[ASan] Fix GCD tests by spinning forever in the main thread.

Since the error is always reported by one of the GCD workers, this will help avoid premature program termination with exit code 0.

llvm-svn: 191294

compiler-rt/lib/asan/tests/asan_mac_test_helpers.mm

@@ -1,5 +1,6 @@
 // Mac OS X 10.6 or higher only.
 #include <dispatch/dispatch.h>
+#include <pthread.h>  // for pthread_yield_np()
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -11,26 +12,26 @@
 
 // This is a (void*)(void*) function so it can be passed to pthread_create.
 void *CFAllocatorDefaultDoubleFree(void *unused) {
-  void *mem =  CFAllocatorAllocate(kCFAllocatorDefault, 5, 0);
+  void *mem = CFAllocatorAllocate(kCFAllocatorDefault, 5, 0);
   CFAllocatorDeallocate(kCFAllocatorDefault, mem);
   CFAllocatorDeallocate(kCFAllocatorDefault, mem);
   return 0;
 }
 
 void CFAllocatorSystemDefaultDoubleFree() {
-  void *mem =  CFAllocatorAllocate(kCFAllocatorSystemDefault, 5, 0);
+  void *mem = CFAllocatorAllocate(kCFAllocatorSystemDefault, 5, 0);
   CFAllocatorDeallocate(kCFAllocatorSystemDefault, mem);
   CFAllocatorDeallocate(kCFAllocatorSystemDefault, mem);
 }
 
 void CFAllocatorMallocDoubleFree() {
-  void *mem =  CFAllocatorAllocate(kCFAllocatorMalloc, 5, 0);
+  void *mem = CFAllocatorAllocate(kCFAllocatorMalloc, 5, 0);
   CFAllocatorDeallocate(kCFAllocatorMalloc, mem);
   CFAllocatorDeallocate(kCFAllocatorMalloc, mem);
 }
 
 void CFAllocatorMallocZoneDoubleFree() {
-  void *mem =  CFAllocatorAllocate(kCFAllocatorMallocZone, 5, 0);
+  void *mem = CFAllocatorAllocate(kCFAllocatorMallocZone, 5, 0);
   CFAllocatorDeallocate(kCFAllocatorMallocZone, mem);
   CFAllocatorDeallocate(kCFAllocatorMallocZone, mem);
 }
@@ -77,10 +78,17 @@ void worker_do_crash(int size) {
   free(mem);
 }
 
+// Used by the GCD tests to avoid a race between the worker thread reporting a
+// memory error and the main thread which may exit with exit code 0 before
+// that.
+void wait_forever() {
+  volatile bool infinite = true;
+  while (infinite) pthread_yield_np();
+}
+
 // Tests for the Grand Central Dispatch. See
 // http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 // for the reference.
-
 void TestGCDDispatchAsync() {
   dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
   dispatch_block_t block = ^{ worker_do_crash(1024); };
@@ -88,8 +96,7 @@ void TestGCDDispatchAsync() {
   // pthread_create(). We need to verify that AddressSanitizer notices that the
   // thread has started.
   dispatch_async(queue, block);
-  // TODO(glider): this is hacky. Need to wait for the worker instead.
-  sleep(1);
+  wait_forever();
 }
 
 void TestGCDDispatchSync() {
@@ -99,8 +106,7 @@ void TestGCDDispatchSync() {
   // pthread_create(). We need to verify that AddressSanitizer notices that the
   // thread has started.
   dispatch_sync(queue, block);
-  // TODO(glider): this is hacky. Need to wait for the worker instead.
-  sleep(1);
+  wait_forever();
 }
 
 // libdispatch spawns a rather small number of threads and reuses them. We need
@@ -113,8 +119,7 @@ void TestGCDReuseWqthreadsAsync() {
     dispatch_async(queue, block_alloc);
   }
   dispatch_async(queue, block_crash);
-  // TODO(glider): this is hacky. Need to wait for the workers instead.
-  sleep(1);
+  wait_forever();
 }
 
 // Try to trigger abnormal behaviour of dispatch_sync() being unhandled by us.
@@ -130,8 +135,7 @@ void TestGCDReuseWqthreadsSync() {
     dispatch_sync(queue[i % 4], block_alloc);
   }
   dispatch_sync(queue[3], block_crash);
-  // TODO(glider): this is hacky. Need to wait for the workers instead.
-  sleep(1);
+  wait_forever();
 }
 
 void TestGCDDispatchAfter() {
@@ -141,9 +145,7 @@ void TestGCDDispatchAfter() {
   dispatch_time_t milestone =
       dispatch_time(DISPATCH_TIME_NOW, 1LL * NSEC_PER_SEC);
   dispatch_after(milestone, queue, block_crash);
-  // Let's wait for a bit longer now.
-  // TODO(glider): this is still hacky.
-  sleep(2);
+  wait_forever();
 }
 
 void worker_do_deallocate(void *ptr) {
@@ -172,7 +174,7 @@ void TestGCDSourceEvent() {
     access_memory(&mem[10]);
   });
   dispatch_resume(timer);
-  sleep(2);
+  wait_forever();
 }
 
 void TestGCDSourceCancel() {
@@ -196,7 +198,7 @@ void TestGCDSourceCancel() {
     access_memory(&mem[10]);
   });
   dispatch_resume(timer);
-  sleep(2);
+  wait_forever();
 }
 
 void TestGCDGroupAsync() {
@@ -207,6 +209,7 @@ void TestGCDGroupAsync() {
     access_memory(&mem[10]);
   });
   dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
+  wait_forever();
 }
 
 @interface FixedArray : NSObject {