1 /*
   2  * Copyright (c) 2014, 2015, Red Hat, Inc. and/or its affiliates.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #include "gc/shenandoah/shenandoahRuntime.hpp"
  25 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
  26 #include "runtime/interfaceSupport.hpp"
  27 #include "oops/oop.inline.hpp"
  28 
  29 JRT_LEAF(bool, ShenandoahRuntime::compare_and_swap_object(HeapWord* addr, oopDesc* newval, oopDesc* old))
  30   bool success;
  31   oop expected;
  32   do {
  33     expected = old;
  34     old = oopDesc::atomic_compare_exchange_oop(newval, addr, expected, true);
  35     success  = (old == expected);
  36   } while ((! success) && ShenandoahBarrierSet::resolve_oop_static(old) == ShenandoahBarrierSet::resolve_oop_static(expected));
  37 
  38   return success;
  39 JRT_END