perf probe: Fix debuginfo__new() to enable build-id based debuginfo

Fix debuginfo__new() to set the build-id to dso before
dso__read_binary_type_filename() so that it can find
DSO_BINARY_TYPE__BUILDID_DEBUGINFO debuginfo correctly.

However, this may not change the result, because elfutils (libdwfl) has
its own debuginfo finder. With/without this patch, the perf probe
correctly find the debuginfo file.

This is just a failsafe and keep code's sanity (if you use
dso__read_binary_type_filename(), you must set the build-id to the dso.)
Reported-by: NThomas Richter <tmricht@linux.ibm.com>
Acked-by: NThomas Richter <tmricht@linux.ibm.com>
Signed-off-by: NMasami Hiramatsu <mhriamat@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stefan Liebler <stli@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Link: http://lore.kernel.org/lkml/162532651863.393143.11692691321219235810.stgit@devnote2Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/probe-finder.c

@@ -118,12 +118,17 @@ struct debuginfo *debuginfo__new(const char *path)
 	char buf[PATH_MAX], nil = '\0';
 	struct dso *dso;
 	struct debuginfo *dinfo = NULL;
+	struct build_id bid;
 
 	/* Try to open distro debuginfo files */
 	dso = dso__new(path);
 	if (!dso)
 		goto out;
 
+	/* Set the build id for DSO_BINARY_TYPE__BUILDID_DEBUGINFO */
+	if (is_regular_file(path) && filename__read_build_id(path, &bid) > 0)
+		dso__set_build_id(dso, &bid);
+
 	for (type = distro_dwarf_types;
 	     !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 	     type++) {