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gnu / binutils-gdb / 511c6575b2febee533a4d8796647bbabc2c27249 / . / bfd / elflink.c
blob: 9eb1122d5133259254c0d8899e1452558bd4e128 [file] [log] [blame]
/* ELF linking support for BFD.
Copyright (C) 1995-2024 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 "sysdep.h"
#include "bfd.h"
#include "bfdlink.h"
#include "libbfd.h"
#define ARCH_SIZE 0
#include "elf-bfd.h"
#include "safe-ctype.h"
#include "libiberty.h"
#include "objalloc.h"
#if BFD_SUPPORTS_PLUGINS
#include "plugin-api.h"
#include "plugin.h"
#endif
#include <limits.h>
#ifndef CHAR_BIT
#define CHAR_BIT 8
#endif
/* This struct is used to pass information to routines called via
elf_link_hash_traverse which must return failure. */
struct elf_info_failed
{
struct bfd_link_info *info;
bool failed;
};
static bool _bfd_elf_fix_symbol_flags
(struct elf_link_hash_entry *, struct elf_info_failed *);
/* Return false if linker should avoid caching relocation information
and symbol tables of input files in memory. */
static bool
_bfd_elf_link_keep_memory (struct bfd_link_info *info)
{
#ifdef USE_MMAP
/* Don't cache symbol nor relocation tables if they are mapped in.
NB: Since the --no-keep-memory linker option causes:
https://sourceware.org/bugzilla/show_bug.cgi?id=31458
this is opt-in by each backend. */
const struct elf_backend_data *bed
= get_elf_backend_data (info->output_bfd);
if (bed != NULL && bed->use_mmap)
return false;
#endif
bfd *abfd;
bfd_size_type size;
if (!info->keep_memory)
return false;
if (info->max_cache_size == (bfd_size_type) -1)
return true;
abfd = info->input_bfds;
size = info->cache_size;
do
{
if (size >= info->max_cache_size)
{
/* Over the limit. Reduce the memory usage. */
info->keep_memory = false;
return false;
}
if (!abfd)
break;
size += abfd->alloc_size;
abfd = abfd->link.next;
}
while (1);
return true;
}
asection *
_bfd_elf_section_for_symbol (struct elf_reloc_cookie *cookie,
unsigned long r_symndx,
bool discard)
{
if (r_symndx >= cookie->locsymcount
|| ELF_ST_BIND (cookie->locsyms[r_symndx].st_info) != STB_LOCAL)
{
struct elf_link_hash_entry *h;
h = cookie->sym_hashes[r_symndx - cookie->extsymoff];
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)
&& discarded_section (h->root.u.def.section))
return h->root.u.def.section;
else
return NULL;
}
else
{
/* It's not a relocation against a global symbol,
but it could be a relocation against a local
symbol for a discarded section. */
asection *isec;
Elf_Internal_Sym *isym;
/* Need to: get the symbol; get the section. */
isym = &cookie->locsyms[r_symndx];
isec = bfd_section_from_elf_index (cookie->abfd, isym->st_shndx);
if (isec != NULL
&& discard ? discarded_section (isec) : 1)
return isec;
}
return NULL;
}
/* Define a symbol in a dynamic linkage section. */
struct elf_link_hash_entry *
_bfd_elf_define_linkage_sym (bfd *abfd,
struct bfd_link_info *info,
asection *sec,
const char *name)
{
struct elf_link_hash_entry *h;
struct bfd_link_hash_entry *bh;
const struct elf_backend_data *bed;
h = elf_link_hash_lookup (elf_hash_table (info), name, false, false, false);
if (h != NULL)
{
/* Zap symbol defined in an as-needed lib that wasn't linked.
This is a symptom of a larger problem: Absolute symbols
defined in shared libraries can't be overridden, because we
lose the link to the bfd which is via the symbol section. */
h->root.type = bfd_link_hash_new;
bh = &h->root;
}
else
bh = NULL;
bed = get_elf_backend_data (abfd);
if (!_bfd_generic_link_add_one_symbol (info, abfd, name, BSF_GLOBAL,
sec, 0, NULL, false, bed->collect,
&bh))
return NULL;
h = (struct elf_link_hash_entry *) bh;
BFD_ASSERT (h != NULL);
h->def_regular = 1;
h->non_elf = 0;
h->root.linker_def = 1;
h->type = STT_OBJECT;
if (ELF_ST_VISIBILITY (h->other) != STV_INTERNAL)
h->other = (h->other & ~ELF_ST_VISIBILITY (-1)) | STV_HIDDEN;
(*bed->elf_backend_hide_symbol) (info, h, true);
return h;
}
bool
_bfd_elf_create_got_section (bfd *abfd, struct bfd_link_info *info)
{
flagword flags;
asection *s;
struct elf_link_hash_entry *h;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
struct elf_link_hash_table *htab = elf_hash_table (info);
/* This function may be called more than once. */
if (htab->sgot != NULL)
return true;
flags = bed->dynamic_sec_flags;
s = bfd_make_section_anyway_with_flags (abfd,
(bed->rela_plts_and_copies_p
? ".rela.got" : ".rel.got"),
(bed->dynamic_sec_flags
| SEC_READONLY));
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
htab->srelgot = s;
s = bfd_make_section_anyway_with_flags (abfd, ".got", flags);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
htab->sgot = s;
if (bed->want_got_plt)
{
s = bfd_make_section_anyway_with_flags (abfd, ".got.plt", flags);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
htab->sgotplt = s;
}
/* The first bit of the global offset table is the header. */
s->size += bed->got_header_size;
if (bed->want_got_sym)
{
/* Define the symbol _GLOBAL_OFFSET_TABLE_ at the start of the .got
(or .got.plt) section. We don't do this in the linker script
because we don't want to define the symbol if we are not creating
a global offset table. */
h = _bfd_elf_define_linkage_sym (abfd, info, s,
"_GLOBAL_OFFSET_TABLE_");
elf_hash_table (info)->hgot = h;
if (h == NULL)
return false;
}
return true;
}
/* Create a strtab to hold the dynamic symbol names. */
static bool
_bfd_elf_link_create_dynstrtab (bfd *abfd, struct bfd_link_info *info)
{
struct elf_link_hash_table *hash_table;
hash_table = elf_hash_table (info);
if (hash_table->dynobj == NULL)
{
/* We may not set dynobj, an input file holding linker created
dynamic sections to abfd, which may be a dynamic object with
its own dynamic sections. We need to find a normal input file
to hold linker created sections if possible. */
if ((abfd->flags & (DYNAMIC | BFD_PLUGIN)) != 0)
{
bfd *ibfd;
asection *s;
for (ibfd = info->input_bfds; ibfd; ibfd = ibfd->link.next)
if ((ibfd->flags
& (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0
&& bfd_get_flavour (ibfd) == bfd_target_elf_flavour
&& elf_object_id (ibfd) == elf_hash_table_id (hash_table)
&& !((s = ibfd->sections) != NULL
&& s->sec_info_type == SEC_INFO_TYPE_JUST_SYMS))
{
abfd = ibfd;
break;
}
}
hash_table->dynobj = abfd;
}
if (hash_table->dynstr == NULL)
{
hash_table->dynstr = _bfd_elf_strtab_init ();
if (hash_table->dynstr == NULL)
return false;
}
return true;
}
/* Create some sections which will be filled in with dynamic linking
information. ABFD is an input file which requires dynamic sections
to be created. The dynamic sections take up virtual memory space
when the final executable is run, so we need to create them before
addresses are assigned to the output sections. We work out the
actual contents and size of these sections later. */
bool
_bfd_elf_link_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info)
{
flagword flags;
asection *s;
const struct elf_backend_data *bed;
struct elf_link_hash_entry *h;
if (! is_elf_hash_table (info->hash))
return false;
if (elf_hash_table (info)->dynamic_sections_created)
return true;
if (!_bfd_elf_link_create_dynstrtab (abfd, info))
return false;
abfd = elf_hash_table (info)->dynobj;
bed = get_elf_backend_data (abfd);
flags = bed->dynamic_sec_flags;
/* A dynamically linked executable has a .interp section, but a
shared library does not. */
if (bfd_link_executable (info) && !info->nointerp)
{
s = bfd_make_section_anyway_with_flags (abfd, ".interp",
flags | SEC_READONLY);
if (s == NULL)
return false;
}
/* Create sections to hold version informations. These are removed
if they are not needed. */
s = bfd_make_section_anyway_with_flags (abfd, ".gnu.version_d",
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
s = bfd_make_section_anyway_with_flags (abfd, ".gnu.version",
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, 1))
return false;
s = bfd_make_section_anyway_with_flags (abfd, ".gnu.version_r",
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
s = bfd_make_section_anyway_with_flags (abfd, ".dynsym",
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
elf_hash_table (info)->dynsym = s;
s = bfd_make_section_anyway_with_flags (abfd, ".dynstr",
flags | SEC_READONLY);
if (s == NULL)
return false;
s = bfd_make_section_anyway_with_flags (abfd, ".dynamic", flags);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
elf_hash_table (info)->dynamic = s;
/* The special symbol _DYNAMIC is always set to the start of the
.dynamic section. We could set _DYNAMIC in a linker script, but we
only want to define it if we are, in fact, creating a .dynamic
section. We don't want to define it if there is no .dynamic
section, since on some ELF platforms the start up code examines it
to decide how to initialize the process. */
h = _bfd_elf_define_linkage_sym (abfd, info, s, "_DYNAMIC");
elf_hash_table (info)->hdynamic = h;
if (h == NULL)
return false;
if (info->emit_hash)
{
s = bfd_make_section_anyway_with_flags (abfd, ".hash",
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
elf_section_data (s)->this_hdr.sh_entsize = bed->s->sizeof_hash_entry;
}
if (info->emit_gnu_hash && bed->record_xhash_symbol == NULL)
{
s = bfd_make_section_anyway_with_flags (abfd, ".gnu.hash",
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
/* For 64-bit ELF, .gnu.hash is a non-uniform entity size section:
4 32-bit words followed by variable count of 64-bit words, then
variable count of 32-bit words. */
if (bed->s->arch_size == 64)
elf_section_data (s)->this_hdr.sh_entsize = 0;
else
elf_section_data (s)->this_hdr.sh_entsize = 4;
}
if (info->enable_dt_relr)
{
s = bfd_make_section_anyway_with_flags (abfd, ".relr.dyn",
(bed->dynamic_sec_flags
| SEC_READONLY));
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
elf_hash_table (info)->srelrdyn = s;
}
/* Let the backend create the rest of the sections. This lets the
backend set the right flags. The backend will normally create
the .got and .plt sections. */
if (bed->elf_backend_create_dynamic_sections == NULL
|| ! (*bed->elf_backend_create_dynamic_sections) (abfd, info))
return false;
elf_hash_table (info)->dynamic_sections_created = true;
return true;
}
/* Create dynamic sections when linking against a dynamic object. */
bool
_bfd_elf_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info)
{
flagword flags, pltflags;
struct elf_link_hash_entry *h;
asection *s;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
struct elf_link_hash_table *htab = elf_hash_table (info);
/* We need to create .plt, .rel[a].plt, .got, .got.plt, .dynbss, and
.rel[a].bss sections. */
flags = bed->dynamic_sec_flags;
pltflags = flags;
if (bed->plt_not_loaded)
/* We do not clear SEC_ALLOC here because we still want the OS to
allocate space for the section; it's just that there's nothing
to read in from the object file. */
pltflags &= ~ (SEC_CODE | SEC_LOAD | SEC_HAS_CONTENTS);
else
pltflags |= SEC_ALLOC | SEC_CODE | SEC_LOAD;
if (bed->plt_readonly)
pltflags |= SEC_READONLY;
s = bfd_make_section_anyway_with_flags (abfd, ".plt", pltflags);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->plt_alignment))
return false;
htab->splt = s;
/* Define the symbol _PROCEDURE_LINKAGE_TABLE_ at the start of the
.plt section. */
if (bed->want_plt_sym)
{
h = _bfd_elf_define_linkage_sym (abfd, info, s,
"_PROCEDURE_LINKAGE_TABLE_");
elf_hash_table (info)->hplt = h;
if (h == NULL)
return false;
}
s = bfd_make_section_anyway_with_flags (abfd,
(bed->rela_plts_and_copies_p
? ".rela.plt" : ".rel.plt"),
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
htab->srelplt = s;
if (! _bfd_elf_create_got_section (abfd, info))
return false;
if (bed->want_dynbss)
{
/* The .dynbss section is a place to put symbols which are defined
by dynamic objects, are referenced by regular objects, and are
not functions. We must allocate space for them in the process
image and use a R_*_COPY reloc to tell the dynamic linker to
initialize them at run time. The linker script puts the .dynbss
section into the .bss section of the final image. */
s = bfd_make_section_anyway_with_flags (abfd, ".dynbss",
SEC_ALLOC | SEC_LINKER_CREATED);
if (s == NULL)
return false;
htab->sdynbss = s;
if (bed->want_dynrelro)
{
/* Similarly, but for symbols that were originally in read-only
sections. This section doesn't really need to have contents,
but make it like other .data.rel.ro sections. */
s = bfd_make_section_anyway_with_flags (abfd, ".data.rel.ro",
flags);
if (s == NULL)
return false;
htab->sdynrelro = s;
}
/* The .rel[a].bss section holds copy relocs. This section is not
normally needed. We need to create it here, though, so that the
linker will map it to an output section. We can't just create it
only if we need it, because we will not know whether we need it
until we have seen all the input files, and the first time the
main linker code calls BFD after examining all the input files
(size_dynamic_sections) the input sections have already been
mapped to the output sections. If the section turns out not to
be needed, we can discard it later. We will never need this
section when generating a shared object, since they do not use
copy relocs. */
if (bfd_link_executable (info))
{
s = bfd_make_section_anyway_with_flags (abfd,
(bed->rela_plts_and_copies_p
? ".rela.bss" : ".rel.bss"),
flags | SEC_READONLY);
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
htab->srelbss = s;
if (bed->want_dynrelro)
{
s = (bfd_make_section_anyway_with_flags
(abfd, (bed->rela_plts_and_copies_p
? ".rela.data.rel.ro" : ".rel.data.rel.ro"),
flags | SEC_READONLY));
if (s == NULL
|| !bfd_set_section_alignment (s, bed->s->log_file_align))
return false;
htab->sreldynrelro = s;
}
}
}
return true;
}
/* Record a new dynamic symbol. We record the dynamic symbols as we
read the input files, since we need to have a list of all of them
before we can determine the final sizes of the output sections.
Note that we may actually call this function even though we are not
going to output any dynamic symbols; in some cases we know that a
symbol should be in the dynamic symbol table, but only if there is
one. */
bool
bfd_elf_link_record_dynamic_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
if (h->dynindx == -1)
{
struct elf_strtab_hash *dynstr;
char *p;
const char *name;
size_t indx;
if (h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
{
/* An IR symbol should not be made dynamic. */
if (h->root.u.def.section != NULL
&& h->root.u.def.section->owner != NULL
&& (h->root.u.def.section->owner->flags & BFD_PLUGIN) != 0)
return true;
}
/* XXX: The ABI draft says the linker must turn hidden and
internal symbols into STB_LOCAL symbols when producing the
DSO. However, if ld.so honors st_other in the dynamic table,
this would not be necessary. */
switch (ELF_ST_VISIBILITY (h->other))
{
case STV_INTERNAL:
case STV_HIDDEN:
if (h->root.type != bfd_link_hash_undefined
&& h->root.type != bfd_link_hash_undefweak)
{
h->forced_local = 1;
return true;
}
default:
break;
}
h->dynindx = elf_hash_table (info)->dynsymcount;
++elf_hash_table (info)->dynsymcount;
dynstr = elf_hash_table (info)->dynstr;
if (dynstr == NULL)
{
/* Create a strtab to hold the dynamic symbol names. */
elf_hash_table (info)->dynstr = dynstr = _bfd_elf_strtab_init ();
if (dynstr == NULL)
return false;
}
char *unversioned_name = NULL;
/* We don't put any version information in the dynamic string
table. */
name = h->root.root.string;
p = strchr (name, ELF_VER_CHR);
if (p != NULL)
{
unversioned_name = bfd_malloc (p - name + 1);
memcpy (unversioned_name, name, p - name);
unversioned_name[p - name] = 0;
name = unversioned_name;
}
indx = _bfd_elf_strtab_add (dynstr, name, p != NULL);
if (p != NULL)
free (unversioned_name);
if (indx == (size_t) -1)
return false;
h->dynstr_index = indx;
}
return true;
}
/* Mark a symbol dynamic. */
static void
bfd_elf_link_mark_dynamic_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h,
Elf_Internal_Sym *sym)
{
struct bfd_elf_dynamic_list *d = info->dynamic_list;
/* It may be called more than once on the same H. */
if(h->dynamic || bfd_link_relocatable (info))
return;
if ((info->dynamic_data
&& (h->type == STT_OBJECT
|| h->type == STT_COMMON
|| (sym != NULL
&& (ELF_ST_TYPE (sym->st_info) == STT_OBJECT
|| ELF_ST_TYPE (sym->st_info) == STT_COMMON))))
|| (d != NULL
&& h->non_elf
&& (*d->match) (&d->head, NULL, h->root.root.string)))
{
h->dynamic = 1;
/* NB: If a symbol is made dynamic by --dynamic-list, it has
non-IR reference. */
h->root.non_ir_ref_dynamic = 1;
}
}
/* Record an assignment to a symbol made by a linker script. We need
this in case some dynamic object refers to this symbol. */
bool
bfd_elf_record_link_assignment (bfd *output_bfd,
struct bfd_link_info *info,
const char *name,
bool provide,
bool hidden)
{
struct elf_link_hash_entry *h, *hv;
struct elf_link_hash_table *htab;
const struct elf_backend_data *bed;
if (!is_elf_hash_table (info->hash))
return true;
htab = elf_hash_table (info);
h = elf_link_hash_lookup (htab, name, !provide, true, false);
if (h == NULL)
return provide;
if (h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
if (h->versioned == unknown)
{
/* Set versioned if symbol version is unknown. */
char *version = strrchr (name, ELF_VER_CHR);
if (version)
{
if (version > name && version[-1] != ELF_VER_CHR)
h->versioned = versioned_hidden;
else
h->versioned = versioned;
}
}
/* Symbols defined in a linker script but not referenced anywhere
else will have non_elf set. */
if (h->non_elf)
{
bfd_elf_link_mark_dynamic_symbol (info, h, NULL);
h->non_elf = 0;
}
switch (h->root.type)
{
case bfd_link_hash_defined:
case bfd_link_hash_defweak:
case bfd_link_hash_common:
break;
case bfd_link_hash_undefweak:
case bfd_link_hash_undefined:
/* Since we're defining the symbol, don't let it seem to have not
been defined. record_dynamic_symbol and size_dynamic_sections
may depend on this. */
h->root.type = bfd_link_hash_new;
if (h->root.u.undef.next != NULL || htab->root.undefs_tail == &h->root)
bfd_link_repair_undef_list (&htab->root);
break;
case bfd_link_hash_new:
break;
case bfd_link_hash_indirect:
/* We had a versioned symbol in a dynamic library. We make the
the versioned symbol point to this one. */
bed = get_elf_backend_data (output_bfd);
hv = h;
while (hv->root.type == bfd_link_hash_indirect
|| hv->root.type == bfd_link_hash_warning)
hv = (struct elf_link_hash_entry *) hv->root.u.i.link;
/* We don't need to update h->root.u since linker will set them
later. */
h->root.type = bfd_link_hash_undefined;
hv->root.type = bfd_link_hash_indirect;
hv->root.u.i.link = (struct bfd_link_hash_entry *) h;
(*bed->elf_backend_copy_indirect_symbol) (info, h, hv);
break;
default:
BFD_FAIL ();
return false;
}
/* If this symbol is being provided by the linker script, and it is
currently defined by a dynamic object, but not by a regular
object, then mark it as undefined so that the generic linker will
force the correct value. */
if (provide
&& h->def_dynamic
&& !h->def_regular)
h->root.type = bfd_link_hash_undefined;
/* If this symbol is currently defined by a dynamic object, but not
by a regular object, then clear out any version information because
the symbol will not be associated with the dynamic object any
more. */
if (h->def_dynamic && !h->def_regular)
h->verinfo.verdef = NULL;
/* Make sure this symbol is not garbage collected. */
h->mark = 1;
h->def_regular = 1;
if (hidden)
{
bed = get_elf_backend_data (output_bfd);
if (ELF_ST_VISIBILITY (h->other) != STV_INTERNAL)
h->other = (h->other & ~ELF_ST_VISIBILITY (-1)) | STV_HIDDEN;
(*bed->elf_backend_hide_symbol) (info, h, true);
}
/* STV_HIDDEN and STV_INTERNAL symbols must be STB_LOCAL in shared objects
and executables. */
if (!bfd_link_relocatable (info)
&& h->dynindx != -1
&& (ELF_ST_VISIBILITY (h->other) == STV_HIDDEN
|| ELF_ST_VISIBILITY (h->other) == STV_INTERNAL))
h->forced_local = 1;
if ((h->def_dynamic
|| h->ref_dynamic
|| bfd_link_dll (info))
&& !h->forced_local
&& h->dynindx == -1)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return false;
/* If this is a weak defined symbol, and we know a corresponding
real symbol from the same dynamic object, make sure the real
symbol is also made into a dynamic symbol. */
if (h->is_weakalias)
{
struct elf_link_hash_entry *def = weakdef (h);
if (def->dynindx == -1
&& !bfd_elf_link_record_dynamic_symbol (info, def))
return false;
}
}
return true;
}
/* Record a new local dynamic symbol. Returns 0 on failure, 1 on
success, and 2 on a failure caused by attempting to record a symbol
in a discarded section, eg. a discarded link-once section symbol. */
int
bfd_elf_link_record_local_dynamic_symbol (struct bfd_link_info *info,
bfd *input_bfd,
long input_indx)
{
size_t amt;
struct elf_link_local_dynamic_entry *entry;
struct elf_link_hash_table *eht;
struct elf_strtab_hash *dynstr;
size_t dynstr_index;
char *name;
Elf_External_Sym_Shndx eshndx;
char esym[sizeof (Elf64_External_Sym)];
if (! is_elf_hash_table (info->hash))
return 0;
/* See if the entry exists already. */
for (entry = elf_hash_table (info)->dynlocal; entry ; entry = entry->next)
if (entry->input_bfd == input_bfd && entry->input_indx == input_indx)
return 1;
amt = sizeof (*entry);
entry = (struct elf_link_local_dynamic_entry *) bfd_alloc (input_bfd, amt);
if (entry == NULL)
return 0;
/* Go find the symbol, so that we can find it's name. */
if (!bfd_elf_get_elf_syms (input_bfd, &elf_tdata (input_bfd)->symtab_hdr,
1, input_indx, &entry->isym, esym, &eshndx))
{
bfd_release (input_bfd, entry);
return 0;
}
if (entry->isym.st_shndx != SHN_UNDEF
&& entry->isym.st_shndx < SHN_LORESERVE)
{
asection *s;
s = bfd_section_from_elf_index (input_bfd, entry->isym.st_shndx);
if (s == NULL || bfd_is_abs_section (s->output_section))
{
/* We can still bfd_release here as nothing has done another
bfd_alloc. We can't do this later in this function. */
bfd_release (input_bfd, entry);
return 2;
}
}
name = (bfd_elf_string_from_elf_section
(input_bfd, elf_tdata (input_bfd)->symtab_hdr.sh_link,
entry->isym.st_name));
dynstr = elf_hash_table (info)->dynstr;
if (dynstr == NULL)
{
/* Create a strtab to hold the dynamic symbol names. */
elf_hash_table (info)->dynstr = dynstr = _bfd_elf_strtab_init ();
if (dynstr == NULL)
return 0;
}
dynstr_index = _bfd_elf_strtab_add (dynstr, name, false);
if (dynstr_index == (size_t) -1)
return 0;
entry->isym.st_name = dynstr_index;
eht = elf_hash_table (info);
entry->next = eht->dynlocal;
eht->dynlocal = entry;
entry->input_bfd = input_bfd;
entry->input_indx = input_indx;
eht->dynsymcount++;
/* Whatever binding the symbol had before, it's now local. */
entry->isym.st_info
= ELF_ST_INFO (STB_LOCAL, ELF_ST_TYPE (entry->isym.st_info));
/* The dynindx will be set at the end of size_dynamic_sections. */
return 1;
}
/* Return the dynindex of a local dynamic symbol. */
long
_bfd_elf_link_lookup_local_dynindx (struct bfd_link_info *info,
bfd *input_bfd,
long input_indx)
{
struct elf_link_local_dynamic_entry *e;
for (e = elf_hash_table (info)->dynlocal; e ; e = e->next)
if (e->input_bfd == input_bfd && e->input_indx == input_indx)
return e->dynindx;
return -1;
}
/* This function is used to renumber the dynamic symbols, if some of
them are removed because they are marked as local. This is called
via elf_link_hash_traverse. */
static bool
elf_link_renumber_hash_table_dynsyms (struct elf_link_hash_entry *h,
void *data)
{
size_t *count = (size_t *) data;
if (h->forced_local)
return true;
if (h->dynindx != -1)
h->dynindx = ++(*count);
return true;
}
/* Like elf_link_renumber_hash_table_dynsyms, but just number symbols with
STB_LOCAL binding. */
static bool
elf_link_renumber_local_hash_table_dynsyms (struct elf_link_hash_entry *h,
void *data)
{
size_t *count = (size_t *) data;
if (!h->forced_local)
return true;
if (h->dynindx != -1)
h->dynindx = ++(*count);
return true;
}
/* Return true if the dynamic symbol for a given section should be
omitted when creating a shared library. */
bool
_bfd_elf_omit_section_dynsym_default (bfd *output_bfd ATTRIBUTE_UNUSED,
struct bfd_link_info *info,
asection *p)
{
struct elf_link_hash_table *htab;
asection *ip;
switch (elf_section_data (p)->this_hdr.sh_type)
{
case SHT_PROGBITS:
case SHT_NOBITS:
/* If sh_type is yet undecided, assume it could be
SHT_PROGBITS/SHT_NOBITS. */
case SHT_NULL:
htab = elf_hash_table (info);
if (htab->text_index_section != NULL)
return p != htab->text_index_section && p != htab->data_index_section;
return (htab->dynobj != NULL
&& (ip = bfd_get_linker_section (htab->dynobj, p->name)) != NULL
&& ip->output_section == p);
/* There shouldn't be section relative relocations
against any other section. */
default:
return true;
}
}
bool
_bfd_elf_omit_section_dynsym_all
(bfd *output_bfd ATTRIBUTE_UNUSED,
struct bfd_link_info *info ATTRIBUTE_UNUSED,
asection *p ATTRIBUTE_UNUSED)
{
return true;
}
/* Assign dynsym indices. In a shared library we generate a section
symbol for each output section, which come first. Next come symbols
which have been forced to local binding. Then all of the back-end
allocated local dynamic syms, followed by the rest of the global
symbols. If SECTION_SYM_COUNT is NULL, section dynindx is not set.
(This prevents the early call before elf_backend_init_index_section
and strip_excluded_output_sections setting dynindx for sections
that are stripped.) */
static unsigned long
_bfd_elf_link_renumber_dynsyms (bfd *output_bfd,
struct bfd_link_info *info,
unsigned long *section_sym_count)
{
unsigned long dynsymcount = 0;
bool do_sec = section_sym_count != NULL;
if (bfd_link_pic (info)
|| elf_hash_table (info)->is_relocatable_executable)
{
const struct elf_backend_data *bed = get_elf_backend_data (output_bfd);
asection *p;
for (p = output_bfd->sections; p ; p = p->next)
if ((p->flags & SEC_EXCLUDE) == 0
&& (p->flags & SEC_ALLOC) != 0
&& elf_hash_table (info)->dynamic_relocs
&& !(*bed->elf_backend_omit_section_dynsym) (output_bfd, info, p))
{
++dynsymcount;
if (do_sec)
elf_section_data (p)->dynindx = dynsymcount;
}
else if (do_sec)
elf_section_data (p)->dynindx = 0;
}
if (do_sec)
*section_sym_count = dynsymcount;
elf_link_hash_traverse (elf_hash_table (info),
elf_link_renumber_local_hash_table_dynsyms,
&dynsymcount);
if (elf_hash_table (info)->dynlocal)
{
struct elf_link_local_dynamic_entry *p;
for (p = elf_hash_table (info)->dynlocal; p ; p = p->next)
p->dynindx = ++dynsymcount;
}
elf_hash_table (info)->local_dynsymcount = dynsymcount;
elf_link_hash_traverse (elf_hash_table (info),
elf_link_renumber_hash_table_dynsyms,
&dynsymcount);
/* There is an unused NULL entry at the head of the table which we
must account for in our count even if the table is empty since it
is intended for the mandatory DT_SYMTAB tag (.dynsym section) in
.dynamic section. */
dynsymcount++;
elf_hash_table (info)->dynsymcount = dynsymcount;
return dynsymcount;
}
/* Merge st_other field. */
static void
elf_merge_st_other (bfd *abfd, struct elf_link_hash_entry *h,
unsigned int st_other, asection *sec,
bool definition, bool dynamic)
{
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
/* If st_other has a processor-specific meaning, specific
code might be needed here. */
if (bed->elf_backend_merge_symbol_attribute)
(*bed->elf_backend_merge_symbol_attribute) (h, st_other, definition,
dynamic);
if (!dynamic)
{
unsigned symvis = ELF_ST_VISIBILITY (st_other);
unsigned hvis = ELF_ST_VISIBILITY (h->other);
/* Keep the most constraining visibility. Leave the remainder
of the st_other field to elf_backend_merge_symbol_attribute. */
if (symvis - 1 < hvis - 1)
h->other = symvis | (h->other & ~ELF_ST_VISIBILITY (-1));
}
else if (definition
&& ELF_ST_VISIBILITY (st_other) != STV_DEFAULT
&& (sec->flags & SEC_READONLY) == 0)
h->protected_def = 1;
}
/* This function is called when we want to merge a new symbol with an
existing symbol. It handles the various cases which arise when we
find a definition in a dynamic object, or when there is already a
definition in a dynamic object. The new symbol is described by
NAME, SYM, PSEC, and PVALUE. We set SYM_HASH to the hash table
entry. We set POLDBFD to the old symbol's BFD. We set POLD_WEAK
if the old symbol was weak. We set POLD_ALIGNMENT to the alignment
of an old common symbol. We set OVERRIDE if the old symbol is
overriding a new definition. We set TYPE_CHANGE_OK if it is OK for
the type to change. We set SIZE_CHANGE_OK if it is OK for the size
to change. By OK to change, we mean that we shouldn't warn if the
type or size does change. */
static bool
_bfd_elf_merge_symbol (bfd *abfd,
struct bfd_link_info *info,
const char *name,
Elf_Internal_Sym *sym,
asection **psec,
bfd_vma *pvalue,
struct elf_link_hash_entry **sym_hash,
bfd **poldbfd,
bool *pold_weak,
unsigned int *pold_alignment,
bool *skip,
bfd **override,
bool *type_change_ok,
bool *size_change_ok,
bool *matched)
{
asection *sec, *oldsec;
struct elf_link_hash_entry *h;
struct elf_link_hash_entry *hi;
struct elf_link_hash_entry *flip;
int bind;
bfd *oldbfd;
bool newdyn, olddyn, olddef, newdef, newdyncommon, olddyncommon;
bool newweak, oldweak, newfunc, oldfunc;
const struct elf_backend_data *bed;
char *new_version;
bool default_sym = *matched;
struct elf_link_hash_table *htab;
*skip = false;
*override = NULL;
sec = *psec;
bind = ELF_ST_BIND (sym->st_info);
if (! bfd_is_und_section (sec))
h = elf_link_hash_lookup (elf_hash_table (info), name, true, false, false);
else
h = ((struct elf_link_hash_entry *)
bfd_wrapped_link_hash_lookup (abfd, info, name, true, false, false));
if (h == NULL)
return false;
*sym_hash = h;
bed = get_elf_backend_data (abfd);
/* NEW_VERSION is the symbol version of the new symbol. */
if (h->versioned != unversioned)
{
/* Symbol version is unknown or versioned. */
new_version = strrchr (name, ELF_VER_CHR);
if (new_version)
{
if (h->versioned == unknown)
{
if (new_version > name && new_version[-1] != ELF_VER_CHR)
h->versioned = versioned_hidden;
else
h->versioned = versioned;
}
new_version += 1;
if (new_version[0] == '\0')
new_version = NULL;
}
else
h->versioned = unversioned;
}
else
new_version = NULL;
/* For merging, we only care about real symbols. But we need to make
sure that indirect symbol dynamic flags are updated. */
hi = h;
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 (!*matched)
{
if (hi == h || h->root.type == bfd_link_hash_new)
*matched = true;
else
{
/* OLD_HIDDEN is true if the existing symbol is only visible
to the symbol with the same symbol version. NEW_HIDDEN is
true if the new symbol is only visible to the symbol with
the same symbol version. */
bool old_hidden = h->versioned == versioned_hidden;
bool new_hidden = hi->versioned == versioned_hidden;
if (!old_hidden && !new_hidden)
/* The new symbol matches the existing symbol if both
aren't hidden. */
*matched = true;
else
{
/* OLD_VERSION is the symbol version of the existing
symbol. */
char *old_version;
if (h->versioned >= versioned)
old_version = strrchr (h->root.root.string,
ELF_VER_CHR) + 1;
else
old_version = NULL;
/* The new symbol matches the existing symbol if they
have the same symbol version. */
*matched = (old_version == new_version
|| (old_version != NULL
&& new_version != NULL
&& strcmp (old_version, new_version) == 0));
}
}
}
/* OLDBFD and OLDSEC are a BFD and an ASECTION associated with the
existing symbol. */
oldbfd = NULL;
oldsec = NULL;
switch (h->root.type)
{
default:
break;
case bfd_link_hash_undefined:
case bfd_link_hash_undefweak:
oldbfd = h->root.u.undef.abfd;
break;
case bfd_link_hash_defined:
case bfd_link_hash_defweak:
oldbfd = h->root.u.def.section->owner;
oldsec = h->root.u.def.section;
break;
case bfd_link_hash_common:
oldbfd = h->root.u.c.p->section->owner;
oldsec = h->root.u.c.p->section;
if (pold_alignment)
*pold_alignment = h->root.u.c.p->alignment_power;
break;
}
if (poldbfd && *poldbfd == NULL)
*poldbfd = oldbfd;
/* Differentiate strong and weak symbols. */
newweak = bind == STB_WEAK;
oldweak = (h->root.type == bfd_link_hash_defweak
|| h->root.type == bfd_link_hash_undefweak);
if (pold_weak)
*pold_weak = oldweak;
/* We have to check it for every instance since the first few may be
references and not all compilers emit symbol type for undefined
symbols. */
bfd_elf_link_mark_dynamic_symbol (info, h, sym);
htab = elf_hash_table (info);
/* NEWDYN and OLDDYN indicate whether the new or old symbol,
respectively, is from a dynamic object. */
newdyn = (abfd->flags & DYNAMIC) != 0;
/* ref_dynamic_nonweak and dynamic_def flags track actual undefined
syms and defined syms in dynamic libraries respectively.
ref_dynamic on the other hand can be set for a symbol defined in
a dynamic library, and def_dynamic may not be set; When the
definition in a dynamic lib is overridden by a definition in the
executable use of the symbol in the dynamic lib becomes a
reference to the executable symbol. */
if (newdyn)
{
if (bfd_is_und_section (sec))
{
if (bind != STB_WEAK)
{
h->ref_dynamic_nonweak = 1;
hi->ref_dynamic_nonweak = 1;
}
}
else
{
/* Update the existing symbol only if they match. */
if (*matched)
h->dynamic_def = 1;
hi->dynamic_def = 1;
}
}
/* If we just created the symbol, mark it as being an ELF symbol.
Other than that, there is nothing to do--there is no merge issue
with a newly defined symbol--so we just return. */
if (h->root.type == bfd_link_hash_new)
{
h->non_elf = 0;
return true;
}
/* In cases involving weak versioned symbols, we may wind up trying
to merge a symbol with itself. Catch that here, to avoid the
confusion that results if we try to override a symbol with
itself. The additional tests catch cases like
_GLOBAL_OFFSET_TABLE_, which are regular symbols defined in a
dynamic object, which we do want to handle here. */
if (abfd == oldbfd
&& (newweak || oldweak)
&& ((abfd->flags & DYNAMIC) == 0
|| !h->def_regular))
return true;
olddyn = false;
if (oldbfd != NULL)
olddyn = (oldbfd->flags & DYNAMIC) != 0;
else if (oldsec != NULL)
{
/* This handles the special SHN_MIPS_{TEXT,DATA} section
indices used by MIPS ELF. */
olddyn = (oldsec->symbol->flags & BSF_DYNAMIC) != 0;
}
/* Set non_ir_ref_dynamic only when not handling DT_NEEDED entries. */
if (!htab->handling_dt_needed
&& oldbfd != NULL
&& (oldbfd->flags & BFD_PLUGIN) != (abfd->flags & BFD_PLUGIN))
{
if (newdyn != olddyn)
{
/* Handle a case where plugin_notice won't be called and thus
won't set the non_ir_ref flags on the first pass over
symbols. */
h->root.non_ir_ref_dynamic = true;
hi->root.non_ir_ref_dynamic = true;
}
else if ((oldbfd->flags & BFD_PLUGIN) != 0
&& hi->root.type == bfd_link_hash_indirect)
{
/* Change indirect symbol from IR to undefined. */
hi->root.type = bfd_link_hash_undefined;
hi->root.u.undef.abfd = oldbfd;
}
}
/* NEWDEF and OLDDEF indicate whether the new or old symbol,
respectively, appear to be a definition rather than reference. */
newdef = !bfd_is_und_section (sec) && !bfd_is_com_section (sec);
olddef = (h->root.type != bfd_link_hash_undefined
&& h->root.type != bfd_link_hash_undefweak
&& h->root.type != bfd_link_hash_common);
/* NEWFUNC and OLDFUNC indicate whether the new or old symbol,
respectively, appear to be a function. */
newfunc = (ELF_ST_TYPE (sym->st_info) != STT_NOTYPE
&& bed->is_function_type (ELF_ST_TYPE (sym->st_info)));
oldfunc = (h->type != STT_NOTYPE
&& bed->is_function_type (h->type));
if (!(newfunc && oldfunc)
&& ELF_ST_TYPE (sym->st_info) != h->type
&& ELF_ST_TYPE (sym->st_info) != STT_NOTYPE
&& h->type != STT_NOTYPE
&& (newdef || bfd_is_com_section (sec))
&& (olddef || h->root.type == bfd_link_hash_common))
{
/* If creating a default indirect symbol ("foo" or "foo@") from
a dynamic versioned definition ("foo@@") skip doing so if
there is an existing regular definition with a different
type. We don't want, for example, a "time" variable in the
executable overriding a "time" function in a shared library. */
if (newdyn
&& !olddyn)
{
*skip = true;
return true;
}
/* When adding a symbol from a regular object file after we have
created indirect symbols, undo the indirection and any
dynamic state. */
if (hi != h
&& !newdyn
&& olddyn)
{
h = hi;
(*bed->elf_backend_hide_symbol) (info, h, true);
h->forced_local = 0;
h->ref_dynamic = 0;
h->def_dynamic = 0;
h->dynamic_def = 0;
if (h->root.u.undef.next || info->hash->undefs_tail == &h->root)
{
h->root.type = bfd_link_hash_undefined;
h->root.u.undef.abfd = abfd;
}
else
{
h->root.type = bfd_link_hash_new;
h->root.u.undef.abfd = NULL;
}
return true;
}
}
/* Check TLS symbols. We don't check undefined symbols introduced
by "ld -u" which have no type (and oldbfd NULL), and we don't
check symbols from plugins because they also have no type. */
if (oldbfd != NULL
&& (oldbfd->flags & BFD_PLUGIN) == 0
&& (abfd->flags & BFD_PLUGIN) == 0
&& ELF_ST_TYPE (sym->st_info) != h->type
&& (ELF_ST_TYPE (sym->st_info) == STT_TLS || h->type == STT_TLS))
{
bfd *ntbfd, *tbfd;
bool ntdef, tdef;
asection *ntsec, *tsec;
if (h->type == STT_TLS)
{
ntbfd = abfd;
ntsec = sec;
ntdef = newdef;
tbfd = oldbfd;
tsec = oldsec;
tdef = olddef;
}
else
{
ntbfd = oldbfd;
ntsec = oldsec;
ntdef = olddef;
tbfd = abfd;
tsec = sec;
tdef = newdef;
}
if (tdef && ntdef)
_bfd_error_handler
/* xgettext:c-format */
(_("%s: TLS definition in %pB section %pA "
"mismatches non-TLS definition in %pB section %pA"),
h->root.root.string, tbfd, tsec, ntbfd, ntsec);
else if (!tdef && !ntdef)
_bfd_error_handler
/* xgettext:c-format */
(_("%s: TLS reference in %pB "
"mismatches non-TLS reference in %pB"),
h->root.root.string, tbfd, ntbfd);
else if (tdef)
_bfd_error_handler
/* xgettext:c-format */
(_("%s: TLS definition in %pB section %pA "
"mismatches non-TLS reference in %pB"),
h->root.root.string, tbfd, tsec, ntbfd);
else
_bfd_error_handler
/* xgettext:c-format */
(_("%s: TLS reference in %pB "
"mismatches non-TLS definition in %pB section %pA"),
h->root.root.string, tbfd, ntbfd, ntsec);
bfd_set_error (bfd_error_bad_value);
return false;
}
/* If the old symbol has non-default visibility, we ignore the new
definition from a dynamic object. */
if (newdyn
&& ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
&& !bfd_is_und_section (sec))
{
*skip = true;
/* Make sure this symbol is dynamic. */
h->ref_dynamic = 1;
hi->ref_dynamic = 1;
/* A protected symbol has external availability. Make sure it is
recorded as dynamic.
FIXME: Should we check type and size for protected symbol? */
if (ELF_ST_VISIBILITY (h->other) == STV_PROTECTED)
return bfd_elf_link_record_dynamic_symbol (info, h);
else
return true;
}
else if (!newdyn
&& ELF_ST_VISIBILITY (sym->st_other) != STV_DEFAULT
&& h->def_dynamic)
{
/* If the new symbol with non-default visibility comes from a
relocatable file and the old definition comes from a dynamic
object, we remove the old definition. */
if (hi->root.type == bfd_link_hash_indirect)
{
/* Handle the case where the old dynamic definition is
default versioned. We need to copy the symbol info from
the symbol with default version to the normal one if it
was referenced before. */
if (h->ref_regular)
{
hi->root.type = h->root.type;
h->root.type = bfd_link_hash_indirect;
(*bed->elf_backend_copy_indirect_symbol) (info, hi, h);
h->root.u.i.link = (struct bfd_link_hash_entry *) hi;
if (ELF_ST_VISIBILITY (sym->st_other) != STV_PROTECTED)
{
/* If the new symbol is hidden or internal, completely undo
any dynamic link state. */
(*bed->elf_backend_hide_symbol) (info, h, true);
h->forced_local = 0;
h->ref_dynamic = 0;
}
else
h->ref_dynamic = 1;
h->def_dynamic = 0;
/* FIXME: Should we check type and size for protected symbol? */
h->size = 0;
h->type = 0;
h = hi;
}
else
h = hi;
}
/* If the old symbol was undefined before, then it will still be
on the undefs list. If the new symbol is undefined or
common, we can't make it bfd_link_hash_new here, because new
undefined or common symbols will be added to the undefs list
by _bfd_generic_link_add_one_symbol. Symbols may not be
added twice to the undefs list. Also, if the new symbol is
undefweak then we don't want to lose the strong undef. */
if (h->root.u.undef.next || info->hash->undefs_tail == &h->root)
{
h->root.type = bfd_link_hash_undefined;
h->root.u.undef.abfd = abfd;
}
else
{
h->root.type = bfd_link_hash_new;
h->root.u.undef.abfd = NULL;
}
if (ELF_ST_VISIBILITY (sym->st_other) != STV_PROTECTED)
{
/* If the new symbol is hidden or internal, completely undo
any dynamic link state. */
(*bed->elf_backend_hide_symbol) (info, h, true);
h->forced_local = 0;
h->ref_dynamic = 0;
}
else
h->ref_dynamic = 1;
h->def_dynamic = 0;
/* FIXME: Should we check type and size for protected symbol? */
h->size = 0;
h->type = 0;
return true;
}
/* If a new weak symbol definition comes from a regular file and the
old symbol comes from a dynamic library, we treat the new one as
strong. Similarly, an old weak symbol definition from a regular
file is treated as strong when the new symbol comes from a dynamic
library. Further, an old weak symbol from a dynamic library is
treated as strong if the new symbol is from a dynamic library.
This reflects the way glibc's ld.so works.
Also allow a weak symbol to override a linker script symbol
defined by an early pass over the script. This is done so the
linker knows the symbol is defined in an object file, for the
DEFINED script function.
Do this before setting *type_change_ok or *size_change_ok so that
we warn properly when dynamic library symbols are overridden. */
if (newdef && !newdyn && (olddyn || h->root.ldscript_def))
newweak = false;
if (olddef && newdyn)
oldweak = false;
/* Allow changes between different types of function symbol. */
if (newfunc && oldfunc)
*type_change_ok = true;
/* It's OK to change the type if either the existing symbol or the
new symbol is weak. A type change is also OK if the old symbol
is undefined and the new symbol is defined. */
if (oldweak
|| newweak
|| (newdef
&& h->root.type == bfd_link_hash_undefined))
*type_change_ok = true;
/* It's OK to change the size if either the existing symbol or the
new symbol is weak, or if the old symbol is undefined. */
if (*type_change_ok
|| h->root.type == bfd_link_hash_undefined)
*size_change_ok = true;
/* NEWDYNCOMMON and OLDDYNCOMMON indicate whether the new or old
symbol, respectively, appears to be a common symbol in a dynamic
object. If a symbol appears in an uninitialized section, and is
not weak, and is not a function, then it may be a common symbol
which was resolved when the dynamic object was created. We want
to treat such symbols specially, because they raise special
considerations when setting the symbol size: if the symbol
appears as a common symbol in a regular object, and the size in
the regular object is larger, we must make sure that we use the
larger size. This problematic case can always be avoided in C,
but it must be handled correctly when using Fortran shared
libraries.
Note that if NEWDYNCOMMON is set, NEWDEF will be set, and
likewise for OLDDYNCOMMON and OLDDEF.
Note that this test is just a heuristic, and that it is quite
possible to have an uninitialized symbol in a shared object which
is really a definition, rather than a common symbol. This could
lead to some minor confusion when the symbol really is a common
symbol in some regular object. However, I think it will be
harmless. */
if (newdyn
&& newdef
&& !newweak
&& (sec->flags & SEC_ALLOC) != 0
&& (sec->flags & SEC_LOAD) == 0
&& sym->st_size > 0
&& !newfunc)
newdyncommon = true;
else
newdyncommon = false;
if (olddyn
&& olddef
&& h->root.type == bfd_link_hash_defined
&& h->def_dynamic
&& (h->root.u.def.section->flags & SEC_ALLOC) != 0
&& (h->root.u.def.section->flags & SEC_LOAD) == 0
&& h->size > 0
&& !oldfunc)
olddyncommon = true;
else
olddyncommon = false;
/* We now know everything about the old and new symbols. We ask the
backend to check if we can merge them. */
if (bed->merge_symbol != NULL)
{
if (!bed->merge_symbol (h, sym, psec, newdef, olddef, oldbfd, oldsec))
return false;
sec = *psec;
}
/* There are multiple definitions of a normal symbol. Skip the
default symbol as well as definition from an IR object. */
if (olddef && !olddyn && !oldweak && newdef && !newdyn && !newweak
&& !default_sym && h->def_regular
&& !(oldbfd != NULL
&& (oldbfd->flags & BFD_PLUGIN) != 0
&& (abfd->flags & BFD_PLUGIN) == 0))
{
/* Handle a multiple definition. */
(*info->callbacks->multiple_definition) (info, &h->root,
abfd, sec, *pvalue);
*skip = true;
return true;
}
/* If both the old and the new symbols look like common symbols in a
dynamic object, set the size of the symbol to the larger of the
two. */
if (olddyncommon
&& newdyncommon
&& sym->st_size != h->size)
{
/* Since we think we have two common symbols, issue a multiple
common warning if desired. Note that we only warn if the
size is different. If the size is the same, we simply let
the old symbol override the new one as normally happens with
symbols defined in dynamic objects. */
(*info->callbacks->multiple_common) (info, &h->root, abfd,
bfd_link_hash_common, sym->st_size);
if (sym->st_size > h->size)
h->size = sym->st_size;
*size_change_ok = true;
}
/* If we are looking at a dynamic object, and we have found a
definition, we need to see if the symbol was already defined by
some other object. If so, we want to use the existing
definition, and we do not want to report a multiple symbol
definition error; we do this by clobbering *PSEC to be
bfd_und_section_ptr.
We treat a common symbol as a definition if the symbol in the
shared library is a function, since common symbols always
represent variables; this can cause confusion in principle, but
any such confusion would seem to indicate an erroneous program or
shared library. We also permit a common symbol in a regular
object to override a weak symbol in a shared object. */
if (newdyn
&& newdef
&& (olddef
|| (h->root.type == bfd_link_hash_common
&& (newweak || newfunc))))
{
*override = abfd;
newdef = false;
newdyncommon = false;
*psec = sec = bfd_und_section_ptr;
*size_change_ok = true;
/* If we get here when the old symbol is a common symbol, then
we are explicitly letting it override a weak symbol or
function in a dynamic object, and we don't want to warn about
a type change. If the old symbol is a defined symbol, a type
change warning may still be appropriate. */
if (h->root.type == bfd_link_hash_common)
*type_change_ok = true;
}
/* Handle the special case of an old common symbol merging with a
new symbol which looks like a common symbol in a shared object.
We change *PSEC and *PVALUE to make the new symbol look like a
common symbol, and let _bfd_generic_link_add_one_symbol do the
right thing. */
if (newdyncommon
&& h->root.type == bfd_link_hash_common)
{
*override = oldbfd;
newdef = false;
newdyncommon = false;
*pvalue = sym->st_size;
*psec = sec = bed->common_section (oldsec);
*size_change_ok = true;
}
/* Skip weak definitions of symbols that are already defined. */
if (newdef && olddef && newweak)
{
/* Don't skip new non-IR weak syms. */
if (!(oldbfd != NULL
&& (oldbfd->flags & BFD_PLUGIN) != 0
&& (abfd->flags & BFD_PLUGIN) == 0))
{
newdef = false;
*skip = true;
}
/* Merge st_other. If the symbol already has a dynamic index,
but visibility says it should not be visible, turn it into a
local symbol. */
elf_merge_st_other (abfd, h, sym->st_other, sec, newdef, newdyn);
if (h->dynindx != -1)
switch (ELF_ST_VISIBILITY (h->other))
{
case STV_INTERNAL:
case STV_HIDDEN:
(*bed->elf_backend_hide_symbol) (info, h, true);
break;
}
}
/* If the old symbol is from a dynamic object, and the new symbol is
a definition which is not from a dynamic object, then the new
symbol overrides the old symbol. Symbols from regular files
always take precedence over symbols from dynamic objects, even if
they are defined after the dynamic object in the link.
As above, we again permit a common symbol in a regular object to
override a definition in a shared object if the shared object
symbol is a function or is weak. */
flip = NULL;
if (!newdyn
&& (newdef
|| (bfd_is_com_section (sec)
&& (oldweak || oldfunc)))
&& olddyn
&& olddef
&& h->def_dynamic)
{
/* Change the hash table entry to undefined, and let
_bfd_generic_link_add_one_symbol do the right thing with the
new definition. */
h->root.type = bfd_link_hash_undefined;
h->root.u.undef.abfd = h->root.u.def.section->owner;
*size_change_ok = true;
olddef = false;
olddyncommon = false;
/* We again permit a type change when a common symbol may be
overriding a function. */
if (bfd_is_com_section (sec))
{
if (oldfunc)
{
/* If a common symbol overrides a function, make sure
that it isn't defined dynamically nor has type
function. */
h->def_dynamic = 0;
h->type = STT_NOTYPE;
}
*type_change_ok = true;
}
if (hi->root.type == bfd_link_hash_indirect)
flip = hi;
else
/* This union may have been set to be non-NULL when this symbol
was seen in a dynamic object. We must force the union to be
NULL, so that it is correct for a regular symbol. */
h->verinfo.vertree = NULL;
}
/* Handle the special case of a new common symbol merging with an
old symbol that looks like it might be a common symbol defined in
a shared object. Note that we have already handled the case in
which a new common symbol should simply override the definition
in the shared library. */
if (! newdyn
&& bfd_is_com_section (sec)
&& olddyncommon)
{
/* It would be best if we could set the hash table entry to a
common symbol, but we don't know what to use for the section
or the alignment. */
(*info->callbacks->multiple_common) (info, &h->root, abfd,
bfd_link_hash_common, sym->st_size);
/* If the presumed common symbol in the dynamic object is
larger, pretend that the new symbol has its size. */
if (h->size > *pvalue)
*pvalue = h->size;
/* We need to remember the alignment required by the symbol
in the dynamic object. */
BFD_ASSERT (pold_alignment);
*pold_alignment = h->root.u.def.section->alignment_power;
olddef = false;
olddyncommon = false;
h->root.type = bfd_link_hash_undefined;
h->root.u.undef.abfd = h->root.u.def.section->owner;
*size_change_ok = true;
*type_change_ok = true;
if (hi->root.type == bfd_link_hash_indirect)
flip = hi;
else
h->verinfo.vertree = NULL;
}
if (flip != NULL)
{
/* Handle the case where we had a versioned symbol in a dynamic
library and now find a definition in a normal object. In this
case, we make the versioned symbol point to the normal one. */
flip->root.type = h->root.type;
flip->root.u.undef.abfd = h->root.u.undef.abfd;
h->root.type = bfd_link_hash_indirect;
h->root.u.i.link = (struct bfd_link_hash_entry *) flip;
(*bed->elf_backend_copy_indirect_symbol) (info, flip, h);
if (h->def_dynamic)
{
h->def_dynamic = 0;
flip->ref_dynamic = 1;
}
}
return true;
}
/* This function is called to create an indirect symbol from the
default for the symbol with the default version if needed. The
symbol is described by H, NAME, SYM, SEC, and VALUE. We
set DYNSYM if the new indirect symbol is dynamic. */
static bool
_bfd_elf_add_default_symbol (bfd *abfd,
struct bfd_link_info *info,
struct elf_link_hash_entry *h,
const char *name,
Elf_Internal_Sym *sym,
asection *sec,
bfd_vma value,
bfd **poldbfd,
bool *dynsym)
{
bool type_change_ok;
bool size_change_ok;
bool skip;
char *shortname;
struct elf_link_hash_entry *hi;
struct bfd_link_hash_entry *bh;
const struct elf_backend_data *bed;
bool collect;
bool dynamic;
bfd *override;
char *p;
size_t len, shortlen;
asection *tmp_sec;
bool matched;
if (h->versioned == unversioned || h->versioned == versioned_hidden)
return true;
/* If this symbol has a version, and it is the default version, we
create an indirect symbol from the default name to the fully
decorated name. This will cause external references which do not
specify a version to be bound to this version of the symbol. */
p = strchr (name, ELF_VER_CHR);
if (h->versioned == unknown)
{
if (p == NULL)
{
h->versioned = unversioned;
return true;
}
else
{
if (p[1] != ELF_VER_CHR)
{
h->versioned = versioned_hidden;
return true;
}
else
h->versioned = versioned;
}
}
else
{
/* PR ld/19073: We may see an unversioned definition after the
default version. */
if (p == NULL)
return true;
}
bed = get_elf_backend_data (abfd);
collect = bed->collect;
dynamic = (abfd->flags & DYNAMIC) != 0;
shortlen = p - name;
shortname = (char *) bfd_hash_allocate (&info->hash->table, shortlen + 1);
if (shortname == NULL)
return false;
memcpy (shortname, name, shortlen);
shortname[shortlen] = '\0';
/* We are going to create a new symbol. Merge it with any existing
symbol with this name. For the purposes of the merge, act as
though we were defining the symbol we just defined, although we
actually going to define an indirect symbol. */
type_change_ok = false;
size_change_ok = false;
matched = true;
tmp_sec = sec;
if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &tmp_sec, &value,
&hi, poldbfd, NULL, NULL, &skip, &override,
&type_change_ok, &size_change_ok, &matched))
return false;
if (skip)
goto nondefault;
if (hi->def_regular || ELF_COMMON_DEF_P (hi))
{
/* If the undecorated symbol will have a version added by a
script different to H, then don't indirect to/from the
undecorated symbol. This isn't ideal because we may not yet
have seen symbol versions, if given by a script on the
command line rather than via --version-script. */
if (hi->verinfo.vertree == NULL && info->version_info != NULL)
{
bool hide;
hi->verinfo.vertree
= bfd_find_version_for_sym (info->version_info,
hi->root.root.string, &hide);
if (hi->verinfo.vertree != NULL && hide)
{
(*bed->elf_backend_hide_symbol) (info, hi, true);
goto nondefault;
}
}
if (hi->verinfo.vertree != NULL
&& strcmp (p + 1 + (p[1] == '@'), hi->verinfo.vertree->name) != 0)
goto nondefault;
}
if (! override)
{
/* Add the default symbol if not performing a relocatable link. */
if (! bfd_link_relocatable (info))
{
bh = &hi->root;
if (bh->type == bfd_link_hash_defined
&& bh->u.def.section->owner != NULL
&& (bh->u.def.section->owner->flags & BFD_PLUGIN) != 0)
{
/* Mark the previous definition from IR object as
undefined so that the generic linker will override
it. */
bh->type = bfd_link_hash_undefined;
bh->u.undef.abfd = bh->u.def.section->owner;
}
if (! (_bfd_generic_link_add_one_symbol
(info, abfd, shortname, BSF_INDIRECT,
bfd_ind_section_ptr,
0, name, false, collect, &bh)))
return false;
hi = (struct elf_link_hash_entry *) bh;
}
}
else
{
/* In this case the symbol named SHORTNAME is overriding the
indirect symbol we want to add. We were planning on making
SHORTNAME an indirect symbol referring to NAME. SHORTNAME
is the name without a version. NAME is the fully versioned
name, and it is the default version.
Overriding means that we already saw a definition for the
symbol SHORTNAME in a regular object, and it is overriding
the symbol defined in the dynamic object.
When this happens, we actually want to change NAME, the
symbol we just added, to refer to SHORTNAME. This will cause
references to NAME in the shared object to become references
to SHORTNAME in the regular object. This is what we expect
when we override a function in a shared object: that the
references in the shared object will be mapped to the
definition in the regular object. */
while (hi->root.type == bfd_link_hash_indirect
|| hi->root.type == bfd_link_hash_warning)
hi = (struct elf_link_hash_entry *) hi->root.u.i.link;
h->root.type = bfd_link_hash_indirect;
h->root.u.i.link = (struct bfd_link_hash_entry *) hi;
if (h->def_dynamic)
{
h->def_dynamic = 0;
hi->ref_dynamic = 1;
if (hi->ref_regular
|| hi->def_regular)
{
if (! bfd_elf_link_record_dynamic_symbol (info, hi))
return false;
}
}
/* Now set HI to H, so that the following code will set the
other fields correctly. */
hi = h;
}
/* Check if HI is a warning symbol. */
if (hi->root.type == bfd_link_hash_warning)
hi = (struct elf_link_hash_entry *) hi->root.u.i.link;
/* If there is a duplicate definition somewhere, then HI may not
point to an indirect symbol. We will have reported an error to
the user in that case. */
if (hi->root.type == bfd_link_hash_indirect)
{
struct elf_link_hash_entry *ht;
ht = (struct elf_link_hash_entry *) hi->root.u.i.link;
(*bed->elf_backend_copy_indirect_symbol) (info, ht, hi);
/* If we first saw a reference to SHORTNAME with non-default
visibility, merge that visibility to the @@VER symbol. */
elf_merge_st_other (abfd, ht, hi->other, sec, true, dynamic);
/* A reference to the SHORTNAME symbol from a dynamic library
will be satisfied by the versioned symbol at runtime. In
effect, we have a reference to the versioned symbol. */
ht->ref_dynamic_nonweak |= hi->ref_dynamic_nonweak;
hi->dynamic_def |= ht->dynamic_def;
/* See if the new flags lead us to realize that the symbol must
be dynamic. */
if (! *dynsym)
{
if (! dynamic)
{
if (! bfd_link_executable (info)
|| hi->def_dynamic
|| hi->ref_dynamic)
*dynsym = true;
}
else
{
if (hi->ref_regular)
*dynsym = true;
}
}
}
/* We also need to define an indirection from the nondefault version
of the symbol. */
nondefault:
len = strlen (name);
shortname = (char *) bfd_hash_allocate (&info->hash->table, len);
if (shortname == NULL)
return false;
memcpy (shortname, name, shortlen);
memcpy (shortname + shortlen, p + 1, len - shortlen);
/* Once again, merge with any existing symbol. */
type_change_ok = false;
size_change_ok = false;
tmp_sec = sec;
if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &tmp_sec, &value,
&hi, poldbfd, NULL, NULL, &skip, &override,
&type_change_ok, &size_change_ok, &matched))
return false;
if (skip)
{
if (!dynamic
&& h->root.type == bfd_link_hash_defweak
&& hi->root.type == bfd_link_hash_defined)
{
/* We are handling a weak sym@@ver and attempting to define
a weak sym@ver, but _bfd_elf_merge_symbol said to skip the
new weak sym@ver because there is already a strong sym@ver.
However, sym@ver and sym@@ver are really the same symbol.
The existing strong sym@ver ought to override sym@@ver. */
h->root.type = bfd_link_hash_defined;
h->root.u.def.section = hi->root.u.def.section;
h->root.u.def.value = hi->root.u.def.value;
hi->root.type = bfd_link_hash_indirect;
hi->root.u.i.link = &h->root;
}
else
return true;
}
else if (override)
{
/* Here SHORTNAME is a versioned name, so we don't expect to see
the type of override we do in the case above unless it is
overridden by a versioned definition. */
if (hi->root.type != bfd_link_hash_defined
&& hi->root.type != bfd_link_hash_defweak)
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: unexpected redefinition of indirect versioned symbol `%s'"),
abfd, shortname);
return true;
}
else
{
bh = &hi->root;
if (! (_bfd_generic_link_add_one_symbol
(info, abfd, shortname, BSF_INDIRECT,
bfd_ind_section_ptr, 0, name, false, collect, &bh)))
return false;
hi = (struct elf_link_hash_entry *) bh;
}
/* If there is a duplicate definition somewhere, then HI may not
point to an indirect symbol. We will have reported an error
to the user in that case. */
if (hi->root.type == bfd_link_hash_indirect)
{
(*bed->elf_backend_copy_indirect_symbol) (info, h, hi);
h->ref_dynamic_nonweak |= hi->ref_dynamic_nonweak;
hi->dynamic_def |= h->dynamic_def;
/* If we first saw a reference to @VER symbol with
non-default visibility, merge that visibility to the
@@VER symbol. */
elf_merge_st_other (abfd, h, hi->other, sec, true, dynamic);
/* See if the new flags lead us to realize that the symbol
must be dynamic. */
if (! *dynsym)
{
if (! dynamic)
{
if (! bfd_link_executable (info)
|| hi->ref_dynamic)
*dynsym = true;
}
else
{
if (hi->ref_regular)
*dynsym = true;
}
}
}
return true;
}
/* This routine is used to export all defined symbols into the dynamic
symbol table. It is called via elf_link_hash_traverse. */
static bool
_bfd_elf_export_symbol (struct elf_link_hash_entry *h, void *data)
{
struct elf_info_failed *eif = (struct elf_info_failed *) data;
/* Ignore indirect symbols. These are added by the versioning code. */
if (h->root.type == bfd_link_hash_indirect)
return true;
/* Ignore this if we won't export it. */
if (!eif->info->export_dynamic && !h->dynamic)
return true;
if (h->dynindx == -1
&& (h->def_regular || h->ref_regular)
&& ! bfd_hide_sym_by_version (eif->info->version_info,
h->root.root.string))
{
if (! bfd_elf_link_record_dynamic_symbol (eif->info, h))
{
eif->failed = true;
return false;
}
}
return true;
}
/* Return the glibc version reference if VERSION_DEP is added to the
list of glibc version dependencies successfully. VERSION_DEP will
be put into the .gnu.version_r section. GLIBC_MINOR_BASE is the
pointer to the glibc minor base version. */
static Elf_Internal_Verneed *
elf_link_add_glibc_verneed (struct elf_find_verdep_info *rinfo,
Elf_Internal_Verneed *glibc_verref,
const char *version_dep,
int *glibc_minor_base)
{
Elf_Internal_Verneed *t;
Elf_Internal_Vernaux *a;
size_t amt;
int minor_version = -1;
if (glibc_verref != NULL)
{
t = glibc_verref;
for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
{
/* Return if VERSION_DEP dependency has been added. */
if (a->vna_nodename == version_dep
|| strcmp (a->vna_nodename, version_dep) == 0)
return t;
}
}
else
{
for (t = elf_tdata (rinfo->info->output_bfd)->verref;
t != NULL;
t = t->vn_nextref)
{
const char *soname = bfd_elf_get_dt_soname (t->vn_bfd);
if (soname != NULL && startswith (soname, "libc.so."))
break;
}
/* Skip the shared library if it isn't libc.so. */
if (t == NULL)
return t;
for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
{
/* Return if VERSION_DEP dependency has been added. */
if (a->vna_nodename == version_dep
|| strcmp (a->vna_nodename, version_dep) == 0)
return t;
/* Check if libc.so provides GLIBC_2.XX version. */
if (startswith (a->vna_nodename, "GLIBC_2."))
{
minor_version = strtol (a->vna_nodename + 8, NULL, 10);
if (minor_version < *glibc_minor_base)
*glibc_minor_base = minor_version;
}
}
/* Skip if it isn't linked against glibc. */
if (minor_version < 0)
return NULL;
}
/* Skip if 2.GLIBC_MINOR_BASE includes VERSION_DEP. */
if (startswith (version_dep, "GLIBC_2."))
{
minor_version = strtol (version_dep + 8, NULL, 10);
if (minor_version <= *glibc_minor_base)
return NULL;
}
amt = sizeof *a;
a = (Elf_Internal_Vernaux *) bfd_zalloc (rinfo->info->output_bfd, amt);
if (a == NULL)
{
rinfo->failed = true;
return NULL;
}
a->vna_nodename = version_dep;
a->vna_flags = 0;
a->vna_nextptr = t->vn_auxptr;
a->vna_other = rinfo->vers + 1;
++rinfo->vers;
t->vn_auxptr = a;
return t;
}
/* Add VERSION_DEP to the list of version dependencies when linked
against glibc. */
void
_bfd_elf_link_add_glibc_version_dependency
(struct elf_find_verdep_info *rinfo,
const char *version_dep[])
{
Elf_Internal_Verneed *t = NULL;
int glibc_minor_base = INT_MAX;
do
{
t = elf_link_add_glibc_verneed (rinfo, t, *version_dep,
&glibc_minor_base);
/* Return if there is no glibc version reference. */
if (t == NULL)
return;
version_dep++;
}
while (*version_dep != NULL);
}
/* Add GLIBC_ABI_DT_RELR to the list of version dependencies when
linked against glibc. */
void
_bfd_elf_link_add_dt_relr_dependency (struct elf_find_verdep_info *rinfo)
{
if (rinfo->info->enable_dt_relr)
{
const char *version[] =
{
"GLIBC_ABI_DT_RELR",
NULL
};
_bfd_elf_link_add_glibc_version_dependency (rinfo, version);
}
}
/* Look through the symbols which are defined in other shared
libraries and referenced here. Update the list of version
dependencies. This will be put into the .gnu.version_r section.
This function is called via elf_link_hash_traverse. */
static bool
_bfd_elf_link_find_version_dependencies (struct elf_link_hash_entry *h,
void *data)
{
struct elf_find_verdep_info *rinfo = (struct elf_find_verdep_info *) data;
Elf_Internal_Verneed *t;
Elf_Internal_Vernaux *a;
size_t amt;
/* We only care about symbols defined in shared objects with version
information. */
if (!h->def_dynamic
|| h->def_regular
|| h->dynindx == -1
|| h->verinfo.verdef == NULL
|| (elf_dyn_lib_class (h->verinfo.verdef->vd_bfd)
& (DYN_AS_NEEDED | DYN_DT_NEEDED | DYN_NO_NEEDED)))
return true;
/* See if we already know about this version. */
for (t = elf_tdata (rinfo->info->output_bfd)->verref;
t != NULL;
t = t->vn_nextref)
{
if (t->vn_bfd != h->verinfo.verdef->vd_bfd)
continue;
for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr)
if (a->vna_nodename == h->verinfo.verdef->vd_nodename)
return true;
break;
}
/* This is a new version. Add it to tree we are building. */
if (t == NULL)
{
amt = sizeof *t;
t = (Elf_Internal_Verneed *) bfd_zalloc (rinfo->info->output_bfd, amt);
if (t == NULL)
{
rinfo->failed = true;
return false;
}
t->vn_bfd = h->verinfo.verdef->vd_bfd;
t->vn_nextref = elf_tdata (rinfo->info->output_bfd)->verref;
elf_tdata (rinfo->info->output_bfd)->verref = t;
}
amt = sizeof *a;
a = (Elf_Internal_Vernaux *) bfd_zalloc (rinfo->info->output_bfd, amt);
if (a == NULL)
{
rinfo->failed = true;
return false;
}
/* Note that we are copying a string pointer here, and testing it
above. If bfd_elf_string_from_elf_section is ever changed to
discard the string data when low in memory, this will have to be
fixed. */
a->vna_nodename = h->verinfo.verdef->vd_nodename;
a->vna_flags = h->verinfo.verdef->vd_flags;
a->vna_nextptr = t->vn_auxptr;
h->verinfo.verdef->vd_exp_refno = rinfo->vers;
++rinfo->vers;
a->vna_other = h->verinfo.verdef->vd_exp_refno + 1;
t->vn_auxptr = a;
return true;
}
/* Return TRUE and set *HIDE to TRUE if the versioned symbol is
hidden. Set *T_P to NULL if there is no match. */
static bool
_bfd_elf_link_hide_versioned_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h,
const char *version_p,
struct bfd_elf_version_tree **t_p,
bool *hide)
{
struct bfd_elf_version_tree *t;
/* Look for the version. If we find it, it is no longer weak. */
for (t = info->version_info; t != NULL; t = t->next)
{
if (strcmp (t->name, version_p) == 0)
{
size_t len;
char *alc;
struct bfd_elf_version_expr *d;
len = version_p - h->root.root.string;
alc = (char *) bfd_malloc (len);
if (alc == NULL)
return false;
memcpy (alc, h->root.root.string, len - 1);
alc[len - 1] = '\0';
if (alc[len - 2] == ELF_VER_CHR)
alc[len - 2] = '\0';
h->verinfo.vertree = t;
t->used = true;
d = NULL;
if (t->globals.list != NULL)
d = (*t->match) (&t->globals, NULL, alc);
/* See if there is anything to force this symbol to
local scope. */
if (d == NULL && t->locals.list != NULL)
{
d = (*t->match) (&t->locals, NULL, alc);
if (d != NULL
&& h->dynindx != -1
&& ! info->export_dynamic)
*hide = true;
}
free (alc);
break;
}
}
*t_p = t;
return true;
}
/* Return TRUE if the symbol H is hidden by version script. */
bool
_bfd_elf_link_hide_sym_by_version (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
const char *p;
bool hide = false;
const struct elf_backend_data *bed
= get_elf_backend_data (info->output_bfd);
/* Version script only hides symbols defined in regular objects. */
if (!h->def_regular && !ELF_COMMON_DEF_P (h))
return true;
p = strchr (h->root.root.string, ELF_VER_CHR);
if (p != NULL && h->verinfo.vertree == NULL)
{
struct bfd_elf_version_tree *t;
++p;
if (*p == ELF_VER_CHR)
++p;
if (*p != '\0'
&& _bfd_elf_link_hide_versioned_symbol (info, h, p, &t, &hide)
&& hide)
{
if (hide)
(*bed->elf_backend_hide_symbol) (info, h, true);
return true;
}
}
/* If we don't have a version for this symbol, see if we can find
something. */
if (h->verinfo.vertree == NULL && info->version_info != NULL)
{
h->verinfo.vertree
= bfd_find_version_for_sym (info->version_info,
h->root.root.string, &hide);
if (h->verinfo.vertree != NULL && hide)
{
(*bed->elf_backend_hide_symbol) (info, h, true);
return true;
}
}
return false;
}
/* Figure out appropriate versions for all the symbols. We may not
have the version number script until we have read all of the input
files, so until that point we don't know which symbols should be
local. This function is called via elf_link_hash_traverse. */
static bool
_bfd_elf_link_assign_sym_version (struct elf_link_hash_entry *h, void *data)
{
struct elf_info_failed *sinfo;
struct bfd_link_info *info;
const struct elf_backend_data *bed;
struct elf_info_failed eif;
char *p;
bool hide;
sinfo = (struct elf_info_failed *) data;
info = sinfo->info;
/* Fix the symbol flags. */
eif.failed = false;
eif.info = info;
if (! _bfd_elf_fix_symbol_flags (h, &eif))
{
if (eif.failed)
sinfo->failed = true;
return false;
}
bed = get_elf_backend_data (info->output_bfd);
/* We only need version numbers for symbols defined in regular
objects. */
if (!h->def_regular && !ELF_COMMON_DEF_P (h))
{
/* Hide symbols defined in discarded input sections. */
if ((h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& discarded_section (h->root.u.def.section))
(*bed->elf_backend_hide_symbol) (info, h, true);
return true;
}
hide = false;
p = strchr (h->root.root.string, ELF_VER_CHR);
if (p != NULL && h->verinfo.vertree == NULL)
{
struct bfd_elf_version_tree *t;
++p;
if (*p == ELF_VER_CHR)
++p;
/* If there is no version string, we can just return out. */
if (*p == '\0')
return true;
if (!_bfd_elf_link_hide_versioned_symbol (info, h, p, &t, &hide))
{
sinfo->failed = true;
return false;
}
if (hide)
(*bed->elf_backend_hide_symbol) (info, h, true);
/* If we are building an application, we need to create a
version node for this version. */
if (t == NULL && bfd_link_executable (info))
{
struct bfd_elf_version_tree **pp;
int version_index;
/* If we aren't going to export this symbol, we don't need
to worry about it. */
if (h->dynindx == -1)
return true;
t = (struct bfd_elf_version_tree *) bfd_zalloc (info->output_bfd,
sizeof *t);
if (t == NULL)
{
sinfo->failed = true;
return false;
}
t->name = p;
t->name_indx = (unsigned int) -1;
t->used = true;
version_index = 1;
/* Don't count anonymous version tag. */
if (sinfo->info->version_info != NULL
&& sinfo->info->version_info->vernum == 0)
version_index = 0;
for (pp = &sinfo->info->version_info;
*pp != NULL;
pp = &(*pp)->next)
++version_index;
t->vernum = version_index;
*pp = t;
h->verinfo.vertree = t;
}
else if (t == NULL)
{
/* We could not find the version for a symbol when
generating a shared archive. Return an error. */
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: version node not found for symbol %s"),
info->output_bfd, h->root.root.string);
bfd_set_error (bfd_error_bad_value);
sinfo->failed = true;
return false;
}
}
/* If we don't have a version for this symbol, see if we can find
something. */
if (!hide
&& h->verinfo.vertree == NULL
&& sinfo->info->version_info != NULL)
{
h->verinfo.vertree
= bfd_find_version_for_sym (sinfo->info->version_info,
h->root.root.string, &hide);
if (h->verinfo.vertree != NULL && hide)
(*bed->elf_backend_hide_symbol) (info, h, true);
}
return true;
}
/* Read and swap the relocs from the section indicated by SHDR. This
may be either a REL or a RELA section. The relocations are
translated into RELA relocations and stored in INTERNAL_RELOCS,
which should have already been allocated to contain enough space.
The *EXTERNAL_RELOCS_P are a buffer where the external form of the
relocations should be stored. If *EXTERNAL_RELOCS_ADDR is NULL,
*EXTERNAL_RELOCS_ADDR and *EXTERNAL_RELOCS_SIZE returns the mmap
memory address and size. Otherwise, *EXTERNAL_RELOCS_ADDR is
unchanged and *EXTERNAL_RELOCS_SIZE returns 0.
Returns FALSE if something goes wrong. */
static bool
elf_link_read_relocs_from_section (bfd *abfd,
const asection *sec,
Elf_Internal_Shdr *shdr,
void **external_relocs_addr,
size_t *external_relocs_size,
Elf_Internal_Rela *internal_relocs)
{
const struct elf_backend_data *bed;
void (*swap_in) (bfd *, const bfd_byte *, Elf_Internal_Rela *);
const bfd_byte *erela;
const bfd_byte *erelaend;
Elf_Internal_Rela *irela;
Elf_Internal_Shdr *symtab_hdr;
size_t nsyms;
void *external_relocs = *external_relocs_addr;
/* Position ourselves at the start of the section. */
if (bfd_seek (abfd, shdr->sh_offset, SEEK_SET) != 0)
return false;
/* Read the relocations. */
*external_relocs_size = shdr->sh_size;
if (!_bfd_mmap_read_temporary (&external_relocs,
external_relocs_size,
external_relocs_addr, abfd, true))
return false;
symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
nsyms = NUM_SHDR_ENTRIES (symtab_hdr);
bed = get_elf_backend_data (abfd);
/* Convert the external relocations to the internal format. */
if (shdr->sh_entsize == bed->s->sizeof_rel)
swap_in = bed->s->swap_reloc_in;
else if (shdr->sh_entsize == bed->s->sizeof_rela)
swap_in = bed->s->swap_reloca_in;
else
{
bfd_set_error (bfd_error_wrong_format);
return false;
}
erela = (const bfd_byte *) external_relocs;
/* Setting erelaend like this and comparing with <= handles case of
a fuzzed object with sh_size not a multiple of sh_entsize. */
erelaend = erela + shdr->sh_size - shdr->sh_entsize;
irela = internal_relocs;
while (erela <= erelaend)
{
bfd_vma r_symndx;
(*swap_in) (abfd, erela, irela);
r_symndx = ELF32_R_SYM (irela->r_info);
if (bed->s->arch_size == 64)
r_symndx >>= 24;
if (nsyms > 0)
{
if ((size_t) r_symndx >= nsyms)
{
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: bad reloc symbol index (%#" PRIx64 " >= %#lx)"
" for offset %#" PRIx64 " in section `%pA'"),
abfd, (uint64_t) r_symndx, (unsigned long) nsyms,
(uint64_t) irela->r_offset, sec);
bfd_set_error (bfd_error_bad_value);
return false;
}
}
else if (r_symndx != STN_UNDEF)
{
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: non-zero symbol index (%#" PRIx64 ")"
" for offset %#" PRIx64 " in section `%pA'"
" when the object file has no symbol table"),
abfd, (uint64_t) r_symndx,
(uint64_t) irela->r_offset, sec);
bfd_set_error (bfd_error_bad_value);
return false;
}
irela += bed->s->int_rels_per_ext_rel;
erela += shdr->sh_entsize;
}
return true;
}
/* Read and swap the relocs for a section O. They may have been
cached. If the EXTERNAL_RELOCS and INTERNAL_RELOCS arguments are
not NULL, they are used as buffers to read into. They are known to
be large enough. If the INTERNAL_RELOCS relocs argument is NULL,
the return value is allocated using either malloc or bfd_alloc,
according to the KEEP_MEMORY argument. If O has two relocation
sections (both REL and RELA relocations), then the REL_HDR
relocations will appear first in INTERNAL_RELOCS, followed by the
RELA_HDR relocations. If INFO isn't NULL and KEEP_MEMORY is true,
update cache_size. */
Elf_Internal_Rela *
_bfd_elf_link_info_read_relocs (bfd *abfd,
struct bfd_link_info *info,
const asection *o,
void *external_relocs,
Elf_Internal_Rela *internal_relocs,
bool keep_memory)
{
void *alloc1 = NULL;
size_t alloc1_size;
Elf_Internal_Rela *alloc2 = NULL;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
struct bfd_elf_section_data *esdo = elf_section_data (o);
Elf_Internal_Rela *internal_rela_relocs;
if (esdo->relocs != NULL)
return esdo->relocs;
if (o->reloc_count == 0)
return NULL;
if (internal_relocs == NULL)
{
bfd_size_type size;
size = (bfd_size_type) o->reloc_count * sizeof (Elf_Internal_Rela);
if (keep_memory)
{
internal_relocs = alloc2 = (Elf_Internal_Rela *) bfd_alloc (abfd, size);
if (info)
info->cache_size += size;
}
else
internal_relocs = alloc2 = (Elf_Internal_Rela *) bfd_malloc (size);
if (internal_relocs == NULL)
return NULL;
}
alloc1 = external_relocs;
internal_rela_relocs = internal_relocs;
if (esdo->rel.hdr)
{
if (!elf_link_read_relocs_from_section (abfd, o, esdo->rel.hdr,
&alloc1, &alloc1_size,
internal_relocs))
goto error_return;
external_relocs = (((bfd_byte *) external_relocs)
+ esdo->rel.hdr->sh_size);
internal_rela_relocs += (NUM_SHDR_ENTRIES (esdo->rel.hdr)
* bed->s->int_rels_per_ext_rel);
}
if (esdo->rela.hdr
&& (!elf_link_read_relocs_from_section (abfd, o, esdo->rela.hdr,
&alloc1, &alloc1_size,
internal_rela_relocs)))
goto error_return;
/* Cache the results for next time, if we can. */
if (keep_memory)
esdo->relocs = internal_relocs;
_bfd_munmap_readonly_temporary (alloc1, alloc1_size);
/* Don't free alloc2, since if it was allocated we are passing it
back (under the name of internal_relocs). */
return internal_relocs;
error_return:
_bfd_munmap_readonly_temporary (alloc1, alloc1_size);
if (alloc2 != NULL)
{
if (keep_memory)
bfd_release (abfd, alloc2);
else
free (alloc2);
}
return NULL;
}
/* This is similar to _bfd_elf_link_info_read_relocs, except for that
NULL is passed to _bfd_elf_link_info_read_relocs for pointer to
struct bfd_link_info. */
Elf_Internal_Rela *
_bfd_elf_link_read_relocs (bfd *abfd,
const asection *o,
void *external_relocs,
Elf_Internal_Rela *internal_relocs,
bool keep_memory)
{
return _bfd_elf_link_info_read_relocs (abfd, NULL, o, external_relocs,
internal_relocs, keep_memory);
}
/* Compute the size of, and allocate space for, REL_HDR which is the
section header for a section containing relocations for O. */
static bool
_bfd_elf_link_size_reloc_section (bfd *abfd,
struct bfd_elf_section_reloc_data *reldata)
{
Elf_Internal_Shdr *rel_hdr = reldata->hdr;
/* That allows us to calculate the size of the section. */
rel_hdr->sh_size = rel_hdr->sh_entsize * reldata->count;
/* The contents field must last into write_object_contents, so we
allocate it with bfd_alloc rather than malloc. Also since we
cannot be sure that the contents will actually be filled in,
we zero the allocated space. */
rel_hdr->contents = (unsigned char *) bfd_zalloc (abfd, rel_hdr->sh_size);
if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0)
return false;
if (reldata->hashes == NULL && reldata->count)
{
struct elf_link_hash_entry **p;
p = ((struct elf_link_hash_entry **)
bfd_zmalloc (reldata->count * sizeof (*p)));
if (p == NULL)
return false;
reldata->hashes = p;
}
return true;
}
/* Copy the relocations indicated by the INTERNAL_RELOCS (which
originated from the section given by INPUT_REL_HDR) to the
OUTPUT_BFD. */
bool
_bfd_elf_link_output_relocs (bfd *output_bfd,
asection *input_section,
Elf_Internal_Shdr *input_rel_hdr,
Elf_Internal_Rela *internal_relocs,
struct elf_link_hash_entry **rel_hash)
{
Elf_Internal_Rela *irela;
Elf_Internal_Rela *irelaend;
bfd_byte *erel;
struct bfd_elf_section_reloc_data *output_reldata;
asection *output_section;
const struct elf_backend_data *bed;
void (*swap_out) (bfd *, const Elf_Internal_Rela *, bfd_byte *);
struct bfd_elf_section_data *esdo;
output_section = input_section->output_section;
bed = get_elf_backend_data (output_bfd);
esdo = elf_section_data (output_section);
if (esdo->rel.hdr && esdo->rel.hdr->sh_entsize == input_rel_hdr->sh_entsize)
{
output_reldata = &esdo->rel;
swap_out = bed->s->swap_reloc_out;
}
else if (esdo->rela.hdr
&& esdo->rela.hdr->sh_entsize == input_rel_hdr->sh_entsize)
{
output_reldata = &esdo->rela;
swap_out = bed->s->swap_reloca_out;
}
else
{
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: relocation size mismatch in %pB section %pA"),
output_bfd, input_section->owner, input_section);
bfd_set_error (bfd_error_wrong_format);
return false;
}
erel = output_reldata->hdr->contents;
erel += output_reldata->count * input_rel_hdr->sh_entsize;
irela = internal_relocs;
irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
* bed->s->int_rels_per_ext_rel);
while (irela < irelaend)
{
if (rel_hash && *rel_hash)
(*rel_hash)->has_reloc = 1;
(*swap_out) (output_bfd, irela, erel);
irela += bed->s->int_rels_per_ext_rel;
erel += input_rel_hdr->sh_entsize;
if (rel_hash)
rel_hash++;
}
/* Bump the counter, so that we know where to add the next set of
relocations. */
output_reldata->count += NUM_SHDR_ENTRIES (input_rel_hdr);
return true;
}
/* Make weak undefined symbols in PIE dynamic. */
bool
_bfd_elf_link_hash_fixup_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
if (bfd_link_pie (info)
&& h->dynindx == -1
&& h->root.type == bfd_link_hash_undefweak)
return bfd_elf_link_record_dynamic_symbol (info, h);
return true;
}
/* Fix up the flags for a symbol. This handles various cases which
can only be fixed after all the input files are seen. This is
currently called by both adjust_dynamic_symbol and
assign_sym_version, which is unnecessary but perhaps more robust in
the face of future changes. */
static bool
_bfd_elf_fix_symbol_flags (struct elf_link_hash_entry *h,
struct elf_info_failed *eif)
{
const struct elf_backend_data *bed;
/* If this symbol was mentioned in a non-ELF file, try to set
DEF_REGULAR and REF_REGULAR correctly. This is the only way to
permit a non-ELF file to correctly refer to a symbol defined in
an ELF dynamic object. */
if (h->non_elf)
{
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_defined
&& h->root.type != bfd_link_hash_defweak)
{
h->ref_regular = 1;
h->ref_regular_nonweak = 1;
}
else
{
if (h->root.u.def.section->owner != NULL
&& (bfd_get_flavour (h->root.u.def.section->owner)
== bfd_target_elf_flavour))
{
h->ref_regular = 1;
h->ref_regular_nonweak = 1;
}
else
h->def_regular = 1;
}
if (h->dynindx == -1
&& (h->def_dynamic
|| h->ref_dynamic))
{
if (! bfd_elf_link_record_dynamic_symbol (eif->info, h))
{
eif->failed = true;
return false;
}
}
}
else
{
/* Unfortunately, NON_ELF is only correct if the symbol
was first seen in a non-ELF file. Fortunately, if the symbol
was first seen in an ELF file, we're probably OK unless the
symbol was defined in a non-ELF file. Catch that case here.
FIXME: We're still in trouble if the symbol was first seen in
a dynamic object, and then later in a non-ELF regular object. */
if ((h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& !h->def_regular