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_IE_32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_IE_32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_LE_32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_LE_32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_DTPMOD32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_DTPMOD32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_DTPOFF32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_DTPOFF32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_TPOFF32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_TPOFF32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_SIZE32, 0, 2, 32, FALSE, 0, complain_overflow_unsigned,
bfd_elf_generic_reloc, "R_386_SIZE32",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_GOTDESC, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_GOTDESC",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_TLS_DESC_CALL, 0, 0, 0, FALSE, 0, complain_overflow_dont,
bfd_elf_generic_reloc, "R_386_TLS_DESC_CALL",
FALSE, 0, 0, FALSE),
HOWTO(R_386_TLS_DESC, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_TLS_DESC",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_IRELATIVE, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_IRELATIVE",
TRUE, 0xffffffff, 0xffffffff, FALSE),
HOWTO(R_386_GOT32X, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_GOT32X",
TRUE, 0xffffffff, 0xffffffff, FALSE),
/* Another gap. */
#define R_386_ext2 (R_386_GOT32X + 1 - R_386_tls_offset)
#define R_386_vt_offset (R_386_GNU_VTINHERIT - R_386_ext2)
/* 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), /* pcrel_offset */
/* 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) /* pcrel_offset */
#define R_386_vt (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 (bfd *abfd ATTRIBUTE_UNUSED,
bfd_reloc_code_real_type code)
{
switch (code)
{
case BFD_RELOC_NONE:
TRACE ("BFD_RELOC_NONE");
return &elf_howto_table[R_386_NONE];
case BFD_RELOC_32:
TRACE ("BFD_RELOC_32");
return &elf_howto_table[R_386_32];
case BFD_RELOC_CTOR:
TRACE ("BFD_RELOC_CTOR");
return &elf_howto_table[R_386_32];
case BFD_RELOC_32_PCREL:
TRACE ("BFD_RELOC_PC32");
return &elf_howto_table[R_386_PC32];
case BFD_RELOC_386_GOT32:
TRACE ("BFD_RELOC_386_GOT32");
return &elf_howto_table[R_386_GOT32];
case BFD_RELOC_386_PLT32:
TRACE ("BFD_RELOC_386_PLT32");
return &elf_howto_table[R_386_PLT32];
case BFD_RELOC_386_COPY:
TRACE ("BFD_RELOC_386_COPY");
return &elf_howto_table[R_386_COPY];
case BFD_RELOC_386_GLOB_DAT:
TRACE ("BFD_RELOC_386_GLOB_DAT");
return &elf_howto_table[R_386_GLOB_DAT];
case BFD_RELOC_386_JUMP_SLOT:
TRACE ("BFD_RELOC_386_JUMP_SLOT");
return &elf_howto_table[R_386_JUMP_SLOT];
case BFD_RELOC_386_RELATIVE:
TRACE ("BFD_RELOC_386_RELATIVE");
return &elf_howto_table[R_386_RELATIVE];
case BFD_RELOC_386_GOTOFF:
TRACE ("BFD_RELOC_386_GOTOFF");
return &elf_howto_table[R_386_GOTOFF];
case BFD_RELOC_386_GOTPC:
TRACE ("BFD_RELOC_386_GOTPC");
return &elf_howto_table[R_386_GOTPC];
/* These relocs are a GNU extension. */
case BFD_RELOC_386_TLS_TPOFF:
TRACE ("BFD_RELOC_386_TLS_TPOFF");
return &elf_howto_table[R_386_TLS_TPOFF - R_386_ext_offset];
case BFD_RELOC_386_TLS_IE:
TRACE ("BFD_RELOC_386_TLS_IE");
return &elf_howto_table[R_386_TLS_IE - R_386_ext_offset];
case BFD_RELOC_386_TLS_GOTIE:
TRACE ("BFD_RELOC_386_TLS_GOTIE");
return &elf_howto_table[R_386_TLS_GOTIE - R_386_ext_offset];
case BFD_RELOC_386_TLS_LE:
TRACE ("BFD_RELOC_386_TLS_LE");
return &elf_howto_table[R_386_TLS_LE - R_386_ext_offset];
case BFD_RELOC_386_TLS_GD:
TRACE ("BFD_RELOC_386_TLS_GD");
return &elf_howto_table[R_386_TLS_GD - R_386_ext_offset];
case BFD_RELOC_386_TLS_LDM:
TRACE ("BFD_RELOC_386_TLS_LDM");
return &elf_howto_table[R_386_TLS_LDM - R_386_ext_offset];
case BFD_RELOC_16:
TRACE ("BFD_RELOC_16");
return &elf_howto_table[R_386_16 - R_386_ext_offset];
case BFD_RELOC_16_PCREL:
TRACE ("BFD_RELOC_16_PCREL");
return &elf_howto_table[R_386_PC16 - R_386_ext_offset];
case BFD_RELOC_8:
TRACE ("BFD_RELOC_8");
return &elf_howto_table[R_386_8 - R_386_ext_offset];
case BFD_RELOC_8_PCREL:
TRACE ("BFD_RELOC_8_PCREL");
return &elf_howto_table[R_386_PC8 - R_386_ext_offset];
/* Common with Sun TLS implementation. */
case BFD_RELOC_386_TLS_LDO_32:
TRACE ("BFD_RELOC_386_TLS_LDO_32");
return &elf_howto_table[R_386_TLS_LDO_32 - R_386_tls_offset];
case BFD_RELOC_386_TLS_IE_32:
TRACE ("BFD_RELOC_386_TLS_IE_32");
return &elf_howto_table[R_386_TLS_IE_32 - R_386_tls_offset];
case BFD_RELOC_386_TLS_LE_32:
TRACE ("BFD_RELOC_386_TLS_LE_32");
return &elf_howto_table[R_386_TLS_LE_32 - R_386_tls_offset];
case BFD_RELOC_386_TLS_DTPMOD32:
TRACE ("BFD_RELOC_386_TLS_DTPMOD32");
return &elf_howto_table[R_386_TLS_DTPMOD32 - R_386_tls_offset];
case BFD_RELOC_386_TLS_DTPOFF32:
TRACE ("BFD_RELOC_386_TLS_DTPOFF32");
return &elf_howto_table[R_386_TLS_DTPOFF32 - R_386_tls_offset];
case BFD_RELOC_386_TLS_TPOFF32:
TRACE ("BFD_RELOC_386_TLS_TPOFF32");
return &elf_howto_table[R_386_TLS_TPOFF32 - R_386_tls_offset];
case BFD_RELOC_SIZE32:
TRACE ("BFD_RELOC_SIZE32");
return &elf_howto_table[R_386_SIZE32 - R_386_tls_offset];
case BFD_RELOC_386_TLS_GOTDESC:
TRACE ("BFD_RELOC_386_TLS_GOTDESC");
return &elf_howto_table[R_386_TLS_GOTDESC - R_386_tls_offset];
case BFD_RELOC_386_TLS_DESC_CALL:
TRACE ("BFD_RELOC_386_TLS_DESC_CALL");
return &elf_howto_table[R_386_TLS_DESC_CALL - R_386_tls_offset];
case BFD_RELOC_386_TLS_DESC:
TRACE ("BFD_RELOC_386_TLS_DESC");
return &elf_howto_table[R_386_TLS_DESC - R_386_tls_offset];
case BFD_RELOC_386_IRELATIVE:
TRACE ("BFD_RELOC_386_IRELATIVE");
return &elf_howto_table[R_386_IRELATIVE - R_386_tls_offset];
case BFD_RELOC_386_GOT32X:
TRACE ("BFD_RELOC_386_GOT32X");
return &elf_howto_table[R_386_GOT32X - R_386_tls_offset];
case BFD_RELOC_VTABLE_INHERIT:
TRACE ("BFD_RELOC_VTABLE_INHERIT");
return &elf_howto_table[R_386_GNU_VTINHERIT - R_386_vt_offset];
case BFD_RELOC_VTABLE_ENTRY:
TRACE ("BFD_RELOC_VTABLE_ENTRY");
return &elf_howto_table[R_386_GNU_VTENTRY - R_386_vt_offset];
default:
break;
}
TRACE ("Unknown");
return 0;
}
static reloc_howto_type *
elf_i386_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
const char *r_name)
{
unsigned int i;
for (i = 0; i < sizeof (elf_howto_table) / sizeof (elf_howto_table[0]); i++)
if (elf_howto_table[i].name != NULL
&& strcasecmp (elf_howto_table[i].name, r_name) == 0)
return &elf_howto_table[i];
return NULL;
}
static reloc_howto_type *
elf_i386_rtype_to_howto (bfd *abfd, unsigned r_type)
{
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_tls_offset) - R_386_ext
>= R_386_ext2 - R_386_ext)
&& ((indx = r_type - R_386_vt_offset) - R_386_ext2
>= R_386_vt - R_386_ext2))
{
(*_bfd_error_handler) (_("%B: invalid relocation type %d"),
abfd, (int) r_type);
indx = R_386_NONE;
}
/* PR 17512: file: 0f67f69d. */
if (elf_howto_table [indx].type != r_type)
return NULL;
return &elf_howto_table[indx];
}
static void
elf_i386_info_to_howto_rel (bfd *abfd ATTRIBUTE_UNUSED,
arelent *cache_ptr,
Elf_Internal_Rela *dst)
{
unsigned int r_type = ELF32_R_TYPE (dst->r_info);
cache_ptr->howto = elf_i386_rtype_to_howto (abfd, r_type);
}
/* 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 bfd_boolean
elf_i386_is_local_label_name (bfd *abfd, const char *name)
{
if (name[0] == '.' && name[1] == 'X')
return TRUE;
return _bfd_elf_is_local_label_name (abfd, name);
}
/* Support for core dump NOTE sections. */
static bfd_boolean
elf_i386_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
{
int offset;
size_t size;
if (note->namesz == 8 && strcmp (note->namedata, "FreeBSD") == 0)
{
int pr_version = bfd_get_32 (abfd, note->descdata);
if (pr_version != 1)
return FALSE;
/* pr_cursig */
elf_tdata (abfd)->core->signal = bfd_get_32 (abfd, note->descdata + 20);
/* pr_pid */
elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 24);
/* pr_reg */
offset = 28;
size = bfd_get_32 (abfd, note->descdata + 8);
}
else
{
switch (note->descsz)
{
default:
return FALSE;
case 144: /* Linux/i386 */
/* pr_cursig */
elf_tdata (abfd)->core->signal = bfd_get_16 (abfd, note->descdata + 12);
/* pr_pid */
elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 24);
/* pr_reg */
offset = 72;
size = 68;
break;
}
}
/* Make a ".reg/999" section. */
return _bfd_elfcore_make_pseudosection (abfd, ".reg",
size, note->descpos + offset);
}
static bfd_boolean
elf_i386_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
{
if (note->namesz == 8 && strcmp (note->namedata, "FreeBSD") == 0)
{
int pr_version = bfd_get_32 (abfd, note->descdata);
if (pr_version != 1)
return FALSE;
elf_tdata (abfd)->core->program
= _bfd_elfcore_strndup (abfd, note->descdata + 8, 17);
elf_tdata (abfd)->core->command
= _bfd_elfcore_strndup (abfd, note->descdata + 25, 81);
}
else
{
switch (note->descsz)
{
default:
return FALSE;
case 124: /* Linux/i386 elf_prpsinfo. */
elf_tdata (abfd)->core->pid
= bfd_get_32 (abfd, note->descdata + 12);
elf_tdata (abfd)->core->program
= _bfd_elfcore_strndup (abfd, note->descdata + 28, 16);
elf_tdata (abfd)->core->command
= _bfd_elfcore_strndup (abfd, note->descdata + 44, 80);
}
}
/* Note that for some reason, a spurious space is tacked
onto the end of the args in some (at least one anyway)
implementations, so strip it off if it exists. */
{
char *command = elf_tdata (abfd)->core->command;
int n = strlen (command);
if (0 < n && command[n - 1] == ' ')
command[n - 1] = '\0';
}
return TRUE;
}
/* Functions for the i386 ELF linker.
In order to gain some understanding of code in this file without
knowing all the intricate details of the linker, note the
following:
Functions named elf_i386_* are called by external routines, other
functions are only called locally. elf_i386_* functions appear
in this file more or less in the order in which they are called
from external routines. eg. elf_i386_check_relocs is called
early in the link process, elf_i386_finish_dynamic_sections is
one of the last functions. */
/* The name of the dynamic interpreter. This is put in the .interp
section. */
#define ELF_DYNAMIC_INTERPRETER "/usr/lib/libc.so.1"
/* If ELIMINATE_COPY_RELOCS is non-zero, the linker will try to avoid
copying dynamic variables from a shared lib into an app's dynbss
section, and instead use a dynamic relocation to point into the
shared lib. */
#define ELIMINATE_COPY_RELOCS 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.
Will be padded to PLT_ENTRY_SIZE with htab->plt0_pad_byte. */
static const bfd_byte elf_i386_plt0_entry[12] =
{
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. */
};
/* 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.
Will be padded to PLT_ENTRY_SIZE with htab->plt0_pad_byte. */
static const bfd_byte elf_i386_pic_plt0_entry[12] =
{
0xff, 0xb3, 4, 0, 0, 0, /* pushl 4(%ebx) */
0xff, 0xa3, 8, 0, 0, 0 /* jmp *8(%ebx) */
};
/* 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. */
};
/* Entries in the GOT procedure linkage table look like this. */
static const bfd_byte elf_i386_got_plt_entry[8] =
{
0xff, 0x25, /* jmp indirect */
0, 0, 0, 0, /* replaced with offset of this symbol in .got. */
0x66, 0x90 /* xchg %ax,%ax */
};
/* Entries in the PIC GOT procedure linkage table look like this. */
static const bfd_byte elf_i386_pic_got_plt_entry[8] =
{
0xff, 0xa3, /* jmp *offset(%ebx) */
0, 0, 0, 0, /* replaced with offset of this symbol in .got. */
0x66, 0x90 /* xchg %ax,%ax */
};
/* .eh_frame covering the .plt section. */
static const bfd_byte elf_i386_eh_frame_plt[] =
{
#define PLT_CIE_LENGTH 20
#define PLT_FDE_LENGTH 36
#define PLT_FDE_START_OFFSET 4 + PLT_CIE_LENGTH + 8
#define PLT_FDE_LEN_OFFSET 4 + PLT_CIE_LENGTH + 12
PLT_CIE_LENGTH, 0, 0, 0, /* CIE length */
0, 0, 0, 0, /* CIE ID */
1, /* CIE version */
'z', 'R', 0, /* Augmentation string */
1, /* Code alignment factor */
0x7c, /* Data alignment factor */
8, /* Return address column */
1, /* Augmentation size */
DW_EH_PE_pcrel | DW_EH_PE_sdata4, /* FDE encoding */
DW_CFA_def_cfa, 4, 4, /* DW_CFA_def_cfa: r4 (esp) ofs 4 */
DW_CFA_offset + 8, 1, /* DW_CFA_offset: r8 (eip) at cfa-4 */
DW_CFA_nop, DW_CFA_nop,
PLT_FDE_LENGTH, 0, 0, 0, /* FDE length */
PLT_CIE_LENGTH + 8, 0, 0, 0, /* CIE pointer */
0, 0, 0, 0, /* R_386_PC32 .plt goes here */
0, 0, 0, 0, /* .plt size goes here */
0, /* Augmentation size */
DW_CFA_def_cfa_offset, 8, /* DW_CFA_def_cfa_offset: 8 */
DW_CFA_advance_loc + 6, /* DW_CFA_advance_loc: 6 to __PLT__+6 */
DW_CFA_def_cfa_offset, 12, /* DW_CFA_def_cfa_offset: 12 */
DW_CFA_advance_loc + 10, /* DW_CFA_advance_loc: 10 to __PLT__+16 */
DW_CFA_def_cfa_expression, /* DW_CFA_def_cfa_expression */
11, /* Block length */
DW_OP_breg4, 4, /* DW_OP_breg4 (esp): 4 */
DW_OP_breg8, 0, /* DW_OP_breg8 (eip): 0 */
DW_OP_lit15, DW_OP_and, DW_OP_lit11, DW_OP_ge,
DW_OP_lit2, DW_OP_shl, DW_OP_plus,
DW_CFA_nop, DW_CFA_nop, DW_CFA_nop, DW_CFA_nop
};
struct elf_i386_plt_layout
{
/* The first entry in an absolute procedure linkage table looks like this. */
const bfd_byte *plt0_entry;
unsigned int plt0_entry_size;
/* Offsets into plt0_entry that are to be replaced with GOT[1] and GOT[2]. */
unsigned int plt0_got1_offset;
unsigned int plt0_got2_offset;
/* Later entries in an absolute procedure linkage table look like this. */
const bfd_byte *plt_entry;
unsigned int plt_entry_size;
/* Offsets into plt_entry that are to be replaced with... */
unsigned int plt_got_offset; /* ... address of this symbol in .got. */
unsigned int plt_reloc_offset; /* ... offset into relocation table. */
unsigned int plt_plt_offset; /* ... offset to start of .plt. */
/* Offset into plt_entry where the initial value of the GOT entry points. */
unsigned int plt_lazy_offset;
/* The first entry in a PIC procedure linkage table looks like this. */
const bfd_byte *pic_plt0_entry;
/* Subsequent entries in a PIC procedure linkage table look like this. */
const bfd_byte *pic_plt_entry;
/* .eh_frame covering the .plt section. */
const bfd_byte *eh_frame_plt;
unsigned int eh_frame_plt_size;
};
#define GET_PLT_ENTRY_SIZE(abfd) \
get_elf_i386_backend_data (abfd)->plt->plt_entry_size
/* These are the standard parameters. */
static const struct elf_i386_plt_layout elf_i386_plt =
{
elf_i386_plt0_entry, /* plt0_entry */
sizeof (elf_i386_plt0_entry), /* plt0_entry_size */
2, /* plt0_got1_offset */
8, /* plt0_got2_offset */
elf_i386_plt_entry, /* plt_entry */
PLT_ENTRY_SIZE, /* plt_entry_size */
2, /* plt_got_offset */
7, /* plt_reloc_offset */
12, /* plt_plt_offset */
6, /* plt_lazy_offset */
elf_i386_pic_plt0_entry, /* pic_plt0_entry */
elf_i386_pic_plt_entry, /* pic_plt_entry */
elf_i386_eh_frame_plt, /* eh_frame_plt */
sizeof (elf_i386_eh_frame_plt), /* eh_frame_plt_size */
};
/* On VxWorks, the .rel.plt.unloaded section has absolute relocations
for the PLTResolve stub and then for each PLT entry. */
#define PLTRESOLVE_RELOCS_SHLIB 0
#define PLTRESOLVE_RELOCS 2
#define PLT_NON_JUMP_SLOT_RELOCS 2
/* Architecture-specific backend data for i386. */
struct elf_i386_backend_data
{
/* Parameters describing PLT generation. */
const struct elf_i386_plt_layout *plt;
/* Value used to fill the unused bytes of the first PLT entry. */
bfd_byte plt0_pad_byte;
/* True if the target system is VxWorks. */
int is_vxworks;
};
#define get_elf_i386_backend_data(abfd) \
((const struct elf_i386_backend_data *) \
get_elf_backend_data (abfd)->arch_data)
/* These are the standard parameters. */
static const struct elf_i386_backend_data elf_i386_arch_bed =
{
&elf_i386_plt, /* plt */
0, /* plt0_pad_byte */
0, /* is_vxworks */
};
#define elf_backend_arch_data &elf_i386_arch_bed
/* Is a undefined weak symbol which is resolved to 0. Reference to an
undefined weak symbol is resolved to 0 when building executable if
it isn't dynamic and
1. Has non-GOT/non-PLT relocations in text section. Or
2. Has no GOT/PLT relocation.
*/
#define UNDEFINED_WEAK_RESOLVED_TO_ZERO(INFO, GOT_RELOC, EH) \
((EH)->elf.root.type == bfd_link_hash_undefweak \
&& bfd_link_executable (INFO) \
&& (elf_i386_hash_table (INFO)->interp == NULL \
|| !(GOT_RELOC) \
|| (EH)->has_non_got_reloc \
|| !(INFO)->dynamic_undefined_weak))
/* i386 ELF linker hash entry. */
struct elf_i386_link_hash_entry
{
struct elf_link_hash_entry elf;
/* Track dynamic relocs copied for this symbol. */
struct elf_dyn_relocs *dyn_relocs;
#define GOT_UNKNOWN 0
#define GOT_NORMAL 1
#define GOT_TLS_GD 2
#define GOT_TLS_IE 4
#define GOT_TLS_IE_POS 5
#define GOT_TLS_IE_NEG 6
#define GOT_TLS_IE_BOTH 7
#define GOT_TLS_GDESC 8
#define GOT_TLS_GD_BOTH_P(type) \
((type) == (GOT_TLS_GD | GOT_TLS_GDESC))
#define GOT_TLS_GD_P(type) \
((type) == GOT_TLS_GD || GOT_TLS_GD_BOTH_P (type))
#define GOT_TLS_GDESC_P(type) \
((type) == GOT_TLS_GDESC || GOT_TLS_GD_BOTH_P (type))
#define GOT_TLS_GD_ANY_P(type) \
(GOT_TLS_GD_P (type) || GOT_TLS_GDESC_P (type))
unsigned char tls_type;
/* Symbol is referenced by R_386_GOTOFF relocation. */
unsigned int gotoff_ref : 1;
/* Symbol has GOT or PLT relocations. */
unsigned int has_got_reloc : 1;
/* Symbol has non-GOT/non-PLT relocations in text sections. */
unsigned int has_non_got_reloc : 1;
/* 0: symbol isn't ___tls_get_addr.
1: symbol is ___tls_get_addr.
2: symbol is unknown. */
unsigned int tls_get_addr : 2;
/* Reference count of C/C++ function pointer relocations in read-write
section which can be resolved at run-time. */
bfd_signed_vma func_pointer_refcount;
/* Information about the GOT PLT entry. Filled when there are both
GOT and PLT relocations against the same function. */
union gotplt_union plt_got;
/* Offset of the GOTPLT entry reserved for the TLS descriptor,
starting at the end of the jump table. */
bfd_vma tlsdesc_got;
};
#define elf_i386_hash_entry(ent) ((struct elf_i386_link_hash_entry *)(ent))
struct elf_i386_obj_tdata
{
struct elf_obj_tdata root;
/* tls_type for each local got entry. */
char *local_got_tls_type;
/* GOTPLT entries for TLS descriptors. */
bfd_vma *local_tlsdesc_gotent;
};
#define elf_i386_tdata(abfd) \
((struct elf_i386_obj_tdata *) (abfd)->tdata.any)
#define elf_i386_local_got_tls_type(abfd) \
(elf_i386_tdata (abfd)->local_got_tls_type)
#define elf_i386_local_tlsdesc_gotent(abfd) \
(elf_i386_tdata (abfd)->local_tlsdesc_gotent)
#define is_i386_elf(bfd) \
(bfd_get_flavour (bfd) == bfd_target_elf_flavour \
&& elf_tdata (bfd) != NULL \
&& elf_object_id (bfd) == I386_ELF_DATA)
static bfd_boolean
elf_i386_mkobject (bfd *abfd)
{
return bfd_elf_allocate_object (abfd, sizeof (struct elf_i386_obj_tdata),
I386_ELF_DATA);
}
/* i386 ELF linker hash table. */
struct elf_i386_link_hash_table
{
struct elf_link_hash_table elf;
/* Short-cuts to get to dynamic linker sections. */
asection *interp;
asection *sdynbss;
asection *srelbss;
asection *plt_eh_frame;
asection *plt_got;
union
{
bfd_signed_vma refcount;
bfd_vma offset;
} tls_ldm_got;
/* The amount of space used by the reserved portion of the sgotplt
section, plus whatever space is used by the jump slots. */
bfd_vma sgotplt_jump_table_size;
/* Small local sym cache. */
struct sym_cache sym_cache;
/* _TLS_MODULE_BASE_ symbol. */
struct bfd_link_hash_entry *tls_module_base;
/* Used by local STT_GNU_IFUNC symbols. */
htab_t loc_hash_table;
void * loc_hash_memory;
/* The (unloaded but important) .rel.plt.unloaded section on VxWorks. */
asection *srelplt2;
/* The index of the next unused R_386_TLS_DESC slot in .rel.plt. */
bfd_vma next_tls_desc_index;
/* The index of the next unused R_386_JUMP_SLOT slot in .rel.plt. */
bfd_vma next_jump_slot_index;
/* The index of the next unused R_386_IRELATIVE slot in .rel.plt. */
bfd_vma next_irelative_index;
/* TRUE if there are dynamic relocs against IFUNC symbols that apply
to read-only sections. */
bfd_boolean readonly_dynrelocs_against_ifunc;
};
/* Get the i386 ELF linker hash table from a link_info structure. */
#define elf_i386_hash_table(p) \
(elf_hash_table_id ((struct elf_link_hash_table *) ((p)->hash)) \
== I386_ELF_DATA ? ((struct elf_i386_link_hash_table *) ((p)->hash)) : NULL)
#define elf_i386_compute_jump_table_size(htab) \
((htab)->elf.srelplt->reloc_count * 4)
/* Create an entry in an i386 ELF linker hash table. */
static struct bfd_hash_entry *
elf_i386_link_hash_newfunc (struct bfd_hash_entry *entry,
struct bfd_hash_table *table,
const char *string)
{
/* Allocate the structure if it has not already been allocated by a
subclass. */
if (entry == NULL)
{
entry = (struct bfd_hash_entry *)
bfd_hash_allocate (table, sizeof (struct elf_i386_link_hash_entry));
if (entry == NULL)
return entry;
}
/* Call the allocation method of the superclass. */
entry = _bfd_elf_link_hash_newfunc (entry, table, string);
if (entry != NULL)
{
struct elf_i386_link_hash_entry *eh;
eh = (struct elf_i386_link_hash_entry *) entry;
eh->dyn_relocs = NULL;
eh->tls_type = GOT_UNKNOWN;
eh->gotoff_ref = 0;
eh->has_got_reloc = 0;
eh->has_non_got_reloc = 0;
eh->tls_get_addr = 2;
eh->func_pointer_refcount = 0;
eh->plt_got.offset = (bfd_vma) -1;
eh->tlsdesc_got = (bfd_vma) -1;
}
return entry;
}
/* Compute a hash of a local hash entry. We use elf_link_hash_entry
for local symbol so that we can handle local STT_GNU_IFUNC symbols
as global symbol. We reuse indx and dynstr_index for local symbol
hash since they aren't used by global symbols in this backend. */
static hashval_t
elf_i386_local_htab_hash (const void *ptr)
{
struct elf_link_hash_entry *h
= (struct elf_link_hash_entry *) ptr;
return ELF_LOCAL_SYMBOL_HASH (h->indx, h->dynstr_index);
}
/* Compare local hash entries. */
static int
elf_i386_local_htab_eq (const void *ptr1, const void *ptr2)
{
struct elf_link_hash_entry *h1
= (struct elf_link_hash_entry *) ptr1;
struct elf_link_hash_entry *h2
= (struct elf_link_hash_entry *) ptr2;
return h1->indx == h2->indx && h1->dynstr_index == h2->dynstr_index;
}
/* Find and/or create a hash entry for local symbol. */
static struct elf_link_hash_entry *
elf_i386_get_local_sym_hash (struct elf_i386_link_hash_table *htab,
bfd *abfd, const Elf_Internal_Rela *rel,
bfd_boolean create)
{
struct elf_i386_link_hash_entry e, *ret;
asection *sec = abfd->sections;
hashval_t h = ELF_LOCAL_SYMBOL_HASH (sec->id,
ELF32_R_SYM (rel->r_info));
void **slot;
e.elf.indx = sec->id;
e.elf.dynstr_index = ELF32_R_SYM (rel->r_info);
slot = htab_find_slot_with_hash (htab->loc_hash_table, &e, h,
create ? INSERT : NO_INSERT);
if (!slot)
return NULL;
if (*slot)
{
ret = (struct elf_i386_link_hash_entry *) *slot;
return &ret->elf;
}
ret = (struct elf_i386_link_hash_entry *)
objalloc_alloc ((struct objalloc *) htab->loc_hash_memory,
sizeof (struct elf_i386_link_hash_entry));
if (ret)
{
memset (ret, 0, sizeof (*ret));
ret->elf.indx = sec->id;
ret->elf.dynstr_index = ELF32_R_SYM (rel->r_info);
ret->elf.dynindx = -1;
ret->func_pointer_refcount = 0;
ret->plt_got.offset = (bfd_vma) -1;
*slot = ret;
}
return &ret->elf;
}
/* Destroy an i386 ELF linker hash table. */
static void
elf_i386_link_hash_table_free (bfd *obfd)
{
struct elf_i386_link_hash_table *htab
= (struct elf_i386_link_hash_table *) obfd->link.hash;
if (htab->loc_hash_table)
htab_delete (htab->loc_hash_table);
if (htab->loc_hash_memory)
objalloc_free ((struct objalloc *) htab->loc_hash_memory);
_bfd_elf_link_hash_table_free (obfd);
}
/* Create an i386 ELF linker hash table. */
static struct bfd_link_hash_table *
elf_i386_link_hash_table_create (bfd *abfd)
{
struct elf_i386_link_hash_table *ret;
bfd_size_type amt = sizeof (struct elf_i386_link_hash_table);
ret = (struct elf_i386_link_hash_table *) bfd_zmalloc (amt);
if (ret == NULL)
return NULL;
if (!_bfd_elf_link_hash_table_init (&ret->elf, abfd,
elf_i386_link_hash_newfunc,
sizeof (struct elf_i386_link_hash_entry),
I386_ELF_DATA))
{
free (ret);
return NULL;
}
ret->loc_hash_table = htab_try_create (1024,
elf_i386_local_htab_hash,
elf_i386_local_htab_eq,
NULL);
ret->loc_hash_memory = objalloc_create ();
if (!ret->loc_hash_table || !ret->loc_hash_memory)
{
elf_i386_link_hash_table_free (abfd);
return NULL;
}
ret->elf.root.hash_table_free = elf_i386_link_hash_table_free;
return &ret->elf.root;
}
/* Create .plt, .rel.plt, .got, .got.plt, .rel.got, .dynbss, and
.rel.bss sections in DYNOBJ, and set up shortcuts to them in our
hash table. */
static bfd_boolean
elf_i386_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info)
{
struct elf_i386_link_hash_table *htab;
if (!_bfd_elf_create_dynamic_sections (dynobj, info))
return FALSE;
htab = elf_i386_hash_table (info);
if (htab == NULL)
return FALSE;
/* Set the contents of the .interp section to the interpreter. */
if (bfd_link_executable (info) && !info->nointerp)
{
asection *s = bfd_get_linker_section (dynobj, ".interp");
if (s == NULL)
abort ();
s->size = sizeof ELF_DYNAMIC_INTERPRETER;
s->contents = (unsigned char *) ELF_DYNAMIC_INTERPRETER;
htab->interp = s;
}
htab->sdynbss = bfd_get_linker_section (dynobj, ".dynbss");
if (!htab->sdynbss)
abort ();
if (bfd_link_executable (info))
{
/* Always allow copy relocs for building executables. */
asection *s = bfd_get_linker_section (dynobj, ".rel.bss");
if (s == NULL)
{
const struct elf_backend_data *bed = get_elf_backend_data (dynobj);
s = bfd_make_section_anyway_with_flags (dynobj,
".rel.bss",
(bed->dynamic_sec_flags
| SEC_READONLY));
if (s == NULL
|| ! bfd_set_section_alignment (dynobj, s,
bed->s->log_file_align))
return FALSE;
}
htab->srelbss = s;
}
if (get_elf_i386_backend_data (dynobj)->is_vxworks
&& !elf_vxworks_create_dynamic_sections (dynobj, info,
&htab->srelplt2))
return FALSE;
if (!info->no_ld_generated_unwind_info
&& htab->plt_eh_frame == NULL
&& htab->elf.splt != NULL)
{
flagword flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY
| SEC_HAS_CONTENTS | SEC_IN_MEMORY
| SEC_LINKER_CREATED);
htab->plt_eh_frame
= bfd_make_section_anyway_with_flags (dynobj, ".eh_frame", flags);
if (htab->plt_eh_frame == NULL
|| !bfd_set_section_alignment (dynobj, htab->plt_eh_frame, 2))
return FALSE;
}
return TRUE;
}
/* Copy the extra info we tack onto an elf_link_hash_entry. */
static void
elf_i386_copy_indirect_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *dir,
struct elf_link_hash_entry *ind)
{
struct elf_i386_link_hash_entry *edir, *eind;
edir = (struct elf_i386_link_hash_entry *) dir;
eind = (struct elf_i386_link_hash_entry *) ind;
if (eind->dyn_relocs != NULL)
{
if (edir->dyn_relocs != NULL)
{
struct elf_dyn_relocs **pp;
struct elf_dyn_relocs *p;
/* Add reloc counts against the indirect sym to the direct sym
list. Merge any entries against the same section. */
for (pp = &eind->dyn_relocs; (p = *pp) != NULL; )
{
struct elf_dyn_relocs *q;
for (q = edir->dyn_relocs; q != NULL; q = q->next)
if (q->sec == p->sec)
{
q->pc_count += p->pc_count;
q->count += p->count;
*pp = p->next;
break;
}
if (q == NULL)
pp = &p->next;
}
*pp = edir->dyn_relocs;
}
edir->dyn_relocs = eind->dyn_relocs;
eind->dyn_relocs = NULL;
}
if (ind->root.type == bfd_link_hash_indirect
&& dir->got.refcount <= 0)
{
edir->tls_type = eind->tls_type;
eind->tls_type = GOT_UNKNOWN;
}
/* Copy gotoff_ref so that elf_i386_adjust_dynamic_symbol will
generate a R_386_COPY reloc. */
edir->gotoff_ref |= eind->gotoff_ref;
edir->has_got_reloc |= eind->has_got_reloc;
edir->has_non_got_reloc |= eind->has_non_got_reloc;
if (ELIMINATE_COPY_RELOCS
&& ind->root.type != bfd_link_hash_indirect
&& dir->dynamic_adjusted)
{
/* If called to transfer flags for a weakdef during processing
of elf_adjust_dynamic_symbol, don't copy non_got_ref.
We clear it ourselves for ELIMINATE_COPY_RELOCS. */
dir->ref_dynamic |= ind->ref_dynamic;
dir->ref_regular |= ind->ref_regular;
dir->ref_regular_nonweak |= ind->ref_regular_nonweak;
dir->needs_plt |= ind->needs_plt;
dir->pointer_equality_needed |= ind->pointer_equality_needed;
}
else
{
if (eind->func_pointer_refcount > 0)
{
edir->func_pointer_refcount += eind->func_pointer_refcount;
eind->func_pointer_refcount = 0;
}
_bfd_elf_link_hash_copy_indirect (info, dir, ind);
}
}
/* Return TRUE if the TLS access code sequence support transition
from R_TYPE. */
static bfd_boolean
elf_i386_check_tls_transition (asection *sec,
bfd_byte *contents,
Elf_Internal_Shdr *symtab_hdr,
struct elf_link_hash_entry **sym_hashes,
unsigned int r_type,
const Elf_Internal_Rela *rel,
const Elf_Internal_Rela *relend)
{
unsigned int val, type, reg;
unsigned long r_symndx;
struct elf_link_hash_entry *h;
bfd_vma offset;
bfd_byte *call;
bfd_boolean indirect_call, tls_get_addr;
offset = rel->r_offset;
switch (r_type)
{
case R_386_TLS_GD:
case R_386_TLS_LDM:
if (offset < 2 || (rel + 1) >= relend)
return FALSE;
indirect_call = FALSE;
call = contents + offset + 4;
val = *(call - 5);
type = *(call - 6);
if (r_type == R_386_TLS_GD)
{
/* Check transition from GD access model. Only
leal foo@tlsgd(,%ebx,1), %eax
call ___tls_get_addr@PLT
or
leal foo@tlsgd(%ebx) %eax
call ___tls_get_addr@PLT
nop
or
leal foo@tlsgd(%reg), %eax
call *___tls_get_addr@GOT(%reg)
which may be converted to
addr32 call ___tls_get_addr
can transit to different access model. */
if ((offset + 10) > sec->size
|| (type != 0x8d && type != 0x04))
return FALSE;
if (type == 0x04)
{
/* leal foo@tlsgd(,%ebx,1), %eax
call ___tls_get_addr@PLT */
if (offset < 3)
return FALSE;
if (*(call - 7) != 0x8d
|| val != 0x1d
|| call[0] != 0xe8)
return FALSE;
}
else
{
/* This must be
leal foo@tlsgd(%ebx), %eax
call ___tls_get_addr@PLT
nop
or
leal foo@tlsgd(%reg), %eax
call *___tls_get_addr@GOT(%reg)
which may be converted to
addr32 call ___tls_get_addr
%eax can't be used as the GOT base register since it
is used to pass parameter to ___tls_get_addr. */
reg = val & 7;
if ((val & 0xf8) != 0x80 || reg == 4 || reg == 0)
return FALSE;
indirect_call = call[0] == 0xff;
if (!(reg == 3 && call[0] == 0xe8 && call[5] == 0x90)
&& !(call[0] == 0x67 && call[1] == 0xe8)
&& !(indirect_call
&& (call[1] & 0xf8) == 0x90
&& (call[1] & 0x7) == reg))
return FALSE;
}
}
else
{
/* Check transition from LD access model. Only
leal foo@tlsldm(%ebx), %eax
call ___tls_get_addr@PLT
or
leal foo@tlsldm(%reg), %eax
call *___tls_get_addr@GOT(%reg)
which may be converted to
addr32 call ___tls_get_addr
can transit to different access model. */
if (type != 0x8d || (offset + 9) > sec->size)
return FALSE;
/* %eax can't be used as the GOT base register since it is
used to pass parameter to ___tls_get_addr. */
reg = val & 7;
if ((val & 0xf8) != 0x80 || reg == 4 || reg == 0)
return FALSE;
indirect_call = call[0] == 0xff;
if (!(reg == 3 && call[0] == 0xe8)
&& !(call[0] == 0x67 && call[1] == 0xe8)
&& !(indirect_call
&& (call[1] & 0xf8) == 0x90
&& (call[1] & 0x7) == reg))
return FALSE;
}
r_symndx = ELF32_R_SYM (rel[1].r_info);
if (r_symndx < symtab_hdr->sh_info)
return FALSE;
tls_get_addr = FALSE;
h = sym_hashes[r_symndx - symtab_hdr->sh_info];
if (h != NULL && h->root.root.string != NULL)
{
struct elf_i386_link_hash_entry *eh
= (struct elf_i386_link_hash_entry *) h;
tls_get_addr = eh->tls_get_addr == 1;
if (eh->tls_get_addr > 1)
{
/* Use strncmp to check ___tls_get_addr since
___tls_get_addr may be versioned. */
if (strncmp (h->root.root.string, "___tls_get_addr", 15)
== 0)
{
eh->tls_get_addr = 1;
tls_get_addr = TRUE;
}
else
eh->tls_get_addr = 0;
}
}
if (!tls_get_addr)
return FALSE;
else if (indirect_call)
return (ELF32_R_TYPE (rel[1].r_info) == R_386_GOT32X);
else
return (ELF32_R_TYPE (rel[1].r_info) == R_386_PC32
|| ELF32_R_TYPE (rel[1].r_info) == R_386_PLT32);
case R_386_TLS_IE:
/* Check transition from IE access model:
movl foo@indntpoff(%rip), %eax
movl foo@indntpoff(%rip), %reg
addl foo@indntpoff(%rip), %reg
*/
if (offset < 1 || (offset + 4) > sec->size)
return FALSE;
/* Check "movl foo@tpoff(%rip), %eax" first. */
val = bfd_get_8 (abfd, contents + offset - 1);
if (val == 0xa1)
return TRUE;
if (offset < 2)
return FALSE;
/* Check movl|addl foo@tpoff(%rip), %reg. */
type = bfd_get_8 (abfd, contents + offset - 2);
return ((type == 0x8b || type == 0x03)
&& (val & 0xc7) == 0x05);
case R_386_TLS_GOTIE:
case R_386_TLS_IE_32:
/* Check transition from {IE_32,GOTIE} access model:
subl foo@{tpoff,gontoff}(%reg1), %reg2
movl foo@{tpoff,gontoff}(%reg1), %reg2
addl foo@{tpoff,gontoff}(%reg1), %reg2
*/
if (offset < 2 || (offset + 4) > sec->size)
return FALSE;
val = bfd_get_8 (abfd, contents + offset - 1);
if ((val & 0xc0) != 0x80 || (val & 7) == 4)
return FALSE;
type = bfd_get_8 (abfd, contents + offset - 2);
return type == 0x8b || type == 0x2b || type == 0x03;
case R_386_TLS_GOTDESC:
/* Check transition from GDesc access model:
leal x@tlsdesc(%ebx), %eax
Make sure it's a leal adding ebx to a 32-bit offset
into any register, although it's probably almost always
going to be eax. */
if (offset < 2 || (offset + 4) > sec->size)
return FALSE;
if (bfd_get_8 (abfd, contents + offset - 2) != 0x8d)
return FALSE;
val = bfd_get_8 (abfd, contents + offset - 1);
return (val & 0xc7) == 0x83;
case R_386_TLS_DESC_CALL:
/* Check transition from GDesc access model:
call *x@tlsdesc(%eax)
*/
if (offset + 2 <= sec->size)
{
/* Make sure that it's a call *x@tlsdesc(%eax). */
call = contents + offset;
return call[0] == 0xff && call[1] == 0x10;
}
return FALSE;
default:
abort ();
}
}
/* Return TRUE if the TLS access transition is OK or no transition
will be performed. Update R_TYPE if there is a transition. */
static bfd_boolean
elf_i386_tls_transition (struct bfd_link_info *info, bfd *abfd,
asection *sec, bfd_byte *contents,
Elf_Internal_Shdr *symtab_hdr,
struct elf_link_hash_entry **sym_hashes,
unsigned int *r_type, int tls_type,
const Elf_Internal_Rela *rel,
const Elf_Internal_Rela *relend,
struct elf_link_hash_entry *h,
unsigned long r_symndx,
bfd_boolean from_relocate_section)
{
unsigned int from_type = *r_type;
unsigned int to_type = from_type;
bfd_boolean check = TRUE;
/* Skip TLS transition for functions. */
if (h != NULL
&& (h->type == STT_FUNC
|| h->type == STT_GNU_IFUNC))
return TRUE;
switch (from_type)
{
case R_386_TLS_GD:
case R_386_TLS_GOTDESC:
case R_386_TLS_DESC_CALL:
case R_386_TLS_IE_32:
case R_386_TLS_IE:
case R_386_TLS_GOTIE:
if (bfd_link_executable (info))
{
if (h == NULL)
to_type = R_386_TLS_LE_32;
else if (from_type != R_386_TLS_IE
&& from_type != R_386_TLS_GOTIE)
to_type = R_386_TLS_IE_32;
}
/* When we are called from elf_i386_relocate_section, there may
be additional transitions based on TLS_TYPE. */
if (from_relocate_section)
{
unsigned int new_to_type = to_type;
if (bfd_link_executable (info)
&& h != NULL
&& h->dynindx == -1
&& (tls_type & GOT_TLS_IE))
new_to_type = R_386_TLS_LE_32;
if (to_type == R_386_TLS_GD
|| to_type == R_386_TLS_GOTDESC
|| to_type == R_386_TLS_DESC_CALL)
{
if (tls_type == GOT_TLS_IE_POS)
new_to_type = R_386_TLS_GOTIE;
else if (tls_type & GOT_TLS_IE)
new_to_type = R_386_TLS_IE_32;
}
/* We checked the transition before when we were called from
elf_i386_check_relocs. We only want to check the new
transition which hasn't been checked before. */
check = new_to_type != to_type && from_type == to_type;
to_type = new_to_type;
}
break;
case R_386_TLS_LDM:
if (bfd_link_executable (info))
to_type = R_386_TLS_LE_32;
break;
default:
return TRUE;
}
/* Return TRUE if there is no transition. */
if (from_type == to_type)
return TRUE;
/* Check if the transition can be performed. */
if (check
&& ! elf_i386_check_tls_transition (sec, contents,
symtab_hdr, sym_hashes,
from_type, rel, relend))
{
reloc_howto_type *from, *to;
const char *name;
from = elf_i386_rtype_to_howto (abfd, from_type);
to = elf_i386_rtype_to_howto (abfd, to_type);
if (h)
name = h->root.root.string;
else
{
struct elf_i386_link_hash_table *htab;
htab = elf_i386_hash_table (info);
if (htab == NULL)
name = "*unknown*";
else
{
Elf_Internal_Sym *isym;
isym = bfd_sym_from_r_symndx (&htab->sym_cache,
abfd, r_symndx);
name = bfd_elf_sym_name (abfd, symtab_hdr, isym, NULL);
}
}
(*_bfd_error_handler)
(_("%B: TLS transition from %s to %s against `%s' at 0x%lx "
"in section `%A' failed"),
abfd, sec, from->name, to->name, name,
(unsigned long) rel->r_offset);
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
*r_type = to_type;
return TRUE;
}
/* With the local symbol, foo, we convert
mov foo@GOT[(%reg1)], %reg2
to
lea foo[@GOTOFF(%reg1)], %reg2
and convert
call/jmp *foo@GOT[(%reg)]
to
nop call foo/jmp foo nop
When PIC is false, convert
test %reg1, foo@GOT[(%reg2)]
to
test $foo, %reg1
and convert
binop foo@GOT[(%reg1)], %reg2
to
binop $foo, %reg2
where binop is one of adc, add, and, cmp, or, sbb, sub, xor
instructions. */
static
bfd_boolean
elf_i386_convert_load_reloc (bfd *abfd, Elf_Internal_Shdr *symtab_hdr,
bfd_byte *contents,
Elf_Internal_Rela *irel,
struct elf_link_hash_entry *h,
bfd_boolean *converted,
struct bfd_link_info *link_info)
{
struct elf_i386_link_hash_table *htab;
unsigned int opcode;
unsigned int modrm;
bfd_boolean baseless;
Elf_Internal_Sym *isym;
unsigned int addend;
unsigned int nop;
bfd_vma nop_offset;
bfd_boolean is_pic;
bfd_boolean to_reloc_32;
unsigned int r_type;
unsigned int r_symndx;
bfd_vma roff = irel->r_offset;
if (roff < 2)
return TRUE;
/* Addend for R_386_GOT32X relocations must be 0. */
addend = bfd_get_32 (abfd, contents + roff);
if (addend != 0)
return TRUE;
htab = elf_i386_hash_table (link_info);
is_pic = bfd_link_pic (link_info);
r_type = ELF32_R_TYPE (irel->r_info);
r_symndx = ELF32_R_SYM (irel->r_info);
modrm = bfd_get_8 (abfd, contents + roff - 1);
baseless = (modrm & 0xc7) == 0x5;
if (baseless && is_pic)
{
/* For PIC, disallow R_386_GOT32X without a base register
since we don't know what the GOT base is. */
const char *name;
if (h == NULL)
{
isym = bfd_sym_from_r_symndx (&htab->sym_cache, abfd,
r_symndx);
name = bfd_elf_sym_name (abfd, symtab_hdr, isym, NULL);
}
else
name = h->root.root.string;
(*_bfd_error_handler)
(_("%B: direct GOT relocation R_386_GOT32X against `%s' without base register can not be used when making a shared object"),
abfd, name);
return FALSE;
}
opcode = bfd_get_8 (abfd, contents + roff - 2);
/* Convert to R_386_32 if PIC is false or there is no base
register. */
to_reloc_32 = !is_pic || baseless;
/* Try to convert R_386_GOT32X. Get the symbol referred to by the
reloc. */
if (h == NULL)
{
if (opcode == 0x0ff)
/* Convert "call/jmp *foo@GOT[(%reg)]". */
goto convert_branch;
else
/* Convert "mov foo@GOT[(%reg1)], %reg2",
"test %reg1, foo@GOT(%reg2)" and
"binop foo@GOT[(%reg1)], %reg2". */
goto convert_load;
}
/* Undefined weak symbol is only bound locally in executable
and its reference is resolved as 0. */
if (UNDEFINED_WEAK_RESOLVED_TO_ZERO (link_info, TRUE,
elf_i386_hash_entry (h)))
{
if (opcode == 0xff)
{
/* No direct branch to 0 for PIC. */
if (is_pic)
return TRUE;
else
goto convert_branch;
}
else
{
/* We can convert load of address 0 to R_386_32. */
to_reloc_32 = TRUE;
goto convert_load;
}
}
if (opcode == 0xff)
{
/* We have "call/jmp *foo@GOT[(%reg)]". */
if ((h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& SYMBOL_REFERENCES_LOCAL (link_info, h))
{
/* The function is locally defined. */
convert_branch:
/* Convert R_386_GOT32X to R_386_PC32. */
if (modrm == 0x15 || (modrm & 0xf8) == 0x90)
{
struct elf_i386_link_hash_entry *eh
= (struct elf_i386_link_hash_entry *) h;
/* Convert to "nop call foo". ADDR_PREFIX_OPCODE
is a nop prefix. */
modrm = 0xe8;
/* To support TLS optimization, always use addr32 prefix
for "call *___tls_get_addr@GOT(%reg)". */
if (eh && eh->tls_get_addr == 1)
{
nop = 0x67;
nop_offset = irel->r_offset - 2;
}
else
{
nop = link_info->call_nop_byte;
if (link_info->call_nop_as_suffix)
{
nop_offset = roff + 3;
irel->r_offset -= 1;
}
else
nop_offset = roff - 2;
}
}
else
{
/* Convert to "jmp foo nop". */
modrm = 0xe9;
nop = NOP_OPCODE;
nop_offset = roff + 3;
irel->r_offset -= 1;
}
bfd_put_8 (abfd, nop, contents + nop_offset);
bfd_put_8 (abfd, modrm, contents + irel->r_offset - 1);
/* When converting to PC-relative relocation, we
need to adjust addend by -4. */
bfd_put_32 (abfd, -4, contents + irel->r_offset);
irel->r_info = ELF32_R_INFO (r_symndx, R_386_PC32);
*converted = TRUE;
}
}
else
{
/* We have "mov foo@GOT[(%re1g)], %reg2",
"test %reg1, foo@GOT(%reg2)" and
"binop foo@GOT[(%reg1)], %reg2".
Avoid optimizing _DYNAMIC since ld.so may use its
link-time address. */
if (h == htab->elf.hdynamic)
return TRUE;
/* def_regular is set by an assignment in a linker script in
bfd_elf_record_link_assignment. */
if ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& SYMBOL_REFERENCES_LOCAL (link_info, h))
{
convert_load:
if (opcode == 0x8b)
{
if (to_reloc_32)
{
/* Convert "mov foo@GOT[(%reg1)], %reg2" to
"mov $foo, %reg2" with R_386_32. */
r_type = R_386_32;
modrm = 0xc0 | (modrm & 0x38) >> 3;
bfd_put_8 (abfd, modrm, contents + roff - 1);
opcode = 0xc7;
}
else
{
/* Convert "mov foo@GOT(%reg1), %reg2" to
"lea foo@GOTOFF(%reg1), %reg2". */
r_type = R_386_GOTOFF;
opcode = 0x8d;
}
}
else
{
/* Only R_386_32 is supported. */
if (!to_reloc_32)
return TRUE;
if (opcode == 0x85)
{
/* Convert "test %reg1, foo@GOT(%reg2)" to
"test $foo, %reg1". */
modrm = 0xc0 | (modrm & 0x38) >> 3;
opcode = 0xf7;
}
else
{
/* Convert "binop foo@GOT(%reg1), %reg2" to
"binop $foo, %reg2". */
modrm = (0xc0
| (modrm & 0x38) >> 3
| (opcode & 0x3c));
opcode = 0x81;
}
bfd_put_8 (abfd, modrm, contents + roff - 1);
r_type = R_386_32;
}
bfd_put_8 (abfd, opcode, contents + roff - 2);
irel->r_info = ELF32_R_INFO (r_symndx, r_type);
*converted = TRUE;
}
}
return TRUE;
}
/* Rename some of the generic section flags to better document how they
are used here. */
#define need_convert_load sec_flg0
#define check_relocs_failed sec_flg1
/* Look through the relocs for a section during the first phase, and
calculate needed space in the global offset table, procedure linkage
table, and dynamic reloc sections. */
static bfd_boolean
elf_i386_check_relocs (bfd *abfd,
struct bfd_link_info *info,
asection *sec,
const Elf_Internal_Rela *relocs)
{
struct elf_i386_link_hash_table *htab;
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry **sym_hashes;
const Elf_Internal_Rela *rel;
const Elf_Internal_Rela *rel_end;
asection *sreloc;
bfd_byte *contents;
bfd_boolean use_plt_got;
if (bfd_link_relocatable (info))
return TRUE;
/* Don't do anything special with non-loaded, non-alloced sections.
In particular, any relocs in such sections should not affect GOT
and PLT reference counting (ie. we don't allow them to create GOT
or PLT entries), there's no possibility or desire to optimize TLS
relocs, and there's not much point in propagating relocs to shared
libs that the dynamic linker won't relocate. */
if ((sec->flags & SEC_ALLOC) == 0)
return TRUE;
BFD_ASSERT (is_i386_elf (abfd));
htab = elf_i386_hash_table (info);
if (htab == NULL)
{
sec->check_relocs_failed = 1;
return FALSE;
}
/* Get the section contents. */
if (elf_section_data (sec)->this_hdr.contents != NULL)
contents = elf_section_data (sec)->this_hdr.contents;
else if (!bfd_malloc_and_get_section (abfd, sec, &contents))
{
sec->check_relocs_failed = 1;
return FALSE;
}
use_plt_got = (!get_elf_i386_backend_data (abfd)->is_vxworks
&& (get_elf_i386_backend_data (abfd)
== &elf_i386_arch_bed));
symtab_hdr = &elf_symtab_hdr (abfd);
sym_hashes = elf_sym_hashes (abfd);
sreloc = NULL;
rel_end = relocs + sec->reloc_count;
for (rel = relocs; rel < rel_end; rel++)
{
unsigned int r_type;
unsigned long r_symndx;
struct elf_link_hash_entry *h;
struct elf_i386_link_hash_entry *eh;
Elf_Internal_Sym *isym;
const char *name;
bfd_boolean size_reloc;
r_symndx = ELF32_R_SYM (rel->r_info);
r_type = ELF32_R_TYPE (rel->r_info);
if (r_symndx >= NUM_SHDR_ENTRIES (symtab_hdr))
{
(*_bfd_error_handler) (_("%B: bad symbol index: %d"),
abfd,
r_symndx);
goto error_return;
}
if (r_symndx < symtab_hdr->sh_info)
{
/* A local symbol. */
isym = bfd_sym_from_r_symndx (&htab->sym_cache,
abfd, r_symndx);
if (isym == NULL)
goto error_return;
/* Check relocation against local STT_GNU_IFUNC symbol. */
if (ELF32_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
{
h = elf_i386_get_local_sym_hash (htab, abfd, rel, TRUE);
if (h == NULL)
goto error_return;
/* Fake a STT_GNU_IFUNC symbol. */
h->type = STT_GNU_IFUNC;
h->def_regular = 1;
h->ref_regular = 1;
h->forced_local = 1;
h->root.type = bfd_link_hash_defined;
}
else
h = NULL;
}
else
{
isym = NULL;
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;
}
eh = (struct elf_i386_link_hash_entry *) h;
if (h != NULL)
{
switch (r_type)
{
default:
break;
case R_386_GOTOFF:
eh->gotoff_ref = 1;
case R_386_32:
case R_386_PC32:
case R_386_PLT32:
case R_386_GOT32:
case R_386_GOT32X:
if (htab->elf.dynobj == NULL)
htab->elf.dynobj = abfd;
/* Create the ifunc sections for static executables. */
if (h->type == STT_GNU_IFUNC
&& !_bfd_elf_create_ifunc_sections (htab->elf.dynobj,
info))
goto error_return;
break;
}
/* It is referenced by a non-shared object. */
h->ref_regular = 1;
h->root.non_ir_ref = 1;
if (h->type == STT_GNU_IFUNC)
elf_tdata (info->output_bfd)->has_gnu_symbols
|= elf_gnu_symbol_ifunc;
}
if (! elf_i386_tls_transition (info, abfd, sec, contents,
symtab_hdr, sym_hashes,
&r_type, GOT_UNKNOWN,
rel, rel_end, h, r_symndx, FALSE))
goto error_return;
switch (r_type)
{
case R_386_TLS_LDM:
htab->tls_ldm_got.refcount += 1;
goto create_got;
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;
eh->has_got_reloc = 1;
h->needs_plt = 1;
h->plt.refcount += 1;
break;
case R_386_SIZE32:
size_reloc = TRUE;
goto do_size;
case R_386_TLS_IE_32:
case R_386_TLS_IE:
case R_386_TLS_GOTIE:
if (!bfd_link_executable (info))
info->flags |= DF_STATIC_TLS;
/* Fall through */
case R_386_GOT32:
case R_386_GOT32X:
case R_386_TLS_GD:
case R_386_TLS_GOTDESC:
case R_386_TLS_DESC_CALL:
/* This symbol requires a global offset table entry. */
{
int tls_type, old_tls_type;
switch (r_type)
{
default:
case R_386_GOT32:
case R_386_GOT32X:
tls_type = GOT_NORMAL;
break;
case R_386_TLS_GD: tls_type = GOT_TLS_GD; break;
case R_386_TLS_GOTDESC:
case R_386_TLS_DESC_CALL:
tls_type = GOT_TLS_GDESC; break;
case R_386_TLS_IE_32:
if (ELF32_R_TYPE (rel->r_info) == r_type)
tls_type = GOT_TLS_IE_NEG;
else
/* If this is a GD->IE transition, we may use either of
R_386_TLS_TPOFF and R_386_TLS_TPOFF32. */
tls_type = GOT_TLS_IE;
break;
case R_386_TLS_IE:
case R_386_TLS_GOTIE:
tls_type = GOT_TLS_IE_POS; break;
}
if (h != NULL)
{
h->got.refcount += 1;
old_tls_type = elf_i386_hash_entry(h)->tls_type;
}
else
{
bfd_signed_vma *local_got_refcounts;
/* This is a global offset table entry for a local symbol. */
local_got_refcounts = elf_local_got_refcounts (abfd);
if (local_got_refcounts == NULL)
{
bfd_size_type size;
size = symtab_hdr->sh_info;
size *= (sizeof (bfd_signed_vma)
+ sizeof (bfd_vma) + sizeof(char));
local_got_refcounts = (bfd_signed_vma *)
bfd_zalloc (abfd, size);
if (local_got_refcounts == NULL)
goto error_return;
elf_local_got_refcounts (abfd) = local_got_refcounts;
elf_i386_local_tlsdesc_gotent (abfd)
= (bfd_vma *) (local_got_refcounts + symtab_hdr->sh_info);
elf_i386_local_got_tls_type (abfd)
= (char *) (local_got_refcounts + 2 * symtab_hdr->sh_info);
}
local_got_refcounts[r_symndx] += 1;
old_tls_type = elf_i386_local_got_tls_type (abfd) [r_symndx];
}
if ((old_tls_type & GOT_TLS_IE) && (tls_type & GOT_TLS_IE))
tls_type |= old_tls_type;
/* If a TLS symbol is accessed using IE at least once,
there is no point to use dynamic model for it. */
else if (old_tls_type != tls_type && old_tls_type != GOT_UNKNOWN
&& (! GOT_TLS_GD_ANY_P (old_tls_type)
|| (tls_type & GOT_TLS_IE) == 0))
{
if ((old_tls_type & GOT_TLS_IE) && GOT_TLS_GD_ANY_P (tls_type))
tls_type = old_tls_type;
else if (GOT_TLS_GD_ANY_P (old_tls_type)
&& GOT_TLS_GD_ANY_P (tls_type))
tls_type |= old_tls_type;
else
{
if (h)
name = h->root.root.string;
else
name = bfd_elf_sym_name (abfd, symtab_hdr, isym,
NULL);
(*_bfd_error_handler)
(_("%B: `%s' accessed both as normal and "
"thread local symbol"),
abfd, name);
bfd_set_error (bfd_error_bad_value);
goto error_return;
}
}
if (old_tls_type != tls_type)
{
if (h != NULL)
elf_i386_hash_entry (h)->tls_type = tls_type;
else
elf_i386_local_got_tls_type (abfd) [r_symndx] = tls_type;
}
}
/* Fall through */
case R_386_GOTOFF:
case R_386_GOTPC:
create_got:
if (htab->elf.sgot == NULL)
{
if (htab->elf.dynobj == NULL)
htab->elf.dynobj = abfd;
if (!_bfd_elf_create_got_section (htab->elf.dynobj, info))
goto error_return;
}
if (r_type != R_386_TLS_IE)
{
if (eh != NULL)
eh->has_got_reloc = 1;
break;
}
/* Fall through */
case R_386_TLS_LE_32:
case R_386_TLS_LE:
if (eh != NULL)
eh->has_got_reloc = 1;
if (bfd_link_executable (info))
break;
info->flags |= DF_STATIC_TLS;
goto do_relocation;
case R_386_32:
case R_386_PC32:
if (eh != NULL && (sec->flags & SEC_CODE) != 0)
eh->has_non_got_reloc = 1;
do_relocation:
/* We are called after all symbols have been resolved. Only
relocation against STT_GNU_IFUNC symbol must go through
PLT. */
if (h != NULL
&& (bfd_link_executable (info)
|| h->type == STT_GNU_IFUNC))
{
/* If this reloc is in a read-only section, we might
need a copy reloc. We can't check reliably at this
stage whether the section is read-only, as input
sections have not yet been mapped to output sections.
Tentatively set the flag for now, and correct in
adjust_dynamic_symbol. */
h->non_got_ref = 1;
/* We may need a .plt entry if the symbol is a function
defined in a shared lib or is a STT_GNU_IFUNC function
referenced from the code or read-only section. */
if (!h->def_regular
|| (sec->flags & (SEC_CODE | SEC_READONLY)) != 0)
h->plt.refcount += 1;
if (r_type == R_386_PC32)
{
/* Since something like ".long foo - ." may be used
as pointer, make sure that PLT is used if foo is
a function defined in a shared library. */
if ((sec->flags & SEC_CODE) == 0)
h->pointer_equality_needed = 1;
}
else
{
h->pointer_equality_needed = 1;
/* R_386_32 can be resolved at run-time. */
if (r_type == R_386_32
&& (sec->flags & SEC_READONLY) == 0)
eh->func_pointer_refcount += 1;
}
}
size_reloc = FALSE;
do_size:
/* 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). In case of a weak definition,
DEF_REGULAR may be cleared later by a strong definition in
a shared library. We account for that possibility below by
storing information in the relocs_copied field of the hash
table entry. A similar situation occurs when creating
shared libraries and symbol visibility changes render the
symbol local.
If on the other hand, we are creating an executable, we
may need to keep relocations for symbols satisfied by a
dynamic library if we manage to avoid copy relocs for the
symbol.
Generate dynamic pointer relocation against STT_GNU_IFUNC
symbol in the non-code section. */
if ((bfd_link_pic (info)
&& (r_type != R_386_PC32
|| (h != NULL
&& (! (bfd_link_pie (info)
|| SYMBOLIC_BIND (info, h))
|| h->root.type == bfd_link_hash_defweak
|| !h->def_regular))))
|| (h != NULL
&& h->type == STT_GNU_IFUNC
&& r_type == R_386_32
&& (sec->flags & SEC_CODE) == 0)
|| (ELIMINATE_COPY_RELOCS
&& !bfd_link_pic (info)
&& h != NULL
&& (h->root.type == bfd_link_hash_defweak
|| !h->def_regular)))
{
struct elf_dyn_relocs *p;
struct elf_dyn_relocs **head;
/* We must copy these reloc types into the output file.
Create a reloc section in dynobj and make room for
this reloc. */
if (sreloc == NULL)
{
if (htab->elf.dynobj == NULL)
htab->elf.dynobj = abfd;
sreloc = _bfd_elf_make_dynamic_reloc_section
(sec, htab->elf.dynobj, 2, abfd, /*rela?*/ FALSE);
if (sreloc == NULL)
goto error_return;
}
/* If this is a global symbol, we count the number of
relocations we need for this symbol. */
if (h != NULL)
{
head = &eh->dyn_relocs;
}
else
{
/* Track dynamic relocs needed for local syms too.
We really need local syms available to do this
easily. Oh well. */
void **vpp;
asection *s;
isym = bfd_sym_from_r_symndx (&htab->sym_cache,
abfd, r_symndx);
if (isym == NULL)
goto error_return;
s = bfd_section_from_elf_index (abfd, isym->st_shndx);
if (s == NULL)
s = sec;
vpp = &elf_section_data (s)->local_dynrel;
head = (struct elf_dyn_relocs **)vpp;
}
p = *head;
if (p == NULL || p->sec != sec)
{
bfd_size_type amt = sizeof *p;
p = (struct elf_dyn_relocs *) bfd_alloc (htab->elf.dynobj,
amt);
if (p == NULL)
goto error_return;
p->next = *head;
*head = p;
p->sec = sec;
p->count = 0;
p->pc_count = 0;
}
p->count += 1;
/* Count size relocation as PC-relative relocation. */
if (r_type == R_386_PC32 || size_reloc)
p->pc_count += 1;
}
break;
/* This relocation describes the C++ object vtable hierarchy.
Reconstruct it for later use during GC. */
case R_386_GNU_VTINHERIT:
if (!bfd_elf_gc_record_vtinherit (abfd, sec, h, rel->r_offset))
goto error_return;
break;
/* This relocation describes which C++ vtable entries are actually
used. Record for later use during GC. */
case R_386_GNU_VTENTRY:
BFD_ASSERT (h != NULL);
if (h != NULL
&& !bfd_elf_gc_record_vtentry (abfd, sec, h, rel->r_offset))
goto error_return;
break;
default:
break;
}
if (use_plt_got
&& h != NULL
&& h->plt.refcount > 0
&& (((info->flags & DF_BIND_NOW) && !h->pointer_equality_needed)
|| h->got.refcount > 0)
&& htab->plt_got == NULL)
{
/* Create the GOT procedure linkage table. */
unsigned int plt_got_align;
const struct elf_backend_data *bed;
bed = get_elf_backend_data (info->output_bfd);
BFD_ASSERT (sizeof (elf_i386_got_plt_entry) == 8
&& (sizeof (elf_i386_got_plt_entry)
== sizeof (elf_i386_pic_got_plt_entry)));
plt_got_align = 3;
if (htab->elf.dynobj == NULL)
htab->elf.dynobj = abfd;
htab->plt_got
= bfd_make_section_anyway_with_flags (htab->elf.dynobj,
".plt.got",
(bed->dynamic_sec_flags
| SEC_ALLOC
| SEC_CODE
| SEC_LOAD
| SEC_READONLY));
if (htab->plt_got == NULL
|| !bfd_set_section_alignment (htab->elf.dynobj,
htab->plt_got,
plt_got_align))
goto error_return;
}
if (r_type == R_386_GOT32X
&& (h == NULL || h->type != STT_GNU_IFUNC))
sec->need_convert_load = 1;
}
if (elf_section_data (sec)->this_hdr.contents != contents)
{
if (!info->keep_memory)
free (contents);
else
{
/* Cache the section contents for elf_link_input_bfd. */
elf_section_data (sec)->this_hdr.contents = contents;
}
}
return TRUE;
error_return:
if (elf_section_data (sec)->this_hdr.contents != contents)
free (contents);
sec->check_relocs_failed = 1;
return FALSE;
}
/* Return the section that should be marked against GC for a given
relocation. */
static asection *
elf_i386_gc_mark_hook (asection *sec,
struct bfd_link_info *info,
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:
return NULL;
}
return _bfd_elf_gc_mark_hook (sec, info, rel, h, sym);
}
/* Remove undefined weak symbol from the dynamic symbol table if it
is resolved to 0. */
static bfd_boolean
elf_i386_fixup_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
if (h->dynindx != -1
&& UNDEFINED_WEAK_RESOLVED_TO_ZERO (info,
elf_i386_hash_entry (h)->has_got_reloc,
elf_i386_hash_entry (h)))
{
h->dynindx = -1;
_bfd_elf_strtab_delref (elf_hash_table (info)->dynstr,
h->dynstr_index);
}
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 bfd_boolean
elf_i386_adjust_dynamic_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
struct elf_i386_link_hash_table *htab;
asection *s;
struct elf_i386_link_hash_entry *eh;
struct elf_dyn_relocs *p;
/* STT_GNU_IFUNC symbol must go through PLT. */
if (h->type == STT_GNU_IFUNC)
{
/* All local STT_GNU_IFUNC references must be treate as local
calls via local PLT. */
if (h->ref_regular
&& SYMBOL_CALLS_LOCAL (info, h))
{
bfd_size_type pc_count = 0, count = 0;
struct elf_dyn_relocs **pp;
eh = (struct elf_i386_link_hash_entry *) h;
for (pp = &eh->dyn_relocs; (p = *pp) != NULL; )
{
pc_count += p->pc_count;
p->count -= p->pc_count;
p->pc_count = 0;
count += p->count;
if (p->count == 0)
*pp = p->next;
else
pp = &p->next;
}
if (pc_count || count)
{
h->non_got_ref = 1;
if (pc_count)
{
/* Increment PLT reference count only for PC-relative
references. */
h->needs_plt = 1;
if (h->plt.refcount <= 0)
h->plt.refcount = 1;
else
h->plt.refcount += 1;
}
}
}
if (h->plt.refcount <= 0)
{
h->plt.offset = (bfd_vma) -1;
h->needs_plt = 0;
}
return TRUE;
}
/* 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->needs_plt)
{
if (h->plt.refcount <= 0
|| SYMBOL_CALLS_LOCAL (info, h)
|| (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
&& h->root.type == bfd_link_hash_undefweak))
{
/* 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->needs_plt = 0;
}
return TRUE;
}
else
/* It's possible that we incorrectly decided a .plt reloc was
needed for an R_386_PC32 reloc to a non-function sym in
check_relocs. We can't decide accurately between function and
non-function syms in check-relocs; Objects loaded later in
the link may change h->type. So fix it now. */
h->plt.offset = (bfd_vma) -1;
/* 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->u.weakdef != NULL)
{
BFD_ASSERT (h->u.weakdef->root.type == bfd_link_hash_defined
|| h->u.weakdef->root.type == bfd_link_hash_defweak);
h->root.u.def.section = h->u.weakdef->root.u.def.section;
h->root.u.def.value = h->u.weakdef->root.u.def.value;
if (ELIMINATE_COPY_RELOCS || info->nocopyreloc)
h->non_got_ref = h->u.weakdef->non_got_ref;
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 (!bfd_link_executable (info))
return TRUE;
/* If there are no references to this symbol that do not use the
GOT nor R_386_GOTOFF relocation, we don't need to generate a copy
reloc. */
eh = (struct elf_i386_link_hash_entry *) h;
if (!h->non_got_ref && !eh->gotoff_ref)
return TRUE;
/* If -z nocopyreloc was given, we won't generate them either. */
if (info->nocopyreloc)
{
h->non_got_ref = 0;
return TRUE;
}
htab = elf_i386_hash_table (info);
if (htab == NULL)
return FALSE;
/* If there aren't any dynamic relocs in read-only sections nor
R_386_GOTOFF relocation, then we can keep the dynamic relocs and
avoid the copy reloc. This doesn't work on VxWorks, where we can
not have dynamic relocations (other than copy and jump slot
relocations) in an executable. */
if (ELIMINATE_COPY_RELOCS
&& !eh->gotoff_ref
&& !get_elf_i386_backend_data (info->output_bfd)->is_vxworks)
{
for (p = eh->dyn_relocs; p != NULL; p = p->next)
{
s = p->sec->output_section;
if (s != NULL && (s->flags & SEC_READONLY) != 0)
break;
}
if (p == NULL)
{
h->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. */
/* 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. */
if ((h->root.u.def.section->flags & SEC_ALLOC) != 0 && h->size != 0)
{
htab->srelbss->size += sizeof (Elf32_External_Rel);
h->needs_copy = 1;
}
s = htab->sdynbss;
return _bfd_elf_adjust_dynamic_copy (info, h, s);
}
/* Allocate space in .plt, .got and associated reloc sections for
dynamic relocs. */
static bfd_boolean
elf_i386_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
{
struct bfd_link_info *info;
struct elf_i386_link_hash_table *htab;
struct elf_i386_link_hash_entry *eh;
struct elf_dyn_relocs *p;
unsigned plt_entry_size;
bfd_boolean resolved_to_zero;
if (h->root.type == bfd_link_hash_indirect)
return TRUE;
eh = (struct elf_i386_link_hash_entry *) h;
info = (struct bfd_link_info *) inf;
htab = elf_i386_hash_table (info);
if (htab == NULL)
return FALSE;
plt_entry_size = GET_PLT_ENTRY_SIZE (info->output_bfd);
resolved_to_zero = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info,
eh->has_got_reloc,
eh);
/* Clear the reference count of function pointer relocations if
symbol isn't a normal function. */
if (h->type != STT_FUNC)
eh->func_pointer_refcount = 0;
/* We can't use the GOT PLT if pointer equality is needed since
finish_dynamic_symbol won't clear symbol value and the dynamic
linker won't update the GOT slot. We will get into an infinite
loop at run-time. */
if (htab->plt_got != NULL
&& h->type != STT_GNU_IFUNC
&& !h->pointer_equality_needed
&& h->plt.refcount > 0
&& h->got.refcount > 0)
{
/* Don't use the regular PLT if there are both GOT and GOTPLT
reloctions. */
h->plt.offset = (bfd_vma) -1;
/* Use the GOT PLT. */
eh->plt_got.refcount = 1;
}
/* Since STT_GNU_IFUNC symbol must go through PLT, we handle it
here if it is defined and referenced in a non-shared object. */
if (h->type == STT_GNU_IFUNC
&& h->def_regular)
return _bfd_elf_allocate_ifunc_dyn_relocs (info, h, &eh->dyn_relocs,
&htab->readonly_dynrelocs_against_ifunc,
plt_entry_size,
plt_entry_size, 4, TRUE);
/* Don't create the PLT entry if there are only function pointer
relocations which can be resolved at run-time. */
else if (htab->elf.dynamic_sections_created
&& (h->plt.refcount > eh->func_pointer_refcount
|| eh->plt_got.refcount > 0))
{
bfd_boolean use_plt_got;
/* Clear the reference count of function pointer relocations
if PLT is used. */
eh->func_pointer_refcount = 0;
if ((info->flags & DF_BIND_NOW) && !h->pointer_equality_needed)
{
/* Don't use the regular PLT for DF_BIND_NOW. */
h->plt.offset = (bfd_vma) -1;
/* Use the GOT PLT. */
h->got.refcount = 1;
eh->plt_got.refcount = 1;
}
use_plt_got = eh->plt_got.refcount > 0;
/* Make sure this symbol is output as a dynamic symbol.
Undefined weak syms won't yet be marked as dynamic. */
if (h->dynindx == -1
&& !h->forced_local
&& !resolved_to_zero)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
}
if (bfd_link_pic (info)
|| WILL_CALL_FINISH_DYNAMIC_SYMBOL (1, 0, h))
{
asection *s = htab->elf.splt;
asection *got_s = htab->plt_got;
/* If this is the first .plt entry, make room for the special
first entry. The .plt section is used by prelink to undo
prelinking for dynamic relocations. */
if (s->size == 0)
s->size = plt_entry_size;
if (use_plt_got)
eh->plt_got.offset = got_s->size;
else
h->plt.offset = s->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 (! bfd_link_pic (info)
&& !h->def_regular)
{
if (use_plt_got)
{
/* We need to make a call to the entry of the GOT PLT
instead of regular PLT entry. */
h->root.u.def.section = got_s;
h->root.u.def.value = eh->plt_got.offset;
}
else
{
h->root.u.def.section = s;
h->root.u.def.value = h->plt.offset;
}
}
/* Make room for this entry. */
if (use_plt_got)
got_s->size += sizeof (elf_i386_got_plt_entry);
else
{
s->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. */
htab->elf.sgotplt->size += 4;
/* There should be no PLT relocation against resolved
undefined weak symbol in executable. */
if (!resolved_to_zero)
{
/* We also need to make an entry in the .rel.plt
section. */
htab->elf.srelplt->size += sizeof (Elf32_External_Rel);
htab->elf.srelplt->reloc_count++;
}
}
if (get_elf_i386_backend_data (info->output_bfd)->is_vxworks
&& !bfd_link_pic (info))
{
/* VxWorks has a second set of relocations for each PLT entry
in executables. They go in a separate relocation section,
which is processed by the kernel loader. */
/* There are two relocations for the initial PLT entry: an
R_386_32 relocation for _GLOBAL_OFFSET_TABLE_ + 4 and an
R_386_32 relocation for _GLOBAL_OFFSET_TABLE_ + 8. */
if (h->plt.offset == plt_entry_size)
htab->srelplt2->size += (sizeof (Elf32_External_Rel) * 2);
/* There are two extra relocations for each subsequent PLT entry:
an R_386_32 relocation for the GOT entry, and an R_386_32
relocation for the PLT entry. */
htab->srelplt2->size += (sizeof (Elf32_External_Rel) * 2);
}
}
else
{
eh->plt_got.offset = (bfd_vma) -1;
h->plt.offset = (bfd_vma) -1;
h->needs_plt = 0