1 /* 2 * Copyright (c) 1997, 2016, 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 "classfile/classFileParser.hpp" 27 #include "classfile/classFileStream.hpp" 28 #include "classfile/classLoader.hpp" 29 #include "classfile/classLoaderData.inline.hpp" 30 #include "classfile/classLoaderExt.hpp" 31 #include "classfile/dictionary.hpp" 32 #include "classfile/javaClasses.inline.hpp" 33 #include "classfile/klassFactory.hpp" 34 #include "classfile/loaderConstraints.hpp" 35 #include "classfile/packageEntry.hpp" 36 #include "classfile/placeholders.hpp" 37 #include "classfile/resolutionErrors.hpp" 38 #include "classfile/stringTable.hpp" 39 #include "classfile/systemDictionary.hpp" 40 #include "classfile/vmSymbols.hpp" 41 #include "code/codeCache.hpp" 42 #include "compiler/compileBroker.hpp" 43 #include "gc/shared/gcLocker.hpp" 44 #include "interpreter/bytecodeStream.hpp" 45 #include "interpreter/interpreter.hpp" 46 #include "memory/filemap.hpp" 47 #include "memory/oopFactory.hpp" 48 #include "memory/resourceArea.hpp" 49 #include "oops/instanceKlass.hpp" 50 #include "oops/instanceRefKlass.hpp" 51 #include "oops/klass.inline.hpp" 52 #include "oops/methodData.hpp" 53 #include "oops/objArrayKlass.hpp" 54 #include "oops/objArrayOop.inline.hpp" 55 #include "oops/oop.inline.hpp" 56 #include "oops/symbol.hpp" 57 #include "oops/typeArrayKlass.hpp" 58 #include "prims/jvmtiEnvBase.hpp" 59 #include "prims/methodHandles.hpp" 60 #include "runtime/arguments.hpp" 61 #include "runtime/biasedLocking.hpp" 62 #include "runtime/fieldType.hpp" 63 #include "runtime/handles.inline.hpp" 64 #include "runtime/java.hpp" 65 #include "runtime/javaCalls.hpp" 66 #include "runtime/mutexLocker.hpp" 67 #include "runtime/orderAccess.inline.hpp" 68 #include "runtime/signature.hpp" 69 #include "services/classLoadingService.hpp" 70 #include "services/threadService.hpp" 71 #include "trace/traceMacros.hpp" 72 #include "utilities/macros.hpp" 73 #include "utilities/ticks.hpp" 74 #if INCLUDE_CDS 75 #include "classfile/sharedClassUtil.hpp" 76 #include "classfile/systemDictionaryShared.hpp" 77 #endif 78 #if INCLUDE_JVMCI 79 #include "jvmci/jvmciRuntime.hpp" 80 #endif 81 #if INCLUDE_TRACE 82 #include "trace/tracing.hpp" 83 #endif 84 85 Dictionary* SystemDictionary::_dictionary = NULL; 86 PlaceholderTable* SystemDictionary::_placeholders = NULL; 87 Dictionary* SystemDictionary::_shared_dictionary = NULL; 88 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 89 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 90 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 91 92 93 int SystemDictionary::_number_of_modifications = 0; 94 int SystemDictionary::_sdgeneration = 0; 95 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 96 20201,40423,99991}; 97 98 oop SystemDictionary::_system_loader_lock_obj = NULL; 99 100 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 101 = { NULL /*, NULL...*/ }; 102 103 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 104 105 oop SystemDictionary::_java_system_loader = NULL; 106 107 bool SystemDictionary::_has_loadClassInternal = false; 108 bool SystemDictionary::_has_checkPackageAccess = false; 109 110 // lazily initialized klass variables 111 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 112 113 114 // ---------------------------------------------------------------------------- 115 // Java-level SystemLoader 116 117 oop SystemDictionary::java_system_loader() { 118 return _java_system_loader; 119 } 120 121 void SystemDictionary::compute_java_system_loader(TRAPS) { 122 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 123 JavaValue result(T_OBJECT); 124 JavaCalls::call_static(&result, 125 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 126 vmSymbols::getSystemClassLoader_name(), 127 vmSymbols::void_classloader_signature(), 128 CHECK); 129 130 _java_system_loader = (oop)result.get_jobject(); 131 132 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) 133 } 134 135 136 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 137 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 138 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD); 139 } 140 141 // ---------------------------------------------------------------------------- 142 // Parallel class loading check 143 144 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 145 if (UnsyncloadClass || class_loader.is_null()) return true; 146 if (AlwaysLockClassLoader) return false; 147 return java_lang_ClassLoader::parallelCapable(class_loader()); 148 } 149 // ---------------------------------------------------------------------------- 150 // ParallelDefineClass flag does not apply to bootclass loader 151 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 152 if (class_loader.is_null()) return false; 153 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 154 return true; 155 } 156 return false; 157 } 158 159 // Returns true if the passed class loader is the builtin application class loader 160 // or a custom system class loader. A customer system class loader can be 161 // specified via -Djava.system.class.loader. 162 bool SystemDictionary::is_system_class_loader(Handle class_loader) { 163 if (class_loader.is_null()) { 164 return false; 165 } 166 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 167 class_loader() == _java_system_loader); 168 } 169 170 // Returns true if the passed class loader is the platform class loader. 171 bool SystemDictionary::is_platform_class_loader(Handle class_loader) { 172 if (class_loader.is_null()) { 173 return false; 174 } 175 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 176 } 177 178 // ---------------------------------------------------------------------------- 179 // Resolving of classes 180 181 // Forwards to resolve_or_null 182 183 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 184 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 185 if (HAS_PENDING_EXCEPTION || klass == NULL) { 186 KlassHandle k_h(THREAD, klass); 187 // can return a null klass 188 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD); 189 } 190 return klass; 191 } 192 193 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 194 bool throw_error, 195 KlassHandle klass_h, TRAPS) { 196 if (HAS_PENDING_EXCEPTION) { 197 // If we have a pending exception we forward it to the caller, unless throw_error is true, 198 // in which case we have to check whether the pending exception is a ClassNotFoundException, 199 // and if so convert it to a NoClassDefFoundError 200 // And chain the original ClassNotFoundException 201 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 202 ResourceMark rm(THREAD); 203 assert(klass_h() == NULL, "Should not have result with exception pending"); 204 Handle e(THREAD, PENDING_EXCEPTION); 205 CLEAR_PENDING_EXCEPTION; 206 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 207 } else { 208 return NULL; 209 } 210 } 211 // Class not found, throw appropriate error or exception depending on value of throw_error 212 if (klass_h() == NULL) { 213 ResourceMark rm(THREAD); 214 if (throw_error) { 215 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 216 } else { 217 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 218 } 219 } 220 return (Klass*)klass_h(); 221 } 222 223 224 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 225 bool throw_error, TRAPS) 226 { 227 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 228 } 229 230 231 // Forwards to resolve_instance_class_or_null 232 233 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 234 assert(THREAD->can_call_java(), 235 "can not load classes with compiler thread: class=%s, classloader=%s", 236 class_name->as_C_string(), 237 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 238 if (FieldType::is_array(class_name)) { 239 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 240 } else if (FieldType::is_obj(class_name)) { 241 ResourceMark rm(THREAD); 242 // Ignore wrapping L and ;. 243 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 244 class_name->utf8_length() - 2, CHECK_NULL); 245 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 246 } else { 247 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 248 } 249 } 250 251 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 252 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 253 } 254 255 // Forwards to resolve_instance_class_or_null 256 257 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 258 Handle class_loader, 259 Handle protection_domain, 260 TRAPS) { 261 assert(FieldType::is_array(class_name), "must be array"); 262 Klass* k = NULL; 263 FieldArrayInfo fd; 264 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 265 // of this call 266 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 267 if (t == T_OBJECT) { 268 // naked oop "k" is OK here -- we assign back into it 269 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 270 class_loader, 271 protection_domain, 272 CHECK_NULL); 273 if (k != NULL) { 274 k = k->array_klass(fd.dimension(), CHECK_NULL); 275 } 276 } else { 277 k = Universe::typeArrayKlassObj(t); 278 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 279 } 280 return k; 281 } 282 283 284 // Must be called for any super-class or super-interface resolution 285 // during class definition to allow class circularity checking 286 // super-interface callers: 287 // parse_interfaces - for defineClass & jvmtiRedefineClasses 288 // super-class callers: 289 // ClassFileParser - for defineClass & jvmtiRedefineClasses 290 // load_shared_class - while loading a class from shared archive 291 // resolve_instance_class_or_null: 292 // via: handle_parallel_super_load 293 // when resolving a class that has an existing placeholder with 294 // a saved superclass [i.e. a defineClass is currently in progress] 295 // if another thread is trying to resolve the class, it must do 296 // super-class checks on its own thread to catch class circularity 297 // This last call is critical in class circularity checking for cases 298 // where classloading is delegated to different threads and the 299 // classloader lock is released. 300 // Take the case: Base->Super->Base 301 // 1. If thread T1 tries to do a defineClass of class Base 302 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 303 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 304 // so it tries to load Super 305 // 3. If we load the class internally, or user classloader uses same thread 306 // loadClassFromxxx or defineClass via parseClassFile Super ... 307 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 308 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 309 // 3.4 calls resolve_super_or_fail Base 310 // 3.5 finds T1,Base -> throws class circularity 311 //OR 4. If T2 tries to resolve Super via defineClass Super ... 312 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 313 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 314 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 315 // 4.4 finds T2, Super -> throws class circularity 316 // Must be called, even if superclass is null, since this is 317 // where the placeholder entry is created which claims this 318 // thread is loading this class/classloader. 319 // Be careful when modifying this code: once you have run 320 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 321 // you need to find_and_remove it before returning. 322 // So be careful to not exit with a CHECK_ macro betweeen these calls. 323 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 324 Symbol* class_name, 325 Handle class_loader, 326 Handle protection_domain, 327 bool is_superclass, 328 TRAPS) { 329 #if INCLUDE_CDS 330 if (DumpSharedSpaces) { 331 // Special processing for CDS dump time. 332 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 333 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 334 if (k) { 335 return k; 336 } 337 } 338 #endif // INCLUDE_CDS 339 340 // Double-check, if child class is already loaded, just return super-class,interface 341 // Don't add a placedholder if already loaded, i.e. already in system dictionary 342 // Make sure there's a placeholder for the *child* before resolving. 343 // Used as a claim that this thread is currently loading superclass/classloader 344 // Used here for ClassCircularity checks and also for heap verification 345 // (every InstanceKlass in the heap needs to be in the system dictionary 346 // or have a placeholder). 347 // Must check ClassCircularity before checking if super class is already loaded 348 // 349 // We might not already have a placeholder if this child_name was 350 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 351 // the name of the class might not be known until the stream is actually 352 // parsed. 353 // Bugs 4643874, 4715493 354 // compute_hash can have a safepoint 355 356 ClassLoaderData* loader_data = class_loader_data(class_loader); 357 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 358 int d_index = dictionary()->hash_to_index(d_hash); 359 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 360 int p_index = placeholders()->hash_to_index(p_hash); 361 // can't throw error holding a lock 362 bool child_already_loaded = false; 363 bool throw_circularity_error = false; 364 { 365 MutexLocker mu(SystemDictionary_lock, THREAD); 366 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 367 Klass* quicksuperk; 368 // to support // loading: if child done loading, just return superclass 369 // if class_name, & class_loader don't match: 370 // if initial define, SD update will give LinkageError 371 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 372 // so we don't throw an exception here. 373 // see: nsk redefclass014 & java.lang.instrument Instrument032 374 if ((childk != NULL ) && (is_superclass) && 375 ((quicksuperk = childk->super()) != NULL) && 376 377 ((quicksuperk->name() == class_name) && 378 (quicksuperk->class_loader() == class_loader()))) { 379 return quicksuperk; 380 } else { 381 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 382 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 383 throw_circularity_error = true; 384 } 385 } 386 if (!throw_circularity_error) { 387 // Be careful not to exit resolve_super 388 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 389 } 390 } 391 if (throw_circularity_error) { 392 ResourceMark rm(THREAD); 393 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 394 } 395 396 // java.lang.Object should have been found above 397 assert(class_name != NULL, "null super class for resolving"); 398 // Resolve the super class or interface, check results on return 399 Klass* superk = SystemDictionary::resolve_or_null(class_name, 400 class_loader, 401 protection_domain, 402 THREAD); 403 404 KlassHandle superk_h(THREAD, superk); 405 406 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 407 // It is no longer necessary to keep the placeholder table alive until update_dictionary 408 // or error. GC used to walk the placeholder table as strong roots. 409 // The instanceKlass is kept alive because the class loader is on the stack, 410 // which keeps the loader_data alive, as well as all instanceKlasses in 411 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 412 { 413 MutexLocker mu(SystemDictionary_lock, THREAD); 414 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 415 SystemDictionary_lock->notify_all(); 416 } 417 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 418 // can null superk 419 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD)); 420 } 421 422 return superk_h(); 423 } 424 425 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 426 Handle class_loader, 427 Handle protection_domain, 428 TRAPS) { 429 if(!has_checkPackageAccess()) return; 430 431 // Now we have to call back to java to check if the initating class has access 432 JavaValue result(T_VOID); 433 if (log_is_enabled(Debug, protectiondomain)) { 434 ResourceMark rm; 435 // Print out trace information 436 outputStream* log = Log(protectiondomain)::debug_stream(); 437 log->print_cr("Checking package access"); 438 log->print("class loader: "); class_loader()->print_value_on(log); 439 log->print(" protection domain: "); protection_domain()->print_value_on(log); 440 log->print(" loading: "); klass()->print_value_on(log); 441 log->cr(); 442 } 443 444 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 445 JavaCalls::call_special(&result, 446 class_loader, 447 system_loader, 448 vmSymbols::checkPackageAccess_name(), 449 vmSymbols::class_protectiondomain_signature(), 450 Handle(THREAD, klass->java_mirror()), 451 protection_domain, 452 THREAD); 453 454 if (HAS_PENDING_EXCEPTION) { 455 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 456 } else { 457 log_debug(protectiondomain)("granted"); 458 } 459 460 if (HAS_PENDING_EXCEPTION) return; 461 462 // If no exception has been thrown, we have validated the protection domain 463 // Insert the protection domain of the initiating class into the set. 464 { 465 // We recalculate the entry here -- we've called out to java since 466 // the last time it was calculated. 467 ClassLoaderData* loader_data = class_loader_data(class_loader); 468 469 Symbol* kn = klass->name(); 470 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 471 int d_index = dictionary()->hash_to_index(d_hash); 472 473 MutexLocker mu(SystemDictionary_lock, THREAD); 474 { 475 // Note that we have an entry, and entries can be deleted only during GC, 476 // so we cannot allow GC to occur while we're holding this entry. 477 478 // We're using a NoSafepointVerifier to catch any place where we 479 // might potentially do a GC at all. 480 // Dictionary::do_unloading() asserts that classes in SD are only 481 // unloaded at a safepoint. Anonymous classes are not in SD. 482 NoSafepointVerifier nosafepoint; 483 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 484 protection_domain, THREAD); 485 } 486 } 487 } 488 489 // We only get here if this thread finds that another thread 490 // has already claimed the placeholder token for the current operation, 491 // but that other thread either never owned or gave up the 492 // object lock 493 // Waits on SystemDictionary_lock to indicate placeholder table updated 494 // On return, caller must recheck placeholder table state 495 // 496 // We only get here if 497 // 1) custom classLoader, i.e. not bootstrap classloader 498 // 2) UnsyncloadClass not set 499 // 3) custom classLoader has broken the class loader objectLock 500 // so another thread got here in parallel 501 // 502 // lockObject must be held. 503 // Complicated dance due to lock ordering: 504 // Must first release the classloader object lock to 505 // allow initial definer to complete the class definition 506 // and to avoid deadlock 507 // Reclaim classloader lock object with same original recursion count 508 // Must release SystemDictionary_lock after notify, since 509 // class loader lock must be claimed before SystemDictionary_lock 510 // to prevent deadlocks 511 // 512 // The notify allows applications that did an untimed wait() on 513 // the classloader object lock to not hang. 514 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 515 assert_lock_strong(SystemDictionary_lock); 516 517 bool calledholdinglock 518 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 519 assert(calledholdinglock,"must hold lock for notify"); 520 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 521 ObjectSynchronizer::notifyall(lockObject, THREAD); 522 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 523 SystemDictionary_lock->wait(); 524 SystemDictionary_lock->unlock(); 525 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 526 SystemDictionary_lock->lock(); 527 } 528 529 // If the class in is in the placeholder table, class loading is in progress 530 // For cases where the application changes threads to load classes, it 531 // is critical to ClassCircularity detection that we try loading 532 // the superclass on the same thread internally, so we do parallel 533 // super class loading here. 534 // This also is critical in cases where the original thread gets stalled 535 // even in non-circularity situations. 536 // Note: must call resolve_super_or_fail even if null super - 537 // to force placeholder entry creation for this class for circularity detection 538 // Caller must check for pending exception 539 // Returns non-null Klass* if other thread has completed load 540 // and we are done, 541 // If return null Klass* and no pending exception, the caller must load the class 542 instanceKlassHandle SystemDictionary::handle_parallel_super_load( 543 Symbol* name, Symbol* superclassname, Handle class_loader, 544 Handle protection_domain, Handle lockObject, TRAPS) { 545 546 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 547 ClassLoaderData* loader_data = class_loader_data(class_loader); 548 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 549 int d_index = dictionary()->hash_to_index(d_hash); 550 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 551 int p_index = placeholders()->hash_to_index(p_hash); 552 553 // superk is not used, resolve_super called for circularity check only 554 // This code is reached in two situations. One if this thread 555 // is loading the same class twice (e.g. ClassCircularity, or 556 // java.lang.instrument). 557 // The second is if another thread started the resolve_super first 558 // and has not yet finished. 559 // In both cases the original caller will clean up the placeholder 560 // entry on error. 561 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 562 superclassname, 563 class_loader, 564 protection_domain, 565 true, 566 CHECK_(nh)); 567 568 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 569 // Serial class loaders and bootstrap classloader do wait for superclass loads 570 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 571 MutexLocker mu(SystemDictionary_lock, THREAD); 572 // Check if classloading completed while we were loading superclass or waiting 573 Klass* check = find_class(d_index, d_hash, name, loader_data); 574 if (check != NULL) { 575 // Klass is already loaded, so just return it 576 return(instanceKlassHandle(THREAD, check)); 577 } else { 578 return nh; 579 } 580 } 581 582 // must loop to both handle other placeholder updates 583 // and spurious notifications 584 bool super_load_in_progress = true; 585 PlaceholderEntry* placeholder; 586 while (super_load_in_progress) { 587 MutexLocker mu(SystemDictionary_lock, THREAD); 588 // Check if classloading completed while we were loading superclass or waiting 589 Klass* check = find_class(d_index, d_hash, name, loader_data); 590 if (check != NULL) { 591 // Klass is already loaded, so just return it 592 return(instanceKlassHandle(THREAD, check)); 593 } else { 594 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 595 if (placeholder && placeholder->super_load_in_progress() ){ 596 // Before UnsyncloadClass: 597 // We only get here if the application has released the 598 // classloader lock when another thread was in the middle of loading a 599 // superclass/superinterface for this class, and now 600 // this thread is also trying to load this class. 601 // To minimize surprises, the first thread that started to 602 // load a class should be the one to complete the loading 603 // with the classfile it initially expected. 604 // This logic has the current thread wait once it has done 605 // all the superclass/superinterface loading it can, until 606 // the original thread completes the class loading or fails 607 // If it completes we will use the resulting InstanceKlass 608 // which we will find below in the systemDictionary. 609 // We also get here for parallel bootstrap classloader 610 if (class_loader.is_null()) { 611 SystemDictionary_lock->wait(); 612 } else { 613 double_lock_wait(lockObject, THREAD); 614 } 615 } else { 616 // If not in SD and not in PH, other thread's load must have failed 617 super_load_in_progress = false; 618 } 619 } 620 } 621 return (nh); 622 } 623 624 static void post_class_load_event(const Ticks& start_time, 625 instanceKlassHandle k, 626 const ClassLoaderData* init_cld) { 627 #if INCLUDE_TRACE 628 EventClassLoad event(UNTIMED); 629 if (event.should_commit()) { 630 event.set_starttime(start_time); 631 event.set_loadedClass(k()); 632 event.set_definingClassLoader(k->class_loader_data()); 633 event.set_initiatingClassLoader(init_cld); 634 event.commit(); 635 } 636 #endif // INCLUDE_TRACE 637 } 638 639 static void class_define_event(instanceKlassHandle k, 640 const ClassLoaderData* def_cld) { 641 #if INCLUDE_TRACE 642 EventClassDefine event; 643 if (event.should_commit()) { 644 event.set_definedClass(k()); 645 event.set_definingClassLoader(def_cld); 646 event.commit(); 647 } 648 #endif // INCLUDE_TRACE 649 } 650 651 // Be careful when modifying this code: once you have run 652 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 653 // you need to find_and_remove it before returning. 654 // So be careful to not exit with a CHECK_ macro betweeen these calls. 655 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 656 Handle class_loader, 657 Handle protection_domain, 658 TRAPS) { 659 assert(name != NULL && !FieldType::is_array(name) && 660 !FieldType::is_obj(name), "invalid class name"); 661 662 Ticks class_load_start_time = Ticks::now(); 663 664 // Fix for 4474172; see evaluation for more details 665 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 666 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 667 668 // Do lookup to see if class already exist and the protection domain 669 // has the right access 670 // This call uses find which checks protection domain already matches 671 // All subsequent calls use find_class, and set has_loaded_class so that 672 // before we return a result we call out to java to check for valid protection domain 673 // to allow returning the Klass* and add it to the pd_set if it is valid 674 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 675 int d_index = dictionary()->hash_to_index(d_hash); 676 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 677 protection_domain, THREAD); 678 if (probe != NULL) return probe; 679 680 681 // Non-bootstrap class loaders will call out to class loader and 682 // define via jvm/jni_DefineClass which will acquire the 683 // class loader object lock to protect against multiple threads 684 // defining the class in parallel by accident. 685 // This lock must be acquired here so the waiter will find 686 // any successful result in the SystemDictionary and not attempt 687 // the define 688 // ParallelCapable Classloaders and the bootstrap classloader, 689 // or all classloaders with UnsyncloadClass do not acquire lock here 690 bool DoObjectLock = true; 691 if (is_parallelCapable(class_loader)) { 692 DoObjectLock = false; 693 } 694 695 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 696 int p_index = placeholders()->hash_to_index(p_hash); 697 698 // Class is not in SystemDictionary so we have to do loading. 699 // Make sure we are synchronized on the class loader before we proceed 700 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 701 check_loader_lock_contention(lockObject, THREAD); 702 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 703 704 // Check again (after locking) if class already exist in SystemDictionary 705 bool class_has_been_loaded = false; 706 bool super_load_in_progress = false; 707 bool havesupername = false; 708 instanceKlassHandle k; 709 PlaceholderEntry* placeholder; 710 Symbol* superclassname = NULL; 711 712 { 713 MutexLocker mu(SystemDictionary_lock, THREAD); 714 Klass* check = find_class(d_index, d_hash, name, loader_data); 715 if (check != NULL) { 716 // Klass is already loaded, so just return it 717 class_has_been_loaded = true; 718 k = instanceKlassHandle(THREAD, check); 719 } else { 720 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 721 if (placeholder && placeholder->super_load_in_progress()) { 722 super_load_in_progress = true; 723 if (placeholder->havesupername() == true) { 724 superclassname = placeholder->supername(); 725 havesupername = true; 726 } 727 } 728 } 729 } 730 731 // If the class is in the placeholder table, class loading is in progress 732 if (super_load_in_progress && havesupername==true) { 733 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 734 class_loader, protection_domain, lockObject, THREAD); 735 if (HAS_PENDING_EXCEPTION) { 736 return NULL; 737 } 738 if (!k.is_null()) { 739 class_has_been_loaded = true; 740 } 741 } 742 743 bool throw_circularity_error = false; 744 if (!class_has_been_loaded) { 745 bool load_instance_added = false; 746 747 // add placeholder entry to record loading instance class 748 // Five cases: 749 // All cases need to prevent modifying bootclasssearchpath 750 // in parallel with a classload of same classname 751 // Redefineclasses uses existence of the placeholder for the duration 752 // of the class load to prevent concurrent redefinition of not completely 753 // defined classes. 754 // case 1. traditional classloaders that rely on the classloader object lock 755 // - no other need for LOAD_INSTANCE 756 // case 2. traditional classloaders that break the classloader object lock 757 // as a deadlock workaround. Detection of this case requires that 758 // this check is done while holding the classloader object lock, 759 // and that lock is still held when calling classloader's loadClass. 760 // For these classloaders, we ensure that the first requestor 761 // completes the load and other requestors wait for completion. 762 // case 3. UnsyncloadClass - don't use objectLocker 763 // With this flag, we allow parallel classloading of a 764 // class/classloader pair 765 // case4. Bootstrap classloader - don't own objectLocker 766 // This classloader supports parallelism at the classloader level, 767 // but only allows a single load of a class/classloader pair. 768 // No performance benefit and no deadlock issues. 769 // case 5. parallelCapable user level classloaders - without objectLocker 770 // Allow parallel classloading of a class/classloader pair 771 772 { 773 MutexLocker mu(SystemDictionary_lock, THREAD); 774 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 775 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 776 if (oldprobe) { 777 // only need check_seen_thread once, not on each loop 778 // 6341374 java/lang/Instrument with -Xcomp 779 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 780 throw_circularity_error = true; 781 } else { 782 // case 1: traditional: should never see load_in_progress. 783 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 784 785 // case 4: bootstrap classloader: prevent futile classloading, 786 // wait on first requestor 787 if (class_loader.is_null()) { 788 SystemDictionary_lock->wait(); 789 } else { 790 // case 2: traditional with broken classloader lock. wait on first 791 // requestor. 792 double_lock_wait(lockObject, THREAD); 793 } 794 // Check if classloading completed while we were waiting 795 Klass* check = find_class(d_index, d_hash, name, loader_data); 796 if (check != NULL) { 797 // Klass is already loaded, so just return it 798 k = instanceKlassHandle(THREAD, check); 799 class_has_been_loaded = true; 800 } 801 // check if other thread failed to load and cleaned up 802 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 803 } 804 } 805 } 806 } 807 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 808 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 809 // LOAD_INSTANCE in parallel 810 811 if (!throw_circularity_error && !class_has_been_loaded) { 812 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 813 load_instance_added = true; 814 // For class loaders that do not acquire the classloader object lock, 815 // if they did not catch another thread holding LOAD_INSTANCE, 816 // need a check analogous to the acquire ObjectLocker/find_class 817 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 818 // one final check if the load has already completed 819 // class loaders holding the ObjectLock shouldn't find the class here 820 Klass* check = find_class(d_index, d_hash, name, loader_data); 821 if (check != NULL) { 822 // Klass is already loaded, so return it after checking/adding protection domain 823 k = instanceKlassHandle(THREAD, check); 824 class_has_been_loaded = true; 825 } 826 } 827 } 828 829 // must throw error outside of owning lock 830 if (throw_circularity_error) { 831 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 832 ResourceMark rm(THREAD); 833 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 834 } 835 836 if (!class_has_been_loaded) { 837 838 // Do actual loading 839 k = load_instance_class(name, class_loader, THREAD); 840 841 // For UnsyncloadClass only 842 // If they got a linkageError, check if a parallel class load succeeded. 843 // If it did, then for bytecode resolution the specification requires 844 // that we return the same result we did for the other thread, i.e. the 845 // successfully loaded InstanceKlass 846 // Should not get here for classloaders that support parallelism 847 // with the new cleaner mechanism, even with AllowParallelDefineClass 848 // Bootstrap goes through here to allow for an extra guarantee check 849 if (UnsyncloadClass || (class_loader.is_null())) { 850 if (k.is_null() && HAS_PENDING_EXCEPTION 851 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 852 MutexLocker mu(SystemDictionary_lock, THREAD); 853 Klass* check = find_class(d_index, d_hash, name, loader_data); 854 if (check != NULL) { 855 // Klass is already loaded, so just use it 856 k = instanceKlassHandle(THREAD, check); 857 CLEAR_PENDING_EXCEPTION; 858 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 859 } 860 } 861 } 862 863 // If everything was OK (no exceptions, no null return value), and 864 // class_loader is NOT the defining loader, do a little more bookkeeping. 865 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 866 k->class_loader() != class_loader()) { 867 868 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 869 870 // Need to check for a PENDING_EXCEPTION again; check_constraints 871 // can throw and doesn't use the CHECK macro. 872 if (!HAS_PENDING_EXCEPTION) { 873 { // Grabbing the Compile_lock prevents systemDictionary updates 874 // during compilations. 875 MutexLocker mu(Compile_lock, THREAD); 876 update_dictionary(d_index, d_hash, p_index, p_hash, 877 k, class_loader, THREAD); 878 } 879 880 if (JvmtiExport::should_post_class_load()) { 881 Thread *thread = THREAD; 882 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 883 JvmtiExport::post_class_load((JavaThread *) thread, k()); 884 } 885 } 886 } 887 } // load_instance_class loop 888 889 if (load_instance_added == true) { 890 // clean up placeholder entries for LOAD_INSTANCE success or error 891 // This brackets the SystemDictionary updates for both defining 892 // and initiating loaders 893 MutexLocker mu(SystemDictionary_lock, THREAD); 894 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 895 SystemDictionary_lock->notify_all(); 896 } 897 } 898 899 if (HAS_PENDING_EXCEPTION || k.is_null()) { 900 return NULL; 901 } 902 903 post_class_load_event(class_load_start_time, k, loader_data); 904 905 #ifdef ASSERT 906 { 907 ClassLoaderData* loader_data = k->class_loader_data(); 908 MutexLocker mu(SystemDictionary_lock, THREAD); 909 Klass* kk = find_class(name, loader_data); 910 assert(kk == k(), "should be present in dictionary"); 911 } 912 #endif 913 914 // return if the protection domain in NULL 915 if (protection_domain() == NULL) return k(); 916 917 // Check the protection domain has the right access 918 { 919 MutexLocker mu(SystemDictionary_lock, THREAD); 920 // Note that we have an entry, and entries can be deleted only during GC, 921 // so we cannot allow GC to occur while we're holding this entry. 922 // We're using a NoSafepointVerifier to catch any place where we 923 // might potentially do a GC at all. 924 // Dictionary::do_unloading() asserts that classes in SD are only 925 // unloaded at a safepoint. Anonymous classes are not in SD. 926 NoSafepointVerifier nosafepoint; 927 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 928 loader_data, 929 protection_domain)) { 930 return k(); 931 } 932 } 933 934 // Verify protection domain. If it fails an exception is thrown 935 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 936 937 return k(); 938 } 939 940 941 // This routine does not lock the system dictionary. 942 // 943 // Since readers don't hold a lock, we must make sure that system 944 // dictionary entries are only removed at a safepoint (when only one 945 // thread is running), and are added to in a safe way (all links must 946 // be updated in an MT-safe manner). 947 // 948 // Callers should be aware that an entry could be added just after 949 // _dictionary->bucket(index) is read here, so the caller will not see 950 // the new entry. 951 952 Klass* SystemDictionary::find(Symbol* class_name, 953 Handle class_loader, 954 Handle protection_domain, 955 TRAPS) { 956 957 // The result of this call should be consistent with the result 958 // of the call to resolve_instance_class_or_null(). 959 // See evaluation 6790209 and 4474172 for more details. 960 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 961 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 962 963 if (loader_data == NULL) { 964 // If the ClassLoaderData has not been setup, 965 // then the class loader has no entries in the dictionary. 966 return NULL; 967 } 968 969 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 970 int d_index = dictionary()->hash_to_index(d_hash); 971 972 { 973 // Note that we have an entry, and entries can be deleted only during GC, 974 // so we cannot allow GC to occur while we're holding this entry. 975 // We're using a NoSafepointVerifier to catch any place where we 976 // might potentially do a GC at all. 977 // Dictionary::do_unloading() asserts that classes in SD are only 978 // unloaded at a safepoint. Anonymous classes are not in SD. 979 NoSafepointVerifier nosafepoint; 980 return dictionary()->find(d_index, d_hash, class_name, loader_data, 981 protection_domain, THREAD); 982 } 983 } 984 985 986 // Look for a loaded instance or array klass by name. Do not do any loading. 987 // return NULL in case of error. 988 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 989 Handle class_loader, 990 Handle protection_domain, 991 TRAPS) { 992 Klass* k = NULL; 993 assert(class_name != NULL, "class name must be non NULL"); 994 995 if (FieldType::is_array(class_name)) { 996 // The name refers to an array. Parse the name. 997 // dimension and object_key in FieldArrayInfo are assigned as a 998 // side-effect of this call 999 FieldArrayInfo fd; 1000 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 1001 if (t != T_OBJECT) { 1002 k = Universe::typeArrayKlassObj(t); 1003 } else { 1004 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 1005 } 1006 if (k != NULL) { 1007 k = k->array_klass_or_null(fd.dimension()); 1008 } 1009 } else { 1010 k = find(class_name, class_loader, protection_domain, THREAD); 1011 } 1012 return k; 1013 } 1014 1015 // Note: this method is much like resolve_from_stream, but 1016 // does not publish the classes via the SystemDictionary. 1017 // Handles unsafe_DefineAnonymousClass and redefineclasses 1018 // RedefinedClasses do not add to the class hierarchy 1019 Klass* SystemDictionary::parse_stream(Symbol* class_name, 1020 Handle class_loader, 1021 Handle protection_domain, 1022 ClassFileStream* st, 1023 const InstanceKlass* host_klass, 1024 GrowableArray<Handle>* cp_patches, 1025 TRAPS) { 1026 1027 Ticks class_load_start_time = Ticks::now(); 1028 1029 ClassLoaderData* loader_data; 1030 if (host_klass != NULL) { 1031 // Create a new CLD for anonymous class, that uses the same class loader 1032 // as the host_klass 1033 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 1034 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping"); 1035 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 1036 loader_data->record_dependency(host_klass, CHECK_NULL); 1037 } else { 1038 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1039 } 1040 1041 assert(st != NULL, "invariant"); 1042 assert(st->need_verify(), "invariant"); 1043 1044 // Parse stream and create a klass. 1045 // Note that we do this even though this klass might 1046 // already be present in the SystemDictionary, otherwise we would not 1047 // throw potential ClassFormatErrors. 1048 1049 instanceKlassHandle k = KlassFactory::create_from_stream(st, 1050 class_name, 1051 loader_data, 1052 protection_domain, 1053 host_klass, 1054 cp_patches, 1055 CHECK_NULL); 1056 1057 if (host_klass != NULL && k.not_null()) { 1058 // If it's anonymous, initialize it now, since nobody else will. 1059 1060 { 1061 MutexLocker mu_r(Compile_lock, THREAD); 1062 1063 // Add to class hierarchy, initialize vtables, and do possible 1064 // deoptimizations. 1065 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1066 1067 // But, do not add to system dictionary. 1068 1069 // compiled code dependencies need to be validated anyway 1070 notice_modification(); 1071 } 1072 1073 // Rewrite and patch constant pool here. 1074 k->link_class(CHECK_NULL); 1075 if (cp_patches != NULL) { 1076 k->constants()->patch_resolved_references(cp_patches); 1077 } 1078 k->eager_initialize(CHECK_NULL); 1079 1080 // notify jvmti 1081 if (JvmtiExport::should_post_class_load()) { 1082 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1083 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1084 } 1085 1086 post_class_load_event(class_load_start_time, k, loader_data); 1087 } 1088 assert(host_klass != NULL || NULL == cp_patches, 1089 "cp_patches only found with host_klass"); 1090 1091 return k(); 1092 } 1093 1094 // Add a klass to the system from a stream (called by jni_DefineClass and 1095 // JVM_DefineClass). 1096 // Note: class_name can be NULL. In that case we do not know the name of 1097 // the class until we have parsed the stream. 1098 1099 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1100 Handle class_loader, 1101 Handle protection_domain, 1102 ClassFileStream* st, 1103 TRAPS) { 1104 1105 // Classloaders that support parallelism, e.g. bootstrap classloader, 1106 // or all classloaders with UnsyncloadClass do not acquire lock here 1107 bool DoObjectLock = true; 1108 if (is_parallelCapable(class_loader)) { 1109 DoObjectLock = false; 1110 } 1111 1112 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1113 1114 // Make sure we are synchronized on the class loader before we proceed 1115 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1116 check_loader_lock_contention(lockObject, THREAD); 1117 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1118 1119 assert(st != NULL, "invariant"); 1120 1121 // Parse the stream and create a klass. 1122 // Note that we do this even though this klass might 1123 // already be present in the SystemDictionary, otherwise we would not 1124 // throw potential ClassFormatErrors. 1125 // 1126 1127 instanceKlassHandle k; 1128 1129 #if INCLUDE_CDS 1130 k = SystemDictionaryShared::lookup_from_stream(class_name, 1131 class_loader, 1132 protection_domain, 1133 st, 1134 CHECK_NULL); 1135 #endif 1136 1137 if (k.is_null()) { 1138 if (st->buffer() == NULL) { 1139 return NULL; 1140 } 1141 k = KlassFactory::create_from_stream(st, 1142 class_name, 1143 loader_data, 1144 protection_domain, 1145 NULL, // host_klass 1146 NULL, // cp_patches 1147 CHECK_NULL); 1148 } 1149 1150 assert(k.not_null(), "no klass created"); 1151 Symbol* h_name = k->name(); 1152 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1153 1154 // Add class just loaded 1155 // If a class loader supports parallel classloading handle parallel define requests 1156 // find_or_define_instance_class may return a different InstanceKlass 1157 if (is_parallelCapable(class_loader)) { 1158 k = find_or_define_instance_class(h_name, class_loader, k, CHECK_NULL); 1159 } else { 1160 define_instance_class(k, CHECK_NULL); 1161 } 1162 1163 // Make sure we have an entry in the SystemDictionary on success 1164 debug_only( { 1165 MutexLocker mu(SystemDictionary_lock, THREAD); 1166 1167 Klass* check = find_class(h_name, k->class_loader_data()); 1168 assert(check == k(), "should be present in the dictionary"); 1169 } ); 1170 1171 return k(); 1172 } 1173 1174 #if INCLUDE_CDS 1175 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1176 int number_of_entries) { 1177 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1178 "bad shared dictionary size."); 1179 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1180 } 1181 1182 1183 // If there is a shared dictionary, then find the entry for the 1184 // given shared system class, if any. 1185 1186 Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1187 if (shared_dictionary() != NULL) { 1188 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1189 int d_index = shared_dictionary()->hash_to_index(d_hash); 1190 1191 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1192 } else { 1193 return NULL; 1194 } 1195 } 1196 1197 1198 // Load a class from the shared spaces (found through the shared system 1199 // dictionary). Force the superclass and all interfaces to be loaded. 1200 // Update the class definition to include sibling classes and no 1201 // subclasses (yet). [Classes in the shared space are not part of the 1202 // object hierarchy until loaded.] 1203 1204 instanceKlassHandle SystemDictionary::load_shared_class( 1205 Symbol* class_name, Handle class_loader, TRAPS) { 1206 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1207 // Make sure we only return the boot class for the NULL classloader. 1208 if (ik.not_null() && 1209 ik->is_shared_boot_class() && class_loader.is_null()) { 1210 Handle protection_domain; 1211 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1212 } 1213 return instanceKlassHandle(); 1214 } 1215 1216 // Check if a shared class can be loaded by the specific classloader: 1217 // 1218 // NULL classloader: 1219 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1220 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1221 // be defined in an unnamed module. 1222 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1223 instanceKlassHandle ik, 1224 Handle class_loader, TRAPS) { 1225 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1226 "Cannot use sharing if java.base is patched"); 1227 ResourceMark rm; 1228 int path_index = ik->shared_classpath_index(); 1229 SharedClassPathEntry* ent = 1230 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index); 1231 if (!Universe::is_module_initialized()) { 1232 assert(ent != NULL && ent->is_jrt(), 1233 "Loading non-bootstrap classes before the module system is initialized"); 1234 assert(class_loader.is_null(), "sanity"); 1235 return true; 1236 } 1237 // Get the pkg_entry from the classloader 1238 TempNewSymbol pkg_name = NULL; 1239 PackageEntry* pkg_entry = NULL; 1240 ModuleEntry* mod_entry = NULL; 1241 const char* pkg_string = NULL; 1242 ClassLoaderData* loader_data = class_loader_data(class_loader); 1243 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1244 if (pkg_name != NULL) { 1245 pkg_string = pkg_name->as_C_string(); 1246 if (loader_data != NULL) { 1247 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1248 } 1249 if (pkg_entry != NULL) { 1250 mod_entry = pkg_entry->module(); 1251 } 1252 } 1253 1254 // If the archived class is from a module that has been patched at runtime, 1255 // the class cannot be loaded from the archive. 1256 if (mod_entry != NULL && mod_entry->is_patched()) { 1257 return false; 1258 } 1259 1260 if (class_loader.is_null()) { 1261 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1262 // The NULL classloader can load archived class originated from the 1263 // "modules" jimage and the -Xbootclasspath/a. For class from the 1264 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1265 // by the NULL classloader. 1266 if (mod_entry != NULL) { 1267 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1268 // ModuleEntry's location agrees with the archived class' origination. 1269 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) { 1270 return true; // Module class from the "module" jimage 1271 } 1272 } 1273 1274 // If the archived class is not from the "module" jimage, the class can be 1275 // loaded by the NULL classloader if 1276 // 1277 // 1. the class is from the unamed package 1278 // 2. or, the class is not from a module defined in the NULL classloader 1279 // 3. or, the class is from an unamed module 1280 if (!ent->is_jrt() && ik->is_shared_boot_class()) { 1281 // the class is from the -Xbootclasspath/a 1282 if (pkg_string == NULL || 1283 pkg_entry == NULL || 1284 pkg_entry->in_unnamed_module()) { 1285 assert(mod_entry == NULL || 1286 mod_entry == loader_data->modules()->unnamed_module(), 1287 "the unnamed module is not defined in the classloader"); 1288 return true; 1289 } 1290 } 1291 return false; 1292 } else { 1293 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1294 ik, class_loader, pkg_string, pkg_name, 1295 pkg_entry, mod_entry, CHECK_(false)); 1296 return res; 1297 } 1298 } 1299 1300 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik, 1301 Handle class_loader, 1302 Handle protection_domain, TRAPS) { 1303 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1304 1305 if (ik.not_null()) { 1306 Symbol* class_name = ik->name(); 1307 1308 bool visible = is_shared_class_visible( 1309 class_name, ik, class_loader, CHECK_(nh)); 1310 if (!visible) { 1311 return nh; 1312 } 1313 1314 // Resolve the superclass and interfaces. They must be the same 1315 // as in dump time, because the layout of <ik> depends on 1316 // the specific layout of ik->super() and ik->local_interfaces(). 1317 // 1318 // If unexpected superclass or interfaces are found, we cannot 1319 // load <ik> from the shared archive. 1320 1321 if (ik->super() != NULL) { 1322 Symbol* cn = ik->super()->name(); 1323 Klass *s = resolve_super_or_fail(class_name, cn, 1324 class_loader, protection_domain, true, CHECK_(nh)); 1325 if (s != ik->super()) { 1326 // The dynamically resolved super class is not the same as the one we used during dump time, 1327 // so we cannot use ik. 1328 return nh; 1329 } else { 1330 assert(s->is_shared(), "must be"); 1331 } 1332 } 1333 1334 Array<Klass*>* interfaces = ik->local_interfaces(); 1335 int num_interfaces = interfaces->length(); 1336 for (int index = 0; index < num_interfaces; index++) { 1337 Klass* k = interfaces->at(index); 1338 1339 // Note: can not use InstanceKlass::cast here because 1340 // interfaces' InstanceKlass's C++ vtbls haven't been 1341 // reinitialized yet (they will be once the interface classes 1342 // are loaded) 1343 Symbol* name = k->name(); 1344 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh)); 1345 if (k != i) { 1346 // The dynamically resolved interface class is not the same as the one we used during dump time, 1347 // so we cannot use ik. 1348 return nh; 1349 } else { 1350 assert(i->is_shared(), "must be"); 1351 } 1352 } 1353 1354 instanceKlassHandle new_ik = KlassFactory::check_shared_class_file_load_hook( 1355 ik, class_name, class_loader, protection_domain, CHECK_(nh)); 1356 if (new_ik.not_null()) { 1357 // The class is changed by CFLH. Return the new class. The shared class is 1358 // not used. 1359 return new_ik; 1360 } 1361 1362 // Adjust methods to recover missing data. They need addresses for 1363 // interpreter entry points and their default native method address 1364 // must be reset. 1365 1366 // Updating methods must be done under a lock so multiple 1367 // threads don't update these in parallel 1368 // 1369 // Shared classes are all currently loaded by either the bootstrap or 1370 // internal parallel class loaders, so this will never cause a deadlock 1371 // on a custom class loader lock. 1372 1373 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1374 { 1375 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1376 check_loader_lock_contention(lockObject, THREAD); 1377 ObjectLocker ol(lockObject, THREAD, true); 1378 // prohibited package check assumes all classes loaded from archive call 1379 // restore_unshareable_info which calls ik->set_package() 1380 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh)); 1381 } 1382 1383 if (log_is_enabled(Info, class, load)) { 1384 ik()->print_loading_log(LogLevel::Info, loader_data, NULL, NULL); 1385 } 1386 // No 'else' here as logging levels are not mutually exclusive 1387 1388 if (log_is_enabled(Debug, class, load)) { 1389 ik()->print_loading_log(LogLevel::Debug, loader_data, NULL, NULL); 1390 } 1391 1392 // For boot loader, ensure that GetSystemPackage knows that a class in this 1393 // package was loaded. 1394 if (class_loader.is_null()) { 1395 int path_index = ik->shared_classpath_index(); 1396 ResourceMark rm; 1397 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1398 } 1399 1400 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1401 // Only dump the classes that can be stored into CDS archive 1402 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1403 ResourceMark rm(THREAD); 1404 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1405 classlist_file->flush(); 1406 } 1407 } 1408 1409 // notify a class loaded from shared object 1410 ClassLoadingService::notify_class_loaded(ik(), true /* shared class */); 1411 } 1412 return ik; 1413 } 1414 #endif // INCLUDE_CDS 1415 1416 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1417 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1418 1419 if (class_loader.is_null()) { 1420 ResourceMark rm; 1421 PackageEntry* pkg_entry = NULL; 1422 bool search_only_bootloader_append = false; 1423 ClassLoaderData *loader_data = class_loader_data(class_loader); 1424 1425 // Find the package in the boot loader's package entry table. 1426 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1427 if (pkg_name != NULL) { 1428 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1429 } 1430 1431 // Prior to attempting to load the class, enforce the boot loader's 1432 // visibility boundaries. 1433 if (!Universe::is_module_initialized()) { 1434 // During bootstrapping, prior to module initialization, any 1435 // class attempting to be loaded must be checked against the 1436 // java.base packages in the boot loader's PackageEntryTable. 1437 // No class outside of java.base is allowed to be loaded during 1438 // this bootstrapping window. 1439 if (!DumpSharedSpaces) { 1440 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1441 // Class is either in the unnamed package or in 1442 // a named package within the unnamed module. Either 1443 // case is outside of java.base, do not attempt to 1444 // load the class post java.base definition. If 1445 // java.base has not been defined, let the class load 1446 // and its package will be checked later by 1447 // ModuleEntryTable::verify_javabase_packages. 1448 if (ModuleEntryTable::javabase_defined()) { 1449 return nh; 1450 } 1451 } else { 1452 // Check that the class' package is defined within java.base. 1453 ModuleEntry* mod_entry = pkg_entry->module(); 1454 Symbol* mod_entry_name = mod_entry->name(); 1455 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1456 return nh; 1457 } 1458 } 1459 } 1460 } else { 1461 assert(!DumpSharedSpaces, "Archive dumped after module system initialization"); 1462 // After the module system has been initialized, check if the class' 1463 // package is in a module defined to the boot loader. 1464 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1465 // Class is either in the unnamed package, in a named package 1466 // within a module not defined to the boot loader or in a 1467 // a named package within the unnamed module. In all cases, 1468 // limit visibility to search for the class only in the boot 1469 // loader's append path. 1470 search_only_bootloader_append = true; 1471 } 1472 } 1473 1474 // Prior to bootstrapping's module initialization, never load a class outside 1475 // of the boot loader's module path 1476 assert(Universe::is_module_initialized() || DumpSharedSpaces || 1477 !search_only_bootloader_append, 1478 "Attempt to load a class outside of boot loader's module path"); 1479 1480 // Search the shared system dictionary for classes preloaded into the 1481 // shared spaces. 1482 instanceKlassHandle k; 1483 { 1484 #if INCLUDE_CDS 1485 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1486 k = load_shared_class(class_name, class_loader, THREAD); 1487 #endif 1488 } 1489 1490 if (k.is_null()) { 1491 // Use VM class loader 1492 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1493 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_(nh)); 1494 } 1495 1496 // find_or_define_instance_class may return a different InstanceKlass 1497 if (!k.is_null()) { 1498 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1499 } 1500 return k; 1501 } else { 1502 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1503 ResourceMark rm(THREAD); 1504 1505 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1506 JavaThread* jt = (JavaThread*) THREAD; 1507 1508 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1509 ClassLoader::perf_app_classload_selftime(), 1510 ClassLoader::perf_app_classload_count(), 1511 jt->get_thread_stat()->perf_recursion_counts_addr(), 1512 jt->get_thread_stat()->perf_timers_addr(), 1513 PerfClassTraceTime::CLASS_LOAD); 1514 1515 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1516 // Translate to external class name format, i.e., convert '/' chars to '.' 1517 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1518 1519 JavaValue result(T_OBJECT); 1520 1521 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1522 1523 // Call public unsynchronized loadClass(String) directly for all class loaders 1524 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1525 // acquire a class-name based lock rather than the class loader object lock. 1526 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1527 // so the call to loadClassInternal() was not required. 1528 // 1529 // UnsyncloadClass flag means both call loadClass(String) and do 1530 // not acquire the class loader lock even for class loaders that are 1531 // not parallelCapable. This was a risky transitional 1532 // flag for diagnostic purposes only. It is risky to call 1533 // custom class loaders without synchronization. 1534 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1535 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1536 // Do NOT assume this will be supported in future releases. 1537 // 1538 // Added MustCallLoadClassInternal in case we discover in the field 1539 // a customer that counts on this call 1540 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1541 JavaCalls::call_special(&result, 1542 class_loader, 1543 spec_klass, 1544 vmSymbols::loadClassInternal_name(), 1545 vmSymbols::string_class_signature(), 1546 string, 1547 CHECK_(nh)); 1548 } else { 1549 JavaCalls::call_virtual(&result, 1550 class_loader, 1551 spec_klass, 1552 vmSymbols::loadClass_name(), 1553 vmSymbols::string_class_signature(), 1554 string, 1555 CHECK_(nh)); 1556 } 1557 1558 assert(result.get_type() == T_OBJECT, "just checking"); 1559 oop obj = (oop) result.get_jobject(); 1560 1561 // Primitive classes return null since forName() can not be 1562 // used to obtain any of the Class objects representing primitives or void 1563 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1564 instanceKlassHandle k = 1565 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1566 // For user defined Java class loaders, check that the name returned is 1567 // the same as that requested. This check is done for the bootstrap 1568 // loader when parsing the class file. 1569 if (class_name == k->name()) { 1570 return k; 1571 } 1572 } 1573 // Class is not found or has the wrong name, return NULL 1574 return nh; 1575 } 1576 } 1577 1578 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1579 1580 ClassLoaderData* loader_data = k->class_loader_data(); 1581 Handle class_loader_h(THREAD, loader_data->class_loader()); 1582 1583 // for bootstrap and other parallel classloaders don't acquire lock, 1584 // use placeholder token 1585 // If a parallelCapable class loader calls define_instance_class instead of 1586 // find_or_define_instance_class to get here, we have a timing 1587 // hole with systemDictionary updates and check_constraints 1588 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1589 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1590 compute_loader_lock_object(class_loader_h, THREAD)), 1591 "define called without lock"); 1592 } 1593 1594 // Check class-loading constraints. Throw exception if violation is detected. 1595 // Grabs and releases SystemDictionary_lock 1596 // The check_constraints/find_class call and update_dictionary sequence 1597 // must be "atomic" for a specific class/classloader pair so we never 1598 // define two different instanceKlasses for that class/classloader pair. 1599 // Existing classloaders will call define_instance_class with the 1600 // classloader lock held 1601 // Parallel classloaders will call find_or_define_instance_class 1602 // which will require a token to perform the define class 1603 Symbol* name_h = k->name(); 1604 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1605 int d_index = dictionary()->hash_to_index(d_hash); 1606 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1607 1608 // Register class just loaded with class loader (placed in Vector) 1609 // Note we do this before updating the dictionary, as this can 1610 // fail with an OutOfMemoryError (if it does, we will *not* put this 1611 // class in the dictionary and will not update the class hierarchy). 1612 // JVMTI FollowReferences needs to find the classes this way. 1613 if (k->class_loader() != NULL) { 1614 methodHandle m(THREAD, Universe::loader_addClass_method()); 1615 JavaValue result(T_VOID); 1616 JavaCallArguments args(class_loader_h); 1617 args.push_oop(Handle(THREAD, k->java_mirror())); 1618 JavaCalls::call(&result, m, &args, CHECK); 1619 } 1620 1621 // Add the new class. We need recompile lock during update of CHA. 1622 { 1623 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1624 int p_index = placeholders()->hash_to_index(p_hash); 1625 1626 MutexLocker mu_r(Compile_lock, THREAD); 1627 1628 // Add to class hierarchy, initialize vtables, and do possible 1629 // deoptimizations. 1630 add_to_hierarchy(k, CHECK); // No exception, but can block 1631 1632 // Add to systemDictionary - so other classes can see it. 1633 // Grabs and releases SystemDictionary_lock 1634 update_dictionary(d_index, d_hash, p_index, p_hash, 1635 k, class_loader_h, THREAD); 1636 } 1637 k->eager_initialize(THREAD); 1638 1639 // notify jvmti 1640 if (JvmtiExport::should_post_class_load()) { 1641 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1642 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1643 1644 } 1645 class_define_event(k, loader_data); 1646 } 1647 1648 // Support parallel classloading 1649 // All parallel class loaders, including bootstrap classloader 1650 // lock a placeholder entry for this class/class_loader pair 1651 // to allow parallel defines of different classes for this class loader 1652 // With AllowParallelDefine flag==true, in case they do not synchronize around 1653 // FindLoadedClass/DefineClass, calls, we check for parallel 1654 // loading for them, wait if a defineClass is in progress 1655 // and return the initial requestor's results 1656 // This flag does not apply to the bootstrap classloader. 1657 // With AllowParallelDefine flag==false, call through to define_instance_class 1658 // which will throw LinkageError: duplicate class definition. 1659 // False is the requested default. 1660 // For better performance, the class loaders should synchronize 1661 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1662 // potentially waste time reading and parsing the bytestream. 1663 // Note: VM callers should ensure consistency of k/class_name,class_loader 1664 // Be careful when modifying this code: once you have run 1665 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1666 // you need to find_and_remove it before returning. 1667 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1668 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1669 1670 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1671 Symbol* name_h = k->name(); // passed in class_name may be null 1672 ClassLoaderData* loader_data = class_loader_data(class_loader); 1673 1674 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1675 int d_index = dictionary()->hash_to_index(d_hash); 1676 1677 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1678 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1679 int p_index = placeholders()->hash_to_index(p_hash); 1680 PlaceholderEntry* probe; 1681 1682 { 1683 MutexLocker mu(SystemDictionary_lock, THREAD); 1684 // First check if class already defined 1685 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1686 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1687 if (check != NULL) { 1688 return(instanceKlassHandle(THREAD, check)); 1689 } 1690 } 1691 1692 // Acquire define token for this class/classloader 1693 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1694 // Wait if another thread defining in parallel 1695 // All threads wait - even those that will throw duplicate class: otherwise 1696 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1697 // if other thread has not finished updating dictionary 1698 while (probe->definer() != NULL) { 1699 SystemDictionary_lock->wait(); 1700 } 1701 // Only special cases allow parallel defines and can use other thread's results 1702 // Other cases fall through, and may run into duplicate defines 1703 // caught by finding an entry in the SystemDictionary 1704 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1705 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1706 SystemDictionary_lock->notify_all(); 1707 #ifdef ASSERT 1708 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1709 assert(check != NULL, "definer missed recording success"); 1710 #endif 1711 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1712 } else { 1713 // This thread will define the class (even if earlier thread tried and had an error) 1714 probe->set_definer(THREAD); 1715 } 1716 } 1717 1718 define_instance_class(k, THREAD); 1719 1720 Handle linkage_exception = Handle(); // null handle 1721 1722 // definer must notify any waiting threads 1723 { 1724 MutexLocker mu(SystemDictionary_lock, THREAD); 1725 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1726 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1727 if (probe != NULL) { 1728 if (HAS_PENDING_EXCEPTION) { 1729 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1730 CLEAR_PENDING_EXCEPTION; 1731 } else { 1732 probe->set_instance_klass(k()); 1733 } 1734 probe->set_definer(NULL); 1735 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1736 SystemDictionary_lock->notify_all(); 1737 } 1738 } 1739 1740 // Can't throw exception while holding lock due to rank ordering 1741 if (linkage_exception() != NULL) { 1742 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1743 } 1744 1745 return k; 1746 } 1747 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1748 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1749 if (class_loader.is_null()) { 1750 return Handle(THREAD, _system_loader_lock_obj); 1751 } else { 1752 return class_loader; 1753 } 1754 } 1755 1756 // This method is added to check how often we have to wait to grab loader 1757 // lock. The results are being recorded in the performance counters defined in 1758 // ClassLoader::_sync_systemLoaderLockContentionRate and 1759 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1760 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1761 if (!UsePerfData) { 1762 return; 1763 } 1764 1765 assert(!loader_lock.is_null(), "NULL lock object"); 1766 1767 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1768 == ObjectSynchronizer::owner_other) { 1769 // contention will likely happen, so increment the corresponding 1770 // contention counter. 1771 if (loader_lock() == _system_loader_lock_obj) { 1772 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1773 } else { 1774 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1775 } 1776 } 1777 } 1778 1779 // ---------------------------------------------------------------------------- 1780 // Lookup 1781 1782 Klass* SystemDictionary::find_class(int index, unsigned int hash, 1783 Symbol* class_name, 1784 ClassLoaderData* loader_data) { 1785 assert_locked_or_safepoint(SystemDictionary_lock); 1786 assert (index == dictionary()->index_for(class_name, loader_data), 1787 "incorrect index?"); 1788 1789 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1790 return k; 1791 } 1792 1793 1794 // Basic find on classes in the midst of being loaded 1795 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1796 ClassLoaderData* loader_data) { 1797 assert_locked_or_safepoint(SystemDictionary_lock); 1798 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1799 int p_index = placeholders()->hash_to_index(p_hash); 1800 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1801 } 1802 1803 1804 // Used for assertions and verification only 1805 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1806 #ifndef ASSERT 1807 guarantee(VerifyBeforeGC || 1808 VerifyDuringGC || 1809 VerifyBeforeExit || 1810 VerifyDuringStartup || 1811 VerifyAfterGC, "too expensive"); 1812 #endif 1813 assert_locked_or_safepoint(SystemDictionary_lock); 1814 1815 // First look in the loaded class array 1816 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1817 int d_index = dictionary()->hash_to_index(d_hash); 1818 return find_class(d_index, d_hash, class_name, loader_data); 1819 } 1820 1821 1822 // Get the next class in the dictionary. 1823 Klass* SystemDictionary::try_get_next_class() { 1824 return dictionary()->try_get_next_class(); 1825 } 1826 1827 1828 // ---------------------------------------------------------------------------- 1829 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1830 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1831 // before a new class is used. 1832 1833 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1834 assert(k.not_null(), "just checking"); 1835 assert_locked_or_safepoint(Compile_lock); 1836 1837 // Link into hierachy. Make sure the vtables are initialized before linking into 1838 k->append_to_sibling_list(); // add to superklass/sibling list 1839 k->process_interfaces(THREAD); // handle all "implements" declarations 1840 k->set_init_state(InstanceKlass::loaded); 1841 // Now flush all code that depended on old class hierarchy. 1842 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1843 // Also, first reinitialize vtable because it may have gotten out of synch 1844 // while the new class wasn't connected to the class hierarchy. 1845 CodeCache::flush_dependents_on(k); 1846 } 1847 1848 // ---------------------------------------------------------------------------- 1849 // GC support 1850 1851 // Following roots during mark-sweep is separated in two phases. 1852 // 1853 // The first phase follows preloaded classes and all other system 1854 // classes, since these will never get unloaded anyway. 1855 // 1856 // The second phase removes (unloads) unreachable classes from the 1857 // system dictionary and follows the remaining classes' contents. 1858 1859 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1860 roots_oops_do(blk, NULL); 1861 } 1862 1863 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1864 // Follow all system classes and temporary placeholders in dictionary 1865 dictionary()->always_strong_classes_do(closure); 1866 1867 // Placeholders. These represent classes we're actively loading. 1868 placeholders()->classes_do(closure); 1869 } 1870 1871 // Calculate a "good" systemdictionary size based 1872 // on predicted or current loaded classes count 1873 int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1874 int newsize = _old_default_sdsize; 1875 if ((classcount > 0) && !DumpSharedSpaces) { 1876 int desiredsize = classcount/_average_depth_goal; 1877 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1878 newsize = _primelist[++_sdgeneration]) { 1879 if (desiredsize <= newsize) { 1880 break; 1881 } 1882 } 1883 } 1884 return newsize; 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 system dictionary 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 bool clean_previous_versions) { 1909 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1910 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, 1911 clean_previous_versions); 1912 if (unloading_occurred) { 1913 dictionary()->do_unloading(); 1914 constraints()->purge_loader_constraints(); 1915 resolution_errors()->purge_resolution_errors(); 1916 } 1917 // Oops referenced by the system dictionary may get unreachable independently 1918 // of the class loader (eg. cached protection domain oops). So we need to 1919 // explicitly unlink them here instead of in Dictionary::do_unloading. 1920 dictionary()->unlink(is_alive); 1921 #ifdef ASSERT 1922 VerifySDReachableAndLiveClosure cl(is_alive); 1923 dictionary()->oops_do(&cl); 1924 #endif 1925 return unloading_occurred; 1926 } 1927 1928 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1929 strong->do_oop(&_java_system_loader); 1930 strong->do_oop(&_system_loader_lock_obj); 1931 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) 1932 1933 // Adjust dictionary 1934 dictionary()->roots_oops_do(strong, weak); 1935 1936 // Visit extra methods 1937 invoke_method_table()->oops_do(strong); 1938 } 1939 1940 void SystemDictionary::oops_do(OopClosure* f) { 1941 f->do_oop(&_java_system_loader); 1942 f->do_oop(&_system_loader_lock_obj); 1943 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1944 1945 // Adjust dictionary 1946 dictionary()->oops_do(f); 1947 1948 // Visit extra methods 1949 invoke_method_table()->oops_do(f); 1950 } 1951 1952 // Extended Class redefinition support. 1953 // If one of these classes is replaced, we need to replace it in these places. 1954 // KlassClosure::do_klass should take the address of a class but we can 1955 // change that later. 1956 void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 1957 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 1958 f->do_klass(_well_known_klasses[k]); 1959 } 1960 1961 { 1962 for (int i = 0; i < T_VOID+1; i++) { 1963 if (_box_klasses[i] != NULL) { 1964 assert(i >= T_BOOLEAN, "checking"); 1965 f->do_klass(_box_klasses[i]); 1966 } 1967 } 1968 } 1969 1970 FilteredFieldsMap::classes_do(f); 1971 } 1972 1973 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 1974 f->do_klass(_abstract_ownable_synchronizer_klass); 1975 } 1976 1977 // Just the classes from defining class loaders 1978 // Don't iterate over placeholders 1979 void SystemDictionary::classes_do(void f(Klass*)) { 1980 dictionary()->classes_do(f); 1981 } 1982 1983 // Added for initialize_itable_for_klass 1984 // Just the classes from defining class loaders 1985 // Don't iterate over placeholders 1986 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 1987 dictionary()->classes_do(f, CHECK); 1988 } 1989 1990 // All classes, and their class loaders 1991 // Don't iterate over placeholders 1992 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 1993 dictionary()->classes_do(f); 1994 } 1995 1996 void SystemDictionary::placeholders_do(void f(Symbol*)) { 1997 placeholders()->entries_do(f); 1998 } 1999 2000 void SystemDictionary::methods_do(void f(Method*)) { 2001 dictionary()->methods_do(f); 2002 invoke_method_table()->methods_do(f); 2003 } 2004 2005 void SystemDictionary::remove_classes_in_error_state() { 2006 dictionary()->remove_classes_in_error_state(); 2007 } 2008 2009 // ---------------------------------------------------------------------------- 2010 // Lazily load klasses 2011 2012 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 2013 // if multiple threads calling this function, only one thread will load 2014 // the class. The other threads will find the loaded version once the 2015 // class is loaded. 2016 Klass* aos = _abstract_ownable_synchronizer_klass; 2017 if (aos == NULL) { 2018 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 2019 // Force a fence to prevent any read before the write completes 2020 OrderAccess::fence(); 2021 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); 2022 } 2023 } 2024 2025 // ---------------------------------------------------------------------------- 2026 // Initialization 2027 2028 void SystemDictionary::initialize(TRAPS) { 2029 // Allocate arrays 2030 assert(dictionary() == NULL, 2031 "SystemDictionary should only be initialized once"); 2032 _sdgeneration = 0; 2033 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 2034 _placeholders = new PlaceholderTable(_nof_buckets); 2035 _number_of_modifications = 0; 2036 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 2037 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 2038 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 2039 2040 // Allocate private object used as system class loader lock 2041 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 2042 // Initialize basic classes 2043 initialize_preloaded_classes(CHECK); 2044 } 2045 2046 // Compact table of directions on the initialization of klasses: 2047 static const short wk_init_info[] = { 2048 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 2049 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 2050 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 2051 | (int)SystemDictionary::option ), 2052 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 2053 #undef WK_KLASS_INIT_INFO 2054 0 2055 }; 2056 2057 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 2058 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2059 int info = wk_init_info[id - FIRST_WKID]; 2060 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2061 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 2062 InstanceKlass** klassp = &_well_known_klasses[id]; 2063 2064 bool must_load; 2065 #if INCLUDE_JVMCI 2066 if (EnableJVMCI) { 2067 // If JVMCI is enabled we require its classes to be found. 2068 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 2069 } else 2070 #endif 2071 { 2072 must_load = (init_opt < SystemDictionary::Opt); 2073 } 2074 2075 if ((*klassp) == NULL) { 2076 Klass* k; 2077 if (must_load) { 2078 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 2079 } else { 2080 k = resolve_or_null(symbol, CHECK_0); // load optional klass 2081 } 2082 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 2083 } 2084 return ((*klassp) != NULL); 2085 } 2086 2087 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 2088 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 2089 for (int id = (int)start_id; id < (int)limit_id; id++) { 2090 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2091 int info = wk_init_info[id - FIRST_WKID]; 2092 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2093 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 2094 2095 initialize_wk_klass((WKID)id, opt, CHECK); 2096 } 2097 2098 // move the starting value forward to the limit: 2099 start_id = limit_id; 2100 } 2101 2102 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 2103 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 2104 2105 // Create the ModuleEntry for java.base. This call needs to be done here, 2106 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 2107 ClassLoader::classLoader_init2(CHECK); 2108 2109 // Preload commonly used klasses 2110 WKID scan = FIRST_WKID; 2111 // first do Object, then String, Class 2112 if (UseSharedSpaces) { 2113 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2114 // Initialize the constant pool for the Object_class 2115 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 2116 ik->constants()->restore_unshareable_info(CHECK); 2117 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2118 } else { 2119 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2120 } 2121 2122 // Calculate offsets for String and Class classes since they are loaded and 2123 // can be used after this point. 2124 java_lang_String::compute_offsets(); 2125 java_lang_Class::compute_offsets(); 2126 2127 // Fixup mirrors for classes loaded before java.lang.Class. 2128 // These calls iterate over the objects currently in the perm gen 2129 // so calling them at this point is matters (not before when there 2130 // are fewer objects and not later after there are more objects 2131 // in the perm gen. 2132 Universe::initialize_basic_type_mirrors(CHECK); 2133 Universe::fixup_mirrors(CHECK); 2134 2135 // do a bunch more: 2136 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2137 2138 // Preload ref klasses and set reference types 2139 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2140 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2141 2142 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2143 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2144 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2145 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2146 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2147 2148 // JSR 292 classes 2149 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2150 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2151 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 2152 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 2153 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); 2154 2155 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2156 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2157 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2158 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2159 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2160 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2161 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2162 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2163 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2164 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2165 2166 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 2167 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 2168 _has_loadClassInternal = (method != NULL); 2169 } 2170 { // Compute whether we should use checkPackageAccess or NOT 2171 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2172 _has_checkPackageAccess = (method != NULL); 2173 } 2174 } 2175 2176 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2177 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2178 BasicType SystemDictionary::box_klass_type(Klass* k) { 2179 assert(k != NULL, ""); 2180 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2181 if (_box_klasses[i] == k) 2182 return (BasicType)i; 2183 } 2184 return T_OBJECT; 2185 } 2186 2187 // Constraints on class loaders. The details of the algorithm can be 2188 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2189 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2190 // that the system dictionary needs to maintain a set of contraints that 2191 // must be satisfied by all classes in the dictionary. 2192 // if defining is true, then LinkageError if already in systemDictionary 2193 // if initiating loader, then ok if InstanceKlass matches existing entry 2194 2195 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 2196 instanceKlassHandle k, 2197 Handle class_loader, bool defining, 2198 TRAPS) { 2199 const char *linkage_error1 = NULL; 2200 const char *linkage_error2 = NULL; 2201 { 2202 Symbol* name = k->name(); 2203 ClassLoaderData *loader_data = class_loader_data(class_loader); 2204 2205 MutexLocker mu(SystemDictionary_lock, THREAD); 2206 2207 Klass* check = find_class(d_index, d_hash, name, loader_data); 2208 if (check != (Klass*)NULL) { 2209 // if different InstanceKlass - duplicate class definition, 2210 // else - ok, class loaded by a different thread in parallel, 2211 // we should only have found it if it was done loading and ok to use 2212 // system dictionary only holds instance classes, placeholders 2213 // also holds array classes 2214 2215 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2216 if ((defining == true) || (k() != check)) { 2217 linkage_error1 = "loader (instance of "; 2218 linkage_error2 = "): attempted duplicate class definition for name: \""; 2219 } else { 2220 return; 2221 } 2222 } 2223 2224 #ifdef ASSERT 2225 Symbol* ph_check = find_placeholder(name, loader_data); 2226 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2227 #endif 2228 2229 if (linkage_error1 == NULL) { 2230 if (constraints()->check_or_update(k, class_loader, name) == false) { 2231 linkage_error1 = "loader constraint violation: loader (instance of "; 2232 linkage_error2 = ") previously initiated loading for a different type with name \""; 2233 } 2234 } 2235 } 2236 2237 // Throw error now if needed (cannot throw while holding 2238 // SystemDictionary_lock because of rank ordering) 2239 2240 if (linkage_error1) { 2241 ResourceMark rm(THREAD); 2242 const char* class_loader_name = loader_name(class_loader()); 2243 char* type_name = k->name()->as_C_string(); 2244 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) + 2245 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte. 2246 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2247 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name); 2248 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2249 } 2250 } 2251 2252 2253 // Update system dictionary - done after check_constraint and add_to_hierachy 2254 // have been called. 2255 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 2256 int p_index, unsigned int p_hash, 2257 instanceKlassHandle k, 2258 Handle class_loader, 2259 TRAPS) { 2260 // Compile_lock prevents systemDictionary updates during compilations 2261 assert_locked_or_safepoint(Compile_lock); 2262 Symbol* name = k->name(); 2263 ClassLoaderData *loader_data = class_loader_data(class_loader); 2264 2265 { 2266 MutexLocker mu1(SystemDictionary_lock, THREAD); 2267 2268 // See whether biased locking is enabled and if so set it for this 2269 // klass. 2270 // Note that this must be done past the last potential blocking 2271 // point / safepoint. We enable biased locking lazily using a 2272 // VM_Operation to iterate the SystemDictionary and installing the 2273 // biasable mark word into each InstanceKlass's prototype header. 2274 // To avoid race conditions where we accidentally miss enabling the 2275 // optimization for one class in the process of being added to the 2276 // dictionary, we must not safepoint after the test of 2277 // BiasedLocking::enabled(). 2278 if (UseBiasedLocking && BiasedLocking::enabled()) { 2279 // Set biased locking bit for all loaded classes; it will be 2280 // cleared if revocation occurs too often for this type 2281 // NOTE that we must only do this when the class is initally 2282 // defined, not each time it is referenced from a new class loader 2283 if (k->class_loader() == class_loader()) { 2284 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2285 } 2286 } 2287 2288 // Make a new system dictionary entry. 2289 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2290 if (sd_check == NULL) { 2291 dictionary()->add_klass(name, loader_data, k); 2292 notice_modification(); 2293 } 2294 #ifdef ASSERT 2295 sd_check = find_class(d_index, d_hash, name, loader_data); 2296 assert (sd_check != NULL, "should have entry in system dictionary"); 2297 // Note: there may be a placeholder entry: for circularity testing 2298 // or for parallel defines 2299 #endif 2300 SystemDictionary_lock->notify_all(); 2301 } 2302 } 2303 2304 2305 // Try to find a class name using the loader constraints. The 2306 // loader constraints might know about a class that isn't fully loaded 2307 // yet and these will be ignored. 2308 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2309 Symbol* class_name, Handle class_loader, TRAPS) { 2310 2311 // First see if it has been loaded directly. 2312 // Force the protection domain to be null. (This removes protection checks.) 2313 Handle no_protection_domain; 2314 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2315 no_protection_domain, CHECK_NULL); 2316 if (klass != NULL) 2317 return klass; 2318 2319 // Now look to see if it has been loaded elsewhere, and is subject to 2320 // a loader constraint that would require this loader to return the 2321 // klass that is already loaded. 2322 if (FieldType::is_array(class_name)) { 2323 // For array classes, their Klass*s are not kept in the 2324 // constraint table. The element Klass*s are. 2325 FieldArrayInfo fd; 2326 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2327 if (t != T_OBJECT) { 2328 klass = Universe::typeArrayKlassObj(t); 2329 } else { 2330 MutexLocker mu(SystemDictionary_lock, THREAD); 2331 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2332 } 2333 // If element class already loaded, allocate array klass 2334 if (klass != NULL) { 2335 klass = klass->array_klass_or_null(fd.dimension()); 2336 } 2337 } else { 2338 MutexLocker mu(SystemDictionary_lock, THREAD); 2339 // Non-array classes are easy: simply check the constraint table. 2340 klass = constraints()->find_constrained_klass(class_name, class_loader); 2341 } 2342 2343 return klass; 2344 } 2345 2346 2347 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2348 Handle class_loader1, 2349 Handle class_loader2, 2350 Thread* THREAD) { 2351 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2352 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2353 2354 Symbol* constraint_name = NULL; 2355 if (!FieldType::is_array(class_name)) { 2356 constraint_name = class_name; 2357 } else { 2358 // For array classes, their Klass*s are not kept in the 2359 // constraint table. The element classes are. 2360 FieldArrayInfo fd; 2361 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2362 // primitive types always pass 2363 if (t != T_OBJECT) { 2364 return true; 2365 } else { 2366 constraint_name = fd.object_key(); 2367 } 2368 } 2369 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2370 int d_index1 = dictionary()->hash_to_index(d_hash1); 2371 2372 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2373 int d_index2 = dictionary()->hash_to_index(d_hash2); 2374 { 2375 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2376 2377 // Better never do a GC while we're holding these oops 2378 NoSafepointVerifier nosafepoint; 2379 2380 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2381 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2382 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2383 klass2, class_loader2); 2384 } 2385 } 2386 2387 // Add entry to resolution error table to record the error when the first 2388 // attempt to resolve a reference to a class has failed. 2389 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2390 Symbol* error, Symbol* message) { 2391 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2392 int index = resolution_errors()->hash_to_index(hash); 2393 { 2394 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2395 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2396 } 2397 } 2398 2399 // Delete a resolution error for RedefineClasses for a constant pool is going away 2400 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2401 resolution_errors()->delete_entry(pool); 2402 } 2403 2404 // Lookup resolution error table. Returns error if found, otherwise NULL. 2405 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2406 Symbol** message) { 2407 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2408 int index = resolution_errors()->hash_to_index(hash); 2409 { 2410 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2411 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2412 if (entry != NULL) { 2413 *message = entry->message(); 2414 return entry->error(); 2415 } else { 2416 return NULL; 2417 } 2418 } 2419 } 2420 2421 2422 // Signature constraints ensure that callers and callees agree about 2423 // the meaning of type names in their signatures. This routine is the 2424 // intake for constraints. It collects them from several places: 2425 // 2426 // * LinkResolver::resolve_method (if check_access is true) requires 2427 // that the resolving class (the caller) and the defining class of 2428 // the resolved method (the callee) agree on each type in the 2429 // method's signature. 2430 // 2431 // * LinkResolver::resolve_interface_method performs exactly the same 2432 // checks. 2433 // 2434 // * LinkResolver::resolve_field requires that the constant pool 2435 // attempting to link to a field agree with the field's defining 2436 // class about the type of the field signature. 2437 // 2438 // * klassVtable::initialize_vtable requires that, when a class 2439 // overrides a vtable entry allocated by a superclass, that the 2440 // overriding method (i.e., the callee) agree with the superclass 2441 // on each type in the method's signature. 2442 // 2443 // * klassItable::initialize_itable requires that, when a class fills 2444 // in its itables, for each non-abstract method installed in an 2445 // itable, the method (i.e., the callee) agree with the interface 2446 // on each type in the method's signature. 2447 // 2448 // All those methods have a boolean (check_access, checkconstraints) 2449 // which turns off the checks. This is used from specialized contexts 2450 // such as bootstrapping, dumping, and debugging. 2451 // 2452 // No direct constraint is placed between the class and its 2453 // supertypes. Constraints are only placed along linked relations 2454 // between callers and callees. When a method overrides or implements 2455 // an abstract method in a supertype (superclass or interface), the 2456 // constraints are placed as if the supertype were the caller to the 2457 // overriding method. (This works well, since callers to the 2458 // supertype have already established agreement between themselves and 2459 // the supertype.) As a result of all this, a class can disagree with 2460 // its supertype about the meaning of a type name, as long as that 2461 // class neither calls a relevant method of the supertype, nor is 2462 // called (perhaps via an override) from the supertype. 2463 // 2464 // 2465 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2466 // 2467 // Make sure all class components (including arrays) in the given 2468 // signature will be resolved to the same class in both loaders. 2469 // Returns the name of the type that failed a loader constraint check, or 2470 // NULL if no constraint failed. No exception except OOME is thrown. 2471 // Arrays are not added to the loader constraint table, their elements are. 2472 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2473 Handle loader1, Handle loader2, 2474 bool is_method, TRAPS) { 2475 // Nothing to do if loaders are the same. 2476 if (loader1() == loader2()) { 2477 return NULL; 2478 } 2479 2480 SignatureStream sig_strm(signature, is_method); 2481 while (!sig_strm.is_done()) { 2482 if (sig_strm.is_object()) { 2483 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2484 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2485 return sig; 2486 } 2487 } 2488 sig_strm.next(); 2489 } 2490 return NULL; 2491 } 2492 2493 2494 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2495 Symbol* signature, 2496 TRAPS) { 2497 methodHandle empty; 2498 assert(MethodHandles::is_signature_polymorphic(iid) && 2499 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2500 iid != vmIntrinsics::_invokeGeneric, 2501 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2502 2503 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2504 int index = invoke_method_table()->hash_to_index(hash); 2505 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2506 methodHandle m; 2507 if (spe == NULL || spe->method() == NULL) { 2508 spe = NULL; 2509 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2510 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2511 if (!Arguments::is_interpreter_only()) { 2512 // Generate a compiled form of the MH intrinsic. 2513 AdapterHandlerLibrary::create_native_wrapper(m); 2514 // Check if have the compiled code. 2515 if (!m->has_compiled_code()) { 2516 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2517 "Out of space in CodeCache for method handle intrinsic", empty); 2518 } 2519 } 2520 // Now grab the lock. We might have to throw away the new method, 2521 // if a racing thread has managed to install one at the same time. 2522 { 2523 MutexLocker ml(SystemDictionary_lock, THREAD); 2524 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2525 if (spe == NULL) 2526 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2527 if (spe->method() == NULL) 2528 spe->set_method(m()); 2529 } 2530 } 2531 2532 assert(spe != NULL && spe->method() != NULL, ""); 2533 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2534 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2535 "MH intrinsic invariant"); 2536 return spe->method(); 2537 } 2538 2539 // Helper for unpacking the return value from linkMethod and linkCallSite. 2540 static methodHandle unpack_method_and_appendix(Handle mname, 2541 KlassHandle accessing_klass, 2542 objArrayHandle appendix_box, 2543 Handle* appendix_result, 2544 TRAPS) { 2545 methodHandle empty; 2546 if (mname.not_null()) { 2547 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2548 if (vmtarget != NULL && vmtarget->is_method()) { 2549 Method* m = (Method*)vmtarget; 2550 oop appendix = appendix_box->obj_at(0); 2551 if (TraceMethodHandles) { 2552 #ifndef PRODUCT 2553 ttyLocker ttyl; 2554 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2555 m->print(); 2556 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2557 tty->cr(); 2558 #endif //PRODUCT 2559 } 2560 (*appendix_result) = Handle(THREAD, appendix); 2561 // the target is stored in the cpCache and if a reference to this 2562 // MethodName is dropped we need a way to make sure the 2563 // class_loader containing this method is kept alive. 2564 // FIXME: the appendix might also preserve this dependency. 2565 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2566 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2567 return methodHandle(THREAD, m); 2568 } 2569 } 2570 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2571 return empty; 2572 } 2573 2574 methodHandle SystemDictionary::find_method_handle_invoker(KlassHandle klass, 2575 Symbol* name, 2576 Symbol* signature, 2577 KlassHandle accessing_klass, 2578 Handle *appendix_result, 2579 Handle *method_type_result, 2580 TRAPS) { 2581 methodHandle empty; 2582 assert(THREAD->can_call_java() ,""); 2583 Handle method_type = 2584 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2585 2586 int ref_kind = JVM_REF_invokeVirtual; 2587 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2588 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2589 assert(appendix_box->obj_at(0) == NULL, ""); 2590 2591 // This should not happen. JDK code should take care of that. 2592 if (accessing_klass.is_null() || method_type.is_null()) { 2593 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2594 } 2595 2596 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2597 JavaCallArguments args; 2598 args.push_oop(accessing_klass()->java_mirror()); 2599 args.push_int(ref_kind); 2600 args.push_oop(klass()->java_mirror()); 2601 args.push_oop(name_str()); 2602 args.push_oop(method_type()); 2603 args.push_oop(appendix_box()); 2604 JavaValue result(T_OBJECT); 2605 JavaCalls::call_static(&result, 2606 SystemDictionary::MethodHandleNatives_klass(), 2607 vmSymbols::linkMethod_name(), 2608 vmSymbols::linkMethod_signature(), 2609 &args, CHECK_(empty)); 2610 Handle mname(THREAD, (oop) result.get_jobject()); 2611 (*method_type_result) = method_type; 2612 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2613 } 2614 2615 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2616 // We must ensure that all class loaders everywhere will reach this class, for any client. 2617 // This is a safe bet for public classes in java.lang, such as Object and String. 2618 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2619 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2620 static bool is_always_visible_class(oop mirror) { 2621 Klass* klass = java_lang_Class::as_Klass(mirror); 2622 if (klass->is_objArray_klass()) { 2623 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2624 } 2625 if (klass->is_typeArray_klass()) { 2626 return true; // primitive array 2627 } 2628 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2629 return klass->is_public() && 2630 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2631 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2632 } 2633 2634 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2635 // signature, as interpreted relative to the given class loader. 2636 // Because of class loader constraints, all method handle usage must be 2637 // consistent with this loader. 2638 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2639 KlassHandle accessing_klass, 2640 TRAPS) { 2641 Handle empty; 2642 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2643 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2644 int index = invoke_method_table()->hash_to_index(hash); 2645 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2646 if (spe != NULL && spe->method_type() != NULL) { 2647 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2648 return Handle(THREAD, spe->method_type()); 2649 } else if (!THREAD->can_call_java()) { 2650 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2651 return Handle(); // do not attempt from within compiler, unless it was cached 2652 } 2653 2654 Handle class_loader, protection_domain; 2655 if (accessing_klass.not_null()) { 2656 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2657 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2658 } 2659 bool can_be_cached = true; 2660 int npts = ArgumentCount(signature).size(); 2661 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2662 int arg = 0; 2663 Handle rt; // the return type from the signature 2664 ResourceMark rm(THREAD); 2665 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2666 oop mirror = NULL; 2667 if (can_be_cached) { 2668 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2669 mirror = ss.as_java_mirror(Handle(), Handle(), 2670 SignatureStream::ReturnNull, CHECK_(empty)); 2671 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2672 // Fall back to accessing_klass context. 2673 can_be_cached = false; 2674 } 2675 } 2676 if (!can_be_cached) { 2677 // Resolve, throwing a real error if it doesn't work. 2678 mirror = ss.as_java_mirror(class_loader, protection_domain, 2679 SignatureStream::NCDFError, CHECK_(empty)); 2680 } 2681 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string()); 2682 if (ss.at_return_type()) 2683 rt = Handle(THREAD, mirror); 2684 else 2685 pts->obj_at_put(arg++, mirror); 2686 2687 // Check accessibility. 2688 if (ss.is_object() && accessing_klass.not_null()) { 2689 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2690 mirror = NULL; // safety 2691 // Emulate ConstantPool::verify_constant_pool_resolve. 2692 if (sel_klass->is_objArray_klass()) 2693 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2694 if (sel_klass->is_instance_klass()) { 2695 KlassHandle sel_kh(THREAD, sel_klass); 2696 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2697 } 2698 } 2699 } 2700 assert(arg == npts, ""); 2701 2702 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2703 JavaCallArguments args(Handle(THREAD, rt())); 2704 args.push_oop(pts()); 2705 JavaValue result(T_OBJECT); 2706 JavaCalls::call_static(&result, 2707 SystemDictionary::MethodHandleNatives_klass(), 2708 vmSymbols::findMethodHandleType_name(), 2709 vmSymbols::findMethodHandleType_signature(), 2710 &args, CHECK_(empty)); 2711 Handle method_type(THREAD, (oop) result.get_jobject()); 2712 2713 if (can_be_cached) { 2714 // We can cache this MethodType inside the JVM. 2715 MutexLocker ml(SystemDictionary_lock, THREAD); 2716 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2717 if (spe == NULL) 2718 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2719 if (spe->method_type() == NULL) { 2720 spe->set_method_type(method_type()); 2721 } 2722 } 2723 2724 // report back to the caller with the MethodType 2725 return method_type; 2726 } 2727 2728 // Ask Java code to find or construct a method handle constant. 2729 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2730 int ref_kind, //e.g., JVM_REF_invokeVirtual 2731 KlassHandle callee, 2732 Symbol* name_sym, 2733 Symbol* signature, 2734 TRAPS) { 2735 Handle empty; 2736 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2737 Handle type; 2738 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2739 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2740 } else if (caller.is_null()) { 2741 // This should not happen. JDK code should take care of that. 2742 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2743 } else { 2744 ResourceMark rm(THREAD); 2745 SignatureStream ss(signature, false); 2746 if (!ss.is_done()) { 2747 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2748 SignatureStream::NCDFError, CHECK_(empty)); 2749 type = Handle(THREAD, mirror); 2750 ss.next(); 2751 if (!ss.is_done()) type = Handle(); // error! 2752 } 2753 } 2754 if (type.is_null()) { 2755 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2756 } 2757 2758 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2759 JavaCallArguments args; 2760 args.push_oop(caller->java_mirror()); // the referring class 2761 args.push_int(ref_kind); 2762 args.push_oop(callee->java_mirror()); // the target class 2763 args.push_oop(name()); 2764 args.push_oop(type()); 2765 JavaValue result(T_OBJECT); 2766 JavaCalls::call_static(&result, 2767 SystemDictionary::MethodHandleNatives_klass(), 2768 vmSymbols::linkMethodHandleConstant_name(), 2769 vmSymbols::linkMethodHandleConstant_signature(), 2770 &args, CHECK_(empty)); 2771 return Handle(THREAD, (oop) result.get_jobject()); 2772 } 2773 2774 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2775 // name and signature, as interpreted relative to the given class loader. 2776 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2777 Handle bootstrap_specifier, 2778 Symbol* name, 2779 Symbol* type, 2780 Handle *appendix_result, 2781 Handle *method_type_result, 2782 TRAPS) { 2783 methodHandle empty; 2784 Handle bsm, info; 2785 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2786 bsm = bootstrap_specifier; 2787 } else { 2788 assert(bootstrap_specifier->is_objArray(), ""); 2789 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2790 int len = args->length(); 2791 assert(len >= 1, ""); 2792 bsm = Handle(THREAD, args->obj_at(0)); 2793 if (len > 1) { 2794 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2795 for (int i = 1; i < len; i++) 2796 args1->obj_at_put(i-1, args->obj_at(i)); 2797 info = Handle(THREAD, args1); 2798 } 2799 } 2800 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2801 "caller must supply a valid BSM"); 2802 2803 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2804 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2805 2806 // This should not happen. JDK code should take care of that. 2807 if (caller.is_null() || method_type.is_null()) { 2808 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2809 } 2810 2811 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2812 assert(appendix_box->obj_at(0) == NULL, ""); 2813 2814 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2815 JavaCallArguments args; 2816 args.push_oop(caller->java_mirror()); 2817 args.push_oop(bsm()); 2818 args.push_oop(method_name()); 2819 args.push_oop(method_type()); 2820 args.push_oop(info()); 2821 args.push_oop(appendix_box); 2822 JavaValue result(T_OBJECT); 2823 JavaCalls::call_static(&result, 2824 SystemDictionary::MethodHandleNatives_klass(), 2825 vmSymbols::linkCallSite_name(), 2826 vmSymbols::linkCallSite_signature(), 2827 &args, CHECK_(empty)); 2828 Handle mname(THREAD, (oop) result.get_jobject()); 2829 (*method_type_result) = method_type; 2830 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2831 } 2832 2833 // Since the identity hash code for symbols changes when the symbols are 2834 // moved from the regular perm gen (hash in the mark word) to the shared 2835 // spaces (hash is the address), the classes loaded into the dictionary 2836 // may be in the wrong buckets. 2837 2838 void SystemDictionary::reorder_dictionary() { 2839 dictionary()->reorder_dictionary(); 2840 } 2841 2842 2843 void SystemDictionary::copy_buckets(char** top, char* end) { 2844 dictionary()->copy_buckets(top, end); 2845 } 2846 2847 2848 void SystemDictionary::copy_table(char** top, char* end) { 2849 dictionary()->copy_table(top, end); 2850 } 2851 2852 2853 void SystemDictionary::reverse() { 2854 dictionary()->reverse(); 2855 } 2856 2857 int SystemDictionary::number_of_classes() { 2858 return dictionary()->number_of_entries(); 2859 } 2860 2861 2862 // ---------------------------------------------------------------------------- 2863 void SystemDictionary::print_shared(bool details) { 2864 shared_dictionary()->print(details); 2865 } 2866 2867 void SystemDictionary::print(bool details) { 2868 dictionary()->print(details); 2869 2870 // Placeholders 2871 GCMutexLocker mu(SystemDictionary_lock); 2872 placeholders()->print(); 2873 2874 // loader constraints - print under SD_lock 2875 constraints()->print(); 2876 } 2877 2878 2879 void SystemDictionary::verify() { 2880 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2881 guarantee(constraints() != NULL, 2882 "Verify of loader constraints failed"); 2883 guarantee(dictionary()->number_of_entries() >= 0 && 2884 placeholders()->number_of_entries() >= 0, 2885 "Verify of system dictionary failed"); 2886 2887 // Verify dictionary 2888 dictionary()->verify(); 2889 2890 GCMutexLocker mu(SystemDictionary_lock); 2891 placeholders()->verify(); 2892 2893 // Verify constraint table 2894 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2895 constraints()->verify(dictionary(), placeholders()); 2896 } 2897 2898 // caller needs ResourceMark 2899 const char* SystemDictionary::loader_name(const oop loader) { 2900 return ((loader) == NULL ? "<bootloader>" : 2901 InstanceKlass::cast((loader)->klass())->name()->as_C_string()); 2902 } 2903 2904 // caller needs ResourceMark 2905 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { 2906 return (loader_data->class_loader() == NULL ? "<bootloader>" : 2907 SystemDictionary::loader_name(loader_data->class_loader())); 2908 }