1 /*
2 * Copyright (c) 2011, 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_FIELDSTREAMS_HPP
26 #define SHARE_VM_OOPS_FIELDSTREAMS_HPP
27
28 #include "oops/instanceKlass.hpp"
29 #include "oops/fieldInfo.hpp"
30 #include "runtime/fieldDescriptor.hpp"
31
32 // The is the base class for iteration over the fields array
33 // describing the declared fields in the class. Several subclasses
34 // are provided depending on the kind of iteration required. The
35 // JavaFieldStream is for iterating over regular Java fields and it
36 // generally the preferred iterator. InternalFieldStream only
37 // iterates over fields that have been injected by the JVM.
38 // AllFieldStream exposes all fields and should only be used in rare
39 // cases.
40 class FieldStreamBase : public StackObj {
41
42 protected:
43 Array<u2>* _fields;
44 constantPoolHandle _constants;
45 int _index;
46 int _limit;
47 int _generic_signature_slot;
48 fieldDescriptor _fd_buf;
49
50 FieldInfo* field() const { return FieldInfo::from_field_array(_fields, _index); }
51 InstanceKlass* field_holder() const { return _constants->pool_holder(); }
52
53 int init_generic_signature_start_slot() {
54 int length = _fields->length();
55 int num_fields = _index;
56 int skipped_generic_signature_slots = 0;
57 FieldInfo* fi;
58 AccessFlags flags;
59 /* Scan from 0 to the current _index. Count the number of generic
60 signature slots for field[0] to field[_index - 1]. */
61 for (int i = 0; i < _index; i++) {
62 fi = FieldInfo::from_field_array(_fields, i);
63 flags.set_flags(fi->access_flags());
64 if (flags.field_has_generic_signature()) {
65 length --;
66 skipped_generic_signature_slots ++;
67 }
68 }
69 /* Scan from the current _index. */
70 for (int i = _index; i*FieldInfo::field_slots < length; i++) {
71 fi = FieldInfo::from_field_array(_fields, i);
72 flags.set_flags(fi->access_flags());
73 if (flags.field_has_generic_signature()) {
74 length --;
75 }
76 num_fields ++;
77 }
78 _generic_signature_slot = length + skipped_generic_signature_slots;
79 assert(_generic_signature_slot <= _fields->length(), "");
80 return num_fields;
81 }
82
83 FieldStreamBase(Array<u2>* fields, const constantPoolHandle& constants, int start, int limit) {
84 _fields = fields;
85 _constants = constants;
86 _index = start;
87 int num_fields = init_generic_signature_start_slot();
88 if (limit < start) {
89 _limit = num_fields;
90 } else {
91 _limit = limit;
92 }
93 }
94
95 FieldStreamBase(Array<u2>* fields, const constantPoolHandle& constants) {
96 _fields = fields;
97 _constants = constants;
98 _index = 0;
99 _limit = init_generic_signature_start_slot();
100 }
101
102 public:
103 FieldStreamBase(InstanceKlass* klass) {
104 _fields = klass->fields();
105 _constants = klass->constants();
106 _index = 0;
107 _limit = klass->java_fields_count();
108 init_generic_signature_start_slot();
109 assert(klass == field_holder(), "");
110 }
111
112 // accessors
113 int index() const { return _index; }
114
115 void next() {
116 if (access_flags().field_has_generic_signature()) {
117 _generic_signature_slot ++;
118 assert(_generic_signature_slot <= _fields->length(), "");
119 }
120 _index += 1;
121 }
122 bool done() const { return _index >= _limit; }
123
124 // Accessors for current field
125 AccessFlags access_flags() const {
126 AccessFlags flags;
127 flags.set_flags(field()->access_flags());
128 return flags;
129 }
130
131 void set_access_flags(u2 flags) const {
132 field()->set_access_flags(flags);
133 }
134
135 void set_access_flags(AccessFlags flags) const {
136 set_access_flags(flags.as_short());
137 }
138
139 Symbol* name() const {
140 return field()->name(_constants);
141 }
142
143 Symbol* signature() const {
144 return field()->signature(_constants);
145 }
146
147 Symbol* generic_signature() const {
148 if (access_flags().field_has_generic_signature()) {
149 assert(_generic_signature_slot < _fields->length(), "out of bounds");
150 int index = _fields->at(_generic_signature_slot);
151 return _constants->symbol_at(index);
152 } else {
153 return NULL;
154 }
155 }
156
157 int offset() const {
158 return field()->offset();
159 }
160
161 int allocation_type() const {
162 return field()->allocation_type();
163 }
164
165 bool is_flatten() {
166 return field()->is_flatten();
167 }
168
169 void set_flattening(bool b) {
170 field()->set_flattening(b);
171 }
172
173 void set_offset(int offset) {
174 field()->set_offset(offset);
175 }
176
177 bool is_offset_set() const {
178 return field()->is_offset_set();
179 }
180
181 bool is_contended() const {
182 return field()->is_contended();
183 }
184
185 int contended_group() const {
186 return field()->contended_group();
187 }
188
189 // bridge to a heavier API:
190 fieldDescriptor& field_descriptor() const {
191 fieldDescriptor& field = const_cast<fieldDescriptor&>(_fd_buf);
192 field.reinitialize(field_holder(), _index);
193 return field;
194 }
195 };
196
197 // Iterate over only the internal fields
198 class JavaFieldStream : public FieldStreamBase {
199 public:
200 JavaFieldStream(const InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), 0, k->java_fields_count()) {}
201
202 int name_index() const {
203 assert(!field()->is_internal(), "regular only");
204 return field()->name_index();
205 }
206 void set_name_index(int index) {
207 assert(!field()->is_internal(), "regular only");
208 field()->set_name_index(index);
209 }
210 int signature_index() const {
211 assert(!field()->is_internal(), "regular only");
212 return field()->signature_index();
213 }
214 void set_signature_index(int index) {
215 assert(!field()->is_internal(), "regular only");
216 field()->set_signature_index(index);
217 }
218 int generic_signature_index() const {
219 assert(!field()->is_internal(), "regular only");
220 if (access_flags().field_has_generic_signature()) {
221 assert(_generic_signature_slot < _fields->length(), "out of bounds");
222 return _fields->at(_generic_signature_slot);
223 } else {
224 return 0;
225 }
226 }
227 void set_generic_signature_index(int index) {
228 assert(!field()->is_internal(), "regular only");
229 if (access_flags().field_has_generic_signature()) {
230 assert(_generic_signature_slot < _fields->length(), "out of bounds");
231 _fields->at_put(_generic_signature_slot, index);
232 }
233 }
234 int initval_index() const {
235 assert(!field()->is_internal(), "regular only");
236 return field()->initval_index();
237 }
238 void set_initval_index(int index) {
239 assert(!field()->is_internal(), "regular only");
240 return field()->set_initval_index(index);
241 }
242 };
243
244
245 // Iterate over only the internal fields
246 class InternalFieldStream : public FieldStreamBase {
247 public:
248 InternalFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {}
249 };
250
251
252 class AllFieldStream : public FieldStreamBase {
253 public:
254 AllFieldStream(Array<u2>* fields, const constantPoolHandle& constants): FieldStreamBase(fields, constants) {}
255 AllFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants()) {}
256 };
257
258 #endif // SHARE_VM_OOPS_FIELDSTREAMS_HPP