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