1 /*
2 * Copyright (c) 2011, 2020, 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_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.
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
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 inline FieldStreamBase(Array<u2>* fields, ConstantPool* constants, int start, int limit);
83
84 inline FieldStreamBase(Array<u2>* fields, ConstantPool* constants);
85 public:
86 inline FieldStreamBase(InstanceKlass* klass);
87
88 // accessors
89 int index() const { return _index; }
90 InstanceKlass* field_holder() const { return _constants->pool_holder(); }
91
92 void next() {
93 if (access_flags().field_has_generic_signature()) {
94 _generic_signature_slot ++;
95 assert(_generic_signature_slot <= _fields->length(), "");
96 }
97 _index += 1;
98 }
99 bool done() const { return _index >= _limit; }
100
101 // Accessors for current field
102 AccessFlags access_flags() const {
103 AccessFlags flags;
104 flags.set_flags(field()->access_flags());
105 return flags;
106 }
107
108 void set_access_flags(u2 flags) const {
109 field()->set_access_flags(flags);
110 }
111
112 void set_access_flags(AccessFlags flags) const {
113 set_access_flags(flags.as_short());
114 }
115
116 Symbol* name() const {
117 return field()->name(_constants());
118 }
119
120 Symbol* signature() const {
121 return field()->signature(_constants());
122 }
123
124 Symbol* generic_signature() const {
125 if (access_flags().field_has_generic_signature()) {
126 assert(_generic_signature_slot < _fields->length(), "out of bounds");
127 int index = _fields->at(_generic_signature_slot);
128 return _constants->symbol_at(index);
129 } else {
130 return NULL;
131 }
132 }
133
134 int offset() const {
135 return field()->offset();
136 }
137
138 bool is_inlined() {
139 return field()->is_inlined();
140 }
141
142 void set_inlined(bool b) {
143 field()->set_inlined(b);
144 }
145
146 void set_offset(int offset) {
147 field()->set_offset(offset);
148 }
149
150 bool is_offset_set() const {
151 return field()->is_offset_set();
152 }
153
154 bool is_contended() const {
155 return field()->is_contended();
156 }
157
158 int contended_group() const {
159 return field()->contended_group();
160 }
161
162 // bridge to a heavier API:
163 fieldDescriptor& field_descriptor() const {
164 fieldDescriptor& field = const_cast<fieldDescriptor&>(_fd_buf);
165 field.reinitialize(field_holder(), _index);
166 return field;
167 }
168 };
169
170 // Iterate over only the internal fields
171 class JavaFieldStream : public FieldStreamBase {
172 public:
173 JavaFieldStream(const InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), 0, k->java_fields_count()) {}
174
175 int name_index() const {
176 assert(!field()->is_internal(), "regular only");
177 return field()->name_index();
178 }
179 void set_name_index(int index) {
180 assert(!field()->is_internal(), "regular only");
181 field()->set_name_index(index);
182 }
183 int signature_index() const {
184 assert(!field()->is_internal(), "regular only");
185 return field()->signature_index();
186 }
187 void set_signature_index(int index) {
188 assert(!field()->is_internal(), "regular only");
189 field()->set_signature_index(index);
190 }
191 int generic_signature_index() const {
192 assert(!field()->is_internal(), "regular only");
193 if (access_flags().field_has_generic_signature()) {
194 assert(_generic_signature_slot < _fields->length(), "out of bounds");
195 return _fields->at(_generic_signature_slot);
196 } else {
197 return 0;
198 }
199 }
200 void set_generic_signature_index(int index) {
201 assert(!field()->is_internal(), "regular only");
202 if (access_flags().field_has_generic_signature()) {
203 assert(_generic_signature_slot < _fields->length(), "out of bounds");
204 _fields->at_put(_generic_signature_slot, index);
205 }
206 }
207 int initval_index() const {
208 assert(!field()->is_internal(), "regular only");
209 return field()->initval_index();
210 }
211 void set_initval_index(int index) {
212 assert(!field()->is_internal(), "regular only");
213 return field()->set_initval_index(index);
214 }
215 };
216
217
218 // Iterate over only the internal fields
219 class InternalFieldStream : public FieldStreamBase {
220 public:
221 InternalFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {}
222 };
223
224
225 class AllFieldStream : public FieldStreamBase {
226 public:
227 AllFieldStream(Array<u2>* fields, ConstantPool* constants): FieldStreamBase(fields, constants) {}
228 AllFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants()) {}
229 };
230
231 #endif // SHARE_OOPS_FIELDSTREAMS_HPP