--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zRelocationSet.hpp	2018-06-06 00:42:19.176792942 +0200
@@ -0,0 +1,73 @@
+/*
+ * 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.
+ */
+
+#ifndef SHARE_GC_Z_ZRELOCATIONSET_HPP
+#define SHARE_GC_Z_ZRELOCATIONSET_HPP
+
+#include "memory/allocation.hpp"
+
+class ZPage;
+
+class ZRelocationSet {
+  template <bool> friend class ZRelocationSetIteratorImpl;
+
+private:
+  ZPage** _pages;
+  size_t  _npages;
+
+public:
+  ZRelocationSet();
+
+  void populate(const ZPage* const* group0, size_t ngroup0,
+                const ZPage* const* group1, size_t ngroup1);
+};
+
+template <bool parallel>
+class ZRelocationSetIteratorImpl : public StackObj {
+private:
+  ZRelocationSet* const _relocation_set;
+  size_t                _next;
+
+public:
+  ZRelocationSetIteratorImpl(ZRelocationSet* relocation_set);
+
+  bool next(ZPage** page);
+};
+
+// Iterator types
+#define ZRELOCATIONSET_SERIAL      false
+#define ZRELOCATIONSET_PARALLEL    true
+
+class ZRelocationSetIterator : public ZRelocationSetIteratorImpl<ZRELOCATIONSET_SERIAL> {
+public:
+  ZRelocationSetIterator(ZRelocationSet* relocation_set) :
+      ZRelocationSetIteratorImpl<ZRELOCATIONSET_SERIAL>(relocation_set) {}
+};
+
+class ZRelocationSetParallelIterator : public ZRelocationSetIteratorImpl<ZRELOCATIONSET_PARALLEL> {
+public:
+  ZRelocationSetParallelIterator(ZRelocationSet* relocation_set) :
+      ZRelocationSetIteratorImpl<ZRELOCATIONSET_PARALLEL>(relocation_set) {}
+};
+
+#endif // SHARE_GC_Z_ZRELOCATIONSET_HPP