1 files changed, 41 insertions, 336 deletions

diff --git a/deps/v8/src/execution/isolate.cc b/deps/v8/src/execution/isolate.cc
index 3ba39562b1..2b6bb76d8a 100644
--- a/deps/v8/src/execution/isolate.cc
+++ b/deps/v8/src/execution/isolate.cc
@@ -15,7 +15,6 @@
 #include "src/api/api-inl.h"
 #include "src/ast/ast-value-factory.h"
 #include "src/ast/scopes.h"
-#include "src/base/adapters.h"
 #include "src/base/hashmap.h"
 #include "src/base/platform/platform.h"
 #include "src/base/sys-info.h"
@@ -36,6 +35,7 @@
 #include "src/execution/isolate-inl.h"
 #include "src/execution/messages.h"
 #include "src/execution/microtask-queue.h"
+#include "src/execution/protectors-inl.h"
 #include "src/execution/runtime-profiler.h"
 #include "src/execution/simulator.h"
 #include "src/execution/v8threads.h"
@@ -51,6 +51,7 @@
 #include "src/logging/counters.h"
 #include "src/logging/log.h"
 #include "src/numbers/hash-seed-inl.h"
+#include "src/objects/backing-store.h"
 #include "src/objects/elements.h"
 #include "src/objects/frame-array-inl.h"
 #include "src/objects/hash-table-inl.h"
@@ -320,7 +321,9 @@ Isolate::FindOrAllocatePerThreadDataForThisThread() {
     base::MutexGuard lock_guard(&thread_data_table_mutex_);
     per_thread = thread_data_table_.Lookup(thread_id);
     if (per_thread == nullptr) {
-      base::OS::AdjustSchedulingParams();
+      if (FLAG_adjust_os_scheduling_parameters) {
+        base::OS::AdjustSchedulingParams();
+      }
       per_thread = new PerIsolateThreadData(this, thread_id);
       thread_data_table_.Insert(per_thread);
     }
@@ -1091,12 +1094,14 @@ Handle<Object> CaptureStackTrace(Isolate* isolate, Handle<Object> caller,
           } else {
             Handle<JSAsyncGeneratorObject> async_generator_object =
                 Handle<JSAsyncGeneratorObject>::cast(generator_object);
-            Handle<AsyncGeneratorRequest> async_generator_request(
-                AsyncGeneratorRequest::cast(async_generator_object->queue()),
-                isolate);
-            Handle<JSPromise> promise(
-                JSPromise::cast(async_generator_request->promise()), isolate);
-            CaptureAsyncStackTrace(isolate, promise, &builder);
+            Handle<Object> queue(async_generator_object->queue(), isolate);
+            if (!queue->IsUndefined(isolate)) {
+              Handle<AsyncGeneratorRequest> async_generator_request =
+                  Handle<AsyncGeneratorRequest>::cast(queue);
+              Handle<JSPromise> promise(
+                  JSPromise::cast(async_generator_request->promise()), isolate);
+              CaptureAsyncStackTrace(isolate, promise, &builder);
+            }
           }
         }
       } else {
@@ -1701,22 +1706,20 @@ Object Isolate::UnwindAndFindHandler() {
         // currently being executed.
         wasm::WasmCodeRefScope code_ref_scope;
         WasmCompiledFrame* wasm_frame = static_cast<WasmCompiledFrame*>(frame);
-        int stack_slots = 0;  // Will contain stack slot count of frame.
-        int offset = wasm_frame->LookupExceptionHandlerInTable(&stack_slots);
+        wasm::WasmCode* wasm_code =
+            wasm_engine()->code_manager()->LookupCode(frame->pc());
+        int offset = wasm_frame->LookupExceptionHandlerInTable();
         if (offset < 0) break;
         // Compute the stack pointer from the frame pointer. This ensures that
         // argument slots on the stack are dropped as returning would.
         Address return_sp = frame->fp() +
                             StandardFrameConstants::kFixedFrameSizeAboveFp -
-                            stack_slots * kSystemPointerSize;
+                            wasm_code->stack_slots() * kSystemPointerSize;
 
         // This is going to be handled by Wasm, so we need to set the TLS flag
         // again. It was cleared above assuming the frame would be unwound.
         trap_handler::SetThreadInWasm();
 
-        // Gather information from the frame.
-        wasm::WasmCode* wasm_code =
-            wasm_engine()->code_manager()->LookupCode(frame->pc());
         return FoundHandler(Context(), wasm_code->instruction_start(), offset,
                             wasm_code->constant_pool(), return_sp, frame->fp());
       }
@@ -1735,18 +1738,14 @@ Object Isolate::UnwindAndFindHandler() {
         // For optimized frames we perform a lookup in the handler table.
         if (!catchable_by_js) break;
         OptimizedFrame* js_frame = static_cast<OptimizedFrame*>(frame);
-        int stack_slots = 0;  // Will contain stack slot count of frame.
-        int offset =
-            js_frame->LookupExceptionHandlerInTable(&stack_slots, nullptr);
+        Code code = frame->LookupCode();
+        int offset = js_frame->LookupExceptionHandlerInTable(nullptr, nullptr);
         if (offset < 0) break;
         // Compute the stack pointer from the frame pointer. This ensures
         // that argument slots on the stack are dropped as returning would.
         Address return_sp = frame->fp() +
                             StandardFrameConstants::kFixedFrameSizeAboveFp -
-                            stack_slots * kSystemPointerSize;
-
-        // Gather information from the frame.
-        Code code = frame->LookupCode();
+                            code.stack_slots() * kSystemPointerSize;
 
         // TODO(bmeurer): Turbofanned BUILTIN frames appear as OPTIMIZED,
         // but do not have a code kind of OPTIMIZED_FUNCTION.
@@ -1767,31 +1766,24 @@ Object Isolate::UnwindAndFindHandler() {
         // Some stubs are able to handle exceptions.
         if (!catchable_by_js) break;
         StubFrame* stub_frame = static_cast<StubFrame*>(frame);
+#ifdef DEBUG
         wasm::WasmCodeRefScope code_ref_scope;
-        wasm::WasmCode* wasm_code =
-            wasm_engine()->code_manager()->LookupCode(frame->pc());
-        if (wasm_code != nullptr) {
-          // It is safe to skip Wasm runtime stubs as none of them contain local
-          // exception handlers.
-          CHECK_EQ(wasm::WasmCode::kRuntimeStub, wasm_code->kind());
-          CHECK_EQ(0, wasm_code->handler_table_size());
-          break;
-        }
+        DCHECK_NULL(wasm_engine()->code_manager()->LookupCode(frame->pc()));
+#endif  // DEBUG
         Code code = stub_frame->LookupCode();
         if (!code.IsCode() || code.kind() != Code::BUILTIN ||
             !code.has_handler_table() || !code.is_turbofanned()) {
           break;
         }
 
-        int stack_slots = 0;  // Will contain stack slot count of frame.
-        int offset = stub_frame->LookupExceptionHandlerInTable(&stack_slots);
+        int offset = stub_frame->LookupExceptionHandlerInTable();
         if (offset < 0) break;
 
         // Compute the stack pointer from the frame pointer. This ensures
         // that argument slots on the stack are dropped as returning would.
         Address return_sp = frame->fp() +
                             StandardFrameConstants::kFixedFrameSizeAboveFp -
-                            stack_slots * kSystemPointerSize;
+                            code.stack_slots() * kSystemPointerSize;
 
         return FoundHandler(Context(), code.InstructionStart(), offset,
                             code.constant_pool(), return_sp, frame->fp());
@@ -2063,7 +2055,7 @@ void Isolate::PrintCurrentStackTrace(FILE* out) {
   for (int i = 0; i < frames->length(); ++i) {
     Handle<StackTraceFrame> frame(StackTraceFrame::cast(frames->get(i)), this);
 
-    SerializeStackTraceFrame(this, frame, builder);
+    SerializeStackTraceFrame(this, frame, &builder);
   }
 
   Handle<String> stack_trace = builder.Finish().ToHandleChecked();
@@ -2821,7 +2813,7 @@ Isolate* Isolate::New(IsolateAllocationMode mode) {
   // IsolateAllocator allocates the memory for the Isolate object according to
   // the given allocation mode.
   std::unique_ptr<IsolateAllocator> isolate_allocator =
-      base::make_unique<IsolateAllocator>(mode);
+      std::make_unique<IsolateAllocator>(mode);
   // Construct Isolate object in the allocated memory.
   void* isolate_ptr = isolate_allocator->isolate_memory();
   Isolate* isolate = new (isolate_ptr) Isolate(std::move(isolate_allocator));
@@ -2986,7 +2978,7 @@ void Isolate::Deinit() {
     optimizing_compile_dispatcher_ = nullptr;
   }
 
-  wasm_engine()->memory_tracker()->DeleteSharedMemoryObjectsOnIsolate(this);
+  BackingStore::RemoveSharedWasmMemoryObjects(this);
 
   heap_.mark_compact_collector()->EnsureSweepingCompleted();
   heap_.memory_allocator()->unmapper()->EnsureUnmappingCompleted();
@@ -3805,308 +3797,12 @@ bool Isolate::IsInAnyContext(Object object, uint32_t index) {
   return false;
 }
 
-bool Isolate::IsNoElementsProtectorIntact(Context context) {
-  PropertyCell no_elements_cell = heap()->no_elements_protector();
-  bool cell_reports_intact =
-      no_elements_cell.value().IsSmi() &&
-      Smi::ToInt(no_elements_cell.value()) == kProtectorValid;
-
-#ifdef DEBUG
-  Context native_context = context.native_context();
-
-  Map root_array_map =
-      native_context.GetInitialJSArrayMap(GetInitialFastElementsKind());
-  JSObject initial_array_proto = JSObject::cast(
-      native_context.get(Context::INITIAL_ARRAY_PROTOTYPE_INDEX));
-  JSObject initial_object_proto = JSObject::cast(
-      native_context.get(Context::INITIAL_OBJECT_PROTOTYPE_INDEX));
-  JSObject initial_string_proto = JSObject::cast(
-      native_context.get(Context::INITIAL_STRING_PROTOTYPE_INDEX));
-
-  if (root_array_map.is_null() || initial_array_proto == initial_object_proto) {
-    // We are in the bootstrapping process, and the entire check sequence
-    // shouldn't be performed.
-    return cell_reports_intact;
-  }
-
-  // Check that the array prototype hasn't been altered WRT empty elements.
-  if (root_array_map.prototype() != initial_array_proto) {
-    DCHECK_EQ(false, cell_reports_intact);
-    return cell_reports_intact;
-  }
-
-  FixedArrayBase elements = initial_array_proto.elements();
-  ReadOnlyRoots roots(heap());
-  if (elements != roots.empty_fixed_array() &&
-      elements != roots.empty_slow_element_dictionary()) {
-    DCHECK_EQ(false, cell_reports_intact);
-    return cell_reports_intact;
-  }
-
-  // Check that the Object.prototype hasn't been altered WRT empty elements.
-  elements = initial_object_proto.elements();
-  if (elements != roots.empty_fixed_array() &&
-      elements != roots.empty_slow_element_dictionary()) {
-    DCHECK_EQ(false, cell_reports_intact);
-    return cell_reports_intact;
-  }
-
-  // Check that the Array.prototype has the Object.prototype as its
-  // [[Prototype]] and that the Object.prototype has a null [[Prototype]].
-  PrototypeIterator iter(this, initial_array_proto);
-  if (iter.IsAtEnd() || iter.GetCurrent() != initial_object_proto) {
-    DCHECK_EQ(false, cell_reports_intact);
-    DCHECK(!has_pending_exception());
-    return cell_reports_intact;
-  }
-  iter.Advance();
-  if (!iter.IsAtEnd()) {
-    DCHECK_EQ(false, cell_reports_intact);
-    DCHECK(!has_pending_exception());
-    return cell_reports_intact;
-  }
-  DCHECK(!has_pending_exception());
-
-  // Check that the String.prototype hasn't been altered WRT empty elements.
-  elements = initial_string_proto.elements();
-  if (elements != roots.empty_fixed_array() &&
-      elements != roots.empty_slow_element_dictionary()) {
-    DCHECK_EQ(false, cell_reports_intact);
-    return cell_reports_intact;
-  }
-
-  // Check that the String.prototype has the Object.prototype
-  // as its [[Prototype]] still.
-  if (initial_string_proto.map().prototype() != initial_object_proto) {
-    DCHECK_EQ(false, cell_reports_intact);
-    return cell_reports_intact;
-  }
-#endif
-
-  return cell_reports_intact;
-}
-
-bool Isolate::IsNoElementsProtectorIntact() {
-  return Isolate::IsNoElementsProtectorIntact(context());
-}
-
-bool Isolate::IsIsConcatSpreadableLookupChainIntact() {
-  Cell is_concat_spreadable_cell = heap()->is_concat_spreadable_protector();
-  bool is_is_concat_spreadable_set =
-      Smi::ToInt(is_concat_spreadable_cell.value()) == kProtectorInvalid;
-#ifdef DEBUG
-  Map root_array_map =
-      raw_native_context().GetInitialJSArrayMap(GetInitialFastElementsKind());
-  if (root_array_map.is_null()) {
-    // Ignore the value of is_concat_spreadable during bootstrap.
-    return !is_is_concat_spreadable_set;
-  }
-  Handle<Object> array_prototype(array_function()->prototype(), this);
-  Handle<Symbol> key = factory()->is_concat_spreadable_symbol();
-  Handle<Object> value;
-  LookupIterator it(this, array_prototype, key);
-  if (it.IsFound() && !JSReceiver::GetDataProperty(&it)->IsUndefined(this)) {
-    // TODO(cbruni): Currently we do not revert if we unset the
-    // @@isConcatSpreadable property on Array.prototype or Object.prototype
-    // hence the reverse implication doesn't hold.
-    DCHECK(is_is_concat_spreadable_set);
-    return false;
-  }
-#endif  // DEBUG
-
-  return !is_is_concat_spreadable_set;
-}
-
-bool Isolate::IsIsConcatSpreadableLookupChainIntact(JSReceiver receiver) {
-  if (!IsIsConcatSpreadableLookupChainIntact()) return false;
-  return !receiver.HasProxyInPrototype(this);
-}
-
-bool Isolate::IsPromiseHookProtectorIntact() {
-  PropertyCell promise_hook_cell = heap()->promise_hook_protector();
-  bool is_promise_hook_protector_intact =
-      Smi::ToInt(promise_hook_cell.value()) == kProtectorValid;
-  DCHECK_IMPLIES(is_promise_hook_protector_intact,
-                 !promise_hook_or_async_event_delegate_);
-  DCHECK_IMPLIES(is_promise_hook_protector_intact,
-                 !promise_hook_or_debug_is_active_or_async_event_delegate_);
-  return is_promise_hook_protector_intact;
-}
-
-bool Isolate::IsPromiseResolveLookupChainIntact() {
-  Cell promise_resolve_cell = heap()->promise_resolve_protector();
-  bool is_promise_resolve_protector_intact =
-      Smi::ToInt(promise_resolve_cell.value()) == kProtectorValid;
-  return is_promise_resolve_protector_intact;
-}
-
-bool Isolate::IsPromiseThenLookupChainIntact() {
-  PropertyCell promise_then_cell = heap()->promise_then_protector();
-  bool is_promise_then_protector_intact =
-      Smi::ToInt(promise_then_cell.value()) == kProtectorValid;
-  return is_promise_then_protector_intact;
-}
-
-bool Isolate::IsPromiseThenLookupChainIntact(Handle<JSReceiver> receiver) {
-  DisallowHeapAllocation no_gc;
-  if (!receiver->IsJSPromise()) return false;
-  if (!IsInAnyContext(receiver->map().prototype(),
-                      Context::PROMISE_PROTOTYPE_INDEX)) {
-    return false;
-  }
-  return IsPromiseThenLookupChainIntact();
-}
-
 void Isolate::UpdateNoElementsProtectorOnSetElement(Handle<JSObject> object) {
   DisallowHeapAllocation no_gc;
   if (!object->map().is_prototype_map()) return;
-  if (!IsNoElementsProtectorIntact()) return;
+  if (!Protectors::IsNoElementsIntact(this)) return;
   if (!IsArrayOrObjectOrStringPrototype(*object)) return;
-  PropertyCell::SetValueWithInvalidation(
-      this, "no_elements_protector", factory()->no_elements_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-}
-
-void Isolate::TraceProtectorInvalidation(const char* protector_name) {
-  static constexpr char kInvalidateProtectorTracingCategory[] =
-      "V8.InvalidateProtector";
-  static constexpr char kInvalidateProtectorTracingArg[] = "protector-name";
-
-  DCHECK(FLAG_trace_protector_invalidation);
-
-  // TODO(jgruber): Remove the PrintF once tracing can output to stdout.
-  i::PrintF("Invalidating protector cell %s in isolate %p\n", protector_name,
-            this);
-  TRACE_EVENT_INSTANT1("v8", kInvalidateProtectorTracingCategory,
-                       TRACE_EVENT_SCOPE_THREAD, kInvalidateProtectorTracingArg,
-                       protector_name);
-}
-
-void Isolate::InvalidateIsConcatSpreadableProtector() {
-  DCHECK(factory()->is_concat_spreadable_protector()->value().IsSmi());
-  DCHECK(IsIsConcatSpreadableLookupChainIntact());
-  if (FLAG_trace_protector_invalidation) {
-    TraceProtectorInvalidation("is_concat_spreadable_protector");
-  }
-  factory()->is_concat_spreadable_protector()->set_value(
-      Smi::FromInt(kProtectorInvalid));
-  DCHECK(!IsIsConcatSpreadableLookupChainIntact());
-}
-
-void Isolate::InvalidateArrayConstructorProtector() {
-  DCHECK(factory()->array_constructor_protector()->value().IsSmi());
-  DCHECK(IsArrayConstructorIntact());
-  if (FLAG_trace_protector_invalidation) {
-    TraceProtectorInvalidation("array_constructor_protector");
-  }
-  factory()->array_constructor_protector()->set_value(
-      Smi::FromInt(kProtectorInvalid));
-  DCHECK(!IsArrayConstructorIntact());
-}
-
-void Isolate::InvalidateTypedArraySpeciesProtector() {
-  DCHECK(factory()->typed_array_species_protector()->value().IsSmi());
-  DCHECK(IsTypedArraySpeciesLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "typed_array_species_protector",
-      factory()->typed_array_species_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsTypedArraySpeciesLookupChainIntact());
-}
-
-void Isolate::InvalidatePromiseSpeciesProtector() {
-  DCHECK(factory()->promise_species_protector()->value().IsSmi());
-  DCHECK(IsPromiseSpeciesLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "promise_species_protector", factory()->promise_species_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsPromiseSpeciesLookupChainIntact());
-}
-
-void Isolate::InvalidateStringLengthOverflowProtector() {
-  DCHECK(factory()->string_length_protector()->value().IsSmi());
-  DCHECK(IsStringLengthOverflowIntact());
-  if (FLAG_trace_protector_invalidation) {
-    TraceProtectorInvalidation("string_length_protector");
-  }
-  factory()->string_length_protector()->set_value(
-      Smi::FromInt(kProtectorInvalid));
-  DCHECK(!IsStringLengthOverflowIntact());
-}
-
-void Isolate::InvalidateArrayIteratorProtector() {
-  DCHECK(factory()->array_iterator_protector()->value().IsSmi());
-  DCHECK(IsArrayIteratorLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "array_iterator_protector", factory()->array_iterator_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsArrayIteratorLookupChainIntact());
-}
-
-void Isolate::InvalidateMapIteratorProtector() {
-  DCHECK(factory()->map_iterator_protector()->value().IsSmi());
-  DCHECK(IsMapIteratorLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "map_iterator_protector", factory()->map_iterator_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsMapIteratorLookupChainIntact());
-}
-
-void Isolate::InvalidateSetIteratorProtector() {
-  DCHECK(factory()->set_iterator_protector()->value().IsSmi());
-  DCHECK(IsSetIteratorLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "set_iterator_protector", factory()->set_iterator_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsSetIteratorLookupChainIntact());
-}
-
-void Isolate::InvalidateStringIteratorProtector() {
-  DCHECK(factory()->string_iterator_protector()->value().IsSmi());
-  DCHECK(IsStringIteratorLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "string_iterator_protector", factory()->string_iterator_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsStringIteratorLookupChainIntact());
-}
-
-void Isolate::InvalidateArrayBufferDetachingProtector() {
-  DCHECK(factory()->array_buffer_detaching_protector()->value().IsSmi());
-  DCHECK(IsArrayBufferDetachingIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "array_buffer_detaching_protector",
-      factory()->array_buffer_detaching_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsArrayBufferDetachingIntact());
-}
-
-void Isolate::InvalidatePromiseHookProtector() {
-  DCHECK(factory()->promise_hook_protector()->value().IsSmi());
-  DCHECK(IsPromiseHookProtectorIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "promise_hook_protector", factory()->promise_hook_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsPromiseHookProtectorIntact());
-}
-
-void Isolate::InvalidatePromiseResolveProtector() {
-  DCHECK(factory()->promise_resolve_protector()->value().IsSmi());
-  DCHECK(IsPromiseResolveLookupChainIntact());
-  if (FLAG_trace_protector_invalidation) {
-    TraceProtectorInvalidation("promise_resolve_protector");
-  }
-  factory()->promise_resolve_protector()->set_value(
-      Smi::FromInt(kProtectorInvalid));
-  DCHECK(!IsPromiseResolveLookupChainIntact());
-}
-
-void Isolate::InvalidatePromiseThenProtector() {
-  DCHECK(factory()->promise_then_protector()->value().IsSmi());
-  DCHECK(IsPromiseThenLookupChainIntact());
-  PropertyCell::SetValueWithInvalidation(
-      this, "promise_then_protector", factory()->promise_then_protector(),
-      handle(Smi::FromInt(kProtectorInvalid), this));
-  DCHECK(!IsPromiseThenLookupChainIntact());
+  Protectors::InvalidateNoElements(this);
 }
 
 bool Isolate::IsAnyInitialArrayPrototype(Handle<JSArray> array) {
@@ -4256,9 +3952,9 @@ void Isolate::PromiseHookStateUpdated() {
   bool promise_hook_or_debug_is_active_or_async_event_delegate =
       promise_hook_or_async_event_delegate || debug()->is_active();
   if (promise_hook_or_debug_is_active_or_async_event_delegate &&
-      IsPromiseHookProtectorIntact()) {
+      Protectors::IsPromiseHookIntact(this)) {
     HandleScope scope(this);
-    InvalidatePromiseHookProtector();
+    Protectors::InvalidatePromiseHook(this);
   }
   promise_hook_or_async_event_delegate_ = promise_hook_or_async_event_delegate;
   promise_hook_or_debug_is_active_or_async_event_delegate_ =
@@ -4584,6 +4280,15 @@ void Isolate::AddDetachedContext(Handle<Context> context) {
   heap()->set_detached_contexts(*detached_contexts);
 }
 
+void Isolate::AddSharedWasmMemory(Handle<WasmMemoryObject> memory_object) {
+  HandleScope scope(this);
+  Handle<WeakArrayList> shared_wasm_memories =
+      factory()->shared_wasm_memories();
+  shared_wasm_memories = WeakArrayList::AddToEnd(
+      this, shared_wasm_memories, MaybeObjectHandle::Weak(memory_object));
+  heap()->set_shared_wasm_memories(*shared_wasm_memories);
+}
+
 void Isolate::CheckDetachedContextsAfterGC() {
   HandleScope scope(this);
   Handle<WeakArrayList> detached_contexts = factory()->detached_contexts();