perf jevents: Fix event code for events referencing std arch events

The event code for events referencing std arch events is incorrectly
evaluated in json_events().

The issue is that je.event is evaluated properly from try_fixup(), but
later NULLified from the real_event() call, as "event" may be NULL.

Fix by setting "event" same je.event in try_fixup().

Also remove support for overwriting event code for events using std arch
events, as it is not used.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-By: Kajol Jain<kjain@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/1602170368-11892-1-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/pmu-events/jevents.c

@@ -505,20 +505,15 @@ static char *real_event(const char *name, char *event)
 }
 
 static int
-try_fixup(const char *fn, char *arch_std, unsigned long long eventcode,
-	  struct json_event *je)
+try_fixup(const char *fn, char *arch_std, struct json_event *je, char **event)
 {
 	/* try to find matching event from arch standard values */
 	struct event_struct *es;
 
 	list_for_each_entry(es, &arch_std_events, list) {
 		if (!strcmp(arch_std, es->name)) {
-			if (!eventcode && es->event) {
-				/* allow EventCode to be overridden */
-				free(je->event);
-				je->event = NULL;
-			}
 			FOR_ALL_EVENT_STRUCT_FIELDS(TRY_FIXUP_FIELD);
+			*event = je->event;
 			return 0;
 		}
 	}
@@ -678,7 +673,7 @@ static int json_events(const char *fn,
 			 * An arch standard event is referenced, so try to
 			 * fixup any unassigned values.
 			 */
-			err = try_fixup(fn, arch_std, eventcode, &je);
+			err = try_fixup(fn, arch_std, &je, &event);
 			if (err)
 				goto free_strings;
 		}