1 /* 2 * Copyright (c) 1997, 2019, 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/symbolTable.hpp" 44 #include "classfile/systemDictionary.hpp" 45 #include "classfile/vmSymbols.hpp" 46 #include "code/codeCache.hpp" 47 #include "compiler/compileBroker.hpp" 48 #include "gc/shared/gcTraceTime.inline.hpp" 49 #include "gc/shared/oopStorage.inline.hpp" 50 #include "gc/shared/oopStorageSet.hpp" 51 #include "interpreter/bytecodeStream.hpp" 52 #include "interpreter/interpreter.hpp" 53 #include "jfr/jfrEvents.hpp" 54 #include "logging/log.hpp" 55 #include "logging/logStream.hpp" 56 #include "memory/filemap.hpp" 57 #include "memory/heapShared.hpp" 58 #include "memory/metaspaceClosure.hpp" 59 #include "memory/oopFactory.hpp" 60 #include "memory/resourceArea.hpp" 61 #include "memory/universe.hpp" 62 #include "oops/access.inline.hpp" 63 #include "oops/instanceKlass.hpp" 64 #include "oops/instanceRefKlass.hpp" 65 #include "oops/klass.inline.hpp" 66 #include "oops/method.inline.hpp" 67 #include "oops/methodData.hpp" 68 #include "oops/objArrayKlass.hpp" 69 #include "oops/objArrayOop.inline.hpp" 70 #include "oops/oop.inline.hpp" 71 #include "oops/symbol.hpp" 72 #include "oops/typeArrayKlass.hpp" 73 #include "prims/jvmtiExport.hpp" 74 #include "prims/methodHandles.hpp" 75 #include "runtime/arguments.hpp" 76 #include "runtime/biasedLocking.hpp" 77 #include "runtime/fieldType.hpp" 78 #include "runtime/handles.inline.hpp" 79 #include "runtime/java.hpp" 80 #include "runtime/javaCalls.hpp" 81 #include "runtime/mutexLocker.hpp" 82 #include "runtime/orderAccess.hpp" 83 #include "runtime/sharedRuntime.hpp" 84 #include "runtime/signature.hpp" 85 #include "services/classLoadingService.hpp" 86 #include "services/diagnosticCommand.hpp" 87 #include "services/threadService.hpp" 88 #include "utilities/macros.hpp" 89 #if INCLUDE_CDS 90 #include "classfile/systemDictionaryShared.hpp" 91 #endif 92 #if INCLUDE_JFR 93 #include "jfr/jfr.hpp" 94 #endif 95 96 PlaceholderTable* SystemDictionary::_placeholders = NULL; 97 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 98 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 99 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 100 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; 101 102 oop SystemDictionary::_system_loader_lock_obj = NULL; 103 104 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 105 = { NULL /*, NULL...*/ }; 106 107 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 108 109 oop SystemDictionary::_java_system_loader = NULL; 110 oop SystemDictionary::_java_platform_loader = NULL; 111 112 bool SystemDictionary::_has_checkPackageAccess = false; 113 114 // Default ProtectionDomainCacheSize value 115 116 const int defaultProtectionDomainCacheSize = 1009; 117 118 // ---------------------------------------------------------------------------- 119 // Java-level SystemLoader and PlatformLoader 120 121 oop SystemDictionary::java_system_loader() { 122 return _java_system_loader; 123 } 124 125 oop SystemDictionary::java_platform_loader() { 126 return _java_platform_loader; 127 } 128 129 void SystemDictionary::compute_java_loaders(TRAPS) { 130 JavaValue result(T_OBJECT); 131 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); 132 JavaCalls::call_static(&result, 133 class_loader_klass, 134 vmSymbols::getSystemClassLoader_name(), 135 vmSymbols::void_classloader_signature(), 136 CHECK); 137 138 _java_system_loader = (oop)result.get_jobject(); 139 140 JavaCalls::call_static(&result, 141 class_loader_klass, 142 vmSymbols::getPlatformClassLoader_name(), 143 vmSymbols::void_classloader_signature(), 144 CHECK); 145 146 _java_platform_loader = (oop)result.get_jobject(); 147 } 148 149 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) { 150 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 151 return ClassLoaderDataGraph::find_or_create(class_loader); 152 } 153 154 // ---------------------------------------------------------------------------- 155 // Parallel class loading check 156 157 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 158 if (class_loader.is_null()) return true; 159 if (AlwaysLockClassLoader) return false; 160 return java_lang_ClassLoader::parallelCapable(class_loader()); 161 } 162 // ---------------------------------------------------------------------------- 163 // ParallelDefineClass flag does not apply to bootclass loader 164 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 165 if (class_loader.is_null()) return false; 166 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 167 return true; 168 } 169 return false; 170 } 171 172 // Returns true if the passed class loader is the builtin application class loader 173 // or a custom system class loader. A customer system class loader can be 174 // specified via -Djava.system.class.loader. 175 bool SystemDictionary::is_system_class_loader(oop class_loader) { 176 if (class_loader == NULL) { 177 return false; 178 } 179 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 180 class_loader == _java_system_loader); 181 } 182 183 // Returns true if the passed class loader is the platform class loader. 184 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 185 if (class_loader == NULL) { 186 return false; 187 } 188 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 189 } 190 191 // ---------------------------------------------------------------------------- 192 // Resolving of classes 193 194 // Forwards to resolve_or_null 195 196 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 197 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 198 if (HAS_PENDING_EXCEPTION || klass == NULL) { 199 // can return a null klass 200 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 201 } 202 return klass; 203 } 204 205 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 206 bool throw_error, 207 Klass* klass, TRAPS) { 208 if (HAS_PENDING_EXCEPTION) { 209 // If we have a pending exception we forward it to the caller, unless throw_error is true, 210 // in which case we have to check whether the pending exception is a ClassNotFoundException, 211 // and if so convert it to a NoClassDefFoundError 212 // And chain the original ClassNotFoundException 213 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 214 ResourceMark rm(THREAD); 215 assert(klass == NULL, "Should not have result with exception pending"); 216 Handle e(THREAD, PENDING_EXCEPTION); 217 CLEAR_PENDING_EXCEPTION; 218 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 219 } else { 220 return NULL; 221 } 222 } 223 // Class not found, throw appropriate error or exception depending on value of throw_error 224 if (klass == NULL) { 225 ResourceMark rm(THREAD); 226 if (throw_error) { 227 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 228 } else { 229 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 230 } 231 } 232 return klass; 233 } 234 235 236 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 237 bool throw_error, TRAPS) 238 { 239 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 240 } 241 242 243 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null 244 245 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 246 if (FieldType::is_array(class_name)) { 247 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 248 } else { 249 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD); 250 } 251 } 252 253 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;" 254 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name, 255 Handle class_loader, 256 Handle protection_domain, 257 TRAPS) { 258 assert(class_name != NULL && !FieldType::is_array(class_name), "must be"); 259 if (FieldType::is_obj(class_name)) { 260 ResourceMark rm(THREAD); 261 // Ignore wrapping L and ;. 262 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 263 class_name->utf8_length() - 2); 264 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 265 } else { 266 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 267 } 268 } 269 270 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 271 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 272 } 273 274 // Forwards to resolve_instance_class_or_null 275 276 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 277 Handle class_loader, 278 Handle protection_domain, 279 TRAPS) { 280 assert(FieldType::is_array(class_name), "must be array"); 281 Klass* k = NULL; 282 FieldArrayInfo fd; 283 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 284 // of this call 285 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 286 if (t == T_OBJECT) { 287 // naked oop "k" is OK here -- we assign back into it 288 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 289 class_loader, 290 protection_domain, 291 CHECK_NULL); 292 if (k != NULL) { 293 k = k->array_klass(fd.dimension(), CHECK_NULL); 294 } 295 } else { 296 k = Universe::typeArrayKlassObj(t); 297 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 298 } 299 return k; 300 } 301 302 303 // Must be called for any super-class or super-interface resolution 304 // during class definition to allow class circularity checking 305 // super-interface callers: 306 // parse_interfaces - for defineClass & jvmtiRedefineClasses 307 // super-class callers: 308 // ClassFileParser - for defineClass & jvmtiRedefineClasses 309 // load_shared_class - while loading a class from shared archive 310 // resolve_instance_class_or_null: 311 // via: handle_parallel_super_load 312 // when resolving a class that has an existing placeholder with 313 // a saved superclass [i.e. a defineClass is currently in progress] 314 // if another thread is trying to resolve the class, it must do 315 // super-class checks on its own thread to catch class circularity 316 // This last call is critical in class circularity checking for cases 317 // where classloading is delegated to different threads and the 318 // classloader lock is released. 319 // Take the case: Base->Super->Base 320 // 1. If thread T1 tries to do a defineClass of class Base 321 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 322 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 323 // so it tries to load Super 324 // 3. If we load the class internally, or user classloader uses same thread 325 // loadClassFromxxx or defineClass via parseClassFile Super ... 326 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 327 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 328 // 3.4 calls resolve_super_or_fail Base 329 // 3.5 finds T1,Base -> throws class circularity 330 //OR 4. If T2 tries to resolve Super via defineClass Super ... 331 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 332 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 333 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 334 // 4.4 finds T2, Super -> throws class circularity 335 // Must be called, even if superclass is null, since this is 336 // where the placeholder entry is created which claims this 337 // thread is loading this class/classloader. 338 // Be careful when modifying this code: once you have run 339 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 340 // you need to find_and_remove it before returning. 341 // So be careful to not exit with a CHECK_ macro betweeen these calls. 342 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 343 Symbol* super_name, 344 Handle class_loader, 345 Handle protection_domain, 346 bool is_superclass, 347 TRAPS) { 348 assert(!FieldType::is_array(super_name), "invalid super class name"); 349 #if INCLUDE_CDS 350 if (DumpSharedSpaces) { 351 // Special processing for handling UNREGISTERED shared classes. 352 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 353 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 354 if (k) { 355 return k; 356 } 357 } 358 #endif // INCLUDE_CDS 359 360 // Double-check, if child class is already loaded, just return super-class,interface 361 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 362 // dictionary. 363 // Make sure there's a placeholder for the *child* before resolving. 364 // Used as a claim that this thread is currently loading superclass/classloader 365 // Used here for ClassCircularity checks and also for heap verification 366 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 367 // Must check ClassCircularity before checking if super class is already loaded. 368 // 369 // We might not already have a placeholder if this child_name was 370 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 371 // the name of the class might not be known until the stream is actually 372 // parsed. 373 // Bugs 4643874, 4715493 374 375 ClassLoaderData* loader_data = class_loader_data(class_loader); 376 Dictionary* dictionary = loader_data->dictionary(); 377 unsigned int d_hash = dictionary->compute_hash(child_name); 378 unsigned int p_hash = placeholders()->compute_hash(child_name); 379 int p_index = placeholders()->hash_to_index(p_hash); 380 // can't throw error holding a lock 381 bool child_already_loaded = false; 382 bool throw_circularity_error = false; 383 { 384 MutexLocker mu(SystemDictionary_lock, THREAD); 385 InstanceKlass* childk = find_class(d_hash, child_name, dictionary); 386 InstanceKlass* quicksuperk; 387 // to support // loading: if child done loading, just return superclass 388 // if super_name, & class_loader don't match: 389 // if initial define, SD update will give LinkageError 390 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 391 // so we don't throw an exception here. 392 // see: nsk redefclass014 & java.lang.instrument Instrument032 393 if ((childk != NULL ) && (is_superclass) && 394 ((quicksuperk = childk->java_super()) != NULL) && 395 ((quicksuperk->name() == super_name) && 396 (quicksuperk->class_loader() == class_loader()))) { 397 return quicksuperk; 398 } else { 399 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 400 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 401 throw_circularity_error = true; 402 } 403 } 404 if (!throw_circularity_error) { 405 // Be careful not to exit resolve_super 406 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD); 407 } 408 } 409 if (throw_circularity_error) { 410 ResourceMark rm(THREAD); 411 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 412 } 413 414 // java.lang.Object should have been found above 415 assert(super_name != NULL, "null super class for resolving"); 416 // Resolve the super class or interface, check results on return 417 InstanceKlass* superk = 418 SystemDictionary::resolve_instance_class_or_null_helper(super_name, 419 class_loader, 420 protection_domain, 421 THREAD); 422 423 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 424 // It is no longer necessary to keep the placeholder table alive until update_dictionary 425 // or error. GC used to walk the placeholder table as strong roots. 426 // The instanceKlass is kept alive because the class loader is on the stack, 427 // which keeps the loader_data alive, as well as all instanceKlasses in 428 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 429 { 430 MutexLocker mu(SystemDictionary_lock, THREAD); 431 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 432 SystemDictionary_lock->notify_all(); 433 } 434 if (HAS_PENDING_EXCEPTION || superk == NULL) { 435 // can null superk 436 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD); 437 assert(k == NULL || k == superk, "must be"); 438 if (k == NULL) { 439 superk = NULL; 440 } 441 } 442 443 return superk; 444 } 445 446 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 447 Handle class_loader, 448 Handle protection_domain, 449 TRAPS) { 450 if(!has_checkPackageAccess()) return; 451 452 // Now we have to call back to java to check if the initating class has access 453 JavaValue result(T_VOID); 454 LogTarget(Debug, protectiondomain) lt; 455 if (lt.is_enabled()) { 456 ResourceMark rm; 457 // Print out trace information 458 LogStream ls(lt); 459 ls.print_cr("Checking package access"); 460 if (class_loader() != NULL) { 461 ls.print("class loader: "); 462 class_loader()->print_value_on(&ls); 463 } else { 464 ls.print_cr("class loader: NULL"); 465 } 466 if (protection_domain() != NULL) { 467 ls.print(" protection domain: "); 468 protection_domain()->print_value_on(&ls); 469 } else { 470 ls.print_cr(" protection domain: NULL"); 471 } 472 ls.print(" loading: "); klass->print_value_on(&ls); 473 ls.cr(); 474 } 475 476 // This handle and the class_loader handle passed in keeps this class from 477 // being unloaded through several GC points. 478 // The class_loader handle passed in is the initiating loader. 479 Handle mirror(THREAD, klass->java_mirror()); 480 481 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 482 JavaCalls::call_special(&result, 483 class_loader, 484 system_loader, 485 vmSymbols::checkPackageAccess_name(), 486 vmSymbols::class_protectiondomain_signature(), 487 mirror, 488 protection_domain, 489 THREAD); 490 491 if (HAS_PENDING_EXCEPTION) { 492 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 493 } else { 494 log_debug(protectiondomain)("granted"); 495 } 496 497 if (HAS_PENDING_EXCEPTION) return; 498 499 // If no exception has been thrown, we have validated the protection domain 500 // Insert the protection domain of the initiating class into the set. 501 { 502 ClassLoaderData* loader_data = class_loader_data(class_loader); 503 Dictionary* dictionary = loader_data->dictionary(); 504 505 Symbol* kn = klass->name(); 506 unsigned int d_hash = dictionary->compute_hash(kn); 507 508 MutexLocker mu(SystemDictionary_lock, THREAD); 509 int d_index = dictionary->hash_to_index(d_hash); 510 dictionary->add_protection_domain(d_index, d_hash, klass, 511 protection_domain, THREAD); 512 } 513 } 514 515 // We only get here if this thread finds that another thread 516 // has already claimed the placeholder token for the current operation, 517 // but that other thread either never owned or gave up the 518 // object lock 519 // Waits on SystemDictionary_lock to indicate placeholder table updated 520 // On return, caller must recheck placeholder table state 521 // 522 // We only get here if 523 // 1) custom classLoader, i.e. not bootstrap classloader 524 // 2) custom classLoader has broken the class loader objectLock 525 // so another thread got here in parallel 526 // 527 // lockObject must be held. 528 // Complicated dance due to lock ordering: 529 // Must first release the classloader object lock to 530 // allow initial definer to complete the class definition 531 // and to avoid deadlock 532 // Reclaim classloader lock object with same original recursion count 533 // Must release SystemDictionary_lock after notify, since 534 // class loader lock must be claimed before SystemDictionary_lock 535 // to prevent deadlocks 536 // 537 // The notify allows applications that did an untimed wait() on 538 // the classloader object lock to not hang. 539 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 540 assert_lock_strong(SystemDictionary_lock); 541 542 bool calledholdinglock 543 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 544 assert(calledholdinglock,"must hold lock for notify"); 545 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 546 ObjectSynchronizer::notifyall(lockObject, THREAD); 547 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 548 SystemDictionary_lock->wait(); 549 SystemDictionary_lock->unlock(); 550 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 551 SystemDictionary_lock->lock(); 552 } 553 554 // If the class in is in the placeholder table, class loading is in progress 555 // For cases where the application changes threads to load classes, it 556 // is critical to ClassCircularity detection that we try loading 557 // the superclass on the same thread internally, so we do parallel 558 // super class loading here. 559 // This also is critical in cases where the original thread gets stalled 560 // even in non-circularity situations. 561 // Note: must call resolve_super_or_fail even if null super - 562 // to force placeholder entry creation for this class for circularity detection 563 // Caller must check for pending exception 564 // Returns non-null Klass* if other thread has completed load 565 // and we are done, 566 // If return null Klass* and no pending exception, the caller must load the class 567 InstanceKlass* SystemDictionary::handle_parallel_super_load( 568 Symbol* name, Symbol* superclassname, Handle class_loader, 569 Handle protection_domain, Handle lockObject, TRAPS) { 570 571 ClassLoaderData* loader_data = class_loader_data(class_loader); 572 Dictionary* dictionary = loader_data->dictionary(); 573 unsigned int d_hash = dictionary->compute_hash(name); 574 unsigned int p_hash = placeholders()->compute_hash(name); 575 int p_index = placeholders()->hash_to_index(p_hash); 576 577 // superk is not used, resolve_super called for circularity check only 578 // This code is reached in two situations. One if this thread 579 // is loading the same class twice (e.g. ClassCircularity, or 580 // java.lang.instrument). 581 // The second is if another thread started the resolve_super first 582 // and has not yet finished. 583 // In both cases the original caller will clean up the placeholder 584 // entry on error. 585 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 586 superclassname, 587 class_loader, 588 protection_domain, 589 true, 590 CHECK_NULL); 591 592 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 593 // Serial class loaders and bootstrap classloader do wait for superclass loads 594 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 595 MutexLocker mu(SystemDictionary_lock, THREAD); 596 // Check if classloading completed while we were loading superclass or waiting 597 return find_class(d_hash, name, dictionary); 598 } 599 600 // must loop to both handle other placeholder updates 601 // and spurious notifications 602 bool super_load_in_progress = true; 603 PlaceholderEntry* placeholder; 604 while (super_load_in_progress) { 605 MutexLocker mu(SystemDictionary_lock, THREAD); 606 // Check if classloading completed while we were loading superclass or waiting 607 InstanceKlass* check = find_class(d_hash, name, dictionary); 608 if (check != NULL) { 609 // Klass is already loaded, so just return it 610 return check; 611 } else { 612 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 613 if (placeholder && placeholder->super_load_in_progress() ){ 614 // We only get here if the application has released the 615 // classloader lock when another thread was in the middle of loading a 616 // superclass/superinterface for this class, and now 617 // this thread is also trying to load this class. 618 // To minimize surprises, the first thread that started to 619 // load a class should be the one to complete the loading 620 // with the classfile it initially expected. 621 // This logic has the current thread wait once it has done 622 // all the superclass/superinterface loading it can, until 623 // the original thread completes the class loading or fails 624 // If it completes we will use the resulting InstanceKlass 625 // which we will find below in the systemDictionary. 626 // We also get here for parallel bootstrap classloader 627 if (class_loader.is_null()) { 628 SystemDictionary_lock->wait(); 629 } else { 630 double_lock_wait(lockObject, THREAD); 631 } 632 } else { 633 // If not in SD and not in PH, other thread's load must have failed 634 super_load_in_progress = false; 635 } 636 } 637 } 638 return NULL; 639 } 640 641 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) { 642 assert(event != NULL, "invariant"); 643 assert(k != NULL, "invariant"); 644 assert(event->should_commit(), "invariant"); 645 event->set_loadedClass(k); 646 event->set_definingClassLoader(k->class_loader_data()); 647 event->set_initiatingClassLoader(init_cld); 648 event->commit(); 649 } 650 651 652 // Be careful when modifying this code: once you have run 653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 654 // you need to find_and_remove it before returning. 655 // So be careful to not exit with a CHECK_ macro betweeen these calls. 656 // 657 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;" 658 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 659 Handle class_loader, 660 Handle protection_domain, 661 TRAPS) { 662 assert(name != NULL && !FieldType::is_array(name) && 663 !FieldType::is_obj(name), "invalid class name"); 664 665 EventClassLoad class_load_start_event; 666 667 HandleMark hm(THREAD); 668 669 // Fix for 4474172; see evaluation for more details 670 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 671 ClassLoaderData* loader_data = register_loader(class_loader); 672 Dictionary* dictionary = loader_data->dictionary(); 673 unsigned int d_hash = dictionary->compute_hash(name); 674 675 // Do lookup to see if class already exist and the protection domain 676 // has the right access 677 // This call uses find which checks protection domain already matches 678 // All subsequent calls use find_class, and set has_loaded_class so that 679 // before we return a result we call out to java to check for valid protection domain 680 // to allow returning the Klass* and add it to the pd_set if it is valid 681 { 682 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain); 683 if (probe != NULL) return probe; 684 } 685 686 // Non-bootstrap class loaders will call out to class loader and 687 // define via jvm/jni_DefineClass which will acquire the 688 // class loader object lock to protect against multiple threads 689 // defining the class in parallel by accident. 690 // This lock must be acquired here so the waiter will find 691 // any successful result in the SystemDictionary and not attempt 692 // the define. 693 // ParallelCapable Classloaders and the bootstrap classloader 694 // do not acquire lock here. 695 bool DoObjectLock = true; 696 if (is_parallelCapable(class_loader)) { 697 DoObjectLock = false; 698 } 699 700 unsigned int p_hash = placeholders()->compute_hash(name); 701 int p_index = placeholders()->hash_to_index(p_hash); 702 703 // Class is not in SystemDictionary so we have to do loading. 704 // Make sure we are synchronized on the class loader before we proceed 705 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 706 check_loader_lock_contention(lockObject, THREAD); 707 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 708 709 // Check again (after locking) if class already exist in SystemDictionary 710 bool class_has_been_loaded = false; 711 bool super_load_in_progress = false; 712 bool havesupername = false; 713 InstanceKlass* k = NULL; 714 PlaceholderEntry* placeholder; 715 Symbol* superclassname = NULL; 716 717 assert(THREAD->can_call_java(), 718 "can not load classes with compiler thread: class=%s, classloader=%s", 719 name->as_C_string(), 720 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 721 { 722 MutexLocker mu(SystemDictionary_lock, THREAD); 723 InstanceKlass* check = find_class(d_hash, name, dictionary); 724 if (check != NULL) { 725 // InstanceKlass is already loaded, so just return it 726 class_has_been_loaded = true; 727 k = check; 728 } else { 729 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 730 if (placeholder && placeholder->super_load_in_progress()) { 731 super_load_in_progress = true; 732 if (placeholder->havesupername() == true) { 733 superclassname = placeholder->supername(); 734 havesupername = true; 735 } 736 } 737 } 738 } 739 740 // If the class is in the placeholder table, class loading is in progress 741 if (super_load_in_progress && havesupername==true) { 742 k = handle_parallel_super_load(name, 743 superclassname, 744 class_loader, 745 protection_domain, 746 lockObject, THREAD); 747 if (HAS_PENDING_EXCEPTION) { 748 return NULL; 749 } 750 if (k != NULL) { 751 class_has_been_loaded = true; 752 } 753 } 754 755 bool throw_circularity_error = false; 756 if (!class_has_been_loaded) { 757 bool load_instance_added = false; 758 759 // add placeholder entry to record loading instance class 760 // Five cases: 761 // All cases need to prevent modifying bootclasssearchpath 762 // in parallel with a classload of same classname 763 // Redefineclasses uses existence of the placeholder for the duration 764 // of the class load to prevent concurrent redefinition of not completely 765 // defined classes. 766 // case 1. traditional classloaders that rely on the classloader object lock 767 // - no other need for LOAD_INSTANCE 768 // case 2. traditional classloaders that break the classloader object lock 769 // as a deadlock workaround. Detection of this case requires that 770 // this check is done while holding the classloader object lock, 771 // and that lock is still held when calling classloader's loadClass. 772 // For these classloaders, we ensure that the first requestor 773 // completes the load and other requestors wait for completion. 774 // case 3. Bootstrap classloader - don't own objectLocker 775 // This classloader supports parallelism at the classloader level, 776 // but only allows a single load of a class/classloader pair. 777 // No performance benefit and no deadlock issues. 778 // case 4. parallelCapable user level classloaders - without objectLocker 779 // Allow parallel classloading of a class/classloader pair 780 781 { 782 MutexLocker mu(SystemDictionary_lock, THREAD); 783 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 784 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 785 if (oldprobe) { 786 // only need check_seen_thread once, not on each loop 787 // 6341374 java/lang/Instrument with -Xcomp 788 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 789 throw_circularity_error = true; 790 } else { 791 // case 1: traditional: should never see load_in_progress. 792 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 793 794 // case 3: bootstrap classloader: prevent futile classloading, 795 // wait on first requestor 796 if (class_loader.is_null()) { 797 SystemDictionary_lock->wait(); 798 } else { 799 // case 2: traditional with broken classloader lock. wait on first 800 // requestor. 801 double_lock_wait(lockObject, THREAD); 802 } 803 // Check if classloading completed while we were waiting 804 InstanceKlass* check = find_class(d_hash, name, dictionary); 805 if (check != NULL) { 806 // Klass is already loaded, so just return it 807 k = check; 808 class_has_been_loaded = true; 809 } 810 // check if other thread failed to load and cleaned up 811 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 812 } 813 } 814 } 815 } 816 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 817 // case 4: parallelCapable: allow competing threads to try 818 // LOAD_INSTANCE in parallel 819 820 if (!throw_circularity_error && !class_has_been_loaded) { 821 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 822 load_instance_added = true; 823 // For class loaders that do not acquire the classloader object lock, 824 // if they did not catch another thread holding LOAD_INSTANCE, 825 // need a check analogous to the acquire ObjectLocker/find_class 826 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 827 // one final check if the load has already completed 828 // class loaders holding the ObjectLock shouldn't find the class here 829 InstanceKlass* check = find_class(d_hash, name, dictionary); 830 if (check != NULL) { 831 // Klass is already loaded, so return it after checking/adding protection domain 832 k = check; 833 class_has_been_loaded = true; 834 } 835 } 836 } 837 838 // must throw error outside of owning lock 839 if (throw_circularity_error) { 840 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 841 ResourceMark rm(THREAD); 842 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 843 } 844 845 if (!class_has_been_loaded) { 846 847 // Do actual loading 848 k = load_instance_class(name, class_loader, THREAD); 849 850 // If everything was OK (no exceptions, no null return value), and 851 // class_loader is NOT the defining loader, do a little more bookkeeping. 852 if (!HAS_PENDING_EXCEPTION && k != NULL && 853 k->class_loader() != class_loader()) { 854 855 check_constraints(d_hash, k, class_loader, false, THREAD); 856 857 // Need to check for a PENDING_EXCEPTION again; check_constraints 858 // can throw but we may have to remove entry from the placeholder table below. 859 if (!HAS_PENDING_EXCEPTION) { 860 // Record dependency for non-parent delegation. 861 // This recording keeps the defining class loader of the klass (k) found 862 // from being unloaded while the initiating class loader is loaded 863 // even if the reference to the defining class loader is dropped 864 // before references to the initiating class loader. 865 loader_data->record_dependency(k); 866 867 { // 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(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 // But, do not add to dictionary. 1040 } 1041 1042 // Rewrite and patch constant pool here. 1043 k->link_class(CHECK_NULL); 1044 if (cp_patches != NULL) { 1045 k->constants()->patch_resolved_references(cp_patches); 1046 } 1047 1048 // If it's anonymous, initialize it now, since nobody else will. 1049 k->eager_initialize(CHECK_NULL); 1050 1051 // notify jvmti 1052 if (JvmtiExport::should_post_class_load()) { 1053 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1054 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1055 } 1056 if (class_load_start_event.should_commit()) { 1057 post_class_load_event(&class_load_start_event, k, loader_data); 1058 } 1059 } 1060 assert(unsafe_anonymous_host != NULL || NULL == cp_patches, 1061 "cp_patches only found with unsafe_anonymous_host"); 1062 1063 return k; 1064 } 1065 1066 // Add a klass to the system from a stream (called by jni_DefineClass and 1067 // JVM_DefineClass). 1068 // Note: class_name can be NULL. In that case we do not know the name of 1069 // the class until we have parsed the stream. 1070 1071 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1072 Handle class_loader, 1073 Handle protection_domain, 1074 ClassFileStream* st, 1075 TRAPS) { 1076 1077 HandleMark hm(THREAD); 1078 1079 // Classloaders that support parallelism, e.g. bootstrap classloader, 1080 // do not acquire lock here 1081 bool DoObjectLock = true; 1082 if (is_parallelCapable(class_loader)) { 1083 DoObjectLock = false; 1084 } 1085 1086 ClassLoaderData* loader_data = register_loader(class_loader); 1087 1088 // Make sure we are synchronized on the class loader before we proceed 1089 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1090 check_loader_lock_contention(lockObject, THREAD); 1091 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1092 1093 assert(st != NULL, "invariant"); 1094 1095 // Parse the stream and create a klass. 1096 // Note that we do this even though this klass might 1097 // already be present in the SystemDictionary, otherwise we would not 1098 // throw potential ClassFormatErrors. 1099 InstanceKlass* k = NULL; 1100 1101 #if INCLUDE_CDS 1102 if (!DumpSharedSpaces) { 1103 k = SystemDictionaryShared::lookup_from_stream(class_name, 1104 class_loader, 1105 protection_domain, 1106 st, 1107 CHECK_NULL); 1108 } 1109 #endif 1110 1111 if (k == NULL) { 1112 if (st->buffer() == NULL) { 1113 return NULL; 1114 } 1115 k = KlassFactory::create_from_stream(st, 1116 class_name, 1117 loader_data, 1118 protection_domain, 1119 NULL, // unsafe_anonymous_host 1120 NULL, // cp_patches 1121 CHECK_NULL); 1122 } 1123 1124 assert(k != NULL, "no klass created"); 1125 Symbol* h_name = k->name(); 1126 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1127 1128 // Add class just loaded 1129 // If a class loader supports parallel classloading handle parallel define requests 1130 // find_or_define_instance_class may return a different InstanceKlass 1131 if (is_parallelCapable(class_loader)) { 1132 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1133 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1134 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1135 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1136 loader_data->add_to_deallocate_list(k); 1137 k = defined_k; 1138 } 1139 } else { 1140 define_instance_class(k, THREAD); 1141 } 1142 1143 // If defining the class throws an exception register 'k' for cleanup. 1144 if (HAS_PENDING_EXCEPTION) { 1145 assert(k != NULL, "Must have an instance klass here!"); 1146 loader_data->add_to_deallocate_list(k); 1147 return NULL; 1148 } 1149 1150 // Make sure we have an entry in the SystemDictionary on success 1151 debug_only( { 1152 MutexLocker mu(SystemDictionary_lock, THREAD); 1153 1154 Klass* check = find_class(h_name, k->class_loader_data()); 1155 assert(check == k, "should be present in the dictionary"); 1156 } ); 1157 1158 return k; 1159 } 1160 1161 #if INCLUDE_CDS 1162 // Load a class for boot loader from the shared spaces. This also 1163 // forces the super class and all interfaces to be loaded. 1164 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name, 1165 TRAPS) { 1166 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name); 1167 if (ik != NULL && ik->is_shared_boot_class()) { 1168 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD); 1169 } 1170 return NULL; 1171 } 1172 1173 // Check if a shared class can be loaded by the specific classloader: 1174 // 1175 // NULL classloader: 1176 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1177 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1178 // be defined in an unnamed module. 1179 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1180 InstanceKlass* ik, 1181 Handle class_loader, TRAPS) { 1182 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1183 "Cannot use sharing if java.base is patched"); 1184 ResourceMark rm; 1185 int path_index = ik->shared_classpath_index(); 1186 ClassLoaderData* loader_data = class_loader_data(class_loader); 1187 if (path_index < 0) { 1188 // path_index < 0 indicates that the class is intended for a custom loader 1189 // and should not be loaded by boot/platform/app loaders 1190 if (loader_data->is_builtin_class_loader_data()) { 1191 return false; 1192 } else { 1193 return true; 1194 } 1195 } 1196 SharedClassPathEntry* ent = 1197 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); 1198 if (!Universe::is_module_initialized()) { 1199 assert(ent != NULL && ent->is_modules_image(), 1200 "Loading non-bootstrap classes before the module system is initialized"); 1201 assert(class_loader.is_null(), "sanity"); 1202 return true; 1203 } 1204 // Get the pkg_entry from the classloader 1205 TempNewSymbol pkg_name = NULL; 1206 PackageEntry* pkg_entry = NULL; 1207 ModuleEntry* mod_entry = NULL; 1208 const char* pkg_string = NULL; 1209 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1210 if (pkg_name != NULL) { 1211 pkg_string = pkg_name->as_C_string(); 1212 if (loader_data != NULL) { 1213 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1214 } 1215 if (pkg_entry != NULL) { 1216 mod_entry = pkg_entry->module(); 1217 } 1218 } 1219 1220 // If the archived class is from a module that has been patched at runtime, 1221 // the class cannot be loaded from the archive. 1222 if (mod_entry != NULL && mod_entry->is_patched()) { 1223 return false; 1224 } 1225 1226 if (class_loader.is_null()) { 1227 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1228 // The NULL classloader can load archived class originated from the 1229 // "modules" jimage and the -Xbootclasspath/a. For class from the 1230 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1231 // by the NULL classloader. 1232 if (mod_entry != NULL) { 1233 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1234 // ModuleEntry's location agrees with the archived class' origination. 1235 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1236 return true; // Module class from the "module" jimage 1237 } 1238 } 1239 1240 // If the archived class is not from the "module" jimage, the class can be 1241 // loaded by the NULL classloader if 1242 // 1243 // 1. the class is from the unamed package 1244 // 2. or, the class is not from a module defined in the NULL classloader 1245 // 3. or, the class is from an unamed module 1246 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1247 // the class is from the -Xbootclasspath/a 1248 if (pkg_string == NULL || 1249 pkg_entry == NULL || 1250 pkg_entry->in_unnamed_module()) { 1251 assert(mod_entry == NULL || 1252 mod_entry == loader_data->unnamed_module(), 1253 "the unnamed module is not defined in the classloader"); 1254 return true; 1255 } 1256 } 1257 return false; 1258 } else { 1259 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1260 ik, class_loader, pkg_string, pkg_name, 1261 pkg_entry, mod_entry, CHECK_(false)); 1262 return res; 1263 } 1264 } 1265 1266 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1267 Handle class_loader, 1268 Handle protection_domain, 1269 const ClassFileStream *cfs, 1270 TRAPS) { 1271 assert(ik != NULL, "sanity"); 1272 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once"); 1273 Symbol* class_name = ik->name(); 1274 1275 bool visible = is_shared_class_visible( 1276 class_name, ik, class_loader, CHECK_NULL); 1277 if (!visible) { 1278 return NULL; 1279 } 1280 1281 // Resolve the superclass and interfaces. They must be the same 1282 // as in dump time, because the layout of <ik> depends on 1283 // the specific layout of ik->super() and ik->local_interfaces(). 1284 // 1285 // If unexpected superclass or interfaces are found, we cannot 1286 // load <ik> from the shared archive. 1287 1288 if (ik->super() != NULL) { 1289 Symbol* cn = ik->super()->name(); 1290 Klass *s = resolve_super_or_fail(class_name, cn, 1291 class_loader, protection_domain, true, CHECK_NULL); 1292 if (s != ik->super()) { 1293 // The dynamically resolved super class is not the same as the one we used during dump time, 1294 // so we cannot use ik. 1295 return NULL; 1296 } else { 1297 assert(s->is_shared(), "must be"); 1298 } 1299 } 1300 1301 Array<InstanceKlass*>* interfaces = ik->local_interfaces(); 1302 int num_interfaces = interfaces->length(); 1303 for (int index = 0; index < num_interfaces; index++) { 1304 InstanceKlass* k = interfaces->at(index); 1305 Symbol* name = k->name(); 1306 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1307 if (k != i) { 1308 // The dynamically resolved interface class is not the same as the one we used during dump time, 1309 // so we cannot use ik. 1310 return NULL; 1311 } else { 1312 assert(i->is_shared(), "must be"); 1313 } 1314 } 1315 1316 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1317 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL); 1318 if (new_ik != NULL) { 1319 // The class is changed by CFLH. Return the new class. The shared class is 1320 // not used. 1321 return new_ik; 1322 } 1323 1324 // Adjust methods to recover missing data. They need addresses for 1325 // interpreter entry points and their default native method address 1326 // must be reset. 1327 1328 // Updating methods must be done under a lock so multiple 1329 // threads don't update these in parallel 1330 // 1331 // Shared classes are all currently loaded by either the bootstrap or 1332 // internal parallel class loaders, so this will never cause a deadlock 1333 // on a custom class loader lock. 1334 1335 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1336 { 1337 HandleMark hm(THREAD); 1338 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1339 check_loader_lock_contention(lockObject, THREAD); 1340 ObjectLocker ol(lockObject, THREAD, true); 1341 // prohibited package check assumes all classes loaded from archive call 1342 // restore_unshareable_info which calls ik->set_package() 1343 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1344 } 1345 1346 ik->print_class_load_logging(loader_data, NULL, NULL); 1347 1348 // For boot loader, ensure that GetSystemPackage knows that a class in this 1349 // package was loaded. 1350 if (class_loader.is_null()) { 1351 int path_index = ik->shared_classpath_index(); 1352 ResourceMark rm; 1353 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1354 } 1355 1356 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1357 // Only dump the classes that can be stored into CDS archive 1358 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1359 ResourceMark rm(THREAD); 1360 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1361 classlist_file->flush(); 1362 } 1363 } 1364 1365 // notify a class loaded from shared object 1366 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1367 1368 ik->set_has_passed_fingerprint_check(false); 1369 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1370 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1371 uint64_t cds_fp = ik->get_stored_fingerprint(); 1372 if (aot_fp != 0 && aot_fp == cds_fp) { 1373 // This class matches with a class saved in an AOT library 1374 ik->set_has_passed_fingerprint_check(true); 1375 } else { 1376 ResourceMark rm; 1377 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1378 } 1379 } 1380 1381 return ik; 1382 } 1383 #endif // INCLUDE_CDS 1384 1385 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1386 1387 if (class_loader.is_null()) { 1388 ResourceMark rm; 1389 PackageEntry* pkg_entry = NULL; 1390 bool search_only_bootloader_append = false; 1391 ClassLoaderData *loader_data = class_loader_data(class_loader); 1392 1393 // Find the package in the boot loader's package entry table. 1394 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1395 if (pkg_name != NULL) { 1396 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1397 } 1398 1399 // Prior to attempting to load the class, enforce the boot loader's 1400 // visibility boundaries. 1401 if (!Universe::is_module_initialized()) { 1402 // During bootstrapping, prior to module initialization, any 1403 // class attempting to be loaded must be checked against the 1404 // java.base packages in the boot loader's PackageEntryTable. 1405 // No class outside of java.base is allowed to be loaded during 1406 // this bootstrapping window. 1407 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1408 // Class is either in the unnamed package or in 1409 // a named package within the unnamed module. Either 1410 // case is outside of java.base, do not attempt to 1411 // load the class post java.base definition. If 1412 // java.base has not been defined, let the class load 1413 // and its package will be checked later by 1414 // ModuleEntryTable::verify_javabase_packages. 1415 if (ModuleEntryTable::javabase_defined()) { 1416 return NULL; 1417 } 1418 } else { 1419 // Check that the class' package is defined within java.base. 1420 ModuleEntry* mod_entry = pkg_entry->module(); 1421 Symbol* mod_entry_name = mod_entry->name(); 1422 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1423 return NULL; 1424 } 1425 } 1426 } else { 1427 // After the module system has been initialized, check if the class' 1428 // package is in a module defined to the boot loader. 1429 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1430 // Class is either in the unnamed package, in a named package 1431 // within a module not defined to the boot loader or in a 1432 // a named package within the unnamed module. In all cases, 1433 // limit visibility to search for the class only in the boot 1434 // loader's append path. 1435 if (!ClassLoader::has_bootclasspath_append()) { 1436 // If there is no bootclasspath append entry, no need to continue 1437 // searching. 1438 return NULL; 1439 } 1440 search_only_bootloader_append = true; 1441 } 1442 } 1443 1444 // Prior to bootstrapping's module initialization, never load a class outside 1445 // of the boot loader's module path 1446 assert(Universe::is_module_initialized() || 1447 !search_only_bootloader_append, 1448 "Attempt to load a class outside of boot loader's module path"); 1449 1450 // Search for classes in the CDS archive. 1451 InstanceKlass* k = NULL; 1452 { 1453 #if INCLUDE_CDS 1454 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1455 k = load_shared_boot_class(class_name, THREAD); 1456 #endif 1457 } 1458 1459 if (k == NULL) { 1460 // Use VM class loader 1461 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1462 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1463 } 1464 1465 // find_or_define_instance_class may return a different InstanceKlass 1466 if (k != NULL) { 1467 InstanceKlass* defined_k = 1468 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1469 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1470 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1471 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1472 loader_data->add_to_deallocate_list(k); 1473 k = defined_k; 1474 } else if (HAS_PENDING_EXCEPTION) { 1475 loader_data->add_to_deallocate_list(k); 1476 return NULL; 1477 } 1478 } 1479 return k; 1480 } else { 1481 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1482 ResourceMark rm(THREAD); 1483 1484 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1485 JavaThread* jt = (JavaThread*) THREAD; 1486 1487 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1488 ClassLoader::perf_app_classload_selftime(), 1489 ClassLoader::perf_app_classload_count(), 1490 jt->get_thread_stat()->perf_recursion_counts_addr(), 1491 jt->get_thread_stat()->perf_timers_addr(), 1492 PerfClassTraceTime::CLASS_LOAD); 1493 1494 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1495 // Translate to external class name format, i.e., convert '/' chars to '.' 1496 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1497 1498 JavaValue result(T_OBJECT); 1499 1500 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1501 1502 // Call public unsynchronized loadClass(String) directly for all class loaders. 1503 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1504 // acquire a class-name based lock rather than the class loader object lock. 1505 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1506 JavaCalls::call_virtual(&result, 1507 class_loader, 1508 spec_klass, 1509 vmSymbols::loadClass_name(), 1510 vmSymbols::string_class_signature(), 1511 string, 1512 CHECK_NULL); 1513 1514 assert(result.get_type() == T_OBJECT, "just checking"); 1515 oop obj = (oop) result.get_jobject(); 1516 1517 // Primitive classes return null since forName() can not be 1518 // used to obtain any of the Class objects representing primitives or void 1519 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1520 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1521 // For user defined Java class loaders, check that the name returned is 1522 // the same as that requested. This check is done for the bootstrap 1523 // loader when parsing the class file. 1524 if (class_name == k->name()) { 1525 return k; 1526 } 1527 } 1528 // Class is not found or has the wrong name, return NULL 1529 return NULL; 1530 } 1531 } 1532 1533 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) { 1534 EventClassDefine event; 1535 if (event.should_commit()) { 1536 event.set_definedClass(k); 1537 event.set_definingClassLoader(def_cld); 1538 event.commit(); 1539 } 1540 } 1541 1542 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1543 1544 HandleMark hm(THREAD); 1545 ClassLoaderData* loader_data = k->class_loader_data(); 1546 Handle class_loader_h(THREAD, loader_data->class_loader()); 1547 1548 // for bootstrap and other parallel classloaders don't acquire lock, 1549 // use placeholder token 1550 // If a parallelCapable class loader calls define_instance_class instead of 1551 // find_or_define_instance_class to get here, we have a timing 1552 // hole with systemDictionary updates and check_constraints 1553 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1554 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1555 compute_loader_lock_object(class_loader_h, THREAD)), 1556 "define called without lock"); 1557 } 1558 1559 // Check class-loading constraints. Throw exception if violation is detected. 1560 // Grabs and releases SystemDictionary_lock 1561 // The check_constraints/find_class call and update_dictionary sequence 1562 // must be "atomic" for a specific class/classloader pair so we never 1563 // define two different instanceKlasses for that class/classloader pair. 1564 // Existing classloaders will call define_instance_class with the 1565 // classloader lock held 1566 // Parallel classloaders will call find_or_define_instance_class 1567 // which will require a token to perform the define class 1568 Symbol* name_h = k->name(); 1569 Dictionary* dictionary = loader_data->dictionary(); 1570 unsigned int d_hash = dictionary->compute_hash(name_h); 1571 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1572 1573 // Register class just loaded with class loader (placed in Vector) 1574 // Note we do this before updating the dictionary, as this can 1575 // fail with an OutOfMemoryError (if it does, we will *not* put this 1576 // class in the dictionary and will not update the class hierarchy). 1577 // JVMTI FollowReferences needs to find the classes this way. 1578 if (k->class_loader() != NULL) { 1579 methodHandle m(THREAD, Universe::loader_addClass_method()); 1580 JavaValue result(T_VOID); 1581 JavaCallArguments args(class_loader_h); 1582 args.push_oop(Handle(THREAD, k->java_mirror())); 1583 JavaCalls::call(&result, m, &args, CHECK); 1584 } 1585 1586 // Add the new class. We need recompile lock during update of CHA. 1587 { 1588 unsigned int p_hash = placeholders()->compute_hash(name_h); 1589 int p_index = placeholders()->hash_to_index(p_hash); 1590 1591 MutexLocker mu_r(Compile_lock, THREAD); 1592 1593 // Add to class hierarchy, initialize vtables, and do possible 1594 // deoptimizations. 1595 add_to_hierarchy(k, CHECK); // No exception, but can block 1596 1597 // Add to systemDictionary - so other classes can see it. 1598 // Grabs and releases SystemDictionary_lock 1599 update_dictionary(d_hash, p_index, p_hash, 1600 k, class_loader_h, THREAD); 1601 } 1602 k->eager_initialize(THREAD); 1603 1604 // notify jvmti 1605 if (JvmtiExport::should_post_class_load()) { 1606 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1607 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1608 1609 } 1610 post_class_define_event(k, loader_data); 1611 } 1612 1613 // Support parallel classloading 1614 // All parallel class loaders, including bootstrap classloader 1615 // lock a placeholder entry for this class/class_loader pair 1616 // to allow parallel defines of different classes for this class loader 1617 // With AllowParallelDefine flag==true, in case they do not synchronize around 1618 // FindLoadedClass/DefineClass, calls, we check for parallel 1619 // loading for them, wait if a defineClass is in progress 1620 // and return the initial requestor's results 1621 // This flag does not apply to the bootstrap classloader. 1622 // With AllowParallelDefine flag==false, call through to define_instance_class 1623 // which will throw LinkageError: duplicate class definition. 1624 // False is the requested default. 1625 // For better performance, the class loaders should synchronize 1626 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1627 // potentially waste time reading and parsing the bytestream. 1628 // Note: VM callers should ensure consistency of k/class_name,class_loader 1629 // Be careful when modifying this code: once you have run 1630 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1631 // you need to find_and_remove it before returning. 1632 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1633 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1634 InstanceKlass* k, TRAPS) { 1635 1636 Symbol* name_h = k->name(); // passed in class_name may be null 1637 ClassLoaderData* loader_data = class_loader_data(class_loader); 1638 Dictionary* dictionary = loader_data->dictionary(); 1639 1640 unsigned int d_hash = dictionary->compute_hash(name_h); 1641 1642 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1643 unsigned int p_hash = placeholders()->compute_hash(name_h); 1644 int p_index = placeholders()->hash_to_index(p_hash); 1645 PlaceholderEntry* probe; 1646 1647 { 1648 MutexLocker mu(SystemDictionary_lock, THREAD); 1649 // First check if class already defined 1650 if (is_parallelDefine(class_loader)) { 1651 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1652 if (check != NULL) { 1653 return check; 1654 } 1655 } 1656 1657 // Acquire define token for this class/classloader 1658 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1659 // Wait if another thread defining in parallel 1660 // All threads wait - even those that will throw duplicate class: otherwise 1661 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1662 // if other thread has not finished updating dictionary 1663 while (probe->definer() != NULL) { 1664 SystemDictionary_lock->wait(); 1665 } 1666 // Only special cases allow parallel defines and can use other thread's results 1667 // Other cases fall through, and may run into duplicate defines 1668 // caught by finding an entry in the SystemDictionary 1669 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1670 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1671 SystemDictionary_lock->notify_all(); 1672 #ifdef ASSERT 1673 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1674 assert(check != NULL, "definer missed recording success"); 1675 #endif 1676 return probe->instance_klass(); 1677 } else { 1678 // This thread will define the class (even if earlier thread tried and had an error) 1679 probe->set_definer(THREAD); 1680 } 1681 } 1682 1683 define_instance_class(k, THREAD); 1684 1685 Handle linkage_exception = Handle(); // null handle 1686 1687 // definer must notify any waiting threads 1688 { 1689 MutexLocker mu(SystemDictionary_lock, THREAD); 1690 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1691 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1692 if (probe != NULL) { 1693 if (HAS_PENDING_EXCEPTION) { 1694 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1695 CLEAR_PENDING_EXCEPTION; 1696 } else { 1697 probe->set_instance_klass(k); 1698 } 1699 probe->set_definer(NULL); 1700 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1701 SystemDictionary_lock->notify_all(); 1702 } 1703 } 1704 1705 // Can't throw exception while holding lock due to rank ordering 1706 if (linkage_exception() != NULL) { 1707 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1708 } 1709 1710 return k; 1711 } 1712 1713 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1714 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1715 if (class_loader.is_null()) { 1716 return Handle(THREAD, _system_loader_lock_obj); 1717 } else { 1718 return class_loader; 1719 } 1720 } 1721 1722 // This method is added to check how often we have to wait to grab loader 1723 // lock. The results are being recorded in the performance counters defined in 1724 // ClassLoader::_sync_systemLoaderLockContentionRate and 1725 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1726 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1727 if (!UsePerfData) { 1728 return; 1729 } 1730 1731 assert(!loader_lock.is_null(), "NULL lock object"); 1732 1733 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1734 == ObjectSynchronizer::owner_other) { 1735 // contention will likely happen, so increment the corresponding 1736 // contention counter. 1737 if (loader_lock() == _system_loader_lock_obj) { 1738 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1739 } else { 1740 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1741 } 1742 } 1743 } 1744 1745 // ---------------------------------------------------------------------------- 1746 // Lookup 1747 1748 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1749 Symbol* class_name, 1750 Dictionary* dictionary) { 1751 assert_locked_or_safepoint(SystemDictionary_lock); 1752 int index = dictionary->hash_to_index(hash); 1753 return dictionary->find_class(index, hash, class_name); 1754 } 1755 1756 1757 // Basic find on classes in the midst of being loaded 1758 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1759 ClassLoaderData* loader_data) { 1760 assert_locked_or_safepoint(SystemDictionary_lock); 1761 unsigned int p_hash = placeholders()->compute_hash(class_name); 1762 int p_index = placeholders()->hash_to_index(p_hash); 1763 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1764 } 1765 1766 1767 // Used for assertions and verification only 1768 // Precalculating the hash and index is an optimization because there are many lookups 1769 // before adding the class. 1770 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1771 assert_locked_or_safepoint(SystemDictionary_lock); 1772 #ifndef ASSERT 1773 guarantee(VerifyBeforeGC || 1774 VerifyDuringGC || 1775 VerifyBeforeExit || 1776 VerifyDuringStartup || 1777 VerifyAfterGC, "too expensive"); 1778 #endif 1779 1780 Dictionary* dictionary = loader_data->dictionary(); 1781 unsigned int d_hash = dictionary->compute_hash(class_name); 1782 return find_class(d_hash, class_name, dictionary); 1783 } 1784 1785 1786 // ---------------------------------------------------------------------------- 1787 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1788 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1789 // before a new class is used. 1790 1791 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1792 assert(k != NULL, "just checking"); 1793 assert_locked_or_safepoint(Compile_lock); 1794 1795 k->set_init_state(InstanceKlass::loaded); 1796 // make sure init_state store is already done. 1797 // The compiler reads the hierarchy outside of the Compile_lock. 1798 // Access ordering is used to add to hierarchy. 1799 1800 // Link into hierachy. 1801 k->append_to_sibling_list(); // add to superklass/sibling list 1802 k->process_interfaces(THREAD); // handle all "implements" declarations 1803 1804 // Now flush all code that depended on old class hierarchy. 1805 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1806 CodeCache::flush_dependents_on(k); 1807 } 1808 1809 // ---------------------------------------------------------------------------- 1810 // GC support 1811 1812 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1813 // Note: anonymous classes are not in the SD. 1814 bool SystemDictionary::do_unloading(GCTimer* gc_timer) { 1815 1816 bool unloading_occurred; 1817 bool is_concurrent = !SafepointSynchronize::is_at_safepoint(); 1818 { 1819 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1820 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks. 1821 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1822 unloading_occurred = ClassLoaderDataGraph::do_unloading(); 1823 if (unloading_occurred) { 1824 MutexLocker ml2(is_concurrent ? Module_lock : NULL); 1825 JFR_ONLY(Jfr::on_unloading_classes();) 1826 1827 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL); 1828 ClassLoaderDataGraph::clean_module_and_package_info(); 1829 constraints()->purge_loader_constraints(); 1830 resolution_errors()->purge_resolution_errors(); 1831 } 1832 } 1833 1834 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer); 1835 1836 if (unloading_occurred) { 1837 SymbolTable::trigger_cleanup(); 1838 1839 // Oops referenced by the protection domain cache table may get unreachable independently 1840 // of the class loader (eg. cached protection domain oops). So we need to 1841 // explicitly unlink them here. 1842 // All protection domain oops are linked to the caller class, so if nothing 1843 // unloads, this is not needed. 1844 _pd_cache_table->trigger_cleanup(); 1845 } 1846 1847 return unloading_occurred; 1848 } 1849 1850 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) { 1851 f->do_oop(&_java_system_loader); 1852 f->do_oop(&_java_platform_loader); 1853 f->do_oop(&_system_loader_lock_obj); 1854 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1855 1856 // Visit extra methods 1857 invoke_method_table()->oops_do(f); 1858 1859 if (include_handles) { 1860 OopStorageSet::vm_global()->oops_do(f); 1861 } 1862 } 1863 1864 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1865 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1866 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1867 it->push(well_known_klass_addr((WKID)id)); 1868 } 1869 } 1870 1871 void SystemDictionary::methods_do(void f(Method*)) { 1872 // Walk methods in loaded classes 1873 MutexLocker ml(ClassLoaderDataGraph_lock); 1874 ClassLoaderDataGraph::methods_do(f); 1875 // Walk method handle intrinsics 1876 invoke_method_table()->methods_do(f); 1877 } 1878 1879 // ---------------------------------------------------------------------------- 1880 // Initialization 1881 1882 void SystemDictionary::initialize(TRAPS) { 1883 // Allocate arrays 1884 _placeholders = new PlaceholderTable(_placeholder_table_size); 1885 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1886 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1887 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1888 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 1889 1890 // Allocate private object used as system class loader lock 1891 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1892 // Initialize basic classes 1893 resolve_well_known_classes(CHECK); 1894 } 1895 1896 // Compact table of directions on the initialization of klasses: 1897 static const short wk_init_info[] = { 1898 #define WK_KLASS_INIT_INFO(name, symbol) \ 1899 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)), 1900 1901 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1902 #undef WK_KLASS_INIT_INFO 1903 0 1904 }; 1905 1906 #ifdef ASSERT 1907 bool SystemDictionary::is_well_known_klass(Symbol* class_name) { 1908 int sid; 1909 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) { 1910 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1911 if (class_name == symbol) { 1912 return true; 1913 } 1914 } 1915 return false; 1916 } 1917 #endif 1918 1919 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) { 1920 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1921 int sid = wk_init_info[id - FIRST_WKID]; 1922 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1923 InstanceKlass** klassp = &_well_known_klasses[id]; 1924 1925 if ((*klassp) == NULL) { 1926 Klass* k = resolve_or_fail(symbol, true, CHECK_0); 1927 (*klassp) = InstanceKlass::cast(k); 1928 } 1929 return ((*klassp) != NULL); 1930 } 1931 1932 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1933 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1934 for (int id = (int)start_id; id < (int)limit_id; id++) { 1935 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1936 resolve_wk_klass((WKID)id, CHECK); 1937 } 1938 1939 // move the starting value forward to the limit: 1940 start_id = limit_id; 1941 } 1942 1943 void SystemDictionary::resolve_well_known_classes(TRAPS) { 1944 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once"); 1945 1946 // Create the ModuleEntry for java.base. This call needs to be done here, 1947 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 1948 ClassLoader::classLoader_init2(CHECK); 1949 1950 // Preload commonly used klasses 1951 WKID scan = FIRST_WKID; 1952 // first do Object, then String, Class 1953 #if INCLUDE_CDS 1954 if (UseSharedSpaces) { 1955 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1956 1957 // It's unsafe to access the archived heap regions before they 1958 // are fixed up, so we must do the fixup as early as possible 1959 // before the archived java objects are accessed by functions 1960 // such as java_lang_Class::restore_archived_mirror and 1961 // ConstantPool::restore_unshareable_info (restores the archived 1962 // resolved_references array object). 1963 // 1964 // HeapShared::fixup_mapped_heap_regions() fills the empty 1965 // spaces in the archived heap regions and may use 1966 // SystemDictionary::Object_klass(), so we can do this only after 1967 // Object_klass is resolved. See the above resolve_wk_klasses_through() 1968 // call. No mirror objects are accessed/restored in the above call. 1969 // Mirrors are restored after java.lang.Class is loaded. 1970 HeapShared::fixup_mapped_heap_regions(); 1971 1972 // Initialize the constant pool for the Object_class 1973 assert(Object_klass()->is_shared(), "must be"); 1974 Object_klass()->constants()->restore_unshareable_info(CHECK); 1975 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1976 } else 1977 #endif 1978 { 1979 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1980 } 1981 1982 // Calculate offsets for String and Class classes since they are loaded and 1983 // can be used after this point. 1984 java_lang_String::compute_offsets(); 1985 java_lang_Class::compute_offsets(); 1986 1987 // Fixup mirrors for classes loaded before java.lang.Class. 1988 // These calls iterate over the objects currently in the perm gen 1989 // so calling them at this point is matters (not before when there 1990 // are fewer objects and not later after there are more objects 1991 // in the perm gen. 1992 Universe::initialize_basic_type_mirrors(CHECK); 1993 Universe::fixup_mirrors(CHECK); 1994 1995 // do a bunch more: 1996 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 1997 1998 // Preload ref klasses and set reference types 1999 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2000 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2001 2002 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2003 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2004 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2005 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2006 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2007 2008 // JSR 292 classes 2009 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2010 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2011 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK); 2012 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK); 2013 WKID last = WKID_LIMIT; 2014 resolve_wk_klasses_until(last, scan, CHECK); 2015 2016 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2017 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2018 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2019 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2020 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2021 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2022 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2023 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2024 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2025 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2026 2027 { // Compute whether we should use checkPackageAccess or NOT 2028 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2029 _has_checkPackageAccess = (method != NULL); 2030 } 2031 2032 #ifdef ASSERT 2033 if (UseSharedSpaces) { 2034 assert(JvmtiExport::is_early_phase(), 2035 "All well known classes must be resolved in JVMTI early phase"); 2036 for (int i = FIRST_WKID; i < last; i++) { 2037 InstanceKlass* k = _well_known_klasses[i]; 2038 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook"); 2039 } 2040 } 2041 #endif 2042 } 2043 2044 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2045 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2046 BasicType SystemDictionary::box_klass_type(Klass* k) { 2047 assert(k != NULL, ""); 2048 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2049 if (_box_klasses[i] == k) 2050 return (BasicType)i; 2051 } 2052 return T_OBJECT; 2053 } 2054 2055 // Constraints on class loaders. The details of the algorithm can be 2056 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2057 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2058 // that the dictionary needs to maintain a set of contraints that 2059 // must be satisfied by all classes in the dictionary. 2060 // if defining is true, then LinkageError if already in dictionary 2061 // if initiating loader, then ok if InstanceKlass matches existing entry 2062 2063 void SystemDictionary::check_constraints(unsigned int d_hash, 2064 InstanceKlass* k, 2065 Handle class_loader, 2066 bool defining, 2067 TRAPS) { 2068 ResourceMark rm(THREAD); 2069 stringStream ss; 2070 bool throwException = false; 2071 2072 { 2073 Symbol *name = k->name(); 2074 ClassLoaderData *loader_data = class_loader_data(class_loader); 2075 2076 MutexLocker mu(SystemDictionary_lock, THREAD); 2077 2078 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2079 if (check != NULL) { 2080 // If different InstanceKlass - duplicate class definition, 2081 // else - ok, class loaded by a different thread in parallel. 2082 // We should only have found it if it was done loading and ok to use. 2083 // The dictionary only holds instance classes, placeholders 2084 // also hold array classes. 2085 2086 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2087 if ((defining == true) || (k != check)) { 2088 throwException = true; 2089 ss.print("loader %s", loader_data->loader_name_and_id()); 2090 ss.print(" attempted duplicate %s definition for %s. (%s)", 2091 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true)); 2092 } else { 2093 return; 2094 } 2095 } 2096 2097 #ifdef ASSERT 2098 Symbol* ph_check = find_placeholder(name, loader_data); 2099 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2100 #endif 2101 2102 if (throwException == false) { 2103 if (constraints()->check_or_update(k, class_loader, name) == false) { 2104 throwException = true; 2105 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id()); 2106 ss.print(" wants to load %s %s.", 2107 k->external_kind(), k->external_name()); 2108 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); 2109 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) { 2110 ss.print(" A different %s with the same name was previously loaded by %s. (%s)", 2111 existing_klass->external_kind(), 2112 existing_klass->class_loader_data()->loader_name_and_id(), 2113 existing_klass->class_in_module_of_loader(false, true)); 2114 } else { 2115 ss.print(" (%s)", k->class_in_module_of_loader(false, true)); 2116 } 2117 } 2118 } 2119 } 2120 2121 // Throw error now if needed (cannot throw while holding 2122 // SystemDictionary_lock because of rank ordering) 2123 if (throwException == true) { 2124 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); 2125 } 2126 } 2127 2128 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2129 // have been called. 2130 void SystemDictionary::update_dictionary(unsigned int d_hash, 2131 int p_index, unsigned int p_hash, 2132 InstanceKlass* k, 2133 Handle class_loader, 2134 TRAPS) { 2135 // Compile_lock prevents systemDictionary updates during compilations 2136 assert_locked_or_safepoint(Compile_lock); 2137 Symbol* name = k->name(); 2138 ClassLoaderData *loader_data = class_loader_data(class_loader); 2139 2140 { 2141 MutexLocker mu1(SystemDictionary_lock, THREAD); 2142 2143 // See whether biased locking is enabled and if so set it for this 2144 // klass. 2145 // Note that this must be done past the last potential blocking 2146 // point / safepoint. We might enable biased locking lazily using a 2147 // VM_Operation to iterate the SystemDictionary and installing the 2148 // biasable mark word into each InstanceKlass's prototype header. 2149 // To avoid race conditions where we accidentally miss enabling the 2150 // optimization for one class in the process of being added to the 2151 // dictionary, we must not safepoint after the test of 2152 // BiasedLocking::enabled(). 2153 if (UseBiasedLocking && BiasedLocking::enabled()) { 2154 // Set biased locking bit for all loaded classes; it will be 2155 // cleared if revocation occurs too often for this type 2156 // NOTE that we must only do this when the class is initally 2157 // defined, not each time it is referenced from a new class loader 2158 if (k->class_loader() == class_loader()) { 2159 k->set_prototype_header(markWord::biased_locking_prototype()); 2160 } 2161 } 2162 2163 // Make a new dictionary entry. 2164 Dictionary* dictionary = loader_data->dictionary(); 2165 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2166 if (sd_check == NULL) { 2167 dictionary->add_klass(d_hash, name, k); 2168 } 2169 #ifdef ASSERT 2170 sd_check = find_class(d_hash, name, dictionary); 2171 assert (sd_check != NULL, "should have entry in dictionary"); 2172 // Note: there may be a placeholder entry: for circularity testing 2173 // or for parallel defines 2174 #endif 2175 SystemDictionary_lock->notify_all(); 2176 } 2177 } 2178 2179 2180 // Try to find a class name using the loader constraints. The 2181 // loader constraints might know about a class that isn't fully loaded 2182 // yet and these will be ignored. 2183 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2184 Symbol* class_name, Handle class_loader, TRAPS) { 2185 2186 // First see if it has been loaded directly. 2187 // Force the protection domain to be null. (This removes protection checks.) 2188 Handle no_protection_domain; 2189 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2190 no_protection_domain, CHECK_NULL); 2191 if (klass != NULL) 2192 return klass; 2193 2194 // Now look to see if it has been loaded elsewhere, and is subject to 2195 // a loader constraint that would require this loader to return the 2196 // klass that is already loaded. 2197 if (FieldType::is_array(class_name)) { 2198 // For array classes, their Klass*s are not kept in the 2199 // constraint table. The element Klass*s are. 2200 FieldArrayInfo fd; 2201 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2202 if (t != T_OBJECT) { 2203 klass = Universe::typeArrayKlassObj(t); 2204 } else { 2205 MutexLocker mu(SystemDictionary_lock, THREAD); 2206 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2207 } 2208 // If element class already loaded, allocate array klass 2209 if (klass != NULL) { 2210 klass = klass->array_klass_or_null(fd.dimension()); 2211 } 2212 } else { 2213 MutexLocker mu(SystemDictionary_lock, THREAD); 2214 // Non-array classes are easy: simply check the constraint table. 2215 klass = constraints()->find_constrained_klass(class_name, class_loader); 2216 } 2217 2218 return klass; 2219 } 2220 2221 2222 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2223 Handle class_loader1, 2224 Handle class_loader2, 2225 Thread* THREAD) { 2226 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2227 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2228 2229 Symbol* constraint_name = NULL; 2230 // Needs to be in same scope as constraint_name in case a Symbol is created and 2231 // assigned to constraint_name. 2232 FieldArrayInfo fd; 2233 if (!FieldType::is_array(class_name)) { 2234 constraint_name = class_name; 2235 } else { 2236 // For array classes, their Klass*s are not kept in the 2237 // constraint table. The element classes are. 2238 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2239 // primitive types always pass 2240 if (t != T_OBJECT) { 2241 return true; 2242 } else { 2243 constraint_name = fd.object_key(); 2244 } 2245 } 2246 2247 Dictionary* dictionary1 = loader_data1->dictionary(); 2248 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2249 2250 Dictionary* dictionary2 = loader_data2->dictionary(); 2251 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2252 2253 { 2254 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2255 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2256 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2257 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2258 klass2, class_loader2); 2259 } 2260 } 2261 2262 // Add entry to resolution error table to record the error when the first 2263 // attempt to resolve a reference to a class has failed. 2264 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2265 Symbol* error, Symbol* message) { 2266 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2267 int index = resolution_errors()->hash_to_index(hash); 2268 { 2269 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2270 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2271 } 2272 } 2273 2274 // Delete a resolution error for RedefineClasses for a constant pool is going away 2275 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2276 resolution_errors()->delete_entry(pool); 2277 } 2278 2279 // Lookup resolution error table. Returns error if found, otherwise NULL. 2280 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2281 Symbol** message) { 2282 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2283 int index = resolution_errors()->hash_to_index(hash); 2284 { 2285 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2286 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2287 if (entry != NULL) { 2288 *message = entry->message(); 2289 return entry->error(); 2290 } else { 2291 return NULL; 2292 } 2293 } 2294 } 2295 2296 2297 // Signature constraints ensure that callers and callees agree about 2298 // the meaning of type names in their signatures. This routine is the 2299 // intake for constraints. It collects them from several places: 2300 // 2301 // * LinkResolver::resolve_method (if check_access is true) requires 2302 // that the resolving class (the caller) and the defining class of 2303 // the resolved method (the callee) agree on each type in the 2304 // method's signature. 2305 // 2306 // * LinkResolver::resolve_interface_method performs exactly the same 2307 // checks. 2308 // 2309 // * LinkResolver::resolve_field requires that the constant pool 2310 // attempting to link to a field agree with the field's defining 2311 // class about the type of the field signature. 2312 // 2313 // * klassVtable::initialize_vtable requires that, when a class 2314 // overrides a vtable entry allocated by a superclass, that the 2315 // overriding method (i.e., the callee) agree with the superclass 2316 // on each type in the method's signature. 2317 // 2318 // * klassItable::initialize_itable requires that, when a class fills 2319 // in its itables, for each non-abstract method installed in an 2320 // itable, the method (i.e., the callee) agree with the interface 2321 // on each type in the method's signature. 2322 // 2323 // All those methods have a boolean (check_access, checkconstraints) 2324 // which turns off the checks. This is used from specialized contexts 2325 // such as bootstrapping, dumping, and debugging. 2326 // 2327 // No direct constraint is placed between the class and its 2328 // supertypes. Constraints are only placed along linked relations 2329 // between callers and callees. When a method overrides or implements 2330 // an abstract method in a supertype (superclass or interface), the 2331 // constraints are placed as if the supertype were the caller to the 2332 // overriding method. (This works well, since callers to the 2333 // supertype have already established agreement between themselves and 2334 // the supertype.) As a result of all this, a class can disagree with 2335 // its supertype about the meaning of a type name, as long as that 2336 // class neither calls a relevant method of the supertype, nor is 2337 // called (perhaps via an override) from the supertype. 2338 // 2339 // 2340 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2341 // 2342 // Make sure all class components (including arrays) in the given 2343 // signature will be resolved to the same class in both loaders. 2344 // Returns the name of the type that failed a loader constraint check, or 2345 // NULL if no constraint failed. No exception except OOME is thrown. 2346 // Arrays are not added to the loader constraint table, their elements are. 2347 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2348 Handle loader1, Handle loader2, 2349 bool is_method, TRAPS) { 2350 // Nothing to do if loaders are the same. 2351 if (loader1() == loader2()) { 2352 return NULL; 2353 } 2354 2355 SignatureStream sig_strm(signature, is_method); 2356 while (!sig_strm.is_done()) { 2357 if (sig_strm.is_object()) { 2358 Symbol* sig = sig_strm.as_symbol(); 2359 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2360 return sig; 2361 } 2362 } 2363 sig_strm.next(); 2364 } 2365 return NULL; 2366 } 2367 2368 2369 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2370 Symbol* signature, 2371 TRAPS) { 2372 methodHandle empty; 2373 assert(MethodHandles::is_signature_polymorphic(iid) && 2374 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2375 iid != vmIntrinsics::_invokeGeneric, 2376 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2377 2378 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2379 int index = invoke_method_table()->hash_to_index(hash); 2380 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2381 methodHandle m; 2382 if (spe == NULL || spe->method() == NULL) { 2383 spe = NULL; 2384 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2385 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2386 if (!Arguments::is_interpreter_only()) { 2387 // Generate a compiled form of the MH intrinsic. 2388 AdapterHandlerLibrary::create_native_wrapper(m); 2389 // Check if have the compiled code. 2390 if (!m->has_compiled_code()) { 2391 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2392 "Out of space in CodeCache for method handle intrinsic", empty); 2393 } 2394 } 2395 // Now grab the lock. We might have to throw away the new method, 2396 // if a racing thread has managed to install one at the same time. 2397 { 2398 MutexLocker ml(SystemDictionary_lock, THREAD); 2399 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2400 if (spe == NULL) 2401 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2402 if (spe->method() == NULL) 2403 spe->set_method(m()); 2404 } 2405 } 2406 2407 assert(spe != NULL && spe->method() != NULL, ""); 2408 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2409 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2410 "MH intrinsic invariant"); 2411 return spe->method(); 2412 } 2413 2414 // Helper for unpacking the return value from linkMethod and linkCallSite. 2415 static methodHandle unpack_method_and_appendix(Handle mname, 2416 Klass* accessing_klass, 2417 objArrayHandle appendix_box, 2418 Handle* appendix_result, 2419 TRAPS) { 2420 methodHandle empty; 2421 if (mname.not_null()) { 2422 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2423 if (m != NULL) { 2424 oop appendix = appendix_box->obj_at(0); 2425 if (TraceMethodHandles) { 2426 #ifndef PRODUCT 2427 ttyLocker ttyl; 2428 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2429 m->print(); 2430 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2431 tty->cr(); 2432 #endif //PRODUCT 2433 } 2434 (*appendix_result) = Handle(THREAD, appendix); 2435 // the target is stored in the cpCache and if a reference to this 2436 // MemberName is dropped we need a way to make sure the 2437 // class_loader containing this method is kept alive. 2438 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2439 this_key->record_dependency(m->method_holder()); 2440 return methodHandle(THREAD, m); 2441 } 2442 } 2443 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2444 return empty; 2445 } 2446 2447 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2448 Symbol* name, 2449 Symbol* signature, 2450 Klass* accessing_klass, 2451 Handle *appendix_result, 2452 TRAPS) { 2453 methodHandle empty; 2454 assert(THREAD->can_call_java() ,""); 2455 Handle method_type = 2456 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2457 2458 int ref_kind = JVM_REF_invokeVirtual; 2459 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2460 Handle name_str (THREAD, name_oop); 2461 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2462 assert(appendix_box->obj_at(0) == NULL, ""); 2463 2464 // This should not happen. JDK code should take care of that. 2465 if (accessing_klass == NULL || method_type.is_null()) { 2466 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2467 } 2468 2469 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2470 JavaCallArguments args; 2471 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2472 args.push_int(ref_kind); 2473 args.push_oop(Handle(THREAD, klass->java_mirror())); 2474 args.push_oop(name_str); 2475 args.push_oop(method_type); 2476 args.push_oop(appendix_box); 2477 JavaValue result(T_OBJECT); 2478 JavaCalls::call_static(&result, 2479 SystemDictionary::MethodHandleNatives_klass(), 2480 vmSymbols::linkMethod_name(), 2481 vmSymbols::linkMethod_signature(), 2482 &args, CHECK_(empty)); 2483 Handle mname(THREAD, (oop) result.get_jobject()); 2484 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2485 } 2486 2487 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2488 // We must ensure that all class loaders everywhere will reach this class, for any client. 2489 // This is a safe bet for public classes in java.lang, such as Object and String. 2490 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2491 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2492 static bool is_always_visible_class(oop mirror) { 2493 Klass* klass = java_lang_Class::as_Klass(mirror); 2494 if (klass->is_objArray_klass()) { 2495 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2496 } 2497 if (klass->is_typeArray_klass()) { 2498 return true; // primitive array 2499 } 2500 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2501 return klass->is_public() && 2502 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2503 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2504 } 2505 2506 2507 // Return the Java mirror (java.lang.Class instance) for a single-character 2508 // descriptor. This result, when available, is the same as produced by the 2509 // heavier API point of the same name that takes a Symbol. 2510 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2511 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2512 } 2513 2514 // Find or construct the Java mirror (java.lang.Class instance) for a 2515 // for the given field type signature, as interpreted relative to the 2516 // given class loader. Handles primitives, void, references, arrays, 2517 // and all other reflectable types, except method types. 2518 // N.B. Code in reflection should use this entry point. 2519 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2520 Klass* accessing_klass, 2521 Handle class_loader, 2522 Handle protection_domain, 2523 SignatureStream::FailureMode failure_mode, 2524 TRAPS) { 2525 Handle empty; 2526 2527 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2528 "one or the other, or perhaps neither"); 2529 2530 Symbol* type = signature; 2531 2532 // What we have here must be a valid field descriptor, 2533 // and all valid field descriptors are supported. 2534 // Produce the same java.lang.Class that reflection reports. 2535 if (type->utf8_length() == 1) { 2536 2537 // It's a primitive. (Void has a primitive mirror too.) 2538 char ch = type->char_at(0); 2539 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2540 return Handle(THREAD, find_java_mirror_for_type(ch)); 2541 2542 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2543 2544 // It's a reference type. 2545 if (accessing_klass != NULL) { 2546 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2547 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2548 } 2549 Klass* constant_type_klass; 2550 if (failure_mode == SignatureStream::ReturnNull) { 2551 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2552 CHECK_(empty)); 2553 } else { 2554 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2555 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2556 throw_error, CHECK_(empty)); 2557 } 2558 if (constant_type_klass == NULL) { 2559 return Handle(); // report failure this way 2560 } 2561 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2562 2563 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2564 if (accessing_klass != NULL) { 2565 Klass* sel_klass = constant_type_klass; 2566 bool fold_type_to_class = true; 2567 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2568 fold_type_to_class, CHECK_(empty)); 2569 } 2570 2571 return mirror; 2572 2573 } 2574 2575 // Fall through to an error. 2576 assert(false, "unsupported mirror syntax"); 2577 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2578 } 2579 2580 2581 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2582 // signature, as interpreted relative to the given class loader. 2583 // Because of class loader constraints, all method handle usage must be 2584 // consistent with this loader. 2585 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2586 Klass* accessing_klass, 2587 TRAPS) { 2588 Handle empty; 2589 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2590 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2591 int index = invoke_method_table()->hash_to_index(hash); 2592 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2593 if (spe != NULL && spe->method_type() != NULL) { 2594 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2595 return Handle(THREAD, spe->method_type()); 2596 } else if (!THREAD->can_call_java()) { 2597 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2598 return Handle(); // do not attempt from within compiler, unless it was cached 2599 } 2600 2601 Handle class_loader, protection_domain; 2602 if (accessing_klass != NULL) { 2603 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2604 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2605 } 2606 bool can_be_cached = true; 2607 int npts = ArgumentCount(signature).size(); 2608 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2609 int arg = 0; 2610 Handle rt; // the return type from the signature 2611 ResourceMark rm(THREAD); 2612 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2613 oop mirror = NULL; 2614 if (can_be_cached) { 2615 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2616 mirror = ss.as_java_mirror(Handle(), Handle(), 2617 SignatureStream::ReturnNull, CHECK_(empty)); 2618 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2619 // Fall back to accessing_klass context. 2620 can_be_cached = false; 2621 } 2622 } 2623 if (!can_be_cached) { 2624 // Resolve, throwing a real error if it doesn't work. 2625 mirror = ss.as_java_mirror(class_loader, protection_domain, 2626 SignatureStream::NCDFError, CHECK_(empty)); 2627 } 2628 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string()); 2629 if (ss.at_return_type()) 2630 rt = Handle(THREAD, mirror); 2631 else 2632 pts->obj_at_put(arg++, mirror); 2633 2634 // Check accessibility. 2635 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2636 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2637 mirror = NULL; // safety 2638 // Emulate ConstantPool::verify_constant_pool_resolve. 2639 bool fold_type_to_class = true; 2640 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2641 fold_type_to_class, CHECK_(empty)); 2642 } 2643 } 2644 assert(arg == npts, ""); 2645 2646 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2647 JavaCallArguments args(Handle(THREAD, rt())); 2648 args.push_oop(pts); 2649 JavaValue result(T_OBJECT); 2650 JavaCalls::call_static(&result, 2651 SystemDictionary::MethodHandleNatives_klass(), 2652 vmSymbols::findMethodHandleType_name(), 2653 vmSymbols::findMethodHandleType_signature(), 2654 &args, CHECK_(empty)); 2655 Handle method_type(THREAD, (oop) result.get_jobject()); 2656 2657 if (can_be_cached) { 2658 // We can cache this MethodType inside the JVM. 2659 MutexLocker ml(SystemDictionary_lock, THREAD); 2660 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2661 if (spe == NULL) 2662 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2663 if (spe->method_type() == NULL) { 2664 spe->set_method_type(method_type()); 2665 } 2666 } 2667 2668 // report back to the caller with the MethodType 2669 return method_type; 2670 } 2671 2672 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2673 Klass* accessing_klass, 2674 TRAPS) { 2675 Handle empty; 2676 ResourceMark rm(THREAD); 2677 SignatureStream ss(signature, /*is_method=*/ false); 2678 if (!ss.is_done()) { 2679 Handle class_loader, protection_domain; 2680 if (accessing_klass != NULL) { 2681 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2682 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2683 } 2684 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2685 ss.next(); 2686 if (ss.is_done()) { 2687 return Handle(THREAD, mirror); 2688 } 2689 } 2690 return empty; 2691 } 2692 2693 // Ask Java code to find or construct a method handle constant. 2694 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2695 int ref_kind, //e.g., JVM_REF_invokeVirtual 2696 Klass* callee, 2697 Symbol* name, 2698 Symbol* signature, 2699 TRAPS) { 2700 Handle empty; 2701 if (caller == NULL) { 2702 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2703 } 2704 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2705 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2706 2707 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2708 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2709 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2710 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2711 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2712 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2713 2714 if (ref_kind == JVM_REF_invokeVirtual && 2715 MethodHandles::is_signature_polymorphic_public_name(callee, name)) { 2716 // Skip resolution for public signature polymorphic methods such as 2717 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle 2718 // They require appendix argument which MemberName resolution doesn't handle. 2719 // There's special logic on JDK side to handle them 2720 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2721 } else { 2722 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); 2723 } 2724 2725 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2726 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2727 2728 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2729 JavaCallArguments args; 2730 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2731 args.push_int(ref_kind); 2732 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2733 args.push_oop(name_str); 2734 args.push_oop(type); 2735 JavaValue result(T_OBJECT); 2736 JavaCalls::call_static(&result, 2737 SystemDictionary::MethodHandleNatives_klass(), 2738 vmSymbols::linkMethodHandleConstant_name(), 2739 vmSymbols::linkMethodHandleConstant_signature(), 2740 &args, CHECK_(empty)); 2741 return Handle(THREAD, (oop) result.get_jobject()); 2742 } 2743 2744 // Ask Java to run a bootstrap method, in order to create a dynamic call site 2745 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry 2746 // with linkage results being stored back into the bootstrap specifier. 2747 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) { 2748 // Resolve the bootstrap specifier, its name, type, and static arguments 2749 bootstrap_specifier.resolve_bsm(CHECK); 2750 2751 // This should not happen. JDK code should take care of that. 2752 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) { 2753 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument"); 2754 } 2755 2756 bool is_indy = bootstrap_specifier.is_method_call(); 2757 objArrayHandle appendix_box; 2758 if (is_indy) { 2759 // Some method calls may require an appendix argument. Arrange to receive it. 2760 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK); 2761 assert(appendix_box->obj_at(0) == NULL, ""); 2762 } 2763 2764 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info) 2765 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2766 JavaCallArguments args; 2767 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror())); 2768 args.push_int(bootstrap_specifier.bss_index()); 2769 args.push_oop(bootstrap_specifier.bsm()); 2770 args.push_oop(bootstrap_specifier.name_arg()); 2771 args.push_oop(bootstrap_specifier.type_arg()); 2772 args.push_oop(bootstrap_specifier.arg_values()); 2773 if (is_indy) { 2774 args.push_oop(appendix_box); 2775 } 2776 JavaValue result(T_OBJECT); 2777 JavaCalls::call_static(&result, 2778 SystemDictionary::MethodHandleNatives_klass(), 2779 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(), 2780 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(), 2781 &args, CHECK); 2782 2783 Handle value(THREAD, (oop) result.get_jobject()); 2784 if (is_indy) { 2785 Handle appendix; 2786 methodHandle method = unpack_method_and_appendix(value, 2787 bootstrap_specifier.caller(), 2788 appendix_box, 2789 &appendix, CHECK); 2790 bootstrap_specifier.set_resolved_method(method, appendix); 2791 } else { 2792 bootstrap_specifier.set_resolved_value(value); 2793 } 2794 2795 // sanity check 2796 assert(bootstrap_specifier.is_resolved() || 2797 (bootstrap_specifier.is_method_call() && 2798 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed"); 2799 } 2800 2801 // Protection domain cache table handling 2802 2803 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2804 return _pd_cache_table->get(protection_domain); 2805 } 2806 2807 // ---------------------------------------------------------------------------- 2808 2809 void SystemDictionary::print_on(outputStream *st) { 2810 CDS_ONLY(SystemDictionaryShared::print_on(st)); 2811 GCMutexLocker mu(SystemDictionary_lock); 2812 2813 ClassLoaderDataGraph::print_dictionary(st); 2814 2815 // Placeholders 2816 placeholders()->print_on(st); 2817 st->cr(); 2818 2819 // loader constraints - print under SD_lock 2820 constraints()->print_on(st); 2821 st->cr(); 2822 2823 _pd_cache_table->print_on(st); 2824 st->cr(); 2825 } 2826 2827 void SystemDictionary::print() { print_on(tty); } 2828 2829 void SystemDictionary::verify() { 2830 guarantee(constraints() != NULL, 2831 "Verify of loader constraints failed"); 2832 guarantee(placeholders()->number_of_entries() >= 0, 2833 "Verify of placeholders failed"); 2834 2835 GCMutexLocker mu(SystemDictionary_lock); 2836 2837 // Verify dictionary 2838 ClassLoaderDataGraph::verify_dictionary(); 2839 2840 placeholders()->verify(); 2841 2842 // Verify constraint table 2843 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2844 constraints()->verify(placeholders()); 2845 2846 _pd_cache_table->verify(); 2847 } 2848 2849 void SystemDictionary::dump(outputStream *st, bool verbose) { 2850 assert_locked_or_safepoint(SystemDictionary_lock); 2851 if (verbose) { 2852 print_on(st); 2853 } else { 2854 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st)); 2855 ClassLoaderDataGraph::print_table_statistics(st); 2856 placeholders()->print_table_statistics(st, "Placeholder Table"); 2857 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 2858 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table"); 2859 } 2860 } 2861 2862 TableStatistics SystemDictionary::placeholders_statistics() { 2863 MutexLocker ml(SystemDictionary_lock); 2864 return placeholders()->statistics_calculate(); 2865 } 2866 2867 TableStatistics SystemDictionary::loader_constraints_statistics() { 2868 MutexLocker ml(SystemDictionary_lock); 2869 return constraints()->statistics_calculate(); 2870 } 2871 2872 TableStatistics SystemDictionary::protection_domain_cache_statistics() { 2873 MutexLocker ml(SystemDictionary_lock); 2874 return pd_cache_table()->statistics_calculate(); 2875 } 2876 2877 // Utility for dumping dictionaries. 2878 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 2879 DCmdWithParser(output, heap), 2880 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 2881 "BOOLEAN", false, "false") { 2882 _dcmdparser.add_dcmd_option(&_verbose); 2883 } 2884 2885 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 2886 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 2887 _verbose.value()); 2888 VMThread::execute(&dumper); 2889 } 2890 2891 int SystemDictionaryDCmd::num_arguments() { 2892 ResourceMark rm; 2893 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 2894 if (dcmd != NULL) { 2895 DCmdMark mark(dcmd); 2896 return dcmd->_dcmdparser.num_arguments(); 2897 } else { 2898 return 0; 2899 } 2900 }