[runtime] Avoid @@isConcatSpreadable lookup for fast path Array.prototype.concat

src/isolate.h

 // Copyright 2012 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.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <queue>
 #include <set>
 
@@ skipping 942 matching lines @@
     date_cache_ = date_cache;
   }
 
   ErrorToStringHelper* error_tostring_helper() {
     return &error_tostring_helper_;
   }
 
   Map* get_initial_js_array_map(ElementsKind kind,
                                 Strength strength = Strength::WEAK);
 
-  static const int kArrayProtectorValid = 1;
-  static const int kArrayProtectorInvalid = 0;
+  // The isConcatSpreadable protector is valid if there this property is

[Toon Verwaest, 2015/11/02 12:32:45]

valid if @@isConcatSpreadable is not present on ...

+  // not present on the Array prototype chain.
+  static const int kArrayIsConcatSpreadableProtectorValid = 1;
+  static const int kArrayIsConcatSpreadableProtectorInvalid = 0;
+  bool IsArrayIsConcatSpreadableSet();
 
+  void UpdateArrayIsConcatSpreadableProtectorOnAddProperty(
+      Handle<JSObject> object, Handle<Name> name);
+
+  // The elements protector is valid if there are not additional elements

[Toon Verwaest, 2015/11/02 12:32:45]

not -> no

+  // on the Array prototype chain.
+  static const int kArrayElementsProtectorValid = 1;
+  static const int kArrayElementsProtectorInvalid = 0;
   bool IsFastArrayConstructorPrototypeChainIntact();
 
   // On intent to set an element in object, make sure that appropriate
   // notifications occur if the set is on the elements of the array or
   // object prototype. Also ensure that changes to prototype chain between
   // Array and Object fire notifications.
   void UpdateArrayProtectorOnSetElement(Handle<JSObject> object);
   void UpdateArrayProtectorOnSetLength(Handle<JSObject> object) {
     UpdateArrayProtectorOnSetElement(object);
   }
@@ skipping 111 matching lines @@
 
   FutexWaitListNode* futex_wait_list_node() { return &futex_wait_list_node_; }
 
   void RegisterCancelableTask(Cancelable* task);
   void RemoveCancelableTask(Cancelable* task);
 
   interpreter::Interpreter* interpreter() const { return interpreter_; }
 
  protected:
   explicit Isolate(bool enable_serializer);
+  Context* ContextForArrayOrObjectPrototype(Handle<JSObject> object);
 
  private:
   friend struct GlobalState;
   friend struct InitializeGlobalState;
   Handle<JSObject> SetUpSubregistry(Handle<JSObject> registry, Handle<Map> map,
                                     const char* name);
 
   // These fields are accessed through the API, offsets must be kept in sync
   // with v8::internal::Internals (in include/v8.h) constants. This is also
   // verified in Isolate::Init() using runtime checks.
@@ skipping 449 matching lines @@
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_H_