1 /*
 2  * Copyright (c) 2017, 2022, Red Hat, Inc. 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_GC_SHENANDOAH_SHENANDOAHCODEROOTS_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHCODEROOTS_HPP
27 
28 #include "code/codeCache.hpp"
29 #include "gc/shenandoah/shenandoahLock.hpp"
30 #include "gc/shenandoah/shenandoahPadding.hpp"
31 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
32 #include "memory/allStatic.hpp"
33 #include "memory/iterator.hpp"
34 #include "utilities/globalDefinitions.hpp"
35 
36 class ShenandoahHeap;
37 class ShenandoahHeapRegion;
38 class ShenandoahNMethodTable;
39 class ShenandoahNMethodTableSnapshot;
40 class WorkerThreads;
41 
42 class ShenandoahCodeRootsIterator {
43   friend class ShenandoahCodeRoots;
44 protected:
45   ShenandoahNMethodTableSnapshot* _table_snapshot;
46 
47 public:
48   ShenandoahCodeRootsIterator();
49   ~ShenandoahCodeRootsIterator();
50 
51   void possibly_parallel_nmethods_do(NMethodClosure *f);
52 };
53 
54 class ShenandoahCodeRoots : public AllStatic {
55   friend class ShenandoahHeap;
56   friend class ShenandoahCodeRootsIterator;
57 
58 public:
59   static void initialize();
60   static void register_nmethod(nmethod* nm);
61   static void unregister_nmethod(nmethod* nm);
62 
63   static ShenandoahNMethodTable* table() {
64     return _nmethod_table;
65   }
66 
67   // Concurrent nmethod unloading support
68   static void unlink(WorkerThreads* workers, bool unloading_occurred);
69   static void purge();
70   static void arm_nmethods_for_mark();
71   static void arm_nmethods_for_evac();
72   static void disarm_nmethods();
73   static int  disarmed_value()         { return _disarmed_value; }
74   static int* disarmed_value_address() { return &_disarmed_value; }
75 
76   static bool use_nmethod_barriers_for_mark();
77 
78 private:
79   static ShenandoahNMethodTable* _nmethod_table;
80   static int                     _disarmed_value;
81 };
82 
83 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCODEROOTS_HPP