Use mutable heapnumbers to store doubles in fields.

src/builtins.cc

 // 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 1490 matching lines @@
 }
 
 static void Generate_KeyedLoadIC_IndexedInterceptor(MacroAssembler* masm) {
   KeyedLoadIC::GenerateIndexedInterceptor(masm);
 }
 
 static void Generate_KeyedLoadIC_NonStrictArguments(MacroAssembler* masm) {
   KeyedLoadIC::GenerateNonStrictArguments(masm);
 }
 
+static void Generate_StoreIC_Slow(MacroAssembler* masm) {
+  StoreIC::GenerateSlow(masm);
+}
+
+
 static void Generate_StoreIC_Initialize(MacroAssembler* masm) {
   StoreIC::GenerateInitialize(masm);
 }
 
 
 static void Generate_StoreIC_Initialize_Strict(MacroAssembler* masm) {
   StoreIC::GenerateInitialize(masm);
 }
 
 
@@ skipping 357 matching lines @@
   return Handle<Code>(code_address);                        \
 }
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 } }  // namespace v8::internal