Fasterify JSObject::UnregisterPrototypeUser

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 1888 matching lines @@
                                    PropertyAttributes attributes);
   static void SetDictionaryArgumentsElement(Handle<JSObject> object,
                                             uint32_t index,
                                             Handle<Object> value,
                                             PropertyAttributes attributes);
 
   static void OptimizeAsPrototype(Handle<JSObject> object,
                                   PrototypeOptimizationMode mode);
   static void ReoptimizeIfPrototype(Handle<JSObject> object);
   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 bool UnregisterPrototypeUser(Handle<Map> user, Isolate* isolate);
   static void InvalidatePrototypeChains(Map* map);
 
   // Retrieve interceptors.
   InterceptorInfo* GetNamedInterceptor();
   InterceptorInfo* GetIndexedInterceptor();
 
   // Used from JSReceiver.
   MUST_USE_RESULT static Maybe<PropertyAttributes>
   GetPropertyAttributesWithInterceptor(LookupIterator* it);
   MUST_USE_RESULT static Maybe<PropertyAttributes>
@@ skipping 600 matching lines @@
   DECLARE_PRINTER(FixedDoubleArray)
   DECLARE_VERIFIER(FixedDoubleArray)
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(FixedDoubleArray);
 };
 
 
 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,
-      bool* was_present = NULL);
+  // This function does not check if the value exists already, callers must
+  // ensure this themselves if necessary.
+  static Handle<WeakFixedArray> Add(Handle<Object> maybe_array,
+                                    Handle<HeapObject> value,
+                                    int* assigned_index = NULL);
 
   // Returns true if an entry was found and removed.
   bool Remove(Handle<HeapObject> value);
 
   void Compact();
+  // Special version of Compact() for WeakFixedArrays that are used as
+  // prototype user registries. Updates the contained maps' remembered index.
+  void CompactPrototypeUserList();

[Yang, 2015/08/07 21:37:24]

Not sure if this should live on Map instead.

[Jakob Kummerow, 2015/08/08 12:39:32]

Moved it to JSObject where all the other prototype registration stuff lives.

 
   inline Object* Get(int index) const;
   inline void Clear(int index);
   inline int Length() const;
 
   inline bool IsEmptySlot(int index) const;
   static Object* Empty() { return Smi::FromInt(0); }
 
   DECLARE_CAST(WeakFixedArray)
 
@@ skipping 2905 matching lines @@
   // 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);
+  static Handle<PrototypeInfo> GetOrCreatePrototypeInfo(
+      Handle<Map> prototype_map, 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 549 matching lines @@
   static const int kSize = kValueOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(Box);
 };
 
 
 // Container for metadata stored on each prototype map.
 class PrototypeInfo : public Struct {
  public:
+  static const int UNREGISTERED = -1;
+
   // [prototype_users]: WeakFixedArray containing maps using this prototype,
   // or Smi(0) if uninitialized.
   DECL_ACCESSORS(prototype_users, Object)
+  // [registry_slot]: Slot in prototype's user registry where this user
+  // is stored. Returns UNREGISTERED if this prototype has not been registered.
+  inline int registry_slot() const;
+  inline void set_registry_slot(int slot);
   // [validity_cell]: Cell containing the validity bit for prototype chains
   // going through this object, or Smi(0) if uninitialized.
   DECL_ACCESSORS(validity_cell, Object)
   // [constructor_name]: User-friendly name of the original constructor.
   DECL_ACCESSORS(constructor_name, Object)
 
   DECLARE_CAST(PrototypeInfo)
 
   // Dispatched behavior.
   DECLARE_PRINTER(PrototypeInfo)
   DECLARE_VERIFIER(PrototypeInfo)
 
   static const int kPrototypeUsersOffset = HeapObject::kHeaderSize;
-  static const int kValidityCellOffset = kPrototypeUsersOffset + kPointerSize;
+  static const int kRegistrySlotOffset = kPrototypeUsersOffset + kPointerSize;
+  static const int kValidityCellOffset = kRegistrySlotOffset + kPointerSize;
   static const int kConstructorNameOffset = kValidityCellOffset + kPointerSize;
   static const int kSize = kConstructorNameOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PrototypeInfo);
 };
 
 
 // Script describes a script which has been added to the VM.
 class Script: public Struct {
@@ skipping 4478 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_