perf sched: Avoid union type punning undefined behavior

A union is used to set the priv value in thread (a void*) to a boolean
value through type punning. Undefined behavior sanitizer fails on this.

Signed-off-by: Ian Rogers <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-sched.c

···
 	return 0;
 }
 
-union map_priv {
-	void	*ptr;
-	bool	 color;
-};
-
 static bool thread__has_color(struct thread *thread)
 {
-	union map_priv priv = {
-		.ptr = thread__priv(thread),
-	};
-
-	return priv.color;
+	return thread__priv(thread) != NULL;
 }
 
 static struct thread*
 map__findnew_thread(struct perf_sched *sched, struct machine *machine, pid_t pid, pid_t tid)
 {
 	struct thread *thread = machine__findnew_thread(machine, pid, tid);
-	union map_priv priv = {
-		.color = false,
-	};
+	bool color = false;
 
 	if (!sched->map.color_pids || !thread || thread__priv(thread))
 		return thread;
 
 	if (thread_map__has(sched->map.color_pids, tid))
-		priv.color = true;
+		color = true;
 
-	thread__set_priv(thread, priv.ptr);
+	thread__set_priv(thread, color ? ((void*)1) : NULL);
 	return thread;
 }