[PATCH 1/2] perf symbols: use .gnu_debuglink as gdb does

[PATCH 1/2] perf symbols: use .gnu_debuglink as gdb does

[Uwe Kleine-König]

As documented in the comment gdb looks for debug files not only relative
to the binary's directory, but also in .debug and /usr/lib/debug/.
Let perf do the same thing.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 tools/perf/util/dso.c | 49 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 39 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 774f6ec884d5..51d39f37cabd 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -45,21 +45,50 @@ int dso__read_binary_type_filename(const struct dso *dso,
 
 	switch (type) {
 	case DSO_BINARY_TYPE__DEBUGLINK: {
-		char *debuglink;
+		/* gdb interprets the content of the debuglink section as
+		 * path relative to
+		 *  - the binary's directory
+		 *  - .debug/ in the binary's directory
+		 *  - /usr/lib/debug
+		 *  and uses the first one that exists.
+		 */
+		char debuglink[512];
+		char *pathbase;
 
 		len = __symbol__join_symfs(filename, size, dso->long_name);
-		debuglink = filename + len;
-		while (debuglink != filename && *debuglink != '/')
-			debuglink--;
-		if (*debuglink == '/')
-			debuglink++;
+		if (!is_regular_file(filename)) {
+			ret = -1;
+			break;
+		}
 
-		ret = -1;
-		if (!is_regular_file(filename))
+		ret = filename__read_debuglink(filename,
+					       debuglink, sizeof(debuglink));
+		if (ret < 0)
+			break;
+
+		pathbase = filename + len;
+		while (pathbase != filename && *pathbase != '/')
+			pathbase--;
+		if (*pathbase == '/')
+			pathbase++;
+
+		snprintf(pathbase, size - (pathbase - filename),
+			 "%s", debuglink);
+		if (is_regular_file(filename))
+			break;
+
+		snprintf(pathbase, size - (pathbase - filename),
+			 ".debug/%s", debuglink);
+		if (is_regular_file(filename))
+			break;
+
+		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+		snprintf(filename + len, size - len, "%s", debuglink);
+
+		if (is_regular_file(filename))
 			break;
 
-		ret = filename__read_debuglink(filename, debuglink,
-					       size - (debuglink - filename));
+		ret = -1;
 		}
 		break;
 	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
-- 
2.8.1

[PATCH 2/2] perf probe: Add option --symfs

[Uwe Kleine-König]

perf probe makes use of debug symbols, so add --symfs as the other
commands have.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 tools/perf/builtin-probe.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index ee5b42173ba3..f82d9b453366 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -542,6 +542,8 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
 	OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel,
 		    "Enable kernel symbol demangling"),
 	OPT_BOOLEAN(0, "cache", &probe_conf.cache, "Manipulate probe cache"),
+	OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+		   "Look for files with symbols relative to this directory"),
 	OPT_END()
 	};
 	int ret;
-- 
2.8.1

Re: [PATCH 1/2] perf symbols: use .gnu_debuglink as gdb does

[Uwe Kleine-König]

On Thu, Jul 21, 2016 at 11:48:31AM +0200, Uwe Kleine-König wrote:
> As documented in the comment gdb looks for debug files not only relative
> to the binary's directory, but also in .debug and /usr/lib/debug/.
> Let perf do the same thing.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

ping.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Re: [PATCH 1/2] perf symbols: use .gnu_debuglink as gdb does

[Arnaldo Carvalho de Melo]

Em Thu, Jan 19, 2017 at 10:51:39AM +0100, Uwe Kleine-König escreveu:
> On Thu, Jul 21, 2016 at 11:48:31AM +0200, Uwe Kleine-König wrote:
> > As documented in the comment gdb looks for debug files not only relative
> > to the binary's directory, but also in .debug and /usr/lib/debug/.
> > Let perf do the same thing.
> > 
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> 
> ping.

Sorry, completely lost track of these two :-\

Applied 'perf probe --symfs' one, the other should be already dealt with
by another patch, this one:

t 9343e45bf6cc4a05f6e271e9f8d06bc87875c604
Author: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Date:   Tue Jan 17 15:50:35 2017 +0100

    perf unwind: Fix looking up dwarf unwind stack info

-----------

That is in tip/perf/core now.

- Arnaldo
 
> Best regards
> Uwe
> 
> -- 
> Pengutronix e.K.                           | Uwe Kleine-König            |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |