1 /* 2 * Copyright (c) 2013, 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/metadataOnStackMark.hpp" 27 #include "code/codeCache.hpp" 28 #include "compiler/compileBroker.hpp" 29 #include "oops/metadata.hpp" 30 #include "prims/jvmtiImpl.hpp" 31 #include "runtime/synchronizer.hpp" 32 #include "runtime/thread.hpp" 33 #include "services/threadService.hpp" 34 #include "utilities/growableArray.hpp" 35 36 37 // Keep track of marked on-stack metadata so it can be cleared. 38 GrowableArray<Metadata*>* _marked_objects = NULL; 39 NOT_PRODUCT(bool MetadataOnStackMark::_is_active = false;) 40 41 // Walk metadata on the stack and mark it so that redefinition doesn't delete 42 // it. Class unloading also walks the previous versions and might try to 43 // delete it, so this class is used by class unloading also. 44 MetadataOnStackMark::MetadataOnStackMark() { 45 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 46 NOT_PRODUCT(_is_active = true;) 47 if (_marked_objects == NULL) { 48 _marked_objects = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(1000, true); 49 } 50 Threads::metadata_do(Metadata::mark_on_stack); 51 CodeCache::alive_nmethods_do(nmethod::mark_on_stack); 52 CompileBroker::mark_on_stack(); 53 JvmtiCurrentBreakpoints::metadata_do(Metadata::mark_on_stack); 54 ThreadService::metadata_do(Metadata::mark_on_stack); 55 } 56 57 MetadataOnStackMark::~MetadataOnStackMark() { 58 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 59 // Unmark everything that was marked. Can't do the same walk because 60 // redefine classes messes up the code cache so the set of methods 61 // might not be the same. 62 for (int i = 0; i< _marked_objects->length(); i++) { 63 _marked_objects->at(i)->set_on_stack(false); 64 } 65 _marked_objects->clear(); // reuse growable array for next time. 66 NOT_PRODUCT(_is_active = false;) 67 } 68 69 // Record which objects are marked so we can unmark the same objects. 70 void MetadataOnStackMark::record(Metadata* m) { 71 assert(_is_active, "metadata on stack marking is active"); 72 _marked_objects->push(m); 73 }