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PR ld/17973 LTO file syms

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LTO output objects have an STT_FILE symbol using the name of the file,
a temporary file.  This results in executables that can't be exactly
reproduced, so the file name needs to be dropped.  We don't want to
lose all file symbols when linking a mix of lto and non-lto objects as
a file symbol can be used to figure which source file generated a
given local symbol.  So lto output objects need to be marked.

I chose to mark lto output objects with a new bfd flag.  This flag is
also used to fix a bug in the link-once handling;  An object being
loaded after "loading_lto_outputs" is set might be one extracted from
an archive to satisfy new references from lto objects, not an lto
object itself.

The new flag is copied from archive to elements, and the same done
for no_export.  This fixes a bug in that --exclude-libs doesn't work
with thin archives.  I'm not completely happy with this part of the
patch and may revist this to avoid the hack in
_bfd_look_for_bfd_in_cache.

	PR ld/17973
include/
	* bfdlink.h (struct bfd_link_info): Delete loading_lto_outputs.
bfd/
	* bfd.c (struct bfd): Add lto_output.
	* linker.c (_bfd_handle_already_linked): Explicitly test for
	objects added by the lto plugin.
	* opncls.c (_bfd_new_bfd_contained_in): Copy lto_output and
	no_export flags from archive.
	* archive.c (open_nested_file): New function, setting lto_output
	and no_export, extracted from..
	(find_nested_archive): ..here.  Flip params.  Rename from
	_bfd_find_nested_archive.
	(_bfd_get_elt_at_filepos): Correct var typo.  Use open_nested_file.
	(_bfd_look_for_bfd_in_cache): Copy no_export.
	* elflink.c (elf_link_add_object_symbols): Remove now unnecessary
	my_archive->no_export test.
	(elf_link_input_bfd): Drop existing lto_output STT_FILE syms.
	Don't use the file name when adding lto_output STT_FILE sym.
	* bfd-in2.h: Regenerate.
ld/
	* ldlang.h (struct lang_input_statement_flags): Add lto_output.
	* ldlang.c (lang_process): Don't set loading_lto_outputs.
	* ldfile.c (ldfile_try_open_bfd): Transfer entry flags.lto_output
	to bfd.
	* plugin.c (add_input_file, add_input_library): Set flags.lto_output.
This commit is contained in:
Alan Modra 2015-02-14 18:38:32 +10:30
parent 0a60f874dc
commit ce875075f9
14 changed files with 121 additions and 48 deletions
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20
bfd/ChangeLog
View File

@ -1,3 +1,23 @@
2015-02-14 Alan Modra <amodra@gmail.com>
PR ld/17973
* bfd.c (struct bfd): Add lto_output.
* linker.c (_bfd_handle_already_linked): Explicitly test for
objects added by the lto plugin.
* opncls.c (_bfd_new_bfd_contained_in): Copy lto_output and
no_export flags from archive.
* archive.c (open_nested_file): New function, setting lto_output
and no_export, extracted from..
(find_nested_archive): ..here. Flip params. Rename from
_bfd_find_nested_archive.
(_bfd_get_elt_at_filepos): Correct var typo. Use open_nested_file.
(_bfd_look_for_bfd_in_cache): Copy no_export.
* elflink.c (elf_link_add_object_symbols): Remove now unnecessary
my_archive->no_export test.
(elf_link_input_bfd): Drop existing lto_output STT_FILE syms.
Don't use the file name when adding lto_output STT_FILE sym.
* bfd-in2.h: Regenerate.
2015-02-13 Alan Modra <amodra@gmail.com>
PR binutils/17512

84
bfd/archive.c
View File

@ -311,8 +311,12 @@ _bfd_look_for_bfd_in_cache (bfd *arch_bfd, file_ptr filepos)
struct ar_cache *entry = (struct ar_cache *) htab_find (hash_table, &m);
if (!entry)
return NULL;
else
return entry->arbfd;
/* Unfortunately this flag is set after checking that we have
an archive, and checking for an archive means one element has
sneaked into the cache. */
entry->arbfd->no_export = arch_bfd->no_export;
return entry->arbfd;
}
else
return NULL;
@ -375,10 +379,27 @@ _bfd_add_bfd_to_archive_cache (bfd *arch_bfd, file_ptr filepos, bfd *new_elt)
}
static bfd *
_bfd_find_nested_archive (bfd *arch_bfd, const char *filename)
open_nested_file (const char *filename, bfd *archive)
{
const char *target;
bfd *n_bfd;
target = NULL;
if (!archive->target_defaulted)
target = archive->xvec->name;
n_bfd = bfd_openr (filename, target);
if (n_bfd != NULL)
{
n_bfd->lto_output = archive->lto_output;
n_bfd->no_export = archive->no_export;
}
return n_bfd;
}
static bfd *
find_nested_archive (const char *filename, bfd *arch_bfd)
{
bfd *abfd;
const char *target;
/* PR 15140: Don't allow a nested archive pointing to itself. */
if (filename_cmp (filename, arch_bfd->filename) == 0)
@ -394,10 +415,7 @@ _bfd_find_nested_archive (bfd *arch_bfd, const char *filename)
if (filename_cmp (filename, abfd->filename) == 0)
return abfd;
}
target = NULL;
if (!arch_bfd->target_defaulted)
target = arch_bfd->xvec->name;
abfd = bfd_openr (filename, target);
abfd = open_nested_file (filename, arch_bfd);
if (abfd)
{
abfd->archive_next = arch_bfd->nested_archives;
@ -626,12 +644,12 @@ bfd *
_bfd_get_elt_at_filepos (bfd *archive, file_ptr filepos)
{
struct areltdata *new_areldata;
bfd *n_nfd;
bfd *n_bfd;
char *filename;
n_nfd = _bfd_look_for_bfd_in_cache (archive, filepos);
if (n_nfd)
return n_nfd;
n_bfd = _bfd_look_for_bfd_in_cache (archive, filepos);
if (n_bfd)
return n_bfd;
if (0 > bfd_seek (archive, filepos, SEEK_SET))
return NULL;
@ -643,8 +661,6 @@ _bfd_get_elt_at_filepos (bfd *archive, file_ptr filepos)
if (bfd_is_thin_archive (archive))
{
const char *target;
/* This is a proxy entry for an external file. */
if (! IS_ABSOLUTE_PATH (filename))
{
@ -660,7 +676,7 @@ _bfd_get_elt_at_filepos (bfd *archive, file_ptr filepos)
{
/* This proxy entry refers to an element of a nested archive.
Locate the member of that archive and return a bfd for it. */
bfd *ext_arch = _bfd_find_nested_archive (archive, filename);
bfd *ext_arch = find_nested_archive (filename, archive);
if (ext_arch == NULL
|| ! bfd_check_format (ext_arch, bfd_archive))
@ -668,57 +684,55 @@ _bfd_get_elt_at_filepos (bfd *archive, file_ptr filepos)
free (new_areldata);
return NULL;
}
n_nfd = _bfd_get_elt_at_filepos (ext_arch, new_areldata->origin);
if (n_nfd == NULL)
n_bfd = _bfd_get_elt_at_filepos (ext_arch, new_areldata->origin);
if (n_bfd == NULL)
{
free (new_areldata);
return NULL;
}
n_nfd->proxy_origin = bfd_tell (archive);
return n_nfd;
n_bfd->proxy_origin = bfd_tell (archive);
return n_bfd;
}
/* It's not an element of a nested archive;
open the external file as a bfd. */
target = NULL;
if (!archive->target_defaulted)
target = archive->xvec->name;
n_nfd = bfd_openr (filename, target);
if (n_nfd == NULL)
n_bfd = open_nested_file (filename, archive);
if (n_bfd == NULL)
bfd_set_error (bfd_error_malformed_archive);
}
else
{
n_nfd = _bfd_create_empty_archive_element_shell (archive);
n_bfd = _bfd_create_empty_archive_element_shell (archive);
}
if (n_nfd == NULL)
if (n_bfd == NULL)
{
free (new_areldata);
return NULL;
}
n_nfd->proxy_origin = bfd_tell (archive);
n_bfd->proxy_origin = bfd_tell (archive);
if (bfd_is_thin_archive (archive))
{
n_nfd->origin = 0;
n_bfd->origin = 0;
}
else
{
n_nfd->origin = n_nfd->proxy_origin;
n_nfd->filename = xstrdup (filename);
n_bfd->origin = n_bfd->proxy_origin;
n_bfd->filename = xstrdup (filename);
}
n_nfd->arelt_data = new_areldata;
n_bfd->arelt_data = new_areldata;
/* Copy BFD_COMPRESS and BFD_DECOMPRESS flags. */
n_nfd->flags |= archive->flags & (BFD_COMPRESS | BFD_DECOMPRESS);
n_bfd->flags |= archive->flags & (BFD_COMPRESS | BFD_DECOMPRESS);
if (_bfd_add_bfd_to_archive_cache (archive, filepos, n_nfd))
return n_nfd;
if (_bfd_add_bfd_to_archive_cache (archive, filepos, n_bfd))
return n_bfd;
free (new_areldata);
n_nfd->arelt_data = NULL;
n_bfd->arelt_data = NULL;
return NULL;
}

3
bfd/bfd-in2.h
View File

@ -6438,6 +6438,9 @@ struct bfd
/* If this is an input for a compiler plug-in library. */
ENUM_BITFIELD (bfd_plugin_format) plugin_format : 2;
/* Set if this is a plugin output file. */
unsigned int lto_output : 1;
/* Set to dummy BFD created when claimed by a compiler plug-in
library. */
bfd *plugin_dummy_bfd;

3
bfd/bfd.c
View File

@ -210,6 +210,9 @@ CODE_FRAGMENT
. {* If this is an input for a compiler plug-in library. *}
. ENUM_BITFIELD (bfd_plugin_format) plugin_format : 2;
.
. {* Set if this is a plugin output file. *}
. unsigned int lto_output : 1;
.
. {* Set to dummy BFD created when claimed by a compiler plug-in
. library. *}
. bfd *plugin_dummy_bfd;

13
bfd/elflink.c
View File

@ -4085,8 +4085,7 @@ error_free_dyn:
requested we not re-export it, then mark it as hidden. */
if (definition
&& !dynamic
&& (abfd->no_export
|| (abfd->my_archive && abfd->my_archive->no_export))
&& abfd->no_export
&& ELF_ST_VISIBILITY (isym->st_other) != STV_INTERNAL)
isym->st_other = (STV_HIDDEN
| (isym->st_other & ~ELF_ST_VISIBILITY (-1)));
@ -9520,6 +9519,10 @@ elf_link_input_bfd (struct elf_final_link_info *flinfo, bfd *input_bfd)
if (ELF_ST_TYPE (isym->st_info) == STT_FILE)
{
if (input_bfd->lto_output)
/* -flto puts a temp file name here. This means builds
are not reproducible. Discard the symbol. */
continue;
have_file_sym = TRUE;
flinfo->filesym_count += 1;
}
@ -9536,8 +9539,10 @@ elf_link_input_bfd (struct elf_final_link_info *flinfo, bfd *input_bfd)
memset (&osym, 0, sizeof (osym));
osym.st_info = ELF_ST_INFO (STB_LOCAL, STT_FILE);
osym.st_shndx = SHN_ABS;
if (!elf_link_output_sym (flinfo, input_bfd->filename, &osym,
bfd_abs_section_ptr, NULL))
if (!elf_link_output_sym (flinfo,
(input_bfd->lto_output ? NULL
: input_bfd->filename),
&osym, bfd_abs_section_ptr, NULL))
return FALSE;
}

2
bfd/linker.c
View File

@ -2896,7 +2896,7 @@ _bfd_handle_already_linked (asection *sec,
files over IR because the first pass may contain a
mix of LTO and normal objects and we must keep the
first match, be it IR or real. */
if (info->loading_lto_outputs
if (sec->owner->lto_output
&& (l->sec->owner->flags & BFD_PLUGIN) != 0)
{
l->sec = sec;

2
bfd/opncls.c
View File

@ -109,6 +109,8 @@ _bfd_new_bfd_contained_in (bfd *obfd)
nbfd->my_archive = obfd;
nbfd->direction = read_direction;
nbfd->target_defaulted = obfd->target_defaulted;
nbfd->lto_output = obfd->lto_output;
nbfd->no_export = obfd->no_export;
return nbfd;
}

5
include/ChangeLog
View File

@ -1,3 +1,8 @@
2015-02-14 Alan Modra <amodra@gmail.com>
PR ld/17973
* bfdlink.h (struct bfd_link_info): Delete loading_lto_outputs.
2015-02-09 Mark Wielaard <mjw@redhat.com>
* dwarf2.h: Add DW_LANG_Fortran03 and DW_LANG_Fortran08.

3
include/bfdlink.h
View File

@ -301,9 +301,6 @@ struct bfd_link_info
/* TRUE if the LTO plugin is active. */
unsigned int lto_plugin_active: 1;
/* TRUE if we are loading LTO outputs. */
unsigned int loading_lto_outputs: 1;
/* TRUE if global symbols in discarded sections should be stripped. */
unsigned int strip_discarded: 1;

9
ld/ChangeLog
View File

@ -1,3 +1,12 @@
2015-02-14 Alan Modra <amodra@gmail.com>
PR ld/17973
* ldlang.h (struct lang_input_statement_flags): Add lto_output.
* ldlang.c (lang_process): Don't set loading_lto_outputs.
* ldfile.c (ldfile_try_open_bfd): Transfer entry flags.lto_output
to bfd.
* plugin.c (add_input_file, add_input_library): Set flags.lto_output.
2015-02-13 H.J. Lu <hongjiu.lu@intel.com>
* NEWS: Mention support for LLVM plugin.

5
ld/ldfile.c
View File

@ -142,6 +142,11 @@ ldfile_try_open_bfd (const char *attempt,
/* Linker needs to decompress sections. */
entry->the_bfd->flags |= BFD_DECOMPRESS;
#ifdef ENABLE_PLUGINS
if (entry->flags.lto_output)
entry->the_bfd->lto_output = 1;
#endif
/* If we are searching for this file, see if the architecture is
compatible with the output file. If it isn't, keep searching.
If we can't open the file as an object file, stop the search

1
ld/ldlang.c
View File

@ -6643,7 +6643,6 @@ lang_process (void)
einfo (_("%P%F: %s: plugin reported error after all symbols read\n"),
plugin_error_plugin ());
/* Open any newly added files, updating the file chains. */
link_info.loading_lto_outputs = TRUE;
open_input_bfds (*added.tail, OPEN_BFD_NORMAL);
/* Restore the global list pointer now they have all been added. */
lang_list_remove_tail (stat_ptr, &added);

3
ld/ldlang.h
View File

@ -283,6 +283,9 @@ struct lang_input_statement_flags
/* Set if the file was claimed from an archive. */
unsigned int claim_archive : 1;
/* Set if added by the lto plugin add_input_file callback. */
unsigned int lto_output : 1;
#endif /* ENABLE_PLUGINS */
/* Head of list of pushed flags. */

16
ld/plugin.c
View File

@ -772,10 +772,14 @@ get_symbols_v2 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
static enum ld_plugin_status
add_input_file (const char *pathname)
{
lang_input_statement_type *is;
ASSERT (called_plugin);
if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
NULL))
is = lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
NULL);
if (!is)
return LDPS_ERR;
is->flags.lto_output = 1;
return LDPS_OK;
}
@ -783,10 +787,14 @@ add_input_file (const char *pathname)
static enum ld_plugin_status
add_input_library (const char *pathname)
{
lang_input_statement_type *is;
ASSERT (called_plugin);
if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
NULL))
is = lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
NULL);
if (!is)
return LDPS_ERR;
is->flags.lto_output = 1;
return LDPS_OK;
}