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