fix PR symtab/15597

This patch fixes gdb PR symtab/15597.

The bug is that the .gnu_debugaltlink section includes the build-id of
the alt file, but gdb does not use it.

This patch fixes the problem by changing gdb to do what it ought to
always have done: verify the build id of the file found using the
filename in .gnu_debugaltlink; and if that does not match, try to find
the correct debug file using the build-id and debug-file-directory.

This patch touches BFD.  Previously, gdb had its own code for parsing
.gnu_debugaltlink; I changed it to use the BFD functions after those
were introduced.  However, the BFD functions are incorrect -- they
assume that .gnu_debugaltlink is formatted like .gnu_debuglink.
However, it it is not.  Instead, it consists of a file name followed
by the build-id -- no alignment, and the build-id is not a CRC.

Fixing this properly is a bit of a pain.  But, because
separate_alt_debug_file_exists just has a FIXME for the build-id case,
I did not fix it properly.  Instead I introduced a hack.  This leaves
BFD working just as well as it did before my patch.

I'm willing to do something better here but I could use some guidance
as to what.  It seems that the build-id code in BFD is largely punted
on.

FWIW gdb is the only user of bfd_get_alt_debug_link_info outside of
BFD itself.

I moved the build-id logic out of elfread.c and into a new file.
This seemed cleanest to me.

Writing a test case was a bit of a pain.  I added a couple new
features to the DWARF assembler to handle this.

Built and regtested on x86-64 Fedora 18.

	* bfd-in2.h: Rebuild.
	* opncls.c (bfd_get_alt_debug_link_info): Add buildid_len
	parameter.  Change type of buildid_out.  Update.
	(get_alt_debug_link_info_shim): New function.
	(bfd_follow_gnu_debuglink): Use it.

	* Makefile.in (SFILES): Add build-id.c.
	(HFILES_NO_SRCDIR): Add build-id.h.
	* build-id.c: New file, largely from elfread.c.  Modified
	most functions.
	* build-id.h: New file.
	* dwarf2read.c (dwarf2_get_dwz_file): Update for change to
	bfd_get_alt_debug_link_info.  Verify dwz file's build-id.
	Search for dwz file using build-id.
	* elfread.c (build_id_bfd_get, build_id_verify)
	(build_id_to_debug_filename, find_separate_debug_file): Remove.

	* gdb.dwarf2/dwzbuildid.exp: New file.
	* lib/dwarf.exp (Dwarf::_section): Add "flags" and "type"
	parameters.
	(Dwarf::_defer_output): Change "section" parameter to
	"section_spec"; update.
	(Dwarf::gnu_debugaltlink, Dwarf::_note, Dwarf::build_id): New
	procs.
This commit is contained in:
Tom Tromey 2013-10-08 19:56:15 +00:00
parent 5bb7df2edf
commit dc294be54c
12 changed files with 530 additions and 155 deletions

View File

@ -1,3 +1,11 @@
2013-10-08 Tom Tromey <tromey@redhat.com>
* bfd-in2.h: Rebuild.
* opncls.c (bfd_get_alt_debug_link_info): Add buildid_len
parameter. Change type of buildid_out. Update.
(get_alt_debug_link_info_shim): New function.
(bfd_follow_gnu_debuglink): Use it.
2013-10-08 Andreas Schwab <schwab@suse.de>
* elf32-m68k.c (elf_m68k_size_dynamic_sections): Add DT_DEBUG also

View File

@ -1067,7 +1067,8 @@ unsigned long bfd_calc_gnu_debuglink_crc32
char *bfd_get_debug_link_info (bfd *abfd, unsigned long *crc32_out);
char *bfd_get_alt_debug_link_info (bfd *abfd, unsigned long *crc32_out);
char *bfd_get_alt_debug_link_info (bfd * abfd, size_t *buildid_len,
bfd_byte **buildid_out);
char *bfd_follow_gnu_debuglink (bfd *abfd, const char *dir);

View File

@ -1194,18 +1194,21 @@ FUNCTION
bfd_get_alt_debug_link_info
SYNOPSIS
char *bfd_get_alt_debug_link_info (bfd *abfd, unsigned long *crc32_out);
char *bfd_get_alt_debug_link_info (bfd * abfd, size_t *buildid_len,
bfd_byte **buildid_out);
DESCRIPTION
Fetch the filename and BuildID value for any alternate debuginfo
associated with @var{abfd}. Return NULL if no such info found,
otherwise return filename and update @var{buildid_out}. The
returned filename is allocated with @code{malloc}; freeing it
is the responsibility of the caller.
otherwise return filename and update @var{buildid_len} and
@var{buildid_out}. The returned filename and build_id are
allocated with @code{malloc}; freeing them is the
responsibility of the caller.
*/
char *
bfd_get_alt_debug_link_info (bfd * abfd, unsigned long * buildid_out)
bfd_get_alt_debug_link_info (bfd * abfd, size_t *buildid_len,
bfd_byte **buildid_out)
{
asection *sect;
bfd_byte *contents;
@ -1213,6 +1216,7 @@ bfd_get_alt_debug_link_info (bfd * abfd, unsigned long * buildid_out)
char *name;
BFD_ASSERT (abfd);
BFD_ASSERT (buildid_len);
BFD_ASSERT (buildid_out);
sect = bfd_get_section_by_name (abfd, GNU_DEBUGALTLINK);
@ -1227,12 +1231,13 @@ bfd_get_alt_debug_link_info (bfd * abfd, unsigned long * buildid_out)
return NULL;
}
/* BuildID value is stored after the filename, aligned up to 4 bytes. */
/* BuildID value is stored after the filename. */
name = (char *) contents;
buildid_offset = strlen (name) + 1;
buildid_offset = (buildid_offset + 3) & ~3;
* buildid_out = bfd_get_32 (abfd, contents + buildid_offset);
*buildid_len = bfd_get_section_size (sect) - buildid_offset;
*buildid_out = bfd_malloc (*buildid_len);
memcpy (*buildid_out, contents + buildid_offset, *buildid_len);
return name;
}
@ -1466,6 +1471,24 @@ bfd_follow_gnu_debuglink (bfd *abfd, const char *dir)
separate_debug_file_exists);
}
/* Helper for bfd_follow_gnu_debugaltlink. It just pretends to return
a CRC. .gnu_debugaltlink supplies a build-id, which is different,
but this is ok because separate_alt_debug_file_exists ignores the
CRC anyway. */
static char *
get_alt_debug_link_info_shim (bfd * abfd, unsigned long *crc32_out)
{
size_t len;
bfd_byte *buildid = NULL;
char *result = bfd_get_alt_debug_link_info (abfd, &len, &buildid);
*crc32_out = 0;
free (buildid);
return result;
}
/*
FUNCTION
bfd_follow_gnu_debugaltlink
@ -1496,7 +1519,7 @@ char *
bfd_follow_gnu_debugaltlink (bfd *abfd, const char *dir)
{
return find_separate_debug_file (abfd, dir,
bfd_get_alt_debug_link_info,
get_alt_debug_link_info_shim,
separate_alt_debug_file_exists);
}

View File

@ -1,3 +1,16 @@
2013-10-08 Tom Tromey <tromey@redhat.com>
* Makefile.in (SFILES): Add build-id.c.
(HFILES_NO_SRCDIR): Add build-id.h.
* build-id.c: New file, largely from elfread.c. Modified
most functions.
* build-id.h: New file.
* dwarf2read.c (dwarf2_get_dwz_file): Update for change to
bfd_get_alt_debug_link_info. Verify dwz file's build-id.
Search for dwz file using build-id.
* elfread.c (build_id_bfd_get, build_id_verify)
(build_id_to_debug_filename, find_separate_debug_file): Remove.
2013-10-08 Joel Brobecker <brobecker@adacore.com>
* ada-lang.c (compare_names_with_case): Renamed from

View File

@ -717,7 +717,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
bfd-target.c \
block.c blockframe.c \
breakpoint.c break-catch-sig.c break-catch-throw.c \
buildsym.c \
build-id.c buildsym.c \
c-exp.y c-lang.c c-typeprint.c c-valprint.c \
charset.c cleanups.c cli-out.c coffread.c coff-pe-read.c \
complaints.c completer.c continuations.c corefile.c corelow.c \
@ -814,7 +814,8 @@ tui/tui-file.h tui/tui-command.h tui/tui-disasm.h tui/tui-wingeneral.h \
tui/tui-windata.h tui/tui-data.h tui/tui-win.h tui/tui-stack.h \
tui/tui-winsource.h tui/tui-regs.h tui/tui-io.h tui/tui-layout.h \
tui/tui-source.h sol2-tdep.h gregset.h sh-tdep.h sh64-tdep.h \
expression.h score-tdep.h gdb_select.h ser-tcp.h buildsym.h valprint.h \
expression.h score-tdep.h gdb_select.h ser-tcp.h \
build-id.h buildsym.h valprint.h \
typeprint.h mi/mi-getopt.h mi/mi-parse.h mi/mi-console.h \
mi/mi-out.h mi/mi-main.h mi/mi-common.h mi/mi-cmds.h linux-nat.h \
complaints.h gdb_proc_service.h gdb_regex.h xtensa-tdep.h inf-loop.h \
@ -911,7 +912,8 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
event-loop.o event-top.o inf-loop.o completer.o \
gdbarch.o arch-utils.o gdbtypes.o gdb_bfd.o gdb_obstack.o \
osabi.o copying.o \
memattr.o mem-break.o target.o parse.o language.o buildsym.o \
memattr.o mem-break.o target.o parse.o language.o \
build-id.o buildsym.o \
findcmd.o \
std-regs.o \
signals.o \

168
gdb/build-id.c Normal file
View File

@ -0,0 +1,168 @@
/* build-id-related functions.
Copyright (C) 1991-2013 Free Software Foundation, Inc.
This file is part of GDB.
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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "bfd.h"
#include "elf-bfd.h"
#include "gdb_bfd.h"
#include "build-id.h"
#include "gdb_string.h"
#include "gdb_vecs.h"
#include "symfile.h"
#include "objfiles.h"
#include "filenames.h"
/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
static const struct elf_build_id *
build_id_bfd_get (bfd *abfd)
{
if (!bfd_check_format (abfd, bfd_object)
|| bfd_get_flavour (abfd) != bfd_target_elf_flavour
/* Although this is ELF_specific, it is safe to do in generic
code because it does not rely on any ELF-specific symbols at
link time, and if the ELF code is not available in BFD, then
ABFD will not have the ELF flavour. */
|| elf_tdata (abfd)->build_id == NULL)
return NULL;
return elf_tdata (abfd)->build_id;
}
/* See build-id.h. */
int
build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check)
{
const struct elf_build_id *found;
int retval = 0;
found = build_id_bfd_get (abfd);
if (found == NULL)
warning (_("File \"%s\" has no build-id, file skipped"),
bfd_get_filename (abfd));
else if (found->size != check_len
|| memcmp (found->data, check, found->size) != 0)
warning (_("File \"%s\" has a different build-id, file skipped"),
bfd_get_filename (abfd));
else
retval = 1;
return retval;
}
/* See build-id.h. */
bfd *
build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id)
{
char *link, *debugdir;
VEC (char_ptr) *debugdir_vec;
struct cleanup *back_to;
int ix;
bfd *abfd = NULL;
/* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
+ 2 * build_id_len + (sizeof ".debug" - 1) + 1);
/* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
cause "/.build-id/..." lookups. */
debugdir_vec = dirnames_to_char_ptr_vec (debug_file_directory);
back_to = make_cleanup_free_char_ptr_vec (debugdir_vec);
for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix)
{
size_t debugdir_len = strlen (debugdir);
const gdb_byte *data = build_id;
size_t size = build_id_len;
char *s;
char *filename = NULL;
memcpy (link, debugdir, debugdir_len);
s = &link[debugdir_len];
s += sprintf (s, "/.build-id/");
if (size > 0)
{
size--;
s += sprintf (s, "%02x", (unsigned) *data++);
}
if (size > 0)
*s++ = '/';
while (size-- > 0)
s += sprintf (s, "%02x", (unsigned) *data++);
strcpy (s, ".debug");
/* lrealpath() is expensive even for the usually non-existent files. */
if (access (link, F_OK) == 0)
filename = lrealpath (link);
if (filename == NULL)
continue;
/* We expect to be silent on the non-existing files. */
abfd = gdb_bfd_open_maybe_remote (filename);
if (abfd == NULL)
continue;
if (build_id_verify (abfd, build_id_len, build_id))
break;
gdb_bfd_unref (abfd);
abfd = NULL;
}
do_cleanups (back_to);
return abfd;
}
/* See build-id.h. */
char *
find_separate_debug_file_by_buildid (struct objfile *objfile)
{
const struct elf_build_id *build_id;
build_id = build_id_bfd_get (objfile->obfd);
if (build_id != NULL)
{
bfd *abfd;
abfd = build_id_to_debug_bfd (build_id->size, build_id->data);
/* Prevent looping on a stripped .debug file. */
if (abfd != NULL
&& filename_cmp (bfd_get_filename (abfd),
objfile_name (objfile)) == 0)
{
warning (_("\"%s\": separate debug info file has no debug info"),
bfd_get_filename (abfd));
gdb_bfd_unref (abfd);
}
else if (abfd != NULL)
{
char *result = xstrdup (bfd_get_filename (abfd));
gdb_bfd_unref (abfd);
return result;
}
}
return NULL;
}

44
gdb/build-id.h Normal file
View File

@ -0,0 +1,44 @@
/* build-id-related functions.
Copyright (C) 1991-2013 Free Software Foundation, Inc.
This file is part of GDB.
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, see <http://www.gnu.org/licenses/>. */
#ifndef BUILD_ID_H
#define BUILD_ID_H
/* Return true if ABFD has NT_GNU_BUILD_ID matching the CHECK value.
Otherwise, issue a warning and return false. */
extern int build_id_verify (bfd *abfd,
size_t check_len, const bfd_byte *check);
/* Find and open a BFD given a build-id. If no BFD can be found,
return NULL. The returned reference to the BFD must be released by
the caller. */
extern bfd *build_id_to_debug_bfd (size_t build_id_len,
const bfd_byte *build_id);
/* Find the separate debug file for OBJFILE, by using the build-id
associated with OBJFILE's BFD. If successful, returns a malloc'd
file name for the separate debug file. The caller must free this.
Otherwise, returns NULL. */
extern char *find_separate_debug_file_by_buildid (struct objfile *objfile);
#endif /* BUILD_ID_H */

View File

@ -69,6 +69,7 @@
#include "f-lang.h"
#include "source.h"
#include "filestuff.h"
#include "build-id.h"
#include <fcntl.h>
#include "gdb_string.h"
@ -2364,14 +2365,15 @@ dwarf2_get_dwz_file (void)
struct cleanup *cleanup;
const char *filename;
struct dwz_file *result;
unsigned long buildid;
size_t buildid_len;
bfd_byte *buildid;
if (dwarf2_per_objfile->dwz_file != NULL)
return dwarf2_per_objfile->dwz_file;
bfd_set_error (bfd_error_no_error);
data = bfd_get_alt_debug_link_info (dwarf2_per_objfile->objfile->obfd,
&buildid);
&buildid_len, &buildid);
if (data == NULL)
{
if (bfd_get_error () == bfd_error_no_error)
@ -2380,6 +2382,7 @@ dwarf2_get_dwz_file (void)
bfd_errmsg (bfd_get_error ()));
}
cleanup = make_cleanup (xfree, data);
make_cleanup (xfree, buildid);
filename = (const char *) data;
if (!IS_ABSOLUTE_PATH (filename))
@ -2396,20 +2399,25 @@ dwarf2_get_dwz_file (void)
filename = rel;
}
/* The format is just a NUL-terminated file name, followed by the
build-id. For now, though, we ignore the build-id. */
/* First try the file name given in the section. If that doesn't
work, try to use the build-id instead. */
dwz_bfd = gdb_bfd_open (filename, gnutarget, -1);
if (dwz_bfd == NULL)
error (_("could not read '%s': %s"), filename,
bfd_errmsg (bfd_get_error ()));
if (!bfd_check_format (dwz_bfd, bfd_object))
if (dwz_bfd != NULL)
{
gdb_bfd_unref (dwz_bfd);
error (_("file '%s' was not usable: %s"), filename,
bfd_errmsg (bfd_get_error ()));
if (!build_id_verify (dwz_bfd, buildid_len, buildid))
{
gdb_bfd_unref (dwz_bfd);
dwz_bfd = NULL;
}
}
if (dwz_bfd == NULL)
dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid);
if (dwz_bfd == NULL)
error (_("could not find '.gnu_debugaltlink' file for %s"),
objfile_name (dwarf2_per_objfile->objfile));
result = OBSTACK_ZALLOC (&dwarf2_per_objfile->objfile->objfile_obstack,
struct dwz_file);
result->dwz_bfd = dwz_bfd;

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@ -45,6 +45,7 @@
#include "regcache.h"
#include "bcache.h"
#include "gdb_bfd.h"
#include "build-id.h"
extern void _initialize_elfread (void);
@ -1087,131 +1088,6 @@ elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
update_breakpoint_locations (b, sals, sals_end);
}
/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
static const struct elf_build_id *
build_id_bfd_get (bfd *abfd)
{
if (!bfd_check_format (abfd, bfd_object)
|| bfd_get_flavour (abfd) != bfd_target_elf_flavour
|| elf_tdata (abfd)->build_id == NULL)
return NULL;
return elf_tdata (abfd)->build_id;
}
/* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
static int
build_id_verify (const char *filename, const struct elf_build_id *check)
{
bfd *abfd;
const struct elf_build_id *found;
int retval = 0;
/* We expect to be silent on the non-existing files. */
abfd = gdb_bfd_open_maybe_remote (filename);
if (abfd == NULL)
return 0;
found = build_id_bfd_get (abfd);
if (found == NULL)
warning (_("File \"%s\" has no build-id, file skipped"), filename);
else if (found->size != check->size
|| memcmp (found->data, check->data, found->size) != 0)
warning (_("File \"%s\" has a different build-id, file skipped"),
filename);
else
retval = 1;
gdb_bfd_unref (abfd);
return retval;
}
static char *
build_id_to_debug_filename (const struct elf_build_id *build_id)
{
char *link, *debugdir, *retval = NULL;
VEC (char_ptr) *debugdir_vec;
struct cleanup *back_to;
int ix;
/* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
+ 2 * build_id->size + (sizeof ".debug" - 1) + 1);
/* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
cause "/.build-id/..." lookups. */
debugdir_vec = dirnames_to_char_ptr_vec (debug_file_directory);
back_to = make_cleanup_free_char_ptr_vec (debugdir_vec);
for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix)
{
size_t debugdir_len = strlen (debugdir);
const gdb_byte *data = build_id->data;
size_t size = build_id->size;
char *s;
memcpy (link, debugdir, debugdir_len);
s = &link[debugdir_len];
s += sprintf (s, "/.build-id/");
if (size > 0)
{
size--;
s += sprintf (s, "%02x", (unsigned) *data++);
}
if (size > 0)
*s++ = '/';
while (size-- > 0)
s += sprintf (s, "%02x", (unsigned) *data++);
strcpy (s, ".debug");
/* lrealpath() is expensive even for the usually non-existent files. */
if (access (link, F_OK) == 0)
retval = lrealpath (link);
if (retval != NULL && !build_id_verify (retval, build_id))
{
xfree (retval);
retval = NULL;
}
if (retval != NULL)
break;
}
do_cleanups (back_to);
return retval;
}
static char *
find_separate_debug_file_by_buildid (struct objfile *objfile)
{
const struct elf_build_id *build_id;
build_id = build_id_bfd_get (objfile->obfd);
if (build_id != NULL)
{
char *build_id_name;
build_id_name = build_id_to_debug_filename (build_id);
/* Prevent looping on a stripped .debug file. */
if (build_id_name != NULL
&& filename_cmp (build_id_name, objfile_name (objfile)) == 0)
{
warning (_("\"%s\": separate debug info file has no debug info"),
build_id_name);
xfree (build_id_name);
}
else if (build_id_name != NULL)
return build_id_name;
}
return NULL;
}
/* Scan and build partial symbols for a symbol file.
We have been initialized by a call to elf_symfile_init, which
currently does nothing.

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@ -1,3 +1,13 @@
2013-10-08 Tom Tromey <tromey@redhat.com>
* gdb.dwarf2/dwzbuildid.exp: New file.
* lib/dwarf.exp (Dwarf::_section): Add "flags" and "type"
parameters.
(Dwarf::_defer_output): Change "section" parameter to
"section_spec"; update.
(Dwarf::gnu_debugaltlink, Dwarf::_note, Dwarf::build_id): New
procs.
2013-10-08 Joel Brobecker <brobecker@adacore.com>
* gdb.ada/mi_catch_ex.exp: Make "mi_execute_to" test names unique.

View File

@ -0,0 +1,170 @@
# Copyright 2013 Free Software Foundation, Inc.
# 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, see <http://www.gnu.org/licenses/>.
load_lib dwarf.exp
# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
return 0
}
# No remote host testing either.
if {[is_remote host]} {
return 0
}
# Lots of source files since we test a few cases and make new files
# for each.
# The tests are:
# ok - the main file refers to a dwz and the buildids match
# mismatch - the buildids do not match
# fallback - the buildids do not match but a match is found via buildid
standard_testfile main.c \
dwzbuildid-ok-base.S dwzbuildid-ok-sep.S \
dwzbuildid-mismatch-base.S dwzbuildid-mismatch-sep.S \
dwzbuildid-fallback-base.S dwzbuildid-fallback-sep.S \
dwzbuildid-fallback-ok.S
# Write some assembly that just has a .gnu_debugaltlink section.
proc write_just_debugaltlink {filename dwzname buildid} {
set asm_file [standard_output_file $filename]
Dwarf::assemble $asm_file {
upvar dwzname dwzname
upvar buildid buildid
gnu_debugaltlink $dwzname $buildid
# Only the DWARF reader checks .gnu_debugaltlink, so make sure
# there is a bit of DWARF in here.
cu {} {
compile_unit {{language @DW_LANG_C}} {
}
}
}
}
# Write some DWARF that also sets the buildid.
proc write_dwarf_file {filename buildid {value 99}} {
set asm_file [standard_output_file $filename]
Dwarf::assemble $asm_file {
declare_labels partial_label double_label int_label int_label2
upvar buildid buildid
upvar value value
build_id $buildid
cu {} {
compile_unit {{language @DW_LANG_C}} {
int_label2: base_type {
{name int}
{byte_size 4 sdata}
{encoding @DW_ATE_signed}
}
constant {
{name the_int}
{type :$int_label2}
{const_value $value data1}
}
}
}
}
}
if { [gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile}1.o \
object {nodebug}] != "" } {
return -1
}
# The values don't really matter, just whether they are equal.
set ok_prefix 01
set ok_suffix 0203040506
set ok_suffix2 02030405ff
set ok_buildid ${ok_prefix}${ok_suffix}
set ok_buildid2 ${ok_prefix}${ok_suffix2}
set bad_buildid ffffffffffff
set outdir [standard_output_file {}]
set basedir $outdir/.build-id
file mkdir $basedir $basedir/$ok_prefix
# Test where the separate debuginfo's buildid matches.
write_just_debugaltlink $srcfile2 ${binfile}3.o $ok_buildid
write_dwarf_file $srcfile3 $ok_buildid
# Test where the separate debuginfo's buildid does not match.
write_just_debugaltlink $srcfile4 ${binfile}5.o $ok_buildid
write_dwarf_file $srcfile5 $bad_buildid
# Test where the separate debuginfo's buildid does not match, but then
# we find a match in the .build-id directory.
write_just_debugaltlink $srcfile6 ${binfile}7.o $ok_buildid2
# Use 77 as the value so that if we load the bad debuginfo, we will
# see the wrong result.
write_dwarf_file $srcfile7 $bad_buildid 77
write_dwarf_file $srcfile8 $ok_buildid2
# Compile everything.
for {set i 2} {$i <= 8} {incr i} {
if {[gdb_compile [standard_output_file [set srcfile$i]] \
${binfile}$i.o object nodebug] != ""} {
return -1
}
}
# Copy a file into the .build-id place for the "fallback" test.
file copy -force -- ${binfile}8.o $basedir/$ok_prefix/$ok_suffix2.debug
# Link the executables.
if {[gdb_compile [list ${binfile}1.o ${binfile}2.o] ${binfile}-ok \
executable {}] != ""} {
return -1
}
if {[gdb_compile [list ${binfile}1.o ${binfile}4.o] ${binfile}-mismatch \
executable {}] != ""} {
return -1
}
if {[gdb_compile [list ${binfile}1.o ${binfile}6.o] ${binfile}-fallback \
executable {}] != ""} {
return -1
}
foreach testname {ok mismatch fallback} {
with_test_prefix $testname {
gdb_exit
gdb_start
gdb_reinitialize_dir $srcdir/$subdir
gdb_test_no_output "set debug-file-directory $outdir"
gdb_load ${binfile}-${testname}
if {[runto_main]} {
if {$testname == "mismatch"} {
gdb_test "print the_int" \
"No symbol table is loaded.*"
} else {
gdb_test "print the_int" " = 99"
}
}
}
}

View File

@ -523,20 +523,27 @@ namespace eval Dwarf {
}
}
proc _section {name} {
_emit " .section $name"
proc _section {name {flags ""} {type ""}} {
if {$flags == "" && $type == ""} {
_emit " .section $name"
} elseif {$type == ""} {
_emit " .section $name, \"$flags\""
} else {
_emit " .section $name, \"$flags\", %$type"
}
}
proc _defer_output {section body} {
# SECTION_SPEC is a list of arguments to _section.
proc _defer_output {section_spec body} {
variable _defer
variable _deferred_output
set old_defer $_defer
set _defer $section
set _defer [lindex $section_spec 0]
if {![info exists _deferred_output($_defer)]} {
set _deferred_output($_defer) ""
_section $section
eval _section $section_spec
}
uplevel $body
@ -948,6 +955,51 @@ namespace eval Dwarf {
unset the_array(_)
}
# Emit a .gnu_debugaltlink section with the given file name and
# build-id. The buildid should be represented as a hexadecimal
# string, like "ffeeddcc".
proc gnu_debugaltlink {filename buildid} {
_defer_output .gnu_debugaltlink {
_op .ascii [_quote $filename]
foreach {a b} [split $buildid {}] {
_op .byte 0x$a$b
}
}
}
proc _note {type name hexdata} {
set namelen [expr [string length $name] + 1]
# Name size.
_op .4byte $namelen
# Data size.
_op .4byte [expr [string length $hexdata] / 2]
# Type.
_op .4byte $type
# The name.
_op .ascii [_quote $name]
# Alignment.
set align 2
set total [expr {($namelen + (1 << $align) - 1) & (-1 << $align)}]
for {set i $namelen} {$i < $total} {incr i} {
_op .byte 0
}
# The data.
foreach {a b} [split $hexdata {}] {
_op .byte 0x$a$b
}
}
# Emit a note section holding the given build-id.
proc build_id {buildid} {
_defer_output {.note.gnu.build-id a note} {
# From elf/common.h.
set NT_GNU_BUILD_ID 3
_note $NT_GNU_BUILD_ID GNU $buildid
}
}
# The top-level interface to the DWARF assembler.
# FILENAME is the name of the file where the generated assembly
# code is written.