1 /* 2 * Copyright (c) 1997, 2018, 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 #include "precompiled.hpp" 26 #include "jvm.h" 27 #include "aot/aotLoader.hpp" 28 #include "classfile/classFileParser.hpp" 29 #include "classfile/classFileStream.hpp" 30 #include "classfile/classLoader.hpp" 31 #include "classfile/classLoaderData.inline.hpp" 32 #include "classfile/classLoaderDataGraph.inline.hpp" 33 #include "classfile/classLoaderExt.hpp" 34 #include "classfile/dictionary.hpp" 35 #include "classfile/javaClasses.inline.hpp" 36 #include "classfile/klassFactory.hpp" 37 #include "classfile/loaderConstraints.hpp" 38 #include "classfile/packageEntry.hpp" 39 #include "classfile/placeholders.hpp" 40 #include "classfile/protectionDomainCache.hpp" 41 #include "classfile/resolutionErrors.hpp" 42 #include "classfile/stringTable.hpp" 43 #include "classfile/systemDictionary.hpp" 44 #include "classfile/vmSymbols.hpp" 45 #include "code/codeCache.hpp" 46 #include "compiler/compileBroker.hpp" 47 #include "gc/shared/gcTraceTime.inline.hpp" 48 #include "gc/shared/oopStorage.inline.hpp" 49 #include "interpreter/bytecodeStream.hpp" 50 #include "interpreter/interpreter.hpp" 51 #include "jfr/jfrEvents.hpp" 52 #include "logging/log.hpp" 53 #include "logging/logStream.hpp" 54 #include "memory/filemap.hpp" 55 #include "memory/heapShared.hpp" 56 #include "memory/metaspaceClosure.hpp" 57 #include "memory/oopFactory.hpp" 58 #include "memory/resourceArea.hpp" 59 #include "oops/access.inline.hpp" 60 #include "oops/instanceKlass.hpp" 61 #include "oops/instanceRefKlass.hpp" 62 #include "oops/klass.inline.hpp" 63 #include "oops/method.inline.hpp" 64 #include "oops/methodData.hpp" 65 #include "oops/objArrayKlass.hpp" 66 #include "oops/objArrayOop.inline.hpp" 67 #include "oops/oop.inline.hpp" 68 #include "oops/symbol.hpp" 69 #include "oops/typeArrayKlass.hpp" 70 #include "prims/jvmtiEnvBase.hpp" 71 #include "prims/resolvedMethodTable.hpp" 72 #include "prims/methodHandles.hpp" 73 #include "runtime/arguments.hpp" 74 #include "runtime/arguments_ext.hpp" 75 #include "runtime/biasedLocking.hpp" 76 #include "runtime/fieldType.hpp" 77 #include "runtime/handles.inline.hpp" 78 #include "runtime/java.hpp" 79 #include "runtime/javaCalls.hpp" 80 #include "runtime/mutexLocker.hpp" 81 #include "runtime/orderAccess.hpp" 82 #include "runtime/sharedRuntime.hpp" 83 #include "runtime/signature.hpp" 84 #include "services/classLoadingService.hpp" 85 #include "services/diagnosticCommand.hpp" 86 #include "services/threadService.hpp" 87 #include "utilities/macros.hpp" 88 #if INCLUDE_CDS 89 #include "classfile/systemDictionaryShared.hpp" 90 #endif 91 #if INCLUDE_JVMCI 92 #include "jvmci/jvmciRuntime.hpp" 93 #endif 94 #if INCLUDE_JFR 95 #include "jfr/jfr.hpp" 96 #endif 97 98 PlaceholderTable* SystemDictionary::_placeholders = NULL; 99 Dictionary* SystemDictionary::_shared_dictionary = NULL; 100 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 101 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 102 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 103 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; 104 105 int SystemDictionary::_number_of_modifications = 0; 106 oop SystemDictionary::_system_loader_lock_obj = NULL; 107 108 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 109 = { NULL /*, NULL...*/ }; 110 111 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 112 113 oop SystemDictionary::_java_system_loader = NULL; 114 oop SystemDictionary::_java_platform_loader = NULL; 115 116 bool SystemDictionary::_has_checkPackageAccess = false; 117 118 // Default ProtectionDomainCacheSize value 119 120 const int defaultProtectionDomainCacheSize = 1009; 121 122 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL; 123 124 125 // ---------------------------------------------------------------------------- 126 // Java-level SystemLoader and PlatformLoader 127 128 oop SystemDictionary::java_system_loader() { 129 return _java_system_loader; 130 } 131 132 oop SystemDictionary::java_platform_loader() { 133 return _java_platform_loader; 134 } 135 136 void SystemDictionary::compute_java_loaders(TRAPS) { 137 JavaValue result(T_OBJECT); 138 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); 139 JavaCalls::call_static(&result, 140 class_loader_klass, 141 vmSymbols::getSystemClassLoader_name(), 142 vmSymbols::void_classloader_signature(), 143 CHECK); 144 145 _java_system_loader = (oop)result.get_jobject(); 146 147 JavaCalls::call_static(&result, 148 class_loader_klass, 149 vmSymbols::getPlatformClassLoader_name(), 150 vmSymbols::void_classloader_signature(), 151 CHECK); 152 153 _java_platform_loader = (oop)result.get_jobject(); 154 } 155 156 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) { 157 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 158 return ClassLoaderDataGraph::find_or_create(class_loader); 159 } 160 161 // ---------------------------------------------------------------------------- 162 // Parallel class loading check 163 164 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 165 if (class_loader.is_null()) return true; 166 if (AlwaysLockClassLoader) return false; 167 return java_lang_ClassLoader::parallelCapable(class_loader()); 168 } 169 // ---------------------------------------------------------------------------- 170 // ParallelDefineClass flag does not apply to bootclass loader 171 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 172 if (class_loader.is_null()) return false; 173 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 174 return true; 175 } 176 return false; 177 } 178 179 // Returns true if the passed class loader is the builtin application class loader 180 // or a custom system class loader. A customer system class loader can be 181 // specified via -Djava.system.class.loader. 182 bool SystemDictionary::is_system_class_loader(oop class_loader) { 183 if (class_loader == NULL) { 184 return false; 185 } 186 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 187 oopDesc::equals(class_loader, _java_system_loader)); 188 } 189 190 // Returns true if the passed class loader is the platform class loader. 191 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 192 if (class_loader == NULL) { 193 return false; 194 } 195 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 196 } 197 198 // ---------------------------------------------------------------------------- 199 // Resolving of classes 200 201 // Forwards to resolve_or_null 202 203 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 204 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 205 if (HAS_PENDING_EXCEPTION || klass == NULL) { 206 // can return a null klass 207 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 208 } 209 return klass; 210 } 211 212 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 213 bool throw_error, 214 Klass* klass, TRAPS) { 215 if (HAS_PENDING_EXCEPTION) { 216 // If we have a pending exception we forward it to the caller, unless throw_error is true, 217 // in which case we have to check whether the pending exception is a ClassNotFoundException, 218 // and if so convert it to a NoClassDefFoundError 219 // And chain the original ClassNotFoundException 220 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 221 ResourceMark rm(THREAD); 222 assert(klass == NULL, "Should not have result with exception pending"); 223 Handle e(THREAD, PENDING_EXCEPTION); 224 CLEAR_PENDING_EXCEPTION; 225 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 226 } else { 227 return NULL; 228 } 229 } 230 // Class not found, throw appropriate error or exception depending on value of throw_error 231 if (klass == NULL) { 232 ResourceMark rm(THREAD); 233 if (throw_error) { 234 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 235 } else { 236 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 237 } 238 } 239 return klass; 240 } 241 242 243 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 244 bool throw_error, TRAPS) 245 { 246 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 247 } 248 249 250 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null 251 252 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 253 if (FieldType::is_array(class_name)) { 254 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 255 } else { 256 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD); 257 } 258 } 259 260 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;" 261 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name, 262 Handle class_loader, 263 Handle protection_domain, 264 TRAPS) { 265 assert(class_name != NULL && !FieldType::is_array(class_name), "must be"); 266 if (FieldType::is_obj(class_name)) { 267 ResourceMark rm(THREAD); 268 // Ignore wrapping L and ;. 269 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 270 class_name->utf8_length() - 2, CHECK_NULL); 271 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 272 } else { 273 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 274 } 275 } 276 277 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 278 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 279 } 280 281 // Forwards to resolve_instance_class_or_null 282 283 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 284 Handle class_loader, 285 Handle protection_domain, 286 TRAPS) { 287 assert(FieldType::is_array(class_name), "must be array"); 288 Klass* k = NULL; 289 FieldArrayInfo fd; 290 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 291 // of this call 292 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 293 if (t == T_OBJECT) { 294 // naked oop "k" is OK here -- we assign back into it 295 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 296 class_loader, 297 protection_domain, 298 CHECK_NULL); 299 if (k != NULL) { 300 k = k->array_klass(fd.dimension(), CHECK_NULL); 301 } 302 } else { 303 k = Universe::typeArrayKlassObj(t); 304 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 305 } 306 return k; 307 } 308 309 310 // Must be called for any super-class or super-interface resolution 311 // during class definition to allow class circularity checking 312 // super-interface callers: 313 // parse_interfaces - for defineClass & jvmtiRedefineClasses 314 // super-class callers: 315 // ClassFileParser - for defineClass & jvmtiRedefineClasses 316 // load_shared_class - while loading a class from shared archive 317 // resolve_instance_class_or_null: 318 // via: handle_parallel_super_load 319 // when resolving a class that has an existing placeholder with 320 // a saved superclass [i.e. a defineClass is currently in progress] 321 // if another thread is trying to resolve the class, it must do 322 // super-class checks on its own thread to catch class circularity 323 // This last call is critical in class circularity checking for cases 324 // where classloading is delegated to different threads and the 325 // classloader lock is released. 326 // Take the case: Base->Super->Base 327 // 1. If thread T1 tries to do a defineClass of class Base 328 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 329 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 330 // so it tries to load Super 331 // 3. If we load the class internally, or user classloader uses same thread 332 // loadClassFromxxx or defineClass via parseClassFile Super ... 333 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 334 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 335 // 3.4 calls resolve_super_or_fail Base 336 // 3.5 finds T1,Base -> throws class circularity 337 //OR 4. If T2 tries to resolve Super via defineClass Super ... 338 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 339 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 340 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 341 // 4.4 finds T2, Super -> throws class circularity 342 // Must be called, even if superclass is null, since this is 343 // where the placeholder entry is created which claims this 344 // thread is loading this class/classloader. 345 // Be careful when modifying this code: once you have run 346 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 347 // you need to find_and_remove it before returning. 348 // So be careful to not exit with a CHECK_ macro betweeen these calls. 349 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 350 Symbol* super_name, 351 Handle class_loader, 352 Handle protection_domain, 353 bool is_superclass, 354 TRAPS) { 355 assert(!FieldType::is_array(super_name), "invalid super class name"); 356 #if INCLUDE_CDS 357 if (DumpSharedSpaces) { 358 // Special processing for CDS dump time. 359 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 360 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 361 if (k) { 362 return k; 363 } 364 } 365 #endif // INCLUDE_CDS 366 367 // Double-check, if child class is already loaded, just return super-class,interface 368 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 369 // dictionary. 370 // Make sure there's a placeholder for the *child* before resolving. 371 // Used as a claim that this thread is currently loading superclass/classloader 372 // Used here for ClassCircularity checks and also for heap verification 373 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 374 // Must check ClassCircularity before checking if super class is already loaded. 375 // 376 // We might not already have a placeholder if this child_name was 377 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 378 // the name of the class might not be known until the stream is actually 379 // parsed. 380 // Bugs 4643874, 4715493 381 382 ClassLoaderData* loader_data = class_loader_data(class_loader); 383 Dictionary* dictionary = loader_data->dictionary(); 384 unsigned int d_hash = dictionary->compute_hash(child_name); 385 unsigned int p_hash = placeholders()->compute_hash(child_name); 386 int p_index = placeholders()->hash_to_index(p_hash); 387 // can't throw error holding a lock 388 bool child_already_loaded = false; 389 bool throw_circularity_error = false; 390 { 391 MutexLocker mu(SystemDictionary_lock, THREAD); 392 InstanceKlass* childk = find_class(d_hash, child_name, dictionary); 393 InstanceKlass* quicksuperk; 394 // to support // loading: if child done loading, just return superclass 395 // if super_name, & class_loader don't match: 396 // if initial define, SD update will give LinkageError 397 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 398 // so we don't throw an exception here. 399 // see: nsk redefclass014 & java.lang.instrument Instrument032 400 if ((childk != NULL ) && (is_superclass) && 401 ((quicksuperk = childk->java_super()) != NULL) && 402 ((quicksuperk->name() == super_name) && 403 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) { 404 return quicksuperk; 405 } else { 406 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 407 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 408 throw_circularity_error = true; 409 } 410 } 411 if (!throw_circularity_error) { 412 // Be careful not to exit resolve_super 413 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD); 414 } 415 } 416 if (throw_circularity_error) { 417 ResourceMark rm(THREAD); 418 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 419 } 420 421 // java.lang.Object should have been found above 422 assert(super_name != NULL, "null super class for resolving"); 423 // Resolve the super class or interface, check results on return 424 InstanceKlass* superk = 425 SystemDictionary::resolve_instance_class_or_null_helper(super_name, 426 class_loader, 427 protection_domain, 428 THREAD); 429 430 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 431 // It is no longer necessary to keep the placeholder table alive until update_dictionary 432 // or error. GC used to walk the placeholder table as strong roots. 433 // The instanceKlass is kept alive because the class loader is on the stack, 434 // which keeps the loader_data alive, as well as all instanceKlasses in 435 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 436 { 437 MutexLocker mu(SystemDictionary_lock, THREAD); 438 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 439 SystemDictionary_lock->notify_all(); 440 } 441 if (HAS_PENDING_EXCEPTION || superk == NULL) { 442 // can null superk 443 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD); 444 assert(k == NULL || k == superk, "must be"); 445 if (k == NULL) { 446 superk = NULL; 447 } 448 } 449 450 return superk; 451 } 452 453 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 454 Handle class_loader, 455 Handle protection_domain, 456 TRAPS) { 457 if(!has_checkPackageAccess()) return; 458 459 // Now we have to call back to java to check if the initating class has access 460 JavaValue result(T_VOID); 461 LogTarget(Debug, protectiondomain) lt; 462 if (lt.is_enabled()) { 463 ResourceMark rm; 464 // Print out trace information 465 LogStream ls(lt); 466 ls.print_cr("Checking package access"); 467 if (class_loader() != NULL) { 468 ls.print("class loader: "); 469 class_loader()->print_value_on(&ls); 470 } else { 471 ls.print_cr("class loader: NULL"); 472 } 473 if (protection_domain() != NULL) { 474 ls.print(" protection domain: "); 475 protection_domain()->print_value_on(&ls); 476 } else { 477 ls.print_cr(" protection domain: NULL"); 478 } 479 ls.print(" loading: "); klass->print_value_on(&ls); 480 ls.cr(); 481 } 482 483 // This handle and the class_loader handle passed in keeps this class from 484 // being unloaded through several GC points. 485 // The class_loader handle passed in is the initiating loader. 486 Handle mirror(THREAD, klass->java_mirror()); 487 488 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 489 JavaCalls::call_special(&result, 490 class_loader, 491 system_loader, 492 vmSymbols::checkPackageAccess_name(), 493 vmSymbols::class_protectiondomain_signature(), 494 mirror, 495 protection_domain, 496 THREAD); 497 498 if (HAS_PENDING_EXCEPTION) { 499 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 500 } else { 501 log_debug(protectiondomain)("granted"); 502 } 503 504 if (HAS_PENDING_EXCEPTION) return; 505 506 // If no exception has been thrown, we have validated the protection domain 507 // Insert the protection domain of the initiating class into the set. 508 { 509 ClassLoaderData* loader_data = class_loader_data(class_loader); 510 Dictionary* dictionary = loader_data->dictionary(); 511 512 Symbol* kn = klass->name(); 513 unsigned int d_hash = dictionary->compute_hash(kn); 514 515 MutexLocker mu(SystemDictionary_lock, THREAD); 516 int d_index = dictionary->hash_to_index(d_hash); 517 dictionary->add_protection_domain(d_index, d_hash, klass, 518 protection_domain, THREAD); 519 } 520 } 521 522 // We only get here if this thread finds that another thread 523 // has already claimed the placeholder token for the current operation, 524 // but that other thread either never owned or gave up the 525 // object lock 526 // Waits on SystemDictionary_lock to indicate placeholder table updated 527 // On return, caller must recheck placeholder table state 528 // 529 // We only get here if 530 // 1) custom classLoader, i.e. not bootstrap classloader 531 // 2) custom classLoader has broken the class loader objectLock 532 // so another thread got here in parallel 533 // 534 // lockObject must be held. 535 // Complicated dance due to lock ordering: 536 // Must first release the classloader object lock to 537 // allow initial definer to complete the class definition 538 // and to avoid deadlock 539 // Reclaim classloader lock object with same original recursion count 540 // Must release SystemDictionary_lock after notify, since 541 // class loader lock must be claimed before SystemDictionary_lock 542 // to prevent deadlocks 543 // 544 // The notify allows applications that did an untimed wait() on 545 // the classloader object lock to not hang. 546 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 547 assert_lock_strong(SystemDictionary_lock); 548 549 bool calledholdinglock 550 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 551 assert(calledholdinglock,"must hold lock for notify"); 552 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 553 ObjectSynchronizer::notifyall(lockObject, THREAD); 554 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 555 SystemDictionary_lock->wait(); 556 SystemDictionary_lock->unlock(); 557 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 558 SystemDictionary_lock->lock(); 559 } 560 561 // If the class in is in the placeholder table, class loading is in progress 562 // For cases where the application changes threads to load classes, it 563 // is critical to ClassCircularity detection that we try loading 564 // the superclass on the same thread internally, so we do parallel 565 // super class loading here. 566 // This also is critical in cases where the original thread gets stalled 567 // even in non-circularity situations. 568 // Note: must call resolve_super_or_fail even if null super - 569 // to force placeholder entry creation for this class for circularity detection 570 // Caller must check for pending exception 571 // Returns non-null Klass* if other thread has completed load 572 // and we are done, 573 // If return null Klass* and no pending exception, the caller must load the class 574 InstanceKlass* SystemDictionary::handle_parallel_super_load( 575 Symbol* name, Symbol* superclassname, Handle class_loader, 576 Handle protection_domain, Handle lockObject, TRAPS) { 577 578 ClassLoaderData* loader_data = class_loader_data(class_loader); 579 Dictionary* dictionary = loader_data->dictionary(); 580 unsigned int d_hash = dictionary->compute_hash(name); 581 unsigned int p_hash = placeholders()->compute_hash(name); 582 int p_index = placeholders()->hash_to_index(p_hash); 583 584 // superk is not used, resolve_super called for circularity check only 585 // This code is reached in two situations. One if this thread 586 // is loading the same class twice (e.g. ClassCircularity, or 587 // java.lang.instrument). 588 // The second is if another thread started the resolve_super first 589 // and has not yet finished. 590 // In both cases the original caller will clean up the placeholder 591 // entry on error. 592 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 593 superclassname, 594 class_loader, 595 protection_domain, 596 true, 597 CHECK_NULL); 598 599 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 600 // Serial class loaders and bootstrap classloader do wait for superclass loads 601 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 602 MutexLocker mu(SystemDictionary_lock, THREAD); 603 // Check if classloading completed while we were loading superclass or waiting 604 return find_class(d_hash, name, dictionary); 605 } 606 607 // must loop to both handle other placeholder updates 608 // and spurious notifications 609 bool super_load_in_progress = true; 610 PlaceholderEntry* placeholder; 611 while (super_load_in_progress) { 612 MutexLocker mu(SystemDictionary_lock, THREAD); 613 // Check if classloading completed while we were loading superclass or waiting 614 InstanceKlass* check = find_class(d_hash, name, dictionary); 615 if (check != NULL) { 616 // Klass is already loaded, so just return it 617 return check; 618 } else { 619 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 620 if (placeholder && placeholder->super_load_in_progress() ){ 621 // We only get here if the application has released the 622 // classloader lock when another thread was in the middle of loading a 623 // superclass/superinterface for this class, and now 624 // this thread is also trying to load this class. 625 // To minimize surprises, the first thread that started to 626 // load a class should be the one to complete the loading 627 // with the classfile it initially expected. 628 // This logic has the current thread wait once it has done 629 // all the superclass/superinterface loading it can, until 630 // the original thread completes the class loading or fails 631 // If it completes we will use the resulting InstanceKlass 632 // which we will find below in the systemDictionary. 633 // We also get here for parallel bootstrap classloader 634 if (class_loader.is_null()) { 635 SystemDictionary_lock->wait(); 636 } else { 637 double_lock_wait(lockObject, THREAD); 638 } 639 } else { 640 // If not in SD and not in PH, other thread's load must have failed 641 super_load_in_progress = false; 642 } 643 } 644 } 645 return NULL; 646 } 647 648 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) { 649 assert(event != NULL, "invariant"); 650 assert(k != NULL, "invariant"); 651 assert(event->should_commit(), "invariant"); 652 event->set_loadedClass(k); 653 event->set_definingClassLoader(k->class_loader_data()); 654 event->set_initiatingClassLoader(init_cld); 655 event->commit(); 656 } 657 658 659 // Be careful when modifying this code: once you have run 660 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 661 // you need to find_and_remove it before returning. 662 // So be careful to not exit with a CHECK_ macro betweeen these calls. 663 // 664 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;" 665 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 666 Handle class_loader, 667 Handle protection_domain, 668 TRAPS) { 669 assert(name != NULL && !FieldType::is_array(name) && 670 !FieldType::is_obj(name), "invalid class name"); 671 672 EventClassLoad class_load_start_event; 673 674 HandleMark hm(THREAD); 675 676 // Fix for 4474172; see evaluation for more details 677 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 678 ClassLoaderData* loader_data = register_loader(class_loader); 679 Dictionary* dictionary = loader_data->dictionary(); 680 unsigned int d_hash = dictionary->compute_hash(name); 681 682 // Do lookup to see if class already exist and the protection domain 683 // has the right access 684 // This call uses find which checks protection domain already matches 685 // All subsequent calls use find_class, and set has_loaded_class so that 686 // before we return a result we call out to java to check for valid protection domain 687 // to allow returning the Klass* and add it to the pd_set if it is valid 688 { 689 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain); 690 if (probe != NULL) return probe; 691 } 692 693 // Non-bootstrap class loaders will call out to class loader and 694 // define via jvm/jni_DefineClass which will acquire the 695 // class loader object lock to protect against multiple threads 696 // defining the class in parallel by accident. 697 // This lock must be acquired here so the waiter will find 698 // any successful result in the SystemDictionary and not attempt 699 // the define. 700 // ParallelCapable Classloaders and the bootstrap classloader 701 // do not acquire lock here. 702 bool DoObjectLock = true; 703 if (is_parallelCapable(class_loader)) { 704 DoObjectLock = false; 705 } 706 707 unsigned int p_hash = placeholders()->compute_hash(name); 708 int p_index = placeholders()->hash_to_index(p_hash); 709 710 // Class is not in SystemDictionary so we have to do loading. 711 // Make sure we are synchronized on the class loader before we proceed 712 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 713 check_loader_lock_contention(lockObject, THREAD); 714 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 715 716 // Check again (after locking) if class already exist in SystemDictionary 717 bool class_has_been_loaded = false; 718 bool super_load_in_progress = false; 719 bool havesupername = false; 720 InstanceKlass* k = NULL; 721 PlaceholderEntry* placeholder; 722 Symbol* superclassname = NULL; 723 724 assert(THREAD->can_call_java(), 725 "can not load classes with compiler thread: class=%s, classloader=%s", 726 name->as_C_string(), 727 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 728 { 729 MutexLocker mu(SystemDictionary_lock, THREAD); 730 InstanceKlass* check = find_class(d_hash, name, dictionary); 731 if (check != NULL) { 732 // InstanceKlass is already loaded, so just return it 733 class_has_been_loaded = true; 734 k = check; 735 } else { 736 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 737 if (placeholder && placeholder->super_load_in_progress()) { 738 super_load_in_progress = true; 739 if (placeholder->havesupername() == true) { 740 superclassname = placeholder->supername(); 741 havesupername = true; 742 } 743 } 744 } 745 } 746 747 // If the class is in the placeholder table, class loading is in progress 748 if (super_load_in_progress && havesupername==true) { 749 k = handle_parallel_super_load(name, 750 superclassname, 751 class_loader, 752 protection_domain, 753 lockObject, THREAD); 754 if (HAS_PENDING_EXCEPTION) { 755 return NULL; 756 } 757 if (k != NULL) { 758 class_has_been_loaded = true; 759 } 760 } 761 762 bool throw_circularity_error = false; 763 if (!class_has_been_loaded) { 764 bool load_instance_added = false; 765 766 // add placeholder entry to record loading instance class 767 // Five cases: 768 // All cases need to prevent modifying bootclasssearchpath 769 // in parallel with a classload of same classname 770 // Redefineclasses uses existence of the placeholder for the duration 771 // of the class load to prevent concurrent redefinition of not completely 772 // defined classes. 773 // case 1. traditional classloaders that rely on the classloader object lock 774 // - no other need for LOAD_INSTANCE 775 // case 2. traditional classloaders that break the classloader object lock 776 // as a deadlock workaround. Detection of this case requires that 777 // this check is done while holding the classloader object lock, 778 // and that lock is still held when calling classloader's loadClass. 779 // For these classloaders, we ensure that the first requestor 780 // completes the load and other requestors wait for completion. 781 // case 3. Bootstrap classloader - don't own objectLocker 782 // This classloader supports parallelism at the classloader level, 783 // but only allows a single load of a class/classloader pair. 784 // No performance benefit and no deadlock issues. 785 // case 4. parallelCapable user level classloaders - without objectLocker 786 // Allow parallel classloading of a class/classloader pair 787 788 { 789 MutexLocker mu(SystemDictionary_lock, THREAD); 790 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 791 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 792 if (oldprobe) { 793 // only need check_seen_thread once, not on each loop 794 // 6341374 java/lang/Instrument with -Xcomp 795 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 796 throw_circularity_error = true; 797 } else { 798 // case 1: traditional: should never see load_in_progress. 799 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 800 801 // case 3: bootstrap classloader: prevent futile classloading, 802 // wait on first requestor 803 if (class_loader.is_null()) { 804 SystemDictionary_lock->wait(); 805 } else { 806 // case 2: traditional with broken classloader lock. wait on first 807 // requestor. 808 double_lock_wait(lockObject, THREAD); 809 } 810 // Check if classloading completed while we were waiting 811 InstanceKlass* check = find_class(d_hash, name, dictionary); 812 if (check != NULL) { 813 // Klass is already loaded, so just return it 814 k = check; 815 class_has_been_loaded = true; 816 } 817 // check if other thread failed to load and cleaned up 818 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 819 } 820 } 821 } 822 } 823 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 824 // case 4: parallelCapable: allow competing threads to try 825 // LOAD_INSTANCE in parallel 826 827 if (!throw_circularity_error && !class_has_been_loaded) { 828 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 829 load_instance_added = true; 830 // For class loaders that do not acquire the classloader object lock, 831 // if they did not catch another thread holding LOAD_INSTANCE, 832 // need a check analogous to the acquire ObjectLocker/find_class 833 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 834 // one final check if the load has already completed 835 // class loaders holding the ObjectLock shouldn't find the class here 836 InstanceKlass* check = find_class(d_hash, name, dictionary); 837 if (check != NULL) { 838 // Klass is already loaded, so return it after checking/adding protection domain 839 k = check; 840 class_has_been_loaded = true; 841 } 842 } 843 } 844 845 // must throw error outside of owning lock 846 if (throw_circularity_error) { 847 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 848 ResourceMark rm(THREAD); 849 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 850 } 851 852 if (!class_has_been_loaded) { 853 854 // Do actual loading 855 k = load_instance_class(name, class_loader, THREAD); 856 857 // If everything was OK (no exceptions, no null return value), and 858 // class_loader is NOT the defining loader, do a little more bookkeeping. 859 if (!HAS_PENDING_EXCEPTION && k != NULL && 860 !oopDesc::equals(k->class_loader(), class_loader())) { 861 862 check_constraints(d_hash, k, class_loader, false, THREAD); 863 864 // Need to check for a PENDING_EXCEPTION again; check_constraints 865 // can throw and doesn't use the CHECK macro. 866 if (!HAS_PENDING_EXCEPTION) { 867 { // Grabbing the Compile_lock prevents systemDictionary updates 868 // during compilations. 869 MutexLocker mu(Compile_lock, THREAD); 870 update_dictionary(d_hash, p_index, p_hash, 871 k, class_loader, THREAD); 872 } 873 874 if (JvmtiExport::should_post_class_load()) { 875 Thread *thread = THREAD; 876 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 877 JvmtiExport::post_class_load((JavaThread *) thread, k); 878 } 879 } 880 } 881 } // load_instance_class 882 883 if (load_instance_added == true) { 884 // clean up placeholder entries for LOAD_INSTANCE success or error 885 // This brackets the SystemDictionary updates for both defining 886 // and initiating loaders 887 MutexLocker mu(SystemDictionary_lock, THREAD); 888 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 889 SystemDictionary_lock->notify_all(); 890 } 891 } 892 893 if (HAS_PENDING_EXCEPTION || k == NULL) { 894 return NULL; 895 } 896 if (class_load_start_event.should_commit()) { 897 post_class_load_event(&class_load_start_event, k, loader_data); 898 } 899 #ifdef ASSERT 900 { 901 ClassLoaderData* loader_data = k->class_loader_data(); 902 MutexLocker mu(SystemDictionary_lock, THREAD); 903 InstanceKlass* kk = find_class(name, loader_data); 904 assert(kk == k, "should be present in dictionary"); 905 } 906 #endif 907 908 // return if the protection domain in NULL 909 if (protection_domain() == NULL) return k; 910 911 // Check the protection domain has the right access 912 if (dictionary->is_valid_protection_domain(d_hash, name, 913 protection_domain)) { 914 return k; 915 } 916 917 // Verify protection domain. If it fails an exception is thrown 918 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 919 920 return k; 921 } 922 923 924 // This routine does not lock the system dictionary. 925 // 926 // Since readers don't hold a lock, we must make sure that system 927 // dictionary entries are only removed at a safepoint (when only one 928 // thread is running), and are added to in a safe way (all links must 929 // be updated in an MT-safe manner). 930 // 931 // Callers should be aware that an entry could be added just after 932 // _dictionary->bucket(index) is read here, so the caller will not see 933 // the new entry. 934 935 Klass* SystemDictionary::find(Symbol* class_name, 936 Handle class_loader, 937 Handle protection_domain, 938 TRAPS) { 939 940 // The result of this call should be consistent with the result 941 // of the call to resolve_instance_class_or_null(). 942 // See evaluation 6790209 and 4474172 for more details. 943 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 944 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 945 946 if (loader_data == NULL) { 947 // If the ClassLoaderData has not been setup, 948 // then the class loader has no entries in the dictionary. 949 return NULL; 950 } 951 952 Dictionary* dictionary = loader_data->dictionary(); 953 unsigned int d_hash = dictionary->compute_hash(class_name); 954 return dictionary->find(d_hash, class_name, 955 protection_domain); 956 } 957 958 959 // Look for a loaded instance or array klass by name. Do not do any loading. 960 // return NULL in case of error. 961 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 962 Handle class_loader, 963 Handle protection_domain, 964 TRAPS) { 965 Klass* k = NULL; 966 assert(class_name != NULL, "class name must be non NULL"); 967 968 if (FieldType::is_array(class_name)) { 969 // The name refers to an array. Parse the name. 970 // dimension and object_key in FieldArrayInfo are assigned as a 971 // side-effect of this call 972 FieldArrayInfo fd; 973 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 974 if (t != T_OBJECT) { 975 k = Universe::typeArrayKlassObj(t); 976 } else { 977 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 978 } 979 if (k != NULL) { 980 k = k->array_klass_or_null(fd.dimension()); 981 } 982 } else { 983 k = find(class_name, class_loader, protection_domain, THREAD); 984 } 985 return k; 986 } 987 988 // Note: this method is much like resolve_from_stream, but 989 // does not publish the classes via the SystemDictionary. 990 // Handles unsafe_DefineAnonymousClass and redefineclasses 991 // RedefinedClasses do not add to the class hierarchy 992 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 993 Handle class_loader, 994 Handle protection_domain, 995 ClassFileStream* st, 996 const InstanceKlass* unsafe_anonymous_host, 997 GrowableArray<Handle>* cp_patches, 998 TRAPS) { 999 1000 EventClassLoad class_load_start_event; 1001 1002 ClassLoaderData* loader_data; 1003 if (unsafe_anonymous_host != NULL) { 1004 // Create a new CLD for an unsafe anonymous class, that uses the same class loader 1005 // as the unsafe_anonymous_host 1006 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same"); 1007 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader); 1008 } else { 1009 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1010 } 1011 1012 assert(st != NULL, "invariant"); 1013 assert(st->need_verify(), "invariant"); 1014 1015 // Parse stream and create a klass. 1016 // Note that we do this even though this klass might 1017 // already be present in the SystemDictionary, otherwise we would not 1018 // throw potential ClassFormatErrors. 1019 1020 InstanceKlass* k = KlassFactory::create_from_stream(st, 1021 class_name, 1022 loader_data, 1023 protection_domain, 1024 unsafe_anonymous_host, 1025 cp_patches, 1026 CHECK_NULL); 1027 1028 if (unsafe_anonymous_host != NULL && k != NULL) { 1029 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader) 1030 // so that they can be unloaded when the mirror is no longer referenced. 1031 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror())); 1032 1033 { 1034 MutexLocker mu_r(Compile_lock, THREAD); 1035 1036 // Add to class hierarchy, initialize vtables, and do possible 1037 // deoptimizations. 1038 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1039 1040 // But, do not add to dictionary. 1041 1042 // compiled code dependencies need to be validated anyway 1043 notice_modification(); 1044 } 1045 1046 // Rewrite and patch constant pool here. 1047 k->link_class(CHECK_NULL); 1048 if (cp_patches != NULL) { 1049 k->constants()->patch_resolved_references(cp_patches); 1050 } 1051 1052 // If it's anonymous, initialize it now, since nobody else will. 1053 k->eager_initialize(CHECK_NULL); 1054 1055 // notify jvmti 1056 if (JvmtiExport::should_post_class_load()) { 1057 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1058 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1059 } 1060 if (class_load_start_event.should_commit()) { 1061 post_class_load_event(&class_load_start_event, k, loader_data); 1062 } 1063 } 1064 assert(unsafe_anonymous_host != NULL || NULL == cp_patches, 1065 "cp_patches only found with unsafe_anonymous_host"); 1066 1067 return k; 1068 } 1069 1070 // Add a klass to the system from a stream (called by jni_DefineClass and 1071 // JVM_DefineClass). 1072 // Note: class_name can be NULL. In that case we do not know the name of 1073 // the class until we have parsed the stream. 1074 1075 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1076 Handle class_loader, 1077 Handle protection_domain, 1078 ClassFileStream* st, 1079 TRAPS) { 1080 1081 HandleMark hm(THREAD); 1082 1083 // Classloaders that support parallelism, e.g. bootstrap classloader, 1084 // do not acquire lock here 1085 bool DoObjectLock = true; 1086 if (is_parallelCapable(class_loader)) { 1087 DoObjectLock = false; 1088 } 1089 1090 ClassLoaderData* loader_data = register_loader(class_loader); 1091 1092 // Make sure we are synchronized on the class loader before we proceed 1093 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1094 check_loader_lock_contention(lockObject, THREAD); 1095 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1096 1097 assert(st != NULL, "invariant"); 1098 1099 // Parse the stream and create a klass. 1100 // Note that we do this even though this klass might 1101 // already be present in the SystemDictionary, otherwise we would not 1102 // throw potential ClassFormatErrors. 1103 InstanceKlass* k = NULL; 1104 1105 #if INCLUDE_CDS 1106 if (!DumpSharedSpaces) { 1107 k = SystemDictionaryShared::lookup_from_stream(class_name, 1108 class_loader, 1109 protection_domain, 1110 st, 1111 CHECK_NULL); 1112 } 1113 #endif 1114 1115 if (k == NULL) { 1116 if (st->buffer() == NULL) { 1117 return NULL; 1118 } 1119 k = KlassFactory::create_from_stream(st, 1120 class_name, 1121 loader_data, 1122 protection_domain, 1123 NULL, // unsafe_anonymous_host 1124 NULL, // cp_patches 1125 CHECK_NULL); 1126 } 1127 1128 assert(k != NULL, "no klass created"); 1129 Symbol* h_name = k->name(); 1130 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1131 1132 // Add class just loaded 1133 // If a class loader supports parallel classloading handle parallel define requests 1134 // find_or_define_instance_class may return a different InstanceKlass 1135 if (is_parallelCapable(class_loader)) { 1136 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1137 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1138 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1139 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1140 loader_data->add_to_deallocate_list(k); 1141 k = defined_k; 1142 } 1143 } else { 1144 define_instance_class(k, THREAD); 1145 } 1146 1147 // If defining the class throws an exception register 'k' for cleanup. 1148 if (HAS_PENDING_EXCEPTION) { 1149 assert(k != NULL, "Must have an instance klass here!"); 1150 loader_data->add_to_deallocate_list(k); 1151 return NULL; 1152 } 1153 1154 // Make sure we have an entry in the SystemDictionary on success 1155 debug_only( { 1156 MutexLocker mu(SystemDictionary_lock, THREAD); 1157 1158 Klass* check = find_class(h_name, k->class_loader_data()); 1159 assert(check == k, "should be present in the dictionary"); 1160 } ); 1161 1162 return k; 1163 } 1164 1165 #if INCLUDE_CDS 1166 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1167 int number_of_entries) { 1168 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces"); 1169 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1170 "bad shared dictionary size."); 1171 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1172 _shared_dictionary_size, t, number_of_entries, 1173 false /* explicitly set _resizable to false */); 1174 } 1175 1176 1177 // If there is a shared dictionary, then find the entry for the 1178 // given shared system class, if any. 1179 1180 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1181 if (shared_dictionary() != NULL) { 1182 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1183 int d_index = shared_dictionary()->hash_to_index(d_hash); 1184 1185 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1186 } else { 1187 return NULL; 1188 } 1189 } 1190 1191 1192 // Load a class from the shared spaces (found through the shared system 1193 // dictionary). Force the superclass and all interfaces to be loaded. 1194 // Update the class definition to include sibling classes and no 1195 // subclasses (yet). [Classes in the shared space are not part of the 1196 // object hierarchy until loaded.] 1197 1198 InstanceKlass* SystemDictionary::load_shared_class( 1199 Symbol* class_name, Handle class_loader, TRAPS) { 1200 InstanceKlass* ik = find_shared_class(class_name); 1201 // Make sure we only return the boot class for the NULL classloader. 1202 if (ik != NULL && 1203 ik->is_shared_boot_class() && class_loader.is_null()) { 1204 Handle protection_domain; 1205 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1206 } 1207 return NULL; 1208 } 1209 1210 // Check if a shared class can be loaded by the specific classloader: 1211 // 1212 // NULL classloader: 1213 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1214 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1215 // be defined in an unnamed module. 1216 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1217 InstanceKlass* ik, 1218 Handle class_loader, TRAPS) { 1219 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1220 "Cannot use sharing if java.base is patched"); 1221 ResourceMark rm; 1222 int path_index = ik->shared_classpath_index(); 1223 ClassLoaderData* loader_data = class_loader_data(class_loader); 1224 if (path_index < 0) { 1225 // path_index < 0 indicates that the class is intended for a custom loader 1226 // and should not be loaded by boot/platform/app loaders 1227 if (loader_data->is_builtin_class_loader_data()) { 1228 return false; 1229 } else { 1230 return true; 1231 } 1232 } 1233 SharedClassPathEntry* ent = 1234 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); 1235 if (!Universe::is_module_initialized()) { 1236 assert(ent != NULL && ent->is_modules_image(), 1237 "Loading non-bootstrap classes before the module system is initialized"); 1238 assert(class_loader.is_null(), "sanity"); 1239 return true; 1240 } 1241 // Get the pkg_entry from the classloader 1242 TempNewSymbol pkg_name = NULL; 1243 PackageEntry* pkg_entry = NULL; 1244 ModuleEntry* mod_entry = NULL; 1245 const char* pkg_string = NULL; 1246 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1247 if (pkg_name != NULL) { 1248 pkg_string = pkg_name->as_C_string(); 1249 if (loader_data != NULL) { 1250 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1251 } 1252 if (pkg_entry != NULL) { 1253 mod_entry = pkg_entry->module(); 1254 } 1255 } 1256 1257 // If the archived class is from a module that has been patched at runtime, 1258 // the class cannot be loaded from the archive. 1259 if (mod_entry != NULL && mod_entry->is_patched()) { 1260 return false; 1261 } 1262 1263 if (class_loader.is_null()) { 1264 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1265 // The NULL classloader can load archived class originated from the 1266 // "modules" jimage and the -Xbootclasspath/a. For class from the 1267 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1268 // by the NULL classloader. 1269 if (mod_entry != NULL) { 1270 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1271 // ModuleEntry's location agrees with the archived class' origination. 1272 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1273 return true; // Module class from the "module" jimage 1274 } 1275 } 1276 1277 // If the archived class is not from the "module" jimage, the class can be 1278 // loaded by the NULL classloader if 1279 // 1280 // 1. the class is from the unamed package 1281 // 2. or, the class is not from a module defined in the NULL classloader 1282 // 3. or, the class is from an unamed module 1283 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1284 // the class is from the -Xbootclasspath/a 1285 if (pkg_string == NULL || 1286 pkg_entry == NULL || 1287 pkg_entry->in_unnamed_module()) { 1288 assert(mod_entry == NULL || 1289 mod_entry == loader_data->unnamed_module(), 1290 "the unnamed module is not defined in the classloader"); 1291 return true; 1292 } 1293 } 1294 return false; 1295 } else { 1296 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1297 ik, class_loader, pkg_string, pkg_name, 1298 pkg_entry, mod_entry, CHECK_(false)); 1299 return res; 1300 } 1301 } 1302 1303 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1304 Handle class_loader, 1305 Handle protection_domain, TRAPS) { 1306 1307 if (ik != NULL) { 1308 Symbol* class_name = ik->name(); 1309 1310 bool visible = is_shared_class_visible( 1311 class_name, ik, class_loader, CHECK_NULL); 1312 if (!visible) { 1313 return NULL; 1314 } 1315 1316 // Resolve the superclass and interfaces. They must be the same 1317 // as in dump time, because the layout of <ik> depends on 1318 // the specific layout of ik->super() and ik->local_interfaces(). 1319 // 1320 // If unexpected superclass or interfaces are found, we cannot 1321 // load <ik> from the shared archive. 1322 1323 if (ik->super() != NULL) { 1324 Symbol* cn = ik->super()->name(); 1325 Klass *s = resolve_super_or_fail(class_name, cn, 1326 class_loader, protection_domain, true, CHECK_NULL); 1327 if (s != ik->super()) { 1328 // The dynamically resolved super class is not the same as the one we used during dump time, 1329 // so we cannot use ik. 1330 return NULL; 1331 } else { 1332 assert(s->is_shared(), "must be"); 1333 } 1334 } 1335 1336 Array<InstanceKlass*>* interfaces = ik->local_interfaces(); 1337 int num_interfaces = interfaces->length(); 1338 for (int index = 0; index < num_interfaces; index++) { 1339 InstanceKlass* k = interfaces->at(index); 1340 Symbol* name = k->name(); 1341 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1342 if (k != i) { 1343 // The dynamically resolved interface class is not the same as the one we used during dump time, 1344 // so we cannot use ik. 1345 return NULL; 1346 } else { 1347 assert(i->is_shared(), "must be"); 1348 } 1349 } 1350 1351 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1352 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1353 if (new_ik != NULL) { 1354 // The class is changed by CFLH. Return the new class. The shared class is 1355 // not used. 1356 return new_ik; 1357 } 1358 1359 // Adjust methods to recover missing data. They need addresses for 1360 // interpreter entry points and their default native method address 1361 // must be reset. 1362 1363 // Updating methods must be done under a lock so multiple 1364 // threads don't update these in parallel 1365 // 1366 // Shared classes are all currently loaded by either the bootstrap or 1367 // internal parallel class loaders, so this will never cause a deadlock 1368 // on a custom class loader lock. 1369 1370 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1371 { 1372 HandleMark hm(THREAD); 1373 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1374 check_loader_lock_contention(lockObject, THREAD); 1375 ObjectLocker ol(lockObject, THREAD, true); 1376 // prohibited package check assumes all classes loaded from archive call 1377 // restore_unshareable_info which calls ik->set_package() 1378 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1379 } 1380 1381 ik->print_class_load_logging(loader_data, NULL, NULL); 1382 1383 // For boot loader, ensure that GetSystemPackage knows that a class in this 1384 // package was loaded. 1385 if (class_loader.is_null()) { 1386 int path_index = ik->shared_classpath_index(); 1387 ResourceMark rm; 1388 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1389 } 1390 1391 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1392 // Only dump the classes that can be stored into CDS archive 1393 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1394 ResourceMark rm(THREAD); 1395 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1396 classlist_file->flush(); 1397 } 1398 } 1399 1400 // notify a class loaded from shared object 1401 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1402 1403 ik->set_has_passed_fingerprint_check(false); 1404 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1405 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1406 uint64_t cds_fp = ik->get_stored_fingerprint(); 1407 if (aot_fp != 0 && aot_fp == cds_fp) { 1408 // This class matches with a class saved in an AOT library 1409 ik->set_has_passed_fingerprint_check(true); 1410 } else { 1411 ResourceMark rm; 1412 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1413 } 1414 } 1415 } 1416 return ik; 1417 } 1418 1419 void SystemDictionary::clear_invoke_method_table() { 1420 SymbolPropertyEntry* spe = NULL; 1421 for (int index = 0; index < _invoke_method_table->table_size(); index++) { 1422 SymbolPropertyEntry* p = _invoke_method_table->bucket(index); 1423 while (p != NULL) { 1424 spe = p; 1425 p = p->next(); 1426 _invoke_method_table->free_entry(spe); 1427 } 1428 } 1429 } 1430 #endif // INCLUDE_CDS 1431 1432 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1433 1434 if (class_loader.is_null()) { 1435 ResourceMark rm; 1436 PackageEntry* pkg_entry = NULL; 1437 bool search_only_bootloader_append = false; 1438 ClassLoaderData *loader_data = class_loader_data(class_loader); 1439 1440 // Find the package in the boot loader's package entry table. 1441 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1442 if (pkg_name != NULL) { 1443 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1444 } 1445 1446 // Prior to attempting to load the class, enforce the boot loader's 1447 // visibility boundaries. 1448 if (!Universe::is_module_initialized()) { 1449 // During bootstrapping, prior to module initialization, any 1450 // class attempting to be loaded must be checked against the 1451 // java.base packages in the boot loader's PackageEntryTable. 1452 // No class outside of java.base is allowed to be loaded during 1453 // this bootstrapping window. 1454 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1455 // Class is either in the unnamed package or in 1456 // a named package within the unnamed module. Either 1457 // case is outside of java.base, do not attempt to 1458 // load the class post java.base definition. If 1459 // java.base has not been defined, let the class load 1460 // and its package will be checked later by 1461 // ModuleEntryTable::verify_javabase_packages. 1462 if (ModuleEntryTable::javabase_defined()) { 1463 return NULL; 1464 } 1465 } else { 1466 // Check that the class' package is defined within java.base. 1467 ModuleEntry* mod_entry = pkg_entry->module(); 1468 Symbol* mod_entry_name = mod_entry->name(); 1469 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1470 return NULL; 1471 } 1472 } 1473 } else { 1474 // After the module system has been initialized, check if the class' 1475 // package is in a module defined to the boot loader. 1476 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1477 // Class is either in the unnamed package, in a named package 1478 // within a module not defined to the boot loader or in a 1479 // a named package within the unnamed module. In all cases, 1480 // limit visibility to search for the class only in the boot 1481 // loader's append path. 1482 search_only_bootloader_append = true; 1483 } 1484 } 1485 1486 // Prior to bootstrapping's module initialization, never load a class outside 1487 // of the boot loader's module path 1488 assert(Universe::is_module_initialized() || 1489 !search_only_bootloader_append, 1490 "Attempt to load a class outside of boot loader's module path"); 1491 1492 // Search for classes in the CDS archive. 1493 InstanceKlass* k = NULL; 1494 { 1495 #if INCLUDE_CDS 1496 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1497 k = load_shared_class(class_name, class_loader, THREAD); 1498 #endif 1499 } 1500 1501 if (k == NULL) { 1502 // Use VM class loader 1503 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1504 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1505 } 1506 1507 // find_or_define_instance_class may return a different InstanceKlass 1508 if (k != NULL) { 1509 InstanceKlass* defined_k = 1510 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1511 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1512 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1513 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1514 loader_data->add_to_deallocate_list(k); 1515 k = defined_k; 1516 } else if (HAS_PENDING_EXCEPTION) { 1517 loader_data->add_to_deallocate_list(k); 1518 return NULL; 1519 } 1520 } 1521 return k; 1522 } else { 1523 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1524 ResourceMark rm(THREAD); 1525 1526 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1527 JavaThread* jt = (JavaThread*) THREAD; 1528 1529 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1530 ClassLoader::perf_app_classload_selftime(), 1531 ClassLoader::perf_app_classload_count(), 1532 jt->get_thread_stat()->perf_recursion_counts_addr(), 1533 jt->get_thread_stat()->perf_timers_addr(), 1534 PerfClassTraceTime::CLASS_LOAD); 1535 1536 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1537 // Translate to external class name format, i.e., convert '/' chars to '.' 1538 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1539 1540 JavaValue result(T_OBJECT); 1541 1542 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1543 1544 // Call public unsynchronized loadClass(String) directly for all class loaders. 1545 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1546 // acquire a class-name based lock rather than the class loader object lock. 1547 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1548 JavaCalls::call_virtual(&result, 1549 class_loader, 1550 spec_klass, 1551 vmSymbols::loadClass_name(), 1552 vmSymbols::string_class_signature(), 1553 string, 1554 CHECK_NULL); 1555 1556 assert(result.get_type() == T_OBJECT, "just checking"); 1557 oop obj = (oop) result.get_jobject(); 1558 1559 // Primitive classes return null since forName() can not be 1560 // used to obtain any of the Class objects representing primitives or void 1561 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1562 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1563 // For user defined Java class loaders, check that the name returned is 1564 // the same as that requested. This check is done for the bootstrap 1565 // loader when parsing the class file. 1566 if (class_name == k->name()) { 1567 return k; 1568 } 1569 } 1570 // Class is not found or has the wrong name, return NULL 1571 return NULL; 1572 } 1573 } 1574 1575 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) { 1576 EventClassDefine event; 1577 if (event.should_commit()) { 1578 event.set_definedClass(k); 1579 event.set_definingClassLoader(def_cld); 1580 event.commit(); 1581 } 1582 } 1583 1584 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1585 1586 HandleMark hm(THREAD); 1587 ClassLoaderData* loader_data = k->class_loader_data(); 1588 Handle class_loader_h(THREAD, loader_data->class_loader()); 1589 1590 // for bootstrap and other parallel classloaders don't acquire lock, 1591 // use placeholder token 1592 // If a parallelCapable class loader calls define_instance_class instead of 1593 // find_or_define_instance_class to get here, we have a timing 1594 // hole with systemDictionary updates and check_constraints 1595 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1596 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1597 compute_loader_lock_object(class_loader_h, THREAD)), 1598 "define called without lock"); 1599 } 1600 1601 // Check class-loading constraints. Throw exception if violation is detected. 1602 // Grabs and releases SystemDictionary_lock 1603 // The check_constraints/find_class call and update_dictionary sequence 1604 // must be "atomic" for a specific class/classloader pair so we never 1605 // define two different instanceKlasses for that class/classloader pair. 1606 // Existing classloaders will call define_instance_class with the 1607 // classloader lock held 1608 // Parallel classloaders will call find_or_define_instance_class 1609 // which will require a token to perform the define class 1610 Symbol* name_h = k->name(); 1611 Dictionary* dictionary = loader_data->dictionary(); 1612 unsigned int d_hash = dictionary->compute_hash(name_h); 1613 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1614 1615 // Register class just loaded with class loader (placed in Vector) 1616 // Note we do this before updating the dictionary, as this can 1617 // fail with an OutOfMemoryError (if it does, we will *not* put this 1618 // class in the dictionary and will not update the class hierarchy). 1619 // JVMTI FollowReferences needs to find the classes this way. 1620 if (k->class_loader() != NULL) { 1621 methodHandle m(THREAD, Universe::loader_addClass_method()); 1622 JavaValue result(T_VOID); 1623 JavaCallArguments args(class_loader_h); 1624 args.push_oop(Handle(THREAD, k->java_mirror())); 1625 JavaCalls::call(&result, m, &args, CHECK); 1626 } 1627 1628 // Add the new class. We need recompile lock during update of CHA. 1629 { 1630 unsigned int p_hash = placeholders()->compute_hash(name_h); 1631 int p_index = placeholders()->hash_to_index(p_hash); 1632 1633 MutexLocker mu_r(Compile_lock, THREAD); 1634 1635 // Add to class hierarchy, initialize vtables, and do possible 1636 // deoptimizations. 1637 add_to_hierarchy(k, CHECK); // No exception, but can block 1638 1639 // Add to systemDictionary - so other classes can see it. 1640 // Grabs and releases SystemDictionary_lock 1641 update_dictionary(d_hash, p_index, p_hash, 1642 k, class_loader_h, THREAD); 1643 } 1644 k->eager_initialize(THREAD); 1645 1646 // notify jvmti 1647 if (JvmtiExport::should_post_class_load()) { 1648 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1649 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1650 1651 } 1652 post_class_define_event(k, loader_data); 1653 } 1654 1655 // Support parallel classloading 1656 // All parallel class loaders, including bootstrap classloader 1657 // lock a placeholder entry for this class/class_loader pair 1658 // to allow parallel defines of different classes for this class loader 1659 // With AllowParallelDefine flag==true, in case they do not synchronize around 1660 // FindLoadedClass/DefineClass, calls, we check for parallel 1661 // loading for them, wait if a defineClass is in progress 1662 // and return the initial requestor's results 1663 // This flag does not apply to the bootstrap classloader. 1664 // With AllowParallelDefine flag==false, call through to define_instance_class 1665 // which will throw LinkageError: duplicate class definition. 1666 // False is the requested default. 1667 // For better performance, the class loaders should synchronize 1668 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1669 // potentially waste time reading and parsing the bytestream. 1670 // Note: VM callers should ensure consistency of k/class_name,class_loader 1671 // Be careful when modifying this code: once you have run 1672 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1673 // you need to find_and_remove it before returning. 1674 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1675 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1676 InstanceKlass* k, TRAPS) { 1677 1678 Symbol* name_h = k->name(); // passed in class_name may be null 1679 ClassLoaderData* loader_data = class_loader_data(class_loader); 1680 Dictionary* dictionary = loader_data->dictionary(); 1681 1682 unsigned int d_hash = dictionary->compute_hash(name_h); 1683 1684 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1685 unsigned int p_hash = placeholders()->compute_hash(name_h); 1686 int p_index = placeholders()->hash_to_index(p_hash); 1687 PlaceholderEntry* probe; 1688 1689 { 1690 MutexLocker mu(SystemDictionary_lock, THREAD); 1691 // First check if class already defined 1692 if (is_parallelDefine(class_loader)) { 1693 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1694 if (check != NULL) { 1695 return check; 1696 } 1697 } 1698 1699 // Acquire define token for this class/classloader 1700 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1701 // Wait if another thread defining in parallel 1702 // All threads wait - even those that will throw duplicate class: otherwise 1703 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1704 // if other thread has not finished updating dictionary 1705 while (probe->definer() != NULL) { 1706 SystemDictionary_lock->wait(); 1707 } 1708 // Only special cases allow parallel defines and can use other thread's results 1709 // Other cases fall through, and may run into duplicate defines 1710 // caught by finding an entry in the SystemDictionary 1711 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1712 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1713 SystemDictionary_lock->notify_all(); 1714 #ifdef ASSERT 1715 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1716 assert(check != NULL, "definer missed recording success"); 1717 #endif 1718 return probe->instance_klass(); 1719 } else { 1720 // This thread will define the class (even if earlier thread tried and had an error) 1721 probe->set_definer(THREAD); 1722 } 1723 } 1724 1725 define_instance_class(k, THREAD); 1726 1727 Handle linkage_exception = Handle(); // null handle 1728 1729 // definer must notify any waiting threads 1730 { 1731 MutexLocker mu(SystemDictionary_lock, THREAD); 1732 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1733 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1734 if (probe != NULL) { 1735 if (HAS_PENDING_EXCEPTION) { 1736 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1737 CLEAR_PENDING_EXCEPTION; 1738 } else { 1739 probe->set_instance_klass(k); 1740 } 1741 probe->set_definer(NULL); 1742 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1743 SystemDictionary_lock->notify_all(); 1744 } 1745 } 1746 1747 // Can't throw exception while holding lock due to rank ordering 1748 if (linkage_exception() != NULL) { 1749 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1750 } 1751 1752 return k; 1753 } 1754 1755 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1756 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1757 if (class_loader.is_null()) { 1758 return Handle(THREAD, _system_loader_lock_obj); 1759 } else { 1760 return class_loader; 1761 } 1762 } 1763 1764 // This method is added to check how often we have to wait to grab loader 1765 // lock. The results are being recorded in the performance counters defined in 1766 // ClassLoader::_sync_systemLoaderLockContentionRate and 1767 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1768 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1769 if (!UsePerfData) { 1770 return; 1771 } 1772 1773 assert(!loader_lock.is_null(), "NULL lock object"); 1774 1775 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1776 == ObjectSynchronizer::owner_other) { 1777 // contention will likely happen, so increment the corresponding 1778 // contention counter. 1779 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) { 1780 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1781 } else { 1782 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1783 } 1784 } 1785 } 1786 1787 // ---------------------------------------------------------------------------- 1788 // Lookup 1789 1790 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1791 Symbol* class_name, 1792 Dictionary* dictionary) { 1793 assert_locked_or_safepoint(SystemDictionary_lock); 1794 int index = dictionary->hash_to_index(hash); 1795 return dictionary->find_class(index, hash, class_name); 1796 } 1797 1798 1799 // Basic find on classes in the midst of being loaded 1800 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1801 ClassLoaderData* loader_data) { 1802 assert_locked_or_safepoint(SystemDictionary_lock); 1803 unsigned int p_hash = placeholders()->compute_hash(class_name); 1804 int p_index = placeholders()->hash_to_index(p_hash); 1805 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1806 } 1807 1808 1809 // Used for assertions and verification only 1810 // Precalculating the hash and index is an optimization because there are many lookups 1811 // before adding the class. 1812 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1813 assert_locked_or_safepoint(SystemDictionary_lock); 1814 #ifndef ASSERT 1815 guarantee(VerifyBeforeGC || 1816 VerifyDuringGC || 1817 VerifyBeforeExit || 1818 VerifyDuringStartup || 1819 VerifyAfterGC, "too expensive"); 1820 #endif 1821 1822 Dictionary* dictionary = loader_data->dictionary(); 1823 unsigned int d_hash = dictionary->compute_hash(class_name); 1824 return find_class(d_hash, class_name, dictionary); 1825 } 1826 1827 1828 // ---------------------------------------------------------------------------- 1829 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1830 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1831 // before a new class is used. 1832 1833 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1834 assert(k != NULL, "just checking"); 1835 assert_locked_or_safepoint(Compile_lock); 1836 1837 // Link into hierachy. Make sure the vtables are initialized before linking into 1838 k->append_to_sibling_list(); // add to superklass/sibling list 1839 k->process_interfaces(THREAD); // handle all "implements" declarations 1840 k->set_init_state(InstanceKlass::loaded); 1841 // Now flush all code that depended on old class hierarchy. 1842 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1843 // Also, first reinitialize vtable because it may have gotten out of synch 1844 // while the new class wasn't connected to the class hierarchy. 1845 CodeCache::flush_dependents_on(k); 1846 } 1847 1848 // ---------------------------------------------------------------------------- 1849 // GC support 1850 1851 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1852 // Note: anonymous classes are not in the SD. 1853 bool SystemDictionary::do_unloading(GCTimer* gc_timer, 1854 bool do_cleaning) { 1855 1856 bool unloading_occurred; 1857 { 1858 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1859 1860 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1861 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning); 1862 if (unloading_occurred) { 1863 JFR_ONLY(Jfr::on_unloading_classes();) 1864 ClassLoaderDataGraph::clean_module_and_package_info(); 1865 } 1866 } 1867 1868 // TODO: just return if !unloading_occurred. 1869 if (unloading_occurred) { 1870 { 1871 GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer); 1872 // Check if there's work to do in the SymbolTable 1873 SymbolTable::do_check_concurrent_work(); 1874 } 1875 1876 { 1877 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1878 constraints()->purge_loader_constraints(); 1879 resolution_errors()->purge_resolution_errors(); 1880 } 1881 } 1882 1883 { 1884 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1885 // Oops referenced by the protection domain cache table may get unreachable independently 1886 // of the class loader (eg. cached protection domain oops). So we need to 1887 // explicitly unlink them here. 1888 _pd_cache_table->trigger_cleanup(); 1889 } 1890 1891 if (do_cleaning) { 1892 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1893 ResolvedMethodTable::trigger_cleanup(); 1894 } 1895 1896 return unloading_occurred; 1897 } 1898 1899 void SystemDictionary::oops_do(OopClosure* f) { 1900 f->do_oop(&_java_system_loader); 1901 f->do_oop(&_java_platform_loader); 1902 f->do_oop(&_system_loader_lock_obj); 1903 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1904 1905 // Visit extra methods 1906 invoke_method_table()->oops_do(f); 1907 } 1908 1909 // CDS: scan and relocate all classes in the system dictionary. 1910 void SystemDictionary::classes_do(MetaspaceClosure* it) { 1911 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); 1912 } 1913 1914 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1915 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1916 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1917 it->push(well_known_klass_addr((WKID)id)); 1918 } 1919 } 1920 1921 void SystemDictionary::methods_do(void f(Method*)) { 1922 // Walk methods in loaded classes 1923 MutexLocker ml(ClassLoaderDataGraph_lock); 1924 ClassLoaderDataGraph::methods_do(f); 1925 // Walk method handle intrinsics 1926 invoke_method_table()->methods_do(f); 1927 } 1928 1929 class RemoveClassesClosure : public CLDClosure { 1930 public: 1931 void do_cld(ClassLoaderData* cld) { 1932 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 1933 cld->dictionary()->remove_classes_in_error_state(); 1934 } 1935 } 1936 }; 1937 1938 void SystemDictionary::remove_classes_in_error_state() { 1939 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 1940 RemoveClassesClosure rcc; 1941 MutexLocker ml(ClassLoaderDataGraph_lock); 1942 ClassLoaderDataGraph::cld_do(&rcc); 1943 } 1944 1945 // ---------------------------------------------------------------------------- 1946 // Initialization 1947 1948 void SystemDictionary::initialize(TRAPS) { 1949 // Allocate arrays 1950 _placeholders = new PlaceholderTable(_placeholder_table_size); 1951 _number_of_modifications = 0; 1952 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1953 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1954 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1955 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 1956 1957 // Allocate private object used as system class loader lock 1958 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1959 // Initialize basic classes 1960 resolve_well_known_classes(CHECK); 1961 } 1962 1963 // Compact table of directions on the initialization of klasses: 1964 static const short wk_init_info[] = { 1965 #define WK_KLASS_INIT_INFO(name, symbol) \ 1966 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)), 1967 1968 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1969 #undef WK_KLASS_INIT_INFO 1970 0 1971 }; 1972 1973 #ifdef ASSERT 1974 bool SystemDictionary::is_well_known_klass(Symbol* class_name) { 1975 for (int i = 0; ; i++) { 1976 int sid = wk_init_info[i]; 1977 if (sid == 0) { 1978 break; 1979 } 1980 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1981 if (class_name == symbol) { 1982 return true; 1983 } 1984 } 1985 return false; 1986 } 1987 #endif 1988 1989 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) { 1990 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1991 int sid = wk_init_info[id - FIRST_WKID]; 1992 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1993 InstanceKlass** klassp = &_well_known_klasses[id]; 1994 1995 1996 #if INCLUDE_JVMCI 1997 if (id >= FIRST_JVMCI_WKID) { 1998 assert(EnableJVMCI, "resolve JVMCI classes only when EnableJVMCI is true"); 1999 } 2000 #endif 2001 2002 if ((*klassp) == NULL) { 2003 Klass* k = resolve_or_fail(symbol, true, CHECK_0); 2004 (*klassp) = InstanceKlass::cast(k); 2005 } 2006 return ((*klassp) != NULL); 2007 } 2008 2009 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 2010 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 2011 for (int id = (int)start_id; id < (int)limit_id; id++) { 2012 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2013 resolve_wk_klass((WKID)id, CHECK); 2014 } 2015 2016 // move the starting value forward to the limit: 2017 start_id = limit_id; 2018 } 2019 2020 void SystemDictionary::resolve_well_known_classes(TRAPS) { 2021 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once"); 2022 2023 // Create the ModuleEntry for java.base. This call needs to be done here, 2024 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 2025 ClassLoader::classLoader_init2(CHECK); 2026 2027 // Preload commonly used klasses 2028 WKID scan = FIRST_WKID; 2029 // first do Object, then String, Class 2030 #if INCLUDE_CDS 2031 if (UseSharedSpaces) { 2032 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2033 2034 // It's unsafe to access the archived heap regions before they 2035 // are fixed up, so we must do the fixup as early as possible 2036 // before the archived java objects are accessed by functions 2037 // such as java_lang_Class::restore_archived_mirror and 2038 // ConstantPool::restore_unshareable_info (restores the archived 2039 // resolved_references array object). 2040 // 2041 // HeapShared::fixup_mapped_heap_regions() fills the empty 2042 // spaces in the archived heap regions and may use 2043 // SystemDictionary::Object_klass(), so we can do this only after 2044 // Object_klass is resolved. See the above resolve_wk_klasses_through() 2045 // call. No mirror objects are accessed/restored in the above call. 2046 // Mirrors are restored after java.lang.Class is loaded. 2047 HeapShared::fixup_mapped_heap_regions(); 2048 2049 // Initialize the constant pool for the Object_class 2050 Object_klass()->constants()->restore_unshareable_info(CHECK); 2051 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2052 } else 2053 #endif 2054 { 2055 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2056 } 2057 2058 // Calculate offsets for String and Class classes since they are loaded and 2059 // can be used after this point. 2060 java_lang_String::compute_offsets(); 2061 java_lang_Class::compute_offsets(); 2062 2063 // Fixup mirrors for classes loaded before java.lang.Class. 2064 // These calls iterate over the objects currently in the perm gen 2065 // so calling them at this point is matters (not before when there 2066 // are fewer objects and not later after there are more objects 2067 // in the perm gen. 2068 Universe::initialize_basic_type_mirrors(CHECK); 2069 Universe::fixup_mirrors(CHECK); 2070 2071 // do a bunch more: 2072 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2073 2074 // Preload ref klasses and set reference types 2075 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2076 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2077 2078 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2079 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2080 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2081 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2082 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2083 2084 // JSR 292 classes 2085 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2086 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2087 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK); 2088 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK); 2089 WKID last = NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID); 2090 resolve_wk_klasses_until(last, scan, CHECK); 2091 2092 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2093 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2094 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2095 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2096 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2097 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2098 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2099 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2100 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2101 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2102 2103 { // Compute whether we should use checkPackageAccess or NOT 2104 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2105 _has_checkPackageAccess = (method != NULL); 2106 } 2107 2108 if (UseSharedSpaces) { 2109 assert(JvmtiEnvBase::get_phase() <= JVMTI_PHASE_PRIMORDIAL, 2110 "All well known classes must be resolved in JVMTI_PHASE_PRIMORDIAL or before"); 2111 for (int i = FIRST_WKID; i < last; i++) { 2112 InstanceKlass* k = _well_known_klasses[i]; 2113 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook"); 2114 } 2115 } 2116 } 2117 2118 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2119 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2120 BasicType SystemDictionary::box_klass_type(Klass* k) { 2121 assert(k != NULL, ""); 2122 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2123 if (_box_klasses[i] == k) 2124 return (BasicType)i; 2125 } 2126 return T_OBJECT; 2127 } 2128 2129 // Constraints on class loaders. The details of the algorithm can be 2130 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2131 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2132 // that the dictionary needs to maintain a set of contraints that 2133 // must be satisfied by all classes in the dictionary. 2134 // if defining is true, then LinkageError if already in dictionary 2135 // if initiating loader, then ok if InstanceKlass matches existing entry 2136 2137 void SystemDictionary::check_constraints(unsigned int d_hash, 2138 InstanceKlass* k, 2139 Handle class_loader, 2140 bool defining, 2141 TRAPS) { 2142 ResourceMark rm(THREAD); 2143 stringStream ss; 2144 bool throwException = false; 2145 2146 { 2147 Symbol *name = k->name(); 2148 ClassLoaderData *loader_data = class_loader_data(class_loader); 2149 2150 MutexLocker mu(SystemDictionary_lock, THREAD); 2151 2152 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2153 if (check != NULL) { 2154 // If different InstanceKlass - duplicate class definition, 2155 // else - ok, class loaded by a different thread in parallel. 2156 // We should only have found it if it was done loading and ok to use. 2157 // The dictionary only holds instance classes, placeholders 2158 // also hold array classes. 2159 2160 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2161 if ((defining == true) || (k != check)) { 2162 throwException = true; 2163 ss.print("loader %s", loader_data->loader_name_and_id()); 2164 ss.print(" attempted duplicate %s definition for %s. (%s)", 2165 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true)); 2166 } else { 2167 return; 2168 } 2169 } 2170 2171 #ifdef ASSERT 2172 Symbol* ph_check = find_placeholder(name, loader_data); 2173 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2174 #endif 2175 2176 if (throwException == false) { 2177 if (constraints()->check_or_update(k, class_loader, name) == false) { 2178 throwException = true; 2179 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id()); 2180 ss.print(" wants to load %s %s.", 2181 k->external_kind(), k->external_name()); 2182 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); 2183 if (existing_klass->class_loader() != class_loader()) { 2184 ss.print(" A different %s with the same name was previously loaded by %s. (%s)", 2185 existing_klass->external_kind(), 2186 existing_klass->class_loader_data()->loader_name_and_id(), 2187 existing_klass->class_in_module_of_loader(false, true)); 2188 } else { 2189 ss.print(" (%s)", k->class_in_module_of_loader(false, true)); 2190 } 2191 } 2192 } 2193 } 2194 2195 // Throw error now if needed (cannot throw while holding 2196 // SystemDictionary_lock because of rank ordering) 2197 if (throwException == true) { 2198 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); 2199 } 2200 } 2201 2202 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2203 // have been called. 2204 void SystemDictionary::update_dictionary(unsigned int d_hash, 2205 int p_index, unsigned int p_hash, 2206 InstanceKlass* k, 2207 Handle class_loader, 2208 TRAPS) { 2209 // Compile_lock prevents systemDictionary updates during compilations 2210 assert_locked_or_safepoint(Compile_lock); 2211 Symbol* name = k->name(); 2212 ClassLoaderData *loader_data = class_loader_data(class_loader); 2213 2214 { 2215 MutexLocker mu1(SystemDictionary_lock, THREAD); 2216 2217 // See whether biased locking is enabled and if so set it for this 2218 // klass. 2219 // Note that this must be done past the last potential blocking 2220 // point / safepoint. We enable biased locking lazily using a 2221 // VM_Operation to iterate the SystemDictionary and installing the 2222 // biasable mark word into each InstanceKlass's prototype header. 2223 // To avoid race conditions where we accidentally miss enabling the 2224 // optimization for one class in the process of being added to the 2225 // dictionary, we must not safepoint after the test of 2226 // BiasedLocking::enabled(). 2227 if (UseBiasedLocking && BiasedLocking::enabled()) { 2228 // Set biased locking bit for all loaded classes; it will be 2229 // cleared if revocation occurs too often for this type 2230 // NOTE that we must only do this when the class is initally 2231 // defined, not each time it is referenced from a new class loader 2232 if (oopDesc::equals(k->class_loader(), class_loader())) { 2233 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2234 } 2235 } 2236 2237 // Make a new dictionary entry. 2238 Dictionary* dictionary = loader_data->dictionary(); 2239 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2240 if (sd_check == NULL) { 2241 dictionary->add_klass(d_hash, name, k); 2242 notice_modification(); 2243 } 2244 #ifdef ASSERT 2245 sd_check = find_class(d_hash, name, dictionary); 2246 assert (sd_check != NULL, "should have entry in dictionary"); 2247 // Note: there may be a placeholder entry: for circularity testing 2248 // or for parallel defines 2249 #endif 2250 SystemDictionary_lock->notify_all(); 2251 } 2252 } 2253 2254 2255 // Try to find a class name using the loader constraints. The 2256 // loader constraints might know about a class that isn't fully loaded 2257 // yet and these will be ignored. 2258 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2259 Symbol* class_name, Handle class_loader, TRAPS) { 2260 2261 // First see if it has been loaded directly. 2262 // Force the protection domain to be null. (This removes protection checks.) 2263 Handle no_protection_domain; 2264 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2265 no_protection_domain, CHECK_NULL); 2266 if (klass != NULL) 2267 return klass; 2268 2269 // Now look to see if it has been loaded elsewhere, and is subject to 2270 // a loader constraint that would require this loader to return the 2271 // klass that is already loaded. 2272 if (FieldType::is_array(class_name)) { 2273 // For array classes, their Klass*s are not kept in the 2274 // constraint table. The element Klass*s are. 2275 FieldArrayInfo fd; 2276 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2277 if (t != T_OBJECT) { 2278 klass = Universe::typeArrayKlassObj(t); 2279 } else { 2280 MutexLocker mu(SystemDictionary_lock, THREAD); 2281 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2282 } 2283 // If element class already loaded, allocate array klass 2284 if (klass != NULL) { 2285 klass = klass->array_klass_or_null(fd.dimension()); 2286 } 2287 } else { 2288 MutexLocker mu(SystemDictionary_lock, THREAD); 2289 // Non-array classes are easy: simply check the constraint table. 2290 klass = constraints()->find_constrained_klass(class_name, class_loader); 2291 } 2292 2293 return klass; 2294 } 2295 2296 2297 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2298 Handle class_loader1, 2299 Handle class_loader2, 2300 Thread* THREAD) { 2301 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2302 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2303 2304 Symbol* constraint_name = NULL; 2305 // Needs to be in same scope as constraint_name in case a Symbol is created and 2306 // assigned to constraint_name. 2307 FieldArrayInfo fd; 2308 if (!FieldType::is_array(class_name)) { 2309 constraint_name = class_name; 2310 } else { 2311 // For array classes, their Klass*s are not kept in the 2312 // constraint table. The element classes are. 2313 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2314 // primitive types always pass 2315 if (t != T_OBJECT) { 2316 return true; 2317 } else { 2318 constraint_name = fd.object_key(); 2319 } 2320 } 2321 2322 Dictionary* dictionary1 = loader_data1->dictionary(); 2323 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2324 2325 Dictionary* dictionary2 = loader_data2->dictionary(); 2326 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2327 2328 { 2329 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2330 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2331 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2332 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2333 klass2, class_loader2); 2334 } 2335 } 2336 2337 // Add entry to resolution error table to record the error when the first 2338 // attempt to resolve a reference to a class has failed. 2339 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2340 Symbol* error, Symbol* message) { 2341 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2342 int index = resolution_errors()->hash_to_index(hash); 2343 { 2344 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2345 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2346 } 2347 } 2348 2349 // Delete a resolution error for RedefineClasses for a constant pool is going away 2350 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2351 resolution_errors()->delete_entry(pool); 2352 } 2353 2354 // Lookup resolution error table. Returns error if found, otherwise NULL. 2355 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2356 Symbol** message) { 2357 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2358 int index = resolution_errors()->hash_to_index(hash); 2359 { 2360 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2361 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2362 if (entry != NULL) { 2363 *message = entry->message(); 2364 return entry->error(); 2365 } else { 2366 return NULL; 2367 } 2368 } 2369 } 2370 2371 2372 // Signature constraints ensure that callers and callees agree about 2373 // the meaning of type names in their signatures. This routine is the 2374 // intake for constraints. It collects them from several places: 2375 // 2376 // * LinkResolver::resolve_method (if check_access is true) requires 2377 // that the resolving class (the caller) and the defining class of 2378 // the resolved method (the callee) agree on each type in the 2379 // method's signature. 2380 // 2381 // * LinkResolver::resolve_interface_method performs exactly the same 2382 // checks. 2383 // 2384 // * LinkResolver::resolve_field requires that the constant pool 2385 // attempting to link to a field agree with the field's defining 2386 // class about the type of the field signature. 2387 // 2388 // * klassVtable::initialize_vtable requires that, when a class 2389 // overrides a vtable entry allocated by a superclass, that the 2390 // overriding method (i.e., the callee) agree with the superclass 2391 // on each type in the method's signature. 2392 // 2393 // * klassItable::initialize_itable requires that, when a class fills 2394 // in its itables, for each non-abstract method installed in an 2395 // itable, the method (i.e., the callee) agree with the interface 2396 // on each type in the method's signature. 2397 // 2398 // All those methods have a boolean (check_access, checkconstraints) 2399 // which turns off the checks. This is used from specialized contexts 2400 // such as bootstrapping, dumping, and debugging. 2401 // 2402 // No direct constraint is placed between the class and its 2403 // supertypes. Constraints are only placed along linked relations 2404 // between callers and callees. When a method overrides or implements 2405 // an abstract method in a supertype (superclass or interface), the 2406 // constraints are placed as if the supertype were the caller to the 2407 // overriding method. (This works well, since callers to the 2408 // supertype have already established agreement between themselves and 2409 // the supertype.) As a result of all this, a class can disagree with 2410 // its supertype about the meaning of a type name, as long as that 2411 // class neither calls a relevant method of the supertype, nor is 2412 // called (perhaps via an override) from the supertype. 2413 // 2414 // 2415 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2416 // 2417 // Make sure all class components (including arrays) in the given 2418 // signature will be resolved to the same class in both loaders. 2419 // Returns the name of the type that failed a loader constraint check, or 2420 // NULL if no constraint failed. No exception except OOME is thrown. 2421 // Arrays are not added to the loader constraint table, their elements are. 2422 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2423 Handle loader1, Handle loader2, 2424 bool is_method, TRAPS) { 2425 // Nothing to do if loaders are the same. 2426 if (oopDesc::equals(loader1(), loader2())) { 2427 return NULL; 2428 } 2429 2430 SignatureStream sig_strm(signature, is_method); 2431 while (!sig_strm.is_done()) { 2432 if (sig_strm.is_object()) { 2433 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2434 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2435 return sig; 2436 } 2437 } 2438 sig_strm.next(); 2439 } 2440 return NULL; 2441 } 2442 2443 2444 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2445 Symbol* signature, 2446 TRAPS) { 2447 methodHandle empty; 2448 assert(MethodHandles::is_signature_polymorphic(iid) && 2449 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2450 iid != vmIntrinsics::_invokeGeneric, 2451 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2452 2453 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2454 int index = invoke_method_table()->hash_to_index(hash); 2455 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2456 methodHandle m; 2457 if (spe == NULL || spe->method() == NULL) { 2458 spe = NULL; 2459 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2460 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2461 if (!Arguments::is_interpreter_only()) { 2462 // Generate a compiled form of the MH intrinsic. 2463 AdapterHandlerLibrary::create_native_wrapper(m); 2464 // Check if have the compiled code. 2465 if (!m->has_compiled_code()) { 2466 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2467 "Out of space in CodeCache for method handle intrinsic", empty); 2468 } 2469 } 2470 // Now grab the lock. We might have to throw away the new method, 2471 // if a racing thread has managed to install one at the same time. 2472 { 2473 MutexLocker ml(SystemDictionary_lock, THREAD); 2474 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2475 if (spe == NULL) 2476 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2477 if (spe->method() == NULL) 2478 spe->set_method(m()); 2479 } 2480 } 2481 2482 assert(spe != NULL && spe->method() != NULL, ""); 2483 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2484 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2485 "MH intrinsic invariant"); 2486 return spe->method(); 2487 } 2488 2489 // Helper for unpacking the return value from linkMethod and linkCallSite. 2490 static methodHandle unpack_method_and_appendix(Handle mname, 2491 Klass* accessing_klass, 2492 objArrayHandle appendix_box, 2493 Handle* appendix_result, 2494 TRAPS) { 2495 methodHandle empty; 2496 if (mname.not_null()) { 2497 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2498 if (m != NULL) { 2499 oop appendix = appendix_box->obj_at(0); 2500 if (TraceMethodHandles) { 2501 #ifndef PRODUCT 2502 ttyLocker ttyl; 2503 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2504 m->print(); 2505 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2506 tty->cr(); 2507 #endif //PRODUCT 2508 } 2509 (*appendix_result) = Handle(THREAD, appendix); 2510 // the target is stored in the cpCache and if a reference to this 2511 // MemberName is dropped we need a way to make sure the 2512 // class_loader containing this method is kept alive. 2513 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2514 this_key->record_dependency(m->method_holder()); 2515 return methodHandle(THREAD, m); 2516 } 2517 } 2518 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2519 return empty; 2520 } 2521 2522 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2523 Symbol* name, 2524 Symbol* signature, 2525 Klass* accessing_klass, 2526 Handle *appendix_result, 2527 Handle *method_type_result, 2528 TRAPS) { 2529 methodHandle empty; 2530 assert(THREAD->can_call_java() ,""); 2531 Handle method_type = 2532 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2533 2534 int ref_kind = JVM_REF_invokeVirtual; 2535 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2536 Handle name_str (THREAD, name_oop); 2537 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2538 assert(appendix_box->obj_at(0) == NULL, ""); 2539 2540 // This should not happen. JDK code should take care of that. 2541 if (accessing_klass == NULL || method_type.is_null()) { 2542 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2543 } 2544 2545 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2546 JavaCallArguments args; 2547 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2548 args.push_int(ref_kind); 2549 args.push_oop(Handle(THREAD, klass->java_mirror())); 2550 args.push_oop(name_str); 2551 args.push_oop(method_type); 2552 args.push_oop(appendix_box); 2553 JavaValue result(T_OBJECT); 2554 JavaCalls::call_static(&result, 2555 SystemDictionary::MethodHandleNatives_klass(), 2556 vmSymbols::linkMethod_name(), 2557 vmSymbols::linkMethod_signature(), 2558 &args, CHECK_(empty)); 2559 Handle mname(THREAD, (oop) result.get_jobject()); 2560 (*method_type_result) = method_type; 2561 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2562 } 2563 2564 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2565 // We must ensure that all class loaders everywhere will reach this class, for any client. 2566 // This is a safe bet for public classes in java.lang, such as Object and String. 2567 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2568 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2569 static bool is_always_visible_class(oop mirror) { 2570 Klass* klass = java_lang_Class::as_Klass(mirror); 2571 if (klass->is_objArray_klass()) { 2572 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2573 } 2574 if (klass->is_typeArray_klass()) { 2575 return true; // primitive array 2576 } 2577 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2578 return klass->is_public() && 2579 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2580 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2581 } 2582 2583 2584 // Return the Java mirror (java.lang.Class instance) for a single-character 2585 // descriptor. This result, when available, is the same as produced by the 2586 // heavier API point of the same name that takes a Symbol. 2587 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2588 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2589 } 2590 2591 // Find or construct the Java mirror (java.lang.Class instance) for a 2592 // for the given field type signature, as interpreted relative to the 2593 // given class loader. Handles primitives, void, references, arrays, 2594 // and all other reflectable types, except method types. 2595 // N.B. Code in reflection should use this entry point. 2596 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2597 Klass* accessing_klass, 2598 Handle class_loader, 2599 Handle protection_domain, 2600 SignatureStream::FailureMode failure_mode, 2601 TRAPS) { 2602 Handle empty; 2603 2604 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2605 "one or the other, or perhaps neither"); 2606 2607 Symbol* type = signature; 2608 2609 // What we have here must be a valid field descriptor, 2610 // and all valid field descriptors are supported. 2611 // Produce the same java.lang.Class that reflection reports. 2612 if (type->utf8_length() == 1) { 2613 2614 // It's a primitive. (Void has a primitive mirror too.) 2615 char ch = type->char_at(0); 2616 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2617 return Handle(THREAD, find_java_mirror_for_type(ch)); 2618 2619 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2620 2621 // It's a reference type. 2622 if (accessing_klass != NULL) { 2623 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2624 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2625 } 2626 Klass* constant_type_klass; 2627 if (failure_mode == SignatureStream::ReturnNull) { 2628 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2629 CHECK_(empty)); 2630 } else { 2631 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2632 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2633 throw_error, CHECK_(empty)); 2634 } 2635 if (constant_type_klass == NULL) { 2636 return Handle(); // report failure this way 2637 } 2638 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2639 2640 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2641 if (accessing_klass != NULL) { 2642 Klass* sel_klass = constant_type_klass; 2643 bool fold_type_to_class = true; 2644 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2645 fold_type_to_class, CHECK_(empty)); 2646 } 2647 2648 return mirror; 2649 2650 } 2651 2652 // Fall through to an error. 2653 assert(false, "unsupported mirror syntax"); 2654 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2655 } 2656 2657 2658 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2659 // signature, as interpreted relative to the given class loader. 2660 // Because of class loader constraints, all method handle usage must be 2661 // consistent with this loader. 2662 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2663 Klass* accessing_klass, 2664 TRAPS) { 2665 Handle empty; 2666 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2667 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2668 int index = invoke_method_table()->hash_to_index(hash); 2669 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2670 if (spe != NULL && spe->method_type() != NULL) { 2671 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2672 return Handle(THREAD, spe->method_type()); 2673 } else if (!THREAD->can_call_java()) { 2674 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2675 return Handle(); // do not attempt from within compiler, unless it was cached 2676 } 2677 2678 Handle class_loader, protection_domain; 2679 if (accessing_klass != NULL) { 2680 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2681 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2682 } 2683 bool can_be_cached = true; 2684 int npts = ArgumentCount(signature).size(); 2685 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2686 int arg = 0; 2687 Handle rt; // the return type from the signature 2688 ResourceMark rm(THREAD); 2689 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2690 oop mirror = NULL; 2691 if (can_be_cached) { 2692 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2693 mirror = ss.as_java_mirror(Handle(), Handle(), 2694 SignatureStream::ReturnNull, CHECK_(empty)); 2695 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2696 // Fall back to accessing_klass context. 2697 can_be_cached = false; 2698 } 2699 } 2700 if (!can_be_cached) { 2701 // Resolve, throwing a real error if it doesn't work. 2702 mirror = ss.as_java_mirror(class_loader, protection_domain, 2703 SignatureStream::NCDFError, CHECK_(empty)); 2704 } 2705 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string()); 2706 if (ss.at_return_type()) 2707 rt = Handle(THREAD, mirror); 2708 else 2709 pts->obj_at_put(arg++, mirror); 2710 2711 // Check accessibility. 2712 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2713 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2714 mirror = NULL; // safety 2715 // Emulate ConstantPool::verify_constant_pool_resolve. 2716 bool fold_type_to_class = true; 2717 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2718 fold_type_to_class, CHECK_(empty)); 2719 } 2720 } 2721 assert(arg == npts, ""); 2722 2723 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2724 JavaCallArguments args(Handle(THREAD, rt())); 2725 args.push_oop(pts); 2726 JavaValue result(T_OBJECT); 2727 JavaCalls::call_static(&result, 2728 SystemDictionary::MethodHandleNatives_klass(), 2729 vmSymbols::findMethodHandleType_name(), 2730 vmSymbols::findMethodHandleType_signature(), 2731 &args, CHECK_(empty)); 2732 Handle method_type(THREAD, (oop) result.get_jobject()); 2733 2734 if (can_be_cached) { 2735 // We can cache this MethodType inside the JVM. 2736 MutexLocker ml(SystemDictionary_lock, THREAD); 2737 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2738 if (spe == NULL) 2739 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2740 if (spe->method_type() == NULL) { 2741 spe->set_method_type(method_type()); 2742 } 2743 } 2744 2745 // report back to the caller with the MethodType 2746 return method_type; 2747 } 2748 2749 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2750 Klass* accessing_klass, 2751 TRAPS) { 2752 Handle empty; 2753 ResourceMark rm(THREAD); 2754 SignatureStream ss(signature, /*is_method=*/ false); 2755 if (!ss.is_done()) { 2756 Handle class_loader, protection_domain; 2757 if (accessing_klass != NULL) { 2758 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2759 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2760 } 2761 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2762 ss.next(); 2763 if (ss.is_done()) { 2764 return Handle(THREAD, mirror); 2765 } 2766 } 2767 return empty; 2768 } 2769 2770 // Ask Java code to find or construct a method handle constant. 2771 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2772 int ref_kind, //e.g., JVM_REF_invokeVirtual 2773 Klass* callee, 2774 Symbol* name, 2775 Symbol* signature, 2776 TRAPS) { 2777 Handle empty; 2778 if (caller == NULL) { 2779 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2780 } 2781 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2782 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2783 2784 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2785 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2786 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2787 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2788 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2789 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2790 2791 if (ref_kind == JVM_REF_invokeVirtual && 2792 MethodHandles::is_signature_polymorphic_public_name(callee, name)) { 2793 // Skip resolution for public signature polymorphic methods such as 2794 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle 2795 // They require appendix argument which MemberName resolution doesn't handle. 2796 // There's special logic on JDK side to handle them 2797 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2798 } else { 2799 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); 2800 } 2801 2802 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2803 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2804 2805 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2806 JavaCallArguments args; 2807 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2808 args.push_int(ref_kind); 2809 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2810 args.push_oop(name_str); 2811 args.push_oop(type); 2812 JavaValue result(T_OBJECT); 2813 JavaCalls::call_static(&result, 2814 SystemDictionary::MethodHandleNatives_klass(), 2815 vmSymbols::linkMethodHandleConstant_name(), 2816 vmSymbols::linkMethodHandleConstant_signature(), 2817 &args, CHECK_(empty)); 2818 return Handle(THREAD, (oop) result.get_jobject()); 2819 } 2820 2821 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry 2822 Handle SystemDictionary::link_dynamic_constant(Klass* caller, 2823 int condy_index, 2824 Handle bootstrap_specifier, 2825 Symbol* name, 2826 Symbol* type, 2827 TRAPS) { 2828 Handle empty; 2829 Handle bsm, info; 2830 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2831 bsm = bootstrap_specifier; 2832 } else { 2833 assert(bootstrap_specifier->is_objArray(), ""); 2834 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2835 assert(args->length() == 2, ""); 2836 bsm = Handle(THREAD, args->obj_at(0)); 2837 info = Handle(THREAD, args->obj_at(1)); 2838 } 2839 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2840 "caller must supply a valid BSM"); 2841 2842 // This should not happen. JDK code should take care of that. 2843 if (caller == NULL) { 2844 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); 2845 } 2846 2847 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2848 2849 // Resolve the constant type in the context of the caller class 2850 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, 2851 CHECK_(empty)); 2852 2853 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) 2854 JavaCallArguments args; 2855 args.push_oop(Handle(THREAD, caller->java_mirror())); 2856 args.push_int(condy_index); 2857 args.push_oop(bsm); 2858 args.push_oop(constant_name); 2859 args.push_oop(type_mirror); 2860 args.push_oop(info); 2861 JavaValue result(T_OBJECT); 2862 JavaCalls::call_static(&result, 2863 SystemDictionary::MethodHandleNatives_klass(), 2864 vmSymbols::linkDynamicConstant_name(), 2865 vmSymbols::linkDynamicConstant_signature(), 2866 &args, CHECK_(empty)); 2867 2868 return Handle(THREAD, (oop) result.get_jobject()); 2869 } 2870 2871 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2872 // name and signature, as interpreted relative to the given class loader. 2873 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2874 int indy_index, 2875 Handle bootstrap_specifier, 2876 Symbol* name, 2877 Symbol* type, 2878 Handle *appendix_result, 2879 Handle *method_type_result, 2880 TRAPS) { 2881 methodHandle empty; 2882 Handle bsm, info; 2883 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2884 bsm = bootstrap_specifier; 2885 } else { 2886 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2887 assert(args->length() == 2, ""); 2888 bsm = Handle(THREAD, args->obj_at(0)); 2889 info = Handle(THREAD, args->obj_at(1)); 2890 } 2891 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2892 "caller must supply a valid BSM"); 2893 2894 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2895 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2896 2897 // This should not happen. JDK code should take care of that. 2898 if (caller == NULL || method_type.is_null()) { 2899 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2900 } 2901 2902 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2903 assert(appendix_box->obj_at(0) == NULL, ""); 2904 2905 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2906 JavaCallArguments args; 2907 args.push_oop(Handle(THREAD, caller->java_mirror())); 2908 args.push_int(indy_index); 2909 args.push_oop(bsm); 2910 args.push_oop(method_name); 2911 args.push_oop(method_type); 2912 args.push_oop(info); 2913 args.push_oop(appendix_box); 2914 JavaValue result(T_OBJECT); 2915 JavaCalls::call_static(&result, 2916 SystemDictionary::MethodHandleNatives_klass(), 2917 vmSymbols::linkCallSite_name(), 2918 vmSymbols::linkCallSite_signature(), 2919 &args, CHECK_(empty)); 2920 Handle mname(THREAD, (oop) result.get_jobject()); 2921 (*method_type_result) = method_type; 2922 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2923 } 2924 2925 // Protection domain cache table handling 2926 2927 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2928 return _pd_cache_table->get(protection_domain); 2929 } 2930 2931 #if INCLUDE_CDS 2932 void SystemDictionary::reorder_dictionary_for_sharing() { 2933 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); 2934 } 2935 #endif 2936 2937 size_t SystemDictionary::count_bytes_for_buckets() { 2938 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); 2939 } 2940 2941 size_t SystemDictionary::count_bytes_for_table() { 2942 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); 2943 } 2944 2945 void SystemDictionary::copy_buckets(char* top, char* end) { 2946 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2947 } 2948 2949 void SystemDictionary::copy_table(char* top, char* end) { 2950 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2951 } 2952 2953 // ---------------------------------------------------------------------------- 2954 void SystemDictionary::print_shared(outputStream *st) { 2955 shared_dictionary()->print_on(st); 2956 } 2957 2958 void SystemDictionary::print_on(outputStream *st) { 2959 if (shared_dictionary() != NULL) { 2960 st->print_cr("Shared Dictionary"); 2961 shared_dictionary()->print_on(st); 2962 st->cr(); 2963 } 2964 2965 GCMutexLocker mu(SystemDictionary_lock); 2966 2967 ClassLoaderDataGraph::print_dictionary(st); 2968 2969 // Placeholders 2970 placeholders()->print_on(st); 2971 st->cr(); 2972 2973 // loader constraints - print under SD_lock 2974 constraints()->print_on(st); 2975 st->cr(); 2976 2977 _pd_cache_table->print_on(st); 2978 st->cr(); 2979 } 2980 2981 void SystemDictionary::verify() { 2982 guarantee(constraints() != NULL, 2983 "Verify of loader constraints failed"); 2984 guarantee(placeholders()->number_of_entries() >= 0, 2985 "Verify of placeholders failed"); 2986 2987 GCMutexLocker mu(SystemDictionary_lock); 2988 2989 // Verify dictionary 2990 ClassLoaderDataGraph::verify_dictionary(); 2991 2992 placeholders()->verify(); 2993 2994 // Verify constraint table 2995 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2996 constraints()->verify(placeholders()); 2997 2998 _pd_cache_table->verify(); 2999 } 3000 3001 void SystemDictionary::dump(outputStream *st, bool verbose) { 3002 assert_locked_or_safepoint(SystemDictionary_lock); 3003 if (verbose) { 3004 print_on(st); 3005 } else { 3006 if (shared_dictionary() != NULL) { 3007 shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); 3008 } 3009 ClassLoaderDataGraph::print_dictionary_statistics(st); 3010 placeholders()->print_table_statistics(st, "Placeholder Table"); 3011 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 3012 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 3013 } 3014 } 3015 3016 // Utility for dumping dictionaries. 3017 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 3018 DCmdWithParser(output, heap), 3019 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 3020 "BOOLEAN", false, "false") { 3021 _dcmdparser.add_dcmd_option(&_verbose); 3022 } 3023 3024 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 3025 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 3026 _verbose.value()); 3027 VMThread::execute(&dumper); 3028 } 3029 3030 int SystemDictionaryDCmd::num_arguments() { 3031 ResourceMark rm; 3032 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 3033 if (dcmd != NULL) { 3034 DCmdMark mark(dcmd); 3035 return dcmd->_dcmdparser.num_arguments(); 3036 } else { 3037 return 0; 3038 } 3039 } 3040 3041 class CombineDictionariesClosure : public CLDClosure { 3042 private: 3043 Dictionary* _master_dictionary; 3044 public: 3045 CombineDictionariesClosure(Dictionary* master_dictionary) : 3046 _master_dictionary(master_dictionary) {} 3047 void do_cld(ClassLoaderData* cld) { 3048 ResourceMark rm; 3049 if (cld->is_unsafe_anonymous()) { 3050 return; 3051 } 3052 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 3053 for (int i = 0; i < cld->dictionary()->table_size(); ++i) { 3054 Dictionary* curr_dictionary = cld->dictionary(); 3055 DictionaryEntry* p = curr_dictionary->bucket(i); 3056 while (p != NULL) { 3057 Symbol* name = p->instance_klass()->name(); 3058 unsigned int d_hash = _master_dictionary->compute_hash(name); 3059 int d_index = _master_dictionary->hash_to_index(d_hash); 3060 DictionaryEntry* next = p->next(); 3061 if (p->literal()->class_loader_data() != cld) { 3062 // This is an initiating class loader entry; don't use it 3063 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); 3064 curr_dictionary->free_entry(p); 3065 } else { 3066 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); 3067 curr_dictionary->unlink_entry(p); 3068 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. 3069 _master_dictionary->add_entry(d_index, p); 3070 } 3071 p = next; 3072 } 3073 *curr_dictionary->bucket_addr(i) = NULL; 3074 } 3075 } 3076 } 3077 }; 3078 3079 // Combining platform and system loader dictionaries into boot loader dictionary. 3080 // During run time, we only have one shared dictionary. 3081 void SystemDictionary::combine_shared_dictionaries() { 3082 assert(DumpSharedSpaces, "dump time only"); 3083 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); 3084 CombineDictionariesClosure cdc(master_dictionary); 3085 ClassLoaderDataGraph::cld_do(&cdc); 3086 3087 // These tables are no longer valid or necessary. Keeping them around will 3088 // cause SystemDictionary::verify() to fail. Let's empty them. 3089 _placeholders = new PlaceholderTable(_placeholder_table_size); 3090 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 3091 3092 NOT_PRODUCT(SystemDictionary::verify()); 3093 } 3094 3095 void SystemDictionary::initialize_oop_storage() { 3096 _vm_weak_oop_storage = 3097 new OopStorage("VM Weak Oop Handles", 3098 VMWeakAlloc_lock, 3099 VMWeakActive_lock); 3100 } 3101 3102 OopStorage* SystemDictionary::vm_weak_oop_storage() { 3103 assert(_vm_weak_oop_storage != NULL, "Uninitialized"); 3104 return _vm_weak_oop_storage; 3105 }