Fri, 26 Sep 2014 17:48:10 -0400
8047125: (ref) More phantom object references
Reviewed-by: mchung, dfuchs, ahgross, jmasa, brutisso, mgerdin
Contributed-by: kim.barrett@oracle.com
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
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23 */
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"
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;)
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 }
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 }
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 }