[PATCH v4 1/3] perf evlist: Create new function perf_evlist__force_leader

[Jin Yao <yao.jin@linux.intel.com>]

For non-explicit group, perf report supports a option '--group'
which can enable group output. We also need to support perf annotate
with the same '--group'.

Create a new function perf_evlist__force_leader which contains
common code to force setting the group leader.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
 tools/perf/util/evlist.c | 15 +++++++++++++++
 tools/perf/util/evlist.h |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index a59281d..e7a4b31 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1795,3 +1795,18 @@ bool perf_evlist__exclude_kernel(struct perf_evlist *evlist)
 
 	return true;
 }
+
+/*
+ * Events in data file are not collect in groups, but we still want
+ * the group display. Set the artificial group and set the leader's
+ * forced_leader flag to notify the display code.
+ */
+void perf_evlist__force_leader(struct perf_evlist *evlist)
+{
+	if (!evlist->nr_groups) {
+		struct perf_evsel *leader = perf_evlist__first(evlist);
+
+		perf_evlist__set_leader(evlist);
+		leader->forced_leader = true;
+	}
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 6c41b2f..dc66436 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -309,4 +309,7 @@ struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
 					    union perf_event *event);
 
 bool perf_evlist__exclude_kernel(struct perf_evlist *evlist);
+
+void perf_evlist__force_leader(struct perf_evlist *evlist);
+
 #endif /* __PERF_EVLIST_H */
-- 
2.7.4