Make assertion scopes thread safe.

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 550 matching lines @@
   RUNTIME_ASSERT(name->IsString() || name->IsUndefined());
   Symbol* symbol;
   MaybeObject* maybe = isolate->heap()->AllocateSymbol();
   if (!maybe->To(&symbol)) return maybe;
   if (name->IsString()) symbol->set_name(*name);
   return symbol;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SymbolName) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(Symbol, symbol, 0);
   return symbol->name();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CreateJSProxy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSReceiver, handler, 0);
   Object* prototype = args[1];
   Object* used_prototype =
       prototype->IsJSReceiver() ? prototype : isolate->heap()->null_value();
   return isolate->heap()->AllocateJSProxy(handler, used_prototype);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CreateJSFunctionProxy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 4);
   CONVERT_ARG_CHECKED(JSReceiver, handler, 0);
   Object* call_trap = args[1];
   RUNTIME_ASSERT(call_trap->IsJSFunction() || call_trap->IsJSFunctionProxy());
   CONVERT_ARG_CHECKED(JSFunction, construct_trap, 2);
   Object* prototype = args[3];
   Object* used_prototype =
       prototype->IsJSReceiver() ? prototype : isolate->heap()->null_value();
   return isolate->heap()->AllocateJSFunctionProxy(
       handler, call_trap, construct_trap, used_prototype);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsJSProxy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   return isolate->heap()->ToBoolean(obj->IsJSProxy());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsJSFunctionProxy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   return isolate->heap()->ToBoolean(obj->IsJSFunctionProxy());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetHandler) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSProxy, proxy, 0);
   return proxy->handler();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetCallTrap) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSFunctionProxy, proxy, 0);
   return proxy->call_trap();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetConstructTrap) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSFunctionProxy, proxy, 0);
   return proxy->construct_trap();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Fix) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSProxy, proxy, 0);
   proxy->Fix();
   return isolate->heap()->undefined_value();
 }
 
 
 static void ArrayBufferWeakCallback(v8::Isolate* external_isolate,
                                     Persistent<Value>* object,
                                     void* data) {
@@ skipping 88 matching lines @@
       return isolate->Throw(*isolate->factory()->
           NewRangeError("invalid_array_buffer_length",
             HandleVector<Object>(NULL, 0)));
   }
 
   return *holder;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ArrayBufferGetByteLength) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSArrayBuffer, holder, 0);
   return holder->byte_length();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ArrayBufferSliceImpl) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, source, 0);
@@ skipping 423 matching lines @@
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
   Handle<Object> value(args[2], isolate);
   Handle<ObjectHashTable> table(ObjectHashTable::cast(weakmap->table()));
   Handle<ObjectHashTable> new_table = PutIntoObjectHashTable(table, key, value);
   weakmap->set_table(*new_table);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ClassOf) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   if (!obj->IsJSObject()) return isolate->heap()->null_value();
   return JSObject::cast(obj)->class_name();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPrototype) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(Object, obj, 0);
   // We don't expect access checks to be needed on JSProxy objects.
   ASSERT(!obj->IsAccessCheckNeeded() || obj->IsJSObject());
   do {
     if (obj->IsAccessCheckNeeded() &&
         !isolate->MayNamedAccess(JSObject::cast(obj),
                                  isolate->heap()->proto_string(),
                                  v8::ACCESS_GET)) {
       isolate->ReportFailedAccessCheck(JSObject::cast(obj), v8::ACCESS_GET);
@@ skipping 11 matching lines @@
   Object* current = receiver->GetPrototype(isolate);
   while (current->IsJSObject() &&
          JSObject::cast(current)->map()->is_hidden_prototype()) {
     current = current->GetPrototype(isolate);
   }
   return current;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetPrototype) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   CONVERT_ARG_CHECKED(Object, prototype, 1);
   if (FLAG_harmony_observation && obj->map()->is_observed()) {
     HandleScope scope(isolate);
     Handle<JSObject> receiver(obj);
     Handle<Object> value(prototype, isolate);
     Handle<Object> old_value(
         GetPrototypeSkipHiddenPrototypes(isolate, *receiver), isolate);
 
     MaybeObject* result = receiver->SetPrototype(*value, true);
     Handle<Object> hresult;
     if (!result->ToHandle(&hresult, isolate)) return result;
 
     Handle<Object> new_value(
         GetPrototypeSkipHiddenPrototypes(isolate, *receiver), isolate);
     if (!new_value->SameValue(*old_value)) {
       JSObject::EnqueueChangeRecord(receiver, "prototype",
                                     isolate->factory()->proto_string(),
                                     old_value);
     }
     return *hresult;
   }
   return obj->SetPrototype(prototype, true);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsInPrototypeChain) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   // See ECMA-262, section 15.3.5.3, page 88 (steps 5 - 8).
   Object* O = args[0];
   Object* V = args[1];
   while (true) {
     Object* prototype = V->GetPrototype(isolate);
     if (prototype->IsNull()) return isolate->heap()->false_value();
     if (O == prototype) return isolate->heap()->true_value();
     V = prototype;
   }
@@ skipping 172 matching lines @@
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetOwnProperty) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, obj, 0);
   CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
   return GetOwnProperty(isolate, obj, name);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PreventExtensions) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   return obj->PreventExtensions();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsExtensible) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   if (obj->IsJSGlobalProxy()) {
     Object* proto = obj->GetPrototype();
     if (proto->IsNull()) return isolate->heap()->false_value();
     ASSERT(proto->IsJSGlobalObject());
     obj = JSObject::cast(proto);
   }
   return isolate->heap()->ToBoolean(obj->map()->is_extensible());
 }
@@ skipping 14 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CreateApiFunction) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(FunctionTemplateInfo, data, 0);
   return *isolate->factory()->CreateApiFunction(data);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsTemplate) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* arg = args[0];
   bool result = arg->IsObjectTemplateInfo() || arg->IsFunctionTemplateInfo();
   return isolate->heap()->ToBoolean(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetTemplateField) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(HeapObject, templ, 0);
   CONVERT_SMI_ARG_CHECKED(index, 1)
   int offset = index * kPointerSize + HeapObject::kHeaderSize;
   InstanceType type = templ->map()->instance_type();
   RUNTIME_ASSERT(type ==  FUNCTION_TEMPLATE_INFO_TYPE ||
                  type ==  OBJECT_TEMPLATE_INFO_TYPE);
   RUNTIME_ASSERT(offset > 0);
   if (type == FUNCTION_TEMPLATE_INFO_TYPE) {
     RUNTIME_ASSERT(offset < FunctionTemplateInfo::kSize);
   } else {
     RUNTIME_ASSERT(offset < ObjectTemplateInfo::kSize);
   }
   return *HeapObject::RawField(templ, offset);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DisableAccessChecks) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(HeapObject, object, 0);
   Map* old_map = object->map();
   bool needs_access_checks = old_map->is_access_check_needed();
   if (needs_access_checks) {
     // Copy map so it won't interfere constructor's initial map.
     Map* new_map;
     MaybeObject* maybe_new_map = old_map->Copy();
     if (!maybe_new_map->To(&new_map)) return maybe_new_map;
 
     new_map->set_is_access_check_needed(false);
     object->set_map(new_map);
   }
   return isolate->heap()->ToBoolean(needs_access_checks);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_EnableAccessChecks) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(HeapObject, object, 0);
   Map* old_map = object->map();
   if (!old_map->is_access_check_needed()) {
     // Copy map so it won't interfere constructor's initial map.
     Map* new_map;
     MaybeObject* maybe_new_map = old_map->Copy();
     if (!maybe_new_map->To(&new_map)) return maybe_new_map;
 
     new_map->set_is_access_check_needed(true);
@@ skipping 212 matching lines @@
       RETURN_IF_EMPTY_HANDLE(isolate,
          JSReceiver::SetProperty(object, name, value, mode, kNonStrictMode));
     }
   }
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeVarGlobal) {
-  NoHandleAllocation nha(isolate);
+  SealHandleScope shs(isolate);
   // args[0] == name
   // args[1] == language_mode
   // args[2] == value (optional)
 
   // Determine if we need to assign to the variable if it already
   // exists (based on the number of arguments).
   RUNTIME_ASSERT(args.length() == 2 || args.length() == 3);
   bool assign = args.length() == 3;
 
   CONVERT_ARG_HANDLE_CHECKED(String, name, 0);
@@ skipping 35 matching lines @@
   // Reload global in case the loop above performed a GC.
   global = isolate->context()->global_object();
   if (assign) {
     return global->SetProperty(*name, args[2], attributes, strict_mode_flag);
   }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeConstGlobal) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   // All constants are declared with an initial value. The name
   // of the constant is the first argument and the initial value
   // is the second.
   RUNTIME_ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(String, name, 0);
   Handle<Object> value = args.at<Object>(1);
 
   // Get the current global object from top.
   GlobalObject* global = isolate->context()->global_object();
 
@@ skipping 185 matching lines @@
   Handle<Object> result = RegExpImpl::Exec(regexp,
                                            subject,
                                            index,
                                            last_match_info);
   if (result.is_null()) return Failure::Exception();
   return *result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpConstructResult) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   CONVERT_SMI_ARG_CHECKED(elements_count, 0);
   if (elements_count < 0 ||
       elements_count > FixedArray::kMaxLength ||
       !Smi::IsValid(elements_count)) {
     return isolate->ThrowIllegalOperation();
   }
   Object* new_object;
   { MaybeObject* maybe_new_object =
         isolate->heap()->AllocateFixedArrayWithHoles(elements_count);
     if (!maybe_new_object->ToObject(&new_object)) return maybe_new_object;
   }
   FixedArray* elements = FixedArray::cast(new_object);
   { MaybeObject* maybe_new_object = isolate->heap()->AllocateRaw(
       JSRegExpResult::kSize, NEW_SPACE, OLD_POINTER_SPACE);
     if (!maybe_new_object->ToObject(&new_object)) return maybe_new_object;
   }
   {
-    AssertNoAllocation no_gc;
+    DisallowHeapAllocation no_gc;
     HandleScope scope(isolate);
     reinterpret_cast<HeapObject*>(new_object)->
         set_map(isolate->native_context()->regexp_result_map());
   }
   JSArray* array = JSArray::cast(new_object);
   array->set_properties(isolate->heap()->empty_fixed_array());
   array->set_elements(elements);
   array->set_length(Smi::FromInt(elements_count));
   // Write in-object properties after the length of the array.
   array->InObjectPropertyAtPut(JSRegExpResult::kIndexIndex, args[1]);
   array->InObjectPropertyAtPut(JSRegExpResult::kInputIndex, args[2]);
   return array;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpInitializeObject) {
-  NoHandleAllocation ha(isolate);
-  AssertNoAllocation no_alloc;
+  SealHandleScope shs(isolate);
+  DisallowHeapAllocation no_allocation;
   ASSERT(args.length() == 5);
   CONVERT_ARG_CHECKED(JSRegExp, regexp, 0);
   CONVERT_ARG_CHECKED(String, source, 1);
   // If source is the empty string we set it to "(?:)" instead as
   // suggested by ECMA-262, 5th, section 15.10.4.1.
   if (source->length() == 0) source = isolate->heap()->query_colon_string();
 
   Object* global = args[2];
   if (!global->IsTrue()) global = isolate->heap()->false_value();
 
@@ skipping 98 matching lines @@
   InstallBuiltin(isolate, holder, "unshift", Builtins::kArrayUnshift);
   InstallBuiltin(isolate, holder, "slice", Builtins::kArraySlice);
   InstallBuiltin(isolate, holder, "splice", Builtins::kArraySplice);
   InstallBuiltin(isolate, holder, "concat", Builtins::kArrayConcat);
 
   return *holder;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsClassicModeFunction) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSReceiver, callable, 0);
   if (!callable->IsJSFunction()) {
     HandleScope scope(isolate);
     bool threw = false;
     Handle<Object> delegate =
         Execution::TryGetFunctionDelegate(Handle<JSReceiver>(callable), &threw);
     if (threw) return Failure::Exception();
     callable = JSFunction::cast(*delegate);
   }
   JSFunction* function = JSFunction::cast(callable);
   SharedFunctionInfo* shared = function->shared();
   return isolate->heap()->ToBoolean(shared->is_classic_mode());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetDefaultReceiver) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSReceiver, callable, 0);
 
   if (!callable->IsJSFunction()) {
     HandleScope scope(isolate);
     bool threw = false;
     Handle<Object> delegate =
         Execution::TryGetFunctionDelegate(Handle<JSReceiver>(callable), &threw);
     if (threw) return Failure::Exception();
     callable = JSFunction::cast(*delegate);
@@ skipping 37 matching lines @@
   if (has_pending_exception) {
     ASSERT(isolate->has_pending_exception());
     return Failure::Exception();
   }
   literals->set(index, *regexp);
   return *regexp;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetName) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return f->shared()->name();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetName) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   CONVERT_ARG_CHECKED(String, name, 1);
   f->shared()->set_name(name);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionNameShouldPrintAsAnonymous) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(
       f->shared()->name_should_print_as_anonymous());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionMarkNameShouldPrintAsAnonymous) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   f->shared()->set_name_should_print_as_anonymous(true);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsGenerator) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(f->shared()->is_generator());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionRemovePrototype) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   f->RemovePrototype();
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetScript) {
@@ skipping 12 matching lines @@
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, f, 0);
   Handle<SharedFunctionInfo> shared(f->shared());
   return *shared->GetSourceCode();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetScriptSourcePosition) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, fun, 0);
   int pos = fun->shared()->start_position();
   return Smi::FromInt(pos);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetPositionForOffset) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(Code, code, 0);
   CONVERT_NUMBER_CHECKED(int, offset, Int32, args[1]);
 
   RUNTIME_ASSERT(0 <= offset && offset < code->Size());
 
   Address pc = code->address() + offset;
   return Smi::FromInt(code->SourcePosition(pc));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetInstanceClassName) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSFunction, fun, 0);
   CONVERT_ARG_CHECKED(String, name, 1);
   fun->SetInstanceClassName(name);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetLength) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSFunction, fun, 0);
   CONVERT_SMI_ARG_CHECKED(length, 1);
   fun->shared()->set_length(length);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetPrototype) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSFunction, fun, 0);
   ASSERT(fun->should_have_prototype());
   Object* obj;
   { MaybeObject* maybe_obj =
         Accessors::FunctionSetPrototype(fun, args[1], NULL);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   return args[0];  // return TOS
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionSetReadOnlyPrototype) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSFunction, function, 0);
 
   String* name = isolate->heap()->prototype_string();
 
   if (function->HasFastProperties()) {
     // Construct a new field descriptor with updated attributes.
     DescriptorArray* instance_desc = function->map()->instance_descriptors();
 
     int index = instance_desc->SearchWithCache(name, function->map());
@@ skipping 21 matching lines @@
         static_cast<PropertyAttributes>(details.attributes() | READ_ONLY),
         details.type(),
         details.dictionary_index());
     function->property_dictionary()->DetailsAtPut(entry, new_details);
   }
   return function;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsAPIFunction) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(f->shared()->IsApiFunction());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsBuiltin) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(f->IsBuiltin());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetCode) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
@@ skipping 69 matching lines @@
   ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   CONVERT_SMI_ARG_CHECKED(num, 1);
   RUNTIME_ASSERT(num >= 0);
   SetExpectedNofProperties(function, num);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CreateJSGeneratorObject) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
 
   JavaScriptFrameIterator it(isolate);
   JavaScriptFrame* frame = it.frame();
   JSFunction* function = JSFunction::cast(frame->function());
   RUNTIME_ASSERT(function->shared()->is_generator());
 
   JSGeneratorObject* generator;
   if (frame->IsConstructor()) {
     generator = JSGeneratorObject::cast(frame->receiver());
   } else {
     MaybeObject* maybe_generator =
         isolate->heap()->AllocateJSGeneratorObject(function);
     if (!maybe_generator->To(&generator)) return maybe_generator;
   }
   generator->set_function(function);
   generator->set_context(Context::cast(frame->context()));
   generator->set_receiver(frame->receiver());
   generator->set_continuation(0);
   generator->set_operand_stack(isolate->heap()->empty_fixed_array());
   generator->set_stack_handler_index(-1);
 
   return generator;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SuspendJSGeneratorObject) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSGeneratorObject, generator_object, 0);
 
   JavaScriptFrameIterator stack_iterator(isolate);
   JavaScriptFrame* frame = stack_iterator.frame();
   JSFunction* function = JSFunction::cast(frame->function());
   RUNTIME_ASSERT(function->shared()->is_generator());
   ASSERT_EQ(function, generator_object->function());
 
   // We expect there to be at least two values on the operand stack: the return
@@ skipping 38 matching lines @@
 
 
 // Note that this function is the slow path for resuming generators.  It is only
 // called if the suspended activation had operands on the stack, stack handlers
 // needing rewinding, or if the resume should throw an exception.  The fast path
 // is handled directly in FullCodeGenerator::EmitGeneratorResume(), which is
 // inlined into GeneratorNext, GeneratorSend, and GeneratorThrow.
 // EmitGeneratorResumeResume is called in any case, as it needs to reconstruct
 // the stack frame and make space for arguments and operands.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ResumeJSGeneratorObject) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_CHECKED(JSGeneratorObject, generator_object, 0);
   CONVERT_ARG_CHECKED(Object, value, 1);
   CONVERT_SMI_ARG_CHECKED(resume_mode_int, 2);
   JavaScriptFrameIterator stack_iterator(isolate);
   JavaScriptFrame* frame = stack_iterator.frame();
 
   ASSERT_EQ(frame->function(), generator_object->function());
 
   STATIC_ASSERT(JSGeneratorObject::kGeneratorExecuting <= 0);
@@ skipping 35 matching lines @@
   int continuation = generator->continuation();
   const char* message = continuation == JSGeneratorObject::kGeneratorClosed ?
       "generator_finished" : "generator_running";
   Vector< Handle<Object> > argv = HandleVector<Object>(NULL, 0);
   Handle<Object> error = isolate->factory()->NewError(message, argv);
   return isolate->Throw(*error);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectFreeze) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, object, 0);
   return object->Freeze(isolate);
 }
 
 
 MUST_USE_RESULT static MaybeObject* CharFromCode(Isolate* isolate,
                                                  Object* char_code) {
   if (char_code->IsNumber()) {
     return isolate->heap()->LookupSingleCharacterStringFromCode(
         NumberToUint32(char_code) & 0xffff);
   }
   return isolate->heap()->empty_string();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringCharCodeAt) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(String, subject, 0);
   CONVERT_NUMBER_CHECKED(uint32_t, i, Uint32, args[1]);
 
   // Flatten the string.  If someone wants to get a char at an index
   // in a cons string, it is likely that more indices will be
   // accessed.
   Object* flat;
   { MaybeObject* maybe_flat = subject->TryFlatten();
     if (!maybe_flat->ToObject(&flat)) return maybe_flat;
   }
   subject = String::cast(flat);
 
   if (i >= static_cast<uint32_t>(subject->length())) {
     return isolate->heap()->nan_value();
   }
 
   return Smi::FromInt(subject->Get(i));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CharFromCode) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   return CharFromCode(isolate, args[0]);
 }
 
 
 class FixedArrayBuilder {
  public:
   explicit FixedArrayBuilder(Isolate* isolate, int initial_capacity)
       : array_(isolate->factory()->NewFixedArrayWithHoles(initial_capacity)),
         length_(0),
@@ skipping 149 matching lines @@
 
 
   Handle<String> ToString() {
     if (array_builder_.length() == 0) {
       return heap_->isolate()->factory()->empty_string();
     }
 
     Handle<String> joined_string;
     if (is_ascii_) {
       Handle<SeqOneByteString> seq = NewRawOneByteString(character_count_);
-      AssertNoAllocation no_alloc;
+      DisallowHeapAllocation no_gc;
       uint8_t* char_buffer = seq->GetChars();
       StringBuilderConcatHelper(*subject_,
                                 char_buffer,
                                 *array_builder_.array(),
                                 array_builder_.length());
       joined_string = Handle<String>::cast(seq);
     } else {
       // Non-ASCII.
       Handle<SeqTwoByteString> seq = NewRawTwoByteString(character_count_);
-      AssertNoAllocation no_alloc;
+      DisallowHeapAllocation no_gc;
       uc16* char_buffer = seq->GetChars();
       StringBuilderConcatHelper(*subject_,
                                 char_buffer,
                                 *array_builder_.array(),
                                 array_builder_.length());
       joined_string = Handle<String>::cast(seq);
     }
     return joined_string;
   }
 
@@ skipping 221 matching lines @@
   ZoneList<ReplacementPart> parts_;
   ZoneList<Handle<String> > replacement_substrings_;
   Zone* zone_;
 };
 
 
 bool CompiledReplacement::Compile(Handle<String> replacement,
                                   int capture_count,
                                   int subject_length) {
   {
-    AssertNoAllocation no_alloc;
+    DisallowHeapAllocation no_gc;
     String::FlatContent content = replacement->GetFlatContent();
     ASSERT(content.IsFlat());
     bool simple = false;
     if (content.IsAscii()) {
       simple = ParseReplacementPattern(&parts_,
                                        content.ToOneByteVector(),
                                        capture_count,
                                        subject_length,
                                        zone());
     } else {
@@ skipping 130 matching lines @@
 }
 
 
 void FindStringIndicesDispatch(Isolate* isolate,
                                String* subject,
                                String* pattern,
                                ZoneList<int>* indices,
                                unsigned int limit,
                                Zone* zone) {
   {
-    AssertNoAllocation no_gc;
+    DisallowHeapAllocation no_gc;
     String::FlatContent subject_content = subject->GetFlatContent();
     String::FlatContent pattern_content = pattern->GetFlatContent();
     ASSERT(subject_content.IsFlat());
     ASSERT(pattern_content.IsFlat());
     if (subject_content.IsAscii()) {
       Vector<const uint8_t> subject_vector = subject_content.ToOneByteVector();
       if (pattern_content.IsAscii()) {
         Vector<const uint8_t> pattern_vector =
             pattern_content.ToOneByteVector();
         if (pattern_vector.length() == 1) {
@@ skipping 448 matching lines @@
 
   int pattern_length = pat->length();
   if (pattern_length == 0) return start_index;
 
   int subject_length = sub->length();
   if (start_index + pattern_length > subject_length) return -1;
 
   if (!sub->IsFlat()) FlattenString(sub);
   if (!pat->IsFlat()) FlattenString(pat);
 
-  AssertNoAllocation no_heap_allocation;  // ensure vectors stay valid
+  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
   // Extract flattened substrings of cons strings before determining asciiness.
   String::FlatContent seq_sub = sub->GetFlatContent();
   String::FlatContent seq_pat = pat->GetFlatContent();
 
   // dispatch on type of strings
   if (seq_pat.IsAscii()) {
     Vector<const uint8_t> pat_vector = seq_pat.ToOneByteVector();
     if (seq_sub.IsAscii()) {
       return SearchString(isolate,
                           seq_sub.ToOneByteVector(),
@@ skipping 90 matching lines @@
   }
 
   if (pat_length == 0) {
     return Smi::FromInt(start_index);
   }
 
   if (!sub->IsFlat()) FlattenString(sub);
   if (!pat->IsFlat()) FlattenString(pat);
 
   int position = -1;
-  AssertNoAllocation no_heap_allocation;  // ensure vectors stay valid
+  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
 
   String::FlatContent sub_content = sub->GetFlatContent();
   String::FlatContent pat_content = pat->GetFlatContent();
 
   if (pat_content.IsAscii()) {
     Vector<const uint8_t> pat_vector = pat_content.ToOneByteVector();
     if (sub_content.IsAscii()) {
       position = StringMatchBackwards(sub_content.ToOneByteVector(),
                                       pat_vector,
                                       start_index);
@@ skipping 13 matching lines @@
                                       pat_vector,
                                       start_index);
     }
   }
 
   return Smi::FromInt(position);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringLocaleCompare) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(String, str1, 0);
   CONVERT_ARG_CHECKED(String, str2, 1);
 
   if (str1 == str2) return Smi::FromInt(0);  // Equal.
   int str1_length = str1->length();
   int str2_length = str2->length();
 
   // Decide trivial cases without flattening.
@@ skipping 27 matching lines @@
     uint16_t char1 = stream1.GetNext();
     uint16_t char2 = stream2.GetNext();
     if (char1 != char2) return Smi::FromInt(char1 - char2);
   }
 
   return Smi::FromInt(str1_length - str2_length);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SubString) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
 
   CONVERT_ARG_CHECKED(String, value, 0);
   int start, end;
   // We have a fast integer-only case here to avoid a conversion to double in
   // the common case where from and to are Smis.
   if (args[1]->IsSmi() && args[2]->IsSmi()) {
     CONVERT_SMI_ARG_CHECKED(from_number, 1);
     CONVERT_SMI_ARG_CHECKED(to_number, 2);
     start = from_number;
@@ skipping 241 matching lines @@
     return SearchRegExpMultiple<false>(
         isolate, subject, regexp, last_match_info, result_array);
   } else {
     return SearchRegExpMultiple<true>(
         isolate, subject, regexp, last_match_info, result_array);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToRadixString) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_SMI_ARG_CHECKED(radix, 1);
   RUNTIME_ASSERT(2 <= radix && radix <= 36);
 
   // Fast case where the result is a one character string.
   if (args[0]->IsSmi()) {
     int value = args.smi_at(0);
     if (value >= 0 && value < radix) {
       // Character array used for conversion.
       static const char kCharTable[] = "0123456789abcdefghijklmnopqrstuvwxyz";
@@ skipping 15 matching lines @@
   }
   char* str = DoubleToRadixCString(value, radix);
   MaybeObject* result =
       isolate->heap()->AllocateStringFromOneByte(CStrVector(str));
   DeleteArray(str);
   return result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToFixed) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(value, 0);
   CONVERT_DOUBLE_ARG_CHECKED(f_number, 1);
   int f = FastD2IChecked(f_number);
   RUNTIME_ASSERT(f >= 0);
   char* str = DoubleToFixedCString(value, f);
   MaybeObject* res =
       isolate->heap()->AllocateStringFromOneByte(CStrVector(str));
   DeleteArray(str);
   return res;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToExponential) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(value, 0);
   CONVERT_DOUBLE_ARG_CHECKED(f_number, 1);
   int f = FastD2IChecked(f_number);
   RUNTIME_ASSERT(f >= -1 && f <= 20);
   char* str = DoubleToExponentialCString(value, f);
   MaybeObject* res =
       isolate->heap()->AllocateStringFromOneByte(CStrVector(str));
   DeleteArray(str);
   return res;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToPrecision) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(value, 0);
   CONVERT_DOUBLE_ARG_CHECKED(f_number, 1);
   int f = FastD2IChecked(f_number);
   RUNTIME_ASSERT(f >= 1 && f <= 21);
   char* str = DoubleToPrecisionCString(value, f);
   MaybeObject* res =
       isolate->heap()->AllocateStringFromOneByte(CStrVector(str));
   DeleteArray(str);
@@ skipping 116 matching lines @@
   // the element if so.
   if (name->AsArrayIndex(&index)) {
     return GetElementOrCharAt(isolate, object, index);
   } else {
     return object->GetProperty(*name);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   Handle<Object> object = args.at<Object>(0);
   Handle<Object> key = args.at<Object>(1);
 
   return Runtime::GetObjectProperty(isolate, object, key);
 }
 
 
 // KeyedGetProperty is called from KeyedLoadIC::GenerateGeneric.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_KeyedGetProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   // Fast cases for getting named properties of the receiver JSObject
   // itself.
   //
   // The global proxy objects has to be excluded since LocalLookup on
   // the global proxy object can return a valid result even though the
   // global proxy object never has properties.  This is the case
   // because the global proxy object forwards everything to its hidden
   // prototype including local lookups.
@@ skipping 187 matching lines @@
   return Runtime::ForceSetObjectProperty(isolate,
                                          js_object,
                                          name,
                                          obj_value,
                                          attr);
 }
 
 
 // Return property without being observable by accessors or interceptors.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetDataProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
   CONVERT_ARG_HANDLE_CHECKED(Name, key, 1);
   LookupResult lookup(isolate);
   object->LookupRealNamedProperty(*key, &lookup);
   if (!lookup.IsFound()) return isolate->heap()->undefined_value();
   switch (lookup.type()) {
     case NORMAL:
       return lookup.holder()->GetNormalizedProperty(&lookup);
     case FIELD:
@@ skipping 192 matching lines @@
     if (has_pending_exception) return Failure::Exception();
     name = Handle<String>::cast(converted);
   }
 
   if (name->IsString()) Handle<String>::cast(name)->TryFlatten();
   return receiver->DeleteProperty(*name, mode);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(args.length() == 4 || args.length() == 5);
 
   Handle<Object> object = args.at<Object>(0);
   Handle<Object> key = args.at<Object>(1);
   Handle<Object> value = args.at<Object>(2);
   CONVERT_SMI_ARG_CHECKED(unchecked_attributes, 3);
   RUNTIME_ASSERT(
       (unchecked_attributes & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
   // Compute attributes.
   PropertyAttributes attributes =
@@ skipping 18 matching lines @@
   HandleScope scope(isolate);
   RUNTIME_ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
   CONVERT_ARG_HANDLE_CHECKED(Map, map, 1);
   JSObject::TransitionElementsKind(array, map->elements_kind());
   return *array;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_TransitionElementsSmiToDouble) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(args.length() == 1);
   Handle<Object> object = args.at<Object>(0);
   if (object->IsJSObject()) {
     Handle<JSObject> js_object(Handle<JSObject>::cast(object));
     ASSERT(!js_object->map()->is_observed());
     ElementsKind new_kind = js_object->HasFastHoleyElements()
         ? FAST_HOLEY_DOUBLE_ELEMENTS
         : FAST_DOUBLE_ELEMENTS;
     return TransitionElements(object, new_kind, isolate);
   } else {
     return *object;
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_TransitionElementsDoubleToObject) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(args.length() == 1);
   Handle<Object> object = args.at<Object>(0);
   if (object->IsJSObject()) {
     Handle<JSObject> js_object(Handle<JSObject>::cast(object));
     ASSERT(!js_object->map()->is_observed());
     ElementsKind new_kind = js_object->HasFastHoleyElements()
         ? FAST_HOLEY_ELEMENTS
         : FAST_ELEMENTS;
     return TransitionElements(object, new_kind, isolate);
   } else {
     return *object;
   }
 }
 
 
 // Set the native flag on the function.
 // This is used to decide if we should transform null and undefined
 // into the global object when doing call and apply.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetNativeFlag) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(args.length() == 1);
 
   Handle<Object> object = args.at<Object>(0);
 
   if (object->IsJSFunction()) {
     JSFunction* func = JSFunction::cast(*object);
     func->shared()->set_native(true);
   }
   return isolate->heap()->undefined_value();
 }
@@ skipping 45 matching lines @@
     FixedArray* object_array = FixedArray::cast(object->elements());
     object_array->set(store_index, *value);
   }
   return *object;
 }
 
 
 // Check whether debugger and is about to step into the callback that is passed
 // to a built-in function such as Array.forEach.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugCallbackSupportsStepping) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   if (!isolate->IsDebuggerActive() || !isolate->debug()->StepInActive()) {
     return isolate->heap()->false_value();
   }
   CONVERT_ARG_CHECKED(Object, callback, 0);
   // We do not step into the callback if it's a builtin or not even a function.
   if (!callback->IsJSFunction() || JSFunction::cast(callback)->IsBuiltin()) {
     return isolate->heap()->false_value();
   }
   return isolate->heap()->true_value();
 #else
   return isolate->heap()->false_value();
 #endif  // ENABLE_DEBUGGER_SUPPORT
 }
 
 
 // Set one shot breakpoints for the callback function that is passed to a
 // built-in function such as Array.forEach to enable stepping into the callback.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPrepareStepInIfStepping) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   Debug* debug = isolate->debug();
   if (!debug->IsStepping()) return isolate->heap()->undefined_value();
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, callback, 0);
   HandleScope scope(isolate);
   // When leaving the callback, step out has been activated, but not performed
   // if we do not leave the builtin.  To be able to step into the callback
   // again, we need to clear the step out at this point.
   debug->ClearStepOut();
   debug->FloodWithOneShot(callback);
 #endif  // ENABLE_DEBUGGER_SUPPORT
   return isolate->heap()->undefined_value();
 }
 
 
 // Set a local property, even if it is READ_ONLY.  If the property does not
 // exist, it will be added with attributes NONE.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IgnoreAttributesAndSetProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(args.length() == 3 || args.length() == 4);
   CONVERT_ARG_CHECKED(JSObject, object, 0);
   CONVERT_ARG_CHECKED(Name, name, 1);
   // Compute attributes.
   PropertyAttributes attributes = NONE;
   if (args.length() == 4) {
     CONVERT_SMI_ARG_CHECKED(unchecked_value, 3);
     // Only attribute bits should be set.
     RUNTIME_ASSERT(
         (unchecked_value & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
     attributes = static_cast<PropertyAttributes>(unchecked_value);
   }
 
   return object->
       SetLocalPropertyIgnoreAttributes(name, args[2], attributes);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DeleteProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
 
   CONVERT_ARG_CHECKED(JSReceiver, object, 0);
   CONVERT_ARG_CHECKED(Name, key, 1);
   CONVERT_STRICT_MODE_ARG_CHECKED(strict_mode, 2);
   return object->DeleteProperty(key, (strict_mode == kStrictMode)
                                       ? JSReceiver::STRICT_DELETION
                                       : JSReceiver::NORMAL_DELETION);
 }
 
@@ skipping 10 matching lines @@
       Handle<JSObject>::cast(proto)->map()->is_hidden_prototype()) {
     return HasLocalPropertyImplementation(isolate,
                                           Handle<JSObject>::cast(proto),
                                           key);
   }
   return isolate->heap()->false_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HasLocalProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(Name, key, 1);
 
   uint32_t index;
   const bool key_is_array_index = key->AsArrayIndex(&index);
 
   Object* obj = args[0];
   // Only JS objects can have properties.
   if (obj->IsJSObject()) {
     JSObject* object = JSObject::cast(obj);
@@ skipping 18 matching lines @@
     String* string = String::cast(obj);
     if (index < static_cast<uint32_t>(string->length())) {
       return isolate->heap()->true_value();
     }
   }
   return isolate->heap()->false_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HasProperty) {
-  NoHandleAllocation na(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSReceiver, receiver, 0);
   CONVERT_ARG_CHECKED(Name, key, 1);
 
   bool result = receiver->HasProperty(key);
   if (isolate->has_pending_exception()) return Failure::Exception();
   return isolate->heap()->ToBoolean(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HasElement) {
-  NoHandleAllocation na(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSReceiver, receiver, 0);
   CONVERT_SMI_ARG_CHECKED(index, 1);
 
   bool result = receiver->HasElement(index);
   if (isolate->has_pending_exception()) return Failure::Exception();
   return isolate->heap()->ToBoolean(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsPropertyEnumerable) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSObject, object, 0);
   CONVERT_ARG_CHECKED(Name, key, 1);
 
   PropertyAttributes att = object->GetLocalPropertyAttribute(key);
   return isolate->heap()->ToBoolean(att != ABSENT && (att & DONT_ENUM) == 0);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPropertyNames) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, object, 0);
   bool threw = false;
   Handle<JSArray> result = GetKeysFor(object, &threw);
   if (threw) return Failure::Exception();
   return *result;
 }
 
 
 // Returns either a FixedArray as Runtime_GetPropertyNames,
 // or, if the given object has an enum cache that contains
 // all enumerable properties of the object and its prototypes
 // have none, the map of the object. This is used to speed up
 // the check for deletions during a for-in.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPropertyNamesFast) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSReceiver, raw_object, 0);
 
   if (raw_object->IsSimpleEnum()) return raw_object->map();
 
   HandleScope scope(isolate);
   Handle<JSReceiver> object(raw_object);
   bool threw = false;
   Handle<FixedArray> content =
@@ skipping 218 matching lines @@
       Handle<Object> entry_str =
           isolate->factory()->NumberToString(entry_handle);
       copy->set(i, *entry_str);
     }
   }
   return *isolate->factory()->NewJSArrayWithElements(copy);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetArgumentsProperty) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   // Compute the frame holding the arguments.
   JavaScriptFrameIterator it(isolate);
   it.AdvanceToArgumentsFrame();
   JavaScriptFrame* frame = it.frame();
 
   // Get the actual number of provided arguments.
   const uint32_t n = frame->ComputeParametersCount();
 
@@ skipping 38 matching lines @@
     }
     return function;
   }
 
   // Lookup in the initial Object.prototype object.
   return isolate->initial_object_prototype()->GetProperty(*key);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ToFastProperties) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* object = args[0];
   return (object->IsJSObject() && !object->IsGlobalObject())
       ? JSObject::cast(object)->TransformToFastProperties(0)
       : object;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ToBool) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   return isolate->heap()->ToBoolean(args[0]->BooleanValue());
 }
 
 
 // Returns the type string of a value; see ECMA-262, 11.4.3 (p 47).
 // Possible optimizations: put the type string into the oddballs.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Typeof) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
 
   Object* obj = args[0];
   if (obj->IsNumber()) return isolate->heap()->number_string();
   HeapObject* heap_obj = HeapObject::cast(obj);
 
   // typeof an undetectable object is 'undefined'
   if (heap_obj->map()->is_undetectable()) {
     return isolate->heap()->undefined_string();
   }
 
@@ skipping 43 matching lines @@
 
   for (int i = from + 1; i < to; i++) {
     d = 10 * d + (s[i] - '0');
   }
 
   return d;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringToNumber) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(String, subject, 0);
   subject->TryFlatten();
 
   // Fast case: short integer or some sorts of junk values.
   int len = subject->length();
   if (subject->IsSeqOneByteString()) {
     if (len == 0) return Smi::FromInt(0);
 
     uint8_t const* data = SeqOneByteString::cast(subject)->GetChars();
@@ skipping 34 matching lines @@
     }
   }
 
   // Slower case.
   return isolate->heap()->NumberFromDouble(
       StringToDouble(isolate->unicode_cache(), subject, ALLOW_HEX));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewString) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   CONVERT_SMI_ARG_CHECKED(length, 0);
   CONVERT_BOOLEAN_ARG_CHECKED(is_one_byte, 1);
   if (length == 0) return isolate->heap()->empty_string();
   if (is_one_byte) {
     return isolate->heap()->AllocateRawOneByteString(length);
   } else {
     return isolate->heap()->AllocateRawTwoByteString(length);
   }
 }
 
@@ skipping 42 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_BasicJSONStringify) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   BasicJsonStringifier stringifier(isolate);
   return stringifier.Stringify(Handle<Object>(args[0], isolate));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringParseInt) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
 
   CONVERT_ARG_CHECKED(String, s, 0);
   CONVERT_SMI_ARG_CHECKED(radix, 1);
 
   s->TryFlatten();
 
   RUNTIME_ASSERT(radix == 0 || (2 <= radix && radix <= 36));
   double value = StringToInt(isolate->unicode_cache(), s, radix);
   return isolate->heap()->NumberFromDouble(value);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringParseFloat) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   CONVERT_ARG_CHECKED(String, str, 0);
 
   // ECMA-262 section 15.1.2.3, empty string is NaN
   double value = StringToDouble(isolate->unicode_cache(),
                                 str, ALLOW_TRAILING_JUNK, OS::nan_value());
 
   // Create a number object from the value.
   return isolate->heap()->NumberFromDouble(value);
 }
 
@@ skipping 234 matching lines @@
 };
 
 }  // namespace
 
 
 template <typename ConvertTraits>
 MUST_USE_RESULT static MaybeObject* ConvertCase(
     Arguments args,
     Isolate* isolate,
     unibrow::Mapping<typename ConvertTraits::UnibrowConverter, 128>* mapping) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   CONVERT_ARG_CHECKED(String, s, 0);
   s = s->TryFlattenGetString();
 
   const int length = s->length();
   // Assume that the string is not empty; we need this assumption later
   if (length == 0) return s;
 
   // Simpler handling of ASCII strings.
   //
   // NOTE: This assumes that the upper/lower case of an ASCII
@@ skipping 46 matching lines @@
       args, isolate, isolate->runtime_state()->to_upper_mapping());
 }
 
 
 static inline bool IsTrimWhiteSpace(unibrow::uchar c) {
   return unibrow::WhiteSpace::Is(c) || c == 0x200b || c == 0xfeff;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringTrim) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
 
   CONVERT_ARG_CHECKED(String, s, 0);
   CONVERT_BOOLEAN_ARG_CHECKED(trimLeft, 1);
   CONVERT_BOOLEAN_ARG_CHECKED(trimRight, 2);
 
   s->TryFlatten();
   int length = s->length();
 
   int left = 0;
@@ skipping 105 matching lines @@
 
 
 // Copies ASCII characters to the given fixed array looking up
 // one-char strings in the cache. Gives up on the first char that is
 // not in the cache and fills the remainder with smi zeros. Returns
 // the length of the successfully copied prefix.
 static int CopyCachedAsciiCharsToArray(Heap* heap,
                                        const uint8_t* chars,
                                        FixedArray* elements,
                                        int length) {
-  AssertNoAllocation no_gc;
+  DisallowHeapAllocation no_gc;
   FixedArray* ascii_cache = heap->single_character_string_cache();
   Object* undefined = heap->undefined_value();
   int i;
   WriteBarrierMode mode = elements->GetWriteBarrierMode(no_gc);
   for (i = 0; i < length; ++i) {
     Object* value = ascii_cache->get(chars[i]);
     if (value == undefined) break;
     elements->set(i, value, mode);
   }
   if (i < length) {
@@ skipping 25 matching lines @@
   Handle<FixedArray> elements;
   int position = 0;
   if (s->IsFlat() && s->IsOneByteRepresentation()) {
     // Try using cached chars where possible.
     Object* obj;
     { MaybeObject* maybe_obj =
           isolate->heap()->AllocateUninitializedFixedArray(length);
       if (!maybe_obj->ToObject(&obj)) return maybe_obj;
     }
     elements = Handle<FixedArray>(FixedArray::cast(obj), isolate);
-    AssertNoAllocation no_gc;
+    DisallowHeapAllocation no_gc;
     String::FlatContent content = s->GetFlatContent();
     if (content.IsAscii()) {
       Vector<const uint8_t> chars = content.ToOneByteVector();
       // Note, this will initialize all elements (not only the prefix)
       // to prevent GC from seeing partially initialized array.
       position = CopyCachedAsciiCharsToArray(isolate->heap(),
                                              chars.start(),
                                              *elements,
                                              length);
     } else {
@@ skipping 14 matching lines @@
   for (int i = 0; i < length; ++i) {
     ASSERT(String::cast(elements->get(i))->length() == 1);
   }
 #endif
 
   return *isolate->factory()->NewJSArrayWithElements(elements);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewStringWrapper) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(String, value, 0);
   return value->ToObject();
 }
 
 
 bool Runtime::IsUpperCaseChar(RuntimeState* runtime_state, uint16_t ch) {
   unibrow::uchar chars[unibrow::ToUppercase::kMaxWidth];
   int char_length = runtime_state->to_upper_mapping()->get(ch, 0, chars);
   return char_length == 0;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToString) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   Object* number = args[0];
   RUNTIME_ASSERT(number->IsNumber());
 
   return isolate->heap()->NumberToString(number);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToStringSkipCache) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   Object* number = args[0];
   RUNTIME_ASSERT(number->IsNumber());
 
   return isolate->heap()->NumberToString(
       number, false, isolate->heap()->GetPretenureMode());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToInteger) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(number, 0);
 
   // We do not include 0 so that we don't have to treat +0 / -0 cases.
   if (number > 0 && number <= Smi::kMaxValue) {
     return Smi::FromInt(static_cast<int>(number));
   }
   return isolate->heap()->NumberFromDouble(DoubleToInteger(number));
 }
 
 
 // ES6 draft 9.1.11
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToPositiveInteger) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(number, 0);
 
   // We do not include 0 so that we don't have to treat +0 / -0 cases.
   if (number > 0 && number <= Smi::kMaxValue) {
     return Smi::FromInt(static_cast<int>(number));
   }
   if (number <= 0) {
     return Smi::FromInt(0);
   }
   return isolate->heap()->NumberFromDouble(DoubleToInteger(number));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToIntegerMapMinusZero) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(number, 0);
 
   // We do not include 0 so that we don't have to treat +0 / -0 cases.
   if (number > 0 && number <= Smi::kMaxValue) {
     return Smi::FromInt(static_cast<int>(number));
   }
 
   double double_value = DoubleToInteger(number);
   // Map both -0 and +0 to +0.
   if (double_value == 0) double_value = 0;
 
   return isolate->heap()->NumberFromDouble(double_value);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToJSUint32) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_NUMBER_CHECKED(int32_t, number, Uint32, args[0]);
   return isolate->heap()->NumberFromUint32(number);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToJSInt32) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(number, 0);
 
   // We do not include 0 so that we don't have to treat +0 / -0 cases.
   if (number > 0 && number <= Smi::kMaxValue) {
     return Smi::FromInt(static_cast<int>(number));
   }
   return isolate->heap()->NumberFromInt32(DoubleToInt32(number));
 }
 
 
 // Converts a Number to a Smi, if possible. Returns NaN if the number is not
 // a small integer.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberToSmi) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   Object* obj = args[0];
   if (obj->IsSmi()) {
     return obj;
   }
   if (obj->IsHeapNumber()) {
     double value = HeapNumber::cast(obj)->value();
     int int_value = FastD2I(value);
     if (value == FastI2D(int_value) && Smi::IsValid(int_value)) {
       return Smi::FromInt(int_value);
     }
   }
   return isolate->heap()->nan_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_AllocateHeapNumber) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   return isolate->heap()->AllocateHeapNumber(0);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberAdd) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   return isolate->heap()->NumberFromDouble(x + y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberSub) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   return isolate->heap()->NumberFromDouble(x - y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberMul) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   return isolate->heap()->NumberFromDouble(x * y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberUnaryMinus) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->heap()->NumberFromDouble(-x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberAlloc) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
 
   return isolate->heap()->NumberFromDouble(9876543210.0);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberDiv) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   return isolate->heap()->NumberFromDouble(x / y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberMod) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
 
   x = modulo(x, y);
   // NumberFromDouble may return a Smi instead of a Number object
   return isolate->heap()->NumberFromDouble(x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberImul) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromInt32(x * y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringAdd) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(String, str1, 0);
   CONVERT_ARG_CHECKED(String, str2, 1);
   isolate->counters()->string_add_runtime()->Increment();
   return isolate->heap()->AllocateConsString(str1, str2);
 }
 
 
 template <typename sinkchar>
 static inline void StringBuilderConcatHelper(String* special,
@@ skipping 28 matching lines @@
       String* string = String::cast(element);
       int element_length = string->length();
       String::WriteToFlat(string, sink + position, 0, element_length);
       position += element_length;
     }
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringBuilderConcat) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_CHECKED(JSArray, array, 0);
   if (!args[1]->IsSmi()) {
     isolate->context()->mark_out_of_memory();
     return Failure::OutOfMemoryException(0x14);
   }
   int array_length = args.smi_at(1);
   CONVERT_ARG_CHECKED(String, special, 2);
 
   // This assumption is used by the slice encoding in one or two smis.
@@ skipping 96 matching lines @@
     StringBuilderConcatHelper(special,
                               answer->GetChars(),
                               fixed_array,
                               array_length);
     return answer;
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringBuilderJoin) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_CHECKED(JSArray, array, 0);
   if (!args[1]->IsSmi()) {
     isolate->context()->mark_out_of_memory();
     return Failure::OutOfMemoryException(0x16);
   }
   int array_length = args.smi_at(1);
   CONVERT_ARG_CHECKED(String, separator, 2);
 
   if (!array->HasFastObjectElements()) {
@@ skipping 104 matching lines @@
                                 0, separator_length);
       cursor += separator_length;
       previous_separator_position++;
     }
   }
   ASSERT(cursor <= buffer.length());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SparseJoinWithSeparator) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_CHECKED(JSArray, elements_array, 0);
   RUNTIME_ASSERT(elements_array->HasFastSmiOrObjectElements());
   CONVERT_NUMBER_CHECKED(uint32_t, array_length, Uint32, args[1]);
   CONVERT_ARG_CHECKED(String, separator, 2);
   // elements_array is fast-mode JSarray of alternating positions
   // (increasing order) and strings.
   // array_length is length of original array (used to add separators);
   // separator is string to put between elements. Assumed to be non-empty.
 
@@ skipping 75 matching lines @@
                                        array_length,
                                        separator,
                                        Vector<uc16>(result_string->GetChars(),
                                                     string_length));
     return result_string;
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberOr) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromInt32(x | y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberAnd) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromInt32(x & y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberXor) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromInt32(x ^ y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberNot) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   return isolate->heap()->NumberFromInt32(~x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberShl) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromInt32(x << (y & 0x1f));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberShr) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(uint32_t, x, Uint32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromUint32(x >> (y & 0x1f));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberSar) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_NUMBER_CHECKED(int32_t, x, Int32, args[0]);
   CONVERT_NUMBER_CHECKED(int32_t, y, Int32, args[1]);
   return isolate->heap()->NumberFromInt32(ArithmeticShiftRight(x, y & 0x1f));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberEquals) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   if (std::isnan(x)) return Smi::FromInt(NOT_EQUAL);
   if (std::isnan(y)) return Smi::FromInt(NOT_EQUAL);
   if (x == y) return Smi::FromInt(EQUAL);
   Object* result;
   if ((fpclassify(x) == FP_ZERO) && (fpclassify(y) == FP_ZERO)) {
     result = Smi::FromInt(EQUAL);
   } else {
     result = Smi::FromInt(NOT_EQUAL);
   }
   return result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringEquals) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(String, x, 0);
   CONVERT_ARG_CHECKED(String, y, 1);
 
   bool not_equal = !x->Equals(y);
   // This is slightly convoluted because the value that signifies
   // equality is 0 and inequality is 1 so we have to negate the result
   // from String::Equals.
   ASSERT(not_equal == 0 || not_equal == 1);
   STATIC_CHECK(EQUAL == 0);
   STATIC_CHECK(NOT_EQUAL == 1);
   return Smi::FromInt(not_equal);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NumberCompare) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   if (std::isnan(x) || std::isnan(y)) return args[2];
   if (x == y) return Smi::FromInt(EQUAL);
   if (isless(x, y)) return Smi::FromInt(LESS);
   return Smi::FromInt(GREATER);
 }
 
 
 // Compare two Smis as if they were converted to strings and then
 // compared lexicographically.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SmiLexicographicCompare) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_SMI_ARG_CHECKED(x_value, 0);
   CONVERT_SMI_ARG_CHECKED(y_value, 1);
 
   // If the integers are equal so are the string representations.
   if (x_value == y_value) return Smi::FromInt(EQUAL);
 
   // If one of the integers is zero the normal integer order is the
   // same as the lexicographic order of the string representations.
   if (x_value == 0 || y_value == 0)
@@ skipping 83 matching lines @@
   ASSERT(y->IsFlat());
   Object* equal_prefix_result = Smi::FromInt(EQUAL);
   int prefix_length = x->length();
   if (y->length() < prefix_length) {
     prefix_length = y->length();
     equal_prefix_result = Smi::FromInt(GREATER);
   } else if (y->length() > prefix_length) {
     equal_prefix_result = Smi::FromInt(LESS);
   }
   int r;
-  AssertNoAllocation no_gc;
+  DisallowHeapAllocation no_gc;
   String::FlatContent x_content = x->GetFlatContent();
   String::FlatContent y_content = y->GetFlatContent();
   if (x_content.IsAscii()) {
     Vector<const uint8_t> x_chars = x_content.ToOneByteVector();
     if (y_content.IsAscii()) {
       Vector<const uint8_t> y_chars = y_content.ToOneByteVector();
       r = CompareChars(x_chars.start(), y_chars.start(), prefix_length);
     } else {
       Vector<const uc16> y_chars = y_content.ToUC16Vector();
       r = CompareChars(x_chars.start(), y_chars.start(), prefix_length);
@@ skipping 14 matching lines @@
   } else {
     result = (r < 0) ? Smi::FromInt(LESS) : Smi::FromInt(GREATER);
   }
   ASSERT(result ==
       StringCharacterStreamCompare(Isolate::Current()->runtime_state(), x, y));
   return result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringCompare) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(String, x, 0);
   CONVERT_ARG_CHECKED(String, y, 1);
 
   isolate->counters()->string_compare_runtime()->Increment();
 
   // A few fast case tests before we flatten.
   if (x == y) return Smi::FromInt(EQUAL);
   if (y->length() == 0) {
@@ skipping 14 matching lines @@
   { MaybeObject* maybe_obj = isolate->heap()->PrepareForCompare(y);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
 
   return (x->IsFlat() && y->IsFlat()) ? FlatStringCompare(x, y)
       : StringCharacterStreamCompare(isolate->runtime_state(), x, y);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_acos) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_acos()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::ACOS, x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_asin) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_asin()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::ASIN, x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_atan) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_atan()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::ATAN, x);
 }
 
 
 static const double kPiDividedBy4 = 0.78539816339744830962;
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_atan2) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   isolate->counters()->math_atan2()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   double result;
   if (std::isinf(x) && std::isinf(y)) {
     // Make sure that the result in case of two infinite arguments
     // is a multiple of Pi / 4. The sign of the result is determined
     // by the first argument (x) and the sign of the second argument
     // determines the multiplier: one or three.
     int multiplier = (x < 0) ? -1 : 1;
     if (y < 0) multiplier *= 3;
     result = multiplier * kPiDividedBy4;
   } else {
     result = atan2(x, y);
   }
   return isolate->heap()->AllocateHeapNumber(result);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_ceil) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_ceil()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->heap()->NumberFromDouble(ceiling(x));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_cos) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_cos()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::COS, x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_exp) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_exp()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   lazily_initialize_fast_exp();
   return isolate->heap()->NumberFromDouble(fast_exp(x));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_floor) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_floor()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->heap()->NumberFromDouble(floor(x));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_log) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_log()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::LOG, x);
 }
 
 // Slow version of Math.pow.  We check for fast paths for special cases.
 // Used if SSE2/VFP3 is not available.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_pow) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   isolate->counters()->math_pow()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
 
   // If the second argument is a smi, it is much faster to call the
   // custom powi() function than the generic pow().
   if (args[1]->IsSmi()) {
     int y = args.smi_at(1);
     return isolate->heap()->NumberFromDouble(power_double_int(x, y));
   }
 
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   double result = power_helper(x, y);
   if (std::isnan(result)) return isolate->heap()->nan_value();
   return isolate->heap()->AllocateHeapNumber(result);
 }
 
 // Fast version of Math.pow if we know that y is not an integer and y is not
 // -0.5 or 0.5.  Used as slow case from full codegen.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_pow_cfunction) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   isolate->counters()->math_pow()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   if (y == 0) {
     return Smi::FromInt(1);
   } else {
     double result = power_double_double(x, y);
     if (std::isnan(result)) return isolate->heap()->nan_value();
     return isolate->heap()->AllocateHeapNumber(result);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RoundNumber) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_round()->Increment();
 
   if (!args[0]->IsHeapNumber()) {
     // Must be smi. Return the argument unchanged for all the other types
     // to make fuzz-natives test happy.
     return args[0];
   }
 
   HeapNumber* number = reinterpret_cast<HeapNumber*>(args[0]);
@@ skipping 22 matching lines @@
   }
 
   if (sign && value >= -0.5) return isolate->heap()->minus_zero_value();
 
   // Do not call NumberFromDouble() to avoid extra checks.
   return isolate->heap()->AllocateHeapNumber(floor(value + 0.5));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_sin) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_sin()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::SIN, x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_sqrt) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_sqrt()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->heap()->AllocateHeapNumber(fast_sqrt(x));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_tan) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_tan()->Increment();
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   return isolate->transcendental_cache()->Get(TranscendentalCache::TAN, x);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateMakeDay) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_SMI_ARG_CHECKED(year, 0);
   CONVERT_SMI_ARG_CHECKED(month, 1);
 
   return Smi::FromInt(isolate->date_cache()->DaysFromYearMonth(year, month));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateSetValue) {
@@ skipping 122 matching lines @@
       for (int i = 0; i < argument_count; ++i) {
         elements->set(i, *(parameters - i - 1));
       }
     }
   }
   return *result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewStrictArgumentsFast) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
 
   JSFunction* callee = JSFunction::cast(args[0]);
   Object** parameters = reinterpret_cast<Object**>(args[1]);
   const int length = args.smi_at(2);
 
   Object* result;
   { MaybeObject* maybe_result =
         isolate->heap()->AllocateArgumentsObject(callee, length);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
   // Allocate the elements if needed.
   if (length > 0) {
     // Allocate the fixed array.
     Object* obj;
     { MaybeObject* maybe_obj = isolate->heap()->AllocateRawFixedArray(length);
       if (!maybe_obj->ToObject(&obj)) return maybe_obj;
     }
 
-    AssertNoAllocation no_gc;
+    DisallowHeapAllocation no_gc;
     FixedArray* array = reinterpret_cast<FixedArray*>(obj);
     array->set_map_no_write_barrier(isolate->heap()->fixed_array_map());
     array->set_length(length);
 
     WriteBarrierMode mode = array->GetWriteBarrierMode(no_gc);
     for (int i = 0; i < length; i++) {
       array->set(i, *--parameters, mode);
     }
     JSObject::cast(result)->set_elements(FixedArray::cast(obj));
   }
@@ skipping 402 matching lines @@
  private:
   JSFunction* function_;
   bool has_activations_;
 };
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NotifyStubFailure) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 0);
   Deoptimizer* deoptimizer = Deoptimizer::Grab(isolate);
-  ASSERT(isolate->heap()->IsAllocationAllowed());
+  ASSERT(AllowHeapAllocation::IsAllowed());
   delete deoptimizer;
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NotifyDeoptimized) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   RUNTIME_ASSERT(args[0]->IsSmi());
   Deoptimizer::BailoutType type =
       static_cast<Deoptimizer::BailoutType>(args.smi_at(0));
   Deoptimizer* deoptimizer = Deoptimizer::Grab(isolate);
-  ASSERT(isolate->heap()->IsAllocationAllowed());
+  ASSERT(AllowHeapAllocation::IsAllowed());
 
   ASSERT(deoptimizer->compiled_code_kind() == Code::OPTIMIZED_FUNCTION);
 
   // Make sure to materialize objects before causing any allocation.
   JavaScriptFrameIterator it(isolate);
   deoptimizer->MaterializeHeapObjects(&it);
   delete deoptimizer;
 
   JavaScriptFrame* frame = it.frame();
   RUNTIME_ASSERT(frame->function()->IsJSFunction());
@@ skipping 40 matching lines @@
   // Evict optimized code for this function from the cache so that it doesn't
   // get used for new closures.
   function->shared()->EvictFromOptimizedCodeMap(*optimized_code,
                                                 "notify deoptimized");
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NotifyOSR) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   Deoptimizer* deoptimizer = Deoptimizer::Grab(isolate);
   delete deoptimizer;
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DeoptimizeFunction) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
@@ skipping 12 matching lines @@
   Code* unoptimized = function->shared()->code();
   if (unoptimized->kind() == Code::FUNCTION) {
     unoptimized->ClearInlineCaches();
     unoptimized->ClearTypeFeedbackCells(isolate->heap());
   }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RunningInSimulator) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
 #if defined(USE_SIMULATOR)
   return isolate->heap()->true_value();
 #else
   return isolate->heap()->false_value();
 #endif
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_OptimizeFunctionOnNextCall) {
   HandleScope scope(isolate);
@@ skipping 178 matching lines @@
   } else {
     if (function->IsMarkedForLazyRecompilation()) {
       function->ReplaceCode(function->shared()->code());
     }
     return Smi::FromInt(-1);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CheckIsBootstrapping) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(isolate->bootstrapper()->IsActive());
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetRootNaN) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(isolate->bootstrapper()->IsActive());
   return isolate->heap()->nan_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Call) {
   HandleScope scope(isolate);
   ASSERT(args.length() >= 2);
   int argc = args.length() - 2;
   CONVERT_ARG_CHECKED(JSReceiver, fun, argc + 1);
@@ skipping 73 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetConstructorDelegate) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   RUNTIME_ASSERT(!args[0]->IsJSFunction());
   return *Execution::GetConstructorDelegate(args.at<Object>(0));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewGlobalContext) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_CHECKED(JSFunction, function, 0);
   CONVERT_ARG_CHECKED(ScopeInfo, scope_info, 1);
   Context* result;
   MaybeObject* maybe_result =
       isolate->heap()->AllocateGlobalContext(function, scope_info);
   if (!maybe_result->To(&result)) return maybe_result;
 
   ASSERT(function->context() == isolate->context());
   ASSERT(function->context()->global_object() == result->global_object());
   isolate->set_context(result);
   result->global_object()->set_global_context(result);
 
   return result;  // non-failure
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewFunctionContext) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, function, 0);
   int length = function->shared()->scope_info()->ContextLength();
   Context* result;
   MaybeObject* maybe_result =
       isolate->heap()->AllocateFunctionContext(length, function);
   if (!maybe_result->To(&result)) return maybe_result;
 
   isolate->set_context(result);
 
   return result;  // non-failure
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PushWithContext) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   JSObject* extension_object;
   if (args[0]->IsJSObject()) {
     extension_object = JSObject::cast(args[0]);
   } else {
     // Convert the object to a proper JavaScript object.
     MaybeObject* maybe_js_object = args[0]->ToObject();
     if (!maybe_js_object->To(&extension_object)) {
       if (Failure::cast(maybe_js_object)->IsInternalError()) {
         HandleScope scope(isolate);
@@ skipping 23 matching lines @@
       isolate->heap()->AllocateWithContext(function,
                                            isolate->context(),
                                            extension_object);
   if (!maybe_context->To(&context)) return maybe_context;
   isolate->set_context(context);
   return context;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PushCatchContext) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   String* name = String::cast(args[0]);
   Object* thrown_object = args[1];
   JSFunction* function;
   if (args[2]->IsSmi()) {
     // A smi sentinel indicates a context nested inside global code rather
     // than some function.  There is a canonical empty function that can be
     // gotten from the native context.
     function = isolate->context()->native_context()->closure();
   } else {
     function = JSFunction::cast(args[2]);
   }
   Context* context;
   MaybeObject* maybe_context =
       isolate->heap()->AllocateCatchContext(function,
                                             isolate->context(),
                                             name,
                                             thrown_object);
   if (!maybe_context->To(&context)) return maybe_context;
   isolate->set_context(context);
   return context;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PushBlockContext) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   ScopeInfo* scope_info = ScopeInfo::cast(args[0]);
   JSFunction* function;
   if (args[1]->IsSmi()) {
     // A smi sentinel indicates a context nested inside global code rather
     // than some function.  There is a canonical empty function that can be
     // gotten from the native context.
     function = isolate->context()->native_context()->closure();
   } else {
     function = JSFunction::cast(args[1]);
   }
   Context* context;
   MaybeObject* maybe_context =
       isolate->heap()->AllocateBlockContext(function,
                                             isolate->context(),
                                             scope_info);
   if (!maybe_context->To(&context)) return maybe_context;
   isolate->set_context(context);
   return context;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsJSModule) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   return isolate->heap()->ToBoolean(obj->IsJSModule());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PushModuleContext) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_SMI_ARG_CHECKED(index, 0);
 
   if (!args[1]->IsScopeInfo()) {
     // Module already initialized. Find hosting context and retrieve context.
     Context* host = Context::cast(isolate->context())->global_context();
     Context* context = Context::cast(host->get(index));
     ASSERT(context->previous() == isolate->context());
     isolate->set_context(context);
     return context;
@@ skipping 363 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ReThrow) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   return isolate->ReThrow(args[0]);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PromoteScheduledException) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT_EQ(0, args.length());
   return isolate->PromoteScheduledException();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ThrowReferenceError) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   Handle<Object> name(args[0], isolate);
   Handle<Object> reference_error =
     isolate->factory()->NewReferenceError("not_defined",
                                           HandleVector(&name, 1));
   return isolate->Throw(*reference_error);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ThrowNotDateError) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 0);
   return isolate->Throw(*isolate->factory()->NewTypeError(
       "not_date_object", HandleVector<Object>(NULL, 0)));
 }
 
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StackGuard) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
 
   // First check if this is a real stack overflow.
   if (isolate->stack_guard()->IsStackOverflow()) {
-    NoHandleAllocation na(isolate);
+    SealHandleScope shs(isolate);
     return isolate->StackOverflow();
   }
 
   return Execution::HandleStackGuardInterrupt(isolate);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Interrupt) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   return Execution::HandleStackGuardInterrupt(isolate);
 }
 
 
 static int StackSize(Isolate* isolate) {
   int n = 0;
   for (JavaScriptFrameIterator it(isolate); !it.done(); it.Advance()) n++;
   return n;
 }
@@ skipping 15 matching lines @@
   } else {
     // function result
     PrintF("} -> ");
     result->ShortPrint();
     PrintF("\n");
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_TraceEnter) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   PrintTransition(isolate, NULL);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_TraceExit) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   PrintTransition(isolate, args[0]);
   return args[0];  // return TOS
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPrint) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
 #ifdef DEBUG
   if (args[0]->IsString()) {
     // If we have a string, assume it's a code "marker"
     // and print some interesting cpu debugging info.
     JavaScriptFrameIterator it(isolate);
     JavaScriptFrame* frame = it.frame();
     PrintF("fp = %p, sp = %p, caller_sp = %p: ",
            frame->fp(), frame->sp(), frame->caller_sp());
@@ skipping 10 matching lines @@
   args[0]->ShortPrint();
 #endif
   PrintF("\n");
   Flush();
 
   return args[0];  // return TOS
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugTrace) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   isolate->PrintStack(stdout);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateCurrentTime) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
 
   // According to ECMA-262, section 15.9.1, page 117, the precision of
   // the number in a Date object representing a particular instant in
   // time is milliseconds. Therefore, we floor the result of getting
   // the OS time.
   double millis = floor(OS::TimeCurrentMillis());
   return isolate->heap()->NumberFromDouble(millis);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateParseString) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_HANDLE_CHECKED(String, str, 0);
   FlattenString(str);
 
   CONVERT_ARG_HANDLE_CHECKED(JSArray, output, 1);
 
   MaybeObject* maybe_result_array =
       output->EnsureCanContainHeapObjectElements();
   if (maybe_result_array->IsFailure()) return maybe_result_array;
   RUNTIME_ASSERT(output->HasFastObjectElements());
 
-  AssertNoAllocation no_allocation;
+  DisallowHeapAllocation no_gc;
 
   FixedArray* output_array = FixedArray::cast(output->elements());
   RUNTIME_ASSERT(output_array->length() >= DateParser::OUTPUT_SIZE);
   bool result;
   String::FlatContent str_content = str->GetFlatContent();
   if (str_content.IsAscii()) {
     result = DateParser::Parse(str_content.ToOneByteVector(),
                                output_array,
                                isolate->unicode_cache());
   } else {
     ASSERT(str_content.IsTwoByte());
     result = DateParser::Parse(str_content.ToUC16Vector(),
                                output_array,
                                isolate->unicode_cache());
   }
 
   if (result) {
     return *output;
   } else {
     return isolate->heap()->null_value();
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateLocalTimezone) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   int64_t time = isolate->date_cache()->EquivalentTime(static_cast<int64_t>(x));
   const char* zone = OS::LocalTimezone(static_cast<double>(time));
   return isolate->heap()->AllocateStringFromUtf8(CStrVector(zone));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DateToUTC) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   int64_t time = isolate->date_cache()->ToUTC(static_cast<int64_t>(x));
 
   return isolate->heap()->NumberFromDouble(static_cast<double>(time));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GlobalReceiver) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* global = args[0];
   if (!global->IsJSGlobalObject()) return isolate->heap()->null_value();
   return JSGlobalObject::cast(global)->global_receiver();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ParseJson) {
   HandleScope scope(isolate);
   ASSERT_EQ(1, args.length());
@@ skipping 128 matching lines @@
                            args.smi_at(4));
 }
 
 
 static MaybeObject* Allocate(Isolate* isolate,
                              int size,
                              AllocationSpace space) {
   // Allocate a block of memory in the given space (filled with a filler).
   // Use as fallback for allocation in generated code when the space
   // is full.
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   RUNTIME_ASSERT(IsAligned(size, kPointerSize));
   RUNTIME_ASSERT(size > 0);
   Heap* heap = isolate->heap();
   RUNTIME_ASSERT(size <= heap->MaxRegularSpaceAllocationSize());
   Object* allocation;
   { MaybeObject* maybe_allocation;
     if (space == NEW_SPACE) {
       maybe_allocation = heap->new_space()->AllocateRaw(size);
     } else {
       ASSERT(space == OLD_POINTER_SPACE || space == OLD_DATA_SPACE);
       maybe_allocation = heap->paged_space(space)->AllocateRaw(size);
     }
     if (maybe_allocation->ToObject(&allocation)) {
       heap->CreateFillerObjectAt(HeapObject::cast(allocation)->address(), size);
     }
     return maybe_allocation;
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_AllocateInNewSpace) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Smi, size_smi, 0);
   return Allocate(isolate, size_smi->value(), NEW_SPACE);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_AllocateInOldPointerSpace) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Smi, size_smi, 0);
   return Allocate(isolate, size_smi->value(), OLD_POINTER_SPACE);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_AllocateInOldDataSpace) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Smi, size_smi, 0);
   return Allocate(isolate, size_smi->value(), OLD_DATA_SPACE);
 }
 
 
 // Push an object unto an array of objects if it is not already in the
 // array.  Returns true if the element was pushed on the stack and
 // false otherwise.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PushIfAbsent) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSArray, array, 0);
   CONVERT_ARG_CHECKED(JSReceiver, element, 1);
   RUNTIME_ASSERT(array->HasFastSmiOrObjectElements());
   int length = Smi::cast(array->length())->value();
   FixedArray* elements = FixedArray::cast(array->elements());
   for (int i = 0; i < length; i++) {
     if (elements->get(i) == element) return isolate->heap()->false_value();
   }
   Object* obj;
@@ skipping 696 matching lines @@
         *isolate->factory()->NewRangeError("invalid_array_length",
                                            HandleVector<Object>(NULL, 0)));
   }
   return *visitor.ToArray();
 }
 
 
 // This will not allocate (flatten the string), but it may run
 // very slowly for very deeply nested ConsStrings.  For debugging use only.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GlobalPrint) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(String, string, 0);
   ConsStringIteratorOp op;
   StringCharacterStream stream(string, &op);
   while (stream.HasMore()) {
     uint16_t character = stream.GetNext();
     PrintF("%c", character);
   }
   return string;
 }
 
 // Moves all own elements of an object, that are below a limit, to positions
 // starting at zero. All undefined values are placed after non-undefined values,
 // and are followed by non-existing element. Does not change the length
 // property.
 // Returns the number of non-undefined elements collected.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RemoveArrayHoles) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSObject, object, 0);
   CONVERT_NUMBER_CHECKED(uint32_t, limit, Uint32, args[1]);
   return object->PrepareElementsForSort(limit);
 }
 
 
 // Move contents of argument 0 (an array) to argument 1 (an array)
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MoveArrayContents) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSArray, from, 0);
   CONVERT_ARG_CHECKED(JSArray, to, 1);
   from->ValidateElements();
   to->ValidateElements();
   FixedArrayBase* new_elements = from->elements();
   ElementsKind from_kind = from->GetElementsKind();
   MaybeObject* maybe_new_map;
   maybe_new_map = to->GetElementsTransitionMap(isolate, from_kind);
   Object* new_map;
   if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
   to->set_map_and_elements(Map::cast(new_map), new_elements);
   to->set_length(from->length());
   Object* obj;
   { MaybeObject* maybe_obj = from->ResetElements();
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   from->set_length(Smi::FromInt(0));
   to->ValidateElements();
   return to;
 }
 
 
 // How many elements does this object/array have?
 RUNTIME_FUNCTION(MaybeObject*, Runtime_EstimateNumberOfElements) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, object, 0);
   HeapObject* elements = object->elements();
   if (elements->IsDictionary()) {
     int result = SeededNumberDictionary::cast(elements)->NumberOfElements();
     return Smi::FromInt(result);
   } else if (object->IsJSArray()) {
     return JSArray::cast(object)->length();
   } else {
     return Smi::FromInt(FixedArray::cast(elements)->length());
@@ skipping 38 matching lines @@
   } else {
     ASSERT(array->HasFastSmiOrObjectElements() ||
            array->HasFastDoubleElements());
     uint32_t actual_length = static_cast<uint32_t>(array->elements()->length());
     return *isolate->factory()->NewNumberFromUint(Min(actual_length, length));
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LookupAccessor) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
   CONVERT_ARG_CHECKED(JSReceiver, receiver, 0);
   CONVERT_ARG_CHECKED(Name, name, 1);
   CONVERT_SMI_ARG_CHECKED(flag, 2);
   AccessorComponent component = flag == 0 ? ACCESSOR_GETTER : ACCESSOR_SETTER;
   if (!receiver->IsJSObject()) return isolate->heap()->undefined_value();
   return JSObject::cast(receiver)->LookupAccessor(name, component);
 }
 
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugBreak) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   return Execution::DebugBreakHelper();
 }
 
 
 // Helper functions for wrapping and unwrapping stack frame ids.
 static Smi* WrapFrameId(StackFrame::Id id) {
   ASSERT(IsAligned(OffsetFrom(id), static_cast<intptr_t>(4)));
   return Smi::FromInt(id >> 2);
 }
 
 
 static StackFrame::Id UnwrapFrameId(int wrapped) {
   return static_cast<StackFrame::Id>(wrapped << 2);
 }
 
 
 // Adds a JavaScript function as a debug event listener.
 // args[0]: debug event listener function to set or null or undefined for
 //          clearing the event listener function
 // args[1]: object supplied during callback
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetDebugEventListener) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   RUNTIME_ASSERT(args[0]->IsJSFunction() ||
                  args[0]->IsUndefined() ||
                  args[0]->IsNull());
   Handle<Object> callback = args.at<Object>(0);
   Handle<Object> data = args.at<Object>(1);
   isolate->debugger()->SetEventListener(callback, data);
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Break) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   isolate->stack_guard()->DebugBreak();
   return isolate->heap()->undefined_value();
 }
 
 
 static MaybeObject* DebugLookupResultValue(Heap* heap,
                                            Object* receiver,
                                            Name* name,
                                            LookupResult* result,
@@ skipping 177 matching lines @@
   if (result.IsFound()) {
     return DebugLookupResultValue(isolate->heap(), *obj, *name, &result, NULL);
   }
   return isolate->heap()->undefined_value();
 }
 
 
 // Return the property type calculated from the property details.
 // args[0]: smi with property details.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPropertyTypeFromDetails) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_PROPERTY_DETAILS_CHECKED(details, 0);
   return Smi::FromInt(static_cast<int>(details.type()));
 }
 
 
 // Return the property attribute calculated from the property details.
 // args[0]: smi with property details.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPropertyAttributesFromDetails) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_PROPERTY_DETAILS_CHECKED(details, 0);
   return Smi::FromInt(static_cast<int>(details.attributes()));
 }
 
 
 // Return the property insertion index calculated from the property details.
 // args[0]: smi with property details.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPropertyIndexFromDetails) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_PROPERTY_DETAILS_CHECKED(details, 0);
   // TODO(verwaest): Depends on the type of details.
   return Smi::FromInt(details.dictionary_index());
 }
 
 
 // Return property value from named interceptor.
 // args[0]: object
 // args[1]: property name
@@ skipping 17 matching lines @@
   ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, obj, 0);
   RUNTIME_ASSERT(obj->HasIndexedInterceptor());
   CONVERT_NUMBER_CHECKED(uint32_t, index, Uint32, args[1]);
 
   return obj->GetElementWithInterceptor(*obj, index);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CheckExecutionState) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() >= 1);
   CONVERT_NUMBER_CHECKED(int, break_id, Int32, args[0]);
   // Check that the break id is valid.
   if (isolate->debug()->break_id() == 0 ||
       break_id != isolate->debug()->break_id()) {
     return isolate->Throw(
         isolate->heap()->illegal_execution_state_string());
   }
 
   return isolate->heap()->true_value();
@@ skipping 1880 matching lines @@
 }
 
 
 // Helper function used by Runtime_DebugReferencedBy below.
 static int DebugReferencedBy(HeapIterator* iterator,
                              JSObject* target,
                              Object* instance_filter, int max_references,
                              FixedArray* instances, int instances_size,
                              JSFunction* arguments_function) {
   Isolate* isolate = target->GetIsolate();
-  NoHandleAllocation ha(isolate);
-  AssertNoAllocation no_alloc;
+  SealHandleScope shs(isolate);
+  DisallowHeapAllocation no_allocation;
 
   // Iterate the heap.
   int count = 0;
   JSObject* last = NULL;
   HeapObject* heap_obj = NULL;
   while (((heap_obj = iterator->next()) != NULL) &&
          (max_references == 0 || count < max_references)) {
     // Only look at all JSObjects.
     if (heap_obj->IsJSObject()) {
       // Skip context extension objects and argument arrays as these are
@@ skipping 47 matching lines @@
   // Return the number of referencing objects found.
   return count;
 }
 
 
 // Scan the heap for objects with direct references to an object
 // args[0]: the object to find references to
 // args[1]: constructor function for instances to exclude (Mirror)
 // args[2]: the the maximum number of objects to return
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugReferencedBy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 3);
 
   // First perform a full GC in order to avoid references from dead objects.
   isolate->heap()->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                                      "%DebugReferencedBy");
   // The heap iterator reserves the right to do a GC to make the heap iterable.
   // Due to the GC above we know it won't need to do that, but it seems cleaner
   // to get the heap iterator constructed before we start having unprotected
   // Object* locals that are not protected by handles.
 
@@ skipping 43 matching lines @@
   return JSArray::cast(result)->SetContent(instances);
 }
 
 
 // Helper function used by Runtime_DebugConstructedBy below.
 static int DebugConstructedBy(HeapIterator* iterator,
                               JSFunction* constructor,
                               int max_references,
                               FixedArray* instances,
                               int instances_size) {
-  AssertNoAllocation no_alloc;
+  DisallowHeapAllocation no_allocation;
 
   // Iterate the heap.
   int count = 0;
   HeapObject* heap_obj = NULL;
   while (((heap_obj = iterator->next()) != NULL) &&
          (max_references == 0 || count < max_references)) {
     // Only look at all JSObjects.
     if (heap_obj->IsJSObject()) {
       JSObject* obj = JSObject::cast(heap_obj);
       if (obj->map()->constructor() == constructor) {
         // Valid reference found add to instance array if supplied an update
         // count.
         if (instances != NULL && count < instances_size) {
           instances->set(count, obj);
         }
         count++;
       }
     }
   }
 
   // Return the number of referencing objects found.
   return count;
 }
 
 
 // Scan the heap for objects constructed by a specific function.
 // args[0]: the constructor to find instances of
 // args[1]: the the maximum number of objects to return
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugConstructedBy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
 
   // First perform a full GC in order to avoid dead objects.
   Heap* heap = isolate->heap();
   heap->CollectAllGarbage(Heap::kMakeHeapIterableMask, "%DebugConstructedBy");
 
   // Check parameters.
   CONVERT_ARG_CHECKED(JSFunction, constructor, 0);
   CONVERT_NUMBER_CHECKED(int32_t, max_references, Int32, args[1]);
   RUNTIME_ASSERT(max_references >= 0);
@@ skipping 29 matching lines @@
       isolate->context()->native_context()->array_function());
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
   return JSArray::cast(result)->SetContent(instances);
 }
 
 
 // Find the effective prototype object as returned by __proto__.
 // args[0]: the object to find the prototype for.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugGetPrototype) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   return GetPrototypeSkipHiddenPrototypes(isolate, obj);
 }
 
 
 // Patches script source (should be called upon BeforeCompile event).
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugSetScriptSource) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
   CONVERT_ARG_HANDLE_CHECKED(JSValue, script_wrapper, 0);
   CONVERT_ARG_HANDLE_CHECKED(String, source, 1);
 
   RUNTIME_ASSERT(script_wrapper->value()->IsScript());
   Handle<Script> script(Script::cast(script_wrapper->value()));
 
   int compilation_state = Smi::cast(script->compilation_state())->value();
   RUNTIME_ASSERT(compilation_state == Script::COMPILATION_STATE_INITIAL);
   script->set_source(*source);
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SystemBreak) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   CPU::DebugBreak();
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugDisassembleFunction) {
   HandleScope scope(isolate);
 #ifdef DEBUG
   ASSERT(args.length() == 1);
@@ skipping 17 matching lines @@
   if (!JSFunction::EnsureCompiled(func, KEEP_EXCEPTION)) {
     return Failure::Exception();
   }
   func->shared()->construct_stub()->PrintLn();
 #endif  // DEBUG
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionGetInferredName) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return f->shared()->inferred_name();
 }
 
 
 static int FindSharedFunctionInfosForScript(HeapIterator* iterator,
                                             Script* script,
                                             FixedArray* buffer) {
-  AssertNoAllocation no_allocations;
+  DisallowHeapAllocation no_allocation;
   int counter = 0;
   int buffer_size = buffer->length();
   for (HeapObject* obj = iterator->next();
        obj != NULL;
        obj = iterator->next()) {
     ASSERT(obj != NULL);
     if (!obj->IsSharedFunctionInfo()) {
       continue;
     }
     SharedFunctionInfo* shared = SharedFunctionInfo::cast(obj);
@@ skipping 22 matching lines @@
   Handle<Script> script = Handle<Script>(Script::cast(script_value->value()));
 
   const int kBufferSize = 32;
 
   Handle<FixedArray> array;
   array = isolate->factory()->NewFixedArray(kBufferSize);
   int number;
   Heap* heap = isolate->heap();
   {
     heap->EnsureHeapIsIterable();
-    AssertNoAllocation no_allocations;
+    DisallowHeapAllocation no_allocation;
     HeapIterator heap_iterator(heap);
     Script* scr = *script;
     FixedArray* arr = *array;
     number = FindSharedFunctionInfosForScript(&heap_iterator, scr, arr);
   }
   if (number > kBufferSize) {
     array = isolate->factory()->NewFixedArray(number);
     heap->EnsureHeapIsIterable();
-    AssertNoAllocation no_allocations;
+    DisallowHeapAllocation no_allocation;
     HeapIterator heap_iterator(heap);
     Script* scr = *script;
     FixedArray* arr = *array;
     FindSharedFunctionInfosForScript(&heap_iterator, scr, arr);
   }
 
   Handle<JSArray> result = isolate->factory()->NewJSArrayWithElements(array);
   result->set_length(Smi::FromInt(number));
 
   LiveEdit::WrapSharedFunctionInfos(result);
@@ skipping 264 matching lines @@
   if (!pending_exception) {
     return *result;
   } else {
     return Failure::Exception();
   }
 }
 
 
 // Sets a v8 flag.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetFlags) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   CONVERT_ARG_CHECKED(String, arg, 0);
   SmartArrayPointer<char> flags =
       arg->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
   FlagList::SetFlagsFromString(*flags, StrLength(*flags));
   return isolate->heap()->undefined_value();
 }
 
 
 // Performs a GC.
 // Presently, it only does a full GC.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CollectGarbage) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags, "%CollectGarbage");
   return isolate->heap()->undefined_value();
 }
 
 
 // Gets the current heap usage.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetHeapUsage) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   int usage = static_cast<int>(isolate->heap()->SizeOfObjects());
   if (!Smi::IsValid(usage)) {
     return *isolate->factory()->NewNumberFromInt(usage);
   }
   return Smi::FromInt(usage);
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ProfilerResume) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   v8::V8::ResumeProfiler();
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ProfilerPause) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   v8::V8::PauseProfiler();
   return isolate->heap()->undefined_value();
 }
 
 
 // Finds the script object from the script data. NOTE: This operation uses
 // heap traversal to find the function generated for the source position
 // for the requested break point. For lazily compiled functions several heap
 // traversals might be required rendering this operation as a rather slow
 // operation. However for setting break points which is normally done through
 // some kind of user interaction the performance is not crucial.
 static Handle<Object> Runtime_GetScriptFromScriptName(
     Handle<String> script_name) {
   // Scan the heap for Script objects to find the script with the requested
   // script data.
   Handle<Script> script;
   Heap* heap = script_name->GetHeap();
   heap->EnsureHeapIsIterable();
-  AssertNoAllocation no_allocation_during_heap_iteration;
+  DisallowHeapAllocation no_allocation_during_heap_iteration;
   HeapIterator iterator(heap);
   HeapObject* obj = NULL;
   while (script.is_null() && ((obj = iterator.next()) != NULL)) {
     // If a script is found check if it has the script data requested.
     if (obj->IsScript()) {
       if (Script::cast(obj)->name()->IsString()) {
         if (String::cast(Script::cast(obj)->name())->Equals(*script_name)) {
           script = Handle<Script>(Script::cast(obj));
         }
       }
@@ skipping 80 matching lines @@
   } else {
     RUNTIME_ASSERT(value->IsString());
     JSObject::SetHiddenProperty(error_object, key, value);
   }
   return *error_object;
 }
 
 
 // Returns V8 version as a string.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetV8Version) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT_EQ(args.length(), 0);
 
   const char* version_string = v8::V8::GetVersion();
 
   return isolate->heap()->AllocateStringFromOneByte(CStrVector(version_string),
                                                   NOT_TENURED);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Abort) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   OS::PrintError("abort: %s\n",
                  reinterpret_cast<char*>(args[0]) + args.smi_at(1));
   isolate->PrintStack(stderr);
   OS::Abort();
   UNREACHABLE();
   return NULL;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FlattenString) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(String, str, 0);
   FlattenString(str);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFromCache) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   // This is only called from codegen, so checks might be more lax.
   CONVERT_ARG_CHECKED(JSFunctionResultCache, cache, 0);
   Object* key = args[1];
 
   int finger_index = cache->finger_index();
   Object* o = cache->get(finger_index);
   if (o == key) {
     // The fastest case: hit the same place again.
     return cache->get(finger_index + 1);
   }
@@ skipping 77 matching lines @@
   if (FLAG_verify_heap) {
     cache_handle->JSFunctionResultCacheVerify();
   }
 #endif
 
   return *value;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MessageGetStartPosition) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   CONVERT_ARG_CHECKED(JSMessageObject, message, 0);
   return Smi::FromInt(message->start_position());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_MessageGetScript) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   CONVERT_ARG_CHECKED(JSMessageObject, message, 0);
   return message->script();
 }
 
 
 #ifdef DEBUG
 // ListNatives is ONLY used by the fuzz-natives.js in debug mode
 // Exclude the code in release mode.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ListNatives) {
   HandleScope scope(isolate);
@@ skipping 33 matching lines @@
   INLINE_RUNTIME_FUNCTION_LIST(ADD_ENTRY)
 #undef ADD_ENTRY
   ASSERT_EQ(index, entry_count);
   Handle<JSArray> result = factory->NewJSArrayWithElements(elements);
   return *result;
 }
 #endif
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Log) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(String, format, 0);
   CONVERT_ARG_CHECKED(JSArray, elms, 1);
-  AssertNoAllocation no_gc;
+  DisallowHeapAllocation no_gc;
   String::FlatContent format_content = format->GetFlatContent();
   RUNTIME_ASSERT(format_content.IsAscii());
   Vector<const uint8_t> chars = format_content.ToOneByteVector();
   isolate->logger()->LogRuntime(Vector<const char>::cast(chars), elms);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IS_VAR) {
   UNREACHABLE();  // implemented as macro in the parser
@@ skipping 24 matching lines @@
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalUnsignedIntElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalFloatElements)
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(ExternalDoubleElements)
 // Properties test sitting with elements tests - not fooling anyone.
 ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION(FastProperties)
 
 #undef ELEMENTS_KIND_CHECK_RUNTIME_FUNCTION
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_HaveSameMap) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSObject, obj1, 0);
   CONVERT_ARG_CHECKED(JSObject, obj2, 1);
   return isolate->heap()->ToBoolean(obj1->map() == obj2->map());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsObserved) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
 
   if (!args[0]->IsJSReceiver()) return isolate->heap()->false_value();
   JSReceiver* obj = JSReceiver::cast(args[0]);
   if (obj->IsJSGlobalProxy()) {
     Object* proto = obj->GetPrototype();
     if (proto->IsNull()) return isolate->heap()->false_value();
     ASSERT(proto->IsJSGlobalObject());
     obj = JSReceiver::cast(proto);
   }
   return isolate->heap()->ToBoolean(obj->map()->is_observed());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetIsObserved) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSReceiver, obj, 0);
   CONVERT_BOOLEAN_ARG_CHECKED(is_observed, 1);
   if (obj->IsJSGlobalProxy()) {
     Object* proto = obj->GetPrototype();
     if (proto->IsNull()) return isolate->heap()->undefined_value();
     ASSERT(proto->IsJSGlobalObject());
     obj = JSReceiver::cast(proto);
   }
   ASSERT(!(obj->map()->is_observed() && obj->IsJSObject() &&
@@ skipping 10 matching lines @@
     Map* map;
     if (!maybe->To(&map)) return maybe;
     map->set_is_observed(is_observed);
     obj->set_map(map);
   }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetObserverDeliveryPending) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   isolate->set_observer_delivery_pending(true);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetObservationState) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   return isolate->heap()->observation_state();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ObservationWeakMapCreate) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 0);
   // TODO(adamk): Currently this runtime function is only called three times per
   // isolate. If it's called more often, the map should be moved into the
   // strong root list.
   Handle<Map> map =
       isolate->factory()->NewMap(JS_WEAK_MAP_TYPE, JSWeakMap::kSize);
   Handle<JSWeakMap> weakmap =
       Handle<JSWeakMap>::cast(isolate->factory()->NewJSObjectFromMap(map));
   return WeakMapInitialize(isolate, weakmap);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_UnwrapGlobalProxy) {
-  NoHandleAllocation ha(isolate);
+  SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   Object* object = args[0];
   if (object->IsJSGlobalProxy()) {
     object = object->GetPrototype(isolate);
     if (object->IsNull()) return isolate->heap()->undefined_value();
   }
   return object;
 }
 
 
@@ skipping 76 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal