Introduce a new AccessorPair type for handling JavaScript accessors.

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 89 matching lines @@
 //           - ExternalAsciiString
 //           - ExternalTwoByteString
 //       - HeapNumber
 //       - Code
 //       - Map
 //       - Oddball
 //       - Foreign
 //       - SharedFunctionInfo
 //       - Struct
 //         - AccessorInfo
+//         - AccessorPair
 //         - AccessCheckInfo
 //         - InterceptorInfo
 //         - CallHandlerInfo
 //         - TemplateInfo
 //           - FunctionTemplateInfo
 //           - ObjectTemplateInfo
 //         - Script
 //         - SignatureInfo
 //         - TypeSwitchInfo
 //         - DebugInfo
@@ skipping 148 matching lines @@
   V(EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE)                                         \
   V(EXTERNAL_SHORT_ARRAY_TYPE)                                                 \
   V(EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE)                                        \
   V(EXTERNAL_INT_ARRAY_TYPE)                                                   \
   V(EXTERNAL_UNSIGNED_INT_ARRAY_TYPE)                                          \
   V(EXTERNAL_FLOAT_ARRAY_TYPE)                                                 \
   V(EXTERNAL_PIXEL_ARRAY_TYPE)                                                 \
   V(FILLER_TYPE)                                                               \
                                                                                \
   V(ACCESSOR_INFO_TYPE)                                                        \
+  V(ACCESSOR_PAIR_TYPE)                                                        \
   V(ACCESS_CHECK_INFO_TYPE)                                                    \
   V(INTERCEPTOR_INFO_TYPE)                                                     \
   V(CALL_HANDLER_INFO_TYPE)                                                    \
   V(FUNCTION_TEMPLATE_INFO_TYPE)                                               \
   V(OBJECT_TEMPLATE_INFO_TYPE)                                                 \
   V(SIGNATURE_INFO_TYPE)                                                       \
   V(TYPE_SWITCH_INFO_TYPE)                                                     \
   V(SCRIPT_TYPE)                                                               \
   V(CODE_CACHE_TYPE)                                                           \
   V(POLYMORPHIC_CODE_CACHE_TYPE)                                               \
@@ skipping 127 matching lines @@
 // object type in this causes the compiler to generate most of the boilerplate
 // code for the class including allocation and garbage collection routines,
 // casts and predicates.  All you need to define is the class, methods and
 // object verification routines.  Easy, no?
 //
 // Note that for subtle reasons related to the ordering or numerical values of
 // type tags, elements in this list have to be added to the INSTANCE_TYPE_LIST
 // manually.
 #define STRUCT_LIST_ALL(V)                                                     \
   V(ACCESSOR_INFO, AccessorInfo, accessor_info)                                \
+  V(ACCESSOR_PAIR, AccessorPair, accessor_pair)                                \
   V(ACCESS_CHECK_INFO, AccessCheckInfo, access_check_info)                     \
   V(INTERCEPTOR_INFO, InterceptorInfo, interceptor_info)                       \
   V(CALL_HANDLER_INFO, CallHandlerInfo, call_handler_info)                     \
   V(FUNCTION_TEMPLATE_INFO, FunctionTemplateInfo, function_template_info)      \
   V(OBJECT_TEMPLATE_INFO, ObjectTemplateInfo, object_template_info)            \
   V(SIGNATURE_INFO, SignatureInfo, signature_info)                             \
   V(TYPE_SWITCH_INFO, TypeSwitchInfo, type_switch_info)                        \
   V(SCRIPT, Script, script)                                                    \
   V(CODE_CACHE, CodeCache, code_cache)                                         \
   V(POLYMORPHIC_CODE_CACHE, PolymorphicCodeCache, polymorphic_code_cache)
@@ skipping 133 matching lines @@
   EXTERNAL_INT_ARRAY_TYPE,
   EXTERNAL_UNSIGNED_INT_ARRAY_TYPE,
   EXTERNAL_FLOAT_ARRAY_TYPE,
   EXTERNAL_DOUBLE_ARRAY_TYPE,
   EXTERNAL_PIXEL_ARRAY_TYPE,  // LAST_EXTERNAL_ARRAY_TYPE
   FIXED_DOUBLE_ARRAY_TYPE,
   FILLER_TYPE,  // LAST_DATA_TYPE
 
   // Structs.
   ACCESSOR_INFO_TYPE,
+  ACCESSOR_PAIR_TYPE,
   ACCESS_CHECK_INFO_TYPE,
   INTERCEPTOR_INFO_TYPE,
   CALL_HANDLER_INFO_TYPE,
   FUNCTION_TEMPLATE_INFO_TYPE,
   OBJECT_TEMPLATE_INFO_TYPE,
   SIGNATURE_INFO_TYPE,
   TYPE_SWITCH_INFO_TYPE,
   SCRIPT_TYPE,
   CODE_CACHE_TYPE,
   POLYMORPHIC_CODE_CACHE_TYPE,
@@ skipping 1411 matching lines @@
     int number_of_fast_used_elements_;
     int number_of_fast_unused_elements_;
     int number_of_slow_used_elements_;
     int number_of_slow_unused_elements_;
   };
 
   void IncrementSpillStatistics(SpillInformation* info);
 #endif
   Object* SlowReverseLookup(Object* value);
 
-  // Getters and setters are stored in a fixed array property.
-  // These are constants for their indices.
-  static const int kGetterIndex = 0;
-  static const int kSetterIndex = 1;
-
   // 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 int MaxFastProperties();
 
   // 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
@@ skipping 5559 matching lines @@
   // Bit positions in flag.
   static const int kAllCanReadBit = 0;
   static const int kAllCanWriteBit = 1;
   static const int kProhibitsOverwritingBit = 2;
   class AttributesField: public BitField<PropertyAttributes, 3, 3> {};
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AccessorInfo);
 };
 
 
+// Support for JavaScript accessors: A pair of a getter and a setter. Each
+// accessor can either be
+//   * a pointer to a JavaScript function or proxy: a real accessor
+//   * undefined: considered an accessor by the spec, too, strangely enough
+//   * the hole: an accessor which has not been set
+//   * a pointer to a map: a transition used to ensure map sharing
+class AccessorPair: public Struct {
+ public:
+  DECL_ACCESSORS(getter, Object)
+  DECL_ACCESSORS(setter, Object)
+
+  static inline AccessorPair* cast(Object* obj);
+
+#ifdef OBJECT_PRINT
+  void AccessorPairPrint(FILE* out = stdout);
+#endif
+#ifdef DEBUG
+  void AccessorPairVerify();
+#endif
+
+  static const int kGetterOffset = HeapObject::kHeaderSize;
+  static const int kSetterOffset = kGetterOffset + kPointerSize;
+  static const int kSize = kSetterOffset + kPointerSize;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(AccessorPair);
+};
+
+
 class AccessCheckInfo: public Struct {
  public:
   DECL_ACCESSORS(named_callback, Object)
   DECL_ACCESSORS(indexed_callback, Object)
   DECL_ACCESSORS(data, Object)
 
   static inline AccessCheckInfo* cast(Object* obj);
 
 #ifdef OBJECT_PRINT
   inline void AccessCheckInfoPrint() {
@@ skipping 474 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_