Reland "Lazily register prototype users..."

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 1823 matching lines @@
   // Sets the property value in a normalized object given (key, value, details).
   // Handles the special representation of JS global objects.
   static void SetNormalizedProperty(Handle<JSObject> object,
                                     Handle<Name> key,
                                     Handle<Object> value,
                                     PropertyDetails details);
 
   static void OptimizeAsPrototype(Handle<JSObject> object,
                                   PrototypeOptimizationMode mode);
   static void ReoptimizeIfPrototype(Handle<JSObject> object);
-  static void RegisterPrototypeUser(Handle<JSObject> prototype,
-                                    Handle<HeapObject> user);
-  static void UnregisterPrototypeUser(Handle<JSObject> prototype,
+  static void LazyRegisterPrototypeUser(Handle<Map> user, Isolate* isolate);
+  static bool RegisterPrototypeUserIfNotRegistered(Handle<JSObject> prototype,
+                                                   Handle<HeapObject> user,
+                                                   Isolate* isolate);
+  static bool UnregisterPrototypeUser(Handle<JSObject> prototype,
                                       Handle<HeapObject> user);
   static void InvalidatePrototypeChains(Map* map);
 
   // Retrieve interceptors.
   InterceptorInfo* GetNamedInterceptor();
   InterceptorInfo* GetIndexedInterceptor();
 
   // Used from JSReceiver.
   MUST_USE_RESULT static Maybe<PropertyAttributes>
       GetPropertyAttributesWithInterceptor(Handle<JSObject> holder,
@@ skipping 757 matching lines @@
 };
 
 
 class WeakFixedArray : public FixedArray {
  public:
   enum SearchForDuplicates { kAlwaysAdd, kAddIfNotFound };
 
   // If |maybe_array| is not a WeakFixedArray, a fresh one will be allocated.
   static Handle<WeakFixedArray> Add(
       Handle<Object> maybe_array, Handle<HeapObject> value,
-      SearchForDuplicates search_for_duplicates = kAlwaysAdd);
+      SearchForDuplicates search_for_duplicates = kAlwaysAdd,
+      bool* was_present = NULL);
 
-  void Remove(Handle<HeapObject> value);
+  // Returns true if an entry was found and removed.
+  bool Remove(Handle<HeapObject> value);
 
   void Compact();
 
   inline Object* Get(int index) const;
   inline int Length() const;
 
   static Object* Empty() { return Smi::FromInt(0); }
 
   DECLARE_CAST(WeakFixedArray)
 
@@ skipping 3200 matching lines @@
   // any cleared weak cell.
   bool Compact();
   static int Grow(int number_of_entries) {
     if (number_of_entries < 5) return number_of_entries + 1;
     return number_of_entries * 5 / 4;
   }
   static const int kCodesStartIndex = kGroupCount;
 };
 
 
+class PrototypeInfo;
+
+
 // All heap objects have a Map that describes their structure.
 //  A Map contains information about:
 //  - Size information about the object
 //  - How to iterate over an object (for garbage collection)
 class Map: public HeapObject {
  public:
   // Instance size.
   // Size in bytes or kVariableSizeSentinel if instances do not have
   // a fixed size.
   inline int instance_size();
@@ skipping 187 matching lines @@
 
   inline FixedArrayBase* GetInitialElements();
 
   // [raw_transitions]: Provides access to the transitions storage field.
   // Don't call set_raw_transitions() directly to overwrite transitions, use
   // the TransitionArray::ReplaceTransitions() wrapper instead!
   DECL_ACCESSORS(raw_transitions, Object)
   // [prototype_info]: Per-prototype metadata. Aliased with transitions
   // (which prototype maps don't have).
   DECL_ACCESSORS(prototype_info, Object)
+  // PrototypeInfo is created lazily using this helper (which installs it on
+  // the given prototype's map).
+  static Handle<PrototypeInfo> GetOrCreatePrototypeInfo(
+      Handle<JSObject> prototype, Isolate* isolate);
 
   // [prototype chain validity cell]: Associated with a prototype object,
   // stored in that object's map's PrototypeInfo, indicates that prototype
   // chains through this object are currently valid. The cell will be
   // invalidated and replaced when the prototype chain changes.
   static Handle<Cell> GetOrCreatePrototypeChainValidityCell(Handle<Map> map,
                                                             Isolate* isolate);
   static const int kPrototypeChainValid = 0;
   static const int kPrototypeChainInvalid = 1;
 
@@ skipping 52 matching lines @@
 
   // Returns true if map has a non-empty stub code cache.
   inline bool has_code_cache();
 
   // [prototype]: implicit prototype object.
   DECL_ACCESSORS(prototype, Object)
   // TODO(jkummerow): make set_prototype private.
   static void SetPrototype(
       Handle<Map> map, Handle<Object> prototype,
       PrototypeOptimizationMode proto_mode = FAST_PROTOTYPE);
-  static bool ShouldRegisterAsPrototypeUser(Handle<Map> map,
-                                            Handle<JSObject> prototype);
-  bool CanUseOptimizationsBasedOnPrototypeRegistry();
 
   // [constructor]: points back to the function responsible for this map.
   // The field overlaps with the back pointer. All maps in a transition tree
   // have the same constructor, so maps with back pointers can walk the
   // back pointer chain until they find the map holding their constructor.
   DECL_ACCESSORS(constructor_or_backpointer, Object)
   inline Object* GetConstructor() const;
   inline void SetConstructor(Object* constructor,
                              WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
   // [back pointer]: points back to the parent map from which a transition
@@ skipping 4954 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_