1 /* Copyright (C) 2016 The Android Open Source Project
2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3  *
4  * This file implements interfaces from the file jvmti.h. This implementation
5  * is licensed under the same terms as the file jvmti.h.  The
6  * copyright and license information for the file jvmti.h follows.
7  *
8  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
9  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
10  *
11  * This code is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License version 2 only, as
13  * published by the Free Software Foundation.  Oracle designates this
14  * particular file as subject to the "Classpath" exception as provided
15  * by Oracle in the LICENSE file that accompanied this code.
16  *
17  * This code is distributed in the hope that it will be useful, but WITHOUT
18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
20  * version 2 for more details (a copy is included in the LICENSE file that
21  * accompanied this code).
22  *
23  * You should have received a copy of the GNU General Public License version
24  * 2 along with this work; if not, write to the Free Software Foundation,
25  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
26  *
27  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
28  * or visit www.oracle.com if you need additional information or have any
29  * questions.
30  */
31 
32 #ifndef ART_OPENJDKJVMTI_OBJECT_TAGGING_H_
33 #define ART_OPENJDKJVMTI_OBJECT_TAGGING_H_
34 
35 #include <unordered_map>
36 
37 #include "base/globals.h"
38 #include "base/mutex.h"
39 #include "jvmti.h"
40 #include "jvmti_weak_table.h"
41 #include "mirror/object.h"
42 
43 namespace openjdkjvmti {
44 
45 struct ArtJvmTiEnv;
46 class EventHandler;
47 
48 class ObjectTagTable final : public JvmtiWeakTable<jlong> {
49  public:
ObjectTagTable(EventHandler * event_handler,ArtJvmTiEnv * env)50   ObjectTagTable(EventHandler* event_handler, ArtJvmTiEnv* env)
51       : lock_("Object tag table lock", art::LockLevel::kGenericBottomLock),
52         event_handler_(event_handler),
53         jvmti_env_(env) {}
54 
55   // Denotes that weak-refs are visible on all threads. Used by semi-space.
56   void Allow() override
57       REQUIRES_SHARED(art::Locks::mutator_lock_)
58       REQUIRES(!allow_disallow_lock_);
59   // Used by cms and the checkpoint system.
60   void Broadcast(bool broadcast_for_checkpoint) override
61       REQUIRES_SHARED(art::Locks::mutator_lock_)
62       REQUIRES(!allow_disallow_lock_);
63 
64   bool Set(art::ObjPtr<art::mirror::Object> obj, jlong tag) override
65       REQUIRES_SHARED(art::Locks::mutator_lock_)
66       REQUIRES(!allow_disallow_lock_);
67   bool SetLocked(art::ObjPtr<art::mirror::Object> obj, jlong tag) override
68       REQUIRES_SHARED(art::Locks::mutator_lock_)
69       REQUIRES(allow_disallow_lock_);
70 
GetTagOrZero(art::ObjPtr<art::mirror::Object> obj)71   jlong GetTagOrZero(art::ObjPtr<art::mirror::Object> obj)
72       REQUIRES_SHARED(art::Locks::mutator_lock_)
73       REQUIRES(!allow_disallow_lock_) {
74     jlong tmp = 0;
75     GetTag(obj, &tmp);
76     return tmp;
77   }
GetTagOrZeroLocked(art::ObjPtr<art::mirror::Object> obj)78   jlong GetTagOrZeroLocked(art::ObjPtr<art::mirror::Object> obj)
79       REQUIRES_SHARED(art::Locks::mutator_lock_)
80       REQUIRES(allow_disallow_lock_) {
81     jlong tmp = 0;
82     GetTagLocked(obj, &tmp);
83     return tmp;
84   }
85 
86  protected:
87   bool DoesHandleNullOnSweep() override;
88   void HandleNullSweep(jlong tag) override;
89 
90  private:
91   void SendDelayedFreeEvents()
92       REQUIRES_SHARED(art::Locks::mutator_lock_)
93       REQUIRES(!allow_disallow_lock_);
94 
95   void SendSingleFreeEvent(jlong tag)
96       REQUIRES_SHARED(art::Locks::mutator_lock_)
97       REQUIRES(!allow_disallow_lock_, !lock_);
98 
99   art::Mutex lock_ BOTTOM_MUTEX_ACQUIRED_AFTER;
100   std::vector<jlong> null_tags_ GUARDED_BY(lock_);
101   EventHandler* event_handler_;
102   ArtJvmTiEnv* jvmti_env_;
103 };
104 
105 }  // namespace openjdkjvmti
106 
107 #endif  // ART_OPENJDKJVMTI_OBJECT_TAGGING_H_
108