--- /dev/null	2020-01-17 11:46:19.065201212 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahForwarding.hpp	2020-01-17 17:10:04.341130797 +0100
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
+ *
+ * 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_SHENANDOAH_SHENANDOAHFORWARDING_HPP
+#define SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_HPP
+
+#include "oops/oop.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class ShenandoahForwarding {
+public:
+  /* Gets forwardee from the given object.
+   */
+  static inline oop get_forwardee(oop obj);
+
+  /* Returns the raw value from forwardee slot.
+   */
+  static inline HeapWord* get_forwardee_raw(oop obj);
+
+  /* Returns the raw value from forwardee slot without any checks.
+   * Used for quick verification.
+   */
+  static inline HeapWord* get_forwardee_raw_unchecked(oop obj);
+
+  /**
+   * Returns true if the object is forwarded, false otherwise.
+   */
+  static inline bool is_forwarded(oop obj);
+
+  /* Tries to atomically update forwardee in $holder object to $update.
+   * Assumes $holder points at itself.
+   * Asserts $holder is in from-space.
+   * Asserts $update is in to-space.
+   *
+   * Returns the new object 'update' upon success, or
+   * the new forwardee that a competing thread installed.
+   */
+  static inline oop try_update_forwardee(oop obj, oop update);
+
+};
+
+#endif // SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_HPP