1 /*
2 * Copyright (c) 2001, 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 inline OopsInGenClosure::OopsInGenClosure(Generation* gen) :
26 OopClosure(gen->ref_processor()), _orig_gen(gen), _rs(NULL) {
27 set_generation(gen);
28 }
29
30 inline void OopsInGenClosure::set_generation(Generation* gen) {
31 _gen = gen;
32 _gen_boundary = _gen->reserved().start();
33 // Barrier set for the heap, must be set after heap is initialized
34 if (_rs == NULL) {
35 GenRemSet* rs = SharedHeap::heap()->rem_set();
36 assert(rs->rs_kind() == GenRemSet::CardTable, "Wrong rem set kind");
37 _rs = (CardTableRS*)rs;
38 }
39 }
40
41 template <class T> inline void OopsInGenClosure::do_barrier(T* p) {
42 assert(generation()->is_in_reserved(p), "expected ref in generation");
43 T heap_oop = oopDesc::load_heap_oop(p);
44 assert(!oopDesc::is_null(heap_oop), "expected non-null oop");
45 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
46 // If p points to a younger generation, mark the card.
47 if ((HeapWord*)obj < _gen_boundary) {
48 _rs->inline_write_ref_field_gc(p, obj);
49 }
50 }
51
52 template <class T> inline void OopsInGenClosure::par_do_barrier(T* p) {
53 assert(generation()->is_in_reserved(p), "expected ref in generation");
54 T heap_oop = oopDesc::load_heap_oop(p);
55 assert(!oopDesc::is_null(heap_oop), "expected non-null oop");
56 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
57 // If p points to a younger generation, mark the card.
58 if ((HeapWord*)obj < gen_boundary()) {
59 rs()->write_ref_field_gc_par(p, obj);
60 }
61 }
62
63 // NOTE! Any changes made here should also be made
64 // in FastScanClosure::do_oop_work()
65 template <class T> inline void ScanClosure::do_oop_work(T* p) {
66 T heap_oop = oopDesc::load_heap_oop(p);
67 // Should we copy the obj?
68 if (!oopDesc::is_null(heap_oop)) {
69 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
70 if ((HeapWord*)obj < _boundary) {
71 assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
72 oop new_obj = obj->is_forwarded() ? obj->forwardee()
73 : _g->copy_to_survivor_space(obj);
74 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
75 }
76 if (_gc_barrier) {
77 // Now call parent closure
78 do_barrier(p);
79 }
80 }
81 }
82
83 inline void ScanClosure::do_oop_nv(oop* p) { ScanClosure::do_oop_work(p); }
84 inline void ScanClosure::do_oop_nv(narrowOop* p) { ScanClosure::do_oop_work(p); }
85
86 // NOTE! Any changes made here should also be made
87 // in ScanClosure::do_oop_work()
88 template <class T> inline void FastScanClosure::do_oop_work(T* p) {
89 T heap_oop = oopDesc::load_heap_oop(p);
90 // Should we copy the obj?
91 if (!oopDesc::is_null(heap_oop)) {
92 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
93 if ((HeapWord*)obj < _boundary) {
94 assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
95 oop new_obj = obj->is_forwarded() ? obj->forwardee()
96 : _g->copy_to_survivor_space(obj);
97 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
98 if (_gc_barrier) {
99 // Now call parent closure
100 do_barrier(p);
101 }
102 }
103 }
104 }
105
106 inline void FastScanClosure::do_oop_nv(oop* p) { FastScanClosure::do_oop_work(p); }
107 inline void FastScanClosure::do_oop_nv(narrowOop* p) { FastScanClosure::do_oop_work(p); }
108
109 // Note similarity to ScanClosure; the difference is that
110 // the barrier set is taken care of outside this closure.
111 template <class T> inline void ScanWeakRefClosure::do_oop_work(T* p) {
112 assert(!oopDesc::is_null(*p), "null weak reference?");
113 oop obj = oopDesc::load_decode_heap_oop_not_null(p);
114 // weak references are sometimes scanned twice; must check
115 // that to-space doesn't already contain this object
116 if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) {
117 oop new_obj = obj->is_forwarded() ? obj->forwardee()
118 : _g->copy_to_survivor_space(obj);
119 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
120 }
121 }
122
123 inline void ScanWeakRefClosure::do_oop_nv(oop* p) { ScanWeakRefClosure::do_oop_work(p); }
124 inline void ScanWeakRefClosure::do_oop_nv(narrowOop* p) { ScanWeakRefClosure::do_oop_work(p); }