[test] Only update FLAG_local_heaps if disabled

Avoid data race by only setting FLAG_local_heaps to true if not
already enabled.

Bug: v8:10315
Change-Id: Ib562b6d525448f5c088da39bf60928debd97db43
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2426610
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70115}

test/cctest/heap/heap-utils.cc

@@ -246,6 +246,12 @@ bool InCorrectGeneration(HeapObject object) {
                                 : i::Heap::InYoungGeneration(object);
 }
 
+void EnsureFlagLocalHeapsEnabled() {
+  // Avoid data race in concurrent thread by only setting the flag to true if
+  // not already enabled.
+  if (!FLAG_local_heaps) FLAG_local_heaps = true;
+}
+
 }  // namespace heap
 }  // namespace internal
 }  // namespace v8

test/cctest/heap/heap-utils.h

@@ -70,6 +70,8 @@ void InvokeScavenge(Isolate* isolate = nullptr);
 
 void InvokeMarkSweep(Isolate* isolate = nullptr);
 
+void EnsureFlagLocalHeapsEnabled();
+
 template <typename GlobalOrPersistent>
 bool InYoungGeneration(v8::Isolate* isolate, const GlobalOrPersistent& global) {
   v8::HandleScope scope(isolate);

test/cctest/heap/test-heap.cc

@@ -7206,7 +7206,7 @@ TEST(Regress978156) {
 }
 
 TEST(GarbageCollectionWithLocalHeap) {
-  FLAG_local_heaps = true;
+  EnsureFlagLocalHeapsEnabled();
   ManualGCScope manual_gc_scope;
   CcTest::InitializeVM();
 

test/cctest/test-concurrent-descriptor-array.cc

@@ -70,7 +70,7 @@ class ConcurrentSearchThread final : public v8::base::Thread {
 
 // Uses linear search on a flat object, with up to 8 elements.
 TEST(LinearSearchFlatObject) {
-  FLAG_local_heaps = true;
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -122,8 +122,8 @@ TEST(LinearSearchFlatObject) {
 
 // Uses linear search on a flat object, which has more than 8 elements.
 TEST(LinearSearchFlatObject_ManyElements) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   std::unique_ptr<PersistentHandles> ph = isolate->NewPersistentHandles();

test/cctest/test-concurrent-prototype.cc

@@ -68,8 +68,8 @@ class ConcurrentSearchThread final : public v8::base::Thread {
 
 // Test to search on a background thread, while the main thread is idle.
 TEST(ProtoWalkBackground) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   std::unique_ptr<PersistentHandles> ph = isolate->NewPersistentHandles();
@@ -108,8 +108,8 @@ TEST(ProtoWalkBackground) {
 // Test to search on a background thread, while the main thread modifies the
 // descriptor array.
 TEST(ProtoWalkBackground_DescriptorArrayWrite) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   std::unique_ptr<PersistentHandles> ph = isolate->NewPersistentHandles();
@@ -155,8 +155,8 @@ TEST(ProtoWalkBackground_DescriptorArrayWrite) {
 }
 
 TEST(ProtoWalkBackground_PrototypeChainWrite) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   std::unique_ptr<PersistentHandles> ph = isolate->NewPersistentHandles();

test/cctest/test-local-handles.cc

@@ -69,8 +69,8 @@ class LocalHandlesThread final : public v8::base::Thread {
 };
 
 TEST(CreateLocalHandles) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   Address object = kNullAddress;
@@ -97,8 +97,8 @@ TEST(CreateLocalHandles) {
 }
 
 TEST(CreateLocalHandlesWithoutLocalHandleScope) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   {
@@ -108,8 +108,8 @@ TEST(CreateLocalHandlesWithoutLocalHandleScope) {
 }
 
 TEST(DereferenceLocalHandle) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   // Create a PersistentHandle to create the LocalHandle, and thus not have a

test/cctest/test-persistent-handles.cc

@@ -74,8 +74,8 @@ class PersistentHandlesThread final : public v8::base::Thread {
 };
 
 TEST(CreatePersistentHandles) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   std::unique_ptr<PersistentHandles> ph = isolate->NewPersistentHandles();
@@ -110,8 +110,8 @@ TEST(CreatePersistentHandles) {
 }
 
 TEST(DereferencePersistentHandle) {
+  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
-  FLAG_local_heaps = true;
   Isolate* isolate = CcTest::i_isolate();
 
   std::unique_ptr<PersistentHandles> phs = isolate->NewPersistentHandles();

test/unittests/heap/safepoint-unittest.cc

@@ -13,11 +13,17 @@
 namespace v8 {
 namespace internal {
 
+void EnsureFlagLocalHeapsEnabled() {
+  // Avoid data race in concurrent thread by only setting the flag to true if
+  // not already enabled.
+  if (!FLAG_local_heaps) FLAG_local_heaps = true;
+}
+
 using SafepointTest = TestWithIsolate;
 
 TEST_F(SafepointTest, ReachSafepointWithoutLocalHeaps) {
+  EnsureFlagLocalHeapsEnabled();
   Heap* heap = i_isolate()->heap();
-  FLAG_local_heaps = true;
   bool run = false;
   {
     SafepointScope scope(heap);
@@ -47,8 +53,8 @@ class ParkedThread final : public v8::base::Thread {
 };
 
 TEST_F(SafepointTest, StopParkedThreads) {
+  EnsureFlagLocalHeapsEnabled();
   Heap* heap = i_isolate()->heap();
-  FLAG_local_heaps = true;
 
   int safepoints = 0;
 
@@ -106,8 +112,8 @@ class RunningThread final : public v8::base::Thread {
 };
 
 TEST_F(SafepointTest, StopRunningThreads) {
+  EnsureFlagLocalHeapsEnabled();
   Heap* heap = i_isolate()->heap();
-  FLAG_local_heaps = true;
 
   const int kThreads = 10;
   const int kRuns = 5;
@@ -139,8 +145,8 @@ TEST_F(SafepointTest, StopRunningThreads) {
 }
 
 TEST_F(SafepointTest, SkipLocalHeapOfThisThread) {
+  EnsureFlagLocalHeapsEnabled();
   Heap* heap = i_isolate()->heap();
-  FLAG_local_heaps = true;
   LocalHeap local_heap(heap);
   {
     SafepointScope scope(heap);