[runtime] Don't cache the holder_map_ in the LookupIterator, it's faster.

src/lookup.h

 // 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.
 
 #ifndef V8_LOOKUP_H_
 #define V8_LOOKUP_H_
 
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/objects.h"
@@ skipping 38 matching lines @@
       : configuration_(ComputeConfiguration(configuration, name)),
         state_(NOT_FOUND),
         interceptor_state_(InterceptorState::kUninitialized),
         property_details_(PropertyDetails::Empty()),
         isolate_(name->GetIsolate()),
         name_(Name::Flatten(name)),
         // kMaxUInt32 isn't a valid index.
         index_(kMaxUInt32),
         receiver_(receiver),
         holder_(GetRoot(isolate_, receiver)),
-        holder_map_(holder_->map(), isolate_),
         initial_holder_(holder_),
         number_(DescriptorArray::kNotFound) {
 #ifdef DEBUG
     uint32_t index;  // Assert that the name is not an array index.
     DCHECK(!name->AsArrayIndex(&index));
 #endif  // DEBUG
     Next();
   }
 
   LookupIterator(Handle<Object> receiver, Handle<Name> name,
                  Handle<JSReceiver> holder,
                  Configuration configuration = DEFAULT)
       : configuration_(ComputeConfiguration(configuration, name)),
         state_(NOT_FOUND),
         interceptor_state_(InterceptorState::kUninitialized),
         property_details_(PropertyDetails::Empty()),
         isolate_(name->GetIsolate()),
         name_(Name::Flatten(name)),
         // kMaxUInt32 isn't a valid index.
         index_(kMaxUInt32),
         receiver_(receiver),
         holder_(holder),
-        holder_map_(holder_->map(), isolate_),
         initial_holder_(holder_),
         number_(DescriptorArray::kNotFound) {
 #ifdef DEBUG
     uint32_t index;  // Assert that the name is not an array index.
     DCHECK(!name->AsArrayIndex(&index));
 #endif  // DEBUG
     Next();
   }
 
   LookupIterator(Isolate* isolate, Handle<Object> receiver, uint32_t index,
                  Configuration configuration = DEFAULT)
       : configuration_(configuration),
         state_(NOT_FOUND),
         interceptor_state_(InterceptorState::kUninitialized),
         property_details_(PropertyDetails::Empty()),
         isolate_(isolate),
         name_(),
         index_(index),
         receiver_(receiver),
         holder_(GetRoot(isolate, receiver, index)),
-        holder_map_(holder_->map(), isolate_),
         initial_holder_(holder_),
         number_(DescriptorArray::kNotFound) {
     // kMaxUInt32 isn't a valid index.
     DCHECK_NE(kMaxUInt32, index_);
     Next();
   }
 
   LookupIterator(Isolate* isolate, Handle<Object> receiver, uint32_t index,
                  Handle<JSReceiver> holder,
                  Configuration configuration = DEFAULT)
       : configuration_(configuration),
         state_(NOT_FOUND),
         interceptor_state_(InterceptorState::kUninitialized),
         property_details_(PropertyDetails::Empty()),
         isolate_(isolate),
         name_(),
         index_(index),
         receiver_(receiver),
         holder_(holder),
-        holder_map_(holder_->map(), isolate_),
         initial_holder_(holder_),
         number_(DescriptorArray::kNotFound) {
     // kMaxUInt32 isn't a valid index.
     DCHECK_NE(kMaxUInt32, index_);
     Next();
   }
 
   static LookupIterator PropertyOrElement(
       Isolate* isolate, Handle<Object> receiver, Handle<Name> name,
       Configuration configuration = DEFAULT) {
@@ skipping 48 matching lines @@
   void Next();
   void NotFound() {
     has_property_ = false;
     state_ = NOT_FOUND;
   }
 
   Heap* heap() const { return isolate_->heap(); }
   Factory* factory() const { return isolate_->factory(); }
   Handle<Object> GetReceiver() const { return receiver_; }
   Handle<JSObject> GetStoreTarget() const;
-  bool is_dictionary_holder() const { return holder_map_->is_dictionary_map(); }
+  bool is_dictionary_holder() const { return !holder_->HasFastProperties(); }
   Handle<Map> transition_map() const {
     DCHECK_EQ(TRANSITION, state_);
     return Handle<Map>::cast(transition_);
   }
   template <class T>
   Handle<T> GetHolder() const {
     DCHECK(IsFound());
     return Handle<T>::cast(holder_);
   }
 
@@ skipping 51 matching lines @@
   int GetConstantIndex() const;
   Handle<PropertyCell> GetPropertyCell() const;
   Handle<Object> GetAccessors() const;
   inline Handle<InterceptorInfo> GetInterceptor() const {
     DCHECK_EQ(INTERCEPTOR, state_);
     return handle(GetInterceptor(JSObject::cast(*holder_)), isolate_);
   }
   Handle<Object> GetDataValue() const;
   void WriteDataValue(Handle<Object> value);
   void InternalizeName();
-  void ReloadHolderMap();
 
  private:
   enum class InterceptorState {
     kUninitialized,
     kSkipNonMasking,
     kProcessNonMasking
   };
 
   Handle<Map> GetReceiverMap() const;
 
@@ skipping 13 matching lines @@
     return holder->GetNamedInterceptor();
   }
 
   bool check_hidden() const { return (configuration_ & kHidden) != 0; }
   bool check_interceptor() const {
     return (configuration_ & kInterceptor) != 0;
   }
   int descriptor_number() const {
     DCHECK(!IsElement());
     DCHECK(has_property_);
-    DCHECK(!holder_map_->is_dictionary_map());
+    DCHECK(holder_->HasFastProperties());
     return number_;
   }
   int dictionary_entry() const {
     DCHECK(!IsElement());
     DCHECK(has_property_);
-    DCHECK(holder_map_->is_dictionary_map());
+    DCHECK(!holder_->HasFastProperties());
     return number_;
   }
 
   static Configuration ComputeConfiguration(
       Configuration configuration, Handle<Name> name) {
     if (name->IsPrivate()) {
       return static_cast<Configuration>(configuration &
                                         HIDDEN_SKIP_INTERCEPTOR);
     } else {
       return configuration;
@@ skipping 17 matching lines @@
   State state_;
   bool has_property_;
   InterceptorState interceptor_state_;
   PropertyDetails property_details_;
   Isolate* const isolate_;
   Handle<Name> name_;
   uint32_t index_;
   Handle<Object> transition_;
   const Handle<Object> receiver_;
   Handle<JSReceiver> holder_;
-  Handle<Map> holder_map_;
   const Handle<JSReceiver> initial_holder_;
   uint32_t number_;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_LOOKUP_H_