[heap, infra] Remove --local-heaps and --concurrent-allocation flags

The flags are enabled by default and have stable coverage.
This also removes the corresponding bots.

Bug: v8:10315
Change-Id: Icce01383050dff758b6554db8e0c3589d6e5459c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2658324
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72457}

infra/testing/builders.pyl

@@ -294,7 +294,6 @@
       {'name': 'test262', 'shards': 7},
       {'name': 'v8testing', 'shards': 3},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 3},
-      {'name': 'v8testing', 'variant': 'no_local_heaps'},
       {'name': 'v8testing', 'variant': 'slow_path'},
     ],
   },
@@ -447,7 +446,6 @@
       {'name': 'test262', 'variant': 'default', 'shards': 3},
       {'name': 'v8testing', 'shards': 5},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 3},
-      {'name': 'v8testing', 'variant': 'no_local_heaps'},
       {'name': 'v8testing', 'variant': 'slow_path'},
       {'name': 'v8testing', 'variant': 'stress_concurrent_allocation'},
     ],
@@ -1201,7 +1199,6 @@
       {'name': 'test262', 'shards': 5},
       {'name': 'v8testing', 'shards': 2},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 2},
-      {'name': 'v8testing', 'variant': 'no_local_heaps', 'shards': 1},
       {'name': 'v8testing', 'variant': 'slow_path', 'shards': 1},
     ],
   },
@@ -1227,7 +1224,6 @@
       {'name': 'test262', 'variant': 'default', 'shards': 3},
       {'name': 'v8testing', 'shards': 5},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 3},
-      {'name': 'v8testing', 'variant': 'no_local_heaps', 'shards': 1},
       {'name': 'v8testing', 'variant': 'slow_path', 'shards': 1},
       {'name': 'v8testing', 'variant': 'stress_concurrent_allocation', 'shards': 1},
     ],

src/flags/flag-definitions.h

@@ -1036,19 +1036,8 @@ DEFINE_BOOL(concurrent_marking, V8_CONCURRENT_MARKING_BOOL,
             "use concurrent marking")
 DEFINE_BOOL(concurrent_array_buffer_sweeping, true,
             "concurrently sweep array buffers")
-DEFINE_BOOL(concurrent_allocation, true, "concurrently allocate in old space")
 DEFINE_BOOL(stress_concurrent_allocation, false,
             "start background threads that allocate memory")
-DEFINE_BOOL(local_heaps, true, "allow heap access from background tasks")
-// Since the local_heaps flag is enabled by default, we defined reverse
-// implications to simplify disabling the flag.
-DEFINE_NEG_NEG_IMPLICATION(local_heaps, turbo_direct_heap_access)
-DEFINE_NEG_NEG_IMPLICATION(local_heaps, stress_concurrent_inlining)
-DEFINE_NEG_NEG_IMPLICATION(local_heaps, concurrent_inlining)
-DEFINE_NEG_NEG_IMPLICATION(local_heaps, concurrent_allocation)
-DEFINE_NEG_NEG_IMPLICATION(concurrent_allocation,
-                           finalize_streaming_on_background)
-DEFINE_NEG_NEG_IMPLICATION(concurrent_allocation, stress_concurrent_allocation)
 DEFINE_BOOL(parallel_marking, V8_CONCURRENT_MARKING_BOOL,
             "use parallel marking in atomic pause")
 DEFINE_INT(ephemeron_fixpoint_iterations, 10,

src/handles/handles.cc

@@ -46,24 +46,22 @@ bool HandleBase::IsDereferenceAllowed() const {
   if (isolate->IsBuiltinsTableHandleLocation(location_)) return true;
   if (!AllowHandleDereference::IsAllowed()) return false;
 
-  if (FLAG_local_heaps) {
-    LocalHeap* local_heap = isolate->CurrentLocalHeap();
+  LocalHeap* local_heap = isolate->CurrentLocalHeap();
 
-    // Local heap can't access handles when parked
-    if (!local_heap->IsHandleDereferenceAllowed()) {
-      StdoutStream{} << "Cannot dereference handle owned by "
-                     << "non-running local heap\n";
-      return false;
-    }
+  // Local heap can't access handles when parked
+  if (!local_heap->IsHandleDereferenceAllowed()) {
+    StdoutStream{} << "Cannot dereference handle owned by "
+                   << "non-running local heap\n";
+    return false;
+  }
 
-    // We are pretty strict with handle dereferences on background threads: A
-    // background local heap is only allowed to dereference its own local or
-    // persistent handles.
-    if (!local_heap->is_main_thread()) {
-      // The current thread owns the handle and thus can dereference it.
-      return local_heap->ContainsPersistentHandle(location_) ||
-             local_heap->ContainsLocalHandle(location_);
-    }
+  // We are pretty strict with handle dereferences on background threads: A
+  // background local heap is only allowed to dereference its own local or
+  // persistent handles.
+  if (!local_heap->is_main_thread()) {
+    // The current thread owns the handle and thus can dereference it.
+    return local_heap->ContainsPersistentHandle(location_) ||
+           local_heap->ContainsLocalHandle(location_);
   }
   // If LocalHeap::Current() is null, we're on the main thread -- if we were to
   // check main thread HandleScopes here, we should additionally check the

src/handles/persistent-handles.cc

@@ -122,7 +122,7 @@ void PersistentHandlesList::Remove(PersistentHandles* persistent_handles) {
 }
 
 void PersistentHandlesList::Iterate(RootVisitor* visitor, Isolate* isolate) {
-  DCHECK_IMPLIES(FLAG_local_heaps, isolate->heap()->safepoint()->IsActive());
+  DCHECK(isolate->heap()->safepoint()->IsActive());
   base::MutexGuard guard(&persistent_handles_mutex_);
   for (PersistentHandles* current = persistent_handles_head_; current;
        current = current->next_) {

src/heap/concurrent-allocator-inl.h

@@ -21,8 +21,6 @@ AllocationResult ConcurrentAllocator::AllocateRaw(int object_size,
                                                   AllocationAlignment alignment,
                                                   AllocationOrigin origin) {
   // TODO(dinfuehr): Add support for allocation observers
-  CHECK(FLAG_concurrent_allocation);
-
 #ifdef DEBUG
   local_heap_->VerifyCurrent();
 #endif

src/heap/concurrent-allocator.cc

@@ -61,7 +61,6 @@ void StressConcurrentAllocatorTask::RunInternal() {
 
 // static
 void StressConcurrentAllocatorTask::Schedule(Isolate* isolate) {
-  CHECK(FLAG_local_heaps && FLAG_concurrent_allocation);
   auto task = std::make_unique<StressConcurrentAllocatorTask>(isolate);
   const double kDelayInSeconds = 0.1;
   V8::GetCurrentPlatform()->CallDelayedOnWorkerThread(std::move(task),

src/heap/heap.cc

@@ -1989,7 +1989,6 @@ GCTracer::Scope::ScopeId CollectorScopeId(GarbageCollector collector) {
 size_t Heap::PerformGarbageCollection(
     GarbageCollector collector, const v8::GCCallbackFlags gc_callback_flags) {
   DisallowJavascriptExecution no_js(isolate());
-  base::Optional<SafepointScope> optional_safepoint_scope;
 
   if (IsYoungGenerationCollector(collector)) {
     CompleteSweepingYoung(collector);
@@ -2008,9 +2007,7 @@ size_t Heap::PerformGarbageCollection(
 
   TRACE_GC_EPOCH(tracer(), CollectorScopeId(collector), ThreadKind::kMain);
 
-  if (FLAG_local_heaps) {
-    optional_safepoint_scope.emplace(this);
-  }
+  SafepointScope safepoint_scope(this);
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
@@ -3289,7 +3286,6 @@ void Heap::MakeHeapIterable() {
 }
 
 void Heap::MakeLocalHeapLabsIterable() {
-  if (!FLAG_local_heaps) return;
   safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
     local_heap->MakeLinearAllocationAreaIterable();
   });
@@ -4498,10 +4494,8 @@ void Heap::IterateRoots(RootVisitor* v, base::EnumSet<SkipRoot> options) {
     isolate_->handle_scope_implementer()->Iterate(v);
 #endif
 
-    if (FLAG_local_heaps) {
-      safepoint_->Iterate(&left_trim_visitor);
-      safepoint_->Iterate(v);
-    }
+    safepoint_->Iterate(&left_trim_visitor);
+    safepoint_->Iterate(v);
 
     isolate_->persistent_handles_list()->Iterate(&left_trim_visitor, isolate_);
     isolate_->persistent_handles_list()->Iterate(v, isolate_);

src/heap/incremental-marking.cc

@@ -261,11 +261,9 @@ void IncrementalMarking::StartBlackAllocation() {
   heap()->old_space()->MarkLinearAllocationAreaBlack();
   heap()->map_space()->MarkLinearAllocationAreaBlack();
   heap()->code_space()->MarkLinearAllocationAreaBlack();
-  if (FLAG_local_heaps) {
-    heap()->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
-      local_heap->MarkLinearAllocationAreaBlack();
-    });
-  }
+  heap()->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
+    local_heap->MarkLinearAllocationAreaBlack();
+  });
   if (FLAG_trace_incremental_marking) {
     heap()->isolate()->PrintWithTimestamp(
         "[IncrementalMarking] Black allocation started\n");
@@ -277,11 +275,8 @@ void IncrementalMarking::PauseBlackAllocation() {
   heap()->old_space()->UnmarkLinearAllocationArea();
   heap()->map_space()->UnmarkLinearAllocationArea();
   heap()->code_space()->UnmarkLinearAllocationArea();
-  if (FLAG_local_heaps) {
-    heap()->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
-      local_heap->UnmarkLinearAllocationArea();
-    });
-  }
+  heap()->safepoint()->IterateLocalHeaps(
+      [](LocalHeap* local_heap) { local_heap->UnmarkLinearAllocationArea(); });
   if (FLAG_trace_incremental_marking) {
     heap()->isolate()->PrintWithTimestamp(
         "[IncrementalMarking] Black allocation paused\n");
@@ -600,19 +595,17 @@ void IncrementalMarking::Stop() {
   is_compacting_ = false;
   FinishBlackAllocation();
 
-  if (FLAG_local_heaps) {
-    // Merge live bytes counters of background threads
-    for (auto pair : background_live_bytes_) {
-      MemoryChunk* memory_chunk = pair.first;
-      intptr_t live_bytes = pair.second;
+  // Merge live bytes counters of background threads
+  for (auto pair : background_live_bytes_) {
+    MemoryChunk* memory_chunk = pair.first;
+    intptr_t live_bytes = pair.second;
 
-      if (live_bytes) {
-        marking_state()->IncrementLiveBytes(memory_chunk, live_bytes);
-      }
+    if (live_bytes) {
+      marking_state()->IncrementLiveBytes(memory_chunk, live_bytes);
     }
-
-    background_live_bytes_.clear();
   }
+
+  background_live_bytes_.clear();
 }
 
 

src/heap/local-heap.cc

@@ -52,7 +52,7 @@ LocalHeap::LocalHeap(Heap* heap, ThreadKind kind,
       marking_barrier_(new MarkingBarrier(this)),
       old_space_allocator_(this, heap->old_space()) {
   heap_->safepoint()->AddLocalHeap(this, [this] {
-    if (FLAG_local_heaps && !is_main_thread()) {
+    if (!is_main_thread()) {
       WriteBarrier::SetForThread(marking_barrier_.get());
       if (heap_->incremental_marking()->IsMarking()) {
         marking_barrier_->Activate(
@@ -75,7 +75,7 @@ LocalHeap::~LocalHeap() {
   heap_->safepoint()->RemoveLocalHeap(this, [this] {
     old_space_allocator_.FreeLinearAllocationArea();
 
-    if (FLAG_local_heaps && !is_main_thread()) {
+    if (!is_main_thread()) {
       marking_barrier_->Publish();
       WriteBarrier::ClearForThread(marking_barrier_.get());
     }

src/heap/mark-compact.cc

@@ -858,11 +858,9 @@ void MarkCompactCollector::Prepare() {
     space->PrepareForMarkCompact();
   }
 
-  if (FLAG_local_heaps) {
-    // Fill and reset all background thread LABs
-    heap_->safepoint()->IterateLocalHeaps(
-        [](LocalHeap* local_heap) { local_heap->FreeLinearAllocationArea(); });
-  }
+  // Fill and reset all background thread LABs
+  heap_->safepoint()->IterateLocalHeaps(
+      [](LocalHeap* local_heap) { local_heap->FreeLinearAllocationArea(); });
 
   // All objects are guaranteed to be initialized in atomic pause
   heap()->new_lo_space()->ResetPendingObject();

src/heap/marking-barrier.cc

@@ -94,36 +94,27 @@ void MarkingBarrier::RecordRelocSlot(Code host, RelocInfo* rinfo,
 // static
 void MarkingBarrier::ActivateAll(Heap* heap, bool is_compacting) {
   heap->marking_barrier()->Activate(is_compacting);
-  if (FLAG_local_heaps) {
-    heap->safepoint()->IterateLocalHeaps(
-        [is_compacting](LocalHeap* local_heap) {
-          local_heap->marking_barrier()->Activate(is_compacting);
-        });
-  }
+  heap->safepoint()->IterateLocalHeaps([is_compacting](LocalHeap* local_heap) {
+    local_heap->marking_barrier()->Activate(is_compacting);
+  });
 }
 
 // static
 void MarkingBarrier::DeactivateAll(Heap* heap) {
   heap->marking_barrier()->Deactivate();
-  if (FLAG_local_heaps) {
-    heap->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
-      local_heap->marking_barrier()->Deactivate();
-    });
-  }
+  heap->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
+    local_heap->marking_barrier()->Deactivate();
+  });
 }
 
 // static
 void MarkingBarrier::PublishAll(Heap* heap) {
   heap->marking_barrier()->Publish();
-  if (FLAG_local_heaps) {
-    heap->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
-      local_heap->marking_barrier()->Publish();
-    });
-  }
+  heap->safepoint()->IterateLocalHeaps(
+      [](LocalHeap* local_heap) { local_heap->marking_barrier()->Publish(); });
 }
 
 void MarkingBarrier::Publish() {
-  DCHECK_IMPLIES(!is_main_thread_barrier_, FLAG_local_heaps);
   if (is_activated_) {
     worklist_.Publish();
     for (auto& it : typed_slots_map_) {
@@ -153,7 +144,6 @@ void MarkingBarrier::DeactivateSpace(NewSpace* space) {
 void MarkingBarrier::Deactivate() {
   is_activated_ = false;
   is_compacting_ = false;
-  DCHECK_IMPLIES(!is_main_thread_barrier_, FLAG_local_heaps);
   if (is_main_thread_barrier_) {
     DeactivateSpace(heap_->old_space());
     DeactivateSpace(heap_->map_space());
@@ -191,7 +181,6 @@ void MarkingBarrier::ActivateSpace(NewSpace* space) {
 void MarkingBarrier::Activate(bool is_compacting) {
   DCHECK(!is_activated_);
   DCHECK(worklist_.IsLocalEmpty());
-  DCHECK_IMPLIES(!is_main_thread_barrier_, FLAG_local_heaps);
   is_compacting_ = is_compacting;
   is_activated_ = true;
   if (is_main_thread_barrier_) {

src/heap/new-spaces.cc

@@ -429,7 +429,7 @@ void NewSpace::ResetParkedAllocationBuffers() {
 void NewSpace::Flip() { SemiSpace::Swap(&from_space_, &to_space_); }
 
 void NewSpace::Grow() {
-  DCHECK_IMPLIES(FLAG_local_heaps, heap()->safepoint()->IsActive());
+  DCHECK(heap()->safepoint()->IsActive());
   // Double the semispace size but only up to maximum capacity.
   DCHECK(TotalCapacity() < MaximumCapacity());
   size_t new_capacity = std::min(

src/heap/paged-spaces.h

@@ -326,9 +326,7 @@ class V8_EXPORT_PRIVATE PagedSpace
     base::Optional<base::MutexGuard> guard_;
   };
 
-  bool SupportsConcurrentAllocation() {
-    return FLAG_concurrent_allocation && !is_local_space();
-  }
+  bool SupportsConcurrentAllocation() { return !is_local_space(); }
 
   // Set space linear allocation area.
   void SetTopAndLimit(Address top, Address limit);

src/heap/safepoint.cc

@@ -18,8 +18,6 @@ GlobalSafepoint::GlobalSafepoint(Heap* heap)
     : heap_(heap), local_heaps_head_(nullptr), active_safepoint_scopes_(0) {}
 
 void GlobalSafepoint::EnterSafepointScope() {
-  if (!FLAG_local_heaps) return;
-
   if (++active_safepoint_scopes_ > 1) return;
 
   TimedHistogramScope timer(
@@ -54,8 +52,6 @@ void GlobalSafepoint::EnterSafepointScope() {
 }
 
 void GlobalSafepoint::LeaveSafepointScope() {
-  if (!FLAG_local_heaps) return;
-
   DCHECK_GT(active_safepoint_scopes_, 0);
   if (--active_safepoint_scopes_ > 0) return;
 

src/objects/string-table.cc

@@ -681,14 +681,14 @@ size_t StringTable::GetCurrentMemoryUsage() const {
 void StringTable::IterateElements(RootVisitor* visitor) {
   // This should only happen during garbage collection when background threads
   // are paused, so the load can be relaxed.
-  DCHECK_IMPLIES(FLAG_local_heaps, isolate_->heap()->safepoint()->IsActive());
+  DCHECK(isolate_->heap()->safepoint()->IsActive());
   data_.load(std::memory_order_relaxed)->IterateElements(visitor);
 }
 
 void StringTable::DropOldData() {
   // This should only happen during garbage collection when background threads
   // are paused, so the load can be relaxed.
-  DCHECK_IMPLIES(FLAG_local_heaps, isolate_->heap()->safepoint()->IsActive());
+  DCHECK(isolate_->heap()->safepoint()->IsActive());
   DCHECK_NE(isolate_->heap()->gc_state(), Heap::NOT_IN_GC);
   data_.load(std::memory_order_relaxed)->DropPreviousData();
 }
@@ -696,7 +696,7 @@ void StringTable::DropOldData() {
 void StringTable::NotifyElementsRemoved(int count) {
   // This should only happen during garbage collection when background threads
   // are paused, so the load can be relaxed.
-  DCHECK_IMPLIES(FLAG_local_heaps, isolate_->heap()->safepoint()->IsActive());
+  DCHECK(isolate_->heap()->safepoint()->IsActive());
   DCHECK_NE(isolate_->heap()->gc_state(), Heap::NOT_IN_GC);
   data_.load(std::memory_order_relaxed)->ElementsRemoved(count);
 }

test/cctest/compiler/serializer-tester.cc

@@ -22,10 +22,6 @@ SerializerTester::SerializerTester(const char* source)
     : canonical_(main_isolate()) {
   // The tests only make sense in the context of concurrent compilation.
   FLAG_concurrent_inlining = true;
-  // --local-heaps is enabled by default, but some bots disable it.
-  // Ensure that it is enabled here because we have reverse implication
-  // from --no-local-heaps to --no-concurrent-inlining.
-  if (!FLAG_local_heaps) FLAG_local_heaps = true;
   // The tests don't make sense when optimizations are turned off.
   FLAG_opt = true;
   // We need the IC to feed it to the serializer.

test/cctest/heap/heap-utils.cc

@@ -243,12 +243,6 @@ 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;
-}
-
 void GrowNewSpace(Heap* heap) {
   SafepointScope scope(heap);
   if (!heap->new_space()->IsAtMaximumCapacity()) {

test/cctest/heap/heap-utils.h

@@ -70,8 +70,6 @@ void InvokeScavenge(Isolate* isolate = nullptr);
 
 void InvokeMarkSweep(Isolate* isolate = nullptr);
 
-void EnsureFlagLocalHeapsEnabled();
-
 void GrowNewSpace(Heap* heap);
 
 void GrowNewSpaceToMaximumCapacity(Heap* heap);

test/cctest/heap/test-concurrent-allocation.cc

@@ -83,8 +83,6 @@ class ConcurrentAllocationThread final : public v8::base::Thread {
 
 UNINITIALIZED_TEST(ConcurrentAllocationInOldSpace) {
   FLAG_max_old_space_size = 32;
-  FLAG_concurrent_allocation = true;
-  FLAG_local_heaps = true;
   FLAG_stress_concurrent_allocation = false;
 
   v8::Isolate::CreateParams create_params;
@@ -118,8 +116,6 @@ UNINITIALIZED_TEST(ConcurrentAllocationInOldSpace) {
 
 UNINITIALIZED_TEST(ConcurrentAllocationInOldSpaceFromMainThread) {
   FLAG_max_old_space_size = 4;
-  FLAG_concurrent_allocation = true;
-  FLAG_local_heaps = true;
   FLAG_stress_concurrent_allocation = false;
 
   v8::Isolate::CreateParams create_params;
@@ -167,8 +163,6 @@ class LargeObjectConcurrentAllocationThread final : public v8::base::Thread {
 
 UNINITIALIZED_TEST(ConcurrentAllocationInLargeSpace) {
   FLAG_max_old_space_size = 32;
-  FLAG_concurrent_allocation = true;
-  FLAG_local_heaps = true;
   FLAG_stress_concurrent_allocation = false;
 
   v8::Isolate::CreateParams create_params;
@@ -243,9 +237,6 @@ class ConcurrentBlackAllocationThread final : public v8::base::Thread {
 };
 
 UNINITIALIZED_TEST(ConcurrentBlackAllocation) {
-  FLAG_concurrent_allocation = true;
-  FLAG_local_heaps = true;
-
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
   v8::Isolate* isolate = v8::Isolate::New(create_params);
@@ -310,8 +301,6 @@ UNINITIALIZED_TEST(ConcurrentWriteBarrier) {
     return;
   }
   ManualGCScope manual_gc_scope;
-  FLAG_concurrent_allocation = true;
-  FLAG_local_heaps = true;
 
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
@@ -377,8 +366,6 @@ UNINITIALIZED_TEST(ConcurrentRecordRelocSlot) {
   }
   FLAG_manual_evacuation_candidates_selection = true;
   ManualGCScope manual_gc_scope;
-  FLAG_concurrent_allocation = true;
-  FLAG_local_heaps = true;
 
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();

test/cctest/heap/test-heap.cc

@@ -7116,7 +7116,6 @@ TEST(Regress978156) {
 }
 
 TEST(GarbageCollectionWithLocalHeap) {
-  EnsureFlagLocalHeapsEnabled();
   ManualGCScope manual_gc_scope;
   CcTest::InitializeVM();
 

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

@@ -70,7 +70,6 @@ class ConcurrentSearchThread final : public v8::base::Thread {
 
 // Uses linear search on a flat object, with up to 8 elements.
 TEST(LinearSearchFlatObject) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -122,7 +121,6 @@ TEST(LinearSearchFlatObject) {
 
 // Uses linear search on a flat object, which has more than 8 elements.
 TEST(LinearSearchFlatObject_ManyElements) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 

test/cctest/test-concurrent-feedback-vector.cc

@@ -156,7 +156,6 @@ static void CheckedWait(base::Semaphore& semaphore) {
 // Verify that a LoadIC can be cycled through different states and safely
 // read on a background thread.
 TEST(CheckLoadICStates) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   FLAG_lazy_feedback_allocation = false;
   Isolate* isolate = CcTest::i_isolate();

test/cctest/test-concurrent-prototype.cc

@@ -68,7 +68,6 @@ 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();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -108,7 +107,6 @@ TEST(ProtoWalkBackground) {
 // Test to search on a background thread, while the main thread modifies the
 // descriptor array.
 TEST(ProtoWalkBackground_DescriptorArrayWrite) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -155,7 +153,6 @@ TEST(ProtoWalkBackground_DescriptorArrayWrite) {
 }
 
 TEST(ProtoWalkBackground_PrototypeChainWrite) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 

test/cctest/test-concurrent-string.cc

@@ -100,7 +100,6 @@ class ConcurrentStringThread final : public v8::base::Thread {
 
 // Inspect a one byte string, while the main thread externalizes it.
 TEST(InspectOneByteExternalizing) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -146,7 +145,6 @@ TEST(InspectOneByteExternalizing) {
 // Inspect a one byte string, while the main thread externalizes it into a two
 // bytes string.
 TEST(InspectOneIntoTwoByteExternalizing) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -189,7 +187,6 @@ TEST(InspectOneIntoTwoByteExternalizing) {
 
 // Inspect a two byte string, while the main thread externalizes it.
 TEST(InspectTwoByteExternalizing) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 

test/cctest/test-local-handles.cc

@@ -72,7 +72,6 @@ class LocalHandlesThread final : public v8::base::Thread {
 };
 
 TEST(CreateLocalHandles) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -100,7 +99,6 @@ TEST(CreateLocalHandles) {
 }
 
 TEST(CreateLocalHandlesWithoutLocalHandleScope) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
   HandleScope handle_scope(isolate);
@@ -109,7 +107,6 @@ TEST(CreateLocalHandlesWithoutLocalHandleScope) {
 }
 
 TEST(DereferenceLocalHandle) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -133,7 +130,6 @@ TEST(DereferenceLocalHandle) {
 }
 
 TEST(DereferenceLocalHandleFailsWhenDisallowed) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 

test/cctest/test-persistent-handles.cc

@@ -83,7 +83,6 @@ class PersistentHandlesThread final : public v8::base::Thread {
 };
 
 TEST(CreatePersistentHandles) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -119,7 +118,6 @@ TEST(CreatePersistentHandles) {
 }
 
 TEST(DereferencePersistentHandle) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 
@@ -139,7 +137,6 @@ TEST(DereferencePersistentHandle) {
 }
 
 TEST(DereferencePersistentHandleFailsWhenDisallowed) {
-  heap::EnsureFlagLocalHeapsEnabled();
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
 

test/unittests/heap/local-factory-unittest.cc

@@ -63,7 +63,6 @@ class LocalFactoryTest : public TestWithIsolateAndZone {
                 REPLMode::kNo),
             &state_),
         local_isolate_(isolate()->main_thread_local_isolate()) {
-    FLAG_concurrent_allocation = true;
   }
 
   FunctionLiteral* ParseProgram(const char* source) {

test/unittests/heap/safepoint-unittest.cc

@@ -15,16 +15,9 @@
 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();
   bool run = false;
   {
@@ -54,7 +47,6 @@ class ParkedThread final : public v8::base::Thread {
 };
 
 TEST_F(SafepointTest, StopParkedThreads) {
-  EnsureFlagLocalHeapsEnabled();
   Heap* heap = i_isolate()->heap();
 
   int safepoints = 0;
@@ -114,7 +106,6 @@ class RunningThread final : public v8::base::Thread {
 };
 
 TEST_F(SafepointTest, StopRunningThreads) {
-  EnsureFlagLocalHeapsEnabled();
   Heap* heap = i_isolate()->heap();
 
   const int kThreads = 10;

tools/testrunner/local/variants.py

@@ -16,10 +16,6 @@ ALL_VARIANT_FLAGS = {
   "jitless": [["--jitless"]],
   "minor_mc": [["--minor-mc"]],
   "no_lfa": [["--no-lazy-feedback-allocation"]],
-  "no_local_heaps": [[
-      "--no-local-heaps",
-      "--no-turbo-direct-heap-access",
-      "--no-finalize-streaming-on-background"]],
   # No optimization means disable all optimizations. OptimizeFunctionOnNextCall
   # would not force optimization too. It turns into a Nop. Please see
   # https://chromium-review.googlesource.com/c/452620/ for more discussion.