1 files changed, 54 insertions, 0 deletions
diff --git a/test/tsan/libdispatch/once.c b/test/tsan/libdispatch/once.c
new file mode 100644
index 000000000..d473b3426
--- /dev/null
+++ b/test/tsan/libdispatch/once.c
@@ -0,0 +1,54 @@
+// RUN: %clang_tsan %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer'
+
+#include <dispatch/dispatch.h>
+
+#include "../test.h"
+
+static const long kNumThreads = 4;
+
+long global;
+long global2;
+
+static dispatch_once_t once_token;
+static dispatch_once_t once_token2;
+
+void f(void *a) {
+  global2 = 42;
+  usleep(100000);
+}
+
+void *Thread(void *a) {
+  barrier_wait(&barrier);
+
+  dispatch_once(&once_token, ^{
+    global = 42;
+    usleep(100000);
+  });
+  long x = global;
+
+  dispatch_once_f(&once_token2, NULL, f);
+  long x2 = global2;
+
+  fprintf(stderr, "global = %ld\n", x);
+  fprintf(stderr, "global2 = %ld\n", x2);
+  return 0;
+}
+
+int main() {
+  fprintf(stderr, "Hello world.\n");
+  barrier_init(&barrier, kNumThreads);
+
+  pthread_t t[kNumThreads];
+  for (int i = 0; i < kNumThreads; i++) {
+    pthread_create(&t[i], 0, Thread, 0);
+  }
+  for (int i = 0; i < kNumThreads; i++) {
+    pthread_join(t[i], 0);
+  }
+
+  fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello world.
+// CHECK: Done.