Use local MicrotaskQueue in unittests

MicrotaskQueueTest uses Isolate's default_microtask_queue for testing,
however the instance is shared between test cases, and causes flaky
failure of MicrotaskQueueTest.BufferGrowth.

This CL adds a MicrotaskQueue instance for each test fixture, so that
each test cases use separate ones.

Also, this CL removes the DCHECK that denies non-default MicrotaskQueue
to run, which is unneeded after https://crrev.com/c/1369906.

Bug: v8:8124
Change-Id: I4ff236c327bf0be14f582b3ca8c802fd72661b42
Reviewed-on: https://chromium-review.googlesource.com/c/1417315Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58901}

src/execution.cc

@@ -258,13 +258,6 @@ V8_WARN_UNUSED_RESULT MaybeHandle<Object> Invoke(Isolate* isolate,
   Handle<Code> code =
       JSEntry(isolate, params.execution_target, params.is_construct);
   {
-    // Non-default MicrotaskQueue is currently unsupported.
-    // TODO(tzik): Remove this DCHECK once the entry function is ready to handle
-    // the microtask_queue parameter.
-    DCHECK_IMPLIES(
-        params.execution_target == Execution::Target::kRunMicrotasks,
-        params.microtask_queue == isolate->default_microtask_queue());
-
     // Save and restore context around invocation and block the
     // allocation of handles without explicit handle scopes.
     SaveContext save(isolate);

test/unittests/microtask-queue-unittest.cc

@@ -36,9 +36,27 @@ class MicrotaskQueueTest : public TestWithNativeContext {
     return factory()->NewCallbackTask(runner, data);
   }
 
+  void SetUp() override {
+    microtask_queue_ = MicrotaskQueue::New(isolate());
+    native_context()->set_microtask_queue(microtask_queue());
+  }
+
   void TearDown() override {
-    isolate()->default_microtask_queue()->RunMicrotasks(isolate());
+    if (microtask_queue()) {
+      microtask_queue()->RunMicrotasks(isolate());
+      context()->DetachGlobal();
+    }
+  }
+
+  MicrotaskQueue* microtask_queue() const { return microtask_queue_.get(); }
+
+  void ClearTestMicrotaskQueue() {
+    context()->DetachGlobal();
+    microtask_queue_ = nullptr;
   }
+
+ private:
+  std::unique_ptr<MicrotaskQueue> microtask_queue_;
 };
 
 class RecordingVisitor : public RootVisitor {
@@ -61,61 +79,57 @@ class RecordingVisitor : public RootVisitor {
 
 // Sanity check. Ensure a microtask is stored in a queue and run.
 TEST_F(MicrotaskQueueTest, EnqueueAndRun) {
-  MicrotaskQueue* microtask_queue = isolate()->default_microtask_queue();
-  ASSERT_TRUE(microtask_queue);
-
   bool ran = false;
-  EXPECT_EQ(0, microtask_queue->capacity());
-  EXPECT_EQ(0, microtask_queue->size());
-  microtask_queue->EnqueueMicrotask(*NewMicrotask([&ran] {
+  EXPECT_EQ(0, microtask_queue()->capacity());
+  EXPECT_EQ(0, microtask_queue()->size());
+  microtask_queue()->EnqueueMicrotask(*NewMicrotask([&ran] {
     EXPECT_FALSE(ran);
     ran = true;
   }));
-  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity, microtask_queue->capacity());
-  EXPECT_EQ(1, microtask_queue->size());
-  microtask_queue->RunMicrotasks(isolate());
+  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity, microtask_queue()->capacity());
+  EXPECT_EQ(1, microtask_queue()->size());
+  microtask_queue()->RunMicrotasks(isolate());
   EXPECT_TRUE(ran);
-  EXPECT_EQ(0, microtask_queue->size());
+  EXPECT_EQ(0, microtask_queue()->size());
 }
 
 // Check for a buffer growth.
 TEST_F(MicrotaskQueueTest, BufferGrowth) {
-  MicrotaskQueue* microtask_queue = isolate()->default_microtask_queue();
-  ASSERT_TRUE(microtask_queue);
-
   int count = 0;
 
   // Enqueue and flush the queue first to have non-zero |start_|.
-  microtask_queue->EnqueueMicrotask(
+  microtask_queue()->EnqueueMicrotask(
       *NewMicrotask([&count] { EXPECT_EQ(0, count++); }));
-  microtask_queue->RunMicrotasks(isolate());
+  microtask_queue()->RunMicrotasks(isolate());
 
-  EXPECT_LT(0, microtask_queue->capacity());
-  EXPECT_EQ(0, microtask_queue->size());
-  EXPECT_EQ(1, microtask_queue->start());
+  EXPECT_LT(0, microtask_queue()->capacity());
+  EXPECT_EQ(0, microtask_queue()->size());
+  EXPECT_EQ(1, microtask_queue()->start());
 
   // Fill the queue with Microtasks.
   for (int i = 1; i <= MicrotaskQueue::kMinimumCapacity; ++i) {
-    microtask_queue->EnqueueMicrotask(
+    microtask_queue()->EnqueueMicrotask(
         *NewMicrotask([&count, i] { EXPECT_EQ(i, count++); }));
   }
-  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity, microtask_queue->capacity());
-  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity, microtask_queue->size());
+  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity, microtask_queue()->capacity());
+  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity, microtask_queue()->size());
 
   // Add another to grow the ring buffer.
-  microtask_queue->EnqueueMicrotask(*NewMicrotask(
+  microtask_queue()->EnqueueMicrotask(*NewMicrotask(
       [&] { EXPECT_EQ(MicrotaskQueue::kMinimumCapacity + 1, count++); }));
 
-  EXPECT_LT(MicrotaskQueue::kMinimumCapacity, microtask_queue->capacity());
-  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity + 1, microtask_queue->size());
+  EXPECT_LT(MicrotaskQueue::kMinimumCapacity, microtask_queue()->capacity());
+  EXPECT_EQ(MicrotaskQueue::kMinimumCapacity + 1, microtask_queue()->size());
 
   // Run all pending Microtasks to ensure they run in the proper order.
-  microtask_queue->RunMicrotasks(isolate());
+  microtask_queue()->RunMicrotasks(isolate());
   EXPECT_EQ(MicrotaskQueue::kMinimumCapacity + 2, count);
 }
 
 // MicrotaskQueue instances form a doubly linked list.
 TEST_F(MicrotaskQueueTest, InstanceChain) {
+  ClearTestMicrotaskQueue();
+
   MicrotaskQueue* default_mtq = isolate()->default_microtask_queue();
   ASSERT_TRUE(default_mtq);
   EXPECT_EQ(default_mtq, default_mtq->next());
@@ -145,26 +159,23 @@ TEST_F(MicrotaskQueueTest, InstanceChain) {
 // Pending Microtasks in MicrotaskQueues are strong roots. Ensure they are
 // visited exactly once.
 TEST_F(MicrotaskQueueTest, VisitRoot) {
-  MicrotaskQueue* microtask_queue = isolate()->default_microtask_queue();
-  ASSERT_TRUE(microtask_queue);
-
   // Ensure that the ring buffer has separate in-use region.
   for (int i = 0; i < MicrotaskQueue::kMinimumCapacity / 2 + 1; ++i) {
-    microtask_queue->EnqueueMicrotask(*NewMicrotask([] {}));
+    microtask_queue()->EnqueueMicrotask(*NewMicrotask([] {}));
   }
-  microtask_queue->RunMicrotasks(isolate());
+  microtask_queue()->RunMicrotasks(isolate());
 
   std::vector<Object> expected;
   for (int i = 0; i < MicrotaskQueue::kMinimumCapacity / 2 + 1; ++i) {
     Handle<Microtask> microtask = NewMicrotask([] {});
     expected.push_back(*microtask);
-    microtask_queue->EnqueueMicrotask(*microtask);
+    microtask_queue()->EnqueueMicrotask(*microtask);
   }
-  EXPECT_GT(microtask_queue->start() + microtask_queue->size(),
-            microtask_queue->capacity());
+  EXPECT_GT(microtask_queue()->start() + microtask_queue()->size(),
+            microtask_queue()->capacity());
 
   RecordingVisitor visitor;
-  microtask_queue->IterateMicrotasks(&visitor);
+  microtask_queue()->IterateMicrotasks(&visitor);
 
   std::vector<Object> actual = visitor.visited();
   std::sort(expected.begin(), expected.end());

test/unittests/test-utils.h

@@ -222,7 +222,9 @@ class WithInternalIsolateMixin : public TMixin {
   Factory* factory() const { return isolate()->factory(); }
   Isolate* isolate() const { return TMixin::i_isolate(); }
 
-  Handle<Context> native_context() const { return isolate()->native_context(); }
+  Handle<NativeContext> native_context() const {
+    return isolate()->native_context();
+  }
 
   template <typename T = Object>
   Handle<T> RunJS(const char* source) {