1 /*
2 * Copyright (c) 1997, 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.
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23 */
24
25 #ifndef SHARE_VM_OOPS_INSTANCEREFKLASS_HPP
26 #define SHARE_VM_OOPS_INSTANCEREFKLASS_HPP
27
28 #include "oops/instanceKlass.hpp"
29
30 // An instanceRefKlass is a specialized instanceKlass for Java
31 // classes that are subclasses of java/lang/ref/Reference.
32 //
33 // These classes are used to implement soft/weak/final/phantom
34 // references and finalization, and need special treatment by the
35 // garbage collector.
36 //
37 // During GC discovered reference objects are added (chained) to one
38 // of the four lists below, depending on the type of reference.
39 // The linked occurs through the next field in class java/lang/ref/Reference.
40 //
41 // Afterwards, the discovered references are processed in decreasing
42 // order of reachability. Reference objects eligible for notification
43 // are linked to the static pending_list in class java/lang/ref/Reference,
44 // and the pending list lock object in the same class is notified.
45
46
47 class instanceRefKlass: public instanceKlass {
48 public:
49 // Type testing
50 bool oop_is_instanceRef() const { return true; }
51
52 // Casting from klassOop
53 static instanceRefKlass* cast(klassOop k) {
54 assert(k->klass_part()->oop_is_instanceRef(), "cast to instanceRefKlass");
55 return (instanceRefKlass*) k->klass_part();
56 }
57
58 // allocation
59 DEFINE_ALLOCATE_PERMANENT(instanceRefKlass);
60
61 // Garbage collection
62 int oop_adjust_pointers(oop obj);
63 void oop_follow_contents(oop obj);
64
65 // Parallel Scavenge and Parallel Old
66 PARALLEL_GC_DECLS
67
68 int oop_oop_iterate(oop obj, OopClosure* blk) {
69 return oop_oop_iterate_v(obj, blk);
70 }
71 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) {
72 return oop_oop_iterate_v_m(obj, blk, mr);
73 }
74
75 #define InstanceRefKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
76 int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk); \
77 int oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk, MemRegion mr);
78
79 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DECL)
80 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DECL)
81
82 #ifndef SERIALGC
83 #define InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
84 int oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
85
86 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
87 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
88 #endif // !SERIALGC
89
90 static void release_and_notify_pending_list_lock(BasicLock *pending_list_basic_lock);
91 static void acquire_pending_list_lock(BasicLock *pending_list_basic_lock);
92
93 // Update non-static oop maps so 'referent', 'nextPending' and
94 // 'discovered' will look like non-oops
95 static void update_nonstatic_oop_maps(klassOop k);
96
97 public:
98 // Verification
99 void oop_verify_on(oop obj, outputStream* st);
100 };
101
102 #endif // SHARE_VM_OOPS_INSTANCEREFKLASS_HPP