Mercurial > hg > graal-jvmci-8
annotate src/share/vm/runtime/reflectionUtils.hpp @ 1716:be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
Summary: GC workers now recognize an intermediate transient state of blocks which are allocated but have not yet completed initialization. blk_start() calls do not attempt to determine the size of a block in the transient state, rather waiting for the block to become initialized so that it is safe to query its size. Audited and ensured the order of initialization of object fields (klass, free bit and size) to respect block state transition protocol. Also included some new assertion checking code enabled in debug mode.
Reviewed-by: chrisphi, johnc, poonam
author | ysr |
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date | Mon, 16 Aug 2010 15:58:42 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1999, 2005, Oracle and/or its affiliates. All rights reserved. |
0 | 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 | |
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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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 // A KlassStream is an abstract stream for streaming over self, superclasses | |
26 // and (super)interfaces. Streaming is done in reverse order (subclasses first, | |
27 // interfaces last). | |
28 // | |
29 // for (KlassStream st(k, false, false); !st.eos(); st.next()) { | |
30 // klassOop k = st.klass(); | |
31 // ... | |
32 // } | |
33 | |
34 class KlassStream VALUE_OBJ_CLASS_SPEC { | |
35 protected: | |
36 instanceKlassHandle _klass; // current klass/interface iterated over | |
37 objArrayHandle _interfaces; // transitive interfaces for initial class | |
38 int _interface_index; // current interface being processed | |
39 bool _local_only; // process initial class/interface only | |
40 bool _classes_only; // process classes only (no interfaces) | |
41 int _index; | |
42 | |
43 virtual int length() const = 0; | |
44 | |
45 public: | |
46 // constructor | |
47 KlassStream(instanceKlassHandle klass, bool local_only, bool classes_only); | |
48 | |
49 // testing | |
50 bool eos(); | |
51 | |
52 // iterating | |
53 virtual void next() = 0; | |
54 | |
55 // accessors | |
56 instanceKlassHandle klass() const { return _klass; } | |
57 int index() const { return _index; } | |
58 }; | |
59 | |
60 | |
61 // A MethodStream streams over all methods in a class, superclasses and (super)interfaces. | |
62 // Streaming is done in reverse order (subclasses first, methods in reverse order) | |
63 // Usage: | |
64 // | |
65 // for (MethodStream st(k, false, false); !st.eos(); st.next()) { | |
66 // methodOop m = st.method(); | |
67 // ... | |
68 // } | |
69 | |
70 class MethodStream : public KlassStream { | |
71 private: | |
72 int length() const { return methods()->length(); } | |
73 objArrayOop methods() const { return _klass->methods(); } | |
74 public: | |
75 MethodStream(instanceKlassHandle klass, bool local_only, bool classes_only) | |
76 : KlassStream(klass, local_only, classes_only) { | |
77 _index = length(); | |
78 next(); | |
79 } | |
80 | |
81 void next() { _index--; } | |
82 methodOop method() const { return methodOop(methods()->obj_at(index())); } | |
83 }; | |
84 | |
85 | |
86 // A FieldStream streams over all fields in a class, superclasses and (super)interfaces. | |
87 // Streaming is done in reverse order (subclasses first, fields in reverse order) | |
88 // Usage: | |
89 // | |
90 // for (FieldStream st(k, false, false); !st.eos(); st.next()) { | |
91 // symbolOop field_name = st.name(); | |
92 // ... | |
93 // } | |
94 | |
95 | |
96 class FieldStream : public KlassStream { | |
97 private: | |
98 int length() const { return fields()->length(); } | |
99 constantPoolOop constants() const { return _klass->constants(); } | |
100 protected: | |
101 typeArrayOop fields() const { return _klass->fields(); } | |
102 public: | |
103 FieldStream(instanceKlassHandle klass, bool local_only, bool classes_only) | |
104 : KlassStream(klass, local_only, classes_only) { | |
105 _index = length(); | |
106 next(); | |
107 } | |
108 | |
109 void next() { _index -= instanceKlass::next_offset; } | |
110 | |
111 // Accessors for current field | |
112 AccessFlags access_flags() const { | |
113 AccessFlags flags; | |
114 flags.set_flags(fields()->ushort_at(index() + instanceKlass::access_flags_offset)); | |
115 return flags; | |
116 } | |
117 symbolOop name() const { | |
118 int name_index = fields()->ushort_at(index() + instanceKlass::name_index_offset); | |
119 return constants()->symbol_at(name_index); | |
120 } | |
121 symbolOop signature() const { | |
122 int signature_index = fields()->ushort_at(index() + | |
123 instanceKlass::signature_index_offset); | |
124 return constants()->symbol_at(signature_index); | |
125 } | |
126 // missing: initval() | |
127 int offset() const { | |
128 return _klass->offset_from_fields( index() ); | |
129 } | |
130 }; | |
131 | |
132 class FilteredField { | |
133 private: | |
134 klassOop _klass; | |
135 int _field_offset; | |
136 | |
137 public: | |
138 FilteredField(klassOop klass, int field_offset) { | |
139 _klass = klass; | |
140 _field_offset = field_offset; | |
141 } | |
142 klassOop klass() { return _klass; } | |
143 oop* klass_addr() { return (oop*) &_klass; } | |
144 int field_offset() { return _field_offset; } | |
145 }; | |
146 | |
147 class FilteredFieldsMap : AllStatic { | |
148 private: | |
149 static GrowableArray<FilteredField *> *_filtered_fields; | |
150 public: | |
151 static void initialize(); | |
152 static bool is_filtered_field(klassOop klass, int field_offset) { | |
153 for (int i=0; i < _filtered_fields->length(); i++) { | |
154 if (klass == _filtered_fields->at(i)->klass() && | |
155 field_offset == _filtered_fields->at(i)->field_offset()) { | |
156 return true; | |
157 } | |
158 } | |
159 return false; | |
160 } | |
161 static int filtered_fields_count(klassOop klass, bool local_only) { | |
162 int nflds = 0; | |
163 for (int i=0; i < _filtered_fields->length(); i++) { | |
164 if (local_only && klass == _filtered_fields->at(i)->klass()) { | |
165 nflds++; | |
166 } else if (klass->klass_part()->is_subtype_of(_filtered_fields->at(i)->klass())) { | |
167 nflds++; | |
168 } | |
169 } | |
170 return nflds; | |
171 } | |
172 // GC support. | |
173 static void klasses_oops_do(OopClosure* f) { | |
174 for (int i = 0; i < _filtered_fields->length(); i++) { | |
175 f->do_oop((oop*)_filtered_fields->at(i)->klass_addr()); | |
176 } | |
177 } | |
178 }; | |
179 | |
180 | |
181 // A FilteredFieldStream streams over all fields in a class, superclasses and | |
182 // (super)interfaces. Streaming is done in reverse order (subclasses first, | |
183 // fields in reverse order) | |
184 // | |
185 // Usage: | |
186 // | |
187 // for (FilteredFieldStream st(k, false, false); !st.eos(); st.next()) { | |
188 // symbolOop field_name = st.name(); | |
189 // ... | |
190 // } | |
191 | |
192 class FilteredFieldStream : public FieldStream { | |
193 private: | |
194 int _filtered_fields_count; | |
195 bool has_filtered_field() { return (_filtered_fields_count > 0); } | |
196 | |
197 public: | |
198 FilteredFieldStream(instanceKlassHandle klass, bool local_only, bool classes_only) | |
199 : FieldStream(klass, local_only, classes_only) { | |
200 _filtered_fields_count = FilteredFieldsMap::filtered_fields_count((klassOop)klass(), local_only); | |
201 } | |
202 int field_count(); | |
203 void next() { | |
204 _index -= instanceKlass::next_offset; | |
205 if (has_filtered_field()) { | |
206 while (_index >=0 && FilteredFieldsMap::is_filtered_field((klassOop)_klass(), offset())) { | |
207 _index -= instanceKlass::next_offset; | |
208 } | |
209 } | |
210 } | |
211 }; |