perf expr: Fix "has_event" function for metric style events

Events in metrics cannot use '/' as a separator, it would be
recognized as a divide, so they use '@'. The '@' is recognized in the
metricgroups code and changed to '/', do the same in the has_event
function so that the parsing is only tried without the @s.

Fixes: 4a4a9bf9075f ("perf expr: Add has_event function")
Signed-off-by: Ian Rogers <[e-mail]>
Reviewed-by: Kan Liang <[e-mail]>
Cc: K Prateek Nayak <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Kaige Ye <[e-mail]>
Cc: John Garry <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

tools/perf/util/expr.c

···
 	tmp = evlist__new();
 	if (!tmp)
 		return NAN;
-	ret = parse_event(tmp, id) ? 0 : 1;
+
+	if (strchr(id, '@')) {
+		char *tmp_id, *p;
+
+		tmp_id = strdup(id);
+		if (!tmp_id) {
+			ret = NAN;
+			goto out;
+		}
+		p = strchr(tmp_id, '@');
+		*p = '/';
+		p = strrchr(tmp_id, '@');
+		*p = '/';
+		ret = parse_event(tmp, tmp_id) ? 0 : 1;
+		free(tmp_id);
+	} else {
+		ret = parse_event(tmp, id) ? 0 : 1;
+	}
+out:
 	evlist__delete(tmp);
 	return ret;
 }