libperf: Adopt evlist__set_leader() from tools/perf as perf_evlist__set_leader()

Move the implementation of evlist__set_leader() to a new libperf
perf_evlist__set_leader() function with the same functionality make it a
libperf exported API.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Requested-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210706151704.73662-6-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/perf/evlist.c

@@ -642,3 +642,24 @@ perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
 
 	return overwrite ? evlist->mmap_ovw_first : evlist->mmap_first;
 }
+
+void __perf_evlist__set_leader(struct list_head *list)
+{
+	struct perf_evsel *evsel, *leader;
+
+	leader = list_entry(list->next, struct perf_evsel, node);
+	evsel = list_entry(list->prev, struct perf_evsel, node);
+
+	leader->nr_members = evsel->idx - leader->idx + 1;
+
+	__perf_evlist__for_each_entry(list, evsel)
+		evsel->leader = leader;
+}
+
+void perf_evlist__set_leader(struct perf_evlist *evlist)
+{
+	if (evlist->nr_entries) {
+		evlist->nr_groups = evlist->nr_entries > 1 ? 1 : 0;
+		__perf_evlist__set_leader(&evlist->entries);
+	}
+}

tools/lib/perf/include/internal/evlist.h

@@ -127,4 +127,5 @@ int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 
 void perf_evlist__reset_id_hash(struct perf_evlist *evlist);
 
+void __perf_evlist__set_leader(struct list_head *list);
 #endif /* __LIBPERF_INTERNAL_EVLIST_H */

tools/lib/perf/include/perf/evlist.h

@@ -46,4 +46,5 @@ LIBPERF_API struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
 	     (pos) != NULL;						\
 	     (pos) = perf_evlist__next_mmap((evlist), (pos), overwrite))
 
+LIBPERF_API void perf_evlist__set_leader(struct perf_evlist *evlist);
 #endif /* __LIBPERF_EVLIST_H */

tools/lib/perf/libperf.map

@@ -45,6 +45,7 @@ LIBPERF_0.0.1 {
 		perf_evlist__munmap;
 		perf_evlist__filter_pollfd;
 		perf_evlist__next_mmap;
+		perf_evlist__set_leader;
 		perf_mmap__consume;
 		perf_mmap__read_init;
 		perf_mmap__read_done;

tools/perf/util/evlist.c

@@ -223,26 +223,9 @@ out:
 	return err;
 }
 
-void __evlist__set_leader(struct list_head *list)
-{
-	struct evsel *evsel, *leader;
-
-	leader = list_entry(list->next, struct evsel, core.node);
-	evsel = list_entry(list->prev, struct evsel, core.node);
-
-	leader->core.nr_members = evsel->core.idx - leader->core.idx + 1;
-
-	__evlist__for_each_entry(list, evsel) {
-		evsel->core.leader = &leader->core;
-	}
-}
-
 void evlist__set_leader(struct evlist *evlist)
 {
-	if (evlist->core.nr_entries) {
-		evlist->core.nr_groups = evlist->core.nr_entries > 1 ? 1 : 0;
-		__evlist__set_leader(&evlist->core.entries);
-	}
+	perf_evlist__set_leader(&evlist->core);
 }
 
 int __evlist__add_default(struct evlist *evlist, bool precise)

tools/perf/util/evlist.h

@@ -201,7 +201,6 @@ void evlist__set_selected(struct evlist *evlist, struct evsel *evsel);
 int evlist__create_maps(struct evlist *evlist, struct target *target);
 int evlist__apply_filters(struct evlist *evlist, struct evsel **err_evsel);
 
-void __evlist__set_leader(struct list_head *list);
 void evlist__set_leader(struct evlist *evlist);
 
 u64 __evlist__combined_sample_type(struct evlist *evlist);

tools/perf/util/parse-events.c

@@ -1833,7 +1833,7 @@ void parse_events__set_leader(char *name, struct list_head *list,
 	if (parse_events__set_leader_for_uncore_aliase(name, list, parse_state))
 		return;
 
-	__evlist__set_leader(list);
+	__perf_evlist__set_leader(list);
 	leader = list_entry(list->next, struct evsel, core.node);
 	leader->group_name = name ? strdup(name) : NULL;
 }