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/* Emulation code used by all ELF targets.
Copyright (C) 1991-2020 Free Software Foundation, Inc.
This file is part of the GNU Binutils.
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 "ctf-api.h"
#include "ld.h"
#include "ldmain.h"
#include "ldmisc.h"
#include "ldexp.h"
#include "ldlang.h"
#include "elf-bfd.h"
#include "ldelfgen.h"
void
ldelf_map_segments (bfd_boolean need_layout)
{
int tries = 10;
do
{
lang_relax_sections (need_layout);
need_layout = FALSE;
if (link_info.output_bfd->xvec->flavour == bfd_target_elf_flavour
&& !bfd_link_relocatable (&link_info))
{
bfd_size_type phdr_size;
phdr_size = elf_program_header_size (link_info.output_bfd);
/* If we don't have user supplied phdrs, throw away any
previous linker generated program headers. */
if (lang_phdr_list == NULL)
elf_seg_map (link_info.output_bfd) = NULL;
if (!_bfd_elf_map_sections_to_segments (link_info.output_bfd,
&link_info))
einfo (_("%F%P: map sections to segments failed: %E\n"));
if (phdr_size != elf_program_header_size (link_info.output_bfd))
{
if (tries > 6)
/* The first few times we allow any change to
phdr_size . */
need_layout = TRUE;
else if (phdr_size
< elf_program_header_size (link_info.output_bfd))
/* After that we only allow the size to grow. */
need_layout = TRUE;
else
elf_program_header_size (link_info.output_bfd) = phdr_size;
}
}
}
while (need_layout && --tries);
if (tries == 0)
einfo (_("%F%P: looping in map_segments"));
if (link_info.output_bfd->xvec->flavour == bfd_target_elf_flavour
&& lang_phdr_list == NULL)
{
/* If we don't have user supplied phdrs, strip zero-sized dynamic
sections and regenerate program headers. */
const struct elf_backend_data *bed
= get_elf_backend_data (link_info.output_bfd);
if (bed->elf_backend_strip_zero_sized_dynamic_sections
&& !bed->elf_backend_strip_zero_sized_dynamic_sections
(&link_info))
einfo (_("%F%P: failed to strip zero-sized dynamic sections"));
}
}
#ifdef ENABLE_LIBCTF
/* We want to emit CTF early if and only if we are not targetting ELF with this
invocation. */
int
ldelf_emit_ctf_early (void)
{
if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
return 0;
return 1;
}
/* Callbacks used to map from bfd types to libctf types, under libctf's
control. */
struct ctf_strsym_iter_cb_arg
{
struct elf_sym_strtab *syms;
bfd_size_type symcount;
struct elf_strtab_hash *symstrtab;
size_t next_i;
size_t next_idx;
};
/* Return strings from the strtab to libctf, one by one. Returns NULL when
iteration is complete. */
static const char *
ldelf_ctf_strtab_iter_cb (uint32_t *offset, void *arg_)
{
bfd_size_type off;
const char *ret;
struct ctf_strsym_iter_cb_arg *arg =
(struct ctf_strsym_iter_cb_arg *) arg_;
/* There is no zeroth string. */
if (arg->next_i == 0)
arg->next_i = 1;
if (arg->next_i >= _bfd_elf_strtab_len (arg->symstrtab))
{
arg->next_i = 0;
return NULL;
}
ret = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i++, &off);
*offset = off;
/* If we've overflowed, we cannot share any further strings: the CTF
format cannot encode strings with such high offsets. */
if (*offset != off)
return NULL;
return ret;
}
/* Return symbols from the symbol table to libctf, one by one. We assume (and
assert) that the symbols in the elf_link_hash_table are in strictly ascending
order, and that none will be added in between existing ones. Returns NULL
when iteration is complete. */
static struct ctf_link_sym *
ldelf_ctf_symbols_iter_cb (struct ctf_link_sym *dest,
void *arg_)
{
struct ctf_strsym_iter_cb_arg *arg =
(struct ctf_strsym_iter_cb_arg *) arg_;
if (arg->next_i > arg->symcount)
{
arg->next_i = 0;
arg->next_idx = 0;
return NULL;
}
ASSERT (arg->syms[arg->next_i].dest_index == arg->next_idx);
dest->st_name = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i, NULL);
dest->st_shndx = arg->syms[arg->next_i].sym.st_shndx;
dest->st_type = ELF_ST_TYPE (arg->syms[arg->next_i].sym.st_info);
dest->st_value = arg->syms[arg->next_i].sym.st_value;
arg->next_i++;
return dest;
}
void
ldelf_examine_strtab_for_ctf
(struct ctf_dict *ctf_output, struct elf_sym_strtab *syms,
bfd_size_type symcount, struct elf_strtab_hash *symstrtab)
{
struct ctf_strsym_iter_cb_arg args = { syms, symcount, symstrtab,
0, 0 };
if (!ctf_output)
return;
if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour
&& !bfd_link_relocatable (&link_info))
{
if (ctf_link_add_strtab (ctf_output, ldelf_ctf_strtab_iter_cb,
&args) < 0)
einfo (_("%F%P: warning: CTF strtab association failed; strings will "
"not be shared: %s\n"),
ctf_errmsg (ctf_errno (ctf_output)));
if (ctf_link_shuffle_syms (ctf_output, ldelf_ctf_symbols_iter_cb,
&args) < 0)
einfo (_("%F%P: warning: CTF symbol shuffling failed; slight space "
"cost: %s\n"), ctf_errmsg (ctf_errno (ctf_output)));
}
}
#else
extern int ldelf_emit_ctf_early (void)
{
return 0;
}
extern void ldelf_examine_strtab_for_ctf
(struct ctf_dict *ctf_output ATTRIBUTE_UNUSED,
struct elf_sym_strtab *syms ATTRIBUTE_UNUSED,
bfd_size_type symcount ATTRIBUTE_UNUSED,
struct elf_strtab_hash *symstrtab ATTRIBUTE_UNUSED)
{}
#endif
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