1 /*
2 * Copyright (c) 2001, 2016, 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 #ifndef SHARE_VM_GC_G1_G1BARRIERSET_HPP
26 #define SHARE_VM_GC_G1_G1BARRIERSET_HPP
27
28 #include "gc/shared/cardTableModRefBS.hpp"
29
30 class CardTable;
31 class DirtyCardQueueSet;
32 class G1CardTable;
33 class SATBMarkQueueSet;
34
35 // This barrier is specialized to use a logging barrier to support
36 // snapshot-at-the-beginning marking.
37
38 class G1BarrierSet: public CardTableModRefBS {
39 friend class VMStructs;
40 private:
41 void write_ref_nmethod_pre(nmethod* nm, ptrdiff_t offset);
42 void write_ref_nmethod_post(nmethod* nm, oop new_value);
43 static bool is_referent_field(oop base, ptrdiff_t offset);
44
45 public:
46 G1BarrierSet(CardTable* table);
47 ~G1BarrierSet() { }
48
49 static SATBMarkQueueSet& satb_mark_queue_set();
50 static DirtyCardQueueSet& dirty_card_queue_set();
51
52 // Add "pre_val" to a set of objects that may have been disconnected from the
53 // pre-marking object graph.
54 static void satb_enqueue(oop pre_val);
55 static void card_enqueue(volatile jbyte* card);
56
57 template <DecoratorSet decorators>
58 void write_ref_field_pre(void* field);
59
60 template <DecoratorSet decorators>
61 void write_ref_field_post(void* field, oop new_val);
62
63 void klass_update_barrier_set_pre(Klass* klass, oop* p);
64
65 template <class T> void write_ref_array_pre_work(T* dst, int count);
66 virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized);
67 virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized);
68
69 // NB: if you do a whole-heap invalidation, the "usual invariant" defined
70 // above no longer applies.
71 void invalidate(MemRegion mr);
72
73 virtual void write_region(MemRegion mr) { invalidate(mr); }
74
75 virtual void write_ref_array_region(MemRegion mr) { invalidate(mr); }
76
77 // This method initializes the SATB and dirty card queues before a
78 // JavaThread is added to the Java thread list. Right now, we don't
79 // have to do anything to the dirty card queue (it should have been
80 // activated when the thread was created), but we have to activate
81 // the SATB queue if the thread is created while a marking cycle is
82 // in progress. The activation / de-activation of the SATB queues at
83 // the beginning / end of a marking cycle is done during safepoints
84 // so we have to make sure this method is called outside one to be
85 // able to safely read the active field of the SATB queue set. Right
86 // now, it is called just before the thread is added to the Java
87 // thread list in the Threads::add() method. That method is holding
88 // the Threads_lock which ensures we are outside a safepoint. We
89 // cannot do the obvious and set the active field of the SATB queue
90 // when the thread is created given that, in some cases, safepoints
91 // might happen between the JavaThread constructor being called and the
92 // thread being added to the Java thread list (an example of this is
93 // when the structure for the DestroyJavaVM thread is created).
94 virtual void on_add_thread(JavaThread* thread);
95
96 virtual void on_destroy_thread(JavaThread* thread);
97
98 virtual BarrierSetCodeGen *make_code_gen();
99 virtual C1BarrierSetCodeGen* make_c1_code_gen();
100 virtual C2BarrierSetCodeGen* make_c2_code_gen();
101
102 // Runtime calls for generated code
103 static void g1_wb_pre(oopDesc* orig, JavaThread *thread);
104 static void g1_wb_post(void* card_addr, JavaThread* thread);
105
106 // Callbacks for runtime accesses.
107 template <DecoratorSet decorators>
108 class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, G1BarrierSet> {
109 typedef ModRefBarrierSet::AccessBarrier<decorators, G1BarrierSet> ModRef;
110 typedef BarrierSet::AccessBarrier<decorators> Basic;
111
112 public:
113 typedef ModRef SuperAccessBarrier;
114
115 // Needed for loads on weak references
116 static oop oop_load(void* addr);
117
118 // Needed for anonymous weak references
119 static oop oop_load_at(oop base, ptrdiff_t offset);
120
121 // Needed for stores in nmethods
122 static void oop_store_at(nmethod* base, ptrdiff_t offset, oop new_value);
123 };
124 };
125
126 template<>
127 struct BSTypeToName<G1BarrierSet> {
128 static const BarrierSet::Name value = BarrierSet::G1BarrierSet;
129 };
130
131 template<>
132 struct BSNameToType<BarrierSet::G1BarrierSet> {
133 typedef G1BarrierSet type;
134 };
135
136 #endif // SHARE_VM_GC_G1_G1BARRIERSET_HPP