[tsan] Add support for GCD dispatch_suspend and dispatch_resume
GCD queues can be suspended and resumed with dispatch_suspend and dispatch_resume. We need to add synchronization between the call to dispatch_resume and any subsequent executions of blocks in the queue that was resumed. We already have an Acquire(q) before the block executes, so this patch just adds the Release(q) in an interceptor of dispatch_resume.
Differential Revision: https://reviews.llvm.org/D27112
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@287902 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/tsan/rtl/tsan_libdispatch_mac.cc b/lib/tsan/rtl/tsan_libdispatch_mac.cc
index 2bd8161..d8c689e 100644
--- a/lib/tsan/rtl/tsan_libdispatch_mac.cc
+++ b/lib/tsan/rtl/tsan_libdispatch_mac.cc
@@ -706,6 +706,15 @@
return REAL(dispatch_io_close)(channel, flags);
}
+// Resuming a suspended queue needs to synchronize with all subsequent
+// executions of blocks in that queue.
+TSAN_INTERCEPTOR(void, dispatch_resume, dispatch_object_t o) {
+ SCOPED_TSAN_INTERCEPTOR(dispatch_resume, o);
+ Release(thr, pc, (uptr)o); // Synchronizes with the Acquire() on serial_sync
+ // in dispatch_sync_pre_execute
+ return REAL(dispatch_resume)(o);
+}
+
} // namespace __tsan
#endif // SANITIZER_MAC
diff --git a/test/tsan/Darwin/gcd-suspend.mm b/test/tsan/Darwin/gcd-suspend.mm
new file mode 100644
index 0000000..3e8818a
--- /dev/null
+++ b/test/tsan/Darwin/gcd-suspend.mm
@@ -0,0 +1,45 @@
+// RUN: %clang_tsan %s -o %t -framework Foundation
+// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+
+#import <Foundation/Foundation.h>
+
+long my_global = 0;
+
+int main(int argc, const char *argv[]) {
+ fprintf(stderr, "Hello world.\n");
+
+ dispatch_queue_t q1 = dispatch_queue_create("queue1", NULL);
+ dispatch_queue_t q2 = dispatch_queue_create("queue2", NULL);
+ dispatch_group_t g = dispatch_group_create();
+
+ dispatch_sync(q1, ^{
+ dispatch_suspend(q1);
+ dispatch_async(q2, ^{
+ my_global++;
+ dispatch_resume(q1);
+ });
+ });
+
+ dispatch_sync(q1, ^{
+ my_global++;
+ });
+
+ dispatch_sync(q1, ^{
+ dispatch_suspend(q1);
+ dispatch_group_enter(g);
+ dispatch_async(q1,^{ my_global++; });
+ dispatch_async(q1,^{ my_global++; });
+ dispatch_async(q1,^{ my_global++; dispatch_group_leave(g); });
+ my_global++;
+ dispatch_resume(q1);
+ });
+
+ dispatch_group_wait(g, DISPATCH_TIME_FOREVER);
+
+ fprintf(stderr, "Done.\n");
+ return 0;
+}
+
+// CHECK: Hello world.
+// CHECK-NOT: WARNING: ThreadSanitizer
+// CHECK: Done.
