[tip:perf/core] perf symbols: Allow symbol alias when loading map for symbol name

[tip-bot for Namhyung Kim <tipbot@zytor.com>]

Commit-ID:  680d926a8cb08dd9cf173e2bb93d4a4477771949
Gitweb:     http://git.kernel.org/tip/680d926a8cb08dd9cf173e2bb93d4a4477771949
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Fri, 6 Mar 2015 16:31:27 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 12 Mar 2015 12:39:54 -0300

perf symbols: Allow symbol alias when loading map for symbol name

When perf probe tries to add a probe in a binary using symbol name, it
sometimes failed since some symbols were discard during loading dso.

When it resolves an address to symbol, it'd be better to have just one
symbol at given address.  But for finding address from symbol, it'd be
better to keep all names (including aliases).

So allow tools to state that they want to allow aliases via
symbol_conf.allow_aliases.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150306073127.6904.3232.stgit@localhost.localdomain
[ Original patch passwd allow_alias to many functions, use symbol_conf.allow_aliases instead ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-event.c | 1 +
 tools/perf/util/symbol-elf.c  | 3 ++-
 tools/perf/util/symbol.h      | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c379ea0..9feba0e 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -80,6 +80,7 @@ static int init_symbol_maps(bool user_only)
 	int ret;
 
 	symbol_conf.sort_by_name = true;
+	symbol_conf.allow_aliases = true;
 	ret = symbol__init(NULL);
 	if (ret < 0) {
 		pr_debug("Failed to init symbol map.\n");
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index ada1676..62742e4 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1048,7 +1048,8 @@ new_symbol:
 	 * For misannotated, zeroed, ASM function sizes.
 	 */
 	if (nr > 0) {
-		symbols__fixup_duplicate(&dso->symbols[map->type]);
+		if (!symbol_conf.allow_aliases)
+			symbols__fixup_duplicate(&dso->symbols[map->type]);
 		symbols__fixup_end(&dso->symbols[map->type]);
 		if (kmap) {
 			/*
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 1650dcb..efdaaa5 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -87,6 +87,7 @@ struct symbol_conf {
 			ignore_vmlinux_buildid,
 			show_kernel_path,
 			use_modules,
+			allow_aliases,
 			sort_by_name,
 			show_nr_samples,
 			show_total_period,