Add inline caches for loading non-existing properties.

src/globals.h

 // Copyright 2006-2009 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 410 matching lines @@
 enum PropertyType {
   NORMAL              = 0,  // only in slow mode
   FIELD               = 1,  // only in fast mode
   CONSTANT_FUNCTION   = 2,  // only in fast mode
   CALLBACKS           = 3,
   INTERCEPTOR         = 4,  // only in lookup results, not in descriptors.
   MAP_TRANSITION      = 5,  // only in fast mode
   CONSTANT_TRANSITION = 6,  // only in fast mode
   NULL_DESCRIPTOR     = 7,  // only in fast mode
   // All properties before MAP_TRANSITION are real.
-  FIRST_PHANTOM_PROPERTY_TYPE = MAP_TRANSITION
+  FIRST_PHANTOM_PROPERTY_TYPE = MAP_TRANSITION,
+  // There are no IC stubs for NULL_DESCRIPTORS. Therefore,
+  // NULL_DESCRIPTOR can be used as the type flag for IC stubs for
+  // non-existing properties.
+  NON_EXISTING  = NULL_DESCRIPTOR
 };
 
 
 // Whether to remove map transitions and constant transitions from a
 // DescriptorArray.
 enum TransitionFlag {
   REMOVE_TRANSITIONS,
   KEEP_TRANSITIONS
 };
 
@@ skipping 157 matching lines @@
                   CMOV = 15,   // x86
                   RDTSC = 4,   // x86
                   CPUID = 10,  // x86
                   VFP3 = 1,    // ARM
                   ARMv7 = 2,   // ARM
                   SAHF = 0};   // x86
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBALS_H_