1 /* 2 * Copyright (c) 1997, 2019, 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_RUNTIME_SAFEPOINTVERIFIERS_HPP 26 #define SHARE_RUNTIME_SAFEPOINTVERIFIERS_HPP 27 28 #include "memory/allocation.hpp" 29 #include "runtime/thread.hpp" 30 31 // A NoGCVerifier object can be placed in methods where one assumes that 32 // no garbage collection will occur. The destructor will verify this property 33 // unless the constructor is called with argument false (not verifygc). 34 // 35 // The check will only be done in debug mode and if verifygc true. 36 37 class NoGCVerifier: public StackObj { 38 friend class PauseNoGCVerifier; 39 40 protected: 41 bool _verifygc; 42 unsigned int _old_invocations; 43 44 public: 45 #ifdef ASSERT 46 NoGCVerifier(bool verifygc = true); 47 ~NoGCVerifier(); 48 #else 49 NoGCVerifier(bool verifygc = true) {} 50 ~NoGCVerifier() {} 51 #endif 52 }; 53 54 // A PauseNoGCVerifier is used to temporarily pause the behavior 55 // of a NoGCVerifier object. If we are not in debug mode or if the 56 // NoGCVerifier object has a _verifygc value of false, then there 57 // is nothing to do. 58 59 class PauseNoGCVerifier: public StackObj { 60 private: 61 NoGCVerifier * _ngcv; 62 63 public: 64 #ifdef ASSERT 65 PauseNoGCVerifier(NoGCVerifier * ngcv); 66 ~PauseNoGCVerifier(); 67 #else 68 PauseNoGCVerifier(NoGCVerifier * ngcv) {} 69 ~PauseNoGCVerifier() {} 70 #endif 71 }; 72 73 74 // A NoSafepointVerifier object will throw an assertion failure if 75 // the current thread passes a possible safepoint while this object is 76 // instantiated. A safepoint, will either be: an oop allocation, blocking 77 // on a Mutex or JavaLock, or executing a VM operation. 78 // 79 // If StrictSafepointChecks is turned off, it degrades into a NoGCVerifier 80 // 81 class NoSafepointVerifier : public NoGCVerifier { 82 friend class PauseNoSafepointVerifier; 83 84 private: 85 bool _activated; 86 Thread *_thread; 87 public: 88 #ifdef ASSERT 89 NoSafepointVerifier(bool activated = true, bool verifygc = true ) : 90 NoGCVerifier(verifygc), 91 _activated(activated) { 92 _thread = Thread::current(); 93 if (_activated) { 94 _thread->_allow_safepoint_count++; 95 } 96 } 97 98 ~NoSafepointVerifier() { 99 if (_activated) { 100 _thread->_allow_safepoint_count--; 101 } 102 } 103 #else 104 NoSafepointVerifier(bool activated = true, bool verifygc = true) : NoGCVerifier(verifygc){} 105 ~NoSafepointVerifier() {} 106 #endif 107 }; 108 109 // A PauseNoSafepointVerifier is used to temporarily pause the 110 // behavior of a NoSafepointVerifier object. If we are not in debug 111 // mode then there is nothing to do. If the NoSafepointVerifier 112 // object has an _activated value of false, then there is nothing to 113 // do for safepoint and allocation checking, but there may still be 114 // something to do for the underlying NoGCVerifier object. 115 116 class PauseNoSafepointVerifier : public PauseNoGCVerifier { 117 private: 118 NoSafepointVerifier * _nsv; 119 120 public: 121 #ifdef ASSERT 122 PauseNoSafepointVerifier(NoSafepointVerifier * nsv) 123 : PauseNoGCVerifier(nsv) { 124 125 _nsv = nsv; 126 if (_nsv->_activated) { 127 _nsv->_thread->_allow_safepoint_count--; 128 } 129 } 130 131 ~PauseNoSafepointVerifier() { 132 if (_nsv->_activated) { 133 _nsv->_thread->_allow_safepoint_count++; 134 } 135 } 136 #else 137 PauseNoSafepointVerifier(NoSafepointVerifier * nsv) 138 : PauseNoGCVerifier(nsv) {} 139 ~PauseNoSafepointVerifier() {} 140 #endif 141 }; 142 143 #endif // SHARE_RUNTIME_SAFEPOINTVERIFIERS_HPP