1/*
2 * Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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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.
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23 */
24
25#ifndef SHARE_OOPS_FIELDSTREAMS_HPP
26#define SHARE_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.
40class FieldStreamBase : public StackObj {
41 protected:
42 Array<u2>* _fields;
43 constantPoolHandle _constants;
44 int _index;
45 int _limit;
46 int _generic_signature_slot;
47 fieldDescriptor _fd_buf;
48
49 FieldInfo* field() const { return FieldInfo::from_field_array(_fields, _index); }
50 InstanceKlass* field_holder() const { return _constants->pool_holder(); }
51
52 int init_generic_signature_start_slot() {
53 int length = _fields->length();
54 int num_fields = _index;
55 int skipped_generic_signature_slots = 0;
56 FieldInfo* fi;
57 AccessFlags flags;
58 /* Scan from 0 to the current _index. Count the number of generic
59 signature slots for field[0] to field[_index - 1]. */
60 for (int i = 0; i < _index; i++) {
61 fi = FieldInfo::from_field_array(_fields, i);
62 flags.set_flags(fi->access_flags());
63 if (flags.field_has_generic_signature()) {
64 length --;
65 skipped_generic_signature_slots ++;
66 }
67 }
68 /* Scan from the current _index. */
69 for (int i = _index; i*FieldInfo::field_slots < length; i++) {
70 fi = FieldInfo::from_field_array(_fields, i);
71 flags.set_flags(fi->access_flags());
72 if (flags.field_has_generic_signature()) {
73 length --;
74 }
75 num_fields ++;
76 }
77 _generic_signature_slot = length + skipped_generic_signature_slots;
78 assert(_generic_signature_slot <= _fields->length(), "");
79 return num_fields;
80 }
81
82 FieldStreamBase(Array<u2>* fields, const constantPoolHandle& constants, int start, int limit) {
83 _fields = fields;
84 _constants = constants;
85 _index = start;
86 int num_fields = init_generic_signature_start_slot();
87 if (limit < start) {
88 _limit = num_fields;
89 } else {
90 _limit = limit;
91 }
92 }
93
94 FieldStreamBase(Array<u2>* fields, const constantPoolHandle& constants) {
95 _fields = fields;
96 _constants = constants;
97 _index = 0;
98 _limit = init_generic_signature_start_slot();
99 }
100
101 public:
102 FieldStreamBase(InstanceKlass* klass) {
103 _fields = klass->fields();
104 _constants = klass->constants();
105 _index = 0;
106 _limit = klass->java_fields_count();
107 init_generic_signature_start_slot();
108 assert(klass == field_holder(), "");
109 }
110
111 // accessors
112 int index() const { return _index; }
113
114 void next() {
115 if (access_flags().field_has_generic_signature()) {
116 _generic_signature_slot ++;
117 assert(_generic_signature_slot <= _fields->length(), "");
118 }
119 _index += 1;
120 }
121 bool done() const { return _index >= _limit; }
122
123 // Accessors for current field
124 AccessFlags access_flags() const {
125 AccessFlags flags;
126 flags.set_flags(field()->access_flags());
127 return flags;
128 }
129
130 void set_access_flags(u2 flags) const {
131 field()->set_access_flags(flags);
132 }
133
134 void set_access_flags(AccessFlags flags) const {
135 set_access_flags(flags.as_short());
136 }
137
138 Symbol* name() const {
139 return field()->name(_constants);
140 }
141
142 Symbol* signature() const {
143 return field()->signature(_constants);
144 }
145
146 Symbol* generic_signature() const {
147 if (access_flags().field_has_generic_signature()) {
148 assert(_generic_signature_slot < _fields->length(), "out of bounds");
149 int index = _fields->at(_generic_signature_slot);
150 return _constants->symbol_at(index);
151 } else {
152 return NULL;
153 }
154 }
155
156 int offset() const {
157 return field()->offset();
158 }
159
160 int allocation_type() const {
161 return field()->allocation_type();
162 }
163
164 void set_offset(int offset) {
165 field()->set_offset(offset);
166 }
167
168 bool is_offset_set() const {
169 return field()->is_offset_set();
170 }
171
172 bool is_contended() const {
173 return field()->is_contended();
174 }
175
176 int contended_group() const {
177 return field()->contended_group();
178 }
179
180 // bridge to a heavier API:
181 fieldDescriptor& field_descriptor() const {
182 fieldDescriptor& field = const_cast<fieldDescriptor&>(_fd_buf);
183 field.reinitialize(field_holder(), _index);
184 return field;
185 }
186};
187
188// Iterate over only the internal fields
189class JavaFieldStream : public FieldStreamBase {
190 public:
191 JavaFieldStream(const InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), 0, k->java_fields_count()) {}
192
193 int name_index() const {
194 assert(!field()->is_internal(), "regular only");
195 return field()->name_index();
196 }
197 void set_name_index(int index) {
198 assert(!field()->is_internal(), "regular only");
199 field()->set_name_index(index);
200 }
201 int signature_index() const {
202 assert(!field()->is_internal(), "regular only");
203 return field()->signature_index();
204 }
205 void set_signature_index(int index) {
206 assert(!field()->is_internal(), "regular only");
207 field()->set_signature_index(index);
208 }
209 int generic_signature_index() const {
210 assert(!field()->is_internal(), "regular only");
211 if (access_flags().field_has_generic_signature()) {
212 assert(_generic_signature_slot < _fields->length(), "out of bounds");
213 return _fields->at(_generic_signature_slot);
214 } else {
215 return 0;
216 }
217 }
218 void set_generic_signature_index(int index) {
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 _fields->at_put(_generic_signature_slot, index);
223 }
224 }
225 int initval_index() const {
226 assert(!field()->is_internal(), "regular only");
227 return field()->initval_index();
228 }
229 void set_initval_index(int index) {
230 assert(!field()->is_internal(), "regular only");
231 return field()->set_initval_index(index);
232 }
233};
234
235
236// Iterate over only the internal fields
237class InternalFieldStream : public FieldStreamBase {
238 public:
239 InternalFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {}
240};
241
242
243class AllFieldStream : public FieldStreamBase {
244 public:
245 AllFieldStream(Array<u2>* fields, const constantPoolHandle& constants): FieldStreamBase(fields, constants) {}
246 AllFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants()) {}
247};
248
249#endif // SHARE_OOPS_FIELDSTREAMS_HPP
250