1 /*
   2  * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_JFR_LEAKPROFILER_UTILITIES_UNIFIEDOOP_HPP
  26 #define SHARE_VM_JFR_LEAKPROFILER_UTILITIES_UNIFIEDOOP_HPP
  27 
  28 #include "oops/oop.inline.hpp"
  29 
  30 class UnifiedOop : public AllStatic {
  31  public:
  32   static const bool is_narrow(const oop* ref) {
  33     assert(ref != NULL, "invariant");
  34     return 1 == (((u8)ref) & 1);
  35   }
  36 
  37   static const oop* decode(const oop* ref) {
  38     assert(ref != NULL, "invariant");
  39     return is_narrow(ref) ? (const oop*)(((u8)ref) & ~1) : ref;
  40   }
  41 
  42   static const oop* encode(narrowOop* ref) {
  43     assert(ref != NULL, "invariant");
  44     return (const oop*)((u8)ref | 1);
  45   }
  46 
  47   static oop dereference(const oop* ref) {
  48     assert(ref != NULL, "invariant");
  49     return is_narrow(ref) ?
  50       oopDesc::load_decode_heap_oop((narrowOop*)decode(ref)) :
  51       oopDesc::load_decode_heap_oop(const_cast<oop*>(ref));
  52   }
  53 };
  54 
  55 #endif // SHARE_VM_JFR_LEAKPROFILER_UTILITIES_UNIFIEDOOP_HPP