--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/shared/preservedMarks.cpp	Tue Feb 23 10:44:05 2016 +0100
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2016, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/shared/preservedMarks.inline.hpp"
+#include "memory/allocation.inline.hpp"
+#include "oops/oop.inline.hpp"
+
+void PreservedMarks::restore() {
+  // First, iterate over the stack and restore all marks.
+  StackIterator<OopAndMarkOop, mtGC> iter(_stack);
+  while (!iter.is_empty()) {
+    OopAndMarkOop elem = iter.next();
+    elem.set_mark();
+  }
+
+  // Second, reclaim all the stack memory
+  _stack.clear(true /* clear_cache */);
+}
+
+void RemoveForwardedPointerClosure::do_object(oop obj) {
+  if (obj->is_forwarded()) {
+    obj->init_mark();
+  }
+}
+
+void PreservedMarksSet::init(uint num) {
+  assert(_stacks == NULL && _num == 0, "do not re-initialize");
+  assert(num > 0, "pre-condition");
+  if (_in_c_heap) {
+    _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
+  } else {
+    _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
+  }
+  for (uint i = 0; i < num; i += 1) {
+    ::new (_stacks + i) PreservedMarks();
+  }
+  _num = num;
+
+  assert_empty();
+}
+
+void PreservedMarksSet::restore() {
+  for (uint i = 0; i < _num; i += 1) {
+    get(i)->restore();
+  }
+}
+
+void PreservedMarksSet::reclaim() {
+  assert_empty();
+
+  for (uint i = 0; i < _num; i += 1) {
+    _stacks[i].~Padded<PreservedMarks>();
+  }
+
+  if (_in_c_heap) {
+    FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks);
+  } else {
+    // the array was resource-allocated, so nothing to do
+  }
+  _stacks = NULL;
+  _num = 0;
+}
+
+#ifndef PRODUCT
+void PreservedMarksSet::assert_empty() {
+  assert(_stacks != NULL && _num > 0, "should have been initialized");
+  for (uint i = 0; i < _num; i += 1) {
+    assert(get(i)->is_empty(), "stack should be empty");
+  }
+}
+#endif // ndef PRODUCT