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