205 lines
6.7 KiB
C
205 lines
6.7 KiB
C
/* ELF linking support for BFD.
|
|
Copyright 1995 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
|
|
|
|
#include "bfd.h"
|
|
#include "sysdep.h"
|
|
#include "bfdlink.h"
|
|
#include "libbfd.h"
|
|
#define ARCH_SIZE 0
|
|
#include "libelf.h"
|
|
|
|
boolean
|
|
_bfd_elf_create_got_section (abfd, info)
|
|
bfd *abfd;
|
|
struct bfd_link_info *info;
|
|
{
|
|
flagword flags;
|
|
register asection *s;
|
|
struct elf_link_hash_entry *h;
|
|
struct elf_backend_data *bed = get_elf_backend_data (abfd);
|
|
|
|
/* This function may be called more than once. */
|
|
if (bfd_get_section_by_name (abfd, ".got") != NULL)
|
|
return true;
|
|
|
|
flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
|
|
|
|
s = bfd_make_section (abfd, ".got");
|
|
if (s == NULL
|
|
|| !bfd_set_section_flags (abfd, s, flags)
|
|
|| !bfd_set_section_alignment (abfd, s, 2))
|
|
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, 2))
|
|
return false;
|
|
}
|
|
|
|
/* 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 = NULL;
|
|
if (!(_bfd_generic_link_add_one_symbol
|
|
(info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s, (bfd_vma) 0,
|
|
(const char *) NULL, false, get_elf_backend_data (abfd)->collect,
|
|
(struct bfd_link_hash_entry **) &h)))
|
|
return false;
|
|
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
|
|
h->type = STT_OBJECT;
|
|
|
|
if (info->shared
|
|
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
|
|
return false;
|
|
|
|
/* The first three global offset table entries are reserved. */
|
|
s->_raw_size += 3 * 4;
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Create dynamic sections when linking against a dynamic object. */
|
|
|
|
boolean
|
|
_bfd_elf_create_dynamic_sections (abfd, info)
|
|
bfd *abfd;
|
|
struct bfd_link_info *info;
|
|
{
|
|
flagword flags;
|
|
register asection *s;
|
|
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;
|
|
|
|
s = bfd_make_section (abfd, ".plt");
|
|
if (s == NULL
|
|
|| ! bfd_set_section_flags (abfd, s,
|
|
(flags | SEC_CODE
|
|
| (bed->plt_readonly ? SEC_READONLY : 0)))
|
|
|| ! bfd_set_section_alignment (abfd, s, 2))
|
|
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 = NULL;
|
|
if (! (_bfd_generic_link_add_one_symbol
|
|
(info, abfd, "_PROCEDURE_LINKAGE_TABLE_", BSF_GLOBAL, s,
|
|
(bfd_vma) 0, (const char *) NULL, false,
|
|
get_elf_backend_data (abfd)->collect,
|
|
(struct bfd_link_hash_entry **) &h)))
|
|
return false;
|
|
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
|
|
h->type = STT_OBJECT;
|
|
|
|
if (info->shared
|
|
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
|
|
return false;
|
|
}
|
|
|
|
s = bfd_make_section (abfd, bed->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, 2))
|
|
return false;
|
|
|
|
if (! _bfd_elf_create_got_section (abfd, info))
|
|
return false;
|
|
|
|
/* 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))
|
|
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->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, 2))
|
|
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. */
|
|
|
|
boolean
|
|
_bfd_elf_link_record_dynamic_symbol (info, h)
|
|
struct bfd_link_info *info;
|
|
struct elf_link_hash_entry *h;
|
|
{
|
|
if (h->dynindx == -1)
|
|
{
|
|
struct bfd_strtab_hash *dynstr;
|
|
|
|
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_stringtab_init ();
|
|
if (dynstr == NULL)
|
|
return false;
|
|
}
|
|
|
|
h->dynstr_index = ((unsigned long)
|
|
_bfd_stringtab_add (dynstr, h->root.root.string,
|
|
true, false));
|
|
if (h->dynstr_index == (unsigned long) -1)
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|