1 /* 2 * Copyright (c) 1997, 2024, 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_CONSTANTPOOL_HPP 26 #define SHARE_OOPS_CONSTANTPOOL_HPP 27 28 #include "memory/allocation.hpp" 29 #include "oops/arrayOop.hpp" 30 #include "oops/cpCache.hpp" 31 #include "oops/objArrayOop.hpp" 32 #include "oops/oopHandle.hpp" 33 #include "oops/symbol.hpp" 34 #include "oops/typeArrayOop.hpp" 35 #include "runtime/handles.hpp" 36 #include "runtime/javaThread.hpp" 37 #include "utilities/align.hpp" 38 #include "utilities/bytes.hpp" 39 #include "utilities/constantTag.hpp" 40 #include "utilities/resourceHash.hpp" 41 42 // A ConstantPool is an array containing class constants as described in the 43 // class file. 44 // 45 // Most of the constant pool entries are written during class parsing, which 46 // is safe. For klass types, the constant pool entry is 47 // modified when the entry is resolved. If a klass constant pool 48 // entry is read without a lock, only the resolved state guarantees that 49 // the entry in the constant pool is a klass object and not a Symbol*. 50 51 // This represents a JVM_CONSTANT_Class, JVM_CONSTANT_UnresolvedClass, or 52 // JVM_CONSTANT_UnresolvedClassInError slot in the constant pool. 53 class CPKlassSlot { 54 // cp->symbol_at(_name_index) gives the name of the class. 55 int _name_index; 56 57 // cp->_resolved_klasses->at(_resolved_klass_index) gives the Klass* for the class. 58 int _resolved_klass_index; 59 public: 60 enum { 61 // This is used during constant pool merging where the resolved klass index is 62 // not yet known, and will be computed at a later stage (during a call to 63 // initialize_unresolved_klasses()). 64 _temp_resolved_klass_index = 0xffff 65 }; 66 CPKlassSlot(int n, int rk) { 67 _name_index = n; 68 _resolved_klass_index = rk; 69 } 70 int name_index() const { 71 return _name_index; 72 } 73 int resolved_klass_index() const { 74 assert(_resolved_klass_index != _temp_resolved_klass_index, "constant pool merging was incomplete"); 75 return _resolved_klass_index; 76 } 77 }; 78 79 class ConstantPool : public Metadata { 80 friend class VMStructs; 81 friend class JVMCIVMStructs; 82 friend class BytecodeInterpreter; // Directly extracts a klass in the pool for fast instanceof/checkcast 83 friend class Universe; // For null constructor 84 friend class ClassPrelinker; // CDS 85 private: 86 // If you add a new field that points to any metaspace object, you 87 // must add this field to ConstantPool::metaspace_pointers_do(). 88 Array<u1>* _tags; // the tag array describing the constant pool's contents 89 ConstantPoolCache* _cache; // the cache holding interpreter runtime information 90 InstanceKlass* _pool_holder; // the corresponding class 91 Array<u2>* _operands; // for variable-sized (InvokeDynamic) nodes, usually empty 92 93 // Consider using an array of compressed klass pointers to 94 // save space on 64-bit platforms. 95 Array<Klass*>* _resolved_klasses; 96 97 u2 _major_version; // major version number of class file 98 u2 _minor_version; // minor version number of class file 99 100 // Constant pool index to the utf8 entry of the Generic signature, 101 // or 0 if none. 102 u2 _generic_signature_index; 103 // Constant pool index to the utf8 entry for the name of source file 104 // containing this klass, 0 if not specified. 105 u2 _source_file_name_index; 106 107 enum { 108 _has_preresolution = 1, // Flags 109 _on_stack = 2, 110 _is_shared = 4, 111 _has_dynamic_constant = 8 112 }; 113 114 u2 _flags; // old fashioned bit twiddling 115 116 int _length; // number of elements in the array 117 118 union { 119 // set for CDS to restore resolved references 120 int _resolved_reference_length; 121 // keeps version number for redefined classes (used in backtrace) 122 int _version; 123 } _saved; 124 125 void set_tags(Array<u1>* tags) { _tags = tags; } 126 void tag_at_put(int cp_index, jbyte t) { tags()->at_put(cp_index, t); } 127 void release_tag_at_put(int cp_index, jbyte t) { tags()->release_at_put(cp_index, t); } 128 129 u1* tag_addr_at(int cp_index) const { return tags()->adr_at(cp_index); } 130 131 void set_operands(Array<u2>* operands) { _operands = operands; } 132 133 u2 flags() const { return _flags; } 134 void set_flags(u2 f) { _flags = f; } 135 136 private: 137 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); } 138 139 intptr_t* obj_at_addr(int cp_index) const { 140 assert(is_within_bounds(cp_index), "index out of bounds"); 141 return (intptr_t*) &base()[cp_index]; 142 } 143 144 jint* int_at_addr(int cp_index) const { 145 assert(is_within_bounds(cp_index), "index out of bounds"); 146 return (jint*) &base()[cp_index]; 147 } 148 149 jlong* long_at_addr(int cp_index) const { 150 assert(is_within_bounds(cp_index), "index out of bounds"); 151 return (jlong*) &base()[cp_index]; 152 } 153 154 jfloat* float_at_addr(int cp_index) const { 155 assert(is_within_bounds(cp_index), "index out of bounds"); 156 return (jfloat*) &base()[cp_index]; 157 } 158 159 jdouble* double_at_addr(int cp_index) const { 160 assert(is_within_bounds(cp_index), "index out of bounds"); 161 return (jdouble*) &base()[cp_index]; 162 } 163 164 ConstantPool(Array<u1>* tags); 165 ConstantPool(); 166 public: 167 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS); 168 169 virtual bool is_constantPool() const { return true; } 170 171 Array<u1>* tags() const { return _tags; } 172 Array<u2>* operands() const { return _operands; } 173 174 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; } 175 void set_has_preresolution() { 176 assert(!is_shared(), "should never be called on shared ConstantPools"); 177 _flags |= _has_preresolution; 178 } 179 180 // minor and major version numbers of class file 181 u2 major_version() const { return _major_version; } 182 void set_major_version(u2 major_version) { _major_version = major_version; } 183 u2 minor_version() const { return _minor_version; } 184 void set_minor_version(u2 minor_version) { _minor_version = minor_version; } 185 186 // generics support 187 Symbol* generic_signature() const { 188 return (_generic_signature_index == 0) ? 189 nullptr : symbol_at(_generic_signature_index); 190 } 191 u2 generic_signature_index() const { return _generic_signature_index; } 192 void set_generic_signature_index(u2 sig_index) { _generic_signature_index = sig_index; } 193 194 // source file name 195 Symbol* source_file_name() const { 196 return (_source_file_name_index == 0) ? 197 nullptr : symbol_at(_source_file_name_index); 198 } 199 u2 source_file_name_index() const { return _source_file_name_index; } 200 void set_source_file_name_index(u2 sourcefile_index) { _source_file_name_index = sourcefile_index; } 201 202 void copy_fields(const ConstantPool* orig); 203 204 // Redefine classes support. If a method referring to this constant pool 205 // is on the executing stack, or as a handle in vm code, this constant pool 206 // can't be removed from the set of previous versions saved in the instance 207 // class. 208 bool on_stack() const; 209 bool is_maybe_on_stack() const; 210 void set_on_stack(const bool value); 211 212 // Faster than MetaspaceObj::is_shared() - used by set_on_stack() 213 bool is_shared() const { return (_flags & _is_shared) != 0; } 214 215 bool has_dynamic_constant() const { return (_flags & _has_dynamic_constant) != 0; } 216 void set_has_dynamic_constant() { _flags |= _has_dynamic_constant; } 217 218 // Klass holding pool 219 InstanceKlass* pool_holder() const { return _pool_holder; } 220 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; } 221 InstanceKlass** pool_holder_addr() { return &_pool_holder; } 222 223 // Interpreter runtime support 224 ConstantPoolCache* cache() const { return _cache; } 225 void set_cache(ConstantPoolCache* cache){ _cache = cache; } 226 227 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 228 virtual MetaspaceObj::Type type() const { return ConstantPoolType; } 229 230 // Create object cache in the constant pool 231 void initialize_resolved_references(ClassLoaderData* loader_data, 232 const intStack& reference_map, 233 int constant_pool_map_length, 234 TRAPS); 235 236 // resolved strings, methodHandles and callsite objects from the constant pool 237 objArrayOop resolved_references() const; 238 objArrayOop resolved_references_or_null() const; 239 oop resolved_reference_at(int obj_index) const; 240 oop set_resolved_reference_at(int index, oop new_value); 241 242 // mapping resolved object array indexes to cp indexes and back. 243 int object_to_cp_index(int index) { return reference_map()->at(index); } 244 int cp_to_object_index(int index); 245 246 void set_resolved_klasses(Array<Klass*>* rk) { _resolved_klasses = rk; } 247 Array<Klass*>* resolved_klasses() const { return _resolved_klasses; } 248 void allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS); 249 void initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS); 250 251 // Invokedynamic indexes. 252 // They must look completely different from normal indexes. 253 // The main reason is that byte swapping is sometimes done on normal indexes. 254 // Finally, it is helpful for debugging to tell the two apart. 255 static bool is_invokedynamic_index(int i) { return (i < 0); } 256 static int decode_invokedynamic_index(int i) { assert(is_invokedynamic_index(i), ""); return ~i; } 257 static int encode_invokedynamic_index(int i) { assert(!is_invokedynamic_index(i), ""); return ~i; } 258 259 // Given the per-instruction index of an indy instruction, report the 260 // main constant pool entry for its bootstrap specifier. 261 // From there, uncached_name/signature_ref_at will get the name/type. 262 inline u2 invokedynamic_bootstrap_ref_index_at(int indy_index) const; 263 264 // Assembly code support 265 static ByteSize tags_offset() { return byte_offset_of(ConstantPool, _tags); } 266 static ByteSize cache_offset() { return byte_offset_of(ConstantPool, _cache); } 267 static ByteSize pool_holder_offset() { return byte_offset_of(ConstantPool, _pool_holder); } 268 static ByteSize resolved_klasses_offset() { return byte_offset_of(ConstantPool, _resolved_klasses); } 269 270 // Storing constants 271 272 // For temporary use while constructing constant pool 273 void klass_index_at_put(int cp_index, int name_index) { 274 tag_at_put(cp_index, JVM_CONSTANT_ClassIndex); 275 *int_at_addr(cp_index) = name_index; 276 } 277 278 // Hidden class support: 279 void klass_at_put(int class_index, Klass* k); 280 281 void unresolved_klass_at_put(int cp_index, int name_index, int resolved_klass_index) { 282 release_tag_at_put(cp_index, JVM_CONSTANT_UnresolvedClass); 283 284 assert((name_index & 0xffff0000) == 0, "must be"); 285 assert((resolved_klass_index & 0xffff0000) == 0, "must be"); 286 *int_at_addr(cp_index) = 287 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index); 288 } 289 290 void method_handle_index_at_put(int cp_index, int ref_kind, int ref_index) { 291 tag_at_put(cp_index, JVM_CONSTANT_MethodHandle); 292 *int_at_addr(cp_index) = ((jint) ref_index<<16) | ref_kind; 293 } 294 295 void method_type_index_at_put(int cp_index, int ref_index) { 296 tag_at_put(cp_index, JVM_CONSTANT_MethodType); 297 *int_at_addr(cp_index) = ref_index; 298 } 299 300 void dynamic_constant_at_put(int cp_index, int bsms_attribute_index, int name_and_type_index) { 301 tag_at_put(cp_index, JVM_CONSTANT_Dynamic); 302 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | bsms_attribute_index; 303 } 304 305 void invoke_dynamic_at_put(int cp_index, int bsms_attribute_index, int name_and_type_index) { 306 tag_at_put(cp_index, JVM_CONSTANT_InvokeDynamic); 307 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | bsms_attribute_index; 308 } 309 310 void unresolved_string_at_put(int cp_index, Symbol* s) { 311 assert(s->refcount() != 0, "should have nonzero refcount"); 312 // Note that release_tag_at_put is not needed here because this is called only 313 // when constructing a ConstantPool in a single thread, with no possibility 314 // of concurrent access. 315 tag_at_put(cp_index, JVM_CONSTANT_String); 316 *symbol_at_addr(cp_index) = s; 317 } 318 319 void int_at_put(int cp_index, jint i) { 320 tag_at_put(cp_index, JVM_CONSTANT_Integer); 321 *int_at_addr(cp_index) = i; 322 } 323 324 void long_at_put(int cp_index, jlong l) { 325 tag_at_put(cp_index, JVM_CONSTANT_Long); 326 // *long_at_addr(which) = l; 327 Bytes::put_native_u8((address)long_at_addr(cp_index), *((u8*) &l)); 328 } 329 330 void float_at_put(int cp_index, jfloat f) { 331 tag_at_put(cp_index, JVM_CONSTANT_Float); 332 *float_at_addr(cp_index) = f; 333 } 334 335 void double_at_put(int cp_index, jdouble d) { 336 tag_at_put(cp_index, JVM_CONSTANT_Double); 337 // *double_at_addr(which) = d; 338 // u8 temp = *(u8*) &d; 339 Bytes::put_native_u8((address) double_at_addr(cp_index), *((u8*) &d)); 340 } 341 342 Symbol** symbol_at_addr(int cp_index) const { 343 assert(is_within_bounds(cp_index), "index out of bounds"); 344 return (Symbol**) &base()[cp_index]; 345 } 346 347 void symbol_at_put(int cp_index, Symbol* s) { 348 assert(s->refcount() != 0, "should have nonzero refcount"); 349 tag_at_put(cp_index, JVM_CONSTANT_Utf8); 350 *symbol_at_addr(cp_index) = s; 351 } 352 353 void string_at_put(int obj_index, oop str); 354 355 // For temporary use while constructing constant pool 356 void string_index_at_put(int cp_index, int string_index) { 357 tag_at_put(cp_index, JVM_CONSTANT_StringIndex); 358 *int_at_addr(cp_index) = string_index; 359 } 360 361 void field_at_put(int cp_index, int class_index, int name_and_type_index) { 362 tag_at_put(cp_index, JVM_CONSTANT_Fieldref); 363 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index; 364 } 365 366 void method_at_put(int cp_index, int class_index, int name_and_type_index) { 367 tag_at_put(cp_index, JVM_CONSTANT_Methodref); 368 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index; 369 } 370 371 void interface_method_at_put(int cp_index, int class_index, int name_and_type_index) { 372 tag_at_put(cp_index, JVM_CONSTANT_InterfaceMethodref); 373 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index; // Not so nice 374 } 375 376 void name_and_type_at_put(int cp_index, int name_index, int signature_index) { 377 tag_at_put(cp_index, JVM_CONSTANT_NameAndType); 378 *int_at_addr(cp_index) = ((jint) signature_index<<16) | name_index; // Not so nice 379 } 380 381 // Tag query 382 383 constantTag tag_at(int cp_index) const { return (constantTag)tags()->at_acquire(cp_index); } 384 385 // Fetching constants 386 387 Klass* klass_at(int cp_index, TRAPS) { 388 constantPoolHandle h_this(THREAD, this); 389 return klass_at_impl(h_this, cp_index, THREAD); 390 } 391 392 CPKlassSlot klass_slot_at(int cp_index) const { 393 assert(tag_at(cp_index).is_unresolved_klass() || tag_at(cp_index).is_klass(), 394 "Corrupted constant pool"); 395 int value = *int_at_addr(cp_index); 396 int name_index = extract_high_short_from_int(value); 397 int resolved_klass_index = extract_low_short_from_int(value); 398 return CPKlassSlot(name_index, resolved_klass_index); 399 } 400 401 Symbol* klass_name_at(int cp_index) const; // Returns the name, w/o resolving. 402 int klass_name_index_at(int cp_index) const { 403 return klass_slot_at(cp_index).name_index(); 404 } 405 406 Klass* resolved_klass_at(int cp_index) const; // Used by Compiler 407 408 // RedefineClasses() API support: 409 Symbol* klass_at_noresolve(int cp_index) { return klass_name_at(cp_index); } 410 void temp_unresolved_klass_at_put(int cp_index, int name_index) { 411 // Used only during constant pool merging for class redefinition. The resolved klass index 412 // will be initialized later by a call to initialize_unresolved_klasses(). 413 unresolved_klass_at_put(cp_index, name_index, CPKlassSlot::_temp_resolved_klass_index); 414 } 415 416 jint int_at(int cp_index) const { 417 assert(tag_at(cp_index).is_int(), "Corrupted constant pool"); 418 return *int_at_addr(cp_index); 419 } 420 421 jlong long_at(int cp_index) { 422 assert(tag_at(cp_index).is_long(), "Corrupted constant pool"); 423 // return *long_at_addr(cp_index); 424 u8 tmp = Bytes::get_native_u8((address)&base()[cp_index]); 425 return *((jlong*)&tmp); 426 } 427 428 jfloat float_at(int cp_index) { 429 assert(tag_at(cp_index).is_float(), "Corrupted constant pool"); 430 return *float_at_addr(cp_index); 431 } 432 433 jdouble double_at(int cp_index) { 434 assert(tag_at(cp_index).is_double(), "Corrupted constant pool"); 435 u8 tmp = Bytes::get_native_u8((address)&base()[cp_index]); 436 return *((jdouble*)&tmp); 437 } 438 439 Symbol* symbol_at(int cp_index) const { 440 assert(tag_at(cp_index).is_utf8(), "Corrupted constant pool"); 441 return *symbol_at_addr(cp_index); 442 } 443 444 oop string_at(int cp_index, int obj_index, TRAPS) { 445 constantPoolHandle h_this(THREAD, this); 446 return string_at_impl(h_this, cp_index, obj_index, THREAD); 447 } 448 oop string_at(int cp_index, TRAPS) { 449 int obj_index = cp_to_object_index(cp_index); 450 return string_at(cp_index, obj_index, THREAD); 451 } 452 453 // Version that can be used before string oop array is created. 454 oop uncached_string_at(int cp_index, TRAPS); 455 456 // only called when we are sure a string entry is already resolved (via an 457 // earlier string_at call. 458 oop resolved_string_at(int cp_index) { 459 assert(tag_at(cp_index).is_string(), "Corrupted constant pool"); 460 // Must do an acquire here in case another thread resolved the klass 461 // behind our back, lest we later load stale values thru the oop. 462 // we might want a volatile_obj_at in ObjArrayKlass. 463 int obj_index = cp_to_object_index(cp_index); 464 return resolved_reference_at(obj_index); 465 } 466 467 Symbol* unresolved_string_at(int cp_index) { 468 assert(tag_at(cp_index).is_string(), "Corrupted constant pool"); 469 return *symbol_at_addr(cp_index); 470 } 471 472 // Returns an UTF8 for a CONSTANT_String entry at a given index. 473 // UTF8 char* representation was chosen to avoid conversion of 474 // java_lang_Strings at resolved entries into Symbol*s 475 // or vice versa. 476 char* string_at_noresolve(int cp_index); 477 478 jint name_and_type_at(int cp_index) { 479 assert(tag_at(cp_index).is_name_and_type(), "Corrupted constant pool"); 480 return *int_at_addr(cp_index); 481 } 482 483 int method_handle_ref_kind_at(int cp_index) { 484 assert(tag_at(cp_index).is_method_handle() || 485 tag_at(cp_index).is_method_handle_in_error(), "Corrupted constant pool"); 486 return extract_low_short_from_int(*int_at_addr(cp_index)); // mask out unwanted ref_index bits 487 } 488 int method_handle_index_at(int cp_index) { 489 assert(tag_at(cp_index).is_method_handle() || 490 tag_at(cp_index).is_method_handle_in_error(), "Corrupted constant pool"); 491 return extract_high_short_from_int(*int_at_addr(cp_index)); // shift out unwanted ref_kind bits 492 } 493 int method_type_index_at(int cp_index) { 494 assert(tag_at(cp_index).is_method_type() || 495 tag_at(cp_index).is_method_type_in_error(), "Corrupted constant pool"); 496 return *int_at_addr(cp_index); 497 } 498 499 // Derived queries: 500 Symbol* method_handle_name_ref_at(int cp_index) { 501 int member = method_handle_index_at(cp_index); 502 return uncached_name_ref_at(member); 503 } 504 Symbol* method_handle_signature_ref_at(int cp_index) { 505 int member = method_handle_index_at(cp_index); 506 return uncached_signature_ref_at(member); 507 } 508 u2 method_handle_klass_index_at(int cp_index) { 509 int member = method_handle_index_at(cp_index); 510 return uncached_klass_ref_index_at(member); 511 } 512 Symbol* method_type_signature_at(int cp_index) { 513 int sym = method_type_index_at(cp_index); 514 return symbol_at(sym); 515 } 516 517 u2 bootstrap_name_and_type_ref_index_at(int cp_index) { 518 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool"); 519 return extract_high_short_from_int(*int_at_addr(cp_index)); 520 } 521 u2 bootstrap_methods_attribute_index(int cp_index) { 522 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool"); 523 return extract_low_short_from_int(*int_at_addr(cp_index)); 524 } 525 int bootstrap_operand_base(int cp_index) { 526 int bsms_attribute_index = bootstrap_methods_attribute_index(cp_index); 527 return operand_offset_at(operands(), bsms_attribute_index); 528 } 529 // The first part of the operands array consists of an index into the second part. 530 // Extract a 32-bit index value from the first part. 531 static int operand_offset_at(Array<u2>* operands, int bsms_attribute_index) { 532 int n = (bsms_attribute_index * 2); 533 assert(n >= 0 && n+2 <= operands->length(), "oob"); 534 // The first 32-bit index points to the beginning of the second part 535 // of the operands array. Make sure this index is in the first part. 536 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0), 537 operands->at(1))); 538 assert(second_part == 0 || n+2 <= second_part, "oob (2)"); 539 int offset = build_int_from_shorts(operands->at(n+0), 540 operands->at(n+1)); 541 // The offset itself must point into the second part of the array. 542 assert(offset == 0 || (offset >= second_part && offset <= operands->length()), "oob (3)"); 543 return offset; 544 } 545 static void operand_offset_at_put(Array<u2>* operands, int bsms_attribute_index, int offset) { 546 int n = bsms_attribute_index * 2; 547 assert(n >= 0 && n+2 <= operands->length(), "oob"); 548 operands->at_put(n+0, extract_low_short_from_int(offset)); 549 operands->at_put(n+1, extract_high_short_from_int(offset)); 550 } 551 static int operand_array_length(Array<u2>* operands) { 552 if (operands == nullptr || operands->length() == 0) return 0; 553 int second_part = operand_offset_at(operands, 0); 554 return (second_part / 2); 555 } 556 557 #ifdef ASSERT 558 // operand tuples fit together exactly, end to end 559 static int operand_limit_at(Array<u2>* operands, int bsms_attribute_index) { 560 int nextidx = bsms_attribute_index + 1; 561 if (nextidx == operand_array_length(operands)) 562 return operands->length(); 563 else 564 return operand_offset_at(operands, nextidx); 565 } 566 int bootstrap_operand_limit(int cp_index) { 567 int bsms_attribute_index = bootstrap_methods_attribute_index(cp_index); 568 return operand_limit_at(operands(), bsms_attribute_index); 569 } 570 #endif //ASSERT 571 572 // Layout of InvokeDynamic and Dynamic bootstrap method specifier 573 // data in second part of operands array. This encodes one record in 574 // the BootstrapMethods attribute. The whole specifier also includes 575 // the name and type information from the main constant pool entry. 576 enum { 577 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm 578 _indy_argc_offset = 1, // u2 argc 579 _indy_argv_offset = 2 // u2 argv[argc] 580 }; 581 582 // These functions are used in RedefineClasses for CP merge 583 584 int operand_offset_at(int bsms_attribute_index) { 585 assert(0 <= bsms_attribute_index && 586 bsms_attribute_index < operand_array_length(operands()), 587 "Corrupted CP operands"); 588 return operand_offset_at(operands(), bsms_attribute_index); 589 } 590 u2 operand_bootstrap_method_ref_index_at(int bsms_attribute_index) { 591 int offset = operand_offset_at(bsms_attribute_index); 592 return operands()->at(offset + _indy_bsm_offset); 593 } 594 u2 operand_argument_count_at(int bsms_attribute_index) { 595 int offset = operand_offset_at(bsms_attribute_index); 596 u2 argc = operands()->at(offset + _indy_argc_offset); 597 return argc; 598 } 599 u2 operand_argument_index_at(int bsms_attribute_index, int j) { 600 int offset = operand_offset_at(bsms_attribute_index); 601 return operands()->at(offset + _indy_argv_offset + j); 602 } 603 int operand_next_offset_at(int bsms_attribute_index) { 604 int offset = operand_offset_at(bsms_attribute_index) + _indy_argv_offset 605 + operand_argument_count_at(bsms_attribute_index); 606 return offset; 607 } 608 // Compare a bootstrap specifier data in the operands arrays 609 bool compare_operand_to(int bsms_attribute_index1, const constantPoolHandle& cp2, 610 int bsms_attribute_index2); 611 // Find a bootstrap specifier data in the operands array 612 int find_matching_operand(int bsms_attribute_index, const constantPoolHandle& search_cp, 613 int operands_cur_len); 614 // Resize the operands array with delta_len and delta_size 615 void resize_operands(int delta_len, int delta_size, TRAPS); 616 // Extend the operands array with the length and size of the ext_cp operands 617 void extend_operands(const constantPoolHandle& ext_cp, TRAPS); 618 // Shrink the operands array to a smaller array with new_len length 619 void shrink_operands(int new_len, TRAPS); 620 621 u2 bootstrap_method_ref_index_at(int cp_index) { 622 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool"); 623 int op_base = bootstrap_operand_base(cp_index); 624 return operands()->at(op_base + _indy_bsm_offset); 625 } 626 u2 bootstrap_argument_count_at(int cp_index) { 627 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool"); 628 int op_base = bootstrap_operand_base(cp_index); 629 u2 argc = operands()->at(op_base + _indy_argc_offset); 630 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc; 631 int next_offset = bootstrap_operand_limit(cp_index)); 632 assert(end_offset == next_offset, "matched ending"); 633 return argc; 634 } 635 u2 bootstrap_argument_index_at(int cp_index, int j) { 636 int op_base = bootstrap_operand_base(cp_index); 637 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset)); 638 assert((uint)j < (uint)argc, "oob"); 639 return operands()->at(op_base + _indy_argv_offset + j); 640 } 641 642 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve, 643 // name_and_type_ref_index_at) all expect to be passed indices obtained 644 // directly from the bytecode. 645 // If the indices are meant to refer to fields or methods, they are 646 // actually rewritten indices that point to entries in their respective structures 647 // i.e. ResolvedMethodEntries or ResolvedFieldEntries. 648 // The routine to_cp_index manages the adjustment 649 // of these values back to constant pool indices. 650 651 // There are also "uncached" versions which do not adjust the operand index; see below. 652 653 // Lookup for entries consisting of (klass_index, name_and_type index) 654 Klass* klass_ref_at(int which, Bytecodes::Code code, TRAPS); 655 Symbol* klass_ref_at_noresolve(int which, Bytecodes::Code code); 656 Symbol* name_ref_at(int which, Bytecodes::Code code) { 657 int name_index = name_ref_index_at(name_and_type_ref_index_at(which, code)); 658 return symbol_at(name_index); 659 } 660 Symbol* signature_ref_at(int which, Bytecodes::Code code) { 661 int signature_index = signature_ref_index_at(name_and_type_ref_index_at(which, code)); 662 return symbol_at(signature_index); 663 } 664 665 u2 klass_ref_index_at(int which, Bytecodes::Code code); 666 u2 name_and_type_ref_index_at(int which, Bytecodes::Code code); 667 668 constantTag tag_ref_at(int cp_cache_index, Bytecodes::Code code); 669 670 int to_cp_index(int which, Bytecodes::Code code); 671 672 // Lookup for entries consisting of (name_index, signature_index) 673 u2 name_ref_index_at(int cp_index); // == low-order jshort of name_and_type_at(cp_index) 674 u2 signature_ref_index_at(int cp_index); // == high-order jshort of name_and_type_at(cp_index) 675 676 BasicType basic_type_for_signature_at(int cp_index) const; 677 678 // Resolve string constants (to prevent allocation during compilation) 679 void resolve_string_constants(TRAPS) { 680 constantPoolHandle h_this(THREAD, this); 681 resolve_string_constants_impl(h_this, CHECK); 682 } 683 684 #if INCLUDE_CDS 685 // CDS support 686 objArrayOop prepare_resolved_references_for_archiving() NOT_CDS_JAVA_HEAP_RETURN_(nullptr); 687 void add_dumped_interned_strings() NOT_CDS_JAVA_HEAP_RETURN; 688 bool maybe_archive_resolved_klass_at(int cp_index); 689 void remove_unshareable_info(); 690 void restore_unshareable_info(TRAPS); 691 #endif 692 693 private: 694 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 }; 695 public: 696 697 // Get the tag for a constant, which may involve a constant dynamic 698 constantTag constant_tag_at(int cp_index); 699 // Get the basic type for a constant, which may involve a constant dynamic 700 BasicType basic_type_for_constant_at(int cp_index); 701 702 // Resolve late bound constants. 703 oop resolve_constant_at(int cp_index, TRAPS) { 704 constantPoolHandle h_this(THREAD, this); 705 return resolve_constant_at_impl(h_this, cp_index, _no_index_sentinel, nullptr, THREAD); 706 } 707 708 oop resolve_cached_constant_at(int cache_index, TRAPS) { 709 constantPoolHandle h_this(THREAD, this); 710 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, nullptr, THREAD); 711 } 712 713 oop resolve_possibly_cached_constant_at(int cp_index, TRAPS) { 714 constantPoolHandle h_this(THREAD, this); 715 return resolve_constant_at_impl(h_this, cp_index, _possible_index_sentinel, nullptr, THREAD); 716 } 717 718 oop find_cached_constant_at(int cp_index, bool& found_it, TRAPS) { 719 constantPoolHandle h_this(THREAD, this); 720 return resolve_constant_at_impl(h_this, cp_index, _possible_index_sentinel, &found_it, THREAD); 721 } 722 723 void copy_bootstrap_arguments_at(int cp_index, 724 int start_arg, int end_arg, 725 objArrayHandle info, int pos, 726 bool must_resolve, Handle if_not_available, TRAPS) { 727 constantPoolHandle h_this(THREAD, this); 728 copy_bootstrap_arguments_at_impl(h_this, cp_index, start_arg, end_arg, 729 info, pos, must_resolve, if_not_available, THREAD); 730 } 731 732 // Klass name matches name at offset 733 bool klass_name_at_matches(const InstanceKlass* k, int cp_index); 734 735 // Sizing 736 int length() const { return _length; } 737 void set_length(int length) { _length = length; } 738 739 // Tells whether index is within bounds. 740 bool is_within_bounds(int index) const { 741 return 0 <= index && index < length(); 742 } 743 744 // Sizing (in words) 745 static int header_size() { 746 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize; 747 } 748 static int size(int length) { return align_metadata_size(header_size() + length); } 749 int size() const { return size(length()); } 750 751 // ConstantPools should be stored in the read-only region of CDS archive. 752 static bool is_read_only_by_default() { return true; } 753 754 friend class ClassFileParser; 755 friend class SystemDictionary; 756 757 // Used by CDS. These classes need to access the private ConstantPool() constructor. 758 template <class T> friend class CppVtableTesterA; 759 template <class T> friend class CppVtableTesterB; 760 template <class T> friend class CppVtableCloner; 761 762 // Used by compiler to prevent classloading. 763 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which); 764 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which); 765 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which); 766 static bool has_local_signature_at_if_loaded (const constantPoolHandle& this_cp, int which); 767 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which); 768 769 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the 770 // future by other Java code. These take constant pool indices rather than 771 // constant pool cache indices as do the peer methods above. 772 Symbol* uncached_klass_ref_at_noresolve(int cp_index); 773 Symbol* uncached_name_ref_at(int cp_index) { 774 int name_index = name_ref_index_at(uncached_name_and_type_ref_index_at(cp_index)); 775 return symbol_at(name_index); 776 } 777 Symbol* uncached_signature_ref_at(int cp_index) { 778 int signature_index = signature_ref_index_at(uncached_name_and_type_ref_index_at(cp_index)); 779 return symbol_at(signature_index); 780 } 781 u2 uncached_klass_ref_index_at(int cp_index); 782 u2 uncached_name_and_type_ref_index_at(int cp_index); 783 784 // Sharing 785 int pre_resolve_shared_klasses(TRAPS); 786 787 // Debugging 788 const char* printable_name_at(int cp_index) PRODUCT_RETURN0; 789 790 private: 791 792 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); } 793 Array<u2>* reference_map() const { return (_cache == nullptr) ? nullptr : _cache->reference_map(); } 794 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); } 795 796 // Used while constructing constant pool (only by ClassFileParser) 797 jint klass_index_at(int cp_index) { 798 assert(tag_at(cp_index).is_klass_index(), "Corrupted constant pool"); 799 return *int_at_addr(cp_index); 800 } 801 802 jint string_index_at(int cp_index) { 803 assert(tag_at(cp_index).is_string_index(), "Corrupted constant pool"); 804 return *int_at_addr(cp_index); 805 } 806 807 // Performs the LinkResolver checks 808 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS); 809 810 // Implementation of methods that needs an exposed 'this' pointer, in order to 811 // handle GC while executing the method 812 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int cp_index, TRAPS); 813 static oop string_at_impl(const constantPoolHandle& this_cp, int cp_index, int obj_index, TRAPS); 814 815 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k); 816 817 // Resolve string constants (to prevent allocation during compilation) 818 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS); 819 820 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int cp_index, int cache_index, 821 bool* status_return, TRAPS); 822 static void copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int cp_index, 823 int start_arg, int end_arg, 824 objArrayHandle info, int pos, 825 bool must_resolve, Handle if_not_available, TRAPS); 826 827 // Exception handling 828 static void save_and_throw_exception(const constantPoolHandle& this_cp, int cp_index, constantTag tag, TRAPS); 829 830 public: 831 // Exception handling 832 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS); 833 834 // Merging ConstantPool* support: 835 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2); 836 void copy_cp_to(int start_cpi, int end_cpi, const constantPoolHandle& to_cp, int to_cpi, TRAPS) { 837 constantPoolHandle h_this(THREAD, this); 838 copy_cp_to_impl(h_this, start_cpi, end_cpi, to_cp, to_cpi, THREAD); 839 } 840 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_cpi, int end_cpi, const constantPoolHandle& to_cp, int to_cpi, TRAPS); 841 static void copy_entry_to(const constantPoolHandle& from_cp, int from_cpi, const constantPoolHandle& to_cp, int to_cpi); 842 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS); 843 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp); 844 int version() const { return _saved._version; } 845 void set_version(int version) { _saved._version = version; } 846 void increment_and_save_version(int version) { 847 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow 848 } 849 850 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; } 851 int resolved_reference_length() const { return _saved._resolved_reference_length; } 852 853 // Decrease ref counts of symbols that are in the constant pool 854 // when the holder class is unloaded 855 void unreference_symbols(); 856 857 // Deallocate constant pool for RedefineClasses 858 void deallocate_contents(ClassLoaderData* loader_data); 859 void release_C_heap_structures(); 860 861 // JVMTI access - GetConstantPool, RetransformClasses, ... 862 friend class JvmtiConstantPoolReconstituter; 863 864 private: 865 class SymbolHash: public CHeapObj<mtSymbol> { 866 ResourceHashtable<const Symbol*, u2, 256, AnyObj::C_HEAP, mtSymbol, Symbol::compute_hash> _table; 867 868 public: 869 void add_if_absent(const Symbol* sym, u2 value) { 870 bool created; 871 _table.put_if_absent(sym, value, &created); 872 } 873 874 u2 symbol_to_value(const Symbol* sym) { 875 u2* value = _table.get(sym); 876 return (value == nullptr) ? 0 : *value; 877 } 878 }; // End SymbolHash class 879 880 jint cpool_entry_size(jint idx); 881 jint hash_entries_to(SymbolHash *symmap, SymbolHash *classmap); 882 883 // Copy cpool bytes into byte array. 884 // Returns: 885 // int > 0, count of the raw cpool bytes that have been copied 886 // 0, OutOfMemory error 887 // -1, Internal error 888 int copy_cpool_bytes(int cpool_size, 889 SymbolHash* tbl, 890 unsigned char *bytes); 891 892 public: 893 // Verify 894 void verify_on(outputStream* st); 895 896 // Printing 897 void print_on(outputStream* st) const; 898 void print_value_on(outputStream* st) const; 899 void print_entry_on(int index, outputStream* st); 900 901 const char* internal_name() const { return "{constant pool}"; } 902 903 // ResolvedFieldEntry getters 904 inline ResolvedFieldEntry* resolved_field_entry_at(int field_index); 905 inline int resolved_field_entries_length() const; 906 907 // ResolvedMethodEntry getters 908 inline ResolvedMethodEntry* resolved_method_entry_at(int method_index); 909 inline int resolved_method_entries_length() const; 910 inline oop appendix_if_resolved(int method_index) const; 911 912 // ResolvedIndyEntry getters 913 inline ResolvedIndyEntry* resolved_indy_entry_at(int index); 914 inline int resolved_indy_entries_length() const; 915 inline oop resolved_reference_from_indy(int index) const; 916 inline oop resolved_reference_from_method(int index) const; 917 }; 918 919 #endif // SHARE_OOPS_CONSTANTPOOL_HPP