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 } 153 154 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) { 155 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 156 return ClassLoaderDataGraph::find_or_create(class_loader); 157 } 158 159 // ---------------------------------------------------------------------------- 160 // Parallel class loading check 161 162 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 163 if (class_loader.is_null()) return true; 164 if (AlwaysLockClassLoader) return false; 165 return java_lang_ClassLoader::parallelCapable(class_loader()); 166 } 167 // ---------------------------------------------------------------------------- 168 // ParallelDefineClass flag does not apply to bootclass loader 169 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 170 if (class_loader.is_null()) return false; 171 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 172 return true; 173 } 174 return false; 175 } 176 177 // Returns true if the passed class loader is the builtin application class loader 178 // or a custom system class loader. A customer system class loader can be 179 // specified via -Djava.system.class.loader. 180 bool SystemDictionary::is_system_class_loader(oop class_loader) { 181 if (class_loader == NULL) { 182 return false; 183 } 184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 185 oopDesc::equals(class_loader, _java_system_loader)); 186 } 187 188 // Returns true if the passed class loader is the platform class loader. 189 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 190 if (class_loader == NULL) { 191 return false; 192 } 193 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 194 } 195 196 // ---------------------------------------------------------------------------- 197 // Resolving of classes 198 199 // Forwards to resolve_or_null 200 201 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 202 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 203 if (HAS_PENDING_EXCEPTION || klass == NULL) { 204 // can return a null klass 205 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 206 } 207 return klass; 208 } 209 210 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 211 bool throw_error, 212 Klass* klass, TRAPS) { 213 if (HAS_PENDING_EXCEPTION) { 214 // If we have a pending exception we forward it to the caller, unless throw_error is true, 215 // in which case we have to check whether the pending exception is a ClassNotFoundException, 216 // and if so convert it to a NoClassDefFoundError 217 // And chain the original ClassNotFoundException 218 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 219 ResourceMark rm(THREAD); 220 assert(klass == NULL, "Should not have result with exception pending"); 221 Handle e(THREAD, PENDING_EXCEPTION); 222 CLEAR_PENDING_EXCEPTION; 223 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 224 } else { 225 return NULL; 226 } 227 } 228 // Class not found, throw appropriate error or exception depending on value of throw_error 229 if (klass == NULL) { 230 ResourceMark rm(THREAD); 231 if (throw_error) { 232 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 233 } else { 234 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 235 } 236 } 237 return klass; 238 } 239 240 241 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 242 bool throw_error, TRAPS) 243 { 244 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 245 } 246 247 248 // Forwards to resolve_instance_class_or_null 249 250 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 251 assert(THREAD->can_call_java(), 252 "can not load classes with compiler thread: class=%s, classloader=%s", 253 class_name->as_C_string(), 254 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 255 if (FieldType::is_array(class_name)) { 256 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 257 } else if (FieldType::is_obj(class_name)) { 258 ResourceMark rm(THREAD); 259 // Ignore wrapping L and ;. 260 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 261 class_name->utf8_length() - 2, CHECK_NULL); 262 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 263 } else { 264 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 265 } 266 } 267 268 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 269 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 270 } 271 272 // Forwards to resolve_instance_class_or_null 273 274 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 275 Handle class_loader, 276 Handle protection_domain, 277 TRAPS) { 278 assert(FieldType::is_array(class_name), "must be array"); 279 Klass* k = NULL; 280 FieldArrayInfo fd; 281 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 282 // of this call 283 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 284 if (t == T_OBJECT) { 285 // naked oop "k" is OK here -- we assign back into it 286 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 287 class_loader, 288 protection_domain, 289 CHECK_NULL); 290 if (k != NULL) { 291 k = k->array_klass(fd.dimension(), CHECK_NULL); 292 } 293 } else { 294 k = Universe::typeArrayKlassObj(t); 295 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 296 } 297 return k; 298 } 299 300 301 // Must be called for any super-class or super-interface resolution 302 // during class definition to allow class circularity checking 303 // super-interface callers: 304 // parse_interfaces - for defineClass & jvmtiRedefineClasses 305 // super-class callers: 306 // ClassFileParser - for defineClass & jvmtiRedefineClasses 307 // load_shared_class - while loading a class from shared archive 308 // resolve_instance_class_or_null: 309 // via: handle_parallel_super_load 310 // when resolving a class that has an existing placeholder with 311 // a saved superclass [i.e. a defineClass is currently in progress] 312 // if another thread is trying to resolve the class, it must do 313 // super-class checks on its own thread to catch class circularity 314 // This last call is critical in class circularity checking for cases 315 // where classloading is delegated to different threads and the 316 // classloader lock is released. 317 // Take the case: Base->Super->Base 318 // 1. If thread T1 tries to do a defineClass of class Base 319 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 320 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 321 // so it tries to load Super 322 // 3. If we load the class internally, or user classloader uses same thread 323 // loadClassFromxxx or defineClass via parseClassFile Super ... 324 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 325 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 326 // 3.4 calls resolve_super_or_fail Base 327 // 3.5 finds T1,Base -> throws class circularity 328 //OR 4. If T2 tries to resolve Super via defineClass Super ... 329 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 330 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 331 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 332 // 4.4 finds T2, Super -> throws class circularity 333 // Must be called, even if superclass is null, since this is 334 // where the placeholder entry is created which claims this 335 // thread is loading this class/classloader. 336 // Be careful when modifying this code: once you have run 337 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 338 // you need to find_and_remove it before returning. 339 // So be careful to not exit with a CHECK_ macro betweeen these calls. 340 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 341 Symbol* class_name, 342 Handle class_loader, 343 Handle protection_domain, 344 bool is_superclass, 345 TRAPS) { 346 #if INCLUDE_CDS 347 if (DumpSharedSpaces) { 348 // Special processing for CDS dump time. 349 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 350 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 351 if (k) { 352 return k; 353 } 354 } 355 #endif // INCLUDE_CDS 356 357 // Double-check, if child class is already loaded, just return super-class,interface 358 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 359 // dictionary. 360 // Make sure there's a placeholder for the *child* before resolving. 361 // Used as a claim that this thread is currently loading superclass/classloader 362 // Used here for ClassCircularity checks and also for heap verification 363 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 364 // Must check ClassCircularity before checking if super class is already loaded. 365 // 366 // We might not already have a placeholder if this child_name was 367 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 368 // the name of the class might not be known until the stream is actually 369 // parsed. 370 // Bugs 4643874, 4715493 371 372 ClassLoaderData* loader_data = class_loader_data(class_loader); 373 Dictionary* dictionary = loader_data->dictionary(); 374 unsigned int d_hash = dictionary->compute_hash(child_name); 375 unsigned int p_hash = placeholders()->compute_hash(child_name); 376 int p_index = placeholders()->hash_to_index(p_hash); 377 // can't throw error holding a lock 378 bool child_already_loaded = false; 379 bool throw_circularity_error = false; 380 { 381 MutexLocker mu(SystemDictionary_lock, THREAD); 382 Klass* childk = find_class(d_hash, child_name, dictionary); 383 Klass* quicksuperk; 384 // to support // loading: if child done loading, just return superclass 385 // if class_name, & class_loader don't match: 386 // if initial define, SD update will give LinkageError 387 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 388 // so we don't throw an exception here. 389 // see: nsk redefclass014 & java.lang.instrument Instrument032 390 if ((childk != NULL ) && (is_superclass) && 391 ((quicksuperk = childk->super()) != NULL) && 392 393 ((quicksuperk->name() == class_name) && 394 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) { 395 return quicksuperk; 396 } else { 397 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 398 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 399 throw_circularity_error = true; 400 } 401 } 402 if (!throw_circularity_error) { 403 // Be careful not to exit resolve_super 404 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 405 } 406 } 407 if (throw_circularity_error) { 408 ResourceMark rm(THREAD); 409 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 410 } 411 412 // java.lang.Object should have been found above 413 assert(class_name != NULL, "null super class for resolving"); 414 // Resolve the super class or interface, check results on return 415 Klass* superk = SystemDictionary::resolve_or_null(class_name, 416 class_loader, 417 protection_domain, 418 THREAD); 419 420 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 421 // It is no longer necessary to keep the placeholder table alive until update_dictionary 422 // or error. GC used to walk the placeholder table as strong roots. 423 // The instanceKlass is kept alive because the class loader is on the stack, 424 // which keeps the loader_data alive, as well as all instanceKlasses in 425 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 426 { 427 MutexLocker mu(SystemDictionary_lock, THREAD); 428 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 429 SystemDictionary_lock->notify_all(); 430 } 431 if (HAS_PENDING_EXCEPTION || superk == NULL) { 432 // can null superk 433 superk = handle_resolution_exception(class_name, true, superk, THREAD); 434 } 435 436 return superk; 437 } 438 439 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 440 Handle class_loader, 441 Handle protection_domain, 442 TRAPS) { 443 if(!has_checkPackageAccess()) return; 444 445 // Now we have to call back to java to check if the initating class has access 446 JavaValue result(T_VOID); 447 LogTarget(Debug, protectiondomain) lt; 448 if (lt.is_enabled()) { 449 ResourceMark rm; 450 // Print out trace information 451 LogStream ls(lt); 452 ls.print_cr("Checking package access"); 453 ls.print("class loader: "); class_loader()->print_value_on(&ls); 454 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls); 455 ls.print(" loading: "); klass->print_value_on(&ls); 456 ls.cr(); 457 } 458 459 // This handle and the class_loader handle passed in keeps this class from 460 // being unloaded through several GC points. 461 // The class_loader handle passed in is the initiating loader. 462 Handle mirror(THREAD, klass->java_mirror()); 463 464 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 465 JavaCalls::call_special(&result, 466 class_loader, 467 system_loader, 468 vmSymbols::checkPackageAccess_name(), 469 vmSymbols::class_protectiondomain_signature(), 470 mirror, 471 protection_domain, 472 THREAD); 473 474 if (HAS_PENDING_EXCEPTION) { 475 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 476 } else { 477 log_debug(protectiondomain)("granted"); 478 } 479 480 if (HAS_PENDING_EXCEPTION) return; 481 482 // If no exception has been thrown, we have validated the protection domain 483 // Insert the protection domain of the initiating class into the set. 484 { 485 ClassLoaderData* loader_data = class_loader_data(class_loader); 486 Dictionary* dictionary = loader_data->dictionary(); 487 488 Symbol* kn = klass->name(); 489 unsigned int d_hash = dictionary->compute_hash(kn); 490 491 MutexLocker mu(SystemDictionary_lock, THREAD); 492 int d_index = dictionary->hash_to_index(d_hash); 493 dictionary->add_protection_domain(d_index, d_hash, klass, 494 protection_domain, THREAD); 495 } 496 } 497 498 // We only get here if this thread finds that another thread 499 // has already claimed the placeholder token for the current operation, 500 // but that other thread either never owned or gave up the 501 // object lock 502 // Waits on SystemDictionary_lock to indicate placeholder table updated 503 // On return, caller must recheck placeholder table state 504 // 505 // We only get here if 506 // 1) custom classLoader, i.e. not bootstrap classloader 507 // 2) custom classLoader has broken the class loader objectLock 508 // so another thread got here in parallel 509 // 510 // lockObject must be held. 511 // Complicated dance due to lock ordering: 512 // Must first release the classloader object lock to 513 // allow initial definer to complete the class definition 514 // and to avoid deadlock 515 // Reclaim classloader lock object with same original recursion count 516 // Must release SystemDictionary_lock after notify, since 517 // class loader lock must be claimed before SystemDictionary_lock 518 // to prevent deadlocks 519 // 520 // The notify allows applications that did an untimed wait() on 521 // the classloader object lock to not hang. 522 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 523 assert_lock_strong(SystemDictionary_lock); 524 525 bool calledholdinglock 526 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 527 assert(calledholdinglock,"must hold lock for notify"); 528 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 529 ObjectSynchronizer::notifyall(lockObject, THREAD); 530 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 531 SystemDictionary_lock->wait(); 532 SystemDictionary_lock->unlock(); 533 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 534 SystemDictionary_lock->lock(); 535 } 536 537 // If the class in is in the placeholder table, class loading is in progress 538 // For cases where the application changes threads to load classes, it 539 // is critical to ClassCircularity detection that we try loading 540 // the superclass on the same thread internally, so we do parallel 541 // super class loading here. 542 // This also is critical in cases where the original thread gets stalled 543 // even in non-circularity situations. 544 // Note: must call resolve_super_or_fail even if null super - 545 // to force placeholder entry creation for this class for circularity detection 546 // Caller must check for pending exception 547 // Returns non-null Klass* if other thread has completed load 548 // and we are done, 549 // If return null Klass* and no pending exception, the caller must load the class 550 InstanceKlass* SystemDictionary::handle_parallel_super_load( 551 Symbol* name, Symbol* superclassname, Handle class_loader, 552 Handle protection_domain, Handle lockObject, TRAPS) { 553 554 ClassLoaderData* loader_data = class_loader_data(class_loader); 555 Dictionary* dictionary = loader_data->dictionary(); 556 unsigned int d_hash = dictionary->compute_hash(name); 557 unsigned int p_hash = placeholders()->compute_hash(name); 558 int p_index = placeholders()->hash_to_index(p_hash); 559 560 // superk is not used, resolve_super called for circularity check only 561 // This code is reached in two situations. One if this thread 562 // is loading the same class twice (e.g. ClassCircularity, or 563 // java.lang.instrument). 564 // The second is if another thread started the resolve_super first 565 // and has not yet finished. 566 // In both cases the original caller will clean up the placeholder 567 // entry on error. 568 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 569 superclassname, 570 class_loader, 571 protection_domain, 572 true, 573 CHECK_NULL); 574 575 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 576 // Serial class loaders and bootstrap classloader do wait for superclass loads 577 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 578 MutexLocker mu(SystemDictionary_lock, THREAD); 579 // Check if classloading completed while we were loading superclass or waiting 580 return find_class(d_hash, name, dictionary); 581 } 582 583 // must loop to both handle other placeholder updates 584 // and spurious notifications 585 bool super_load_in_progress = true; 586 PlaceholderEntry* placeholder; 587 while (super_load_in_progress) { 588 MutexLocker mu(SystemDictionary_lock, THREAD); 589 // Check if classloading completed while we were loading superclass or waiting 590 InstanceKlass* check = find_class(d_hash, name, dictionary); 591 if (check != NULL) { 592 // Klass is already loaded, so just return it 593 return check; 594 } else { 595 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 596 if (placeholder && placeholder->super_load_in_progress() ){ 597 // We only get here if the application has released the 598 // classloader lock when another thread was in the middle of loading a 599 // superclass/superinterface for this class, and now 600 // this thread is also trying to load this class. 601 // To minimize surprises, the first thread that started to 602 // load a class should be the one to complete the loading 603 // with the classfile it initially expected. 604 // This logic has the current thread wait once it has done 605 // all the superclass/superinterface loading it can, until 606 // the original thread completes the class loading or fails 607 // If it completes we will use the resulting InstanceKlass 608 // which we will find below in the systemDictionary. 609 // We also get here for parallel bootstrap classloader 610 if (class_loader.is_null()) { 611 SystemDictionary_lock->wait(); 612 } else { 613 double_lock_wait(lockObject, THREAD); 614 } 615 } else { 616 // If not in SD and not in PH, other thread's load must have failed 617 super_load_in_progress = false; 618 } 619 } 620 } 621 return NULL; 622 } 623 624 static void post_class_load_event(EventClassLoad* event, 625 const InstanceKlass* k, 626 const ClassLoaderData* init_cld) { 627 #if INCLUDE_TRACE 628 assert(event != NULL, "invariant"); 629 assert(k != NULL, "invariant"); 630 if (event->should_commit()) { 631 event->set_loadedClass(k); 632 event->set_definingClassLoader(k->class_loader_data()); 633 event->set_initiatingClassLoader(init_cld); 634 event->commit(); 635 } 636 #endif // INCLUDE_TRACE 637 } 638 639 static void class_define_event(InstanceKlass* k, 640 const ClassLoaderData* def_cld) { 641 #if INCLUDE_TRACE 642 EventClassDefine event; 643 if (event.should_commit()) { 644 event.set_definedClass(k); 645 event.set_definingClassLoader(def_cld); 646 event.commit(); 647 } 648 #endif // INCLUDE_TRACE 649 } 650 651 // Be careful when modifying this code: once you have run 652 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 653 // you need to find_and_remove it before returning. 654 // So be careful to not exit with a CHECK_ macro betweeen these calls. 655 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 656 Handle class_loader, 657 Handle protection_domain, 658 TRAPS) { 659 assert(name != NULL && !FieldType::is_array(name) && 660 !FieldType::is_obj(name), "invalid class name"); 661 662 EventClassLoad class_load_start_event; 663 664 HandleMark hm(THREAD); 665 666 // Fix for 4474172; see evaluation for more details 667 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 668 ClassLoaderData* loader_data = register_loader(class_loader); 669 Dictionary* dictionary = loader_data->dictionary(); 670 unsigned int d_hash = dictionary->compute_hash(name); 671 672 // Do lookup to see if class already exist and the protection domain 673 // has the right access 674 // This call uses find which checks protection domain already matches 675 // All subsequent calls use find_class, and set has_loaded_class so that 676 // before we return a result we call out to java to check for valid protection domain 677 // to allow returning the Klass* and add it to the pd_set if it is valid 678 { 679 Klass* probe = dictionary->find(d_hash, name, protection_domain); 680 if (probe != NULL) return probe; 681 } 682 683 // Non-bootstrap class loaders will call out to class loader and 684 // define via jvm/jni_DefineClass which will acquire the 685 // class loader object lock to protect against multiple threads 686 // defining the class in parallel by accident. 687 // This lock must be acquired here so the waiter will find 688 // any successful result in the SystemDictionary and not attempt 689 // the define. 690 // ParallelCapable Classloaders and the bootstrap classloader 691 // do not acquire lock here. 692 bool DoObjectLock = true; 693 if (is_parallelCapable(class_loader)) { 694 DoObjectLock = false; 695 } 696 697 unsigned int p_hash = placeholders()->compute_hash(name); 698 int p_index = placeholders()->hash_to_index(p_hash); 699 700 // Class is not in SystemDictionary so we have to do loading. 701 // Make sure we are synchronized on the class loader before we proceed 702 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 703 check_loader_lock_contention(lockObject, THREAD); 704 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 705 706 // Check again (after locking) if class already exist in SystemDictionary 707 bool class_has_been_loaded = false; 708 bool super_load_in_progress = false; 709 bool havesupername = false; 710 InstanceKlass* k = NULL; 711 PlaceholderEntry* placeholder; 712 Symbol* superclassname = NULL; 713 714 { 715 MutexLocker mu(SystemDictionary_lock, THREAD); 716 InstanceKlass* check = find_class(d_hash, name, dictionary); 717 if (check != NULL) { 718 // Klass is already loaded, so just return it 719 class_has_been_loaded = true; 720 k = check; 721 } else { 722 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 723 if (placeholder && placeholder->super_load_in_progress()) { 724 super_load_in_progress = true; 725 if (placeholder->havesupername() == true) { 726 superclassname = placeholder->supername(); 727 havesupername = true; 728 } 729 } 730 } 731 } 732 733 // If the class is in the placeholder table, class loading is in progress 734 if (super_load_in_progress && havesupername==true) { 735 k = handle_parallel_super_load(name, 736 superclassname, 737 class_loader, 738 protection_domain, 739 lockObject, THREAD); 740 if (HAS_PENDING_EXCEPTION) { 741 return NULL; 742 } 743 if (k != NULL) { 744 class_has_been_loaded = true; 745 } 746 } 747 748 bool throw_circularity_error = false; 749 if (!class_has_been_loaded) { 750 bool load_instance_added = false; 751 752 // add placeholder entry to record loading instance class 753 // Five cases: 754 // All cases need to prevent modifying bootclasssearchpath 755 // in parallel with a classload of same classname 756 // Redefineclasses uses existence of the placeholder for the duration 757 // of the class load to prevent concurrent redefinition of not completely 758 // defined classes. 759 // case 1. traditional classloaders that rely on the classloader object lock 760 // - no other need for LOAD_INSTANCE 761 // case 2. traditional classloaders that break the classloader object lock 762 // as a deadlock workaround. Detection of this case requires that 763 // this check is done while holding the classloader object lock, 764 // and that lock is still held when calling classloader's loadClass. 765 // For these classloaders, we ensure that the first requestor 766 // completes the load and other requestors wait for completion. 767 // case 3. Bootstrap classloader - don't own objectLocker 768 // This classloader supports parallelism at the classloader level, 769 // but only allows a single load of a class/classloader pair. 770 // No performance benefit and no deadlock issues. 771 // case 4. parallelCapable user level classloaders - without objectLocker 772 // Allow parallel classloading of a class/classloader pair 773 774 { 775 MutexLocker mu(SystemDictionary_lock, THREAD); 776 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 777 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 778 if (oldprobe) { 779 // only need check_seen_thread once, not on each loop 780 // 6341374 java/lang/Instrument with -Xcomp 781 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 782 throw_circularity_error = true; 783 } else { 784 // case 1: traditional: should never see load_in_progress. 785 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 786 787 // case 3: bootstrap classloader: prevent futile classloading, 788 // wait on first requestor 789 if (class_loader.is_null()) { 790 SystemDictionary_lock->wait(); 791 } else { 792 // case 2: traditional with broken classloader lock. wait on first 793 // requestor. 794 double_lock_wait(lockObject, THREAD); 795 } 796 // Check if classloading completed while we were waiting 797 InstanceKlass* check = find_class(d_hash, name, dictionary); 798 if (check != NULL) { 799 // Klass is already loaded, so just return it 800 k = check; 801 class_has_been_loaded = true; 802 } 803 // check if other thread failed to load and cleaned up 804 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 805 } 806 } 807 } 808 } 809 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 810 // case 4: parallelCapable: allow competing threads to try 811 // LOAD_INSTANCE in parallel 812 813 if (!throw_circularity_error && !class_has_been_loaded) { 814 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 815 load_instance_added = true; 816 // For class loaders that do not acquire the classloader object lock, 817 // if they did not catch another thread holding LOAD_INSTANCE, 818 // need a check analogous to the acquire ObjectLocker/find_class 819 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 820 // one final check if the load has already completed 821 // class loaders holding the ObjectLock shouldn't find the class here 822 InstanceKlass* check = find_class(d_hash, name, dictionary); 823 if (check != NULL) { 824 // Klass is already loaded, so return it after checking/adding protection domain 825 k = check; 826 class_has_been_loaded = true; 827 } 828 } 829 } 830 831 // must throw error outside of owning lock 832 if (throw_circularity_error) { 833 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 834 ResourceMark rm(THREAD); 835 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 836 } 837 838 if (!class_has_been_loaded) { 839 840 // Do actual loading 841 k = load_instance_class(name, class_loader, THREAD); 842 843 // If everything was OK (no exceptions, no null return value), and 844 // class_loader is NOT the defining loader, do a little more bookkeeping. 845 if (!HAS_PENDING_EXCEPTION && k != NULL && 846 !oopDesc::equals(k->class_loader(), class_loader())) { 847 848 check_constraints(d_hash, k, class_loader, false, THREAD); 849 850 // Need to check for a PENDING_EXCEPTION again; check_constraints 851 // can throw and doesn't use the CHECK macro. 852 if (!HAS_PENDING_EXCEPTION) { 853 { // Grabbing the Compile_lock prevents systemDictionary updates 854 // during compilations. 855 MutexLocker mu(Compile_lock, THREAD); 856 update_dictionary(d_hash, p_index, p_hash, 857 k, class_loader, THREAD); 858 } 859 860 if (JvmtiExport::should_post_class_load()) { 861 Thread *thread = THREAD; 862 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 863 JvmtiExport::post_class_load((JavaThread *) thread, k); 864 } 865 } 866 } 867 } // load_instance_class 868 869 if (load_instance_added == true) { 870 // clean up placeholder entries for LOAD_INSTANCE success or error 871 // This brackets the SystemDictionary updates for both defining 872 // and initiating loaders 873 MutexLocker mu(SystemDictionary_lock, THREAD); 874 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 875 SystemDictionary_lock->notify_all(); 876 } 877 } 878 879 if (HAS_PENDING_EXCEPTION || k == NULL) { 880 return NULL; 881 } 882 883 post_class_load_event(&class_load_start_event, k, loader_data); 884 885 #ifdef ASSERT 886 { 887 ClassLoaderData* loader_data = k->class_loader_data(); 888 MutexLocker mu(SystemDictionary_lock, THREAD); 889 Klass* kk = find_class(name, loader_data); 890 assert(kk == k, "should be present in dictionary"); 891 } 892 #endif 893 894 // return if the protection domain in NULL 895 if (protection_domain() == NULL) return k; 896 897 // Check the protection domain has the right access 898 if (dictionary->is_valid_protection_domain(d_hash, name, 899 protection_domain)) { 900 return k; 901 } 902 903 // Verify protection domain. If it fails an exception is thrown 904 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 905 906 return k; 907 } 908 909 910 // This routine does not lock the system dictionary. 911 // 912 // Since readers don't hold a lock, we must make sure that system 913 // dictionary entries are only removed at a safepoint (when only one 914 // thread is running), and are added to in a safe way (all links must 915 // be updated in an MT-safe manner). 916 // 917 // Callers should be aware that an entry could be added just after 918 // _dictionary->bucket(index) is read here, so the caller will not see 919 // the new entry. 920 921 Klass* SystemDictionary::find(Symbol* class_name, 922 Handle class_loader, 923 Handle protection_domain, 924 TRAPS) { 925 926 // The result of this call should be consistent with the result 927 // of the call to resolve_instance_class_or_null(). 928 // See evaluation 6790209 and 4474172 for more details. 929 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 930 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 931 932 if (loader_data == NULL) { 933 // If the ClassLoaderData has not been setup, 934 // then the class loader has no entries in the dictionary. 935 return NULL; 936 } 937 938 Dictionary* dictionary = loader_data->dictionary(); 939 unsigned int d_hash = dictionary->compute_hash(class_name); 940 return dictionary->find(d_hash, class_name, 941 protection_domain); 942 } 943 944 945 // Look for a loaded instance or array klass by name. Do not do any loading. 946 // return NULL in case of error. 947 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 948 Handle class_loader, 949 Handle protection_domain, 950 TRAPS) { 951 Klass* k = NULL; 952 assert(class_name != NULL, "class name must be non NULL"); 953 954 if (FieldType::is_array(class_name)) { 955 // The name refers to an array. Parse the name. 956 // dimension and object_key in FieldArrayInfo are assigned as a 957 // side-effect of this call 958 FieldArrayInfo fd; 959 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 960 if (t != T_OBJECT) { 961 k = Universe::typeArrayKlassObj(t); 962 } else { 963 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 964 } 965 if (k != NULL) { 966 k = k->array_klass_or_null(fd.dimension()); 967 } 968 } else { 969 k = find(class_name, class_loader, protection_domain, THREAD); 970 } 971 return k; 972 } 973 974 // Note: this method is much like resolve_from_stream, but 975 // does not publish the classes via the SystemDictionary. 976 // Handles unsafe_DefineAnonymousClass and redefineclasses 977 // RedefinedClasses do not add to the class hierarchy 978 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 979 Handle class_loader, 980 Handle protection_domain, 981 ClassFileStream* st, 982 const InstanceKlass* host_klass, 983 GrowableArray<Handle>* cp_patches, 984 TRAPS) { 985 986 EventClassLoad class_load_start_event; 987 988 ClassLoaderData* loader_data; 989 if (host_klass != NULL) { 990 // Create a new CLD for anonymous class, that uses the same class loader 991 // as the host_klass 992 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same"); 993 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader); 994 } else { 995 loader_data = ClassLoaderData::class_loader_data(class_loader()); 996 } 997 998 assert(st != NULL, "invariant"); 999 assert(st->need_verify(), "invariant"); 1000 1001 // Parse stream and create a klass. 1002 // Note that we do this even though this klass might 1003 // already be present in the SystemDictionary, otherwise we would not 1004 // throw potential ClassFormatErrors. 1005 1006 InstanceKlass* k = KlassFactory::create_from_stream(st, 1007 class_name, 1008 loader_data, 1009 protection_domain, 1010 host_klass, 1011 cp_patches, 1012 CHECK_NULL); 1013 1014 if (host_klass != NULL && k != NULL) { 1015 // Anonymous classes must update ClassLoaderData holder (was host_klass loader) 1016 // so that they can be unloaded when the mirror is no longer referenced. 1017 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror())); 1018 1019 { 1020 MutexLocker mu_r(Compile_lock, THREAD); 1021 1022 // Add to class hierarchy, initialize vtables, and do possible 1023 // deoptimizations. 1024 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1025 1026 // But, do not add to dictionary. 1027 1028 // compiled code dependencies need to be validated anyway 1029 notice_modification(); 1030 } 1031 1032 // Rewrite and patch constant pool here. 1033 k->link_class(CHECK_NULL); 1034 if (cp_patches != NULL) { 1035 k->constants()->patch_resolved_references(cp_patches); 1036 } 1037 1038 // If it's anonymous, initialize it now, since nobody else will. 1039 k->eager_initialize(CHECK_NULL); 1040 1041 // notify jvmti 1042 if (JvmtiExport::should_post_class_load()) { 1043 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1044 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1045 } 1046 1047 post_class_load_event(&class_load_start_event, k, loader_data); 1048 } 1049 assert(host_klass != NULL || NULL == cp_patches, 1050 "cp_patches only found with host_klass"); 1051 1052 return k; 1053 } 1054 1055 // Add a klass to the system from a stream (called by jni_DefineClass and 1056 // JVM_DefineClass). 1057 // Note: class_name can be NULL. In that case we do not know the name of 1058 // the class until we have parsed the stream. 1059 1060 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1061 Handle class_loader, 1062 Handle protection_domain, 1063 ClassFileStream* st, 1064 TRAPS) { 1065 1066 HandleMark hm(THREAD); 1067 1068 // Classloaders that support parallelism, e.g. bootstrap classloader, 1069 // do not acquire lock here 1070 bool DoObjectLock = true; 1071 if (is_parallelCapable(class_loader)) { 1072 DoObjectLock = false; 1073 } 1074 1075 ClassLoaderData* loader_data = register_loader(class_loader); 1076 1077 // Make sure we are synchronized on the class loader before we proceed 1078 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1079 check_loader_lock_contention(lockObject, THREAD); 1080 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1081 1082 assert(st != NULL, "invariant"); 1083 1084 // Parse the stream and create a klass. 1085 // Note that we do this even though this klass might 1086 // already be present in the SystemDictionary, otherwise we would not 1087 // throw potential ClassFormatErrors. 1088 InstanceKlass* k = NULL; 1089 1090 #if INCLUDE_CDS 1091 if (!DumpSharedSpaces) { 1092 k = SystemDictionaryShared::lookup_from_stream(class_name, 1093 class_loader, 1094 protection_domain, 1095 st, 1096 CHECK_NULL); 1097 } 1098 #endif 1099 1100 if (k == NULL) { 1101 if (st->buffer() == NULL) { 1102 return NULL; 1103 } 1104 k = KlassFactory::create_from_stream(st, 1105 class_name, 1106 loader_data, 1107 protection_domain, 1108 NULL, // host_klass 1109 NULL, // cp_patches 1110 CHECK_NULL); 1111 } 1112 1113 assert(k != NULL, "no klass created"); 1114 Symbol* h_name = k->name(); 1115 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1116 1117 // Add class just loaded 1118 // If a class loader supports parallel classloading handle parallel define requests 1119 // find_or_define_instance_class may return a different InstanceKlass 1120 if (is_parallelCapable(class_loader)) { 1121 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1122 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1123 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1124 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1125 loader_data->add_to_deallocate_list(k); 1126 k = defined_k; 1127 } 1128 } else { 1129 define_instance_class(k, THREAD); 1130 } 1131 1132 // If defining the class throws an exception register 'k' for cleanup. 1133 if (HAS_PENDING_EXCEPTION) { 1134 assert(k != NULL, "Must have an instance klass here!"); 1135 loader_data->add_to_deallocate_list(k); 1136 return NULL; 1137 } 1138 1139 // Make sure we have an entry in the SystemDictionary on success 1140 debug_only( { 1141 MutexLocker mu(SystemDictionary_lock, THREAD); 1142 1143 Klass* check = find_class(h_name, k->class_loader_data()); 1144 assert(check == k, "should be present in the dictionary"); 1145 } ); 1146 1147 return k; 1148 } 1149 1150 #if INCLUDE_CDS 1151 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1152 int number_of_entries) { 1153 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1154 "bad shared dictionary size."); 1155 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1156 _shared_dictionary_size, t, number_of_entries); 1157 } 1158 1159 1160 // If there is a shared dictionary, then find the entry for the 1161 // given shared system class, if any. 1162 1163 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1164 if (shared_dictionary() != NULL) { 1165 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1166 int d_index = shared_dictionary()->hash_to_index(d_hash); 1167 1168 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1169 } else { 1170 return NULL; 1171 } 1172 } 1173 1174 1175 // Load a class from the shared spaces (found through the shared system 1176 // dictionary). Force the superclass and all interfaces to be loaded. 1177 // Update the class definition to include sibling classes and no 1178 // subclasses (yet). [Classes in the shared space are not part of the 1179 // object hierarchy until loaded.] 1180 1181 InstanceKlass* SystemDictionary::load_shared_class( 1182 Symbol* class_name, Handle class_loader, TRAPS) { 1183 InstanceKlass* ik = find_shared_class(class_name); 1184 // Make sure we only return the boot class for the NULL classloader. 1185 if (ik != NULL && 1186 ik->is_shared_boot_class() && class_loader.is_null()) { 1187 Handle protection_domain; 1188 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1189 } 1190 return NULL; 1191 } 1192 1193 // Check if a shared class can be loaded by the specific classloader: 1194 // 1195 // NULL classloader: 1196 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1197 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1198 // be defined in an unnamed module. 1199 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1200 InstanceKlass* ik, 1201 Handle class_loader, TRAPS) { 1202 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1203 "Cannot use sharing if java.base is patched"); 1204 ResourceMark rm; 1205 int path_index = ik->shared_classpath_index(); 1206 ClassLoaderData* loader_data = class_loader_data(class_loader); 1207 if (path_index < 0) { 1208 // path_index < 0 indicates that the class is intended for a custom loader 1209 // and should not be loaded by boot/platform/app loaders 1210 if (loader_data->is_builtin_class_loader_data()) { 1211 return false; 1212 } else { 1213 return true; 1214 } 1215 } 1216 SharedClassPathEntry* ent = 1217 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); 1218 if (!Universe::is_module_initialized()) { 1219 assert(ent != NULL && ent->is_modules_image(), 1220 "Loading non-bootstrap classes before the module system is initialized"); 1221 assert(class_loader.is_null(), "sanity"); 1222 return true; 1223 } 1224 // Get the pkg_entry from the classloader 1225 TempNewSymbol pkg_name = NULL; 1226 PackageEntry* pkg_entry = NULL; 1227 ModuleEntry* mod_entry = NULL; 1228 const char* pkg_string = NULL; 1229 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1230 if (pkg_name != NULL) { 1231 pkg_string = pkg_name->as_C_string(); 1232 if (loader_data != NULL) { 1233 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1234 } 1235 if (pkg_entry != NULL) { 1236 mod_entry = pkg_entry->module(); 1237 } 1238 } 1239 1240 // If the archived class is from a module that has been patched at runtime, 1241 // the class cannot be loaded from the archive. 1242 if (mod_entry != NULL && mod_entry->is_patched()) { 1243 return false; 1244 } 1245 1246 if (class_loader.is_null()) { 1247 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1248 // The NULL classloader can load archived class originated from the 1249 // "modules" jimage and the -Xbootclasspath/a. For class from the 1250 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1251 // by the NULL classloader. 1252 if (mod_entry != NULL) { 1253 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1254 // ModuleEntry's location agrees with the archived class' origination. 1255 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1256 return true; // Module class from the "module" jimage 1257 } 1258 } 1259 1260 // If the archived class is not from the "module" jimage, the class can be 1261 // loaded by the NULL classloader if 1262 // 1263 // 1. the class is from the unamed package 1264 // 2. or, the class is not from a module defined in the NULL classloader 1265 // 3. or, the class is from an unamed module 1266 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1267 // the class is from the -Xbootclasspath/a 1268 if (pkg_string == NULL || 1269 pkg_entry == NULL || 1270 pkg_entry->in_unnamed_module()) { 1271 assert(mod_entry == NULL || 1272 mod_entry == loader_data->unnamed_module(), 1273 "the unnamed module is not defined in the classloader"); 1274 return true; 1275 } 1276 } 1277 return false; 1278 } else { 1279 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1280 ik, class_loader, pkg_string, pkg_name, 1281 pkg_entry, mod_entry, CHECK_(false)); 1282 return res; 1283 } 1284 } 1285 1286 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1287 Handle class_loader, 1288 Handle protection_domain, TRAPS) { 1289 1290 if (ik != NULL) { 1291 Symbol* class_name = ik->name(); 1292 1293 bool visible = is_shared_class_visible( 1294 class_name, ik, class_loader, CHECK_NULL); 1295 if (!visible) { 1296 return NULL; 1297 } 1298 1299 // Resolve the superclass and interfaces. They must be the same 1300 // as in dump time, because the layout of <ik> depends on 1301 // the specific layout of ik->super() and ik->local_interfaces(). 1302 // 1303 // If unexpected superclass or interfaces are found, we cannot 1304 // load <ik> from the shared archive. 1305 1306 if (ik->super() != NULL) { 1307 Symbol* cn = ik->super()->name(); 1308 Klass *s = resolve_super_or_fail(class_name, cn, 1309 class_loader, protection_domain, true, CHECK_NULL); 1310 if (s != ik->super()) { 1311 // The dynamically resolved super class is not the same as the one we used during dump time, 1312 // so we cannot use ik. 1313 return NULL; 1314 } else { 1315 assert(s->is_shared(), "must be"); 1316 } 1317 } 1318 1319 Array<Klass*>* interfaces = ik->local_interfaces(); 1320 int num_interfaces = interfaces->length(); 1321 for (int index = 0; index < num_interfaces; index++) { 1322 Klass* k = interfaces->at(index); 1323 Symbol* name = k->name(); 1324 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1325 if (k != i) { 1326 // The dynamically resolved interface class is not the same as the one we used during dump time, 1327 // so we cannot use ik. 1328 return NULL; 1329 } else { 1330 assert(i->is_shared(), "must be"); 1331 } 1332 } 1333 1334 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1335 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1336 if (new_ik != NULL) { 1337 // The class is changed by CFLH. Return the new class. The shared class is 1338 // not used. 1339 return new_ik; 1340 } 1341 1342 // Adjust methods to recover missing data. They need addresses for 1343 // interpreter entry points and their default native method address 1344 // must be reset. 1345 1346 // Updating methods must be done under a lock so multiple 1347 // threads don't update these in parallel 1348 // 1349 // Shared classes are all currently loaded by either the bootstrap or 1350 // internal parallel class loaders, so this will never cause a deadlock 1351 // on a custom class loader lock. 1352 1353 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1354 { 1355 HandleMark hm(THREAD); 1356 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1357 check_loader_lock_contention(lockObject, THREAD); 1358 ObjectLocker ol(lockObject, THREAD, true); 1359 // prohibited package check assumes all classes loaded from archive call 1360 // restore_unshareable_info which calls ik->set_package() 1361 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1362 } 1363 1364 ik->print_class_load_logging(loader_data, NULL, NULL); 1365 1366 // For boot loader, ensure that GetSystemPackage knows that a class in this 1367 // package was loaded. 1368 if (class_loader.is_null()) { 1369 int path_index = ik->shared_classpath_index(); 1370 ResourceMark rm; 1371 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1372 } 1373 1374 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1375 // Only dump the classes that can be stored into CDS archive 1376 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1377 ResourceMark rm(THREAD); 1378 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1379 classlist_file->flush(); 1380 } 1381 } 1382 1383 // notify a class loaded from shared object 1384 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1385 } 1386 1387 ik->set_has_passed_fingerprint_check(false); 1388 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1389 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1390 uint64_t cds_fp = ik->get_stored_fingerprint(); 1391 if (aot_fp != 0 && aot_fp == cds_fp) { 1392 // This class matches with a class saved in an AOT library 1393 ik->set_has_passed_fingerprint_check(true); 1394 } else { 1395 ResourceMark rm; 1396 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1397 } 1398 } 1399 return ik; 1400 } 1401 1402 void SystemDictionary::clear_invoke_method_table() { 1403 SymbolPropertyEntry* spe = NULL; 1404 for (int index = 0; index < _invoke_method_table->table_size(); index++) { 1405 SymbolPropertyEntry* p = _invoke_method_table->bucket(index); 1406 while (p != NULL) { 1407 spe = p; 1408 p = p->next(); 1409 _invoke_method_table->free_entry(spe); 1410 } 1411 } 1412 } 1413 #endif // INCLUDE_CDS 1414 1415 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1416 1417 if (class_loader.is_null()) { 1418 ResourceMark rm; 1419 PackageEntry* pkg_entry = NULL; 1420 bool search_only_bootloader_append = false; 1421 ClassLoaderData *loader_data = class_loader_data(class_loader); 1422 1423 // Find the package in the boot loader's package entry table. 1424 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1425 if (pkg_name != NULL) { 1426 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1427 } 1428 1429 // Prior to attempting to load the class, enforce the boot loader's 1430 // visibility boundaries. 1431 if (!Universe::is_module_initialized()) { 1432 // During bootstrapping, prior to module initialization, any 1433 // class attempting to be loaded must be checked against the 1434 // java.base packages in the boot loader's PackageEntryTable. 1435 // No class outside of java.base is allowed to be loaded during 1436 // this bootstrapping window. 1437 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1438 // Class is either in the unnamed package or in 1439 // a named package within the unnamed module. Either 1440 // case is outside of java.base, do not attempt to 1441 // load the class post java.base definition. If 1442 // java.base has not been defined, let the class load 1443 // and its package will be checked later by 1444 // ModuleEntryTable::verify_javabase_packages. 1445 if (ModuleEntryTable::javabase_defined()) { 1446 return NULL; 1447 } 1448 } else { 1449 // Check that the class' package is defined within java.base. 1450 ModuleEntry* mod_entry = pkg_entry->module(); 1451 Symbol* mod_entry_name = mod_entry->name(); 1452 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1453 return NULL; 1454 } 1455 } 1456 } else { 1457 // After the module system has been initialized, check if the class' 1458 // package is in a module defined to the boot loader. 1459 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1460 // Class is either in the unnamed package, in a named package 1461 // within a module not defined to the boot loader or in a 1462 // a named package within the unnamed module. In all cases, 1463 // limit visibility to search for the class only in the boot 1464 // loader's append path. 1465 search_only_bootloader_append = true; 1466 } 1467 } 1468 1469 // Prior to bootstrapping's module initialization, never load a class outside 1470 // of the boot loader's module path 1471 assert(Universe::is_module_initialized() || 1472 !search_only_bootloader_append, 1473 "Attempt to load a class outside of boot loader's module path"); 1474 1475 // Search the shared system dictionary for classes preloaded into the 1476 // shared spaces. 1477 InstanceKlass* k = NULL; 1478 { 1479 #if INCLUDE_CDS 1480 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1481 k = load_shared_class(class_name, class_loader, THREAD); 1482 #endif 1483 } 1484 1485 if (k == NULL) { 1486 // Use VM class loader 1487 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1488 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1489 } 1490 1491 // find_or_define_instance_class may return a different InstanceKlass 1492 if (k != NULL) { 1493 InstanceKlass* defined_k = 1494 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1495 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1496 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1497 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1498 loader_data->add_to_deallocate_list(k); 1499 k = defined_k; 1500 } else if (HAS_PENDING_EXCEPTION) { 1501 loader_data->add_to_deallocate_list(k); 1502 return NULL; 1503 } 1504 } 1505 return k; 1506 } else { 1507 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1508 ResourceMark rm(THREAD); 1509 1510 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1511 JavaThread* jt = (JavaThread*) THREAD; 1512 1513 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1514 ClassLoader::perf_app_classload_selftime(), 1515 ClassLoader::perf_app_classload_count(), 1516 jt->get_thread_stat()->perf_recursion_counts_addr(), 1517 jt->get_thread_stat()->perf_timers_addr(), 1518 PerfClassTraceTime::CLASS_LOAD); 1519 1520 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1521 // Translate to external class name format, i.e., convert '/' chars to '.' 1522 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1523 1524 JavaValue result(T_OBJECT); 1525 1526 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1527 1528 // Call public unsynchronized loadClass(String) directly for all class loaders. 1529 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1530 // acquire a class-name based lock rather than the class loader object lock. 1531 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1532 JavaCalls::call_virtual(&result, 1533 class_loader, 1534 spec_klass, 1535 vmSymbols::loadClass_name(), 1536 vmSymbols::string_class_signature(), 1537 string, 1538 CHECK_NULL); 1539 1540 assert(result.get_type() == T_OBJECT, "just checking"); 1541 oop obj = (oop) result.get_jobject(); 1542 1543 // Primitive classes return null since forName() can not be 1544 // used to obtain any of the Class objects representing primitives or void 1545 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1546 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1547 // For user defined Java class loaders, check that the name returned is 1548 // the same as that requested. This check is done for the bootstrap 1549 // loader when parsing the class file. 1550 if (class_name == k->name()) { 1551 return k; 1552 } 1553 } 1554 // Class is not found or has the wrong name, return NULL 1555 return NULL; 1556 } 1557 } 1558 1559 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1560 1561 HandleMark hm(THREAD); 1562 ClassLoaderData* loader_data = k->class_loader_data(); 1563 Handle class_loader_h(THREAD, loader_data->class_loader()); 1564 1565 // for bootstrap and other parallel classloaders don't acquire lock, 1566 // use placeholder token 1567 // If a parallelCapable class loader calls define_instance_class instead of 1568 // find_or_define_instance_class to get here, we have a timing 1569 // hole with systemDictionary updates and check_constraints 1570 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1571 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1572 compute_loader_lock_object(class_loader_h, THREAD)), 1573 "define called without lock"); 1574 } 1575 1576 // Check class-loading constraints. Throw exception if violation is detected. 1577 // Grabs and releases SystemDictionary_lock 1578 // The check_constraints/find_class call and update_dictionary sequence 1579 // must be "atomic" for a specific class/classloader pair so we never 1580 // define two different instanceKlasses for that class/classloader pair. 1581 // Existing classloaders will call define_instance_class with the 1582 // classloader lock held 1583 // Parallel classloaders will call find_or_define_instance_class 1584 // which will require a token to perform the define class 1585 Symbol* name_h = k->name(); 1586 Dictionary* dictionary = loader_data->dictionary(); 1587 unsigned int d_hash = dictionary->compute_hash(name_h); 1588 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1589 1590 // Register class just loaded with class loader (placed in Vector) 1591 // Note we do this before updating the dictionary, as this can 1592 // fail with an OutOfMemoryError (if it does, we will *not* put this 1593 // class in the dictionary and will not update the class hierarchy). 1594 // JVMTI FollowReferences needs to find the classes this way. 1595 if (k->class_loader() != NULL) { 1596 methodHandle m(THREAD, Universe::loader_addClass_method()); 1597 JavaValue result(T_VOID); 1598 JavaCallArguments args(class_loader_h); 1599 args.push_oop(Handle(THREAD, k->java_mirror())); 1600 JavaCalls::call(&result, m, &args, CHECK); 1601 } 1602 1603 // Add the new class. We need recompile lock during update of CHA. 1604 { 1605 unsigned int p_hash = placeholders()->compute_hash(name_h); 1606 int p_index = placeholders()->hash_to_index(p_hash); 1607 1608 MutexLocker mu_r(Compile_lock, THREAD); 1609 1610 // Add to class hierarchy, initialize vtables, and do possible 1611 // deoptimizations. 1612 add_to_hierarchy(k, CHECK); // No exception, but can block 1613 1614 // Add to systemDictionary - so other classes can see it. 1615 // Grabs and releases SystemDictionary_lock 1616 update_dictionary(d_hash, p_index, p_hash, 1617 k, class_loader_h, THREAD); 1618 } 1619 k->eager_initialize(THREAD); 1620 1621 // notify jvmti 1622 if (JvmtiExport::should_post_class_load()) { 1623 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1624 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1625 1626 } 1627 class_define_event(k, loader_data); 1628 } 1629 1630 // Support parallel classloading 1631 // All parallel class loaders, including bootstrap classloader 1632 // lock a placeholder entry for this class/class_loader pair 1633 // to allow parallel defines of different classes for this class loader 1634 // With AllowParallelDefine flag==true, in case they do not synchronize around 1635 // FindLoadedClass/DefineClass, calls, we check for parallel 1636 // loading for them, wait if a defineClass is in progress 1637 // and return the initial requestor's results 1638 // This flag does not apply to the bootstrap classloader. 1639 // With AllowParallelDefine flag==false, call through to define_instance_class 1640 // which will throw LinkageError: duplicate class definition. 1641 // False is the requested default. 1642 // For better performance, the class loaders should synchronize 1643 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1644 // potentially waste time reading and parsing the bytestream. 1645 // Note: VM callers should ensure consistency of k/class_name,class_loader 1646 // Be careful when modifying this code: once you have run 1647 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1648 // you need to find_and_remove it before returning. 1649 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1650 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1651 InstanceKlass* k, TRAPS) { 1652 1653 Symbol* name_h = k->name(); // passed in class_name may be null 1654 ClassLoaderData* loader_data = class_loader_data(class_loader); 1655 Dictionary* dictionary = loader_data->dictionary(); 1656 1657 unsigned int d_hash = dictionary->compute_hash(name_h); 1658 1659 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1660 unsigned int p_hash = placeholders()->compute_hash(name_h); 1661 int p_index = placeholders()->hash_to_index(p_hash); 1662 PlaceholderEntry* probe; 1663 1664 { 1665 MutexLocker mu(SystemDictionary_lock, THREAD); 1666 // First check if class already defined 1667 if (is_parallelDefine(class_loader)) { 1668 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1669 if (check != NULL) { 1670 return check; 1671 } 1672 } 1673 1674 // Acquire define token for this class/classloader 1675 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1676 // Wait if another thread defining in parallel 1677 // All threads wait - even those that will throw duplicate class: otherwise 1678 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1679 // if other thread has not finished updating dictionary 1680 while (probe->definer() != NULL) { 1681 SystemDictionary_lock->wait(); 1682 } 1683 // Only special cases allow parallel defines and can use other thread's results 1684 // Other cases fall through, and may run into duplicate defines 1685 // caught by finding an entry in the SystemDictionary 1686 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1687 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1688 SystemDictionary_lock->notify_all(); 1689 #ifdef ASSERT 1690 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1691 assert(check != NULL, "definer missed recording success"); 1692 #endif 1693 return probe->instance_klass(); 1694 } else { 1695 // This thread will define the class (even if earlier thread tried and had an error) 1696 probe->set_definer(THREAD); 1697 } 1698 } 1699 1700 define_instance_class(k, THREAD); 1701 1702 Handle linkage_exception = Handle(); // null handle 1703 1704 // definer must notify any waiting threads 1705 { 1706 MutexLocker mu(SystemDictionary_lock, THREAD); 1707 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1708 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1709 if (probe != NULL) { 1710 if (HAS_PENDING_EXCEPTION) { 1711 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1712 CLEAR_PENDING_EXCEPTION; 1713 } else { 1714 probe->set_instance_klass(k); 1715 } 1716 probe->set_definer(NULL); 1717 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1718 SystemDictionary_lock->notify_all(); 1719 } 1720 } 1721 1722 // Can't throw exception while holding lock due to rank ordering 1723 if (linkage_exception() != NULL) { 1724 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1725 } 1726 1727 return k; 1728 } 1729 1730 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1731 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1732 if (class_loader.is_null()) { 1733 return Handle(THREAD, _system_loader_lock_obj); 1734 } else { 1735 return class_loader; 1736 } 1737 } 1738 1739 // This method is added to check how often we have to wait to grab loader 1740 // lock. The results are being recorded in the performance counters defined in 1741 // ClassLoader::_sync_systemLoaderLockContentionRate and 1742 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1743 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1744 if (!UsePerfData) { 1745 return; 1746 } 1747 1748 assert(!loader_lock.is_null(), "NULL lock object"); 1749 1750 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1751 == ObjectSynchronizer::owner_other) { 1752 // contention will likely happen, so increment the corresponding 1753 // contention counter. 1754 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) { 1755 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1756 } else { 1757 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1758 } 1759 } 1760 } 1761 1762 // ---------------------------------------------------------------------------- 1763 // Lookup 1764 1765 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1766 Symbol* class_name, 1767 Dictionary* dictionary) { 1768 assert_locked_or_safepoint(SystemDictionary_lock); 1769 int index = dictionary->hash_to_index(hash); 1770 return dictionary->find_class(index, hash, class_name); 1771 } 1772 1773 1774 // Basic find on classes in the midst of being loaded 1775 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1776 ClassLoaderData* loader_data) { 1777 assert_locked_or_safepoint(SystemDictionary_lock); 1778 unsigned int p_hash = placeholders()->compute_hash(class_name); 1779 int p_index = placeholders()->hash_to_index(p_hash); 1780 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1781 } 1782 1783 1784 // Used for assertions and verification only 1785 // Precalculating the hash and index is an optimization because there are many lookups 1786 // before adding the class. 1787 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1788 assert_locked_or_safepoint(SystemDictionary_lock); 1789 #ifndef ASSERT 1790 guarantee(VerifyBeforeGC || 1791 VerifyDuringGC || 1792 VerifyBeforeExit || 1793 VerifyDuringStartup || 1794 VerifyAfterGC, "too expensive"); 1795 #endif 1796 1797 Dictionary* dictionary = loader_data->dictionary(); 1798 unsigned int d_hash = dictionary->compute_hash(class_name); 1799 return find_class(d_hash, class_name, dictionary); 1800 } 1801 1802 1803 // ---------------------------------------------------------------------------- 1804 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1805 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1806 // before a new class is used. 1807 1808 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1809 assert(k != NULL, "just checking"); 1810 assert_locked_or_safepoint(Compile_lock); 1811 1812 // Link into hierachy. Make sure the vtables are initialized before linking into 1813 k->append_to_sibling_list(); // add to superklass/sibling list 1814 k->process_interfaces(THREAD); // handle all "implements" declarations 1815 k->set_init_state(InstanceKlass::loaded); 1816 // Now flush all code that depended on old class hierarchy. 1817 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1818 // Also, first reinitialize vtable because it may have gotten out of synch 1819 // while the new class wasn't connected to the class hierarchy. 1820 CodeCache::flush_dependents_on(k); 1821 } 1822 1823 // ---------------------------------------------------------------------------- 1824 // GC support 1825 1826 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1827 roots_oops_do(blk, NULL); 1828 } 1829 1830 1831 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1832 // Note: anonymous classes are not in the SD. 1833 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, 1834 GCTimer* gc_timer, 1835 bool do_cleaning) { 1836 1837 { 1838 GCTraceTime(Debug, gc, phases) t("SystemDictionary WeakHandle cleaning", gc_timer); 1839 vm_weak_oop_storage()->weak_oops_do(is_alive, &do_nothing_cl); 1840 } 1841 1842 bool unloading_occurred; 1843 { 1844 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1845 1846 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1847 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning); 1848 } 1849 1850 if (unloading_occurred) { 1851 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1852 constraints()->purge_loader_constraints(); 1853 resolution_errors()->purge_resolution_errors(); 1854 } 1855 1856 { 1857 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1858 // Oops referenced by the protection domain cache table may get unreachable independently 1859 // of the class loader (eg. cached protection domain oops). So we need to 1860 // explicitly unlink them here. 1861 _pd_cache_table->unlink(); 1862 } 1863 1864 if (do_cleaning) { 1865 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1866 ResolvedMethodTable::unlink(); 1867 } 1868 1869 return unloading_occurred; 1870 } 1871 1872 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1873 strong->do_oop(&_java_system_loader); 1874 strong->do_oop(&_java_platform_loader); 1875 strong->do_oop(&_system_loader_lock_obj); 1876 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) 1877 1878 // Do strong roots marking if the closures are the same. 1879 if (strong == weak || !ClassUnloading) { 1880 // Only the protection domain oops contain references into the heap. Iterate 1881 // over all of them. 1882 vm_weak_oop_storage()->oops_do(strong); 1883 } else { 1884 if (weak != NULL) { 1885 vm_weak_oop_storage()->oops_do(weak); 1886 } 1887 } 1888 1889 // Visit extra methods 1890 invoke_method_table()->oops_do(strong); 1891 } 1892 1893 void SystemDictionary::oops_do(OopClosure* f) { 1894 f->do_oop(&_java_system_loader); 1895 f->do_oop(&_java_platform_loader); 1896 f->do_oop(&_system_loader_lock_obj); 1897 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1898 1899 // Visit extra methods 1900 invoke_method_table()->oops_do(f); 1901 1902 vm_weak_oop_storage()->oops_do(f); 1903 } 1904 1905 // CDS: scan and relocate all classes in the system dictionary. 1906 void SystemDictionary::classes_do(MetaspaceClosure* it) { 1907 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); 1908 } 1909 1910 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1911 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1912 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1913 it->push(well_known_klass_addr((WKID)id)); 1914 } 1915 } 1916 1917 void SystemDictionary::methods_do(void f(Method*)) { 1918 // Walk methods in loaded classes 1919 ClassLoaderDataGraph::methods_do(f); 1920 // Walk method handle intrinsics 1921 invoke_method_table()->methods_do(f); 1922 } 1923 1924 class RemoveClassesClosure : public CLDClosure { 1925 public: 1926 void do_cld(ClassLoaderData* cld) { 1927 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 1928 cld->dictionary()->remove_classes_in_error_state(); 1929 } 1930 } 1931 }; 1932 1933 void SystemDictionary::remove_classes_in_error_state() { 1934 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 1935 RemoveClassesClosure rcc; 1936 ClassLoaderDataGraph::cld_do(&rcc); 1937 } 1938 1939 // ---------------------------------------------------------------------------- 1940 // Lazily load klasses 1941 1942 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1943 // if multiple threads calling this function, only one thread will load 1944 // the class. The other threads will find the loaded version once the 1945 // class is loaded. 1946 Klass* aos = _abstract_ownable_synchronizer_klass; 1947 if (aos == NULL) { 1948 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1949 // Force a fence to prevent any read before the write completes 1950 OrderAccess::fence(); 1951 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); 1952 } 1953 } 1954 1955 // ---------------------------------------------------------------------------- 1956 // Initialization 1957 1958 void SystemDictionary::initialize(TRAPS) { 1959 // Allocate arrays 1960 _placeholders = new PlaceholderTable(_placeholder_table_size); 1961 _number_of_modifications = 0; 1962 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1963 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1964 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1965 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 1966 1967 // Allocate private object used as system class loader lock 1968 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1969 // Initialize basic classes 1970 initialize_preloaded_classes(CHECK); 1971 1972 CDS_ONLY(SystemDictionaryShared::initialize_locks();) 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, 2127 bool defining, 2128 TRAPS) { 2129 ResourceMark rm(THREAD); 2130 stringStream ss; 2131 bool throwException = false; 2132 2133 const char *linkage_error1 = NULL; 2134 const char *linkage_error2 = NULL; 2135 const char *linkage_error3 = ""; 2136 // Remember the loader of the similar class that is already loaded. 2137 const char *existing_klass_loader_name = ""; 2138 2139 { 2140 Symbol* name = k->name(); 2141 ClassLoaderData *loader_data = class_loader_data(class_loader); 2142 2143 MutexLocker mu(SystemDictionary_lock, THREAD); 2144 2145 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2146 if (check != NULL) { 2147 // If different InstanceKlass - duplicate class definition, 2148 // else - ok, class loaded by a different thread in parallel. 2149 // We should only have found it if it was done loading and ok to use. 2150 // The dictionary only holds instance classes, placeholders 2151 // also hold array classes. 2152 2153 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2154 if ((defining == true) || (k != check)) { 2155 throwException = true; 2156 ss.print("loader %s", java_lang_ClassLoader::describe_external(class_loader())); 2157 ss.print(" attempted duplicate %s definition for %s.", 2158 k->external_kind(), k->external_name()); 2159 } else { 2160 return; 2161 } 2162 } 2163 2164 #ifdef ASSERT 2165 Symbol* ph_check = find_placeholder(name, loader_data); 2166 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2167 #endif 2168 2169 if (throwException == false) { 2170 if (constraints()->check_or_update(k, class_loader, name) == false) { 2171 throwException = true; 2172 ss.print("loader constraint violation: loader %s", 2173 java_lang_ClassLoader::describe_external(class_loader())); 2174 ss.print(" wants to load %s %s.", 2175 k->external_kind(), k->external_name()); 2176 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); 2177 if (existing_klass->class_loader() != class_loader()) { 2178 ss.print(" A different %s with the same name was previously loaded by %s.", 2179 existing_klass->external_kind(), 2180 java_lang_ClassLoader::describe_external(existing_klass->class_loader())); 2181 } 2182 } 2183 } 2184 } 2185 2186 // Throw error now if needed (cannot throw while holding 2187 // SystemDictionary_lock because of rank ordering) 2188 if (throwException == true) { 2189 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); 2190 } 2191 } 2192 2193 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2194 // have been called. 2195 void SystemDictionary::update_dictionary(unsigned int d_hash, 2196 int p_index, unsigned int p_hash, 2197 InstanceKlass* k, 2198 Handle class_loader, 2199 TRAPS) { 2200 // Compile_lock prevents systemDictionary updates during compilations 2201 assert_locked_or_safepoint(Compile_lock); 2202 Symbol* name = k->name(); 2203 ClassLoaderData *loader_data = class_loader_data(class_loader); 2204 2205 { 2206 MutexLocker mu1(SystemDictionary_lock, THREAD); 2207 2208 // See whether biased locking is enabled and if so set it for this 2209 // klass. 2210 // Note that this must be done past the last potential blocking 2211 // point / safepoint. We enable biased locking lazily using a 2212 // VM_Operation to iterate the SystemDictionary and installing the 2213 // biasable mark word into each InstanceKlass's prototype header. 2214 // To avoid race conditions where we accidentally miss enabling the 2215 // optimization for one class in the process of being added to the 2216 // dictionary, we must not safepoint after the test of 2217 // BiasedLocking::enabled(). 2218 if (UseBiasedLocking && BiasedLocking::enabled()) { 2219 // Set biased locking bit for all loaded classes; it will be 2220 // cleared if revocation occurs too often for this type 2221 // NOTE that we must only do this when the class is initally 2222 // defined, not each time it is referenced from a new class loader 2223 if (oopDesc::equals(k->class_loader(), class_loader())) { 2224 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2225 } 2226 } 2227 2228 // Make a new dictionary entry. 2229 Dictionary* dictionary = loader_data->dictionary(); 2230 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2231 if (sd_check == NULL) { 2232 dictionary->add_klass(d_hash, name, k); 2233 notice_modification(); 2234 } 2235 #ifdef ASSERT 2236 sd_check = find_class(d_hash, name, dictionary); 2237 assert (sd_check != NULL, "should have entry in dictionary"); 2238 // Note: there may be a placeholder entry: for circularity testing 2239 // or for parallel defines 2240 #endif 2241 SystemDictionary_lock->notify_all(); 2242 } 2243 } 2244 2245 2246 // Try to find a class name using the loader constraints. The 2247 // loader constraints might know about a class that isn't fully loaded 2248 // yet and these will be ignored. 2249 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2250 Symbol* class_name, Handle class_loader, TRAPS) { 2251 2252 // First see if it has been loaded directly. 2253 // Force the protection domain to be null. (This removes protection checks.) 2254 Handle no_protection_domain; 2255 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2256 no_protection_domain, CHECK_NULL); 2257 if (klass != NULL) 2258 return klass; 2259 2260 // Now look to see if it has been loaded elsewhere, and is subject to 2261 // a loader constraint that would require this loader to return the 2262 // klass that is already loaded. 2263 if (FieldType::is_array(class_name)) { 2264 // For array classes, their Klass*s are not kept in the 2265 // constraint table. The element Klass*s are. 2266 FieldArrayInfo fd; 2267 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2268 if (t != T_OBJECT) { 2269 klass = Universe::typeArrayKlassObj(t); 2270 } else { 2271 MutexLocker mu(SystemDictionary_lock, THREAD); 2272 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2273 } 2274 // If element class already loaded, allocate array klass 2275 if (klass != NULL) { 2276 klass = klass->array_klass_or_null(fd.dimension()); 2277 } 2278 } else { 2279 MutexLocker mu(SystemDictionary_lock, THREAD); 2280 // Non-array classes are easy: simply check the constraint table. 2281 klass = constraints()->find_constrained_klass(class_name, class_loader); 2282 } 2283 2284 return klass; 2285 } 2286 2287 2288 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2289 Handle class_loader1, 2290 Handle class_loader2, 2291 Thread* THREAD) { 2292 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2293 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2294 2295 Symbol* constraint_name = NULL; 2296 if (!FieldType::is_array(class_name)) { 2297 constraint_name = class_name; 2298 } else { 2299 // For array classes, their Klass*s are not kept in the 2300 // constraint table. The element classes are. 2301 FieldArrayInfo fd; 2302 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2303 // primitive types always pass 2304 if (t != T_OBJECT) { 2305 return true; 2306 } else { 2307 constraint_name = fd.object_key(); 2308 } 2309 } 2310 2311 Dictionary* dictionary1 = loader_data1->dictionary(); 2312 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2313 2314 Dictionary* dictionary2 = loader_data2->dictionary(); 2315 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2316 2317 { 2318 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2319 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2320 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2321 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2322 klass2, class_loader2); 2323 } 2324 } 2325 2326 // Add entry to resolution error table to record the error when the first 2327 // attempt to resolve a reference to a class has failed. 2328 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2329 Symbol* error, Symbol* message) { 2330 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2331 int index = resolution_errors()->hash_to_index(hash); 2332 { 2333 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2334 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2335 } 2336 } 2337 2338 // Delete a resolution error for RedefineClasses for a constant pool is going away 2339 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2340 resolution_errors()->delete_entry(pool); 2341 } 2342 2343 // Lookup resolution error table. Returns error if found, otherwise NULL. 2344 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2345 Symbol** message) { 2346 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2347 int index = resolution_errors()->hash_to_index(hash); 2348 { 2349 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2350 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2351 if (entry != NULL) { 2352 *message = entry->message(); 2353 return entry->error(); 2354 } else { 2355 return NULL; 2356 } 2357 } 2358 } 2359 2360 2361 // Signature constraints ensure that callers and callees agree about 2362 // the meaning of type names in their signatures. This routine is the 2363 // intake for constraints. It collects them from several places: 2364 // 2365 // * LinkResolver::resolve_method (if check_access is true) requires 2366 // that the resolving class (the caller) and the defining class of 2367 // the resolved method (the callee) agree on each type in the 2368 // method's signature. 2369 // 2370 // * LinkResolver::resolve_interface_method performs exactly the same 2371 // checks. 2372 // 2373 // * LinkResolver::resolve_field requires that the constant pool 2374 // attempting to link to a field agree with the field's defining 2375 // class about the type of the field signature. 2376 // 2377 // * klassVtable::initialize_vtable requires that, when a class 2378 // overrides a vtable entry allocated by a superclass, that the 2379 // overriding method (i.e., the callee) agree with the superclass 2380 // on each type in the method's signature. 2381 // 2382 // * klassItable::initialize_itable requires that, when a class fills 2383 // in its itables, for each non-abstract method installed in an 2384 // itable, the method (i.e., the callee) agree with the interface 2385 // on each type in the method's signature. 2386 // 2387 // All those methods have a boolean (check_access, checkconstraints) 2388 // which turns off the checks. This is used from specialized contexts 2389 // such as bootstrapping, dumping, and debugging. 2390 // 2391 // No direct constraint is placed between the class and its 2392 // supertypes. Constraints are only placed along linked relations 2393 // between callers and callees. When a method overrides or implements 2394 // an abstract method in a supertype (superclass or interface), the 2395 // constraints are placed as if the supertype were the caller to the 2396 // overriding method. (This works well, since callers to the 2397 // supertype have already established agreement between themselves and 2398 // the supertype.) As a result of all this, a class can disagree with 2399 // its supertype about the meaning of a type name, as long as that 2400 // class neither calls a relevant method of the supertype, nor is 2401 // called (perhaps via an override) from the supertype. 2402 // 2403 // 2404 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2405 // 2406 // Make sure all class components (including arrays) in the given 2407 // signature will be resolved to the same class in both loaders. 2408 // Returns the name of the type that failed a loader constraint check, or 2409 // NULL if no constraint failed. No exception except OOME is thrown. 2410 // Arrays are not added to the loader constraint table, their elements are. 2411 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2412 Handle loader1, Handle loader2, 2413 bool is_method, TRAPS) { 2414 // Nothing to do if loaders are the same. 2415 if (oopDesc::equals(loader1(), loader2())) { 2416 return NULL; 2417 } 2418 2419 SignatureStream sig_strm(signature, is_method); 2420 while (!sig_strm.is_done()) { 2421 if (sig_strm.is_object()) { 2422 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2423 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2424 return sig; 2425 } 2426 } 2427 sig_strm.next(); 2428 } 2429 return NULL; 2430 } 2431 2432 2433 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2434 Symbol* signature, 2435 TRAPS) { 2436 methodHandle empty; 2437 assert(MethodHandles::is_signature_polymorphic(iid) && 2438 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2439 iid != vmIntrinsics::_invokeGeneric, 2440 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2441 2442 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2443 int index = invoke_method_table()->hash_to_index(hash); 2444 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2445 methodHandle m; 2446 if (spe == NULL || spe->method() == NULL) { 2447 spe = NULL; 2448 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2449 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2450 if (!Arguments::is_interpreter_only()) { 2451 // Generate a compiled form of the MH intrinsic. 2452 AdapterHandlerLibrary::create_native_wrapper(m); 2453 // Check if have the compiled code. 2454 if (!m->has_compiled_code()) { 2455 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2456 "Out of space in CodeCache for method handle intrinsic", empty); 2457 } 2458 } 2459 // Now grab the lock. We might have to throw away the new method, 2460 // if a racing thread has managed to install one at the same time. 2461 { 2462 MutexLocker ml(SystemDictionary_lock, THREAD); 2463 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2464 if (spe == NULL) 2465 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2466 if (spe->method() == NULL) 2467 spe->set_method(m()); 2468 } 2469 } 2470 2471 assert(spe != NULL && spe->method() != NULL, ""); 2472 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2473 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2474 "MH intrinsic invariant"); 2475 return spe->method(); 2476 } 2477 2478 // Helper for unpacking the return value from linkMethod and linkCallSite. 2479 static methodHandle unpack_method_and_appendix(Handle mname, 2480 Klass* accessing_klass, 2481 objArrayHandle appendix_box, 2482 Handle* appendix_result, 2483 TRAPS) { 2484 methodHandle empty; 2485 if (mname.not_null()) { 2486 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2487 if (m != NULL) { 2488 oop appendix = appendix_box->obj_at(0); 2489 if (TraceMethodHandles) { 2490 #ifndef PRODUCT 2491 ttyLocker ttyl; 2492 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2493 m->print(); 2494 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2495 tty->cr(); 2496 #endif //PRODUCT 2497 } 2498 (*appendix_result) = Handle(THREAD, appendix); 2499 // the target is stored in the cpCache and if a reference to this 2500 // MemberName is dropped we need a way to make sure the 2501 // class_loader containing this method is kept alive. 2502 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2503 this_key->record_dependency(m->method_holder()); 2504 return methodHandle(THREAD, m); 2505 } 2506 } 2507 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2508 return empty; 2509 } 2510 2511 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2512 Symbol* name, 2513 Symbol* signature, 2514 Klass* accessing_klass, 2515 Handle *appendix_result, 2516 Handle *method_type_result, 2517 TRAPS) { 2518 methodHandle empty; 2519 assert(THREAD->can_call_java() ,""); 2520 Handle method_type = 2521 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2522 2523 int ref_kind = JVM_REF_invokeVirtual; 2524 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2525 Handle name_str (THREAD, name_oop); 2526 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2527 assert(appendix_box->obj_at(0) == NULL, ""); 2528 2529 // This should not happen. JDK code should take care of that. 2530 if (accessing_klass == NULL || method_type.is_null()) { 2531 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2532 } 2533 2534 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2535 JavaCallArguments args; 2536 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2537 args.push_int(ref_kind); 2538 args.push_oop(Handle(THREAD, klass->java_mirror())); 2539 args.push_oop(name_str); 2540 args.push_oop(method_type); 2541 args.push_oop(appendix_box); 2542 JavaValue result(T_OBJECT); 2543 JavaCalls::call_static(&result, 2544 SystemDictionary::MethodHandleNatives_klass(), 2545 vmSymbols::linkMethod_name(), 2546 vmSymbols::linkMethod_signature(), 2547 &args, CHECK_(empty)); 2548 Handle mname(THREAD, (oop) result.get_jobject()); 2549 (*method_type_result) = method_type; 2550 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2551 } 2552 2553 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2554 // We must ensure that all class loaders everywhere will reach this class, for any client. 2555 // This is a safe bet for public classes in java.lang, such as Object and String. 2556 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2557 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2558 static bool is_always_visible_class(oop mirror) { 2559 Klass* klass = java_lang_Class::as_Klass(mirror); 2560 if (klass->is_objArray_klass()) { 2561 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2562 } 2563 if (klass->is_typeArray_klass()) { 2564 return true; // primitive array 2565 } 2566 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2567 return klass->is_public() && 2568 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2569 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2570 } 2571 2572 2573 // Return the Java mirror (java.lang.Class instance) for a single-character 2574 // descriptor. This result, when available, is the same as produced by the 2575 // heavier API point of the same name that takes a Symbol. 2576 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2577 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2578 } 2579 2580 // Find or construct the Java mirror (java.lang.Class instance) for a 2581 // for the given field type signature, as interpreted relative to the 2582 // given class loader. Handles primitives, void, references, arrays, 2583 // and all other reflectable types, except method types. 2584 // N.B. Code in reflection should use this entry point. 2585 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2586 Klass* accessing_klass, 2587 Handle class_loader, 2588 Handle protection_domain, 2589 SignatureStream::FailureMode failure_mode, 2590 TRAPS) { 2591 Handle empty; 2592 2593 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2594 "one or the other, or perhaps neither"); 2595 2596 Symbol* type = signature; 2597 2598 // What we have here must be a valid field descriptor, 2599 // and all valid field descriptors are supported. 2600 // Produce the same java.lang.Class that reflection reports. 2601 if (type->utf8_length() == 1) { 2602 2603 // It's a primitive. (Void has a primitive mirror too.) 2604 char ch = (char) type->byte_at(0); 2605 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2606 return Handle(THREAD, find_java_mirror_for_type(ch)); 2607 2608 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2609 2610 // It's a reference type. 2611 if (accessing_klass != NULL) { 2612 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2613 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2614 } 2615 Klass* constant_type_klass; 2616 if (failure_mode == SignatureStream::ReturnNull) { 2617 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2618 CHECK_(empty)); 2619 } else { 2620 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2621 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2622 throw_error, CHECK_(empty)); 2623 } 2624 if (constant_type_klass == NULL) { 2625 return Handle(); // report failure this way 2626 } 2627 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2628 2629 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2630 if (accessing_klass != NULL) { 2631 Klass* sel_klass = constant_type_klass; 2632 bool fold_type_to_class = true; 2633 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2634 fold_type_to_class, CHECK_(empty)); 2635 } 2636 2637 return mirror; 2638 2639 } 2640 2641 // Fall through to an error. 2642 assert(false, "unsupported mirror syntax"); 2643 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2644 } 2645 2646 2647 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2648 // signature, as interpreted relative to the given class loader. 2649 // Because of class loader constraints, all method handle usage must be 2650 // consistent with this loader. 2651 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2652 Klass* accessing_klass, 2653 TRAPS) { 2654 Handle empty; 2655 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2656 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2657 int index = invoke_method_table()->hash_to_index(hash); 2658 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2659 if (spe != NULL && spe->method_type() != NULL) { 2660 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2661 return Handle(THREAD, spe->method_type()); 2662 } else if (!THREAD->can_call_java()) { 2663 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2664 return Handle(); // do not attempt from within compiler, unless it was cached 2665 } 2666 2667 Handle class_loader, protection_domain; 2668 if (accessing_klass != NULL) { 2669 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2670 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2671 } 2672 bool can_be_cached = true; 2673 int npts = ArgumentCount(signature).size(); 2674 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2675 int arg = 0; 2676 Handle rt; // the return type from the signature 2677 ResourceMark rm(THREAD); 2678 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2679 oop mirror = NULL; 2680 if (can_be_cached) { 2681 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2682 mirror = ss.as_java_mirror(Handle(), Handle(), 2683 SignatureStream::ReturnNull, CHECK_(empty)); 2684 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2685 // Fall back to accessing_klass context. 2686 can_be_cached = false; 2687 } 2688 } 2689 if (!can_be_cached) { 2690 // Resolve, throwing a real error if it doesn't work. 2691 mirror = ss.as_java_mirror(class_loader, protection_domain, 2692 SignatureStream::NCDFError, CHECK_(empty)); 2693 } 2694 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string()); 2695 if (ss.at_return_type()) 2696 rt = Handle(THREAD, mirror); 2697 else 2698 pts->obj_at_put(arg++, mirror); 2699 2700 // Check accessibility. 2701 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2702 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2703 mirror = NULL; // safety 2704 // Emulate ConstantPool::verify_constant_pool_resolve. 2705 bool fold_type_to_class = true; 2706 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2707 fold_type_to_class, CHECK_(empty)); 2708 } 2709 } 2710 assert(arg == npts, ""); 2711 2712 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2713 JavaCallArguments args(Handle(THREAD, rt())); 2714 args.push_oop(pts); 2715 JavaValue result(T_OBJECT); 2716 JavaCalls::call_static(&result, 2717 SystemDictionary::MethodHandleNatives_klass(), 2718 vmSymbols::findMethodHandleType_name(), 2719 vmSymbols::findMethodHandleType_signature(), 2720 &args, CHECK_(empty)); 2721 Handle method_type(THREAD, (oop) result.get_jobject()); 2722 2723 if (can_be_cached) { 2724 // We can cache this MethodType inside the JVM. 2725 MutexLocker ml(SystemDictionary_lock, THREAD); 2726 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2727 if (spe == NULL) 2728 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2729 if (spe->method_type() == NULL) { 2730 spe->set_method_type(method_type()); 2731 } 2732 } 2733 2734 // report back to the caller with the MethodType 2735 return method_type; 2736 } 2737 2738 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2739 Klass* accessing_klass, 2740 TRAPS) { 2741 Handle empty; 2742 ResourceMark rm(THREAD); 2743 SignatureStream ss(signature, /*is_method=*/ false); 2744 if (!ss.is_done()) { 2745 Handle class_loader, protection_domain; 2746 if (accessing_klass != NULL) { 2747 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2748 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2749 } 2750 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2751 ss.next(); 2752 if (ss.is_done()) { 2753 return Handle(THREAD, mirror); 2754 } 2755 } 2756 return empty; 2757 } 2758 2759 // Ask Java code to find or construct a method handle constant. 2760 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2761 int ref_kind, //e.g., JVM_REF_invokeVirtual 2762 Klass* callee, 2763 Symbol* name, 2764 Symbol* signature, 2765 TRAPS) { 2766 Handle empty; 2767 if (caller == NULL) { 2768 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2769 } 2770 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2771 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2772 2773 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2774 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2775 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2776 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2777 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2778 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2779 2780 if (ref_kind == JVM_REF_invokeVirtual && 2781 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() && 2782 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) { 2783 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact(). 2784 // They are public signature polymorphic methods, but require appendix argument 2785 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them 2786 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2787 } else { 2788 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); 2789 } 2790 2791 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2792 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2793 2794 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2795 JavaCallArguments args; 2796 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2797 args.push_int(ref_kind); 2798 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2799 args.push_oop(name_str); 2800 args.push_oop(type); 2801 JavaValue result(T_OBJECT); 2802 JavaCalls::call_static(&result, 2803 SystemDictionary::MethodHandleNatives_klass(), 2804 vmSymbols::linkMethodHandleConstant_name(), 2805 vmSymbols::linkMethodHandleConstant_signature(), 2806 &args, CHECK_(empty)); 2807 return Handle(THREAD, (oop) result.get_jobject()); 2808 } 2809 2810 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry 2811 Handle SystemDictionary::link_dynamic_constant(Klass* caller, 2812 int condy_index, 2813 Handle bootstrap_specifier, 2814 Symbol* name, 2815 Symbol* type, 2816 TRAPS) { 2817 Handle empty; 2818 Handle bsm, info; 2819 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2820 bsm = bootstrap_specifier; 2821 } else { 2822 assert(bootstrap_specifier->is_objArray(), ""); 2823 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2824 assert(args->length() == 2, ""); 2825 bsm = Handle(THREAD, args->obj_at(0)); 2826 info = Handle(THREAD, args->obj_at(1)); 2827 } 2828 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2829 "caller must supply a valid BSM"); 2830 2831 // This should not happen. JDK code should take care of that. 2832 if (caller == NULL) { 2833 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); 2834 } 2835 2836 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2837 2838 // Resolve the constant type in the context of the caller class 2839 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, 2840 CHECK_(empty)); 2841 2842 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) 2843 JavaCallArguments args; 2844 args.push_oop(Handle(THREAD, caller->java_mirror())); 2845 args.push_int(condy_index); 2846 args.push_oop(bsm); 2847 args.push_oop(constant_name); 2848 args.push_oop(type_mirror); 2849 args.push_oop(info); 2850 JavaValue result(T_OBJECT); 2851 JavaCalls::call_static(&result, 2852 SystemDictionary::MethodHandleNatives_klass(), 2853 vmSymbols::linkDynamicConstant_name(), 2854 vmSymbols::linkDynamicConstant_signature(), 2855 &args, CHECK_(empty)); 2856 2857 return Handle(THREAD, (oop) result.get_jobject()); 2858 } 2859 2860 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2861 // name and signature, as interpreted relative to the given class loader. 2862 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2863 int indy_index, 2864 Handle bootstrap_specifier, 2865 Symbol* name, 2866 Symbol* type, 2867 Handle *appendix_result, 2868 Handle *method_type_result, 2869 TRAPS) { 2870 methodHandle empty; 2871 Handle bsm, info; 2872 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2873 bsm = bootstrap_specifier; 2874 } else { 2875 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2876 assert(args->length() == 2, ""); 2877 bsm = Handle(THREAD, args->obj_at(0)); 2878 info = Handle(THREAD, args->obj_at(1)); 2879 } 2880 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2881 "caller must supply a valid BSM"); 2882 2883 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2884 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2885 2886 // This should not happen. JDK code should take care of that. 2887 if (caller == NULL || method_type.is_null()) { 2888 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2889 } 2890 2891 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2892 assert(appendix_box->obj_at(0) == NULL, ""); 2893 2894 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2895 JavaCallArguments args; 2896 args.push_oop(Handle(THREAD, caller->java_mirror())); 2897 args.push_int(indy_index); 2898 args.push_oop(bsm); 2899 args.push_oop(method_name); 2900 args.push_oop(method_type); 2901 args.push_oop(info); 2902 args.push_oop(appendix_box); 2903 JavaValue result(T_OBJECT); 2904 JavaCalls::call_static(&result, 2905 SystemDictionary::MethodHandleNatives_klass(), 2906 vmSymbols::linkCallSite_name(), 2907 vmSymbols::linkCallSite_signature(), 2908 &args, CHECK_(empty)); 2909 Handle mname(THREAD, (oop) result.get_jobject()); 2910 (*method_type_result) = method_type; 2911 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2912 } 2913 2914 // Protection domain cache table handling 2915 2916 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2917 return _pd_cache_table->get(protection_domain); 2918 } 2919 2920 #if INCLUDE_CDS 2921 void SystemDictionary::reorder_dictionary_for_sharing() { 2922 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); 2923 } 2924 #endif 2925 2926 size_t SystemDictionary::count_bytes_for_buckets() { 2927 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); 2928 } 2929 2930 size_t SystemDictionary::count_bytes_for_table() { 2931 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); 2932 } 2933 2934 void SystemDictionary::copy_buckets(char* top, char* end) { 2935 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2936 } 2937 2938 void SystemDictionary::copy_table(char* top, char* end) { 2939 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2940 } 2941 2942 // ---------------------------------------------------------------------------- 2943 void SystemDictionary::print_shared(outputStream *st) { 2944 shared_dictionary()->print_on(st); 2945 } 2946 2947 void SystemDictionary::print_on(outputStream *st) { 2948 if (shared_dictionary() != NULL) { 2949 st->print_cr("Shared Dictionary"); 2950 shared_dictionary()->print_on(st); 2951 st->cr(); 2952 } 2953 2954 GCMutexLocker mu(SystemDictionary_lock); 2955 2956 ClassLoaderDataGraph::print_dictionary(st); 2957 2958 // Placeholders 2959 placeholders()->print_on(st); 2960 st->cr(); 2961 2962 // loader constraints - print under SD_lock 2963 constraints()->print_on(st); 2964 st->cr(); 2965 2966 _pd_cache_table->print_on(st); 2967 st->cr(); 2968 } 2969 2970 void SystemDictionary::verify() { 2971 guarantee(constraints() != NULL, 2972 "Verify of loader constraints failed"); 2973 guarantee(placeholders()->number_of_entries() >= 0, 2974 "Verify of placeholders failed"); 2975 2976 GCMutexLocker mu(SystemDictionary_lock); 2977 2978 // Verify dictionary 2979 ClassLoaderDataGraph::verify_dictionary(); 2980 2981 placeholders()->verify(); 2982 2983 // Verify constraint table 2984 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2985 constraints()->verify(placeholders()); 2986 2987 _pd_cache_table->verify(); 2988 } 2989 2990 void SystemDictionary::dump(outputStream *st, bool verbose) { 2991 assert_locked_or_safepoint(SystemDictionary_lock); 2992 if (verbose) { 2993 print_on(st); 2994 } else { 2995 if (shared_dictionary() != NULL) { 2996 shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); 2997 } 2998 ClassLoaderDataGraph::print_dictionary_statistics(st); 2999 placeholders()->print_table_statistics(st, "Placeholder Table"); 3000 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 3001 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 3002 } 3003 } 3004 3005 // Utility for dumping dictionaries. 3006 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 3007 DCmdWithParser(output, heap), 3008 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 3009 "BOOLEAN", false, "false") { 3010 _dcmdparser.add_dcmd_option(&_verbose); 3011 } 3012 3013 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 3014 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 3015 _verbose.value()); 3016 VMThread::execute(&dumper); 3017 } 3018 3019 int SystemDictionaryDCmd::num_arguments() { 3020 ResourceMark rm; 3021 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 3022 if (dcmd != NULL) { 3023 DCmdMark mark(dcmd); 3024 return dcmd->_dcmdparser.num_arguments(); 3025 } else { 3026 return 0; 3027 } 3028 } 3029 3030 class CombineDictionariesClosure : public CLDClosure { 3031 private: 3032 Dictionary* _master_dictionary; 3033 public: 3034 CombineDictionariesClosure(Dictionary* master_dictionary) : 3035 _master_dictionary(master_dictionary) {} 3036 void do_cld(ClassLoaderData* cld) { 3037 ResourceMark rm; 3038 if (cld->is_anonymous()) { 3039 return; 3040 } 3041 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 3042 for (int i = 0; i < cld->dictionary()->table_size(); ++i) { 3043 Dictionary* curr_dictionary = cld->dictionary(); 3044 DictionaryEntry* p = curr_dictionary->bucket(i); 3045 while (p != NULL) { 3046 Symbol* name = p->instance_klass()->name(); 3047 unsigned int d_hash = _master_dictionary->compute_hash(name); 3048 int d_index = _master_dictionary->hash_to_index(d_hash); 3049 DictionaryEntry* next = p->next(); 3050 if (p->literal()->class_loader_data() != cld) { 3051 // This is an initiating class loader entry; don't use it 3052 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); 3053 curr_dictionary->free_entry(p); 3054 } else { 3055 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); 3056 curr_dictionary->unlink_entry(p); 3057 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. 3058 _master_dictionary->add_entry(d_index, p); 3059 } 3060 p = next; 3061 } 3062 *curr_dictionary->bucket_addr(i) = NULL; 3063 } 3064 } 3065 } 3066 }; 3067 3068 // Combining platform and system loader dictionaries into boot loader dictionary. 3069 // During run time, we only have one shared dictionary. 3070 void SystemDictionary::combine_shared_dictionaries() { 3071 assert(DumpSharedSpaces, "dump time only"); 3072 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); 3073 CombineDictionariesClosure cdc(master_dictionary); 3074 ClassLoaderDataGraph::cld_do(&cdc); 3075 3076 // These tables are no longer valid or necessary. Keeping them around will 3077 // cause SystemDictionary::verify() to fail. Let's empty them. 3078 _placeholders = new PlaceholderTable(_placeholder_table_size); 3079 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 3080 3081 NOT_PRODUCT(SystemDictionary::verify()); 3082 } 3083 3084 // caller needs ResourceMark 3085 const char* SystemDictionary::loader_name(const oop loader) { 3086 return ((loader) == NULL ? "<bootloader>" : 3087 InstanceKlass::cast((loader)->klass())->name()->as_C_string()); 3088 } 3089 3090 // caller needs ResourceMark 3091 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { 3092 return (loader_data->class_loader() == NULL ? "<bootloader>" : 3093 SystemDictionary::loader_name(loader_data->class_loader())); 3094 } 3095 3096 void SystemDictionary::initialize_oop_storage() { 3097 _vm_weak_oop_storage = 3098 new OopStorage("VM Weak Oop Handles", 3099 VMWeakAlloc_lock, 3100 VMWeakActive_lock); 3101 } 3102 3103 OopStorage* SystemDictionary::vm_weak_oop_storage() { 3104 assert(_vm_weak_oop_storage != NULL, "Uninitialized"); 3105 return _vm_weak_oop_storage; 3106 }