1 /* 2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "jvm.h" 27 #include "aot/aotLoader.hpp" 28 #include "classfile/classFileParser.hpp" 29 #include "classfile/classFileStream.hpp" 30 #include "classfile/classLoader.hpp" 31 #include "classfile/classLoaderData.inline.hpp" 32 #include "classfile/classLoaderExt.hpp" 33 #include "classfile/dictionary.hpp" 34 #include "classfile/javaClasses.inline.hpp" 35 #include "classfile/klassFactory.hpp" 36 #include "classfile/loaderConstraints.hpp" 37 #include "classfile/packageEntry.hpp" 38 #include "classfile/placeholders.hpp" 39 #include "classfile/protectionDomainCache.hpp" 40 #include "classfile/resolutionErrors.hpp" 41 #include "classfile/stringTable.hpp" 42 #include "classfile/systemDictionary.hpp" 43 #include "classfile/vmSymbols.hpp" 44 #include "code/codeCache.hpp" 45 #include "compiler/compileBroker.hpp" 46 #include "gc/shared/gcTraceTime.inline.hpp" 47 #include "gc/shared/oopStorage.inline.hpp" 48 #include "interpreter/bytecodeStream.hpp" 49 #include "interpreter/interpreter.hpp" 50 #include "jfr/jfrEvents.hpp" 51 #include "logging/log.hpp" 52 #include "logging/logStream.hpp" 53 #include "memory/filemap.hpp" 54 #include "memory/metaspaceClosure.hpp" 55 #include "memory/oopFactory.hpp" 56 #include "memory/resourceArea.hpp" 57 #include "oops/access.inline.hpp" 58 #include "oops/instanceKlass.hpp" 59 #include "oops/instanceRefKlass.hpp" 60 #include "oops/klass.inline.hpp" 61 #include "oops/method.inline.hpp" 62 #include "oops/methodData.hpp" 63 #include "oops/objArrayKlass.hpp" 64 #include "oops/objArrayOop.inline.hpp" 65 #include "oops/oop.inline.hpp" 66 #include "oops/symbol.hpp" 67 #include "oops/typeArrayKlass.hpp" 68 #include "prims/jvmtiEnvBase.hpp" 69 #include "prims/resolvedMethodTable.hpp" 70 #include "prims/methodHandles.hpp" 71 #include "runtime/arguments.hpp" 72 #include "runtime/arguments_ext.hpp" 73 #include "runtime/biasedLocking.hpp" 74 #include "runtime/fieldType.hpp" 75 #include "runtime/handles.inline.hpp" 76 #include "runtime/java.hpp" 77 #include "runtime/javaCalls.hpp" 78 #include "runtime/mutexLocker.hpp" 79 #include "runtime/orderAccess.hpp" 80 #include "runtime/sharedRuntime.hpp" 81 #include "runtime/signature.hpp" 82 #include "services/classLoadingService.hpp" 83 #include "services/diagnosticCommand.hpp" 84 #include "services/threadService.hpp" 85 #include "utilities/macros.hpp" 86 #if INCLUDE_CDS 87 #include "classfile/systemDictionaryShared.hpp" 88 #endif 89 #if INCLUDE_JVMCI 90 #include "jvmci/jvmciRuntime.hpp" 91 #endif 92 93 PlaceholderTable* SystemDictionary::_placeholders = NULL; 94 Dictionary* SystemDictionary::_shared_dictionary = NULL; 95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; 99 100 int SystemDictionary::_number_of_modifications = 0; 101 oop SystemDictionary::_system_loader_lock_obj = NULL; 102 103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 104 = { NULL /*, NULL...*/ }; 105 106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 107 108 oop SystemDictionary::_java_system_loader = NULL; 109 oop SystemDictionary::_java_platform_loader = NULL; 110 111 bool SystemDictionary::_has_checkPackageAccess = false; 112 113 // Default ProtectionDomainCacheSize value 114 115 const int defaultProtectionDomainCacheSize = 1009; 116 117 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL; 118 119 120 // ---------------------------------------------------------------------------- 121 // Java-level SystemLoader and PlatformLoader 122 123 oop SystemDictionary::java_system_loader() { 124 return _java_system_loader; 125 } 126 127 oop SystemDictionary::java_platform_loader() { 128 return _java_platform_loader; 129 } 130 131 void SystemDictionary::compute_java_loaders(TRAPS) { 132 JavaValue result(T_OBJECT); 133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); 134 JavaCalls::call_static(&result, 135 class_loader_klass, 136 vmSymbols::getSystemClassLoader_name(), 137 vmSymbols::void_classloader_signature(), 138 CHECK); 139 140 _java_system_loader = (oop)result.get_jobject(); 141 142 JavaCalls::call_static(&result, 143 class_loader_klass, 144 vmSymbols::getPlatformClassLoader_name(), 145 vmSymbols::void_classloader_signature(), 146 CHECK); 147 148 _java_platform_loader = (oop)result.get_jobject(); 149 } 150 151 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) { 152 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 153 return ClassLoaderDataGraph::find_or_create(class_loader); 154 } 155 156 // ---------------------------------------------------------------------------- 157 // Parallel class loading check 158 159 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 160 if (class_loader.is_null()) return true; 161 if (AlwaysLockClassLoader) return false; 162 return java_lang_ClassLoader::parallelCapable(class_loader()); 163 } 164 // ---------------------------------------------------------------------------- 165 // ParallelDefineClass flag does not apply to bootclass loader 166 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 167 if (class_loader.is_null()) return false; 168 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 169 return true; 170 } 171 return false; 172 } 173 174 // Returns true if the passed class loader is the builtin application class loader 175 // or a custom system class loader. A customer system class loader can be 176 // specified via -Djava.system.class.loader. 177 bool SystemDictionary::is_system_class_loader(oop class_loader) { 178 if (class_loader == NULL) { 179 return false; 180 } 181 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 182 oopDesc::equals(class_loader, _java_system_loader)); 183 } 184 185 // Returns true if the passed class loader is the platform class loader. 186 bool SystemDictionary::is_platform_class_loader(oop class_loader) { 187 if (class_loader == NULL) { 188 return false; 189 } 190 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 191 } 192 193 // ---------------------------------------------------------------------------- 194 // Resolving of classes 195 196 // Forwards to resolve_or_null 197 198 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 199 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 200 if (HAS_PENDING_EXCEPTION || klass == NULL) { 201 // can return a null klass 202 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); 203 } 204 return klass; 205 } 206 207 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 208 bool throw_error, 209 Klass* klass, TRAPS) { 210 if (HAS_PENDING_EXCEPTION) { 211 // If we have a pending exception we forward it to the caller, unless throw_error is true, 212 // in which case we have to check whether the pending exception is a ClassNotFoundException, 213 // and if so convert it to a NoClassDefFoundError 214 // And chain the original ClassNotFoundException 215 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 216 ResourceMark rm(THREAD); 217 assert(klass == NULL, "Should not have result with exception pending"); 218 Handle e(THREAD, PENDING_EXCEPTION); 219 CLEAR_PENDING_EXCEPTION; 220 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 221 } else { 222 return NULL; 223 } 224 } 225 // Class not found, throw appropriate error or exception depending on value of throw_error 226 if (klass == NULL) { 227 ResourceMark rm(THREAD); 228 if (throw_error) { 229 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 230 } else { 231 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 232 } 233 } 234 return klass; 235 } 236 237 238 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 239 bool throw_error, TRAPS) 240 { 241 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 242 } 243 244 245 // Forwards to resolve_instance_class_or_null 246 247 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 248 if (FieldType::is_array(class_name)) { 249 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 250 } else if (FieldType::is_obj(class_name)) { 251 ResourceMark rm(THREAD); 252 // Ignore wrapping L and ;. 253 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 254 class_name->utf8_length() - 2, CHECK_NULL); 255 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 256 } else { 257 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 258 } 259 } 260 261 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 262 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 263 } 264 265 // Forwards to resolve_instance_class_or_null 266 267 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 268 Handle class_loader, 269 Handle protection_domain, 270 TRAPS) { 271 assert(FieldType::is_array(class_name), "must be array"); 272 Klass* k = NULL; 273 FieldArrayInfo fd; 274 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 275 // of this call 276 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 277 if (t == T_OBJECT) { 278 // naked oop "k" is OK here -- we assign back into it 279 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 280 class_loader, 281 protection_domain, 282 CHECK_NULL); 283 if (k != NULL) { 284 k = k->array_klass(fd.dimension(), CHECK_NULL); 285 } 286 } else { 287 k = Universe::typeArrayKlassObj(t); 288 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 289 } 290 return k; 291 } 292 293 294 // Must be called for any super-class or super-interface resolution 295 // during class definition to allow class circularity checking 296 // super-interface callers: 297 // parse_interfaces - for defineClass & jvmtiRedefineClasses 298 // super-class callers: 299 // ClassFileParser - for defineClass & jvmtiRedefineClasses 300 // load_shared_class - while loading a class from shared archive 301 // resolve_instance_class_or_null: 302 // via: handle_parallel_super_load 303 // when resolving a class that has an existing placeholder with 304 // a saved superclass [i.e. a defineClass is currently in progress] 305 // if another thread is trying to resolve the class, it must do 306 // super-class checks on its own thread to catch class circularity 307 // This last call is critical in class circularity checking for cases 308 // where classloading is delegated to different threads and the 309 // classloader lock is released. 310 // Take the case: Base->Super->Base 311 // 1. If thread T1 tries to do a defineClass of class Base 312 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 313 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 314 // so it tries to load Super 315 // 3. If we load the class internally, or user classloader uses same thread 316 // loadClassFromxxx or defineClass via parseClassFile Super ... 317 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 318 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 319 // 3.4 calls resolve_super_or_fail Base 320 // 3.5 finds T1,Base -> throws class circularity 321 //OR 4. If T2 tries to resolve Super via defineClass Super ... 322 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 323 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 324 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 325 // 4.4 finds T2, Super -> throws class circularity 326 // Must be called, even if superclass is null, since this is 327 // where the placeholder entry is created which claims this 328 // thread is loading this class/classloader. 329 // Be careful when modifying this code: once you have run 330 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), 331 // you need to find_and_remove it before returning. 332 // So be careful to not exit with a CHECK_ macro betweeen these calls. 333 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 334 Symbol* class_name, 335 Handle class_loader, 336 Handle protection_domain, 337 bool is_superclass, 338 TRAPS) { 339 #if INCLUDE_CDS 340 if (DumpSharedSpaces) { 341 // Special processing for CDS dump time. 342 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 343 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 344 if (k) { 345 return k; 346 } 347 } 348 #endif // INCLUDE_CDS 349 350 // Double-check, if child class is already loaded, just return super-class,interface 351 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader 352 // dictionary. 353 // Make sure there's a placeholder for the *child* before resolving. 354 // Used as a claim that this thread is currently loading superclass/classloader 355 // Used here for ClassCircularity checks and also for heap verification 356 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). 357 // Must check ClassCircularity before checking if super class is already loaded. 358 // 359 // We might not already have a placeholder if this child_name was 360 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 361 // the name of the class might not be known until the stream is actually 362 // parsed. 363 // Bugs 4643874, 4715493 364 365 ClassLoaderData* loader_data = class_loader_data(class_loader); 366 Dictionary* dictionary = loader_data->dictionary(); 367 unsigned int d_hash = dictionary->compute_hash(child_name); 368 unsigned int p_hash = placeholders()->compute_hash(child_name); 369 int p_index = placeholders()->hash_to_index(p_hash); 370 // can't throw error holding a lock 371 bool child_already_loaded = false; 372 bool throw_circularity_error = false; 373 { 374 MutexLocker mu(SystemDictionary_lock, THREAD); 375 Klass* childk = find_class(d_hash, child_name, dictionary); 376 Klass* quicksuperk; 377 // to support // loading: if child done loading, just return superclass 378 // if class_name, & class_loader don't match: 379 // if initial define, SD update will give LinkageError 380 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 381 // so we don't throw an exception here. 382 // see: nsk redefclass014 & java.lang.instrument Instrument032 383 if ((childk != NULL ) && (is_superclass) && 384 ((quicksuperk = childk->super()) != NULL) && 385 386 ((quicksuperk->name() == class_name) && 387 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) { 388 return quicksuperk; 389 } else { 390 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 391 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 392 throw_circularity_error = true; 393 } 394 } 395 if (!throw_circularity_error) { 396 // Be careful not to exit resolve_super 397 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 398 } 399 } 400 if (throw_circularity_error) { 401 ResourceMark rm(THREAD); 402 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 403 } 404 405 // java.lang.Object should have been found above 406 assert(class_name != NULL, "null super class for resolving"); 407 // Resolve the super class or interface, check results on return 408 Klass* superk = SystemDictionary::resolve_or_null(class_name, 409 class_loader, 410 protection_domain, 411 THREAD); 412 413 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 414 // It is no longer necessary to keep the placeholder table alive until update_dictionary 415 // or error. GC used to walk the placeholder table as strong roots. 416 // The instanceKlass is kept alive because the class loader is on the stack, 417 // which keeps the loader_data alive, as well as all instanceKlasses in 418 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 419 { 420 MutexLocker mu(SystemDictionary_lock, THREAD); 421 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 422 SystemDictionary_lock->notify_all(); 423 } 424 if (HAS_PENDING_EXCEPTION || superk == NULL) { 425 // can null superk 426 superk = handle_resolution_exception(class_name, true, superk, THREAD); 427 } 428 429 return superk; 430 } 431 432 void SystemDictionary::validate_protection_domain(InstanceKlass* klass, 433 Handle class_loader, 434 Handle protection_domain, 435 TRAPS) { 436 if(!has_checkPackageAccess()) return; 437 438 // Now we have to call back to java to check if the initating class has access 439 JavaValue result(T_VOID); 440 LogTarget(Debug, protectiondomain) lt; 441 if (lt.is_enabled()) { 442 ResourceMark rm; 443 // Print out trace information 444 LogStream ls(lt); 445 ls.print_cr("Checking package access"); 446 ls.print("class loader: "); class_loader()->print_value_on(&ls); 447 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls); 448 ls.print(" loading: "); klass->print_value_on(&ls); 449 ls.cr(); 450 } 451 452 // This handle and the class_loader handle passed in keeps this class from 453 // being unloaded through several GC points. 454 // The class_loader handle passed in is the initiating loader. 455 Handle mirror(THREAD, klass->java_mirror()); 456 457 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); 458 JavaCalls::call_special(&result, 459 class_loader, 460 system_loader, 461 vmSymbols::checkPackageAccess_name(), 462 vmSymbols::class_protectiondomain_signature(), 463 mirror, 464 protection_domain, 465 THREAD); 466 467 if (HAS_PENDING_EXCEPTION) { 468 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 469 } else { 470 log_debug(protectiondomain)("granted"); 471 } 472 473 if (HAS_PENDING_EXCEPTION) return; 474 475 // If no exception has been thrown, we have validated the protection domain 476 // Insert the protection domain of the initiating class into the set. 477 { 478 ClassLoaderData* loader_data = class_loader_data(class_loader); 479 Dictionary* dictionary = loader_data->dictionary(); 480 481 Symbol* kn = klass->name(); 482 unsigned int d_hash = dictionary->compute_hash(kn); 483 484 MutexLocker mu(SystemDictionary_lock, THREAD); 485 int d_index = dictionary->hash_to_index(d_hash); 486 dictionary->add_protection_domain(d_index, d_hash, klass, 487 protection_domain, THREAD); 488 } 489 } 490 491 // We only get here if this thread finds that another thread 492 // has already claimed the placeholder token for the current operation, 493 // but that other thread either never owned or gave up the 494 // object lock 495 // Waits on SystemDictionary_lock to indicate placeholder table updated 496 // On return, caller must recheck placeholder table state 497 // 498 // We only get here if 499 // 1) custom classLoader, i.e. not bootstrap classloader 500 // 2) custom classLoader has broken the class loader objectLock 501 // so another thread got here in parallel 502 // 503 // lockObject must be held. 504 // Complicated dance due to lock ordering: 505 // Must first release the classloader object lock to 506 // allow initial definer to complete the class definition 507 // and to avoid deadlock 508 // Reclaim classloader lock object with same original recursion count 509 // Must release SystemDictionary_lock after notify, since 510 // class loader lock must be claimed before SystemDictionary_lock 511 // to prevent deadlocks 512 // 513 // The notify allows applications that did an untimed wait() on 514 // the classloader object lock to not hang. 515 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 516 assert_lock_strong(SystemDictionary_lock); 517 518 bool calledholdinglock 519 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 520 assert(calledholdinglock,"must hold lock for notify"); 521 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 522 ObjectSynchronizer::notifyall(lockObject, THREAD); 523 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 524 SystemDictionary_lock->wait(); 525 SystemDictionary_lock->unlock(); 526 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 527 SystemDictionary_lock->lock(); 528 } 529 530 // If the class in is in the placeholder table, class loading is in progress 531 // For cases where the application changes threads to load classes, it 532 // is critical to ClassCircularity detection that we try loading 533 // the superclass on the same thread internally, so we do parallel 534 // super class loading here. 535 // This also is critical in cases where the original thread gets stalled 536 // even in non-circularity situations. 537 // Note: must call resolve_super_or_fail even if null super - 538 // to force placeholder entry creation for this class for circularity detection 539 // Caller must check for pending exception 540 // Returns non-null Klass* if other thread has completed load 541 // and we are done, 542 // If return null Klass* and no pending exception, the caller must load the class 543 InstanceKlass* SystemDictionary::handle_parallel_super_load( 544 Symbol* name, Symbol* superclassname, Handle class_loader, 545 Handle protection_domain, Handle lockObject, TRAPS) { 546 547 ClassLoaderData* loader_data = class_loader_data(class_loader); 548 Dictionary* dictionary = loader_data->dictionary(); 549 unsigned int d_hash = dictionary->compute_hash(name); 550 unsigned int p_hash = placeholders()->compute_hash(name); 551 int p_index = placeholders()->hash_to_index(p_hash); 552 553 // superk is not used, resolve_super called for circularity check only 554 // This code is reached in two situations. One if this thread 555 // is loading the same class twice (e.g. ClassCircularity, or 556 // java.lang.instrument). 557 // The second is if another thread started the resolve_super first 558 // and has not yet finished. 559 // In both cases the original caller will clean up the placeholder 560 // entry on error. 561 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 562 superclassname, 563 class_loader, 564 protection_domain, 565 true, 566 CHECK_NULL); 567 568 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 569 // Serial class loaders and bootstrap classloader do wait for superclass loads 570 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 571 MutexLocker mu(SystemDictionary_lock, THREAD); 572 // Check if classloading completed while we were loading superclass or waiting 573 return find_class(d_hash, name, dictionary); 574 } 575 576 // must loop to both handle other placeholder updates 577 // and spurious notifications 578 bool super_load_in_progress = true; 579 PlaceholderEntry* placeholder; 580 while (super_load_in_progress) { 581 MutexLocker mu(SystemDictionary_lock, THREAD); 582 // Check if classloading completed while we were loading superclass or waiting 583 InstanceKlass* check = find_class(d_hash, name, dictionary); 584 if (check != NULL) { 585 // Klass is already loaded, so just return it 586 return check; 587 } else { 588 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 589 if (placeholder && placeholder->super_load_in_progress() ){ 590 // We only get here if the application has released the 591 // classloader lock when another thread was in the middle of loading a 592 // superclass/superinterface for this class, and now 593 // this thread is also trying to load this class. 594 // To minimize surprises, the first thread that started to 595 // load a class should be the one to complete the loading 596 // with the classfile it initially expected. 597 // This logic has the current thread wait once it has done 598 // all the superclass/superinterface loading it can, until 599 // the original thread completes the class loading or fails 600 // If it completes we will use the resulting InstanceKlass 601 // which we will find below in the systemDictionary. 602 // We also get here for parallel bootstrap classloader 603 if (class_loader.is_null()) { 604 SystemDictionary_lock->wait(); 605 } else { 606 double_lock_wait(lockObject, THREAD); 607 } 608 } else { 609 // If not in SD and not in PH, other thread's load must have failed 610 super_load_in_progress = false; 611 } 612 } 613 } 614 return NULL; 615 } 616 617 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) { 618 assert(event != NULL, "invariant"); 619 assert(k != NULL, "invariant"); 620 assert(event->should_commit(), "invariant"); 621 event->set_loadedClass(k); 622 event->set_definingClassLoader(k->class_loader_data()); 623 event->set_initiatingClassLoader(init_cld); 624 event->commit(); 625 } 626 627 628 // Be careful when modifying this code: once you have run 629 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), 630 // you need to find_and_remove it before returning. 631 // So be careful to not exit with a CHECK_ macro betweeen these calls. 632 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 633 Handle class_loader, 634 Handle protection_domain, 635 TRAPS) { 636 assert(name != NULL && !FieldType::is_array(name) && 637 !FieldType::is_obj(name), "invalid class name"); 638 639 EventClassLoad class_load_start_event; 640 641 HandleMark hm(THREAD); 642 643 // Fix for 4474172; see evaluation for more details 644 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 645 ClassLoaderData* loader_data = register_loader(class_loader); 646 Dictionary* dictionary = loader_data->dictionary(); 647 unsigned int d_hash = dictionary->compute_hash(name); 648 649 // Do lookup to see if class already exist and the protection domain 650 // has the right access 651 // This call uses find which checks protection domain already matches 652 // All subsequent calls use find_class, and set has_loaded_class so that 653 // before we return a result we call out to java to check for valid protection domain 654 // to allow returning the Klass* and add it to the pd_set if it is valid 655 { 656 Klass* probe = dictionary->find(d_hash, name, protection_domain); 657 if (probe != NULL) return probe; 658 } 659 660 // Non-bootstrap class loaders will call out to class loader and 661 // define via jvm/jni_DefineClass which will acquire the 662 // class loader object lock to protect against multiple threads 663 // defining the class in parallel by accident. 664 // This lock must be acquired here so the waiter will find 665 // any successful result in the SystemDictionary and not attempt 666 // the define. 667 // ParallelCapable Classloaders and the bootstrap classloader 668 // do not acquire lock here. 669 bool DoObjectLock = true; 670 if (is_parallelCapable(class_loader)) { 671 DoObjectLock = false; 672 } 673 674 unsigned int p_hash = placeholders()->compute_hash(name); 675 int p_index = placeholders()->hash_to_index(p_hash); 676 677 // Class is not in SystemDictionary so we have to do loading. 678 // Make sure we are synchronized on the class loader before we proceed 679 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 680 check_loader_lock_contention(lockObject, THREAD); 681 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 682 683 // Check again (after locking) if class already exist in SystemDictionary 684 bool class_has_been_loaded = false; 685 bool super_load_in_progress = false; 686 bool havesupername = false; 687 InstanceKlass* k = NULL; 688 PlaceholderEntry* placeholder; 689 Symbol* superclassname = NULL; 690 691 assert(THREAD->can_call_java(), 692 "can not load classes with compiler thread: class=%s, classloader=%s", 693 name->as_C_string(), 694 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 695 { 696 MutexLocker mu(SystemDictionary_lock, THREAD); 697 InstanceKlass* check = find_class(d_hash, name, dictionary); 698 if (check != NULL) { 699 // Klass is already loaded, so just return it 700 class_has_been_loaded = true; 701 k = check; 702 } else { 703 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 704 if (placeholder && placeholder->super_load_in_progress()) { 705 super_load_in_progress = true; 706 if (placeholder->havesupername() == true) { 707 superclassname = placeholder->supername(); 708 havesupername = true; 709 } 710 } 711 } 712 } 713 714 // If the class is in the placeholder table, class loading is in progress 715 if (super_load_in_progress && havesupername==true) { 716 k = handle_parallel_super_load(name, 717 superclassname, 718 class_loader, 719 protection_domain, 720 lockObject, THREAD); 721 if (HAS_PENDING_EXCEPTION) { 722 return NULL; 723 } 724 if (k != NULL) { 725 class_has_been_loaded = true; 726 } 727 } 728 729 bool throw_circularity_error = false; 730 if (!class_has_been_loaded) { 731 bool load_instance_added = false; 732 733 // add placeholder entry to record loading instance class 734 // Five cases: 735 // All cases need to prevent modifying bootclasssearchpath 736 // in parallel with a classload of same classname 737 // Redefineclasses uses existence of the placeholder for the duration 738 // of the class load to prevent concurrent redefinition of not completely 739 // defined classes. 740 // case 1. traditional classloaders that rely on the classloader object lock 741 // - no other need for LOAD_INSTANCE 742 // case 2. traditional classloaders that break the classloader object lock 743 // as a deadlock workaround. Detection of this case requires that 744 // this check is done while holding the classloader object lock, 745 // and that lock is still held when calling classloader's loadClass. 746 // For these classloaders, we ensure that the first requestor 747 // completes the load and other requestors wait for completion. 748 // case 3. Bootstrap classloader - don't own objectLocker 749 // This classloader supports parallelism at the classloader level, 750 // but only allows a single load of a class/classloader pair. 751 // No performance benefit and no deadlock issues. 752 // case 4. parallelCapable user level classloaders - without objectLocker 753 // Allow parallel classloading of a class/classloader pair 754 755 { 756 MutexLocker mu(SystemDictionary_lock, THREAD); 757 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 758 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 759 if (oldprobe) { 760 // only need check_seen_thread once, not on each loop 761 // 6341374 java/lang/Instrument with -Xcomp 762 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 763 throw_circularity_error = true; 764 } else { 765 // case 1: traditional: should never see load_in_progress. 766 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 767 768 // case 3: bootstrap classloader: prevent futile classloading, 769 // wait on first requestor 770 if (class_loader.is_null()) { 771 SystemDictionary_lock->wait(); 772 } else { 773 // case 2: traditional with broken classloader lock. wait on first 774 // requestor. 775 double_lock_wait(lockObject, THREAD); 776 } 777 // Check if classloading completed while we were waiting 778 InstanceKlass* check = find_class(d_hash, name, dictionary); 779 if (check != NULL) { 780 // Klass is already loaded, so just return it 781 k = check; 782 class_has_been_loaded = true; 783 } 784 // check if other thread failed to load and cleaned up 785 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 786 } 787 } 788 } 789 } 790 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 791 // case 4: parallelCapable: allow competing threads to try 792 // LOAD_INSTANCE in parallel 793 794 if (!throw_circularity_error && !class_has_been_loaded) { 795 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 796 load_instance_added = true; 797 // For class loaders that do not acquire the classloader object lock, 798 // if they did not catch another thread holding LOAD_INSTANCE, 799 // need a check analogous to the acquire ObjectLocker/find_class 800 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 801 // one final check if the load has already completed 802 // class loaders holding the ObjectLock shouldn't find the class here 803 InstanceKlass* check = find_class(d_hash, name, dictionary); 804 if (check != NULL) { 805 // Klass is already loaded, so return it after checking/adding protection domain 806 k = check; 807 class_has_been_loaded = true; 808 } 809 } 810 } 811 812 // must throw error outside of owning lock 813 if (throw_circularity_error) { 814 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 815 ResourceMark rm(THREAD); 816 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 817 } 818 819 if (!class_has_been_loaded) { 820 821 // Do actual loading 822 k = load_instance_class(name, class_loader, THREAD); 823 824 // If everything was OK (no exceptions, no null return value), and 825 // class_loader is NOT the defining loader, do a little more bookkeeping. 826 if (!HAS_PENDING_EXCEPTION && k != NULL && 827 !oopDesc::equals(k->class_loader(), class_loader())) { 828 829 check_constraints(d_hash, k, class_loader, false, THREAD); 830 831 // Need to check for a PENDING_EXCEPTION again; check_constraints 832 // can throw and doesn't use the CHECK macro. 833 if (!HAS_PENDING_EXCEPTION) { 834 { // Grabbing the Compile_lock prevents systemDictionary updates 835 // during compilations. 836 MutexLocker mu(Compile_lock, THREAD); 837 update_dictionary(d_hash, p_index, p_hash, 838 k, class_loader, THREAD); 839 } 840 841 if (JvmtiExport::should_post_class_load()) { 842 Thread *thread = THREAD; 843 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 844 JvmtiExport::post_class_load((JavaThread *) thread, k); 845 } 846 } 847 } 848 } // load_instance_class 849 850 if (load_instance_added == true) { 851 // clean up placeholder entries for LOAD_INSTANCE success or error 852 // This brackets the SystemDictionary updates for both defining 853 // and initiating loaders 854 MutexLocker mu(SystemDictionary_lock, THREAD); 855 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 856 SystemDictionary_lock->notify_all(); 857 } 858 } 859 860 if (HAS_PENDING_EXCEPTION || k == NULL) { 861 return NULL; 862 } 863 if (class_load_start_event.should_commit()) { 864 post_class_load_event(&class_load_start_event, k, loader_data); 865 } 866 #ifdef ASSERT 867 { 868 ClassLoaderData* loader_data = k->class_loader_data(); 869 MutexLocker mu(SystemDictionary_lock, THREAD); 870 Klass* kk = find_class(name, loader_data); 871 assert(kk == k, "should be present in dictionary"); 872 } 873 #endif 874 875 // return if the protection domain in NULL 876 if (protection_domain() == NULL) return k; 877 878 // Check the protection domain has the right access 879 if (dictionary->is_valid_protection_domain(d_hash, name, 880 protection_domain)) { 881 return k; 882 } 883 884 // Verify protection domain. If it fails an exception is thrown 885 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 886 887 return k; 888 } 889 890 891 // This routine does not lock the system dictionary. 892 // 893 // Since readers don't hold a lock, we must make sure that system 894 // dictionary entries are only removed at a safepoint (when only one 895 // thread is running), and are added to in a safe way (all links must 896 // be updated in an MT-safe manner). 897 // 898 // Callers should be aware that an entry could be added just after 899 // _dictionary->bucket(index) is read here, so the caller will not see 900 // the new entry. 901 902 Klass* SystemDictionary::find(Symbol* class_name, 903 Handle class_loader, 904 Handle protection_domain, 905 TRAPS) { 906 907 // The result of this call should be consistent with the result 908 // of the call to resolve_instance_class_or_null(). 909 // See evaluation 6790209 and 4474172 for more details. 910 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 911 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 912 913 if (loader_data == NULL) { 914 // If the ClassLoaderData has not been setup, 915 // then the class loader has no entries in the dictionary. 916 return NULL; 917 } 918 919 Dictionary* dictionary = loader_data->dictionary(); 920 unsigned int d_hash = dictionary->compute_hash(class_name); 921 return dictionary->find(d_hash, class_name, 922 protection_domain); 923 } 924 925 926 // Look for a loaded instance or array klass by name. Do not do any loading. 927 // return NULL in case of error. 928 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 929 Handle class_loader, 930 Handle protection_domain, 931 TRAPS) { 932 Klass* k = NULL; 933 assert(class_name != NULL, "class name must be non NULL"); 934 935 if (FieldType::is_array(class_name)) { 936 // The name refers to an array. Parse the name. 937 // dimension and object_key in FieldArrayInfo are assigned as a 938 // side-effect of this call 939 FieldArrayInfo fd; 940 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 941 if (t != T_OBJECT) { 942 k = Universe::typeArrayKlassObj(t); 943 } else { 944 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 945 } 946 if (k != NULL) { 947 k = k->array_klass_or_null(fd.dimension()); 948 } 949 } else { 950 k = find(class_name, class_loader, protection_domain, THREAD); 951 } 952 return k; 953 } 954 955 // Note: this method is much like resolve_from_stream, but 956 // does not publish the classes via the SystemDictionary. 957 // Handles unsafe_DefineAnonymousClass and redefineclasses 958 // RedefinedClasses do not add to the class hierarchy 959 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 960 Handle class_loader, 961 Handle protection_domain, 962 ClassFileStream* st, 963 const InstanceKlass* host_klass, 964 GrowableArray<Handle>* cp_patches, 965 TRAPS) { 966 967 EventClassLoad class_load_start_event; 968 969 ClassLoaderData* loader_data; 970 if (host_klass != NULL) { 971 // Create a new CLD for anonymous class, that uses the same class loader 972 // as the host_klass 973 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same"); 974 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader); 975 } else { 976 loader_data = ClassLoaderData::class_loader_data(class_loader()); 977 } 978 979 assert(st != NULL, "invariant"); 980 assert(st->need_verify(), "invariant"); 981 982 // Parse stream and create a klass. 983 // Note that we do this even though this klass might 984 // already be present in the SystemDictionary, otherwise we would not 985 // throw potential ClassFormatErrors. 986 987 InstanceKlass* k = KlassFactory::create_from_stream(st, 988 class_name, 989 loader_data, 990 protection_domain, 991 host_klass, 992 cp_patches, 993 CHECK_NULL); 994 995 if (host_klass != NULL && k != NULL) { 996 // Anonymous classes must update ClassLoaderData holder (was host_klass loader) 997 // so that they can be unloaded when the mirror is no longer referenced. 998 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror())); 999 1000 { 1001 MutexLocker mu_r(Compile_lock, THREAD); 1002 1003 // Add to class hierarchy, initialize vtables, and do possible 1004 // deoptimizations. 1005 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1006 1007 // But, do not add to dictionary. 1008 1009 // compiled code dependencies need to be validated anyway 1010 notice_modification(); 1011 } 1012 1013 // Rewrite and patch constant pool here. 1014 k->link_class(CHECK_NULL); 1015 if (cp_patches != NULL) { 1016 k->constants()->patch_resolved_references(cp_patches); 1017 } 1018 1019 // If it's anonymous, initialize it now, since nobody else will. 1020 k->eager_initialize(CHECK_NULL); 1021 1022 // notify jvmti 1023 if (JvmtiExport::should_post_class_load()) { 1024 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1025 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1026 } 1027 if (class_load_start_event.should_commit()) { 1028 post_class_load_event(&class_load_start_event, k, loader_data); 1029 } 1030 } 1031 assert(host_klass != NULL || NULL == cp_patches, 1032 "cp_patches only found with host_klass"); 1033 1034 return k; 1035 } 1036 1037 // Add a klass to the system from a stream (called by jni_DefineClass and 1038 // JVM_DefineClass). 1039 // Note: class_name can be NULL. In that case we do not know the name of 1040 // the class until we have parsed the stream. 1041 1042 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1043 Handle class_loader, 1044 Handle protection_domain, 1045 ClassFileStream* st, 1046 TRAPS) { 1047 1048 HandleMark hm(THREAD); 1049 1050 // Classloaders that support parallelism, e.g. bootstrap classloader, 1051 // do not acquire lock here 1052 bool DoObjectLock = true; 1053 if (is_parallelCapable(class_loader)) { 1054 DoObjectLock = false; 1055 } 1056 1057 ClassLoaderData* loader_data = register_loader(class_loader); 1058 1059 // Make sure we are synchronized on the class loader before we proceed 1060 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1061 check_loader_lock_contention(lockObject, THREAD); 1062 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1063 1064 assert(st != NULL, "invariant"); 1065 1066 // Parse the stream and create a klass. 1067 // Note that we do this even though this klass might 1068 // already be present in the SystemDictionary, otherwise we would not 1069 // throw potential ClassFormatErrors. 1070 InstanceKlass* k = NULL; 1071 1072 #if INCLUDE_CDS 1073 if (!DumpSharedSpaces) { 1074 k = SystemDictionaryShared::lookup_from_stream(class_name, 1075 class_loader, 1076 protection_domain, 1077 st, 1078 CHECK_NULL); 1079 } 1080 #endif 1081 1082 if (k == NULL) { 1083 if (st->buffer() == NULL) { 1084 return NULL; 1085 } 1086 k = KlassFactory::create_from_stream(st, 1087 class_name, 1088 loader_data, 1089 protection_domain, 1090 NULL, // host_klass 1091 NULL, // cp_patches 1092 CHECK_NULL); 1093 } 1094 1095 assert(k != NULL, "no klass created"); 1096 Symbol* h_name = k->name(); 1097 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1098 1099 // Add class just loaded 1100 // If a class loader supports parallel classloading handle parallel define requests 1101 // find_or_define_instance_class may return a different InstanceKlass 1102 if (is_parallelCapable(class_loader)) { 1103 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1104 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1105 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1106 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1107 loader_data->add_to_deallocate_list(k); 1108 k = defined_k; 1109 } 1110 } else { 1111 define_instance_class(k, THREAD); 1112 } 1113 1114 // If defining the class throws an exception register 'k' for cleanup. 1115 if (HAS_PENDING_EXCEPTION) { 1116 assert(k != NULL, "Must have an instance klass here!"); 1117 loader_data->add_to_deallocate_list(k); 1118 return NULL; 1119 } 1120 1121 // Make sure we have an entry in the SystemDictionary on success 1122 debug_only( { 1123 MutexLocker mu(SystemDictionary_lock, THREAD); 1124 1125 Klass* check = find_class(h_name, k->class_loader_data()); 1126 assert(check == k, "should be present in the dictionary"); 1127 } ); 1128 1129 return k; 1130 } 1131 1132 #if INCLUDE_CDS 1133 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1134 int number_of_entries) { 1135 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1136 "bad shared dictionary size."); 1137 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1138 _shared_dictionary_size, t, number_of_entries); 1139 } 1140 1141 1142 // If there is a shared dictionary, then find the entry for the 1143 // given shared system class, if any. 1144 1145 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1146 if (shared_dictionary() != NULL) { 1147 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1148 int d_index = shared_dictionary()->hash_to_index(d_hash); 1149 1150 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1151 } else { 1152 return NULL; 1153 } 1154 } 1155 1156 1157 // Load a class from the shared spaces (found through the shared system 1158 // dictionary). Force the superclass and all interfaces to be loaded. 1159 // Update the class definition to include sibling classes and no 1160 // subclasses (yet). [Classes in the shared space are not part of the 1161 // object hierarchy until loaded.] 1162 1163 InstanceKlass* SystemDictionary::load_shared_class( 1164 Symbol* class_name, Handle class_loader, TRAPS) { 1165 InstanceKlass* ik = find_shared_class(class_name); 1166 // Make sure we only return the boot class for the NULL classloader. 1167 if (ik != NULL && 1168 ik->is_shared_boot_class() && class_loader.is_null()) { 1169 Handle protection_domain; 1170 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1171 } 1172 return NULL; 1173 } 1174 1175 // Check if a shared class can be loaded by the specific classloader: 1176 // 1177 // NULL classloader: 1178 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1179 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1180 // be defined in an unnamed module. 1181 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1182 InstanceKlass* ik, 1183 Handle class_loader, TRAPS) { 1184 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1185 "Cannot use sharing if java.base is patched"); 1186 ResourceMark rm; 1187 int path_index = ik->shared_classpath_index(); 1188 ClassLoaderData* loader_data = class_loader_data(class_loader); 1189 if (path_index < 0) { 1190 // path_index < 0 indicates that the class is intended for a custom loader 1191 // and should not be loaded by boot/platform/app loaders 1192 if (loader_data->is_builtin_class_loader_data()) { 1193 return false; 1194 } else { 1195 return true; 1196 } 1197 } 1198 SharedClassPathEntry* ent = 1199 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); 1200 if (!Universe::is_module_initialized()) { 1201 assert(ent != NULL && ent->is_modules_image(), 1202 "Loading non-bootstrap classes before the module system is initialized"); 1203 assert(class_loader.is_null(), "sanity"); 1204 return true; 1205 } 1206 // Get the pkg_entry from the classloader 1207 TempNewSymbol pkg_name = NULL; 1208 PackageEntry* pkg_entry = NULL; 1209 ModuleEntry* mod_entry = NULL; 1210 const char* pkg_string = NULL; 1211 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1212 if (pkg_name != NULL) { 1213 pkg_string = pkg_name->as_C_string(); 1214 if (loader_data != NULL) { 1215 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1216 } 1217 if (pkg_entry != NULL) { 1218 mod_entry = pkg_entry->module(); 1219 } 1220 } 1221 1222 // If the archived class is from a module that has been patched at runtime, 1223 // the class cannot be loaded from the archive. 1224 if (mod_entry != NULL && mod_entry->is_patched()) { 1225 return false; 1226 } 1227 1228 if (class_loader.is_null()) { 1229 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1230 // The NULL classloader can load archived class originated from the 1231 // "modules" jimage and the -Xbootclasspath/a. For class from the 1232 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1233 // by the NULL classloader. 1234 if (mod_entry != NULL) { 1235 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1236 // ModuleEntry's location agrees with the archived class' origination. 1237 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1238 return true; // Module class from the "module" jimage 1239 } 1240 } 1241 1242 // If the archived class is not from the "module" jimage, the class can be 1243 // loaded by the NULL classloader if 1244 // 1245 // 1. the class is from the unamed package 1246 // 2. or, the class is not from a module defined in the NULL classloader 1247 // 3. or, the class is from an unamed module 1248 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1249 // the class is from the -Xbootclasspath/a 1250 if (pkg_string == NULL || 1251 pkg_entry == NULL || 1252 pkg_entry->in_unnamed_module()) { 1253 assert(mod_entry == NULL || 1254 mod_entry == loader_data->unnamed_module(), 1255 "the unnamed module is not defined in the classloader"); 1256 return true; 1257 } 1258 } 1259 return false; 1260 } else { 1261 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1262 ik, class_loader, pkg_string, pkg_name, 1263 pkg_entry, mod_entry, CHECK_(false)); 1264 return res; 1265 } 1266 } 1267 1268 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1269 Handle class_loader, 1270 Handle protection_domain, TRAPS) { 1271 1272 if (ik != NULL) { 1273 Symbol* class_name = ik->name(); 1274 1275 bool visible = is_shared_class_visible( 1276 class_name, ik, class_loader, CHECK_NULL); 1277 if (!visible) { 1278 return NULL; 1279 } 1280 1281 // Resolve the superclass and interfaces. They must be the same 1282 // as in dump time, because the layout of <ik> depends on 1283 // the specific layout of ik->super() and ik->local_interfaces(). 1284 // 1285 // If unexpected superclass or interfaces are found, we cannot 1286 // load <ik> from the shared archive. 1287 1288 if (ik->super() != NULL) { 1289 Symbol* cn = ik->super()->name(); 1290 Klass *s = resolve_super_or_fail(class_name, cn, 1291 class_loader, protection_domain, true, CHECK_NULL); 1292 if (s != ik->super()) { 1293 // The dynamically resolved super class is not the same as the one we used during dump time, 1294 // so we cannot use ik. 1295 return NULL; 1296 } else { 1297 assert(s->is_shared(), "must be"); 1298 } 1299 } 1300 1301 Array<Klass*>* interfaces = ik->local_interfaces(); 1302 int num_interfaces = interfaces->length(); 1303 for (int index = 0; index < num_interfaces; index++) { 1304 Klass* k = interfaces->at(index); 1305 Symbol* name = k->name(); 1306 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1307 if (k != i) { 1308 // The dynamically resolved interface class is not the same as the one we used during dump time, 1309 // so we cannot use ik. 1310 return NULL; 1311 } else { 1312 assert(i->is_shared(), "must be"); 1313 } 1314 } 1315 1316 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1317 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1318 if (new_ik != NULL) { 1319 // The class is changed by CFLH. Return the new class. The shared class is 1320 // not used. 1321 return new_ik; 1322 } 1323 1324 // Adjust methods to recover missing data. They need addresses for 1325 // interpreter entry points and their default native method address 1326 // must be reset. 1327 1328 // Updating methods must be done under a lock so multiple 1329 // threads don't update these in parallel 1330 // 1331 // Shared classes are all currently loaded by either the bootstrap or 1332 // internal parallel class loaders, so this will never cause a deadlock 1333 // on a custom class loader lock. 1334 1335 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1336 { 1337 HandleMark hm(THREAD); 1338 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1339 check_loader_lock_contention(lockObject, THREAD); 1340 ObjectLocker ol(lockObject, THREAD, true); 1341 // prohibited package check assumes all classes loaded from archive call 1342 // restore_unshareable_info which calls ik->set_package() 1343 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1344 } 1345 1346 ik->print_class_load_logging(loader_data, NULL, NULL); 1347 1348 // For boot loader, ensure that GetSystemPackage knows that a class in this 1349 // package was loaded. 1350 if (class_loader.is_null()) { 1351 int path_index = ik->shared_classpath_index(); 1352 ResourceMark rm; 1353 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1354 } 1355 1356 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1357 // Only dump the classes that can be stored into CDS archive 1358 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1359 ResourceMark rm(THREAD); 1360 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1361 classlist_file->flush(); 1362 } 1363 } 1364 1365 // notify a class loaded from shared object 1366 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1367 } 1368 1369 ik->set_has_passed_fingerprint_check(false); 1370 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1371 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1372 uint64_t cds_fp = ik->get_stored_fingerprint(); 1373 if (aot_fp != 0 && aot_fp == cds_fp) { 1374 // This class matches with a class saved in an AOT library 1375 ik->set_has_passed_fingerprint_check(true); 1376 } else { 1377 ResourceMark rm; 1378 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1379 } 1380 } 1381 return ik; 1382 } 1383 1384 void SystemDictionary::clear_invoke_method_table() { 1385 SymbolPropertyEntry* spe = NULL; 1386 for (int index = 0; index < _invoke_method_table->table_size(); index++) { 1387 SymbolPropertyEntry* p = _invoke_method_table->bucket(index); 1388 while (p != NULL) { 1389 spe = p; 1390 p = p->next(); 1391 _invoke_method_table->free_entry(spe); 1392 } 1393 } 1394 } 1395 #endif // INCLUDE_CDS 1396 1397 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1398 1399 if (class_loader.is_null()) { 1400 ResourceMark rm; 1401 PackageEntry* pkg_entry = NULL; 1402 bool search_only_bootloader_append = false; 1403 ClassLoaderData *loader_data = class_loader_data(class_loader); 1404 1405 // Find the package in the boot loader's package entry table. 1406 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1407 if (pkg_name != NULL) { 1408 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1409 } 1410 1411 // Prior to attempting to load the class, enforce the boot loader's 1412 // visibility boundaries. 1413 if (!Universe::is_module_initialized()) { 1414 // During bootstrapping, prior to module initialization, any 1415 // class attempting to be loaded must be checked against the 1416 // java.base packages in the boot loader's PackageEntryTable. 1417 // No class outside of java.base is allowed to be loaded during 1418 // this bootstrapping window. 1419 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1420 // Class is either in the unnamed package or in 1421 // a named package within the unnamed module. Either 1422 // case is outside of java.base, do not attempt to 1423 // load the class post java.base definition. If 1424 // java.base has not been defined, let the class load 1425 // and its package will be checked later by 1426 // ModuleEntryTable::verify_javabase_packages. 1427 if (ModuleEntryTable::javabase_defined()) { 1428 return NULL; 1429 } 1430 } else { 1431 // Check that the class' package is defined within java.base. 1432 ModuleEntry* mod_entry = pkg_entry->module(); 1433 Symbol* mod_entry_name = mod_entry->name(); 1434 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1435 return NULL; 1436 } 1437 } 1438 } else { 1439 // After the module system has been initialized, check if the class' 1440 // package is in a module defined to the boot loader. 1441 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1442 // Class is either in the unnamed package, in a named package 1443 // within a module not defined to the boot loader or in a 1444 // a named package within the unnamed module. In all cases, 1445 // limit visibility to search for the class only in the boot 1446 // loader's append path. 1447 search_only_bootloader_append = true; 1448 } 1449 } 1450 1451 // Prior to bootstrapping's module initialization, never load a class outside 1452 // of the boot loader's module path 1453 assert(Universe::is_module_initialized() || 1454 !search_only_bootloader_append, 1455 "Attempt to load a class outside of boot loader's module path"); 1456 1457 // Search the shared system dictionary for classes preloaded into the 1458 // shared spaces. 1459 InstanceKlass* k = NULL; 1460 { 1461 #if INCLUDE_CDS 1462 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1463 k = load_shared_class(class_name, class_loader, THREAD); 1464 #endif 1465 } 1466 1467 if (k == NULL) { 1468 // Use VM class loader 1469 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1470 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1471 } 1472 1473 // find_or_define_instance_class may return a different InstanceKlass 1474 if (k != NULL) { 1475 InstanceKlass* defined_k = 1476 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1477 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1478 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1479 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1480 loader_data->add_to_deallocate_list(k); 1481 k = defined_k; 1482 } else if (HAS_PENDING_EXCEPTION) { 1483 loader_data->add_to_deallocate_list(k); 1484 return NULL; 1485 } 1486 } 1487 return k; 1488 } else { 1489 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1490 ResourceMark rm(THREAD); 1491 1492 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1493 JavaThread* jt = (JavaThread*) THREAD; 1494 1495 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1496 ClassLoader::perf_app_classload_selftime(), 1497 ClassLoader::perf_app_classload_count(), 1498 jt->get_thread_stat()->perf_recursion_counts_addr(), 1499 jt->get_thread_stat()->perf_timers_addr(), 1500 PerfClassTraceTime::CLASS_LOAD); 1501 1502 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1503 // Translate to external class name format, i.e., convert '/' chars to '.' 1504 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1505 1506 JavaValue result(T_OBJECT); 1507 1508 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1509 1510 // Call public unsynchronized loadClass(String) directly for all class loaders. 1511 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1512 // acquire a class-name based lock rather than the class loader object lock. 1513 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1514 JavaCalls::call_virtual(&result, 1515 class_loader, 1516 spec_klass, 1517 vmSymbols::loadClass_name(), 1518 vmSymbols::string_class_signature(), 1519 string, 1520 CHECK_NULL); 1521 1522 assert(result.get_type() == T_OBJECT, "just checking"); 1523 oop obj = (oop) result.get_jobject(); 1524 1525 // Primitive classes return null since forName() can not be 1526 // used to obtain any of the Class objects representing primitives or void 1527 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1528 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1529 // For user defined Java class loaders, check that the name returned is 1530 // the same as that requested. This check is done for the bootstrap 1531 // loader when parsing the class file. 1532 if (class_name == k->name()) { 1533 return k; 1534 } 1535 } 1536 // Class is not found or has the wrong name, return NULL 1537 return NULL; 1538 } 1539 } 1540 1541 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) { 1542 EventClassDefine event; 1543 if (event.should_commit()) { 1544 event.set_definedClass(k); 1545 event.set_definingClassLoader(def_cld); 1546 event.commit(); 1547 } 1548 } 1549 1550 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1551 1552 HandleMark hm(THREAD); 1553 ClassLoaderData* loader_data = k->class_loader_data(); 1554 Handle class_loader_h(THREAD, loader_data->class_loader()); 1555 1556 // for bootstrap and other parallel classloaders don't acquire lock, 1557 // use placeholder token 1558 // If a parallelCapable class loader calls define_instance_class instead of 1559 // find_or_define_instance_class to get here, we have a timing 1560 // hole with systemDictionary updates and check_constraints 1561 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1562 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1563 compute_loader_lock_object(class_loader_h, THREAD)), 1564 "define called without lock"); 1565 } 1566 1567 // Check class-loading constraints. Throw exception if violation is detected. 1568 // Grabs and releases SystemDictionary_lock 1569 // The check_constraints/find_class call and update_dictionary sequence 1570 // must be "atomic" for a specific class/classloader pair so we never 1571 // define two different instanceKlasses for that class/classloader pair. 1572 // Existing classloaders will call define_instance_class with the 1573 // classloader lock held 1574 // Parallel classloaders will call find_or_define_instance_class 1575 // which will require a token to perform the define class 1576 Symbol* name_h = k->name(); 1577 Dictionary* dictionary = loader_data->dictionary(); 1578 unsigned int d_hash = dictionary->compute_hash(name_h); 1579 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1580 1581 // Register class just loaded with class loader (placed in Vector) 1582 // Note we do this before updating the dictionary, as this can 1583 // fail with an OutOfMemoryError (if it does, we will *not* put this 1584 // class in the dictionary and will not update the class hierarchy). 1585 // JVMTI FollowReferences needs to find the classes this way. 1586 if (k->class_loader() != NULL) { 1587 methodHandle m(THREAD, Universe::loader_addClass_method()); 1588 JavaValue result(T_VOID); 1589 JavaCallArguments args(class_loader_h); 1590 args.push_oop(Handle(THREAD, k->java_mirror())); 1591 JavaCalls::call(&result, m, &args, CHECK); 1592 } 1593 1594 // Add the new class. We need recompile lock during update of CHA. 1595 { 1596 unsigned int p_hash = placeholders()->compute_hash(name_h); 1597 int p_index = placeholders()->hash_to_index(p_hash); 1598 1599 MutexLocker mu_r(Compile_lock, THREAD); 1600 1601 // Add to class hierarchy, initialize vtables, and do possible 1602 // deoptimizations. 1603 add_to_hierarchy(k, CHECK); // No exception, but can block 1604 1605 // Add to systemDictionary - so other classes can see it. 1606 // Grabs and releases SystemDictionary_lock 1607 update_dictionary(d_hash, p_index, p_hash, 1608 k, class_loader_h, THREAD); 1609 } 1610 k->eager_initialize(THREAD); 1611 1612 // notify jvmti 1613 if (JvmtiExport::should_post_class_load()) { 1614 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1615 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1616 1617 } 1618 post_class_define_event(k, loader_data); 1619 } 1620 1621 // Support parallel classloading 1622 // All parallel class loaders, including bootstrap classloader 1623 // lock a placeholder entry for this class/class_loader pair 1624 // to allow parallel defines of different classes for this class loader 1625 // With AllowParallelDefine flag==true, in case they do not synchronize around 1626 // FindLoadedClass/DefineClass, calls, we check for parallel 1627 // loading for them, wait if a defineClass is in progress 1628 // and return the initial requestor's results 1629 // This flag does not apply to the bootstrap classloader. 1630 // With AllowParallelDefine flag==false, call through to define_instance_class 1631 // which will throw LinkageError: duplicate class definition. 1632 // False is the requested default. 1633 // For better performance, the class loaders should synchronize 1634 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1635 // potentially waste time reading and parsing the bytestream. 1636 // Note: VM callers should ensure consistency of k/class_name,class_loader 1637 // Be careful when modifying this code: once you have run 1638 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1639 // you need to find_and_remove it before returning. 1640 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1641 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1642 InstanceKlass* k, TRAPS) { 1643 1644 Symbol* name_h = k->name(); // passed in class_name may be null 1645 ClassLoaderData* loader_data = class_loader_data(class_loader); 1646 Dictionary* dictionary = loader_data->dictionary(); 1647 1648 unsigned int d_hash = dictionary->compute_hash(name_h); 1649 1650 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1651 unsigned int p_hash = placeholders()->compute_hash(name_h); 1652 int p_index = placeholders()->hash_to_index(p_hash); 1653 PlaceholderEntry* probe; 1654 1655 { 1656 MutexLocker mu(SystemDictionary_lock, THREAD); 1657 // First check if class already defined 1658 if (is_parallelDefine(class_loader)) { 1659 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1660 if (check != NULL) { 1661 return check; 1662 } 1663 } 1664 1665 // Acquire define token for this class/classloader 1666 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1667 // Wait if another thread defining in parallel 1668 // All threads wait - even those that will throw duplicate class: otherwise 1669 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1670 // if other thread has not finished updating dictionary 1671 while (probe->definer() != NULL) { 1672 SystemDictionary_lock->wait(); 1673 } 1674 // Only special cases allow parallel defines and can use other thread's results 1675 // Other cases fall through, and may run into duplicate defines 1676 // caught by finding an entry in the SystemDictionary 1677 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1678 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1679 SystemDictionary_lock->notify_all(); 1680 #ifdef ASSERT 1681 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1682 assert(check != NULL, "definer missed recording success"); 1683 #endif 1684 return probe->instance_klass(); 1685 } else { 1686 // This thread will define the class (even if earlier thread tried and had an error) 1687 probe->set_definer(THREAD); 1688 } 1689 } 1690 1691 define_instance_class(k, THREAD); 1692 1693 Handle linkage_exception = Handle(); // null handle 1694 1695 // definer must notify any waiting threads 1696 { 1697 MutexLocker mu(SystemDictionary_lock, THREAD); 1698 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1699 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1700 if (probe != NULL) { 1701 if (HAS_PENDING_EXCEPTION) { 1702 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1703 CLEAR_PENDING_EXCEPTION; 1704 } else { 1705 probe->set_instance_klass(k); 1706 } 1707 probe->set_definer(NULL); 1708 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1709 SystemDictionary_lock->notify_all(); 1710 } 1711 } 1712 1713 // Can't throw exception while holding lock due to rank ordering 1714 if (linkage_exception() != NULL) { 1715 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1716 } 1717 1718 return k; 1719 } 1720 1721 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1722 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1723 if (class_loader.is_null()) { 1724 return Handle(THREAD, _system_loader_lock_obj); 1725 } else { 1726 return class_loader; 1727 } 1728 } 1729 1730 // This method is added to check how often we have to wait to grab loader 1731 // lock. The results are being recorded in the performance counters defined in 1732 // ClassLoader::_sync_systemLoaderLockContentionRate and 1733 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1734 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1735 if (!UsePerfData) { 1736 return; 1737 } 1738 1739 assert(!loader_lock.is_null(), "NULL lock object"); 1740 1741 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1742 == ObjectSynchronizer::owner_other) { 1743 // contention will likely happen, so increment the corresponding 1744 // contention counter. 1745 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) { 1746 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1747 } else { 1748 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1749 } 1750 } 1751 } 1752 1753 // ---------------------------------------------------------------------------- 1754 // Lookup 1755 1756 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1757 Symbol* class_name, 1758 Dictionary* dictionary) { 1759 assert_locked_or_safepoint(SystemDictionary_lock); 1760 int index = dictionary->hash_to_index(hash); 1761 return dictionary->find_class(index, hash, class_name); 1762 } 1763 1764 1765 // Basic find on classes in the midst of being loaded 1766 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1767 ClassLoaderData* loader_data) { 1768 assert_locked_or_safepoint(SystemDictionary_lock); 1769 unsigned int p_hash = placeholders()->compute_hash(class_name); 1770 int p_index = placeholders()->hash_to_index(p_hash); 1771 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1772 } 1773 1774 1775 // Used for assertions and verification only 1776 // Precalculating the hash and index is an optimization because there are many lookups 1777 // before adding the class. 1778 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1779 assert_locked_or_safepoint(SystemDictionary_lock); 1780 #ifndef ASSERT 1781 guarantee(VerifyBeforeGC || 1782 VerifyDuringGC || 1783 VerifyBeforeExit || 1784 VerifyDuringStartup || 1785 VerifyAfterGC, "too expensive"); 1786 #endif 1787 1788 Dictionary* dictionary = loader_data->dictionary(); 1789 unsigned int d_hash = dictionary->compute_hash(class_name); 1790 return find_class(d_hash, class_name, dictionary); 1791 } 1792 1793 1794 // ---------------------------------------------------------------------------- 1795 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1796 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1797 // before a new class is used. 1798 1799 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1800 assert(k != NULL, "just checking"); 1801 assert_locked_or_safepoint(Compile_lock); 1802 1803 // Link into hierachy. Make sure the vtables are initialized before linking into 1804 k->append_to_sibling_list(); // add to superklass/sibling list 1805 k->process_interfaces(THREAD); // handle all "implements" declarations 1806 k->set_init_state(InstanceKlass::loaded); 1807 // Now flush all code that depended on old class hierarchy. 1808 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1809 // Also, first reinitialize vtable because it may have gotten out of synch 1810 // while the new class wasn't connected to the class hierarchy. 1811 CodeCache::flush_dependents_on(k); 1812 } 1813 1814 // ---------------------------------------------------------------------------- 1815 // GC support 1816 1817 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1818 // Note: anonymous classes are not in the SD. 1819 bool SystemDictionary::do_unloading(GCTimer* gc_timer, 1820 bool do_cleaning) { 1821 1822 bool unloading_occurred; 1823 { 1824 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1825 1826 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1827 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning); 1828 } 1829 1830 if (unloading_occurred) { 1831 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1832 constraints()->purge_loader_constraints(); 1833 resolution_errors()->purge_resolution_errors(); 1834 } 1835 1836 { 1837 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1838 // Oops referenced by the protection domain cache table may get unreachable independently 1839 // of the class loader (eg. cached protection domain oops). So we need to 1840 // explicitly unlink them here. 1841 _pd_cache_table->unlink(); 1842 } 1843 1844 if (do_cleaning) { 1845 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1846 ResolvedMethodTable::unlink(); 1847 } 1848 1849 return unloading_occurred; 1850 } 1851 1852 void SystemDictionary::oops_do(OopClosure* f) { 1853 f->do_oop(&_java_system_loader); 1854 f->do_oop(&_java_platform_loader); 1855 f->do_oop(&_system_loader_lock_obj); 1856 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1857 1858 // Visit extra methods 1859 invoke_method_table()->oops_do(f); 1860 } 1861 1862 // CDS: scan and relocate all classes in the system dictionary. 1863 void SystemDictionary::classes_do(MetaspaceClosure* it) { 1864 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); 1865 } 1866 1867 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1868 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1869 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1870 it->push(well_known_klass_addr((WKID)id)); 1871 } 1872 } 1873 1874 void SystemDictionary::methods_do(void f(Method*)) { 1875 // Walk methods in loaded classes 1876 ClassLoaderDataGraph::methods_do(f); 1877 // Walk method handle intrinsics 1878 invoke_method_table()->methods_do(f); 1879 } 1880 1881 class RemoveClassesClosure : public CLDClosure { 1882 public: 1883 void do_cld(ClassLoaderData* cld) { 1884 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 1885 cld->dictionary()->remove_classes_in_error_state(); 1886 } 1887 } 1888 }; 1889 1890 void SystemDictionary::remove_classes_in_error_state() { 1891 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 1892 RemoveClassesClosure rcc; 1893 ClassLoaderDataGraph::cld_do(&rcc); 1894 } 1895 1896 // ---------------------------------------------------------------------------- 1897 // Initialization 1898 1899 void SystemDictionary::initialize(TRAPS) { 1900 // Allocate arrays 1901 _placeholders = new PlaceholderTable(_placeholder_table_size); 1902 _number_of_modifications = 0; 1903 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1904 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1905 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1906 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 1907 1908 // Allocate private object used as system class loader lock 1909 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1910 // Initialize basic classes 1911 initialize_preloaded_classes(CHECK); 1912 } 1913 1914 // Compact table of directions on the initialization of klasses: 1915 static const short wk_init_info[] = { 1916 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1917 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1918 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1919 | (int)SystemDictionary::option ), 1920 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1921 #undef WK_KLASS_INIT_INFO 1922 0 1923 }; 1924 1925 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 1926 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1927 int info = wk_init_info[id - FIRST_WKID]; 1928 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1929 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1930 InstanceKlass** klassp = &_well_known_klasses[id]; 1931 1932 bool must_load; 1933 #if INCLUDE_JVMCI 1934 if (EnableJVMCI) { 1935 // If JVMCI is enabled we require its classes to be found. 1936 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 1937 } else 1938 #endif 1939 { 1940 must_load = (init_opt < SystemDictionary::Opt); 1941 } 1942 1943 if ((*klassp) == NULL) { 1944 Klass* k; 1945 if (must_load) { 1946 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 1947 } else { 1948 k = resolve_or_null(symbol, CHECK_0); // load optional klass 1949 } 1950 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 1951 } 1952 return ((*klassp) != NULL); 1953 } 1954 1955 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1956 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1957 for (int id = (int)start_id; id < (int)limit_id; id++) { 1958 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1959 int info = wk_init_info[id - FIRST_WKID]; 1960 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1961 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1962 1963 initialize_wk_klass((WKID)id, opt, CHECK); 1964 } 1965 1966 // move the starting value forward to the limit: 1967 start_id = limit_id; 1968 } 1969 1970 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1971 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 1972 1973 // Create the ModuleEntry for java.base. This call needs to be done here, 1974 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 1975 ClassLoader::classLoader_init2(CHECK); 1976 1977 // Preload commonly used klasses 1978 WKID scan = FIRST_WKID; 1979 // first do Object, then String, Class 1980 #if INCLUDE_CDS 1981 if (UseSharedSpaces) { 1982 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1983 // Initialize the constant pool for the Object_class 1984 Object_klass()->constants()->restore_unshareable_info(CHECK); 1985 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1986 } else 1987 #endif 1988 { 1989 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1990 } 1991 1992 // Calculate offsets for String and Class classes since they are loaded and 1993 // can be used after this point. 1994 java_lang_String::compute_offsets(); 1995 java_lang_Class::compute_offsets(); 1996 1997 // Fixup mirrors for classes loaded before java.lang.Class. 1998 // These calls iterate over the objects currently in the perm gen 1999 // so calling them at this point is matters (not before when there 2000 // are fewer objects and not later after there are more objects 2001 // in the perm gen. 2002 Universe::initialize_basic_type_mirrors(CHECK); 2003 Universe::fixup_mirrors(CHECK); 2004 2005 // do a bunch more: 2006 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2007 2008 // Preload ref klasses and set reference types 2009 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2010 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2011 2012 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2013 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2014 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2015 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2016 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2017 2018 // JSR 292 classes 2019 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2020 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2021 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 2022 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 2023 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); 2024 2025 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2026 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2027 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2028 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2029 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2030 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2031 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2032 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2033 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2034 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2035 2036 { // Compute whether we should use checkPackageAccess or NOT 2037 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2038 _has_checkPackageAccess = (method != NULL); 2039 } 2040 } 2041 2042 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2043 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2044 BasicType SystemDictionary::box_klass_type(Klass* k) { 2045 assert(k != NULL, ""); 2046 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2047 if (_box_klasses[i] == k) 2048 return (BasicType)i; 2049 } 2050 return T_OBJECT; 2051 } 2052 2053 // Constraints on class loaders. The details of the algorithm can be 2054 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2055 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2056 // that the dictionary needs to maintain a set of contraints that 2057 // must be satisfied by all classes in the dictionary. 2058 // if defining is true, then LinkageError if already in dictionary 2059 // if initiating loader, then ok if InstanceKlass matches existing entry 2060 2061 void SystemDictionary::check_constraints(unsigned int d_hash, 2062 InstanceKlass* k, 2063 Handle class_loader, 2064 bool defining, 2065 TRAPS) { 2066 ResourceMark rm(THREAD); 2067 stringStream ss; 2068 bool throwException = false; 2069 2070 { 2071 Symbol *name = k->name(); 2072 ClassLoaderData *loader_data = class_loader_data(class_loader); 2073 2074 MutexLocker mu(SystemDictionary_lock, THREAD); 2075 2076 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2077 if (check != NULL) { 2078 // If different InstanceKlass - duplicate class definition, 2079 // else - ok, class loaded by a different thread in parallel. 2080 // We should only have found it if it was done loading and ok to use. 2081 // The dictionary only holds instance classes, placeholders 2082 // also hold array classes. 2083 2084 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2085 if ((defining == true) || (k != check)) { 2086 throwException = true; 2087 ss.print("loader %s", loader_data->loader_name_and_id()); 2088 ss.print(" attempted duplicate %s definition for %s. (%s)", 2089 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false,true)); 2090 } else { 2091 return; 2092 } 2093 } 2094 2095 #ifdef ASSERT 2096 Symbol* ph_check = find_placeholder(name, loader_data); 2097 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2098 #endif 2099 2100 if (throwException == false) { 2101 if (constraints()->check_or_update(k, class_loader, name) == false) { 2102 throwException = true; 2103 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id()); 2104 ss.print(" wants to load %s %s.", 2105 k->external_kind(), k->external_name()); 2106 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); 2107 if (existing_klass->class_loader() != class_loader()) { 2108 ss.print(" A different %s with the same name was previously loaded by %s. (%s)", 2109 existing_klass->external_kind(), 2110 existing_klass->class_loader_data()->loader_name_and_id(), 2111 existing_klass->class_in_module_of_loader(false,true)); 2112 } else { 2113 ss.print(" (%s)", k->class_in_module_of_loader(false,true)); 2114 } 2115 } 2116 } 2117 } 2118 2119 // Throw error now if needed (cannot throw while holding 2120 // SystemDictionary_lock because of rank ordering) 2121 if (throwException == true) { 2122 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); 2123 } 2124 } 2125 2126 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2127 // have been called. 2128 void SystemDictionary::update_dictionary(unsigned int d_hash, 2129 int p_index, unsigned int p_hash, 2130 InstanceKlass* k, 2131 Handle class_loader, 2132 TRAPS) { 2133 // Compile_lock prevents systemDictionary updates during compilations 2134 assert_locked_or_safepoint(Compile_lock); 2135 Symbol* name = k->name(); 2136 ClassLoaderData *loader_data = class_loader_data(class_loader); 2137 2138 { 2139 MutexLocker mu1(SystemDictionary_lock, THREAD); 2140 2141 // See whether biased locking is enabled and if so set it for this 2142 // klass. 2143 // Note that this must be done past the last potential blocking 2144 // point / safepoint. We enable biased locking lazily using a 2145 // VM_Operation to iterate the SystemDictionary and installing the 2146 // biasable mark word into each InstanceKlass's prototype header. 2147 // To avoid race conditions where we accidentally miss enabling the 2148 // optimization for one class in the process of being added to the 2149 // dictionary, we must not safepoint after the test of 2150 // BiasedLocking::enabled(). 2151 if (UseBiasedLocking && BiasedLocking::enabled()) { 2152 // Set biased locking bit for all loaded classes; it will be 2153 // cleared if revocation occurs too often for this type 2154 // NOTE that we must only do this when the class is initally 2155 // defined, not each time it is referenced from a new class loader 2156 if (oopDesc::equals(k->class_loader(), class_loader())) { 2157 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2158 } 2159 } 2160 2161 // Make a new dictionary entry. 2162 Dictionary* dictionary = loader_data->dictionary(); 2163 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2164 if (sd_check == NULL) { 2165 dictionary->add_klass(d_hash, name, k); 2166 notice_modification(); 2167 } 2168 #ifdef ASSERT 2169 sd_check = find_class(d_hash, name, dictionary); 2170 assert (sd_check != NULL, "should have entry in dictionary"); 2171 // Note: there may be a placeholder entry: for circularity testing 2172 // or for parallel defines 2173 #endif 2174 SystemDictionary_lock->notify_all(); 2175 } 2176 } 2177 2178 2179 // Try to find a class name using the loader constraints. The 2180 // loader constraints might know about a class that isn't fully loaded 2181 // yet and these will be ignored. 2182 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2183 Symbol* class_name, Handle class_loader, TRAPS) { 2184 2185 // First see if it has been loaded directly. 2186 // Force the protection domain to be null. (This removes protection checks.) 2187 Handle no_protection_domain; 2188 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2189 no_protection_domain, CHECK_NULL); 2190 if (klass != NULL) 2191 return klass; 2192 2193 // Now look to see if it has been loaded elsewhere, and is subject to 2194 // a loader constraint that would require this loader to return the 2195 // klass that is already loaded. 2196 if (FieldType::is_array(class_name)) { 2197 // For array classes, their Klass*s are not kept in the 2198 // constraint table. The element Klass*s are. 2199 FieldArrayInfo fd; 2200 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2201 if (t != T_OBJECT) { 2202 klass = Universe::typeArrayKlassObj(t); 2203 } else { 2204 MutexLocker mu(SystemDictionary_lock, THREAD); 2205 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2206 } 2207 // If element class already loaded, allocate array klass 2208 if (klass != NULL) { 2209 klass = klass->array_klass_or_null(fd.dimension()); 2210 } 2211 } else { 2212 MutexLocker mu(SystemDictionary_lock, THREAD); 2213 // Non-array classes are easy: simply check the constraint table. 2214 klass = constraints()->find_constrained_klass(class_name, class_loader); 2215 } 2216 2217 return klass; 2218 } 2219 2220 2221 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2222 Handle class_loader1, 2223 Handle class_loader2, 2224 Thread* THREAD) { 2225 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2226 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2227 2228 Symbol* constraint_name = NULL; 2229 if (!FieldType::is_array(class_name)) { 2230 constraint_name = class_name; 2231 } else { 2232 // For array classes, their Klass*s are not kept in the 2233 // constraint table. The element classes are. 2234 FieldArrayInfo fd; 2235 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2236 // primitive types always pass 2237 if (t != T_OBJECT) { 2238 return true; 2239 } else { 2240 constraint_name = fd.object_key(); 2241 } 2242 } 2243 2244 Dictionary* dictionary1 = loader_data1->dictionary(); 2245 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2246 2247 Dictionary* dictionary2 = loader_data2->dictionary(); 2248 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2249 2250 { 2251 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2252 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2253 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2254 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2255 klass2, class_loader2); 2256 } 2257 } 2258 2259 // Add entry to resolution error table to record the error when the first 2260 // attempt to resolve a reference to a class has failed. 2261 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2262 Symbol* error, Symbol* message) { 2263 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2264 int index = resolution_errors()->hash_to_index(hash); 2265 { 2266 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2267 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2268 } 2269 } 2270 2271 // Delete a resolution error for RedefineClasses for a constant pool is going away 2272 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2273 resolution_errors()->delete_entry(pool); 2274 } 2275 2276 // Lookup resolution error table. Returns error if found, otherwise NULL. 2277 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2278 Symbol** message) { 2279 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2280 int index = resolution_errors()->hash_to_index(hash); 2281 { 2282 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2283 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2284 if (entry != NULL) { 2285 *message = entry->message(); 2286 return entry->error(); 2287 } else { 2288 return NULL; 2289 } 2290 } 2291 } 2292 2293 2294 // Signature constraints ensure that callers and callees agree about 2295 // the meaning of type names in their signatures. This routine is the 2296 // intake for constraints. It collects them from several places: 2297 // 2298 // * LinkResolver::resolve_method (if check_access is true) requires 2299 // that the resolving class (the caller) and the defining class of 2300 // the resolved method (the callee) agree on each type in the 2301 // method's signature. 2302 // 2303 // * LinkResolver::resolve_interface_method performs exactly the same 2304 // checks. 2305 // 2306 // * LinkResolver::resolve_field requires that the constant pool 2307 // attempting to link to a field agree with the field's defining 2308 // class about the type of the field signature. 2309 // 2310 // * klassVtable::initialize_vtable requires that, when a class 2311 // overrides a vtable entry allocated by a superclass, that the 2312 // overriding method (i.e., the callee) agree with the superclass 2313 // on each type in the method's signature. 2314 // 2315 // * klassItable::initialize_itable requires that, when a class fills 2316 // in its itables, for each non-abstract method installed in an 2317 // itable, the method (i.e., the callee) agree with the interface 2318 // on each type in the method's signature. 2319 // 2320 // All those methods have a boolean (check_access, checkconstraints) 2321 // which turns off the checks. This is used from specialized contexts 2322 // such as bootstrapping, dumping, and debugging. 2323 // 2324 // No direct constraint is placed between the class and its 2325 // supertypes. Constraints are only placed along linked relations 2326 // between callers and callees. When a method overrides or implements 2327 // an abstract method in a supertype (superclass or interface), the 2328 // constraints are placed as if the supertype were the caller to the 2329 // overriding method. (This works well, since callers to the 2330 // supertype have already established agreement between themselves and 2331 // the supertype.) As a result of all this, a class can disagree with 2332 // its supertype about the meaning of a type name, as long as that 2333 // class neither calls a relevant method of the supertype, nor is 2334 // called (perhaps via an override) from the supertype. 2335 // 2336 // 2337 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2338 // 2339 // Make sure all class components (including arrays) in the given 2340 // signature will be resolved to the same class in both loaders. 2341 // Returns the name of the type that failed a loader constraint check, or 2342 // NULL if no constraint failed. No exception except OOME is thrown. 2343 // Arrays are not added to the loader constraint table, their elements are. 2344 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2345 Handle loader1, Handle loader2, 2346 bool is_method, TRAPS) { 2347 // Nothing to do if loaders are the same. 2348 if (oopDesc::equals(loader1(), loader2())) { 2349 return NULL; 2350 } 2351 2352 SignatureStream sig_strm(signature, is_method); 2353 while (!sig_strm.is_done()) { 2354 if (sig_strm.is_object()) { 2355 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2356 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2357 return sig; 2358 } 2359 } 2360 sig_strm.next(); 2361 } 2362 return NULL; 2363 } 2364 2365 2366 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2367 Symbol* signature, 2368 TRAPS) { 2369 methodHandle empty; 2370 assert(MethodHandles::is_signature_polymorphic(iid) && 2371 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2372 iid != vmIntrinsics::_invokeGeneric, 2373 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2374 2375 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2376 int index = invoke_method_table()->hash_to_index(hash); 2377 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2378 methodHandle m; 2379 if (spe == NULL || spe->method() == NULL) { 2380 spe = NULL; 2381 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2382 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2383 if (!Arguments::is_interpreter_only()) { 2384 // Generate a compiled form of the MH intrinsic. 2385 AdapterHandlerLibrary::create_native_wrapper(m); 2386 // Check if have the compiled code. 2387 if (!m->has_compiled_code()) { 2388 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2389 "Out of space in CodeCache for method handle intrinsic", empty); 2390 } 2391 } 2392 // Now grab the lock. We might have to throw away the new method, 2393 // if a racing thread has managed to install one at the same time. 2394 { 2395 MutexLocker ml(SystemDictionary_lock, THREAD); 2396 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2397 if (spe == NULL) 2398 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2399 if (spe->method() == NULL) 2400 spe->set_method(m()); 2401 } 2402 } 2403 2404 assert(spe != NULL && spe->method() != NULL, ""); 2405 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2406 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2407 "MH intrinsic invariant"); 2408 return spe->method(); 2409 } 2410 2411 // Helper for unpacking the return value from linkMethod and linkCallSite. 2412 static methodHandle unpack_method_and_appendix(Handle mname, 2413 Klass* accessing_klass, 2414 objArrayHandle appendix_box, 2415 Handle* appendix_result, 2416 TRAPS) { 2417 methodHandle empty; 2418 if (mname.not_null()) { 2419 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2420 if (m != NULL) { 2421 oop appendix = appendix_box->obj_at(0); 2422 if (TraceMethodHandles) { 2423 #ifndef PRODUCT 2424 ttyLocker ttyl; 2425 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2426 m->print(); 2427 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2428 tty->cr(); 2429 #endif //PRODUCT 2430 } 2431 (*appendix_result) = Handle(THREAD, appendix); 2432 // the target is stored in the cpCache and if a reference to this 2433 // MemberName is dropped we need a way to make sure the 2434 // class_loader containing this method is kept alive. 2435 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2436 this_key->record_dependency(m->method_holder()); 2437 return methodHandle(THREAD, m); 2438 } 2439 } 2440 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2441 return empty; 2442 } 2443 2444 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2445 Symbol* name, 2446 Symbol* signature, 2447 Klass* accessing_klass, 2448 Handle *appendix_result, 2449 Handle *method_type_result, 2450 TRAPS) { 2451 methodHandle empty; 2452 assert(THREAD->can_call_java() ,""); 2453 Handle method_type = 2454 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2455 2456 int ref_kind = JVM_REF_invokeVirtual; 2457 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2458 Handle name_str (THREAD, name_oop); 2459 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2460 assert(appendix_box->obj_at(0) == NULL, ""); 2461 2462 // This should not happen. JDK code should take care of that. 2463 if (accessing_klass == NULL || method_type.is_null()) { 2464 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2465 } 2466 2467 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2468 JavaCallArguments args; 2469 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2470 args.push_int(ref_kind); 2471 args.push_oop(Handle(THREAD, klass->java_mirror())); 2472 args.push_oop(name_str); 2473 args.push_oop(method_type); 2474 args.push_oop(appendix_box); 2475 JavaValue result(T_OBJECT); 2476 JavaCalls::call_static(&result, 2477 SystemDictionary::MethodHandleNatives_klass(), 2478 vmSymbols::linkMethod_name(), 2479 vmSymbols::linkMethod_signature(), 2480 &args, CHECK_(empty)); 2481 Handle mname(THREAD, (oop) result.get_jobject()); 2482 (*method_type_result) = method_type; 2483 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2484 } 2485 2486 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2487 // We must ensure that all class loaders everywhere will reach this class, for any client. 2488 // This is a safe bet for public classes in java.lang, such as Object and String. 2489 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2490 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2491 static bool is_always_visible_class(oop mirror) { 2492 Klass* klass = java_lang_Class::as_Klass(mirror); 2493 if (klass->is_objArray_klass()) { 2494 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2495 } 2496 if (klass->is_typeArray_klass()) { 2497 return true; // primitive array 2498 } 2499 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2500 return klass->is_public() && 2501 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2502 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2503 } 2504 2505 2506 // Return the Java mirror (java.lang.Class instance) for a single-character 2507 // descriptor. This result, when available, is the same as produced by the 2508 // heavier API point of the same name that takes a Symbol. 2509 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2510 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2511 } 2512 2513 // Find or construct the Java mirror (java.lang.Class instance) for a 2514 // for the given field type signature, as interpreted relative to the 2515 // given class loader. Handles primitives, void, references, arrays, 2516 // and all other reflectable types, except method types. 2517 // N.B. Code in reflection should use this entry point. 2518 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2519 Klass* accessing_klass, 2520 Handle class_loader, 2521 Handle protection_domain, 2522 SignatureStream::FailureMode failure_mode, 2523 TRAPS) { 2524 Handle empty; 2525 2526 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2527 "one or the other, or perhaps neither"); 2528 2529 Symbol* type = signature; 2530 2531 // What we have here must be a valid field descriptor, 2532 // and all valid field descriptors are supported. 2533 // Produce the same java.lang.Class that reflection reports. 2534 if (type->utf8_length() == 1) { 2535 2536 // It's a primitive. (Void has a primitive mirror too.) 2537 char ch = (char) type->byte_at(0); 2538 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2539 return Handle(THREAD, find_java_mirror_for_type(ch)); 2540 2541 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2542 2543 // It's a reference type. 2544 if (accessing_klass != NULL) { 2545 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2546 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2547 } 2548 Klass* constant_type_klass; 2549 if (failure_mode == SignatureStream::ReturnNull) { 2550 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2551 CHECK_(empty)); 2552 } else { 2553 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2554 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2555 throw_error, CHECK_(empty)); 2556 } 2557 if (constant_type_klass == NULL) { 2558 return Handle(); // report failure this way 2559 } 2560 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2561 2562 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2563 if (accessing_klass != NULL) { 2564 Klass* sel_klass = constant_type_klass; 2565 bool fold_type_to_class = true; 2566 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2567 fold_type_to_class, CHECK_(empty)); 2568 } 2569 2570 return mirror; 2571 2572 } 2573 2574 // Fall through to an error. 2575 assert(false, "unsupported mirror syntax"); 2576 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2577 } 2578 2579 2580 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2581 // signature, as interpreted relative to the given class loader. 2582 // Because of class loader constraints, all method handle usage must be 2583 // consistent with this loader. 2584 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2585 Klass* accessing_klass, 2586 TRAPS) { 2587 Handle empty; 2588 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2589 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2590 int index = invoke_method_table()->hash_to_index(hash); 2591 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2592 if (spe != NULL && spe->method_type() != NULL) { 2593 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2594 return Handle(THREAD, spe->method_type()); 2595 } else if (!THREAD->can_call_java()) { 2596 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2597 return Handle(); // do not attempt from within compiler, unless it was cached 2598 } 2599 2600 Handle class_loader, protection_domain; 2601 if (accessing_klass != NULL) { 2602 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2603 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2604 } 2605 bool can_be_cached = true; 2606 int npts = ArgumentCount(signature).size(); 2607 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2608 int arg = 0; 2609 Handle rt; // the return type from the signature 2610 ResourceMark rm(THREAD); 2611 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2612 oop mirror = NULL; 2613 if (can_be_cached) { 2614 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2615 mirror = ss.as_java_mirror(Handle(), Handle(), 2616 SignatureStream::ReturnNull, CHECK_(empty)); 2617 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2618 // Fall back to accessing_klass context. 2619 can_be_cached = false; 2620 } 2621 } 2622 if (!can_be_cached) { 2623 // Resolve, throwing a real error if it doesn't work. 2624 mirror = ss.as_java_mirror(class_loader, protection_domain, 2625 SignatureStream::NCDFError, CHECK_(empty)); 2626 } 2627 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string()); 2628 if (ss.at_return_type()) 2629 rt = Handle(THREAD, mirror); 2630 else 2631 pts->obj_at_put(arg++, mirror); 2632 2633 // Check accessibility. 2634 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2635 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2636 mirror = NULL; // safety 2637 // Emulate ConstantPool::verify_constant_pool_resolve. 2638 bool fold_type_to_class = true; 2639 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2640 fold_type_to_class, CHECK_(empty)); 2641 } 2642 } 2643 assert(arg == npts, ""); 2644 2645 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2646 JavaCallArguments args(Handle(THREAD, rt())); 2647 args.push_oop(pts); 2648 JavaValue result(T_OBJECT); 2649 JavaCalls::call_static(&result, 2650 SystemDictionary::MethodHandleNatives_klass(), 2651 vmSymbols::findMethodHandleType_name(), 2652 vmSymbols::findMethodHandleType_signature(), 2653 &args, CHECK_(empty)); 2654 Handle method_type(THREAD, (oop) result.get_jobject()); 2655 2656 if (can_be_cached) { 2657 // We can cache this MethodType inside the JVM. 2658 MutexLocker ml(SystemDictionary_lock, THREAD); 2659 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2660 if (spe == NULL) 2661 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2662 if (spe->method_type() == NULL) { 2663 spe->set_method_type(method_type()); 2664 } 2665 } 2666 2667 // report back to the caller with the MethodType 2668 return method_type; 2669 } 2670 2671 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2672 Klass* accessing_klass, 2673 TRAPS) { 2674 Handle empty; 2675 ResourceMark rm(THREAD); 2676 SignatureStream ss(signature, /*is_method=*/ false); 2677 if (!ss.is_done()) { 2678 Handle class_loader, protection_domain; 2679 if (accessing_klass != NULL) { 2680 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2681 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2682 } 2683 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2684 ss.next(); 2685 if (ss.is_done()) { 2686 return Handle(THREAD, mirror); 2687 } 2688 } 2689 return empty; 2690 } 2691 2692 // Ask Java code to find or construct a method handle constant. 2693 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2694 int ref_kind, //e.g., JVM_REF_invokeVirtual 2695 Klass* callee, 2696 Symbol* name, 2697 Symbol* signature, 2698 TRAPS) { 2699 Handle empty; 2700 if (caller == NULL) { 2701 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2702 } 2703 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2704 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2705 2706 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2707 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2708 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2709 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2710 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2711 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2712 2713 if (ref_kind == JVM_REF_invokeVirtual && 2714 MethodHandles::is_signature_polymorphic_public_name(callee, name)) { 2715 // Skip resolution for public signature polymorphic methods such as 2716 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle 2717 // They require appendix argument which MemberName resolution doesn't handle. 2718 // There's special logic on JDK side to handle them 2719 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2720 } else { 2721 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); 2722 } 2723 2724 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2725 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2726 2727 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2728 JavaCallArguments args; 2729 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2730 args.push_int(ref_kind); 2731 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2732 args.push_oop(name_str); 2733 args.push_oop(type); 2734 JavaValue result(T_OBJECT); 2735 JavaCalls::call_static(&result, 2736 SystemDictionary::MethodHandleNatives_klass(), 2737 vmSymbols::linkMethodHandleConstant_name(), 2738 vmSymbols::linkMethodHandleConstant_signature(), 2739 &args, CHECK_(empty)); 2740 return Handle(THREAD, (oop) result.get_jobject()); 2741 } 2742 2743 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry 2744 Handle SystemDictionary::link_dynamic_constant(Klass* caller, 2745 int condy_index, 2746 Handle bootstrap_specifier, 2747 Symbol* name, 2748 Symbol* type, 2749 TRAPS) { 2750 Handle empty; 2751 Handle bsm, info; 2752 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2753 bsm = bootstrap_specifier; 2754 } else { 2755 assert(bootstrap_specifier->is_objArray(), ""); 2756 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2757 assert(args->length() == 2, ""); 2758 bsm = Handle(THREAD, args->obj_at(0)); 2759 info = Handle(THREAD, args->obj_at(1)); 2760 } 2761 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2762 "caller must supply a valid BSM"); 2763 2764 // This should not happen. JDK code should take care of that. 2765 if (caller == NULL) { 2766 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); 2767 } 2768 2769 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2770 2771 // Resolve the constant type in the context of the caller class 2772 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, 2773 CHECK_(empty)); 2774 2775 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) 2776 JavaCallArguments args; 2777 args.push_oop(Handle(THREAD, caller->java_mirror())); 2778 args.push_int(condy_index); 2779 args.push_oop(bsm); 2780 args.push_oop(constant_name); 2781 args.push_oop(type_mirror); 2782 args.push_oop(info); 2783 JavaValue result(T_OBJECT); 2784 JavaCalls::call_static(&result, 2785 SystemDictionary::MethodHandleNatives_klass(), 2786 vmSymbols::linkDynamicConstant_name(), 2787 vmSymbols::linkDynamicConstant_signature(), 2788 &args, CHECK_(empty)); 2789 2790 return Handle(THREAD, (oop) result.get_jobject()); 2791 } 2792 2793 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2794 // name and signature, as interpreted relative to the given class loader. 2795 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2796 int indy_index, 2797 Handle bootstrap_specifier, 2798 Symbol* name, 2799 Symbol* type, 2800 Handle *appendix_result, 2801 Handle *method_type_result, 2802 TRAPS) { 2803 methodHandle empty; 2804 Handle bsm, info; 2805 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2806 bsm = bootstrap_specifier; 2807 } else { 2808 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2809 assert(args->length() == 2, ""); 2810 bsm = Handle(THREAD, args->obj_at(0)); 2811 info = Handle(THREAD, args->obj_at(1)); 2812 } 2813 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2814 "caller must supply a valid BSM"); 2815 2816 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2817 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2818 2819 // This should not happen. JDK code should take care of that. 2820 if (caller == NULL || method_type.is_null()) { 2821 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2822 } 2823 2824 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2825 assert(appendix_box->obj_at(0) == NULL, ""); 2826 2827 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2828 JavaCallArguments args; 2829 args.push_oop(Handle(THREAD, caller->java_mirror())); 2830 args.push_int(indy_index); 2831 args.push_oop(bsm); 2832 args.push_oop(method_name); 2833 args.push_oop(method_type); 2834 args.push_oop(info); 2835 args.push_oop(appendix_box); 2836 JavaValue result(T_OBJECT); 2837 JavaCalls::call_static(&result, 2838 SystemDictionary::MethodHandleNatives_klass(), 2839 vmSymbols::linkCallSite_name(), 2840 vmSymbols::linkCallSite_signature(), 2841 &args, CHECK_(empty)); 2842 Handle mname(THREAD, (oop) result.get_jobject()); 2843 (*method_type_result) = method_type; 2844 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2845 } 2846 2847 // Protection domain cache table handling 2848 2849 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2850 return _pd_cache_table->get(protection_domain); 2851 } 2852 2853 #if INCLUDE_CDS 2854 void SystemDictionary::reorder_dictionary_for_sharing() { 2855 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); 2856 } 2857 #endif 2858 2859 size_t SystemDictionary::count_bytes_for_buckets() { 2860 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); 2861 } 2862 2863 size_t SystemDictionary::count_bytes_for_table() { 2864 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); 2865 } 2866 2867 void SystemDictionary::copy_buckets(char* top, char* end) { 2868 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2869 } 2870 2871 void SystemDictionary::copy_table(char* top, char* end) { 2872 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2873 } 2874 2875 // ---------------------------------------------------------------------------- 2876 void SystemDictionary::print_shared(outputStream *st) { 2877 shared_dictionary()->print_on(st); 2878 } 2879 2880 void SystemDictionary::print_on(outputStream *st) { 2881 if (shared_dictionary() != NULL) { 2882 st->print_cr("Shared Dictionary"); 2883 shared_dictionary()->print_on(st); 2884 st->cr(); 2885 } 2886 2887 GCMutexLocker mu(SystemDictionary_lock); 2888 2889 ClassLoaderDataGraph::print_dictionary(st); 2890 2891 // Placeholders 2892 placeholders()->print_on(st); 2893 st->cr(); 2894 2895 // loader constraints - print under SD_lock 2896 constraints()->print_on(st); 2897 st->cr(); 2898 2899 _pd_cache_table->print_on(st); 2900 st->cr(); 2901 } 2902 2903 void SystemDictionary::verify() { 2904 guarantee(constraints() != NULL, 2905 "Verify of loader constraints failed"); 2906 guarantee(placeholders()->number_of_entries() >= 0, 2907 "Verify of placeholders failed"); 2908 2909 GCMutexLocker mu(SystemDictionary_lock); 2910 2911 // Verify dictionary 2912 ClassLoaderDataGraph::verify_dictionary(); 2913 2914 placeholders()->verify(); 2915 2916 // Verify constraint table 2917 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2918 constraints()->verify(placeholders()); 2919 2920 _pd_cache_table->verify(); 2921 } 2922 2923 void SystemDictionary::dump(outputStream *st, bool verbose) { 2924 assert_locked_or_safepoint(SystemDictionary_lock); 2925 if (verbose) { 2926 print_on(st); 2927 } else { 2928 if (shared_dictionary() != NULL) { 2929 shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); 2930 } 2931 ClassLoaderDataGraph::print_dictionary_statistics(st); 2932 placeholders()->print_table_statistics(st, "Placeholder Table"); 2933 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 2934 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 2935 } 2936 } 2937 2938 // Utility for dumping dictionaries. 2939 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 2940 DCmdWithParser(output, heap), 2941 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 2942 "BOOLEAN", false, "false") { 2943 _dcmdparser.add_dcmd_option(&_verbose); 2944 } 2945 2946 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 2947 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 2948 _verbose.value()); 2949 VMThread::execute(&dumper); 2950 } 2951 2952 int SystemDictionaryDCmd::num_arguments() { 2953 ResourceMark rm; 2954 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 2955 if (dcmd != NULL) { 2956 DCmdMark mark(dcmd); 2957 return dcmd->_dcmdparser.num_arguments(); 2958 } else { 2959 return 0; 2960 } 2961 } 2962 2963 class CombineDictionariesClosure : public CLDClosure { 2964 private: 2965 Dictionary* _master_dictionary; 2966 public: 2967 CombineDictionariesClosure(Dictionary* master_dictionary) : 2968 _master_dictionary(master_dictionary) {} 2969 void do_cld(ClassLoaderData* cld) { 2970 ResourceMark rm; 2971 if (cld->is_anonymous()) { 2972 return; 2973 } 2974 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 2975 for (int i = 0; i < cld->dictionary()->table_size(); ++i) { 2976 Dictionary* curr_dictionary = cld->dictionary(); 2977 DictionaryEntry* p = curr_dictionary->bucket(i); 2978 while (p != NULL) { 2979 Symbol* name = p->instance_klass()->name(); 2980 unsigned int d_hash = _master_dictionary->compute_hash(name); 2981 int d_index = _master_dictionary->hash_to_index(d_hash); 2982 DictionaryEntry* next = p->next(); 2983 if (p->literal()->class_loader_data() != cld) { 2984 // This is an initiating class loader entry; don't use it 2985 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); 2986 curr_dictionary->free_entry(p); 2987 } else { 2988 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); 2989 curr_dictionary->unlink_entry(p); 2990 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. 2991 _master_dictionary->add_entry(d_index, p); 2992 } 2993 p = next; 2994 } 2995 *curr_dictionary->bucket_addr(i) = NULL; 2996 } 2997 } 2998 } 2999 }; 3000 3001 // Combining platform and system loader dictionaries into boot loader dictionary. 3002 // During run time, we only have one shared dictionary. 3003 void SystemDictionary::combine_shared_dictionaries() { 3004 assert(DumpSharedSpaces, "dump time only"); 3005 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); 3006 CombineDictionariesClosure cdc(master_dictionary); 3007 ClassLoaderDataGraph::cld_do(&cdc); 3008 3009 // These tables are no longer valid or necessary. Keeping them around will 3010 // cause SystemDictionary::verify() to fail. Let's empty them. 3011 _placeholders = new PlaceholderTable(_placeholder_table_size); 3012 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 3013 3014 NOT_PRODUCT(SystemDictionary::verify()); 3015 } 3016 3017 void SystemDictionary::initialize_oop_storage() { 3018 _vm_weak_oop_storage = 3019 new OopStorage("VM Weak Oop Handles", 3020 VMWeakAlloc_lock, 3021 VMWeakActive_lock); 3022 } 3023 3024 OopStorage* SystemDictionary::vm_weak_oop_storage() { 3025 assert(_vm_weak_oop_storage != NULL, "Uninitialized"); 3026 return _vm_weak_oop_storage; 3027 }