Use the syntax of a property addition as a hint for controlling the fast-mode vs. dictionary mode h…

src/objects.h

 // 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 1335 matching lines @@
 // JSReceiver includes types on which properties can be defined, i.e.,
 // JSObject and JSProxy.
 class JSReceiver: public HeapObject {
  public:
   enum DeleteMode {
     NORMAL_DELETION,
     STRICT_DELETION,
     FORCE_DELETION
   };
 
+  // A non-keyed store is of the form a.x = foo or a["x"] = foo whereas
+  // a keyed store is of the form a[expression] = foo.
+  enum StoreFromKeyed {
+    MAY_BE_STORE_FROM_KEYED,
+    CERTAINLY_NOT_STORE_FROM_KEYED
+  };
+
   // Casting.
   static inline JSReceiver* cast(Object* obj);
 
   static Handle<Object> SetProperty(Handle<JSReceiver> object,
                                     Handle<String> key,
                                     Handle<Object> value,
                                     PropertyAttributes attributes,
                                     StrictModeFlag strict_mode);
   // Can cause GC.
-  MUST_USE_RESULT MaybeObject* SetProperty(String* key,
-                                           Object* value,
-                                           PropertyAttributes attributes,
-                                           StrictModeFlag strict_mode);
-  MUST_USE_RESULT MaybeObject* SetProperty(LookupResult* result,
-                                           String* key,
-                                           Object* value,
-                                           PropertyAttributes attributes,
-                                           StrictModeFlag strict_mode);
+  MUST_USE_RESULT MaybeObject* SetProperty(
+      String* key,
+      Object* value,
+      PropertyAttributes attributes,
+      StrictModeFlag strict_mode,
+      StoreFromKeyed store_from_keyed = MAY_BE_STORE_FROM_KEYED);
+  MUST_USE_RESULT MaybeObject* SetProperty(
+      LookupResult* result,
+      String* key,
+      Object* value,
+      PropertyAttributes attributes,
+      StrictModeFlag strict_mode,
+      StoreFromKeyed store_from_keyed = MAY_BE_STORE_FROM_KEYED);
   MUST_USE_RESULT MaybeObject* SetPropertyWithDefinedSetter(JSReceiver* setter,
                                                             Object* value);
 
   MUST_USE_RESULT MaybeObject* DeleteProperty(String* name, DeleteMode mode);
   MUST_USE_RESULT MaybeObject* DeleteElement(uint32_t index, DeleteMode mode);
 
   // Set the index'th array element.
   // Can cause GC, or return failure if GC is required.
   MUST_USE_RESULT MaybeObject* SetElement(uint32_t index,
                                           Object* value,
@@ skipping 133 matching lines @@
 
   MUST_USE_RESULT MaybeObject* GetPropertyWithCallback(Object* receiver,
                                                        Object* structure,
                                                        String* name);
 
   // Can cause GC.
   MUST_USE_RESULT MaybeObject* SetPropertyForResult(LookupResult* result,
                                            String* key,
                                            Object* value,
                                            PropertyAttributes attributes,
-                                           StrictModeFlag strict_mode);
+                                           StrictModeFlag strict_mode,
+                                           StoreFromKeyed store_mode);
   MUST_USE_RESULT MaybeObject* SetPropertyWithFailedAccessCheck(
       LookupResult* result,
       String* name,
       Object* value,
       bool check_prototype,
       StrictModeFlag strict_mode);
   MUST_USE_RESULT MaybeObject* SetPropertyWithCallback(
       Object* structure,
       String* name,
       Object* value,
@@ skipping 376 matching lines @@
 
   // Converts a descriptor of any other type to a real field,
   // backed by the properties array.  Descriptors of visible
   // types, such as CONSTANT_FUNCTION, keep their enumeration order.
   MUST_USE_RESULT MaybeObject* ConvertDescriptorToField(
       String* name,
       Object* new_value,
       PropertyAttributes attributes);
 
   // Add a property to a fast-case object.
-  MUST_USE_RESULT MaybeObject* AddFastProperty(String* name,
-                                               Object* value,
-                                               PropertyAttributes attributes);
+  MUST_USE_RESULT MaybeObject* AddFastProperty(
+      String* name,
+      Object* value,
+      PropertyAttributes attributes,
+      StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED);
 
   // Add a property to a slow-case object.
   MUST_USE_RESULT MaybeObject* AddSlowProperty(String* name,
                                                Object* value,
                                                PropertyAttributes attributes);
 
   // Add a property to an object.
-  MUST_USE_RESULT MaybeObject* AddProperty(String* name,
-                                           Object* value,
-                                           PropertyAttributes attributes,
-                                           StrictModeFlag strict_mode);
+  MUST_USE_RESULT MaybeObject* AddProperty(
+      String* name,
+      Object* value,
+      PropertyAttributes attributes,
+      StrictModeFlag strict_mode,
+      StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED);
 
   // Convert the object to use the canonical dictionary
   // representation. If the object is expected to have additional properties
   // added this number can be indicated to have the backing store allocated to
   // an initial capacity for holding these properties.
   static void NormalizeProperties(Handle<JSObject> object,
                                   PropertyNormalizationMode mode,
                                   int expected_additional_properties);
 
   MUST_USE_RESULT MaybeObject* NormalizeProperties(
@@ skipping 99 matching lines @@
     int number_of_slow_unused_elements_;
   };
 
   void IncrementSpillStatistics(SpillInformation* info);
 #endif
   Object* SlowReverseLookup(Object* value);
 
   // Maximal number of fast properties for the JSObject. Used to
   // restrict the number of map transitions to avoid an explosion in
   // the number of maps for objects used as dictionaries.
-  inline bool TooManyFastProperties(int properties);
+  inline bool TooManyFastProperties(int properties, StoreFromKeyed store_mode);
 
   // Maximal number of elements (numbered 0 .. kMaxElementCount - 1).
   // Also maximal value of JSArray's length property.
   static const uint32_t kMaxElementCount = 0xffffffffu;
 
   // Constants for heuristics controlling conversion of fast elements
   // to slow elements.
 
   // Maximal gap that can be introduced by adding an element beyond
   // the current elements length.
   static const uint32_t kMaxGap = 1024;
 
   // Maximal length of fast elements array that won't be checked for
   // being dense enough on expansion.
   static const int kMaxUncheckedFastElementsLength = 5000;
 
   // Same as above but for old arrays. This limit is more strict. We
   // don't want to be wasteful with long lived objects.
   static const int kMaxUncheckedOldFastElementsLength = 500;
 
   static const int kInitialMaxFastElementArray = 100000;
   static const int kFastPropertiesSoftLimit = 12;
-  static const int kMaxFastProperties = 32;
+  static const int kMaxFastProperties = 64;
   static const int kMaxInstanceSize = 255 * kPointerSize;
   // When extending the backing storage for property values, we increase
   // its size by more than the 1 entry necessary, so sequentially adding fields
   // to the same object requires fewer allocations and copies.
   static const int kFieldsAdded = 3;
 
   // Layout description.
   static const int kPropertiesOffset = HeapObject::kHeaderSize;
   static const int kElementsOffset = kPropertiesOffset + kPointerSize;
   static const int kHeaderSize = kElementsOffset + kPointerSize;
@@ skipping 6607 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_