[tip:perf/core] perf script: Switch from perf.data' s kallsyms to perf's symbol resolver

[tip:perf/core] perf script: Switch from perf.data' s kallsyms to perf's symbol resolver

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  ccb3a8294a7d346257b526702eabcb2faeb721ac
Gitweb:     http://git.kernel.org/tip/ccb3a8294a7d346257b526702eabcb2faeb721ac
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Wed, 22 Jul 2015 16:43:37 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 23 Jul 2015 22:51:07 -0300

perf script: Switch from perf.data's kallsyms to perf's symbol resolver

We were storing a copy of kallsyms inside perf.data file so that we
could resolve kernel addresses to function (start, name, mod) tuples,
but that can be achieved using the symbol resolving routines we have
in symbols.c, and that are used elsewhere in tools/perf.

So, do just like 'perf trace' did and ask libtraceevent to use perf's
symbol resolution routines.

The next step is to just skip whatever kallsyms data is embedded in
older perf.data files and finally to stop storing kallsyms in the perf
data file, as the 20-bytes build-id stored in perf.data's header is
enough to find out the right symtab (be it ELF, kcore, kallsyms, etc) to
use.

Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-d0rtb8tk9j72pz0ehw5fnp24@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-script.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 24809787..2777c64 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1830,6 +1830,13 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 	else
 		symbol_conf.use_callchain = false;
 
+	if (pevent_set_function_resolver(session->tevent.pevent,
+					 machine__resolve_kernel_addr,
+					 &session->machines.host) < 0) {
+		pr_err("%s: failed to set libtraceevent function resolver\n", __func__);
+		return -1;
+	}
+
 	if (generate_script_lang) {
 		struct stat perf_stat;
 		int input;