perf tools: Add reference counting for thread_map object

Adding reference counting for thread_map object, so it could be easily
shared among other objects.

Using thread_map__put instead thread_map__delete and making
thread_map__delete static.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1435012588-9007-5-git-send-email-jolsa@kernel.org
[ Adjustments to move it ahead of the "comm" patches ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/thread_map.h

@@ -3,12 +3,14 @@
 
 #include <sys/types.h>
 #include <stdio.h>
+#include <linux/atomic.h>
 
 struct thread_map_data {
 	pid_t    pid;
 };
 
 struct thread_map {
+	atomic_t refcnt;
 	int nr;
 	struct thread_map_data map[];
 };
@@ -19,11 +21,12 @@ struct thread_map *thread_map__new_by_tid(pid_t tid);
 struct thread_map *thread_map__new_by_uid(uid_t uid);
 struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid);
 
+struct thread_map *thread_map__get(struct thread_map *map);
+void thread_map__put(struct thread_map *map);
+
 struct thread_map *thread_map__new_str(const char *pid,
 		const char *tid, uid_t uid);
 
-void thread_map__delete(struct thread_map *threads);
-
 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp);
 
 static inline int thread_map__nr(struct thread_map *threads)