1 /*
2 * Copyright (c) 2011, 2012, 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_FIELDSTREAMS_HPP
26 #define SHARE_VM_OOPS_FIELDSTREAMS_HPP
27
28 #include "oops/instanceKlass.hpp"
29 #include "oops/fieldInfo.hpp"
30
31 // The is the base class for iteration over the fields array
32 // describing the declared fields in the class. Several subclasses
33 // are provided depending on the kind of iteration required. The
34 // JavaFieldStream is for iterating over regular Java fields and it
35 // generally the preferred iterator. InternalFieldStream only
36 // iterates over fields that have been injected by the JVM.
37 // AllFieldStream exposes all fields and should only be used in rare
38 // cases.
39 class FieldStreamBase : public StackObj {
40 protected:
41 Array<u2>* _fields;
42 constantPoolHandle _constants;
43 int _index;
44 int _limit;
45 int _generic_signature_slot;
46
47 FieldInfo* field() const { return FieldInfo::from_field_array(_fields, _index); }
48
49 int init_generic_signature_start_slot() {
50 int length = _fields->length();
51 int num_fields = 0;
52 int skipped_generic_signature_slots = 0;
53 FieldInfo* fi;
54 AccessFlags flags;
55 /* Scan from 0 to the current _index. Count the number of generic
56 signature slots for field[0] to field[_index - 1]. */
57 for (int i = 0; i < _index; i++) {
58 fi = FieldInfo::from_field_array(_fields, i);
59 flags.set_flags(fi->access_flags());
60 if (flags.field_has_generic_signature()) {
61 length --;
62 skipped_generic_signature_slots ++;
63 }
64 }
65 /* Scan from the current _index. */
66 for (int i = _index; i*FieldInfo::field_slots < length; i++) {
67 fi = FieldInfo::from_field_array(_fields, i);
68 flags.set_flags(fi->access_flags());
69 if (flags.field_has_generic_signature()) {
70 length --;
71 }
72 num_fields ++;
73 }
74 _generic_signature_slot = length + skipped_generic_signature_slots;
75 assert(_generic_signature_slot <= _fields->length(), "");
76 return num_fields;
77 }
78
79 FieldStreamBase(Array<u2>* fields, constantPoolHandle constants, int start, int limit) {
80 _fields = fields;
81 _constants = constants;
82 _index = start;
83 int num_fields = init_generic_signature_start_slot();
84 if (limit < start) {
85 _limit = num_fields;
86 } else {
87 _limit = limit;
88 }
89 }
90
91 FieldStreamBase(Array<u2>* fields, constantPoolHandle constants) {
92 _fields = fields;
93 _constants = constants;
94 _index = 0;
95 _limit = init_generic_signature_start_slot();
96 }
97
98 public:
99 FieldStreamBase(InstanceKlass* klass) {
100 _fields = klass->fields();
101 _constants = klass->constants();
102 _index = 0;
103 _limit = klass->java_fields_count();
104 init_generic_signature_start_slot();
105 }
106 FieldStreamBase(instanceKlassHandle klass) {
107 _fields = klass->fields();
108 _constants = klass->constants();
109 _index = 0;
110 _limit = klass->java_fields_count();
111 init_generic_signature_start_slot();
112 }
113
114 // accessors
115 int index() const { return _index; }
116
117 void next() {
118 if (access_flags().field_has_generic_signature()) {
119 _generic_signature_slot ++;
120 assert(_generic_signature_slot <= _fields->length(), "");
121 }
122 _index += 1;
123 }
124 bool done() const { return _index >= _limit; }
125
126 // Accessors for current field
127 AccessFlags access_flags() const {
128 AccessFlags flags;
129 flags.set_flags(field()->access_flags());
130 return flags;
131 }
132
133 void set_access_flags(u2 flags) const {
134 field()->set_access_flags(flags);
135 }
136
137 void set_access_flags(AccessFlags flags) const {
138 set_access_flags(flags.as_short());
139 }
140
141 Symbol* name() const {
142 return field()->name(_constants);
143 }
144
145 Symbol* signature() const {
146 return field()->signature(_constants);
147 }
148
149 Symbol* generic_signature() const {
150 if (access_flags().field_has_generic_signature()) {
151 assert(_generic_signature_slot < _fields->length(), "out of bounds");
152 int index = _fields->at(_generic_signature_slot);
153 return _constants->symbol_at(index);
154 } else {
155 return NULL;
156 }
157 }
158
159 int offset() const {
160 return field()->offset();
161 }
162
163 int allocation_type() const {
164 return field()->allocation_type();
165 }
166
167 void set_offset(int offset) {
168 field()->set_offset(offset);
169 }
170
171 bool is_offset_set() const {
172 return field()->is_offset_set();
173 }
174
175 bool is_contended() const {
176 return field()->is_contended();
177 }
178
179 int contended_group() const {
180 return field()->contended_group();
181 }
182
183 };
184
185 // Iterate over only the internal fields
186 class JavaFieldStream : public FieldStreamBase {
187 public:
188 JavaFieldStream(instanceKlassHandle k): FieldStreamBase(k->fields(), k->constants(), 0, k->java_fields_count()) {}
189
190 int name_index() const {
191 assert(!field()->is_internal(), "regular only");
192 return field()->name_index();
193 }
194 void set_name_index(int index) {
195 assert(!field()->is_internal(), "regular only");
196 field()->set_name_index(index);
197 }
198 int signature_index() const {
199 assert(!field()->is_internal(), "regular only");
200 return field()->signature_index();
201 }
202 void set_signature_index(int index) {
203 assert(!field()->is_internal(), "regular only");
204 field()->set_signature_index(index);
205 }
206 int generic_signature_index() const {
207 assert(!field()->is_internal(), "regular only");
208 if (access_flags().field_has_generic_signature()) {
209 assert(_generic_signature_slot < _fields->length(), "out of bounds");
210 return _fields->at(_generic_signature_slot);
211 } else {
212 return 0;
213 }
214 }
215 void set_generic_signature_index(int index) {
216 assert(!field()->is_internal(), "regular only");
217 if (access_flags().field_has_generic_signature()) {
218 assert(_generic_signature_slot < _fields->length(), "out of bounds");
219 _fields->at_put(_generic_signature_slot, index);
220 }
221 }
222 int initval_index() const {
223 assert(!field()->is_internal(), "regular only");
224 return field()->initval_index();
225 }
226 void set_initval_index(int index) {
227 assert(!field()->is_internal(), "regular only");
228 return field()->set_initval_index(index);
229 }
230 };
231
232
233 // Iterate over only the internal fields
234 class InternalFieldStream : public FieldStreamBase {
235 public:
236 InternalFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {}
237 InternalFieldStream(instanceKlassHandle k): FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {}
238 };
239
240
241 class AllFieldStream : public FieldStreamBase {
242 public:
243 AllFieldStream(Array<u2>* fields, constantPoolHandle constants): FieldStreamBase(fields, constants) {}
244 AllFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants()) {}
245 AllFieldStream(instanceKlassHandle k): FieldStreamBase(k->fields(), k->constants()) {}
246 };
247
248 #endif // SHARE_VM_OOPS_FIELDSTREAMS_HPP