Commit ba0509dc authored by Remi Bernon's avatar Remi Bernon Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarRemi Bernon <rbernon@codeweavers.com>
Acked-by: default avatarJiri 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e71e19a9

tools/perf/util/symbol-elf.c

+77 −3
Original line number Diff line number Diff line
@@ -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;