perf dso: Use libbfd to read build_id and .gnu_debuglink section

Wine generates PE binaries for most of its modules and perf is unable to
parse these files to get build_id or .gnu_debuglink section.

Using libbfd when available, instead of libelf, makes it possible to
resolve debug file location regardless of the dso binary format.

Committer notes:

Made the filename__read_build_id() variant that uses abfd->build_id
depend on the feature test that defines HAVE_LIBBFD_BUILDID_SUPPORT, to
get this to continue building with older libbfd/binutils.

Signed-off-by: Remi Bernon <rbernon@codeweavers.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jacek Caban <jacek@codeweavers.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200821165238.1340315-1-rbernon@codeweavers.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Remi Bernon 2020-08-21 18:52:36 +02:00 committed by Arnaldo Carvalho de Melo
parent e71e19a9ea
commit ba0509dcb7

View File

@ -50,6 +50,10 @@ typedef Elf64_Nhdr GElf_Nhdr;
#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
#endif
#ifdef HAVE_LIBBFD_SUPPORT
#define PACKAGE 'perf'
#include <bfd.h>
#else
#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
extern char *cplus_demangle(const char *, int);
@ -65,9 +69,7 @@ static inline char *bfd_demangle(void __maybe_unused *v,
{
return NULL;
}
#else
#define PACKAGE 'perf'
#include <bfd.h>
#endif
#endif
#endif
@ -530,6 +532,36 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size)
return err;
}
#ifdef HAVE_LIBBFD_BUILDID_SUPPORT
int filename__read_build_id(const char *filename, void *bf, size_t size)
{
int err = -1;
bfd *abfd;
abfd = bfd_openr(filename, NULL);
if (!abfd)
return -1;
if (!bfd_check_format(abfd, bfd_object)) {
pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
goto out_close;
}
if (!abfd->build_id || abfd->build_id->size > size)
goto out_close;
memcpy(bf, abfd->build_id->data, abfd->build_id->size);
memset(bf + abfd->build_id->size, 0, size - abfd->build_id->size);
err = abfd->build_id->size;
out_close:
bfd_close(abfd);
return err;
}
#else // HAVE_LIBBFD_BUILDID_SUPPORT
int filename__read_build_id(const char *filename, void *bf, size_t size)
{
int fd, err = -1;
@ -557,6 +589,8 @@ int filename__read_build_id(const char *filename, void *bf, size_t size)
return err;
}
#endif // HAVE_LIBBFD_BUILDID_SUPPORT
int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
{
int fd, err = -1;
@ -608,6 +642,44 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
return err;
}
#ifdef HAVE_LIBBFD_SUPPORT
int filename__read_debuglink(const char *filename, char *debuglink,
size_t size)
{
int err = -1;
asection *section;
bfd *abfd;
abfd = bfd_openr(filename, NULL);
if (!abfd)
return -1;
if (!bfd_check_format(abfd, bfd_object)) {
pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
goto out_close;
}
section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
if (!section)
goto out_close;
if (section->size > size)
goto out_close;
if (!bfd_get_section_contents(abfd, section, debuglink, 0,
section->size))
goto out_close;
err = 0;
out_close:
bfd_close(abfd);
return err;
}
#else
int filename__read_debuglink(const char *filename, char *debuglink,
size_t size)
{
@ -660,6 +732,8 @@ int filename__read_debuglink(const char *filename, char *debuglink,
return err;
}
#endif
static int dso__swap_init(struct dso *dso, unsigned char eidata)
{
static unsigned int const endian = 1;