[tsan] Add support for GCD target queues

GCD (libdispatch) has a concept of “target queues”: Each queue has either an implicit or explicit target queue, where the task is handed over to when it’s time to execute it. For example, a concurrent queue can have a serial target queue (effectively making the first queue serial), or multiple queues can have the same serial target queue (which means tasks in all the queues are mutually excluded). Thus we need to acquire-release semantics on the full “chain” of target queues.

This patch changes the way we Acquire() and Release() when executing tasks in queues. Now we’ll walk the chain of target queues and synchronize on each queue that is serial (or when dealing with a barrier block). This should avoid false positives when using dispatch_set_target_queue().

Differential Revision: https://reviews.llvm.org/D25835



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@285613 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 41 insertions, 0 deletions

diff --git a/test/tsan/Darwin/gcd-target-queue-norace.mm b/test/tsan/Darwin/gcd-target-queue-norace.mm
new file mode 100644
index 000000000..36cb1b929
--- /dev/null
+++ b/test/tsan/Darwin/gcd-target-queue-norace.mm
@@ -0,0 +1,41 @@
+// 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 global;
+
+int main(int argc, const char *argv[]) {
+  dispatch_queue_t target_queue = dispatch_queue_create(NULL, DISPATCH_QUEUE_SERIAL);
+  dispatch_queue_t q1 = dispatch_queue_create(NULL, DISPATCH_QUEUE_CONCURRENT);
+  dispatch_queue_t q2 = dispatch_queue_create(NULL, DISPATCH_QUEUE_CONCURRENT);
+  dispatch_set_target_queue(q1, target_queue);
+  dispatch_set_target_queue(q2, target_queue);
+
+  for (int i = 0; i < 100000; i++) {
+    dispatch_async(q1, ^{
+      global++;
+
+      if (global == 200000) {
+        dispatch_sync(dispatch_get_main_queue(), ^{
+          CFRunLoopStop(CFRunLoopGetCurrent());
+        });
+      }
+    });
+    dispatch_async(q2, ^{
+      global++;
+
+      if (global == 200000) {
+        dispatch_sync(dispatch_get_main_queue(), ^{
+          CFRunLoopStop(CFRunLoopGetCurrent());
+        });
+      }
+    });
+  }
+
+  CFRunLoopRun();
+  NSLog(@"Done.");
+  return 0;
+}
+
+// CHECK-NOT: WARNING: ThreadSanitizer