[tsan] Replace pthread semaphore in signal_cond.cc with barrier_wait

Pthread semaphores are not available on OS X. Let's replace sem_wait/sem_post with barrier_wait, which makes the test pass on OS X. I know that sem_wait/sem_post is intercepted by TSan, whereas barrier_wait is TSan-invisible, but the purpose of the test is not affected by this.

Also, let's properly initialize the mutex and cond variables.

Differential Revision: http://reviews.llvm.org/D14924

llvm-svn: 253980

compiler-rt/test/tsan/signal_cond.cc

@@ -11,12 +11,11 @@
 int g_thread_run = 1;
 pthread_mutex_t mutex;
 pthread_cond_t cond;
-sem_t sem;
 
 void sig_handler(int sig) {
   (void)sig;
   write(1, "SIGNAL\n", sizeof("SIGNAL\n") - 1);
-  sem_post(&sem);
+  barrier_wait(&barrier);
 }
 
 void* my_thread(void* arg) {
@@ -28,16 +27,19 @@ void* my_thread(void* arg) {
 }
 
 int main() {
-  sem_init(&sem, 0, 0);
+  barrier_init(&barrier, 2);
+
+  pthread_mutex_init(&mutex, 0);
+  pthread_cond_init(&cond, 0);
+
   signal(SIGUSR1, &sig_handler);
   pthread_t thr;
   pthread_create(&thr, 0, &my_thread, 0);
   // wait for thread to get inside pthread_cond_wait
   // (can't use barrier_wait for that)
   sleep(1);
   pthread_kill(thr, SIGUSR1);
-  while (sem_wait(&sem) == -1 && errno == EINTR) {
-  }
+  barrier_wait(&barrier);
   pthread_mutex_lock(&mutex);
   g_thread_run = 0;
   pthread_cond_signal(&cond);