diff -r 1c21c60f51bf -r 6a0c42c40cd1 src/hotspot/share/runtime/objectMonitor.inline.hpp
--- a/src/hotspot/share/runtime/objectMonitor.inline.hpp	Mon Oct 16 20:22:41 2017 +0000
+++ b/src/hotspot/share/runtime/objectMonitor.inline.hpp	Mon Oct 16 22:36:06 2017 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2017, 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
@@ -36,6 +36,11 @@
   return _header;
 }
 
+inline volatile markOop* ObjectMonitor::header_addr() {
+  assert((intptr_t)this == (intptr_t)&_header, "sync code expects this");
+  return &_header;
+}
+
 inline void ObjectMonitor::set_header(markOop hdr) {
   _header = hdr;
 }