--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/gtest/gc/shared/test_preservedMarks.cpp	Tue Nov 14 11:33:23 2017 +0100
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 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
+ * 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 "unittest.hpp"
+
+class ScopedDisabledBiasedLocking {
+  bool _orig;
+public:
+  ScopedDisabledBiasedLocking() : _orig(UseBiasedLocking) { UseBiasedLocking = false; }
+  ~ScopedDisabledBiasedLocking() { UseBiasedLocking = _orig; }
+};
+
+// Class to create a "fake" oop with a mark that will
+// return true for calls to must_be_preserved().
+class FakeOop {
+  oopDesc _oop;
+
+public:
+  FakeOop() : _oop() { _oop.set_mark(originalMark()); }
+
+  oop get_oop() { return &_oop; }
+  markOop mark() { return _oop.mark(); }
+  void set_mark(markOop m) { _oop.set_mark(m); }
+  void forward_to(oop obj) {
+    markOop m = markOopDesc::encode_pointer_as_mark(obj);
+    _oop.set_mark(m);
+  }
+
+  static markOop originalMark() { return markOop(markOopDesc::lock_mask_in_place); }
+  static markOop changedMark()  { return markOop(0x4711); }
+};
+
+TEST_VM(PreservedMarks, iterate_and_restore) {
+  // Need to disable biased locking to easily
+  // create oops that "must_be_preseved"
+  ScopedDisabledBiasedLocking dbl;
+
+  PreservedMarks pm;
+  FakeOop o1;
+  FakeOop o2;
+  FakeOop o3;
+  FakeOop o4;
+
+  // Make sure initial marks are correct.
+  ASSERT_EQ(o1.mark(), FakeOop::originalMark());
+  ASSERT_EQ(o2.mark(), FakeOop::originalMark());
+  ASSERT_EQ(o3.mark(), FakeOop::originalMark());
+  ASSERT_EQ(o4.mark(), FakeOop::originalMark());
+
+  // Change the marks and verify change.
+  o1.set_mark(FakeOop::changedMark());
+  o2.set_mark(FakeOop::changedMark());
+  ASSERT_EQ(o1.mark(), FakeOop::changedMark());
+  ASSERT_EQ(o2.mark(), FakeOop::changedMark());
+
+  // Push o1 and o2 to have their marks preserved.
+  pm.push(o1.get_oop(), o1.mark());
+  pm.push(o2.get_oop(), o2.mark());
+
+  // Fake a move from o1->o3 and o2->o4.
+  o1.forward_to(o3.get_oop());
+  o2.forward_to(o4.get_oop());
+  ASSERT_EQ(o1.get_oop()->forwardee(), o3.get_oop());
+  ASSERT_EQ(o2.get_oop()->forwardee(), o4.get_oop());
+  // Adjust will update the PreservedMarks stack to
+  // make sure the mark is updated at the new location.
+  pm.adjust_during_full_gc();
+
+  // Restore all preserved and verify that the changed
+  // mark is now present at o3 and o4.
+  pm.restore();
+  ASSERT_EQ(o3.mark(), FakeOop::changedMark());
+  ASSERT_EQ(o4.mark(), FakeOop::changedMark());
+}