1 /* 2 * Copyright (c) 2015, 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 #include "precompiled.hpp" 26 #include "classfile/backtrace.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "runtime/atomic.hpp" 29 #include "runtime/jniHandles.hpp" 30 31 void Backtrace::oops_do(OopClosure* f) { 32 f->do_oop(&_throwable); 33 } 34 35 // List of backtraces to mark Method pointers for RedefineClasses. 36 Backtrace* BacktraceList::_backtraces_head = NULL; 37 volatile int BacktraceList::_bt_count = 0; 38 39 void BacktraceList::add(oop throwable) { 40 Backtrace* bt = new Backtrace(throwable); 41 Backtrace* next = _backtraces_head; 42 do { 43 bt->set_next(next); 44 Backtrace* exchanged = (Backtrace*)Atomic::cmpxchg_ptr(bt, &_backtraces_head, next); 45 if (exchanged == next) { 46 // added the backtrace to the list. 47 Atomic::inc(&_bt_count); 48 return; 49 } 50 next = exchanged; 51 } while (true); 52 } 53 54 void BacktraceList::oops_do(OopClosure* f) { 55 Backtrace* bt = _backtraces_head; 56 while (bt != NULL) { 57 bt->oops_do(f); 58 bt = bt->next(); 59 } 60 } 61 62 void BacktraceList::mark_on_stack() { 63 Backtrace* bt = _backtraces_head; 64 while (bt != NULL) { 65 assert(bt->throwable() != NULL, "shouldn't have null throwable"); 66 java_lang_Throwable::mark_on_stack(bt->throwable()); 67 bt = bt->next(); 68 } 69 } 70 71 void BacktraceList::unlink(BoolObjectClosure* is_alive) { 72 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint"); 73 Backtrace* bt = _backtraces_head; 74 Backtrace* prev = NULL; 75 while (bt != NULL) { 76 if (!is_alive->do_object_b(bt->throwable())) { 77 // delete this backtrace object 78 Backtrace* next = bt->next(); 79 // Delete bt object 80 delete bt; 81 // Remove from throwable list. 82 bt = next; 83 if (prev != NULL) { 84 prev->set_next(bt); 85 } else { 86 _backtraces_head = bt; 87 } 88 Atomic::dec(&_bt_count); 89 } else { 90 prev = bt; 91 bt = bt->next(); 92 } 93 } 94 }