Install iterator meta objects via utils object.

src/bootstrapper.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/code-stubs.h"
@@ skipping 146 matching lines @@
   void CreateRoots();
   // Creates the empty function.  Used for creating a context from scratch.
   Handle<JSFunction> CreateEmptyFunction(Isolate* isolate);
   // Creates the ThrowTypeError function. ECMA 5th Ed. 13.2.3
   Handle<JSFunction> GetRestrictedFunctionPropertiesThrower();
   Handle<JSFunction> GetStrictArgumentsPoisonFunction();
   Handle<JSFunction> GetThrowTypeErrorIntrinsic(Builtins::Name builtin_name);
 
   void CreateStrictModeFunctionMaps(Handle<JSFunction> empty);
   void CreateStrongModeFunctionMaps(Handle<JSFunction> empty);
+  void CreateIteratorMaps();
 
   // Make the "arguments" and "caller" properties throw a TypeError on access.
   void AddRestrictedFunctionProperties(Handle<Map> map);
 
   // Creates the global objects using the global proxy and the template passed
   // in through the API.  We call this regardless of whether we are building a
   // context from scratch or using a deserialized one from the partial snapshot
   // but in the latter case we don't use the objects it produces directly, as
   // we have to used the deserialized ones that are linked together with the
   // rest of the context snapshot.
@@ skipping 15 matching lines @@
   // global proxy.
   void InstallGlobalThisBinding();
   void HookUpGlobalThisBinding(Handle<FixedArray> outdated_contexts);
   // New context initialization.  Used for creating a context from scratch.
   void InitializeGlobal(Handle<GlobalObject> global_object,
                         Handle<JSFunction> empty_function,
                         ContextType context_type);
   void InitializeExperimentalGlobal();
   // Typed arrays are not serializable and have to initialized afterwards.
   void InitializeBuiltinTypedArrays();
+  // Depending on the situation, expose and/or get rid of the utils object.
+  void ConfigureUtilsObject(ContextType context_type);
 
 #define DECLARE_FEATURE_INITIALIZATION(id, descr) \
   void InitializeGlobal_##id();
 
   HARMONY_INPROGRESS(DECLARE_FEATURE_INITIALIZATION)
   HARMONY_STAGED(DECLARE_FEATURE_INITIALIZATION)
   HARMONY_SHIPPING(DECLARE_FEATURE_INITIALIZATION)
 #undef DECLARE_FEATURE_INITIALIZATION
 
   Handle<JSFunction> InstallInternalArray(Handle<JSObject> target,
@@ skipping 574 matching lines @@
 void Genesis::CreateStrongModeFunctionMaps(Handle<JSFunction> empty) {
   // Allocate map for strong mode instances, which never have prototypes.
   Handle<Map> strong_function_map = CreateStrongFunctionMap(empty, false);
   native_context()->set_strong_function_map(*strong_function_map);
   // Constructors do, though.
   Handle<Map> strong_constructor_map = CreateStrongFunctionMap(empty, true);
   native_context()->set_strong_constructor_map(*strong_constructor_map);
 }
 
 
+void Genesis::CreateIteratorMaps() {
+  // Create iterator-related meta-objects.
+  Handle<JSObject> iterator_prototype =
+      factory()->NewJSObject(isolate()->object_function(), TENURED);
+  Handle<JSObject> generator_object_prototype =
+      factory()->NewJSObject(isolate()->object_function(), TENURED);
+  Handle<JSObject> generator_function_prototype =
+      factory()->NewJSObject(isolate()->object_function(), TENURED);
+  SetObjectPrototype(generator_object_prototype, iterator_prototype);
+
+  JSObject::AddProperty(generator_function_prototype,
+                        factory()->InternalizeUtf8String("prototype"),
+                        generator_object_prototype,
+                        static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY));
+
+  // Create maps for generator functions and their prototypes.  Store those
+  // maps in the native context. The "prototype" property descriptor is
+  // writable, non-enumerable, and non-configurable (as per ES6 draft
+  // 04-14-15, section 25.2.4.3).
+  Handle<Map> strict_function_map(strict_function_map_writable_prototype_);
+  // Generator functions do not have "caller" or "arguments" accessors.
+  Handle<Map> sloppy_generator_function_map =
+      Map::Copy(strict_function_map, "SloppyGeneratorFunction");
+  Map::SetPrototype(sloppy_generator_function_map,
+                    generator_function_prototype);
+  native_context()->set_sloppy_generator_function_map(
+      *sloppy_generator_function_map);
+
+  Handle<Map> strict_generator_function_map =
+      Map::Copy(strict_function_map, "StrictGeneratorFunction");
+  Map::SetPrototype(strict_generator_function_map,
+                    generator_function_prototype);
+  native_context()->set_strict_generator_function_map(
+      *strict_generator_function_map);
+
+  Handle<Map> strong_function_map(native_context()->strong_function_map());
+  Handle<Map> strong_generator_function_map =
+      Map::Copy(strong_function_map, "StrongGeneratorFunction");
+  Map::SetPrototype(strong_generator_function_map,
+                    generator_function_prototype);
+  native_context()->set_strong_generator_function_map(
+      *strong_generator_function_map);
+
+  Handle<JSFunction> object_function(native_context()->object_function());
+  Handle<Map> generator_object_prototype_map = Map::Create(isolate(), 0);
+  Map::SetPrototype(generator_object_prototype_map, generator_object_prototype);
+  native_context()->set_generator_object_prototype_map(
+      *generator_object_prototype_map);
+}
+
+
 static void ReplaceAccessors(Handle<Map> map,
                              Handle<String> name,
                              PropertyAttributes attributes,
                              Handle<AccessorPair> accessor_pair) {
   DescriptorArray* descriptors = map->instance_descriptors();
   int idx = descriptors->SearchWithCache(*name, *map);
   AccessorConstantDescriptor descriptor(name, accessor_pair, attributes);
   descriptors->Replace(idx, &descriptor);
 }
 
@@ skipping 981 matching lines @@
   {  // Initialize a result array for rempio2 calculation
     const size_t num_elements = 2;
     double* data =
         SetBuiltinTypedArray<double>(isolate(), builtins, kExternalFloat64Array,
                                      NULL, num_elements, "rempio2result");
     for (size_t i = 0; i < num_elements; i++) data[i] = 0;
   }
 }
 
 
+void Genesis::ConfigureUtilsObject(ContextType context_type) {
+  switch (context_type) {
+    // We still need the utils object to find debug functions.
+    case DEBUG_CONTEXT:
+      return;
+    // Expose the natives in global if a valid name for it is specified.
+    case FULL_CONTEXT: {
+      // We still need the utils object after deserialization.
+      if (isolate()->serializer_enabled()) return;
+      if (FLAG_expose_natives_as == NULL) break;
+      if (strlen(FLAG_expose_natives_as) == 0) break;
+      HandleScope scope(isolate());
+      Handle<String> natives_key =
+          factory()->InternalizeUtf8String(FLAG_expose_natives_as);
+      uint32_t dummy_index;
+      if (natives_key->AsArrayIndex(&dummy_index)) break;
+      Handle<Object> utils = isolate()->natives_utils_object();
+      Handle<JSObject> global = isolate()->global_object();
+      JSObject::AddProperty(global, natives_key, utils, DONT_ENUM);
+      break;
+    }
+    case THIN_CONTEXT:
+      break;
+  }
+
+  // The utils object can be removed for cases that reach this point.
+  native_context()->set_natives_utils_object(heap()->undefined_value());
+}
+
+
 void Bootstrapper::ExportFromRuntime(Isolate* isolate,
                                      Handle<JSObject> container) {
   HandleScope scope(isolate);
 #define EXPORT_PRIVATE_SYMBOL(NAME)                                         \
   Handle<String> NAME##_name =                                              \
       isolate->factory()->NewStringFromAsciiChecked(#NAME);                 \
   JSObject::AddProperty(container, NAME##_name, isolate->factory()->NAME(), \
                         NONE);
   PRIVATE_SYMBOL_LIST(EXPORT_PRIVATE_SYMBOL)
 #undef EXPORT_PRIVATE_SYMBOL
@@ skipping 23 matching lines @@
     Handle<JSFunction> construct = InstallFunction(
         container, "reflect_construct", JS_OBJECT_TYPE, JSObject::kHeaderSize,
         MaybeHandle<JSObject>(), Builtins::kReflectConstruct);
     construct->shared()->set_internal_formal_parameter_count(3);
     construct->shared()->set_length(2);
     Handle<TypeFeedbackVector> feedback_vector =
         TypeFeedbackVector::CreatePushAppliedArgumentsVector(isolate);
     construct->shared()->set_feedback_vector(*feedback_vector);
     isolate->native_context()->set_reflect_construct(*construct);
   }
+
+  Handle<JSObject> iterator_prototype;
+
+  {
+    PrototypeIterator iter(
+        isolate->native_context()->generator_object_prototype_map());
+    iter.Advance();  // Advance to the prototype of generator_object_prototype.
+    iterator_prototype = Handle<JSObject>(iter.GetCurrent<JSObject>());
+
+    JSObject::AddProperty(container, isolate->factory()->InternalizeUtf8String(
+                                         "IteratorPrototype"),
+                          iterator_prototype, NONE);
+  }
+
+  {
+    PrototypeIterator iter(
+        isolate->native_context()->sloppy_generator_function_map());
+    Handle<JSObject> generator_function_prototype(iter.GetCurrent<JSObject>());
+
+    JSObject::AddProperty(container, isolate->factory()->InternalizeUtf8String(
+                                         "GeneratorFunctionPrototype"),
+                          generator_function_prototype, NONE);
+
+    static const bool kUseStrictFunctionMap = true;
+    Handle<JSFunction> generator_function_function =
+        InstallFunction(container, "GeneratorFunction", JS_FUNCTION_TYPE,
+                        JSFunction::kSize, generator_function_prototype,
+                        Builtins::kIllegal, kUseStrictFunctionMap);
+    generator_function_function->initial_map()->set_is_callable();
+  }
+
+  {  // -- S e t I t e r a t o r
+    Handle<JSObject> set_iterator_prototype =
+        isolate->factory()->NewJSObject(isolate->object_function(), TENURED);
+    SetObjectPrototype(set_iterator_prototype, iterator_prototype);
+    Handle<JSFunction> set_iterator_function = InstallFunction(
+        container, "SetIterator", JS_SET_ITERATOR_TYPE, JSSetIterator::kSize,
+        set_iterator_prototype, Builtins::kIllegal);
+    isolate->native_context()->set_set_iterator_map(
+        set_iterator_function->initial_map());
+  }
+
+  {  // -- M a p I t e r a t o r
+    Handle<JSObject> map_iterator_prototype =
+        isolate->factory()->NewJSObject(isolate->object_function(), TENURED);
+    SetObjectPrototype(map_iterator_prototype, iterator_prototype);
+    Handle<JSFunction> map_iterator_function = InstallFunction(
+        container, "MapIterator", JS_MAP_ITERATOR_TYPE, JSMapIterator::kSize,
+        map_iterator_prototype, Builtins::kIllegal);
+    isolate->native_context()->set_map_iterator_map(
+        map_iterator_function->initial_map());
+  }
 }
 
 
 void Bootstrapper::ExportExperimentalFromRuntime(Isolate* isolate,
                                                  Handle<JSObject> container) {
   HandleScope scope(isolate);
 
 #define INITIALIZE_FLAG(FLAG)                                         \
   {                                                                   \
     Handle<String> name =                                             \
         isolate->factory()->NewStringFromAsciiChecked(#FLAG);         \
     JSObject::AddProperty(container, name,                            \
                           isolate->factory()->ToBoolean(FLAG), NONE); \
   }
 
   INITIALIZE_FLAG(FLAG_harmony_regexps)
   INITIALIZE_FLAG(FLAG_harmony_unicode_regexps)
   INITIALIZE_FLAG(FLAG_harmony_tostring)
+  INITIALIZE_FLAG(FLAG_harmony_tolength)
 
 #undef INITIALIZE_FLAG
 }
 
 
 #define EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(id) \
   void Genesis::InitializeGlobal_##id() {}
 
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_modules)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_array_includes)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_proxies)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_sloppy)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_sloppy_function)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_sloppy_let)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_rest_parameters)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_default_parameters)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_spread_calls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_destructuring)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_object_observe)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_spread_arrays)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_new_target)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_concat_spreadable)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_regexps)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_unicode_regexps)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tostring)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_completion)
-
-
-void Genesis::InitializeGlobal_harmony_tolength() {
-  Handle<JSObject> builtins(native_context()->builtins());
-  Handle<Object> flag(factory()->ToBoolean(FLAG_harmony_tolength));
-  Runtime::SetObjectProperty(isolate(), builtins,
-                             factory()->harmony_tolength_string(), flag,
-                             STRICT).Assert();
-}
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tolength)
 
 
 static void SimpleInstallFunction(Handle<JSObject>& base, const char* name,
                                   Builtins::Name call, int len, bool adapt) {
   Handle<JSFunction> fun =
       InstallFunction(base, name, JS_OBJECT_TYPE, JSObject::kHeaderSize,
                       MaybeHandle<JSObject>(), call);
   if (adapt) {
     fun->shared()->set_internal_formal_parameter_count(len);
   } else {
@@ skipping 170 matching lines @@
   int builtin_index = Natives::GetDebuggerCount();
   // Only run prologue.js and runtime.js at this point.
   DCHECK_EQ(builtin_index, Natives::GetIndex("prologue"));
   if (!Bootstrapper::CompileBuiltin(isolate(), builtin_index++)) return false;
   DCHECK_EQ(builtin_index, Natives::GetIndex("runtime"));
   if (!Bootstrapper::CompileBuiltin(isolate(), builtin_index++)) return false;
 
   // A thin context is ready at this point.
   if (context_type == THIN_CONTEXT) return true;
 
-  if (FLAG_expose_natives_as != NULL) {
-    Handle<String> utils_key = factory()->NewStringFromAsciiChecked("utils");
-    JSObject::AddProperty(builtins, utils_key, utils, NONE);
-  }
-
   {  // -- S c r i p t
     // Builtin functions for Script.
     Handle<JSFunction> script_fun = InstallFunction(
         builtins, "Script", JS_VALUE_TYPE, JSValue::kSize,
         isolate()->initial_object_prototype(), Builtins::kIllegal);
     Handle<JSObject> prototype =
         factory()->NewJSObject(isolate()->object_function(), TENURED);
     Accessors::FunctionSetPrototype(script_fun, prototype).Assert();
     native_context()->set_script_function(*script_fun);
 
@@ skipping 156 matching lines @@
   {
     HandleScope scope(isolate());
     Handle<JSObject> utils =
         Handle<JSObject>::cast(isolate()->natives_utils_object());
     Handle<JSFunction> array_function =
         InstallInternalArray(utils, "InternalArray", FAST_HOLEY_ELEMENTS);
     native_context()->set_internal_array_function(*array_function);
     InstallInternalArray(utils, "InternalPackedArray", FAST_ELEMENTS);
   }
 
-  {  // -- S e t I t e r a t o r
-    Handle<JSFunction> set_iterator_function = InstallFunction(
-        builtins, "SetIterator", JS_SET_ITERATOR_TYPE, JSSetIterator::kSize,
-        isolate()->initial_object_prototype(), Builtins::kIllegal);
-    native_context()->set_set_iterator_map(
-        set_iterator_function->initial_map());
-  }
-
-  {  // -- M a p I t e r a t o r
-    Handle<JSFunction> map_iterator_function = InstallFunction(
-        builtins, "MapIterator", JS_MAP_ITERATOR_TYPE, JSMapIterator::kSize,
-        isolate()->initial_object_prototype(), Builtins::kIllegal);
-    native_context()->set_map_iterator_map(
-        map_iterator_function->initial_map());
-  }
-
-  {
-    // Create generator meta-objects and install them on the builtins object.
-    Handle<JSObject> builtins(native_context()->builtins());
-    Handle<JSObject> iterator_prototype =
-        factory()->NewJSObject(isolate()->object_function(), TENURED);
-    Handle<JSObject> generator_object_prototype =
-        factory()->NewJSObject(isolate()->object_function(), TENURED);
-    Handle<JSObject> generator_function_prototype =
-        factory()->NewJSObject(isolate()->object_function(), TENURED);
-    SetObjectPrototype(generator_object_prototype, iterator_prototype);
-    JSObject::AddProperty(
-        builtins, factory()->InternalizeUtf8String("$iteratorPrototype"),
-        iterator_prototype,
-        static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY));
-    JSObject::AddProperty(
-        builtins,
-        factory()->InternalizeUtf8String("GeneratorFunctionPrototype"),
-        generator_function_prototype,
-        static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY));
-
-    JSObject::AddProperty(
-        generator_function_prototype,
-        factory()->InternalizeUtf8String("prototype"),
-        generator_object_prototype,
-        static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY));
-
-    static const bool kUseStrictFunctionMap = true;
-    Handle<JSFunction> generator_function_function =
-        InstallFunction(builtins, "GeneratorFunction", JS_FUNCTION_TYPE,
-                        JSFunction::kSize, generator_function_prototype,
-                        Builtins::kIllegal, kUseStrictFunctionMap);
-    generator_function_function->initial_map()->set_is_callable();
-
-    // Create maps for generator functions and their prototypes.  Store those
-    // maps in the native context. The "prototype" property descriptor is
-    // writable, non-enumerable, and non-configurable (as per ES6 draft
-    // 04-14-15, section 25.2.4.3).
-    Handle<Map> strict_function_map(strict_function_map_writable_prototype_);
-    // Generator functions do not have "caller" or "arguments" accessors.
-    Handle<Map> sloppy_generator_function_map =
-        Map::Copy(strict_function_map, "SloppyGeneratorFunction");
-    Map::SetPrototype(sloppy_generator_function_map,
-                      generator_function_prototype);
-    native_context()->set_sloppy_generator_function_map(
-        *sloppy_generator_function_map);
-
-    Handle<Map> strict_generator_function_map =
-        Map::Copy(strict_function_map, "StrictGeneratorFunction");
-    Map::SetPrototype(strict_generator_function_map,
-                      generator_function_prototype);
-    native_context()->set_strict_generator_function_map(
-        *strict_generator_function_map);
-
-    Handle<Map> strong_function_map(native_context()->strong_function_map());
-    Handle<Map> strong_generator_function_map =
-        Map::Copy(strong_function_map, "StrongGeneratorFunction");
-    Map::SetPrototype(strong_generator_function_map,
-                      generator_function_prototype);
-    native_context()->set_strong_generator_function_map(
-        *strong_generator_function_map);
-
-    Handle<JSFunction> object_function(native_context()->object_function());
-    Handle<Map> generator_object_prototype_map = Map::Create(isolate(), 0);
-    Map::SetPrototype(generator_object_prototype_map,
-                      generator_object_prototype);
-    native_context()->set_generator_object_prototype_map(
-        *generator_object_prototype_map);
-  }
-
-  if (FLAG_disable_native_files) {
-    PrintF("Warning: Running without installed natives!\n");
-    return true;
-  }
-
   // Run the rest of the native scripts.
   while (builtin_index < Natives::GetBuiltinsCount()) {
     if (!Bootstrapper::CompileBuiltin(isolate(), builtin_index++)) return false;
   }
 
   if (!CallUtilsFunction(isolate(), "PostNatives")) return false;
 
   auto function_cache =
       ObjectHashTable::New(isolate(), ApiNatives::kInitialFunctionCacheSize,
                            USE_CUSTOM_MINIMUM_CAPACITY);
@@ skipping 397 matching lines @@
   Handle<JSGlobalObject> global(JSGlobalObject::cast(
       native_context->global_object()));
 
   Handle<JSObject> Error = Handle<JSObject>::cast(
       Object::GetProperty(isolate, global, "Error").ToHandleChecked());
   Handle<String> name =
       factory->InternalizeOneByteString(STATIC_CHAR_VECTOR("stackTraceLimit"));
   Handle<Smi> stack_trace_limit(Smi::FromInt(FLAG_stack_trace_limit), isolate);
   JSObject::AddProperty(Error, name, stack_trace_limit, NONE);
 
-  // Expose the natives in global if a name for it is specified.
-  if (FLAG_expose_natives_as != NULL && strlen(FLAG_expose_natives_as) != 0) {
-    Handle<String> natives_key =
-        factory->InternalizeUtf8String(FLAG_expose_natives_as);
-    uint32_t dummy_index;
-    if (natives_key->AsArrayIndex(&dummy_index)) return true;
-    Handle<JSBuiltinsObject> natives(global->builtins());
-    JSObject::AddProperty(global, natives_key, natives, DONT_ENUM);
-  }
-
   // Expose the debug global object in global if a name for it is specified.
   if (FLAG_expose_debug_as != NULL && strlen(FLAG_expose_debug_as) != 0) {
     // If loading fails we just bail out without installing the
     // debugger but without tanking the whole context.
     Debug* debug = isolate->debug();
     if (!debug->Load()) return true;
     Handle<Context> debug_context = debug->debug_context();
     // Set the security token for the debugger context to the same as
     // the shell native context to allow calling between these (otherwise
     // exposing debug global object doesn't make much sense).
@@ skipping 423 matching lines @@
         native_context()->global_proxy());
     HookUpGlobalThisBinding(outdated_contexts);
 
     if (!ConfigureGlobalObjects(global_proxy_template)) return;
   } else {
     // We get here if there was no context snapshot.
     CreateRoots();
     Handle<JSFunction> empty_function = CreateEmptyFunction(isolate);
     CreateStrictModeFunctionMaps(empty_function);
     CreateStrongModeFunctionMaps(empty_function);
+    CreateIteratorMaps();
     Handle<GlobalObject> global_object =
         CreateNewGlobals(global_proxy_template, global_proxy);
     HookUpGlobalProxy(global_object, global_proxy);
     InitializeGlobal(global_object, empty_function, context_type);
     InitializeNormalizedMapCaches();
 
     if (!InstallNatives(context_type)) return;
 
     MakeFunctionInstancePrototypeWritable();
 
     if (context_type != THIN_CONTEXT) {
       if (!InstallExtraNatives()) return;
       if (!ConfigureGlobalObjects(global_proxy_template)) return;
     }
     isolate->counters()->contexts_created_from_scratch()->Increment();
   }
 
   // Install experimental natives. Do not include them into the
   // snapshot as we should be able to turn them off at runtime. Re-installing
   // them after they have already been deserialized would also fail.
   if (context_type == FULL_CONTEXT) {
     if (!isolate->serializer_enabled()) {
       InitializeExperimentalGlobal();
       if (!InstallExperimentalNatives()) return;
 
       if (FLAG_experimental_extras) {
         if (!InstallExperimentalExtraNatives()) return;
       }
-
-      // By now the utils object is useless and can be removed.
-      native_context()->set_natives_utils_object(
-          isolate->heap()->undefined_value());
     }
     // The serializer cannot serialize typed arrays. Reset those typed arrays
     // for each new context.
     InitializeBuiltinTypedArrays();
   } else if (context_type == DEBUG_CONTEXT) {
     DCHECK(!isolate->serializer_enabled());
     InitializeExperimentalGlobal();
     if (!InstallDebuggerNatives()) return;
   }
 
+  ConfigureUtilsObject(context_type);
+
   // Check that the script context table is empty except for the 'this' binding.
   // We do not need script contexts for native scripts.
   if (!FLAG_global_var_shortcuts) {
     DCHECK_EQ(1, native_context()->script_context_table()->used());
   }
 
   result_ = native_context();
 }
 
 
@@ skipping 20 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8