--- old/src/share/vm/oops/klass.inline.hpp	2013-08-15 09:53:43.684975000 -0400
+++ new/src/share/vm/oops/klass.inline.hpp	2013-08-15 09:53:42.523096000 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,7 @@
 #ifndef SHARE_VM_OOPS_KLASS_INLINE_HPP
 #define SHARE_VM_OOPS_KLASS_INLINE_HPP
 
+#include "memory/universe.hpp"
 #include "oops/klass.hpp"
 #include "oops/markOop.hpp"
 
@@ -33,4 +34,41 @@
   _prototype_header = header;
 }
 
+inline bool Klass::is_null(Klass* obj)  { return obj == NULL; }
+inline bool Klass::is_null(narrowKlass obj) { return obj == 0; }
+
+// Encoding and decoding for klass field.
+
+inline bool check_klass_alignment(Klass* obj) {
+  return (intptr_t)obj % KlassAlignmentInBytes == 0;
+}
+
+inline narrowKlass Klass::encode_klass_not_null(Klass* v) {
+  assert(!is_null(v), "klass value can never be zero");
+  assert(check_klass_alignment(v), "Address not aligned");
+  int    shift = Universe::narrow_klass_shift();
+  uint64_t pd = (uint64_t)(pointer_delta((void*)v, Universe::narrow_klass_base(), 1));
+  assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");
+  uint64_t result = pd >> shift;
+  assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");
+  assert(decode_klass(result) == v, "reversibility");
+  return (narrowKlass)result;
+}
+
+inline narrowKlass Klass::encode_klass(Klass* v) {
+  return is_null(v) ? (narrowKlass)0 : encode_klass_not_null(v);
+}
+
+inline Klass* Klass::decode_klass_not_null(narrowKlass v) {
+  assert(!is_null(v), "narrow klass value can never be zero");
+  int    shift = Universe::narrow_klass_shift();
+  Klass* result = (Klass*)(void*)((uintptr_t)Universe::narrow_klass_base() + ((uintptr_t)v << shift));
+  assert(check_klass_alignment(result), err_msg("address not aligned: " PTR_FORMAT, (void*) result));
+  return result;
+}
+
+inline Klass* Klass::decode_klass(narrowKlass v) {
+  return is_null(v) ? (Klass*)NULL : decode_klass_not_null(v);
+}
+
 #endif // SHARE_VM_OOPS_KLASS_INLINE_HPP