1 /* 2 * Copyright (c) 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_CODE_NMETHOD_BARRIER_HPP 26 #define SHARE_CODE_NMETHOD_BARRIER_HPP 27 28 #include "memory/allocation.hpp" 29 30 31 class nmethodBarrierState { 32 struct CounterStruct { 33 int _epoch; 34 int _lock; 35 }; 36 union CounterUnion { 37 uint64_t _value; 38 CounterStruct _counters; 39 }; 40 private: 41 volatile uint64_t _state; 42 public: 43 nmethodBarrierState() : _state(0) {} 44 45 bool is_safe() const; 46 47 bool enter(); 48 void leave(); 49 void wait(); 50 }; 51 52 class nmethodBarrier: StackObj { 53 private: 54 bool _is_deoptimized; 55 nmethod* _nm; 56 address* _return_address_ptr; 57 public: 58 nmethodBarrier(nmethod* nm); 59 nmethodBarrier(nmethod* nm, address* return_address_ptr); 60 61 bool is_deoptimized() const { return _is_deoptimized; } 62 void deoptimize(); 63 void disarm(); 64 65 static int enter(address* return_address_ptr); 66 static void initialize(nmethod* nm); 67 static int disarmed_value(); 68 static bool is_armed(nmethod* nm); 69 static void disarm_barrier(nmethod* nm); 70 }; 71 72 #endif // SHARE_CODE_NMETHOD_BARRIER_HPP