/*

 * 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