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gnu / binutils-gdb / b7ee8ec914c612587b080e9ad416315307f094fd / . / bfd / elfxx-x86.c
blob: dd951b91f50281cd4db32a5bd554f42bfea055ef [file] [log] [blame]
/* x86 specific support for ELF
Copyright (C) 2017-2024 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 "elfxx-x86.h"
#include "elf-vxworks.h"
#include "objalloc.h"
/* The name of the dynamic interpreter. This is put in the .interp
section. */
#define ELF32_DYNAMIC_INTERPRETER "/usr/lib/libc.so.1"
#define ELF64_DYNAMIC_INTERPRETER "/lib/ld64.so.1"
#define ELFX32_DYNAMIC_INTERPRETER "/lib/ldx32.so.1"
bool
_bfd_x86_elf_mkobject (bfd *abfd)
{
return bfd_elf_allocate_object (abfd,
sizeof (struct elf_x86_obj_tdata),
get_elf_backend_data (abfd)->target_id);
}
/* _TLS_MODULE_BASE_ needs to be treated especially when linking
executables. Rather than setting it to the beginning of the TLS
section, we have to set it to the end. This function may be called
multiple times, it is idempotent. */
void
_bfd_x86_elf_set_tls_module_base (struct bfd_link_info *info)
{
struct elf_x86_link_hash_table *htab;
struct bfd_link_hash_entry *base;
const struct elf_backend_data *bed;
if (!bfd_link_executable (info))
return;
bed = get_elf_backend_data (info->output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return;
base = htab->tls_module_base;
if (base == NULL)
return;
base->u.def.value = htab->elf.tls_size;
}
/* Return the base VMA address which should be subtracted from real addresses
when resolving @dtpoff relocation.
This is PT_TLS segment p_vaddr. */
bfd_vma
_bfd_x86_elf_dtpoff_base (struct bfd_link_info *info)
{
/* If tls_sec is NULL, we should have signalled an error already. */
if (elf_hash_table (info)->tls_sec == NULL)
return 0;
return elf_hash_table (info)->tls_sec->vma;
}
/* Allocate space in .plt, .got and associated reloc sections for
dynamic relocs. */
static bool
elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
{
struct bfd_link_info *info;
struct elf_x86_link_hash_table *htab;
struct elf_x86_link_hash_entry *eh;
struct elf_dyn_relocs *p;
unsigned int plt_entry_size;
bool resolved_to_zero;
const struct elf_backend_data *bed;
if (h->root.type == bfd_link_hash_indirect)
return true;
eh = (struct elf_x86_link_hash_entry *) h;
info = (struct bfd_link_info *) inf;
bed = get_elf_backend_data (info->output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return false;
plt_entry_size = htab->plt.plt_entry_size;
resolved_to_zero = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
/* 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)
{
/* GOTOFF relocation needs PLT. */
if (eh->gotoff_ref)
h->plt.refcount = 1;
if (_bfd_elf_allocate_ifunc_dyn_relocs (info, h, &h->dyn_relocs,
plt_entry_size,
(htab->plt.has_plt0
* plt_entry_size),
htab->got_entry_size,
true))
{
asection *s = htab->plt_second;
if (h->plt.offset != (bfd_vma) -1 && s != NULL)
{
/* Use the second PLT section if it is created. */
eh->plt_second.offset = s->size;
/* Make room for this entry in the second PLT section. */
s->size += htab->non_lazy_plt->plt_entry_size;
}
return true;
}
else
return false;
}
/* 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 > 0
|| eh->plt_got.refcount > 0))
{
bool 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
&& h->root.type == bfd_link_hash_undefweak)
{
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 *second_s = htab->plt_second;
asection *got_s = htab->plt_got;
bool use_plt;
/* 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 = htab->plt.has_plt0 * plt_entry_size;
if (use_plt_got)
eh->plt_got.offset = got_s->size;
else
{
h->plt.offset = s->size;
if (second_s)
eh->plt_second.offset = second_s->size;
}
/* If this symbol is not defined in a regular file, and we are
generating PDE, then set the symbol to this location in the
.plt. This is required to make function pointers compare
as equal between PDE and the shared library.
NB: If PLT is PC-relative, we can use the .plt in PIE for
function address. */
if (h->def_regular)
use_plt = false;
else if (htab->pcrel_plt)
use_plt = ! bfd_link_dll (info);
else
use_plt = bfd_link_pde (info);
if (use_plt)
{
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
{
if (second_s)
{
/* We need to make a call to the entry of the
second PLT instead of regular PLT entry. */
h->root.u.def.section = second_s;
h->root.u.def.value = eh->plt_second.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 += htab->non_lazy_plt->plt_entry_size;
else
{
s->size += plt_entry_size;
if (second_s)
second_s->size += htab->non_lazy_plt->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 += htab->got_entry_size;
/* 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 += htab->sizeof_reloc;
htab->elf.srelplt->reloc_count++;
}
}
if (htab->elf.target_os == 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. */
asection *srelplt2 = htab->srelplt2;
if (h->plt.offset == plt_entry_size)
srelplt2->size += (htab->sizeof_reloc * 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. */
srelplt2->size += (htab->sizeof_reloc * 2);
}
}
else
{
eh->plt_got.offset = (bfd_vma) -1;
h->plt.offset = (bfd_vma) -1;
h->needs_plt = 0;
}
}
else
{
eh->plt_got.offset = (bfd_vma) -1;
h->plt.offset = (bfd_vma) -1;
h->needs_plt = 0;
}
eh->tlsdesc_got = (bfd_vma) -1;
/* For i386, if R_386_TLS_{IE_32,IE,GOTIE} symbol is now local to the
binary, make it a R_386_TLS_LE_32 requiring no TLS entry. For
x86-64, if R_X86_64_GOTTPOFF symbol is now local to the binary,
make it a R_X86_64_TPOFF32 requiring no GOT entry. */
if (h->got.refcount > 0
&& bfd_link_executable (info)
&& h->dynindx == -1
&& (elf_x86_hash_entry (h)->tls_type & GOT_TLS_IE))
h->got.offset = (bfd_vma) -1;
else if (h->got.refcount > 0)
{
asection *s;
bool dyn;
int tls_type = elf_x86_hash_entry (h)->tls_type;
/* 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
&& h->root.type == bfd_link_hash_undefweak)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return false;
}
s = htab->elf.sgot;
if (GOT_TLS_GDESC_P (tls_type))
{
eh->tlsdesc_got = htab->elf.sgotplt->size
- elf_x86_compute_jump_table_size (htab);
htab->elf.sgotplt->size += 2 * htab->got_entry_size;
h->got.offset = (bfd_vma) -2;
}
if (! GOT_TLS_GDESC_P (tls_type)
|| GOT_TLS_GD_P (tls_type))
{
h->got.offset = s->size;
s->size += htab->got_entry_size;
/* R_386_TLS_GD and R_X86_64_TLSGD need 2 consecutive GOT
slots. */
if (GOT_TLS_GD_P (tls_type) || tls_type == GOT_TLS_IE_BOTH)
s->size += htab->got_entry_size;
}
dyn = htab->elf.dynamic_sections_created;
/* R_386_TLS_IE_32 needs one dynamic relocation,
R_386_TLS_IE resp. R_386_TLS_GOTIE needs one dynamic relocation,
(but if both R_386_TLS_IE_32 and R_386_TLS_IE is present, we
need two), R_386_TLS_GD and R_X86_64_TLSGD need one if local
symbol and two if global. No dynamic relocation against
resolved undefined weak symbol in executable. No dynamic
relocation against non-preemptible absolute symbol. */
if (tls_type == GOT_TLS_IE_BOTH)
htab->elf.srelgot->size += 2 * htab->sizeof_reloc;
else if ((GOT_TLS_GD_P (tls_type) && h->dynindx == -1)
|| (tls_type & GOT_TLS_IE))
htab->elf.srelgot->size += htab->sizeof_reloc;
else if (GOT_TLS_GD_P (tls_type))
htab->elf.srelgot->size += 2 * htab->sizeof_reloc;
else if (! GOT_TLS_GDESC_P (tls_type)
&& ((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
&& !resolved_to_zero)
|| h->root.type != bfd_link_hash_undefweak)
&& ((bfd_link_pic (info)
&& !(h->dynindx == -1
&& ABS_SYMBOL_P (h)))
|| WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, 0, h)))
htab->elf.srelgot->size += htab->sizeof_reloc;
if (GOT_TLS_GDESC_P (tls_type))
{
htab->elf.srelplt->size += htab->sizeof_reloc;
if (bed->target_id == X86_64_ELF_DATA)
htab->elf.tlsdesc_plt = (bfd_vma) -1;
}
}
else
h->got.offset = (bfd_vma) -1;
if (h->dyn_relocs == NULL)
return true;
/* In the shared -Bsymbolic case, discard space allocated for
dynamic pc-relative relocs against symbols which turn out to be
defined in regular objects. For the normal shared case, discard
space for pc-relative relocs that have become local due to symbol
visibility changes. */
if (bfd_link_pic (info))
{
/* Relocs that use pc_count are those that appear on a call
insn, or certain REL relocs that can generated via assembly.
We want calls to protected symbols to resolve directly to the
function rather than going via the plt. If people want
function pointer comparisons to work as expected then they
should avoid writing weird assembly. */
if (SYMBOL_CALLS_LOCAL (info, h))
{
struct elf_dyn_relocs **pp;
for (pp = &h->dyn_relocs; (p = *pp) != NULL; )
{
p->count -= p->pc_count;
p->pc_count = 0;
if (p->count == 0)
*pp = p->next;
else
pp = &p->next;
}
}
if (htab->elf.target_os == is_vxworks)
{
struct elf_dyn_relocs **pp;
for (pp = &h->dyn_relocs; (p = *pp) != NULL; )
{
if (strcmp (p->sec->output_section->name, ".tls_vars") == 0)
*pp = p->next;
else
pp = &p->next;
}
}
/* Also discard relocs on undefined weak syms with non-default
visibility or in PIE. */
if (h->dyn_relocs != NULL)
{
if (h->root.type == bfd_link_hash_undefweak)
{
/* Undefined weak symbol is never bound locally in shared
library. */
if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
|| resolved_to_zero)
{
if (bed->target_id == I386_ELF_DATA
&& h->non_got_ref)
{
/* Keep dynamic non-GOT/non-PLT relocation so
that we can branch to 0 without PLT. */
struct elf_dyn_relocs **pp;
for (pp = &h->dyn_relocs; (p = *pp) != NULL; )
if (p->pc_count == 0)
*pp = p->next;
else
{
/* Remove non-R_386_PC32 relocation. */
p->count = p->pc_count;
pp = &p->next;
}
/* Make sure undefined weak symbols are output
as dynamic symbols in PIEs for dynamic non-GOT
non-PLT reloations. */
if (h->dyn_relocs != NULL
&& !bfd_elf_link_record_dynamic_symbol (info, h))
return false;
}
else
h->dyn_relocs = NULL;
}
else if (h->dynindx == -1
&& !h->forced_local
&& !bfd_elf_link_record_dynamic_symbol (info, h))
return false;
}
else if (bfd_link_executable (info)
&& (h->needs_copy || eh->needs_copy)
&& h->def_dynamic
&& !h->def_regular)
{
/* NB: needs_copy is set only for x86-64. For PIE,
discard space for pc-relative relocs against symbols
which turn out to need copy relocs. */
struct elf_dyn_relocs **pp;
for (pp = &h->dyn_relocs; (p = *pp) != NULL; )
{
if (p->pc_count != 0)
*pp = p->next;
else
pp = &p->next;
}
}
}
}
else if (ELIMINATE_COPY_RELOCS)
{
/* For the non-shared case, discard space for relocs against
symbols which turn out to need copy relocs or are not
dynamic. Keep dynamic relocations for run-time function
pointer initialization. */
if ((!h->non_got_ref
|| (h->root.type == bfd_link_hash_undefweak
&& !resolved_to_zero))
&& ((h->def_dynamic
&& !h->def_regular)
|| (htab->elf.dynamic_sections_created
&& (h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_undefined))))
{
/* 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
&& h->root.type == bfd_link_hash_undefweak
&& ! bfd_elf_link_record_dynamic_symbol (info, h))
return false;
/* If that succeeded, we know we'll be keeping all the
relocs. */
if (h->dynindx != -1)
goto keep;
}
h->dyn_relocs = NULL;
keep: ;
}
/* Finally, allocate space. */
for (p = h->dyn_relocs; p != NULL; p = p->next)
{
asection *sreloc;
if (eh->def_protected && bfd_link_executable (info))
{
/* Disallow copy relocation against non-copyable protected
symbol. */
asection *s = p->sec->output_section;
if (s != NULL && (s->flags & SEC_READONLY) != 0)
{
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: copy relocation against non-copyable "
"protected symbol `%s' in %pB\n"),
p->sec->owner, h->root.root.string,
h->root.u.def.section->owner);
return false;
}
}
sreloc = elf_section_data (p->sec)->sreloc;
BFD_ASSERT (sreloc != NULL);
sreloc->size += p->count * htab->sizeof_reloc;
}
return true;
}
/* Allocate space in .plt, .got and associated reloc sections for
local dynamic relocs. */
static int
elf_x86_allocate_local_dynreloc (void **slot, void *inf)
{
struct elf_link_hash_entry *h
= (struct elf_link_hash_entry *) *slot;
if (h->type != STT_GNU_IFUNC
|| !h->def_regular
|| !h->ref_regular
|| !h->forced_local
|| h->root.type != bfd_link_hash_defined)
abort ();
return elf_x86_allocate_dynrelocs (h, inf);
}
/* Find and/or create a hash entry for local symbol. */
struct elf_link_hash_entry *
_bfd_elf_x86_get_local_sym_hash (struct elf_x86_link_hash_table *htab,
bfd *abfd, const Elf_Internal_Rela *rel,
bool create)
{
struct elf_x86_link_hash_entry e, *ret;
asection *sec = abfd->sections;
hashval_t h = ELF_LOCAL_SYMBOL_HASH (sec->id,
htab->r_sym (rel->r_info));
void **slot;
e.elf.indx = sec->id;
e.elf.dynstr_index = htab->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_x86_link_hash_entry *) *slot;
return &ret->elf;
}
ret = (struct elf_x86_link_hash_entry *)
objalloc_alloc ((struct objalloc *) htab->loc_hash_memory,
sizeof (struct elf_x86_link_hash_entry));
if (ret)
{
memset (ret, 0, sizeof (*ret));
ret->elf.indx = sec->id;
ret->elf.dynstr_index = htab->r_sym (rel->r_info);
ret->elf.dynindx = -1;
ret->plt_got.offset = (bfd_vma) -1;
*slot = ret;
}
return &ret->elf;
}
/* Create an entry in a x86 ELF linker hash table. NB: THIS MUST BE IN
SYNC WITH _bfd_elf_link_hash_newfunc. */
struct bfd_hash_entry *
_bfd_x86_elf_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_x86_link_hash_entry));
if (entry == NULL)
return entry;
}
/* Call the allocation method of the superclass. */
entry = _bfd_link_hash_newfunc (entry, table, string);
if (entry != NULL)
{
struct elf_x86_link_hash_entry *eh
= (struct elf_x86_link_hash_entry *) entry;
struct elf_link_hash_table *htab
= (struct elf_link_hash_table *) table;
memset (&eh->elf.size, 0,
(sizeof (struct elf_x86_link_hash_entry)
- offsetof (struct elf_link_hash_entry, size)));
/* Set local fields. */
eh->elf.indx = -1;
eh->elf.dynindx = -1;
eh->elf.got = htab->init_got_refcount;
eh->elf.plt = htab->init_plt_refcount;
/* Assume that we have been called by a non-ELF symbol reader.
This flag is then reset by the code which reads an ELF input
file. This ensures that a symbol created by a non-ELF symbol
reader will have the flag set correctly. */
eh->elf.non_elf = 1;
eh->plt_second.offset = (bfd_vma) -1;
eh->plt_got.offset = (bfd_vma) -1;
eh->tlsdesc_got = (bfd_vma) -1;
eh->zero_undefweak = 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. */
hashval_t
_bfd_x86_elf_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. */
int
_bfd_x86_elf_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;
}
/* Destroy an x86 ELF linker hash table. */
static void
elf_x86_link_hash_table_free (bfd *obfd)
{
struct elf_x86_link_hash_table *htab
= (struct elf_x86_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);
}
static bool
elf_i386_is_reloc_section (const char *secname)
{
return startswith (secname, ".rel");
}
static bool
elf_x86_64_is_reloc_section (const char *secname)
{
return startswith (secname, ".rela");
}
/* Create an x86 ELF linker hash table. */
struct bfd_link_hash_table *
_bfd_x86_elf_link_hash_table_create (bfd *abfd)
{
struct elf_x86_link_hash_table *ret;
const struct elf_backend_data *bed;
size_t amt = sizeof (struct elf_x86_link_hash_table);
ret = (struct elf_x86_link_hash_table *) bfd_zmalloc (amt);
if (ret == NULL)
return NULL;
bed = get_elf_backend_data (abfd);
if (!_bfd_elf_link_hash_table_init (&ret->elf, abfd,
_bfd_x86_elf_link_hash_newfunc,
sizeof (struct elf_x86_link_hash_entry),
bed->target_id))
{
free (ret);
return NULL;
}
if (bed->target_id == X86_64_ELF_DATA)
{
ret->is_reloc_section = elf_x86_64_is_reloc_section;
ret->got_entry_size = 8;
ret->pcrel_plt = true;
ret->tls_get_addr = "__tls_get_addr";
ret->relative_r_type = R_X86_64_RELATIVE;
ret->relative_r_name = "R_X86_64_RELATIVE";
ret->ax_register = "RAX";
ret->elf_append_reloc = elf_append_rela;
ret->elf_write_addend_in_got = _bfd_elf64_write_addend;
}
if (ABI_64_P (abfd))
{
ret->sizeof_reloc = sizeof (Elf64_External_Rela);
ret->pointer_r_type = R_X86_64_64;
ret->dynamic_interpreter = ELF64_DYNAMIC_INTERPRETER;
ret->dynamic_interpreter_size = sizeof ELF64_DYNAMIC_INTERPRETER;
ret->elf_write_addend = _bfd_elf64_write_addend;
}
else
{
if (bed->target_id == X86_64_ELF_DATA)
{
ret->sizeof_reloc = sizeof (Elf32_External_Rela);
ret->pointer_r_type = R_X86_64_32;
ret->dynamic_interpreter = ELFX32_DYNAMIC_INTERPRETER;
ret->dynamic_interpreter_size
= sizeof ELFX32_DYNAMIC_INTERPRETER;
ret->elf_write_addend = _bfd_elf32_write_addend;
}
else
{
ret->is_reloc_section = elf_i386_is_reloc_section;
ret->sizeof_reloc = sizeof (Elf32_External_Rel);
ret->got_entry_size = 4;
ret->pcrel_plt = false;
ret->pointer_r_type = R_386_32;
ret->relative_r_type = R_386_RELATIVE;
ret->relative_r_name = "R_386_RELATIVE";
ret->ax_register = "EAX";
ret->elf_append_reloc = elf_append_rel;
ret->elf_write_addend = _bfd_elf32_write_addend;
ret->elf_write_addend_in_got = _bfd_elf32_write_addend;
ret->dynamic_interpreter = ELF32_DYNAMIC_INTERPRETER;
ret->dynamic_interpreter_size
= sizeof ELF32_DYNAMIC_INTERPRETER;
ret->tls_get_addr = "___tls_get_addr";
}
}
ret->loc_hash_table = htab_try_create (1024,
_bfd_x86_elf_local_htab_hash,
_bfd_x86_elf_local_htab_eq,
NULL);
ret->loc_hash_memory = objalloc_create ();
if (!ret->loc_hash_table || !ret->loc_hash_memory)
{
elf_x86_link_hash_table_free (abfd);
return NULL;
}
ret->elf.root.hash_table_free = elf_x86_link_hash_table_free;
return &ret->elf.root;
}
/* Sort relocs into address order. */
int
_bfd_x86_elf_compare_relocs (const void *ap, const void *bp)
{
const arelent *a = * (const arelent **) ap;
const arelent *b = * (const arelent **) bp;
if (a->address > b->address)
return 1;
else if (a->address < b->address)
return -1;
else
return 0;
}
/* Mark symbol, NAME, as locally defined by linker if it is referenced
and not defined in a relocatable object file. */
static void
elf_x86_linker_defined (struct bfd_link_info *info, const char *name)
{
struct elf_link_hash_entry *h;
h = elf_link_hash_lookup (elf_hash_table (info), name,
false, false, false);
if (h == NULL)
return;
while (h->root.type == bfd_link_hash_indirect)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
if (h->root.type == bfd_link_hash_new
|| h->root.type == bfd_link_hash_undefined
|| h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_common
|| (!h->def_regular && h->def_dynamic))
{
elf_x86_hash_entry (h)->local_ref = 2;
elf_x86_hash_entry (h)->linker_def = 1;
}
}
/* Hide a linker-defined symbol, NAME, with hidden visibility. */
static void
elf_x86_hide_linker_defined (struct bfd_link_info *info,
const char *name)
{
struct elf_link_hash_entry *h;
h = elf_link_hash_lookup (elf_hash_table (info), name,
false, false, false);
if (h == NULL)
return;
while (h->root.type == bfd_link_hash_indirect)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
if (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL
|| ELF_ST_VISIBILITY (h->other) == STV_HIDDEN)
_bfd_elf_link_hash_hide_symbol (info, h, true);
}
bool
_bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
{
if (!bfd_link_relocatable (info))
{
/* Check for __tls_get_addr reference. */
struct elf_x86_link_hash_table *htab;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab)
{
struct elf_link_hash_entry *h;
h = elf_link_hash_lookup (elf_hash_table (info),
htab->tls_get_addr,
false, false, false);
if (h != NULL)
{
elf_x86_hash_entry (h)->tls_get_addr = 1;
/* Check the versioned __tls_get_addr symbol. */
while (h->root.type == bfd_link_hash_indirect)
{
h = (struct elf_link_hash_entry *) h->root.u.i.link;
elf_x86_hash_entry (h)->tls_get_addr = 1;
}
}
/* "__ehdr_start" will be defined by linker as a hidden symbol
later if it is referenced and not defined. */
elf_x86_linker_defined (info, "__ehdr_start");
if (bfd_link_executable (info))
{
/* References to __bss_start, _end and _edata should be
locally resolved within executables. */
elf_x86_linker_defined (info, "__bss_start");
elf_x86_linker_defined (info, "_end");
elf_x86_linker_defined (info, "_edata");
}
else
{
/* Hide hidden __bss_start, _end and _edata in shared
libraries. */
elf_x86_hide_linker_defined (info, "__bss_start");
elf_x86_hide_linker_defined (info, "_end");
elf_x86_hide_linker_defined (info, "_edata");
}
}
}
/* Invoke the regular ELF backend linker to do all the work. */
return _bfd_elf_link_check_relocs (abfd, info);
}
/* Look through the relocs for a section before allocation to make the
dynamic reloc section. */
bool
_bfd_x86_elf_check_relocs (bfd *abfd,
struct bfd_link_info *info,
asection *sec,
const Elf_Internal_Rela *relocs)
{
struct elf_x86_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;
const struct elf_backend_data *bed;
bool is_x86_64;
if (bfd_link_relocatable (info))
return true;
bed = get_elf_backend_data (abfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
{
sec->check_relocs_failed = 1;
return false;
}
is_x86_64 = bed->target_id == X86_64_ELF_DATA;
symtab_hdr = &elf_symtab_hdr (abfd);
sym_hashes = elf_sym_hashes (abfd);
rel_end = relocs + sec->reloc_count;
for (rel = relocs; rel < rel_end; rel++)
{
unsigned int r_type;
unsigned int r_symndx;
struct elf_link_hash_entry *h;
r_symndx = htab->r_sym (rel->r_info);
r_type = ELF32_R_TYPE (rel->r_info);
if (r_symndx >= NUM_SHDR_ENTRIES (symtab_hdr))
{
/* xgettext:c-format */
_bfd_error_handler (_("%pB: bad symbol index: %d"),
abfd, r_symndx);
goto error_return;
}
if (r_symndx < symtab_hdr->sh_info)
h = NULL;
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 (X86_NEED_DYNAMIC_RELOC_TYPE_P (is_x86_64, r_type)
&& NEED_DYNAMIC_RELOCATION_P (is_x86_64, info, true, h, sec,
r_type, htab->pointer_r_type))
{
/* We may copy these reloc types into the output file.
Create a reloc section in dynobj and make room for
this reloc. */
sreloc = _bfd_elf_make_dynamic_reloc_section
(sec, htab->elf.dynobj, ABI_64_P (abfd) ? 3 : 2,
abfd, sec->use_rela_p);
if (sreloc != NULL)
return true;
error_return:
sec->check_relocs_failed = 1;
return false;
}
}
return true;
}
/* Add an entry to the relative reloc record. */
static bool
elf_x86_relative_reloc_record_add
(struct bfd_link_info *info,
struct elf_x86_relative_reloc_data *relative_reloc,
Elf_Internal_Rela *rel, asection *sec,
asection *sym_sec, struct elf_link_hash_entry *h,
Elf_Internal_Sym *sym, bfd_vma offset, bool *keep_symbuf_p)
{
bfd_size_type newidx;
if (relative_reloc->data == NULL)
{
relative_reloc->data = bfd_malloc
(sizeof (struct elf_x86_relative_reloc_record));
relative_reloc->count = 0;
relative_reloc->size = 1;
}
newidx = relative_reloc->count++;
if (relative_reloc->count > relative_reloc->size)
{
relative_reloc->size <<= 1;
relative_reloc->data = bfd_realloc
(relative_reloc->data,
(relative_reloc->size
* sizeof (struct elf_x86_relative_reloc_record)));
}
if (relative_reloc->data == NULL)
{
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: failed to allocate relative reloc record\n"),
info->output_bfd);
return false;
}
relative_reloc->data[newidx].rel = *rel;
relative_reloc->data[newidx].sec = sec;
if (h != NULL)
{
/* Set SYM to NULL to indicate a global symbol. */
relative_reloc->data[newidx].sym = NULL;
relative_reloc->data[newidx].u.h = h;
}
else
{
relative_reloc->data[newidx].sym = sym;
relative_reloc->data[newidx].u.sym_sec = sym_sec;
/* We must keep the symbol buffer since SYM will be used later. */
*keep_symbuf_p = true;
}
relative_reloc->data[newidx].offset = offset;
relative_reloc->data[newidx].address = 0;
return true;
}
/* After input sections have been mapped to output sections and
addresses of output sections are set initiallly, scan input
relocations with the same logic in relocate_section to determine
if a relative relocation should be generated. Save the relative
relocation candidate information for sizing the DT_RELR section
later after all symbols addresses can be determined. */
bool
_bfd_x86_elf_link_relax_section (bfd *abfd ATTRIBUTE_UNUSED,
asection *input_section,
struct bfd_link_info *info,
bool *again)
{
Elf_Internal_Shdr *symtab_hdr;
Elf_Internal_Rela *internal_relocs;
Elf_Internal_Rela *irel, *irelend;
Elf_Internal_Sym *isymbuf = NULL;
struct elf_link_hash_entry **sym_hashes;
const struct elf_backend_data *bed;
struct elf_x86_link_hash_table *htab;
bfd_vma *local_got_offsets;
bool is_x86_64;
bool unaligned_section;
bool return_status = false;
bool keep_symbuf = false;
if (bfd_link_relocatable (info))
return true;
/* Assume we're not going to change any sizes, and we'll only need
one pass. */
*again = false;
bed = get_elf_backend_data (abfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return true;
/* Nothing to do if there are no relocations or relative relocations
have been packed. */
if (input_section == htab->elf.srelrdyn
|| input_section->relative_reloc_packed
|| ((input_section->flags & (SEC_RELOC | SEC_ALLOC))
!= (SEC_RELOC | SEC_ALLOC))
|| (input_section->flags & SEC_DEBUGGING) != 0
|| input_section->reloc_count == 0)
return true;
/* Skip if the section isn't aligned. */
unaligned_section = input_section->alignment_power == 0;
is_x86_64 = bed->target_id == X86_64_ELF_DATA;
symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
sym_hashes = elf_sym_hashes (abfd);
local_got_offsets = elf_local_got_offsets (abfd);
/* Load the relocations for this section. */
internal_relocs =
_bfd_elf_link_info_read_relocs (abfd, info, input_section, NULL,
(Elf_Internal_Rela *) NULL,
info->keep_memory);
if (internal_relocs == NULL)
return false;
irelend = internal_relocs + input_section->reloc_count;
for (irel = internal_relocs; irel < irelend; irel++)
{
unsigned int r_type;
unsigned int r_symndx;
Elf_Internal_Sym *isym;
struct elf_link_hash_entry *h;
struct elf_x86_link_hash_entry *eh;
bfd_vma offset;
bool resolved_to_zero;
bool need_copy_reloc_in_pie;
bool pc32_reloc;
asection *sec;
/* Offset must be a multiple of 2. */
bool unaligned_offset = (irel->r_offset & 1) != 0;
/* True if there is a relative relocation against a dynamic
symbol. */
bool dynamic_relative_reloc_p;
/* Get the value of the symbol referred to by the reloc. */
r_symndx = htab->r_sym (irel->r_info);
r_type = ELF32_R_TYPE (irel->r_info);
/* Clear the R_X86_64_converted_reloc_bit bit. */
r_type &= ~R_X86_64_converted_reloc_bit;
sec = NULL;
h = NULL;
dynamic_relative_reloc_p = false;
if (r_symndx < symtab_hdr->sh_info)
{
/* Read this BFD's local symbols. */
if (isymbuf == NULL)
{
isymbuf = (Elf_Internal_Sym *) symtab_hdr->contents;
if (isymbuf == NULL)
{
isymbuf = bfd_elf_get_elf_syms (abfd, symtab_hdr,
symtab_hdr->sh_info,
0, NULL, NULL, NULL);
if (isymbuf == NULL)
goto error_return;
}
}
isym = isymbuf + r_symndx;
switch (isym->st_shndx)
{
case SHN_ABS:
sec = bfd_abs_section_ptr;
break;
case SHN_COMMON:
sec = bfd_com_section_ptr;
break;
case SHN_X86_64_LCOMMON:
if (!is_x86_64)
abort ();
sec = &_bfd_elf_large_com_section;
break;
default:
sec = bfd_section_from_elf_index (abfd, isym->st_shndx);
break;
}
/* Skip relocation against local STT_GNU_IFUNC symbol. */
if (ELF32_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
continue;
eh = (struct elf_x86_link_hash_entry *) h;
resolved_to_zero = false;
}
else
{
/* Get H and SEC for GENERATE_DYNAMIC_RELOCATION_P below. */
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;
/* Skip relocation against STT_GNU_IFUNC symbol. */
if (h->type == STT_GNU_IFUNC)
continue;
eh = (struct elf_x86_link_hash_entry *) h;
resolved_to_zero = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
/* NB: See how elf_backend_finish_dynamic_symbol is called
from elf_link_output_extsym. */
if ((h->dynindx != -1 || h->forced_local)
&& ((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
|| h->root.type != bfd_link_hash_undefweak)
|| !h->forced_local)
&& h->got.offset != (bfd_vma) -1
&& ! GOT_TLS_GD_ANY_P (elf_x86_hash_entry (h)->tls_type)
&& elf_x86_hash_entry (h)->tls_type != GOT_TLS_IE
&& !resolved_to_zero
&& SYMBOL_REFERENCES_LOCAL_P (info, h)
&& SYMBOL_DEFINED_NON_SHARED_P (h))
dynamic_relative_reloc_p = true;
isym = NULL;
}
if (X86_GOT_TYPE_P (is_x86_64, r_type))
{
/* Pack GOT relative relocations. There should be only a
single R_*_RELATIVE relocation in GOT. */
if (eh != NULL)
{
if (eh->got_relative_reloc_done)
continue;
if (!(dynamic_relative_reloc_p
|| (RESOLVED_LOCALLY_P (info, h, htab)
&& GENERATE_RELATIVE_RELOC_P (info, h))))
continue;
if (!dynamic_relative_reloc_p)
eh->no_finish_dynamic_symbol = 1;
eh->got_relative_reloc_done = 1;
offset = h->got.offset;
}
else
{
if (elf_x86_relative_reloc_done (abfd)[r_symndx])
continue;
if (!X86_LOCAL_GOT_RELATIVE_RELOC_P (is_x86_64, info,
isym))
continue;
elf_x86_relative_reloc_done (abfd)[r_symndx] = 1;
offset = local_got_offsets[r_symndx];
}
if (!elf_x86_relative_reloc_record_add (info,
&htab->relative_reloc,
irel, htab->elf.sgot,
sec, h, isym, offset,
&keep_symbuf))
goto error_return;
continue;
}
if (is_x86_64
&& irel->r_addend == 0
&& !ABI_64_P (info->output_bfd))
{
/* For x32, if addend is zero, treat R_X86_64_64 like
R_X86_64_32 and R_X86_64_SIZE64 like R_X86_64_SIZE32. */
if (r_type == R_X86_64_64)
r_type = R_X86_64_32;
else if (r_type == R_X86_64_SIZE64)
r_type = R_X86_64_SIZE32;
}
if (!X86_RELATIVE_RELOC_TYPE_P (is_x86_64, r_type))
continue;
/* Pack non-GOT relative relocations. */
if (is_x86_64)
{
need_copy_reloc_in_pie =
(bfd_link_pie (info)
&& h != NULL
&& (h->needs_copy
|| eh->needs_copy
|| (h->root.type == bfd_link_hash_undefined))
&& (X86_PCREL_TYPE_P (true, r_type)
|| X86_SIZE_TYPE_P (true, r_type)));
pc32_reloc = false;
}
else
{
need_copy_reloc_in_pie = false;
pc32_reloc = r_type == R_386_PC32;
}
if (GENERATE_DYNAMIC_RELOCATION_P (is_x86_64, info, eh, r_type,
sec, need_copy_reloc_in_pie,
resolved_to_zero, pc32_reloc))
{
/* When generating a shared object, these relocations
are copied into the output file to be resolved at run
time. */
offset = _bfd_elf_section_offset (info->output_bfd, info,
input_section,
irel->r_offset);
if (offset == (bfd_vma) -1
|| offset == (bfd_vma) -2
|| COPY_INPUT_RELOC_P (is_x86_64, info, h, r_type))
continue;
/* This symbol is local, or marked to become local. When
relocation overflow check is disabled, we convert
R_X86_64_32 to dynamic R_X86_64_RELATIVE. */
if (is_x86_64
&& !(r_type == htab->pointer_r_type
|| (r_type == R_X86_64_32
&& htab->params->no_reloc_overflow_check)))
continue;
if (!elf_x86_relative_reloc_record_add
(info,
((unaligned_section || unaligned_offset)
? &htab->unaligned_relative_reloc
: &htab->relative_reloc),
irel, input_section, sec, h, isym, offset,
&keep_symbuf))
goto error_return;
}
}
input_section->relative_reloc_packed = 1;
return_status = true;
error_return:
if ((unsigned char *) isymbuf != symtab_hdr->contents)
{
/* Cache the symbol buffer if it must be kept. */
if (keep_symbuf)
symtab_hdr->contents = (unsigned char *) isymbuf;
else
free (isymbuf);
}
if (elf_section_data (input_section)->relocs != internal_relocs)
free (internal_relocs);
return return_status;
}
/* Add an entry to the 64-bit DT_RELR bitmap. */
static void
elf64_dt_relr_bitmap_add
(struct bfd_link_info *info, struct elf_dt_relr_bitmap *bitmap,
uint64_t entry)
{
bfd_size_type newidx;
if (bitmap->u.elf64 == NULL)
{
bitmap->u.elf64 = bfd_malloc (sizeof (uint64_t));
bitmap->count = 0;
bitmap->size = 1;
}
newidx = bitmap->count++;
if (bitmap->count > bitmap->size)
{
bitmap->size <<= 1;
bitmap->u.elf64 = bfd_realloc (bitmap->u.elf64,
(bitmap->size * sizeof (uint64_t)));
}
if (bitmap->u.elf64 == NULL)
{
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: failed to allocate 64-bit DT_RELR bitmap\n"),
info->output_bfd);
}
bitmap->u.elf64[newidx] = entry;
}
/* Add an entry to the 32-bit DT_RELR bitmap. */
static void
elf32_dt_relr_bitmap_add
(struct bfd_link_info *info, struct elf_dt_relr_bitmap *bitmap,
uint32_t entry)
{
bfd_size_type newidx;
if (bitmap->u.elf32 == NULL)
{
bitmap->u.elf32 = bfd_malloc (sizeof (uint32_t));
bitmap->count = 0;
bitmap->size = 1;
}
newidx = bitmap->count++;
if (bitmap->count > bitmap->size)
{
bitmap->size <<= 1;
bitmap->u.elf32 = bfd_realloc (bitmap->u.elf32,
(bitmap->size * sizeof (uint32_t)));
}
if (bitmap->u.elf32 == NULL)
{
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: failed to allocate 32-bit DT_RELR bitmap\n"),
info->output_bfd);
}
bitmap->u.elf32[newidx] = entry;
}
void
_bfd_elf32_write_addend (bfd *abfd, uint64_t value, void *addr)
{
bfd_put_32 (abfd, value, addr);
}
void
_bfd_elf64_write_addend (bfd *abfd, uint64_t value, void *addr)
{
bfd_put_64 (abfd, value, addr);
}
/* Size or finish relative relocations to determine the run-time
addresses for DT_RELR bitmap computation later. OUTREL is set
to NULL in the sizing phase and non-NULL in the finising phase
where the regular relative relocations will be written out. */
static void
elf_x86_size_or_finish_relative_reloc
(bool is_x86_64, struct bfd_link_info *info,
struct elf_x86_link_hash_table *htab, bool unaligned,
Elf_Internal_Rela *outrel)
{
unsigned int align_mask;
bfd_size_type i, count;
asection *sec, *srel;
struct elf_link_hash_entry *h;
bfd_vma offset;
Elf_Internal_Sym *sym;
asection *sym_sec;
asection *sgot = htab->elf.sgot;
asection *srelgot = htab->elf.srelgot;
struct elf_x86_relative_reloc_data *relative_reloc;
if (unaligned)
{
align_mask = 0;
relative_reloc = &htab->unaligned_relative_reloc;
}
else
{
align_mask = 1;
relative_reloc = &htab->relative_reloc;
}
count = relative_reloc->count;
for (i = 0; i < count; i++)
{
sec = relative_reloc->data[i].sec;
sym = relative_reloc->data[i].sym;
/* If SYM is NULL, it must be a global symbol. */
if (sym == NULL)
h = relative_reloc->data[i].u.h;
else
h = NULL;
if (is_x86_64)
{
bfd_vma relocation;
/* This function may be called more than once and REL may be
updated by _bfd_elf_rela_local_sym below. */
Elf_Internal_Rela rel = relative_reloc->data[i].rel;
if (h != NULL)
{
if (h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
{
sym_sec = h->root.u.def.section;
relocation = (h->root.u.def.value
+ sym_sec->output_section->vma
+ sym_sec->output_offset);
}
else
{
/* Allow undefined symbol only at the sizing phase.
Otherwise skip undefined symbol here. Undefined
symbol will be reported by relocate_section. */
if (outrel == NULL)
relocation = 0;
else
continue;
}
}
else
{
sym_sec = relative_reloc->data[i].u.sym_sec;
relocation = _bfd_elf_rela_local_sym
(info->output_bfd, sym, &sym_sec, &rel);
}
if (outrel != NULL)
{
outrel->r_addend = relocation;
if (sec == sgot)
{
if (h != NULL && h->needs_plt)
abort ();
}
else
outrel->r_addend += rel.r_addend;
/* Write the implicit addend if ALIGN_MASK isn't 0. */
if (align_mask)
{
if (sec == sgot)
{
if (relative_reloc->data[i].offset >= sec->size)
abort ();
htab->elf_write_addend_in_got
(info->output_bfd, outrel->r_addend,
sec->contents + relative_reloc->data[i].offset);
}
else
{
bfd_byte *contents;
if (rel.r_offset >= sec->size)
abort ();
if (elf_section_data (sec)->this_hdr.contents
!= NULL)
contents
= elf_section_data (sec)->this_hdr.contents;
else
{
if (!_bfd_elf_mmap_section_contents (sec->owner,
sec,
&contents))
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: failed to allocate memory for section `%pA'\n"),
info->output_bfd, sec);
/* Cache the section contents for
elf_link_input_bfd. */
elf_section_data (sec)->this_hdr.contents
= contents;
}
htab->elf_write_addend
(info->output_bfd, outrel->r_addend,
contents + rel.r_offset);
}
}
}
}
if (sec == sgot)
srel = srelgot;
else
srel = elf_section_data (sec)->sreloc;
offset = (sec->output_section->vma + sec->output_offset
+ relative_reloc->data[i].offset);
relative_reloc->data[i].address = offset;
if (outrel != NULL)
{
outrel->r_offset = offset;
if ((outrel->r_offset & align_mask) != 0)
abort ();
if (htab->params->report_relative_reloc)
_bfd_x86_elf_link_report_relative_reloc
(info, sec, h, sym, htab->relative_r_name, outrel);
/* Generate regular relative relocation if ALIGN_MASK is 0. */
if (align_mask == 0)
htab->elf_append_reloc (info->output_bfd, srel, outrel);
}
}
}
/* Compute the DT_RELR section size. Set NEED_PLAYOUT to true if
the DT_RELR section size has been increased. */
static void
elf_x86_compute_dl_relr_bitmap
(struct bfd_link_info *info, struct elf_x86_link_hash_table *htab,
bool *need_layout)
{
bfd_vma base;
bfd_size_type i, count, new_count;
struct elf_x86_relative_reloc_data *relative_reloc =
&htab->relative_reloc;
/* Save the old DT_RELR bitmap count. Don't shrink the DT_RELR bitmap
if the new DT_RELR bitmap count is smaller than the old one. Pad
with trailing 1s which won't be decoded to more relocations. */
bfd_size_type dt_relr_bitmap_count = htab->dt_relr_bitmap.count;
/* Clear the DT_RELR bitmap count. */
htab->dt_relr_bitmap.count = 0;
count = relative_reloc->count;
if (ABI_64_P (info->output_bfd))
{
/* Compute the 64-bit DT_RELR bitmap. */
i = 0;
while (i < count)
{
if ((relative_reloc->data[i].address % 1) != 0)
abort ();
elf64_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap,
relative_reloc->data[i].address);
base = relative_reloc->data[i].address + 8;
i++;
while (i < count)
{
uint64_t bitmap = 0;
for (; i < count; i++)
{
bfd_vma delta = (relative_reloc->data[i].address
- base);
/* Stop if it is too far from base. */
if (delta >= 63 * 8)
break;
/* Stop if it isn't a multiple of 8. */
if ((delta % 8) != 0)
break;
bitmap |= 1ULL << (delta / 8);
}
if (bitmap == 0)
break;
elf64_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap,
(bitmap << 1) | 1);
base += 63 * 8;
}
}
new_count = htab->dt_relr_bitmap.count;
if (dt_relr_bitmap_count > new_count)
{
/* Don't shrink the DT_RELR section size to avoid section
layout oscillation. Instead, pad the DT_RELR bitmap with
1s which do not decode to more relocations. */
htab->dt_relr_bitmap.count = dt_relr_bitmap_count;
count = dt_relr_bitmap_count - new_count;
for (i = 0; i < count; i++)
htab->dt_relr_bitmap.u.elf64[new_count + i] = 1;
}
}
else
{
/* Compute the 32-bit DT_RELR bitmap. */
i = 0;
while (i < count)
{
if ((relative_reloc->data[i].address % 1) != 0)
abort ();
elf32_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap,
relative_reloc->data[i].address);
base = relative_reloc->data[i].address + 4;
i++;
while (i < count)
{
uint32_t bitmap = 0;
for (; i < count; i++)
{
bfd_vma delta = (relative_reloc->data[i].address
- base);
/* Stop if it is too far from base. */
if (delta >= 31 * 4)
break;
/* Stop if it isn't a multiple of 4. */
if ((delta % 4) != 0)
break;
bitmap |= 1ULL << (delta / 4);
}
if (bitmap == 0)
break;
elf32_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap,
(bitmap << 1) | 1);
base += 31 * 4;
}
}
new_count = htab->dt_relr_bitmap.count;
if (dt_relr_bitmap_count > new_count)
{
/* Don't shrink the DT_RELR section size to avoid section
layout oscillation. Instead, pad the DT_RELR bitmap with
1s which do not decode to more relocations. */
htab->dt_relr_bitmap.count = dt_relr_bitmap_count;
count = dt_relr_bitmap_count - new_count;
for (i = 0; i < count; i++)
htab->dt_relr_bitmap.u.elf32[new_count + i] = 1;
}
}
if (htab->dt_relr_bitmap.count != dt_relr_bitmap_count)
{
if (need_layout)
{
/* The .relr.dyn section size is changed. Update the section
size and tell linker to layout sections again. */
htab->elf.srelrdyn->size =
(htab->dt_relr_bitmap.count
* (ABI_64_P (info->output_bfd) ? 8 : 4));
*need_layout = true;
}
else
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: size of compact relative reloc section is "
"changed: new (%lu) != old (%lu)\n"),
info->output_bfd, htab->dt_relr_bitmap.count,
dt_relr_bitmap_count);
}
}
/* Write out the DT_RELR section. */
static void
elf_x86_write_dl_relr_bitmap (struct bfd_link_info *info,
struct elf_x86_link_hash_table *htab)
{
asection *sec = htab->elf.srelrdyn;
bfd_size_type size = sec->size;
bfd_size_type i;
unsigned char *contents;
contents = (unsigned char *) bfd_alloc (sec->owner, size);
if (contents == NULL)
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: failed to allocate compact relative reloc section\n"),
info->output_bfd);
/* Cache the section contents for elf_link_input_bfd. */
sec->contents = contents;
if (ABI_64_P (info->output_bfd))
for (i = 0; i < htab->dt_relr_bitmap.count; i++, contents += 8)
bfd_put_64 (info->output_bfd, htab->dt_relr_bitmap.u.elf64[i],
contents);
else
for (i = 0; i < htab->dt_relr_bitmap.count; i++, contents += 4)
bfd_put_32 (info->output_bfd, htab->dt_relr_bitmap.u.elf32[i],
contents);
}
/* Sort relative relocations by address. */
static int
elf_x86_relative_reloc_compare (const void *pa, const void *pb)
{
struct elf_x86_relative_reloc_record *a =
(struct elf_x86_relative_reloc_record *) pa;
struct elf_x86_relative_reloc_record *b =
(struct elf_x86_relative_reloc_record *) pb;
if (a->address < b->address)
return -1;
if (a->address > b->address)
return 1;
return 0;
}
enum dynobj_sframe_plt_type
{
SFRAME_PLT = 1,
SFRAME_PLT_SEC = 2
};
/* Create SFrame stack trace info for the plt entries in the .plt section
of type PLT_SEC_TYPE. */
static bool
_bfd_x86_elf_create_sframe_plt (bfd *output_bfd,
struct bfd_link_info *info,
unsigned int plt_sec_type)
{
struct elf_x86_link_hash_table *htab;
const struct elf_backend_data *bed;
bool plt0_generated_p;
unsigned int plt0_entry_size;
unsigned char func_info;
uint32_t fre_type;
/* The dynamic plt section for which .sframe stack trace information is being
created. */
asection *dpltsec;
int err = 0;
sframe_encoder_ctx **ectx = NULL;
unsigned plt_entry_size = 0;
unsigned int num_pltn_fres = 0;
unsigned int num_pltn_entries = 0;
bed = get_elf_backend_data (output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
/* Whether SFrame stack trace info for plt0 is to be generated. */
plt0_generated_p = htab->plt.has_plt0;
plt0_entry_size
= (plt0_generated_p) ? htab->sframe_plt->plt0_entry_size : 0;
switch (plt_sec_type)
{
case SFRAME_PLT:
{
ectx = &htab->plt_cfe_ctx;
dpltsec = htab->elf.splt;
plt_entry_size = htab->plt.plt_entry_size;
num_pltn_fres = htab->sframe_plt->pltn_num_fres;
num_pltn_entries
= (dpltsec->size - plt0_entry_size) / plt_entry_size;
break;
}
case SFRAME_PLT_SEC:
{
ectx = &htab->plt_second_cfe_ctx;
/* FIXME - this or htab->plt_second_sframe ? */
dpltsec = htab->plt_second_eh_frame;
plt_entry_size = htab->sframe_plt->sec_pltn_entry_size;
num_pltn_fres = htab->sframe_plt->sec_pltn_num_fres;
num_pltn_entries = dpltsec->size / plt_entry_size;
break;
}
default:
/* No other value is possible. */
return false;
break;
}
*ectx = sframe_encode (SFRAME_VERSION_2,
0,
SFRAME_ABI_AMD64_ENDIAN_LITTLE,
SFRAME_CFA_FIXED_FP_INVALID,
-8, /* Fixed RA offset. */
&err);
/* FRE type is dependent on the size of the function. */
fre_type = sframe_calc_fre_type (dpltsec->size);
func_info = sframe_fde_create_func_info (fre_type, SFRAME_FDE_TYPE_PCINC);
/* Add SFrame FDE and the associated FREs for plt0 if plt0 has been
generated. */
if (plt0_generated_p)
{
/* Add SFrame FDE for plt0, the function start address is updated later
at _bfd_elf_merge_section_sframe time. */
sframe_encoder_add_funcdesc_v2 (*ectx,
0, /* func start addr. */
plt0_entry_size,
func_info,
16,
0 /* Num FREs. */);
sframe_frame_row_entry plt0_fre;
unsigned int num_plt0_fres = htab->sframe_plt->plt0_num_fres;
for (unsigned int j = 0; j < num_plt0_fres; j++)
{
plt0_fre = *(htab->sframe_plt->plt0_fres[j]);
sframe_encoder_add_fre (*ectx, 0, &plt0_fre);
}
}
if (num_pltn_entries)
{
/* pltn entries use an SFrame FDE of type
SFRAME_FDE_TYPE_PCMASK to exploit the repetitive
pattern of the instructions in these entries. Using this SFrame FDE
type helps in keeping the SFrame stack trace info for pltn entries
compact. */
func_info = sframe_fde_create_func_info (fre_type,
SFRAME_FDE_TYPE_PCMASK);
/* Add the SFrame FDE for all PCs starting at the first pltn entry (hence,
function start address = plt0_entry_size. As usual, this will be
updated later at _bfd_elf_merge_section_sframe, by when the
sections are relocated. */
sframe_encoder_add_funcdesc_v2 (*ectx,
plt0_entry_size, /* func start addr. */
dpltsec->size - plt0_entry_size,
func_info,
16,
0 /* Num FREs. */);
sframe_frame_row_entry pltn_fre;
/* Now add the FREs for pltn. Simply adding the two FREs suffices due
to the usage of SFRAME_FDE_TYPE_PCMASK above. */
for (unsigned int j = 0; j < num_pltn_fres; j++)
{
pltn_fre = *(htab->sframe_plt->pltn_fres[j]);
sframe_encoder_add_fre (*ectx, 1, &pltn_fre);
}
}
return true;
}
/* Put contents of the .sframe section corresponding to the specified
PLT_SEC_TYPE. */
static bool
_bfd_x86_elf_write_sframe_plt (bfd *output_bfd,
struct bfd_link_info *info,
unsigned int plt_sec_type)
{
struct elf_x86_link_hash_table *htab;
const struct elf_backend_data *bed;
sframe_encoder_ctx *ectx;
size_t sec_size;
asection *sec;
bfd *dynobj;
int err = 0;
bed = get_elf_backend_data (output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
dynobj = htab->elf.dynobj;
switch (plt_sec_type)
{
case SFRAME_PLT:
ectx = htab->plt_cfe_ctx;
sec = htab->plt_sframe;
break;
case SFRAME_PLT_SEC:
ectx = htab->plt_second_cfe_ctx;
sec = htab->plt_second_sframe;
break;
default:
/* No other value is possible. */
return false;
break;
}
BFD_ASSERT (ectx);
void *contents = sframe_encoder_write (ectx, &sec_size, &err);
sec->size = (bfd_size_type) sec_size;
sec->contents = (unsigned char *) bfd_zalloc (dynobj, sec->size);
memcpy (sec->contents, contents, sec_size);
sframe_encoder_free (&ectx);
return true;
}
bool
_bfd_elf_x86_size_relative_relocs (struct bfd_link_info *info,
bool *need_layout)
{
struct elf_x86_link_hash_table *htab;
const struct elf_backend_data *bed;
bool is_x86_64;
bfd_size_type i, count, unaligned_count;
asection *sec, *srel;
/* Do nothing for ld -r. */
if (bfd_link_relocatable (info))
return true;
bed = get_elf_backend_data (info->output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return false;
count = htab->relative_reloc.count;
unaligned_count = htab->unaligned_relative_reloc.count;
if (count == 0)
{
if (htab->generate_relative_reloc_pass == 0
&& htab->elf.srelrdyn != NULL)
{
/* Remove the empty .relr.dyn sections now. */
if (!bfd_is_abs_section (htab->elf.srelrdyn->output_section))
{
bfd_section_list_remove
(info->output_bfd, htab->elf.srelrdyn->output_section);
info->output_bfd->section_count--;
}
bfd_section_list_remove (htab->elf.srelrdyn->owner,
htab->elf.srelrdyn);
htab->elf.srelrdyn->owner->section_count--;
}
if (unaligned_count == 0)
{
htab->generate_relative_reloc_pass++;
return true;
}
}
is_x86_64 = bed->target_id == X86_64_ELF_DATA;
/* Size relative relocations. */
if (htab->generate_relative_reloc_pass)
{
/* Reset the regular relative relocation count. */
for (i = 0; i < unaligned_count; i++)
{
sec = htab->unaligned_relative_reloc.data[i].sec;
srel = elf_section_data (sec)->sreloc;
srel->reloc_count = 0;
}
}
else
{
/* Remove the reserved space for compact relative relocations. */
if (count)
{
asection *sgot = htab->elf.sgot;
asection *srelgot = htab->elf.srelgot;
for (i = 0; i < count; i++)
{
sec = htab->relative_reloc.data[i].sec;
if (sec == sgot)
srel = srelgot;
else
srel = elf_section_data (sec)->sreloc;
srel->size -= htab->sizeof_reloc;
}
}
}
/* Size unaligned relative relocations. */
if (unaligned_count)
elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab,
true, NULL);
if (count)
{
elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab,
false, NULL);
/* Sort relative relocations by addresses. We only need to
sort them in the first pass since the relative positions
won't change. */
if (htab->generate_relative_reloc_pass == 0)
qsort (htab->relative_reloc.data, count,
sizeof (struct elf_x86_relative_reloc_record),
elf_x86_relative_reloc_compare);
elf_x86_compute_dl_relr_bitmap (info, htab, need_layout);
}
htab->generate_relative_reloc_pass++;
return true;
}
bool
_bfd_elf_x86_finish_relative_relocs (struct bfd_link_info *info)
{
struct elf_x86_link_hash_table *htab;
const struct elf_backend_data *bed;
Elf_Internal_Rela outrel;
bool is_x86_64;
bfd_size_type count;
/* Do nothing for ld -r. */
if (bfd_link_relocatable (info))
return true;
bed = get_elf_backend_data (info->output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return false;
is_x86_64 = bed->target_id == X86_64_ELF_DATA;
outrel.r_info = htab->r_info (0, htab->relative_r_type);
if (htab->unaligned_relative_reloc.count)
elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab,
true, &outrel);
count = htab->relative_reloc.count;
if (count)
{
elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab,
false, &outrel);
elf_x86_compute_dl_relr_bitmap (info, htab, NULL);
elf_x86_write_dl_relr_bitmap (info, htab);
}
return true;
}
bool
_bfd_elf_x86_valid_reloc_p (asection *input_section,
struct bfd_link_info *info,
struct elf_x86_link_hash_table *htab,
const Elf_Internal_Rela *rel,
struct elf_link_hash_entry *h,
Elf_Internal_Sym *sym,
Elf_Internal_Shdr *symtab_hdr,
bool *no_dynreloc_p)
{
bool valid_p = true;
*no_dynreloc_p = false;
/* Check If relocation against non-preemptible absolute symbol is
valid in PIC. FIXME: Can't use SYMBOL_REFERENCES_LOCAL_P since
it may call _bfd_elf_link_hide_sym_by_version and result in
ld-elfvers/ vers21 test failure. */
if (bfd_link_pic (info)
&& (h == NULL || SYMBOL_REFERENCES_LOCAL (info, h)))
{
const struct elf_backend_data *bed;
unsigned int r_type;
Elf_Internal_Rela irel;
/* Skip non-absolute symbol. */
if (h)
{
if (!ABS_SYMBOL_P (h))
return valid_p;
}
else if (sym->st_shndx != SHN_ABS)
return valid_p;
bed = get_elf_backend_data (input_section->owner);
r_type = ELF32_R_TYPE (rel->r_info);
irel = *rel;
/* Only allow relocations against absolute symbol, which can be
resolved as absolute value + addend. GOTPCREL and GOT32
relocations are allowed since absolute value + addend is
stored in the GOT slot. */
if (bed->target_id == X86_64_ELF_DATA)
{
r_type &= ~R_X86_64_converted_reloc_bit;
valid_p = (r_type == R_X86_64_64
|| r_type == R_X86_64_32
|| r_type == R_X86_64_32S
|| r_type == R_X86_64_16
|| r_type == R_X86_64_8
|| r_type == R_X86_64_GOTPCREL
|| r_type == R_X86_64_GOTPCRELX
|| r_type == R_X86_64_REX_GOTPCRELX);
if (!valid_p)
{
unsigned int r_symndx = htab->r_sym (rel->r_info);
irel.r_info = htab->r_info (r_symndx, r_type);
}
}
else
valid_p = (r_type == R_386_32
|| r_type == R_386_16
|| r_type == R_386_8
|| r_type == R_386_GOT32
|| r_type == R_386_GOT32X);
if (valid_p)
*no_dynreloc_p = true;
else
{
const char *name;
arelent internal_reloc;
if (!bed->elf_info_to_howto (input_section->owner,
&internal_reloc, &irel)
|| internal_reloc.howto == NULL)
abort ();
if (h)
name = h->root.root.string;
else
name = bfd_elf_sym_name (input_section->owner, symtab_hdr,
sym, NULL);
info->callbacks->einfo
/* xgettext:c-format */
(_("%F%P: %pB: relocation %s against absolute symbol "
"`%s' in section `%pA' is disallowed\n"),
input_section->owner, internal_reloc.howto->name, name,
input_section);
bfd_set_error (bfd_error_bad_value);
}
}
return valid_p;
}
/* Set the sizes of the dynamic sections. */
bool
_bfd_x86_elf_late_size_sections (bfd *output_bfd,
struct bfd_link_info *info)
{
struct elf_x86_link_hash_table *htab;
bfd *dynobj;
asection *s;
bool relocs;
bfd *ibfd;
const struct elf_backend_data *bed
= get_elf_backend_data (output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return false;
dynobj = htab->elf.dynobj;
if (dynobj == NULL)
return true;
/* Set up .got offsets for local syms, and space for local dynamic
relocs. */
for (ibfd = info->input_bfds; ibfd != NULL; ibfd = ibfd->link.next)
{
bfd_signed_vma *local_got;
bfd_signed_vma *end_local_got;
char *local_tls_type;
bfd_vma *local_tlsdesc_gotent;
bfd_size_type locsymcount;
Elf_Internal_Shdr *symtab_hdr;
asection *srel;
if (! is_x86_elf (ibfd, htab))
continue;
for (s = ibfd->sections; s != NULL; s = s->next)
{
struct elf_dyn_relocs *p;
for (p = ((struct elf_dyn_relocs *)
elf_section_data (s)->local_dynrel);
p != NULL;
p = p->next)
{
if (!bfd_is_abs_section (p->sec)
&& bfd_is_abs_section (p->sec->output_section))
{
/* Input section has been discarded, either because
it is a copy of a linkonce section or due to
linker script /DISCARD/, so we'll be discarding
the relocs too. */
}
else if (htab->elf.target_os == is_vxworks
&& strcmp (p->sec->output_section->name,
".tls_vars") == 0)
{
/* Relocations in vxworks .tls_vars sections are
handled specially by the loader. */
}
else if (p->count != 0)
{
srel = elf_section_data (p->sec)->sreloc;
srel->size += p->count * htab->sizeof_reloc;
if ((p->sec->output_section->flags & SEC_READONLY) != 0
&& (info->flags & DF_TEXTREL) == 0)
{
info->flags |= DF_TEXTREL;
if (bfd_link_textrel_check (info))
/* xgettext:c-format */
info->callbacks->einfo
(_("%P: %pB: warning: relocation "
"in read-only section `%pA'\n"),
p->sec->owner, p->sec);
}
}
}
}
local_got = elf_local_got_refcounts (ibfd);
if (!local_got)
continue;
symtab_hdr = &elf_symtab_hdr (ibfd);
locsymcount = symtab_hdr->sh_info;
end_local_got = local_got + locsymcount;
local_tls_type = elf_x86_local_got_tls_type (ibfd);
local_tlsdesc_gotent = elf_x86_local_tlsdesc_gotent (ibfd);
s = htab->elf.sgot;
srel = htab->elf.srelgot;
for (; local_got < end_local_got;
++local_got, ++local_tls_type, ++local_tlsdesc_gotent)
{
*local_tlsdesc_gotent = (bfd_vma) -1;
if (*local_got > 0)
{
if (GOT_TLS_GDESC_P (*local_tls_type))
{
*local_tlsdesc_gotent = htab->elf.sgotplt->size
- elf_x86_compute_jump_table_size (htab);
htab->elf.sgotplt->size += 2 * htab->got_entry_size;
*local_got = (bfd_vma) -2;
}
if (! GOT_TLS_GDESC_P (*local_tls_type)
|| GOT_TLS_GD_P (*local_tls_type))
{
*local_got = s->size;
s->size += htab->got_entry_size;
if (GOT_TLS_GD_P (*local_tls_type)
|| *local_tls_type == GOT_TLS_IE_BOTH)
s->size += htab->got_entry_size;
}
if ((bfd_link_pic (info) && *local_tls_type != GOT_ABS)
|| GOT_TLS_GD_ANY_P (*local_tls_type)
|| (*local_tls_type & GOT_TLS_IE))
{
if (*local_tls_type == GOT_TLS_IE_BOTH)
srel->size += 2 * htab->sizeof_reloc;
else if (GOT_TLS_GD_P (*local_tls_type)
|| ! GOT_TLS_GDESC_P (*local_tls_type))
srel->size += htab->sizeof_reloc;
if (GOT_TLS_GDESC_P (*local_tls_type))
{
htab->elf.srelplt->size += htab->sizeof_reloc;
if (bed->target_id == X86_64_ELF_DATA)
htab->elf.tlsdesc_plt = (bfd_vma) -1;
}
}
}
else
*local_got = (bfd_vma) -1;
}
}
if (htab->tls_ld_or_ldm_got.refcount > 0)
{
/* Allocate 2 got entries and 1 dynamic reloc for R_386_TLS_LDM
or R_X86_64_TLSLD relocs. */
htab->tls_ld_or_ldm_got.offset = htab->elf.sgot->size;
htab->elf.sgot->size += 2 * htab->got_entry_size;
htab->elf.srelgot->size += htab->sizeof_reloc;
}
else
htab->tls_ld_or_ldm_got.offset = -1;
/* Allocate global sym .plt and .got entries, and space for global
sym dynamic relocs. */
elf_link_hash_traverse (&htab->elf, elf_x86_allocate_dynrelocs,
info);
/* Allocate .plt and .got entries, and space for local symbols. */
htab_traverse (htab->loc_hash_table, elf_x86_allocate_local_dynreloc,
info);
/* For every jump slot reserved in the sgotplt, reloc_count is
incremented. However, when we reserve space for TLS descriptors,
it's not incremented, so in order to compute the space reserved
for them, it suffices to multiply the reloc count by the jump
slot size.
PR ld/13302: We start next_irelative_index at the end of .rela.plt
so that R_{386,X86_64}_IRELATIVE entries come last. */
if (htab->elf.srelplt)
{
htab->next_tls_desc_index = htab->elf.srelplt->reloc_count;
htab->sgotplt_jump_table_size
= elf_x86_compute_jump_table_size (htab);
htab->next_irelative_index = htab->elf.srelplt->reloc_count - 1;
}
else if (htab->elf.irelplt)
htab->next_irelative_index = htab->elf.irelplt->reloc_count - 1;
if (htab->elf.tlsdesc_plt)
{
/* NB: tlsdesc_plt is set only for x86-64. If we're not using
lazy TLS relocations, don't generate the PLT and GOT entries
they require. */
if ((info->flags & DF_BIND_NOW))
htab->elf.tlsdesc_plt = 0;
else
{
htab->elf.tlsdesc_got = htab->elf.sgot->size;
htab->elf.sgot->size += htab->got_entry_size;
/* Reserve room for the initial entry.
FIXME: we could probably do away with it in this case. */
if (htab->elf.splt->size == 0)
htab->elf.splt->size = htab->plt.plt_entry_size;
htab->elf.tlsdesc_plt = htab->elf.splt->size;
htab->elf.splt->size += htab->plt.plt_entry_size;
}
}
if (htab->elf.sgotplt)
{
/* Don't allocate .got.plt section if there are no GOT nor PLT
entries and there is no reference to _GLOBAL_OFFSET_TABLE_. */
if ((htab->elf.hgot == NULL
|| !htab->got_referenced)
&& (htab->elf.sgotplt->size == bed->got_header_size)
&& (htab->elf.splt == NULL
|| htab->elf.splt->size == 0)
&& (htab->elf.sgot == NULL
|| htab->elf.sgot->size == 0)
&& (htab->elf.iplt == NULL
|| htab->elf.iplt->size == 0)
&& (htab->elf.igotplt == NULL
|| htab->elf.igotplt->size == 0))
{
htab->elf.sgotplt->size = 0;
/* Solaris requires to keep _GLOBAL_OFFSET_TABLE_ even if it
isn't used. */
if (htab->elf.hgot != NULL
&& htab->elf.target_os != is_solaris)
{
/* Remove the unused _GLOBAL_OFFSET_TABLE_ from symbol
table. */
htab->elf.hgot->root.type = bfd_link_hash_undefined;
htab->elf.hgot->root.u.undef.abfd
= htab->elf.hgot->root.u.def.section->owner;
htab->elf.hgot->root.linker_def = 0;
htab->elf.hgot->ref_regular = 0;
htab->elf.hgot->def_regular = 0;
}
}
}
if (_bfd_elf_eh_frame_present (info))
{
if (htab->plt_eh_frame != NULL
&& htab->elf.splt != NULL
&& htab->elf.splt->size != 0
&& !bfd_is_abs_section (htab->elf.splt->output_section))
htab->plt_eh_frame->size = htab->plt.eh_frame_plt_size;
if (htab->plt_got_eh_frame != NULL
&& htab->plt_got != NULL
&& htab->plt_got->size != 0
&& !bfd_is_abs_section (htab->plt_got->output_section))
htab->plt_got_eh_frame->size
= htab->non_lazy_plt->eh_frame_plt_size;
/* Unwind info for the second PLT and .plt.got sections are
identical. */
if (htab->plt_second_eh_frame != NULL
&& htab->plt_second != NULL
&& htab->plt_second->size != 0
&& !bfd_is_abs_section (htab->plt_second->output_section))
htab->plt_second_eh_frame->size
= htab->non_lazy_plt->eh_frame_plt_size;
}
/* No need to size the .sframe section explicitly because the write-out
mechanism is different. Simply prep up the FDE/FRE for the
.plt section. */
if (_bfd_elf_sframe_present (info))
{
if (htab->plt_sframe != NULL
&& htab->elf.splt != NULL
&& htab->elf.splt->size != 0
&& !bfd_is_abs_section (htab->elf.splt->output_section))
{
_bfd_x86_elf_create_sframe_plt (output_bfd, info, SFRAME_PLT);
/* FIXME - Dirty Hack. Set the size to something non-zero for now,
so that the section does not get stripped out below. The precise
size of this section is known only when the contents are
serialized in _bfd_x86_elf_write_sframe_plt. */
htab->plt_sframe->size = sizeof (sframe_header) + 1;
}
/* FIXME - generate for .plt.got ? */
if (htab->plt_second_sframe != NULL
&& htab->plt_second != NULL
&& htab->plt_second->size != 0
&& !bfd_is_abs_section (htab->plt_second->output_section))
{
/* SFrame stack trace info for the second PLT. */
_bfd_x86_elf_create_sframe_plt (output_bfd, info, SFRAME_PLT_SEC);
/* FIXME - Dirty Hack. Set the size to something non-zero for now,
so that the section does not get stripped out below. The precise
size of this section is known only when the contents are
serialized in _bfd_x86_elf_write_sframe_plt. */
htab->plt_second_sframe->size = sizeof (sframe_header) + 1;
}
}
asection *resolved_plt = NULL;
if (htab->params->mark_plt && htab->elf.dynamic_sections_created)
{
if (htab->plt_second != NULL)
resolved_plt = htab->plt_second;
else
resolved_plt = htab->elf.splt;
if (resolved_plt != NULL && resolved_plt->size == 0)
resolved_plt = NULL;
}
/* We now have determined the sizes of the various dynamic sections.
Allocate memory for them. */
relocs = false;
for (s = dynobj->sections; s != NULL; s = s->next)
{
bool strip_section = true;
if ((s->flags & SEC_LINKER_CREATED) == 0)
continue;
/* The .relr.dyn section for compact relative relocation will
be filled later. */
if (s == htab->elf.srelrdyn)
continue;
if (s == htab->elf.splt
|| s == htab->elf.sgot)
{
/* Strip this section if we don't need it; see the
comment below. */
/* We'd like to strip these sections if they aren't needed, but if
we've exported dynamic symbols from them we must leave them.
It's too late to tell BFD to get rid of the symbols. */
if (htab->elf.hplt != NULL)
strip_section = false;
}
else if (s == htab->elf.sgotplt
|| s == htab->elf.iplt
|| s == htab->elf.igotplt
|| s == htab->plt_second
|| s == htab->plt_got
|| s == htab->plt_eh_frame
|| s == htab->plt_got_eh_frame
|| s == htab->plt_second_eh_frame
|| s == htab->plt_sframe
|| s == htab->plt_second_sframe
|| s == htab->elf.sdynbss
|| s == htab->elf.sdynrelro)
{
/* Strip these too. */
}
else if (htab->is_reloc_section (bfd_section_name (s)))
{
if (s->size != 0
&& s != htab->elf.srelplt
&& s != htab->srelplt2)
relocs = true;
/* We use the reloc_count field as a counter if we need
to copy relocs into the output file. */
if (s != htab->elf.srelplt)
s->reloc_count = 0;
}
else
{
/* It's not one of our sections, so don't allocate space. */
continue;
}
if (s->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. */
if (strip_section)
s->flags |= SEC_EXCLUDE;
continue;
}
if ((s->flags & SEC_HAS_CONTENTS) == 0)
continue;
/* Skip allocating contents for .sframe section as it is written
out differently. See below. */
if ((s == htab->plt_sframe) || (s == htab->plt_second_sframe))
continue;
/* NB: Initially, the iplt section has minimal alignment to
avoid moving dot of the following section backwards when
it is empty. Update its section alignment now since it
is non-empty. */
if (s == htab->elf.iplt)
bfd_set_section_alignment (s, htab->plt.iplt_alignment);
/* Allocate memory for the section contents. We use bfd_zalloc
here in case unused entries are not reclaimed before the
section's contents are written out. This should not happen,
but this way if it does, we get a R_386_NONE or R_X86_64_NONE
reloc instead of garbage. */
s->contents = (unsigned char *) bfd_zalloc (dynobj, s->size);
if (s->contents == NULL)
return false;
}
if (htab->plt_eh_frame != NULL
&& htab->plt_eh_frame->contents != NULL)
{
memcpy (htab->plt_eh_frame->contents,
htab->plt.eh_frame_plt,
htab->plt_eh_frame->size);
bfd_put_32 (dynobj, htab->elf.splt->size,
htab->plt_eh_frame->contents + PLT_FDE_LEN_OFFSET);
}
if (htab->plt_got_eh_frame != NULL
&& htab->plt_got_eh_frame->contents != NULL)
{
memcpy (htab->plt_got_eh_frame->contents,
htab->non_lazy_plt->eh_frame_plt,
htab->plt_got_eh_frame->size);
bfd_put_32 (dynobj, htab->plt_got->size,
(htab->plt_got_eh_frame->contents
+ PLT_FDE_LEN_OFFSET));
}
if (htab->plt_second_eh_frame != NULL
&& htab->plt_second_eh_frame->contents != NULL)
{
memcpy (htab->plt_second_eh_frame->contents,
htab->non_lazy_plt->eh_frame_plt,
htab->plt_second_eh_frame->size);
bfd_put_32 (dynobj, htab->plt_second->size,
(htab->plt_second_eh_frame->contents
+ PLT_FDE_LEN_OFFSET));
}
if (_bfd_elf_sframe_present (info))
{
if (htab->plt_sframe != NULL
&& htab->elf.splt != NULL
&& htab->elf.splt->size != 0
&& htab->plt_sframe->contents == NULL)
_bfd_x86_elf_write_sframe_plt (output_bfd, info, SFRAME_PLT);
if (htab->plt_second_sframe != NULL
&& htab->elf.splt != NULL
&& htab->elf.splt->size != 0
&& htab->plt_second_sframe->contents == NULL)
_bfd_x86_elf_write_sframe_plt (output_bfd, info, SFRAME_PLT_SEC);
}
if (resolved_plt != NULL
&& (!_bfd_elf_add_dynamic_entry (info, DT_X86_64_PLT, 0)
|| !_bfd_elf_add_dynamic_entry (info, DT_X86_64_PLTSZ, 0)
|| !_bfd_elf_add_dynamic_entry (info, DT_X86_64_PLTENT, 0)))
return false;
return _bfd_elf_maybe_vxworks_add_dynamic_tags (output_bfd, info,
relocs);
}
/* Finish up the x86 dynamic sections. */
struct elf_x86_link_hash_table *
_bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd,
struct bfd_link_info *info)
{
struct elf_x86_link_hash_table *htab;
const struct elf_backend_data *bed;
bfd *dynobj;
asection *sdyn;
bfd_byte *dyncon, *dynconend;
bfd_size_type sizeof_dyn;
bed = get_elf_backend_data (output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return htab;
dynobj = htab->elf.dynobj;
sdyn = htab->elf.dynamic;
/* GOT is always created in setup_gnu_properties. But it may not be
needed. .got.plt section may be needed for static IFUNC. */
if (htab->elf.sgotplt && htab->elf.sgotplt->size > 0)
{
bfd_vma dynamic_addr;
if (bfd_is_abs_section (htab->elf.sgotplt->output_section))
{
_bfd_error_handler
(_("discarded output section: `%pA'"), htab->elf.sgotplt);
return NULL;
}
elf_section_data (htab->elf.sgotplt->output_section)->this_hdr.sh_entsize
= htab->got_entry_size;
dynamic_addr = (sdyn == NULL
? (bfd_vma) 0
: sdyn->output_section->vma + sdyn->output_offset);
/* Set the first entry in the global offset table to the address
of the dynamic section. Write GOT[1] and GOT[2], needed for
the dynamic linker. */
if (htab->got_entry_size == 8)
{
bfd_put_64 (output_bfd, dynamic_addr,
htab->elf.sgotplt->contents);
bfd_put_64 (output_bfd, (bfd_vma) 0,
htab->elf.sgotplt->contents + 8);
bfd_put_64 (output_bfd, (bfd_vma) 0,
htab->elf.sgotplt->contents + 8*2);
}
else
{
bfd_put_32 (output_bfd, dynamic_addr,
htab->elf.sgotplt->contents);
bfd_put_32 (output_bfd, 0,
htab->elf.sgotplt->contents + 4);
bfd_put_32 (output_bfd, 0,
htab->elf.sgotplt->contents + 4*2);
}
}
if (!htab->elf.dynamic_sections_created)
return htab;
if (sdyn == NULL || htab->elf.sgot == NULL)
abort ();
asection *resolved_plt;
if (htab->plt_second != NULL)
resolved_plt = htab->plt_second;
else
resolved_plt = htab->elf.splt;
sizeof_dyn = bed->s->sizeof_dyn;
dyncon = sdyn->contents;
dynconend = sdyn->contents + sdyn->size;
for (; dyncon < dynconend; dyncon += sizeof_dyn)
{
Elf_Internal_Dyn dyn;
asection *s;
(*bed->s->swap_dyn_in) (dynobj, dyncon, &dyn);
switch (dyn.d_tag)
{
default:
if (htab->elf.target_os == is_vxworks
&& elf_vxworks_finish_dynamic_entry (output_bfd, &dyn))
break;
continue;
case DT_PLTGOT:
s = htab->elf.sgotplt;
dyn.d_un.d_ptr = s->output_section->vma + s->output_offset;
break;
case DT_JMPREL:
s = htab->elf.srelplt;
dyn.d_un.d_ptr = s->output_section->vma + s->output_offset;
break;
case DT_PLTRELSZ:
s = htab->elf.srelplt;
dyn.d_un.d_val = s->size;
break;
case DT_TLSDESC_PLT:
s = htab->elf.splt;
dyn.d_un.d_ptr = s->output_section->vma + s->output_offset
+ htab->elf.tlsdesc_plt;
break;
case DT_TLSDESC_GOT:
s = htab->elf.sgot;
dyn.d_un.d_ptr = s->output_section->vma + s->output_offset
+ htab->elf.tlsdesc_got;
break;
case DT_X86_64_PLT:
s = resolved_plt->output_section;
dyn.d_un.d_ptr = s->output_section->vma + s->output_offset;
break;
case DT_X86_64_PLTSZ:
dyn.d_un.d_val = resolved_plt->size;
break;
case DT_X86_64_PLTENT:
dyn.d_un.d_ptr = htab->plt.plt_entry_size;
break;
}
(*bed->s->swap_dyn_out) (output_bfd, &dyn, dyncon);
}
if (htab->plt_got != NULL && htab->plt_got->size > 0)
elf_section_data (htab->plt_got->output_section)
->this_hdr.sh_entsize = htab->non_lazy_plt->plt_entry_size;
if (htab->plt_second != NULL && htab->plt_second->size > 0)
elf_section_data (htab->plt_second->output_section)
->this_hdr.sh_entsize = htab->non_lazy_plt->plt_entry_size;
/* Adjust .eh_frame for .plt section. */
if (htab->plt_eh_frame != NULL
&& htab->plt_eh_frame->contents != NULL)
{
if (htab->elf.splt != NULL
&& htab->elf.splt->size != 0
&& (htab->elf.splt->flags & SEC_EXCLUDE) == 0
&& htab->elf.splt->output_section != NULL
&& htab->plt_eh_frame->output_section != NULL)
{
bfd_vma plt_start = htab->elf.splt->output_section->vma;
bfd_vma eh_frame_start = htab->plt_eh_frame->output_section->vma
+ htab->plt_eh_frame->output_offset
+ PLT_FDE_START_OFFSET;
bfd_put_signed_32 (dynobj, plt_start - eh_frame_start,
htab->plt_eh_frame->contents
+ PLT_FDE_START_OFFSET);
}
if (htab->plt_eh_frame->sec_info_type == SEC_INFO_TYPE_EH_FRAME)
{
if (! _bfd_elf_write_section_eh_frame (output_bfd, info,
htab->plt_eh_frame,
htab->plt_eh_frame->contents))
return NULL;
}
}
/* Adjust .eh_frame for .plt.got section. */
if (htab->plt_got_eh_frame != NULL
&& htab->plt_got_eh_frame->contents != NULL)
{
if (htab->plt_got != NULL
&& htab->plt_got->size != 0
&& (htab->plt_got->flags & SEC_EXCLUDE) == 0
&& htab->plt_got->output_section != NULL
&& htab->plt_got_eh_frame->output_section != NULL)
{
bfd_vma plt_start = htab->plt_got->output_section->vma;
bfd_vma eh_frame_start = htab->plt_got_eh_frame->output_section->vma
+ htab->plt_got_eh_frame->output_offset
+ PLT_FDE_START_OFFSET;
bfd_put_signed_32 (dynobj, plt_start - eh_frame_start,
htab->plt_got_eh_frame->contents
+ PLT_FDE_START_OFFSET);
}
if (htab->plt_got_eh_frame->sec_info_type == SEC_INFO_TYPE_EH_FRAME)
{
if (! _bfd_elf_write_section_eh_frame (output_bfd, info,
htab->plt_got_eh_frame,
htab->plt_got_eh_frame->contents))
return NULL;
}
}
/* Adjust .eh_frame for the second PLT section. */
if (htab->plt_second_eh_frame != NULL
&& htab->plt_second_eh_frame->contents != NULL)
{
if (htab->plt_second != NULL
&& htab->plt_second->size != 0
&& (htab->plt_second->flags & SEC_EXCLUDE) == 0
&& htab->plt_second->output_section != NULL
&& htab->plt_second_eh_frame->output_section != NULL)
{
bfd_vma plt_start = htab->plt_second->output_section->vma;
bfd_vma eh_frame_start
= (htab->plt_second_eh_frame->output_section->vma
+ htab->plt_second_eh_frame->output_offset
+ PLT_FDE_START_OFFSET);
bfd_put_signed_32 (dynobj, plt_start - eh_frame_start,
htab->plt_second_eh_frame->contents
+ PLT_FDE_START_OFFSET);
}
if (htab->plt_second_eh_frame->sec_info_type
== SEC_INFO_TYPE_EH_FRAME)
{
if (! _bfd_elf_write_section_eh_frame (output_bfd, info,
htab->plt_second_eh_frame,
htab->plt_second_eh_frame->contents))
return NULL;
}
}
/* Make any adjustment if necessary and merge .sframe section to
create the final .sframe section for output_bfd. */
if (htab->plt_sframe != NULL
&& htab->plt_sframe->contents != NULL)
{
if (htab->elf.splt != NULL
&& htab->elf.splt->size != 0
&& (htab->elf.splt->flags & SEC_EXCLUDE) == 0
&& htab->elf.splt->output_section != NULL
&& htab->plt_sframe->output_section != NULL)
{
bfd_vma plt_start = htab->elf.splt->output_section->vma;
bfd_vma sframe_start = htab->plt_sframe->output_section->vma
+ htab->plt_sframe->output_offset
+ PLT_SFRAME_FDE_START_OFFSET;
#if 0 /* FIXME Testing only. Remove before review. */
bfd_vma test_value = (plt_start - sframe_start)
+ htab->plt_sframe->output_section->vma
+ htab->plt_sframe->output_offset
+ PLT_SFRAME_FDE_START_OFFSET;
bfd_put_signed_32 (dynobj, test_value,
#endif
bfd_put_signed_32 (dynobj, plt_start - sframe_start,
htab->plt_sframe->contents
+ PLT_SFRAME_FDE_START_OFFSET);
}
if (htab->plt_sframe->sec_info_type == SEC_INFO_TYPE_SFRAME)
{
if (! _bfd_elf_merge_section_sframe (output_bfd, info,
htab->plt_sframe,
htab->plt_sframe->contents))
return NULL;
}
}
if (htab->plt_second_sframe != NULL
&& htab->plt_second_sframe->contents != NULL)
{
if (htab->plt_second != NULL
&& htab->plt_second->size != 0
&& (htab->plt_second->flags & SEC_EXCLUDE) == 0
&& htab->plt_second->output_section != NULL
&& htab->plt_second_sframe->output_section != NULL)
{
bfd_vma plt_start = htab->plt_second->output_section->vma;
bfd_vma sframe_start
= (htab->plt_second_sframe->output_section->vma
+ htab->plt_second_sframe->output_offset
+ PLT_SFRAME_FDE_START_OFFSET);
#if 0 /* FIXME Testing only. Remove before review. */
bfd_vma test_value = (plt_start - sframe_start)
+ htab->plt_second_sframe->output_section->vma
+ htab->plt_second_sframe->output_offset
+ PLT_SFRAME_FDE_START_OFFSET;
bfd_put_signed_32 (dynobj, test_value,
#endif
bfd_put_signed_32 (dynobj, plt_start - sframe_start,
htab->plt_second_sframe->contents
+ PLT_SFRAME_FDE_START_OFFSET);
}
if (htab->plt_second_sframe->sec_info_type == SEC_INFO_TYPE_SFRAME)
{
if (! _bfd_elf_merge_section_sframe (output_bfd, info,
htab->plt_second_sframe,
htab->plt_second_sframe->contents))
return NULL;
}
}
if (htab->elf.sgot && htab->elf.sgot->size > 0)
elf_section_data (htab->elf.sgot->output_section)->this_hdr.sh_entsize
= htab->got_entry_size;
return htab;
}
bool
_bfd_x86_elf_early_size_sections (bfd *output_bfd,
struct bfd_link_info *info)
{
asection *tls_sec = elf_hash_table (info)->tls_sec;
if (tls_sec && !bfd_link_relocatable (info))
{
struct elf_link_hash_entry *tlsbase;
tlsbase = elf_link_hash_lookup (elf_hash_table (info),
"_TLS_MODULE_BASE_",
false, false, false);
if (tlsbase && tlsbase->type == STT_TLS)
{
struct elf_x86_link_hash_table *htab;
struct bfd_link_hash_entry *bh = NULL;
const struct elf_backend_data *bed
= get_elf_backend_data (output_bfd);
htab = elf_x86_hash_table (info, bed->target_id);
if (htab == NULL)
return false;
if (!(_bfd_generic_link_add_one_symbol