1 /*
2 * Copyright (c) 1997, 2017, 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_OOPS_INSTANCEREFKLASS_HPP
26 #define SHARE_VM_OOPS_INSTANCEREFKLASS_HPP
27
28 #include "gc/shared/specialized_oop_closures.hpp"
29 #include "oops/instanceKlass.hpp"
30 #include "utilities/macros.hpp"
31
32 class ClassFileParser;
33
34 // An InstanceRefKlass is a specialized InstanceKlass for Java
35 // classes that are subclasses of java/lang/ref/Reference.
36 //
37 // These classes are used to implement soft/weak/final/phantom
38 // references and finalization, and need special treatment by the
39 // garbage collector.
40 //
41 // During GC discovered reference objects are added (chained) to one
42 // of the four lists below, depending on the type of reference.
43 // The linked occurs through the next field in class java/lang/ref/Reference.
44 //
45 // Afterwards, the discovered references are processed in decreasing
46 // order of reachability. Reference objects eligible for notification
47 // are linked to the static pending_list in class java/lang/ref/Reference,
48 // and the pending list lock object in the same class is notified.
49
50
51 class InstanceRefKlass: public InstanceKlass {
52 friend class InstanceKlass;
53 private:
54 InstanceRefKlass(const ClassFileParser& parser) : InstanceKlass(parser, InstanceKlass::_misc_kind_reference) {}
55
56 public:
57 InstanceRefKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
58
59 // GC specific object visitors
60 //
61 #if INCLUDE_ALL_GCS
62 // Parallel Scavenge
63 void oop_ps_push_contents( oop obj, PSPromotionManager* pm);
64 // Parallel Compact
65 void oop_pc_follow_contents(oop obj, ParCompactionManager* cm);
66 void oop_pc_update_pointers(oop obj, ParCompactionManager* cm);
67 #endif
68
69 // Oop fields (and metadata) iterators
70 // [nv = true] Use non-virtual calls to do_oop_nv.
71 // [nv = false] Use virtual calls to do_oop.
72 //
73 // The InstanceRefKlass iterators also support reference processing.
74
75
76 // Forward iteration
77 private:
78 // Iterate over all oop fields and metadata.
79 template <bool nv, class OopClosureType>
80 inline void oop_oop_iterate(oop obj, OopClosureType* closure);
81
82 // Reverse iteration
83 #if INCLUDE_ALL_GCS
84 // Iterate over all oop fields and metadata.
85 template <bool nv, class OopClosureType>
86 inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
87 #endif // INCLUDE_ALL_GCS
88
89 // Bounded range iteration
90 // Iterate over all oop fields and metadata.
91 template <bool nv, class OopClosureType>
92 inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
93
94 // Reference processing part of the iterators.
95
96 // Specialized for [T = oop] or [T = narrowOop].
97 template <bool nv, typename T, class OopClosureType, class Contains>
98 inline void oop_oop_iterate_ref_processing_specialized(oop obj, OopClosureType* closure, Contains& contains);
99
100 // Only perform reference processing if the referent object is within mr.
101 template <bool nv, class OopClosureType>
102 inline void oop_oop_iterate_ref_processing_bounded(oop obj, OopClosureType* closure, MemRegion mr);
103
104 // Reference processing
105 template <bool nv, class OopClosureType>
106 inline void oop_oop_iterate_ref_processing(oop obj, OopClosureType* closure);
107
108 // Building blocks for specialized handling.
109 template <bool nv, typename T, class OopClosureType, class Contains>
110 static void do_referent(oop obj, OopClosureType* closure, Contains& contains);
111
112 template <bool nv, typename T, class OopClosureType, class Contains>
113 static void do_next(oop obj, OopClosureType* closure, Contains& contains);
114
115 template <bool nv, typename T, class OopClosureType, class Contains>
116 static void do_discovered(oop obj, OopClosureType* closure, Contains& contains);
117
118 template <typename T, class OopClosureType>
119 static bool try_discover(oop obj, ReferenceType type, OopClosureType* closure);
120
121 // Do discovery while handling InstanceRefKlasses. Reference discovery
122 // is only done if the closure provides a ReferenceProcessor.
123 template <bool nv, typename T, class OopClosureType, class Contains>
124 static void oop_oop_iterate_discovery(oop obj, ReferenceType type, OopClosureType* closure, Contains& contains);
125
126 // Used for a special case in G1 where the closure needs to be applied
127 // to the discovered field. Reference discovery is also done if the
128 // closure provides a ReferenceProcessor.
129 template <bool nv, typename T, class OopClosureType, class Contains>
130 static void oop_oop_iterate_discovered_and_discovery(oop obj, ReferenceType type, OopClosureType* closure, Contains& contains);
131
132 // Apply the closure to all fields. No reference discovery is done.
133 template <bool nv, typename T, class OopClosureType, class Contains>
134 static void oop_oop_iterate_fields(oop obj, OopClosureType* closure, Contains& contains);
135
136 template <typename T>
137 static void trace_reference_gc(const char *s, oop obj) NOT_DEBUG_RETURN;
138
139 public:
140
141 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL)
142 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL)
143
144 #if INCLUDE_ALL_GCS
145 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL_BACKWARDS)
146 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL_BACKWARDS)
147 #endif // INCLUDE_ALL_GCS
148
149 // Update non-static oop maps so 'referent', 'nextPending' and
150 // 'discovered' will look like non-oops
151 static void update_nonstatic_oop_maps(Klass* k);
152
153 public:
154 // Verification
155 void oop_verify_on(oop obj, outputStream* st);
156 };
157
158 #endif // SHARE_VM_OOPS_INSTANCEREFKLASS_HPP