1 /*
2 * Copyright (c) 2001, 2015, 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.
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23 */
24
25 #ifndef SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP
26 #define SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP
27
28 #include "memory/iterator.hpp"
29 #include "oops/oop.hpp"
30
31 class Generation;
32 class HeapWord;
33 class CardTableRS;
34 class CardTableModRefBS;
35 class DefNewGeneration;
36 class KlassRemSet;
37
38 // Closure for iterating roots from a particular generation
39 // Note: all classes deriving from this MUST call this do_barrier
40 // method at the end of their own do_oop method!
41 // Note: no do_oop defined, this is an abstract class.
42
43 class OopsInGenClosure : public ExtendedOopClosure {
44 private:
45 Generation* _gen; // generation being scanned
46
47 protected:
48 // Some subtypes need access.
49 HeapWord* _gen_boundary; // start of generation
50 CardTableRS* _rs; // remembered set
51
52 // For assertions
53 Generation* generation() { return _gen; }
54 CardTableRS* rs() { return _rs; }
55
56 // Derived classes that modify oops so that they might be old-to-young
57 // pointers must call the method below.
58 template <class T> void do_barrier(T* p);
59
60 // Version for use by closures that may be called in parallel code.
61 template <class T> void par_do_barrier(T* p);
62
63 public:
64 OopsInGenClosure() : ExtendedOopClosure(NULL),
65 _gen(NULL), _gen_boundary(NULL), _rs(NULL) {};
66
67 OopsInGenClosure(Generation* gen);
68
69 // Problem with static closures: must have _gen_boundary set at some point,
70 // but cannot do this until after the heap is initialized.
71 void set_generation(Generation* gen);
72 void assert_generation(Generation* gen);
73
74 HeapWord* gen_boundary() { return _gen_boundary; }
75 };
76
77 // Super class for scan closures. It contains code to dirty scanned Klasses.
78 class OopsInKlassOrGenClosure: public OopsInGenClosure {
79 Klass* _scanned_klass;
80 public:
81 OopsInKlassOrGenClosure(Generation* g) : OopsInGenClosure(g), _scanned_klass(NULL) {}
82 void set_scanned_klass(Klass* k) {
83 assert(k == NULL || _scanned_klass == NULL, "Must be");
84 _scanned_klass = k;
85 }
86 bool is_scanning_a_klass() { return _scanned_klass != NULL; }
87 void do_klass_barrier();
88 };
89
90 // Closure for scanning DefNewGeneration.
91 //
92 // This closure will perform barrier store calls for ALL
93 // pointers in scanned oops.
94 class ScanClosure: public OopsInKlassOrGenClosure {
95 protected:
96 DefNewGeneration* _g;
97 HeapWord* _boundary;
98 bool _gc_barrier;
99 template <class T> inline void do_oop_work(T* p);
100 public:
101 ScanClosure(DefNewGeneration* g, bool gc_barrier);
102 virtual void do_oop(oop* p);
103 virtual void do_oop(narrowOop* p);
104 inline void do_oop_nv(oop* p);
105 inline void do_oop_nv(narrowOop* p);
106 };
107
108 // Closure for scanning DefNewGeneration.
109 //
110 // This closure only performs barrier store calls on
111 // pointers into the DefNewGeneration. This is less
112 // precise, but faster, than a ScanClosure
113 class FastScanClosure: public OopsInKlassOrGenClosure {
114 protected:
115 DefNewGeneration* _g;
116 HeapWord* _boundary;
117 bool _gc_barrier;
118 template <class T> inline void do_oop_work(T* p);
119 public:
120 FastScanClosure(DefNewGeneration* g, bool gc_barrier);
121 virtual void do_oop(oop* p);
122 virtual void do_oop(narrowOop* p);
123 inline void do_oop_nv(oop* p);
124 inline void do_oop_nv(narrowOop* p);
125 };
126
127 class KlassScanClosure: public KlassClosure {
128 OopsInKlassOrGenClosure* _scavenge_closure;
129 // true if the the modified oops state should be saved.
130 bool _accumulate_modified_oops;
131 public:
132 KlassScanClosure(OopsInKlassOrGenClosure* scavenge_closure,
133 KlassRemSet* klass_rem_set_policy);
134 void do_klass(Klass* k);
135 };
136
137 class FilteringClosure: public ExtendedOopClosure {
138 private:
139 HeapWord* _boundary;
140 ExtendedOopClosure* _cl;
141 protected:
142 template <class T> inline void do_oop_work(T* p) {
143 T heap_oop = oopDesc::load_heap_oop(p);
144 if (!oopDesc::is_null(heap_oop)) {
145 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
146 if ((HeapWord*)obj < _boundary) {
147 _cl->do_oop(p);
148 }
149 }
150 }
151 public:
152 FilteringClosure(HeapWord* boundary, ExtendedOopClosure* cl) :
153 ExtendedOopClosure(cl->_ref_processor), _boundary(boundary),
154 _cl(cl) {}
155 virtual void do_oop(oop* p);
156 virtual void do_oop(narrowOop* p);
157 inline void do_oop_nv(oop* p) { FilteringClosure::do_oop_work(p); }
158 inline void do_oop_nv(narrowOop* p) { FilteringClosure::do_oop_work(p); }
159 virtual bool do_metadata() { return do_metadata_nv(); }
160 inline bool do_metadata_nv() { assert(!_cl->do_metadata(), "assumption broken, must change to 'return _cl->do_metadata()'"); return false; }
161 };
162
163 // Closure for scanning DefNewGeneration's weak references.
164 // NOTE: very much like ScanClosure but not derived from
165 // OopsInGenClosure -- weak references are processed all
166 // at once, with no notion of which generation they were in.
167 class ScanWeakRefClosure: public OopClosure {
168 protected:
169 DefNewGeneration* _g;
170 HeapWord* _boundary;
171 template <class T> inline void do_oop_work(T* p);
172 public:
173 ScanWeakRefClosure(DefNewGeneration* g);
174 virtual void do_oop(oop* p);
175 virtual void do_oop(narrowOop* p);
176 inline void do_oop_nv(oop* p);
177 inline void do_oop_nv(narrowOop* p);
178 };
179
180 #endif // SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP