1 /* 2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "aot/aotLoader.hpp" 27 #include "classfile/classFileParser.hpp" 28 #include "classfile/classFileStream.hpp" 29 #include "classfile/classLoader.hpp" 30 #include "classfile/classLoaderData.inline.hpp" 31 #include "classfile/classLoaderExt.hpp" 32 #include "classfile/dictionary.hpp" 33 #include "classfile/javaClasses.inline.hpp" 34 #include "classfile/klassFactory.hpp" 35 #include "classfile/loaderConstraints.hpp" 36 #include "classfile/packageEntry.hpp" 37 #include "classfile/placeholders.hpp" 38 #include "classfile/protectionDomainCache.hpp" 39 #include "classfile/resolutionErrors.hpp" 40 #include "classfile/stringTable.hpp" 41 #include "classfile/systemDictionary.hpp" 42 #include "classfile/vmSymbols.hpp" 43 #include "code/codeCache.hpp" 44 #include "compiler/compileBroker.hpp" 45 #include "gc/shared/gcLocker.hpp" 46 #include "gc/shared/gcTraceTime.inline.hpp" 47 #include "interpreter/bytecodeStream.hpp" 48 #include "interpreter/interpreter.hpp" 49 #include "logging/log.hpp" 50 #include "memory/filemap.hpp" 51 #include "memory/oopFactory.hpp" 52 #include "memory/resourceArea.hpp" 53 #include "oops/instanceKlass.hpp" 54 #include "oops/instanceRefKlass.hpp" 55 #include "oops/klass.inline.hpp" 56 #include "oops/methodData.hpp" 57 #include "oops/objArrayKlass.hpp" 58 #include "oops/objArrayOop.inline.hpp" 59 #include "oops/oop.inline.hpp" 60 #include "oops/symbol.hpp" 61 #include "oops/typeArrayKlass.hpp" 62 #include "prims/jvm.h" 63 #include "prims/jvmtiEnvBase.hpp" 64 #include "prims/resolvedMethodTable.hpp" 65 #include "prims/methodHandles.hpp" 66 #include "runtime/arguments.hpp" 67 #include "runtime/biasedLocking.hpp" 68 #include "runtime/fieldType.hpp" 69 #include "runtime/handles.inline.hpp" 70 #include "runtime/java.hpp" 71 #include "runtime/javaCalls.hpp" 72 #include "runtime/mutexLocker.hpp" 73 #include "runtime/orderAccess.inline.hpp" 74 #include "runtime/signature.hpp" 75 #include "services/classLoadingService.hpp" 76 #include "services/threadService.hpp" 77 #include "trace/traceMacros.hpp" 78 #include "utilities/macros.hpp" 79 #include "utilities/ticks.hpp" 80 #if INCLUDE_CDS 81 #include "classfile/sharedClassUtil.hpp" 82 #include "classfile/systemDictionaryShared.hpp" 83 #endif 84 #if INCLUDE_JVMCI 85 #include "jvmci/jvmciRuntime.hpp" 86 #endif 87 #if INCLUDE_TRACE 88 #include "trace/tracing.hpp" 89 #endif 90 91 PlaceholderTable* SystemDictionary::_placeholders = NULL; 92 Dictionary* SystemDictionary::_shared_dictionary = NULL; 93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; 97 98 int SystemDictionary::_number_of_modifications = 0; 99 oop SystemDictionary::_system_loader_lock_obj = NULL; 100 101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 102 = { NULL /*, NULL...*/ }; 103 104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 105 106 oop SystemDictionary::_java_system_loader = NULL; 107 108 bool SystemDictionary::_has_loadClassInternal = false; 109 bool SystemDictionary::_has_checkPackageAccess = false; 110 111 // lazily initialized klass variables 112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 113 114 // Default ProtectionDomainCacheSize value 115 116 const int defaultProtectionDomainCacheSize = 1009; 117 118 119 // ---------------------------------------------------------------------------- 120 // Java-level SystemLoader 121 122 oop SystemDictionary::java_system_loader() { 123 return _java_system_loader; 124 } 125 126 void SystemDictionary::compute_java_system_loader(TRAPS) { 127 Klass* system_klass = WK_KLASS(ClassLoader_klass); 128 JavaValue result(T_OBJECT); 129 JavaCalls::call_static(&result, 130 WK_KLASS(ClassLoader_klass), 131 vmSymbols::getSystemClassLoader_name(), 132 vmSymbols::void_classloader_signature(), 133 CHECK); 134 135 _java_system_loader = (oop)result.get_jobject(); 136 137 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) 138 } 139 140 141 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 142 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 143 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD); 144 } 145 146 // ---------------------------------------------------------------------------- 147 // Parallel class loading check 148 149 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 150 if (UnsyncloadClass || class_loader.is_null()) return true; 151 if (AlwaysLockClassLoader) return false; 152 return java_lang_ClassLoader::parallelCapable(class_loader()); 153 } 154 // ---------------------------------------------------------------------------- 155 // ParallelDefineClass flag does not apply to bootclass loader 156 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 157 if (class_loader.is_null()) return false; 158 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 159 return true; 160 } 161 return false; 162 } 163 164 // Returns true if the passed class loader is the builtin application class loader 165 // or a custom system class loader. A customer system class loader can be 166 // specified via -Djava.system.class.loader. 167 bool SystemDictionary::is_system_class_loader(oop class_loader) { 168 if (class_loader == NULL) { 169 return false; 170 } 171 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 172 class_loader == _java_system_loader); 173 } 174 175 // Returns true if the passed class loader is the platform class loader. 176 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 177 if (class_loader == NULL) { 178 return false; 179 } 180 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 181 } 182 183 // ---------------------------------------------------------------------------- 184 // Resolving of classes 185 186 // Forwards to resolve_or_null 187 188 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 189 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 190 if (HAS_PENDING_EXCEPTION || klass == NULL) { 191 // can return a null klass 192 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 193 } 194 return klass; 195 } 196 197 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 198 bool throw_error, 199 Klass* klass, TRAPS) { 200 if (HAS_PENDING_EXCEPTION) { 201 // If we have a pending exception we forward it to the caller, unless throw_error is true, 202 // in which case we have to check whether the pending exception is a ClassNotFoundException, 203 // and if so convert it to a NoClassDefFoundError 204 // And chain the original ClassNotFoundException 205 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 206 ResourceMark rm(THREAD); 207 assert(klass == NULL, "Should not have result with exception pending"); 208 Handle e(THREAD, PENDING_EXCEPTION); 209 CLEAR_PENDING_EXCEPTION; 210 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 211 } else { 212 return NULL; 213 } 214 } 215 // Class not found, throw appropriate error or exception depending on value of throw_error 216 if (klass == NULL) { 217 ResourceMark rm(THREAD); 218 if (throw_error) { 219 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 220 } else { 221 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 222 } 223 } 224 return klass; 225 } 226 227 228 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 229 bool throw_error, TRAPS) 230 { 231 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 232 } 233 234 235 // Forwards to resolve_instance_class_or_null 236 237 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 238 assert(THREAD->can_call_java(), 239 "can not load classes with compiler thread: class=%s, classloader=%s", 240 class_name->as_C_string(), 241 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 242 if (FieldType::is_array(class_name)) { 243 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 244 } else if (FieldType::is_obj(class_name)) { 245 ResourceMark rm(THREAD); 246 // Ignore wrapping L and ;. 247 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 248 class_name->utf8_length() - 2, CHECK_NULL); 249 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 250 } else { 251 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 252 } 253 } 254 255 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 256 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 257 } 258 259 // Forwards to resolve_instance_class_or_null 260 261 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 262 Handle class_loader, 263 Handle protection_domain, 264 TRAPS) { 265 assert(FieldType::is_array(class_name), "must be array"); 266 Klass* k = NULL; 267 FieldArrayInfo fd; 268 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 269 // of this call 270 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 271 if (t == T_OBJECT) { 272 // naked oop "k" is OK here -- we assign back into it 273 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 274 class_loader, 275 protection_domain, 276 CHECK_NULL); 277 if (k != NULL) { 278 k = k->array_klass(fd.dimension(), CHECK_NULL); 279 } 280 } else { 281 k = Universe::typeArrayKlassObj(t); 282 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 283 } 284 return k; 285 } 286 287 288 // Must be called for any super-class or super-interface resolution 289 // during class definition to allow class circularity checking 290 // super-interface callers: 291 // parse_interfaces - for defineClass & jvmtiRedefineClasses 292 // super-class callers: 293 // ClassFileParser - for defineClass & jvmtiRedefineClasses 294 // load_shared_class - while loading a class from shared archive 295 // resolve_instance_class_or_null: 296 // via: handle_parallel_super_load 297 // when resolving a class that has an existing placeholder with 298 // a saved superclass [i.e. a defineClass is currently in progress] 299 // if another thread is trying to resolve the class, it must do 300 // super-class checks on its own thread to catch class circularity 301 // This last call is critical in class circularity checking for cases 302 // where classloading is delegated to different threads and the 303 // classloader lock is released. 304 // Take the case: Base->Super->Base 305 // 1. If thread T1 tries to do a defineClass of class Base 306 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 307 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 308 // so it tries to load Super 309 // 3. If we load the class internally, or user classloader uses same thread 310 // loadClassFromxxx or defineClass via parseClassFile Super ... 311 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 312 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 313 // 3.4 calls resolve_super_or_fail Base 314 // 3.5 finds T1,Base -> throws class circularity 315 //OR 4. If T2 tries to resolve Super via defineClass Super ... 316 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 317 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 318 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 319 // 4.4 finds T2, Super -> throws class circularity 320 // Must be called, even if superclass is null, since this is 321 // where the placeholder entry is created which claims this 322 // thread is loading this class/classloader. 323 // Be careful when modifying this code: once you have run 324 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 325 // you need to find_and_remove it before returning. 326 // So be careful to not exit with a CHECK_ macro betweeen these calls. 327 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 328 Symbol* class_name, 329 Handle class_loader, 330 Handle protection_domain, 331 bool is_superclass, 332 TRAPS) { 333 #if INCLUDE_CDS 334 if (DumpSharedSpaces) { 335 // Special processing for CDS dump time. 336 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 337 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 338 if (k) { 339 return k; 340 } 341 } 342 #endif // INCLUDE_CDS 343 344 // Double-check, if child class is already loaded, just return super-class,interface 345 // Don't add a placedholder if already loaded, i.e. already in system dictionary 346 // Make sure there's a placeholder for the *child* before resolving. 347 // Used as a claim that this thread is currently loading superclass/classloader 348 // Used here for ClassCircularity checks and also for heap verification 349 // (every InstanceKlass in the heap needs to be in the system dictionary 350 // or have a placeholder). 351 // Must check ClassCircularity before checking if super class is already loaded 352 // 353 // We might not already have a placeholder if this child_name was 354 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 355 // the name of the class might not be known until the stream is actually 356 // parsed. 357 // Bugs 4643874, 4715493 358 359 ClassLoaderData* loader_data = class_loader_data(class_loader); 360 Dictionary* dictionary = loader_data->dictionary(); 361 unsigned int d_hash = dictionary->compute_hash(child_name); 362 int d_index = dictionary->hash_to_index(d_hash); 363 unsigned int p_hash = placeholders()->compute_hash(child_name); 364 int p_index = placeholders()->hash_to_index(p_hash); 365 // can't throw error holding a lock 366 bool child_already_loaded = false; 367 bool throw_circularity_error = false; 368 { 369 MutexLocker mu(SystemDictionary_lock, THREAD); 370 Klass* childk = find_class(d_index, d_hash, child_name, dictionary); 371 Klass* quicksuperk; 372 // to support // loading: if child done loading, just return superclass 373 // if class_name, & class_loader don't match: 374 // if initial define, SD update will give LinkageError 375 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 376 // so we don't throw an exception here. 377 // see: nsk redefclass014 & java.lang.instrument Instrument032 378 if ((childk != NULL ) && (is_superclass) && 379 ((quicksuperk = childk->super()) != NULL) && 380 381 ((quicksuperk->name() == class_name) && 382 (quicksuperk->class_loader() == class_loader()))) { 383 return quicksuperk; 384 } else { 385 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 386 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 387 throw_circularity_error = true; 388 } 389 } 390 if (!throw_circularity_error) { 391 // Be careful not to exit resolve_super 392 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 393 } 394 } 395 if (throw_circularity_error) { 396 ResourceMark rm(THREAD); 397 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 398 } 399 400 // java.lang.Object should have been found above 401 assert(class_name != NULL, "null super class for resolving"); 402 // Resolve the super class or interface, check results on return 403 Klass* superk = SystemDictionary::resolve_or_null(class_name, 404 class_loader, 405 protection_domain, 406 THREAD); 407 408 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 409 // It is no longer necessary to keep the placeholder table alive until update_dictionary 410 // or error. GC used to walk the placeholder table as strong roots. 411 // The instanceKlass is kept alive because the class loader is on the stack, 412 // which keeps the loader_data alive, as well as all instanceKlasses in 413 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 414 { 415 MutexLocker mu(SystemDictionary_lock, THREAD); 416 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 417 SystemDictionary_lock->notify_all(); 418 } 419 if (HAS_PENDING_EXCEPTION || superk == NULL) { 420 // can null superk 421 superk = handle_resolution_exception(class_name, true, superk, THREAD); 422 } 423 424 return superk; 425 } 426 427 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 428 Handle class_loader, 429 Handle protection_domain, 430 TRAPS) { 431 if(!has_checkPackageAccess()) return; 432 433 // Now we have to call back to java to check if the initating class has access 434 JavaValue result(T_VOID); 435 if (log_is_enabled(Debug, protectiondomain)) { 436 ResourceMark rm; 437 // Print out trace information 438 outputStream* log = Log(protectiondomain)::debug_stream(); 439 log->print_cr("Checking package access"); 440 log->print("class loader: "); class_loader()->print_value_on(log); 441 log->print(" protection domain: "); protection_domain()->print_value_on(log); 442 log->print(" loading: "); klass->print_value_on(log); 443 log->cr(); 444 } 445 446 // This handle and the class_loader handle passed in keeps this class from 447 // being unloaded through several GC points. 448 Handle mirror(THREAD, klass->java_mirror()); 449 450 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 451 JavaCalls::call_special(&result, 452 class_loader, 453 system_loader, 454 vmSymbols::checkPackageAccess_name(), 455 vmSymbols::class_protectiondomain_signature(), 456 mirror, 457 protection_domain, 458 THREAD); 459 460 if (HAS_PENDING_EXCEPTION) { 461 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 462 } else { 463 log_debug(protectiondomain)("granted"); 464 } 465 466 if (HAS_PENDING_EXCEPTION) return; 467 468 // If no exception has been thrown, we have validated the protection domain 469 // Insert the protection domain of the initiating class into the set. 470 { 471 ClassLoaderData* loader_data = class_loader_data(class_loader); 472 Dictionary* dictionary = loader_data->dictionary(); 473 474 Symbol* kn = klass->name(); 475 unsigned int d_hash = dictionary->compute_hash(kn); 476 int d_index = dictionary->hash_to_index(d_hash); 477 478 MutexLocker mu(SystemDictionary_lock, THREAD); 479 dictionary->add_protection_domain(d_index, d_hash, klass, 480 protection_domain, THREAD); 481 } 482 } 483 484 // We only get here if this thread finds that another thread 485 // has already claimed the placeholder token for the current operation, 486 // but that other thread either never owned or gave up the 487 // object lock 488 // Waits on SystemDictionary_lock to indicate placeholder table updated 489 // On return, caller must recheck placeholder table state 490 // 491 // We only get here if 492 // 1) custom classLoader, i.e. not bootstrap classloader 493 // 2) UnsyncloadClass not set 494 // 3) custom classLoader has broken the class loader objectLock 495 // so another thread got here in parallel 496 // 497 // lockObject must be held. 498 // Complicated dance due to lock ordering: 499 // Must first release the classloader object lock to 500 // allow initial definer to complete the class definition 501 // and to avoid deadlock 502 // Reclaim classloader lock object with same original recursion count 503 // Must release SystemDictionary_lock after notify, since 504 // class loader lock must be claimed before SystemDictionary_lock 505 // to prevent deadlocks 506 // 507 // The notify allows applications that did an untimed wait() on 508 // the classloader object lock to not hang. 509 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 510 assert_lock_strong(SystemDictionary_lock); 511 512 bool calledholdinglock 513 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 514 assert(calledholdinglock,"must hold lock for notify"); 515 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 516 ObjectSynchronizer::notifyall(lockObject, THREAD); 517 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 518 SystemDictionary_lock->wait(); 519 SystemDictionary_lock->unlock(); 520 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 521 SystemDictionary_lock->lock(); 522 } 523 524 // If the class in is in the placeholder table, class loading is in progress 525 // For cases where the application changes threads to load classes, it 526 // is critical to ClassCircularity detection that we try loading 527 // the superclass on the same thread internally, so we do parallel 528 // super class loading here. 529 // This also is critical in cases where the original thread gets stalled 530 // even in non-circularity situations. 531 // Note: must call resolve_super_or_fail even if null super - 532 // to force placeholder entry creation for this class for circularity detection 533 // Caller must check for pending exception 534 // Returns non-null Klass* if other thread has completed load 535 // and we are done, 536 // If return null Klass* and no pending exception, the caller must load the class 537 InstanceKlass* SystemDictionary::handle_parallel_super_load( 538 Symbol* name, Symbol* superclassname, Handle class_loader, 539 Handle protection_domain, Handle lockObject, TRAPS) { 540 541 ClassLoaderData* loader_data = class_loader_data(class_loader); 542 Dictionary* dictionary = loader_data->dictionary(); 543 unsigned int d_hash = dictionary->compute_hash(name); 544 int d_index = dictionary->hash_to_index(d_hash); 545 unsigned int p_hash = placeholders()->compute_hash(name); 546 int p_index = placeholders()->hash_to_index(p_hash); 547 548 // superk is not used, resolve_super called for circularity check only 549 // This code is reached in two situations. One if this thread 550 // is loading the same class twice (e.g. ClassCircularity, or 551 // java.lang.instrument). 552 // The second is if another thread started the resolve_super first 553 // and has not yet finished. 554 // In both cases the original caller will clean up the placeholder 555 // entry on error. 556 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 557 superclassname, 558 class_loader, 559 protection_domain, 560 true, 561 CHECK_NULL); 562 563 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 564 // Serial class loaders and bootstrap classloader do wait for superclass loads 565 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 566 MutexLocker mu(SystemDictionary_lock, THREAD); 567 // Check if classloading completed while we were loading superclass or waiting 568 return find_class(d_index, d_hash, name, dictionary); 569 } 570 571 // must loop to both handle other placeholder updates 572 // and spurious notifications 573 bool super_load_in_progress = true; 574 PlaceholderEntry* placeholder; 575 while (super_load_in_progress) { 576 MutexLocker mu(SystemDictionary_lock, THREAD); 577 // Check if classloading completed while we were loading superclass or waiting 578 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary); 579 if (check != NULL) { 580 // Klass is already loaded, so just return it 581 return check; 582 } else { 583 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 584 if (placeholder && placeholder->super_load_in_progress() ){ 585 // Before UnsyncloadClass: 586 // We only get here if the application has released the 587 // classloader lock when another thread was in the middle of loading a 588 // superclass/superinterface for this class, and now 589 // this thread is also trying to load this class. 590 // To minimize surprises, the first thread that started to 591 // load a class should be the one to complete the loading 592 // with the classfile it initially expected. 593 // This logic has the current thread wait once it has done 594 // all the superclass/superinterface loading it can, until 595 // the original thread completes the class loading or fails 596 // If it completes we will use the resulting InstanceKlass 597 // which we will find below in the systemDictionary. 598 // We also get here for parallel bootstrap classloader 599 if (class_loader.is_null()) { 600 SystemDictionary_lock->wait(); 601 } else { 602 double_lock_wait(lockObject, THREAD); 603 } 604 } else { 605 // If not in SD and not in PH, other thread's load must have failed 606 super_load_in_progress = false; 607 } 608 } 609 } 610 return NULL; 611 } 612 613 static void post_class_load_event(const Ticks& start_time, 614 InstanceKlass* k, 615 const ClassLoaderData* init_cld) { 616 #if INCLUDE_TRACE 617 EventClassLoad event(UNTIMED); 618 if (event.should_commit()) { 619 event.set_starttime(start_time); 620 event.set_loadedClass(k); 621 event.set_definingClassLoader(k->class_loader_data()); 622 event.set_initiatingClassLoader(init_cld); 623 event.commit(); 624 } 625 #endif // INCLUDE_TRACE 626 } 627 628 static void class_define_event(InstanceKlass* k, 629 const ClassLoaderData* def_cld) { 630 #if INCLUDE_TRACE 631 EventClassDefine event; 632 if (event.should_commit()) { 633 event.set_definedClass(k); 634 event.set_definingClassLoader(def_cld); 635 event.commit(); 636 } 637 #endif // INCLUDE_TRACE 638 } 639 640 // Be careful when modifying this code: once you have run 641 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 642 // you need to find_and_remove it before returning. 643 // So be careful to not exit with a CHECK_ macro betweeen these calls. 644 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 645 Handle class_loader, 646 Handle protection_domain, 647 TRAPS) { 648 assert(name != NULL && !FieldType::is_array(name) && 649 !FieldType::is_obj(name), "invalid class name"); 650 651 Ticks class_load_start_time = Ticks::now(); 652 653 HandleMark hm(THREAD); 654 655 // Fix for 4474172; see evaluation for more details 656 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 657 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 658 Dictionary* dictionary = loader_data->dictionary(); 659 660 // Do lookup to see if class already exist and the protection domain 661 // has the right access 662 // This call uses find which checks protection domain already matches 663 // All subsequent calls use find_class, and set has_loaded_class so that 664 // before we return a result we call out to java to check for valid protection domain 665 // to allow returning the Klass* and add it to the pd_set if it is valid 666 unsigned int d_hash = dictionary->compute_hash(name); 667 int d_index = dictionary->hash_to_index(d_hash); 668 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain); 669 if (probe != NULL) return probe; 670 671 672 // Non-bootstrap class loaders will call out to class loader and 673 // define via jvm/jni_DefineClass which will acquire the 674 // class loader object lock to protect against multiple threads 675 // defining the class in parallel by accident. 676 // This lock must be acquired here so the waiter will find 677 // any successful result in the SystemDictionary and not attempt 678 // the define 679 // ParallelCapable Classloaders and the bootstrap classloader, 680 // or all classloaders with UnsyncloadClass do not acquire lock here 681 bool DoObjectLock = true; 682 if (is_parallelCapable(class_loader)) { 683 DoObjectLock = false; 684 } 685 686 unsigned int p_hash = placeholders()->compute_hash(name); 687 int p_index = placeholders()->hash_to_index(p_hash); 688 689 // Class is not in SystemDictionary so we have to do loading. 690 // Make sure we are synchronized on the class loader before we proceed 691 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 692 check_loader_lock_contention(lockObject, THREAD); 693 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 694 695 // Check again (after locking) if class already exist in SystemDictionary 696 bool class_has_been_loaded = false; 697 bool super_load_in_progress = false; 698 bool havesupername = false; 699 InstanceKlass* k = NULL; 700 PlaceholderEntry* placeholder; 701 Symbol* superclassname = NULL; 702 703 { 704 MutexLocker mu(SystemDictionary_lock, THREAD); 705 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary); 706 if (check != NULL) { 707 // Klass is already loaded, so just return it 708 class_has_been_loaded = true; 709 k = check; 710 } else { 711 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 712 if (placeholder && placeholder->super_load_in_progress()) { 713 super_load_in_progress = true; 714 if (placeholder->havesupername() == true) { 715 superclassname = placeholder->supername(); 716 havesupername = true; 717 } 718 } 719 } 720 } 721 722 // If the class is in the placeholder table, class loading is in progress 723 if (super_load_in_progress && havesupername==true) { 724 k = handle_parallel_super_load(name, 725 superclassname, 726 class_loader, 727 protection_domain, 728 lockObject, THREAD); 729 if (HAS_PENDING_EXCEPTION) { 730 return NULL; 731 } 732 if (k != NULL) { 733 class_has_been_loaded = true; 734 } 735 } 736 737 bool throw_circularity_error = false; 738 if (!class_has_been_loaded) { 739 bool load_instance_added = false; 740 741 // add placeholder entry to record loading instance class 742 // Five cases: 743 // All cases need to prevent modifying bootclasssearchpath 744 // in parallel with a classload of same classname 745 // Redefineclasses uses existence of the placeholder for the duration 746 // of the class load to prevent concurrent redefinition of not completely 747 // defined classes. 748 // case 1. traditional classloaders that rely on the classloader object lock 749 // - no other need for LOAD_INSTANCE 750 // case 2. traditional classloaders that break the classloader object lock 751 // as a deadlock workaround. Detection of this case requires that 752 // this check is done while holding the classloader object lock, 753 // and that lock is still held when calling classloader's loadClass. 754 // For these classloaders, we ensure that the first requestor 755 // completes the load and other requestors wait for completion. 756 // case 3. UnsyncloadClass - don't use objectLocker 757 // With this flag, we allow parallel classloading of a 758 // class/classloader pair 759 // case4. Bootstrap classloader - don't own objectLocker 760 // This classloader supports parallelism at the classloader level, 761 // but only allows a single load of a class/classloader pair. 762 // No performance benefit and no deadlock issues. 763 // case 5. parallelCapable user level classloaders - without objectLocker 764 // Allow parallel classloading of a class/classloader pair 765 766 { 767 MutexLocker mu(SystemDictionary_lock, THREAD); 768 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 769 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 770 if (oldprobe) { 771 // only need check_seen_thread once, not on each loop 772 // 6341374 java/lang/Instrument with -Xcomp 773 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 774 throw_circularity_error = true; 775 } else { 776 // case 1: traditional: should never see load_in_progress. 777 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 778 779 // case 4: bootstrap classloader: prevent futile classloading, 780 // wait on first requestor 781 if (class_loader.is_null()) { 782 SystemDictionary_lock->wait(); 783 } else { 784 // case 2: traditional with broken classloader lock. wait on first 785 // requestor. 786 double_lock_wait(lockObject, THREAD); 787 } 788 // Check if classloading completed while we were waiting 789 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary); 790 if (check != NULL) { 791 // Klass is already loaded, so just return it 792 k = check; 793 class_has_been_loaded = true; 794 } 795 // check if other thread failed to load and cleaned up 796 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 797 } 798 } 799 } 800 } 801 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 802 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 803 // LOAD_INSTANCE in parallel 804 805 if (!throw_circularity_error && !class_has_been_loaded) { 806 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 807 load_instance_added = true; 808 // For class loaders that do not acquire the classloader object lock, 809 // if they did not catch another thread holding LOAD_INSTANCE, 810 // need a check analogous to the acquire ObjectLocker/find_class 811 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 812 // one final check if the load has already completed 813 // class loaders holding the ObjectLock shouldn't find the class here 814 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary); 815 if (check != NULL) { 816 // Klass is already loaded, so return it after checking/adding protection domain 817 k = check; 818 class_has_been_loaded = true; 819 } 820 } 821 } 822 823 // must throw error outside of owning lock 824 if (throw_circularity_error) { 825 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 826 ResourceMark rm(THREAD); 827 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 828 } 829 830 if (!class_has_been_loaded) { 831 832 // Do actual loading 833 k = load_instance_class(name, class_loader, THREAD); 834 835 // For UnsyncloadClass only 836 // If they got a linkageError, check if a parallel class load succeeded. 837 // If it did, then for bytecode resolution the specification requires 838 // that we return the same result we did for the other thread, i.e. the 839 // successfully loaded InstanceKlass 840 // Should not get here for classloaders that support parallelism 841 // with the new cleaner mechanism, even with AllowParallelDefineClass 842 // Bootstrap goes through here to allow for an extra guarantee check 843 if (UnsyncloadClass || (class_loader.is_null())) { 844 if (k == NULL && HAS_PENDING_EXCEPTION 845 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 846 MutexLocker mu(SystemDictionary_lock, THREAD); 847 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary); 848 if (check != NULL) { 849 // Klass is already loaded, so just use it 850 k = check; 851 CLEAR_PENDING_EXCEPTION; 852 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 853 } 854 } 855 } 856 857 // If everything was OK (no exceptions, no null return value), and 858 // class_loader is NOT the defining loader, do a little more bookkeeping. 859 if (!HAS_PENDING_EXCEPTION && k != NULL && 860 k->class_loader() != class_loader()) { 861 862 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 863 864 // Need to check for a PENDING_EXCEPTION again; check_constraints 865 // can throw and doesn't use the CHECK macro. 866 if (!HAS_PENDING_EXCEPTION) { 867 { // Grabbing the Compile_lock prevents systemDictionary updates 868 // during compilations. 869 MutexLocker mu(Compile_lock, THREAD); 870 update_dictionary(d_index, d_hash, p_index, p_hash, 871 k, class_loader, THREAD); 872 } 873 874 if (JvmtiExport::should_post_class_load()) { 875 Thread *thread = THREAD; 876 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 877 JvmtiExport::post_class_load((JavaThread *) thread, k); 878 } 879 } 880 } 881 } // load_instance_class 882 883 if (load_instance_added == true) { 884 // clean up placeholder entries for LOAD_INSTANCE success or error 885 // This brackets the SystemDictionary updates for both defining 886 // and initiating loaders 887 MutexLocker mu(SystemDictionary_lock, THREAD); 888 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 889 SystemDictionary_lock->notify_all(); 890 } 891 } 892 893 if (HAS_PENDING_EXCEPTION || k == NULL) { 894 return NULL; 895 } 896 897 post_class_load_event(class_load_start_time, k, loader_data); 898 899 #ifdef ASSERT 900 { 901 ClassLoaderData* loader_data = k->class_loader_data(); 902 MutexLocker mu(SystemDictionary_lock, THREAD); 903 Klass* kk = find_class(name, loader_data); 904 assert(kk == k, "should be present in dictionary"); 905 } 906 #endif 907 908 // return if the protection domain in NULL 909 if (protection_domain() == NULL) return k; 910 911 // Check the protection domain has the right access 912 { 913 MutexLocker mu(SystemDictionary_lock, THREAD); 914 if (dictionary->is_valid_protection_domain(d_index, d_hash, name, 915 protection_domain)) { 916 return k; 917 } 918 } 919 920 // Verify protection domain. If it fails an exception is thrown 921 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 922 923 return k; 924 } 925 926 927 // This routine does not lock the system dictionary. 928 // 929 // Since readers don't hold a lock, we must make sure that system 930 // dictionary entries are only removed at a safepoint (when only one 931 // thread is running), and are added to in a safe way (all links must 932 // be updated in an MT-safe manner). 933 // 934 // Callers should be aware that an entry could be added just after 935 // _dictionary->bucket(index) is read here, so the caller will not see 936 // the new entry. 937 938 Klass* SystemDictionary::find(Symbol* class_name, 939 Handle class_loader, 940 Handle protection_domain, 941 TRAPS) { 942 943 // The result of this call should be consistent with the result 944 // of the call to resolve_instance_class_or_null(). 945 // See evaluation 6790209 and 4474172 for more details. 946 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 947 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 948 949 if (loader_data == NULL) { 950 // If the ClassLoaderData has not been setup, 951 // then the class loader has no entries in the dictionary. 952 return NULL; 953 } 954 955 Dictionary* dictionary = loader_data->dictionary_or_null(); 956 // If ClassLoaderData has no dictionary, the class won't be found in it 957 if (dictionary == NULL) { 958 return NULL; 959 } 960 961 unsigned int d_hash = dictionary->compute_hash(class_name); 962 int d_index = dictionary->hash_to_index(d_hash); 963 return dictionary->find(d_index, d_hash, class_name, 964 protection_domain); 965 } 966 967 968 // Look for a loaded instance or array klass by name. Do not do any loading. 969 // return NULL in case of error. 970 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 971 Handle class_loader, 972 Handle protection_domain, 973 TRAPS) { 974 Klass* k = NULL; 975 assert(class_name != NULL, "class name must be non NULL"); 976 977 if (FieldType::is_array(class_name)) { 978 // The name refers to an array. Parse the name. 979 // dimension and object_key in FieldArrayInfo are assigned as a 980 // side-effect of this call 981 FieldArrayInfo fd; 982 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 983 if (t != T_OBJECT) { 984 k = Universe::typeArrayKlassObj(t); 985 } else { 986 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 987 } 988 if (k != NULL) { 989 k = k->array_klass_or_null(fd.dimension()); 990 } 991 } else { 992 k = find(class_name, class_loader, protection_domain, THREAD); 993 } 994 return k; 995 } 996 997 // Note: this method is much like resolve_from_stream, but 998 // does not publish the classes via the SystemDictionary. 999 // Handles unsafe_DefineAnonymousClass and redefineclasses 1000 // RedefinedClasses do not add to the class hierarchy 1001 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 1002 Handle class_loader, 1003 Handle protection_domain, 1004 ClassFileStream* st, 1005 const InstanceKlass* host_klass, 1006 GrowableArray<Handle>* cp_patches, 1007 TRAPS) { 1008 1009 Ticks class_load_start_time = Ticks::now(); 1010 1011 ClassLoaderData* loader_data; 1012 if (host_klass != NULL) { 1013 // Create a new CLD for anonymous class, that uses the same class loader 1014 // as the host_klass 1015 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 1016 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping"); 1017 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 1018 } else { 1019 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1020 } 1021 1022 assert(st != NULL, "invariant"); 1023 assert(st->need_verify(), "invariant"); 1024 1025 // Parse stream and create a klass. 1026 // Note that we do this even though this klass might 1027 // already be present in the SystemDictionary, otherwise we would not 1028 // throw potential ClassFormatErrors. 1029 1030 InstanceKlass* k = KlassFactory::create_from_stream(st, 1031 class_name, 1032 loader_data, 1033 protection_domain, 1034 host_klass, 1035 cp_patches, 1036 CHECK_NULL); 1037 1038 if (host_klass != NULL && k != NULL) { 1039 // If it's anonymous, initialize it now, since nobody else will. 1040 1041 { 1042 MutexLocker mu_r(Compile_lock, THREAD); 1043 1044 // Add to class hierarchy, initialize vtables, and do possible 1045 // deoptimizations. 1046 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1047 1048 // But, do not add to system dictionary. 1049 1050 // compiled code dependencies need to be validated anyway 1051 notice_modification(); 1052 } 1053 1054 // Rewrite and patch constant pool here. 1055 k->link_class(CHECK_NULL); 1056 if (cp_patches != NULL) { 1057 k->constants()->patch_resolved_references(cp_patches); 1058 } 1059 k->eager_initialize(CHECK_NULL); 1060 1061 // notify jvmti 1062 if (JvmtiExport::should_post_class_load()) { 1063 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1064 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1065 } 1066 1067 post_class_load_event(class_load_start_time, k, loader_data); 1068 } 1069 assert(host_klass != NULL || NULL == cp_patches, 1070 "cp_patches only found with host_klass"); 1071 1072 return k; 1073 } 1074 1075 // Add a klass to the system from a stream (called by jni_DefineClass and 1076 // JVM_DefineClass). 1077 // Note: class_name can be NULL. In that case we do not know the name of 1078 // the class until we have parsed the stream. 1079 1080 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1081 Handle class_loader, 1082 Handle protection_domain, 1083 ClassFileStream* st, 1084 TRAPS) { 1085 1086 HandleMark hm(THREAD); 1087 1088 // Classloaders that support parallelism, e.g. bootstrap classloader, 1089 // or all classloaders with UnsyncloadClass do not acquire lock here 1090 bool DoObjectLock = true; 1091 if (is_parallelCapable(class_loader)) { 1092 DoObjectLock = false; 1093 } 1094 1095 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1096 1097 // Make sure we are synchronized on the class loader before we proceed 1098 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1099 check_loader_lock_contention(lockObject, THREAD); 1100 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1101 1102 assert(st != NULL, "invariant"); 1103 1104 // Parse the stream and create a klass. 1105 // Note that we do this even though this klass might 1106 // already be present in the SystemDictionary, otherwise we would not 1107 // throw potential ClassFormatErrors. 1108 InstanceKlass* k = NULL; 1109 1110 #if INCLUDE_CDS 1111 k = SystemDictionaryShared::lookup_from_stream(class_name, 1112 class_loader, 1113 protection_domain, 1114 st, 1115 CHECK_NULL); 1116 #endif 1117 1118 if (k == NULL) { 1119 if (st->buffer() == NULL) { 1120 return NULL; 1121 } 1122 k = KlassFactory::create_from_stream(st, 1123 class_name, 1124 loader_data, 1125 protection_domain, 1126 NULL, // host_klass 1127 NULL, // cp_patches 1128 CHECK_NULL); 1129 } 1130 1131 assert(k != NULL, "no klass created"); 1132 Symbol* h_name = k->name(); 1133 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1134 1135 // Add class just loaded 1136 // If a class loader supports parallel classloading handle parallel define requests 1137 // find_or_define_instance_class may return a different InstanceKlass 1138 if (is_parallelCapable(class_loader)) { 1139 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1140 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1141 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1142 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1143 loader_data->add_to_deallocate_list(k); 1144 k = defined_k; 1145 } 1146 } else { 1147 define_instance_class(k, THREAD); 1148 } 1149 1150 // If defining the class throws an exception register 'k' for cleanup. 1151 if (HAS_PENDING_EXCEPTION) { 1152 assert(k != NULL, "Must have an instance klass here!"); 1153 loader_data->add_to_deallocate_list(k); 1154 return NULL; 1155 } 1156 1157 // Make sure we have an entry in the SystemDictionary on success 1158 debug_only( { 1159 MutexLocker mu(SystemDictionary_lock, THREAD); 1160 1161 Klass* check = find_class(h_name, k->class_loader_data()); 1162 assert(check == k, "should be present in the dictionary"); 1163 } ); 1164 1165 return k; 1166 } 1167 1168 #if INCLUDE_CDS 1169 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1170 int number_of_entries) { 1171 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1172 "bad shared dictionary size."); 1173 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1174 _shared_dictionary_size, t, number_of_entries); 1175 } 1176 1177 1178 // If there is a shared dictionary, then find the entry for the 1179 // given shared system class, if any. 1180 1181 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1182 if (shared_dictionary() != NULL) { 1183 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1184 int d_index = shared_dictionary()->hash_to_index(d_hash); 1185 1186 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1187 } else { 1188 return NULL; 1189 } 1190 } 1191 1192 1193 // Load a class from the shared spaces (found through the shared system 1194 // dictionary). Force the superclass and all interfaces to be loaded. 1195 // Update the class definition to include sibling classes and no 1196 // subclasses (yet). [Classes in the shared space are not part of the 1197 // object hierarchy until loaded.] 1198 1199 InstanceKlass* SystemDictionary::load_shared_class( 1200 Symbol* class_name, Handle class_loader, TRAPS) { 1201 InstanceKlass* ik = find_shared_class(class_name); 1202 // Make sure we only return the boot class for the NULL classloader. 1203 if (ik != NULL && 1204 ik->is_shared_boot_class() && class_loader.is_null()) { 1205 Handle protection_domain; 1206 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1207 } 1208 return NULL; 1209 } 1210 1211 // Check if a shared class can be loaded by the specific classloader: 1212 // 1213 // NULL classloader: 1214 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1215 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1216 // be defined in an unnamed module. 1217 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1218 InstanceKlass* ik, 1219 Handle class_loader, TRAPS) { 1220 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1221 "Cannot use sharing if java.base is patched"); 1222 ResourceMark rm; 1223 int path_index = ik->shared_classpath_index(); 1224 SharedClassPathEntry* ent = 1225 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index); 1226 if (!Universe::is_module_initialized()) { 1227 assert(ent != NULL && ent->is_jrt(), 1228 "Loading non-bootstrap classes before the module system is initialized"); 1229 assert(class_loader.is_null(), "sanity"); 1230 return true; 1231 } 1232 // Get the pkg_entry from the classloader 1233 TempNewSymbol pkg_name = NULL; 1234 PackageEntry* pkg_entry = NULL; 1235 ModuleEntry* mod_entry = NULL; 1236 const char* pkg_string = NULL; 1237 ClassLoaderData* loader_data = class_loader_data(class_loader); 1238 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1239 if (pkg_name != NULL) { 1240 pkg_string = pkg_name->as_C_string(); 1241 if (loader_data != NULL) { 1242 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1243 } 1244 if (pkg_entry != NULL) { 1245 mod_entry = pkg_entry->module(); 1246 } 1247 } 1248 1249 // If the archived class is from a module that has been patched at runtime, 1250 // the class cannot be loaded from the archive. 1251 if (mod_entry != NULL && mod_entry->is_patched()) { 1252 return false; 1253 } 1254 1255 if (class_loader.is_null()) { 1256 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1257 // The NULL classloader can load archived class originated from the 1258 // "modules" jimage and the -Xbootclasspath/a. For class from the 1259 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1260 // by the NULL classloader. 1261 if (mod_entry != NULL) { 1262 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1263 // ModuleEntry's location agrees with the archived class' origination. 1264 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) { 1265 return true; // Module class from the "module" jimage 1266 } 1267 } 1268 1269 // If the archived class is not from the "module" jimage, the class can be 1270 // loaded by the NULL classloader if 1271 // 1272 // 1. the class is from the unamed package 1273 // 2. or, the class is not from a module defined in the NULL classloader 1274 // 3. or, the class is from an unamed module 1275 if (!ent->is_jrt() && ik->is_shared_boot_class()) { 1276 // the class is from the -Xbootclasspath/a 1277 if (pkg_string == NULL || 1278 pkg_entry == NULL || 1279 pkg_entry->in_unnamed_module()) { 1280 assert(mod_entry == NULL || 1281 mod_entry == loader_data->unnamed_module(), 1282 "the unnamed module is not defined in the classloader"); 1283 return true; 1284 } 1285 } 1286 return false; 1287 } else { 1288 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1289 ik, class_loader, pkg_string, pkg_name, 1290 pkg_entry, mod_entry, CHECK_(false)); 1291 return res; 1292 } 1293 } 1294 1295 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1296 Handle class_loader, 1297 Handle protection_domain, TRAPS) { 1298 1299 if (ik != NULL) { 1300 Symbol* class_name = ik->name(); 1301 1302 bool visible = is_shared_class_visible( 1303 class_name, ik, class_loader, CHECK_NULL); 1304 if (!visible) { 1305 return NULL; 1306 } 1307 1308 // Resolve the superclass and interfaces. They must be the same 1309 // as in dump time, because the layout of <ik> depends on 1310 // the specific layout of ik->super() and ik->local_interfaces(). 1311 // 1312 // If unexpected superclass or interfaces are found, we cannot 1313 // load <ik> from the shared archive. 1314 1315 if (ik->super() != NULL) { 1316 Symbol* cn = ik->super()->name(); 1317 Klass *s = resolve_super_or_fail(class_name, cn, 1318 class_loader, protection_domain, true, CHECK_NULL); 1319 if (s != ik->super()) { 1320 // The dynamically resolved super class is not the same as the one we used during dump time, 1321 // so we cannot use ik. 1322 return NULL; 1323 } else { 1324 assert(s->is_shared(), "must be"); 1325 } 1326 } 1327 1328 Array<Klass*>* interfaces = ik->local_interfaces(); 1329 int num_interfaces = interfaces->length(); 1330 for (int index = 0; index < num_interfaces; index++) { 1331 Klass* k = interfaces->at(index); 1332 Symbol* name = k->name(); 1333 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1334 if (k != i) { 1335 // The dynamically resolved interface class is not the same as the one we used during dump time, 1336 // so we cannot use ik. 1337 return NULL; 1338 } else { 1339 assert(i->is_shared(), "must be"); 1340 } 1341 } 1342 1343 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1344 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1345 if (new_ik != NULL) { 1346 // The class is changed by CFLH. Return the new class. The shared class is 1347 // not used. 1348 return new_ik; 1349 } 1350 1351 // Adjust methods to recover missing data. They need addresses for 1352 // interpreter entry points and their default native method address 1353 // must be reset. 1354 1355 // Updating methods must be done under a lock so multiple 1356 // threads don't update these in parallel 1357 // 1358 // Shared classes are all currently loaded by either the bootstrap or 1359 // internal parallel class loaders, so this will never cause a deadlock 1360 // on a custom class loader lock. 1361 1362 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1363 { 1364 HandleMark hm(THREAD); 1365 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1366 check_loader_lock_contention(lockObject, THREAD); 1367 ObjectLocker ol(lockObject, THREAD, true); 1368 // prohibited package check assumes all classes loaded from archive call 1369 // restore_unshareable_info which calls ik->set_package() 1370 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1371 } 1372 1373 ik->print_class_load_logging(loader_data, NULL, NULL); 1374 1375 // For boot loader, ensure that GetSystemPackage knows that a class in this 1376 // package was loaded. 1377 if (class_loader.is_null()) { 1378 int path_index = ik->shared_classpath_index(); 1379 ResourceMark rm; 1380 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1381 } 1382 1383 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1384 // Only dump the classes that can be stored into CDS archive 1385 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1386 ResourceMark rm(THREAD); 1387 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1388 classlist_file->flush(); 1389 } 1390 } 1391 1392 // notify a class loaded from shared object 1393 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1394 } 1395 1396 ik->set_has_passed_fingerprint_check(false); 1397 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1398 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1399 uint64_t cds_fp = ik->get_stored_fingerprint(); 1400 if (aot_fp != 0 && aot_fp == cds_fp) { 1401 // This class matches with a class saved in an AOT library 1402 ik->set_has_passed_fingerprint_check(true); 1403 } else { 1404 ResourceMark rm; 1405 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1406 } 1407 } 1408 return ik; 1409 } 1410 #endif // INCLUDE_CDS 1411 1412 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1413 1414 if (class_loader.is_null()) { 1415 ResourceMark rm; 1416 PackageEntry* pkg_entry = NULL; 1417 bool search_only_bootloader_append = false; 1418 ClassLoaderData *loader_data = class_loader_data(class_loader); 1419 1420 // Find the package in the boot loader's package entry table. 1421 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1422 if (pkg_name != NULL) { 1423 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1424 } 1425 1426 // Prior to attempting to load the class, enforce the boot loader's 1427 // visibility boundaries. 1428 if (!Universe::is_module_initialized()) { 1429 // During bootstrapping, prior to module initialization, any 1430 // class attempting to be loaded must be checked against the 1431 // java.base packages in the boot loader's PackageEntryTable. 1432 // No class outside of java.base is allowed to be loaded during 1433 // this bootstrapping window. 1434 if (!DumpSharedSpaces) { 1435 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1436 // Class is either in the unnamed package or in 1437 // a named package within the unnamed module. Either 1438 // case is outside of java.base, do not attempt to 1439 // load the class post java.base definition. If 1440 // java.base has not been defined, let the class load 1441 // and its package will be checked later by 1442 // ModuleEntryTable::verify_javabase_packages. 1443 if (ModuleEntryTable::javabase_defined()) { 1444 return NULL; 1445 } 1446 } else { 1447 // Check that the class' package is defined within java.base. 1448 ModuleEntry* mod_entry = pkg_entry->module(); 1449 Symbol* mod_entry_name = mod_entry->name(); 1450 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1451 return NULL; 1452 } 1453 } 1454 } 1455 } else { 1456 assert(!DumpSharedSpaces, "Archive dumped after module system initialization"); 1457 // After the module system has been initialized, check if the class' 1458 // package is in a module defined to the boot loader. 1459 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1460 // Class is either in the unnamed package, in a named package 1461 // within a module not defined to the boot loader or in a 1462 // a named package within the unnamed module. In all cases, 1463 // limit visibility to search for the class only in the boot 1464 // loader's append path. 1465 search_only_bootloader_append = true; 1466 } 1467 } 1468 1469 // Prior to bootstrapping's module initialization, never load a class outside 1470 // of the boot loader's module path 1471 assert(Universe::is_module_initialized() || DumpSharedSpaces || 1472 !search_only_bootloader_append, 1473 "Attempt to load a class outside of boot loader's module path"); 1474 1475 // Search the shared system dictionary for classes preloaded into the 1476 // shared spaces. 1477 InstanceKlass* k = NULL; 1478 { 1479 #if INCLUDE_CDS 1480 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1481 k = load_shared_class(class_name, class_loader, THREAD); 1482 #endif 1483 } 1484 1485 if (k == NULL) { 1486 // Use VM class loader 1487 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1488 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1489 } 1490 1491 // find_or_define_instance_class may return a different InstanceKlass 1492 if (k != NULL) { 1493 InstanceKlass* defined_k = 1494 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1495 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1496 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1497 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1498 loader_data->add_to_deallocate_list(k); 1499 k = defined_k; 1500 } else if (HAS_PENDING_EXCEPTION) { 1501 loader_data->add_to_deallocate_list(k); 1502 return NULL; 1503 } 1504 } 1505 return k; 1506 } else { 1507 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1508 ResourceMark rm(THREAD); 1509 1510 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1511 JavaThread* jt = (JavaThread*) THREAD; 1512 1513 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1514 ClassLoader::perf_app_classload_selftime(), 1515 ClassLoader::perf_app_classload_count(), 1516 jt->get_thread_stat()->perf_recursion_counts_addr(), 1517 jt->get_thread_stat()->perf_timers_addr(), 1518 PerfClassTraceTime::CLASS_LOAD); 1519 1520 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1521 // Translate to external class name format, i.e., convert '/' chars to '.' 1522 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1523 1524 JavaValue result(T_OBJECT); 1525 1526 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1527 1528 // Call public unsynchronized loadClass(String) directly for all class loaders 1529 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1530 // acquire a class-name based lock rather than the class loader object lock. 1531 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1532 // so the call to loadClassInternal() was not required. 1533 // 1534 // UnsyncloadClass flag means both call loadClass(String) and do 1535 // not acquire the class loader lock even for class loaders that are 1536 // not parallelCapable. This was a risky transitional 1537 // flag for diagnostic purposes only. It is risky to call 1538 // custom class loaders without synchronization. 1539 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1540 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1541 // Do NOT assume this will be supported in future releases. 1542 // 1543 // Added MustCallLoadClassInternal in case we discover in the field 1544 // a customer that counts on this call 1545 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1546 JavaCalls::call_special(&result, 1547 class_loader, 1548 spec_klass, 1549 vmSymbols::loadClassInternal_name(), 1550 vmSymbols::string_class_signature(), 1551 string, 1552 CHECK_NULL); 1553 } else { 1554 JavaCalls::call_virtual(&result, 1555 class_loader, 1556 spec_klass, 1557 vmSymbols::loadClass_name(), 1558 vmSymbols::string_class_signature(), 1559 string, 1560 CHECK_NULL); 1561 } 1562 1563 assert(result.get_type() == T_OBJECT, "just checking"); 1564 oop obj = (oop) result.get_jobject(); 1565 1566 // Primitive classes return null since forName() can not be 1567 // used to obtain any of the Class objects representing primitives or void 1568 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1569 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1570 // For user defined Java class loaders, check that the name returned is 1571 // the same as that requested. This check is done for the bootstrap 1572 // loader when parsing the class file. 1573 if (class_name == k->name()) { 1574 return k; 1575 } 1576 } 1577 // Class is not found or has the wrong name, return NULL 1578 return NULL; 1579 } 1580 } 1581 1582 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1583 1584 HandleMark hm(THREAD); 1585 ClassLoaderData* loader_data = k->class_loader_data(); 1586 Handle class_loader_h(THREAD, loader_data->class_loader()); 1587 1588 // for bootstrap and other parallel classloaders don't acquire lock, 1589 // use placeholder token 1590 // If a parallelCapable class loader calls define_instance_class instead of 1591 // find_or_define_instance_class to get here, we have a timing 1592 // hole with systemDictionary updates and check_constraints 1593 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1594 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1595 compute_loader_lock_object(class_loader_h, THREAD)), 1596 "define called without lock"); 1597 } 1598 1599 // Check class-loading constraints. Throw exception if violation is detected. 1600 // Grabs and releases SystemDictionary_lock 1601 // The check_constraints/find_class call and update_dictionary sequence 1602 // must be "atomic" for a specific class/classloader pair so we never 1603 // define two different instanceKlasses for that class/classloader pair. 1604 // Existing classloaders will call define_instance_class with the 1605 // classloader lock held 1606 // Parallel classloaders will call find_or_define_instance_class 1607 // which will require a token to perform the define class 1608 Symbol* name_h = k->name(); 1609 Dictionary* dictionary = loader_data->dictionary(); 1610 unsigned int d_hash = dictionary->compute_hash(name_h); 1611 int d_index = dictionary->hash_to_index(d_hash); 1612 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1613 1614 // Register class just loaded with class loader (placed in Vector) 1615 // Note we do this before updating the dictionary, as this can 1616 // fail with an OutOfMemoryError (if it does, we will *not* put this 1617 // class in the dictionary and will not update the class hierarchy). 1618 // JVMTI FollowReferences needs to find the classes this way. 1619 if (k->class_loader() != NULL) { 1620 methodHandle m(THREAD, Universe::loader_addClass_method()); 1621 JavaValue result(T_VOID); 1622 JavaCallArguments args(class_loader_h); 1623 args.push_oop(Handle(THREAD, k->java_mirror())); 1624 JavaCalls::call(&result, m, &args, CHECK); 1625 } 1626 1627 // Add the new class. We need recompile lock during update of CHA. 1628 { 1629 unsigned int p_hash = placeholders()->compute_hash(name_h); 1630 int p_index = placeholders()->hash_to_index(p_hash); 1631 1632 MutexLocker mu_r(Compile_lock, THREAD); 1633 1634 // Add to class hierarchy, initialize vtables, and do possible 1635 // deoptimizations. 1636 add_to_hierarchy(k, CHECK); // No exception, but can block 1637 1638 // Add to systemDictionary - so other classes can see it. 1639 // Grabs and releases SystemDictionary_lock 1640 update_dictionary(d_index, d_hash, p_index, p_hash, 1641 k, class_loader_h, THREAD); 1642 } 1643 k->eager_initialize(THREAD); 1644 1645 // notify jvmti 1646 if (JvmtiExport::should_post_class_load()) { 1647 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1648 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1649 1650 } 1651 class_define_event(k, loader_data); 1652 } 1653 1654 // Support parallel classloading 1655 // All parallel class loaders, including bootstrap classloader 1656 // lock a placeholder entry for this class/class_loader pair 1657 // to allow parallel defines of different classes for this class loader 1658 // With AllowParallelDefine flag==true, in case they do not synchronize around 1659 // FindLoadedClass/DefineClass, calls, we check for parallel 1660 // loading for them, wait if a defineClass is in progress 1661 // and return the initial requestor's results 1662 // This flag does not apply to the bootstrap classloader. 1663 // With AllowParallelDefine flag==false, call through to define_instance_class 1664 // which will throw LinkageError: duplicate class definition. 1665 // False is the requested default. 1666 // For better performance, the class loaders should synchronize 1667 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1668 // potentially waste time reading and parsing the bytestream. 1669 // Note: VM callers should ensure consistency of k/class_name,class_loader 1670 // Be careful when modifying this code: once you have run 1671 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1672 // you need to find_and_remove it before returning. 1673 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1674 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1675 InstanceKlass* k, TRAPS) { 1676 1677 Symbol* name_h = k->name(); // passed in class_name may be null 1678 ClassLoaderData* loader_data = class_loader_data(class_loader); 1679 Dictionary* dictionary = loader_data->dictionary(); 1680 1681 unsigned int d_hash = dictionary->compute_hash(name_h); 1682 int d_index = dictionary->hash_to_index(d_hash); 1683 1684 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1685 unsigned int p_hash = placeholders()->compute_hash(name_h); 1686 int p_index = placeholders()->hash_to_index(p_hash); 1687 PlaceholderEntry* probe; 1688 1689 { 1690 MutexLocker mu(SystemDictionary_lock, THREAD); 1691 // First check if class already defined 1692 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1693 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary); 1694 if (check != NULL) { 1695 return check; 1696 } 1697 } 1698 1699 // Acquire define token for this class/classloader 1700 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1701 // Wait if another thread defining in parallel 1702 // All threads wait - even those that will throw duplicate class: otherwise 1703 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1704 // if other thread has not finished updating dictionary 1705 while (probe->definer() != NULL) { 1706 SystemDictionary_lock->wait(); 1707 } 1708 // Only special cases allow parallel defines and can use other thread's results 1709 // Other cases fall through, and may run into duplicate defines 1710 // caught by finding an entry in the SystemDictionary 1711 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1712 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1713 SystemDictionary_lock->notify_all(); 1714 #ifdef ASSERT 1715 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary); 1716 assert(check != NULL, "definer missed recording success"); 1717 #endif 1718 return probe->instance_klass(); 1719 } else { 1720 // This thread will define the class (even if earlier thread tried and had an error) 1721 probe->set_definer(THREAD); 1722 } 1723 } 1724 1725 define_instance_class(k, THREAD); 1726 1727 Handle linkage_exception = Handle(); // null handle 1728 1729 // definer must notify any waiting threads 1730 { 1731 MutexLocker mu(SystemDictionary_lock, THREAD); 1732 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1733 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1734 if (probe != NULL) { 1735 if (HAS_PENDING_EXCEPTION) { 1736 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1737 CLEAR_PENDING_EXCEPTION; 1738 } else { 1739 probe->set_instance_klass(k); 1740 } 1741 probe->set_definer(NULL); 1742 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1743 SystemDictionary_lock->notify_all(); 1744 } 1745 } 1746 1747 // Can't throw exception while holding lock due to rank ordering 1748 if (linkage_exception() != NULL) { 1749 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1750 } 1751 1752 return k; 1753 } 1754 1755 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1756 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1757 if (class_loader.is_null()) { 1758 return Handle(THREAD, _system_loader_lock_obj); 1759 } else { 1760 return class_loader; 1761 } 1762 } 1763 1764 // This method is added to check how often we have to wait to grab loader 1765 // lock. The results are being recorded in the performance counters defined in 1766 // ClassLoader::_sync_systemLoaderLockContentionRate and 1767 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1768 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1769 if (!UsePerfData) { 1770 return; 1771 } 1772 1773 assert(!loader_lock.is_null(), "NULL lock object"); 1774 1775 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1776 == ObjectSynchronizer::owner_other) { 1777 // contention will likely happen, so increment the corresponding 1778 // contention counter. 1779 if (loader_lock() == _system_loader_lock_obj) { 1780 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1781 } else { 1782 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1783 } 1784 } 1785 } 1786 1787 // ---------------------------------------------------------------------------- 1788 // Lookup 1789 1790 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash, 1791 Symbol* class_name, 1792 Dictionary* dictionary) { 1793 assert_locked_or_safepoint(SystemDictionary_lock); 1794 return dictionary->find_class(index, hash, class_name); 1795 } 1796 1797 1798 // Basic find on classes in the midst of being loaded 1799 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1800 ClassLoaderData* loader_data) { 1801 assert_locked_or_safepoint(SystemDictionary_lock); 1802 unsigned int p_hash = placeholders()->compute_hash(class_name); 1803 int p_index = placeholders()->hash_to_index(p_hash); 1804 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1805 } 1806 1807 1808 // Used for assertions and verification only 1809 // Precalculating the hash and index is an optimization because there are many lookups 1810 // before adding the class. 1811 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1812 assert_locked_or_safepoint(SystemDictionary_lock); 1813 #ifndef ASSERT 1814 guarantee(VerifyBeforeGC || 1815 VerifyDuringGC || 1816 VerifyBeforeExit || 1817 VerifyDuringStartup || 1818 VerifyAfterGC, "too expensive"); 1819 #endif 1820 1821 Dictionary* dictionary = loader_data->dictionary_or_null(); 1822 if (dictionary == NULL) { 1823 return NULL; 1824 } 1825 unsigned int d_hash = dictionary->compute_hash(class_name); 1826 int d_index = dictionary->hash_to_index(d_hash); 1827 return find_class(d_index, d_hash, class_name, dictionary); 1828 } 1829 1830 1831 // ---------------------------------------------------------------------------- 1832 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1833 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1834 // before a new class is used. 1835 1836 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1837 assert(k != NULL, "just checking"); 1838 assert_locked_or_safepoint(Compile_lock); 1839 1840 // Link into hierachy. Make sure the vtables are initialized before linking into 1841 k->append_to_sibling_list(); // add to superklass/sibling list 1842 k->process_interfaces(THREAD); // handle all "implements" declarations 1843 k->set_init_state(InstanceKlass::loaded); 1844 // Now flush all code that depended on old class hierarchy. 1845 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1846 // Also, first reinitialize vtable because it may have gotten out of synch 1847 // while the new class wasn't connected to the class hierarchy. 1848 CodeCache::flush_dependents_on(k); 1849 } 1850 1851 // ---------------------------------------------------------------------------- 1852 // GC support 1853 1854 // Following roots during mark-sweep is separated in two phases. 1855 // 1856 // The first phase follows preloaded classes and all other system 1857 // classes, since these will never get unloaded anyway. 1858 // 1859 // The second phase removes (unloads) unreachable classes from the 1860 // system dictionary and follows the remaining classes' contents. 1861 1862 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1863 roots_oops_do(blk, NULL); 1864 } 1865 1866 1867 #ifdef ASSERT 1868 class VerifySDReachableAndLiveClosure : public OopClosure { 1869 private: 1870 BoolObjectClosure* _is_alive; 1871 1872 template <class T> void do_oop_work(T* p) { 1873 oop obj = oopDesc::load_decode_heap_oop(p); 1874 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); 1875 } 1876 1877 public: 1878 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1879 1880 virtual void do_oop(oop* p) { do_oop_work(p); } 1881 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1882 }; 1883 #endif 1884 1885 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1886 // Note: anonymous classes are not in the SD. 1887 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, 1888 GCTimer* gc_timer, 1889 bool do_cleaning) { 1890 1891 1892 bool unloading_occurred; 1893 { 1894 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1895 1896 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1897 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, 1898 do_cleaning); 1899 } 1900 1901 if (unloading_occurred) { 1902 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1903 constraints()->purge_loader_constraints(); 1904 resolution_errors()->purge_resolution_errors(); 1905 } 1906 1907 { 1908 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1909 // Oops referenced by the system dictionary may get unreachable independently 1910 // of the class loader (eg. cached protection domain oops). So we need to 1911 // explicitly unlink them here. 1912 _pd_cache_table->unlink(is_alive); 1913 1914 #ifdef ASSERT 1915 VerifySDReachableAndLiveClosure cl(is_alive); 1916 _pd_cache_table->oops_do(&cl); 1917 #endif 1918 } 1919 1920 if (do_cleaning) { 1921 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1922 ResolvedMethodTable::unlink(is_alive); 1923 } 1924 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 // Do strong roots marking if the closures are the same. 1935 if (strong == weak || !ClassUnloading) { 1936 // Only the protection domain oops contain references into the heap. Iterate 1937 // over all of them. 1938 _pd_cache_table->oops_do(strong); 1939 } else { 1940 if (weak != NULL) { 1941 _pd_cache_table->oops_do(weak); 1942 } 1943 } 1944 1945 // Visit extra methods 1946 invoke_method_table()->oops_do(strong); 1947 1948 if (weak != NULL) { 1949 ResolvedMethodTable::oops_do(weak); 1950 } 1951 } 1952 1953 void SystemDictionary::oops_do(OopClosure* f) { 1954 f->do_oop(&_java_system_loader); 1955 f->do_oop(&_system_loader_lock_obj); 1956 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1957 1958 // Only the protection domain oops contain references into the heap. Iterate 1959 // over all of them. 1960 _pd_cache_table->oops_do(f); 1961 1962 // Visit extra methods 1963 invoke_method_table()->oops_do(f); 1964 1965 ResolvedMethodTable::oops_do(f); 1966 } 1967 1968 void SystemDictionary::methods_do(void f(Method*)) { 1969 // Walk methods in loaded classes 1970 ClassLoaderDataGraph::methods_do(f); 1971 // Walk method handle intrinsics 1972 invoke_method_table()->methods_do(f); 1973 } 1974 1975 void SystemDictionary::remove_classes_in_error_state() { 1976 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 1977 } 1978 1979 // ---------------------------------------------------------------------------- 1980 // Lazily load klasses 1981 1982 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1983 // if multiple threads calling this function, only one thread will load 1984 // the class. The other threads will find the loaded version once the 1985 // class is loaded. 1986 Klass* aos = _abstract_ownable_synchronizer_klass; 1987 if (aos == NULL) { 1988 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1989 // Force a fence to prevent any read before the write completes 1990 OrderAccess::fence(); 1991 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); 1992 } 1993 } 1994 1995 // ---------------------------------------------------------------------------- 1996 // Initialization 1997 1998 void SystemDictionary::initialize(TRAPS) { 1999 // Allocate arrays 2000 _placeholders = new PlaceholderTable(_placeholder_table_size); 2001 _number_of_modifications = 0; 2002 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 2003 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 2004 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 2005 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 2006 2007 // Allocate private object used as system class loader lock 2008 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 2009 // Initialize basic classes 2010 initialize_preloaded_classes(CHECK); 2011 } 2012 2013 // Compact table of directions on the initialization of klasses: 2014 static const short wk_init_info[] = { 2015 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 2016 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 2017 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 2018 | (int)SystemDictionary::option ), 2019 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 2020 #undef WK_KLASS_INIT_INFO 2021 0 2022 }; 2023 2024 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 2025 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2026 int info = wk_init_info[id - FIRST_WKID]; 2027 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2028 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 2029 InstanceKlass** klassp = &_well_known_klasses[id]; 2030 2031 bool must_load; 2032 #if INCLUDE_JVMCI 2033 if (EnableJVMCI) { 2034 // If JVMCI is enabled we require its classes to be found. 2035 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 2036 } else 2037 #endif 2038 { 2039 must_load = (init_opt < SystemDictionary::Opt); 2040 } 2041 2042 if ((*klassp) == NULL) { 2043 Klass* k; 2044 if (must_load) { 2045 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 2046 } else { 2047 k = resolve_or_null(symbol, CHECK_0); // load optional klass 2048 } 2049 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 2050 } 2051 return ((*klassp) != NULL); 2052 } 2053 2054 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 2055 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 2056 for (int id = (int)start_id; id < (int)limit_id; id++) { 2057 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2058 int info = wk_init_info[id - FIRST_WKID]; 2059 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2060 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 2061 2062 initialize_wk_klass((WKID)id, opt, CHECK); 2063 } 2064 2065 // move the starting value forward to the limit: 2066 start_id = limit_id; 2067 } 2068 2069 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 2070 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 2071 2072 // Create the ModuleEntry for java.base. This call needs to be done here, 2073 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 2074 ClassLoader::classLoader_init2(CHECK); 2075 2076 // Preload commonly used klasses 2077 WKID scan = FIRST_WKID; 2078 // first do Object, then String, Class 2079 if (UseSharedSpaces) { 2080 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2081 // Initialize the constant pool for the Object_class 2082 Object_klass()->constants()->restore_unshareable_info(CHECK); 2083 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2084 } else { 2085 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2086 } 2087 2088 // Calculate offsets for String and Class classes since they are loaded and 2089 // can be used after this point. 2090 java_lang_String::compute_offsets(); 2091 java_lang_Class::compute_offsets(); 2092 2093 // Fixup mirrors for classes loaded before java.lang.Class. 2094 // These calls iterate over the objects currently in the perm gen 2095 // so calling them at this point is matters (not before when there 2096 // are fewer objects and not later after there are more objects 2097 // in the perm gen. 2098 Universe::initialize_basic_type_mirrors(CHECK); 2099 Universe::fixup_mirrors(CHECK); 2100 2101 // do a bunch more: 2102 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2103 2104 // Preload ref klasses and set reference types 2105 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2106 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2107 2108 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2109 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2110 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2111 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2112 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2113 2114 // JSR 292 classes 2115 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2116 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2117 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 2118 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 2119 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); 2120 2121 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2122 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2123 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2124 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2125 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2126 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2127 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2128 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2129 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2130 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2131 2132 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 2133 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 2134 _has_loadClassInternal = (method != NULL); 2135 } 2136 { // Compute whether we should use checkPackageAccess or NOT 2137 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2138 _has_checkPackageAccess = (method != NULL); 2139 } 2140 } 2141 2142 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2143 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2144 BasicType SystemDictionary::box_klass_type(Klass* k) { 2145 assert(k != NULL, ""); 2146 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2147 if (_box_klasses[i] == k) 2148 return (BasicType)i; 2149 } 2150 return T_OBJECT; 2151 } 2152 2153 // Constraints on class loaders. The details of the algorithm can be 2154 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2155 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2156 // that the system dictionary needs to maintain a set of contraints that 2157 // must be satisfied by all classes in the dictionary. 2158 // if defining is true, then LinkageError if already in systemDictionary 2159 // if initiating loader, then ok if InstanceKlass matches existing entry 2160 2161 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 2162 InstanceKlass* k, 2163 Handle class_loader, bool defining, 2164 TRAPS) { 2165 const char *linkage_error1 = NULL; 2166 const char *linkage_error2 = NULL; 2167 { 2168 Symbol* name = k->name(); 2169 ClassLoaderData *loader_data = class_loader_data(class_loader); 2170 2171 MutexLocker mu(SystemDictionary_lock, THREAD); 2172 2173 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary()); 2174 if (check != NULL) { 2175 // if different InstanceKlass - duplicate class definition, 2176 // else - ok, class loaded by a different thread in parallel, 2177 // we should only have found it if it was done loading and ok to use 2178 // system dictionary only holds instance classes, placeholders 2179 // also holds array classes 2180 2181 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2182 if ((defining == true) || (k != check)) { 2183 linkage_error1 = "loader (instance of "; 2184 linkage_error2 = "): attempted duplicate class definition for name: \""; 2185 } else { 2186 return; 2187 } 2188 } 2189 2190 #ifdef ASSERT 2191 Symbol* ph_check = find_placeholder(name, loader_data); 2192 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2193 #endif 2194 2195 if (linkage_error1 == NULL) { 2196 if (constraints()->check_or_update(k, class_loader, name) == false) { 2197 linkage_error1 = "loader constraint violation: loader (instance of "; 2198 linkage_error2 = ") previously initiated loading for a different type with name \""; 2199 } 2200 } 2201 } 2202 2203 // Throw error now if needed (cannot throw while holding 2204 // SystemDictionary_lock because of rank ordering) 2205 2206 if (linkage_error1) { 2207 ResourceMark rm(THREAD); 2208 const char* class_loader_name = loader_name(class_loader()); 2209 char* type_name = k->name()->as_C_string(); 2210 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) + 2211 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte. 2212 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2213 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name); 2214 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2215 } 2216 } 2217 2218 2219 // Update system dictionary - done after check_constraint and add_to_hierachy 2220 // have been called. 2221 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 2222 int p_index, unsigned int p_hash, 2223 InstanceKlass* k, 2224 Handle class_loader, 2225 TRAPS) { 2226 // Compile_lock prevents systemDictionary updates during compilations 2227 assert_locked_or_safepoint(Compile_lock); 2228 Symbol* name = k->name(); 2229 ClassLoaderData *loader_data = class_loader_data(class_loader); 2230 2231 { 2232 MutexLocker mu1(SystemDictionary_lock, THREAD); 2233 2234 // See whether biased locking is enabled and if so set it for this 2235 // klass. 2236 // Note that this must be done past the last potential blocking 2237 // point / safepoint. We enable biased locking lazily using a 2238 // VM_Operation to iterate the SystemDictionary and installing the 2239 // biasable mark word into each InstanceKlass's prototype header. 2240 // To avoid race conditions where we accidentally miss enabling the 2241 // optimization for one class in the process of being added to the 2242 // dictionary, we must not safepoint after the test of 2243 // BiasedLocking::enabled(). 2244 if (UseBiasedLocking && BiasedLocking::enabled()) { 2245 // Set biased locking bit for all loaded classes; it will be 2246 // cleared if revocation occurs too often for this type 2247 // NOTE that we must only do this when the class is initally 2248 // defined, not each time it is referenced from a new class loader 2249 if (k->class_loader() == class_loader()) { 2250 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2251 } 2252 } 2253 2254 // Make a new system dictionary entry. 2255 Dictionary* dictionary = loader_data->dictionary(); 2256 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary); 2257 if (sd_check == NULL) { 2258 dictionary->add_klass(d_index, d_hash, name, k); 2259 notice_modification(); 2260 } 2261 #ifdef ASSERT 2262 sd_check = find_class(d_index, d_hash, name, dictionary); 2263 assert (sd_check != NULL, "should have entry in system dictionary"); 2264 // Note: there may be a placeholder entry: for circularity testing 2265 // or for parallel defines 2266 #endif 2267 SystemDictionary_lock->notify_all(); 2268 } 2269 } 2270 2271 2272 // Try to find a class name using the loader constraints. The 2273 // loader constraints might know about a class that isn't fully loaded 2274 // yet and these will be ignored. 2275 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2276 Symbol* class_name, Handle class_loader, TRAPS) { 2277 2278 // First see if it has been loaded directly. 2279 // Force the protection domain to be null. (This removes protection checks.) 2280 Handle no_protection_domain; 2281 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2282 no_protection_domain, CHECK_NULL); 2283 if (klass != NULL) 2284 return klass; 2285 2286 // Now look to see if it has been loaded elsewhere, and is subject to 2287 // a loader constraint that would require this loader to return the 2288 // klass that is already loaded. 2289 if (FieldType::is_array(class_name)) { 2290 // For array classes, their Klass*s are not kept in the 2291 // constraint table. The element Klass*s are. 2292 FieldArrayInfo fd; 2293 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2294 if (t != T_OBJECT) { 2295 klass = Universe::typeArrayKlassObj(t); 2296 } else { 2297 MutexLocker mu(SystemDictionary_lock, THREAD); 2298 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2299 } 2300 // If element class already loaded, allocate array klass 2301 if (klass != NULL) { 2302 klass = klass->array_klass_or_null(fd.dimension()); 2303 } 2304 } else { 2305 MutexLocker mu(SystemDictionary_lock, THREAD); 2306 // Non-array classes are easy: simply check the constraint table. 2307 klass = constraints()->find_constrained_klass(class_name, class_loader); 2308 } 2309 2310 return klass; 2311 } 2312 2313 2314 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2315 Handle class_loader1, 2316 Handle class_loader2, 2317 Thread* THREAD) { 2318 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2319 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2320 2321 Symbol* constraint_name = NULL; 2322 if (!FieldType::is_array(class_name)) { 2323 constraint_name = class_name; 2324 } else { 2325 // For array classes, their Klass*s are not kept in the 2326 // constraint table. The element classes are. 2327 FieldArrayInfo fd; 2328 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2329 // primitive types always pass 2330 if (t != T_OBJECT) { 2331 return true; 2332 } else { 2333 constraint_name = fd.object_key(); 2334 } 2335 } 2336 2337 Dictionary* dictionary1 = loader_data1->dictionary(); 2338 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2339 int d_index1 = dictionary1->hash_to_index(d_hash1); 2340 2341 Dictionary* dictionary2 = loader_data2->dictionary(); 2342 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2343 int d_index2 = dictionary2->hash_to_index(d_hash2); 2344 2345 { 2346 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2347 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1); 2348 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2); 2349 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2350 klass2, class_loader2); 2351 } 2352 } 2353 2354 // Add entry to resolution error table to record the error when the first 2355 // attempt to resolve a reference to a class has failed. 2356 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2357 Symbol* error, Symbol* message) { 2358 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2359 int index = resolution_errors()->hash_to_index(hash); 2360 { 2361 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2362 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2363 } 2364 } 2365 2366 // Delete a resolution error for RedefineClasses for a constant pool is going away 2367 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2368 resolution_errors()->delete_entry(pool); 2369 } 2370 2371 // Lookup resolution error table. Returns error if found, otherwise NULL. 2372 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2373 Symbol** message) { 2374 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2375 int index = resolution_errors()->hash_to_index(hash); 2376 { 2377 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2378 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2379 if (entry != NULL) { 2380 *message = entry->message(); 2381 return entry->error(); 2382 } else { 2383 return NULL; 2384 } 2385 } 2386 } 2387 2388 2389 // Signature constraints ensure that callers and callees agree about 2390 // the meaning of type names in their signatures. This routine is the 2391 // intake for constraints. It collects them from several places: 2392 // 2393 // * LinkResolver::resolve_method (if check_access is true) requires 2394 // that the resolving class (the caller) and the defining class of 2395 // the resolved method (the callee) agree on each type in the 2396 // method's signature. 2397 // 2398 // * LinkResolver::resolve_interface_method performs exactly the same 2399 // checks. 2400 // 2401 // * LinkResolver::resolve_field requires that the constant pool 2402 // attempting to link to a field agree with the field's defining 2403 // class about the type of the field signature. 2404 // 2405 // * klassVtable::initialize_vtable requires that, when a class 2406 // overrides a vtable entry allocated by a superclass, that the 2407 // overriding method (i.e., the callee) agree with the superclass 2408 // on each type in the method's signature. 2409 // 2410 // * klassItable::initialize_itable requires that, when a class fills 2411 // in its itables, for each non-abstract method installed in an 2412 // itable, the method (i.e., the callee) agree with the interface 2413 // on each type in the method's signature. 2414 // 2415 // All those methods have a boolean (check_access, checkconstraints) 2416 // which turns off the checks. This is used from specialized contexts 2417 // such as bootstrapping, dumping, and debugging. 2418 // 2419 // No direct constraint is placed between the class and its 2420 // supertypes. Constraints are only placed along linked relations 2421 // between callers and callees. When a method overrides or implements 2422 // an abstract method in a supertype (superclass or interface), the 2423 // constraints are placed as if the supertype were the caller to the 2424 // overriding method. (This works well, since callers to the 2425 // supertype have already established agreement between themselves and 2426 // the supertype.) As a result of all this, a class can disagree with 2427 // its supertype about the meaning of a type name, as long as that 2428 // class neither calls a relevant method of the supertype, nor is 2429 // called (perhaps via an override) from the supertype. 2430 // 2431 // 2432 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2433 // 2434 // Make sure all class components (including arrays) in the given 2435 // signature will be resolved to the same class in both loaders. 2436 // Returns the name of the type that failed a loader constraint check, or 2437 // NULL if no constraint failed. No exception except OOME is thrown. 2438 // Arrays are not added to the loader constraint table, their elements are. 2439 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2440 Handle loader1, Handle loader2, 2441 bool is_method, TRAPS) { 2442 // Nothing to do if loaders are the same. 2443 if (loader1() == loader2()) { 2444 return NULL; 2445 } 2446 2447 SignatureStream sig_strm(signature, is_method); 2448 while (!sig_strm.is_done()) { 2449 if (sig_strm.is_object()) { 2450 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2451 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2452 return sig; 2453 } 2454 } 2455 sig_strm.next(); 2456 } 2457 return NULL; 2458 } 2459 2460 2461 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2462 Symbol* signature, 2463 TRAPS) { 2464 methodHandle empty; 2465 assert(MethodHandles::is_signature_polymorphic(iid) && 2466 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2467 iid != vmIntrinsics::_invokeGeneric, 2468 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2469 2470 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2471 int index = invoke_method_table()->hash_to_index(hash); 2472 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2473 methodHandle m; 2474 if (spe == NULL || spe->method() == NULL) { 2475 spe = NULL; 2476 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2477 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2478 if (!Arguments::is_interpreter_only()) { 2479 // Generate a compiled form of the MH intrinsic. 2480 AdapterHandlerLibrary::create_native_wrapper(m); 2481 // Check if have the compiled code. 2482 if (!m->has_compiled_code()) { 2483 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2484 "Out of space in CodeCache for method handle intrinsic", empty); 2485 } 2486 } 2487 // Now grab the lock. We might have to throw away the new method, 2488 // if a racing thread has managed to install one at the same time. 2489 { 2490 MutexLocker ml(SystemDictionary_lock, THREAD); 2491 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2492 if (spe == NULL) 2493 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2494 if (spe->method() == NULL) 2495 spe->set_method(m()); 2496 } 2497 } 2498 2499 assert(spe != NULL && spe->method() != NULL, ""); 2500 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2501 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2502 "MH intrinsic invariant"); 2503 return spe->method(); 2504 } 2505 2506 // Helper for unpacking the return value from linkMethod and linkCallSite. 2507 static methodHandle unpack_method_and_appendix(Handle mname, 2508 Klass* accessing_klass, 2509 objArrayHandle appendix_box, 2510 Handle* appendix_result, 2511 TRAPS) { 2512 methodHandle empty; 2513 if (mname.not_null()) { 2514 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2515 if (m != NULL) { 2516 oop appendix = appendix_box->obj_at(0); 2517 if (TraceMethodHandles) { 2518 #ifndef PRODUCT 2519 ttyLocker ttyl; 2520 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2521 m->print(); 2522 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2523 tty->cr(); 2524 #endif //PRODUCT 2525 } 2526 (*appendix_result) = Handle(THREAD, appendix); 2527 // the target is stored in the cpCache and if a reference to this 2528 // MethodName is dropped we need a way to make sure the 2529 // class_loader containing this method is kept alive. 2530 // FIXME: the appendix might also preserve this dependency. 2531 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2532 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2533 return methodHandle(THREAD, m); 2534 } 2535 } 2536 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2537 return empty; 2538 } 2539 2540 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2541 Symbol* name, 2542 Symbol* signature, 2543 Klass* accessing_klass, 2544 Handle *appendix_result, 2545 Handle *method_type_result, 2546 TRAPS) { 2547 methodHandle empty; 2548 assert(THREAD->can_call_java() ,""); 2549 Handle method_type = 2550 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2551 2552 int ref_kind = JVM_REF_invokeVirtual; 2553 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2554 Handle name_str (THREAD, name_oop); 2555 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2556 assert(appendix_box->obj_at(0) == NULL, ""); 2557 2558 // This should not happen. JDK code should take care of that. 2559 if (accessing_klass == NULL || method_type.is_null()) { 2560 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2561 } 2562 2563 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2564 JavaCallArguments args; 2565 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2566 args.push_int(ref_kind); 2567 args.push_oop(Handle(THREAD, klass->java_mirror())); 2568 args.push_oop(name_str); 2569 args.push_oop(method_type); 2570 args.push_oop(appendix_box); 2571 JavaValue result(T_OBJECT); 2572 JavaCalls::call_static(&result, 2573 SystemDictionary::MethodHandleNatives_klass(), 2574 vmSymbols::linkMethod_name(), 2575 vmSymbols::linkMethod_signature(), 2576 &args, CHECK_(empty)); 2577 Handle mname(THREAD, (oop) result.get_jobject()); 2578 (*method_type_result) = method_type; 2579 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2580 } 2581 2582 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2583 // We must ensure that all class loaders everywhere will reach this class, for any client. 2584 // This is a safe bet for public classes in java.lang, such as Object and String. 2585 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2586 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2587 static bool is_always_visible_class(oop mirror) { 2588 Klass* klass = java_lang_Class::as_Klass(mirror); 2589 if (klass->is_objArray_klass()) { 2590 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2591 } 2592 if (klass->is_typeArray_klass()) { 2593 return true; // primitive array 2594 } 2595 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2596 return klass->is_public() && 2597 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2598 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2599 } 2600 2601 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2602 // signature, as interpreted relative to the given class loader. 2603 // Because of class loader constraints, all method handle usage must be 2604 // consistent with this loader. 2605 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2606 Klass* accessing_klass, 2607 TRAPS) { 2608 Handle empty; 2609 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2610 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2611 int index = invoke_method_table()->hash_to_index(hash); 2612 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2613 if (spe != NULL && spe->method_type() != NULL) { 2614 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2615 return Handle(THREAD, spe->method_type()); 2616 } else if (!THREAD->can_call_java()) { 2617 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2618 return Handle(); // do not attempt from within compiler, unless it was cached 2619 } 2620 2621 Handle class_loader, protection_domain; 2622 if (accessing_klass != NULL) { 2623 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2624 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2625 } 2626 bool can_be_cached = true; 2627 int npts = ArgumentCount(signature).size(); 2628 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2629 int arg = 0; 2630 Handle rt; // the return type from the signature 2631 ResourceMark rm(THREAD); 2632 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2633 oop mirror = NULL; 2634 if (can_be_cached) { 2635 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2636 mirror = ss.as_java_mirror(Handle(), Handle(), 2637 SignatureStream::ReturnNull, CHECK_(empty)); 2638 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2639 // Fall back to accessing_klass context. 2640 can_be_cached = false; 2641 } 2642 } 2643 if (!can_be_cached) { 2644 // Resolve, throwing a real error if it doesn't work. 2645 mirror = ss.as_java_mirror(class_loader, protection_domain, 2646 SignatureStream::NCDFError, CHECK_(empty)); 2647 } 2648 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string()); 2649 if (ss.at_return_type()) 2650 rt = Handle(THREAD, mirror); 2651 else 2652 pts->obj_at_put(arg++, mirror); 2653 2654 // Check accessibility. 2655 if (ss.is_object() && accessing_klass != NULL) { 2656 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2657 mirror = NULL; // safety 2658 // Emulate ConstantPool::verify_constant_pool_resolve. 2659 if (sel_klass->is_objArray_klass()) 2660 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2661 if (sel_klass->is_instance_klass()) { 2662 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty)); 2663 } 2664 } 2665 } 2666 assert(arg == npts, ""); 2667 2668 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2669 JavaCallArguments args(Handle(THREAD, rt())); 2670 args.push_oop(pts); 2671 JavaValue result(T_OBJECT); 2672 JavaCalls::call_static(&result, 2673 SystemDictionary::MethodHandleNatives_klass(), 2674 vmSymbols::findMethodHandleType_name(), 2675 vmSymbols::findMethodHandleType_signature(), 2676 &args, CHECK_(empty)); 2677 Handle method_type(THREAD, (oop) result.get_jobject()); 2678 2679 if (can_be_cached) { 2680 // We can cache this MethodType inside the JVM. 2681 MutexLocker ml(SystemDictionary_lock, THREAD); 2682 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2683 if (spe == NULL) 2684 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2685 if (spe->method_type() == NULL) { 2686 spe->set_method_type(method_type()); 2687 } 2688 } 2689 2690 // report back to the caller with the MethodType 2691 return method_type; 2692 } 2693 2694 // Ask Java code to find or construct a method handle constant. 2695 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2696 int ref_kind, //e.g., JVM_REF_invokeVirtual 2697 Klass* callee, 2698 Symbol* name_sym, 2699 Symbol* signature, 2700 TRAPS) { 2701 Handle empty; 2702 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2703 Handle type; 2704 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2705 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2706 } else if (caller == NULL) { 2707 // This should not happen. JDK code should take care of that. 2708 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2709 } else { 2710 ResourceMark rm(THREAD); 2711 SignatureStream ss(signature, false); 2712 if (!ss.is_done()) { 2713 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()), 2714 Handle(THREAD, caller->protection_domain()), 2715 SignatureStream::NCDFError, CHECK_(empty)); 2716 type = Handle(THREAD, mirror); 2717 ss.next(); 2718 if (!ss.is_done()) type = Handle(); // error! 2719 } 2720 } 2721 if (type.is_null()) { 2722 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2723 } 2724 2725 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2726 JavaCallArguments args; 2727 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2728 args.push_int(ref_kind); 2729 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2730 args.push_oop(name); 2731 args.push_oop(type); 2732 JavaValue result(T_OBJECT); 2733 JavaCalls::call_static(&result, 2734 SystemDictionary::MethodHandleNatives_klass(), 2735 vmSymbols::linkMethodHandleConstant_name(), 2736 vmSymbols::linkMethodHandleConstant_signature(), 2737 &args, CHECK_(empty)); 2738 return Handle(THREAD, (oop) result.get_jobject()); 2739 } 2740 2741 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2742 // name and signature, as interpreted relative to the given class loader. 2743 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2744 Handle bootstrap_specifier, 2745 Symbol* name, 2746 Symbol* type, 2747 Handle *appendix_result, 2748 Handle *method_type_result, 2749 TRAPS) { 2750 methodHandle empty; 2751 Handle bsm, info; 2752 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2753 bsm = bootstrap_specifier; 2754 } else { 2755 assert(bootstrap_specifier->is_objArray(), ""); 2756 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2757 int len = args->length(); 2758 assert(len >= 1, ""); 2759 bsm = Handle(THREAD, args->obj_at(0)); 2760 if (len > 1) { 2761 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2762 for (int i = 1; i < len; i++) 2763 args1->obj_at_put(i-1, args->obj_at(i)); 2764 info = Handle(THREAD, args1); 2765 } 2766 } 2767 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2768 "caller must supply a valid BSM"); 2769 2770 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2771 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2772 2773 // This should not happen. JDK code should take care of that. 2774 if (caller == NULL || method_type.is_null()) { 2775 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2776 } 2777 2778 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2779 assert(appendix_box->obj_at(0) == NULL, ""); 2780 2781 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2782 JavaCallArguments args; 2783 args.push_oop(Handle(THREAD, caller->java_mirror())); 2784 args.push_oop(bsm); 2785 args.push_oop(method_name); 2786 args.push_oop(method_type); 2787 args.push_oop(info); 2788 args.push_oop(appendix_box); 2789 JavaValue result(T_OBJECT); 2790 JavaCalls::call_static(&result, 2791 SystemDictionary::MethodHandleNatives_klass(), 2792 vmSymbols::linkCallSite_name(), 2793 vmSymbols::linkCallSite_signature(), 2794 &args, CHECK_(empty)); 2795 Handle mname(THREAD, (oop) result.get_jobject()); 2796 (*method_type_result) = method_type; 2797 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2798 } 2799 2800 // Protection domain cache table handling 2801 2802 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2803 return _pd_cache_table->get(protection_domain); 2804 } 2805 2806 2807 void SystemDictionary::reorder_dictionary() { 2808 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary(); 2809 } 2810 2811 2812 void SystemDictionary::copy_buckets(char** top, char* end) { 2813 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2814 } 2815 2816 2817 void SystemDictionary::copy_table(char** top, char* end) { 2818 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2819 } 2820 2821 // ---------------------------------------------------------------------------- 2822 void SystemDictionary::print_shared(bool details) { 2823 shared_dictionary()->print(details); 2824 } 2825 2826 void SystemDictionary::print(bool details) { 2827 if (shared_dictionary() != NULL) { 2828 tty->print_cr("Shared Dictionary"); 2829 shared_dictionary()->print(details); 2830 } 2831 2832 GCMutexLocker mu(SystemDictionary_lock); 2833 2834 ClassLoaderDataGraph::print_dictionary(details); 2835 2836 // Placeholders 2837 placeholders()->print(); 2838 tty->cr(); 2839 2840 // loader constraints - print under SD_lock 2841 constraints()->print(); 2842 tty->cr(); 2843 2844 _pd_cache_table->print(); 2845 tty->cr(); 2846 } 2847 2848 2849 void SystemDictionary::verify() { 2850 guarantee(constraints() != NULL, 2851 "Verify of loader constraints failed"); 2852 guarantee(placeholders()->number_of_entries() >= 0, 2853 "Verify of system dictionary failed"); 2854 2855 // Verify dictionary 2856 ClassLoaderDataGraph::verify_dictionary(); 2857 2858 GCMutexLocker mu(SystemDictionary_lock); 2859 placeholders()->verify(); 2860 2861 // Verify constraint table 2862 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2863 constraints()->verify(placeholders()); 2864 2865 _pd_cache_table->verify(); 2866 } 2867 2868 // caller needs ResourceMark 2869 const char* SystemDictionary::loader_name(const oop loader) { 2870 return ((loader) == NULL ? "<bootloader>" : 2871 InstanceKlass::cast((loader)->klass())->name()->as_C_string()); 2872 } 2873 2874 // caller needs ResourceMark 2875 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { 2876 return (loader_data->class_loader() == NULL ? "<bootloader>" : 2877 SystemDictionary::loader_name(loader_data->class_loader())); 2878 }