1 /* 2 * Copyright (c) 1997, 2019, 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/classLoaderDataGraph.inline.hpp" 33 #include "classfile/classLoaderExt.hpp" 34 #include "classfile/dictionary.hpp" 35 #include "classfile/javaClasses.inline.hpp" 36 #include "classfile/klassFactory.hpp" 37 #include "classfile/loaderConstraints.hpp" 38 #include "classfile/packageEntry.hpp" 39 #include "classfile/placeholders.hpp" 40 #include "classfile/protectionDomainCache.hpp" 41 #include "classfile/resolutionErrors.hpp" 42 #include "classfile/stringTable.hpp" 43 #include "classfile/systemDictionary.hpp" 44 #include "classfile/vmSymbols.hpp" 45 #include "code/codeCache.hpp" 46 #include "compiler/compileBroker.hpp" 47 #include "gc/shared/gcTraceTime.inline.hpp" 48 #include "gc/shared/oopStorage.inline.hpp" 49 #include "interpreter/bytecodeStream.hpp" 50 #include "interpreter/interpreter.hpp" 51 #include "jfr/jfrEvents.hpp" 52 #include "logging/log.hpp" 53 #include "logging/logStream.hpp" 54 #include "memory/filemap.hpp" 55 #include "memory/heapShared.hpp" 56 #include "memory/metaspaceClosure.hpp" 57 #include "memory/oopFactory.hpp" 58 #include "memory/resourceArea.hpp" 59 #include "oops/access.inline.hpp" 60 #include "oops/instanceKlass.hpp" 61 #include "oops/instanceRefKlass.hpp" 62 #include "oops/klass.inline.hpp" 63 #include "oops/method.inline.hpp" 64 #include "oops/methodData.hpp" 65 #include "oops/objArrayKlass.hpp" 66 #include "oops/objArrayOop.inline.hpp" 67 #include "oops/oop.inline.hpp" 68 #include "oops/symbol.hpp" 69 #include "oops/typeArrayKlass.hpp" 70 #include "prims/jvmtiExport.hpp" 71 #include "prims/resolvedMethodTable.hpp" 72 #include "prims/methodHandles.hpp" 73 #include "runtime/arguments.hpp" 74 #include "runtime/biasedLocking.hpp" 75 #include "runtime/fieldType.hpp" 76 #include "runtime/handles.inline.hpp" 77 #include "runtime/java.hpp" 78 #include "runtime/javaCalls.hpp" 79 #include "runtime/mutexLocker.hpp" 80 #include "runtime/orderAccess.hpp" 81 #include "runtime/sharedRuntime.hpp" 82 #include "runtime/signature.hpp" 83 #include "services/classLoadingService.hpp" 84 #include "services/diagnosticCommand.hpp" 85 #include "services/threadService.hpp" 86 #include "utilities/macros.hpp" 87 #if INCLUDE_CDS 88 #include "classfile/systemDictionaryShared.hpp" 89 #endif 90 #if INCLUDE_JVMCI 91 #include "jvmci/jvmciRuntime.hpp" 92 #endif 93 #if INCLUDE_JFR 94 #include "jfr/jfr.hpp" 95 #endif 96 97 PlaceholderTable* SystemDictionary::_placeholders = NULL; 98 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 99 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 100 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 101 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; 102 103 int SystemDictionary::_number_of_modifications = 0; 104 oop SystemDictionary::_system_loader_lock_obj = NULL; 105 106 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 107 = { NULL /*, NULL...*/ }; 108 109 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 110 111 oop SystemDictionary::_java_system_loader = NULL; 112 oop SystemDictionary::_java_platform_loader = NULL; 113 114 bool SystemDictionary::_has_checkPackageAccess = false; 115 116 // Default ProtectionDomainCacheSize value 117 118 const int defaultProtectionDomainCacheSize = 1009; 119 120 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL; 121 122 123 // ---------------------------------------------------------------------------- 124 // Java-level SystemLoader and PlatformLoader 125 126 oop SystemDictionary::java_system_loader() { 127 return _java_system_loader; 128 } 129 130 oop SystemDictionary::java_platform_loader() { 131 return _java_platform_loader; 132 } 133 134 void SystemDictionary::compute_java_loaders(TRAPS) { 135 JavaValue result(T_OBJECT); 136 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); 137 JavaCalls::call_static(&result, 138 class_loader_klass, 139 vmSymbols::getSystemClassLoader_name(), 140 vmSymbols::void_classloader_signature(), 141 CHECK); 142 143 _java_system_loader = (oop)result.get_jobject(); 144 145 JavaCalls::call_static(&result, 146 class_loader_klass, 147 vmSymbols::getPlatformClassLoader_name(), 148 vmSymbols::void_classloader_signature(), 149 CHECK); 150 151 _java_platform_loader = (oop)result.get_jobject(); 152 } 153 154 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) { 155 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 156 return ClassLoaderDataGraph::find_or_create(class_loader); 157 } 158 159 // ---------------------------------------------------------------------------- 160 // Parallel class loading check 161 162 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 163 if (class_loader.is_null()) return true; 164 if (AlwaysLockClassLoader) return false; 165 return java_lang_ClassLoader::parallelCapable(class_loader()); 166 } 167 // ---------------------------------------------------------------------------- 168 // ParallelDefineClass flag does not apply to bootclass loader 169 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 170 if (class_loader.is_null()) return false; 171 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 172 return true; 173 } 174 return false; 175 } 176 177 // Returns true if the passed class loader is the builtin application class loader 178 // or a custom system class loader. A customer system class loader can be 179 // specified via -Djava.system.class.loader. 180 bool SystemDictionary::is_system_class_loader(oop class_loader) { 181 if (class_loader == NULL) { 182 return false; 183 } 184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 185 oopDesc::equals(class_loader, _java_system_loader)); 186 } 187 188 // Returns true if the passed class loader is the platform class loader. 189 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 190 if (class_loader == NULL) { 191 return false; 192 } 193 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 194 } 195 196 // ---------------------------------------------------------------------------- 197 // Resolving of classes 198 199 // Forwards to resolve_or_null 200 201 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 202 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 203 if (HAS_PENDING_EXCEPTION || klass == NULL) { 204 // can return a null klass 205 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 206 } 207 return klass; 208 } 209 210 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 211 bool throw_error, 212 Klass* klass, TRAPS) { 213 if (HAS_PENDING_EXCEPTION) { 214 // If we have a pending exception we forward it to the caller, unless throw_error is true, 215 // in which case we have to check whether the pending exception is a ClassNotFoundException, 216 // and if so convert it to a NoClassDefFoundError 217 // And chain the original ClassNotFoundException 218 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 219 ResourceMark rm(THREAD); 220 assert(klass == NULL, "Should not have result with exception pending"); 221 Handle e(THREAD, PENDING_EXCEPTION); 222 CLEAR_PENDING_EXCEPTION; 223 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 224 } else { 225 return NULL; 226 } 227 } 228 // Class not found, throw appropriate error or exception depending on value of throw_error 229 if (klass == NULL) { 230 ResourceMark rm(THREAD); 231 if (throw_error) { 232 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 233 } else { 234 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 235 } 236 } 237 return klass; 238 } 239 240 241 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 242 bool throw_error, TRAPS) 243 { 244 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 245 } 246 247 248 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null 249 250 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 251 if (FieldType::is_array(class_name)) { 252 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 253 } else { 254 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD); 255 } 256 } 257 258 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;" 259 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name, 260 Handle class_loader, 261 Handle protection_domain, 262 TRAPS) { 263 assert(class_name != NULL && !FieldType::is_array(class_name), "must be"); 264 if (FieldType::is_obj(class_name)) { 265 ResourceMark rm(THREAD); 266 // Ignore wrapping L and ;. 267 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 268 class_name->utf8_length() - 2, CHECK_NULL); 269 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 270 } else { 271 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 272 } 273 } 274 275 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 276 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 277 } 278 279 // Forwards to resolve_instance_class_or_null 280 281 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 282 Handle class_loader, 283 Handle protection_domain, 284 TRAPS) { 285 assert(FieldType::is_array(class_name), "must be array"); 286 Klass* k = NULL; 287 FieldArrayInfo fd; 288 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 289 // of this call 290 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 291 if (t == T_OBJECT) { 292 // naked oop "k" is OK here -- we assign back into it 293 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 294 class_loader, 295 protection_domain, 296 CHECK_NULL); 297 if (k != NULL) { 298 k = k->array_klass(fd.dimension(), CHECK_NULL); 299 } 300 } else { 301 k = Universe::typeArrayKlassObj(t); 302 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 303 } 304 return k; 305 } 306 307 308 // Must be called for any super-class or super-interface resolution 309 // during class definition to allow class circularity checking 310 // super-interface callers: 311 // parse_interfaces - for defineClass & jvmtiRedefineClasses 312 // super-class callers: 313 // ClassFileParser - for defineClass & jvmtiRedefineClasses 314 // load_shared_class - while loading a class from shared archive 315 // resolve_instance_class_or_null: 316 // via: handle_parallel_super_load 317 // when resolving a class that has an existing placeholder with 318 // a saved superclass [i.e. a defineClass is currently in progress] 319 // if another thread is trying to resolve the class, it must do 320 // super-class checks on its own thread to catch class circularity 321 // This last call is critical in class circularity checking for cases 322 // where classloading is delegated to different threads and the 323 // classloader lock is released. 324 // Take the case: Base->Super->Base 325 // 1. If thread T1 tries to do a defineClass of class Base 326 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 327 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 328 // so it tries to load Super 329 // 3. If we load the class internally, or user classloader uses same thread 330 // loadClassFromxxx or defineClass via parseClassFile Super ... 331 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 332 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 333 // 3.4 calls resolve_super_or_fail Base 334 // 3.5 finds T1,Base -> throws class circularity 335 //OR 4. If T2 tries to resolve Super via defineClass Super ... 336 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 337 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 338 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 339 // 4.4 finds T2, Super -> throws class circularity 340 // Must be called, even if superclass is null, since this is 341 // where the placeholder entry is created which claims this 342 // thread is loading this class/classloader. 343 // Be careful when modifying this code: once you have run 344 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 345 // you need to find_and_remove it before returning. 346 // So be careful to not exit with a CHECK_ macro betweeen these calls. 347 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 348 Symbol* super_name, 349 Handle class_loader, 350 Handle protection_domain, 351 bool is_superclass, 352 TRAPS) { 353 assert(!FieldType::is_array(super_name), "invalid super class name"); 354 #if INCLUDE_CDS 355 if (DumpSharedSpaces) { 356 // Special processing for handling UNREGISTERED shared classes. 357 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 358 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 359 if (k) { 360 return k; 361 } 362 } 363 #endif // INCLUDE_CDS 364 365 // Double-check, if child class is already loaded, just return super-class,interface 366 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 367 // dictionary. 368 // Make sure there's a placeholder for the *child* before resolving. 369 // Used as a claim that this thread is currently loading superclass/classloader 370 // Used here for ClassCircularity checks and also for heap verification 371 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 372 // Must check ClassCircularity before checking if super class is already loaded. 373 // 374 // We might not already have a placeholder if this child_name was 375 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 376 // the name of the class might not be known until the stream is actually 377 // parsed. 378 // Bugs 4643874, 4715493 379 380 ClassLoaderData* loader_data = class_loader_data(class_loader); 381 Dictionary* dictionary = loader_data->dictionary(); 382 unsigned int d_hash = dictionary->compute_hash(child_name); 383 unsigned int p_hash = placeholders()->compute_hash(child_name); 384 int p_index = placeholders()->hash_to_index(p_hash); 385 // can't throw error holding a lock 386 bool child_already_loaded = false; 387 bool throw_circularity_error = false; 388 { 389 MutexLocker mu(SystemDictionary_lock, THREAD); 390 InstanceKlass* childk = find_class(d_hash, child_name, dictionary); 391 InstanceKlass* quicksuperk; 392 // to support // loading: if child done loading, just return superclass 393 // if super_name, & class_loader don't match: 394 // if initial define, SD update will give LinkageError 395 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 396 // so we don't throw an exception here. 397 // see: nsk redefclass014 & java.lang.instrument Instrument032 398 if ((childk != NULL ) && (is_superclass) && 399 ((quicksuperk = childk->java_super()) != NULL) && 400 ((quicksuperk->name() == super_name) && 401 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) { 402 return quicksuperk; 403 } else { 404 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 405 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 406 throw_circularity_error = true; 407 } 408 } 409 if (!throw_circularity_error) { 410 // Be careful not to exit resolve_super 411 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD); 412 } 413 } 414 if (throw_circularity_error) { 415 ResourceMark rm(THREAD); 416 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 417 } 418 419 // java.lang.Object should have been found above 420 assert(super_name != NULL, "null super class for resolving"); 421 // Resolve the super class or interface, check results on return 422 InstanceKlass* superk = 423 SystemDictionary::resolve_instance_class_or_null_helper(super_name, 424 class_loader, 425 protection_domain, 426 THREAD); 427 428 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 429 // It is no longer necessary to keep the placeholder table alive until update_dictionary 430 // or error. GC used to walk the placeholder table as strong roots. 431 // The instanceKlass is kept alive because the class loader is on the stack, 432 // which keeps the loader_data alive, as well as all instanceKlasses in 433 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 434 { 435 MutexLocker mu(SystemDictionary_lock, THREAD); 436 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 437 SystemDictionary_lock->notify_all(); 438 } 439 if (HAS_PENDING_EXCEPTION || superk == NULL) { 440 // can null superk 441 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD); 442 assert(k == NULL || k == superk, "must be"); 443 if (k == NULL) { 444 superk = NULL; 445 } 446 } 447 448 return superk; 449 } 450 451 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 452 Handle class_loader, 453 Handle protection_domain, 454 TRAPS) { 455 if(!has_checkPackageAccess()) return; 456 457 // Now we have to call back to java to check if the initating class has access 458 JavaValue result(T_VOID); 459 LogTarget(Debug, protectiondomain) lt; 460 if (lt.is_enabled()) { 461 ResourceMark rm; 462 // Print out trace information 463 LogStream ls(lt); 464 ls.print_cr("Checking package access"); 465 if (class_loader() != NULL) { 466 ls.print("class loader: "); 467 class_loader()->print_value_on(&ls); 468 } else { 469 ls.print_cr("class loader: NULL"); 470 } 471 if (protection_domain() != NULL) { 472 ls.print(" protection domain: "); 473 protection_domain()->print_value_on(&ls); 474 } else { 475 ls.print_cr(" protection domain: NULL"); 476 } 477 ls.print(" loading: "); klass->print_value_on(&ls); 478 ls.cr(); 479 } 480 481 // This handle and the class_loader handle passed in keeps this class from 482 // being unloaded through several GC points. 483 // The class_loader handle passed in is the initiating loader. 484 Handle mirror(THREAD, klass->java_mirror()); 485 486 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 487 JavaCalls::call_special(&result, 488 class_loader, 489 system_loader, 490 vmSymbols::checkPackageAccess_name(), 491 vmSymbols::class_protectiondomain_signature(), 492 mirror, 493 protection_domain, 494 THREAD); 495 496 if (HAS_PENDING_EXCEPTION) { 497 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 498 } else { 499 log_debug(protectiondomain)("granted"); 500 } 501 502 if (HAS_PENDING_EXCEPTION) return; 503 504 // If no exception has been thrown, we have validated the protection domain 505 // Insert the protection domain of the initiating class into the set. 506 { 507 ClassLoaderData* loader_data = class_loader_data(class_loader); 508 Dictionary* dictionary = loader_data->dictionary(); 509 510 Symbol* kn = klass->name(); 511 unsigned int d_hash = dictionary->compute_hash(kn); 512 513 MutexLocker mu(SystemDictionary_lock, THREAD); 514 int d_index = dictionary->hash_to_index(d_hash); 515 dictionary->add_protection_domain(d_index, d_hash, klass, 516 protection_domain, THREAD); 517 } 518 } 519 520 // We only get here if this thread finds that another thread 521 // has already claimed the placeholder token for the current operation, 522 // but that other thread either never owned or gave up the 523 // object lock 524 // Waits on SystemDictionary_lock to indicate placeholder table updated 525 // On return, caller must recheck placeholder table state 526 // 527 // We only get here if 528 // 1) custom classLoader, i.e. not bootstrap classloader 529 // 2) custom classLoader has broken the class loader objectLock 530 // so another thread got here in parallel 531 // 532 // lockObject must be held. 533 // Complicated dance due to lock ordering: 534 // Must first release the classloader object lock to 535 // allow initial definer to complete the class definition 536 // and to avoid deadlock 537 // Reclaim classloader lock object with same original recursion count 538 // Must release SystemDictionary_lock after notify, since 539 // class loader lock must be claimed before SystemDictionary_lock 540 // to prevent deadlocks 541 // 542 // The notify allows applications that did an untimed wait() on 543 // the classloader object lock to not hang. 544 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 545 assert_lock_strong(SystemDictionary_lock); 546 547 bool calledholdinglock 548 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 549 assert(calledholdinglock,"must hold lock for notify"); 550 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 551 ObjectSynchronizer::notifyall(lockObject, THREAD); 552 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 553 SystemDictionary_lock->wait(); 554 SystemDictionary_lock->unlock(); 555 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 556 SystemDictionary_lock->lock(); 557 } 558 559 // If the class in is in the placeholder table, class loading is in progress 560 // For cases where the application changes threads to load classes, it 561 // is critical to ClassCircularity detection that we try loading 562 // the superclass on the same thread internally, so we do parallel 563 // super class loading here. 564 // This also is critical in cases where the original thread gets stalled 565 // even in non-circularity situations. 566 // Note: must call resolve_super_or_fail even if null super - 567 // to force placeholder entry creation for this class for circularity detection 568 // Caller must check for pending exception 569 // Returns non-null Klass* if other thread has completed load 570 // and we are done, 571 // If return null Klass* and no pending exception, the caller must load the class 572 InstanceKlass* SystemDictionary::handle_parallel_super_load( 573 Symbol* name, Symbol* superclassname, Handle class_loader, 574 Handle protection_domain, Handle lockObject, TRAPS) { 575 576 ClassLoaderData* loader_data = class_loader_data(class_loader); 577 Dictionary* dictionary = loader_data->dictionary(); 578 unsigned int d_hash = dictionary->compute_hash(name); 579 unsigned int p_hash = placeholders()->compute_hash(name); 580 int p_index = placeholders()->hash_to_index(p_hash); 581 582 // superk is not used, resolve_super called for circularity check only 583 // This code is reached in two situations. One if this thread 584 // is loading the same class twice (e.g. ClassCircularity, or 585 // java.lang.instrument). 586 // The second is if another thread started the resolve_super first 587 // and has not yet finished. 588 // In both cases the original caller will clean up the placeholder 589 // entry on error. 590 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 591 superclassname, 592 class_loader, 593 protection_domain, 594 true, 595 CHECK_NULL); 596 597 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 598 // Serial class loaders and bootstrap classloader do wait for superclass loads 599 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 600 MutexLocker mu(SystemDictionary_lock, THREAD); 601 // Check if classloading completed while we were loading superclass or waiting 602 return find_class(d_hash, name, dictionary); 603 } 604 605 // must loop to both handle other placeholder updates 606 // and spurious notifications 607 bool super_load_in_progress = true; 608 PlaceholderEntry* placeholder; 609 while (super_load_in_progress) { 610 MutexLocker mu(SystemDictionary_lock, THREAD); 611 // Check if classloading completed while we were loading superclass or waiting 612 InstanceKlass* check = find_class(d_hash, name, dictionary); 613 if (check != NULL) { 614 // Klass is already loaded, so just return it 615 return check; 616 } else { 617 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 618 if (placeholder && placeholder->super_load_in_progress() ){ 619 // We only get here if the application has released the 620 // classloader lock when another thread was in the middle of loading a 621 // superclass/superinterface for this class, and now 622 // this thread is also trying to load this class. 623 // To minimize surprises, the first thread that started to 624 // load a class should be the one to complete the loading 625 // with the classfile it initially expected. 626 // This logic has the current thread wait once it has done 627 // all the superclass/superinterface loading it can, until 628 // the original thread completes the class loading or fails 629 // If it completes we will use the resulting InstanceKlass 630 // which we will find below in the systemDictionary. 631 // We also get here for parallel bootstrap classloader 632 if (class_loader.is_null()) { 633 SystemDictionary_lock->wait(); 634 } else { 635 double_lock_wait(lockObject, THREAD); 636 } 637 } else { 638 // If not in SD and not in PH, other thread's load must have failed 639 super_load_in_progress = false; 640 } 641 } 642 } 643 return NULL; 644 } 645 646 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) { 647 assert(event != NULL, "invariant"); 648 assert(k != NULL, "invariant"); 649 assert(event->should_commit(), "invariant"); 650 event->set_loadedClass(k); 651 event->set_definingClassLoader(k->class_loader_data()); 652 event->set_initiatingClassLoader(init_cld); 653 event->commit(); 654 } 655 656 657 // Be careful when modifying this code: once you have run 658 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 659 // you need to find_and_remove it before returning. 660 // So be careful to not exit with a CHECK_ macro betweeen these calls. 661 // 662 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;" 663 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 664 Handle class_loader, 665 Handle protection_domain, 666 TRAPS) { 667 assert(name != NULL && !FieldType::is_array(name) && 668 !FieldType::is_obj(name), "invalid class name"); 669 670 EventClassLoad class_load_start_event; 671 672 HandleMark hm(THREAD); 673 674 // Fix for 4474172; see evaluation for more details 675 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 676 ClassLoaderData* loader_data = register_loader(class_loader); 677 Dictionary* dictionary = loader_data->dictionary(); 678 unsigned int d_hash = dictionary->compute_hash(name); 679 680 // Do lookup to see if class already exist and the protection domain 681 // has the right access 682 // This call uses find which checks protection domain already matches 683 // All subsequent calls use find_class, and set has_loaded_class so that 684 // before we return a result we call out to java to check for valid protection domain 685 // to allow returning the Klass* and add it to the pd_set if it is valid 686 { 687 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain); 688 if (probe != NULL) return probe; 689 } 690 691 // Non-bootstrap class loaders will call out to class loader and 692 // define via jvm/jni_DefineClass which will acquire the 693 // class loader object lock to protect against multiple threads 694 // defining the class in parallel by accident. 695 // This lock must be acquired here so the waiter will find 696 // any successful result in the SystemDictionary and not attempt 697 // the define. 698 // ParallelCapable Classloaders and the bootstrap classloader 699 // do not acquire lock here. 700 bool DoObjectLock = true; 701 if (is_parallelCapable(class_loader)) { 702 DoObjectLock = false; 703 } 704 705 unsigned int p_hash = placeholders()->compute_hash(name); 706 int p_index = placeholders()->hash_to_index(p_hash); 707 708 // Class is not in SystemDictionary so we have to do loading. 709 // Make sure we are synchronized on the class loader before we proceed 710 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 711 check_loader_lock_contention(lockObject, THREAD); 712 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 713 714 // Check again (after locking) if class already exist in SystemDictionary 715 bool class_has_been_loaded = false; 716 bool super_load_in_progress = false; 717 bool havesupername = false; 718 InstanceKlass* k = NULL; 719 PlaceholderEntry* placeholder; 720 Symbol* superclassname = NULL; 721 722 assert(THREAD->can_call_java(), 723 "can not load classes with compiler thread: class=%s, classloader=%s", 724 name->as_C_string(), 725 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 726 { 727 MutexLocker mu(SystemDictionary_lock, THREAD); 728 InstanceKlass* check = find_class(d_hash, name, dictionary); 729 if (check != NULL) { 730 // InstanceKlass is already loaded, so just return it 731 class_has_been_loaded = true; 732 k = check; 733 } else { 734 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 735 if (placeholder && placeholder->super_load_in_progress()) { 736 super_load_in_progress = true; 737 if (placeholder->havesupername() == true) { 738 superclassname = placeholder->supername(); 739 havesupername = true; 740 } 741 } 742 } 743 } 744 745 // If the class is in the placeholder table, class loading is in progress 746 if (super_load_in_progress && havesupername==true) { 747 k = handle_parallel_super_load(name, 748 superclassname, 749 class_loader, 750 protection_domain, 751 lockObject, THREAD); 752 if (HAS_PENDING_EXCEPTION) { 753 return NULL; 754 } 755 if (k != NULL) { 756 class_has_been_loaded = true; 757 } 758 } 759 760 bool throw_circularity_error = false; 761 if (!class_has_been_loaded) { 762 bool load_instance_added = false; 763 764 // add placeholder entry to record loading instance class 765 // Five cases: 766 // All cases need to prevent modifying bootclasssearchpath 767 // in parallel with a classload of same classname 768 // Redefineclasses uses existence of the placeholder for the duration 769 // of the class load to prevent concurrent redefinition of not completely 770 // defined classes. 771 // case 1. traditional classloaders that rely on the classloader object lock 772 // - no other need for LOAD_INSTANCE 773 // case 2. traditional classloaders that break the classloader object lock 774 // as a deadlock workaround. Detection of this case requires that 775 // this check is done while holding the classloader object lock, 776 // and that lock is still held when calling classloader's loadClass. 777 // For these classloaders, we ensure that the first requestor 778 // completes the load and other requestors wait for completion. 779 // case 3. Bootstrap classloader - don't own objectLocker 780 // This classloader supports parallelism at the classloader level, 781 // but only allows a single load of a class/classloader pair. 782 // No performance benefit and no deadlock issues. 783 // case 4. parallelCapable user level classloaders - without objectLocker 784 // Allow parallel classloading of a class/classloader pair 785 786 { 787 MutexLocker mu(SystemDictionary_lock, THREAD); 788 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 789 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 790 if (oldprobe) { 791 // only need check_seen_thread once, not on each loop 792 // 6341374 java/lang/Instrument with -Xcomp 793 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 794 throw_circularity_error = true; 795 } else { 796 // case 1: traditional: should never see load_in_progress. 797 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 798 799 // case 3: bootstrap classloader: prevent futile classloading, 800 // wait on first requestor 801 if (class_loader.is_null()) { 802 SystemDictionary_lock->wait(); 803 } else { 804 // case 2: traditional with broken classloader lock. wait on first 805 // requestor. 806 double_lock_wait(lockObject, THREAD); 807 } 808 // Check if classloading completed while we were waiting 809 InstanceKlass* check = find_class(d_hash, name, dictionary); 810 if (check != NULL) { 811 // Klass is already loaded, so just return it 812 k = check; 813 class_has_been_loaded = true; 814 } 815 // check if other thread failed to load and cleaned up 816 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 817 } 818 } 819 } 820 } 821 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 822 // case 4: parallelCapable: allow competing threads to try 823 // LOAD_INSTANCE in parallel 824 825 if (!throw_circularity_error && !class_has_been_loaded) { 826 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 827 load_instance_added = true; 828 // For class loaders that do not acquire the classloader object lock, 829 // if they did not catch another thread holding LOAD_INSTANCE, 830 // need a check analogous to the acquire ObjectLocker/find_class 831 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 832 // one final check if the load has already completed 833 // class loaders holding the ObjectLock shouldn't find the class here 834 InstanceKlass* check = find_class(d_hash, name, dictionary); 835 if (check != NULL) { 836 // Klass is already loaded, so return it after checking/adding protection domain 837 k = check; 838 class_has_been_loaded = true; 839 } 840 } 841 } 842 843 // must throw error outside of owning lock 844 if (throw_circularity_error) { 845 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 846 ResourceMark rm(THREAD); 847 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 848 } 849 850 if (!class_has_been_loaded) { 851 852 // Do actual loading 853 k = load_instance_class(name, class_loader, THREAD); 854 855 // If everything was OK (no exceptions, no null return value), and 856 // class_loader is NOT the defining loader, do a little more bookkeeping. 857 if (!HAS_PENDING_EXCEPTION && k != NULL && 858 !oopDesc::equals(k->class_loader(), class_loader())) { 859 860 check_constraints(d_hash, k, class_loader, false, THREAD); 861 862 // Need to check for a PENDING_EXCEPTION again; check_constraints 863 // can throw but we may have to remove entry from the placeholder table below. 864 if (!HAS_PENDING_EXCEPTION) { 865 // Record dependency for non-parent delegation. 866 // This recording keeps the defining class loader of the klass (k) found 867 // from being unloaded while the initiating class loader is loaded 868 // even if the reference to the defining class loader is dropped 869 // before references to the initiating class loader. 870 loader_data->record_dependency(k); 871 872 { // Grabbing the Compile_lock prevents systemDictionary updates 873 // during compilations. 874 MutexLocker mu(Compile_lock, THREAD); 875 update_dictionary(d_hash, p_index, p_hash, 876 k, class_loader, THREAD); 877 } 878 879 if (JvmtiExport::should_post_class_load()) { 880 Thread *thread = THREAD; 881 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 882 JvmtiExport::post_class_load((JavaThread *) thread, k); 883 } 884 } 885 } 886 } // load_instance_class 887 888 if (load_instance_added == true) { 889 // clean up placeholder entries for LOAD_INSTANCE success or error 890 // This brackets the SystemDictionary updates for both defining 891 // and initiating loaders 892 MutexLocker mu(SystemDictionary_lock, THREAD); 893 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 894 SystemDictionary_lock->notify_all(); 895 } 896 } 897 898 if (HAS_PENDING_EXCEPTION || k == NULL) { 899 return NULL; 900 } 901 if (class_load_start_event.should_commit()) { 902 post_class_load_event(&class_load_start_event, k, loader_data); 903 } 904 #ifdef ASSERT 905 { 906 ClassLoaderData* loader_data = k->class_loader_data(); 907 MutexLocker mu(SystemDictionary_lock, THREAD); 908 InstanceKlass* kk = find_class(name, loader_data); 909 assert(kk == k, "should be present in dictionary"); 910 } 911 #endif 912 913 // return if the protection domain in NULL 914 if (protection_domain() == NULL) return k; 915 916 // Check the protection domain has the right access 917 if (dictionary->is_valid_protection_domain(d_hash, name, 918 protection_domain)) { 919 return k; 920 } 921 922 // Verify protection domain. If it fails an exception is thrown 923 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 924 925 return k; 926 } 927 928 929 // This routine does not lock the system dictionary. 930 // 931 // Since readers don't hold a lock, we must make sure that system 932 // dictionary entries are only removed at a safepoint (when only one 933 // thread is running), and are added to in a safe way (all links must 934 // be updated in an MT-safe manner). 935 // 936 // Callers should be aware that an entry could be added just after 937 // _dictionary->bucket(index) is read here, so the caller will not see 938 // the new entry. 939 940 Klass* SystemDictionary::find(Symbol* class_name, 941 Handle class_loader, 942 Handle protection_domain, 943 TRAPS) { 944 945 // The result of this call should be consistent with the result 946 // of the call to resolve_instance_class_or_null(). 947 // See evaluation 6790209 and 4474172 for more details. 948 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 949 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 950 951 if (loader_data == NULL) { 952 // If the ClassLoaderData has not been setup, 953 // then the class loader has no entries in the dictionary. 954 return NULL; 955 } 956 957 Dictionary* dictionary = loader_data->dictionary(); 958 unsigned int d_hash = dictionary->compute_hash(class_name); 959 return dictionary->find(d_hash, class_name, 960 protection_domain); 961 } 962 963 964 // Look for a loaded instance or array klass by name. Do not do any loading. 965 // return NULL in case of error. 966 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 967 Handle class_loader, 968 Handle protection_domain, 969 TRAPS) { 970 Klass* k = NULL; 971 assert(class_name != NULL, "class name must be non NULL"); 972 973 if (FieldType::is_array(class_name)) { 974 // The name refers to an array. Parse the name. 975 // dimension and object_key in FieldArrayInfo are assigned as a 976 // side-effect of this call 977 FieldArrayInfo fd; 978 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 979 if (t != T_OBJECT) { 980 k = Universe::typeArrayKlassObj(t); 981 } else { 982 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 983 } 984 if (k != NULL) { 985 k = k->array_klass_or_null(fd.dimension()); 986 } 987 } else { 988 k = find(class_name, class_loader, protection_domain, THREAD); 989 } 990 return k; 991 } 992 993 // Note: this method is much like resolve_from_stream, but 994 // does not publish the classes via the SystemDictionary. 995 // Handles unsafe_DefineAnonymousClass and redefineclasses 996 // RedefinedClasses do not add to the class hierarchy 997 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 998 Handle class_loader, 999 Handle protection_domain, 1000 ClassFileStream* st, 1001 const InstanceKlass* unsafe_anonymous_host, 1002 GrowableArray<Handle>* cp_patches, 1003 TRAPS) { 1004 1005 EventClassLoad class_load_start_event; 1006 1007 ClassLoaderData* loader_data; 1008 if (unsafe_anonymous_host != NULL) { 1009 // Create a new CLD for an unsafe anonymous class, that uses the same class loader 1010 // as the unsafe_anonymous_host 1011 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same"); 1012 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader); 1013 } else { 1014 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1015 } 1016 1017 assert(st != NULL, "invariant"); 1018 assert(st->need_verify(), "invariant"); 1019 1020 // Parse stream and create a klass. 1021 // Note that we do this even though this klass might 1022 // already be present in the SystemDictionary, otherwise we would not 1023 // throw potential ClassFormatErrors. 1024 1025 InstanceKlass* k = KlassFactory::create_from_stream(st, 1026 class_name, 1027 loader_data, 1028 protection_domain, 1029 unsafe_anonymous_host, 1030 cp_patches, 1031 CHECK_NULL); 1032 1033 if (unsafe_anonymous_host != NULL && k != NULL) { 1034 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader) 1035 // so that they can be unloaded when the mirror is no longer referenced. 1036 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror())); 1037 1038 { 1039 MutexLocker mu_r(Compile_lock, THREAD); 1040 1041 // Add to class hierarchy, initialize vtables, and do possible 1042 // deoptimizations. 1043 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1044 1045 // But, do not add to dictionary. 1046 1047 // compiled code dependencies need to be validated anyway 1048 notice_modification(); 1049 } 1050 1051 // Rewrite and patch constant pool here. 1052 k->link_class(CHECK_NULL); 1053 if (cp_patches != NULL) { 1054 k->constants()->patch_resolved_references(cp_patches); 1055 } 1056 1057 // If it's anonymous, initialize it now, since nobody else will. 1058 k->eager_initialize(CHECK_NULL); 1059 1060 // notify jvmti 1061 if (JvmtiExport::should_post_class_load()) { 1062 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1063 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1064 } 1065 if (class_load_start_event.should_commit()) { 1066 post_class_load_event(&class_load_start_event, k, loader_data); 1067 } 1068 } 1069 assert(unsafe_anonymous_host != NULL || NULL == cp_patches, 1070 "cp_patches only found with unsafe_anonymous_host"); 1071 1072 return k; 1073 } 1074 1075 // Add a klass to the system from a stream (called by jni_DefineClass and 1076 // JVM_DefineClass). 1077 // Note: class_name can be NULL. In that case we do not know the name of 1078 // the class until we have parsed the stream. 1079 1080 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1081 Handle class_loader, 1082 Handle protection_domain, 1083 ClassFileStream* st, 1084 TRAPS) { 1085 1086 HandleMark hm(THREAD); 1087 1088 // Classloaders that support parallelism, e.g. bootstrap classloader, 1089 // do not acquire lock here 1090 bool DoObjectLock = true; 1091 if (is_parallelCapable(class_loader)) { 1092 DoObjectLock = false; 1093 } 1094 1095 ClassLoaderData* loader_data = register_loader(class_loader); 1096 1097 // Make sure we are synchronized on the class loader before we proceed 1098 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1099 check_loader_lock_contention(lockObject, THREAD); 1100 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1101 1102 assert(st != NULL, "invariant"); 1103 1104 // Parse the stream and create a klass. 1105 // Note that we do this even though this klass might 1106 // already be present in the SystemDictionary, otherwise we would not 1107 // throw potential ClassFormatErrors. 1108 InstanceKlass* k = NULL; 1109 1110 #if INCLUDE_CDS 1111 if (!DumpSharedSpaces) { 1112 k = SystemDictionaryShared::lookup_from_stream(class_name, 1113 class_loader, 1114 protection_domain, 1115 st, 1116 CHECK_NULL); 1117 } 1118 #endif 1119 1120 if (k == NULL) { 1121 if (st->buffer() == NULL) { 1122 return NULL; 1123 } 1124 k = KlassFactory::create_from_stream(st, 1125 class_name, 1126 loader_data, 1127 protection_domain, 1128 NULL, // unsafe_anonymous_host 1129 NULL, // cp_patches 1130 CHECK_NULL); 1131 } 1132 1133 assert(k != NULL, "no klass created"); 1134 Symbol* h_name = k->name(); 1135 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1136 1137 // Add class just loaded 1138 // If a class loader supports parallel classloading handle parallel define requests 1139 // find_or_define_instance_class may return a different InstanceKlass 1140 if (is_parallelCapable(class_loader)) { 1141 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1142 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1143 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1144 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1145 loader_data->add_to_deallocate_list(k); 1146 k = defined_k; 1147 } 1148 } else { 1149 define_instance_class(k, THREAD); 1150 } 1151 1152 // If defining the class throws an exception register 'k' for cleanup. 1153 if (HAS_PENDING_EXCEPTION) { 1154 assert(k != NULL, "Must have an instance klass here!"); 1155 loader_data->add_to_deallocate_list(k); 1156 return NULL; 1157 } 1158 1159 // Make sure we have an entry in the SystemDictionary on success 1160 debug_only( { 1161 MutexLocker mu(SystemDictionary_lock, THREAD); 1162 1163 Klass* check = find_class(h_name, k->class_loader_data()); 1164 assert(check == k, "should be present in the dictionary"); 1165 } ); 1166 1167 return k; 1168 } 1169 1170 #if INCLUDE_CDS 1171 // Load a class for boot loader from the shared spaces. This also 1172 // forces the super class and all interfaces to be loaded. 1173 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name, 1174 TRAPS) { 1175 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name); 1176 if (ik != NULL && ik->is_shared_boot_class()) { 1177 return load_shared_class(ik, Handle(), Handle(), THREAD); 1178 } 1179 return NULL; 1180 } 1181 1182 // Check if a shared class can be loaded by the specific classloader: 1183 // 1184 // NULL classloader: 1185 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1186 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1187 // be defined in an unnamed module. 1188 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1189 InstanceKlass* ik, 1190 Handle class_loader, TRAPS) { 1191 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1192 "Cannot use sharing if java.base is patched"); 1193 ResourceMark rm; 1194 int path_index = ik->shared_classpath_index(); 1195 ClassLoaderData* loader_data = class_loader_data(class_loader); 1196 if (path_index < 0) { 1197 // path_index < 0 indicates that the class is intended for a custom loader 1198 // and should not be loaded by boot/platform/app loaders 1199 if (loader_data->is_builtin_class_loader_data()) { 1200 return false; 1201 } else { 1202 return true; 1203 } 1204 } 1205 SharedClassPathEntry* ent = 1206 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); 1207 if (!Universe::is_module_initialized()) { 1208 assert(ent != NULL && ent->is_modules_image(), 1209 "Loading non-bootstrap classes before the module system is initialized"); 1210 assert(class_loader.is_null(), "sanity"); 1211 return true; 1212 } 1213 // Get the pkg_entry from the classloader 1214 TempNewSymbol pkg_name = NULL; 1215 PackageEntry* pkg_entry = NULL; 1216 ModuleEntry* mod_entry = NULL; 1217 const char* pkg_string = NULL; 1218 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1219 if (pkg_name != NULL) { 1220 pkg_string = pkg_name->as_C_string(); 1221 if (loader_data != NULL) { 1222 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1223 } 1224 if (pkg_entry != NULL) { 1225 mod_entry = pkg_entry->module(); 1226 } 1227 } 1228 1229 // If the archived class is from a module that has been patched at runtime, 1230 // the class cannot be loaded from the archive. 1231 if (mod_entry != NULL && mod_entry->is_patched()) { 1232 return false; 1233 } 1234 1235 if (class_loader.is_null()) { 1236 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1237 // The NULL classloader can load archived class originated from the 1238 // "modules" jimage and the -Xbootclasspath/a. For class from the 1239 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1240 // by the NULL classloader. 1241 if (mod_entry != NULL) { 1242 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1243 // ModuleEntry's location agrees with the archived class' origination. 1244 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1245 return true; // Module class from the "module" jimage 1246 } 1247 } 1248 1249 // If the archived class is not from the "module" jimage, the class can be 1250 // loaded by the NULL classloader if 1251 // 1252 // 1. the class is from the unamed package 1253 // 2. or, the class is not from a module defined in the NULL classloader 1254 // 3. or, the class is from an unamed module 1255 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1256 // the class is from the -Xbootclasspath/a 1257 if (pkg_string == NULL || 1258 pkg_entry == NULL || 1259 pkg_entry->in_unnamed_module()) { 1260 assert(mod_entry == NULL || 1261 mod_entry == loader_data->unnamed_module(), 1262 "the unnamed module is not defined in the classloader"); 1263 return true; 1264 } 1265 } 1266 return false; 1267 } else { 1268 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1269 ik, class_loader, pkg_string, pkg_name, 1270 pkg_entry, mod_entry, CHECK_(false)); 1271 return res; 1272 } 1273 } 1274 1275 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1276 Handle class_loader, 1277 Handle protection_domain, TRAPS) { 1278 1279 if (ik != NULL) { 1280 Symbol* class_name = ik->name(); 1281 1282 bool visible = is_shared_class_visible( 1283 class_name, ik, class_loader, CHECK_NULL); 1284 if (!visible) { 1285 return NULL; 1286 } 1287 1288 // Resolve the superclass and interfaces. They must be the same 1289 // as in dump time, because the layout of <ik> depends on 1290 // the specific layout of ik->super() and ik->local_interfaces(). 1291 // 1292 // If unexpected superclass or interfaces are found, we cannot 1293 // load <ik> from the shared archive. 1294 1295 if (ik->super() != NULL) { 1296 Symbol* cn = ik->super()->name(); 1297 Klass *s = resolve_super_or_fail(class_name, cn, 1298 class_loader, protection_domain, true, CHECK_NULL); 1299 if (s != ik->super()) { 1300 // The dynamically resolved super class is not the same as the one we used during dump time, 1301 // so we cannot use ik. 1302 return NULL; 1303 } else { 1304 assert(s->is_shared(), "must be"); 1305 } 1306 } 1307 1308 Array<InstanceKlass*>* interfaces = ik->local_interfaces(); 1309 int num_interfaces = interfaces->length(); 1310 for (int index = 0; index < num_interfaces; index++) { 1311 InstanceKlass* k = interfaces->at(index); 1312 Symbol* name = k->name(); 1313 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1314 if (k != i) { 1315 // The dynamically resolved interface class is not the same as the one we used during dump time, 1316 // so we cannot use ik. 1317 return NULL; 1318 } else { 1319 assert(i->is_shared(), "must be"); 1320 } 1321 } 1322 1323 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1324 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1325 if (new_ik != NULL) { 1326 // The class is changed by CFLH. Return the new class. The shared class is 1327 // not used. 1328 return new_ik; 1329 } 1330 1331 // Adjust methods to recover missing data. They need addresses for 1332 // interpreter entry points and their default native method address 1333 // must be reset. 1334 1335 // Updating methods must be done under a lock so multiple 1336 // threads don't update these in parallel 1337 // 1338 // Shared classes are all currently loaded by either the bootstrap or 1339 // internal parallel class loaders, so this will never cause a deadlock 1340 // on a custom class loader lock. 1341 1342 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1343 { 1344 HandleMark hm(THREAD); 1345 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1346 check_loader_lock_contention(lockObject, THREAD); 1347 ObjectLocker ol(lockObject, THREAD, true); 1348 // prohibited package check assumes all classes loaded from archive call 1349 // restore_unshareable_info which calls ik->set_package() 1350 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1351 } 1352 1353 ik->print_class_load_logging(loader_data, NULL, NULL); 1354 1355 // For boot loader, ensure that GetSystemPackage knows that a class in this 1356 // package was loaded. 1357 if (class_loader.is_null()) { 1358 int path_index = ik->shared_classpath_index(); 1359 ResourceMark rm; 1360 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1361 } 1362 1363 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1364 // Only dump the classes that can be stored into CDS archive 1365 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1366 ResourceMark rm(THREAD); 1367 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1368 classlist_file->flush(); 1369 } 1370 } 1371 1372 // notify a class loaded from shared object 1373 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1374 1375 ik->set_has_passed_fingerprint_check(false); 1376 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1377 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1378 uint64_t cds_fp = ik->get_stored_fingerprint(); 1379 if (aot_fp != 0 && aot_fp == cds_fp) { 1380 // This class matches with a class saved in an AOT library 1381 ik->set_has_passed_fingerprint_check(true); 1382 } else { 1383 ResourceMark rm; 1384 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1385 } 1386 } 1387 } 1388 return ik; 1389 } 1390 #endif // INCLUDE_CDS 1391 1392 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1393 1394 if (class_loader.is_null()) { 1395 ResourceMark rm; 1396 PackageEntry* pkg_entry = NULL; 1397 bool search_only_bootloader_append = false; 1398 ClassLoaderData *loader_data = class_loader_data(class_loader); 1399 1400 // Find the package in the boot loader's package entry table. 1401 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1402 if (pkg_name != NULL) { 1403 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1404 } 1405 1406 // Prior to attempting to load the class, enforce the boot loader's 1407 // visibility boundaries. 1408 if (!Universe::is_module_initialized()) { 1409 // During bootstrapping, prior to module initialization, any 1410 // class attempting to be loaded must be checked against the 1411 // java.base packages in the boot loader's PackageEntryTable. 1412 // No class outside of java.base is allowed to be loaded during 1413 // this bootstrapping window. 1414 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1415 // Class is either in the unnamed package or in 1416 // a named package within the unnamed module. Either 1417 // case is outside of java.base, do not attempt to 1418 // load the class post java.base definition. If 1419 // java.base has not been defined, let the class load 1420 // and its package will be checked later by 1421 // ModuleEntryTable::verify_javabase_packages. 1422 if (ModuleEntryTable::javabase_defined()) { 1423 return NULL; 1424 } 1425 } else { 1426 // Check that the class' package is defined within java.base. 1427 ModuleEntry* mod_entry = pkg_entry->module(); 1428 Symbol* mod_entry_name = mod_entry->name(); 1429 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1430 return NULL; 1431 } 1432 } 1433 } else { 1434 // After the module system has been initialized, check if the class' 1435 // package is in a module defined to the boot loader. 1436 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1437 // Class is either in the unnamed package, in a named package 1438 // within a module not defined to the boot loader or in a 1439 // a named package within the unnamed module. In all cases, 1440 // limit visibility to search for the class only in the boot 1441 // loader's append path. 1442 search_only_bootloader_append = true; 1443 } 1444 } 1445 1446 // Prior to bootstrapping's module initialization, never load a class outside 1447 // of the boot loader's module path 1448 assert(Universe::is_module_initialized() || 1449 !search_only_bootloader_append, 1450 "Attempt to load a class outside of boot loader's module path"); 1451 1452 // Search for classes in the CDS archive. 1453 InstanceKlass* k = NULL; 1454 { 1455 #if INCLUDE_CDS 1456 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1457 k = load_shared_boot_class(class_name, THREAD); 1458 #endif 1459 } 1460 1461 if (k == NULL) { 1462 // Use VM class loader 1463 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1464 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1465 } 1466 1467 // find_or_define_instance_class may return a different InstanceKlass 1468 if (k != NULL) { 1469 InstanceKlass* defined_k = 1470 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1471 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1472 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1473 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1474 loader_data->add_to_deallocate_list(k); 1475 k = defined_k; 1476 } else if (HAS_PENDING_EXCEPTION) { 1477 loader_data->add_to_deallocate_list(k); 1478 return NULL; 1479 } 1480 } 1481 return k; 1482 } else { 1483 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1484 ResourceMark rm(THREAD); 1485 1486 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1487 JavaThread* jt = (JavaThread*) THREAD; 1488 1489 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1490 ClassLoader::perf_app_classload_selftime(), 1491 ClassLoader::perf_app_classload_count(), 1492 jt->get_thread_stat()->perf_recursion_counts_addr(), 1493 jt->get_thread_stat()->perf_timers_addr(), 1494 PerfClassTraceTime::CLASS_LOAD); 1495 1496 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1497 // Translate to external class name format, i.e., convert '/' chars to '.' 1498 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1499 1500 JavaValue result(T_OBJECT); 1501 1502 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1503 1504 // Call public unsynchronized loadClass(String) directly for all class loaders. 1505 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1506 // acquire a class-name based lock rather than the class loader object lock. 1507 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1508 JavaCalls::call_virtual(&result, 1509 class_loader, 1510 spec_klass, 1511 vmSymbols::loadClass_name(), 1512 vmSymbols::string_class_signature(), 1513 string, 1514 CHECK_NULL); 1515 1516 assert(result.get_type() == T_OBJECT, "just checking"); 1517 oop obj = (oop) result.get_jobject(); 1518 1519 // Primitive classes return null since forName() can not be 1520 // used to obtain any of the Class objects representing primitives or void 1521 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1522 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1523 // For user defined Java class loaders, check that the name returned is 1524 // the same as that requested. This check is done for the bootstrap 1525 // loader when parsing the class file. 1526 if (class_name == k->name()) { 1527 return k; 1528 } 1529 } 1530 // Class is not found or has the wrong name, return NULL 1531 return NULL; 1532 } 1533 } 1534 1535 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) { 1536 EventClassDefine event; 1537 if (event.should_commit()) { 1538 event.set_definedClass(k); 1539 event.set_definingClassLoader(def_cld); 1540 event.commit(); 1541 } 1542 } 1543 1544 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1545 1546 HandleMark hm(THREAD); 1547 ClassLoaderData* loader_data = k->class_loader_data(); 1548 Handle class_loader_h(THREAD, loader_data->class_loader()); 1549 1550 // for bootstrap and other parallel classloaders don't acquire lock, 1551 // use placeholder token 1552 // If a parallelCapable class loader calls define_instance_class instead of 1553 // find_or_define_instance_class to get here, we have a timing 1554 // hole with systemDictionary updates and check_constraints 1555 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1556 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1557 compute_loader_lock_object(class_loader_h, THREAD)), 1558 "define called without lock"); 1559 } 1560 1561 // Check class-loading constraints. Throw exception if violation is detected. 1562 // Grabs and releases SystemDictionary_lock 1563 // The check_constraints/find_class call and update_dictionary sequence 1564 // must be "atomic" for a specific class/classloader pair so we never 1565 // define two different instanceKlasses for that class/classloader pair. 1566 // Existing classloaders will call define_instance_class with the 1567 // classloader lock held 1568 // Parallel classloaders will call find_or_define_instance_class 1569 // which will require a token to perform the define class 1570 Symbol* name_h = k->name(); 1571 Dictionary* dictionary = loader_data->dictionary(); 1572 unsigned int d_hash = dictionary->compute_hash(name_h); 1573 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1574 1575 // Register class just loaded with class loader (placed in Vector) 1576 // Note we do this before updating the dictionary, as this can 1577 // fail with an OutOfMemoryError (if it does, we will *not* put this 1578 // class in the dictionary and will not update the class hierarchy). 1579 // JVMTI FollowReferences needs to find the classes this way. 1580 if (k->class_loader() != NULL) { 1581 methodHandle m(THREAD, Universe::loader_addClass_method()); 1582 JavaValue result(T_VOID); 1583 JavaCallArguments args(class_loader_h); 1584 args.push_oop(Handle(THREAD, k->java_mirror())); 1585 JavaCalls::call(&result, m, &args, CHECK); 1586 } 1587 1588 // Add the new class. We need recompile lock during update of CHA. 1589 { 1590 unsigned int p_hash = placeholders()->compute_hash(name_h); 1591 int p_index = placeholders()->hash_to_index(p_hash); 1592 1593 MutexLocker mu_r(Compile_lock, THREAD); 1594 1595 // Add to class hierarchy, initialize vtables, and do possible 1596 // deoptimizations. 1597 add_to_hierarchy(k, CHECK); // No exception, but can block 1598 1599 // Add to systemDictionary - so other classes can see it. 1600 // Grabs and releases SystemDictionary_lock 1601 update_dictionary(d_hash, p_index, p_hash, 1602 k, class_loader_h, THREAD); 1603 } 1604 k->eager_initialize(THREAD); 1605 1606 // notify jvmti 1607 if (JvmtiExport::should_post_class_load()) { 1608 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1609 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1610 1611 } 1612 post_class_define_event(k, loader_data); 1613 } 1614 1615 // Support parallel classloading 1616 // All parallel class loaders, including bootstrap classloader 1617 // lock a placeholder entry for this class/class_loader pair 1618 // to allow parallel defines of different classes for this class loader 1619 // With AllowParallelDefine flag==true, in case they do not synchronize around 1620 // FindLoadedClass/DefineClass, calls, we check for parallel 1621 // loading for them, wait if a defineClass is in progress 1622 // and return the initial requestor's results 1623 // This flag does not apply to the bootstrap classloader. 1624 // With AllowParallelDefine flag==false, call through to define_instance_class 1625 // which will throw LinkageError: duplicate class definition. 1626 // False is the requested default. 1627 // For better performance, the class loaders should synchronize 1628 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1629 // potentially waste time reading and parsing the bytestream. 1630 // Note: VM callers should ensure consistency of k/class_name,class_loader 1631 // Be careful when modifying this code: once you have run 1632 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1633 // you need to find_and_remove it before returning. 1634 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1635 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1636 InstanceKlass* k, TRAPS) { 1637 1638 Symbol* name_h = k->name(); // passed in class_name may be null 1639 ClassLoaderData* loader_data = class_loader_data(class_loader); 1640 Dictionary* dictionary = loader_data->dictionary(); 1641 1642 unsigned int d_hash = dictionary->compute_hash(name_h); 1643 1644 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1645 unsigned int p_hash = placeholders()->compute_hash(name_h); 1646 int p_index = placeholders()->hash_to_index(p_hash); 1647 PlaceholderEntry* probe; 1648 1649 { 1650 MutexLocker mu(SystemDictionary_lock, THREAD); 1651 // First check if class already defined 1652 if (is_parallelDefine(class_loader)) { 1653 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1654 if (check != NULL) { 1655 return check; 1656 } 1657 } 1658 1659 // Acquire define token for this class/classloader 1660 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1661 // Wait if another thread defining in parallel 1662 // All threads wait - even those that will throw duplicate class: otherwise 1663 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1664 // if other thread has not finished updating dictionary 1665 while (probe->definer() != NULL) { 1666 SystemDictionary_lock->wait(); 1667 } 1668 // Only special cases allow parallel defines and can use other thread's results 1669 // Other cases fall through, and may run into duplicate defines 1670 // caught by finding an entry in the SystemDictionary 1671 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1672 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1673 SystemDictionary_lock->notify_all(); 1674 #ifdef ASSERT 1675 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1676 assert(check != NULL, "definer missed recording success"); 1677 #endif 1678 return probe->instance_klass(); 1679 } else { 1680 // This thread will define the class (even if earlier thread tried and had an error) 1681 probe->set_definer(THREAD); 1682 } 1683 } 1684 1685 define_instance_class(k, THREAD); 1686 1687 Handle linkage_exception = Handle(); // null handle 1688 1689 // definer must notify any waiting threads 1690 { 1691 MutexLocker mu(SystemDictionary_lock, THREAD); 1692 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1693 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1694 if (probe != NULL) { 1695 if (HAS_PENDING_EXCEPTION) { 1696 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1697 CLEAR_PENDING_EXCEPTION; 1698 } else { 1699 probe->set_instance_klass(k); 1700 } 1701 probe->set_definer(NULL); 1702 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1703 SystemDictionary_lock->notify_all(); 1704 } 1705 } 1706 1707 // Can't throw exception while holding lock due to rank ordering 1708 if (linkage_exception() != NULL) { 1709 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1710 } 1711 1712 return k; 1713 } 1714 1715 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1716 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1717 if (class_loader.is_null()) { 1718 return Handle(THREAD, _system_loader_lock_obj); 1719 } else { 1720 return class_loader; 1721 } 1722 } 1723 1724 // This method is added to check how often we have to wait to grab loader 1725 // lock. The results are being recorded in the performance counters defined in 1726 // ClassLoader::_sync_systemLoaderLockContentionRate and 1727 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1728 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1729 if (!UsePerfData) { 1730 return; 1731 } 1732 1733 assert(!loader_lock.is_null(), "NULL lock object"); 1734 1735 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1736 == ObjectSynchronizer::owner_other) { 1737 // contention will likely happen, so increment the corresponding 1738 // contention counter. 1739 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) { 1740 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1741 } else { 1742 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1743 } 1744 } 1745 } 1746 1747 // ---------------------------------------------------------------------------- 1748 // Lookup 1749 1750 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1751 Symbol* class_name, 1752 Dictionary* dictionary) { 1753 assert_locked_or_safepoint(SystemDictionary_lock); 1754 int index = dictionary->hash_to_index(hash); 1755 return dictionary->find_class(index, hash, class_name); 1756 } 1757 1758 1759 // Basic find on classes in the midst of being loaded 1760 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1761 ClassLoaderData* loader_data) { 1762 assert_locked_or_safepoint(SystemDictionary_lock); 1763 unsigned int p_hash = placeholders()->compute_hash(class_name); 1764 int p_index = placeholders()->hash_to_index(p_hash); 1765 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1766 } 1767 1768 1769 // Used for assertions and verification only 1770 // Precalculating the hash and index is an optimization because there are many lookups 1771 // before adding the class. 1772 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1773 assert_locked_or_safepoint(SystemDictionary_lock); 1774 #ifndef ASSERT 1775 guarantee(VerifyBeforeGC || 1776 VerifyDuringGC || 1777 VerifyBeforeExit || 1778 VerifyDuringStartup || 1779 VerifyAfterGC, "too expensive"); 1780 #endif 1781 1782 Dictionary* dictionary = loader_data->dictionary(); 1783 unsigned int d_hash = dictionary->compute_hash(class_name); 1784 return find_class(d_hash, class_name, dictionary); 1785 } 1786 1787 1788 // ---------------------------------------------------------------------------- 1789 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1790 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1791 // before a new class is used. 1792 1793 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1794 assert(k != NULL, "just checking"); 1795 assert_locked_or_safepoint(Compile_lock); 1796 1797 k->set_init_state(InstanceKlass::loaded); 1798 // make sure init_state store is already done. 1799 // The compiler reads the hierarchy outside of the Compile_lock. 1800 // Access ordering is used to add to hierarchy. 1801 1802 // Link into hierachy. 1803 k->append_to_sibling_list(); // add to superklass/sibling list 1804 k->process_interfaces(THREAD); // handle all "implements" declarations 1805 1806 // Now flush all code that depended on old class hierarchy. 1807 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1808 CodeCache::flush_dependents_on(k); 1809 } 1810 1811 // ---------------------------------------------------------------------------- 1812 // GC support 1813 1814 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1815 // Note: anonymous classes are not in the SD. 1816 bool SystemDictionary::do_unloading(GCTimer* gc_timer) { 1817 1818 bool unloading_occurred; 1819 bool is_concurrent = !SafepointSynchronize::is_at_safepoint(); 1820 { 1821 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1822 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks. 1823 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1824 unloading_occurred = ClassLoaderDataGraph::do_unloading(); 1825 if (unloading_occurred) { 1826 MutexLockerEx ml2(is_concurrent ? Module_lock : NULL); 1827 JFR_ONLY(Jfr::on_unloading_classes();) 1828 1829 MutexLockerEx ml1(is_concurrent ? SystemDictionary_lock : NULL); 1830 ClassLoaderDataGraph::clean_module_and_package_info(); 1831 constraints()->purge_loader_constraints(); 1832 resolution_errors()->purge_resolution_errors(); 1833 } 1834 } 1835 1836 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer); 1837 // Trigger cleaning the ResolvedMethodTable even if no unloading occurred. 1838 ResolvedMethodTable::trigger_cleanup(); 1839 1840 if (unloading_occurred) { 1841 SymbolTable::trigger_cleanup(); 1842 1843 // Oops referenced by the protection domain cache table may get unreachable independently 1844 // of the class loader (eg. cached protection domain oops). So we need to 1845 // explicitly unlink them here. 1846 // All protection domain oops are linked to the caller class, so if nothing 1847 // unloads, this is not needed. 1848 _pd_cache_table->trigger_cleanup(); 1849 } 1850 1851 return unloading_occurred; 1852 } 1853 1854 void SystemDictionary::oops_do(OopClosure* f) { 1855 f->do_oop(&_java_system_loader); 1856 f->do_oop(&_java_platform_loader); 1857 f->do_oop(&_system_loader_lock_obj); 1858 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1859 1860 // Visit extra methods 1861 invoke_method_table()->oops_do(f); 1862 } 1863 1864 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1865 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1866 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1867 it->push(well_known_klass_addr((WKID)id)); 1868 } 1869 } 1870 1871 void SystemDictionary::methods_do(void f(Method*)) { 1872 // Walk methods in loaded classes 1873 MutexLocker ml(ClassLoaderDataGraph_lock); 1874 ClassLoaderDataGraph::methods_do(f); 1875 // Walk method handle intrinsics 1876 invoke_method_table()->methods_do(f); 1877 } 1878 1879 // ---------------------------------------------------------------------------- 1880 // Initialization 1881 1882 void SystemDictionary::initialize(TRAPS) { 1883 // Allocate arrays 1884 _placeholders = new PlaceholderTable(_placeholder_table_size); 1885 _number_of_modifications = 0; 1886 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1887 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1888 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1889 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 1890 1891 // Allocate private object used as system class loader lock 1892 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1893 // Initialize basic classes 1894 resolve_well_known_classes(CHECK); 1895 } 1896 1897 // Compact table of directions on the initialization of klasses: 1898 static const short wk_init_info[] = { 1899 #define WK_KLASS_INIT_INFO(name, symbol) \ 1900 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)), 1901 1902 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1903 #undef WK_KLASS_INIT_INFO 1904 0 1905 }; 1906 1907 #ifdef ASSERT 1908 bool SystemDictionary::is_well_known_klass(Symbol* class_name) { 1909 int sid; 1910 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) { 1911 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1912 if (class_name == symbol) { 1913 return true; 1914 } 1915 } 1916 return false; 1917 } 1918 #endif 1919 1920 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) { 1921 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1922 int sid = wk_init_info[id - FIRST_WKID]; 1923 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1924 InstanceKlass** klassp = &_well_known_klasses[id]; 1925 1926 1927 #if INCLUDE_JVMCI 1928 if (id >= FIRST_JVMCI_WKID) { 1929 assert(EnableJVMCI, "resolve JVMCI classes only when EnableJVMCI is true"); 1930 } 1931 #endif 1932 1933 if ((*klassp) == NULL) { 1934 Klass* k = resolve_or_fail(symbol, true, CHECK_0); 1935 (*klassp) = InstanceKlass::cast(k); 1936 } 1937 return ((*klassp) != NULL); 1938 } 1939 1940 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1941 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1942 for (int id = (int)start_id; id < (int)limit_id; id++) { 1943 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1944 resolve_wk_klass((WKID)id, CHECK); 1945 } 1946 1947 // move the starting value forward to the limit: 1948 start_id = limit_id; 1949 } 1950 1951 void SystemDictionary::resolve_well_known_classes(TRAPS) { 1952 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once"); 1953 1954 // Create the ModuleEntry for java.base. This call needs to be done here, 1955 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 1956 ClassLoader::classLoader_init2(CHECK); 1957 1958 // Preload commonly used klasses 1959 WKID scan = FIRST_WKID; 1960 // first do Object, then String, Class 1961 #if INCLUDE_CDS 1962 if (UseSharedSpaces) { 1963 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1964 1965 // It's unsafe to access the archived heap regions before they 1966 // are fixed up, so we must do the fixup as early as possible 1967 // before the archived java objects are accessed by functions 1968 // such as java_lang_Class::restore_archived_mirror and 1969 // ConstantPool::restore_unshareable_info (restores the archived 1970 // resolved_references array object). 1971 // 1972 // HeapShared::fixup_mapped_heap_regions() fills the empty 1973 // spaces in the archived heap regions and may use 1974 // SystemDictionary::Object_klass(), so we can do this only after 1975 // Object_klass is resolved. See the above resolve_wk_klasses_through() 1976 // call. No mirror objects are accessed/restored in the above call. 1977 // Mirrors are restored after java.lang.Class is loaded. 1978 HeapShared::fixup_mapped_heap_regions(); 1979 1980 // Initialize the constant pool for the Object_class 1981 assert(Object_klass()->is_shared(), "must be"); 1982 Object_klass()->constants()->restore_unshareable_info(CHECK); 1983 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1984 } else 1985 #endif 1986 { 1987 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1988 } 1989 1990 // Calculate offsets for String and Class classes since they are loaded and 1991 // can be used after this point. 1992 java_lang_String::compute_offsets(); 1993 java_lang_Class::compute_offsets(); 1994 1995 // Fixup mirrors for classes loaded before java.lang.Class. 1996 // These calls iterate over the objects currently in the perm gen 1997 // so calling them at this point is matters (not before when there 1998 // are fewer objects and not later after there are more objects 1999 // in the perm gen. 2000 Universe::initialize_basic_type_mirrors(CHECK); 2001 Universe::fixup_mirrors(CHECK); 2002 2003 // do a bunch more: 2004 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2005 2006 // Preload ref klasses and set reference types 2007 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2008 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2009 2010 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2011 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2012 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2013 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2014 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2015 2016 // JSR 292 classes 2017 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2018 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2019 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK); 2020 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK); 2021 WKID last = NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID); 2022 resolve_wk_klasses_until(last, scan, CHECK); 2023 2024 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2025 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2026 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2027 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2028 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2029 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2030 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2031 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2032 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2033 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2034 2035 { // Compute whether we should use checkPackageAccess or NOT 2036 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2037 _has_checkPackageAccess = (method != NULL); 2038 } 2039 2040 #ifdef ASSERT 2041 if (UseSharedSpaces) { 2042 assert(JvmtiExport::is_early_phase(), 2043 "All well known classes must be resolved in JVMTI early phase"); 2044 for (int i = FIRST_WKID; i < last; i++) { 2045 InstanceKlass* k = _well_known_klasses[i]; 2046 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook"); 2047 } 2048 } 2049 #endif 2050 } 2051 2052 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2053 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2054 BasicType SystemDictionary::box_klass_type(Klass* k) { 2055 assert(k != NULL, ""); 2056 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2057 if (_box_klasses[i] == k) 2058 return (BasicType)i; 2059 } 2060 return T_OBJECT; 2061 } 2062 2063 // Constraints on class loaders. The details of the algorithm can be 2064 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2065 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2066 // that the dictionary needs to maintain a set of contraints that 2067 // must be satisfied by all classes in the dictionary. 2068 // if defining is true, then LinkageError if already in dictionary 2069 // if initiating loader, then ok if InstanceKlass matches existing entry 2070 2071 void SystemDictionary::check_constraints(unsigned int d_hash, 2072 InstanceKlass* k, 2073 Handle class_loader, 2074 bool defining, 2075 TRAPS) { 2076 ResourceMark rm(THREAD); 2077 stringStream ss; 2078 bool throwException = false; 2079 2080 { 2081 Symbol *name = k->name(); 2082 ClassLoaderData *loader_data = class_loader_data(class_loader); 2083 2084 MutexLocker mu(SystemDictionary_lock, THREAD); 2085 2086 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2087 if (check != NULL) { 2088 // If different InstanceKlass - duplicate class definition, 2089 // else - ok, class loaded by a different thread in parallel. 2090 // We should only have found it if it was done loading and ok to use. 2091 // The dictionary only holds instance classes, placeholders 2092 // also hold array classes. 2093 2094 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2095 if ((defining == true) || (k != check)) { 2096 throwException = true; 2097 ss.print("loader %s", loader_data->loader_name_and_id()); 2098 ss.print(" attempted duplicate %s definition for %s. (%s)", 2099 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true)); 2100 } else { 2101 return; 2102 } 2103 } 2104 2105 #ifdef ASSERT 2106 Symbol* ph_check = find_placeholder(name, loader_data); 2107 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2108 #endif 2109 2110 if (throwException == false) { 2111 if (constraints()->check_or_update(k, class_loader, name) == false) { 2112 throwException = true; 2113 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id()); 2114 ss.print(" wants to load %s %s.", 2115 k->external_kind(), k->external_name()); 2116 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); 2117 if (existing_klass->class_loader() != class_loader()) { 2118 ss.print(" A different %s with the same name was previously loaded by %s. (%s)", 2119 existing_klass->external_kind(), 2120 existing_klass->class_loader_data()->loader_name_and_id(), 2121 existing_klass->class_in_module_of_loader(false, true)); 2122 } else { 2123 ss.print(" (%s)", k->class_in_module_of_loader(false, true)); 2124 } 2125 } 2126 } 2127 } 2128 2129 // Throw error now if needed (cannot throw while holding 2130 // SystemDictionary_lock because of rank ordering) 2131 if (throwException == true) { 2132 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); 2133 } 2134 } 2135 2136 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2137 // have been called. 2138 void SystemDictionary::update_dictionary(unsigned int d_hash, 2139 int p_index, unsigned int p_hash, 2140 InstanceKlass* k, 2141 Handle class_loader, 2142 TRAPS) { 2143 // Compile_lock prevents systemDictionary updates during compilations 2144 assert_locked_or_safepoint(Compile_lock); 2145 Symbol* name = k->name(); 2146 ClassLoaderData *loader_data = class_loader_data(class_loader); 2147 2148 { 2149 MutexLocker mu1(SystemDictionary_lock, THREAD); 2150 2151 // See whether biased locking is enabled and if so set it for this 2152 // klass. 2153 // Note that this must be done past the last potential blocking 2154 // point / safepoint. We enable biased locking lazily using a 2155 // VM_Operation to iterate the SystemDictionary and installing the 2156 // biasable mark word into each InstanceKlass's prototype header. 2157 // To avoid race conditions where we accidentally miss enabling the 2158 // optimization for one class in the process of being added to the 2159 // dictionary, we must not safepoint after the test of 2160 // BiasedLocking::enabled(). 2161 if (UseBiasedLocking && BiasedLocking::enabled()) { 2162 // Set biased locking bit for all loaded classes; it will be 2163 // cleared if revocation occurs too often for this type 2164 // NOTE that we must only do this when the class is initally 2165 // defined, not each time it is referenced from a new class loader 2166 if (oopDesc::equals(k->class_loader(), class_loader())) { 2167 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2168 } 2169 } 2170 2171 // Make a new dictionary entry. 2172 Dictionary* dictionary = loader_data->dictionary(); 2173 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2174 if (sd_check == NULL) { 2175 dictionary->add_klass(d_hash, name, k); 2176 2177 notice_modification(); 2178 } 2179 #ifdef ASSERT 2180 sd_check = find_class(d_hash, name, dictionary); 2181 assert (sd_check != NULL, "should have entry in dictionary"); 2182 // Note: there may be a placeholder entry: for circularity testing 2183 // or for parallel defines 2184 #endif 2185 SystemDictionary_lock->notify_all(); 2186 } 2187 } 2188 2189 2190 // Try to find a class name using the loader constraints. The 2191 // loader constraints might know about a class that isn't fully loaded 2192 // yet and these will be ignored. 2193 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2194 Symbol* class_name, Handle class_loader, TRAPS) { 2195 2196 // First see if it has been loaded directly. 2197 // Force the protection domain to be null. (This removes protection checks.) 2198 Handle no_protection_domain; 2199 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2200 no_protection_domain, CHECK_NULL); 2201 if (klass != NULL) 2202 return klass; 2203 2204 // Now look to see if it has been loaded elsewhere, and is subject to 2205 // a loader constraint that would require this loader to return the 2206 // klass that is already loaded. 2207 if (FieldType::is_array(class_name)) { 2208 // For array classes, their Klass*s are not kept in the 2209 // constraint table. The element Klass*s are. 2210 FieldArrayInfo fd; 2211 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2212 if (t != T_OBJECT) { 2213 klass = Universe::typeArrayKlassObj(t); 2214 } else { 2215 MutexLocker mu(SystemDictionary_lock, THREAD); 2216 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2217 } 2218 // If element class already loaded, allocate array klass 2219 if (klass != NULL) { 2220 klass = klass->array_klass_or_null(fd.dimension()); 2221 } 2222 } else { 2223 MutexLocker mu(SystemDictionary_lock, THREAD); 2224 // Non-array classes are easy: simply check the constraint table. 2225 klass = constraints()->find_constrained_klass(class_name, class_loader); 2226 } 2227 2228 return klass; 2229 } 2230 2231 2232 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2233 Handle class_loader1, 2234 Handle class_loader2, 2235 Thread* THREAD) { 2236 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2237 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2238 2239 Symbol* constraint_name = NULL; 2240 // Needs to be in same scope as constraint_name in case a Symbol is created and 2241 // assigned to constraint_name. 2242 FieldArrayInfo fd; 2243 if (!FieldType::is_array(class_name)) { 2244 constraint_name = class_name; 2245 } else { 2246 // For array classes, their Klass*s are not kept in the 2247 // constraint table. The element classes are. 2248 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2249 // primitive types always pass 2250 if (t != T_OBJECT) { 2251 return true; 2252 } else { 2253 constraint_name = fd.object_key(); 2254 } 2255 } 2256 2257 Dictionary* dictionary1 = loader_data1->dictionary(); 2258 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2259 2260 Dictionary* dictionary2 = loader_data2->dictionary(); 2261 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2262 2263 { 2264 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2265 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2266 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2267 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2268 klass2, class_loader2); 2269 } 2270 } 2271 2272 // Add entry to resolution error table to record the error when the first 2273 // attempt to resolve a reference to a class has failed. 2274 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2275 Symbol* error, Symbol* message) { 2276 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2277 int index = resolution_errors()->hash_to_index(hash); 2278 { 2279 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2280 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2281 } 2282 } 2283 2284 // Delete a resolution error for RedefineClasses for a constant pool is going away 2285 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2286 resolution_errors()->delete_entry(pool); 2287 } 2288 2289 // Lookup resolution error table. Returns error if found, otherwise NULL. 2290 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2291 Symbol** message) { 2292 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2293 int index = resolution_errors()->hash_to_index(hash); 2294 { 2295 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2296 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2297 if (entry != NULL) { 2298 *message = entry->message(); 2299 return entry->error(); 2300 } else { 2301 return NULL; 2302 } 2303 } 2304 } 2305 2306 2307 // Signature constraints ensure that callers and callees agree about 2308 // the meaning of type names in their signatures. This routine is the 2309 // intake for constraints. It collects them from several places: 2310 // 2311 // * LinkResolver::resolve_method (if check_access is true) requires 2312 // that the resolving class (the caller) and the defining class of 2313 // the resolved method (the callee) agree on each type in the 2314 // method's signature. 2315 // 2316 // * LinkResolver::resolve_interface_method performs exactly the same 2317 // checks. 2318 // 2319 // * LinkResolver::resolve_field requires that the constant pool 2320 // attempting to link to a field agree with the field's defining 2321 // class about the type of the field signature. 2322 // 2323 // * klassVtable::initialize_vtable requires that, when a class 2324 // overrides a vtable entry allocated by a superclass, that the 2325 // overriding method (i.e., the callee) agree with the superclass 2326 // on each type in the method's signature. 2327 // 2328 // * klassItable::initialize_itable requires that, when a class fills 2329 // in its itables, for each non-abstract method installed in an 2330 // itable, the method (i.e., the callee) agree with the interface 2331 // on each type in the method's signature. 2332 // 2333 // All those methods have a boolean (check_access, checkconstraints) 2334 // which turns off the checks. This is used from specialized contexts 2335 // such as bootstrapping, dumping, and debugging. 2336 // 2337 // No direct constraint is placed between the class and its 2338 // supertypes. Constraints are only placed along linked relations 2339 // between callers and callees. When a method overrides or implements 2340 // an abstract method in a supertype (superclass or interface), the 2341 // constraints are placed as if the supertype were the caller to the 2342 // overriding method. (This works well, since callers to the 2343 // supertype have already established agreement between themselves and 2344 // the supertype.) As a result of all this, a class can disagree with 2345 // its supertype about the meaning of a type name, as long as that 2346 // class neither calls a relevant method of the supertype, nor is 2347 // called (perhaps via an override) from the supertype. 2348 // 2349 // 2350 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2351 // 2352 // Make sure all class components (including arrays) in the given 2353 // signature will be resolved to the same class in both loaders. 2354 // Returns the name of the type that failed a loader constraint check, or 2355 // NULL if no constraint failed. No exception except OOME is thrown. 2356 // Arrays are not added to the loader constraint table, their elements are. 2357 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2358 Handle loader1, Handle loader2, 2359 bool is_method, TRAPS) { 2360 // Nothing to do if loaders are the same. 2361 if (oopDesc::equals(loader1(), loader2())) { 2362 return NULL; 2363 } 2364 2365 SignatureStream sig_strm(signature, is_method); 2366 while (!sig_strm.is_done()) { 2367 if (sig_strm.is_object()) { 2368 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2369 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2370 return sig; 2371 } 2372 } 2373 sig_strm.next(); 2374 } 2375 return NULL; 2376 } 2377 2378 2379 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2380 Symbol* signature, 2381 TRAPS) { 2382 methodHandle empty; 2383 assert(MethodHandles::is_signature_polymorphic(iid) && 2384 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2385 iid != vmIntrinsics::_invokeGeneric, 2386 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2387 2388 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2389 int index = invoke_method_table()->hash_to_index(hash); 2390 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2391 methodHandle m; 2392 if (spe == NULL || spe->method() == NULL) { 2393 spe = NULL; 2394 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2395 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2396 if (!Arguments::is_interpreter_only()) { 2397 // Generate a compiled form of the MH intrinsic. 2398 AdapterHandlerLibrary::create_native_wrapper(m); 2399 // Check if have the compiled code. 2400 if (!m->has_compiled_code()) { 2401 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2402 "Out of space in CodeCache for method handle intrinsic", empty); 2403 } 2404 } 2405 // Now grab the lock. We might have to throw away the new method, 2406 // if a racing thread has managed to install one at the same time. 2407 { 2408 MutexLocker ml(SystemDictionary_lock, THREAD); 2409 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2410 if (spe == NULL) 2411 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2412 if (spe->method() == NULL) 2413 spe->set_method(m()); 2414 } 2415 } 2416 2417 assert(spe != NULL && spe->method() != NULL, ""); 2418 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2419 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2420 "MH intrinsic invariant"); 2421 return spe->method(); 2422 } 2423 2424 // Helper for unpacking the return value from linkMethod and linkCallSite. 2425 static methodHandle unpack_method_and_appendix(Handle mname, 2426 Klass* accessing_klass, 2427 objArrayHandle appendix_box, 2428 Handle* appendix_result, 2429 TRAPS) { 2430 methodHandle empty; 2431 if (mname.not_null()) { 2432 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2433 if (m != NULL) { 2434 oop appendix = appendix_box->obj_at(0); 2435 if (TraceMethodHandles) { 2436 #ifndef PRODUCT 2437 ttyLocker ttyl; 2438 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2439 m->print(); 2440 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2441 tty->cr(); 2442 #endif //PRODUCT 2443 } 2444 (*appendix_result) = Handle(THREAD, appendix); 2445 // the target is stored in the cpCache and if a reference to this 2446 // MemberName is dropped we need a way to make sure the 2447 // class_loader containing this method is kept alive. 2448 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2449 this_key->record_dependency(m->method_holder()); 2450 return methodHandle(THREAD, m); 2451 } 2452 } 2453 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2454 return empty; 2455 } 2456 2457 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2458 Symbol* name, 2459 Symbol* signature, 2460 Klass* accessing_klass, 2461 Handle *appendix_result, 2462 Handle *method_type_result, 2463 TRAPS) { 2464 methodHandle empty; 2465 assert(THREAD->can_call_java() ,""); 2466 Handle method_type = 2467 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2468 2469 int ref_kind = JVM_REF_invokeVirtual; 2470 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2471 Handle name_str (THREAD, name_oop); 2472 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2473 assert(appendix_box->obj_at(0) == NULL, ""); 2474 2475 // This should not happen. JDK code should take care of that. 2476 if (accessing_klass == NULL || method_type.is_null()) { 2477 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2478 } 2479 2480 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2481 JavaCallArguments args; 2482 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2483 args.push_int(ref_kind); 2484 args.push_oop(Handle(THREAD, klass->java_mirror())); 2485 args.push_oop(name_str); 2486 args.push_oop(method_type); 2487 args.push_oop(appendix_box); 2488 JavaValue result(T_OBJECT); 2489 JavaCalls::call_static(&result, 2490 SystemDictionary::MethodHandleNatives_klass(), 2491 vmSymbols::linkMethod_name(), 2492 vmSymbols::linkMethod_signature(), 2493 &args, CHECK_(empty)); 2494 Handle mname(THREAD, (oop) result.get_jobject()); 2495 (*method_type_result) = method_type; 2496 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2497 } 2498 2499 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2500 // We must ensure that all class loaders everywhere will reach this class, for any client. 2501 // This is a safe bet for public classes in java.lang, such as Object and String. 2502 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2503 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2504 static bool is_always_visible_class(oop mirror) { 2505 Klass* klass = java_lang_Class::as_Klass(mirror); 2506 if (klass->is_objArray_klass()) { 2507 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2508 } 2509 if (klass->is_typeArray_klass()) { 2510 return true; // primitive array 2511 } 2512 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2513 return klass->is_public() && 2514 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2515 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2516 } 2517 2518 2519 // Return the Java mirror (java.lang.Class instance) for a single-character 2520 // descriptor. This result, when available, is the same as produced by the 2521 // heavier API point of the same name that takes a Symbol. 2522 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2523 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2524 } 2525 2526 // Find or construct the Java mirror (java.lang.Class instance) for a 2527 // for the given field type signature, as interpreted relative to the 2528 // given class loader. Handles primitives, void, references, arrays, 2529 // and all other reflectable types, except method types. 2530 // N.B. Code in reflection should use this entry point. 2531 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2532 Klass* accessing_klass, 2533 Handle class_loader, 2534 Handle protection_domain, 2535 SignatureStream::FailureMode failure_mode, 2536 TRAPS) { 2537 Handle empty; 2538 2539 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2540 "one or the other, or perhaps neither"); 2541 2542 Symbol* type = signature; 2543 2544 // What we have here must be a valid field descriptor, 2545 // and all valid field descriptors are supported. 2546 // Produce the same java.lang.Class that reflection reports. 2547 if (type->utf8_length() == 1) { 2548 2549 // It's a primitive. (Void has a primitive mirror too.) 2550 char ch = type->char_at(0); 2551 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2552 return Handle(THREAD, find_java_mirror_for_type(ch)); 2553 2554 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2555 2556 // It's a reference type. 2557 if (accessing_klass != NULL) { 2558 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2559 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2560 } 2561 Klass* constant_type_klass; 2562 if (failure_mode == SignatureStream::ReturnNull) { 2563 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2564 CHECK_(empty)); 2565 } else { 2566 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2567 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2568 throw_error, CHECK_(empty)); 2569 } 2570 if (constant_type_klass == NULL) { 2571 return Handle(); // report failure this way 2572 } 2573 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2574 2575 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2576 if (accessing_klass != NULL) { 2577 Klass* sel_klass = constant_type_klass; 2578 bool fold_type_to_class = true; 2579 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2580 fold_type_to_class, CHECK_(empty)); 2581 } 2582 2583 return mirror; 2584 2585 } 2586 2587 // Fall through to an error. 2588 assert(false, "unsupported mirror syntax"); 2589 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2590 } 2591 2592 2593 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2594 // signature, as interpreted relative to the given class loader. 2595 // Because of class loader constraints, all method handle usage must be 2596 // consistent with this loader. 2597 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2598 Klass* accessing_klass, 2599 TRAPS) { 2600 Handle empty; 2601 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2602 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2603 int index = invoke_method_table()->hash_to_index(hash); 2604 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2605 if (spe != NULL && spe->method_type() != NULL) { 2606 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2607 return Handle(THREAD, spe->method_type()); 2608 } else if (!THREAD->can_call_java()) { 2609 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2610 return Handle(); // do not attempt from within compiler, unless it was cached 2611 } 2612 2613 Handle class_loader, protection_domain; 2614 if (accessing_klass != NULL) { 2615 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2616 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2617 } 2618 bool can_be_cached = true; 2619 int npts = ArgumentCount(signature).size(); 2620 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2621 int arg = 0; 2622 Handle rt; // the return type from the signature 2623 ResourceMark rm(THREAD); 2624 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2625 oop mirror = NULL; 2626 if (can_be_cached) { 2627 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2628 mirror = ss.as_java_mirror(Handle(), Handle(), 2629 SignatureStream::ReturnNull, CHECK_(empty)); 2630 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2631 // Fall back to accessing_klass context. 2632 can_be_cached = false; 2633 } 2634 } 2635 if (!can_be_cached) { 2636 // Resolve, throwing a real error if it doesn't work. 2637 mirror = ss.as_java_mirror(class_loader, protection_domain, 2638 SignatureStream::NCDFError, CHECK_(empty)); 2639 } 2640 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string()); 2641 if (ss.at_return_type()) 2642 rt = Handle(THREAD, mirror); 2643 else 2644 pts->obj_at_put(arg++, mirror); 2645 2646 // Check accessibility. 2647 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2648 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2649 mirror = NULL; // safety 2650 // Emulate ConstantPool::verify_constant_pool_resolve. 2651 bool fold_type_to_class = true; 2652 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2653 fold_type_to_class, CHECK_(empty)); 2654 } 2655 } 2656 assert(arg == npts, ""); 2657 2658 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2659 JavaCallArguments args(Handle(THREAD, rt())); 2660 args.push_oop(pts); 2661 JavaValue result(T_OBJECT); 2662 JavaCalls::call_static(&result, 2663 SystemDictionary::MethodHandleNatives_klass(), 2664 vmSymbols::findMethodHandleType_name(), 2665 vmSymbols::findMethodHandleType_signature(), 2666 &args, CHECK_(empty)); 2667 Handle method_type(THREAD, (oop) result.get_jobject()); 2668 2669 if (can_be_cached) { 2670 // We can cache this MethodType inside the JVM. 2671 MutexLocker ml(SystemDictionary_lock, THREAD); 2672 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2673 if (spe == NULL) 2674 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2675 if (spe->method_type() == NULL) { 2676 spe->set_method_type(method_type()); 2677 } 2678 } 2679 2680 // report back to the caller with the MethodType 2681 return method_type; 2682 } 2683 2684 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2685 Klass* accessing_klass, 2686 TRAPS) { 2687 Handle empty; 2688 ResourceMark rm(THREAD); 2689 SignatureStream ss(signature, /*is_method=*/ false); 2690 if (!ss.is_done()) { 2691 Handle class_loader, protection_domain; 2692 if (accessing_klass != NULL) { 2693 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2694 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2695 } 2696 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2697 ss.next(); 2698 if (ss.is_done()) { 2699 return Handle(THREAD, mirror); 2700 } 2701 } 2702 return empty; 2703 } 2704 2705 // Ask Java code to find or construct a method handle constant. 2706 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2707 int ref_kind, //e.g., JVM_REF_invokeVirtual 2708 Klass* callee, 2709 Symbol* name, 2710 Symbol* signature, 2711 TRAPS) { 2712 Handle empty; 2713 if (caller == NULL) { 2714 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2715 } 2716 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2717 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2718 2719 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2720 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2721 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2722 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2723 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2724 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2725 2726 if (ref_kind == JVM_REF_invokeVirtual && 2727 MethodHandles::is_signature_polymorphic_public_name(callee, name)) { 2728 // Skip resolution for public signature polymorphic methods such as 2729 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle 2730 // They require appendix argument which MemberName resolution doesn't handle. 2731 // There's special logic on JDK side to handle them 2732 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2733 } else { 2734 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); 2735 } 2736 2737 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2738 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2739 2740 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2741 JavaCallArguments args; 2742 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2743 args.push_int(ref_kind); 2744 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2745 args.push_oop(name_str); 2746 args.push_oop(type); 2747 JavaValue result(T_OBJECT); 2748 JavaCalls::call_static(&result, 2749 SystemDictionary::MethodHandleNatives_klass(), 2750 vmSymbols::linkMethodHandleConstant_name(), 2751 vmSymbols::linkMethodHandleConstant_signature(), 2752 &args, CHECK_(empty)); 2753 return Handle(THREAD, (oop) result.get_jobject()); 2754 } 2755 2756 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry 2757 Handle SystemDictionary::link_dynamic_constant(Klass* caller, 2758 int condy_index, 2759 Handle bootstrap_specifier, 2760 Symbol* name, 2761 Symbol* type, 2762 TRAPS) { 2763 Handle empty; 2764 Handle bsm, info; 2765 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2766 bsm = bootstrap_specifier; 2767 } else { 2768 assert(bootstrap_specifier->is_objArray(), ""); 2769 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2770 assert(args->length() == 2, ""); 2771 bsm = Handle(THREAD, args->obj_at(0)); 2772 info = Handle(THREAD, args->obj_at(1)); 2773 } 2774 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2775 "caller must supply a valid BSM"); 2776 2777 // This should not happen. JDK code should take care of that. 2778 if (caller == NULL) { 2779 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); 2780 } 2781 2782 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2783 2784 // Resolve the constant type in the context of the caller class 2785 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, 2786 CHECK_(empty)); 2787 2788 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) 2789 JavaCallArguments args; 2790 args.push_oop(Handle(THREAD, caller->java_mirror())); 2791 args.push_int(condy_index); 2792 args.push_oop(bsm); 2793 args.push_oop(constant_name); 2794 args.push_oop(type_mirror); 2795 args.push_oop(info); 2796 JavaValue result(T_OBJECT); 2797 JavaCalls::call_static(&result, 2798 SystemDictionary::MethodHandleNatives_klass(), 2799 vmSymbols::linkDynamicConstant_name(), 2800 vmSymbols::linkDynamicConstant_signature(), 2801 &args, CHECK_(empty)); 2802 2803 return Handle(THREAD, (oop) result.get_jobject()); 2804 } 2805 2806 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2807 // name and signature, as interpreted relative to the given class loader. 2808 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2809 int indy_index, 2810 Handle bootstrap_specifier, 2811 Symbol* name, 2812 Symbol* type, 2813 Handle *appendix_result, 2814 Handle *method_type_result, 2815 TRAPS) { 2816 methodHandle empty; 2817 Handle bsm, info; 2818 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2819 bsm = bootstrap_specifier; 2820 } else { 2821 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2822 assert(args->length() == 2, ""); 2823 bsm = Handle(THREAD, args->obj_at(0)); 2824 info = Handle(THREAD, args->obj_at(1)); 2825 } 2826 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2827 "caller must supply a valid BSM"); 2828 2829 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2830 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2831 2832 // This should not happen. JDK code should take care of that. 2833 if (caller == NULL || method_type.is_null()) { 2834 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2835 } 2836 2837 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2838 assert(appendix_box->obj_at(0) == NULL, ""); 2839 2840 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2841 JavaCallArguments args; 2842 args.push_oop(Handle(THREAD, caller->java_mirror())); 2843 args.push_int(indy_index); 2844 args.push_oop(bsm); 2845 args.push_oop(method_name); 2846 args.push_oop(method_type); 2847 args.push_oop(info); 2848 args.push_oop(appendix_box); 2849 JavaValue result(T_OBJECT); 2850 JavaCalls::call_static(&result, 2851 SystemDictionary::MethodHandleNatives_klass(), 2852 vmSymbols::linkCallSite_name(), 2853 vmSymbols::linkCallSite_signature(), 2854 &args, CHECK_(empty)); 2855 Handle mname(THREAD, (oop) result.get_jobject()); 2856 (*method_type_result) = method_type; 2857 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2858 } 2859 2860 // Protection domain cache table handling 2861 2862 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2863 return _pd_cache_table->get(protection_domain); 2864 } 2865 2866 // ---------------------------------------------------------------------------- 2867 2868 void SystemDictionary::print_on(outputStream *st) { 2869 CDS_ONLY(SystemDictionaryShared::print_on(st)); 2870 GCMutexLocker mu(SystemDictionary_lock); 2871 2872 ClassLoaderDataGraph::print_dictionary(st); 2873 2874 // Placeholders 2875 placeholders()->print_on(st); 2876 st->cr(); 2877 2878 // loader constraints - print under SD_lock 2879 constraints()->print_on(st); 2880 st->cr(); 2881 2882 _pd_cache_table->print_on(st); 2883 st->cr(); 2884 } 2885 2886 void SystemDictionary::verify() { 2887 guarantee(constraints() != NULL, 2888 "Verify of loader constraints failed"); 2889 guarantee(placeholders()->number_of_entries() >= 0, 2890 "Verify of placeholders failed"); 2891 2892 GCMutexLocker mu(SystemDictionary_lock); 2893 2894 // Verify dictionary 2895 ClassLoaderDataGraph::verify_dictionary(); 2896 2897 placeholders()->verify(); 2898 2899 // Verify constraint table 2900 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2901 constraints()->verify(placeholders()); 2902 2903 _pd_cache_table->verify(); 2904 } 2905 2906 void SystemDictionary::dump(outputStream *st, bool verbose) { 2907 assert_locked_or_safepoint(SystemDictionary_lock); 2908 if (verbose) { 2909 print_on(st); 2910 } else { 2911 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st)); 2912 ClassLoaderDataGraph::print_dictionary_statistics(st); 2913 placeholders()->print_table_statistics(st, "Placeholder Table"); 2914 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 2915 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 2916 } 2917 } 2918 2919 // Utility for dumping dictionaries. 2920 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 2921 DCmdWithParser(output, heap), 2922 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 2923 "BOOLEAN", false, "false") { 2924 _dcmdparser.add_dcmd_option(&_verbose); 2925 } 2926 2927 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 2928 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 2929 _verbose.value()); 2930 VMThread::execute(&dumper); 2931 } 2932 2933 int SystemDictionaryDCmd::num_arguments() { 2934 ResourceMark rm; 2935 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 2936 if (dcmd != NULL) { 2937 DCmdMark mark(dcmd); 2938 return dcmd->_dcmdparser.num_arguments(); 2939 } else { 2940 return 0; 2941 } 2942 } 2943 2944 void SystemDictionary::initialize_oop_storage() { 2945 _vm_weak_oop_storage = 2946 new OopStorage("VM Weak Oop Handles", 2947 VMWeakAlloc_lock, 2948 VMWeakActive_lock); 2949 } 2950 2951 OopStorage* SystemDictionary::vm_weak_oop_storage() { 2952 assert(_vm_weak_oop_storage != NULL, "Uninitialized"); 2953 return _vm_weak_oop_storage; 2954 }