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gnu / binutils-gdb / refs/tags/ezannoni_pie-20040323-branchpoint / . / bfd / elflink.c
blob: 39bf46f769e384c541297df4db345ac4c8b99029 [file] [log] [blame]
/* ELF linking support for BFD.
Copyright 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#include "bfd.h"
#include "sysdep.h"
#include "bfdlink.h"
#include "libbfd.h"
#define ARCH_SIZE 0
#include "elf-bfd.h"
bfd_boolean
_bfd_elf_create_got_section (bfd *abfd, struct bfd_link_info *info)
{
flagword flags;
asection *s;
struct elf_link_hash_entry *h;
struct bfd_link_hash_entry *bh;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
int ptralign;
/* This function may be called more than once. */
s = bfd_get_section_by_name (abfd, ".got");
if (s != NULL && (s->flags & SEC_LINKER_CREATED) != 0)
return TRUE;
switch (bed->s->arch_size)
{
case 32:
ptralign = 2;
break;
case 64:
ptralign = 3;
break;
default:
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY
| SEC_LINKER_CREATED);
s = bfd_make_section (abfd, ".got");
if (s == NULL
|| !bfd_set_section_flags (abfd, s, flags)
|| !bfd_set_section_alignment (abfd, s, ptralign))
return FALSE;
if (bed->want_got_plt)
{
s = bfd_make_section (abfd, ".got.plt");
if (s == NULL
|| !bfd_set_section_flags (abfd, s, flags)
|| !bfd_set_section_alignment (abfd, s, ptralign))
return FALSE;
}
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. */
bh = NULL;
if (!(_bfd_generic_link_add_one_symbol
(info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s,
bed->got_symbol_offset, NULL, FALSE, bed->collect, &bh)))
return FALSE;
h = (struct elf_link_hash_entry *) bh;
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
h->type = STT_OBJECT;
if (! info->executable
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
elf_hash_table (info)->hgot = h;
}
/* The first bit of the global offset table is the header. */
s->_raw_size += bed->got_header_size + bed->got_symbol_offset;
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. */
bfd_boolean
_bfd_elf_link_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info)
{
flagword flags;
register asection *s;
struct elf_link_hash_entry *h;
struct bfd_link_hash_entry *bh;
const struct elf_backend_data *bed;
if (! is_elf_hash_table (info->hash))
return FALSE;
if (elf_hash_table (info)->dynamic_sections_created)
return TRUE;
/* Make sure that all dynamic sections use the same input BFD. */
if (elf_hash_table (info)->dynobj == NULL)
elf_hash_table (info)->dynobj = abfd;
else
abfd = elf_hash_table (info)->dynobj;
/* Note that we set the SEC_IN_MEMORY flag for all of these
sections. */
flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS
| SEC_IN_MEMORY | SEC_LINKER_CREATED);
/* A dynamically linked executable has a .interp section, but a
shared library does not. */
if (info->executable)
{
s = bfd_make_section (abfd, ".interp");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
return FALSE;
}
if (! info->traditional_format)
{
s = bfd_make_section (abfd, ".eh_frame_hdr");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, 2))
return FALSE;
elf_hash_table (info)->eh_info.hdr_sec = s;
}
bed = get_elf_backend_data (abfd);
/* Create sections to hold version informations. These are removed
if they are not needed. */
s = bfd_make_section (abfd, ".gnu.version_d");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
s = bfd_make_section (abfd, ".gnu.version");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, 1))
return FALSE;
s = bfd_make_section (abfd, ".gnu.version_r");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
s = bfd_make_section (abfd, ".dynsym");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
s = bfd_make_section (abfd, ".dynstr");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
return FALSE;
/* Create a strtab to hold the dynamic symbol names. */
if (elf_hash_table (info)->dynstr == NULL)
{
elf_hash_table (info)->dynstr = _bfd_elf_strtab_init ();
if (elf_hash_table (info)->dynstr == NULL)
return FALSE;
}
s = bfd_make_section (abfd, ".dynamic");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
/* The special symbol _DYNAMIC is always set to the start of the
.dynamic section. This call occurs before we have processed the
symbols for any dynamic object, so we don't have to worry about
overriding a dynamic definition. 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. */
bh = NULL;
if (! (_bfd_generic_link_add_one_symbol
(info, abfd, "_DYNAMIC", BSF_GLOBAL, s, 0, NULL, FALSE,
get_elf_backend_data (abfd)->collect, &bh)))
return FALSE;
h = (struct elf_link_hash_entry *) bh;
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
h->type = STT_OBJECT;
if (! info->executable
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
s = bfd_make_section (abfd, ".hash");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
elf_section_data (s)->this_hdr.sh_entsize = bed->s->sizeof_hash_entry;
/* 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) (abfd, info))
return FALSE;
elf_hash_table (info)->dynamic_sections_created = TRUE;
return TRUE;
}
/* Create dynamic sections when linking against a dynamic object. */
bfd_boolean
_bfd_elf_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info)
{
flagword flags, pltflags;
asection *s;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
/* We need to create .plt, .rel[a].plt, .got, .got.plt, .dynbss, and
.rel[a].bss sections. */
flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY
| SEC_LINKER_CREATED);
pltflags = flags;
pltflags |= SEC_CODE;
if (bed->plt_not_loaded)
pltflags &= ~ (SEC_CODE | SEC_LOAD | SEC_HAS_CONTENTS);
if (bed->plt_readonly)
pltflags |= SEC_READONLY;
s = bfd_make_section (abfd, ".plt");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, pltflags)
|| ! bfd_set_section_alignment (abfd, s, bed->plt_alignment))
return FALSE;
if (bed->want_plt_sym)
{
/* Define the symbol _PROCEDURE_LINKAGE_TABLE_ at the start of the
.plt section. */
struct elf_link_hash_entry *h;
struct bfd_link_hash_entry *bh = NULL;
if (! (_bfd_generic_link_add_one_symbol
(info, abfd, "_PROCEDURE_LINKAGE_TABLE_", BSF_GLOBAL, s, 0, NULL,
FALSE, get_elf_backend_data (abfd)->collect, &bh)))
return FALSE;
h = (struct elf_link_hash_entry *) bh;
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
h->type = STT_OBJECT;
if (! info->executable
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
}
s = bfd_make_section (abfd,
bed->default_use_rela_p ? ".rela.plt" : ".rel.plt");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
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 (abfd, ".dynbss");
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, SEC_ALLOC | SEC_LINKER_CREATED))
return FALSE;
/* 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 (! info->shared)
{
s = bfd_make_section (abfd,
(bed->default_use_rela_p
? ".rela.bss" : ".rel.bss"));
if (s == NULL
|| ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
}
}
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. */
bfd_boolean
_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;
bfd_size_type indx;
/* 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->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL;
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;
}
/* 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)
/* We know that the p points into writable memory. In fact,
there are only a few symbols that have read-only names, being
those like _GLOBAL_OFFSET_TABLE_ that are created specially
by the backends. Most symbols will have names pointing into
an ELF string table read from a file, or to objalloc memory. */
*p = 0;
indx = _bfd_elf_strtab_add (dynstr, name, p != NULL);
if (p != NULL)
*p = ELF_VER_CHR;
if (indx == (bfd_size_type) -1)
return FALSE;
h->dynstr_index = indx;
}
return TRUE;
}
/* Record an assignment to a symbol made by a linker script. We need
this in case some dynamic object refers to this symbol. */
bfd_boolean
bfd_elf_record_link_assignment (bfd *output_bfd ATTRIBUTE_UNUSED,
struct bfd_link_info *info,
const char *name,
bfd_boolean provide)
{
struct elf_link_hash_entry *h;
if (!is_elf_hash_table (info->hash))
return TRUE;
h = elf_link_hash_lookup (elf_hash_table (info), name, TRUE, TRUE, FALSE);
if (h == NULL)
return FALSE;
/* 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. */
if (h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_undefined)
h->root.type = bfd_link_hash_new;
if (h->root.type == bfd_link_hash_new)
h->elf_link_hash_flags &= ~ELF_LINK_NON_ELF;
/* 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->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
h->root.type = bfd_link_hash_undefined;
/* If this symbol is not being provided by the linker script, and it 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 (!provide
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
h->verinfo.verdef = NULL;
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
if (((h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC
| ELF_LINK_HASH_REF_DYNAMIC)) != 0
|| info->shared)
&& 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->weakdef != NULL
&& h->weakdef->dynindx == -1)
{
if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef))
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
elf_link_record_local_dynamic_symbol (struct bfd_link_info *info,
bfd *input_bfd,
long input_indx)
{
bfd_size_type amt;
struct elf_link_local_dynamic_entry *entry;
struct elf_link_hash_table *eht;
struct elf_strtab_hash *dynstr;
unsigned long 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 = 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
|| entry->isym.st_shndx > SHN_HIRESERVE))
{
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 == (unsigned long) -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 bfd_boolean
elf_link_renumber_hash_table_dynsyms (struct elf_link_hash_entry *h,
void *data)
{
size_t *count = data;
if (h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
if (h->dynindx != -1)
h->dynindx = ++(*count);
return TRUE;
}
/* Assign dynsym indices. In a shared library we generate a section
symbol for each output section, which come first. Next come all of
the back-end allocated local dynamic syms, followed by the rest of
the global symbols. */
unsigned long
_bfd_elf_link_renumber_dynsyms (bfd *output_bfd, struct bfd_link_info *info)
{
unsigned long dynsymcount = 0;
if (info->shared)
{
asection *p;
for (p = output_bfd->sections; p ; p = p->next)
if ((p->flags & SEC_EXCLUDE) == 0)
elf_section_data (p)->dynindx = ++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_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. Unless there weren't any
symbols, which means we'll have no table at all. */
if (dynsymcount != 0)
++dynsymcount;
return elf_hash_table (info)->dynsymcount = dynsymcount;
}
/* This function is called when we want to define a new 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
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. */
bfd_boolean
_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_boolean *skip,
bfd_boolean *override,
bfd_boolean *type_change_ok,
bfd_boolean *size_change_ok)
{
asection *sec;
struct elf_link_hash_entry *h;
struct elf_link_hash_entry *flip;
int bind;
bfd *oldbfd;
bfd_boolean newdyn, olddyn, olddef, newdef, newdyncommon, olddyncommon;
bfd_boolean newweak, oldweak;
*skip = FALSE;
*override = FALSE;
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;
/* This code is for coping with dynamic objects, and is only useful
if we are doing an ELF link. */
if (info->hash->creator != abfd->xvec)
return TRUE;
/* For merging, we only care about real symbols. */
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 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->elf_link_hash_flags &=~ ELF_LINK_NON_ELF;
return TRUE;
}
/* OLDBFD is a BFD associated with the existing symbol. */
switch (h->root.type)
{
default:
oldbfd = NULL;
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;
break;
case bfd_link_hash_common:
oldbfd = h->root.u.c.p->section->owner;
break;
}
/* 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
&& ((abfd->flags & DYNAMIC) == 0
|| (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0))
return TRUE;
/* NEWDYN and OLDDYN indicate whether the new or old symbol,
respectively, is from a dynamic object. */
if ((abfd->flags & DYNAMIC) != 0)
newdyn = TRUE;
else
newdyn = FALSE;
if (oldbfd != NULL)
olddyn = (oldbfd->flags & DYNAMIC) != 0;
else
{
asection *hsec;
/* This code handles the special SHN_MIPS_{TEXT,DATA} section
indices used by MIPS ELF. */
switch (h->root.type)
{
default:
hsec = NULL;
break;
case bfd_link_hash_defined:
case bfd_link_hash_defweak:
hsec = h->root.u.def.section;
break;
case bfd_link_hash_common:
hsec = h->root.u.c.p->section;
break;
}
if (hsec == NULL)
olddyn = FALSE;
else
olddyn = (hsec->symbol->flags & BSF_DYNAMIC) != 0;
}
/* NEWDEF and OLDDEF indicate whether the new or old symbol,
respectively, appear to be a definition rather than reference. */
if (bfd_is_und_section (sec) || bfd_is_com_section (sec))
newdef = FALSE;
else
newdef = TRUE;
if (h->root.type == bfd_link_hash_undefined
|| h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_common)
olddef = FALSE;
else
olddef = TRUE;
/* We need to remember if a symbol has a definition in a dynamic
object or is weak in all dynamic objects. Internal and hidden
visibility will make it unavailable to dynamic objects. */
if (newdyn && (h->elf_link_hash_flags & ELF_LINK_DYNAMIC_DEF) == 0)
{
if (!bfd_is_und_section (sec))
h->elf_link_hash_flags |= ELF_LINK_DYNAMIC_DEF;
else
{
/* Check if this symbol is weak in all dynamic objects. If it
is the first time we see it in a dynamic object, we mark
if it is weak. Otherwise, we clear it. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) == 0)
{
if (bind == STB_WEAK)
h->elf_link_hash_flags |= ELF_LINK_DYNAMIC_WEAK;
}
else if (bind != STB_WEAK)
h->elf_link_hash_flags &= ~ELF_LINK_DYNAMIC_WEAK;
}
}
/* 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->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC;
/* 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->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0)
{
/* 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 ((*sym_hash)->root.type == bfd_link_hash_indirect)
h = *sym_hash;
if ((h->root.und_next || info->hash->undefs_tail == &h->root)
&& bfd_is_und_section (sec))
{
/* If the new symbol is undefined and the old symbol was
also undefined before, we need to make sure
_bfd_generic_link_add_one_symbol doesn't mess
up the linker hash table undefs list. Since the old
definition came from a dynamic object, it is still on the
undefs list. */
h->root.type = bfd_link_hash_undefined;
/* FIXME: What if the new symbol is weak undefined? */
h->root.u.undef.abfd = abfd;
}
else
{
h->root.type = bfd_link_hash_new;
h->root.u.undef.abfd = NULL;
}
if (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC)
{
h->elf_link_hash_flags &= ~ELF_LINK_HASH_DEF_DYNAMIC;
h->elf_link_hash_flags |= (ELF_LINK_HASH_REF_DYNAMIC
| ELF_LINK_DYNAMIC_DEF);
}
/* FIXME: Should we check type and size for protected symbol? */
h->size = 0;
h->type = 0;
return TRUE;
}
/* 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 a new weak symbol 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 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. */
if (!newdyn && olddyn)
newweak = FALSE;
if (newdyn)
oldweak = FALSE;
/* 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
&& ELF_ST_TYPE (sym->st_info) != STT_FUNC)
newdyncommon = TRUE;
else
newdyncommon = FALSE;
if (olddyn
&& olddef
&& h->root.type == bfd_link_hash_defined
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
&& (h->root.u.def.section->flags & SEC_ALLOC) != 0
&& (h->root.u.def.section->flags & SEC_LOAD) == 0
&& h->size > 0
&& h->type != STT_FUNC)
olddyncommon = TRUE;
else
olddyncommon = FALSE;
/* 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. */
if (! ((*info->callbacks->multiple_common)
(info, h->root.root.string, oldbfd, bfd_link_hash_common,
h->size, abfd, bfd_link_hash_common, sym->st_size)))
return FALSE;
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
|| ELF_ST_TYPE (sym->st_info) == STT_FUNC))))
{
*override = TRUE;
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 will do
the right thing. */
if (newdyncommon
&& h->root.type == bfd_link_hash_common)
{
*override = TRUE;
newdef = FALSE;
newdyncommon = FALSE;
*pvalue = sym->st_size;
*psec = sec = bfd_com_section_ptr;
*size_change_ok = TRUE;
}
/* 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
|| h->type == STT_FUNC)))
&& olddyn
&& olddef
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0)
{
/* 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))
*type_change_ok = TRUE;
if ((*sym_hash)->root.type == bfd_link_hash_indirect)
flip = *sym_hash;
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. */
if (! ((*info->callbacks->multiple_common)
(info, h->root.root.string, oldbfd, bfd_link_hash_common,
h->size, abfd, bfd_link_hash_common, sym->st_size)))
return FALSE;
/* 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;
/* FIXME: We no longer know the alignment required by the symbol
in the dynamic object, so we just wind up using the one from
the regular object. */
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 ((*sym_hash)->root.type == bfd_link_hash_indirect)
flip = *sym_hash;
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. */
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
flip->root.type = h->root.type;
h->root.type = bfd_link_hash_indirect;
h->root.u.i.link = (struct bfd_link_hash_entry *) flip;
(*bed->elf_backend_copy_indirect_symbol) (bed, flip, h);
flip->root.u.undef.abfd = h->root.u.undef.abfd;
if (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC)
{
h->elf_link_hash_flags &= ~ELF_LINK_HASH_DEF_DYNAMIC;
flip->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC;
}
}
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, PSEC, VALUE, and OVERRIDE. We
set DYNSYM if the new indirect symbol is dynamic. */
bfd_boolean
_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 **psec,
bfd_vma *value,
bfd_boolean *dynsym,
bfd_boolean override)
{
bfd_boolean type_change_ok;
bfd_boolean size_change_ok;
bfd_boolean skip;
char *shortname;
struct elf_link_hash_entry *hi;
struct bfd_link_hash_entry *bh;
const struct elf_backend_data *bed;
bfd_boolean collect;
bfd_boolean dynamic;
char *p;
size_t len, shortlen;
asection *sec;
/* 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 (p == NULL || p[1] != ELF_VER_CHR)
return TRUE;
if (override)
{
/* We are overridden by an old definition. We need to check if we
need to create the indirect symbol from the default name. */
hi = elf_link_hash_lookup (elf_hash_table (info), name, TRUE,
FALSE, FALSE);
BFD_ASSERT (hi != NULL);
if (hi == h)
return TRUE;
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;
if (hi == h)
return TRUE;
}
}
bed = get_elf_backend_data (abfd);
collect = bed->collect;
dynamic = (abfd->flags & DYNAMIC) != 0;
shortlen = p - name;
shortname = 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;
sec = *psec;
if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &sec, value,
&hi, &skip, &override, &type_change_ok,
&size_change_ok))
return FALSE;
if (skip)
goto nondefault;
if (! override)
{
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;
}
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->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC)
{
h->elf_link_hash_flags &=~ ELF_LINK_HASH_DEF_DYNAMIC;
hi->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC;
if (hi->elf_link_hash_flags
& (ELF_LINK_HASH_REF_REGULAR
| ELF_LINK_HASH_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;
}
/* 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) (bed, ht, hi);
/* See if the new flags lead us to realize that the symbol must
be dynamic. */
if (! *dynsym)
{
if (! dynamic)
{
if (info->shared
|| ((hi->elf_link_hash_flags
& ELF_LINK_HASH_REF_DYNAMIC) != 0))
*dynsym = TRUE;
}
else
{
if ((hi->elf_link_hash_flags
& ELF_LINK_HASH_REF_REGULAR) != 0)
*dynsym = TRUE;
}
}
}
/* We also need to define an indirection from the nondefault version
of the symbol. */
nondefault:
len = strlen (name);
shortname = 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;
sec = *psec;
if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &sec, value,
&hi, &skip, &override, &type_change_ok,
&size_change_ok))
return FALSE;
if (skip)
return TRUE;
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)
(_("%s: warning: unexpected redefinition of indirect versioned symbol `%s'"),
bfd_archive_filename (abfd), shortname);
}
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) (bed, h, hi);
/* See if the new flags lead us to realize that the symbol
must be dynamic. */
if (! *dynsym)
{
if (! dynamic)
{
if (info->shared
|| ((hi->elf_link_hash_flags
& ELF_LINK_HASH_REF_DYNAMIC) != 0))
*dynsym = TRUE;
}
else
{
if ((hi->elf_link_hash_flags
& ELF_LINK_HASH_REF_REGULAR) != 0)
*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. */
bfd_boolean
_bfd_elf_export_symbol (struct elf_link_hash_entry *h, void *data)
{
struct elf_info_failed *eif = data;
/* Ignore indirect symbols. These are added by the versioning code. */
if (h->root.type == bfd_link_hash_indirect)
return TRUE;
if (h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
if (h->dynindx == -1
&& (h->elf_link_hash_flags
& (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0)
{
struct bfd_elf_version_tree *t;
struct bfd_elf_version_expr *d;
for (t = eif->verdefs; t != NULL; t = t->next)
{
if (t->globals.list != NULL)
{
d = (*t->match) (&t->globals, NULL, h->root.root.string);
if (d != NULL)
goto doit;
}
if (t->locals.list != NULL)
{
d = (*t->match) (&t->locals, NULL, h->root.root.string);
if (d != NULL)
return TRUE;
}
}
if (!eif->verdefs)
{
doit:
if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h))
{
eif->failed = TRUE;
return FALSE;
}
}
}
return TRUE;
}
/* 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. */
bfd_boolean
_bfd_elf_link_find_version_dependencies (struct elf_link_hash_entry *h,
void *data)
{
struct elf_find_verdep_info *rinfo = data;
Elf_Internal_Verneed *t;
Elf_Internal_Vernaux *a;
bfd_size_type amt;
if (h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
/* We only care about symbols defined in shared objects with version
information. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
|| (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
|| h->dynindx == -1
|| h->verinfo.verdef == NULL)
return TRUE;
/* See if we already know about this version. */
for (t = elf_tdata (rinfo->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 = bfd_zalloc (rinfo->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->output_bfd)->verref;
elf_tdata (rinfo->output_bfd)->verref = t;
}
amt = sizeof *a;
a = bfd_zalloc (rinfo->output_bfd, amt);
/* 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;
}
/* 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. */
bfd_boolean
_bfd_elf_link_assign_sym_version (struct elf_link_hash_entry *h, void *data)
{
struct elf_assign_sym_version_info *sinfo;
struct bfd_link_info *info;
const struct elf_backend_data *bed;
struct elf_info_failed eif;
char *p;
bfd_size_type amt;
sinfo = data;
info = sinfo->info;
if (h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
/* 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;
}
/* We only need version numbers for symbols defined in regular
objects. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
return TRUE;
bed = get_elf_backend_data (sinfo->output_bfd);
p = strchr (h->root.root.string, ELF_VER_CHR);
if (p != NULL && h->verinfo.vertree == NULL)
{
struct bfd_elf_version_tree *t;
bfd_boolean hidden;
hidden = TRUE;
/* There are two consecutive ELF_VER_CHR characters if this is
not a hidden symbol. */
++p;
if (*p == ELF_VER_CHR)
{
hidden = FALSE;
++p;
}
/* If there is no version string, we can just return out. */
if (*p == '\0')
{
if (hidden)
h->elf_link_hash_flags |= ELF_LINK_HIDDEN;
return TRUE;
}
/* Look for the version. If we find it, it is no longer weak. */
for (t = sinfo->verdefs; t != NULL; t = t->next)
{
if (strcmp (t->name, p) == 0)
{
size_t len;
char *alc;
struct bfd_elf_version_expr *d;
len = p - h->root.root.string;
alc = 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->shared
&& ! info->export_dynamic)
(*bed->elf_backend_hide_symbol) (info, h, TRUE);
}
free (alc);
break;
}
}
/* If we are building an application, we need to create a
version node for this version. */
if (t == NULL && info->executable)
{
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;
amt = sizeof *t;
t = bfd_zalloc (sinfo->output_bfd, amt);
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->verdefs != NULL && sinfo->verdefs->vernum == 0)
version_index = 0;
for (pp = &sinfo->verdefs; *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)
(_("%s: undefined versioned symbol name %s"),
bfd_get_filename (sinfo->output_bfd), h->root.root.string);
bfd_set_error (bfd_error_bad_value);
sinfo->failed = TRUE;
return FALSE;
}
if (hidden)
h->elf_link_hash_flags |= ELF_LINK_HIDDEN;
}
/* If we don't have a version for this symbol, see if we can find
something. */
if (h->verinfo.vertree == NULL && sinfo->verdefs != NULL)
{
struct bfd_elf_version_tree *t;
struct bfd_elf_version_tree *local_ver;
struct bfd_elf_version_expr *d;
/* See if can find what version this symbol is in. If the
symbol is supposed to be local, then don't actually register
it. */
local_ver = NULL;
for (t = sinfo->verdefs; t != NULL; t = t->next)
{
if (t->globals.list != NULL)
{
bfd_boolean matched;
matched = FALSE;
d = NULL;
while ((d = (*t->match) (&t->globals, d,
h->root.root.string)) != NULL)
if (d->symver)
matched = TRUE;
else
{
/* There is a version without definition. Make
the symbol the default definition for this
version. */
h->verinfo.vertree = t;
local_ver = NULL;
d->script = 1;
break;
}
if (d != NULL)
break;
else if (matched)
/* There is no undefined version for this symbol. Hide the
default one. */
(*bed->elf_backend_hide_symbol) (info, h, TRUE);
}
if (t->locals.list != NULL)
{
d = NULL;
while ((d = (*t->match) (&t->locals, d,
h->root.root.string)) != NULL)
{
local_ver = t;
/* If the match is "*", keep looking for a more
explicit, perhaps even global, match.
XXX: Shouldn't this be !d->wildcard instead? */
if (d->pattern[0] != '*' || d->pattern[1] != '\0')
break;
}
if (d != NULL)
break;
}
}
if (local_ver != NULL)
{
h->verinfo.vertree = local_ver;
if (h->dynindx != -1
&& info->shared
&& ! info->export_dynamic)
{
(*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 are a buffer where the external form of the
relocations should be stored.
Returns FALSE if something goes wrong. */
static bfd_boolean
elf_link_read_relocs_from_section (bfd *abfd,
asection *sec,
Elf_Internal_Shdr *shdr,
void *external_relocs,
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;
/* Position ourselves at the start of the section. */
if (bfd_seek (abfd, shdr->sh_offset, SEEK_SET) != 0)
return FALSE;
/* Read the relocations. */
if (bfd_bread (external_relocs, shdr->sh_size, abfd) != shdr->sh_size)
return FALSE;
symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
nsyms = symtab_hdr->sh_size / symtab_hdr->sh_entsize;
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 = external_relocs;
erelaend = erela + shdr->sh_size;
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 ((size_t) r_symndx >= nsyms)
{
(*_bfd_error_handler)
(_("%s: bad reloc symbol index (0x%lx >= 0x%lx) for offset 0x%lx in section `%s'"),
bfd_archive_filename (abfd), (unsigned long) r_symndx,
(unsigned long) nsyms, irela->r_offset, sec->name);
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
REL_HDR2 relocations. */
Elf_Internal_Rela *
_bfd_elf_link_read_relocs (bfd *abfd,
asection *o,
void *external_relocs,
Elf_Internal_Rela *internal_relocs,
bfd_boolean keep_memory)
{
Elf_Internal_Shdr *rel_hdr;
void *alloc1 = NULL;
Elf_Internal_Rela *alloc2 = NULL;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
if (elf_section_data (o)->relocs != NULL)
return elf_section_data (o)->relocs;
if (o->reloc_count == 0)
return NULL;
rel_hdr = &elf_section_data (o)->rel_hdr;
if (internal_relocs == NULL)
{
bfd_size_type size;
size = o->reloc_count;
size *= bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rela);
if (keep_memory)
internal_relocs = bfd_alloc (abfd, size);
else
internal_relocs = alloc2 = bfd_malloc (size);
if (internal_relocs == NULL)
goto error_return;
}
if (external_relocs == NULL)
{
bfd_size_type size = rel_hdr->sh_size;
if (elf_section_data (o)->rel_hdr2)
size += elf_section_data (o)->rel_hdr2->sh_size;
alloc1 = bfd_malloc (size);
if (alloc1 == NULL)
goto error_return;
external_relocs = alloc1;
}
if (!elf_link_read_relocs_from_section (abfd, o, rel_hdr,
external_relocs,
internal_relocs))
goto error_return;
if (elf_section_data (o)->rel_hdr2
&& (!elf_link_read_relocs_from_section
(abfd, o,
elf_section_data (o)->rel_hdr2,
((bfd_byte *) external_relocs) + rel_hdr->sh_size,
internal_relocs + (NUM_SHDR_ENTRIES (rel_hdr)
* bed->s->int_rels_per_ext_rel))))
goto error_return;
/* Cache the results for next time, if we can. */
if (keep_memory)
elf_section_data (o)->relocs = internal_relocs;
if (alloc1 != NULL)
free (alloc1);
/* 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:
if (alloc1 != NULL)
free (alloc1);
if (alloc2 != NULL)
free (alloc2);
return NULL;
}
/* Compute the size of, and allocate space for, REL_HDR which is the
section header for a section containing relocations for O. */
bfd_boolean
_bfd_elf_link_size_reloc_section (bfd *abfd,
Elf_Internal_Shdr *rel_hdr,
asection *o)
{
bfd_size_type reloc_count;
bfd_size_type num_rel_hashes;
/* Figure out how many relocations there will be. */
if (rel_hdr == &elf_section_data (o)->rel_hdr)
reloc_count = elf_section_data (o)->rel_count;
else
reloc_count = elf_section_data (o)->rel_count2;
num_rel_hashes = o->reloc_count;
if (num_rel_hashes < reloc_count)
num_rel_hashes = reloc_count;
/* That allows us to calculate the size of the section. */
rel_hdr->sh_size = rel_hdr->sh_entsize * reloc_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 = bfd_zalloc (abfd, rel_hdr->sh_size);
if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0)
return FALSE;
/* We only allocate one set of hash entries, so we only do it the
first time we are called. */
if (elf_section_data (o)->rel_hashes == NULL
&& num_rel_hashes)
{
struct elf_link_hash_entry **p;
p = bfd_zmalloc (num_rel_hashes * sizeof (struct elf_link_hash_entry *));
if (p == NULL)
return FALSE;
elf_section_data (o)->rel_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. */
bfd_boolean
_bfd_elf_link_output_relocs (bfd *output_bfd,
asection *input_section,
Elf_Internal_Shdr *input_rel_hdr,
Elf_Internal_Rela *internal_relocs)
{
Elf_Internal_Rela *irela;
Elf_Internal_Rela *irelaend;
bfd_byte *erel;
Elf_Internal_Shdr *output_rel_hdr;
asection *output_section;
unsigned int *rel_countp = NULL;
const struct elf_backend_data *bed;
void (*swap_out) (bfd *, const Elf_Internal_Rela *, bfd_byte *);
output_section = input_section->output_section;
output_rel_hdr = NULL;
if (elf_section_data (output_section)->rel_hdr.sh_entsize
== input_rel_hdr->sh_entsize)
{
output_rel_hdr = &elf_section_data (output_section)->rel_hdr;
rel_countp = &elf_section_data (output_section)->rel_count;
}
else if (elf_section_data (output_section)->rel_hdr2
&& (elf_section_data (output_section)->rel_hdr2->sh_entsize
== input_rel_hdr->sh_entsize))
{
output_rel_hdr = elf_section_data (output_section)->rel_hdr2;
rel_countp = &elf_section_data (output_section)->rel_count2;
}
else
{
(*_bfd_error_handler)
(_("%s: relocation size mismatch in %s section %s"),
bfd_get_filename (output_bfd),
bfd_archive_filename (input_section->owner),
input_section->name);
bfd_set_error (bfd_error_wrong_object_format);
return FALSE;
}
bed = get_elf_backend_data (output_bfd);
if (input_rel_hdr->sh_entsize == bed->s->sizeof_rel)
swap_out = bed->s->swap_reloc_out;
else if (input_rel_hdr->sh_entsize == bed->s->sizeof_rela)
swap_out = bed->s->swap_reloca_out;
else
abort ();
erel = output_rel_hdr->contents;
erel += *rel_countp * 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)
{
(*swap_out) (output_bfd, irela, erel);
irela += bed->s->int_rels_per_ext_rel;
erel += input_rel_hdr->sh_entsize;
}
/* Bump the counter, so that we know where to add the next set of
relocations. */
*rel_countp += NUM_SHDR_ENTRIES (input_rel_hdr);
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. */
bfd_boolean
_bfd_elf_fix_symbol_flags (struct elf_link_hash_entry *h,
struct elf_info_failed *eif)
{
/* 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->elf_link_hash_flags & ELF_LINK_NON_ELF) != 0)
{
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->elf_link_hash_flags |= (ELF_LINK_HASH_REF_REGULAR
| ELF_LINK_HASH_REF_REGULAR_NONWEAK);
else
{
if (h->root.u.def.section->owner != NULL
&& (bfd_get_flavour (h->root.u.def.section->owner)
== bfd_target_elf_flavour))
h->elf_link_hash_flags |= (ELF_LINK_HASH_REF_REGULAR
| ELF_LINK_HASH_REF_REGULAR_NONWEAK);
else
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
}
if (h->dynindx == -1
&& ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
|| (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0))
{
if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h))
{
eif->failed = TRUE;
return FALSE;
}
}
}
else
{
/* Unfortunately, ELF_LINK_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->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0
&& (h->root.u.def.section->owner != NULL
? (bfd_get_flavour (h->root.u.def.section->owner)
!= bfd_target_elf_flavour)
: (bfd_is_abs_section (h->root.u.def.section)
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_DYNAMIC) == 0)))
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
}
/* If this is a final link, and the symbol was defined as a common
symbol in a regular object file, and there was no definition in
any dynamic object, then the linker will have allocated space for
the symbol in a common section but the ELF_LINK_HASH_DEF_REGULAR
flag will not have been set. */
if (h->root.type == bfd_link_hash_defined
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0
&& (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
&& (h->root.u.def.section->owner->flags & DYNAMIC) == 0)
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
/* If -Bsymbolic was used (which means to bind references to global
symbols to the definition within the shared object), and this
symbol was defined in a regular object, then it actually doesn't
need a PLT entry. Likewise, if the symbol has non-default
visibility. If the symbol has hidden or internal visibility, we
will force it local. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0
&& eif->info->shared
&& is_elf_hash_table (eif->info->hash)
&& (eif->info->symbolic
|| ELF_ST_VISIBILITY (h->other) != STV_DEFAULT)
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
{
const struct elf_backend_data *bed;
bfd_boolean force_local;
bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj);
force_local = (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL
|| ELF_ST_VISIBILITY (h->other) == STV_HIDDEN);
(*bed->elf_backend_hide_symbol) (eif->info, h, force_local);
}
/* If a weak undefined symbol has non-default visibility, we also
hide it from the dynamic linker. */
if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
&& h->root.type == bfd_link_hash_undefweak)
{
const struct elf_backend_data *bed;
bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj);
(*bed->elf_backend_hide_symbol) (eif->info, h, TRUE);
}
/* If this is a weak defined symbol in a dynamic object, and we know
the real definition in the dynamic object, copy interesting flags
over to the real definition. */
if (h->weakdef != NULL)
{
struct elf_link_hash_entry *weakdef;
weakdef = h->weakdef;
if (h->root.type == bfd_link_hash_indirect)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
BFD_ASSERT (h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak);
BFD_ASSERT (weakdef->root.type == bfd_link_hash_defined
|| weakdef->root.type == bfd_link_hash_defweak);
BFD_ASSERT (weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC);
/* If the real definition is defined by a regular object file,
don't do anything special. See the longer description in
_bfd_elf_adjust_dynamic_symbol, below. */
if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
h->weakdef = NULL;
else
{
const struct elf_backend_data *bed;
bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj);
(*bed->elf_backend_copy_indirect_symbol) (bed, weakdef, h);
}
}
return TRUE;
}
/* Make the backend pick a good value for a dynamic symbol. This is
called via elf_link_hash_traverse, and also calls itself
recursively. */
bfd_boolean
_bfd_elf_adjust_dynamic_symbol (struct elf_link_hash_entry *h, void *data)
{
struct elf_info_failed *eif = data;
bfd *dynobj;
const struct elf_backend_data *bed;
if (! is_elf_hash_table (eif->info->hash))
return FALSE;
if (h->root.type == bfd_link_hash_warning)
{
h->plt = elf_hash_table (eif->info)->init_offset;
h->got = elf_hash_table (eif->info)->init_offset;
/* When warning symbols are created, they **replace** the "real"
entry in the hash table, thus we never get to see the real
symbol in a hash traversal. So look at it now. */
h = (struct elf_link_hash_entry *) h->root.u.i.link;
}
/* Ignore indirect symbols. These are added by the versioning code. */
if (h->root.type == bfd_link_hash_indirect)
return TRUE;
/* Fix the symbol flags. */
if (! _bfd_elf_fix_symbol_flags (h, eif))
return FALSE;
/* If this symbol does not require a PLT entry, and it is not
defined by a dynamic object, or is not referenced by a regular
object, ignore it. We do have to handle a weak defined symbol,
even if no regular object refers to it, if we decided to add it
to the dynamic symbol table. FIXME: Do we normally need to worry
about symbols which are defined by one dynamic object and
referenced by another one? */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0
&& ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
|| (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
|| ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0
&& (h->weakdef == NULL || h->weakdef->dynindx == -1))))
{
h->plt = elf_hash_table (eif->info)->init_offset;
return TRUE;
}
/* If we've already adjusted this symbol, don't do it again. This
can happen via a recursive call. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0)
return TRUE;
/* Don't look at this symbol again. Note that we must set this
after checking the above conditions, because we may look at a
symbol once, decide not to do anything, and then get called
recursively later after REF_REGULAR is set below. */
h->elf_link_hash_flags |= ELF_LINK_HASH_DYNAMIC_ADJUSTED;
/* If this is a weak definition, and we know a real definition, and
the real symbol is not itself defined by a regular object file,
then get a good value for the real definition. We handle the
real symbol first, for the convenience of the backend routine.
Note that there is a confusing case here. If the real definition
is defined by a regular object file, we don't get the real symbol
from the dynamic object, but we do get the weak symbol. If the
processor backend uses a COPY reloc, then if some routine in the
dynamic object changes the real symbol, we will not see that
change in the corresponding weak symbol. This is the way other
ELF linkers work as well, and seems to be a result of the shared
library model.
I will clarify this issue. Most SVR4 shared libraries define the
variable _timezone and define timezone as a weak synonym. The
tzset call changes _timezone. If you write
extern int timezone;
int _timezone = 5;
int main () { tzset (); printf ("%d %d\n", timezone, _timezone); }
you might expect that, since timezone is a synonym for _timezone,
the same number will print both times. However, if the processor
backend uses a COPY reloc, then actually timezone will be copied
into your process image, and, since you define _timezone
yourself, _timezone will not. Thus timezone and _timezone will
wind up at different memory locations. The tzset call will set
_timezone, leaving timezone unchanged. */
if (h->weakdef != NULL)
{
/* If we get to this point, we know there is an implicit
reference by a regular object file via the weak symbol H.
FIXME: Is this really true? What if the traversal finds
H->WEAKDEF before it finds H? */
h->weakdef->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR;
if (! _bfd_elf_adjust_dynamic_symbol (h->weakdef, eif))
return FALSE;
}
/* If a symbol has no type and no size and does not require a PLT
entry, then we are probably about to do the wrong thing here: we
are probably going to create a COPY reloc for an empty object.
This case can arise when a shared object is built with assembly
code, and the assembly code fails to set the symbol type. */
if (h->size == 0
&& h->type == STT_NOTYPE
&& (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0)
(*_bfd_error_handler)
(_("warning: type and size of dynamic symbol `%s' are not defined"),
h->root.root.string);
dynobj = elf_hash_table (eif->info)->dynobj;
bed = get_elf_backend_data (dynobj);
if (! (*bed->elf_backend_adjust_dynamic_symbol) (eif->info, h))
{
eif->failed = TRUE;
return FALSE;
}
return TRUE;
}
/* Adjust all external symbols pointing into SEC_MERGE sections
to reflect the object merging within the sections. */
bfd_boolean
_bfd_elf_link_sec_merge_syms (struct elf_link_hash_entry *h, void *data)
{
asection *sec;
if (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)->flags & SEC_MERGE)
&& sec->sec_info_type == ELF_INFO_TYPE_MERGE)
{
bfd *output_bfd = data;
h->root.u.def.value =
_bfd_merged_section_offset (output_bfd,
&h->root.u.def.section,
elf_section_data (sec)->sec_info,
h->root.u.def.value, 0);
}
return TRUE;
}
/* Returns false if the symbol referred to by H should be considered
to resolve local to the current module, and true if it should be
considered to bind dynamically. */
bfd_boolean
_bfd_elf_dynamic_symbol_p (struct elf_link_hash_entry *h,
struct bfd_link_info *info,
bfd_boolean ignore_protected)
{
bfd_boolean binding_stays_local_p;
if (h == NULL)
return FALSE;
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 it was forced local, then clearly it's not dynamic. */
if (h->dynindx == -1)
return FALSE;
if (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL)
return FALSE;
/* Identify the cases where name binding rules say that a
visible symbol resolves locally. */
binding_stays_local_p = info->executable || info->symbolic;
switch (ELF_ST_VISIBILITY (h->other))
{
case STV_INTERNAL:
case STV_HIDDEN:
return FALSE;
case STV_PROTECTED:
/* Proper resolution for function pointer equality may require
that these symbols perhaps be resolved dynamically, even though
we should be resolving them to the current module. */
if (!ignore_protected)
binding_stays_local_p = TRUE;
break;
default:
break;
}
/* If it isn't defined locally, then clearly it's dynamic. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
return TRUE;
/* Otherwise, the symbol is dynamic if binding rules don't tell
us that it remains local. */
return !binding_stays_local_p;
}
/* Return true if the symbol referred to by H should be considered
to resolve local to the current module, and false otherwise. Differs
from (the inverse of) _bfd_elf_dynamic_symbol_p in the treatment of
undefined symbols and weak symbols. */
bfd_boolean
_bfd_elf_symbol_refs_local_p (struct elf_link_hash_entry *h,
struct bfd_link_info *info,
bfd_boolean local_protected)
{
/* If it's a local sym, of course we resolve locally. */
if (h == NULL)
return TRUE;
/* If we don't have a definition in a regular file, then we can't
resolve locally. The sym is either undefined or dynamic. */
if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
return FALSE;
/* Forced local symbols resolve locally. */
if ((h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0)
return TRUE;
/* As do non-dynamic symbols. */
if (h->dynindx == -1)
return TRUE;
/* At this point, we know the symbol is defined and dynamic. In an
executable it must resolve locally, likewise when building symbolic
shared libraries. */
if (info->executable || info->symbolic)
return TRUE;
/* Now deal with defined dynamic symbols in shared libraries. Ones
with default visibility might not resolve locally. */
if (ELF_ST_VISIBILITY (h->other) == STV_DEFAULT)
return FALSE;
/* However, STV_HIDDEN or STV_INTERNAL ones must be local. */
if (ELF_ST_VISIBILITY (h->other) != STV_PROTECTED)
return TRUE;
/* Function pointer equality tests may require that STV_PROTECTED
symbols be treated as dynamic symbols, even when we know that the
dynamic linker will resolve them locally. */
return local_protected;
}
/* Caches some TLS segment info, and ensures that the TLS segment vma is
aligned. Returns the first TLS output section. */
struct bfd_section *
_bfd_elf_tls_setup (bfd *obfd, struct bfd_link_info *info)
{
struct bfd_section *sec, *tls;
unsigned int align = 0;
for (sec = obfd->sections; sec != NULL; sec = sec->next)
if ((sec->flags & SEC_THREAD_LOCAL) != 0)
break;
tls = sec;
for (; sec != NULL && (sec->flags & SEC_THREAD_LOCAL) != 0; sec = sec->next)
if (sec->alignment_power > align)
align = sec->alignment_power;
elf_hash_table (info)->tls_sec = tls;
/* Ensure the alignment of the first section is the largest alignment,
so that the tls segment starts aligned. */
if (tls != NULL)
tls->alignment_power = align;
return tls;
}
/* Return TRUE iff this is a non-common, definition of a non-function symbol. */
static bfd_boolean
is_global_data_symbol_definition (bfd *abfd ATTRIBUTE_UNUSED,
Elf_Internal_Sym *sym)
{
/* Local symbols do not count, but target specific ones might. */
if (ELF_ST_BIND (sym->st_info) != STB_GLOBAL
&& ELF_ST_BIND (sym->st_info) < STB_LOOS)
return FALSE;
/* Function symbols do not count. */
if (ELF_ST_TYPE (sym->st_info) == STT_FUNC)
return FALSE;
/* If the section is undefined, then so is the symbol. */
if (sym->st_shndx == SHN_UNDEF)
return FALSE;
/* If the symbol is defined in the common section, then
it is a common definition and so does not count. */
if (sym->st_shndx == SHN_COMMON)
return FALSE;
/* If the symbol is in a target specific section then we
must rely upon the backend to tell us what it is. */
if (sym->st_shndx >= SHN_LORESERVE && sym->st_shndx < SHN_ABS)
/* FIXME - this function is not coded yet:
return _bfd_is_global_symbol_definition (abfd, sym);
Instead for now assume that the definition is not global,
Even if this is wrong, at least the linker will behave
in the same way that it used to do. */
return FALSE;
return TRUE;
}
/* Search the symbol table of the archive element of the archive ABFD
whose archive map contains a mention of SYMDEF, and determine if
the symbol is defined in this element. */
static bfd_boolean
elf_link_is_defined_archive_symbol (bfd * abfd, carsym * symdef)
{
Elf_Internal_Shdr * hdr;
bfd_size_type symcount;
bfd_size_type extsymcount;
bfd_size_type extsymoff;
Elf_Internal_Sym *isymbuf;
Elf_Internal_Sym *isym;
Elf_Internal_Sym *isymend;
bfd_boolean result;
abfd = _bfd_get_elt_at_filepos (abfd, symdef->file_offset);
if (abfd == NULL)
return FALSE;
if (! bfd_check_format (abfd, bfd_object))
return FALSE;
/* If we have already included the element containing this symbol in the
link then we do not need to include it again. Just claim that any symbol
it contains is not a definition, so that our caller will not decide to
(re)include this element. */
if (abfd->archive_pass)
return FALSE;
/* Select the appropriate symbol table. */
if ((abfd->flags & DYNAMIC) == 0 || elf_dynsymtab (abfd) == 0)
hdr = &elf_tdata (abfd)->symtab_hdr;
else
hdr = &elf_tdata (abfd)->dynsymtab_hdr;
symcount = hdr->sh_size / get_elf_backend_data (abfd)->s->sizeof_sym;
/* The sh_info field of the symtab header tells us where the
external symbols start. We don't care about the local symbols. */
if (elf_bad_symtab (abfd))
{
extsymcount = symcount;
extsymoff = 0;
}
else
{
extsymcount = symcount - hdr->sh_info;
extsymoff = hdr->sh_info;
}
if (extsymcount == 0)
return FALSE;
/* Read in the symbol table. */
isymbuf = bfd_elf_get_elf_syms (abfd, hdr, extsymcount, extsymoff,
NULL, NULL, NULL);
if (isymbuf == NULL)
return FALSE;
/* Scan the symbol table looking for SYMDEF. */
result = FALSE;
for (isym = isymbuf, isymend = isymbuf + extsymcount; isym < isymend; isym++)
{
const char *name;
name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
isym->st_name);
if (name == NULL)
break;
if (strcmp (name, symdef->name) == 0)
{
result = is_global_data_symbol_definition (abfd, isym);
break;
}
}
free (isymbuf);
return result;
}
/* Add symbols from an ELF archive file to the linker hash table. We
don't use _bfd_generic_link_add_archive_symbols because of a
problem which arises on UnixWare. The UnixWare libc.so is an
archive which includes an entry libc.so.1 which defines a bunch of
symbols. The libc.so archive also includes a number of other
object files, which also define symbols, some of which are the same
as those defined in libc.so.1. Correct linking requires that we
consider each object file in turn, and include it if it defines any
symbols we need. _bfd_generic_link_add_archive_symbols does not do
this; it looks through the list of undefined symbols, and includes
any object file which defines them. When this algorithm is used on
UnixWare, it winds up pulling in libc.so.1 early and defining a
bunch of symbols. This means that some of the other objects in the
archive are not included in the link, which is incorrect since they
precede libc.so.1 in the archive.
Fortunately, ELF archive handling is simpler than that done by
_bfd_generic_link_add_archive_symbols, which has to allow for a.out
oddities. In ELF, if we find a symbol in the archive map, and the
symbol is currently undefined, we know that we must pull in that
object file.
Unfortunately, we do have to make multiple passes over the symbol
table until nothing further is resolved. */
bfd_boolean
_bfd_elf_link_add_archive_symbols (bfd *abfd,
struct bfd_link_info *info)
{
symindex c;
bfd_boolean *defined = NULL;
bfd_boolean *included = NULL;
carsym *symdefs;
bfd_boolean loop;
bfd_size_type amt;
if (! bfd_has_map (abfd))
{
/* An empty archive is a special case. */
if (bfd_openr_next_archived_file (abfd, NULL) == NULL)
return TRUE;
bfd_set_error (bfd_error_no_armap);
return FALSE;
}
/* Keep track of all symbols we know to be already defined, and all
files we know to be already included. This is to speed up the
second and subsequent passes. */
c = bfd_ardata (abfd)->symdef_count;
if (c == 0)
return TRUE;
amt = c;
amt *= sizeof (bfd_boolean);
defined = bfd_zmalloc (amt);
included = bfd_zmalloc (amt);
if (defined == NULL || included == NULL)
goto error_return;
symdefs = bfd_ardata (abfd)->symdefs;
do
{
file_ptr last;
symindex i;
carsym *symdef;
carsym *symdefend;
loop = FALSE;
last = -1;
symdef = symdefs;
symdefend = symdef + c;
for (i = 0; symdef < symdefend; symdef++, i++)
{
struct elf_link_hash_entry *h;
bfd *element;
struct bfd_link_hash_entry *undefs_tail;
symindex mark;
if (defined[i] || included[i])
continue;
if (symdef->file_offset == last)
{
included[i] = TRUE;
continue;
}
h = elf_link_hash_lookup (elf_hash_table (info), symdef->name,
FALSE, FALSE, FALSE);
if (h == NULL)
{
char *p, *copy;
size_t len, first;
/* If this is a default version (the name contains @@),
look up the symbol again with only one `@' as well
as without the version. The effect is that references
to the symbol with and without the version will be
matched by the default symbol in the archive. */
p = strchr (symdef->name, ELF_VER_CHR);
if (p == NULL || p[1] != ELF_VER_CHR)
continue;
/* First check with only one `@'. */
len = strlen (symdef->name);
copy = bfd_alloc (abfd, len);
if (copy == NULL)
goto error_return;
first = p - symdef->name + 1;
memcpy (copy, symdef->name, first);
memcpy (copy + first, symdef->name + first + 1, len - first);
h = elf_link_hash_lookup (elf_hash_table (info), copy,
FALSE, FALSE, FALSE);
if (h == NULL)
{
/* We also need to check references to the symbol
without the version. */
copy[first - 1] = '\0';
h = elf_link_hash_lookup (elf_hash_table (info),
copy, FALSE, FALSE, FALSE);
}
bfd_release (abfd, copy);
}
if (h == NULL)
continue;
if (h->root.type == bfd_link_hash_common)
{
/* We currently have a common symbol. The archive map contains
a reference to this symbol, so we may want to include it. We
only want to include it however, if this archive element
contains a definition of the symbol, not just another common
declaration of it.
Unfortunately some archivers (including GNU ar) will put
declarations of common symbols into their archive maps, as
well as real definitions, so we cannot just go by the archive
map alone. Instead we must read in the element's symbol
table and check that to see what kind of symbol definition
this is. */
if (! elf_link_is_defined_archive_symbol (abfd, symdef))
continue;
}
else if (h->root.type != bfd_link_hash_undefined)
{
if (h->root.type != bfd_link_hash_undefweak)
defined[i] = TRUE;
continue;
}
/* We need to include this archive member. */
element = _bfd_get_elt_at_filepos (abfd, symdef->file_offset);
if (element == NULL)
goto error_return;
if (! bfd_check_format (element, bfd_object))
goto error_return;
/* Doublecheck that we have not included this object
already--it should be impossible, but there may be
something wrong with the archive. */
if (element->archive_pass != 0)
{
bfd_set_error (bfd_error_bad_value);
goto error_return;
}
element->archive_pass = 1;
undefs_tail = info->hash->undefs_tail;
if (! (*info->callbacks->add_archive_element) (info, element,
symdef->name))
goto error_return;
if (! bfd_link_add_symbols (element, info))
goto error_return;
/* If there are any new undefined symbols, we need to make
another pass through the archive in order to see whether
they can be defined. FIXME: This isn't perfect, because
common symbols wind up on undefs_tail and because an
undefined symbol which is defined later on in this pass
does not require another pass. This isn't a bug, but it
does make the code less efficient than it could be. */
if (undefs_tail != info->hash->undefs_tail)
loop = TRUE;
/* Look backward to mark all symbols from this object file
which we have already seen in this pass. */
mark = i;
do
{
included[mark] = TRUE;
if (mark == 0)
break;
--mark;
}
while (symdefs[mark].file_offset == symdef->file_offset);
/* We mark subsequent symbols from this object file as we go
on through the loop. */
last = symdef->file_offset;
}
}
while (loop);
free (defined);
free (included);
return TRUE;
error_return:
if (defined != NULL)
free (defined);
if (included != NULL)
free (included);
return FALSE;
}