--- /dev/null	2015-10-26 11:54:12.816915698 -0400
+++ new/src/share/vm/classfile/backtrace.hpp	2015-10-30 18:24:03.009743083 -0400
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2015, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_CLASSFILE_BACKTRACE_HPP
+#define SHARE_VM_CLASSFILE_BACKTRACE_HPP
+
+#include "memory/allocation.hpp"
+#include "memory/iterator.hpp"
+#include "oops/oop.inline.hpp"
+
+// Backtrace management - Method* on backtraces need to be preserved for
+// RedefineClasses, so we keep a list and mark them as on_stack so that the Method*
+// doesn't get deallocatd.
+// This list is managed as a weak root, but doesn't use jweak because
+// the cost of creating these objects is performance critical.
+
+class Backtrace : public CHeapObj<mtClass> {
+  oop        _throwable;
+  Backtrace* _next;
+
+ public:
+  Backtrace(oop throwable) : _throwable(throwable), _next(NULL) {}
+  oop throwable()              { return _throwable; }
+  Backtrace* next() const      { return _next; }
+  void set_next(Backtrace* bt) { _next = bt; }
+  // GC support
+  void oops_do(OopClosure* f);
+};
+
+class BacktraceList : public AllStatic {
+  // List of backtraces to mark Method pointers.
+  static Backtrace* _backtraces_head;
+  static volatile int _bt_count;
+
+ public:
+  static void mark_on_stack();
+  static void unlink(BoolObjectClosure* is_alive);
+  static void add(oop throwable);
+  static void oops_do(OopClosure* f);
+};
+
+#endif // SHARE_VM_CLASSFILE_BACKTRACE_HPP