perf metric: Collect referenced metrics in struct metric_expr

Add referenced metrics into struct metric_expr object, so they are
accessible when computing the metric.

Storing just name and expression itself, so the metric can be resolved
and computed.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200719181320.785305-10-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/metricgroup.c

@@ -83,6 +83,7 @@ static void metric_event_delete(struct rblist *rblist __maybe_unused,
 	struct metric_expr *expr, *tmp;
 
 	list_for_each_entry_safe(expr, tmp, &me->head, nd) {
+		free(expr->metric_refs);
 		free(expr);
 	}
 
@@ -248,6 +249,7 @@ static int metricgroup__setup_events(struct list_head *groups,
 
 	list_for_each_entry (eg, groups, nd) {
 		struct evsel **metric_events;
+		struct metric_ref *metric_refs = NULL;
 
 		metric_events = calloc(sizeof(void *),
 				hashmap__size(&eg->pctx.ids) + 1);
@@ -279,6 +281,36 @@ static int metricgroup__setup_events(struct list_head *groups,
 			free(metric_events);
 			break;
 		}
+
+		/*
+		 * Collect and store collected nested expressions
+		 * for metric processing.
+		 */
+		if (eg->metric_refs_cnt) {
+			struct metric_ref_node *ref;
+
+			metric_refs = zalloc(sizeof(struct metric_ref) * (eg->metric_refs_cnt + 1));
+			if (!metric_refs) {
+				ret = -ENOMEM;
+				free(metric_events);
+				break;
+			}
+
+			i = 0;
+			list_for_each_entry(ref, &eg->metric_refs, list) {
+				/*
+				 * Intentionally passing just const char pointers,
+				 * originally from 'struct pmu_event' object.
+				 * We don't need to change them, so there's no
+				 * need to create our own copy.
+				 */
+				metric_refs[i].metric_name = ref->metric_name;
+				metric_refs[i].metric_expr = ref->metric_expr;
+				i++;
+			}
+		};
+
+		expr->metric_refs = metric_refs;
 		expr->metric_expr = eg->metric_expr;
 		expr->metric_name = eg->metric_name;
 		expr->metric_unit = eg->metric_unit;

tools/perf/util/metricgroup.h

@@ -18,12 +18,18 @@ struct metric_event {
 	struct list_head head; /* list of metric_expr */
 };
 
+struct metric_ref {
+	const char *metric_name;
+	const char *metric_expr;
+};
+
 struct metric_expr {
 	struct list_head nd;
 	const char *metric_expr;
 	const char *metric_name;
 	const char *metric_unit;
 	struct evsel **metric_events;
+	struct metric_ref *metric_refs;
 	int runtime;
 };