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