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/jvmtiExport.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 but we may have to remove entry from the placeholder table below. 833 if (!HAS_PENDING_EXCEPTION) { 834 // Record dependency for non-parent delegation. 835 // This recording keeps the defining class loader of the klass (k) found 836 // from being unloaded while the initiating class loader is loaded 837 // even if the reference to the defining class loader is dropped 838 // before references to the initiating class loader. 839 loader_data->record_dependency(k); 840 841 { // Grabbing the Compile_lock prevents systemDictionary updates 842 // during compilations. 843 MutexLocker mu(Compile_lock, THREAD); 844 update_dictionary(d_hash, p_index, p_hash, 845 k, class_loader, THREAD); 846 } 847 848 if (JvmtiExport::should_post_class_load()) { 849 Thread *thread = THREAD; 850 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 851 JvmtiExport::post_class_load((JavaThread *) thread, k); 852 } 853 } 854 } 855 } // load_instance_class 856 857 if (load_instance_added == true) { 858 // clean up placeholder entries for LOAD_INSTANCE success or error 859 // This brackets the SystemDictionary updates for both defining 860 // and initiating loaders 861 MutexLocker mu(SystemDictionary_lock, THREAD); 862 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 863 SystemDictionary_lock->notify_all(); 864 } 865 } 866 867 if (HAS_PENDING_EXCEPTION || k == NULL) { 868 return NULL; 869 } 870 if (class_load_start_event.should_commit()) { 871 post_class_load_event(&class_load_start_event, k, loader_data); 872 } 873 #ifdef ASSERT 874 { 875 ClassLoaderData* loader_data = k->class_loader_data(); 876 MutexLocker mu(SystemDictionary_lock, THREAD); 877 Klass* kk = find_class(name, loader_data); 878 assert(kk == k, "should be present in dictionary"); 879 } 880 #endif 881 882 // return if the protection domain in NULL 883 if (protection_domain() == NULL) return k; 884 885 // Check the protection domain has the right access 886 if (dictionary->is_valid_protection_domain(d_hash, name, 887 protection_domain)) { 888 return k; 889 } 890 891 // Verify protection domain. If it fails an exception is thrown 892 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 893 894 return k; 895 } 896 897 898 // This routine does not lock the system dictionary. 899 // 900 // Since readers don't hold a lock, we must make sure that system 901 // dictionary entries are only removed at a safepoint (when only one 902 // thread is running), and are added to in a safe way (all links must 903 // be updated in an MT-safe manner). 904 // 905 // Callers should be aware that an entry could be added just after 906 // _dictionary->bucket(index) is read here, so the caller will not see 907 // the new entry. 908 909 Klass* SystemDictionary::find(Symbol* class_name, 910 Handle class_loader, 911 Handle protection_domain, 912 TRAPS) { 913 914 // The result of this call should be consistent with the result 915 // of the call to resolve_instance_class_or_null(). 916 // See evaluation 6790209 and 4474172 for more details. 917 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 918 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 919 920 if (loader_data == NULL) { 921 // If the ClassLoaderData has not been setup, 922 // then the class loader has no entries in the dictionary. 923 return NULL; 924 } 925 926 Dictionary* dictionary = loader_data->dictionary(); 927 unsigned int d_hash = dictionary->compute_hash(class_name); 928 return dictionary->find(d_hash, class_name, 929 protection_domain); 930 } 931 932 933 // Look for a loaded instance or array klass by name. Do not do any loading. 934 // return NULL in case of error. 935 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 936 Handle class_loader, 937 Handle protection_domain, 938 TRAPS) { 939 Klass* k = NULL; 940 assert(class_name != NULL, "class name must be non NULL"); 941 942 if (FieldType::is_array(class_name)) { 943 // The name refers to an array. Parse the name. 944 // dimension and object_key in FieldArrayInfo are assigned as a 945 // side-effect of this call 946 FieldArrayInfo fd; 947 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 948 if (t != T_OBJECT) { 949 k = Universe::typeArrayKlassObj(t); 950 } else { 951 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 952 } 953 if (k != NULL) { 954 k = k->array_klass_or_null(fd.dimension()); 955 } 956 } else { 957 k = find(class_name, class_loader, protection_domain, THREAD); 958 } 959 return k; 960 } 961 962 // Note: this method is much like resolve_from_stream, but 963 // does not publish the classes via the SystemDictionary. 964 // Handles unsafe_DefineAnonymousClass and redefineclasses 965 // RedefinedClasses do not add to the class hierarchy 966 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, 967 Handle class_loader, 968 Handle protection_domain, 969 ClassFileStream* st, 970 const InstanceKlass* host_klass, 971 GrowableArray<Handle>* cp_patches, 972 TRAPS) { 973 974 EventClassLoad class_load_start_event; 975 976 ClassLoaderData* loader_data; 977 if (host_klass != NULL) { 978 // Create a new CLD for anonymous class, that uses the same class loader 979 // as the host_klass 980 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same"); 981 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader); 982 } else { 983 loader_data = ClassLoaderData::class_loader_data(class_loader()); 984 } 985 986 assert(st != NULL, "invariant"); 987 assert(st->need_verify(), "invariant"); 988 989 // Parse stream and create a klass. 990 // Note that we do this even though this klass might 991 // already be present in the SystemDictionary, otherwise we would not 992 // throw potential ClassFormatErrors. 993 994 InstanceKlass* k = KlassFactory::create_from_stream(st, 995 class_name, 996 loader_data, 997 protection_domain, 998 host_klass, 999 cp_patches, 1000 CHECK_NULL); 1001 1002 if (host_klass != NULL && k != NULL) { 1003 // Anonymous classes must update ClassLoaderData holder (was host_klass loader) 1004 // so that they can be unloaded when the mirror is no longer referenced. 1005 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror())); 1006 1007 { 1008 MutexLocker mu_r(Compile_lock, THREAD); 1009 1010 // Add to class hierarchy, initialize vtables, and do possible 1011 // deoptimizations. 1012 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1013 1014 // But, do not add to dictionary. 1015 1016 // compiled code dependencies need to be validated anyway 1017 notice_modification(); 1018 } 1019 1020 // Rewrite and patch constant pool here. 1021 k->link_class(CHECK_NULL); 1022 if (cp_patches != NULL) { 1023 k->constants()->patch_resolved_references(cp_patches); 1024 } 1025 1026 // If it's anonymous, initialize it now, since nobody else will. 1027 k->eager_initialize(CHECK_NULL); 1028 1029 // notify jvmti 1030 if (JvmtiExport::should_post_class_load()) { 1031 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1032 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1033 } 1034 if (class_load_start_event.should_commit()) { 1035 post_class_load_event(&class_load_start_event, k, loader_data); 1036 } 1037 } 1038 assert(host_klass != NULL || NULL == cp_patches, 1039 "cp_patches only found with host_klass"); 1040 1041 return k; 1042 } 1043 1044 // Add a klass to the system from a stream (called by jni_DefineClass and 1045 // JVM_DefineClass). 1046 // Note: class_name can be NULL. In that case we do not know the name of 1047 // the class until we have parsed the stream. 1048 1049 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1050 Handle class_loader, 1051 Handle protection_domain, 1052 ClassFileStream* st, 1053 TRAPS) { 1054 1055 HandleMark hm(THREAD); 1056 1057 // Classloaders that support parallelism, e.g. bootstrap classloader, 1058 // do not acquire lock here 1059 bool DoObjectLock = true; 1060 if (is_parallelCapable(class_loader)) { 1061 DoObjectLock = false; 1062 } 1063 1064 ClassLoaderData* loader_data = register_loader(class_loader); 1065 1066 // Make sure we are synchronized on the class loader before we proceed 1067 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1068 check_loader_lock_contention(lockObject, THREAD); 1069 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1070 1071 assert(st != NULL, "invariant"); 1072 1073 // Parse the stream and create a klass. 1074 // Note that we do this even though this klass might 1075 // already be present in the SystemDictionary, otherwise we would not 1076 // throw potential ClassFormatErrors. 1077 InstanceKlass* k = NULL; 1078 1079 #if INCLUDE_CDS 1080 if (!DumpSharedSpaces) { 1081 k = SystemDictionaryShared::lookup_from_stream(class_name, 1082 class_loader, 1083 protection_domain, 1084 st, 1085 CHECK_NULL); 1086 } 1087 #endif 1088 1089 if (k == NULL) { 1090 if (st->buffer() == NULL) { 1091 return NULL; 1092 } 1093 k = KlassFactory::create_from_stream(st, 1094 class_name, 1095 loader_data, 1096 protection_domain, 1097 NULL, // host_klass 1098 NULL, // cp_patches 1099 CHECK_NULL); 1100 } 1101 1102 assert(k != NULL, "no klass created"); 1103 Symbol* h_name = k->name(); 1104 assert(class_name == NULL || class_name == h_name, "name mismatch"); 1105 1106 // Add class just loaded 1107 // If a class loader supports parallel classloading handle parallel define requests 1108 // find_or_define_instance_class may return a different InstanceKlass 1109 if (is_parallelCapable(class_loader)) { 1110 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); 1111 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1112 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1113 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1114 loader_data->add_to_deallocate_list(k); 1115 k = defined_k; 1116 } 1117 } else { 1118 define_instance_class(k, THREAD); 1119 } 1120 1121 // If defining the class throws an exception register 'k' for cleanup. 1122 if (HAS_PENDING_EXCEPTION) { 1123 assert(k != NULL, "Must have an instance klass here!"); 1124 loader_data->add_to_deallocate_list(k); 1125 return NULL; 1126 } 1127 1128 // Make sure we have an entry in the SystemDictionary on success 1129 debug_only( { 1130 MutexLocker mu(SystemDictionary_lock, THREAD); 1131 1132 Klass* check = find_class(h_name, k->class_loader_data()); 1133 assert(check == k, "should be present in the dictionary"); 1134 } ); 1135 1136 return k; 1137 } 1138 1139 #if INCLUDE_CDS 1140 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1141 int number_of_entries) { 1142 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>), 1143 "bad shared dictionary size."); 1144 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), 1145 _shared_dictionary_size, t, number_of_entries); 1146 } 1147 1148 1149 // If there is a shared dictionary, then find the entry for the 1150 // given shared system class, if any. 1151 1152 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { 1153 if (shared_dictionary() != NULL) { 1154 unsigned int d_hash = shared_dictionary()->compute_hash(class_name); 1155 int d_index = shared_dictionary()->hash_to_index(d_hash); 1156 1157 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1158 } else { 1159 return NULL; 1160 } 1161 } 1162 1163 1164 // Load a class from the shared spaces (found through the shared system 1165 // dictionary). Force the superclass and all interfaces to be loaded. 1166 // Update the class definition to include sibling classes and no 1167 // subclasses (yet). [Classes in the shared space are not part of the 1168 // object hierarchy until loaded.] 1169 1170 InstanceKlass* SystemDictionary::load_shared_class( 1171 Symbol* class_name, Handle class_loader, TRAPS) { 1172 InstanceKlass* ik = find_shared_class(class_name); 1173 // Make sure we only return the boot class for the NULL classloader. 1174 if (ik != NULL && 1175 ik->is_shared_boot_class() && class_loader.is_null()) { 1176 Handle protection_domain; 1177 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1178 } 1179 return NULL; 1180 } 1181 1182 // Check if a shared class can be loaded by the specific classloader: 1183 // 1184 // NULL classloader: 1185 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1186 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1187 // be defined in an unnamed module. 1188 bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1189 InstanceKlass* ik, 1190 Handle class_loader, TRAPS) { 1191 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), 1192 "Cannot use sharing if java.base is patched"); 1193 ResourceMark rm; 1194 int path_index = ik->shared_classpath_index(); 1195 ClassLoaderData* loader_data = class_loader_data(class_loader); 1196 if (path_index < 0) { 1197 // path_index < 0 indicates that the class is intended for a custom loader 1198 // and should not be loaded by boot/platform/app loaders 1199 if (loader_data->is_builtin_class_loader_data()) { 1200 return false; 1201 } else { 1202 return true; 1203 } 1204 } 1205 SharedClassPathEntry* ent = 1206 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); 1207 if (!Universe::is_module_initialized()) { 1208 assert(ent != NULL && ent->is_modules_image(), 1209 "Loading non-bootstrap classes before the module system is initialized"); 1210 assert(class_loader.is_null(), "sanity"); 1211 return true; 1212 } 1213 // Get the pkg_entry from the classloader 1214 TempNewSymbol pkg_name = NULL; 1215 PackageEntry* pkg_entry = NULL; 1216 ModuleEntry* mod_entry = NULL; 1217 const char* pkg_string = NULL; 1218 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1219 if (pkg_name != NULL) { 1220 pkg_string = pkg_name->as_C_string(); 1221 if (loader_data != NULL) { 1222 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1223 } 1224 if (pkg_entry != NULL) { 1225 mod_entry = pkg_entry->module(); 1226 } 1227 } 1228 1229 // If the archived class is from a module that has been patched at runtime, 1230 // the class cannot be loaded from the archive. 1231 if (mod_entry != NULL && mod_entry->is_patched()) { 1232 return false; 1233 } 1234 1235 if (class_loader.is_null()) { 1236 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); 1237 // The NULL classloader can load archived class originated from the 1238 // "modules" jimage and the -Xbootclasspath/a. For class from the 1239 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1240 // by the NULL classloader. 1241 if (mod_entry != NULL) { 1242 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1243 // ModuleEntry's location agrees with the archived class' origination. 1244 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { 1245 return true; // Module class from the "module" jimage 1246 } 1247 } 1248 1249 // If the archived class is not from the "module" jimage, the class can be 1250 // loaded by the NULL classloader if 1251 // 1252 // 1. the class is from the unamed package 1253 // 2. or, the class is not from a module defined in the NULL classloader 1254 // 3. or, the class is from an unamed module 1255 if (!ent->is_modules_image() && ik->is_shared_boot_class()) { 1256 // the class is from the -Xbootclasspath/a 1257 if (pkg_string == NULL || 1258 pkg_entry == NULL || 1259 pkg_entry->in_unnamed_module()) { 1260 assert(mod_entry == NULL || 1261 mod_entry == loader_data->unnamed_module(), 1262 "the unnamed module is not defined in the classloader"); 1263 return true; 1264 } 1265 } 1266 return false; 1267 } else { 1268 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1269 ik, class_loader, pkg_string, pkg_name, 1270 pkg_entry, mod_entry, CHECK_(false)); 1271 return res; 1272 } 1273 } 1274 1275 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, 1276 Handle class_loader, 1277 Handle protection_domain, TRAPS) { 1278 1279 if (ik != NULL) { 1280 Symbol* class_name = ik->name(); 1281 1282 bool visible = is_shared_class_visible( 1283 class_name, ik, class_loader, CHECK_NULL); 1284 if (!visible) { 1285 return NULL; 1286 } 1287 1288 // Resolve the superclass and interfaces. They must be the same 1289 // as in dump time, because the layout of <ik> depends on 1290 // the specific layout of ik->super() and ik->local_interfaces(). 1291 // 1292 // If unexpected superclass or interfaces are found, we cannot 1293 // load <ik> from the shared archive. 1294 1295 if (ik->super() != NULL) { 1296 Symbol* cn = ik->super()->name(); 1297 Klass *s = resolve_super_or_fail(class_name, cn, 1298 class_loader, protection_domain, true, CHECK_NULL); 1299 if (s != ik->super()) { 1300 // The dynamically resolved super class is not the same as the one we used during dump time, 1301 // so we cannot use ik. 1302 return NULL; 1303 } else { 1304 assert(s->is_shared(), "must be"); 1305 } 1306 } 1307 1308 Array<Klass*>* interfaces = ik->local_interfaces(); 1309 int num_interfaces = interfaces->length(); 1310 for (int index = 0; index < num_interfaces; index++) { 1311 Klass* k = interfaces->at(index); 1312 Symbol* name = k->name(); 1313 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); 1314 if (k != i) { 1315 // The dynamically resolved interface class is not the same as the one we used during dump time, 1316 // so we cannot use ik. 1317 return NULL; 1318 } else { 1319 assert(i->is_shared(), "must be"); 1320 } 1321 } 1322 1323 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( 1324 ik, class_name, class_loader, protection_domain, CHECK_NULL); 1325 if (new_ik != NULL) { 1326 // The class is changed by CFLH. Return the new class. The shared class is 1327 // not used. 1328 return new_ik; 1329 } 1330 1331 // Adjust methods to recover missing data. They need addresses for 1332 // interpreter entry points and their default native method address 1333 // must be reset. 1334 1335 // Updating methods must be done under a lock so multiple 1336 // threads don't update these in parallel 1337 // 1338 // Shared classes are all currently loaded by either the bootstrap or 1339 // internal parallel class loaders, so this will never cause a deadlock 1340 // on a custom class loader lock. 1341 1342 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1343 { 1344 HandleMark hm(THREAD); 1345 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1346 check_loader_lock_contention(lockObject, THREAD); 1347 ObjectLocker ol(lockObject, THREAD, true); 1348 // prohibited package check assumes all classes loaded from archive call 1349 // restore_unshareable_info which calls ik->set_package() 1350 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); 1351 } 1352 1353 ik->print_class_load_logging(loader_data, NULL, NULL); 1354 1355 // For boot loader, ensure that GetSystemPackage knows that a class in this 1356 // package was loaded. 1357 if (class_loader.is_null()) { 1358 int path_index = ik->shared_classpath_index(); 1359 ResourceMark rm; 1360 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1361 } 1362 1363 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1364 // Only dump the classes that can be stored into CDS archive 1365 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1366 ResourceMark rm(THREAD); 1367 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1368 classlist_file->flush(); 1369 } 1370 } 1371 1372 // notify a class loaded from shared object 1373 ClassLoadingService::notify_class_loaded(ik, true /* shared class */); 1374 1375 ik->set_has_passed_fingerprint_check(false); 1376 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { 1377 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); 1378 uint64_t cds_fp = ik->get_stored_fingerprint(); 1379 if (aot_fp != 0 && aot_fp == cds_fp) { 1380 // This class matches with a class saved in an AOT library 1381 ik->set_has_passed_fingerprint_check(true); 1382 } else { 1383 ResourceMark rm; 1384 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); 1385 } 1386 } 1387 } 1388 return ik; 1389 } 1390 1391 void SystemDictionary::clear_invoke_method_table() { 1392 SymbolPropertyEntry* spe = NULL; 1393 for (int index = 0; index < _invoke_method_table->table_size(); index++) { 1394 SymbolPropertyEntry* p = _invoke_method_table->bucket(index); 1395 while (p != NULL) { 1396 spe = p; 1397 p = p->next(); 1398 _invoke_method_table->free_entry(spe); 1399 } 1400 } 1401 } 1402 #endif // INCLUDE_CDS 1403 1404 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1405 1406 if (class_loader.is_null()) { 1407 ResourceMark rm; 1408 PackageEntry* pkg_entry = NULL; 1409 bool search_only_bootloader_append = false; 1410 ClassLoaderData *loader_data = class_loader_data(class_loader); 1411 1412 // Find the package in the boot loader's package entry table. 1413 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1414 if (pkg_name != NULL) { 1415 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1416 } 1417 1418 // Prior to attempting to load the class, enforce the boot loader's 1419 // visibility boundaries. 1420 if (!Universe::is_module_initialized()) { 1421 // During bootstrapping, prior to module initialization, any 1422 // class attempting to be loaded must be checked against the 1423 // java.base packages in the boot loader's PackageEntryTable. 1424 // No class outside of java.base is allowed to be loaded during 1425 // this bootstrapping window. 1426 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1427 // Class is either in the unnamed package or in 1428 // a named package within the unnamed module. Either 1429 // case is outside of java.base, do not attempt to 1430 // load the class post java.base definition. If 1431 // java.base has not been defined, let the class load 1432 // and its package will be checked later by 1433 // ModuleEntryTable::verify_javabase_packages. 1434 if (ModuleEntryTable::javabase_defined()) { 1435 return NULL; 1436 } 1437 } else { 1438 // Check that the class' package is defined within java.base. 1439 ModuleEntry* mod_entry = pkg_entry->module(); 1440 Symbol* mod_entry_name = mod_entry->name(); 1441 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1442 return NULL; 1443 } 1444 } 1445 } else { 1446 // After the module system has been initialized, check if the class' 1447 // package is in a module defined to the boot loader. 1448 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1449 // Class is either in the unnamed package, in a named package 1450 // within a module not defined to the boot loader or in a 1451 // a named package within the unnamed module. In all cases, 1452 // limit visibility to search for the class only in the boot 1453 // loader's append path. 1454 search_only_bootloader_append = true; 1455 } 1456 } 1457 1458 // Prior to bootstrapping's module initialization, never load a class outside 1459 // of the boot loader's module path 1460 assert(Universe::is_module_initialized() || 1461 !search_only_bootloader_append, 1462 "Attempt to load a class outside of boot loader's module path"); 1463 1464 // Search for classes in the CDS archive. 1465 InstanceKlass* k = NULL; 1466 { 1467 #if INCLUDE_CDS 1468 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1469 k = load_shared_class(class_name, class_loader, THREAD); 1470 #endif 1471 } 1472 1473 if (k == NULL) { 1474 // Use VM class loader 1475 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1476 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); 1477 } 1478 1479 // find_or_define_instance_class may return a different InstanceKlass 1480 if (k != NULL) { 1481 InstanceKlass* defined_k = 1482 find_or_define_instance_class(class_name, class_loader, k, THREAD); 1483 if (!HAS_PENDING_EXCEPTION && defined_k != k) { 1484 // If a parallel capable class loader already defined this class, register 'k' for cleanup. 1485 assert(defined_k != NULL, "Should have a klass if there's no exception"); 1486 loader_data->add_to_deallocate_list(k); 1487 k = defined_k; 1488 } else if (HAS_PENDING_EXCEPTION) { 1489 loader_data->add_to_deallocate_list(k); 1490 return NULL; 1491 } 1492 } 1493 return k; 1494 } else { 1495 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1496 ResourceMark rm(THREAD); 1497 1498 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1499 JavaThread* jt = (JavaThread*) THREAD; 1500 1501 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1502 ClassLoader::perf_app_classload_selftime(), 1503 ClassLoader::perf_app_classload_count(), 1504 jt->get_thread_stat()->perf_recursion_counts_addr(), 1505 jt->get_thread_stat()->perf_timers_addr(), 1506 PerfClassTraceTime::CLASS_LOAD); 1507 1508 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); 1509 // Translate to external class name format, i.e., convert '/' chars to '.' 1510 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); 1511 1512 JavaValue result(T_OBJECT); 1513 1514 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); 1515 1516 // Call public unsynchronized loadClass(String) directly for all class loaders. 1517 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will 1518 // acquire a class-name based lock rather than the class loader object lock. 1519 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). 1520 JavaCalls::call_virtual(&result, 1521 class_loader, 1522 spec_klass, 1523 vmSymbols::loadClass_name(), 1524 vmSymbols::string_class_signature(), 1525 string, 1526 CHECK_NULL); 1527 1528 assert(result.get_type() == T_OBJECT, "just checking"); 1529 oop obj = (oop) result.get_jobject(); 1530 1531 // Primitive classes return null since forName() can not be 1532 // used to obtain any of the Class objects representing primitives or void 1533 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1534 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); 1535 // For user defined Java class loaders, check that the name returned is 1536 // the same as that requested. This check is done for the bootstrap 1537 // loader when parsing the class file. 1538 if (class_name == k->name()) { 1539 return k; 1540 } 1541 } 1542 // Class is not found or has the wrong name, return NULL 1543 return NULL; 1544 } 1545 } 1546 1547 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) { 1548 EventClassDefine event; 1549 if (event.should_commit()) { 1550 event.set_definedClass(k); 1551 event.set_definingClassLoader(def_cld); 1552 event.commit(); 1553 } 1554 } 1555 1556 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { 1557 1558 HandleMark hm(THREAD); 1559 ClassLoaderData* loader_data = k->class_loader_data(); 1560 Handle class_loader_h(THREAD, loader_data->class_loader()); 1561 1562 // for bootstrap and other parallel classloaders don't acquire lock, 1563 // use placeholder token 1564 // If a parallelCapable class loader calls define_instance_class instead of 1565 // find_or_define_instance_class to get here, we have a timing 1566 // hole with systemDictionary updates and check_constraints 1567 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1568 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1569 compute_loader_lock_object(class_loader_h, THREAD)), 1570 "define called without lock"); 1571 } 1572 1573 // Check class-loading constraints. Throw exception if violation is detected. 1574 // Grabs and releases SystemDictionary_lock 1575 // The check_constraints/find_class call and update_dictionary sequence 1576 // must be "atomic" for a specific class/classloader pair so we never 1577 // define two different instanceKlasses for that class/classloader pair. 1578 // Existing classloaders will call define_instance_class with the 1579 // classloader lock held 1580 // Parallel classloaders will call find_or_define_instance_class 1581 // which will require a token to perform the define class 1582 Symbol* name_h = k->name(); 1583 Dictionary* dictionary = loader_data->dictionary(); 1584 unsigned int d_hash = dictionary->compute_hash(name_h); 1585 check_constraints(d_hash, k, class_loader_h, true, CHECK); 1586 1587 // Register class just loaded with class loader (placed in Vector) 1588 // Note we do this before updating the dictionary, as this can 1589 // fail with an OutOfMemoryError (if it does, we will *not* put this 1590 // class in the dictionary and will not update the class hierarchy). 1591 // JVMTI FollowReferences needs to find the classes this way. 1592 if (k->class_loader() != NULL) { 1593 methodHandle m(THREAD, Universe::loader_addClass_method()); 1594 JavaValue result(T_VOID); 1595 JavaCallArguments args(class_loader_h); 1596 args.push_oop(Handle(THREAD, k->java_mirror())); 1597 JavaCalls::call(&result, m, &args, CHECK); 1598 } 1599 1600 // Add the new class. We need recompile lock during update of CHA. 1601 { 1602 unsigned int p_hash = placeholders()->compute_hash(name_h); 1603 int p_index = placeholders()->hash_to_index(p_hash); 1604 1605 MutexLocker mu_r(Compile_lock, THREAD); 1606 1607 // Add to class hierarchy, initialize vtables, and do possible 1608 // deoptimizations. 1609 add_to_hierarchy(k, CHECK); // No exception, but can block 1610 1611 // Add to systemDictionary - so other classes can see it. 1612 // Grabs and releases SystemDictionary_lock 1613 update_dictionary(d_hash, p_index, p_hash, 1614 k, class_loader_h, THREAD); 1615 } 1616 k->eager_initialize(THREAD); 1617 1618 // notify jvmti 1619 if (JvmtiExport::should_post_class_load()) { 1620 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1621 JvmtiExport::post_class_load((JavaThread *) THREAD, k); 1622 1623 } 1624 post_class_define_event(k, loader_data); 1625 } 1626 1627 // Support parallel classloading 1628 // All parallel class loaders, including bootstrap classloader 1629 // lock a placeholder entry for this class/class_loader pair 1630 // to allow parallel defines of different classes for this class loader 1631 // With AllowParallelDefine flag==true, in case they do not synchronize around 1632 // FindLoadedClass/DefineClass, calls, we check for parallel 1633 // loading for them, wait if a defineClass is in progress 1634 // and return the initial requestor's results 1635 // This flag does not apply to the bootstrap classloader. 1636 // With AllowParallelDefine flag==false, call through to define_instance_class 1637 // which will throw LinkageError: duplicate class definition. 1638 // False is the requested default. 1639 // For better performance, the class loaders should synchronize 1640 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1641 // potentially waste time reading and parsing the bytestream. 1642 // Note: VM callers should ensure consistency of k/class_name,class_loader 1643 // Be careful when modifying this code: once you have run 1644 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), 1645 // you need to find_and_remove it before returning. 1646 // So be careful to not exit with a CHECK_ macro betweeen these calls. 1647 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, 1648 InstanceKlass* k, TRAPS) { 1649 1650 Symbol* name_h = k->name(); // passed in class_name may be null 1651 ClassLoaderData* loader_data = class_loader_data(class_loader); 1652 Dictionary* dictionary = loader_data->dictionary(); 1653 1654 unsigned int d_hash = dictionary->compute_hash(name_h); 1655 1656 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1657 unsigned int p_hash = placeholders()->compute_hash(name_h); 1658 int p_index = placeholders()->hash_to_index(p_hash); 1659 PlaceholderEntry* probe; 1660 1661 { 1662 MutexLocker mu(SystemDictionary_lock, THREAD); 1663 // First check if class already defined 1664 if (is_parallelDefine(class_loader)) { 1665 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1666 if (check != NULL) { 1667 return check; 1668 } 1669 } 1670 1671 // Acquire define token for this class/classloader 1672 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1673 // Wait if another thread defining in parallel 1674 // All threads wait - even those that will throw duplicate class: otherwise 1675 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1676 // if other thread has not finished updating dictionary 1677 while (probe->definer() != NULL) { 1678 SystemDictionary_lock->wait(); 1679 } 1680 // Only special cases allow parallel defines and can use other thread's results 1681 // Other cases fall through, and may run into duplicate defines 1682 // caught by finding an entry in the SystemDictionary 1683 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { 1684 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1685 SystemDictionary_lock->notify_all(); 1686 #ifdef ASSERT 1687 InstanceKlass* check = find_class(d_hash, name_h, dictionary); 1688 assert(check != NULL, "definer missed recording success"); 1689 #endif 1690 return probe->instance_klass(); 1691 } else { 1692 // This thread will define the class (even if earlier thread tried and had an error) 1693 probe->set_definer(THREAD); 1694 } 1695 } 1696 1697 define_instance_class(k, THREAD); 1698 1699 Handle linkage_exception = Handle(); // null handle 1700 1701 // definer must notify any waiting threads 1702 { 1703 MutexLocker mu(SystemDictionary_lock, THREAD); 1704 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1705 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1706 if (probe != NULL) { 1707 if (HAS_PENDING_EXCEPTION) { 1708 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1709 CLEAR_PENDING_EXCEPTION; 1710 } else { 1711 probe->set_instance_klass(k); 1712 } 1713 probe->set_definer(NULL); 1714 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1715 SystemDictionary_lock->notify_all(); 1716 } 1717 } 1718 1719 // Can't throw exception while holding lock due to rank ordering 1720 if (linkage_exception() != NULL) { 1721 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns 1722 } 1723 1724 return k; 1725 } 1726 1727 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1728 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1729 if (class_loader.is_null()) { 1730 return Handle(THREAD, _system_loader_lock_obj); 1731 } else { 1732 return class_loader; 1733 } 1734 } 1735 1736 // This method is added to check how often we have to wait to grab loader 1737 // lock. The results are being recorded in the performance counters defined in 1738 // ClassLoader::_sync_systemLoaderLockContentionRate and 1739 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1740 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1741 if (!UsePerfData) { 1742 return; 1743 } 1744 1745 assert(!loader_lock.is_null(), "NULL lock object"); 1746 1747 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1748 == ObjectSynchronizer::owner_other) { 1749 // contention will likely happen, so increment the corresponding 1750 // contention counter. 1751 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) { 1752 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1753 } else { 1754 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1755 } 1756 } 1757 } 1758 1759 // ---------------------------------------------------------------------------- 1760 // Lookup 1761 1762 InstanceKlass* SystemDictionary::find_class(unsigned int hash, 1763 Symbol* class_name, 1764 Dictionary* dictionary) { 1765 assert_locked_or_safepoint(SystemDictionary_lock); 1766 int index = dictionary->hash_to_index(hash); 1767 return dictionary->find_class(index, hash, class_name); 1768 } 1769 1770 1771 // Basic find on classes in the midst of being loaded 1772 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1773 ClassLoaderData* loader_data) { 1774 assert_locked_or_safepoint(SystemDictionary_lock); 1775 unsigned int p_hash = placeholders()->compute_hash(class_name); 1776 int p_index = placeholders()->hash_to_index(p_hash); 1777 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1778 } 1779 1780 1781 // Used for assertions and verification only 1782 // Precalculating the hash and index is an optimization because there are many lookups 1783 // before adding the class. 1784 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1785 assert_locked_or_safepoint(SystemDictionary_lock); 1786 #ifndef ASSERT 1787 guarantee(VerifyBeforeGC || 1788 VerifyDuringGC || 1789 VerifyBeforeExit || 1790 VerifyDuringStartup || 1791 VerifyAfterGC, "too expensive"); 1792 #endif 1793 1794 Dictionary* dictionary = loader_data->dictionary(); 1795 unsigned int d_hash = dictionary->compute_hash(class_name); 1796 return find_class(d_hash, class_name, dictionary); 1797 } 1798 1799 1800 // ---------------------------------------------------------------------------- 1801 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1802 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1803 // before a new class is used. 1804 1805 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { 1806 assert(k != NULL, "just checking"); 1807 assert_locked_or_safepoint(Compile_lock); 1808 1809 // Link into hierachy. Make sure the vtables are initialized before linking into 1810 k->append_to_sibling_list(); // add to superklass/sibling list 1811 k->process_interfaces(THREAD); // handle all "implements" declarations 1812 k->set_init_state(InstanceKlass::loaded); 1813 // Now flush all code that depended on old class hierarchy. 1814 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1815 // Also, first reinitialize vtable because it may have gotten out of synch 1816 // while the new class wasn't connected to the class hierarchy. 1817 CodeCache::flush_dependents_on(k); 1818 } 1819 1820 // ---------------------------------------------------------------------------- 1821 // GC support 1822 1823 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1824 // Note: anonymous classes are not in the SD. 1825 bool SystemDictionary::do_unloading(GCTimer* gc_timer, 1826 bool do_cleaning) { 1827 1828 bool unloading_occurred; 1829 { 1830 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); 1831 1832 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1833 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning); 1834 } 1835 1836 if (unloading_occurred) { 1837 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); 1838 constraints()->purge_loader_constraints(); 1839 resolution_errors()->purge_resolution_errors(); 1840 } 1841 1842 { 1843 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); 1844 // Oops referenced by the protection domain cache table may get unreachable independently 1845 // of the class loader (eg. cached protection domain oops). So we need to 1846 // explicitly unlink them here. 1847 _pd_cache_table->unlink(); 1848 } 1849 1850 if (do_cleaning) { 1851 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); 1852 ResolvedMethodTable::unlink(); 1853 } 1854 1855 return unloading_occurred; 1856 } 1857 1858 void SystemDictionary::oops_do(OopClosure* f) { 1859 f->do_oop(&_java_system_loader); 1860 f->do_oop(&_java_platform_loader); 1861 f->do_oop(&_system_loader_lock_obj); 1862 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1863 1864 // Visit extra methods 1865 invoke_method_table()->oops_do(f); 1866 } 1867 1868 // CDS: scan and relocate all classes in the system dictionary. 1869 void SystemDictionary::classes_do(MetaspaceClosure* it) { 1870 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); 1871 } 1872 1873 // CDS: scan and relocate all classes referenced by _well_known_klasses[]. 1874 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { 1875 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { 1876 it->push(well_known_klass_addr((WKID)id)); 1877 } 1878 } 1879 1880 void SystemDictionary::methods_do(void f(Method*)) { 1881 // Walk methods in loaded classes 1882 ClassLoaderDataGraph::methods_do(f); 1883 // Walk method handle intrinsics 1884 invoke_method_table()->methods_do(f); 1885 } 1886 1887 class RemoveClassesClosure : public CLDClosure { 1888 public: 1889 void do_cld(ClassLoaderData* cld) { 1890 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 1891 cld->dictionary()->remove_classes_in_error_state(); 1892 } 1893 } 1894 }; 1895 1896 void SystemDictionary::remove_classes_in_error_state() { 1897 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); 1898 RemoveClassesClosure rcc; 1899 ClassLoaderDataGraph::cld_do(&rcc); 1900 } 1901 1902 // ---------------------------------------------------------------------------- 1903 // Initialization 1904 1905 void SystemDictionary::initialize(TRAPS) { 1906 // Allocate arrays 1907 _placeholders = new PlaceholderTable(_placeholder_table_size); 1908 _number_of_modifications = 0; 1909 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1910 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1911 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1912 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); 1913 1914 // Allocate private object used as system class loader lock 1915 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1916 // Initialize basic classes 1917 resolve_well_known_classes(CHECK); 1918 } 1919 1920 // Compact table of directions on the initialization of klasses: 1921 static const short wk_init_info[] = { 1922 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1923 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1924 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1925 | (int)SystemDictionary::option ), 1926 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1927 #undef WK_KLASS_INIT_INFO 1928 0 1929 }; 1930 1931 #ifdef ASSERT 1932 bool SystemDictionary::is_well_known_klass(Symbol* class_name) { 1933 int sid; 1934 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) { 1935 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1936 if (class_name == symbol) { 1937 return true; 1938 } 1939 } 1940 return false; 1941 } 1942 #endif 1943 1944 bool SystemDictionary::resolve_wk_klass(WKID id, int init_opt, TRAPS) { 1945 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1946 int info = wk_init_info[id - FIRST_WKID]; 1947 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1948 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1949 InstanceKlass** klassp = &_well_known_klasses[id]; 1950 1951 bool must_load; 1952 #if INCLUDE_JVMCI 1953 if (EnableJVMCI) { 1954 // If JVMCI is enabled we require its classes to be found. 1955 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 1956 } else 1957 #endif 1958 { 1959 must_load = (init_opt < SystemDictionary::Opt); 1960 } 1961 1962 if ((*klassp) == NULL) { 1963 Klass* k; 1964 if (must_load) { 1965 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 1966 } else { 1967 k = resolve_or_null(symbol, CHECK_0); // load optional klass 1968 } 1969 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 1970 } 1971 return ((*klassp) != NULL); 1972 } 1973 1974 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1975 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1976 for (int id = (int)start_id; id < (int)limit_id; id++) { 1977 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1978 int info = wk_init_info[id - FIRST_WKID]; 1979 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1980 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1981 1982 resolve_wk_klass((WKID)id, opt, CHECK); 1983 } 1984 1985 // move the starting value forward to the limit: 1986 start_id = limit_id; 1987 } 1988 1989 void SystemDictionary::resolve_well_known_classes(TRAPS) { 1990 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once"); 1991 1992 // Create the ModuleEntry for java.base. This call needs to be done here, 1993 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 1994 ClassLoader::classLoader_init2(CHECK); 1995 1996 // Preload commonly used klasses 1997 WKID scan = FIRST_WKID; 1998 // first do Object, then String, Class 1999 #if INCLUDE_CDS 2000 if (UseSharedSpaces) { 2001 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2002 // Initialize the constant pool for the Object_class 2003 Object_klass()->constants()->restore_unshareable_info(CHECK); 2004 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2005 } else 2006 #endif 2007 { 2008 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2009 } 2010 2011 // Calculate offsets for String and Class classes since they are loaded and 2012 // can be used after this point. 2013 java_lang_String::compute_offsets(); 2014 java_lang_Class::compute_offsets(); 2015 2016 // Fixup mirrors for classes loaded before java.lang.Class. 2017 // These calls iterate over the objects currently in the perm gen 2018 // so calling them at this point is matters (not before when there 2019 // are fewer objects and not later after there are more objects 2020 // in the perm gen. 2021 Universe::initialize_basic_type_mirrors(CHECK); 2022 Universe::fixup_mirrors(CHECK); 2023 2024 // do a bunch more: 2025 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2026 2027 // Preload ref klasses and set reference types 2028 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2029 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2030 2031 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2032 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2033 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2034 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2035 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2036 2037 // JSR 292 classes 2038 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2039 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2040 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK); 2041 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK); 2042 WKID last = NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID); 2043 resolve_wk_klasses_until(last, scan, CHECK); 2044 2045 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2046 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2047 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2048 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2049 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2050 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2051 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2052 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2053 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2054 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2055 2056 { // Compute whether we should use checkPackageAccess or NOT 2057 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2058 _has_checkPackageAccess = (method != NULL); 2059 } 2060 2061 #ifdef ASSERT 2062 if (UseSharedSpaces) { 2063 assert(JvmtiExport::is_early_phase(), 2064 "All well known classes must be resolved in JVMTI early phase"); 2065 for (int i = FIRST_WKID; i < last; i++) { 2066 InstanceKlass* k = _well_known_klasses[i]; 2067 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook"); 2068 } 2069 } 2070 #endif 2071 } 2072 2073 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2074 // If so, returns the basic type it holds. If not, returns T_OBJECT. 2075 BasicType SystemDictionary::box_klass_type(Klass* k) { 2076 assert(k != NULL, ""); 2077 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2078 if (_box_klasses[i] == k) 2079 return (BasicType)i; 2080 } 2081 return T_OBJECT; 2082 } 2083 2084 // Constraints on class loaders. The details of the algorithm can be 2085 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2086 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2087 // that the dictionary needs to maintain a set of contraints that 2088 // must be satisfied by all classes in the dictionary. 2089 // if defining is true, then LinkageError if already in dictionary 2090 // if initiating loader, then ok if InstanceKlass matches existing entry 2091 2092 void SystemDictionary::check_constraints(unsigned int d_hash, 2093 InstanceKlass* k, 2094 Handle class_loader, 2095 bool defining, 2096 TRAPS) { 2097 ResourceMark rm(THREAD); 2098 stringStream ss; 2099 bool throwException = false; 2100 2101 { 2102 Symbol *name = k->name(); 2103 ClassLoaderData *loader_data = class_loader_data(class_loader); 2104 2105 MutexLocker mu(SystemDictionary_lock, THREAD); 2106 2107 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); 2108 if (check != NULL) { 2109 // If different InstanceKlass - duplicate class definition, 2110 // else - ok, class loaded by a different thread in parallel. 2111 // We should only have found it if it was done loading and ok to use. 2112 // The dictionary only holds instance classes, placeholders 2113 // also hold array classes. 2114 2115 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2116 if ((defining == true) || (k != check)) { 2117 throwException = true; 2118 ss.print("loader %s", loader_data->loader_name_and_id()); 2119 ss.print(" attempted duplicate %s definition for %s. (%s)", 2120 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true)); 2121 } else { 2122 return; 2123 } 2124 } 2125 2126 #ifdef ASSERT 2127 Symbol* ph_check = find_placeholder(name, loader_data); 2128 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2129 #endif 2130 2131 if (throwException == false) { 2132 if (constraints()->check_or_update(k, class_loader, name) == false) { 2133 throwException = true; 2134 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id()); 2135 ss.print(" wants to load %s %s.", 2136 k->external_kind(), k->external_name()); 2137 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); 2138 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) { 2139 ss.print(" A different %s with the same name was previously loaded by %s. (%s)", 2140 existing_klass->external_kind(), 2141 existing_klass->class_loader_data()->loader_name_and_id(), 2142 existing_klass->class_in_module_of_loader(false, true)); 2143 } else { 2144 ss.print(" (%s)", k->class_in_module_of_loader(false, true)); 2145 } 2146 } 2147 } 2148 } 2149 2150 // Throw error now if needed (cannot throw while holding 2151 // SystemDictionary_lock because of rank ordering) 2152 if (throwException == true) { 2153 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); 2154 } 2155 } 2156 2157 // Update class loader data dictionary - done after check_constraint and add_to_hierachy 2158 // have been called. 2159 void SystemDictionary::update_dictionary(unsigned int d_hash, 2160 int p_index, unsigned int p_hash, 2161 InstanceKlass* k, 2162 Handle class_loader, 2163 TRAPS) { 2164 // Compile_lock prevents systemDictionary updates during compilations 2165 assert_locked_or_safepoint(Compile_lock); 2166 Symbol* name = k->name(); 2167 ClassLoaderData *loader_data = class_loader_data(class_loader); 2168 2169 { 2170 MutexLocker mu1(SystemDictionary_lock, THREAD); 2171 2172 // See whether biased locking is enabled and if so set it for this 2173 // klass. 2174 // Note that this must be done past the last potential blocking 2175 // point / safepoint. We enable biased locking lazily using a 2176 // VM_Operation to iterate the SystemDictionary and installing the 2177 // biasable mark word into each InstanceKlass's prototype header. 2178 // To avoid race conditions where we accidentally miss enabling the 2179 // optimization for one class in the process of being added to the 2180 // dictionary, we must not safepoint after the test of 2181 // BiasedLocking::enabled(). 2182 if (UseBiasedLocking && BiasedLocking::enabled()) { 2183 // Set biased locking bit for all loaded classes; it will be 2184 // cleared if revocation occurs too often for this type 2185 // NOTE that we must only do this when the class is initally 2186 // defined, not each time it is referenced from a new class loader 2187 if (oopDesc::equals(k->class_loader(), class_loader())) { 2188 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2189 } 2190 } 2191 2192 // Make a new dictionary entry. 2193 Dictionary* dictionary = loader_data->dictionary(); 2194 InstanceKlass* sd_check = find_class(d_hash, name, dictionary); 2195 if (sd_check == NULL) { 2196 dictionary->add_klass(d_hash, name, k); 2197 2198 notice_modification(); 2199 } 2200 #ifdef ASSERT 2201 sd_check = find_class(d_hash, name, dictionary); 2202 assert (sd_check != NULL, "should have entry in dictionary"); 2203 // Note: there may be a placeholder entry: for circularity testing 2204 // or for parallel defines 2205 #endif 2206 SystemDictionary_lock->notify_all(); 2207 } 2208 } 2209 2210 2211 // Try to find a class name using the loader constraints. The 2212 // loader constraints might know about a class that isn't fully loaded 2213 // yet and these will be ignored. 2214 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2215 Symbol* class_name, Handle class_loader, TRAPS) { 2216 2217 // First see if it has been loaded directly. 2218 // Force the protection domain to be null. (This removes protection checks.) 2219 Handle no_protection_domain; 2220 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2221 no_protection_domain, CHECK_NULL); 2222 if (klass != NULL) 2223 return klass; 2224 2225 // Now look to see if it has been loaded elsewhere, and is subject to 2226 // a loader constraint that would require this loader to return the 2227 // klass that is already loaded. 2228 if (FieldType::is_array(class_name)) { 2229 // For array classes, their Klass*s are not kept in the 2230 // constraint table. The element Klass*s are. 2231 FieldArrayInfo fd; 2232 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2233 if (t != T_OBJECT) { 2234 klass = Universe::typeArrayKlassObj(t); 2235 } else { 2236 MutexLocker mu(SystemDictionary_lock, THREAD); 2237 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2238 } 2239 // If element class already loaded, allocate array klass 2240 if (klass != NULL) { 2241 klass = klass->array_klass_or_null(fd.dimension()); 2242 } 2243 } else { 2244 MutexLocker mu(SystemDictionary_lock, THREAD); 2245 // Non-array classes are easy: simply check the constraint table. 2246 klass = constraints()->find_constrained_klass(class_name, class_loader); 2247 } 2248 2249 return klass; 2250 } 2251 2252 2253 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2254 Handle class_loader1, 2255 Handle class_loader2, 2256 Thread* THREAD) { 2257 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2258 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2259 2260 Symbol* constraint_name = NULL; 2261 if (!FieldType::is_array(class_name)) { 2262 constraint_name = class_name; 2263 } else { 2264 // For array classes, their Klass*s are not kept in the 2265 // constraint table. The element classes are. 2266 FieldArrayInfo fd; 2267 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2268 // primitive types always pass 2269 if (t != T_OBJECT) { 2270 return true; 2271 } else { 2272 constraint_name = fd.object_key(); 2273 } 2274 } 2275 2276 Dictionary* dictionary1 = loader_data1->dictionary(); 2277 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); 2278 2279 Dictionary* dictionary2 = loader_data2->dictionary(); 2280 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); 2281 2282 { 2283 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2284 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); 2285 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); 2286 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2287 klass2, class_loader2); 2288 } 2289 } 2290 2291 // Add entry to resolution error table to record the error when the first 2292 // attempt to resolve a reference to a class has failed. 2293 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2294 Symbol* error, Symbol* message) { 2295 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2296 int index = resolution_errors()->hash_to_index(hash); 2297 { 2298 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2299 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2300 } 2301 } 2302 2303 // Delete a resolution error for RedefineClasses for a constant pool is going away 2304 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2305 resolution_errors()->delete_entry(pool); 2306 } 2307 2308 // Lookup resolution error table. Returns error if found, otherwise NULL. 2309 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2310 Symbol** message) { 2311 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2312 int index = resolution_errors()->hash_to_index(hash); 2313 { 2314 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2315 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2316 if (entry != NULL) { 2317 *message = entry->message(); 2318 return entry->error(); 2319 } else { 2320 return NULL; 2321 } 2322 } 2323 } 2324 2325 2326 // Signature constraints ensure that callers and callees agree about 2327 // the meaning of type names in their signatures. This routine is the 2328 // intake for constraints. It collects them from several places: 2329 // 2330 // * LinkResolver::resolve_method (if check_access is true) requires 2331 // that the resolving class (the caller) and the defining class of 2332 // the resolved method (the callee) agree on each type in the 2333 // method's signature. 2334 // 2335 // * LinkResolver::resolve_interface_method performs exactly the same 2336 // checks. 2337 // 2338 // * LinkResolver::resolve_field requires that the constant pool 2339 // attempting to link to a field agree with the field's defining 2340 // class about the type of the field signature. 2341 // 2342 // * klassVtable::initialize_vtable requires that, when a class 2343 // overrides a vtable entry allocated by a superclass, that the 2344 // overriding method (i.e., the callee) agree with the superclass 2345 // on each type in the method's signature. 2346 // 2347 // * klassItable::initialize_itable requires that, when a class fills 2348 // in its itables, for each non-abstract method installed in an 2349 // itable, the method (i.e., the callee) agree with the interface 2350 // on each type in the method's signature. 2351 // 2352 // All those methods have a boolean (check_access, checkconstraints) 2353 // which turns off the checks. This is used from specialized contexts 2354 // such as bootstrapping, dumping, and debugging. 2355 // 2356 // No direct constraint is placed between the class and its 2357 // supertypes. Constraints are only placed along linked relations 2358 // between callers and callees. When a method overrides or implements 2359 // an abstract method in a supertype (superclass or interface), the 2360 // constraints are placed as if the supertype were the caller to the 2361 // overriding method. (This works well, since callers to the 2362 // supertype have already established agreement between themselves and 2363 // the supertype.) As a result of all this, a class can disagree with 2364 // its supertype about the meaning of a type name, as long as that 2365 // class neither calls a relevant method of the supertype, nor is 2366 // called (perhaps via an override) from the supertype. 2367 // 2368 // 2369 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2370 // 2371 // Make sure all class components (including arrays) in the given 2372 // signature will be resolved to the same class in both loaders. 2373 // Returns the name of the type that failed a loader constraint check, or 2374 // NULL if no constraint failed. No exception except OOME is thrown. 2375 // Arrays are not added to the loader constraint table, their elements are. 2376 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2377 Handle loader1, Handle loader2, 2378 bool is_method, TRAPS) { 2379 // Nothing to do if loaders are the same. 2380 if (oopDesc::equals(loader1(), loader2())) { 2381 return NULL; 2382 } 2383 2384 SignatureStream sig_strm(signature, is_method); 2385 while (!sig_strm.is_done()) { 2386 if (sig_strm.is_object()) { 2387 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2388 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2389 return sig; 2390 } 2391 } 2392 sig_strm.next(); 2393 } 2394 return NULL; 2395 } 2396 2397 2398 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2399 Symbol* signature, 2400 TRAPS) { 2401 methodHandle empty; 2402 assert(MethodHandles::is_signature_polymorphic(iid) && 2403 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2404 iid != vmIntrinsics::_invokeGeneric, 2405 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2406 2407 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2408 int index = invoke_method_table()->hash_to_index(hash); 2409 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2410 methodHandle m; 2411 if (spe == NULL || spe->method() == NULL) { 2412 spe = NULL; 2413 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2414 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2415 if (!Arguments::is_interpreter_only()) { 2416 // Generate a compiled form of the MH intrinsic. 2417 AdapterHandlerLibrary::create_native_wrapper(m); 2418 // Check if have the compiled code. 2419 if (!m->has_compiled_code()) { 2420 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2421 "Out of space in CodeCache for method handle intrinsic", empty); 2422 } 2423 } 2424 // Now grab the lock. We might have to throw away the new method, 2425 // if a racing thread has managed to install one at the same time. 2426 { 2427 MutexLocker ml(SystemDictionary_lock, THREAD); 2428 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2429 if (spe == NULL) 2430 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2431 if (spe->method() == NULL) 2432 spe->set_method(m()); 2433 } 2434 } 2435 2436 assert(spe != NULL && spe->method() != NULL, ""); 2437 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2438 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2439 "MH intrinsic invariant"); 2440 return spe->method(); 2441 } 2442 2443 // Helper for unpacking the return value from linkMethod and linkCallSite. 2444 static methodHandle unpack_method_and_appendix(Handle mname, 2445 Klass* accessing_klass, 2446 objArrayHandle appendix_box, 2447 Handle* appendix_result, 2448 TRAPS) { 2449 methodHandle empty; 2450 if (mname.not_null()) { 2451 Method* m = java_lang_invoke_MemberName::vmtarget(mname()); 2452 if (m != NULL) { 2453 oop appendix = appendix_box->obj_at(0); 2454 if (TraceMethodHandles) { 2455 #ifndef PRODUCT 2456 ttyLocker ttyl; 2457 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2458 m->print(); 2459 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2460 tty->cr(); 2461 #endif //PRODUCT 2462 } 2463 (*appendix_result) = Handle(THREAD, appendix); 2464 // the target is stored in the cpCache and if a reference to this 2465 // MemberName is dropped we need a way to make sure the 2466 // class_loader containing this method is kept alive. 2467 ClassLoaderData* this_key = accessing_klass->class_loader_data(); 2468 this_key->record_dependency(m->method_holder()); 2469 return methodHandle(THREAD, m); 2470 } 2471 } 2472 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2473 return empty; 2474 } 2475 2476 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, 2477 Symbol* name, 2478 Symbol* signature, 2479 Klass* accessing_klass, 2480 Handle *appendix_result, 2481 Handle *method_type_result, 2482 TRAPS) { 2483 methodHandle empty; 2484 assert(THREAD->can_call_java() ,""); 2485 Handle method_type = 2486 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2487 2488 int ref_kind = JVM_REF_invokeVirtual; 2489 oop name_oop = StringTable::intern(name, CHECK_(empty)); 2490 Handle name_str (THREAD, name_oop); 2491 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2492 assert(appendix_box->obj_at(0) == NULL, ""); 2493 2494 // This should not happen. JDK code should take care of that. 2495 if (accessing_klass == NULL || method_type.is_null()) { 2496 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2497 } 2498 2499 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2500 JavaCallArguments args; 2501 args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); 2502 args.push_int(ref_kind); 2503 args.push_oop(Handle(THREAD, klass->java_mirror())); 2504 args.push_oop(name_str); 2505 args.push_oop(method_type); 2506 args.push_oop(appendix_box); 2507 JavaValue result(T_OBJECT); 2508 JavaCalls::call_static(&result, 2509 SystemDictionary::MethodHandleNatives_klass(), 2510 vmSymbols::linkMethod_name(), 2511 vmSymbols::linkMethod_signature(), 2512 &args, CHECK_(empty)); 2513 Handle mname(THREAD, (oop) result.get_jobject()); 2514 (*method_type_result) = method_type; 2515 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2516 } 2517 2518 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2519 // We must ensure that all class loaders everywhere will reach this class, for any client. 2520 // This is a safe bet for public classes in java.lang, such as Object and String. 2521 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2522 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2523 static bool is_always_visible_class(oop mirror) { 2524 Klass* klass = java_lang_Class::as_Klass(mirror); 2525 if (klass->is_objArray_klass()) { 2526 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2527 } 2528 if (klass->is_typeArray_klass()) { 2529 return true; // primitive array 2530 } 2531 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2532 return klass->is_public() && 2533 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2534 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2535 } 2536 2537 2538 // Return the Java mirror (java.lang.Class instance) for a single-character 2539 // descriptor. This result, when available, is the same as produced by the 2540 // heavier API point of the same name that takes a Symbol. 2541 oop SystemDictionary::find_java_mirror_for_type(char signature_char) { 2542 return java_lang_Class::primitive_mirror(char2type(signature_char)); 2543 } 2544 2545 // Find or construct the Java mirror (java.lang.Class instance) for a 2546 // for the given field type signature, as interpreted relative to the 2547 // given class loader. Handles primitives, void, references, arrays, 2548 // and all other reflectable types, except method types. 2549 // N.B. Code in reflection should use this entry point. 2550 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, 2551 Klass* accessing_klass, 2552 Handle class_loader, 2553 Handle protection_domain, 2554 SignatureStream::FailureMode failure_mode, 2555 TRAPS) { 2556 Handle empty; 2557 2558 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), 2559 "one or the other, or perhaps neither"); 2560 2561 Symbol* type = signature; 2562 2563 // What we have here must be a valid field descriptor, 2564 // and all valid field descriptors are supported. 2565 // Produce the same java.lang.Class that reflection reports. 2566 if (type->utf8_length() == 1) { 2567 2568 // It's a primitive. (Void has a primitive mirror too.) 2569 char ch = (char) type->byte_at(0); 2570 assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); 2571 return Handle(THREAD, find_java_mirror_for_type(ch)); 2572 2573 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { 2574 2575 // It's a reference type. 2576 if (accessing_klass != NULL) { 2577 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2578 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2579 } 2580 Klass* constant_type_klass; 2581 if (failure_mode == SignatureStream::ReturnNull) { 2582 constant_type_klass = resolve_or_null(type, class_loader, protection_domain, 2583 CHECK_(empty)); 2584 } else { 2585 bool throw_error = (failure_mode == SignatureStream::NCDFError); 2586 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, 2587 throw_error, CHECK_(empty)); 2588 } 2589 if (constant_type_klass == NULL) { 2590 return Handle(); // report failure this way 2591 } 2592 Handle mirror(THREAD, constant_type_klass->java_mirror()); 2593 2594 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. 2595 if (accessing_klass != NULL) { 2596 Klass* sel_klass = constant_type_klass; 2597 bool fold_type_to_class = true; 2598 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2599 fold_type_to_class, CHECK_(empty)); 2600 } 2601 2602 return mirror; 2603 2604 } 2605 2606 // Fall through to an error. 2607 assert(false, "unsupported mirror syntax"); 2608 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); 2609 } 2610 2611 2612 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2613 // signature, as interpreted relative to the given class loader. 2614 // Because of class loader constraints, all method handle usage must be 2615 // consistent with this loader. 2616 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2617 Klass* accessing_klass, 2618 TRAPS) { 2619 Handle empty; 2620 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2621 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2622 int index = invoke_method_table()->hash_to_index(hash); 2623 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2624 if (spe != NULL && spe->method_type() != NULL) { 2625 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2626 return Handle(THREAD, spe->method_type()); 2627 } else if (!THREAD->can_call_java()) { 2628 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2629 return Handle(); // do not attempt from within compiler, unless it was cached 2630 } 2631 2632 Handle class_loader, protection_domain; 2633 if (accessing_klass != NULL) { 2634 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2635 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2636 } 2637 bool can_be_cached = true; 2638 int npts = ArgumentCount(signature).size(); 2639 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2640 int arg = 0; 2641 Handle rt; // the return type from the signature 2642 ResourceMark rm(THREAD); 2643 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2644 oop mirror = NULL; 2645 if (can_be_cached) { 2646 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2647 mirror = ss.as_java_mirror(Handle(), Handle(), 2648 SignatureStream::ReturnNull, CHECK_(empty)); 2649 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2650 // Fall back to accessing_klass context. 2651 can_be_cached = false; 2652 } 2653 } 2654 if (!can_be_cached) { 2655 // Resolve, throwing a real error if it doesn't work. 2656 mirror = ss.as_java_mirror(class_loader, protection_domain, 2657 SignatureStream::NCDFError, CHECK_(empty)); 2658 } 2659 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string()); 2660 if (ss.at_return_type()) 2661 rt = Handle(THREAD, mirror); 2662 else 2663 pts->obj_at_put(arg++, mirror); 2664 2665 // Check accessibility. 2666 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { 2667 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2668 mirror = NULL; // safety 2669 // Emulate ConstantPool::verify_constant_pool_resolve. 2670 bool fold_type_to_class = true; 2671 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, 2672 fold_type_to_class, CHECK_(empty)); 2673 } 2674 } 2675 assert(arg == npts, ""); 2676 2677 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType 2678 JavaCallArguments args(Handle(THREAD, rt())); 2679 args.push_oop(pts); 2680 JavaValue result(T_OBJECT); 2681 JavaCalls::call_static(&result, 2682 SystemDictionary::MethodHandleNatives_klass(), 2683 vmSymbols::findMethodHandleType_name(), 2684 vmSymbols::findMethodHandleType_signature(), 2685 &args, CHECK_(empty)); 2686 Handle method_type(THREAD, (oop) result.get_jobject()); 2687 2688 if (can_be_cached) { 2689 // We can cache this MethodType inside the JVM. 2690 MutexLocker ml(SystemDictionary_lock, THREAD); 2691 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2692 if (spe == NULL) 2693 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2694 if (spe->method_type() == NULL) { 2695 spe->set_method_type(method_type()); 2696 } 2697 } 2698 2699 // report back to the caller with the MethodType 2700 return method_type; 2701 } 2702 2703 Handle SystemDictionary::find_field_handle_type(Symbol* signature, 2704 Klass* accessing_klass, 2705 TRAPS) { 2706 Handle empty; 2707 ResourceMark rm(THREAD); 2708 SignatureStream ss(signature, /*is_method=*/ false); 2709 if (!ss.is_done()) { 2710 Handle class_loader, protection_domain; 2711 if (accessing_klass != NULL) { 2712 class_loader = Handle(THREAD, accessing_klass->class_loader()); 2713 protection_domain = Handle(THREAD, accessing_klass->protection_domain()); 2714 } 2715 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); 2716 ss.next(); 2717 if (ss.is_done()) { 2718 return Handle(THREAD, mirror); 2719 } 2720 } 2721 return empty; 2722 } 2723 2724 // Ask Java code to find or construct a method handle constant. 2725 Handle SystemDictionary::link_method_handle_constant(Klass* caller, 2726 int ref_kind, //e.g., JVM_REF_invokeVirtual 2727 Klass* callee, 2728 Symbol* name, 2729 Symbol* signature, 2730 TRAPS) { 2731 Handle empty; 2732 if (caller == NULL) { 2733 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2734 } 2735 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2736 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2737 2738 // Put symbolic info from the MH constant into freshly created MemberName and resolve it. 2739 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); 2740 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); 2741 java_lang_invoke_MemberName::set_name (mname(), name_str()); 2742 java_lang_invoke_MemberName::set_type (mname(), signature_str()); 2743 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); 2744 2745 if (ref_kind == JVM_REF_invokeVirtual && 2746 MethodHandles::is_signature_polymorphic_public_name(callee, name)) { 2747 // Skip resolution for public signature polymorphic methods such as 2748 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle 2749 // They require appendix argument which MemberName resolution doesn't handle. 2750 // There's special logic on JDK side to handle them 2751 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). 2752 } else { 2753 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); 2754 } 2755 2756 // After method/field resolution succeeded, it's safe to resolve MH signature as well. 2757 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); 2758 2759 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2760 JavaCallArguments args; 2761 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class 2762 args.push_int(ref_kind); 2763 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class 2764 args.push_oop(name_str); 2765 args.push_oop(type); 2766 JavaValue result(T_OBJECT); 2767 JavaCalls::call_static(&result, 2768 SystemDictionary::MethodHandleNatives_klass(), 2769 vmSymbols::linkMethodHandleConstant_name(), 2770 vmSymbols::linkMethodHandleConstant_signature(), 2771 &args, CHECK_(empty)); 2772 return Handle(THREAD, (oop) result.get_jobject()); 2773 } 2774 2775 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry 2776 Handle SystemDictionary::link_dynamic_constant(Klass* caller, 2777 int condy_index, 2778 Handle bootstrap_specifier, 2779 Symbol* name, 2780 Symbol* type, 2781 TRAPS) { 2782 Handle empty; 2783 Handle bsm, info; 2784 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2785 bsm = bootstrap_specifier; 2786 } else { 2787 assert(bootstrap_specifier->is_objArray(), ""); 2788 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2789 assert(args->length() == 2, ""); 2790 bsm = Handle(THREAD, args->obj_at(0)); 2791 info = Handle(THREAD, args->obj_at(1)); 2792 } 2793 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2794 "caller must supply a valid BSM"); 2795 2796 // This should not happen. JDK code should take care of that. 2797 if (caller == NULL) { 2798 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); 2799 } 2800 2801 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2802 2803 // Resolve the constant type in the context of the caller class 2804 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, 2805 CHECK_(empty)); 2806 2807 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) 2808 JavaCallArguments args; 2809 args.push_oop(Handle(THREAD, caller->java_mirror())); 2810 args.push_int(condy_index); 2811 args.push_oop(bsm); 2812 args.push_oop(constant_name); 2813 args.push_oop(type_mirror); 2814 args.push_oop(info); 2815 JavaValue result(T_OBJECT); 2816 JavaCalls::call_static(&result, 2817 SystemDictionary::MethodHandleNatives_klass(), 2818 vmSymbols::linkDynamicConstant_name(), 2819 vmSymbols::linkDynamicConstant_signature(), 2820 &args, CHECK_(empty)); 2821 2822 return Handle(THREAD, (oop) result.get_jobject()); 2823 } 2824 2825 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2826 // name and signature, as interpreted relative to the given class loader. 2827 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, 2828 int indy_index, 2829 Handle bootstrap_specifier, 2830 Symbol* name, 2831 Symbol* type, 2832 Handle *appendix_result, 2833 Handle *method_type_result, 2834 TRAPS) { 2835 methodHandle empty; 2836 Handle bsm, info; 2837 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2838 bsm = bootstrap_specifier; 2839 } else { 2840 objArrayOop args = (objArrayOop) bootstrap_specifier(); 2841 assert(args->length() == 2, ""); 2842 bsm = Handle(THREAD, args->obj_at(0)); 2843 info = Handle(THREAD, args->obj_at(1)); 2844 } 2845 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2846 "caller must supply a valid BSM"); 2847 2848 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2849 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2850 2851 // This should not happen. JDK code should take care of that. 2852 if (caller == NULL || method_type.is_null()) { 2853 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2854 } 2855 2856 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2857 assert(appendix_box->obj_at(0) == NULL, ""); 2858 2859 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) 2860 JavaCallArguments args; 2861 args.push_oop(Handle(THREAD, caller->java_mirror())); 2862 args.push_int(indy_index); 2863 args.push_oop(bsm); 2864 args.push_oop(method_name); 2865 args.push_oop(method_type); 2866 args.push_oop(info); 2867 args.push_oop(appendix_box); 2868 JavaValue result(T_OBJECT); 2869 JavaCalls::call_static(&result, 2870 SystemDictionary::MethodHandleNatives_klass(), 2871 vmSymbols::linkCallSite_name(), 2872 vmSymbols::linkCallSite_signature(), 2873 &args, CHECK_(empty)); 2874 Handle mname(THREAD, (oop) result.get_jobject()); 2875 (*method_type_result) = method_type; 2876 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2877 } 2878 2879 // Protection domain cache table handling 2880 2881 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { 2882 return _pd_cache_table->get(protection_domain); 2883 } 2884 2885 #if INCLUDE_CDS 2886 void SystemDictionary::reorder_dictionary_for_sharing() { 2887 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); 2888 } 2889 #endif 2890 2891 size_t SystemDictionary::count_bytes_for_buckets() { 2892 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); 2893 } 2894 2895 size_t SystemDictionary::count_bytes_for_table() { 2896 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); 2897 } 2898 2899 void SystemDictionary::copy_buckets(char* top, char* end) { 2900 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); 2901 } 2902 2903 void SystemDictionary::copy_table(char* top, char* end) { 2904 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); 2905 } 2906 2907 // ---------------------------------------------------------------------------- 2908 void SystemDictionary::print_shared(outputStream *st) { 2909 shared_dictionary()->print_on(st); 2910 } 2911 2912 void SystemDictionary::print_on(outputStream *st) { 2913 if (shared_dictionary() != NULL) { 2914 st->print_cr("Shared Dictionary"); 2915 shared_dictionary()->print_on(st); 2916 st->cr(); 2917 } 2918 2919 GCMutexLocker mu(SystemDictionary_lock); 2920 2921 ClassLoaderDataGraph::print_dictionary(st); 2922 2923 // Placeholders 2924 placeholders()->print_on(st); 2925 st->cr(); 2926 2927 // loader constraints - print under SD_lock 2928 constraints()->print_on(st); 2929 st->cr(); 2930 2931 _pd_cache_table->print_on(st); 2932 st->cr(); 2933 } 2934 2935 void SystemDictionary::verify() { 2936 guarantee(constraints() != NULL, 2937 "Verify of loader constraints failed"); 2938 guarantee(placeholders()->number_of_entries() >= 0, 2939 "Verify of placeholders failed"); 2940 2941 GCMutexLocker mu(SystemDictionary_lock); 2942 2943 // Verify dictionary 2944 ClassLoaderDataGraph::verify_dictionary(); 2945 2946 placeholders()->verify(); 2947 2948 // Verify constraint table 2949 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2950 constraints()->verify(placeholders()); 2951 2952 _pd_cache_table->verify(); 2953 } 2954 2955 void SystemDictionary::dump(outputStream *st, bool verbose) { 2956 assert_locked_or_safepoint(SystemDictionary_lock); 2957 if (verbose) { 2958 print_on(st); 2959 } else { 2960 if (shared_dictionary() != NULL) { 2961 shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); 2962 } 2963 ClassLoaderDataGraph::print_dictionary_statistics(st); 2964 placeholders()->print_table_statistics(st, "Placeholder Table"); 2965 constraints()->print_table_statistics(st, "LoaderConstraints Table"); 2966 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); 2967 } 2968 } 2969 2970 // Utility for dumping dictionaries. 2971 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : 2972 DCmdWithParser(output, heap), 2973 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", 2974 "BOOLEAN", false, "false") { 2975 _dcmdparser.add_dcmd_option(&_verbose); 2976 } 2977 2978 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { 2979 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, 2980 _verbose.value()); 2981 VMThread::execute(&dumper); 2982 } 2983 2984 int SystemDictionaryDCmd::num_arguments() { 2985 ResourceMark rm; 2986 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); 2987 if (dcmd != NULL) { 2988 DCmdMark mark(dcmd); 2989 return dcmd->_dcmdparser.num_arguments(); 2990 } else { 2991 return 0; 2992 } 2993 } 2994 2995 class CombineDictionariesClosure : public CLDClosure { 2996 private: 2997 Dictionary* _master_dictionary; 2998 public: 2999 CombineDictionariesClosure(Dictionary* master_dictionary) : 3000 _master_dictionary(master_dictionary) {} 3001 void do_cld(ClassLoaderData* cld) { 3002 ResourceMark rm; 3003 if (cld->is_anonymous()) { 3004 return; 3005 } 3006 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { 3007 for (int i = 0; i < cld->dictionary()->table_size(); ++i) { 3008 Dictionary* curr_dictionary = cld->dictionary(); 3009 DictionaryEntry* p = curr_dictionary->bucket(i); 3010 while (p != NULL) { 3011 Symbol* name = p->instance_klass()->name(); 3012 unsigned int d_hash = _master_dictionary->compute_hash(name); 3013 int d_index = _master_dictionary->hash_to_index(d_hash); 3014 DictionaryEntry* next = p->next(); 3015 if (p->literal()->class_loader_data() != cld) { 3016 // This is an initiating class loader entry; don't use it 3017 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); 3018 curr_dictionary->free_entry(p); 3019 } else { 3020 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); 3021 curr_dictionary->unlink_entry(p); 3022 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. 3023 _master_dictionary->add_entry(d_index, p); 3024 } 3025 p = next; 3026 } 3027 *curr_dictionary->bucket_addr(i) = NULL; 3028 } 3029 } 3030 } 3031 }; 3032 3033 // Combining platform and system loader dictionaries into boot loader dictionary. 3034 // During run time, we only have one shared dictionary. 3035 void SystemDictionary::combine_shared_dictionaries() { 3036 assert(DumpSharedSpaces, "dump time only"); 3037 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); 3038 CombineDictionariesClosure cdc(master_dictionary); 3039 ClassLoaderDataGraph::cld_do(&cdc); 3040 3041 // These tables are no longer valid or necessary. Keeping them around will 3042 // cause SystemDictionary::verify() to fail. Let's empty them. 3043 _placeholders = new PlaceholderTable(_placeholder_table_size); 3044 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 3045 3046 NOT_PRODUCT(SystemDictionary::verify()); 3047 } 3048 3049 void SystemDictionary::initialize_oop_storage() { 3050 _vm_weak_oop_storage = 3051 new OopStorage("VM Weak Oop Handles", 3052 VMWeakAlloc_lock, 3053 VMWeakActive_lock); 3054 } 3055 3056 OopStorage* SystemDictionary::vm_weak_oop_storage() { 3057 assert(_vm_weak_oop_storage != NULL, "Uninitialized"); 3058 return _vm_weak_oop_storage; 3059 }