1 /* 2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "aot/aotLoader.hpp" 27 #include "classfile/classFileParser.hpp" 28 #include "classfile/classFileStream.hpp" 29 #include "classfile/classLoader.hpp" 30 #include "classfile/classLoaderData.inline.hpp" 31 #include "classfile/classLoaderExt.hpp" 32 #include "classfile/dictionary.hpp" 33 #include "classfile/javaClasses.inline.hpp" 34 #include "classfile/klassFactory.hpp" 35 #include "classfile/loaderConstraints.hpp" 36 #include "classfile/packageEntry.hpp" 37 #include "classfile/placeholders.hpp" 38 #include "classfile/protectionDomainCache.hpp" 39 #include "classfile/resolutionErrors.hpp" 40 #include "classfile/stringTable.hpp" 41 #include "classfile/systemDictionary.hpp" 42 #include "classfile/vmSymbols.hpp" 43 #include "code/codeCache.hpp" 44 #include "compiler/compileBroker.hpp" 45 #include "gc/shared/gcLocker.hpp" 46 #include "gc/shared/gcTraceTime.inline.hpp" 47 #include "interpreter/bytecodeStream.hpp" 48 #include "interpreter/interpreter.hpp" 49 #include "logging/log.hpp" 50 #include "logging/logStream.hpp" 51 #include "memory/filemap.hpp" 52 #include "memory/metaspaceClosure.hpp" 53 #include "memory/oopFactory.hpp" 54 #include "memory/resourceArea.hpp" 55 #include "oops/instanceKlass.hpp" 56 #include "oops/instanceRefKlass.hpp" 57 #include "oops/klass.inline.hpp" 58 #include "oops/methodData.hpp" 59 #include "oops/objArrayKlass.hpp" 60 #include "oops/objArrayOop.inline.hpp" 61 #include "oops/oop.inline.hpp" 62 #include "oops/symbol.hpp" 63 #include "oops/typeArrayKlass.hpp" 64 #include "prims/jvm.h" 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_loadClassInternal = false; 110 bool SystemDictionary::_has_checkPackageAccess = false; 111 112 // lazily initialized klass variables 113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 114 115 // Default ProtectionDomainCacheSize value 116 117 const int defaultProtectionDomainCacheSize = 1009; 118 119 120 // ---------------------------------------------------------------------------- 121 // Java-level SystemLoader and PlatformLoader 122 123 oop SystemDictionary::java_system_loader() { 124 return _java_system_loader; 125 } 126 127 oop SystemDictionary::java_platform_loader() { 128 return _java_platform_loader; 129 } 130 131 void SystemDictionary::compute_java_loaders(TRAPS) { 132 JavaValue result(T_OBJECT); 133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); 134 JavaCalls::call_static(&result, 135 class_loader_klass, 136 vmSymbols::getSystemClassLoader_name(), 137 vmSymbols::void_classloader_signature(), 138 CHECK); 139 140 _java_system_loader = (oop)result.get_jobject(); 141 142 JavaCalls::call_static(&result, 143 class_loader_klass, 144 vmSymbols::getPlatformClassLoader_name(), 145 vmSymbols::void_classloader_signature(), 146 CHECK); 147 148 _java_platform_loader = (oop)result.get_jobject(); 149 150 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) 151 } 152 153 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 154 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 155 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD); 156 } 157 158 // ---------------------------------------------------------------------------- 159 // Parallel class loading check 160 161 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 162 if (UnsyncloadClass || class_loader.is_null()) return true; 163 if (AlwaysLockClassLoader) return false; 164 return java_lang_ClassLoader::parallelCapable(class_loader()); 165 } 166 // ---------------------------------------------------------------------------- 167 // ParallelDefineClass flag does not apply to bootclass loader 168 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 169 if (class_loader.is_null()) return false; 170 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 171 return true; 172 } 173 return false; 174 } 175 176 // Returns true if the passed class loader is the builtin application class loader 177 // or a custom system class loader. A customer system class loader can be 178 // specified via -Djava.system.class.loader. 179 bool SystemDictionary::is_system_class_loader(oop class_loader) { 180 if (class_loader == NULL) { 181 return false; 182 } 183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 184 class_loader == _java_system_loader); 185 } 186 187 // Returns true if the passed class loader is the platform class loader. 188 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 189 if (class_loader == NULL) { 190 return false; 191 } 192 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 193 } 194 195 // ---------------------------------------------------------------------------- 196 // Resolving of classes 197 198 // Forwards to resolve_or_null 199 200 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 201 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 202 if (HAS_PENDING_EXCEPTION || klass == NULL) { 203 // can return a null klass 204 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 205 } 206 return klass; 207 } 208 209 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 210 bool throw_error, 211 Klass* klass, TRAPS) { 212 if (HAS_PENDING_EXCEPTION) { 213 // If we have a pending exception we forward it to the caller, unless throw_error is true, 214 // in which case we have to check whether the pending exception is a ClassNotFoundException, 215 // and if so convert it to a NoClassDefFoundError 216 // And chain the original ClassNotFoundException 217 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 218 ResourceMark rm(THREAD); 219 assert(klass == NULL, "Should not have result with exception pending"); 220 Handle e(THREAD, PENDING_EXCEPTION); 221 CLEAR_PENDING_EXCEPTION; 222 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 223 } else { 224 return NULL; 225 } 226 } 227 // Class not found, throw appropriate error or exception depending on value of throw_error 228 if (klass == NULL) { 229 ResourceMark rm(THREAD); 230 if (throw_error) { 231 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 232 } else { 233 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 234 } 235 } 236 return klass; 237 } 238 239 240 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 241 bool throw_error, TRAPS) 242 { 243 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 244 } 245 246 247 // Forwards to resolve_instance_class_or_null 248 249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 250 assert(THREAD->can_call_java(), 251 "can not load classes with compiler thread: class=%s, classloader=%s", 252 class_name->as_C_string(), 253 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 254 if (FieldType::is_array(class_name)) { 255 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 256 } else if (FieldType::is_obj(class_name)) { 257 ResourceMark rm(THREAD); 258 // Ignore wrapping L and ;. 259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 260 class_name->utf8_length() - 2, CHECK_NULL); 261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 262 } else { 263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 264 } 265 } 266 267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 268 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 269 } 270 271 // Forwards to resolve_instance_class_or_null 272 273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 274 Handle class_loader, 275 Handle protection_domain, 276 TRAPS) { 277 assert(FieldType::is_array(class_name), "must be array"); 278 Klass* k = NULL; 279 FieldArrayInfo fd; 280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 281 // of this call 282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 283 if (t == T_OBJECT) { 284 // naked oop "k" is OK here -- we assign back into it 285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 286 class_loader, 287 protection_domain, 288 CHECK_NULL); 289 if (k != NULL) { 290 k = k->array_klass(fd.dimension(), CHECK_NULL); 291 } 292 } else { 293 k = Universe::typeArrayKlassObj(t); 294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 295 } 296 return k; 297 } 298 299 300 // Must be called for any super-class or super-interface resolution 301 // during class definition to allow class circularity checking 302 // super-interface callers: 303 // parse_interfaces - for defineClass & jvmtiRedefineClasses 304 // super-class callers: 305 // ClassFileParser - for defineClass & jvmtiRedefineClasses 306 // load_shared_class - while loading a class from shared archive 307 // resolve_instance_class_or_null: 308 // via: handle_parallel_super_load 309 // when resolving a class that has an existing placeholder with 310 // a saved superclass [i.e. a defineClass is currently in progress] 311 // if another thread is trying to resolve the class, it must do 312 // super-class checks on its own thread to catch class circularity 313 // This last call is critical in class circularity checking for cases 314 // where classloading is delegated to different threads and the 315 // classloader lock is released. 316 // Take the case: Base->Super->Base 317 // 1. If thread T1 tries to do a defineClass of class Base 318 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 320 // so it tries to load Super 321 // 3. If we load the class internally, or user classloader uses same thread 322 // loadClassFromxxx or defineClass via parseClassFile Super ... 323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 325 // 3.4 calls resolve_super_or_fail Base 326 // 3.5 finds T1,Base -> throws class circularity 327 //OR 4. If T2 tries to resolve Super via defineClass Super ... 328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 331 // 4.4 finds T2, Super -> throws class circularity 332 // Must be called, even if superclass is null, since this is 333 // where the placeholder entry is created which claims this 334 // thread is loading this class/classloader. 335 // Be careful when modifying this code: once you have run 336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 337 // you need to find_and_remove it before returning. 338 // So be careful to not exit with a CHECK_ macro betweeen these calls. 339 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 340 Symbol* class_name, 341 Handle class_loader, 342 Handle protection_domain, 343 bool is_superclass, 344 TRAPS) { 345 #if INCLUDE_CDS 346 if (DumpSharedSpaces) { 347 // Special processing for CDS dump time. 348 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 349 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 350 if (k) { 351 return k; 352 } 353 } 354 #endif // INCLUDE_CDS 355 356 // Double-check, if child class is already loaded, just return super-class,interface 357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 358 // dictionary. 359 // Make sure there's a placeholder for the *child* before resolving. 360 // Used as a claim that this thread is currently loading superclass/classloader 361 // Used here for ClassCircularity checks and also for heap verification 362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 363 // Must check ClassCircularity before checking if super class is already loaded. 364 // 365 // We might not already have a placeholder if this child_name was 366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 367 // the name of the class might not be known until the stream is actually 368 // parsed. 369 // Bugs 4643874, 4715493 370 371 ClassLoaderData* loader_data = class_loader_data(class_loader); 372 Dictionary* dictionary = loader_data->dictionary(); 373 unsigned int d_hash = dictionary->compute_hash(child_name); 374 unsigned int p_hash = placeholders()->compute_hash(child_name); 375 int p_index = placeholders()->hash_to_index(p_hash); 376 // can't throw error holding a lock 377 bool child_already_loaded = false; 378 bool throw_circularity_error = false; 379 { 380 MutexLocker mu(SystemDictionary_lock, THREAD); 381 Klass* childk = find_class(d_hash, child_name, dictionary); 382 Klass* quicksuperk; 383 // to support // loading: if child done loading, just return superclass 384 // if class_name, & class_loader don't match: 385 // if initial define, SD update will give LinkageError 386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 387 // so we don't throw an exception here. 388 // see: nsk redefclass014 & java.lang.instrument Instrument032 389 if ((childk != NULL ) && (is_superclass) && 390 ((quicksuperk = childk->super()) != NULL) && 391 392 ((quicksuperk->name() == class_name) && 393 (quicksuperk->class_loader() == class_loader()))) { 394 return quicksuperk; 395 } else { 396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 398 throw_circularity_error = true; 399 } 400 } 401 if (!throw_circularity_error) { 402 // Be careful not to exit resolve_super 403 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 404 } 405 } 406 if (throw_circularity_error) { 407 ResourceMark rm(THREAD); 408 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 409 } 410 411 // java.lang.Object should have been found above 412 assert(class_name != NULL, "null super class for resolving"); 413 // Resolve the super class or interface, check results on return 414 Klass* superk = SystemDictionary::resolve_or_null(class_name, 415 class_loader, 416 protection_domain, 417 THREAD); 418 419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 420 // It is no longer necessary to keep the placeholder table alive until update_dictionary 421 // or error. GC used to walk the placeholder table as strong roots. 422 // The instanceKlass is kept alive because the class loader is on the stack, 423 // which keeps the loader_data alive, as well as all instanceKlasses in 424 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 425 { 426 MutexLocker mu(SystemDictionary_lock, THREAD); 427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 428 SystemDictionary_lock->notify_all(); 429 } 430 if (HAS_PENDING_EXCEPTION || superk == NULL) { 431 // can null superk 432 superk = handle_resolution_exception(class_name, true, superk, THREAD); 433 } 434 435 return superk; 436 } 437 438 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 439 Handle class_loader, 440 Handle protection_domain, 441 TRAPS) { 442 if(!has_checkPackageAccess()) return; 443 444 // Now we have to call back to java to check if the initating class has access 445 JavaValue result(T_VOID); 446 LogTarget(Debug, protectiondomain) lt; 447 if (lt.is_enabled()) { 448 ResourceMark rm; 449 // Print out trace information 450 LogStream ls(lt); 451 ls.print_cr("Checking package access"); 452 ls.print("class loader: "); class_loader()->print_value_on(&ls); 453 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls); 454 ls.print(" loading: "); klass->print_value_on(&ls); 455 ls.cr(); 456 } 457 458 // This handle and the class_loader handle passed in keeps this class from 459 // being unloaded through several GC points. 460 // The class_loader handle passed in is the initiating loader. 461 Handle mirror(THREAD, klass->java_mirror()); 462 463 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 464 JavaCalls::call_special(&result, 465 class_loader, 466 system_loader, 467 vmSymbols::checkPackageAccess_name(), 468 vmSymbols::class_protectiondomain_signature(), 469 mirror, 470 protection_domain, 471 THREAD); 472 473 if (HAS_PENDING_EXCEPTION) { 474 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 475 } else { 476 log_debug(protectiondomain)("granted"); 477 } 478 479 if (HAS_PENDING_EXCEPTION) return; 480 481 // If no exception has been thrown, we have validated the protection domain 482 // Insert the protection domain of the initiating class into the set. 483 { 484 ClassLoaderData* loader_data = class_loader_data(class_loader); 485 Dictionary* dictionary = loader_data->dictionary(); 486 487 Symbol* kn = klass->name(); 488 unsigned int d_hash = dictionary->compute_hash(kn); 489 490 MutexLocker mu(SystemDictionary_lock, THREAD); 491 int d_index = dictionary->hash_to_index(d_hash); 492 dictionary->add_protection_domain(d_index, d_hash, klass, 493 protection_domain, THREAD); 494 } 495 } 496 497 // We only get here if this thread finds that another thread 498 // has already claimed the placeholder token for the current operation, 499 // but that other thread either never owned or gave up the 500 // object lock 501 // Waits on SystemDictionary_lock to indicate placeholder table updated 502 // On return, caller must recheck placeholder table state 503 // 504 // We only get here if 505 // 1) custom classLoader, i.e. not bootstrap classloader 506 // 2) UnsyncloadClass not set 507 // 3) custom classLoader has broken the class loader objectLock 508 // so another thread got here in parallel 509 // 510 // lockObject must be held. 511 // Complicated dance due to lock ordering: 512 // Must first release the classloader object lock to 513 // allow initial definer to complete the class definition 514 // and to avoid deadlock 515 // Reclaim classloader lock object with same original recursion count 516 // Must release SystemDictionary_lock after notify, since 517 // class loader lock must be claimed before SystemDictionary_lock 518 // to prevent deadlocks 519 // 520 // The notify allows applications that did an untimed wait() on 521 // the classloader object lock to not hang. 522 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 523 assert_lock_strong(SystemDictionary_lock); 524 525 bool calledholdinglock 526 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 527 assert(calledholdinglock,"must hold lock for notify"); 528 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 529 ObjectSynchronizer::notifyall(lockObject, THREAD); 530 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 531 SystemDictionary_lock->wait(); 532 SystemDictionary_lock->unlock(); 533 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 534 SystemDictionary_lock->lock(); 535 } 536 537 // If the class in is in the placeholder table, class loading is in progress 538 // For cases where the application changes threads to load classes, it 539 // is critical to ClassCircularity detection that we try loading 540 // the superclass on the same thread internally, so we do parallel 541 // super class loading here. 542 // This also is critical in cases where the original thread gets stalled 543 // even in non-circularity situations. 544 // Note: must call resolve_super_or_fail even if null super - 545 // to force placeholder entry creation for this class for circularity detection 546 // Caller must check for pending exception 547 // Returns non-null Klass* if other thread has completed load 548 // and we are done, 549 // If return null Klass* and no pending exception, the caller must load the class 550 InstanceKlass* SystemDictionary::handle_parallel_super_load( 551 Symbol* name, Symbol* superclassname, Handle class_loader, 552 Handle protection_domain, Handle lockObject, TRAPS) { 553 554 ClassLoaderData* loader_data = class_loader_data(class_loader); 555 Dictionary* dictionary = loader_data->dictionary(); 556 unsigned int d_hash = dictionary->compute_hash(name); 557 unsigned int p_hash = placeholders()->compute_hash(name); 558 int p_index = placeholders()->hash_to_index(p_hash); 559 560 // superk is not used, resolve_super called for circularity check only 561 // This code is reached in two situations. One if this thread 562 // is loading the same class twice (e.g. ClassCircularity, or 563 // java.lang.instrument). 564 // The second is if another thread started the resolve_super first 565 // and has not yet finished. 566 // In both cases the original caller will clean up the placeholder 567 // entry on error. 568 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 569 superclassname, 570 class_loader, 571 protection_domain, 572 true, 573 CHECK_NULL); 574 575 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 576 // Serial class loaders and bootstrap classloader do wait for superclass loads 577 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 578 MutexLocker mu(SystemDictionary_lock, THREAD); 579 // Check if classloading completed while we were loading superclass or waiting 580 return find_class(d_hash, name, dictionary); 581 } 582 583 // must loop to both handle other placeholder updates 584 // and spurious notifications 585 bool super_load_in_progress = true; 586 PlaceholderEntry* placeholder; 587 while (super_load_in_progress) { 588 MutexLocker mu(SystemDictionary_lock, THREAD); 589 // Check if classloading completed while we were loading superclass or waiting 590 InstanceKlass* check = find_class(d_hash, name, dictionary); 591 if (check != NULL) { 592 // Klass is already loaded, so just return it 593 return check; 594 } else { 595 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 596 if (placeholder && placeholder->super_load_in_progress() ){ 597 // Before UnsyncloadClass: 598 // We only get here if the application has released the 599 // classloader lock when another thread was in the middle of loading a 600 // superclass/superinterface for this class, and now 601 // this thread is also trying to load this class. 602 // To minimize surprises, the first thread that started to 603 // load a class should be the one to complete the loading 604 // with the classfile it initially expected. 605 // This logic has the current thread wait once it has done 606 // all the superclass/superinterface loading it can, until 607 // the original thread completes the class loading or fails 608 // If it completes we will use the resulting InstanceKlass 609 // which we will find below in the systemDictionary. 610 // We also get here for parallel bootstrap classloader 611 if (class_loader.is_null()) { 612 SystemDictionary_lock->wait(); 613 } else { 614 double_lock_wait(lockObject, THREAD); 615 } 616 } else { 617 // If not in SD and not in PH, other thread's load must have failed 618 super_load_in_progress = false; 619 } 620 } 621 } 622 return NULL; 623 } 624 625 static void post_class_load_event(EventClassLoad* event, 626 const InstanceKlass* k, 627 const ClassLoaderData* init_cld) { 628 #if INCLUDE_TRACE 629 assert(event != NULL, "invariant"); 630 assert(k != NULL, "invariant"); 631 if (event->should_commit()) { 632 event->set_loadedClass(k); 633 event->set_definingClassLoader(k->class_loader_data()); 634 event->set_initiatingClassLoader(init_cld); 635 event->commit(); 636 } 637 #endif // INCLUDE_TRACE 638 } 639 640 static void class_define_event(InstanceKlass* k, 641 const ClassLoaderData* def_cld) { 642 #if INCLUDE_TRACE 643 EventClassDefine event; 644 if (event.should_commit()) { 645 event.set_definedClass(k); 646 event.set_definingClassLoader(def_cld); 647 event.commit(); 648 } 649 #endif // INCLUDE_TRACE 650 } 651 652 // Be careful when modifying this code: once you have run 653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 654 // you need to find_and_remove it before returning. 655 // So be careful to not exit with a CHECK_ macro betweeen these calls. 656 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 657 Handle class_loader, 658 Handle protection_domain, 659 TRAPS) { 660 assert(name != NULL && !FieldType::is_array(name) && 661 !FieldType::is_obj(name), "invalid class name"); 662 663 EventClassLoad class_load_start_event; 664 665 HandleMark hm(THREAD); 666 667 // Fix for 4474172; see evaluation for more details 668 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 669 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 670 Dictionary* dictionary = loader_data->dictionary(); 671 unsigned int d_hash = dictionary->compute_hash(name); 672 673 // Do lookup to see if class already exist and the protection domain 674 // has the right access 675 // This call uses find which checks protection domain already matches 676 // All subsequent calls use find_class, and set has_loaded_class so that 677 // before we return a result we call out to java to check for valid protection domain 678 // to allow returning the Klass* and add it to the pd_set if it is valid 679 { 680 Klass* probe = dictionary->find(d_hash, name, protection_domain); 681 if (probe != NULL) return probe; 682 } 683 684 // Non-bootstrap class loaders will call out to class loader and 685 // define via jvm/jni_DefineClass which will acquire the 686 // class loader object lock to protect against multiple threads 687 // defining the class in parallel by accident. 688 // This lock must be acquired here so the waiter will find 689 // any successful result in the SystemDictionary and not attempt 690 // the define 691 // ParallelCapable Classloaders and the bootstrap classloader, 692 // or all classloaders with UnsyncloadClass do not acquire lock here 693 bool DoObjectLock = true; 694 if (is_parallelCapable(class_loader)) { 695 DoObjectLock = false; 696 } 697 698 unsigned int p_hash = placeholders()->compute_hash(name); 699 int p_index = placeholders()->hash_to_index(p_hash); 700 701 // Class is not in SystemDictionary so we have to do loading. 702 // Make sure we are synchronized on the class loader before we proceed 703 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 704 check_loader_lock_contention(lockObject, THREAD); 705 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 706 707 // Check again (after locking) if class already exist in SystemDictionary 708 bool class_has_been_loaded = false; 709 bool super_load_in_progress = false; 710 bool havesupername = false; 711 InstanceKlass* k = NULL; 712 PlaceholderEntry* placeholder; 713 Symbol* superclassname = NULL; 714 715 { 716 MutexLocker mu(SystemDictionary_lock, THREAD); 717 InstanceKlass* check = find_class(d_hash, name, dictionary); 718 if (check != NULL) { 719 // Klass is already loaded, so just return it 720 class_has_been_loaded = true; 721 k = check; 722 } else { 723 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 724 if (placeholder && placeholder->super_load_in_progress()) { 725 super_load_in_progress = true; 726 if (placeholder->havesupername() == true) { 727 superclassname = placeholder->supername(); 728 havesupername = true; 729 } 730 } 731 } 732 } 733 734 // If the class is in the placeholder table, class loading is in progress 735 if (super_load_in_progress && havesupername==true) { 736 k = handle_parallel_super_load(name, 737 superclassname, 738 class_loader, 739 protection_domain, 740 lockObject, THREAD); 741 if (HAS_PENDING_EXCEPTION) { 742 return NULL; 743 } 744 if (k != NULL) { 745 class_has_been_loaded = true; 746 } 747 } 748 749 bool throw_circularity_error = false; 750 if (!class_has_been_loaded) { 751 bool load_instance_added = false; 752 753 // add placeholder entry to record loading instance class 754 // Five cases: 755 // All cases need to prevent modifying bootclasssearchpath 756 // in parallel with a classload of same classname 757 // Redefineclasses uses existence of the placeholder for the duration 758 // of the class load to prevent concurrent redefinition of not completely 759 // defined classes. 760 // case 1. traditional classloaders that rely on the classloader object lock 761 // - no other need for LOAD_INSTANCE 762 // case 2. traditional classloaders that break the classloader object lock 763 // as a deadlock workaround. Detection of this case requires that 764 // this check is done while holding the classloader object lock, 765 // and that lock is still held when calling classloader's loadClass. 766 // For these classloaders, we ensure that the first requestor 767 // completes the load and other requestors wait for completion. 768 // case 3. UnsyncloadClass - don't use objectLocker 769 // With this flag, we allow parallel classloading of a 770 // class/classloader pair 771 // case4. Bootstrap classloader - don't own objectLocker 772 // This classloader supports parallelism at the classloader level, 773 // but only allows a single load of a class/classloader pair. 774 // No performance benefit and no deadlock issues. 775 // case 5. parallelCapable user level classloaders - without objectLocker 776 // Allow parallel classloading of a class/classloader pair 777 778 { 779 MutexLocker mu(SystemDictionary_lock, THREAD); 780 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 781 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 782 if (oldprobe) { 783 // only need check_seen_thread once, not on each loop 784 // 6341374 java/lang/Instrument with -Xcomp 785 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 786 throw_circularity_error = true; 787 } else { 788 // case 1: traditional: should never see load_in_progress. 789 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 790 791 // case 4: bootstrap classloader: prevent futile classloading, 792 // wait on first requestor 793 if (class_loader.is_null()) { 794 SystemDictionary_lock->wait(); 795 } else { 796 // case 2: traditional with broken classloader lock. wait on first 797 // requestor. 798 double_lock_wait(lockObject, THREAD); 799 } 800 // Check if classloading completed while we were waiting 801 InstanceKlass* check = find_class(d_hash, name, dictionary); 802 if (check != NULL) { 803 // Klass is already loaded, so just return it 804 k = check; 805 class_has_been_loaded = true; 806 } 807 // check if other thread failed to load and cleaned up 808 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 809 } 810 } 811 } 812 } 813 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 814 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 815 // LOAD_INSTANCE in parallel 816 817 if (!throw_circularity_error && !class_has_been_loaded) { 818 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 819 load_instance_added = true; 820 // For class loaders that do not acquire the classloader object lock, 821 // if they did not catch another thread holding LOAD_INSTANCE, 822 // need a check analogous to the acquire ObjectLocker/find_class 823 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 824 // one final check if the load has already completed 825 // class loaders holding the ObjectLock shouldn't find the class here 826 InstanceKlass* check = find_class(d_hash, name, dictionary); 827 if (check != NULL) { 828 // Klass is already loaded, so return it after checking/adding protection domain 829 k = check; 830 class_has_been_loaded = true; 831 } 832 } 833 } 834 835 // must throw error outside of owning lock 836 if (throw_circularity_error) { 837 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 838 ResourceMark rm(THREAD); 839 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 840 } 841 842 if (!class_has_been_loaded) { 843 844 // Do actual loading 845 k = load_instance_class(name, class_loader, THREAD); 846 847 // For UnsyncloadClass only 848 // If they got a linkageError, check if a parallel class load succeeded. 849 // If it did, then for bytecode resolution the specification requires 850 // that we return the same result we did for the other thread, i.e. the 851 // successfully loaded InstanceKlass 852 // Should not get here for classloaders that support parallelism 853 // with the new cleaner mechanism, even with AllowParallelDefineClass 854 // Bootstrap goes through here to allow for an extra guarantee check 855 if (UnsyncloadClass || (class_loader.is_null())) { 856 if (k == NULL && HAS_PENDING_EXCEPTION 857 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 858 MutexLocker mu(SystemDictionary_lock, THREAD); 859 InstanceKlass* check = find_class(d_hash, name, dictionary); 860 if (check != NULL) { 861 // Klass is already loaded, so just use it 862 k = check; 863 CLEAR_PENDING_EXCEPTION; 864 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 865 } 866 } 867 } 868 869 // If everything was OK (no exceptions, no null return value), and 870 // class_loader is NOT the defining loader, do a little more bookkeeping. 871 if (!HAS_PENDING_EXCEPTION && k != NULL && 872 k->class_loader() != class_loader()) { 873 874 check_constraints(d_hash, k, class_loader, false, THREAD); 875 876 // Need to check for a PENDING_EXCEPTION again; check_constraints 877 // can throw and doesn't use the CHECK macro. 878 if (!HAS_PENDING_EXCEPTION) { 879 { // Grabbing the Compile_lock prevents systemDictionary updates 880 // during compilations. 881 MutexLocker mu(Compile_lock, THREAD); 882 update_dictionary(d_hash, p_index, p_hash, 883 k, class_loader, THREAD); 884 } 885 886 if (JvmtiExport::should_post_class_load()) { 887 Thread *thread = THREAD; 888 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 889 JvmtiExport::post_class_load((JavaThread *) thread, k); 890 } 891 } 892 } 893 } // load_instance_class 894 895 if (load_instance_added == true) { 896 // clean up placeholder entries for LOAD_INSTANCE success or error 897 // This brackets the SystemDictionary updates for both defining 898 // and initiating loaders 899 MutexLocker mu(SystemDictionary_lock, THREAD); 900 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 901 SystemDictionary_lock->notify_all(); 902 } 903 } 904 905 if (HAS_PENDING_EXCEPTION || k == NULL) { 906 return NULL; 907 } 908 909 post_class_load_event(&class_load_start_event, k, loader_data); 910 911 #ifdef ASSERT 912 { 913 ClassLoaderData* loader_data = k->class_loader_data(); 914 MutexLocker mu(SystemDictionary_lock, THREAD); 915 Klass* kk = find_class(name, loader_data); 916 assert(kk == k, "should be present in dictionary"); 917 } 918 #endif 919 920 // return if the protection domain in NULL 921 if (protection_domain() == NULL) return k; 922 923 // Check the protection domain has the right access 924 if (dictionary->is_valid_protection_domain(d_hash, name, 925 protection_domain)) { 926 return k; 927 } 928 929 // Verify protection domain. If it fails an exception is thrown 930 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 931 932 return k; 933 } 934 935 936 // This routine does not lock the system dictionary. 937 // 938 // Since readers don't hold a lock, we must make sure that system 939 // dictionary entries are only removed at a safepoint (when only one 940 // thread is running), and are added to in a safe way (all links must 941 // be updated in an MT-safe manner). 942 // 943 // Callers should be aware that an entry could be added just after 944 // _dictionary->bucket(index) is read here, so the caller will not see 945 // the new entry. 946 947 Klass* SystemDictionary::find(Symbol* class_name, 948 Handle class_loader, 949 Handle protection_domain, 950 TRAPS) { 951 952 // The result of this call should be consistent with the result 953 // of the call to resolve_instance_class_or_null(). 954 // See evaluation 6790209 and 4474172 for more details. 955 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 956 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 957 958 if (loader_data == NULL) { 959 // If the ClassLoaderData has not been setup, 960 // then the class loader has no entries in the dictionary. 961 return NULL; 962 } 963 964 Dictionary* dictionary = loader_data->dictionary(); 965 unsigned int d_hash = dictionary->compute_hash(class_name); 966 return dictionary->find(d_hash, class_name, 967 protection_domain); 968 } 969 970 971 // Look for a loaded instance or array klass by name. Do not do any loading. 972 // return NULL in case of error. 973 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 974 Handle class_loader, 975 Handle protection_domain, 976 TRAPS) { 977 Klass* k = NULL; 978 assert(class_name != NULL, "class name must be non NULL"); 979 980 if (FieldType::is_array(class_name)) { 981 // The name refers to an array. Parse the name. 982 // dimension and object_key in FieldArrayInfo are assigned as a 983 // side-effect of this call 984 FieldArrayInfo fd; 985 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 986 if (t != T_OBJECT) { 987 k = Universe::typeArrayKlassObj(t); 988 } else { 989 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 990 } 991 if (k != NULL) { 992 k = k->array_klass_or_null(fd.dimension()); 993 } 994 } else { 995 k = find(class_name, class_loader, protection_domain, THREAD); 996 } 997 return k; 998 } 999 1000 // Note: this method is much like resolve_from_stream, but 1001 // does not publish the classes via the SystemDictionary. 1002 // Handles unsafe_DefineAnonymousClass and redefineclasses 1003 // RedefinedClasses do not add to the class hierarchy 1004 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 1005 Handle class_loader, 1006 Handle protection_domain, 1007 ClassFileStream* st, 1008 const InstanceKlass* host_klass, 1009 GrowableArray<Handle>* cp_patches, 1010 TRAPS) { 1011 1012 EventClassLoad class_load_start_event; 1013 1014 ClassLoaderData* loader_data; 1015 if (host_klass != NULL) { 1016 // Create a new CLD for anonymous class, that uses the same class loader 1017 // as the host_klass 1018 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 1019 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 1020 } else { 1021 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1022 } 1023 1024 assert(st != NULL, "invariant"); 1025 assert(st->need_verify(), "invariant"); 1026 1027 // Parse stream and create a klass. 1028 // Note that we do this even though this klass might 1029 // already be present in the SystemDictionary, otherwise we would not 1030 // throw potential ClassFormatErrors. 1031 1032 InstanceKlass* k = KlassFactory::create_from_stream(st, 1033 class_name, 1034 loader_data, 1035 protection_domain, 1036 host_klass, 1037 cp_patches, 1038 CHECK_NULL); 1039 1040 if (host_klass != NULL && k != NULL) { 1041 // If it's anonymous, initialize it now, since nobody else will. 1042 1043 { 1044 MutexLocker mu_r(Compile_lock, THREAD); 1045 1046 // Add to class hierarchy, initialize vtables, and do possible 1047 // deoptimizations. 1048 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1049 1050 // But, do not add to dictionary. 1051 1052 // compiled code dependencies need to be validated anyway 1053 notice_modification(); 1054 } 1055 1056 // Rewrite and patch constant pool here. 1057 k->link_class(CHECK_NULL); 1058 if (cp_patches != NULL) { 1059 k->constants()->patch_resolved_references(cp_patches); 1060 } 1061 k->eager_initialize(CHECK_NULL); 1062 1063 // notify jvmti 1064 if (JvmtiExport::should_post_class_load()) { 1065 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1066 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1067 } 1068 1069 post_class_load_event(&class_load_start_event, k, loader_data); 1070 } 1071 assert(host_klass != NULL || NULL == cp_patches, 1072 "cp_patches only found with host_klass"); 1073 1074 return k; 1075 } 1076 1077 // Add a klass to the system from a stream (called by jni_DefineClass and 1078 // JVM_DefineClass). 1079 // Note: class_name can be NULL. In that case we do not know the name of 1080 // the class until we have parsed the stream. 1081 1082 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1083 Handle class_loader, 1084 Handle protection_domain, 1085 ClassFileStream* st, 1086 TRAPS) { 1087 #if INCLUDE_CDS 1088 ResourceMark rm(THREAD); 1089 if (DumpSharedSpaces && !class_loader.is_null() && 1090 !ArgumentsExt::using_AppCDS() && strcmp(class_name->as_C_string(), "Unnamed") != 0) { 1091 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed" 1092 // class, which is used by MethodHandles). 1093 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 1094 } 1095 #endif 1096 1097 HandleMark hm(THREAD); 1098 1099 // Classloaders that support parallelism, e.g. bootstrap classloader, 1100 // or all classloaders with UnsyncloadClass do not acquire lock here 1101 bool DoObjectLock = true; 1102 if (is_parallelCapable(class_loader)) { 1103 DoObjectLock = false; 1104 } 1105 1106 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1107 1108 // Make sure we are synchronized on the class loader before we proceed 1109 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1110 check_loader_lock_contention(lockObject, THREAD); 1111 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1112 1113 assert(st != NULL, "invariant"); 1114 1115 // Parse the stream and create a klass. 1116 // Note that we do this even though this klass might 1117 // already be present in the SystemDictionary, otherwise we would not 1118 // throw potential ClassFormatErrors. 1119 InstanceKlass* k = NULL; 1120 1121 #if INCLUDE_CDS 1122 if (!DumpSharedSpaces) { 1123 k = SystemDictionaryShared::lookup_from_stream(class_name, 1124 class_loader, 1125 protection_domain, 1126 st, 1127 CHECK_NULL); 1128 } 1129 #endif 1130 1131 if (k == NULL) { 1132 if (st->buffer() == NULL) { 1133 return NULL; 1134 } 1135 k = KlassFactory::create_from_stream(st, 1136 class_name, 1137 loader_data, 1138 protection_domain, 1139 NULL, // host_klass 1140 NULL, // cp_patches 1141 CHECK_NULL); 1142 } 1143 1144 assert(k != NULL, "no klass created"); 1145 Symbol* h_name = k->name(); 1146 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1147 1148 // Add class just loaded 1149 // If a class loader supports parallel classloading handle parallel define requests 1150 // find_or_define_instance_class may return a different InstanceKlass 1151 if (is_parallelCapable(class_loader)) { 1152 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1153 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1154 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1155 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1156 loader_data->add_to_deallocate_list(k); 1157 k = defined_k; 1158 } 1159 } else { 1160 define_instance_class(k, THREAD); 1161 } 1162 1163 // If defining the class throws an exception register 'k' for cleanup. 1164 if (HAS_PENDING_EXCEPTION) { 1165 assert(k != NULL, "Must have an instance klass here!"); 1166 loader_data->add_to_deallocate_list(k); 1167 return NULL; 1168 } 1169 1170 // Make sure we have an entry in the SystemDictionary on success 1171 debug_only( { 1172 MutexLocker mu(SystemDictionary_lock, THREAD); 1173 1174 Klass* check = find_class(h_name, k->class_loader_data()); 1175 assert(check == k, "should be present in the dictionary"); 1176 } ); 1177 1178 return k; 1179 } 1180 1181 #if INCLUDE_CDS 1182 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1183 int number_of_entries) { 1184 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1185 "bad shared dictionary size."); 1186 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1187 _shared_dictionary_size, t, number_of_entries); 1188 } 1189 1190 1191 // If there is a shared dictionary, then find the entry for the 1192 // given shared system class, if any. 1193 1194 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1195 if (shared_dictionary() != NULL) { 1196 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1197 int d_index = shared_dictionary()->hash_to_index(d_hash); 1198 1199 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1200 } else { 1201 return NULL; 1202 } 1203 } 1204 1205 1206 // Load a class from the shared spaces (found through the shared system 1207 // dictionary). Force the superclass and all interfaces to be loaded. 1208 // Update the class definition to include sibling classes and no 1209 // subclasses (yet). [Classes in the shared space are not part of the 1210 // object hierarchy until loaded.] 1211 1212 InstanceKlass* SystemDictionary::load_shared_class( 1213 Symbol* class_name, Handle class_loader, TRAPS) { 1214 InstanceKlass* ik = find_shared_class(class_name); 1215 // Make sure we only return the boot class for the NULL classloader. 1216 if (ik != NULL && 1217 ik->is_shared_boot_class() && class_loader.is_null()) { 1218 Handle protection_domain; 1219 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1220 } 1221 return NULL; 1222 } 1223 1224 // Check if a shared class can be loaded by the specific classloader: 1225 // 1226 // NULL classloader: 1227 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1228 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1229 // be defined in an unnamed module. 1230 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1231 InstanceKlass* ik, 1232 Handle class_loader, TRAPS) { 1233 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1234 "Cannot use sharing if java.base is patched"); 1235 ResourceMark rm; 1236 int path_index = ik->shared_classpath_index(); 1237 ClassLoaderData* loader_data = class_loader_data(class_loader); 1238 if (path_index < 0) { 1239 // path_index < 0 indicates that the class is intended for a custom loader 1240 // and should not be loaded by boot/platform/app loaders 1241 if (loader_data->is_builtin_class_loader_data()) { 1242 return false; 1243 } else { 1244 return true; 1245 } 1246 } 1247 SharedClassPathEntry* ent = 1248 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index); 1249 if (!Universe::is_module_initialized()) { 1250 assert(ent != NULL && ent->is_modules_image(), 1251 "Loading non-bootstrap classes before the module system is initialized"); 1252 assert(class_loader.is_null(), "sanity"); 1253 return true; 1254 } 1255 // Get the pkg_entry from the classloader 1256 TempNewSymbol pkg_name = NULL; 1257 PackageEntry* pkg_entry = NULL; 1258 ModuleEntry* mod_entry = NULL; 1259 const char* pkg_string = NULL; 1260 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1261 if (pkg_name != NULL) { 1262 pkg_string = pkg_name->as_C_string(); 1263 if (loader_data != NULL) { 1264 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1265 } 1266 if (pkg_entry != NULL) { 1267 mod_entry = pkg_entry->module(); 1268 } 1269 } 1270 1271 // If the archived class is from a module that has been patched at runtime, 1272 // the class cannot be loaded from the archive. 1273 if (mod_entry != NULL && mod_entry->is_patched()) { 1274 return false; 1275 } 1276 1277 if (class_loader.is_null()) { 1278 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1279 // The NULL classloader can load archived class originated from the 1280 // "modules" jimage and the -Xbootclasspath/a. For class from the 1281 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1282 // by the NULL classloader. 1283 if (mod_entry != NULL) { 1284 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1285 // ModuleEntry's location agrees with the archived class' origination. 1286 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1287 return true; // Module class from the "module" jimage 1288 } 1289 } 1290 1291 // If the archived class is not from the "module" jimage, the class can be 1292 // loaded by the NULL classloader if 1293 // 1294 // 1. the class is from the unamed package 1295 // 2. or, the class is not from a module defined in the NULL classloader 1296 // 3. or, the class is from an unamed module 1297 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1298 // the class is from the -Xbootclasspath/a 1299 if (pkg_string == NULL || 1300 pkg_entry == NULL || 1301 pkg_entry->in_unnamed_module()) { 1302 assert(mod_entry == NULL || 1303 mod_entry == loader_data->unnamed_module(), 1304 "the unnamed module is not defined in the classloader"); 1305 return true; 1306 } 1307 } 1308 return false; 1309 } else { 1310 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1311 ik, class_loader, pkg_string, pkg_name, 1312 pkg_entry, mod_entry, CHECK_(false)); 1313 return res; 1314 } 1315 } 1316 1317 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1318 Handle class_loader, 1319 Handle protection_domain, TRAPS) { 1320 1321 if (ik != NULL) { 1322 Symbol* class_name = ik->name(); 1323 1324 bool visible = is_shared_class_visible( 1325 class_name, ik, class_loader, CHECK_NULL); 1326 if (!visible) { 1327 return NULL; 1328 } 1329 1330 // Resolve the superclass and interfaces. They must be the same 1331 // as in dump time, because the layout of <ik> depends on 1332 // the specific layout of ik->super() and ik->local_interfaces(). 1333 // 1334 // If unexpected superclass or interfaces are found, we cannot 1335 // load <ik> from the shared archive. 1336 1337 if (ik->super() != NULL) { 1338 Symbol* cn = ik->super()->name(); 1339 Klass *s = resolve_super_or_fail(class_name, cn, 1340 class_loader, protection_domain, true, CHECK_NULL); 1341 if (s != ik->super()) { 1342 // The dynamically resolved super class is not the same as the one we used during dump time, 1343 // so we cannot use ik. 1344 return NULL; 1345 } else { 1346 assert(s->is_shared(), "must be"); 1347 } 1348 } 1349 1350 Array<Klass*>* interfaces = ik->local_interfaces(); 1351 int num_interfaces = interfaces->length(); 1352 for (int index = 0; index < num_interfaces; index++) { 1353 Klass* k = interfaces->at(index); 1354 Symbol* name = k->name(); 1355 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1356 if (k != i) { 1357 // The dynamically resolved interface class is not the same as the one we used during dump time, 1358 // so we cannot use ik. 1359 return NULL; 1360 } else { 1361 assert(i->is_shared(), "must be"); 1362 } 1363 } 1364 1365 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1366 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1367 if (new_ik != NULL) { 1368 // The class is changed by CFLH. Return the new class. The shared class is 1369 // not used. 1370 return new_ik; 1371 } 1372 1373 // Adjust methods to recover missing data. They need addresses for 1374 // interpreter entry points and their default native method address 1375 // must be reset. 1376 1377 // Updating methods must be done under a lock so multiple 1378 // threads don't update these in parallel 1379 // 1380 // Shared classes are all currently loaded by either the bootstrap or 1381 // internal parallel class loaders, so this will never cause a deadlock 1382 // on a custom class loader lock. 1383 1384 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1385 { 1386 HandleMark hm(THREAD); 1387 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1388 check_loader_lock_contention(lockObject, THREAD); 1389 ObjectLocker ol(lockObject, THREAD, true); 1390 // prohibited package check assumes all classes loaded from archive call 1391 // restore_unshareable_info which calls ik->set_package() 1392 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1393 } 1394 1395 ik->print_class_load_logging(loader_data, NULL, NULL); 1396 1397 // For boot loader, ensure that GetSystemPackage knows that a class in this 1398 // package was loaded. 1399 if (class_loader.is_null()) { 1400 int path_index = ik->shared_classpath_index(); 1401 ResourceMark rm; 1402 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1403 } 1404 1405 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1406 // Only dump the classes that can be stored into CDS archive 1407 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1408 ResourceMark rm(THREAD); 1409 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1410 classlist_file->flush(); 1411 } 1412 } 1413 1414 // notify a class loaded from shared object 1415 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1416 } 1417 1418 ik->set_has_passed_fingerprint_check(false); 1419 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1420 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1421 uint64_t cds_fp = ik->get_stored_fingerprint(); 1422 if (aot_fp != 0 && aot_fp == cds_fp) { 1423 // This class matches with a class saved in an AOT library 1424 ik->set_has_passed_fingerprint_check(true); 1425 } else { 1426 ResourceMark rm; 1427 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1428 } 1429 } 1430 return ik; 1431 } 1432 1433 void SystemDictionary::clear_invoke_method_table() { 1434 SymbolPropertyEntry* spe = NULL; 1435 for (int index = 0; index < _invoke_method_table->table_size(); index++) { 1436 SymbolPropertyEntry* p = _invoke_method_table->bucket(index); 1437 while (p != NULL) { 1438 spe = p; 1439 p = p->next(); 1440 _invoke_method_table->free_entry(spe); 1441 } 1442 } 1443 } 1444 #endif // INCLUDE_CDS 1445 1446 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1447 1448 if (class_loader.is_null()) { 1449 ResourceMark rm; 1450 PackageEntry* pkg_entry = NULL; 1451 bool search_only_bootloader_append = false; 1452 ClassLoaderData *loader_data = class_loader_data(class_loader); 1453 1454 // Find the package in the boot loader's package entry table. 1455 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1456 if (pkg_name != NULL) { 1457 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1458 } 1459 1460 // Prior to attempting to load the class, enforce the boot loader's 1461 // visibility boundaries. 1462 if (!Universe::is_module_initialized()) { 1463 // During bootstrapping, prior to module initialization, any 1464 // class attempting to be loaded must be checked against the 1465 // java.base packages in the boot loader's PackageEntryTable. 1466 // No class outside of java.base is allowed to be loaded during 1467 // this bootstrapping window. 1468 if (!DumpSharedSpaces) { 1469 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1470 // Class is either in the unnamed package or in 1471 // a named package within the unnamed module. Either 1472 // case is outside of java.base, do not attempt to 1473 // load the class post java.base definition. If 1474 // java.base has not been defined, let the class load 1475 // and its package will be checked later by 1476 // ModuleEntryTable::verify_javabase_packages. 1477 if (ModuleEntryTable::javabase_defined()) { 1478 return NULL; 1479 } 1480 } else { 1481 // Check that the class' package is defined within java.base. 1482 ModuleEntry* mod_entry = pkg_entry->module(); 1483 Symbol* mod_entry_name = mod_entry->name(); 1484 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1485 return NULL; 1486 } 1487 } 1488 } 1489 } else { 1490 // After the module system has been initialized, check if the class' 1491 // package is in a module defined to the boot loader. 1492 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1493 // Class is either in the unnamed package, in a named package 1494 // within a module not defined to the boot loader or in a 1495 // a named package within the unnamed module. In all cases, 1496 // limit visibility to search for the class only in the boot 1497 // loader's append path. 1498 search_only_bootloader_append = true; 1499 } 1500 } 1501 1502 // Prior to bootstrapping's module initialization, never load a class outside 1503 // of the boot loader's module path 1504 assert(Universe::is_module_initialized() || DumpSharedSpaces || 1505 !search_only_bootloader_append, 1506 "Attempt to load a class outside of boot loader's module path"); 1507 1508 // Search the shared system dictionary for classes preloaded into the 1509 // shared spaces. 1510 InstanceKlass* k = NULL; 1511 { 1512 #if INCLUDE_CDS 1513 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1514 k = load_shared_class(class_name, class_loader, THREAD); 1515 #endif 1516 } 1517 1518 if (k == NULL) { 1519 // Use VM class loader 1520 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1521 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1522 } 1523 1524 // find_or_define_instance_class may return a different InstanceKlass 1525 if (k != NULL) { 1526 InstanceKlass* defined_k = 1527 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1528 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1529 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1530 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1531 loader_data->add_to_deallocate_list(k); 1532 k = defined_k; 1533 } else if (HAS_PENDING_EXCEPTION) { 1534 loader_data->add_to_deallocate_list(k); 1535 return NULL; 1536 } 1537 } 1538 return k; 1539 } else { 1540 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1541 ResourceMark rm(THREAD); 1542 1543 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1544 JavaThread* jt = (JavaThread*) THREAD; 1545 1546 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1547 ClassLoader::perf_app_classload_selftime(), 1548 ClassLoader::perf_app_classload_count(), 1549 jt->get_thread_stat()->perf_recursion_counts_addr(), 1550 jt->get_thread_stat()->perf_timers_addr(), 1551 PerfClassTraceTime::CLASS_LOAD); 1552 1553 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1554 // Translate to external class name format, i.e., convert '/' chars to '.' 1555 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1556 1557 JavaValue result(T_OBJECT); 1558 1559 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1560 1561 // Call public unsynchronized loadClass(String) directly for all class loaders 1562 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1563 // acquire a class-name based lock rather than the class loader object lock. 1564 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1565 // so the call to loadClassInternal() was not required. 1566 // 1567 // UnsyncloadClass flag means both call loadClass(String) and do 1568 // not acquire the class loader lock even for class loaders that are 1569 // not parallelCapable. This was a risky transitional 1570 // flag for diagnostic purposes only. It is risky to call 1571 // custom class loaders without synchronization. 1572 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1573 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1574 // Do NOT assume this will be supported in future releases. 1575 // 1576 // Added MustCallLoadClassInternal in case we discover in the field 1577 // a customer that counts on this call 1578 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1579 JavaCalls::call_special(&result, 1580 class_loader, 1581 spec_klass, 1582 vmSymbols::loadClassInternal_name(), 1583 vmSymbols::string_class_signature(), 1584 string, 1585 CHECK_NULL); 1586 } else { 1587 JavaCalls::call_virtual(&result, 1588 class_loader, 1589 spec_klass, 1590 vmSymbols::loadClass_name(), 1591 vmSymbols::string_class_signature(), 1592 string, 1593 CHECK_NULL); 1594 } 1595 1596 assert(result.get_type() == T_OBJECT, "just checking"); 1597 oop obj = (oop) result.get_jobject(); 1598 1599 // Primitive classes return null since forName() can not be 1600 // used to obtain any of the Class objects representing primitives or void 1601 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1602 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1603 // For user defined Java class loaders, check that the name returned is 1604 // the same as that requested. This check is done for the bootstrap 1605 // loader when parsing the class file. 1606 if (class_name == k->name()) { 1607 return k; 1608 } 1609 } 1610 // Class is not found or has the wrong name, return NULL 1611 return NULL; 1612 } 1613 } 1614 1615 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1616 1617 HandleMark hm(THREAD); 1618 ClassLoaderData* loader_data = k->class_loader_data(); 1619 Handle class_loader_h(THREAD, loader_data->class_loader()); 1620 1621 // for bootstrap and other parallel classloaders don't acquire lock, 1622 // use placeholder token 1623 // If a parallelCapable class loader calls define_instance_class instead of 1624 // find_or_define_instance_class to get here, we have a timing 1625 // hole with systemDictionary updates and check_constraints 1626 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1627 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1628 compute_loader_lock_object(class_loader_h, THREAD)), 1629 "define called without lock"); 1630 } 1631 1632 // Check class-loading constraints. Throw exception if violation is detected. 1633 // Grabs and releases SystemDictionary_lock 1634 // The check_constraints/find_class call and update_dictionary sequence 1635 // must be "atomic" for a specific class/classloader pair so we never 1636 // define two different instanceKlasses for that class/classloader pair. 1637 // Existing classloaders will call define_instance_class with the 1638 // classloader lock held 1639 // Parallel classloaders will call find_or_define_instance_class 1640 // which will require a token to perform the define class 1641 Symbol* name_h = k->name(); 1642 Dictionary* dictionary = loader_data->dictionary(); 1643 unsigned int d_hash = dictionary->compute_hash(name_h); 1644 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1645 1646 // Register class just loaded with class loader (placed in Vector) 1647 // Note we do this before updating the dictionary, as this can 1648 // fail with an OutOfMemoryError (if it does, we will *not* put this 1649 // class in the dictionary and will not update the class hierarchy). 1650 // JVMTI FollowReferences needs to find the classes this way. 1651 if (k->class_loader() != NULL) { 1652 methodHandle m(THREAD, Universe::loader_addClass_method()); 1653 JavaValue result(T_VOID); 1654 JavaCallArguments args(class_loader_h); 1655 args.push_oop(Handle(THREAD, k->java_mirror())); 1656 JavaCalls::call(&result, m, &args, CHECK); 1657 } 1658 1659 // Add the new class. We need recompile lock during update of CHA. 1660 { 1661 unsigned int p_hash = placeholders()->compute_hash(name_h); 1662 int p_index = placeholders()->hash_to_index(p_hash); 1663 1664 MutexLocker mu_r(Compile_lock, THREAD); 1665 1666 // Add to class hierarchy, initialize vtables, and do possible 1667 // deoptimizations. 1668 add_to_hierarchy(k, CHECK); // No exception, but can block 1669 1670 // Add to systemDictionary - so other classes can see it. 1671 // Grabs and releases SystemDictionary_lock 1672 update_dictionary(d_hash, p_index, p_hash, 1673 k, class_loader_h, THREAD); 1674 } 1675 k->eager_initialize(THREAD); 1676 1677 // notify jvmti 1678 if (JvmtiExport::should_post_class_load()) { 1679 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1680 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1681 1682 } 1683 class_define_event(k, loader_data); 1684 } 1685 1686 // Support parallel classloading 1687 // All parallel class loaders, including bootstrap classloader 1688 // lock a placeholder entry for this class/class_loader pair 1689 // to allow parallel defines of different classes for this class loader 1690 // With AllowParallelDefine flag==true, in case they do not synchronize around 1691 // FindLoadedClass/DefineClass, calls, we check for parallel 1692 // loading for them, wait if a defineClass is in progress 1693 // and return the initial requestor's results 1694 // This flag does not apply to the bootstrap classloader. 1695 // With AllowParallelDefine flag==false, call through to define_instance_class 1696 // which will throw LinkageError: duplicate class definition. 1697 // False is the requested default. 1698 // For better performance, the class loaders should synchronize 1699 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1700 // potentially waste time reading and parsing the bytestream. 1701 // Note: VM callers should ensure consistency of k/class_name,class_loader 1702 // Be careful when modifying this code: once you have run 1703 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1704 // you need to find_and_remove it before returning. 1705 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1706 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1707 InstanceKlass* k, TRAPS) { 1708 1709 Symbol* name_h = k->name(); // passed in class_name may be null 1710 ClassLoaderData* loader_data = class_loader_data(class_loader); 1711 Dictionary* dictionary = loader_data->dictionary(); 1712 1713 unsigned int d_hash = dictionary->compute_hash(name_h); 1714 1715 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1716 unsigned int p_hash = placeholders()->compute_hash(name_h); 1717 int p_index = placeholders()->hash_to_index(p_hash); 1718 PlaceholderEntry* probe; 1719 1720 { 1721 MutexLocker mu(SystemDictionary_lock, THREAD); 1722 // First check if class already defined 1723 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1724 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1725 if (check != NULL) { 1726 return check; 1727 } 1728 } 1729 1730 // Acquire define token for this class/classloader 1731 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1732 // Wait if another thread defining in parallel 1733 // All threads wait - even those that will throw duplicate class: otherwise 1734 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1735 // if other thread has not finished updating dictionary 1736 while (probe->definer() != NULL) { 1737 SystemDictionary_lock->wait(); 1738 } 1739 // Only special cases allow parallel defines and can use other thread's results 1740 // Other cases fall through, and may run into duplicate defines 1741 // caught by finding an entry in the SystemDictionary 1742 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1743 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1744 SystemDictionary_lock->notify_all(); 1745 #ifdef ASSERT 1746 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1747 assert(check != NULL, "definer missed recording success"); 1748 #endif 1749 return probe->instance_klass(); 1750 } else { 1751 // This thread will define the class (even if earlier thread tried and had an error) 1752 probe->set_definer(THREAD); 1753 } 1754 } 1755 1756 define_instance_class(k, THREAD); 1757 1758 Handle linkage_exception = Handle(); // null handle 1759 1760 // definer must notify any waiting threads 1761 { 1762 MutexLocker mu(SystemDictionary_lock, THREAD); 1763 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1764 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1765 if (probe != NULL) { 1766 if (HAS_PENDING_EXCEPTION) { 1767 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1768 CLEAR_PENDING_EXCEPTION; 1769 } else { 1770 probe->set_instance_klass(k); 1771 } 1772 probe->set_definer(NULL); 1773 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1774 SystemDictionary_lock->notify_all(); 1775 } 1776 } 1777 1778 // Can't throw exception while holding lock due to rank ordering 1779 if (linkage_exception() != NULL) { 1780 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1781 } 1782 1783 return k; 1784 } 1785 1786 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1787 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1788 if (class_loader.is_null()) { 1789 return Handle(THREAD, _system_loader_lock_obj); 1790 } else { 1791 return class_loader; 1792 } 1793 } 1794 1795 // This method is added to check how often we have to wait to grab loader 1796 // lock. The results are being recorded in the performance counters defined in 1797 // ClassLoader::_sync_systemLoaderLockContentionRate and 1798 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1799 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1800 if (!UsePerfData) { 1801 return; 1802 } 1803 1804 assert(!loader_lock.is_null(), "NULL lock object"); 1805 1806 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1807 == ObjectSynchronizer::owner_other) { 1808 // contention will likely happen, so increment the corresponding 1809 // contention counter. 1810 if (loader_lock() == _system_loader_lock_obj) { 1811 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1812 } else { 1813 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1814 } 1815 } 1816 } 1817 1818 // ---------------------------------------------------------------------------- 1819 // Lookup 1820 1821 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1822 Symbol* class_name, 1823 Dictionary* dictionary) { 1824 assert_locked_or_safepoint(SystemDictionary_lock); 1825 int index = dictionary->hash_to_index(hash); 1826 return dictionary->find_class(index, hash, class_name); 1827 } 1828 1829 1830 // Basic find on classes in the midst of being loaded 1831 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1832 ClassLoaderData* loader_data) { 1833 assert_locked_or_safepoint(SystemDictionary_lock); 1834 unsigned int p_hash = placeholders()->compute_hash(class_name); 1835 int p_index = placeholders()->hash_to_index(p_hash); 1836 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1837 } 1838 1839 1840 // Used for assertions and verification only 1841 // Precalculating the hash and index is an optimization because there are many lookups 1842 // before adding the class. 1843 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1844 assert_locked_or_safepoint(SystemDictionary_lock); 1845 #ifndef ASSERT 1846 guarantee(VerifyBeforeGC || 1847 VerifyDuringGC || 1848 VerifyBeforeExit || 1849 VerifyDuringStartup || 1850 VerifyAfterGC, "too expensive"); 1851 #endif 1852 1853 Dictionary* dictionary = loader_data->dictionary(); 1854 unsigned int d_hash = dictionary->compute_hash(class_name); 1855 return find_class(d_hash, class_name, dictionary); 1856 } 1857 1858 1859 // ---------------------------------------------------------------------------- 1860 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1861 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1862 // before a new class is used. 1863 1864 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1865 assert(k != NULL, "just checking"); 1866 assert_locked_or_safepoint(Compile_lock); 1867 1868 // Link into hierachy. Make sure the vtables are initialized before linking into 1869 k->append_to_sibling_list(); // add to superklass/sibling list 1870 k->process_interfaces(THREAD); // handle all "implements" declarations 1871 k->set_init_state(InstanceKlass::loaded); 1872 // Now flush all code that depended on old class hierarchy. 1873 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1874 // Also, first reinitialize vtable because it may have gotten out of synch 1875 // while the new class wasn't connected to the class hierarchy. 1876 CodeCache::flush_dependents_on(k); 1877 } 1878 1879 // ---------------------------------------------------------------------------- 1880 // GC support 1881 1882 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1883 roots_oops_do(blk, NULL); 1884 } 1885 1886 1887 #ifdef ASSERT 1888 class VerifySDReachableAndLiveClosure : public OopClosure { 1889 private: 1890 BoolObjectClosure* _is_alive; 1891 1892 template <class T> void do_oop_work(T* p) { 1893 oop obj = oopDesc::load_decode_heap_oop(p); 1894 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live"); 1895 } 1896 1897 public: 1898 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1899 1900 virtual void do_oop(oop* p) { do_oop_work(p); } 1901 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1902 }; 1903 #endif 1904 1905 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1906 // Note: anonymous classes are not in the SD. 1907 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, 1908 GCTimer* gc_timer, 1909 bool do_cleaning) { 1910 1911 1912 bool unloading_occurred; 1913 { 1914 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1915 1916 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1917 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, 1918 do_cleaning); 1919 } 1920 1921 if (unloading_occurred) { 1922 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1923 constraints()->purge_loader_constraints(); 1924 resolution_errors()->purge_resolution_errors(); 1925 } 1926 1927 { 1928 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1929 // Oops referenced by the protection domain cache table may get unreachable independently 1930 // of the class loader (eg. cached protection domain oops). So we need to 1931 // explicitly unlink them here. 1932 _pd_cache_table->unlink(is_alive); 1933 1934 #ifdef ASSERT 1935 VerifySDReachableAndLiveClosure cl(is_alive); 1936 _pd_cache_table->oops_do(&cl); 1937 #endif 1938 } 1939 1940 if (do_cleaning) { 1941 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1942 ResolvedMethodTable::unlink(is_alive); 1943 } 1944 1945 return unloading_occurred; 1946 } 1947 1948 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1949 strong->do_oop(&_java_system_loader); 1950 strong->do_oop(&_java_platform_loader); 1951 strong->do_oop(&_system_loader_lock_obj); 1952 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) 1953 1954 // Do strong roots marking if the closures are the same. 1955 if (strong == weak || !ClassUnloading) { 1956 // Only the protection domain oops contain references into the heap. Iterate 1957 // over all of them. 1958 _pd_cache_table->oops_do(strong); 1959 } else { 1960 if (weak != NULL) { 1961 _pd_cache_table->oops_do(weak); 1962 } 1963 } 1964 1965 // Visit extra methods 1966 invoke_method_table()->oops_do(strong); 1967 1968 if (weak != NULL) { 1969 ResolvedMethodTable::oops_do(weak); 1970 } 1971 } 1972 1973 void SystemDictionary::oops_do(OopClosure* f) { 1974 f->do_oop(&_java_system_loader); 1975 f->do_oop(&_java_platform_loader); 1976 f->do_oop(&_system_loader_lock_obj); 1977 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1978 1979 // Only the protection domain oops contain references into the heap. Iterate 1980 // over all of them. 1981 _pd_cache_table->oops_do(f); 1982 1983 // Visit extra methods 1984 invoke_method_table()->oops_do(f); 1985 1986 ResolvedMethodTable::oops_do(f); 1987 } 1988 1989 // CDS: scan and relocate all classes in the system dictionary. 1990 void SystemDictionary::classes_do(MetaspaceClosure* it) { 1991 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); 1992 } 1993 1994 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1995 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1996 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1997 it->push(well_known_klass_addr((WKID)id)); 1998 } 1999 } 2000 2001 void SystemDictionary::methods_do(void f(Method*)) { 2002 // Walk methods in loaded classes 2003 ClassLoaderDataGraph::methods_do(f); 2004 // Walk method handle intrinsics 2005 invoke_method_table()->methods_do(f); 2006 } 2007 2008 class RemoveClassesClosure : public CLDClosure { 2009 public: 2010 void do_cld(ClassLoaderData* cld) { 2011 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 2012 cld->dictionary()->remove_classes_in_error_state(); 2013 } 2014 } 2015 }; 2016 2017 void SystemDictionary::remove_classes_in_error_state() { 2018 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 2019 RemoveClassesClosure rcc; 2020 ClassLoaderDataGraph::cld_do(&rcc); 2021 } 2022 2023 // ---------------------------------------------------------------------------- 2024 // Lazily load klasses 2025 2026 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 2027 // if multiple threads calling this function, only one thread will load 2028 // the class. The other threads will find the loaded version once the 2029 // class is loaded. 2030 Klass* aos = _abstract_ownable_synchronizer_klass; 2031 if (aos == NULL) { 2032 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 2033 // Force a fence to prevent any read before the write completes 2034 OrderAccess::fence(); 2035 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); 2036 } 2037 } 2038 2039 // ---------------------------------------------------------------------------- 2040 // Initialization 2041 2042 void SystemDictionary::initialize(TRAPS) { 2043 // Allocate arrays 2044 _placeholders = new PlaceholderTable(_placeholder_table_size); 2045 _number_of_modifications = 0; 2046 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 2047 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 2048 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 2049 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 2050 2051 // Allocate private object used as system class loader lock 2052 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 2053 // Initialize basic classes 2054 initialize_preloaded_classes(CHECK); 2055 } 2056 2057 // Compact table of directions on the initialization of klasses: 2058 static const short wk_init_info[] = { 2059 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 2060 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 2061 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 2062 | (int)SystemDictionary::option ), 2063 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 2064 #undef WK_KLASS_INIT_INFO 2065 0 2066 }; 2067 2068 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 2069 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2070 int info = wk_init_info[id - FIRST_WKID]; 2071 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2072 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 2073 InstanceKlass** klassp = &_well_known_klasses[id]; 2074 2075 bool must_load; 2076 #if INCLUDE_JVMCI 2077 if (EnableJVMCI) { 2078 // If JVMCI is enabled we require its classes to be found. 2079 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 2080 } else 2081 #endif 2082 { 2083 must_load = (init_opt < SystemDictionary::Opt); 2084 } 2085 2086 if ((*klassp) == NULL) { 2087 Klass* k; 2088 if (must_load) { 2089 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 2090 } else { 2091 k = resolve_or_null(symbol, CHECK_0); // load optional klass 2092 } 2093 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 2094 } 2095 return ((*klassp) != NULL); 2096 } 2097 2098 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 2099 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 2100 for (int id = (int)start_id; id < (int)limit_id; id++) { 2101 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2102 int info = wk_init_info[id - FIRST_WKID]; 2103 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2104 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 2105 2106 initialize_wk_klass((WKID)id, opt, CHECK); 2107 } 2108 2109 // move the starting value forward to the limit: 2110 start_id = limit_id; 2111 } 2112 2113 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 2114 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 2115 2116 // Create the ModuleEntry for java.base. This call needs to be done here, 2117 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 2118 ClassLoader::classLoader_init2(CHECK); 2119 2120 // Preload commonly used klasses 2121 WKID scan = FIRST_WKID; 2122 // first do Object, then String, Class 2123 #if INCLUDE_CDS 2124 if (UseSharedSpaces) { 2125 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2126 // Initialize the constant pool for the Object_class 2127 Object_klass()->constants()->restore_unshareable_info(CHECK); 2128 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2129 } else 2130 #endif 2131 { 2132 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2133 } 2134 2135 // Calculate offsets for String and Class classes since they are loaded and 2136 // can be used after this point. 2137 java_lang_String::compute_offsets(); 2138 java_lang_Class::compute_offsets(); 2139 2140 // Fixup mirrors for classes loaded before java.lang.Class. 2141 // These calls iterate over the objects currently in the perm gen 2142 // so calling them at this point is matters (not before when there 2143 // are fewer objects and not later after there are more objects 2144 // in the perm gen. 2145 Universe::initialize_basic_type_mirrors(CHECK); 2146 Universe::fixup_mirrors(CHECK); 2147 2148 // do a bunch more: 2149 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2150 2151 // Preload ref klasses and set reference types 2152 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2153 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2154 2155 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2156 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2157 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2158 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2159 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2160 2161 // JSR 292 classes 2162 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2163 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2164 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 2165 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 2166 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); 2167 2168 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2169 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2170 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2171 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2172 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2173 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2174 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2175 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2176 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2177 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2178 2179 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 2180 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 2181 _has_loadClassInternal = (method != NULL); 2182 } 2183 { // Compute whether we should use checkPackageAccess or NOT 2184 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2185 _has_checkPackageAccess = (method != NULL); 2186 } 2187 } 2188 2189 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2190 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2191 BasicType SystemDictionary::box_klass_type(Klass* k) { 2192 assert(k != NULL, ""); 2193 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2194 if (_box_klasses[i] == k) 2195 return (BasicType)i; 2196 } 2197 return T_OBJECT; 2198 } 2199 2200 // Constraints on class loaders. The details of the algorithm can be 2201 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2202 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2203 // that the dictionary needs to maintain a set of contraints that 2204 // must be satisfied by all classes in the dictionary. 2205 // if defining is true, then LinkageError if already in dictionary 2206 // if initiating loader, then ok if InstanceKlass matches existing entry 2207 2208 void SystemDictionary::check_constraints(unsigned int d_hash, 2209 InstanceKlass* k, 2210 Handle class_loader, bool defining, 2211 TRAPS) { 2212 const char *linkage_error1 = NULL; 2213 const char *linkage_error2 = NULL; 2214 { 2215 Symbol* name = k->name(); 2216 ClassLoaderData *loader_data = class_loader_data(class_loader); 2217 2218 MutexLocker mu(SystemDictionary_lock, THREAD); 2219 2220 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2221 if (check != NULL) { 2222 // if different InstanceKlass - duplicate class definition, 2223 // else - ok, class loaded by a different thread in parallel, 2224 // we should only have found it if it was done loading and ok to use 2225 // dictionary only holds instance classes, placeholders 2226 // also holds array classes 2227 2228 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2229 if ((defining == true) || (k != check)) { 2230 linkage_error1 = "loader (instance of "; 2231 linkage_error2 = "): attempted duplicate class definition for name: \""; 2232 } else { 2233 return; 2234 } 2235 } 2236 2237 #ifdef ASSERT 2238 Symbol* ph_check = find_placeholder(name, loader_data); 2239 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2240 #endif 2241 2242 if (linkage_error1 == NULL) { 2243 if (constraints()->check_or_update(k, class_loader, name) == false) { 2244 linkage_error1 = "loader constraint violation: loader (instance of "; 2245 linkage_error2 = ") previously initiated loading for a different type with name \""; 2246 } 2247 } 2248 } 2249 2250 // Throw error now if needed (cannot throw while holding 2251 // SystemDictionary_lock because of rank ordering) 2252 2253 if (linkage_error1) { 2254 ResourceMark rm(THREAD); 2255 const char* class_loader_name = loader_name(class_loader()); 2256 char* type_name = k->name()->as_C_string(); 2257 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) + 2258 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte. 2259 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2260 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name); 2261 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2262 } 2263 } 2264 2265 2266 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2267 // have been called. 2268 void SystemDictionary::update_dictionary(unsigned int d_hash, 2269 int p_index, unsigned int p_hash, 2270 InstanceKlass* k, 2271 Handle class_loader, 2272 TRAPS) { 2273 // Compile_lock prevents systemDictionary updates during compilations 2274 assert_locked_or_safepoint(Compile_lock); 2275 Symbol* name = k->name(); 2276 ClassLoaderData *loader_data = class_loader_data(class_loader); 2277 2278 { 2279 MutexLocker mu1(SystemDictionary_lock, THREAD); 2280 2281 // See whether biased locking is enabled and if so set it for this 2282 // klass. 2283 // Note that this must be done past the last potential blocking 2284 // point / safepoint. We enable biased locking lazily using a 2285 // VM_Operation to iterate the SystemDictionary and installing the 2286 // biasable mark word into each InstanceKlass's prototype header. 2287 // To avoid race conditions where we accidentally miss enabling the 2288 // optimization for one class in the process of being added to the 2289 // dictionary, we must not safepoint after the test of 2290 // BiasedLocking::enabled(). 2291 if (UseBiasedLocking && BiasedLocking::enabled()) { 2292 // Set biased locking bit for all loaded classes; it will be 2293 // cleared if revocation occurs too often for this type 2294 // NOTE that we must only do this when the class is initally 2295 // defined, not each time it is referenced from a new class loader 2296 if (k->class_loader() == class_loader()) { 2297 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2298 } 2299 } 2300 2301 // Make a new dictionary entry. 2302 Dictionary* dictionary = loader_data->dictionary(); 2303 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2304 if (sd_check == NULL) { 2305 dictionary->add_klass(d_hash, name, k); 2306 notice_modification(); 2307 } 2308 #ifdef ASSERT 2309 sd_check = find_class(d_hash, name, dictionary); 2310 assert (sd_check != NULL, "should have entry in dictionary"); 2311 // Note: there may be a placeholder entry: for circularity testing 2312 // or for parallel defines 2313 #endif 2314 SystemDictionary_lock->notify_all(); 2315 } 2316 } 2317 2318 2319 // Try to find a class name using the loader constraints. The 2320 // loader constraints might know about a class that isn't fully loaded 2321 // yet and these will be ignored. 2322 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2323 Symbol* class_name, Handle class_loader, TRAPS) { 2324 2325 // First see if it has been loaded directly. 2326 // Force the protection domain to be null. (This removes protection checks.) 2327 Handle no_protection_domain; 2328 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2329 no_protection_domain, CHECK_NULL); 2330 if (klass != NULL) 2331 return klass; 2332 2333 // Now look to see if it has been loaded elsewhere, and is subject to 2334 // a loader constraint that would require this loader to return the 2335 // klass that is already loaded. 2336 if (FieldType::is_array(class_name)) { 2337 // For array classes, their Klass*s are not kept in the 2338 // constraint table. The element Klass*s are. 2339 FieldArrayInfo fd; 2340 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2341 if (t != T_OBJECT) { 2342 klass = Universe::typeArrayKlassObj(t); 2343 } else { 2344 MutexLocker mu(SystemDictionary_lock, THREAD); 2345 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2346 } 2347 // If element class already loaded, allocate array klass 2348 if (klass != NULL) { 2349 klass = klass->array_klass_or_null(fd.dimension()); 2350 } 2351 } else { 2352 MutexLocker mu(SystemDictionary_lock, THREAD); 2353 // Non-array classes are easy: simply check the constraint table. 2354 klass = constraints()->find_constrained_klass(class_name, class_loader); 2355 } 2356 2357 return klass; 2358 } 2359 2360 2361 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2362 Handle class_loader1, 2363 Handle class_loader2, 2364 Thread* THREAD) { 2365 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2366 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2367 2368 Symbol* constraint_name = NULL; 2369 if (!FieldType::is_array(class_name)) { 2370 constraint_name = class_name; 2371 } else { 2372 // For array classes, their Klass*s are not kept in the 2373 // constraint table. The element classes are. 2374 FieldArrayInfo fd; 2375 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2376 // primitive types always pass 2377 if (t != T_OBJECT) { 2378 return true; 2379 } else { 2380 constraint_name = fd.object_key(); 2381 } 2382 } 2383 2384 Dictionary* dictionary1 = loader_data1->dictionary(); 2385 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2386 2387 Dictionary* dictionary2 = loader_data2->dictionary(); 2388 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2389 2390 { 2391 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2392 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2393 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2394 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2395 klass2, class_loader2); 2396 } 2397 } 2398 2399 // Add entry to resolution error table to record the error when the first 2400 // attempt to resolve a reference to a class has failed. 2401 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2402 Symbol* error, Symbol* message) { 2403 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2404 int index = resolution_errors()->hash_to_index(hash); 2405 { 2406 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2407 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2408 } 2409 } 2410 2411 // Delete a resolution error for RedefineClasses for a constant pool is going away 2412 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2413 resolution_errors()->delete_entry(pool); 2414 } 2415 2416 // Lookup resolution error table. Returns error if found, otherwise NULL. 2417 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2418 Symbol** message) { 2419 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2420 int index = resolution_errors()->hash_to_index(hash); 2421 { 2422 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2423 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2424 if (entry != NULL) { 2425 *message = entry->message(); 2426 return entry->error(); 2427 } else { 2428 return NULL; 2429 } 2430 } 2431 } 2432 2433 2434 // Signature constraints ensure that callers and callees agree about 2435 // the meaning of type names in their signatures. This routine is the 2436 // intake for constraints. It collects them from several places: 2437 // 2438 // * LinkResolver::resolve_method (if check_access is true) requires 2439 // that the resolving class (the caller) and the defining class of 2440 // the resolved method (the callee) agree on each type in the 2441 // method's signature. 2442 // 2443 // * LinkResolver::resolve_interface_method performs exactly the same 2444 // checks. 2445 // 2446 // * LinkResolver::resolve_field requires that the constant pool 2447 // attempting to link to a field agree with the field's defining 2448 // class about the type of the field signature. 2449 // 2450 // * klassVtable::initialize_vtable requires that, when a class 2451 // overrides a vtable entry allocated by a superclass, that the 2452 // overriding method (i.e., the callee) agree with the superclass 2453 // on each type in the method's signature. 2454 // 2455 // * klassItable::initialize_itable requires that, when a class fills 2456 // in its itables, for each non-abstract method installed in an 2457 // itable, the method (i.e., the callee) agree with the interface 2458 // on each type in the method's signature. 2459 // 2460 // All those methods have a boolean (check_access, checkconstraints) 2461 // which turns off the checks. This is used from specialized contexts 2462 // such as bootstrapping, dumping, and debugging. 2463 // 2464 // No direct constraint is placed between the class and its 2465 // supertypes. Constraints are only placed along linked relations 2466 // between callers and callees. When a method overrides or implements 2467 // an abstract method in a supertype (superclass or interface), the 2468 // constraints are placed as if the supertype were the caller to the 2469 // overriding method. (This works well, since callers to the 2470 // supertype have already established agreement between themselves and 2471 // the supertype.) As a result of all this, a class can disagree with 2472 // its supertype about the meaning of a type name, as long as that 2473 // class neither calls a relevant method of the supertype, nor is 2474 // called (perhaps via an override) from the supertype. 2475 // 2476 // 2477 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2478 // 2479 // Make sure all class components (including arrays) in the given 2480 // signature will be resolved to the same class in both loaders. 2481 // Returns the name of the type that failed a loader constraint check, or 2482 // NULL if no constraint failed. No exception except OOME is thrown. 2483 // Arrays are not added to the loader constraint table, their elements are. 2484 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2485 Handle loader1, Handle loader2, 2486 bool is_method, TRAPS) { 2487 // Nothing to do if loaders are the same. 2488 if (loader1() == loader2()) { 2489 return NULL; 2490 } 2491 2492 SignatureStream sig_strm(signature, is_method); 2493 while (!sig_strm.is_done()) { 2494 if (sig_strm.is_object()) { 2495 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2496 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2497 return sig; 2498 } 2499 } 2500 sig_strm.next(); 2501 } 2502 return NULL; 2503 } 2504 2505 2506 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2507 Symbol* signature, 2508 TRAPS) { 2509 methodHandle empty; 2510 assert(MethodHandles::is_signature_polymorphic(iid) && 2511 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2512 iid != vmIntrinsics::_invokeGeneric, 2513 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2514 2515 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2516 int index = invoke_method_table()->hash_to_index(hash); 2517 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2518 methodHandle m; 2519 if (spe == NULL || spe->method() == NULL) { 2520 spe = NULL; 2521 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2522 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2523 if (!Arguments::is_interpreter_only()) { 2524 // Generate a compiled form of the MH intrinsic. 2525 AdapterHandlerLibrary::create_native_wrapper(m); 2526 // Check if have the compiled code. 2527 if (!m->has_compiled_code()) { 2528 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2529 "Out of space in CodeCache for method handle intrinsic", empty); 2530 } 2531 } 2532 // Now grab the lock. We might have to throw away the new method, 2533 // if a racing thread has managed to install one at the same time. 2534 { 2535 MutexLocker ml(SystemDictionary_lock, THREAD); 2536 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2537 if (spe == NULL) 2538 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2539 if (spe->method() == NULL) 2540 spe->set_method(m()); 2541 } 2542 } 2543 2544 assert(spe != NULL && spe->method() != NULL, ""); 2545 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2546 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2547 "MH intrinsic invariant"); 2548 return spe->method(); 2549 } 2550 2551 // Helper for unpacking the return value from linkMethod and linkCallSite. 2552 static methodHandle unpack_method_and_appendix(Handle mname, 2553 Klass* accessing_klass, 2554 objArrayHandle appendix_box, 2555 Handle* appendix_result, 2556 TRAPS) { 2557 methodHandle empty; 2558 if (mname.not_null()) { 2559 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2560 if (m != NULL) { 2561 oop appendix = appendix_box->obj_at(0); 2562 if (TraceMethodHandles) { 2563 #ifndef PRODUCT 2564 ttyLocker ttyl; 2565 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2566 m->print(); 2567 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2568 tty->cr(); 2569 #endif //PRODUCT 2570 } 2571 (*appendix_result) = Handle(THREAD, appendix); 2572 // the target is stored in the cpCache and if a reference to this 2573 // MethodName is dropped we need a way to make sure the 2574 // class_loader containing this method is kept alive. 2575 // FIXME: the appendix might also preserve this dependency. 2576 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2577 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2578 return methodHandle(THREAD, m); 2579 } 2580 } 2581 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2582 return empty; 2583 } 2584 2585 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2586 Symbol* name, 2587 Symbol* signature, 2588 Klass* accessing_klass, 2589 Handle *appendix_result, 2590 Handle *method_type_result, 2591 TRAPS) { 2592 methodHandle empty; 2593 assert(THREAD->can_call_java() ,""); 2594 Handle method_type = 2595 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2596 2597 int ref_kind = JVM_REF_invokeVirtual; 2598 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2599 Handle name_str (THREAD, name_oop); 2600 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2601 assert(appendix_box->obj_at(0) == NULL, ""); 2602 2603 // This should not happen. JDK code should take care of that. 2604 if (accessing_klass == NULL || method_type.is_null()) { 2605 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2606 } 2607 2608 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2609 JavaCallArguments args; 2610 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2611 args.push_int(ref_kind); 2612 args.push_oop(Handle(THREAD, klass->java_mirror())); 2613 args.push_oop(name_str); 2614 args.push_oop(method_type); 2615 args.push_oop(appendix_box); 2616 JavaValue result(T_OBJECT); 2617 JavaCalls::call_static(&result, 2618 SystemDictionary::MethodHandleNatives_klass(), 2619 vmSymbols::linkMethod_name(), 2620 vmSymbols::linkMethod_signature(), 2621 &args, CHECK_(empty)); 2622 Handle mname(THREAD, (oop) result.get_jobject()); 2623 (*method_type_result) = method_type; 2624 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2625 } 2626 2627 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2628 // We must ensure that all class loaders everywhere will reach this class, for any client. 2629 // This is a safe bet for public classes in java.lang, such as Object and String. 2630 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2631 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2632 static bool is_always_visible_class(oop mirror) { 2633 Klass* klass = java_lang_Class::as_Klass(mirror); 2634 if (klass->is_objArray_klass()) { 2635 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2636 } 2637 if (klass->is_typeArray_klass()) { 2638 return true; // primitive array 2639 } 2640 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2641 return klass->is_public() && 2642 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2643 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2644 } 2645 2646 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2647 // signature, as interpreted relative to the given class loader. 2648 // Because of class loader constraints, all method handle usage must be 2649 // consistent with this loader. 2650 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2651 Klass* accessing_klass, 2652 TRAPS) { 2653 Handle empty; 2654 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2655 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2656 int index = invoke_method_table()->hash_to_index(hash); 2657 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2658 if (spe != NULL && spe->method_type() != NULL) { 2659 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2660 return Handle(THREAD, spe->method_type()); 2661 } else if (!THREAD->can_call_java()) { 2662 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2663 return Handle(); // do not attempt from within compiler, unless it was cached 2664 } 2665 2666 Handle class_loader, protection_domain; 2667 if (accessing_klass != NULL) { 2668 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2669 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2670 } 2671 bool can_be_cached = true; 2672 int npts = ArgumentCount(signature).size(); 2673 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2674 int arg = 0; 2675 Handle rt; // the return type from the signature 2676 ResourceMark rm(THREAD); 2677 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2678 oop mirror = NULL; 2679 if (can_be_cached) { 2680 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2681 mirror = ss.as_java_mirror(Handle(), Handle(), 2682 SignatureStream::ReturnNull, CHECK_(empty)); 2683 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2684 // Fall back to accessing_klass context. 2685 can_be_cached = false; 2686 } 2687 } 2688 if (!can_be_cached) { 2689 // Resolve, throwing a real error if it doesn't work. 2690 mirror = ss.as_java_mirror(class_loader, protection_domain, 2691 SignatureStream::NCDFError, CHECK_(empty)); 2692 } 2693 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string()); 2694 if (ss.at_return_type()) 2695 rt = Handle(THREAD, mirror); 2696 else 2697 pts->obj_at_put(arg++, mirror); 2698 2699 // Check accessibility. 2700 if (ss.is_object() && accessing_klass != NULL) { 2701 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2702 mirror = NULL; // safety 2703 // Emulate ConstantPool::verify_constant_pool_resolve. 2704 if (sel_klass->is_objArray_klass()) 2705 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2706 if (sel_klass->is_instance_klass()) { 2707 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty)); 2708 } 2709 } 2710 } 2711 assert(arg == npts, ""); 2712 2713 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2714 JavaCallArguments args(Handle(THREAD, rt())); 2715 args.push_oop(pts); 2716 JavaValue result(T_OBJECT); 2717 JavaCalls::call_static(&result, 2718 SystemDictionary::MethodHandleNatives_klass(), 2719 vmSymbols::findMethodHandleType_name(), 2720 vmSymbols::findMethodHandleType_signature(), 2721 &args, CHECK_(empty)); 2722 Handle method_type(THREAD, (oop) result.get_jobject()); 2723 2724 if (can_be_cached) { 2725 // We can cache this MethodType inside the JVM. 2726 MutexLocker ml(SystemDictionary_lock, THREAD); 2727 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2728 if (spe == NULL) 2729 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2730 if (spe->method_type() == NULL) { 2731 spe->set_method_type(method_type()); 2732 } 2733 } 2734 2735 // report back to the caller with the MethodType 2736 return method_type; 2737 } 2738 2739 // Ask Java code to find or construct a method handle constant. 2740 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2741 int ref_kind, //e.g., JVM_REF_invokeVirtual 2742 Klass* callee, 2743 Symbol* name_sym, 2744 Symbol* signature, 2745 TRAPS) { 2746 Handle empty; 2747 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2748 Handle type; 2749 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2750 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2751 } else if (caller == NULL) { 2752 // This should not happen. JDK code should take care of that. 2753 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2754 } else { 2755 ResourceMark rm(THREAD); 2756 SignatureStream ss(signature, false); 2757 if (!ss.is_done()) { 2758 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()), 2759 Handle(THREAD, caller->protection_domain()), 2760 SignatureStream::NCDFError, CHECK_(empty)); 2761 type = Handle(THREAD, mirror); 2762 ss.next(); 2763 if (!ss.is_done()) type = Handle(); // error! 2764 } 2765 } 2766 if (type.is_null()) { 2767 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2768 } 2769 2770 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2771 JavaCallArguments args; 2772 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2773 args.push_int(ref_kind); 2774 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2775 args.push_oop(name); 2776 args.push_oop(type); 2777 JavaValue result(T_OBJECT); 2778 JavaCalls::call_static(&result, 2779 SystemDictionary::MethodHandleNatives_klass(), 2780 vmSymbols::linkMethodHandleConstant_name(), 2781 vmSymbols::linkMethodHandleConstant_signature(), 2782 &args, CHECK_(empty)); 2783 return Handle(THREAD, (oop) result.get_jobject()); 2784 } 2785 2786 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2787 // name and signature, as interpreted relative to the given class loader. 2788 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2789 Handle bootstrap_specifier, 2790 Symbol* name, 2791 Symbol* type, 2792 Handle *appendix_result, 2793 Handle *method_type_result, 2794 TRAPS) { 2795 methodHandle empty; 2796 Handle bsm, info; 2797 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2798 bsm = bootstrap_specifier; 2799 } else { 2800 assert(bootstrap_specifier->is_objArray(), ""); 2801 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2802 int len = args->length(); 2803 assert(len >= 1, ""); 2804 bsm = Handle(THREAD, args->obj_at(0)); 2805 if (len > 1) { 2806 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2807 for (int i = 1; i < len; i++) 2808 args1->obj_at_put(i-1, args->obj_at(i)); 2809 info = Handle(THREAD, args1); 2810 } 2811 } 2812 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2813 "caller must supply a valid BSM"); 2814 2815 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2816 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2817 2818 // This should not happen. JDK code should take care of that. 2819 if (caller == NULL || method_type.is_null()) { 2820 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2821 } 2822 2823 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2824 assert(appendix_box->obj_at(0) == NULL, ""); 2825 2826 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2827 JavaCallArguments args; 2828 args.push_oop(Handle(THREAD, caller->java_mirror())); 2829 args.push_oop(bsm); 2830 args.push_oop(method_name); 2831 args.push_oop(method_type); 2832 args.push_oop(info); 2833 args.push_oop(appendix_box); 2834 JavaValue result(T_OBJECT); 2835 JavaCalls::call_static(&result, 2836 SystemDictionary::MethodHandleNatives_klass(), 2837 vmSymbols::linkCallSite_name(), 2838 vmSymbols::linkCallSite_signature(), 2839 &args, CHECK_(empty)); 2840 Handle mname(THREAD, (oop) result.get_jobject()); 2841 (*method_type_result) = method_type; 2842 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2843 } 2844 2845 // Protection domain cache table handling 2846 2847 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2848 return _pd_cache_table->get(protection_domain); 2849 } 2850 2851 void SystemDictionary::reorder_dictionary_for_sharing() { 2852 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); 2853 } 2854 2855 size_t SystemDictionary::count_bytes_for_buckets() { 2856 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); 2857 } 2858 2859 size_t SystemDictionary::count_bytes_for_table() { 2860 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); 2861 } 2862 2863 void SystemDictionary::copy_buckets(char* top, char* end) { 2864 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2865 } 2866 2867 void SystemDictionary::copy_table(char* top, char* end) { 2868 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2869 } 2870 2871 // ---------------------------------------------------------------------------- 2872 void SystemDictionary::print_shared(outputStream *st) { 2873 shared_dictionary()->print_on(st); 2874 } 2875 2876 void SystemDictionary::print_on(outputStream *st) { 2877 if (shared_dictionary() != NULL) { 2878 st->print_cr("Shared Dictionary"); 2879 shared_dictionary()->print_on(st); 2880 st->cr(); 2881 } 2882 2883 GCMutexLocker mu(SystemDictionary_lock); 2884 2885 ClassLoaderDataGraph::print_dictionary(st); 2886 2887 // Placeholders 2888 placeholders()->print_on(st); 2889 st->cr(); 2890 2891 // loader constraints - print under SD_lock 2892 constraints()->print_on(st); 2893 st->cr(); 2894 2895 _pd_cache_table->print_on(st); 2896 st->cr(); 2897 } 2898 2899 void SystemDictionary::verify() { 2900 guarantee(constraints() != NULL, 2901 "Verify of loader constraints failed"); 2902 guarantee(placeholders()->number_of_entries() >= 0, 2903 "Verify of placeholders failed"); 2904 2905 GCMutexLocker mu(SystemDictionary_lock); 2906 2907 // Verify dictionary 2908 ClassLoaderDataGraph::verify_dictionary(); 2909 2910 placeholders()->verify(); 2911 2912 // Verify constraint table 2913 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2914 constraints()->verify(placeholders()); 2915 2916 _pd_cache_table->verify(); 2917 } 2918 2919 void SystemDictionary::dump(outputStream *st, bool verbose) { 2920 assert_locked_or_safepoint(SystemDictionary_lock); 2921 if (verbose) { 2922 print_on(st); 2923 } else { 2924 if (shared_dictionary() != NULL) { 2925 shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); 2926 } 2927 ClassLoaderDataGraph::print_dictionary_statistics(st); 2928 placeholders()->print_table_statistics(st, "Placeholder Table"); 2929 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 2930 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 2931 } 2932 } 2933 2934 // Utility for dumping dictionaries. 2935 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 2936 DCmdWithParser(output, heap), 2937 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 2938 "BOOLEAN", false, "false") { 2939 _dcmdparser.add_dcmd_option(&_verbose); 2940 } 2941 2942 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 2943 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 2944 _verbose.value()); 2945 VMThread::execute(&dumper); 2946 } 2947 2948 int SystemDictionaryDCmd::num_arguments() { 2949 ResourceMark rm; 2950 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 2951 if (dcmd != NULL) { 2952 DCmdMark mark(dcmd); 2953 return dcmd->_dcmdparser.num_arguments(); 2954 } else { 2955 return 0; 2956 } 2957 } 2958 2959 class CombineDictionariesClosure : public CLDClosure { 2960 private: 2961 Dictionary* _master_dictionary; 2962 public: 2963 CombineDictionariesClosure(Dictionary* master_dictionary) : 2964 _master_dictionary(master_dictionary) {} 2965 void do_cld(ClassLoaderData* cld) { 2966 ResourceMark rm; 2967 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 2968 for (int i = 0; i < cld->dictionary()->table_size(); ++i) { 2969 Dictionary* curr_dictionary = cld->dictionary(); 2970 DictionaryEntry* p = curr_dictionary->bucket(i); 2971 while (p != NULL) { 2972 Symbol* name = p->instance_klass()->name(); 2973 unsigned int d_hash = _master_dictionary->compute_hash(name); 2974 int d_index = _master_dictionary->hash_to_index(d_hash); 2975 DictionaryEntry* next = p->next(); 2976 if (p->literal()->class_loader_data() != cld) { 2977 // This is an initiating class loader entry; don't use it 2978 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); 2979 curr_dictionary->free_entry(p); 2980 } else { 2981 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); 2982 curr_dictionary->unlink_entry(p); 2983 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. 2984 _master_dictionary->add_entry(d_index, p); 2985 } 2986 p = next; 2987 } 2988 *curr_dictionary->bucket_addr(i) = NULL; 2989 } 2990 } 2991 } 2992 }; 2993 2994 // Combining platform and system loader dictionaries into boot loader dictionaries. 2995 // During run time, we only have one shared dictionary. 2996 void SystemDictionary::combine_shared_dictionaries() { 2997 assert(DumpSharedSpaces, "dump time only"); 2998 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); 2999 CombineDictionariesClosure cdc(master_dictionary); 3000 ClassLoaderDataGraph::cld_do(&cdc); 3001 3002 // These tables are no longer valid or necessary. Keeping them around will 3003 // cause SystemDictionary::verify() to fail. Let's empty them. 3004 _placeholders = new PlaceholderTable(_placeholder_table_size); 3005 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 3006 3007 NOT_PRODUCT(SystemDictionary::verify()); 3008 } 3009 3010 // caller needs ResourceMark 3011 const char* SystemDictionary::loader_name(const oop loader) { 3012 return ((loader) == NULL ? "<bootloader>" : 3013 InstanceKlass::cast((loader)->klass())->name()->as_C_string()); 3014 } 3015 3016 // caller needs ResourceMark 3017 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { 3018 return (loader_data->class_loader() == NULL ? "<bootloader>" : 3019 SystemDictionary::loader_name(loader_data->class_loader())); 3020 }