/*
 * Copyright (c) 2018, 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
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 */

#ifndef SHARE_CODE_NMETHOD_BARRIER_HPP
#define SHARE_CODE_NMETHOD_BARRIER_HPP

#include "memory/allocation.hpp"

class nmethodBarrierState {
  struct CounterStruct {
    int _epoch;
    int _lock;
  };
  union CounterUnion {
    uint64_t _value;
    CounterStruct _counters;
  };
private:
  volatile uint64_t _state;
public:
  nmethodBarrierState() : _state(0) {}

  bool is_safe() const;

  bool enter();
  void leave();
  void wait();
};

class nmethodBarrier: StackObj {
private:
  bool _is_deoptimized;
  nmethod* _nm;
  address* _return_address_ptr;
public:
  nmethodBarrier(nmethod* nm);
  nmethodBarrier(nmethod* nm, address* return_address_ptr);

  bool is_deoptimized() const { return _is_deoptimized; }
  void deoptimize();
  void disarm();

  static int enter(address* return_address_ptr);
  static int disarmed_value();
  static bool is_armed(nmethod* nm);
  static void disarm_barrier(nmethod* nm);
};

#endif // SHARE_CODE_NMETHOD_BARRIER_HPP