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 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 189 class 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 237 class InternalFieldStream : public FieldStreamBase { 238 public: 239 InternalFieldStream(InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {} 240 }; 241 242 243 class 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_VM_OOPS_FIELDSTREAMS_HPP