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comparison src/share/vm/memory/modRefBarrierSet.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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-1:000000000000 0:a61af66fc99e
1 /*
2 * Copyright 2000-2002 Sun Microsystems, 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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 // Barriers only on ref writes.
35 bool has_read_ref_barrier() { return false; }
36 bool has_read_prim_barrier() { return false; }
37 bool has_write_ref_barrier() { return true; }
38 bool has_write_prim_barrier() { return false; }
39
40 bool read_ref_needs_barrier(oop* field) { return false; }
41 bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
42 virtual bool write_ref_needs_barrier(oop* field, oop new_val) = 0;
43 bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
44 juint val1, juint val2) { return false; }
45
46 void write_prim_field(oop obj, size_t offset, size_t bytes,
47 juint val1, juint val2) {}
48
49 void read_ref_field(oop* field) {}
50 void read_prim_field(HeapWord* field, size_t bytes) {}
51 protected:
52 virtual void write_ref_field_work(oop* field, oop new_val) = 0;
53 public:
54 void write_prim_field(HeapWord* field, size_t bytes,
55 juint val1, juint val2) {}
56
57 bool has_read_ref_array_opt() { return false; }
58 bool has_read_prim_array_opt() { return false; }
59 bool has_write_prim_array_opt() { return false; }
60
61 bool has_read_region_opt() { return false; }
62
63
64 // These operations should assert false unless the correponding operation
65 // above returns true.
66 void read_ref_array(MemRegion mr) {
67 assert(false, "can't call");
68 }
69 void read_prim_array(MemRegion mr) {
70 assert(false, "can't call");
71 }
72 void write_prim_array(MemRegion mr) {
73 assert(false, "can't call");
74 }
75 void read_region(MemRegion mr) {
76 assert(false, "can't call");
77 }
78
79 // Invoke "cl->do_oop" on (the address of) every possibly-modifed
80 // reference field in objects in "sp". If "clear" is "true", the oops
81 // are no longer considered possibly modified after application of the
82 // closure. If' "before_save_marks" is true, oops in objects allocated
83 // after the last call to "save_marks" on "sp" will not be considered.
84 virtual void mod_oop_in_space_iterate(Space* sp, OopClosure* cl,
85 bool clear = false,
86 bool before_save_marks = false) = 0;
87
88 // Causes all refs in "mr" to be assumed to be modified.
89 virtual void invalidate(MemRegion mr) = 0;
90
91 // The caller guarantees that "mr" contains no references. (Perhaps it's
92 // objects have been moved elsewhere.)
93 virtual void clear(MemRegion mr) = 0;
94
95 // Pass along the argument to the superclass.
96 ModRefBarrierSet(int max_covered_regions) :
97 BarrierSet(max_covered_regions) {}
98
99 #ifndef PRODUCT
100 // Verifies that the given region contains no modified references.
101 virtual void verify_clean_region(MemRegion mr) = 0;
102 #endif
103
104 };