1 files changed, 44 insertions, 0 deletions
diff --git a/test/tsan/Darwin/gcd-sync-race.mm b/test/tsan/Darwin/gcd-sync-race.mm
new file mode 100644
index 000000000000..62901d9b2612
--- /dev/null
+++ b/test/tsan/Darwin/gcd-sync-race.mm
@@ -0,0 +1,44 @@
+// RUN: %clang_tsan %s -o %t -framework Foundation
+// RUN: %deflake %run %t 2>&1
+
+#import <Foundation/Foundation.h>
+
+#import "../test.h"
+
+long global;
+
+int main() {
+  NSLog(@"Hello world.");
+  NSLog(@"addr=%p\n", &global);
+  barrier_init(&barrier, 2);
+
+  dispatch_queue_t q1 = dispatch_queue_create("my.queue1", DISPATCH_QUEUE_CONCURRENT);
+  dispatch_queue_t q2 = dispatch_queue_create("my.queue2", DISPATCH_QUEUE_CONCURRENT);
+
+  global = 42;
+  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+    dispatch_sync(q1, ^{
+      global = 43;
+      barrier_wait(&barrier);
+    });
+  });
+  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+    dispatch_sync(q2, ^{
+      barrier_wait(&barrier);
+      global = 44;
+
+      dispatch_sync(dispatch_get_main_queue(), ^{
+        CFRunLoopStop(CFRunLoopGetCurrent());
+      });
+    });
+  });
+
+  CFRunLoopRun();
+  NSLog(@"Done.");
+}
+
+// CHECK: Hello world.
+// CHECK: addr=[[ADDR:0x[0-9,a-f]+]]
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK: Location is global 'global' at [[ADDR]] (global_race.cc.exe+0x{{[0-9,a-f]+}})
+// CHECK: Done.