[PATCH] perf map: Do not display load warning for maps without dso

[Jiri Olsa <jolsa@redhat.com>]

hi,
I get unnecessary warnings from map__load about "[stack]" maps,
saying dso cannot be loaded.

Attached patch avoids this warning for maps that are
not backed-up by dso.

I was wondering if we want to treat stack/heaps/vdso maps
the same way or if there's something special about vdso
in this regard. Because there could be another fix with
setting all stack/heaps/vdso maps as loaded, which
is probably little more nicer.

thanks,
jirka

---
When report command proceses adress hits, it tries to resolve
them in to the symbol names. This is not possible for stack
and heap memory maps, because they are not backed-up by any
binary or dso.

This patch avoids the warning "Failed to open..." inside the
map__load function for stack and heap maps.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
 tools/perf/util/map.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index a16ecab..ac5fb40 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -18,6 +18,14 @@ static inline int is_anon_memory(const char *filename)
 	return strcmp(filename, "//anon") == 0;
 }
 
+static inline int is_no_dso_memory(struct map *self)
+{
+	const char *name = self->dso->long_name;
+
+	return (!strcmp(name, "[stack]") ||
+		!strcmp(name, "[heap]"));
+}
+
 void map__init(struct map *self, enum map_type type,
 	       u64 start, u64 end, u64 pgoff, struct dso *dso)
 {
@@ -108,6 +116,13 @@ int map__load(struct map *self, symbol_filter_t filter)
 
 	nr = dso__load(self->dso, self, filter);
 	if (nr < 0) {
+		/*
+		 * Do not print warning for maps that cannot
+		 * be loaded anyway.
+		 */
+		if (is_no_dso_memory(self))
+			return -1;
+
 		if (self->dso->has_build_id) {
 			char sbuild_id[BUILD_ID_SIZE * 2 + 1];
 
-- 
1.7.1