1 /* 2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "jvm.h" 27 #include "aot/aotLoader.hpp" 28 #include "classfile/classFileParser.hpp" 29 #include "classfile/classFileStream.hpp" 30 #include "classfile/classLoader.hpp" 31 #include "classfile/classLoaderData.inline.hpp" 32 #include "classfile/classLoaderExt.hpp" 33 #include "classfile/dictionary.hpp" 34 #include "classfile/javaClasses.inline.hpp" 35 #include "classfile/klassFactory.hpp" 36 #include "classfile/loaderConstraints.hpp" 37 #include "classfile/packageEntry.hpp" 38 #include "classfile/placeholders.hpp" 39 #include "classfile/protectionDomainCache.hpp" 40 #include "classfile/resolutionErrors.hpp" 41 #include "classfile/stringTable.hpp" 42 #include "classfile/systemDictionary.hpp" 43 #include "classfile/vmSymbols.hpp" 44 #include "code/codeCache.hpp" 45 #include "compiler/compileBroker.hpp" 46 #include "gc/shared/gcLocker.hpp" 47 #include "gc/shared/gcTraceTime.inline.hpp" 48 #include "interpreter/bytecodeStream.hpp" 49 #include "interpreter/interpreter.hpp" 50 #include "logging/log.hpp" 51 #include "logging/logStream.hpp" 52 #include "memory/filemap.hpp" 53 #include "memory/metaspaceClosure.hpp" 54 #include "memory/oopFactory.hpp" 55 #include "memory/resourceArea.hpp" 56 #include "oops/instanceKlass.hpp" 57 #include "oops/instanceRefKlass.hpp" 58 #include "oops/klass.inline.hpp" 59 #include "oops/methodData.hpp" 60 #include "oops/objArrayKlass.hpp" 61 #include "oops/objArrayOop.inline.hpp" 62 #include "oops/oop.inline.hpp" 63 #include "oops/symbol.hpp" 64 #include "oops/typeArrayKlass.hpp" 65 #include "prims/jvmtiEnvBase.hpp" 66 #include "prims/resolvedMethodTable.hpp" 67 #include "prims/methodHandles.hpp" 68 #include "runtime/arguments.hpp" 69 #include "runtime/arguments_ext.hpp" 70 #include "runtime/biasedLocking.hpp" 71 #include "runtime/fieldType.hpp" 72 #include "runtime/handles.inline.hpp" 73 #include "runtime/java.hpp" 74 #include "runtime/javaCalls.hpp" 75 #include "runtime/mutexLocker.hpp" 76 #include "runtime/orderAccess.inline.hpp" 77 #include "runtime/signature.hpp" 78 #include "services/classLoadingService.hpp" 79 #include "services/diagnosticCommand.hpp" 80 #include "services/threadService.hpp" 81 #include "trace/tracing.hpp" 82 #include "utilities/macros.hpp" 83 #if INCLUDE_CDS 84 #include "classfile/sharedClassUtil.hpp" 85 #include "classfile/systemDictionaryShared.hpp" 86 #endif 87 #if INCLUDE_JVMCI 88 #include "jvmci/jvmciRuntime.hpp" 89 #endif 90 91 PlaceholderTable* SystemDictionary::_placeholders = NULL; 92 Dictionary* SystemDictionary::_shared_dictionary = NULL; 93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; 97 98 int SystemDictionary::_number_of_modifications = 0; 99 oop SystemDictionary::_system_loader_lock_obj = NULL; 100 101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 102 = { NULL /*, NULL...*/ }; 103 104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 105 106 oop SystemDictionary::_java_system_loader = NULL; 107 oop SystemDictionary::_java_platform_loader = NULL; 108 109 bool SystemDictionary::_has_checkPackageAccess = false; 110 111 // lazily initialized klass variables 112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 113 114 // Default ProtectionDomainCacheSize value 115 116 const int defaultProtectionDomainCacheSize = 1009; 117 118 119 // ---------------------------------------------------------------------------- 120 // Java-level SystemLoader and PlatformLoader 121 122 oop SystemDictionary::java_system_loader() { 123 return _java_system_loader; 124 } 125 126 oop SystemDictionary::java_platform_loader() { 127 return _java_platform_loader; 128 } 129 130 void SystemDictionary::compute_java_loaders(TRAPS) { 131 JavaValue result(T_OBJECT); 132 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); 133 JavaCalls::call_static(&result, 134 class_loader_klass, 135 vmSymbols::getSystemClassLoader_name(), 136 vmSymbols::void_classloader_signature(), 137 CHECK); 138 139 _java_system_loader = (oop)result.get_jobject(); 140 141 JavaCalls::call_static(&result, 142 class_loader_klass, 143 vmSymbols::getPlatformClassLoader_name(), 144 vmSymbols::void_classloader_signature(), 145 CHECK); 146 147 _java_platform_loader = (oop)result.get_jobject(); 148 149 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) 150 } 151 152 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 153 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 154 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD); 155 } 156 157 // ---------------------------------------------------------------------------- 158 // Parallel class loading check 159 160 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 161 if (class_loader.is_null()) return true; 162 if (AlwaysLockClassLoader) return false; 163 return java_lang_ClassLoader::parallelCapable(class_loader()); 164 } 165 // ---------------------------------------------------------------------------- 166 // ParallelDefineClass flag does not apply to bootclass loader 167 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 168 if (class_loader.is_null()) return false; 169 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 170 return true; 171 } 172 return false; 173 } 174 175 // Returns true if the passed class loader is the builtin application class loader 176 // or a custom system class loader. A customer system class loader can be 177 // specified via -Djava.system.class.loader. 178 bool SystemDictionary::is_system_class_loader(oop class_loader) { 179 if (class_loader == NULL) { 180 return false; 181 } 182 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 183 class_loader == _java_system_loader); 184 } 185 186 // Returns true if the passed class loader is the platform class loader. 187 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 188 if (class_loader == NULL) { 189 return false; 190 } 191 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 192 } 193 194 // ---------------------------------------------------------------------------- 195 // Resolving of classes 196 197 // Forwards to resolve_or_null 198 199 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 200 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 201 if (HAS_PENDING_EXCEPTION || klass == NULL) { 202 // can return a null klass 203 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 204 } 205 return klass; 206 } 207 208 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 209 bool throw_error, 210 Klass* klass, TRAPS) { 211 if (HAS_PENDING_EXCEPTION) { 212 // If we have a pending exception we forward it to the caller, unless throw_error is true, 213 // in which case we have to check whether the pending exception is a ClassNotFoundException, 214 // and if so convert it to a NoClassDefFoundError 215 // And chain the original ClassNotFoundException 216 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 217 ResourceMark rm(THREAD); 218 assert(klass == NULL, "Should not have result with exception pending"); 219 Handle e(THREAD, PENDING_EXCEPTION); 220 CLEAR_PENDING_EXCEPTION; 221 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 222 } else { 223 return NULL; 224 } 225 } 226 // Class not found, throw appropriate error or exception depending on value of throw_error 227 if (klass == NULL) { 228 ResourceMark rm(THREAD); 229 if (throw_error) { 230 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 231 } else { 232 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 233 } 234 } 235 return klass; 236 } 237 238 239 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 240 bool throw_error, TRAPS) 241 { 242 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 243 } 244 245 246 // Forwards to resolve_instance_class_or_null 247 248 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 249 assert(THREAD->can_call_java(), 250 "can not load classes with compiler thread: class=%s, classloader=%s", 251 class_name->as_C_string(), 252 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 253 if (FieldType::is_array(class_name)) { 254 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 255 } else if (FieldType::is_obj(class_name)) { 256 ResourceMark rm(THREAD); 257 // Ignore wrapping L and ;. 258 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 259 class_name->utf8_length() - 2, CHECK_NULL); 260 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 261 } else { 262 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 263 } 264 } 265 266 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 267 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 268 } 269 270 // Forwards to resolve_instance_class_or_null 271 272 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 273 Handle class_loader, 274 Handle protection_domain, 275 TRAPS) { 276 assert(FieldType::is_array(class_name), "must be array"); 277 Klass* k = NULL; 278 FieldArrayInfo fd; 279 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 280 // of this call 281 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 282 if (t == T_OBJECT) { 283 // naked oop "k" is OK here -- we assign back into it 284 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 285 class_loader, 286 protection_domain, 287 CHECK_NULL); 288 if (k != NULL) { 289 k = k->array_klass(fd.dimension(), CHECK_NULL); 290 } 291 } else { 292 k = Universe::typeArrayKlassObj(t); 293 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 294 } 295 return k; 296 } 297 298 299 // Must be called for any super-class or super-interface resolution 300 // during class definition to allow class circularity checking 301 // super-interface callers: 302 // parse_interfaces - for defineClass & jvmtiRedefineClasses 303 // super-class callers: 304 // ClassFileParser - for defineClass & jvmtiRedefineClasses 305 // load_shared_class - while loading a class from shared archive 306 // resolve_instance_class_or_null: 307 // via: handle_parallel_super_load 308 // when resolving a class that has an existing placeholder with 309 // a saved superclass [i.e. a defineClass is currently in progress] 310 // if another thread is trying to resolve the class, it must do 311 // super-class checks on its own thread to catch class circularity 312 // This last call is critical in class circularity checking for cases 313 // where classloading is delegated to different threads and the 314 // classloader lock is released. 315 // Take the case: Base->Super->Base 316 // 1. If thread T1 tries to do a defineClass of class Base 317 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 318 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 319 // so it tries to load Super 320 // 3. If we load the class internally, or user classloader uses same thread 321 // loadClassFromxxx or defineClass via parseClassFile Super ... 322 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 323 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 324 // 3.4 calls resolve_super_or_fail Base 325 // 3.5 finds T1,Base -> throws class circularity 326 //OR 4. If T2 tries to resolve Super via defineClass Super ... 327 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 328 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 329 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 330 // 4.4 finds T2, Super -> throws class circularity 331 // Must be called, even if superclass is null, since this is 332 // where the placeholder entry is created which claims this 333 // thread is loading this class/classloader. 334 // Be careful when modifying this code: once you have run 335 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 336 // you need to find_and_remove it before returning. 337 // So be careful to not exit with a CHECK_ macro betweeen these calls. 338 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 339 Symbol* class_name, 340 Handle class_loader, 341 Handle protection_domain, 342 bool is_superclass, 343 TRAPS) { 344 #if INCLUDE_CDS 345 if (DumpSharedSpaces) { 346 // Special processing for CDS dump time. 347 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 348 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 349 if (k) { 350 return k; 351 } 352 } 353 #endif // INCLUDE_CDS 354 355 // Double-check, if child class is already loaded, just return super-class,interface 356 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 357 // dictionary. 358 // Make sure there's a placeholder for the *child* before resolving. 359 // Used as a claim that this thread is currently loading superclass/classloader 360 // Used here for ClassCircularity checks and also for heap verification 361 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 362 // Must check ClassCircularity before checking if super class is already loaded. 363 // 364 // We might not already have a placeholder if this child_name was 365 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 366 // the name of the class might not be known until the stream is actually 367 // parsed. 368 // Bugs 4643874, 4715493 369 370 ClassLoaderData* loader_data = class_loader_data(class_loader); 371 Dictionary* dictionary = loader_data->dictionary(); 372 unsigned int d_hash = dictionary->compute_hash(child_name); 373 unsigned int p_hash = placeholders()->compute_hash(child_name); 374 int p_index = placeholders()->hash_to_index(p_hash); 375 // can't throw error holding a lock 376 bool child_already_loaded = false; 377 bool throw_circularity_error = false; 378 { 379 MutexLocker mu(SystemDictionary_lock, THREAD); 380 Klass* childk = find_class(d_hash, child_name, dictionary); 381 Klass* quicksuperk; 382 // to support // loading: if child done loading, just return superclass 383 // if class_name, & class_loader don't match: 384 // if initial define, SD update will give LinkageError 385 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 386 // so we don't throw an exception here. 387 // see: nsk redefclass014 & java.lang.instrument Instrument032 388 if ((childk != NULL ) && (is_superclass) && 389 ((quicksuperk = childk->super()) != NULL) && 390 391 ((quicksuperk->name() == class_name) && 392 (quicksuperk->class_loader() == class_loader()))) { 393 return quicksuperk; 394 } else { 395 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 396 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 397 throw_circularity_error = true; 398 } 399 } 400 if (!throw_circularity_error) { 401 // Be careful not to exit resolve_super 402 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 403 } 404 } 405 if (throw_circularity_error) { 406 ResourceMark rm(THREAD); 407 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 408 } 409 410 // java.lang.Object should have been found above 411 assert(class_name != NULL, "null super class for resolving"); 412 // Resolve the super class or interface, check results on return 413 Klass* superk = SystemDictionary::resolve_or_null(class_name, 414 class_loader, 415 protection_domain, 416 THREAD); 417 418 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 419 // It is no longer necessary to keep the placeholder table alive until update_dictionary 420 // or error. GC used to walk the placeholder table as strong roots. 421 // The instanceKlass is kept alive because the class loader is on the stack, 422 // which keeps the loader_data alive, as well as all instanceKlasses in 423 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 424 { 425 MutexLocker mu(SystemDictionary_lock, THREAD); 426 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 427 SystemDictionary_lock->notify_all(); 428 } 429 if (HAS_PENDING_EXCEPTION || superk == NULL) { 430 // can null superk 431 superk = handle_resolution_exception(class_name, true, superk, THREAD); 432 } 433 434 return superk; 435 } 436 437 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 438 Handle class_loader, 439 Handle protection_domain, 440 TRAPS) { 441 if(!has_checkPackageAccess()) return; 442 443 // Now we have to call back to java to check if the initating class has access 444 JavaValue result(T_VOID); 445 LogTarget(Debug, protectiondomain) lt; 446 if (lt.is_enabled()) { 447 ResourceMark rm; 448 // Print out trace information 449 LogStream ls(lt); 450 ls.print_cr("Checking package access"); 451 ls.print("class loader: "); class_loader()->print_value_on(&ls); 452 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls); 453 ls.print(" loading: "); klass->print_value_on(&ls); 454 ls.cr(); 455 } 456 457 // This handle and the class_loader handle passed in keeps this class from 458 // being unloaded through several GC points. 459 // The class_loader handle passed in is the initiating loader. 460 Handle mirror(THREAD, klass->java_mirror()); 461 462 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 463 JavaCalls::call_special(&result, 464 class_loader, 465 system_loader, 466 vmSymbols::checkPackageAccess_name(), 467 vmSymbols::class_protectiondomain_signature(), 468 mirror, 469 protection_domain, 470 THREAD); 471 472 if (HAS_PENDING_EXCEPTION) { 473 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 474 } else { 475 log_debug(protectiondomain)("granted"); 476 } 477 478 if (HAS_PENDING_EXCEPTION) return; 479 480 // If no exception has been thrown, we have validated the protection domain 481 // Insert the protection domain of the initiating class into the set. 482 { 483 ClassLoaderData* loader_data = class_loader_data(class_loader); 484 Dictionary* dictionary = loader_data->dictionary(); 485 486 Symbol* kn = klass->name(); 487 unsigned int d_hash = dictionary->compute_hash(kn); 488 489 MutexLocker mu(SystemDictionary_lock, THREAD); 490 int d_index = dictionary->hash_to_index(d_hash); 491 dictionary->add_protection_domain(d_index, d_hash, klass, 492 protection_domain, THREAD); 493 } 494 } 495 496 // We only get here if this thread finds that another thread 497 // has already claimed the placeholder token for the current operation, 498 // but that other thread either never owned or gave up the 499 // object lock 500 // Waits on SystemDictionary_lock to indicate placeholder table updated 501 // On return, caller must recheck placeholder table state 502 // 503 // We only get here if 504 // 1) custom classLoader, i.e. not bootstrap classloader 505 // 2) custom classLoader has broken the class loader objectLock 506 // so another thread got here in parallel 507 // 508 // lockObject must be held. 509 // Complicated dance due to lock ordering: 510 // Must first release the classloader object lock to 511 // allow initial definer to complete the class definition 512 // and to avoid deadlock 513 // Reclaim classloader lock object with same original recursion count 514 // Must release SystemDictionary_lock after notify, since 515 // class loader lock must be claimed before SystemDictionary_lock 516 // to prevent deadlocks 517 // 518 // The notify allows applications that did an untimed wait() on 519 // the classloader object lock to not hang. 520 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 521 assert_lock_strong(SystemDictionary_lock); 522 523 bool calledholdinglock 524 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 525 assert(calledholdinglock,"must hold lock for notify"); 526 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 527 ObjectSynchronizer::notifyall(lockObject, THREAD); 528 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 529 SystemDictionary_lock->wait(); 530 SystemDictionary_lock->unlock(); 531 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 532 SystemDictionary_lock->lock(); 533 } 534 535 // If the class in is in the placeholder table, class loading is in progress 536 // For cases where the application changes threads to load classes, it 537 // is critical to ClassCircularity detection that we try loading 538 // the superclass on the same thread internally, so we do parallel 539 // super class loading here. 540 // This also is critical in cases where the original thread gets stalled 541 // even in non-circularity situations. 542 // Note: must call resolve_super_or_fail even if null super - 543 // to force placeholder entry creation for this class for circularity detection 544 // Caller must check for pending exception 545 // Returns non-null Klass* if other thread has completed load 546 // and we are done, 547 // If return null Klass* and no pending exception, the caller must load the class 548 InstanceKlass* SystemDictionary::handle_parallel_super_load( 549 Symbol* name, Symbol* superclassname, Handle class_loader, 550 Handle protection_domain, Handle lockObject, TRAPS) { 551 552 ClassLoaderData* loader_data = class_loader_data(class_loader); 553 Dictionary* dictionary = loader_data->dictionary(); 554 unsigned int d_hash = dictionary->compute_hash(name); 555 unsigned int p_hash = placeholders()->compute_hash(name); 556 int p_index = placeholders()->hash_to_index(p_hash); 557 558 // superk is not used, resolve_super called for circularity check only 559 // This code is reached in two situations. One if this thread 560 // is loading the same class twice (e.g. ClassCircularity, or 561 // java.lang.instrument). 562 // The second is if another thread started the resolve_super first 563 // and has not yet finished. 564 // In both cases the original caller will clean up the placeholder 565 // entry on error. 566 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 567 superclassname, 568 class_loader, 569 protection_domain, 570 true, 571 CHECK_NULL); 572 573 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 574 // Serial class loaders and bootstrap classloader do wait for superclass loads 575 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 576 MutexLocker mu(SystemDictionary_lock, THREAD); 577 // Check if classloading completed while we were loading superclass or waiting 578 return find_class(d_hash, name, dictionary); 579 } 580 581 // must loop to both handle other placeholder updates 582 // and spurious notifications 583 bool super_load_in_progress = true; 584 PlaceholderEntry* placeholder; 585 while (super_load_in_progress) { 586 MutexLocker mu(SystemDictionary_lock, THREAD); 587 // Check if classloading completed while we were loading superclass or waiting 588 InstanceKlass* check = find_class(d_hash, name, dictionary); 589 if (check != NULL) { 590 // Klass is already loaded, so just return it 591 return check; 592 } else { 593 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 594 if (placeholder && placeholder->super_load_in_progress() ){ 595 // We only get here if the application has released the 596 // classloader lock when another thread was in the middle of loading a 597 // superclass/superinterface for this class, and now 598 // this thread is also trying to load this class. 599 // To minimize surprises, the first thread that started to 600 // load a class should be the one to complete the loading 601 // with the classfile it initially expected. 602 // This logic has the current thread wait once it has done 603 // all the superclass/superinterface loading it can, until 604 // the original thread completes the class loading or fails 605 // If it completes we will use the resulting InstanceKlass 606 // which we will find below in the systemDictionary. 607 // We also get here for parallel bootstrap classloader 608 if (class_loader.is_null()) { 609 SystemDictionary_lock->wait(); 610 } else { 611 double_lock_wait(lockObject, THREAD); 612 } 613 } else { 614 // If not in SD and not in PH, other thread's load must have failed 615 super_load_in_progress = false; 616 } 617 } 618 } 619 return NULL; 620 } 621 622 static void post_class_load_event(EventClassLoad* event, 623 const InstanceKlass* k, 624 const ClassLoaderData* init_cld) { 625 #if INCLUDE_TRACE 626 assert(event != NULL, "invariant"); 627 assert(k != NULL, "invariant"); 628 if (event->should_commit()) { 629 event->set_loadedClass(k); 630 event->set_definingClassLoader(k->class_loader_data()); 631 event->set_initiatingClassLoader(init_cld); 632 event->commit(); 633 } 634 #endif // INCLUDE_TRACE 635 } 636 637 static void class_define_event(InstanceKlass* k, 638 const ClassLoaderData* def_cld) { 639 #if INCLUDE_TRACE 640 EventClassDefine event; 641 if (event.should_commit()) { 642 event.set_definedClass(k); 643 event.set_definingClassLoader(def_cld); 644 event.commit(); 645 } 646 #endif // INCLUDE_TRACE 647 } 648 649 // Be careful when modifying this code: once you have run 650 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 651 // you need to find_and_remove it before returning. 652 // So be careful to not exit with a CHECK_ macro betweeen these calls. 653 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 654 Handle class_loader, 655 Handle protection_domain, 656 TRAPS) { 657 assert(name != NULL && !FieldType::is_array(name) && 658 !FieldType::is_obj(name), "invalid class name"); 659 660 EventClassLoad class_load_start_event; 661 662 HandleMark hm(THREAD); 663 664 // Fix for 4474172; see evaluation for more details 665 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 666 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 667 Dictionary* dictionary = loader_data->dictionary(); 668 unsigned int d_hash = dictionary->compute_hash(name); 669 670 // Do lookup to see if class already exist and the protection domain 671 // has the right access 672 // This call uses find which checks protection domain already matches 673 // All subsequent calls use find_class, and set has_loaded_class so that 674 // before we return a result we call out to java to check for valid protection domain 675 // to allow returning the Klass* and add it to the pd_set if it is valid 676 { 677 Klass* probe = dictionary->find(d_hash, name, protection_domain); 678 if (probe != NULL) return probe; 679 } 680 681 // Non-bootstrap class loaders will call out to class loader and 682 // define via jvm/jni_DefineClass which will acquire the 683 // class loader object lock to protect against multiple threads 684 // defining the class in parallel by accident. 685 // This lock must be acquired here so the waiter will find 686 // any successful result in the SystemDictionary and not attempt 687 // the define. 688 // ParallelCapable Classloaders and the bootstrap classloader 689 // do not acquire lock here. 690 bool DoObjectLock = true; 691 if (is_parallelCapable(class_loader)) { 692 DoObjectLock = false; 693 } 694 695 unsigned int p_hash = placeholders()->compute_hash(name); 696 int p_index = placeholders()->hash_to_index(p_hash); 697 698 // Class is not in SystemDictionary so we have to do loading. 699 // Make sure we are synchronized on the class loader before we proceed 700 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 701 check_loader_lock_contention(lockObject, THREAD); 702 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 703 704 // Check again (after locking) if class already exist in SystemDictionary 705 bool class_has_been_loaded = false; 706 bool super_load_in_progress = false; 707 bool havesupername = false; 708 InstanceKlass* k = NULL; 709 PlaceholderEntry* placeholder; 710 Symbol* superclassname = NULL; 711 712 { 713 MutexLocker mu(SystemDictionary_lock, THREAD); 714 InstanceKlass* check = find_class(d_hash, name, dictionary); 715 if (check != NULL) { 716 // Klass is already loaded, so just return it 717 class_has_been_loaded = true; 718 k = check; 719 } else { 720 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 721 if (placeholder && placeholder->super_load_in_progress()) { 722 super_load_in_progress = true; 723 if (placeholder->havesupername() == true) { 724 superclassname = placeholder->supername(); 725 havesupername = true; 726 } 727 } 728 } 729 } 730 731 // If the class is in the placeholder table, class loading is in progress 732 if (super_load_in_progress && havesupername==true) { 733 k = handle_parallel_super_load(name, 734 superclassname, 735 class_loader, 736 protection_domain, 737 lockObject, THREAD); 738 if (HAS_PENDING_EXCEPTION) { 739 return NULL; 740 } 741 if (k != NULL) { 742 class_has_been_loaded = true; 743 } 744 } 745 746 bool throw_circularity_error = false; 747 if (!class_has_been_loaded) { 748 bool load_instance_added = false; 749 750 // add placeholder entry to record loading instance class 751 // Five cases: 752 // All cases need to prevent modifying bootclasssearchpath 753 // in parallel with a classload of same classname 754 // Redefineclasses uses existence of the placeholder for the duration 755 // of the class load to prevent concurrent redefinition of not completely 756 // defined classes. 757 // case 1. traditional classloaders that rely on the classloader object lock 758 // - no other need for LOAD_INSTANCE 759 // case 2. traditional classloaders that break the classloader object lock 760 // as a deadlock workaround. Detection of this case requires that 761 // this check is done while holding the classloader object lock, 762 // and that lock is still held when calling classloader's loadClass. 763 // For these classloaders, we ensure that the first requestor 764 // completes the load and other requestors wait for completion. 765 // case 3. Bootstrap classloader - don't own objectLocker 766 // This classloader supports parallelism at the classloader level, 767 // but only allows a single load of a class/classloader pair. 768 // No performance benefit and no deadlock issues. 769 // case 4. parallelCapable user level classloaders - without objectLocker 770 // Allow parallel classloading of a class/classloader pair 771 772 { 773 MutexLocker mu(SystemDictionary_lock, THREAD); 774 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 775 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 776 if (oldprobe) { 777 // only need check_seen_thread once, not on each loop 778 // 6341374 java/lang/Instrument with -Xcomp 779 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 780 throw_circularity_error = true; 781 } else { 782 // case 1: traditional: should never see load_in_progress. 783 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 784 785 // case 3: bootstrap classloader: prevent futile classloading, 786 // wait on first requestor 787 if (class_loader.is_null()) { 788 SystemDictionary_lock->wait(); 789 } else { 790 // case 2: traditional with broken classloader lock. wait on first 791 // requestor. 792 double_lock_wait(lockObject, THREAD); 793 } 794 // Check if classloading completed while we were waiting 795 InstanceKlass* check = find_class(d_hash, name, dictionary); 796 if (check != NULL) { 797 // Klass is already loaded, so just return it 798 k = check; 799 class_has_been_loaded = true; 800 } 801 // check if other thread failed to load and cleaned up 802 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 803 } 804 } 805 } 806 } 807 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 808 // case 4: parallelCapable: allow competing threads to try 809 // LOAD_INSTANCE in parallel 810 811 if (!throw_circularity_error && !class_has_been_loaded) { 812 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 813 load_instance_added = true; 814 // For class loaders that do not acquire the classloader object lock, 815 // if they did not catch another thread holding LOAD_INSTANCE, 816 // need a check analogous to the acquire ObjectLocker/find_class 817 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 818 // one final check if the load has already completed 819 // class loaders holding the ObjectLock shouldn't find the class here 820 InstanceKlass* check = find_class(d_hash, name, dictionary); 821 if (check != NULL) { 822 // Klass is already loaded, so return it after checking/adding protection domain 823 k = check; 824 class_has_been_loaded = true; 825 } 826 } 827 } 828 829 // must throw error outside of owning lock 830 if (throw_circularity_error) { 831 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 832 ResourceMark rm(THREAD); 833 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 834 } 835 836 if (!class_has_been_loaded) { 837 838 // Do actual loading 839 k = load_instance_class(name, class_loader, THREAD); 840 841 // If everything was OK (no exceptions, no null return value), and 842 // class_loader is NOT the defining loader, do a little more bookkeeping. 843 if (!HAS_PENDING_EXCEPTION && k != NULL && 844 k->class_loader() != class_loader()) { 845 846 check_constraints(d_hash, k, class_loader, false, THREAD); 847 848 // Need to check for a PENDING_EXCEPTION again; check_constraints 849 // can throw and doesn't use the CHECK macro. 850 if (!HAS_PENDING_EXCEPTION) { 851 { // Grabbing the Compile_lock prevents systemDictionary updates 852 // during compilations. 853 MutexLocker mu(Compile_lock, THREAD); 854 update_dictionary(d_hash, p_index, p_hash, 855 k, class_loader, THREAD); 856 } 857 858 if (JvmtiExport::should_post_class_load()) { 859 Thread *thread = THREAD; 860 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 861 JvmtiExport::post_class_load((JavaThread *) thread, k); 862 } 863 } 864 } 865 } // load_instance_class 866 867 if (load_instance_added == true) { 868 // clean up placeholder entries for LOAD_INSTANCE success or error 869 // This brackets the SystemDictionary updates for both defining 870 // and initiating loaders 871 MutexLocker mu(SystemDictionary_lock, THREAD); 872 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 873 SystemDictionary_lock->notify_all(); 874 } 875 } 876 877 if (HAS_PENDING_EXCEPTION || k == NULL) { 878 return NULL; 879 } 880 881 post_class_load_event(&class_load_start_event, k, loader_data); 882 883 #ifdef ASSERT 884 { 885 ClassLoaderData* loader_data = k->class_loader_data(); 886 MutexLocker mu(SystemDictionary_lock, THREAD); 887 Klass* kk = find_class(name, loader_data); 888 assert(kk == k, "should be present in dictionary"); 889 } 890 #endif 891 892 // return if the protection domain in NULL 893 if (protection_domain() == NULL) return k; 894 895 // Check the protection domain has the right access 896 if (dictionary->is_valid_protection_domain(d_hash, name, 897 protection_domain)) { 898 return k; 899 } 900 901 // Verify protection domain. If it fails an exception is thrown 902 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 903 904 return k; 905 } 906 907 908 // This routine does not lock the system dictionary. 909 // 910 // Since readers don't hold a lock, we must make sure that system 911 // dictionary entries are only removed at a safepoint (when only one 912 // thread is running), and are added to in a safe way (all links must 913 // be updated in an MT-safe manner). 914 // 915 // Callers should be aware that an entry could be added just after 916 // _dictionary->bucket(index) is read here, so the caller will not see 917 // the new entry. 918 919 Klass* SystemDictionary::find(Symbol* class_name, 920 Handle class_loader, 921 Handle protection_domain, 922 TRAPS) { 923 924 // The result of this call should be consistent with the result 925 // of the call to resolve_instance_class_or_null(). 926 // See evaluation 6790209 and 4474172 for more details. 927 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 928 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 929 930 if (loader_data == NULL) { 931 // If the ClassLoaderData has not been setup, 932 // then the class loader has no entries in the dictionary. 933 return NULL; 934 } 935 936 Dictionary* dictionary = loader_data->dictionary(); 937 unsigned int d_hash = dictionary->compute_hash(class_name); 938 return dictionary->find(d_hash, class_name, 939 protection_domain); 940 } 941 942 943 // Look for a loaded instance or array klass by name. Do not do any loading. 944 // return NULL in case of error. 945 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 946 Handle class_loader, 947 Handle protection_domain, 948 TRAPS) { 949 Klass* k = NULL; 950 assert(class_name != NULL, "class name must be non NULL"); 951 952 if (FieldType::is_array(class_name)) { 953 // The name refers to an array. Parse the name. 954 // dimension and object_key in FieldArrayInfo are assigned as a 955 // side-effect of this call 956 FieldArrayInfo fd; 957 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 958 if (t != T_OBJECT) { 959 k = Universe::typeArrayKlassObj(t); 960 } else { 961 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 962 } 963 if (k != NULL) { 964 k = k->array_klass_or_null(fd.dimension()); 965 } 966 } else { 967 k = find(class_name, class_loader, protection_domain, THREAD); 968 } 969 return k; 970 } 971 972 // Note: this method is much like resolve_from_stream, but 973 // does not publish the classes via the SystemDictionary. 974 // Handles unsafe_DefineAnonymousClass and redefineclasses 975 // RedefinedClasses do not add to the class hierarchy 976 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 977 Handle class_loader, 978 Handle protection_domain, 979 ClassFileStream* st, 980 const InstanceKlass* host_klass, 981 GrowableArray<Handle>* cp_patches, 982 TRAPS) { 983 984 EventClassLoad class_load_start_event; 985 986 ClassLoaderData* loader_data; 987 if (host_klass != NULL) { 988 // Create a new CLD for anonymous class, that uses the same class loader 989 // as the host_klass 990 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 991 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 992 } else { 993 loader_data = ClassLoaderData::class_loader_data(class_loader()); 994 } 995 996 assert(st != NULL, "invariant"); 997 assert(st->need_verify(), "invariant"); 998 999 // Parse stream and create a klass. 1000 // Note that we do this even though this klass might 1001 // already be present in the SystemDictionary, otherwise we would not 1002 // throw potential ClassFormatErrors. 1003 1004 InstanceKlass* k = KlassFactory::create_from_stream(st, 1005 class_name, 1006 loader_data, 1007 protection_domain, 1008 host_klass, 1009 cp_patches, 1010 CHECK_NULL); 1011 1012 if (host_klass != NULL && k != NULL) { 1013 // If it's anonymous, initialize it now, since nobody else will. 1014 1015 { 1016 MutexLocker mu_r(Compile_lock, THREAD); 1017 1018 // Add to class hierarchy, initialize vtables, and do possible 1019 // deoptimizations. 1020 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1021 1022 // But, do not add to dictionary. 1023 1024 // compiled code dependencies need to be validated anyway 1025 notice_modification(); 1026 } 1027 1028 // Rewrite and patch constant pool here. 1029 k->link_class(CHECK_NULL); 1030 if (cp_patches != NULL) { 1031 k->constants()->patch_resolved_references(cp_patches); 1032 } 1033 k->eager_initialize(CHECK_NULL); 1034 1035 // notify jvmti 1036 if (JvmtiExport::should_post_class_load()) { 1037 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1038 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1039 } 1040 1041 post_class_load_event(&class_load_start_event, k, loader_data); 1042 } 1043 assert(host_klass != NULL || NULL == cp_patches, 1044 "cp_patches only found with host_klass"); 1045 1046 return k; 1047 } 1048 1049 // Add a klass to the system from a stream (called by jni_DefineClass and 1050 // JVM_DefineClass). 1051 // Note: class_name can be NULL. In that case we do not know the name of 1052 // the class until we have parsed the stream. 1053 1054 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1055 Handle class_loader, 1056 Handle protection_domain, 1057 ClassFileStream* st, 1058 TRAPS) { 1059 #if INCLUDE_CDS 1060 ResourceMark rm(THREAD); 1061 if (DumpSharedSpaces && !class_loader.is_null() && 1062 !UseAppCDS && (strcmp(class_name->as_C_string(), "Unnamed") != 0) 1063 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed" 1064 // class, which is used by MethodHandles). 1065 #if INCLUDE_JVMCI 1066 // Need to define the class if force initialization of JVMCI runtime. Otherwise the <clinit> of the 1067 // JVMCI class will result in ClassNotFoundException. 1068 && !Arguments::is_force_init_jvmci_runtime()) { 1069 #else 1070 ) { 1071 #endif // INCLUDE_JVMCI 1072 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 1073 } 1074 #endif // INCLUDE_CDS 1075 1076 HandleMark hm(THREAD); 1077 1078 // Classloaders that support parallelism, e.g. bootstrap classloader, 1079 // do not acquire lock here 1080 bool DoObjectLock = true; 1081 if (is_parallelCapable(class_loader)) { 1082 DoObjectLock = false; 1083 } 1084 1085 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1086 1087 // Make sure we are synchronized on the class loader before we proceed 1088 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1089 check_loader_lock_contention(lockObject, THREAD); 1090 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1091 1092 assert(st != NULL, "invariant"); 1093 1094 // Parse the stream and create a klass. 1095 // Note that we do this even though this klass might 1096 // already be present in the SystemDictionary, otherwise we would not 1097 // throw potential ClassFormatErrors. 1098 InstanceKlass* k = NULL; 1099 1100 #if INCLUDE_CDS 1101 if (!DumpSharedSpaces) { 1102 k = SystemDictionaryShared::lookup_from_stream(class_name, 1103 class_loader, 1104 protection_domain, 1105 st, 1106 CHECK_NULL); 1107 } 1108 #endif 1109 1110 if (k == NULL) { 1111 if (st->buffer() == NULL) { 1112 return NULL; 1113 } 1114 k = KlassFactory::create_from_stream(st, 1115 class_name, 1116 loader_data, 1117 protection_domain, 1118 NULL, // host_klass 1119 NULL, // cp_patches 1120 CHECK_NULL); 1121 } 1122 1123 assert(k != NULL, "no klass created"); 1124 Symbol* h_name = k->name(); 1125 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1126 1127 // Add class just loaded 1128 // If a class loader supports parallel classloading handle parallel define requests 1129 // find_or_define_instance_class may return a different InstanceKlass 1130 if (is_parallelCapable(class_loader)) { 1131 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1132 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1133 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1134 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1135 loader_data->add_to_deallocate_list(k); 1136 k = defined_k; 1137 } 1138 } else { 1139 define_instance_class(k, THREAD); 1140 } 1141 1142 // If defining the class throws an exception register 'k' for cleanup. 1143 if (HAS_PENDING_EXCEPTION) { 1144 assert(k != NULL, "Must have an instance klass here!"); 1145 loader_data->add_to_deallocate_list(k); 1146 return NULL; 1147 } 1148 1149 // Make sure we have an entry in the SystemDictionary on success 1150 debug_only( { 1151 MutexLocker mu(SystemDictionary_lock, THREAD); 1152 1153 Klass* check = find_class(h_name, k->class_loader_data()); 1154 assert(check == k, "should be present in the dictionary"); 1155 } ); 1156 1157 return k; 1158 } 1159 1160 #if INCLUDE_CDS 1161 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1162 int number_of_entries) { 1163 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1164 "bad shared dictionary size."); 1165 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1166 _shared_dictionary_size, t, number_of_entries); 1167 } 1168 1169 1170 // If there is a shared dictionary, then find the entry for the 1171 // given shared system class, if any. 1172 1173 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1174 if (shared_dictionary() != NULL) { 1175 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1176 int d_index = shared_dictionary()->hash_to_index(d_hash); 1177 1178 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1179 } else { 1180 return NULL; 1181 } 1182 } 1183 1184 1185 // Load a class from the shared spaces (found through the shared system 1186 // dictionary). Force the superclass and all interfaces to be loaded. 1187 // Update the class definition to include sibling classes and no 1188 // subclasses (yet). [Classes in the shared space are not part of the 1189 // object hierarchy until loaded.] 1190 1191 InstanceKlass* SystemDictionary::load_shared_class( 1192 Symbol* class_name, Handle class_loader, TRAPS) { 1193 InstanceKlass* ik = find_shared_class(class_name); 1194 // Make sure we only return the boot class for the NULL classloader. 1195 if (ik != NULL && 1196 ik->is_shared_boot_class() && class_loader.is_null()) { 1197 Handle protection_domain; 1198 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1199 } 1200 return NULL; 1201 } 1202 1203 // Check if a shared class can be loaded by the specific classloader: 1204 // 1205 // NULL classloader: 1206 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1207 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1208 // be defined in an unnamed module. 1209 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1210 InstanceKlass* ik, 1211 Handle class_loader, TRAPS) { 1212 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1213 "Cannot use sharing if java.base is patched"); 1214 ResourceMark rm; 1215 int path_index = ik->shared_classpath_index(); 1216 ClassLoaderData* loader_data = class_loader_data(class_loader); 1217 if (path_index < 0) { 1218 // path_index < 0 indicates that the class is intended for a custom loader 1219 // and should not be loaded by boot/platform/app loaders 1220 if (loader_data->is_builtin_class_loader_data()) { 1221 return false; 1222 } else { 1223 return true; 1224 } 1225 } 1226 SharedClassPathEntry* ent = 1227 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index); 1228 if (!Universe::is_module_initialized()) { 1229 assert(ent != NULL && ent->is_modules_image(), 1230 "Loading non-bootstrap classes before the module system is initialized"); 1231 assert(class_loader.is_null(), "sanity"); 1232 return true; 1233 } 1234 // Get the pkg_entry from the classloader 1235 TempNewSymbol pkg_name = NULL; 1236 PackageEntry* pkg_entry = NULL; 1237 ModuleEntry* mod_entry = NULL; 1238 const char* pkg_string = NULL; 1239 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1240 if (pkg_name != NULL) { 1241 pkg_string = pkg_name->as_C_string(); 1242 if (loader_data != NULL) { 1243 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1244 } 1245 if (pkg_entry != NULL) { 1246 mod_entry = pkg_entry->module(); 1247 } 1248 } 1249 1250 // If the archived class is from a module that has been patched at runtime, 1251 // the class cannot be loaded from the archive. 1252 if (mod_entry != NULL && mod_entry->is_patched()) { 1253 return false; 1254 } 1255 1256 if (class_loader.is_null()) { 1257 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1258 // The NULL classloader can load archived class originated from the 1259 // "modules" jimage and the -Xbootclasspath/a. For class from the 1260 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1261 // by the NULL classloader. 1262 if (mod_entry != NULL) { 1263 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1264 // ModuleEntry's location agrees with the archived class' origination. 1265 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1266 return true; // Module class from the "module" jimage 1267 } 1268 } 1269 1270 // If the archived class is not from the "module" jimage, the class can be 1271 // loaded by the NULL classloader if 1272 // 1273 // 1. the class is from the unamed package 1274 // 2. or, the class is not from a module defined in the NULL classloader 1275 // 3. or, the class is from an unamed module 1276 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1277 // the class is from the -Xbootclasspath/a 1278 if (pkg_string == NULL || 1279 pkg_entry == NULL || 1280 pkg_entry->in_unnamed_module()) { 1281 assert(mod_entry == NULL || 1282 mod_entry == loader_data->unnamed_module(), 1283 "the unnamed module is not defined in the classloader"); 1284 return true; 1285 } 1286 } 1287 return false; 1288 } else { 1289 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1290 ik, class_loader, pkg_string, pkg_name, 1291 pkg_entry, mod_entry, CHECK_(false)); 1292 return res; 1293 } 1294 } 1295 1296 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1297 Handle class_loader, 1298 Handle protection_domain, TRAPS) { 1299 1300 if (ik != NULL) { 1301 Symbol* class_name = ik->name(); 1302 1303 bool visible = is_shared_class_visible( 1304 class_name, ik, class_loader, CHECK_NULL); 1305 if (!visible) { 1306 return NULL; 1307 } 1308 1309 // Resolve the superclass and interfaces. They must be the same 1310 // as in dump time, because the layout of <ik> depends on 1311 // the specific layout of ik->super() and ik->local_interfaces(). 1312 // 1313 // If unexpected superclass or interfaces are found, we cannot 1314 // load <ik> from the shared archive. 1315 1316 if (ik->super() != NULL) { 1317 Symbol* cn = ik->super()->name(); 1318 Klass *s = resolve_super_or_fail(class_name, cn, 1319 class_loader, protection_domain, true, CHECK_NULL); 1320 if (s != ik->super()) { 1321 // The dynamically resolved super class is not the same as the one we used during dump time, 1322 // so we cannot use ik. 1323 return NULL; 1324 } else { 1325 assert(s->is_shared(), "must be"); 1326 } 1327 } 1328 1329 Array<Klass*>* interfaces = ik->local_interfaces(); 1330 int num_interfaces = interfaces->length(); 1331 for (int index = 0; index < num_interfaces; index++) { 1332 Klass* k = interfaces->at(index); 1333 Symbol* name = k->name(); 1334 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1335 if (k != i) { 1336 // The dynamically resolved interface class is not the same as the one we used during dump time, 1337 // so we cannot use ik. 1338 return NULL; 1339 } else { 1340 assert(i->is_shared(), "must be"); 1341 } 1342 } 1343 1344 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1345 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1346 if (new_ik != NULL) { 1347 // The class is changed by CFLH. Return the new class. The shared class is 1348 // not used. 1349 return new_ik; 1350 } 1351 1352 // Adjust methods to recover missing data. They need addresses for 1353 // interpreter entry points and their default native method address 1354 // must be reset. 1355 1356 // Updating methods must be done under a lock so multiple 1357 // threads don't update these in parallel 1358 // 1359 // Shared classes are all currently loaded by either the bootstrap or 1360 // internal parallel class loaders, so this will never cause a deadlock 1361 // on a custom class loader lock. 1362 1363 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1364 { 1365 HandleMark hm(THREAD); 1366 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1367 check_loader_lock_contention(lockObject, THREAD); 1368 ObjectLocker ol(lockObject, THREAD, true); 1369 // prohibited package check assumes all classes loaded from archive call 1370 // restore_unshareable_info which calls ik->set_package() 1371 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1372 } 1373 1374 ik->print_class_load_logging(loader_data, NULL, NULL); 1375 1376 // For boot loader, ensure that GetSystemPackage knows that a class in this 1377 // package was loaded. 1378 if (class_loader.is_null()) { 1379 int path_index = ik->shared_classpath_index(); 1380 ResourceMark rm; 1381 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1382 } 1383 1384 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1385 // Only dump the classes that can be stored into CDS archive 1386 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1387 ResourceMark rm(THREAD); 1388 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1389 classlist_file->flush(); 1390 } 1391 } 1392 1393 // notify a class loaded from shared object 1394 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1395 } 1396 1397 ik->set_has_passed_fingerprint_check(false); 1398 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1399 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1400 uint64_t cds_fp = ik->get_stored_fingerprint(); 1401 if (aot_fp != 0 && aot_fp == cds_fp) { 1402 // This class matches with a class saved in an AOT library 1403 ik->set_has_passed_fingerprint_check(true); 1404 } else { 1405 ResourceMark rm; 1406 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1407 } 1408 } 1409 return ik; 1410 } 1411 1412 void SystemDictionary::clear_invoke_method_table() { 1413 SymbolPropertyEntry* spe = NULL; 1414 for (int index = 0; index < _invoke_method_table->table_size(); index++) { 1415 SymbolPropertyEntry* p = _invoke_method_table->bucket(index); 1416 while (p != NULL) { 1417 spe = p; 1418 p = p->next(); 1419 _invoke_method_table->free_entry(spe); 1420 } 1421 } 1422 } 1423 #endif // INCLUDE_CDS 1424 1425 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1426 1427 if (class_loader.is_null()) { 1428 ResourceMark rm; 1429 PackageEntry* pkg_entry = NULL; 1430 bool search_only_bootloader_append = false; 1431 ClassLoaderData *loader_data = class_loader_data(class_loader); 1432 1433 // Find the package in the boot loader's package entry table. 1434 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1435 if (pkg_name != NULL) { 1436 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1437 } 1438 1439 // Prior to attempting to load the class, enforce the boot loader's 1440 // visibility boundaries. 1441 if (!Universe::is_module_initialized()) { 1442 // During bootstrapping, prior to module initialization, any 1443 // class attempting to be loaded must be checked against the 1444 // java.base packages in the boot loader's PackageEntryTable. 1445 // No class outside of java.base is allowed to be loaded during 1446 // this bootstrapping window. 1447 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1448 // Class is either in the unnamed package or in 1449 // a named package within the unnamed module. Either 1450 // case is outside of java.base, do not attempt to 1451 // load the class post java.base definition. If 1452 // java.base has not been defined, let the class load 1453 // and its package will be checked later by 1454 // ModuleEntryTable::verify_javabase_packages. 1455 if (ModuleEntryTable::javabase_defined()) { 1456 return NULL; 1457 } 1458 } else { 1459 // Check that the class' package is defined within java.base. 1460 ModuleEntry* mod_entry = pkg_entry->module(); 1461 Symbol* mod_entry_name = mod_entry->name(); 1462 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1463 return NULL; 1464 } 1465 } 1466 } else { 1467 // After the module system has been initialized, check if the class' 1468 // package is in a module defined to the boot loader. 1469 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1470 // Class is either in the unnamed package, in a named package 1471 // within a module not defined to the boot loader or in a 1472 // a named package within the unnamed module. In all cases, 1473 // limit visibility to search for the class only in the boot 1474 // loader's append path. 1475 search_only_bootloader_append = true; 1476 } 1477 } 1478 1479 // Prior to bootstrapping's module initialization, never load a class outside 1480 // of the boot loader's module path 1481 assert(Universe::is_module_initialized() || 1482 !search_only_bootloader_append, 1483 "Attempt to load a class outside of boot loader's module path"); 1484 1485 // Search the shared system dictionary for classes preloaded into the 1486 // shared spaces. 1487 InstanceKlass* k = NULL; 1488 { 1489 #if INCLUDE_CDS 1490 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1491 k = load_shared_class(class_name, class_loader, THREAD); 1492 #endif 1493 } 1494 1495 if (k == NULL) { 1496 // Use VM class loader 1497 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1498 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1499 } 1500 1501 // find_or_define_instance_class may return a different InstanceKlass 1502 if (k != NULL) { 1503 InstanceKlass* defined_k = 1504 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1505 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1506 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1507 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1508 loader_data->add_to_deallocate_list(k); 1509 k = defined_k; 1510 } else if (HAS_PENDING_EXCEPTION) { 1511 loader_data->add_to_deallocate_list(k); 1512 return NULL; 1513 } 1514 } 1515 return k; 1516 } else { 1517 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1518 ResourceMark rm(THREAD); 1519 1520 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1521 JavaThread* jt = (JavaThread*) THREAD; 1522 1523 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1524 ClassLoader::perf_app_classload_selftime(), 1525 ClassLoader::perf_app_classload_count(), 1526 jt->get_thread_stat()->perf_recursion_counts_addr(), 1527 jt->get_thread_stat()->perf_timers_addr(), 1528 PerfClassTraceTime::CLASS_LOAD); 1529 1530 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1531 // Translate to external class name format, i.e., convert '/' chars to '.' 1532 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1533 1534 JavaValue result(T_OBJECT); 1535 1536 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1537 1538 // Call public unsynchronized loadClass(String) directly for all class loaders. 1539 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1540 // acquire a class-name based lock rather than the class loader object lock. 1541 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1542 JavaCalls::call_virtual(&result, 1543 class_loader, 1544 spec_klass, 1545 vmSymbols::loadClass_name(), 1546 vmSymbols::string_class_signature(), 1547 string, 1548 CHECK_NULL); 1549 1550 assert(result.get_type() == T_OBJECT, "just checking"); 1551 oop obj = (oop) result.get_jobject(); 1552 1553 // Primitive classes return null since forName() can not be 1554 // used to obtain any of the Class objects representing primitives or void 1555 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1556 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1557 // For user defined Java class loaders, check that the name returned is 1558 // the same as that requested. This check is done for the bootstrap 1559 // loader when parsing the class file. 1560 if (class_name == k->name()) { 1561 return k; 1562 } 1563 } 1564 // Class is not found or has the wrong name, return NULL 1565 return NULL; 1566 } 1567 } 1568 1569 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1570 1571 HandleMark hm(THREAD); 1572 ClassLoaderData* loader_data = k->class_loader_data(); 1573 Handle class_loader_h(THREAD, loader_data->class_loader()); 1574 1575 // for bootstrap and other parallel classloaders don't acquire lock, 1576 // use placeholder token 1577 // If a parallelCapable class loader calls define_instance_class instead of 1578 // find_or_define_instance_class to get here, we have a timing 1579 // hole with systemDictionary updates and check_constraints 1580 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1581 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1582 compute_loader_lock_object(class_loader_h, THREAD)), 1583 "define called without lock"); 1584 } 1585 1586 // Check class-loading constraints. Throw exception if violation is detected. 1587 // Grabs and releases SystemDictionary_lock 1588 // The check_constraints/find_class call and update_dictionary sequence 1589 // must be "atomic" for a specific class/classloader pair so we never 1590 // define two different instanceKlasses for that class/classloader pair. 1591 // Existing classloaders will call define_instance_class with the 1592 // classloader lock held 1593 // Parallel classloaders will call find_or_define_instance_class 1594 // which will require a token to perform the define class 1595 Symbol* name_h = k->name(); 1596 Dictionary* dictionary = loader_data->dictionary(); 1597 unsigned int d_hash = dictionary->compute_hash(name_h); 1598 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1599 1600 // Register class just loaded with class loader (placed in Vector) 1601 // Note we do this before updating the dictionary, as this can 1602 // fail with an OutOfMemoryError (if it does, we will *not* put this 1603 // class in the dictionary and will not update the class hierarchy). 1604 // JVMTI FollowReferences needs to find the classes this way. 1605 if (k->class_loader() != NULL) { 1606 methodHandle m(THREAD, Universe::loader_addClass_method()); 1607 JavaValue result(T_VOID); 1608 JavaCallArguments args(class_loader_h); 1609 args.push_oop(Handle(THREAD, k->java_mirror())); 1610 JavaCalls::call(&result, m, &args, CHECK); 1611 } 1612 1613 // Add the new class. We need recompile lock during update of CHA. 1614 { 1615 unsigned int p_hash = placeholders()->compute_hash(name_h); 1616 int p_index = placeholders()->hash_to_index(p_hash); 1617 1618 MutexLocker mu_r(Compile_lock, THREAD); 1619 1620 // Add to class hierarchy, initialize vtables, and do possible 1621 // deoptimizations. 1622 add_to_hierarchy(k, CHECK); // No exception, but can block 1623 1624 // Add to systemDictionary - so other classes can see it. 1625 // Grabs and releases SystemDictionary_lock 1626 update_dictionary(d_hash, p_index, p_hash, 1627 k, class_loader_h, THREAD); 1628 } 1629 k->eager_initialize(THREAD); 1630 1631 // notify jvmti 1632 if (JvmtiExport::should_post_class_load()) { 1633 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1634 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1635 1636 } 1637 class_define_event(k, loader_data); 1638 } 1639 1640 // Support parallel classloading 1641 // All parallel class loaders, including bootstrap classloader 1642 // lock a placeholder entry for this class/class_loader pair 1643 // to allow parallel defines of different classes for this class loader 1644 // With AllowParallelDefine flag==true, in case they do not synchronize around 1645 // FindLoadedClass/DefineClass, calls, we check for parallel 1646 // loading for them, wait if a defineClass is in progress 1647 // and return the initial requestor's results 1648 // This flag does not apply to the bootstrap classloader. 1649 // With AllowParallelDefine flag==false, call through to define_instance_class 1650 // which will throw LinkageError: duplicate class definition. 1651 // False is the requested default. 1652 // For better performance, the class loaders should synchronize 1653 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1654 // potentially waste time reading and parsing the bytestream. 1655 // Note: VM callers should ensure consistency of k/class_name,class_loader 1656 // Be careful when modifying this code: once you have run 1657 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1658 // you need to find_and_remove it before returning. 1659 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1660 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1661 InstanceKlass* k, TRAPS) { 1662 1663 Symbol* name_h = k->name(); // passed in class_name may be null 1664 ClassLoaderData* loader_data = class_loader_data(class_loader); 1665 Dictionary* dictionary = loader_data->dictionary(); 1666 1667 unsigned int d_hash = dictionary->compute_hash(name_h); 1668 1669 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1670 unsigned int p_hash = placeholders()->compute_hash(name_h); 1671 int p_index = placeholders()->hash_to_index(p_hash); 1672 PlaceholderEntry* probe; 1673 1674 { 1675 MutexLocker mu(SystemDictionary_lock, THREAD); 1676 // First check if class already defined 1677 if (is_parallelDefine(class_loader)) { 1678 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1679 if (check != NULL) { 1680 return check; 1681 } 1682 } 1683 1684 // Acquire define token for this class/classloader 1685 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1686 // Wait if another thread defining in parallel 1687 // All threads wait - even those that will throw duplicate class: otherwise 1688 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1689 // if other thread has not finished updating dictionary 1690 while (probe->definer() != NULL) { 1691 SystemDictionary_lock->wait(); 1692 } 1693 // Only special cases allow parallel defines and can use other thread's results 1694 // Other cases fall through, and may run into duplicate defines 1695 // caught by finding an entry in the SystemDictionary 1696 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1697 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1698 SystemDictionary_lock->notify_all(); 1699 #ifdef ASSERT 1700 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1701 assert(check != NULL, "definer missed recording success"); 1702 #endif 1703 return probe->instance_klass(); 1704 } else { 1705 // This thread will define the class (even if earlier thread tried and had an error) 1706 probe->set_definer(THREAD); 1707 } 1708 } 1709 1710 define_instance_class(k, THREAD); 1711 1712 Handle linkage_exception = Handle(); // null handle 1713 1714 // definer must notify any waiting threads 1715 { 1716 MutexLocker mu(SystemDictionary_lock, THREAD); 1717 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1718 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1719 if (probe != NULL) { 1720 if (HAS_PENDING_EXCEPTION) { 1721 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1722 CLEAR_PENDING_EXCEPTION; 1723 } else { 1724 probe->set_instance_klass(k); 1725 } 1726 probe->set_definer(NULL); 1727 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1728 SystemDictionary_lock->notify_all(); 1729 } 1730 } 1731 1732 // Can't throw exception while holding lock due to rank ordering 1733 if (linkage_exception() != NULL) { 1734 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1735 } 1736 1737 return k; 1738 } 1739 1740 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1741 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1742 if (class_loader.is_null()) { 1743 return Handle(THREAD, _system_loader_lock_obj); 1744 } else { 1745 return class_loader; 1746 } 1747 } 1748 1749 // This method is added to check how often we have to wait to grab loader 1750 // lock. The results are being recorded in the performance counters defined in 1751 // ClassLoader::_sync_systemLoaderLockContentionRate and 1752 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1753 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1754 if (!UsePerfData) { 1755 return; 1756 } 1757 1758 assert(!loader_lock.is_null(), "NULL lock object"); 1759 1760 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1761 == ObjectSynchronizer::owner_other) { 1762 // contention will likely happen, so increment the corresponding 1763 // contention counter. 1764 if (loader_lock() == _system_loader_lock_obj) { 1765 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1766 } else { 1767 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1768 } 1769 } 1770 } 1771 1772 // ---------------------------------------------------------------------------- 1773 // Lookup 1774 1775 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1776 Symbol* class_name, 1777 Dictionary* dictionary) { 1778 assert_locked_or_safepoint(SystemDictionary_lock); 1779 int index = dictionary->hash_to_index(hash); 1780 return dictionary->find_class(index, hash, class_name); 1781 } 1782 1783 1784 // Basic find on classes in the midst of being loaded 1785 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1786 ClassLoaderData* loader_data) { 1787 assert_locked_or_safepoint(SystemDictionary_lock); 1788 unsigned int p_hash = placeholders()->compute_hash(class_name); 1789 int p_index = placeholders()->hash_to_index(p_hash); 1790 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1791 } 1792 1793 1794 // Used for assertions and verification only 1795 // Precalculating the hash and index is an optimization because there are many lookups 1796 // before adding the class. 1797 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1798 assert_locked_or_safepoint(SystemDictionary_lock); 1799 #ifndef ASSERT 1800 guarantee(VerifyBeforeGC || 1801 VerifyDuringGC || 1802 VerifyBeforeExit || 1803 VerifyDuringStartup || 1804 VerifyAfterGC, "too expensive"); 1805 #endif 1806 1807 Dictionary* dictionary = loader_data->dictionary(); 1808 unsigned int d_hash = dictionary->compute_hash(class_name); 1809 return find_class(d_hash, class_name, dictionary); 1810 } 1811 1812 1813 // ---------------------------------------------------------------------------- 1814 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1815 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1816 // before a new class is used. 1817 1818 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1819 assert(k != NULL, "just checking"); 1820 assert_locked_or_safepoint(Compile_lock); 1821 1822 // Link into hierachy. Make sure the vtables are initialized before linking into 1823 k->append_to_sibling_list(); // add to superklass/sibling list 1824 k->process_interfaces(THREAD); // handle all "implements" declarations 1825 k->set_init_state(InstanceKlass::loaded); 1826 // Now flush all code that depended on old class hierarchy. 1827 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1828 // Also, first reinitialize vtable because it may have gotten out of synch 1829 // while the new class wasn't connected to the class hierarchy. 1830 CodeCache::flush_dependents_on(k); 1831 } 1832 1833 // ---------------------------------------------------------------------------- 1834 // GC support 1835 1836 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1837 roots_oops_do(blk, NULL); 1838 } 1839 1840 1841 #ifdef ASSERT 1842 class VerifySDReachableAndLiveClosure : public OopClosure { 1843 private: 1844 BoolObjectClosure* _is_alive; 1845 1846 template <class T> void do_oop_work(T* p) { 1847 oop obj = oopDesc::load_decode_heap_oop(p); 1848 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live"); 1849 } 1850 1851 public: 1852 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1853 1854 virtual void do_oop(oop* p) { do_oop_work(p); } 1855 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1856 }; 1857 #endif 1858 1859 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1860 // Note: anonymous classes are not in the SD. 1861 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, 1862 GCTimer* gc_timer, 1863 bool do_cleaning) { 1864 1865 1866 bool unloading_occurred; 1867 { 1868 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1869 1870 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1871 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, 1872 do_cleaning); 1873 } 1874 1875 if (unloading_occurred) { 1876 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1877 constraints()->purge_loader_constraints(); 1878 resolution_errors()->purge_resolution_errors(); 1879 } 1880 1881 { 1882 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1883 // Oops referenced by the protection domain cache table may get unreachable independently 1884 // of the class loader (eg. cached protection domain oops). So we need to 1885 // explicitly unlink them here. 1886 _pd_cache_table->unlink(is_alive); 1887 1888 #ifdef ASSERT 1889 VerifySDReachableAndLiveClosure cl(is_alive); 1890 _pd_cache_table->oops_do(&cl); 1891 #endif 1892 } 1893 1894 if (do_cleaning) { 1895 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1896 ResolvedMethodTable::unlink(is_alive); 1897 } 1898 1899 return unloading_occurred; 1900 } 1901 1902 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1903 strong->do_oop(&_java_system_loader); 1904 strong->do_oop(&_java_platform_loader); 1905 strong->do_oop(&_system_loader_lock_obj); 1906 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) 1907 1908 // Do strong roots marking if the closures are the same. 1909 if (strong == weak || !ClassUnloading) { 1910 // Only the protection domain oops contain references into the heap. Iterate 1911 // over all of them. 1912 _pd_cache_table->oops_do(strong); 1913 } else { 1914 if (weak != NULL) { 1915 _pd_cache_table->oops_do(weak); 1916 } 1917 } 1918 1919 // Visit extra methods 1920 invoke_method_table()->oops_do(strong); 1921 1922 if (weak != NULL) { 1923 ResolvedMethodTable::oops_do(weak); 1924 } 1925 } 1926 1927 void SystemDictionary::oops_do(OopClosure* f) { 1928 f->do_oop(&_java_system_loader); 1929 f->do_oop(&_java_platform_loader); 1930 f->do_oop(&_system_loader_lock_obj); 1931 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1932 1933 // Only the protection domain oops contain references into the heap. Iterate 1934 // over all of them. 1935 _pd_cache_table->oops_do(f); 1936 1937 // Visit extra methods 1938 invoke_method_table()->oops_do(f); 1939 1940 ResolvedMethodTable::oops_do(f); 1941 } 1942 1943 // CDS: scan and relocate all classes in the system dictionary. 1944 void SystemDictionary::classes_do(MetaspaceClosure* it) { 1945 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); 1946 } 1947 1948 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1949 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1950 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1951 it->push(well_known_klass_addr((WKID)id)); 1952 } 1953 } 1954 1955 void SystemDictionary::methods_do(void f(Method*)) { 1956 // Walk methods in loaded classes 1957 ClassLoaderDataGraph::methods_do(f); 1958 // Walk method handle intrinsics 1959 invoke_method_table()->methods_do(f); 1960 } 1961 1962 class RemoveClassesClosure : public CLDClosure { 1963 public: 1964 void do_cld(ClassLoaderData* cld) { 1965 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 1966 cld->dictionary()->remove_classes_in_error_state(); 1967 } 1968 } 1969 }; 1970 1971 void SystemDictionary::remove_classes_in_error_state() { 1972 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 1973 RemoveClassesClosure rcc; 1974 ClassLoaderDataGraph::cld_do(&rcc); 1975 } 1976 1977 // ---------------------------------------------------------------------------- 1978 // Lazily load klasses 1979 1980 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1981 // if multiple threads calling this function, only one thread will load 1982 // the class. The other threads will find the loaded version once the 1983 // class is loaded. 1984 Klass* aos = _abstract_ownable_synchronizer_klass; 1985 if (aos == NULL) { 1986 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1987 // Force a fence to prevent any read before the write completes 1988 OrderAccess::fence(); 1989 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); 1990 } 1991 } 1992 1993 // ---------------------------------------------------------------------------- 1994 // Initialization 1995 1996 void SystemDictionary::initialize(TRAPS) { 1997 // Allocate arrays 1998 _placeholders = new PlaceholderTable(_placeholder_table_size); 1999 _number_of_modifications = 0; 2000 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 2001 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 2002 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 2003 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 2004 2005 // Allocate private object used as system class loader lock 2006 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 2007 // Initialize basic classes 2008 initialize_preloaded_classes(CHECK); 2009 } 2010 2011 // Compact table of directions on the initialization of klasses: 2012 static const short wk_init_info[] = { 2013 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 2014 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 2015 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 2016 | (int)SystemDictionary::option ), 2017 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 2018 #undef WK_KLASS_INIT_INFO 2019 0 2020 }; 2021 2022 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 2023 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2024 int info = wk_init_info[id - FIRST_WKID]; 2025 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2026 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 2027 InstanceKlass** klassp = &_well_known_klasses[id]; 2028 2029 bool must_load; 2030 #if INCLUDE_JVMCI 2031 if (EnableJVMCI) { 2032 // If JVMCI is enabled we require its classes to be found. 2033 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 2034 } else 2035 #endif 2036 { 2037 must_load = (init_opt < SystemDictionary::Opt); 2038 } 2039 2040 if ((*klassp) == NULL) { 2041 Klass* k; 2042 if (must_load) { 2043 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 2044 } else { 2045 k = resolve_or_null(symbol, CHECK_0); // load optional klass 2046 } 2047 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 2048 } 2049 return ((*klassp) != NULL); 2050 } 2051 2052 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 2053 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 2054 for (int id = (int)start_id; id < (int)limit_id; id++) { 2055 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2056 int info = wk_init_info[id - FIRST_WKID]; 2057 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2058 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 2059 2060 initialize_wk_klass((WKID)id, opt, CHECK); 2061 } 2062 2063 // move the starting value forward to the limit: 2064 start_id = limit_id; 2065 } 2066 2067 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 2068 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 2069 2070 // Create the ModuleEntry for java.base. This call needs to be done here, 2071 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 2072 ClassLoader::classLoader_init2(CHECK); 2073 2074 // Preload commonly used klasses 2075 WKID scan = FIRST_WKID; 2076 // first do Object, then String, Class 2077 #if INCLUDE_CDS 2078 if (UseSharedSpaces) { 2079 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2080 // Initialize the constant pool for the Object_class 2081 Object_klass()->constants()->restore_unshareable_info(CHECK); 2082 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2083 } else 2084 #endif 2085 { 2086 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2087 } 2088 2089 // Calculate offsets for String and Class classes since they are loaded and 2090 // can be used after this point. 2091 java_lang_String::compute_offsets(); 2092 java_lang_Class::compute_offsets(); 2093 2094 // Fixup mirrors for classes loaded before java.lang.Class. 2095 // These calls iterate over the objects currently in the perm gen 2096 // so calling them at this point is matters (not before when there 2097 // are fewer objects and not later after there are more objects 2098 // in the perm gen. 2099 Universe::initialize_basic_type_mirrors(CHECK); 2100 Universe::fixup_mirrors(CHECK); 2101 2102 // do a bunch more: 2103 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2104 2105 // Preload ref klasses and set reference types 2106 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2107 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2108 2109 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2110 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2111 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2112 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2113 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2114 2115 // JSR 292 classes 2116 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2117 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2118 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 2119 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 2120 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); 2121 2122 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2123 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2124 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2125 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2126 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2127 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2128 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2129 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2130 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2131 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2132 2133 { // Compute whether we should use checkPackageAccess or NOT 2134 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2135 _has_checkPackageAccess = (method != NULL); 2136 } 2137 } 2138 2139 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2140 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2141 BasicType SystemDictionary::box_klass_type(Klass* k) { 2142 assert(k != NULL, ""); 2143 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2144 if (_box_klasses[i] == k) 2145 return (BasicType)i; 2146 } 2147 return T_OBJECT; 2148 } 2149 2150 // Constraints on class loaders. The details of the algorithm can be 2151 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2152 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2153 // that the dictionary needs to maintain a set of contraints that 2154 // must be satisfied by all classes in the dictionary. 2155 // if defining is true, then LinkageError if already in dictionary 2156 // if initiating loader, then ok if InstanceKlass matches existing entry 2157 2158 void SystemDictionary::check_constraints(unsigned int d_hash, 2159 InstanceKlass* k, 2160 Handle class_loader, bool defining, 2161 TRAPS) { 2162 const char *linkage_error1 = NULL; 2163 const char *linkage_error2 = NULL; 2164 { 2165 Symbol* name = k->name(); 2166 ClassLoaderData *loader_data = class_loader_data(class_loader); 2167 2168 MutexLocker mu(SystemDictionary_lock, THREAD); 2169 2170 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2171 if (check != NULL) { 2172 // if different InstanceKlass - duplicate class definition, 2173 // else - ok, class loaded by a different thread in parallel, 2174 // we should only have found it if it was done loading and ok to use 2175 // dictionary only holds instance classes, placeholders 2176 // also holds array classes 2177 2178 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2179 if ((defining == true) || (k != check)) { 2180 linkage_error1 = "loader (instance of "; 2181 linkage_error2 = "): attempted duplicate class definition for name: \""; 2182 } else { 2183 return; 2184 } 2185 } 2186 2187 #ifdef ASSERT 2188 Symbol* ph_check = find_placeholder(name, loader_data); 2189 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2190 #endif 2191 2192 if (linkage_error1 == NULL) { 2193 if (constraints()->check_or_update(k, class_loader, name) == false) { 2194 linkage_error1 = "loader constraint violation: loader (instance of "; 2195 linkage_error2 = ") previously initiated loading for a different type with name \""; 2196 } 2197 } 2198 } 2199 2200 // Throw error now if needed (cannot throw while holding 2201 // SystemDictionary_lock because of rank ordering) 2202 2203 if (linkage_error1) { 2204 ResourceMark rm(THREAD); 2205 const char* class_loader_name = loader_name(class_loader()); 2206 char* type_name = k->name()->as_C_string(); 2207 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) + 2208 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte. 2209 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2210 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name); 2211 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2212 } 2213 } 2214 2215 2216 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2217 // have been called. 2218 void SystemDictionary::update_dictionary(unsigned int d_hash, 2219 int p_index, unsigned int p_hash, 2220 InstanceKlass* k, 2221 Handle class_loader, 2222 TRAPS) { 2223 // Compile_lock prevents systemDictionary updates during compilations 2224 assert_locked_or_safepoint(Compile_lock); 2225 Symbol* name = k->name(); 2226 ClassLoaderData *loader_data = class_loader_data(class_loader); 2227 2228 { 2229 MutexLocker mu1(SystemDictionary_lock, THREAD); 2230 2231 // See whether biased locking is enabled and if so set it for this 2232 // klass. 2233 // Note that this must be done past the last potential blocking 2234 // point / safepoint. We enable biased locking lazily using a 2235 // VM_Operation to iterate the SystemDictionary and installing the 2236 // biasable mark word into each InstanceKlass's prototype header. 2237 // To avoid race conditions where we accidentally miss enabling the 2238 // optimization for one class in the process of being added to the 2239 // dictionary, we must not safepoint after the test of 2240 // BiasedLocking::enabled(). 2241 if (UseBiasedLocking && BiasedLocking::enabled()) { 2242 // Set biased locking bit for all loaded classes; it will be 2243 // cleared if revocation occurs too often for this type 2244 // NOTE that we must only do this when the class is initally 2245 // defined, not each time it is referenced from a new class loader 2246 if (k->class_loader() == class_loader()) { 2247 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2248 } 2249 } 2250 2251 // Make a new dictionary entry. 2252 Dictionary* dictionary = loader_data->dictionary(); 2253 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2254 if (sd_check == NULL) { 2255 dictionary->add_klass(d_hash, name, k); 2256 notice_modification(); 2257 } 2258 #ifdef ASSERT 2259 sd_check = find_class(d_hash, name, dictionary); 2260 assert (sd_check != NULL, "should have entry in dictionary"); 2261 // Note: there may be a placeholder entry: for circularity testing 2262 // or for parallel defines 2263 #endif 2264 SystemDictionary_lock->notify_all(); 2265 } 2266 } 2267 2268 2269 // Try to find a class name using the loader constraints. The 2270 // loader constraints might know about a class that isn't fully loaded 2271 // yet and these will be ignored. 2272 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2273 Symbol* class_name, Handle class_loader, TRAPS) { 2274 2275 // First see if it has been loaded directly. 2276 // Force the protection domain to be null. (This removes protection checks.) 2277 Handle no_protection_domain; 2278 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2279 no_protection_domain, CHECK_NULL); 2280 if (klass != NULL) 2281 return klass; 2282 2283 // Now look to see if it has been loaded elsewhere, and is subject to 2284 // a loader constraint that would require this loader to return the 2285 // klass that is already loaded. 2286 if (FieldType::is_array(class_name)) { 2287 // For array classes, their Klass*s are not kept in the 2288 // constraint table. The element Klass*s are. 2289 FieldArrayInfo fd; 2290 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2291 if (t != T_OBJECT) { 2292 klass = Universe::typeArrayKlassObj(t); 2293 } else { 2294 MutexLocker mu(SystemDictionary_lock, THREAD); 2295 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2296 } 2297 // If element class already loaded, allocate array klass 2298 if (klass != NULL) { 2299 klass = klass->array_klass_or_null(fd.dimension()); 2300 } 2301 } else { 2302 MutexLocker mu(SystemDictionary_lock, THREAD); 2303 // Non-array classes are easy: simply check the constraint table. 2304 klass = constraints()->find_constrained_klass(class_name, class_loader); 2305 } 2306 2307 return klass; 2308 } 2309 2310 2311 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2312 Handle class_loader1, 2313 Handle class_loader2, 2314 Thread* THREAD) { 2315 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2316 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2317 2318 Symbol* constraint_name = NULL; 2319 if (!FieldType::is_array(class_name)) { 2320 constraint_name = class_name; 2321 } else { 2322 // For array classes, their Klass*s are not kept in the 2323 // constraint table. The element classes are. 2324 FieldArrayInfo fd; 2325 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2326 // primitive types always pass 2327 if (t != T_OBJECT) { 2328 return true; 2329 } else { 2330 constraint_name = fd.object_key(); 2331 } 2332 } 2333 2334 Dictionary* dictionary1 = loader_data1->dictionary(); 2335 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2336 2337 Dictionary* dictionary2 = loader_data2->dictionary(); 2338 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2339 2340 { 2341 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2342 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2343 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2344 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2345 klass2, class_loader2); 2346 } 2347 } 2348 2349 // Add entry to resolution error table to record the error when the first 2350 // attempt to resolve a reference to a class has failed. 2351 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2352 Symbol* error, Symbol* message) { 2353 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2354 int index = resolution_errors()->hash_to_index(hash); 2355 { 2356 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2357 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2358 } 2359 } 2360 2361 // Delete a resolution error for RedefineClasses for a constant pool is going away 2362 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2363 resolution_errors()->delete_entry(pool); 2364 } 2365 2366 // Lookup resolution error table. Returns error if found, otherwise NULL. 2367 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2368 Symbol** message) { 2369 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2370 int index = resolution_errors()->hash_to_index(hash); 2371 { 2372 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2373 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2374 if (entry != NULL) { 2375 *message = entry->message(); 2376 return entry->error(); 2377 } else { 2378 return NULL; 2379 } 2380 } 2381 } 2382 2383 2384 // Signature constraints ensure that callers and callees agree about 2385 // the meaning of type names in their signatures. This routine is the 2386 // intake for constraints. It collects them from several places: 2387 // 2388 // * LinkResolver::resolve_method (if check_access is true) requires 2389 // that the resolving class (the caller) and the defining class of 2390 // the resolved method (the callee) agree on each type in the 2391 // method's signature. 2392 // 2393 // * LinkResolver::resolve_interface_method performs exactly the same 2394 // checks. 2395 // 2396 // * LinkResolver::resolve_field requires that the constant pool 2397 // attempting to link to a field agree with the field's defining 2398 // class about the type of the field signature. 2399 // 2400 // * klassVtable::initialize_vtable requires that, when a class 2401 // overrides a vtable entry allocated by a superclass, that the 2402 // overriding method (i.e., the callee) agree with the superclass 2403 // on each type in the method's signature. 2404 // 2405 // * klassItable::initialize_itable requires that, when a class fills 2406 // in its itables, for each non-abstract method installed in an 2407 // itable, the method (i.e., the callee) agree with the interface 2408 // on each type in the method's signature. 2409 // 2410 // All those methods have a boolean (check_access, checkconstraints) 2411 // which turns off the checks. This is used from specialized contexts 2412 // such as bootstrapping, dumping, and debugging. 2413 // 2414 // No direct constraint is placed between the class and its 2415 // supertypes. Constraints are only placed along linked relations 2416 // between callers and callees. When a method overrides or implements 2417 // an abstract method in a supertype (superclass or interface), the 2418 // constraints are placed as if the supertype were the caller to the 2419 // overriding method. (This works well, since callers to the 2420 // supertype have already established agreement between themselves and 2421 // the supertype.) As a result of all this, a class can disagree with 2422 // its supertype about the meaning of a type name, as long as that 2423 // class neither calls a relevant method of the supertype, nor is 2424 // called (perhaps via an override) from the supertype. 2425 // 2426 // 2427 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2428 // 2429 // Make sure all class components (including arrays) in the given 2430 // signature will be resolved to the same class in both loaders. 2431 // Returns the name of the type that failed a loader constraint check, or 2432 // NULL if no constraint failed. No exception except OOME is thrown. 2433 // Arrays are not added to the loader constraint table, their elements are. 2434 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2435 Handle loader1, Handle loader2, 2436 bool is_method, TRAPS) { 2437 // Nothing to do if loaders are the same. 2438 if (loader1() == loader2()) { 2439 return NULL; 2440 } 2441 2442 SignatureStream sig_strm(signature, is_method); 2443 while (!sig_strm.is_done()) { 2444 if (sig_strm.is_object()) { 2445 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2446 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2447 return sig; 2448 } 2449 } 2450 sig_strm.next(); 2451 } 2452 return NULL; 2453 } 2454 2455 2456 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2457 Symbol* signature, 2458 TRAPS) { 2459 methodHandle empty; 2460 assert(MethodHandles::is_signature_polymorphic(iid) && 2461 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2462 iid != vmIntrinsics::_invokeGeneric, 2463 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2464 2465 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2466 int index = invoke_method_table()->hash_to_index(hash); 2467 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2468 methodHandle m; 2469 if (spe == NULL || spe->method() == NULL) { 2470 spe = NULL; 2471 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2472 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2473 if (!Arguments::is_interpreter_only()) { 2474 // Generate a compiled form of the MH intrinsic. 2475 AdapterHandlerLibrary::create_native_wrapper(m); 2476 // Check if have the compiled code. 2477 if (!m->has_compiled_code()) { 2478 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2479 "Out of space in CodeCache for method handle intrinsic", empty); 2480 } 2481 } 2482 // Now grab the lock. We might have to throw away the new method, 2483 // if a racing thread has managed to install one at the same time. 2484 { 2485 MutexLocker ml(SystemDictionary_lock, THREAD); 2486 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2487 if (spe == NULL) 2488 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2489 if (spe->method() == NULL) 2490 spe->set_method(m()); 2491 } 2492 } 2493 2494 assert(spe != NULL && spe->method() != NULL, ""); 2495 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2496 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2497 "MH intrinsic invariant"); 2498 return spe->method(); 2499 } 2500 2501 // Helper for unpacking the return value from linkMethod and linkCallSite. 2502 static methodHandle unpack_method_and_appendix(Handle mname, 2503 Klass* accessing_klass, 2504 objArrayHandle appendix_box, 2505 Handle* appendix_result, 2506 TRAPS) { 2507 methodHandle empty; 2508 if (mname.not_null()) { 2509 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2510 if (m != NULL) { 2511 oop appendix = appendix_box->obj_at(0); 2512 if (TraceMethodHandles) { 2513 #ifndef PRODUCT 2514 ttyLocker ttyl; 2515 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2516 m->print(); 2517 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2518 tty->cr(); 2519 #endif //PRODUCT 2520 } 2521 (*appendix_result) = Handle(THREAD, appendix); 2522 // the target is stored in the cpCache and if a reference to this 2523 // MethodName is dropped we need a way to make sure the 2524 // class_loader containing this method is kept alive. 2525 // FIXME: the appendix might also preserve this dependency. 2526 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2527 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2528 return methodHandle(THREAD, m); 2529 } 2530 } 2531 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2532 return empty; 2533 } 2534 2535 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2536 Symbol* name, 2537 Symbol* signature, 2538 Klass* accessing_klass, 2539 Handle *appendix_result, 2540 Handle *method_type_result, 2541 TRAPS) { 2542 methodHandle empty; 2543 assert(THREAD->can_call_java() ,""); 2544 Handle method_type = 2545 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2546 2547 int ref_kind = JVM_REF_invokeVirtual; 2548 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2549 Handle name_str (THREAD, name_oop); 2550 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2551 assert(appendix_box->obj_at(0) == NULL, ""); 2552 2553 // This should not happen. JDK code should take care of that. 2554 if (accessing_klass == NULL || method_type.is_null()) { 2555 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2556 } 2557 2558 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2559 JavaCallArguments args; 2560 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2561 args.push_int(ref_kind); 2562 args.push_oop(Handle(THREAD, klass->java_mirror())); 2563 args.push_oop(name_str); 2564 args.push_oop(method_type); 2565 args.push_oop(appendix_box); 2566 JavaValue result(T_OBJECT); 2567 JavaCalls::call_static(&result, 2568 SystemDictionary::MethodHandleNatives_klass(), 2569 vmSymbols::linkMethod_name(), 2570 vmSymbols::linkMethod_signature(), 2571 &args, CHECK_(empty)); 2572 Handle mname(THREAD, (oop) result.get_jobject()); 2573 (*method_type_result) = method_type; 2574 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2575 } 2576 2577 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2578 // We must ensure that all class loaders everywhere will reach this class, for any client. 2579 // This is a safe bet for public classes in java.lang, such as Object and String. 2580 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2581 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2582 static bool is_always_visible_class(oop mirror) { 2583 Klass* klass = java_lang_Class::as_Klass(mirror); 2584 if (klass->is_objArray_klass()) { 2585 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2586 } 2587 if (klass->is_typeArray_klass()) { 2588 return true; // primitive array 2589 } 2590 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2591 return klass->is_public() && 2592 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2593 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2594 } 2595 2596 2597 // Return the Java mirror (java.lang.Class instance) for a single-character 2598 // descriptor. This result, when available, is the same as produced by the 2599 // heavier API point of the same name that takes a Symbol. 2600 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2601 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2602 } 2603 2604 // Find or construct the Java mirror (java.lang.Class instance) for a 2605 // for the given field type signature, as interpreted relative to the 2606 // given class loader. Handles primitives, void, references, arrays, 2607 // and all other reflectable types, except method types. 2608 // N.B. Code in reflection should use this entry point. 2609 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2610 Klass* accessing_klass, 2611 Handle class_loader, 2612 Handle protection_domain, 2613 SignatureStream::FailureMode failure_mode, 2614 TRAPS) { 2615 Handle empty; 2616 2617 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2618 "one or the other, or perhaps neither"); 2619 2620 Symbol* type = signature; 2621 2622 // What we have here must be a valid field descriptor, 2623 // and all valid field descriptors are supported. 2624 // Produce the same java.lang.Class that reflection reports. 2625 if (type->utf8_length() == 1) { 2626 2627 // It's a primitive. (Void has a primitive mirror too.) 2628 char ch = (char) type->byte_at(0); 2629 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2630 return Handle(THREAD, find_java_mirror_for_type(ch)); 2631 2632 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2633 2634 // It's a reference type. 2635 if (accessing_klass != NULL) { 2636 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2637 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2638 } 2639 Klass* constant_type_klass; 2640 if (failure_mode == SignatureStream::ReturnNull) { 2641 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2642 CHECK_(empty)); 2643 } else { 2644 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2645 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2646 throw_error, CHECK_(empty)); 2647 } 2648 if (constant_type_klass == NULL) { 2649 return Handle(); // report failure this way 2650 } 2651 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2652 2653 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2654 if (accessing_klass != NULL) { 2655 Klass* sel_klass = constant_type_klass; 2656 bool fold_type_to_class = true; 2657 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2658 fold_type_to_class, CHECK_(empty)); 2659 } 2660 2661 return mirror; 2662 2663 } 2664 2665 // Fall through to an error. 2666 assert(false, "unsupported mirror syntax"); 2667 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2668 } 2669 2670 2671 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2672 // signature, as interpreted relative to the given class loader. 2673 // Because of class loader constraints, all method handle usage must be 2674 // consistent with this loader. 2675 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2676 Klass* accessing_klass, 2677 TRAPS) { 2678 Handle empty; 2679 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2680 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2681 int index = invoke_method_table()->hash_to_index(hash); 2682 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2683 if (spe != NULL && spe->method_type() != NULL) { 2684 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2685 return Handle(THREAD, spe->method_type()); 2686 } else if (!THREAD->can_call_java()) { 2687 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2688 return Handle(); // do not attempt from within compiler, unless it was cached 2689 } 2690 2691 Handle class_loader, protection_domain; 2692 if (accessing_klass != NULL) { 2693 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2694 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2695 } 2696 bool can_be_cached = true; 2697 int npts = ArgumentCount(signature).size(); 2698 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2699 int arg = 0; 2700 Handle rt; // the return type from the signature 2701 ResourceMark rm(THREAD); 2702 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2703 oop mirror = NULL; 2704 if (can_be_cached) { 2705 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2706 mirror = ss.as_java_mirror(Handle(), Handle(), 2707 SignatureStream::ReturnNull, CHECK_(empty)); 2708 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2709 // Fall back to accessing_klass context. 2710 can_be_cached = false; 2711 } 2712 } 2713 if (!can_be_cached) { 2714 // Resolve, throwing a real error if it doesn't work. 2715 mirror = ss.as_java_mirror(class_loader, protection_domain, 2716 SignatureStream::NCDFError, CHECK_(empty)); 2717 } 2718 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string()); 2719 if (ss.at_return_type()) 2720 rt = Handle(THREAD, mirror); 2721 else 2722 pts->obj_at_put(arg++, mirror); 2723 2724 // Check accessibility. 2725 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2726 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2727 mirror = NULL; // safety 2728 // Emulate ConstantPool::verify_constant_pool_resolve. 2729 bool fold_type_to_class = true; 2730 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2731 fold_type_to_class, CHECK_(empty)); 2732 } 2733 } 2734 assert(arg == npts, ""); 2735 2736 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2737 JavaCallArguments args(Handle(THREAD, rt())); 2738 args.push_oop(pts); 2739 JavaValue result(T_OBJECT); 2740 JavaCalls::call_static(&result, 2741 SystemDictionary::MethodHandleNatives_klass(), 2742 vmSymbols::findMethodHandleType_name(), 2743 vmSymbols::findMethodHandleType_signature(), 2744 &args, CHECK_(empty)); 2745 Handle method_type(THREAD, (oop) result.get_jobject()); 2746 2747 if (can_be_cached) { 2748 // We can cache this MethodType inside the JVM. 2749 MutexLocker ml(SystemDictionary_lock, THREAD); 2750 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2751 if (spe == NULL) 2752 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2753 if (spe->method_type() == NULL) { 2754 spe->set_method_type(method_type()); 2755 } 2756 } 2757 2758 // report back to the caller with the MethodType 2759 return method_type; 2760 } 2761 2762 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2763 Klass* accessing_klass, 2764 TRAPS) { 2765 Handle empty; 2766 ResourceMark rm(THREAD); 2767 SignatureStream ss(signature, /*is_method=*/ false); 2768 if (!ss.is_done()) { 2769 Handle class_loader, protection_domain; 2770 if (accessing_klass != NULL) { 2771 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2772 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2773 } 2774 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2775 ss.next(); 2776 if (ss.is_done()) { 2777 return Handle(THREAD, mirror); 2778 } 2779 } 2780 return empty; 2781 } 2782 2783 // Ask Java code to find or construct a method handle constant. 2784 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2785 int ref_kind, //e.g., JVM_REF_invokeVirtual 2786 Klass* callee, 2787 Symbol* name, 2788 Symbol* signature, 2789 TRAPS) { 2790 Handle empty; 2791 if (caller == NULL) { 2792 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2793 } 2794 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2795 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2796 2797 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2798 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2799 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2800 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2801 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2802 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2803 2804 if (ref_kind == JVM_REF_invokeVirtual && 2805 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() && 2806 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) { 2807 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact(). 2808 // They are public signature polymorphic methods, but require appendix argument 2809 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them 2810 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2811 } else { 2812 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty)); 2813 } 2814 2815 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2816 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2817 2818 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2819 JavaCallArguments args; 2820 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2821 args.push_int(ref_kind); 2822 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2823 args.push_oop(name_str); 2824 args.push_oop(type); 2825 JavaValue result(T_OBJECT); 2826 JavaCalls::call_static(&result, 2827 SystemDictionary::MethodHandleNatives_klass(), 2828 vmSymbols::linkMethodHandleConstant_name(), 2829 vmSymbols::linkMethodHandleConstant_signature(), 2830 &args, CHECK_(empty)); 2831 return Handle(THREAD, (oop) result.get_jobject()); 2832 } 2833 2834 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry 2835 Handle SystemDictionary::link_dynamic_constant(Klass* caller, 2836 int condy_index, 2837 Handle bootstrap_specifier, 2838 Symbol* name, 2839 Symbol* type, 2840 TRAPS) { 2841 Handle empty; 2842 Handle bsm, info; 2843 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2844 bsm = bootstrap_specifier; 2845 } else { 2846 assert(bootstrap_specifier->is_objArray(), ""); 2847 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2848 assert(args->length() == 2, ""); 2849 bsm = Handle(THREAD, args->obj_at(0)); 2850 info = Handle(THREAD, args->obj_at(1)); 2851 } 2852 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2853 "caller must supply a valid BSM"); 2854 2855 // This should not happen. JDK code should take care of that. 2856 if (caller == NULL) { 2857 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); 2858 } 2859 2860 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2861 2862 // Resolve the constant type in the context of the caller class 2863 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, 2864 CHECK_(empty)); 2865 2866 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) 2867 JavaCallArguments args; 2868 args.push_oop(Handle(THREAD, caller->java_mirror())); 2869 args.push_int(condy_index); 2870 args.push_oop(bsm); 2871 args.push_oop(constant_name); 2872 args.push_oop(type_mirror); 2873 args.push_oop(info); 2874 JavaValue result(T_OBJECT); 2875 JavaCalls::call_static(&result, 2876 SystemDictionary::MethodHandleNatives_klass(), 2877 vmSymbols::linkDynamicConstant_name(), 2878 vmSymbols::linkDynamicConstant_signature(), 2879 &args, CHECK_(empty)); 2880 2881 return Handle(THREAD, (oop) result.get_jobject()); 2882 } 2883 2884 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2885 // name and signature, as interpreted relative to the given class loader. 2886 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2887 int indy_index, 2888 Handle bootstrap_specifier, 2889 Symbol* name, 2890 Symbol* type, 2891 Handle *appendix_result, 2892 Handle *method_type_result, 2893 TRAPS) { 2894 methodHandle empty; 2895 Handle bsm, info; 2896 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2897 bsm = bootstrap_specifier; 2898 } else { 2899 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2900 assert(args->length() == 2, ""); 2901 bsm = Handle(THREAD, args->obj_at(0)); 2902 info = Handle(THREAD, args->obj_at(1)); 2903 } 2904 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2905 "caller must supply a valid BSM"); 2906 2907 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2908 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2909 2910 // This should not happen. JDK code should take care of that. 2911 if (caller == NULL || method_type.is_null()) { 2912 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2913 } 2914 2915 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2916 assert(appendix_box->obj_at(0) == NULL, ""); 2917 2918 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2919 JavaCallArguments args; 2920 args.push_oop(Handle(THREAD, caller->java_mirror())); 2921 args.push_int(indy_index); 2922 args.push_oop(bsm); 2923 args.push_oop(method_name); 2924 args.push_oop(method_type); 2925 args.push_oop(info); 2926 args.push_oop(appendix_box); 2927 JavaValue result(T_OBJECT); 2928 JavaCalls::call_static(&result, 2929 SystemDictionary::MethodHandleNatives_klass(), 2930 vmSymbols::linkCallSite_name(), 2931 vmSymbols::linkCallSite_signature(), 2932 &args, CHECK_(empty)); 2933 Handle mname(THREAD, (oop) result.get_jobject()); 2934 (*method_type_result) = method_type; 2935 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2936 } 2937 2938 // Protection domain cache table handling 2939 2940 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2941 return _pd_cache_table->get(protection_domain); 2942 } 2943 2944 #if INCLUDE_CDS 2945 void SystemDictionary::reorder_dictionary_for_sharing() { 2946 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); 2947 } 2948 #endif 2949 2950 size_t SystemDictionary::count_bytes_for_buckets() { 2951 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); 2952 } 2953 2954 size_t SystemDictionary::count_bytes_for_table() { 2955 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); 2956 } 2957 2958 void SystemDictionary::copy_buckets(char* top, char* end) { 2959 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2960 } 2961 2962 void SystemDictionary::copy_table(char* top, char* end) { 2963 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2964 } 2965 2966 // ---------------------------------------------------------------------------- 2967 void SystemDictionary::print_shared(outputStream *st) { 2968 shared_dictionary()->print_on(st); 2969 } 2970 2971 void SystemDictionary::print_on(outputStream *st) { 2972 if (shared_dictionary() != NULL) { 2973 st->print_cr("Shared Dictionary"); 2974 shared_dictionary()->print_on(st); 2975 st->cr(); 2976 } 2977 2978 GCMutexLocker mu(SystemDictionary_lock); 2979 2980 ClassLoaderDataGraph::print_dictionary(st); 2981 2982 // Placeholders 2983 placeholders()->print_on(st); 2984 st->cr(); 2985 2986 // loader constraints - print under SD_lock 2987 constraints()->print_on(st); 2988 st->cr(); 2989 2990 _pd_cache_table->print_on(st); 2991 st->cr(); 2992 } 2993 2994 void SystemDictionary::verify() { 2995 guarantee(constraints() != NULL, 2996 "Verify of loader constraints failed"); 2997 guarantee(placeholders()->number_of_entries() >= 0, 2998 "Verify of placeholders failed"); 2999 3000 GCMutexLocker mu(SystemDictionary_lock); 3001 3002 // Verify dictionary 3003 ClassLoaderDataGraph::verify_dictionary(); 3004 3005 placeholders()->verify(); 3006 3007 // Verify constraint table 3008 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 3009 constraints()->verify(placeholders()); 3010 3011 _pd_cache_table->verify(); 3012 } 3013 3014 void SystemDictionary::dump(outputStream *st, bool verbose) { 3015 assert_locked_or_safepoint(SystemDictionary_lock); 3016 if (verbose) { 3017 print_on(st); 3018 } else { 3019 if (shared_dictionary() != NULL) { 3020 shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); 3021 } 3022 ClassLoaderDataGraph::print_dictionary_statistics(st); 3023 placeholders()->print_table_statistics(st, "Placeholder Table"); 3024 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 3025 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 3026 } 3027 } 3028 3029 // Utility for dumping dictionaries. 3030 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 3031 DCmdWithParser(output, heap), 3032 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 3033 "BOOLEAN", false, "false") { 3034 _dcmdparser.add_dcmd_option(&_verbose); 3035 } 3036 3037 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 3038 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 3039 _verbose.value()); 3040 VMThread::execute(&dumper); 3041 } 3042 3043 int SystemDictionaryDCmd::num_arguments() { 3044 ResourceMark rm; 3045 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 3046 if (dcmd != NULL) { 3047 DCmdMark mark(dcmd); 3048 return dcmd->_dcmdparser.num_arguments(); 3049 } else { 3050 return 0; 3051 } 3052 } 3053 3054 class CombineDictionariesClosure : public CLDClosure { 3055 private: 3056 Dictionary* _master_dictionary; 3057 public: 3058 CombineDictionariesClosure(Dictionary* master_dictionary) : 3059 _master_dictionary(master_dictionary) {} 3060 void do_cld(ClassLoaderData* cld) { 3061 ResourceMark rm; 3062 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 3063 for (int i = 0; i < cld->dictionary()->table_size(); ++i) { 3064 Dictionary* curr_dictionary = cld->dictionary(); 3065 DictionaryEntry* p = curr_dictionary->bucket(i); 3066 while (p != NULL) { 3067 Symbol* name = p->instance_klass()->name(); 3068 unsigned int d_hash = _master_dictionary->compute_hash(name); 3069 int d_index = _master_dictionary->hash_to_index(d_hash); 3070 DictionaryEntry* next = p->next(); 3071 if (p->literal()->class_loader_data() != cld) { 3072 // This is an initiating class loader entry; don't use it 3073 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); 3074 curr_dictionary->free_entry(p); 3075 } else { 3076 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); 3077 curr_dictionary->unlink_entry(p); 3078 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. 3079 _master_dictionary->add_entry(d_index, p); 3080 } 3081 p = next; 3082 } 3083 *curr_dictionary->bucket_addr(i) = NULL; 3084 } 3085 } 3086 } 3087 }; 3088 3089 // Combining platform and system loader dictionaries into boot loader dictionaries. 3090 // During run time, we only have one shared dictionary. 3091 void SystemDictionary::combine_shared_dictionaries() { 3092 assert(DumpSharedSpaces, "dump time only"); 3093 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); 3094 CombineDictionariesClosure cdc(master_dictionary); 3095 ClassLoaderDataGraph::cld_do(&cdc); 3096 3097 // These tables are no longer valid or necessary. Keeping them around will 3098 // cause SystemDictionary::verify() to fail. Let's empty them. 3099 _placeholders = new PlaceholderTable(_placeholder_table_size); 3100 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 3101 3102 NOT_PRODUCT(SystemDictionary::verify()); 3103 } 3104 3105 // caller needs ResourceMark 3106 const char* SystemDictionary::loader_name(const oop loader) { 3107 return ((loader) == NULL ? "<bootloader>" : 3108 InstanceKlass::cast((loader)->klass())->name()->as_C_string()); 3109 } 3110 3111 // caller needs ResourceMark 3112 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { 3113 return (loader_data->class_loader() == NULL ? "<bootloader>" : 3114 SystemDictionary::loader_name(loader_data->class_loader())); 3115 }