systemDictionary.cpp revision 11650:047ad22e7be5
1/* 2 * Copyright (c) 1997, 2016, 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 "classfile/classFileParser.hpp" 27#include "classfile/classFileStream.hpp" 28#include "classfile/classLoader.hpp" 29#include "classfile/classLoaderData.inline.hpp" 30#include "classfile/classLoaderExt.hpp" 31#include "classfile/dictionary.hpp" 32#include "classfile/javaClasses.inline.hpp" 33#include "classfile/klassFactory.hpp" 34#include "classfile/loaderConstraints.hpp" 35#include "classfile/packageEntry.hpp" 36#include "classfile/placeholders.hpp" 37#include "classfile/resolutionErrors.hpp" 38#include "classfile/stringTable.hpp" 39#include "classfile/systemDictionary.hpp" 40#include "classfile/vmSymbols.hpp" 41#include "code/codeCache.hpp" 42#include "compiler/compileBroker.hpp" 43#include "gc/shared/gcLocker.hpp" 44#include "interpreter/bytecodeStream.hpp" 45#include "interpreter/interpreter.hpp" 46#include "memory/filemap.hpp" 47#include "memory/oopFactory.hpp" 48#include "memory/resourceArea.hpp" 49#include "oops/instanceKlass.hpp" 50#include "oops/instanceRefKlass.hpp" 51#include "oops/klass.inline.hpp" 52#include "oops/methodData.hpp" 53#include "oops/objArrayKlass.hpp" 54#include "oops/objArrayOop.inline.hpp" 55#include "oops/oop.inline.hpp" 56#include "oops/symbol.hpp" 57#include "oops/typeArrayKlass.hpp" 58#include "prims/jvmtiEnvBase.hpp" 59#include "prims/methodHandles.hpp" 60#include "runtime/arguments.hpp" 61#include "runtime/biasedLocking.hpp" 62#include "runtime/fieldType.hpp" 63#include "runtime/handles.inline.hpp" 64#include "runtime/java.hpp" 65#include "runtime/javaCalls.hpp" 66#include "runtime/mutexLocker.hpp" 67#include "runtime/orderAccess.inline.hpp" 68#include "runtime/signature.hpp" 69#include "services/classLoadingService.hpp" 70#include "services/threadService.hpp" 71#include "trace/traceMacros.hpp" 72#include "utilities/macros.hpp" 73#include "utilities/stringUtils.hpp" 74#include "utilities/ticks.hpp" 75#if INCLUDE_CDS 76#include "classfile/sharedClassUtil.hpp" 77#include "classfile/systemDictionaryShared.hpp" 78#endif 79#if INCLUDE_JVMCI 80#include "jvmci/jvmciRuntime.hpp" 81#endif 82#if INCLUDE_TRACE 83#include "trace/tracing.hpp" 84#endif 85 86Dictionary* SystemDictionary::_dictionary = NULL; 87PlaceholderTable* SystemDictionary::_placeholders = NULL; 88Dictionary* SystemDictionary::_shared_dictionary = NULL; 89LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 90ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 91SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 92 93 94int SystemDictionary::_number_of_modifications = 0; 95int SystemDictionary::_sdgeneration = 0; 96const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 97 20201,40423,99991}; 98 99oop SystemDictionary::_system_loader_lock_obj = NULL; 100 101InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 102 = { NULL /*, NULL...*/ }; 103 104InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 105 106oop SystemDictionary::_java_system_loader = NULL; 107 108bool SystemDictionary::_has_loadClassInternal = false; 109bool SystemDictionary::_has_checkPackageAccess = false; 110 111// lazily initialized klass variables 112InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 113 114 115// ---------------------------------------------------------------------------- 116// Java-level SystemLoader 117 118oop SystemDictionary::java_system_loader() { 119 return _java_system_loader; 120} 121 122void SystemDictionary::compute_java_system_loader(TRAPS) { 123 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 124 JavaValue result(T_OBJECT); 125 JavaCalls::call_static(&result, 126 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 127 vmSymbols::getSystemClassLoader_name(), 128 vmSymbols::void_classloader_signature(), 129 CHECK); 130 131 _java_system_loader = (oop)result.get_jobject(); 132 133 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) 134} 135 136 137ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 138 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 139 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD); 140} 141 142// ---------------------------------------------------------------------------- 143// debugging 144 145#ifdef ASSERT 146 147// return true if class_name contains no '.' (internal format is '/') 148bool SystemDictionary::is_internal_format(Symbol* class_name) { 149 if (class_name != NULL) { 150 ResourceMark rm; 151 char* name = class_name->as_C_string(); 152 return strchr(name, '.') == NULL; 153 } else { 154 return true; 155 } 156} 157 158#endif 159 160// ---------------------------------------------------------------------------- 161// Parallel class loading check 162 163bool SystemDictionary::is_parallelCapable(Handle class_loader) { 164 if (UnsyncloadClass || class_loader.is_null()) return true; 165 if (AlwaysLockClassLoader) return false; 166 return java_lang_ClassLoader::parallelCapable(class_loader()); 167} 168// ---------------------------------------------------------------------------- 169// ParallelDefineClass flag does not apply to bootclass loader 170bool SystemDictionary::is_parallelDefine(Handle class_loader) { 171 if (class_loader.is_null()) return false; 172 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 173 return true; 174 } 175 return false; 176} 177 178// Returns true if the passed class loader is the builtin application class loader 179// or a custom system class loader. A customer system class loader can be 180// specified via -Djava.system.class.loader. 181bool SystemDictionary::is_system_class_loader(Handle class_loader) { 182 if (class_loader.is_null()) { 183 return false; 184 } 185 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || 186 class_loader() == _java_system_loader); 187} 188 189// Returns true if the passed class loader is the platform class loader. 190bool SystemDictionary::is_platform_class_loader(Handle class_loader) { 191 if (class_loader.is_null()) { 192 return false; 193 } 194 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); 195} 196 197// ---------------------------------------------------------------------------- 198// Resolving of classes 199 200// Forwards to resolve_or_null 201 202Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 203 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 204 if (HAS_PENDING_EXCEPTION || klass == NULL) { 205 KlassHandle k_h(THREAD, klass); 206 // can return a null klass 207 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD); 208 } 209 return klass; 210} 211 212Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 213 bool throw_error, 214 KlassHandle klass_h, TRAPS) { 215 if (HAS_PENDING_EXCEPTION) { 216 // If we have a pending exception we forward it to the caller, unless throw_error is true, 217 // in which case we have to check whether the pending exception is a ClassNotFoundException, 218 // and if so convert it to a NoClassDefFoundError 219 // And chain the original ClassNotFoundException 220 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 221 ResourceMark rm(THREAD); 222 assert(klass_h() == NULL, "Should not have result with exception pending"); 223 Handle e(THREAD, PENDING_EXCEPTION); 224 CLEAR_PENDING_EXCEPTION; 225 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 226 } else { 227 return NULL; 228 } 229 } 230 // Class not found, throw appropriate error or exception depending on value of throw_error 231 if (klass_h() == NULL) { 232 ResourceMark rm(THREAD); 233 if (throw_error) { 234 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 235 } else { 236 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 237 } 238 } 239 return (Klass*)klass_h(); 240} 241 242 243Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 244 bool throw_error, TRAPS) 245{ 246 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 247} 248 249 250// Forwards to resolve_instance_class_or_null 251 252Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 253 assert(THREAD->can_call_java(), 254 "can not load classes with compiler thread: class=%s, classloader=%s", 255 class_name->as_C_string(), 256 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); 257 if (FieldType::is_array(class_name)) { 258 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); 259 } else if (FieldType::is_obj(class_name)) { 260 ResourceMark rm(THREAD); 261 // Ignore wrapping L and ;. 262 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 263 class_name->utf8_length() - 2, CHECK_NULL); 264 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); 265 } else { 266 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); 267 } 268} 269 270Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 271 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 272} 273 274// Forwards to resolve_instance_class_or_null 275 276Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 277 Handle class_loader, 278 Handle protection_domain, 279 TRAPS) { 280 assert(FieldType::is_array(class_name), "must be array"); 281 Klass* k = NULL; 282 FieldArrayInfo fd; 283 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 284 // of this call 285 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 286 if (t == T_OBJECT) { 287 // naked oop "k" is OK here -- we assign back into it 288 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 289 class_loader, 290 protection_domain, 291 CHECK_NULL); 292 if (k != NULL) { 293 k = k->array_klass(fd.dimension(), CHECK_NULL); 294 } 295 } else { 296 k = Universe::typeArrayKlassObj(t); 297 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 298 } 299 return k; 300} 301 302 303// Must be called for any super-class or super-interface resolution 304// during class definition to allow class circularity checking 305// super-interface callers: 306// parse_interfaces - for defineClass & jvmtiRedefineClasses 307// super-class callers: 308// ClassFileParser - for defineClass & jvmtiRedefineClasses 309// load_shared_class - while loading a class from shared archive 310// resolve_instance_class_or_null: 311// via: handle_parallel_super_load 312// when resolving a class that has an existing placeholder with 313// a saved superclass [i.e. a defineClass is currently in progress] 314// if another thread is trying to resolve the class, it must do 315// super-class checks on its own thread to catch class circularity 316// This last call is critical in class circularity checking for cases 317// where classloading is delegated to different threads and the 318// classloader lock is released. 319// Take the case: Base->Super->Base 320// 1. If thread T1 tries to do a defineClass of class Base 321// resolve_super_or_fail creates placeholder: T1, Base (super Super) 322// 2. resolve_instance_class_or_null does not find SD or placeholder for Super 323// so it tries to load Super 324// 3. If we load the class internally, or user classloader uses same thread 325// loadClassFromxxx or defineClass via parseClassFile Super ... 326// 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 327// 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 328// 3.4 calls resolve_super_or_fail Base 329// 3.5 finds T1,Base -> throws class circularity 330//OR 4. If T2 tries to resolve Super via defineClass Super ... 331// 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 332// 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 333// 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 334// 4.4 finds T2, Super -> throws class circularity 335// Must be called, even if superclass is null, since this is 336// where the placeholder entry is created which claims this 337// thread is loading this class/classloader. 338Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 339 Symbol* class_name, 340 Handle class_loader, 341 Handle protection_domain, 342 bool is_superclass, 343 TRAPS) { 344#if INCLUDE_CDS 345 if (DumpSharedSpaces) { 346 // Special processing for CDS dump time. 347 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, 348 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); 349 if (k) { 350 return k; 351 } 352 } 353#endif // INCLUDE_CDS 354 355 // Double-check, if child class is already loaded, just return super-class,interface 356 // Don't add a placedholder if already loaded, i.e. already in system dictionary 357 // Make sure there's a placeholder for the *child* before resolving. 358 // Used as a claim that this thread is currently loading superclass/classloader 359 // Used here for ClassCircularity checks and also for heap verification 360 // (every InstanceKlass in the heap needs to be in the system dictionary 361 // or have a placeholder). 362 // Must check ClassCircularity before checking if super class is already loaded 363 // 364 // We might not already have a placeholder if this child_name was 365 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 366 // the name of the class might not be known until the stream is actually 367 // parsed. 368 // Bugs 4643874, 4715493 369 // compute_hash can have a safepoint 370 371 ClassLoaderData* loader_data = class_loader_data(class_loader); 372 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 373 int d_index = dictionary()->hash_to_index(d_hash); 374 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 375 int p_index = placeholders()->hash_to_index(p_hash); 376 // can't throw error holding a lock 377 bool child_already_loaded = false; 378 bool throw_circularity_error = false; 379 { 380 MutexLocker mu(SystemDictionary_lock, THREAD); 381 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 382 Klass* quicksuperk; 383 // to support // loading: if child done loading, just return superclass 384 // if class_name, & class_loader don't match: 385 // if initial define, SD update will give LinkageError 386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 387 // so we don't throw an exception here. 388 // see: nsk redefclass014 & java.lang.instrument Instrument032 389 if ((childk != NULL ) && (is_superclass) && 390 ((quicksuperk = childk->super()) != NULL) && 391 392 ((quicksuperk->name() == class_name) && 393 (quicksuperk->class_loader() == class_loader()))) { 394 return quicksuperk; 395 } else { 396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 398 throw_circularity_error = true; 399 } 400 } 401 if (!throw_circularity_error) { 402 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 403 } 404 } 405 if (throw_circularity_error) { 406 ResourceMark rm(THREAD); 407 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 408 } 409 410// java.lang.Object should have been found above 411 assert(class_name != NULL, "null super class for resolving"); 412 // Resolve the super class or interface, check results on return 413 Klass* superk = SystemDictionary::resolve_or_null(class_name, 414 class_loader, 415 protection_domain, 416 THREAD); 417 418 KlassHandle superk_h(THREAD, superk); 419 420 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 421 // It is no longer necessary to keep the placeholder table alive until update_dictionary 422 // or error. GC used to walk the placeholder table as strong roots. 423 // The instanceKlass is kept alive because the class loader is on the stack, 424 // which keeps the loader_data alive, as well as all instanceKlasses in 425 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 426 { 427 MutexLocker mu(SystemDictionary_lock, THREAD); 428 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 429 SystemDictionary_lock->notify_all(); 430 } 431 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 432 // can null superk 433 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD)); 434 } 435 436 return superk_h(); 437} 438 439void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 440 Handle class_loader, 441 Handle protection_domain, 442 TRAPS) { 443 if(!has_checkPackageAccess()) return; 444 445 // Now we have to call back to java to check if the initating class has access 446 JavaValue result(T_VOID); 447 if (log_is_enabled(Debug, protectiondomain)) { 448 ResourceMark rm; 449 // Print out trace information 450 outputStream* log = Log(protectiondomain)::debug_stream(); 451 log->print_cr("Checking package access"); 452 log->print("class loader: "); class_loader()->print_value_on(log); 453 log->print(" protection domain: "); protection_domain()->print_value_on(log); 454 log->print(" loading: "); klass()->print_value_on(log); 455 log->cr(); 456 } 457 458 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 459 JavaCalls::call_special(&result, 460 class_loader, 461 system_loader, 462 vmSymbols::checkPackageAccess_name(), 463 vmSymbols::class_protectiondomain_signature(), 464 Handle(THREAD, klass->java_mirror()), 465 protection_domain, 466 THREAD); 467 468 if (HAS_PENDING_EXCEPTION) { 469 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); 470 } else { 471 log_debug(protectiondomain)("granted"); 472 } 473 474 if (HAS_PENDING_EXCEPTION) return; 475 476 // If no exception has been thrown, we have validated the protection domain 477 // Insert the protection domain of the initiating class into the set. 478 { 479 // We recalculate the entry here -- we've called out to java since 480 // the last time it was calculated. 481 ClassLoaderData* loader_data = class_loader_data(class_loader); 482 483 Symbol* kn = klass->name(); 484 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 485 int d_index = dictionary()->hash_to_index(d_hash); 486 487 MutexLocker mu(SystemDictionary_lock, THREAD); 488 { 489 // Note that we have an entry, and entries can be deleted only during GC, 490 // so we cannot allow GC to occur while we're holding this entry. 491 492 // We're using a NoSafepointVerifier to catch any place where we 493 // might potentially do a GC at all. 494 // Dictionary::do_unloading() asserts that classes in SD are only 495 // unloaded at a safepoint. Anonymous classes are not in SD. 496 NoSafepointVerifier nosafepoint; 497 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 498 protection_domain, THREAD); 499 } 500 } 501} 502 503// We only get here if this thread finds that another thread 504// has already claimed the placeholder token for the current operation, 505// but that other thread either never owned or gave up the 506// object lock 507// Waits on SystemDictionary_lock to indicate placeholder table updated 508// On return, caller must recheck placeholder table state 509// 510// We only get here if 511// 1) custom classLoader, i.e. not bootstrap classloader 512// 2) UnsyncloadClass not set 513// 3) custom classLoader has broken the class loader objectLock 514// so another thread got here in parallel 515// 516// lockObject must be held. 517// Complicated dance due to lock ordering: 518// Must first release the classloader object lock to 519// allow initial definer to complete the class definition 520// and to avoid deadlock 521// Reclaim classloader lock object with same original recursion count 522// Must release SystemDictionary_lock after notify, since 523// class loader lock must be claimed before SystemDictionary_lock 524// to prevent deadlocks 525// 526// The notify allows applications that did an untimed wait() on 527// the classloader object lock to not hang. 528void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 529 assert_lock_strong(SystemDictionary_lock); 530 531 bool calledholdinglock 532 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 533 assert(calledholdinglock,"must hold lock for notify"); 534 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 535 ObjectSynchronizer::notifyall(lockObject, THREAD); 536 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 537 SystemDictionary_lock->wait(); 538 SystemDictionary_lock->unlock(); 539 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 540 SystemDictionary_lock->lock(); 541} 542 543// If the class in is in the placeholder table, class loading is in progress 544// For cases where the application changes threads to load classes, it 545// is critical to ClassCircularity detection that we try loading 546// the superclass on the same thread internally, so we do parallel 547// super class loading here. 548// This also is critical in cases where the original thread gets stalled 549// even in non-circularity situations. 550// Note: must call resolve_super_or_fail even if null super - 551// to force placeholder entry creation for this class for circularity detection 552// Caller must check for pending exception 553// Returns non-null Klass* if other thread has completed load 554// and we are done, 555// If return null Klass* and no pending exception, the caller must load the class 556instanceKlassHandle SystemDictionary::handle_parallel_super_load( 557 Symbol* name, Symbol* superclassname, Handle class_loader, 558 Handle protection_domain, Handle lockObject, TRAPS) { 559 560 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 561 ClassLoaderData* loader_data = class_loader_data(class_loader); 562 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 563 int d_index = dictionary()->hash_to_index(d_hash); 564 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 565 int p_index = placeholders()->hash_to_index(p_hash); 566 567 // superk is not used, resolve_super called for circularity check only 568 // This code is reached in two situations. One if this thread 569 // is loading the same class twice (e.g. ClassCircularity, or 570 // java.lang.instrument). 571 // The second is if another thread started the resolve_super first 572 // and has not yet finished. 573 // In both cases the original caller will clean up the placeholder 574 // entry on error. 575 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 576 superclassname, 577 class_loader, 578 protection_domain, 579 true, 580 CHECK_(nh)); 581 582 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 583 // Serial class loaders and bootstrap classloader do wait for superclass loads 584 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 585 MutexLocker mu(SystemDictionary_lock, THREAD); 586 // Check if classloading completed while we were loading superclass or waiting 587 Klass* check = find_class(d_index, d_hash, name, loader_data); 588 if (check != NULL) { 589 // Klass is already loaded, so just return it 590 return(instanceKlassHandle(THREAD, check)); 591 } else { 592 return nh; 593 } 594 } 595 596 // must loop to both handle other placeholder updates 597 // and spurious notifications 598 bool super_load_in_progress = true; 599 PlaceholderEntry* placeholder; 600 while (super_load_in_progress) { 601 MutexLocker mu(SystemDictionary_lock, THREAD); 602 // Check if classloading completed while we were loading superclass or waiting 603 Klass* check = find_class(d_index, d_hash, name, loader_data); 604 if (check != NULL) { 605 // Klass is already loaded, so just return it 606 return(instanceKlassHandle(THREAD, check)); 607 } else { 608 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 609 if (placeholder && placeholder->super_load_in_progress() ){ 610 // Before UnsyncloadClass: 611 // We only get here if the application has released the 612 // classloader lock when another thread was in the middle of loading a 613 // superclass/superinterface for this class, and now 614 // this thread is also trying to load this class. 615 // To minimize surprises, the first thread that started to 616 // load a class should be the one to complete the loading 617 // with the classfile it initially expected. 618 // This logic has the current thread wait once it has done 619 // all the superclass/superinterface loading it can, until 620 // the original thread completes the class loading or fails 621 // If it completes we will use the resulting InstanceKlass 622 // which we will find below in the systemDictionary. 623 // We also get here for parallel bootstrap classloader 624 if (class_loader.is_null()) { 625 SystemDictionary_lock->wait(); 626 } else { 627 double_lock_wait(lockObject, THREAD); 628 } 629 } else { 630 // If not in SD and not in PH, other thread's load must have failed 631 super_load_in_progress = false; 632 } 633 } 634 } 635 return (nh); 636} 637 638// utility function for class load event 639static void post_class_load_event(const Ticks& start_time, 640 instanceKlassHandle k, 641 Handle initiating_loader) { 642#if INCLUDE_TRACE 643 EventClassLoad event(UNTIMED); 644 if (event.should_commit()) { 645 event.set_starttime(start_time); 646 event.set_loadedClass(k()); 647 oop defining_class_loader = k->class_loader(); 648 event.set_definingClassLoader(defining_class_loader != NULL ? 649 defining_class_loader->klass() : (Klass*)NULL); 650 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader(); 651 event.set_initiatingClassLoader(class_loader != NULL ? 652 class_loader->klass() : (Klass*)NULL); 653 event.commit(); 654 } 655#endif // INCLUDE_TRACE 656} 657 658// utility function for class define event 659static void class_define_event(instanceKlassHandle k) { 660#if INCLUDE_TRACE 661 EventClassDefine event(UNTIMED); 662 if (event.should_commit()) { 663 event.set_definedClass(k()); 664 oop defining_class_loader = k->class_loader(); 665 event.set_definingClassLoader(defining_class_loader != NULL ? 666 defining_class_loader->klass() : (Klass*)NULL); 667 event.commit(); 668 } 669#endif // INCLUDE_TRACE 670} 671 672 673Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 674 Handle class_loader, 675 Handle protection_domain, 676 TRAPS) { 677 assert(name != NULL && !FieldType::is_array(name) && 678 !FieldType::is_obj(name), "invalid class name"); 679 680 Ticks class_load_start_time = Ticks::now(); 681 682 // Fix for 4474172; see evaluation for more details 683 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 684 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 685 686 // Do lookup to see if class already exist and the protection domain 687 // has the right access 688 // This call uses find which checks protection domain already matches 689 // All subsequent calls use find_class, and set has_loaded_class so that 690 // before we return a result we call out to java to check for valid protection domain 691 // to allow returning the Klass* and add it to the pd_set if it is valid 692 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 693 int d_index = dictionary()->hash_to_index(d_hash); 694 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 695 protection_domain, THREAD); 696 if (probe != NULL) return probe; 697 698 699 // Non-bootstrap class loaders will call out to class loader and 700 // define via jvm/jni_DefineClass which will acquire the 701 // class loader object lock to protect against multiple threads 702 // defining the class in parallel by accident. 703 // This lock must be acquired here so the waiter will find 704 // any successful result in the SystemDictionary and not attempt 705 // the define 706 // ParallelCapable Classloaders and the bootstrap classloader, 707 // or all classloaders with UnsyncloadClass do not acquire lock here 708 bool DoObjectLock = true; 709 if (is_parallelCapable(class_loader)) { 710 DoObjectLock = false; 711 } 712 713 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 714 int p_index = placeholders()->hash_to_index(p_hash); 715 716 // Class is not in SystemDictionary so we have to do loading. 717 // Make sure we are synchronized on the class loader before we proceed 718 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 719 check_loader_lock_contention(lockObject, THREAD); 720 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 721 722 // Check again (after locking) if class already exist in SystemDictionary 723 bool class_has_been_loaded = false; 724 bool super_load_in_progress = false; 725 bool havesupername = false; 726 instanceKlassHandle k; 727 PlaceholderEntry* placeholder; 728 Symbol* superclassname = NULL; 729 730 { 731 MutexLocker mu(SystemDictionary_lock, THREAD); 732 Klass* check = find_class(d_index, d_hash, name, loader_data); 733 if (check != NULL) { 734 // Klass is already loaded, so just return it 735 class_has_been_loaded = true; 736 k = instanceKlassHandle(THREAD, check); 737 } else { 738 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 739 if (placeholder && placeholder->super_load_in_progress()) { 740 super_load_in_progress = true; 741 if (placeholder->havesupername() == true) { 742 superclassname = placeholder->supername(); 743 havesupername = true; 744 } 745 } 746 } 747 } 748 749 // If the class is in the placeholder table, class loading is in progress 750 if (super_load_in_progress && havesupername==true) { 751 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 752 class_loader, protection_domain, lockObject, THREAD); 753 if (HAS_PENDING_EXCEPTION) { 754 return NULL; 755 } 756 if (!k.is_null()) { 757 class_has_been_loaded = true; 758 } 759 } 760 761 bool throw_circularity_error = false; 762 if (!class_has_been_loaded) { 763 bool load_instance_added = false; 764 765 // add placeholder entry to record loading instance class 766 // Five cases: 767 // All cases need to prevent modifying bootclasssearchpath 768 // in parallel with a classload of same classname 769 // Redefineclasses uses existence of the placeholder for the duration 770 // of the class load to prevent concurrent redefinition of not completely 771 // defined classes. 772 // case 1. traditional classloaders that rely on the classloader object lock 773 // - no other need for LOAD_INSTANCE 774 // case 2. traditional classloaders that break the classloader object lock 775 // as a deadlock workaround. Detection of this case requires that 776 // this check is done while holding the classloader object lock, 777 // and that lock is still held when calling classloader's loadClass. 778 // For these classloaders, we ensure that the first requestor 779 // completes the load and other requestors wait for completion. 780 // case 3. UnsyncloadClass - don't use objectLocker 781 // With this flag, we allow parallel classloading of a 782 // class/classloader pair 783 // case4. Bootstrap classloader - don't own objectLocker 784 // This classloader supports parallelism at the classloader level, 785 // but only allows a single load of a class/classloader pair. 786 // No performance benefit and no deadlock issues. 787 // case 5. parallelCapable user level classloaders - without objectLocker 788 // Allow parallel classloading of a class/classloader pair 789 790 { 791 MutexLocker mu(SystemDictionary_lock, THREAD); 792 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 793 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 794 if (oldprobe) { 795 // only need check_seen_thread once, not on each loop 796 // 6341374 java/lang/Instrument with -Xcomp 797 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 798 throw_circularity_error = true; 799 } else { 800 // case 1: traditional: should never see load_in_progress. 801 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 802 803 // case 4: bootstrap classloader: prevent futile classloading, 804 // wait on first requestor 805 if (class_loader.is_null()) { 806 SystemDictionary_lock->wait(); 807 } else { 808 // case 2: traditional with broken classloader lock. wait on first 809 // requestor. 810 double_lock_wait(lockObject, THREAD); 811 } 812 // Check if classloading completed while we were waiting 813 Klass* check = find_class(d_index, d_hash, name, loader_data); 814 if (check != NULL) { 815 // Klass is already loaded, so just return it 816 k = instanceKlassHandle(THREAD, check); 817 class_has_been_loaded = true; 818 } 819 // check if other thread failed to load and cleaned up 820 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 821 } 822 } 823 } 824 } 825 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 826 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 827 // LOAD_INSTANCE in parallel 828 829 if (!throw_circularity_error && !class_has_been_loaded) { 830 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 831 load_instance_added = true; 832 // For class loaders that do not acquire the classloader object lock, 833 // if they did not catch another thread holding LOAD_INSTANCE, 834 // need a check analogous to the acquire ObjectLocker/find_class 835 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 836 // one final check if the load has already completed 837 // class loaders holding the ObjectLock shouldn't find the class here 838 Klass* check = find_class(d_index, d_hash, name, loader_data); 839 if (check != NULL) { 840 // Klass is already loaded, so return it after checking/adding protection domain 841 k = instanceKlassHandle(THREAD, check); 842 class_has_been_loaded = true; 843 } 844 } 845 } 846 847 // must throw error outside of owning lock 848 if (throw_circularity_error) { 849 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 850 ResourceMark rm(THREAD); 851 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 852 } 853 854 if (!class_has_been_loaded) { 855 856 // Do actual loading 857 k = load_instance_class(name, class_loader, THREAD); 858 859 // For UnsyncloadClass only 860 // If they got a linkageError, check if a parallel class load succeeded. 861 // If it did, then for bytecode resolution the specification requires 862 // that we return the same result we did for the other thread, i.e. the 863 // successfully loaded InstanceKlass 864 // Should not get here for classloaders that support parallelism 865 // with the new cleaner mechanism, even with AllowParallelDefineClass 866 // Bootstrap goes through here to allow for an extra guarantee check 867 if (UnsyncloadClass || (class_loader.is_null())) { 868 if (k.is_null() && HAS_PENDING_EXCEPTION 869 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 870 MutexLocker mu(SystemDictionary_lock, THREAD); 871 Klass* check = find_class(d_index, d_hash, name, loader_data); 872 if (check != NULL) { 873 // Klass is already loaded, so just use it 874 k = instanceKlassHandle(THREAD, check); 875 CLEAR_PENDING_EXCEPTION; 876 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 877 } 878 } 879 } 880 881 // If everything was OK (no exceptions, no null return value), and 882 // class_loader is NOT the defining loader, do a little more bookkeeping. 883 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 884 k->class_loader() != class_loader()) { 885 886 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 887 888 // Need to check for a PENDING_EXCEPTION again; check_constraints 889 // can throw and doesn't use the CHECK macro. 890 if (!HAS_PENDING_EXCEPTION) { 891 { // Grabbing the Compile_lock prevents systemDictionary updates 892 // during compilations. 893 MutexLocker mu(Compile_lock, THREAD); 894 update_dictionary(d_index, d_hash, p_index, p_hash, 895 k, class_loader, THREAD); 896 } 897 898 if (JvmtiExport::should_post_class_load()) { 899 Thread *thread = THREAD; 900 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 901 JvmtiExport::post_class_load((JavaThread *) thread, k()); 902 } 903 } 904 } 905 } // load_instance_class loop 906 907 if (load_instance_added == true) { 908 // clean up placeholder entries for LOAD_INSTANCE success or error 909 // This brackets the SystemDictionary updates for both defining 910 // and initiating loaders 911 MutexLocker mu(SystemDictionary_lock, THREAD); 912 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 913 SystemDictionary_lock->notify_all(); 914 } 915 } 916 917 if (HAS_PENDING_EXCEPTION || k.is_null()) { 918 return NULL; 919 } 920 921 post_class_load_event(class_load_start_time, k, class_loader); 922 923#ifdef ASSERT 924 { 925 ClassLoaderData* loader_data = k->class_loader_data(); 926 MutexLocker mu(SystemDictionary_lock, THREAD); 927 Klass* kk = find_class(name, loader_data); 928 assert(kk == k(), "should be present in dictionary"); 929 } 930#endif 931 932 // return if the protection domain in NULL 933 if (protection_domain() == NULL) return k(); 934 935 // Check the protection domain has the right access 936 { 937 MutexLocker mu(SystemDictionary_lock, THREAD); 938 // Note that we have an entry, and entries can be deleted only during GC, 939 // so we cannot allow GC to occur while we're holding this entry. 940 // We're using a NoSafepointVerifier to catch any place where we 941 // might potentially do a GC at all. 942 // Dictionary::do_unloading() asserts that classes in SD are only 943 // unloaded at a safepoint. Anonymous classes are not in SD. 944 NoSafepointVerifier nosafepoint; 945 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 946 loader_data, 947 protection_domain)) { 948 return k(); 949 } 950 } 951 952 // Verify protection domain. If it fails an exception is thrown 953 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 954 955 return k(); 956} 957 958 959// This routine does not lock the system dictionary. 960// 961// Since readers don't hold a lock, we must make sure that system 962// dictionary entries are only removed at a safepoint (when only one 963// thread is running), and are added to in a safe way (all links must 964// be updated in an MT-safe manner). 965// 966// Callers should be aware that an entry could be added just after 967// _dictionary->bucket(index) is read here, so the caller will not see 968// the new entry. 969 970Klass* SystemDictionary::find(Symbol* class_name, 971 Handle class_loader, 972 Handle protection_domain, 973 TRAPS) { 974 975 // The result of this call should be consistent with the result 976 // of the call to resolve_instance_class_or_null(). 977 // See evaluation 6790209 and 4474172 for more details. 978 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 979 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 980 981 if (loader_data == NULL) { 982 // If the ClassLoaderData has not been setup, 983 // then the class loader has no entries in the dictionary. 984 return NULL; 985 } 986 987 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 988 int d_index = dictionary()->hash_to_index(d_hash); 989 990 { 991 // Note that we have an entry, and entries can be deleted only during GC, 992 // so we cannot allow GC to occur while we're holding this entry. 993 // We're using a NoSafepointVerifier to catch any place where we 994 // might potentially do a GC at all. 995 // Dictionary::do_unloading() asserts that classes in SD are only 996 // unloaded at a safepoint. Anonymous classes are not in SD. 997 NoSafepointVerifier nosafepoint; 998 return dictionary()->find(d_index, d_hash, class_name, loader_data, 999 protection_domain, THREAD); 1000 } 1001} 1002 1003 1004// Look for a loaded instance or array klass by name. Do not do any loading. 1005// return NULL in case of error. 1006Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 1007 Handle class_loader, 1008 Handle protection_domain, 1009 TRAPS) { 1010 Klass* k = NULL; 1011 assert(class_name != NULL, "class name must be non NULL"); 1012 1013 if (FieldType::is_array(class_name)) { 1014 // The name refers to an array. Parse the name. 1015 // dimension and object_key in FieldArrayInfo are assigned as a 1016 // side-effect of this call 1017 FieldArrayInfo fd; 1018 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 1019 if (t != T_OBJECT) { 1020 k = Universe::typeArrayKlassObj(t); 1021 } else { 1022 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 1023 } 1024 if (k != NULL) { 1025 k = k->array_klass_or_null(fd.dimension()); 1026 } 1027 } else { 1028 k = find(class_name, class_loader, protection_domain, THREAD); 1029 } 1030 return k; 1031} 1032 1033// Note: this method is much like resolve_from_stream, but 1034// updates no supplemental data structures. 1035// TODO consolidate the two methods with a helper routine? 1036Klass* SystemDictionary::parse_stream(Symbol* class_name, 1037 Handle class_loader, 1038 Handle protection_domain, 1039 ClassFileStream* st, 1040 const Klass* host_klass, 1041 GrowableArray<Handle>* cp_patches, 1042 TRAPS) { 1043 1044 Ticks class_load_start_time = Ticks::now(); 1045 1046 ClassLoaderData* loader_data; 1047 if (host_klass != NULL) { 1048 // Create a new CLD for anonymous class, that uses the same class loader 1049 // as the host_klass 1050 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 1051 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping"); 1052 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 1053 loader_data->record_dependency(host_klass, CHECK_NULL); 1054 } else { 1055 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1056 } 1057 1058 assert(st != NULL, "invariant"); 1059 assert(st->need_verify(), "invariant"); 1060 1061 // Parse stream and create a klass. 1062 // Note that we do this even though this klass might 1063 // already be present in the SystemDictionary, otherwise we would not 1064 // throw potential ClassFormatErrors. 1065 1066 instanceKlassHandle k = KlassFactory::create_from_stream(st, 1067 class_name, 1068 loader_data, 1069 protection_domain, 1070 host_klass, 1071 cp_patches, 1072 NULL, // parsed_name 1073 THREAD); 1074 1075 if (host_klass != NULL && k.not_null()) { 1076 // If it's anonymous, initialize it now, since nobody else will. 1077 1078 { 1079 MutexLocker mu_r(Compile_lock, THREAD); 1080 1081 // Add to class hierarchy, initialize vtables, and do possible 1082 // deoptimizations. 1083 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1084 1085 // But, do not add to system dictionary. 1086 1087 // compiled code dependencies need to be validated anyway 1088 notice_modification(); 1089 } 1090 1091 // Rewrite and patch constant pool here. 1092 k->link_class(CHECK_NULL); 1093 if (cp_patches != NULL) { 1094 k->constants()->patch_resolved_references(cp_patches); 1095 } 1096 k->eager_initialize(CHECK_NULL); 1097 1098 // notify jvmti 1099 if (JvmtiExport::should_post_class_load()) { 1100 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1101 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1102 } 1103 1104 post_class_load_event(class_load_start_time, k, class_loader); 1105 } 1106 assert(host_klass != NULL || NULL == cp_patches, 1107 "cp_patches only found with host_klass"); 1108 1109 return k(); 1110} 1111 1112// Add a klass to the system from a stream (called by jni_DefineClass and 1113// JVM_DefineClass). 1114// Note: class_name can be NULL. In that case we do not know the name of 1115// the class until we have parsed the stream. 1116 1117Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1118 Handle class_loader, 1119 Handle protection_domain, 1120 ClassFileStream* st, 1121 TRAPS) { 1122 1123 // Classloaders that support parallelism, e.g. bootstrap classloader, 1124 // or all classloaders with UnsyncloadClass do not acquire lock here 1125 bool DoObjectLock = true; 1126 if (is_parallelCapable(class_loader)) { 1127 DoObjectLock = false; 1128 } 1129 1130 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1131 1132 // Make sure we are synchronized on the class loader before we proceed 1133 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1134 check_loader_lock_contention(lockObject, THREAD); 1135 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1136 1137 assert(st != NULL, "invariant"); 1138 1139 // Parse the stream and create a klass. 1140 // Note that we do this even though this klass might 1141 // already be present in the SystemDictionary, otherwise we would not 1142 // throw potential ClassFormatErrors. 1143 // 1144 // Note: "parsed_name" is updated. 1145 TempNewSymbol parsed_name = NULL; 1146 1147 instanceKlassHandle k; 1148 1149#if INCLUDE_CDS 1150 k = SystemDictionaryShared::lookup_from_stream(class_name, 1151 class_loader, 1152 protection_domain, 1153 st, 1154 CHECK_NULL); 1155#endif 1156 1157 if (k.not_null()) { 1158 parsed_name = k->name(); 1159 } else { 1160 if (st->buffer() == NULL) { 1161 return NULL; 1162 } 1163 k = KlassFactory::create_from_stream(st, 1164 class_name, 1165 loader_data, 1166 protection_domain, 1167 NULL, // host_klass 1168 NULL, // cp_patches 1169 &parsed_name, 1170 THREAD); 1171 } 1172 1173 const char* pkg = "java/"; 1174 if (!HAS_PENDING_EXCEPTION && 1175 !class_loader.is_null() && 1176 !SystemDictionary::is_platform_class_loader(class_loader) && 1177 parsed_name != NULL && 1178 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1179 // It is illegal to define classes in the "java." package from 1180 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1181 ResourceMark rm(THREAD); 1182 TempNewSymbol pkg_name = InstanceKlass::package_from_name(parsed_name, CHECK_NULL); 1183 assert(pkg_name != NULL, "Error in parsing package name starting with 'java/'"); 1184 char* name = pkg_name->as_C_string(); 1185 StringUtils::replace_no_expand(name, "/", "."); 1186 const char* msg_text = "Prohibited package name: "; 1187 size_t len = strlen(msg_text) + strlen(name) + 1; 1188 char* message = NEW_RESOURCE_ARRAY(char, len); 1189 jio_snprintf(message, len, "%s%s", msg_text, name); 1190 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1191 vmSymbols::java_lang_SecurityException(), message); 1192 } 1193 1194 if (!HAS_PENDING_EXCEPTION) { 1195 assert(parsed_name != NULL, "Sanity"); 1196 assert(class_name == NULL || class_name == parsed_name, "name mismatch"); 1197 // Verification prevents us from creating names with dots in them, this 1198 // asserts that that's the case. 1199 assert(is_internal_format(parsed_name), 1200 "external class name format used internally"); 1201 1202 // Add class just loaded 1203 // If a class loader supports parallel classloading handle parallel define requests 1204 // find_or_define_instance_class may return a different InstanceKlass 1205 if (is_parallelCapable(class_loader)) { 1206 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); 1207 } else { 1208 define_instance_class(k, THREAD); 1209 } 1210 } 1211 1212 // Make sure we have an entry in the SystemDictionary on success 1213 debug_only( { 1214 if (!HAS_PENDING_EXCEPTION) { 1215 assert(parsed_name != NULL, "parsed_name is still null?"); 1216 Symbol* h_name = k->name(); 1217 ClassLoaderData *defining_loader_data = k->class_loader_data(); 1218 1219 MutexLocker mu(SystemDictionary_lock, THREAD); 1220 1221 Klass* check = find_class(parsed_name, loader_data); 1222 assert(check == k(), "should be present in the dictionary"); 1223 1224 Klass* check2 = find_class(h_name, defining_loader_data); 1225 assert(check == check2, "name inconsistancy in SystemDictionary"); 1226 } 1227 } ); 1228 1229 return k(); 1230} 1231 1232#if INCLUDE_CDS 1233void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1234 int number_of_entries) { 1235 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1236 "bad shared dictionary size."); 1237 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1238} 1239 1240 1241// If there is a shared dictionary, then find the entry for the 1242// given shared system class, if any. 1243 1244Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1245 if (shared_dictionary() != NULL) { 1246 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1247 int d_index = shared_dictionary()->hash_to_index(d_hash); 1248 1249 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1250 } else { 1251 return NULL; 1252 } 1253} 1254 1255 1256// Load a class from the shared spaces (found through the shared system 1257// dictionary). Force the superclass and all interfaces to be loaded. 1258// Update the class definition to include sibling classes and no 1259// subclasses (yet). [Classes in the shared space are not part of the 1260// object hierarchy until loaded.] 1261 1262instanceKlassHandle SystemDictionary::load_shared_class( 1263 Symbol* class_name, Handle class_loader, TRAPS) { 1264 // Don't load shared class when JvmtiExport::should_post_class_file_load_hook() 1265 // is enabled since posting CFLH is not supported when loading shared class. 1266 if (!JvmtiExport::should_post_class_file_load_hook()) { 1267 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1268 // Make sure we only return the boot class for the NULL classloader. 1269 if (ik.not_null() && 1270 ik->is_shared_boot_class() && class_loader.is_null()) { 1271 Handle protection_domain; 1272 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1273 } 1274 } 1275 return instanceKlassHandle(); 1276} 1277 1278// Check if a shared class can be loaded by the specific classloader: 1279// 1280// NULL classloader: 1281// - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. 1282// - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must 1283// be defined in an unnamed module. 1284bool SystemDictionary::is_shared_class_visible(Symbol* class_name, 1285 instanceKlassHandle ik, 1286 Handle class_loader, TRAPS) { 1287 ResourceMark rm; 1288 int path_index = ik->shared_classpath_index(); 1289 SharedClassPathEntry* ent = 1290 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index); 1291 if (!Universe::is_module_initialized()) { 1292 assert(ent->is_jrt(), 1293 "Loading non-bootstrap classes before the module system is initialized"); 1294 assert(class_loader.is_null(), "sanity"); 1295 return true; 1296 } 1297 // Get the pkg_entry from the classloader 1298 TempNewSymbol pkg_name = NULL; 1299 PackageEntry* pkg_entry = NULL; 1300 ModuleEntry* mod_entry = NULL; 1301 const char* pkg_string = NULL; 1302 ClassLoaderData* loader_data = class_loader_data(class_loader); 1303 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); 1304 if (pkg_name != NULL) { 1305 pkg_string = pkg_name->as_C_string(); 1306 if (loader_data != NULL) { 1307 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1308 } 1309 if (pkg_entry != NULL) { 1310 mod_entry = pkg_entry->module(); 1311 } 1312 } 1313 1314 if (class_loader.is_null()) { 1315 // The NULL classloader can load archived class originated from the 1316 // "modules" jimage and the -Xbootclasspath/a. For class from the 1317 // "modules" jimage, the PackageEntry/ModuleEntry must be defined 1318 // by the NULL classloader. 1319 if (mod_entry != NULL) { 1320 // PackageEntry/ModuleEntry is found in the classloader. Check if the 1321 // ModuleEntry's location agrees with the archived class' origination. 1322 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) { 1323 return true; // Module class from the "module" jimage 1324 } 1325 } 1326 1327 // If the archived class is not from the "module" jimage, the class can be 1328 // loaded by the NULL classloader if 1329 // 1330 // 1. the class is from the unamed package 1331 // 2. or, the class is not from a module defined in the NULL classloader 1332 // 3. or, the class is from an unamed module 1333 if (!ent->is_jrt() && ik->is_shared_boot_class()) { 1334 // the class is from the -Xbootclasspath/a 1335 if (pkg_string == NULL || 1336 pkg_entry == NULL || 1337 pkg_entry->in_unnamed_module()) { 1338 assert(mod_entry == NULL || 1339 mod_entry == loader_data->modules()->unnamed_module(), 1340 "the unnamed module is not defined in the classloader"); 1341 return true; 1342 } 1343 } 1344 return false; 1345 } else { 1346 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( 1347 ik, class_loader, pkg_string, pkg_name, 1348 pkg_entry, mod_entry, CHECK_(false)); 1349 return res; 1350 } 1351} 1352 1353instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik, 1354 Handle class_loader, 1355 Handle protection_domain, TRAPS) { 1356 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1357 if (JvmtiExport::should_post_class_file_load_hook()) { 1358 // Don't load shared class when JvmtiExport::should_post_class_file_load_hook() 1359 // is enabled since posting CFLH is not supported when loading shared class. 1360 return nh; 1361 } 1362 1363 if (ik.not_null()) { 1364 Symbol* class_name = ik->name(); 1365 1366 bool visible = is_shared_class_visible( 1367 class_name, ik, class_loader, CHECK_(nh)); 1368 if (!visible) { 1369 return nh; 1370 } 1371 1372 // Resolve the superclass and interfaces. They must be the same 1373 // as in dump time, because the layout of <ik> depends on 1374 // the specific layout of ik->super() and ik->local_interfaces(). 1375 // 1376 // If unexpected superclass or interfaces are found, we cannot 1377 // load <ik> from the shared archive. 1378 1379 if (ik->super() != NULL) { 1380 Symbol* cn = ik->super()->name(); 1381 Klass *s = resolve_super_or_fail(class_name, cn, 1382 class_loader, protection_domain, true, CHECK_(nh)); 1383 if (s != ik->super()) { 1384 // The dynamically resolved super class is not the same as the one we used during dump time, 1385 // so we cannot use ik. 1386 return nh; 1387 } else { 1388 assert(s->is_shared(), "must be"); 1389 } 1390 } 1391 1392 Array<Klass*>* interfaces = ik->local_interfaces(); 1393 int num_interfaces = interfaces->length(); 1394 for (int index = 0; index < num_interfaces; index++) { 1395 Klass* k = interfaces->at(index); 1396 1397 // Note: can not use InstanceKlass::cast here because 1398 // interfaces' InstanceKlass's C++ vtbls haven't been 1399 // reinitialized yet (they will be once the interface classes 1400 // are loaded) 1401 Symbol* name = k->name(); 1402 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh)); 1403 if (k != i) { 1404 // The dynamically resolved interface class is not the same as the one we used during dump time, 1405 // so we cannot use ik. 1406 return nh; 1407 } else { 1408 assert(i->is_shared(), "must be"); 1409 } 1410 } 1411 1412 // Adjust methods to recover missing data. They need addresses for 1413 // interpreter entry points and their default native method address 1414 // must be reset. 1415 1416 // Updating methods must be done under a lock so multiple 1417 // threads don't update these in parallel 1418 // 1419 // Shared classes are all currently loaded by either the bootstrap or 1420 // internal parallel class loaders, so this will never cause a deadlock 1421 // on a custom class loader lock. 1422 1423 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1424 { 1425 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1426 check_loader_lock_contention(lockObject, THREAD); 1427 ObjectLocker ol(lockObject, THREAD, true); 1428 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh)); 1429 } 1430 1431 if (log_is_enabled(Info, class, load)) { 1432 ik()->print_loading_log(LogLevel::Info, loader_data, NULL, NULL); 1433 } 1434 // No 'else' here as logging levels are not mutually exclusive 1435 1436 if (log_is_enabled(Debug, class, load)) { 1437 ik()->print_loading_log(LogLevel::Debug, loader_data, NULL, NULL); 1438 } 1439 1440 // For boot loader, ensure that GetSystemPackage knows that a class in this 1441 // package was loaded. 1442 if (class_loader.is_null()) { 1443 int path_index = ik->shared_classpath_index(); 1444 ResourceMark rm; 1445 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); 1446 } 1447 1448 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1449 // Only dump the classes that can be stored into CDS archive 1450 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1451 ResourceMark rm(THREAD); 1452 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1453 classlist_file->flush(); 1454 } 1455 } 1456 1457 // notify a class loaded from shared object 1458 ClassLoadingService::notify_class_loaded(ik(), true /* shared class */); 1459 } 1460 return ik; 1461} 1462#endif // INCLUDE_CDS 1463 1464instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1465 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1466 1467 if (class_loader.is_null()) { 1468 ResourceMark rm; 1469 PackageEntry* pkg_entry = NULL; 1470 bool search_only_bootloader_append = false; 1471 ClassLoaderData *loader_data = class_loader_data(class_loader); 1472 1473 // Find the package in the boot loader's package entry table. 1474 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); 1475 if (pkg_name != NULL) { 1476 pkg_entry = loader_data->packages()->lookup_only(pkg_name); 1477 } 1478 1479 // Prior to attempting to load the class, enforce the boot loader's 1480 // visibility boundaries. 1481 if (!Universe::is_module_initialized()) { 1482 // During bootstrapping, prior to module initialization, any 1483 // class attempting to be loaded must be checked against the 1484 // java.base packages in the boot loader's PackageEntryTable. 1485 // No class outside of java.base is allowed to be loaded during 1486 // this bootstrapping window. 1487 if (!DumpSharedSpaces) { 1488 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1489 // Class is either in the unnamed package or in 1490 // a named package within the unnamed module. Either 1491 // case is outside of java.base, do not attempt to 1492 // load the class post java.base definition. If 1493 // java.base has not been defined, let the class load 1494 // and its package will be checked later by 1495 // ModuleEntryTable::verify_javabase_packages. 1496 if (ModuleEntryTable::javabase_defined()) { 1497 return nh; 1498 } 1499 } else { 1500 // Check that the class' package is defined within java.base. 1501 ModuleEntry* mod_entry = pkg_entry->module(); 1502 Symbol* mod_entry_name = mod_entry->name(); 1503 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { 1504 return nh; 1505 } 1506 } 1507 } 1508 } else { 1509 assert(!DumpSharedSpaces, "Archive dumped after module system initialization"); 1510 // After the module system has been initialized, check if the class' 1511 // package is in a module defined to the boot loader. 1512 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { 1513 // Class is either in the unnamed package, in a named package 1514 // within a module not defined to the boot loader or in a 1515 // a named package within the unnamed module. In all cases, 1516 // limit visibility to search for the class only in the boot 1517 // loader's append path. 1518 search_only_bootloader_append = true; 1519 } 1520 } 1521 1522 // Prior to bootstrapping's module initialization, never load a class outside 1523 // of the boot loader's module path 1524 assert(Universe::is_module_initialized() || DumpSharedSpaces || 1525 !search_only_bootloader_append, 1526 "Attempt to load a class outside of boot loader's module path"); 1527 1528 // Search the shared system dictionary for classes preloaded into the 1529 // shared spaces. 1530 instanceKlassHandle k; 1531 { 1532#if INCLUDE_CDS 1533 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1534 k = load_shared_class(class_name, class_loader, THREAD); 1535#endif 1536 } 1537 1538 if (k.is_null()) { 1539 // Use VM class loader 1540 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1541 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_(nh)); 1542 } 1543 1544 // find_or_define_instance_class may return a different InstanceKlass 1545 if (!k.is_null()) { 1546 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1547 } 1548 return k; 1549 } else { 1550 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1551 ResourceMark rm(THREAD); 1552 1553 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1554 JavaThread* jt = (JavaThread*) THREAD; 1555 1556 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1557 ClassLoader::perf_app_classload_selftime(), 1558 ClassLoader::perf_app_classload_count(), 1559 jt->get_thread_stat()->perf_recursion_counts_addr(), 1560 jt->get_thread_stat()->perf_timers_addr(), 1561 PerfClassTraceTime::CLASS_LOAD); 1562 1563 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1564 // Translate to external class name format, i.e., convert '/' chars to '.' 1565 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1566 1567 JavaValue result(T_OBJECT); 1568 1569 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1570 1571 // Call public unsynchronized loadClass(String) directly for all class loaders 1572 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1573 // acquire a class-name based lock rather than the class loader object lock. 1574 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1575 // so the call to loadClassInternal() was not required. 1576 // 1577 // UnsyncloadClass flag means both call loadClass(String) and do 1578 // not acquire the class loader lock even for class loaders that are 1579 // not parallelCapable. This was a risky transitional 1580 // flag for diagnostic purposes only. It is risky to call 1581 // custom class loaders without synchronization. 1582 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1583 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1584 // Do NOT assume this will be supported in future releases. 1585 // 1586 // Added MustCallLoadClassInternal in case we discover in the field 1587 // a customer that counts on this call 1588 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1589 JavaCalls::call_special(&result, 1590 class_loader, 1591 spec_klass, 1592 vmSymbols::loadClassInternal_name(), 1593 vmSymbols::string_class_signature(), 1594 string, 1595 CHECK_(nh)); 1596 } else { 1597 JavaCalls::call_virtual(&result, 1598 class_loader, 1599 spec_klass, 1600 vmSymbols::loadClass_name(), 1601 vmSymbols::string_class_signature(), 1602 string, 1603 CHECK_(nh)); 1604 } 1605 1606 assert(result.get_type() == T_OBJECT, "just checking"); 1607 oop obj = (oop) result.get_jobject(); 1608 1609 // Primitive classes return null since forName() can not be 1610 // used to obtain any of the Class objects representing primitives or void 1611 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1612 instanceKlassHandle k = 1613 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1614 // For user defined Java class loaders, check that the name returned is 1615 // the same as that requested. This check is done for the bootstrap 1616 // loader when parsing the class file. 1617 if (class_name == k->name()) { 1618 return k; 1619 } 1620 } 1621 // Class is not found or has the wrong name, return NULL 1622 return nh; 1623 } 1624} 1625 1626void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1627 1628 ClassLoaderData* loader_data = k->class_loader_data(); 1629 Handle class_loader_h(THREAD, loader_data->class_loader()); 1630 1631 // for bootstrap and other parallel classloaders don't acquire lock, 1632 // use placeholder token 1633 // If a parallelCapable class loader calls define_instance_class instead of 1634 // find_or_define_instance_class to get here, we have a timing 1635 // hole with systemDictionary updates and check_constraints 1636 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1637 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1638 compute_loader_lock_object(class_loader_h, THREAD)), 1639 "define called without lock"); 1640 } 1641 1642 // Check class-loading constraints. Throw exception if violation is detected. 1643 // Grabs and releases SystemDictionary_lock 1644 // The check_constraints/find_class call and update_dictionary sequence 1645 // must be "atomic" for a specific class/classloader pair so we never 1646 // define two different instanceKlasses for that class/classloader pair. 1647 // Existing classloaders will call define_instance_class with the 1648 // classloader lock held 1649 // Parallel classloaders will call find_or_define_instance_class 1650 // which will require a token to perform the define class 1651 Symbol* name_h = k->name(); 1652 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1653 int d_index = dictionary()->hash_to_index(d_hash); 1654 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1655 1656 // Register class just loaded with class loader (placed in Vector) 1657 // Note we do this before updating the dictionary, as this can 1658 // fail with an OutOfMemoryError (if it does, we will *not* put this 1659 // class in the dictionary and will not update the class hierarchy). 1660 // JVMTI FollowReferences needs to find the classes this way. 1661 if (k->class_loader() != NULL) { 1662 methodHandle m(THREAD, Universe::loader_addClass_method()); 1663 JavaValue result(T_VOID); 1664 JavaCallArguments args(class_loader_h); 1665 args.push_oop(Handle(THREAD, k->java_mirror())); 1666 JavaCalls::call(&result, m, &args, CHECK); 1667 } 1668 1669 // Add the new class. We need recompile lock during update of CHA. 1670 { 1671 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1672 int p_index = placeholders()->hash_to_index(p_hash); 1673 1674 MutexLocker mu_r(Compile_lock, THREAD); 1675 1676 // Add to class hierarchy, initialize vtables, and do possible 1677 // deoptimizations. 1678 add_to_hierarchy(k, CHECK); // No exception, but can block 1679 1680 // Add to systemDictionary - so other classes can see it. 1681 // Grabs and releases SystemDictionary_lock 1682 update_dictionary(d_index, d_hash, p_index, p_hash, 1683 k, class_loader_h, THREAD); 1684 } 1685 k->eager_initialize(THREAD); 1686 1687 // notify jvmti 1688 if (JvmtiExport::should_post_class_load()) { 1689 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1690 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1691 1692 } 1693 TRACE_KLASS_DEFINITION(k, THREAD); 1694 class_define_event(k); 1695} 1696 1697// Support parallel classloading 1698// All parallel class loaders, including bootstrap classloader 1699// lock a placeholder entry for this class/class_loader pair 1700// to allow parallel defines of different classes for this class loader 1701// With AllowParallelDefine flag==true, in case they do not synchronize around 1702// FindLoadedClass/DefineClass, calls, we check for parallel 1703// loading for them, wait if a defineClass is in progress 1704// and return the initial requestor's results 1705// This flag does not apply to the bootstrap classloader. 1706// With AllowParallelDefine flag==false, call through to define_instance_class 1707// which will throw LinkageError: duplicate class definition. 1708// False is the requested default. 1709// For better performance, the class loaders should synchronize 1710// findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1711// potentially waste time reading and parsing the bytestream. 1712// Note: VM callers should ensure consistency of k/class_name,class_loader 1713instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1714 1715 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1716 Symbol* name_h = k->name(); // passed in class_name may be null 1717 ClassLoaderData* loader_data = class_loader_data(class_loader); 1718 1719 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1720 int d_index = dictionary()->hash_to_index(d_hash); 1721 1722// Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1723 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1724 int p_index = placeholders()->hash_to_index(p_hash); 1725 PlaceholderEntry* probe; 1726 1727 { 1728 MutexLocker mu(SystemDictionary_lock, THREAD); 1729 // First check if class already defined 1730 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1731 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1732 if (check != NULL) { 1733 return(instanceKlassHandle(THREAD, check)); 1734 } 1735 } 1736 1737 // Acquire define token for this class/classloader 1738 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1739 // Wait if another thread defining in parallel 1740 // All threads wait - even those that will throw duplicate class: otherwise 1741 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1742 // if other thread has not finished updating dictionary 1743 while (probe->definer() != NULL) { 1744 SystemDictionary_lock->wait(); 1745 } 1746 // Only special cases allow parallel defines and can use other thread's results 1747 // Other cases fall through, and may run into duplicate defines 1748 // caught by finding an entry in the SystemDictionary 1749 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1750 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1751 SystemDictionary_lock->notify_all(); 1752#ifdef ASSERT 1753 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1754 assert(check != NULL, "definer missed recording success"); 1755#endif 1756 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1757 } else { 1758 // This thread will define the class (even if earlier thread tried and had an error) 1759 probe->set_definer(THREAD); 1760 } 1761 } 1762 1763 define_instance_class(k, THREAD); 1764 1765 Handle linkage_exception = Handle(); // null handle 1766 1767 // definer must notify any waiting threads 1768 { 1769 MutexLocker mu(SystemDictionary_lock, THREAD); 1770 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1771 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1772 if (probe != NULL) { 1773 if (HAS_PENDING_EXCEPTION) { 1774 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1775 CLEAR_PENDING_EXCEPTION; 1776 } else { 1777 probe->set_instance_klass(k()); 1778 } 1779 probe->set_definer(NULL); 1780 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1781 SystemDictionary_lock->notify_all(); 1782 } 1783 } 1784 1785 // Can't throw exception while holding lock due to rank ordering 1786 if (linkage_exception() != NULL) { 1787 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1788 } 1789 1790 return k; 1791} 1792Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1793 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1794 if (class_loader.is_null()) { 1795 return Handle(THREAD, _system_loader_lock_obj); 1796 } else { 1797 return class_loader; 1798 } 1799} 1800 1801// This method is added to check how often we have to wait to grab loader 1802// lock. The results are being recorded in the performance counters defined in 1803// ClassLoader::_sync_systemLoaderLockContentionRate and 1804// ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1805void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1806 if (!UsePerfData) { 1807 return; 1808 } 1809 1810 assert(!loader_lock.is_null(), "NULL lock object"); 1811 1812 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1813 == ObjectSynchronizer::owner_other) { 1814 // contention will likely happen, so increment the corresponding 1815 // contention counter. 1816 if (loader_lock() == _system_loader_lock_obj) { 1817 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1818 } else { 1819 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1820 } 1821 } 1822} 1823 1824// ---------------------------------------------------------------------------- 1825// Lookup 1826 1827Klass* SystemDictionary::find_class(int index, unsigned int hash, 1828 Symbol* class_name, 1829 ClassLoaderData* loader_data) { 1830 assert_locked_or_safepoint(SystemDictionary_lock); 1831 assert (index == dictionary()->index_for(class_name, loader_data), 1832 "incorrect index?"); 1833 1834 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1835 return k; 1836} 1837 1838 1839// Basic find on classes in the midst of being loaded 1840Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1841 ClassLoaderData* loader_data) { 1842 assert_locked_or_safepoint(SystemDictionary_lock); 1843 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1844 int p_index = placeholders()->hash_to_index(p_hash); 1845 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1846} 1847 1848 1849// Used for assertions and verification only 1850Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1851 #ifndef ASSERT 1852 guarantee(VerifyBeforeGC || 1853 VerifyDuringGC || 1854 VerifyBeforeExit || 1855 VerifyDuringStartup || 1856 VerifyAfterGC, "too expensive"); 1857 #endif 1858 assert_locked_or_safepoint(SystemDictionary_lock); 1859 1860 // First look in the loaded class array 1861 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1862 int d_index = dictionary()->hash_to_index(d_hash); 1863 return find_class(d_index, d_hash, class_name, loader_data); 1864} 1865 1866 1867// Get the next class in the dictionary. 1868Klass* SystemDictionary::try_get_next_class() { 1869 return dictionary()->try_get_next_class(); 1870} 1871 1872 1873// ---------------------------------------------------------------------------- 1874// Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1875// is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1876// before a new class is used. 1877 1878void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1879 assert(k.not_null(), "just checking"); 1880 assert_locked_or_safepoint(Compile_lock); 1881 1882 // Link into hierachy. Make sure the vtables are initialized before linking into 1883 k->append_to_sibling_list(); // add to superklass/sibling list 1884 k->process_interfaces(THREAD); // handle all "implements" declarations 1885 k->set_init_state(InstanceKlass::loaded); 1886 // Now flush all code that depended on old class hierarchy. 1887 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1888 // Also, first reinitialize vtable because it may have gotten out of synch 1889 // while the new class wasn't connected to the class hierarchy. 1890 CodeCache::flush_dependents_on(k); 1891} 1892 1893// ---------------------------------------------------------------------------- 1894// GC support 1895 1896// Following roots during mark-sweep is separated in two phases. 1897// 1898// The first phase follows preloaded classes and all other system 1899// classes, since these will never get unloaded anyway. 1900// 1901// The second phase removes (unloads) unreachable classes from the 1902// system dictionary and follows the remaining classes' contents. 1903 1904void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1905 roots_oops_do(blk, NULL); 1906} 1907 1908void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1909 // Follow all system classes and temporary placeholders in dictionary 1910 dictionary()->always_strong_classes_do(closure); 1911 1912 // Placeholders. These represent classes we're actively loading. 1913 placeholders()->classes_do(closure); 1914} 1915 1916// Calculate a "good" systemdictionary size based 1917// on predicted or current loaded classes count 1918int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1919 int newsize = _old_default_sdsize; 1920 if ((classcount > 0) && !DumpSharedSpaces) { 1921 int desiredsize = classcount/_average_depth_goal; 1922 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1923 newsize = _primelist[++_sdgeneration]) { 1924 if (desiredsize <= newsize) { 1925 break; 1926 } 1927 } 1928 } 1929 return newsize; 1930} 1931 1932#ifdef ASSERT 1933class VerifySDReachableAndLiveClosure : public OopClosure { 1934private: 1935 BoolObjectClosure* _is_alive; 1936 1937 template <class T> void do_oop_work(T* p) { 1938 oop obj = oopDesc::load_decode_heap_oop(p); 1939 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); 1940 } 1941 1942public: 1943 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1944 1945 virtual void do_oop(oop* p) { do_oop_work(p); } 1946 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1947}; 1948#endif 1949 1950// Assumes classes in the SystemDictionary are only unloaded at a safepoint 1951// Note: anonymous classes are not in the SD. 1952bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, 1953 bool clean_previous_versions) { 1954 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1955 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, 1956 clean_previous_versions); 1957 if (unloading_occurred) { 1958 dictionary()->do_unloading(); 1959 constraints()->purge_loader_constraints(); 1960 resolution_errors()->purge_resolution_errors(); 1961 } 1962 // Oops referenced by the system dictionary may get unreachable independently 1963 // of the class loader (eg. cached protection domain oops). So we need to 1964 // explicitly unlink them here instead of in Dictionary::do_unloading. 1965 dictionary()->unlink(is_alive); 1966#ifdef ASSERT 1967 VerifySDReachableAndLiveClosure cl(is_alive); 1968 dictionary()->oops_do(&cl); 1969#endif 1970 return unloading_occurred; 1971} 1972 1973void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1974 strong->do_oop(&_java_system_loader); 1975 strong->do_oop(&_system_loader_lock_obj); 1976 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) 1977 1978 // Adjust dictionary 1979 dictionary()->roots_oops_do(strong, weak); 1980 1981 // Visit extra methods 1982 invoke_method_table()->oops_do(strong); 1983} 1984 1985void SystemDictionary::oops_do(OopClosure* f) { 1986 f->do_oop(&_java_system_loader); 1987 f->do_oop(&_system_loader_lock_obj); 1988 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1989 1990 // Adjust dictionary 1991 dictionary()->oops_do(f); 1992 1993 // Visit extra methods 1994 invoke_method_table()->oops_do(f); 1995} 1996 1997// Extended Class redefinition support. 1998// If one of these classes is replaced, we need to replace it in these places. 1999// KlassClosure::do_klass should take the address of a class but we can 2000// change that later. 2001void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 2002 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 2003 f->do_klass(_well_known_klasses[k]); 2004 } 2005 2006 { 2007 for (int i = 0; i < T_VOID+1; i++) { 2008 if (_box_klasses[i] != NULL) { 2009 assert(i >= T_BOOLEAN, "checking"); 2010 f->do_klass(_box_klasses[i]); 2011 } 2012 } 2013 } 2014 2015 FilteredFieldsMap::classes_do(f); 2016} 2017 2018void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 2019 f->do_klass(_abstract_ownable_synchronizer_klass); 2020} 2021 2022// Just the classes from defining class loaders 2023// Don't iterate over placeholders 2024void SystemDictionary::classes_do(void f(Klass*)) { 2025 dictionary()->classes_do(f); 2026} 2027 2028// Added for initialize_itable_for_klass 2029// Just the classes from defining class loaders 2030// Don't iterate over placeholders 2031void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 2032 dictionary()->classes_do(f, CHECK); 2033} 2034 2035// All classes, and their class loaders 2036// Don't iterate over placeholders 2037void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 2038 dictionary()->classes_do(f); 2039} 2040 2041void SystemDictionary::placeholders_do(void f(Symbol*)) { 2042 placeholders()->entries_do(f); 2043} 2044 2045void SystemDictionary::methods_do(void f(Method*)) { 2046 dictionary()->methods_do(f); 2047 invoke_method_table()->methods_do(f); 2048} 2049 2050void SystemDictionary::remove_classes_in_error_state() { 2051 dictionary()->remove_classes_in_error_state(); 2052} 2053 2054// ---------------------------------------------------------------------------- 2055// Lazily load klasses 2056 2057void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 2058 // if multiple threads calling this function, only one thread will load 2059 // the class. The other threads will find the loaded version once the 2060 // class is loaded. 2061 Klass* aos = _abstract_ownable_synchronizer_klass; 2062 if (aos == NULL) { 2063 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 2064 // Force a fence to prevent any read before the write completes 2065 OrderAccess::fence(); 2066 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); 2067 } 2068} 2069 2070// ---------------------------------------------------------------------------- 2071// Initialization 2072 2073void SystemDictionary::initialize(TRAPS) { 2074 // Allocate arrays 2075 assert(dictionary() == NULL, 2076 "SystemDictionary should only be initialized once"); 2077 _sdgeneration = 0; 2078 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 2079 _placeholders = new PlaceholderTable(_nof_buckets); 2080 _number_of_modifications = 0; 2081 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 2082 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 2083 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 2084 2085 // Allocate private object used as system class loader lock 2086 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 2087 // Initialize basic classes 2088 initialize_preloaded_classes(CHECK); 2089} 2090 2091// Compact table of directions on the initialization of klasses: 2092static const short wk_init_info[] = { 2093 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 2094 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 2095 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 2096 | (int)SystemDictionary::option ), 2097 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 2098 #undef WK_KLASS_INIT_INFO 2099 0 2100}; 2101 2102bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 2103 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2104 int info = wk_init_info[id - FIRST_WKID]; 2105 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2106 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 2107 InstanceKlass** klassp = &_well_known_klasses[id]; 2108 2109 bool must_load; 2110#if INCLUDE_JVMCI 2111 if (EnableJVMCI) { 2112 // If JVMCI is enabled we require its classes to be found. 2113 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); 2114 } else 2115#endif 2116 { 2117 must_load = (init_opt < SystemDictionary::Opt); 2118 } 2119 2120 if ((*klassp) == NULL) { 2121 Klass* k; 2122 if (must_load) { 2123 k = resolve_or_fail(symbol, true, CHECK_0); // load required class 2124 } else { 2125 k = resolve_or_null(symbol, CHECK_0); // load optional klass 2126 } 2127 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); 2128 } 2129 return ((*klassp) != NULL); 2130} 2131 2132void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 2133 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 2134 for (int id = (int)start_id; id < (int)limit_id; id++) { 2135 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 2136 int info = wk_init_info[id - FIRST_WKID]; 2137 int sid = (info >> CEIL_LG_OPTION_LIMIT); 2138 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 2139 2140 initialize_wk_klass((WKID)id, opt, CHECK); 2141 } 2142 2143 // move the starting value forward to the limit: 2144 start_id = limit_id; 2145} 2146 2147void SystemDictionary::initialize_preloaded_classes(TRAPS) { 2148 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 2149 2150 // Create the ModuleEntry for java.base. This call needs to be done here, 2151 // after vmSymbols::initialize() is called but before any classes are pre-loaded. 2152 ClassLoader::create_javabase(); 2153 2154 // Preload commonly used klasses 2155 WKID scan = FIRST_WKID; 2156 // first do Object, then String, Class 2157 if (UseSharedSpaces) { 2158 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 2159 // Initialize the constant pool for the Object_class 2160 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 2161 ik->constants()->restore_unshareable_info(CHECK); 2162 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2163 } else { 2164 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 2165 } 2166 2167 // Calculate offsets for String and Class classes since they are loaded and 2168 // can be used after this point. 2169 java_lang_String::compute_offsets(); 2170 java_lang_Class::compute_offsets(); 2171 2172 // Fixup mirrors for classes loaded before java.lang.Class. 2173 // These calls iterate over the objects currently in the perm gen 2174 // so calling them at this point is matters (not before when there 2175 // are fewer objects and not later after there are more objects 2176 // in the perm gen. 2177 Universe::initialize_basic_type_mirrors(CHECK); 2178 Universe::fixup_mirrors(CHECK); 2179 2180 // do a bunch more: 2181 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 2182 2183 // Preload ref klasses and set reference types 2184 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 2185 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 2186 2187 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 2188 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 2189 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 2190 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 2191 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 2192 2193 // JSR 292 classes 2194 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 2195 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 2196 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 2197 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 2198 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); 2199 2200 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 2201 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 2202 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 2203 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 2204 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 2205 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 2206 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 2207 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 2208 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 2209 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 2210 2211 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 2212 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 2213 _has_loadClassInternal = (method != NULL); 2214 } 2215 { // Compute whether we should use checkPackageAccess or NOT 2216 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 2217 _has_checkPackageAccess = (method != NULL); 2218 } 2219} 2220 2221// Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 2222// If so, returns the basic type it holds. If not, returns T_OBJECT. 2223BasicType SystemDictionary::box_klass_type(Klass* k) { 2224 assert(k != NULL, ""); 2225 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 2226 if (_box_klasses[i] == k) 2227 return (BasicType)i; 2228 } 2229 return T_OBJECT; 2230} 2231 2232// Constraints on class loaders. The details of the algorithm can be 2233// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 2234// Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 2235// that the system dictionary needs to maintain a set of contraints that 2236// must be satisfied by all classes in the dictionary. 2237// if defining is true, then LinkageError if already in systemDictionary 2238// if initiating loader, then ok if InstanceKlass matches existing entry 2239 2240void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 2241 instanceKlassHandle k, 2242 Handle class_loader, bool defining, 2243 TRAPS) { 2244 const char *linkage_error1 = NULL; 2245 const char *linkage_error2 = NULL; 2246 { 2247 Symbol* name = k->name(); 2248 ClassLoaderData *loader_data = class_loader_data(class_loader); 2249 2250 MutexLocker mu(SystemDictionary_lock, THREAD); 2251 2252 Klass* check = find_class(d_index, d_hash, name, loader_data); 2253 if (check != (Klass*)NULL) { 2254 // if different InstanceKlass - duplicate class definition, 2255 // else - ok, class loaded by a different thread in parallel, 2256 // we should only have found it if it was done loading and ok to use 2257 // system dictionary only holds instance classes, placeholders 2258 // also holds array classes 2259 2260 assert(check->is_instance_klass(), "noninstance in systemdictionary"); 2261 if ((defining == true) || (k() != check)) { 2262 linkage_error1 = "loader (instance of "; 2263 linkage_error2 = "): attempted duplicate class definition for name: \""; 2264 } else { 2265 return; 2266 } 2267 } 2268 2269#ifdef ASSERT 2270 Symbol* ph_check = find_placeholder(name, loader_data); 2271 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2272#endif 2273 2274 if (linkage_error1 == NULL) { 2275 if (constraints()->check_or_update(k, class_loader, name) == false) { 2276 linkage_error1 = "loader constraint violation: loader (instance of "; 2277 linkage_error2 = ") previously initiated loading for a different type with name \""; 2278 } 2279 } 2280 } 2281 2282 // Throw error now if needed (cannot throw while holding 2283 // SystemDictionary_lock because of rank ordering) 2284 2285 if (linkage_error1) { 2286 ResourceMark rm(THREAD); 2287 const char* class_loader_name = loader_name(class_loader()); 2288 char* type_name = k->name()->as_C_string(); 2289 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) + 2290 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte. 2291 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2292 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name); 2293 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2294 } 2295} 2296 2297 2298// Update system dictionary - done after check_constraint and add_to_hierachy 2299// have been called. 2300void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 2301 int p_index, unsigned int p_hash, 2302 instanceKlassHandle k, 2303 Handle class_loader, 2304 TRAPS) { 2305 // Compile_lock prevents systemDictionary updates during compilations 2306 assert_locked_or_safepoint(Compile_lock); 2307 Symbol* name = k->name(); 2308 ClassLoaderData *loader_data = class_loader_data(class_loader); 2309 2310 { 2311 MutexLocker mu1(SystemDictionary_lock, THREAD); 2312 2313 // See whether biased locking is enabled and if so set it for this 2314 // klass. 2315 // Note that this must be done past the last potential blocking 2316 // point / safepoint. We enable biased locking lazily using a 2317 // VM_Operation to iterate the SystemDictionary and installing the 2318 // biasable mark word into each InstanceKlass's prototype header. 2319 // To avoid race conditions where we accidentally miss enabling the 2320 // optimization for one class in the process of being added to the 2321 // dictionary, we must not safepoint after the test of 2322 // BiasedLocking::enabled(). 2323 if (UseBiasedLocking && BiasedLocking::enabled()) { 2324 // Set biased locking bit for all loaded classes; it will be 2325 // cleared if revocation occurs too often for this type 2326 // NOTE that we must only do this when the class is initally 2327 // defined, not each time it is referenced from a new class loader 2328 if (k->class_loader() == class_loader()) { 2329 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2330 } 2331 } 2332 2333 // Make a new system dictionary entry. 2334 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2335 if (sd_check == NULL) { 2336 dictionary()->add_klass(name, loader_data, k); 2337 notice_modification(); 2338 } 2339#ifdef ASSERT 2340 sd_check = find_class(d_index, d_hash, name, loader_data); 2341 assert (sd_check != NULL, "should have entry in system dictionary"); 2342 // Note: there may be a placeholder entry: for circularity testing 2343 // or for parallel defines 2344#endif 2345 SystemDictionary_lock->notify_all(); 2346 } 2347} 2348 2349 2350// Try to find a class name using the loader constraints. The 2351// loader constraints might know about a class that isn't fully loaded 2352// yet and these will be ignored. 2353Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2354 Symbol* class_name, Handle class_loader, TRAPS) { 2355 2356 // First see if it has been loaded directly. 2357 // Force the protection domain to be null. (This removes protection checks.) 2358 Handle no_protection_domain; 2359 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2360 no_protection_domain, CHECK_NULL); 2361 if (klass != NULL) 2362 return klass; 2363 2364 // Now look to see if it has been loaded elsewhere, and is subject to 2365 // a loader constraint that would require this loader to return the 2366 // klass that is already loaded. 2367 if (FieldType::is_array(class_name)) { 2368 // For array classes, their Klass*s are not kept in the 2369 // constraint table. The element Klass*s are. 2370 FieldArrayInfo fd; 2371 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2372 if (t != T_OBJECT) { 2373 klass = Universe::typeArrayKlassObj(t); 2374 } else { 2375 MutexLocker mu(SystemDictionary_lock, THREAD); 2376 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2377 } 2378 // If element class already loaded, allocate array klass 2379 if (klass != NULL) { 2380 klass = klass->array_klass_or_null(fd.dimension()); 2381 } 2382 } else { 2383 MutexLocker mu(SystemDictionary_lock, THREAD); 2384 // Non-array classes are easy: simply check the constraint table. 2385 klass = constraints()->find_constrained_klass(class_name, class_loader); 2386 } 2387 2388 return klass; 2389} 2390 2391 2392bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2393 Handle class_loader1, 2394 Handle class_loader2, 2395 Thread* THREAD) { 2396 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2397 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2398 2399 Symbol* constraint_name = NULL; 2400 if (!FieldType::is_array(class_name)) { 2401 constraint_name = class_name; 2402 } else { 2403 // For array classes, their Klass*s are not kept in the 2404 // constraint table. The element classes are. 2405 FieldArrayInfo fd; 2406 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2407 // primitive types always pass 2408 if (t != T_OBJECT) { 2409 return true; 2410 } else { 2411 constraint_name = fd.object_key(); 2412 } 2413 } 2414 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2415 int d_index1 = dictionary()->hash_to_index(d_hash1); 2416 2417 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2418 int d_index2 = dictionary()->hash_to_index(d_hash2); 2419 { 2420 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2421 2422 // Better never do a GC while we're holding these oops 2423 NoSafepointVerifier nosafepoint; 2424 2425 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2426 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2427 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2428 klass2, class_loader2); 2429 } 2430} 2431 2432// Add entry to resolution error table to record the error when the first 2433// attempt to resolve a reference to a class has failed. 2434void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, 2435 Symbol* error, Symbol* message) { 2436 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2437 int index = resolution_errors()->hash_to_index(hash); 2438 { 2439 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2440 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2441 } 2442} 2443 2444// Delete a resolution error for RedefineClasses for a constant pool is going away 2445void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2446 resolution_errors()->delete_entry(pool); 2447} 2448 2449// Lookup resolution error table. Returns error if found, otherwise NULL. 2450Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, 2451 Symbol** message) { 2452 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2453 int index = resolution_errors()->hash_to_index(hash); 2454 { 2455 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2456 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2457 if (entry != NULL) { 2458 *message = entry->message(); 2459 return entry->error(); 2460 } else { 2461 return NULL; 2462 } 2463 } 2464} 2465 2466 2467// Signature constraints ensure that callers and callees agree about 2468// the meaning of type names in their signatures. This routine is the 2469// intake for constraints. It collects them from several places: 2470// 2471// * LinkResolver::resolve_method (if check_access is true) requires 2472// that the resolving class (the caller) and the defining class of 2473// the resolved method (the callee) agree on each type in the 2474// method's signature. 2475// 2476// * LinkResolver::resolve_interface_method performs exactly the same 2477// checks. 2478// 2479// * LinkResolver::resolve_field requires that the constant pool 2480// attempting to link to a field agree with the field's defining 2481// class about the type of the field signature. 2482// 2483// * klassVtable::initialize_vtable requires that, when a class 2484// overrides a vtable entry allocated by a superclass, that the 2485// overriding method (i.e., the callee) agree with the superclass 2486// on each type in the method's signature. 2487// 2488// * klassItable::initialize_itable requires that, when a class fills 2489// in its itables, for each non-abstract method installed in an 2490// itable, the method (i.e., the callee) agree with the interface 2491// on each type in the method's signature. 2492// 2493// All those methods have a boolean (check_access, checkconstraints) 2494// which turns off the checks. This is used from specialized contexts 2495// such as bootstrapping, dumping, and debugging. 2496// 2497// No direct constraint is placed between the class and its 2498// supertypes. Constraints are only placed along linked relations 2499// between callers and callees. When a method overrides or implements 2500// an abstract method in a supertype (superclass or interface), the 2501// constraints are placed as if the supertype were the caller to the 2502// overriding method. (This works well, since callers to the 2503// supertype have already established agreement between themselves and 2504// the supertype.) As a result of all this, a class can disagree with 2505// its supertype about the meaning of a type name, as long as that 2506// class neither calls a relevant method of the supertype, nor is 2507// called (perhaps via an override) from the supertype. 2508// 2509// 2510// SystemDictionary::check_signature_loaders(sig, l1, l2) 2511// 2512// Make sure all class components (including arrays) in the given 2513// signature will be resolved to the same class in both loaders. 2514// Returns the name of the type that failed a loader constraint check, or 2515// NULL if no constraint failed. No exception except OOME is thrown. 2516// Arrays are not added to the loader constraint table, their elements are. 2517Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2518 Handle loader1, Handle loader2, 2519 bool is_method, TRAPS) { 2520 // Nothing to do if loaders are the same. 2521 if (loader1() == loader2()) { 2522 return NULL; 2523 } 2524 2525 SignatureStream sig_strm(signature, is_method); 2526 while (!sig_strm.is_done()) { 2527 if (sig_strm.is_object()) { 2528 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2529 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2530 return sig; 2531 } 2532 } 2533 sig_strm.next(); 2534 } 2535 return NULL; 2536} 2537 2538 2539methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2540 Symbol* signature, 2541 TRAPS) { 2542 methodHandle empty; 2543 assert(MethodHandles::is_signature_polymorphic(iid) && 2544 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2545 iid != vmIntrinsics::_invokeGeneric, 2546 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); 2547 2548 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2549 int index = invoke_method_table()->hash_to_index(hash); 2550 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2551 methodHandle m; 2552 if (spe == NULL || spe->method() == NULL) { 2553 spe = NULL; 2554 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2555 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2556 if (!Arguments::is_interpreter_only()) { 2557 // Generate a compiled form of the MH intrinsic. 2558 AdapterHandlerLibrary::create_native_wrapper(m); 2559 // Check if have the compiled code. 2560 if (!m->has_compiled_code()) { 2561 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2562 "Out of space in CodeCache for method handle intrinsic", empty); 2563 } 2564 } 2565 // Now grab the lock. We might have to throw away the new method, 2566 // if a racing thread has managed to install one at the same time. 2567 { 2568 MutexLocker ml(SystemDictionary_lock, THREAD); 2569 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2570 if (spe == NULL) 2571 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2572 if (spe->method() == NULL) 2573 spe->set_method(m()); 2574 } 2575 } 2576 2577 assert(spe != NULL && spe->method() != NULL, ""); 2578 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2579 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2580 "MH intrinsic invariant"); 2581 return spe->method(); 2582} 2583 2584// Helper for unpacking the return value from linkMethod and linkCallSite. 2585static methodHandle unpack_method_and_appendix(Handle mname, 2586 KlassHandle accessing_klass, 2587 objArrayHandle appendix_box, 2588 Handle* appendix_result, 2589 TRAPS) { 2590 methodHandle empty; 2591 if (mname.not_null()) { 2592 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2593 if (vmtarget != NULL && vmtarget->is_method()) { 2594 Method* m = (Method*)vmtarget; 2595 oop appendix = appendix_box->obj_at(0); 2596 if (TraceMethodHandles) { 2597 #ifndef PRODUCT 2598 ttyLocker ttyl; 2599 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2600 m->print(); 2601 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2602 tty->cr(); 2603 #endif //PRODUCT 2604 } 2605 (*appendix_result) = Handle(THREAD, appendix); 2606 // the target is stored in the cpCache and if a reference to this 2607 // MethodName is dropped we need a way to make sure the 2608 // class_loader containing this method is kept alive. 2609 // FIXME: the appendix might also preserve this dependency. 2610 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2611 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2612 return methodHandle(THREAD, m); 2613 } 2614 } 2615 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2616 return empty; 2617} 2618 2619methodHandle SystemDictionary::find_method_handle_invoker(KlassHandle klass, 2620 Symbol* name, 2621 Symbol* signature, 2622 KlassHandle accessing_klass, 2623 Handle *appendix_result, 2624 Handle *method_type_result, 2625 TRAPS) { 2626 methodHandle empty; 2627 assert(THREAD->can_call_java() ,""); 2628 Handle method_type = 2629 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2630 2631 int ref_kind = JVM_REF_invokeVirtual; 2632 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2633 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2634 assert(appendix_box->obj_at(0) == NULL, ""); 2635 2636 // This should not happen. JDK code should take care of that. 2637 if (accessing_klass.is_null() || method_type.is_null()) { 2638 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2639 } 2640 2641 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2642 JavaCallArguments args; 2643 args.push_oop(accessing_klass()->java_mirror()); 2644 args.push_int(ref_kind); 2645 args.push_oop(klass()->java_mirror()); 2646 args.push_oop(name_str()); 2647 args.push_oop(method_type()); 2648 args.push_oop(appendix_box()); 2649 JavaValue result(T_OBJECT); 2650 JavaCalls::call_static(&result, 2651 SystemDictionary::MethodHandleNatives_klass(), 2652 vmSymbols::linkMethod_name(), 2653 vmSymbols::linkMethod_signature(), 2654 &args, CHECK_(empty)); 2655 Handle mname(THREAD, (oop) result.get_jobject()); 2656 (*method_type_result) = method_type; 2657 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2658} 2659 2660// Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2661// We must ensure that all class loaders everywhere will reach this class, for any client. 2662// This is a safe bet for public classes in java.lang, such as Object and String. 2663// We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2664// Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2665static bool is_always_visible_class(oop mirror) { 2666 Klass* klass = java_lang_Class::as_Klass(mirror); 2667 if (klass->is_objArray_klass()) { 2668 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2669 } 2670 if (klass->is_typeArray_klass()) { 2671 return true; // primitive array 2672 } 2673 assert(klass->is_instance_klass(), "%s", klass->external_name()); 2674 return klass->is_public() && 2675 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2676 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2677} 2678 2679// Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2680// signature, as interpreted relative to the given class loader. 2681// Because of class loader constraints, all method handle usage must be 2682// consistent with this loader. 2683Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2684 KlassHandle accessing_klass, 2685 TRAPS) { 2686 Handle empty; 2687 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2688 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2689 int index = invoke_method_table()->hash_to_index(hash); 2690 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2691 if (spe != NULL && spe->method_type() != NULL) { 2692 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2693 return Handle(THREAD, spe->method_type()); 2694 } else if (!THREAD->can_call_java()) { 2695 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2696 return Handle(); // do not attempt from within compiler, unless it was cached 2697 } 2698 2699 Handle class_loader, protection_domain; 2700 if (accessing_klass.not_null()) { 2701 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2702 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2703 } 2704 bool can_be_cached = true; 2705 int npts = ArgumentCount(signature).size(); 2706 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2707 int arg = 0; 2708 Handle rt; // the return type from the signature 2709 ResourceMark rm(THREAD); 2710 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2711 oop mirror = NULL; 2712 if (can_be_cached) { 2713 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2714 mirror = ss.as_java_mirror(Handle(), Handle(), 2715 SignatureStream::ReturnNull, CHECK_(empty)); 2716 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2717 // Fall back to accessing_klass context. 2718 can_be_cached = false; 2719 } 2720 } 2721 if (!can_be_cached) { 2722 // Resolve, throwing a real error if it doesn't work. 2723 mirror = ss.as_java_mirror(class_loader, protection_domain, 2724 SignatureStream::NCDFError, CHECK_(empty)); 2725 } 2726 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string()); 2727 if (ss.at_return_type()) 2728 rt = Handle(THREAD, mirror); 2729 else 2730 pts->obj_at_put(arg++, mirror); 2731 2732 // Check accessibility. 2733 if (ss.is_object() && accessing_klass.not_null()) { 2734 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2735 mirror = NULL; // safety 2736 // Emulate ConstantPool::verify_constant_pool_resolve. 2737 if (sel_klass->is_objArray_klass()) 2738 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2739 if (sel_klass->is_instance_klass()) { 2740 KlassHandle sel_kh(THREAD, sel_klass); 2741 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2742 } 2743 } 2744 } 2745 assert(arg == npts, ""); 2746 2747 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType 2748 JavaCallArguments args(Handle(THREAD, rt())); 2749 args.push_oop(pts()); 2750 JavaValue result(T_OBJECT); 2751 JavaCalls::call_static(&result, 2752 SystemDictionary::MethodHandleNatives_klass(), 2753 vmSymbols::findMethodHandleType_name(), 2754 vmSymbols::findMethodHandleType_signature(), 2755 &args, CHECK_(empty)); 2756 Handle method_type(THREAD, (oop) result.get_jobject()); 2757 2758 if (can_be_cached) { 2759 // We can cache this MethodType inside the JVM. 2760 MutexLocker ml(SystemDictionary_lock, THREAD); 2761 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2762 if (spe == NULL) 2763 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2764 if (spe->method_type() == NULL) { 2765 spe->set_method_type(method_type()); 2766 } 2767 } 2768 2769 // report back to the caller with the MethodType 2770 return method_type; 2771} 2772 2773// Ask Java code to find or construct a method handle constant. 2774Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2775 int ref_kind, //e.g., JVM_REF_invokeVirtual 2776 KlassHandle callee, 2777 Symbol* name_sym, 2778 Symbol* signature, 2779 TRAPS) { 2780 Handle empty; 2781 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2782 Handle type; 2783 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2784 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2785 } else if (caller.is_null()) { 2786 // This should not happen. JDK code should take care of that. 2787 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2788 } else { 2789 ResourceMark rm(THREAD); 2790 SignatureStream ss(signature, false); 2791 if (!ss.is_done()) { 2792 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2793 SignatureStream::NCDFError, CHECK_(empty)); 2794 type = Handle(THREAD, mirror); 2795 ss.next(); 2796 if (!ss.is_done()) type = Handle(); // error! 2797 } 2798 } 2799 if (type.is_null()) { 2800 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2801 } 2802 2803 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2804 JavaCallArguments args; 2805 args.push_oop(caller->java_mirror()); // the referring class 2806 args.push_int(ref_kind); 2807 args.push_oop(callee->java_mirror()); // the target class 2808 args.push_oop(name()); 2809 args.push_oop(type()); 2810 JavaValue result(T_OBJECT); 2811 JavaCalls::call_static(&result, 2812 SystemDictionary::MethodHandleNatives_klass(), 2813 vmSymbols::linkMethodHandleConstant_name(), 2814 vmSymbols::linkMethodHandleConstant_signature(), 2815 &args, CHECK_(empty)); 2816 return Handle(THREAD, (oop) result.get_jobject()); 2817} 2818 2819// Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2820// name and signature, as interpreted relative to the given class loader. 2821methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2822 Handle bootstrap_specifier, 2823 Symbol* name, 2824 Symbol* type, 2825 Handle *appendix_result, 2826 Handle *method_type_result, 2827 TRAPS) { 2828 methodHandle empty; 2829 Handle bsm, info; 2830 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2831 bsm = bootstrap_specifier; 2832 } else { 2833 assert(bootstrap_specifier->is_objArray(), ""); 2834 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2835 int len = args->length(); 2836 assert(len >= 1, ""); 2837 bsm = Handle(THREAD, args->obj_at(0)); 2838 if (len > 1) { 2839 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2840 for (int i = 1; i < len; i++) 2841 args1->obj_at_put(i-1, args->obj_at(i)); 2842 info = Handle(THREAD, args1); 2843 } 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.is_null() || method_type.is_null()) { 2853 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2854 } 2855 2856 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2857 assert(appendix_box->obj_at(0) == NULL, ""); 2858 2859 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2860 JavaCallArguments args; 2861 args.push_oop(caller->java_mirror()); 2862 args.push_oop(bsm()); 2863 args.push_oop(method_name()); 2864 args.push_oop(method_type()); 2865 args.push_oop(info()); 2866 args.push_oop(appendix_box); 2867 JavaValue result(T_OBJECT); 2868 JavaCalls::call_static(&result, 2869 SystemDictionary::MethodHandleNatives_klass(), 2870 vmSymbols::linkCallSite_name(), 2871 vmSymbols::linkCallSite_signature(), 2872 &args, CHECK_(empty)); 2873 Handle mname(THREAD, (oop) result.get_jobject()); 2874 (*method_type_result) = method_type; 2875 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2876} 2877 2878// Since the identity hash code for symbols changes when the symbols are 2879// moved from the regular perm gen (hash in the mark word) to the shared 2880// spaces (hash is the address), the classes loaded into the dictionary 2881// may be in the wrong buckets. 2882 2883void SystemDictionary::reorder_dictionary() { 2884 dictionary()->reorder_dictionary(); 2885} 2886 2887 2888void SystemDictionary::copy_buckets(char** top, char* end) { 2889 dictionary()->copy_buckets(top, end); 2890} 2891 2892 2893void SystemDictionary::copy_table(char** top, char* end) { 2894 dictionary()->copy_table(top, end); 2895} 2896 2897 2898void SystemDictionary::reverse() { 2899 dictionary()->reverse(); 2900} 2901 2902int SystemDictionary::number_of_classes() { 2903 return dictionary()->number_of_entries(); 2904} 2905 2906 2907// ---------------------------------------------------------------------------- 2908void SystemDictionary::print_shared(bool details) { 2909 shared_dictionary()->print(details); 2910} 2911 2912void SystemDictionary::print(bool details) { 2913 dictionary()->print(details); 2914 2915 // Placeholders 2916 GCMutexLocker mu(SystemDictionary_lock); 2917 placeholders()->print(); 2918 2919 // loader constraints - print under SD_lock 2920 constraints()->print(); 2921} 2922 2923 2924void SystemDictionary::verify() { 2925 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2926 guarantee(constraints() != NULL, 2927 "Verify of loader constraints failed"); 2928 guarantee(dictionary()->number_of_entries() >= 0 && 2929 placeholders()->number_of_entries() >= 0, 2930 "Verify of system dictionary failed"); 2931 2932 // Verify dictionary 2933 dictionary()->verify(); 2934 2935 GCMutexLocker mu(SystemDictionary_lock); 2936 placeholders()->verify(); 2937 2938 // Verify constraint table 2939 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2940 constraints()->verify(dictionary(), placeholders()); 2941} 2942 2943// caller needs ResourceMark 2944const char* SystemDictionary::loader_name(const oop loader) { 2945 return ((loader) == NULL ? "<bootloader>" : 2946 InstanceKlass::cast((loader)->klass())->name()->as_C_string()); 2947} 2948 2949// caller needs ResourceMark 2950const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { 2951 return (loader_data->class_loader() == NULL ? "<bootloader>" : 2952 InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string()); 2953} 2954