perf probe: Fix error message for failing to find line range

With --lines option, if perf-probe fails to find the specified line, it
warns as "Debuginfo analysis failed." but this misleads user as the
debuginfo is broken.

Fix this message to "Specified source line(LINESPEC) is not found." so
that user can understand the error correctly.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/173099113381.2431889.16263147678401426107.stgit@mhiramat.roam.corp.google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/probe-event.c

@@ -1039,6 +1039,17 @@ static int _show_one_line(FILE *fp, int l, bool skip, bool show_num)
 	return rv;
 }
 
+static int sprint_line_description(char *sbuf, size_t size, struct line_range *lr)
+{
+	if (!lr->function)
+		return snprintf(sbuf, size, "file: %s, line: %d", lr->file, lr->start);
+
+	if (lr->file)
+		return snprintf(sbuf, size, "function: %s, file:%s, line: %d", lr->function, lr->file, lr->start);
+
+	return snprintf(sbuf, size, "function: %s, line:%d", lr->function, lr->start);
+}
+
 #define show_one_line_with_num(f,l)	_show_one_line(f,l,false,true)
 #define show_one_line(f,l)		_show_one_line(f,l,false,false)
 #define skip_one_line(f,l)		_show_one_line(f,l,true,false)
@@ -1071,14 +1082,17 @@ static int __show_line_range(struct line_range *lr, const char *module,
 		ret = get_alternative_line_range(dinfo, lr, module, user);
 		if (!ret)
 			ret = debuginfo__find_line_range(dinfo, lr);
+		else /* Ignore error, we just failed to find it. */
+			ret = -ENOENT;
 	}
 	if (dinfo->build_id) {
 		build_id__init(&bid, dinfo->build_id, BUILD_ID_SIZE);
 		build_id__sprintf(&bid, sbuild_id);
 	}
 	debuginfo__delete(dinfo);
 	if (ret == 0 || ret == -ENOENT) {
-		pr_warning("Specified source line is not found.\n");
+		sprint_line_description(sbuf, sizeof(sbuf), lr);
+		pr_warning("Specified source line(%s) is not found.\n", sbuf);
 		return -ENOENT;
 	} else if (ret < 0) {
 		pr_warning("Debuginfo analysis failed.\n");