[RFC/PATCH 2/2] perf probe: Allow weak symbols to be probed

[Namhyung Kim <namhyung@kernel.org>]

It currently prevents adding probes in weak symbols.  But there're cases
that given name is an only weak symbol so that we cannot add probe.

  $ perf probe -x /usr/lib/libc.so.6 -a calloc
  Failed to find symbol calloc in /usr/lib/libc-2.21.so
    Error: Failed to add events.

  $ nm /usr/lib/libc.so.6 | grep calloc
  000000000007b1f0 t __calloc
  000000000007b1f0 T __libc_calloc
  000000000007b1f0 W calloc

This change will result in duplicate probes when strong and weak symbols
co-exist in a binary.  But I think it's not a big problem since probes
at the weak symbol will never be hit anyway.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/probe-event.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 1c570c2fa7cc..12b7d018106e 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2339,8 +2339,7 @@ static int find_probe_functions(struct map *map, char *name)
 	struct symbol *sym;
 
 	map__for_each_symbol_by_name(map, name, sym) {
-		if (sym->binding == STB_GLOBAL || sym->binding == STB_LOCAL)
-			found++;
+		found++;
 	}
 
 	return found;
@@ -2708,8 +2707,7 @@ static struct strfilter *available_func_filter;
 static int filter_available_functions(struct map *map __maybe_unused,
 				      struct symbol *sym)
 {
-	if ((sym->binding == STB_GLOBAL || sym->binding == STB_LOCAL) &&
-	    strfilter__compare(available_func_filter, sym->name))
+	if (strfilter__compare(available_func_filter, sym->name))
 		return 0;
 	return 1;
 }
-- 
2.3.1