[ic] Data handlers for loads of non-existent properties.

src/ic/handler-configuration.h

 // Copyright 2016 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_IC_HANDLER_CONFIGURATION_H_
 #define V8_IC_HANDLER_CONFIGURATION_H_
 
 #include "src/elements-kind.h"
 #include "src/field-index.h"
 #include "src/globals.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
 
 // A set of bit fields representing Smi handlers for loads.
 class LoadHandler {
  public:
-  enum Kind { kForElements, kForFields, kForConstants };
+  enum Kind { kForElements, kForFields, kForConstants, kForNonExistent };
   class KindBits : public BitField<Kind, 0, 2> {};
 
   // Defines whether negative lookup check should be done on receiver object.
-  // Applicable to kForFields and kForConstants kinds only when loading value
-  // from prototype chain. Ignored when loading from holder.
+  // Applicable to kForFields, kForConstants and kForNonExistent kinds only when
+  // loading value from prototype chain. Ignored when loading from holder.
   class DoNegativeLookupOnReceiverBits
       : public BitField<bool, KindBits::kNext, 1> {};
 
   //
   // Encoding when KindBits contains kForConstants.
   //
 
   // +2 here is because each descriptor entry occupies 3 slots in array.
   class DescriptorValueIndexBits
       : public BitField<unsigned, DoNegativeLookupOnReceiverBits::kNext,
@@ skipping 44 matching lines @@
                                          FieldIndex field_index);
 
   // Creates a Smi-handler for loading a constant from fast object.
   static inline Handle<Object> LoadConstant(Isolate* isolate, int descriptor);
 
   // Sets DoNegativeLookupOnReceiverBits in given Smi-handler. The receiver
   // check is a part of a prototype chain check.
   static inline Handle<Object> EnableNegativeLookupOnReceiver(
       Isolate* isolate, Handle<Object> smi_handler);
 
+  // Creates a Smi-handler for loading a non-existent property. Works only as
+  // a part of prototype chain check.
+  static inline Handle<Object> LoadNonExistent(
+      Isolate* isolate, bool do_negative_lookup_on_receiver);
+
   // Creates a Smi-handler for loading an element.
   static inline Handle<Object> LoadElement(Isolate* isolate,
                                            ElementsKind elements_kind,
                                            bool convert_hole_to_undefined,
                                            bool is_js_array);
 };
 
 // A set of bit fields representing Smi handlers for stores.
 class StoreHandler {
  public:
@@ skipping 22 matching lines @@
   // Creates a Smi-handler for storing a field to fast object.
   static inline Handle<Object> StoreField(Isolate* isolate, int descriptor,
                                           FieldIndex field_index,
                                           Representation representation);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IC_HANDLER_CONFIGURATION_H_