1 /*
2 * Copyright (c) 2000, 2008, 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 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
26 // enumerate ref fields that have been modified (since the last
27 // enumeration), using a card table.
28
29 class OopClosure;
30 class Generation;
31
32 class ModRefBarrierSet: public BarrierSet {
33 public:
34
35 ModRefBarrierSet() { _kind = BarrierSet::ModRef; }
36
37 bool is_a(BarrierSet::Name bsn) {
38 return bsn == BarrierSet::ModRef;
39 }
40
41 // Barriers only on ref writes.
42 bool has_read_ref_barrier() { return false; }
43 bool has_read_prim_barrier() { return false; }
44 bool has_write_ref_barrier() { return true; }
94
95 // Causes all refs in "mr" to be assumed to be modified. If "whole_heap"
96 // is true, the caller asserts that the entire heap is being invalidated,
97 // which may admit an optimized implementation for some barriers.
98 virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0;
99
100 // The caller guarantees that "mr" contains no references. (Perhaps it's
101 // objects have been moved elsewhere.)
102 virtual void clear(MemRegion mr) = 0;
103
104 // Pass along the argument to the superclass.
105 ModRefBarrierSet(int max_covered_regions) :
106 BarrierSet(max_covered_regions) {}
107
108 #ifndef PRODUCT
109 // Verifies that the given region contains no modified references.
110 virtual void verify_clean_region(MemRegion mr) = 0;
111 #endif
112
113 };
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1 /*
2 * Copyright (c) 2000, 2010, 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_MEMORY_MODREFBARRIERSET_HPP
26 #define SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
27
28 #include "memory/barrierSet.hpp"
29
30 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
31 // enumerate ref fields that have been modified (since the last
32 // enumeration), using a card table.
33
34 class OopClosure;
35 class Generation;
36
37 class ModRefBarrierSet: public BarrierSet {
38 public:
39
40 ModRefBarrierSet() { _kind = BarrierSet::ModRef; }
41
42 bool is_a(BarrierSet::Name bsn) {
43 return bsn == BarrierSet::ModRef;
44 }
45
46 // Barriers only on ref writes.
47 bool has_read_ref_barrier() { return false; }
48 bool has_read_prim_barrier() { return false; }
49 bool has_write_ref_barrier() { return true; }
99
100 // Causes all refs in "mr" to be assumed to be modified. If "whole_heap"
101 // is true, the caller asserts that the entire heap is being invalidated,
102 // which may admit an optimized implementation for some barriers.
103 virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0;
104
105 // The caller guarantees that "mr" contains no references. (Perhaps it's
106 // objects have been moved elsewhere.)
107 virtual void clear(MemRegion mr) = 0;
108
109 // Pass along the argument to the superclass.
110 ModRefBarrierSet(int max_covered_regions) :
111 BarrierSet(max_covered_regions) {}
112
113 #ifndef PRODUCT
114 // Verifies that the given region contains no modified references.
115 virtual void verify_clean_region(MemRegion mr) = 0;
116 #endif
117
118 };
119
120 #endif // SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
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