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strip: Add GCC LTO IR support

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Add GCC LTO IR support to strip by copying GCC LTO IR input as unknown
object file.  Don't enable LTO plugin in strip unless all LTO sections
should be removed, assuming all LTO sections will be removed with
-R .gnu.lto_.*.  Add linker LTO tests for strip with --strip-unneeded
and GCC LTO IR inputs.

binutils/

	PR binutils/21479
	* objcopy.c: Include "plugin-api.h" and "plugin.h".
	(lto_sections_removed): New.
	(command_line_switch): Add OPTION_PLUGIN.
	(strip_options): Likewise.
	(strip_usage): Display "--plugin NAME".
	(copy_unknown_file): New function.
	(copy_unknown_object): Call copy_unknown_file.
	(copy_archive): Copy input LTO IR member as unknown object.
	(copy_file): Set input target to "plugin" for strip if it is
	unset unless all LTO sections should be removed.  Copy input
	LTO IR file as unknown file.
	(strip_main): Call bfd_plugin_set_program_name. Handle
	OPTION_PLUGIN.  Set lto_sections_removed to true if all GCC
	LTO sections should be removed.
	* doc/binutils.texi: Document --plugin for strip.

ld/

	PR binutils/21479
	* testsuite/ld-plugin/lto-binutils.exp: New file.
	* testsuite/ld-plugin/strip-1a-fat.c: Likewise.
	* testsuite/ld-plugin/strip-1a-fat.rd: Likewise.
	* testsuite/ld-plugin/strip-1b-fat.c: Likewise.
	* testsuite/ld-plugin/strip-1b-fat.rd: Likewise.
	* testsuite/ld-plugin/strip-1a.c: Likewise.
	* testsuite/ld-plugin/strip-1b.c: Likewise.
	* testsuite/lib/ld-lib.exp (run_cc_link_tests): Add optional
	trailing ld options.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
This commit is contained in:
H.J. Lu
2025-05-04 05:12:46 +08:00
parent 6ebd38072d
commit 717a38e9a0
10 changed files with 481 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
binutils/doc/binutils.texi
View File

@@ -3566,6 +3566,7 @@ strip [@option{-F} @var{bfdname} |@option{--target=}@var{bfdname}]
[@option{--keep-section-symbols}]
[@option{--keep-file-symbols}]
[@option{--only-keep-debug}]
[@option{--plugin} @var{name}]
[@option{-v} |@option{--verbose}] [@option{-V}|@option{--version}]
[@option{--help}] [@option{--info}]
@var{objfile}@dots{}
@@ -3825,6 +3826,26 @@ currently only supports the presence of one filename containing
debugging information, not multiple filenames on a one-per-object-file
basis.
@item --plugin @var{name}
@cindex plugins
Load the plugin called @var{name} to add support for extra target
types. This option is only available if the toolchain has been built
with plugin support enabled.
If @option{--plugin} is not provided, but plugin support has been
enabled then @command{strip} iterates over the files in
@file{$@{libdir@}/bfd-plugins} in alphabetic order and the first
plugin that claims the object in question is used.
Please note that this plugin search directory is @emph{not} the one
used by @command{ld}'s @option{-plugin} option. In order to make
@command{strip} use the linker plugin it must be copied into the
@file{$@{libdir@}/bfd-plugins} directory. For GCC based compilations
the linker plugin is called @file{liblto_plugin.so.0.0.0}. For Clang
based compilations it is called @file{LLVMgold.so}. The GCC plugin
is always backwards compatible with earlier versions, so it is
sufficient to just copy the newest one.
@item -V
@itemx --version
Show the version number for @command{strip}.

115
binutils/objcopy.c
View File

@@ -30,6 +30,8 @@
#include "coff/internal.h"
#include "libcoff.h"
#include "safe-ctype.h"
#include "plugin-api.h"
#include "plugin.h"
/* FIXME: See bfd/peXXigen.c for why we include an architecture specific
header in generic PE code. */
@@ -165,6 +167,11 @@ static struct section_list *change_sections;
/* TRUE if some sections are to be removed. */
static bool sections_removed;
#if BFD_SUPPORTS_PLUGINS
/* TRUE if all GCC LTO sections are to be removed. */
static bool lto_sections_removed;
#endif
/* TRUE if only some sections are to be copied. */
static bool sections_copied;
@@ -359,6 +366,7 @@ enum command_line_switch
OPTION_RENAME_SECTION,
OPTION_REVERSE_BYTES,
OPTION_PE_SECTION_ALIGNMENT,
OPTION_PLUGIN,
OPTION_SET_SECTION_FLAGS,
OPTION_SET_SECTION_ALIGNMENT,
OPTION_SET_START,
@@ -402,6 +410,7 @@ static struct option strip_options[] =
{"output-file", required_argument, 0, 'o'},
{"output-format", required_argument, 0, 'O'}, /* Obsolete */
{"output-target", required_argument, 0, 'O'},
{"plugin", required_argument, 0, OPTION_PLUGIN},
{"preserve-dates", no_argument, 0, 'p'},
{"remove-section", required_argument, 0, 'R'},
{"remove-relocations", required_argument, 0, OPTION_REMOVE_RELOCS},
@@ -758,6 +767,10 @@ strip_usage (FILE *stream, int exit_status)
--info List object formats & architectures supported\n\
-o <file> Place stripped output into <file>\n\
"));
#if BFD_SUPPORTS_PLUGINS
fprintf (stream, _("\
--plugin NAME Load the specified plugin\n"));
#endif
list_supported_targets (program_name, stream);
if (REPORT_BUGS_TO[0] && exit_status == 0)
@@ -1916,20 +1929,11 @@ add_redefine_syms_file (const char *filename)
Returns TRUE upon success, FALSE otherwise. */
static bool
copy_unknown_object (bfd *ibfd, bfd *obfd)
copy_unknown_file (bfd *ibfd, bfd *obfd, off_t size, unsigned int mode)
{
char *cbuf;
bfd_size_type tocopy;
off_t size;
struct stat buf;
if (bfd_stat_arch_elt (ibfd, &buf) != 0)
{
bfd_nonfatal_message (NULL, ibfd, NULL, NULL);
return false;
}
size = buf.st_size;
if (size < 0)
{
non_fatal (_("stat returns negative size for `%s'"),
@@ -1974,11 +1978,31 @@ copy_unknown_object (bfd *ibfd, bfd *obfd)
/* We should at least to be able to read it back when copying an
unknown object in an archive. */
chmod (bfd_get_filename (obfd), buf.st_mode | S_IRUSR);
chmod (bfd_get_filename (obfd), mode | S_IRUSR);
free (cbuf);
return true;
}
/* Copy unknown object file archive member IBFD onto OBFD.
Returns TRUE upon success, FALSE otherwise. */
static bool
copy_unknown_object (bfd *ibfd, bfd *obfd)
{
struct stat buf;
if (bfd_stat_arch_elt (ibfd, &buf) != 0)
{
bfd_nonfatal_message (NULL, ibfd, NULL, NULL);
return false;
}
if (!copy_unknown_file (ibfd, obfd, buf.st_size, buf.st_mode))
return false;
return true;
}
typedef struct objcopy_internal_note
{
Elf_Internal_Note note;
@@ -3744,6 +3768,12 @@ copy_archive (bfd *ibfd, bfd *obfd, const char *output_target,
goto cleanup_and_exit;
}
#if BFD_SUPPORTS_PLUGINS
/* Copy LTO IR file as unknown object. */
if (bfd_plugin_target_p (ibfd->xvec))
ok_object = false;
else
#endif
if (ok_object)
{
ok = copy_object (this_element, output_element, input_arch);
@@ -3845,6 +3875,7 @@ copy_file (const char *input_filename, const char *output_filename, int ofd,
char **obj_matching;
char **core_matching;
off_t size = get_file_size (input_filename);
const char *target = input_target;
if (size < 1)
{
@@ -3855,9 +3886,16 @@ copy_file (const char *input_filename, const char *output_filename, int ofd,
return;
}
#if BFD_SUPPORTS_PLUGINS
/* Enable LTO plugin in strip unless all LTO sections should be
removed. */
if (is_strip && !target && !lto_sections_removed)
target = "plugin";
#endif
/* To allow us to do "strip *" without dying on the first
non-object file, failures are nonfatal. */
ibfd = bfd_openr (input_filename, input_target);
ibfd = bfd_openr (input_filename, target);
if (ibfd == NULL || bfd_stat (ibfd, in_stat) != 0)
{
bfd_nonfatal_message (input_filename, NULL, NULL, NULL);
@@ -3974,17 +4012,31 @@ copy_file (const char *input_filename, const char *output_filename, int ofd,
return;
}
if (! copy_object (ibfd, obfd, input_arch))
status = 1;
/* PR 17512: file: 0f15796a.
If the file could not be copied it may not be in a writeable
state. So use bfd_close_all_done to avoid the possibility of
writing uninitialised data into the file. */
if (! (status ? bfd_close_all_done (obfd) : bfd_close (obfd)))
#if BFD_SUPPORTS_PLUGINS
if (bfd_plugin_target_p (ibfd->xvec))
{
status = 1;
bfd_nonfatal_message (output_filename, NULL, NULL, NULL);
/* Copy LTO IR file as unknown file. */
if (!copy_unknown_file (ibfd, obfd, in_stat->st_size,
in_stat->st_mode))
status = 1;
else if (!bfd_close_all_done (obfd))
status = 1;
}
else
#endif
{
if (! copy_object (ibfd, obfd, input_arch))
status = 1;
/* PR 17512: file: 0f15796a.
If the file could not be copied it may not be in a writeable
state. So use bfd_close_all_done to avoid the possibility of
writing uninitialised data into the file. */
if (! (status ? bfd_close_all_done (obfd) : bfd_close (obfd)))
{
status = 1;
bfd_nonfatal_message (output_filename, NULL, NULL, NULL);
}
}
if (!bfd_close (ibfd))
@@ -4837,6 +4889,10 @@ strip_main (int argc, char *argv[])
char *output_file = NULL;
bool merge_notes_set = false;
#if BFD_SUPPORTS_PLUGINS
bfd_plugin_set_program_name (argv[0]);
#endif
while ((c = getopt_long (argc, argv, "I:O:F:K:MN:R:o:sSpdgxXHhVvwDU",
strip_options, (int *) 0)) != EOF)
{
@@ -4927,6 +4983,13 @@ strip_main (int argc, char *argv[])
case OPTION_KEEP_SECTION_SYMBOLS:
keep_section_symbols = true;
break;
case OPTION_PLUGIN: /* --plugin */
#if BFD_SUPPORTS_PLUGINS
bfd_plugin_set_plugin (optarg);
#else
fatal (_("sorry - this program has been built without plugin support\n"));
#endif
break;
case 0:
/* We've been given a long option. */
break;
@@ -4971,6 +5034,14 @@ strip_main (int argc, char *argv[])
if (output_target == NULL)
output_target = input_target;
#if BFD_SUPPORTS_PLUGINS
/* Check if all GCC LTO sections should be removed, assuming all LTO
sections will be removed with -R .gnu.lto_.*. * Remove .gnu.lto_.*
sections will also remove .gnu.debuglto_. sections. */
lto_sections_removed = !!find_section_list (".gnu.lto_.*", false,
SECTION_CONTEXT_REMOVE);
#endif
i = optind;
if (i == argc
|| (output_file != NULL && (i + 1) < argc))

341
ld/testsuite/ld-plugin/lto-binutils.exp Normal file
View File

@@ -0,0 +1,341 @@
# Expect script for binutils tests with LTO
# Copyright (C) 2025 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.
#
# Make sure that binutils can correctly handle LTO IR in ELF.
if { !([istarget *-*-linux*]
|| [istarget arm*-*-uclinuxfdpiceabi]
|| [istarget *-*-nacl*]
|| [istarget *-*-gnu*]) || [istarget *ecoff] } then {
return
}
# Check to see if the C and C++ compilers work
if { ![check_compiler_available] || [which $CXX_FOR_TARGET] == 0 } {
return
}
# These tests require plugin and LTO.
if { ![check_plugin_api_available]
|| ![check_lto_available] } {
return
}
set lto_fat ""
set lto_no_fat ""
if { [check_lto_fat_available] } {
set lto_fat "-ffat-lto-objects"
set lto_no_fat "-fno-fat-lto-objects"
set no_lto "-fno-lto"
}
set lto_plugin [string trim [run_host_cmd "$CC_FOR_TARGET" "-print-prog-name=liblto_plugin.so"]]
# List contains test-items:
# 0:program name
# 1:program options
# 2:input file
# 3:output file
# 4:action list (optional)
#
proc run_lto_binutils_test { lto_tests } {
global srcdir
global subdir
global nm
global objcopy
global objdump
global READELF
global strip
global lto_plugin
foreach testitem $lto_tests {
set prog_name [lindex $testitem 0]
set prog_options [lindex $testitem 1]
set input tmpdir/[lindex $testitem 2]
set output tmpdir/[lindex $testitem 3]
set actions [lindex $testitem 4]
set objfiles {}
set is_unresolved 0
set failed 0
# eval set prog \$$prog_name
switch -- $prog_name {
objcopy
{
set prog $objcopy
set prog_output "$output"
}
strip
{
set prog $strip
set prog_output "-o $output"
}
default
{
perror "Unrecognized action $action"
set is_unresolved 1
break
}
}
# Don't leave previous output around
if { $output ne "tmpdir/" } {
remote_file host delete $output
}
append prog_options " --plugin $lto_plugin"
set cmd_options "$prog_options $prog_output $input"
set test_name "$prog_name $cmd_options"
set cmd "$prog $cmd_options"
send_log "$cmd\n"
set got [remote_exec host "$cmd"]
if { [lindex $got 0] != 0 || ![string match "" [lindex $got 1]] } then {
send_log "$got\n"
fail "$test_name"
continue
}
if { $failed == 0 } {
foreach actionlist $actions {
set action [lindex $actionlist 0]
set progopts [lindex $actionlist 1]
# There are actions where we run regexp_diff on the
# output, and there are other actions (presumably).
# Handling of the former look the same.
set dump_prog ""
switch -- $action {
objdump
{ set dump_prog $objdump }
nm
{ set dump_prog $nm }
readelf
{ set dump_prog $READELF }
default
{
perror "Unrecognized action $action"
set is_unresolved 1
break
}
}
if { $dump_prog != "" } {
set dumpfile [lindex $actionlist 2]
set binary $dump_prog
# Ensure consistent sorting of symbols
if {[info exists env(LC_ALL)]} {
set old_lc_all $env(LC_ALL)
}
set env(LC_ALL) "C"
set cmd "$binary $progopts $output > tmpdir/dump.out"
send_log "$cmd\n"
catch "exec $cmd" comp_output
if {[info exists old_lc_all]} {
set env(LC_ALL) $old_lc_all
} else {
unset env(LC_ALL)
}
set comp_output [prune_warnings $comp_output]
if ![string match "" $comp_output] then {
send_log "$comp_output\n"
set failed 1
break
}
if { [regexp_diff "tmpdir/dump.out" "$srcdir/$subdir/$dumpfile"] } then {
verbose -log "output is [file_contents "tmpdir/dump.out"]" 2
set failed 1
break
}
}
}
}
if { $failed } {
fail $test_name
} elseif { $is_unresolved } {
unresolved $test_name
} else {
pass $test_name
}
}
}
run_cc_link_tests [list \
[list \
"Build strip-1a.o" \
"" \
"-O2 -flto $lto_no_fat" \
{ strip-1a.c } \
] \
[list \
"Build libstrip-1a.a" \
"--plugin $lto_plugin" \
"-O2 -flto $lto_no_fat" \
{ strip-1a.c } \
{} \
"libstrip-1a.a" \
] \
[list \
"Build strip-1a-fat.o" \
"" \
"-O2 -flto $lto_fat" \
{ strip-1a-fat.c } \
] \
[list \
"Build libstrip-1a-fat.a" \
"--plugin $lto_plugin" \
"-O2 -flto $lto_fat" \
{ strip-1a-fat.c } \
{} \
"libstrip-1a-fat.a" \
] \
]
run_lto_binutils_test [list \
[list \
"strip" \
"--strip-unneeded" \
"libstrip-1a.a" \
"libstrip-1a-s.a" \
] \
[list \
"strip" \
"--strip-unneeded" \
"strip-1a.o" \
"strip-1a-s.o" \
] \
[list \
"strip" \
"--strip-unneeded -R .gnu.*lto_* -N __gnu_lto_v1" \
"libstrip-1a-fat.a" \
"libstrip-1a-fat-s.a" \
{{readelf -SW strip-1a-fat.rd}} \
] \
[list \
"strip" \
"--strip-unneeded -R .gnu.*lto_* -N __gnu_lto_v1" \
"strip-1a-fat.o" \
"strip-1a-fat-s.o" \
{{readelf -SW strip-1a-fat.rd}} \
] \
[list \
"strip" \
"--strip-unneeded -R .gnu.debuglto_*" \
"libstrip-1a-fat.a" \
"libstrip-1b-fat-s.a" \
{{readelf -SW strip-1b-fat.rd}} \
] \
[list \
"strip" \
"--strip-unneeded -R .gnu.debuglto_*" \
"strip-1a-fat.o" \
"strip-1b-fat-s.o" \
{{readelf -SW strip-1b-fat.rd}} \
] \
]
run_cc_link_tests [list \
[list \
"Build strip-1a (strip-1a.o)" \
"" \
"-O2 -flto $lto_no_fat" \
{ strip-1b.c } \
{} \
"libstrip-1a" \
"C" \
"tmpdir/strip-1a.o" \
] \
[list \
"Build strip-1b (strip-1a-s.o)" \
"" \
"-O2 -flto $lto_no_fat" \
{ strip-1b.c } \
{} \
"libstrip-1b" \
"C" \
"tmpdir/strip-1a-s.o" \
] \
[list \
"Build strip-1c (libstrip-1a.a)" \
"" \
"-O2 -flto $lto_no_fat" \
{ strip-1b.c } \
{} \
"libstrip-1c" \
"C" \
"tmpdir/libstrip-1a.a" \
] \
[list \
"Build strip-1d (libstrip-1a-s.a)" \
"" \
"-O2 -flto $lto_no_fat" \
{ strip-1b.c } \
{} \
"libstrip-1d" \
"C" \
"tmpdir/libstrip-1a-s.a" \
] \
[list \
"Build strip-1e (strip-1a-fat-s.o)" \
"" \
"-O2 -flto $lto_fat" \
{ strip-1b-fat.c } \
{} \
"libstrip-1e" \
"C" \
"tmpdir/strip-1a-fat-s.o" \
] \
[list \
"Build strip-1f (libstrip-1a-fat-s.a)" \
"" \
"-O2 -flto $lto_fat" \
{ strip-1b-fat.c } \
{} \
"libstrip-1f" \
"C" \
"tmpdir/libstrip-1a-fat-s.a" \
] \
[list \
"Build strip-1g (strip-1b-fat-s.o)" \
"" \
"-O2 -flto $lto_fat" \
{ strip-1b-fat.c } \
{} \
"libstrip-1g" \
"C" \
"tmpdir/strip-1b-fat-s.o" \
] \
[list \
"Build strip-1h (libstrip-1b-fat-s.a)" \
"" \
"-O2 -flto $lto_fat" \
{ strip-1b-fat.c } \
{} \
"libstrip-1h" \
"C" \
"tmpdir/libstrip-1b-fat-s.a" \
] \
]

1
ld/testsuite/ld-plugin/strip-1a-fat.c Normal file
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@@ -0,0 +1 @@
#include "strip-1a.c"

6
ld/testsuite/ld-plugin/strip-1a-fat.rd Normal file
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@@ -0,0 +1,6 @@
#failif
#...
Section Headers:
#...
\[[ 0-9]+\] \.gnu.lto_.*
#...

4
ld/testsuite/ld-plugin/strip-1a.c Normal file
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@@ -0,0 +1,4 @@
extern void foo2(void);
extern void foo3(void);
void foo1(void) { foo3(); }
int main(void) { foo2(); }

1
ld/testsuite/ld-plugin/strip-1b-fat.c Normal file
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@@ -0,0 +1 @@
#include "strip-1b.c"

5
ld/testsuite/ld-plugin/strip-1b-fat.rd Normal file
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@@ -0,0 +1,5 @@
#...
Section Headers:
#...
\[[ 0-9]+\] \.gnu.lto_.*
#pass

3
ld/testsuite/ld-plugin/strip-1b.c Normal file
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@@ -0,0 +1,3 @@
extern void foo1(void);
void foo2(void) { foo1(); }
void foo3(void) {}

9
ld/testsuite/lib/ld-lib.exp
View File

@@ -860,14 +860,15 @@ proc run_ld_link_exec_tests { ldtests args } {
}
# List contains test-items with 3 items followed by 2 lists, one item and
# one optional item:
# 2 optional items:
# 0:name
# 1:ld or ar options
# 1:leading ld or ar options
# 2:compile options
# 3:filenames of source files
# 4:action and options.
# 5:name of output file
# 6:language (optional)
# 7:trailing ld options (optional), placed after object files
#
# Actions:
# objdump: Apply objdump options on result. Compare with regex (last arg).
@@ -899,6 +900,7 @@ proc run_cc_link_tests { ldtests } {
set actions [lindex $testitem 4]
set binfile tmpdir/[lindex $testitem 5]
set lang [lindex $testitem 6]
set trailing_ldflags [lindex $testitem 7]
set objfiles {}
set is_unresolved 0
set failed 0
@@ -927,6 +929,7 @@ proc run_cc_link_tests { ldtests } {
#verbose -log "actions is $actions"
#verbose -log "binfile is $binfile"
#verbose -log "lang is $lang"
#verbose -log "trailing_ldflags is $trailing_ldflags"
foreach actionlist $actions {
set action [lindex $actionlist 0]
@@ -1006,7 +1009,7 @@ proc run_cc_link_tests { ldtests } {
untested $testname
continue
}
ld_link $cc_cmd $binfile "-L$srcdir/$subdir $ldflags $objfiles"
ld_link $cc_cmd $binfile "-L$srcdir/$subdir $ldflags $objfiles $trailing_ldflags"
set ld_output "$exec_output"
if { $check_ld(source) == "regexp" } then {