1 /* 2 * Copyright (c) 1997, 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_RUNTIME_SAFEPOINTVERIFIERS_HPP 26 #define SHARE_VM_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 NoSafepointVerifier(bool activated=true,bool verifygc=true)89 NoSafepointVerifier(bool activated = true, bool verifygc = true ) : 90 NoGCVerifier(verifygc), 91 _activated(activated) { 92 _thread = Thread::current(); 93 if (_activated) { 94 _thread->_allow_allocation_count++; 95 _thread->_allow_safepoint_count++; 96 } 97 } 98 ~NoSafepointVerifier()99 ~NoSafepointVerifier() { 100 if (_activated) { 101 _thread->_allow_allocation_count--; 102 _thread->_allow_safepoint_count--; 103 } 104 } 105 #else 106 NoSafepointVerifier(bool activated = true, bool verifygc = true) : NoGCVerifier(verifygc){} 107 ~NoSafepointVerifier() {} 108 #endif 109 }; 110 111 // A PauseNoSafepointVerifier is used to temporarily pause the 112 // behavior of a NoSafepointVerifier object. If we are not in debug 113 // mode then there is nothing to do. If the NoSafepointVerifier 114 // object has an _activated value of false, then there is nothing to 115 // do for safepoint and allocation checking, but there may still be 116 // something to do for the underlying NoGCVerifier object. 117 118 class PauseNoSafepointVerifier : public PauseNoGCVerifier { 119 private: 120 NoSafepointVerifier * _nsv; 121 122 public: 123 #ifdef ASSERT PauseNoSafepointVerifier(NoSafepointVerifier * nsv)124 PauseNoSafepointVerifier(NoSafepointVerifier * nsv) 125 : PauseNoGCVerifier(nsv) { 126 127 _nsv = nsv; 128 if (_nsv->_activated) { 129 _nsv->_thread->_allow_allocation_count--; 130 _nsv->_thread->_allow_safepoint_count--; 131 } 132 } 133 ~PauseNoSafepointVerifier()134 ~PauseNoSafepointVerifier() { 135 if (_nsv->_activated) { 136 _nsv->_thread->_allow_allocation_count++; 137 _nsv->_thread->_allow_safepoint_count++; 138 } 139 } 140 #else 141 PauseNoSafepointVerifier(NoSafepointVerifier * nsv) 142 : PauseNoGCVerifier(nsv) {} 143 ~PauseNoSafepointVerifier() {} 144 #endif 145 }; 146 147 // A NoAllocVerifier object can be placed in methods where one assumes that 148 // no allocation will occur. The destructor will verify this property 149 // unless the constructor is called with argument false (not activated). 150 // 151 // The check will only be done in debug mode and if activated. 152 // Note: this only makes sense at safepoints (otherwise, other threads may 153 // allocate concurrently.) 154 155 class NoAllocVerifier : public StackObj { 156 private: 157 bool _activated; 158 159 public: 160 #ifdef ASSERT NoAllocVerifier(bool activated=true)161 NoAllocVerifier(bool activated = true) { 162 _activated = activated; 163 if (_activated) Thread::current()->_allow_allocation_count++; 164 } 165 ~NoAllocVerifier()166 ~NoAllocVerifier() { 167 if (_activated) Thread::current()->_allow_allocation_count--; 168 } 169 #else 170 NoAllocVerifier(bool activated = true) {} 171 ~NoAllocVerifier() {} 172 #endif 173 }; 174 175 #endif // SHARE_VM_RUNTIME_SAFEPOINTVERIFIERS_HPP 176