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/* LTO plugin for gold.
Copyright (C) 2009, 2010 Free Software Foundation, Inc.
Contributed by Rafael Avila de Espindola (espindola@google.com).
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, 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; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <libiberty.h>
#include <stdlib.h>
#include <inttypes.h>
/* The presence of gelf.h is checked by the toplevel configure script. */
#include <gelf.h>
/* Common definitions that the object format dependent code needs. */
#include "lto-plugin.h"
/* Process all lto symtabs of file ELF. */
static int
process_symtab (Elf *elf, struct plugin_symtab *out)
{
int found = 0;
Elf_Scn *section = 0;
GElf_Ehdr header;
GElf_Ehdr *t = gelf_getehdr (elf, &header);
if (t == NULL)
return 0;
assert (t == &header);
while ((section = elf_nextscn(elf, section)) != 0)
{
GElf_Shdr shdr;
GElf_Shdr *tshdr = gelf_getshdr (section, &shdr);
Elf_Data *symtab;
const char *t;
assert (tshdr == &shdr);
t = elf_strptr (elf, header.e_shstrndx, shdr.sh_name);
assert (t != NULL);
if (strncmp (t, LTO_SECTION_PREFIX, strlen (LTO_SECTION_PREFIX)) == 0)
{
char *s = strrchr (t, '.');
if (s)
sscanf (s, ".%x", &out->id);
symtab = elf_getdata (section, NULL);
translate (symtab->d_buf, symtab->d_buf + symtab->d_size, out);
found++;
}
}
return found;
}
/* Callback used by gold to check if the plugin will claim FILE. Writes
the result in CLAIMED. */
enum ld_plugin_status
claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
{
enum ld_plugin_status status;
Elf *elf;
struct plugin_file_info lto_file;
int n;
memset (<o_file, 0, sizeof (struct plugin_file_info));
if (file->offset != 0)
{
char *objname;
Elf *archive;
off_t offset;
/* We pass the offset of the actual file, not the archive header. */
int t = asprintf (&objname, "%s@0x%" PRIx64, file->name,
(int64_t) file->offset);
check (t >= 0, LDPL_FATAL, "asprintf failed");
lto_file.name = objname;
archive = elf_begin (file->fd, ELF_C_READ, NULL);
check (elf_kind (archive) == ELF_K_AR, LDPL_FATAL,
"Not an archive and offset not 0");
/* elf_rand expects the offset to point to the ar header, not the
object itself. Subtract the size of the ar header (60 bytes).
We don't uses sizeof (struct ar_hd) to avoid including ar.h */
offset = file->offset - 60;
check (offset == elf_rand (archive, offset), LDPL_FATAL,
"could not seek in archive");
elf = elf_begin (file->fd, ELF_C_READ, archive);
check (elf != NULL, LDPL_FATAL, "could not find archive member");
elf_end (archive);
}
else
{
lto_file.name = xstrdup (file->name);
elf = elf_begin (file->fd, ELF_C_READ, NULL);
}
lto_file.handle = file->handle;
*claimed = 0;
if (!elf)
goto err;
n = process_symtab (elf, <o_file.symtab);
if (n == 0)
goto err;
if (n > 1)
resolve_conflicts (<o_file.symtab, <o_file.conflicts);
status = add_symbols (file->handle, lto_file.symtab.nsyms,
lto_file.symtab.syms);
check (status == LDPS_OK, LDPL_FATAL, "could not add symbols");
*claimed = 1;
num_claimed_files++;
claimed_files =
xrealloc (claimed_files,
num_claimed_files * sizeof (struct plugin_file_info));
claimed_files[num_claimed_files - 1] = lto_file;
goto cleanup;
err:
free (lto_file.name);
cleanup:
if (elf)
elf_end (elf);
return LDPS_OK;
}
/* Method called first thing at onload time to perform sanity checks. */
enum ld_plugin_status
onload_format_checks (struct ld_plugin_tv *tv)
{
unsigned version = elf_version (EV_CURRENT);
check (version != EV_NONE, LDPL_FATAL, "invalid ELF version");
return LDPS_OK;
}
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