Fix redefining of attributes on aliased arguments.

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 422 matching lines @@
   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)      \
-  V(TYPE_FEEDBACK_INFO, TypeFeedbackInfo, type_feedback_info)
+  V(TYPE_FEEDBACK_INFO, TypeFeedbackInfo, type_feedback_info)                  \
+  V(ALIASED_ARGUMENTS_ENTRY, AliasedArgumentsEntry, aliased_arguments_entry)
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 #define STRUCT_LIST_DEBUGGER(V)                                                \
   V(DEBUG_INFO, DebugInfo, debug_info)                                         \
   V(BREAK_POINT_INFO, BreakPointInfo, break_point_info)
 #else
 #define STRUCT_LIST_DEBUGGER(V)
 #endif
 
 #define STRUCT_LIST(V)                                                         \
@@ skipping 135 matching lines @@
   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,
   TYPE_FEEDBACK_INFO_TYPE,
+  ALIASED_ARGUMENTS_ENTRY_TYPE,
   // The following two instance types are only used when ENABLE_DEBUGGER_SUPPORT
   // is defined. However as include/v8.h contain some of the instance type
   // constants always having them avoids them getting different numbers
   // depending on whether ENABLE_DEBUGGER_SUPPORT is defined or not.
   DEBUG_INFO_TYPE,
   BREAK_POINT_INFO_TYPE,
 
   FIXED_ARRAY_TYPE,
   SHARED_FUNCTION_INFO_TYPE,
 
@@ skipping 5819 matching lines @@
       kIcTotalCountOffset + kPointerSize;
   static const int kTypeFeedbackCellsOffset =
       kIcWithTypeinfoCountOffset + kPointerSize;
   static const int kSize = kTypeFeedbackCellsOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(TypeFeedbackInfo);
 };
 
 
+// Representation of a slow alias as part of a non-strict arguments objects.
+// For fast aliases (if HasNonStrictArgumentsElements()):
+// - the parameter map contains an index into the context
+// - all attributes of the element have default values
+// For slow aliases (if HasDictionaryArgumentsElements()):
+// - the parameter map contains no fast alias mapping (i.e. the hole)
+// - this struct (in the slow backing store) contains an index into the context
+// - all attributes are available as part if the property details
+class AliasedArgumentsEntry: public Struct {
+ public:
+  inline int aliased_context_slot();
+  inline void set_aliased_context_slot(int count);
+
+  static inline AliasedArgumentsEntry* cast(Object* obj);
+
+#ifdef OBJECT_PRINT
+  inline void AliasedArgumentsEntryPrint() {
+    AliasedArgumentsEntryPrint(stdout);
+  }
+  void AliasedArgumentsEntryPrint(FILE* out);
+#endif
+#ifdef DEBUG
+  void AliasedArgumentsEntryVerify();
+#endif
+
+  static const int kAliasedContextSlot = HeapObject::kHeaderSize;
+  static const int kSize = kAliasedContextSlot + kPointerSize;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(AliasedArgumentsEntry);
+};
+
+
 enum AllowNullsFlag {ALLOW_NULLS, DISALLOW_NULLS};
 enum RobustnessFlag {ROBUST_STRING_TRAVERSAL, FAST_STRING_TRAVERSAL};
 
 
 class StringHasher {
  public:
   explicit inline StringHasher(int length, uint32_t seed);
 
   // Returns true if the hash of this string can be computed without
   // looking at the contents.
@@ skipping 1934 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_