1 /* 2 * Copyright (c) 1997, 2014, 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/classLoaderData.inline.hpp" 27 #include "classfile/dictionary.hpp" 28 #include "classfile/javaClasses.hpp" 29 #include "classfile/loaderConstraints.hpp" 30 #include "classfile/placeholders.hpp" 31 #include "classfile/resolutionErrors.hpp" 32 #include "classfile/stringTable.hpp" 33 #include "classfile/systemDictionary.hpp" 34 #include "classfile/vmSymbols.hpp" 35 #include "compiler/compileBroker.hpp" 36 #include "interpreter/bytecodeStream.hpp" 37 #include "interpreter/interpreter.hpp" 38 #include "memory/gcLocker.hpp" 39 #include "memory/oopFactory.hpp" 40 #include "oops/instanceKlass.hpp" 41 #include "oops/instanceRefKlass.hpp" 42 #include "oops/klass.inline.hpp" 43 #include "oops/methodData.hpp" 44 #include "oops/objArrayKlass.hpp" 45 #include "oops/oop.inline.hpp" 46 #include "oops/oop.inline2.hpp" 47 #include "oops/typeArrayKlass.hpp" 48 #include "prims/jvmtiEnvBase.hpp" 49 #include "prims/methodHandles.hpp" 50 #include "runtime/biasedLocking.hpp" 51 #include "runtime/fieldType.hpp" 52 #include "runtime/handles.inline.hpp" 53 #include "runtime/java.hpp" 54 #include "runtime/javaCalls.hpp" 55 #include "runtime/mutexLocker.hpp" 56 #include "runtime/orderAccess.inline.hpp" 57 #include "runtime/signature.hpp" 58 #include "services/classLoadingService.hpp" 59 #include "services/threadService.hpp" 60 #include "utilities/macros.hpp" 61 #include "utilities/ticks.hpp" 62 63 #if INCLUDE_TRACE 64 #include "trace/tracing.hpp" 65 #endif 66 67 Dictionary* SystemDictionary::_dictionary = NULL; 68 PlaceholderTable* SystemDictionary::_placeholders = NULL; 69 Dictionary* SystemDictionary::_shared_dictionary = NULL; 70 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 71 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 72 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 73 74 75 int SystemDictionary::_number_of_modifications = 0; 76 int SystemDictionary::_sdgeneration = 0; 77 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 78 20201,40423,99991}; 79 80 oop SystemDictionary::_system_loader_lock_obj = NULL; 81 82 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 83 = { NULL /*, NULL...*/ }; 84 85 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 86 87 oop SystemDictionary::_java_system_loader = NULL; 88 89 bool SystemDictionary::_has_loadClassInternal = false; 90 bool SystemDictionary::_has_checkPackageAccess = false; 91 92 // lazily initialized klass variables 93 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 94 95 96 // ---------------------------------------------------------------------------- 97 // Java-level SystemLoader 98 99 oop SystemDictionary::java_system_loader() { 100 return _java_system_loader; 101 } 102 103 void SystemDictionary::compute_java_system_loader(TRAPS) { 104 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 105 JavaValue result(T_OBJECT); 106 JavaCalls::call_static(&result, 107 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 108 vmSymbols::getSystemClassLoader_name(), 109 vmSymbols::void_classloader_signature(), 110 CHECK); 111 112 _java_system_loader = (oop)result.get_jobject(); 113 } 114 115 116 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 117 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 118 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL); 119 } 120 121 // ---------------------------------------------------------------------------- 122 // debugging 123 124 #ifdef ASSERT 125 126 // return true if class_name contains no '.' (internal format is '/') 127 bool SystemDictionary::is_internal_format(Symbol* class_name) { 128 if (class_name != NULL) { 129 ResourceMark rm; 130 char* name = class_name->as_C_string(); 131 return strchr(name, '.') == NULL; 132 } else { 133 return true; 134 } 135 } 136 137 #endif 138 139 // ---------------------------------------------------------------------------- 140 // Parallel class loading check 141 142 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 143 if (UnsyncloadClass || class_loader.is_null()) return true; 144 if (AlwaysLockClassLoader) return false; 145 return java_lang_ClassLoader::parallelCapable(class_loader()); 146 } 147 // ---------------------------------------------------------------------------- 148 // ParallelDefineClass flag does not apply to bootclass loader 149 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 150 if (class_loader.is_null()) return false; 151 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 152 return true; 153 } 154 return false; 155 } 156 157 /** 158 * Returns true if the passed class loader is the extension class loader. 159 */ 160 bool SystemDictionary::is_ext_class_loader(Handle class_loader) { 161 if (class_loader.is_null()) { 162 return false; 163 } 164 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader()); 165 } 166 167 // ---------------------------------------------------------------------------- 168 // Resolving of classes 169 170 // Forwards to resolve_or_null 171 172 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 173 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 174 if (HAS_PENDING_EXCEPTION || klass == NULL) { 175 KlassHandle k_h(THREAD, klass); 176 // can return a null klass 177 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD); 178 } 179 return klass; 180 } 181 182 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 183 bool throw_error, 184 KlassHandle klass_h, TRAPS) { 185 if (HAS_PENDING_EXCEPTION) { 186 // If we have a pending exception we forward it to the caller, unless throw_error is true, 187 // in which case we have to check whether the pending exception is a ClassNotFoundException, 188 // and if so convert it to a NoClassDefFoundError 189 // And chain the original ClassNotFoundException 190 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 191 ResourceMark rm(THREAD); 192 assert(klass_h() == NULL, "Should not have result with exception pending"); 193 Handle e(THREAD, PENDING_EXCEPTION); 194 CLEAR_PENDING_EXCEPTION; 195 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 196 } else { 197 return NULL; 198 } 199 } 200 // Class not found, throw appropriate error or exception depending on value of throw_error 201 if (klass_h() == NULL) { 202 ResourceMark rm(THREAD); 203 if (throw_error) { 204 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 205 } else { 206 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 207 } 208 } 209 return (Klass*)klass_h(); 210 } 211 212 213 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 214 bool throw_error, TRAPS) 215 { 216 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 217 } 218 219 220 // Forwards to resolve_instance_class_or_null 221 222 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 223 assert(!THREAD->is_Compiler_thread(), 224 err_msg("can not load classes with compiler thread: class=%s, classloader=%s", 225 class_name->as_C_string(), 226 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string())); 227 if (FieldType::is_array(class_name)) { 228 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 229 } else if (FieldType::is_obj(class_name)) { 230 ResourceMark rm(THREAD); 231 // Ignore wrapping L and ;. 232 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 233 class_name->utf8_length() - 2, CHECK_NULL); 234 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL); 235 } else { 236 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 237 } 238 } 239 240 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 241 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 242 } 243 244 // Forwards to resolve_instance_class_or_null 245 246 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 247 Handle class_loader, 248 Handle protection_domain, 249 TRAPS) { 250 assert(FieldType::is_array(class_name), "must be array"); 251 Klass* k = NULL; 252 FieldArrayInfo fd; 253 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 254 // of this call 255 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 256 if (t == T_OBJECT) { 257 // naked oop "k" is OK here -- we assign back into it 258 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 259 class_loader, 260 protection_domain, 261 CHECK_NULL); 262 if (k != NULL) { 263 k = k->array_klass(fd.dimension(), CHECK_NULL); 264 } 265 } else { 266 k = Universe::typeArrayKlassObj(t); 267 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 268 } 269 return k; 270 } 271 272 273 // Must be called for any super-class or super-interface resolution 274 // during class definition to allow class circularity checking 275 // super-interface callers: 276 // parse_interfaces - for defineClass & jvmtiRedefineClasses 277 // super-class callers: 278 // ClassFileParser - for defineClass & jvmtiRedefineClasses 279 // load_shared_class - while loading a class from shared archive 280 // resolve_instance_class_or_null: 281 // via: handle_parallel_super_load 282 // when resolving a class that has an existing placeholder with 283 // a saved superclass [i.e. a defineClass is currently in progress] 284 // if another thread is trying to resolve the class, it must do 285 // super-class checks on its own thread to catch class circularity 286 // This last call is critical in class circularity checking for cases 287 // where classloading is delegated to different threads and the 288 // classloader lock is released. 289 // Take the case: Base->Super->Base 290 // 1. If thread T1 tries to do a defineClass of class Base 291 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 292 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 293 // so it tries to load Super 294 // 3. If we load the class internally, or user classloader uses same thread 295 // loadClassFromxxx or defineClass via parseClassFile Super ... 296 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 297 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 298 // 3.4 calls resolve_super_or_fail Base 299 // 3.5 finds T1,Base -> throws class circularity 300 //OR 4. If T2 tries to resolve Super via defineClass Super ... 301 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 302 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 303 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 304 // 4.4 finds T2, Super -> throws class circularity 305 // Must be called, even if superclass is null, since this is 306 // where the placeholder entry is created which claims this 307 // thread is loading this class/classloader. 308 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 309 Symbol* class_name, 310 Handle class_loader, 311 Handle protection_domain, 312 bool is_superclass, 313 TRAPS) { 314 // Double-check, if child class is already loaded, just return super-class,interface 315 // Don't add a placedholder if already loaded, i.e. already in system dictionary 316 // Make sure there's a placeholder for the *child* before resolving. 317 // Used as a claim that this thread is currently loading superclass/classloader 318 // Used here for ClassCircularity checks and also for heap verification 319 // (every InstanceKlass in the heap needs to be in the system dictionary 320 // or have a placeholder). 321 // Must check ClassCircularity before checking if super class is already loaded 322 // 323 // We might not already have a placeholder if this child_name was 324 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 325 // the name of the class might not be known until the stream is actually 326 // parsed. 327 // Bugs 4643874, 4715493 328 // compute_hash can have a safepoint 329 330 ClassLoaderData* loader_data = class_loader_data(class_loader); 331 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 332 int d_index = dictionary()->hash_to_index(d_hash); 333 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 334 int p_index = placeholders()->hash_to_index(p_hash); 335 // can't throw error holding a lock 336 bool child_already_loaded = false; 337 bool throw_circularity_error = false; 338 { 339 MutexLocker mu(SystemDictionary_lock, THREAD); 340 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 341 Klass* quicksuperk; 342 // to support // loading: if child done loading, just return superclass 343 // if class_name, & class_loader don't match: 344 // if initial define, SD update will give LinkageError 345 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 346 // so we don't throw an exception here. 347 // see: nsk redefclass014 & java.lang.instrument Instrument032 348 if ((childk != NULL ) && (is_superclass) && 349 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) && 350 351 ((quicksuperk->name() == class_name) && 352 (quicksuperk->class_loader() == class_loader()))) { 353 return quicksuperk; 354 } else { 355 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 356 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 357 throw_circularity_error = true; 358 } 359 } 360 if (!throw_circularity_error) { 361 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 362 } 363 } 364 if (throw_circularity_error) { 365 ResourceMark rm(THREAD); 366 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 367 } 368 369 // java.lang.Object should have been found above 370 assert(class_name != NULL, "null super class for resolving"); 371 // Resolve the super class or interface, check results on return 372 Klass* superk = SystemDictionary::resolve_or_null(class_name, 373 class_loader, 374 protection_domain, 375 THREAD); 376 377 KlassHandle superk_h(THREAD, superk); 378 379 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 380 // It is no longer necessary to keep the placeholder table alive until update_dictionary 381 // or error. GC used to walk the placeholder table as strong roots. 382 // The instanceKlass is kept alive because the class loader is on the stack, 383 // which keeps the loader_data alive, as well as all instanceKlasses in 384 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 385 { 386 MutexLocker mu(SystemDictionary_lock, THREAD); 387 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 388 SystemDictionary_lock->notify_all(); 389 } 390 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 391 // can null superk 392 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD)); 393 } 394 395 return superk_h(); 396 } 397 398 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 399 Handle class_loader, 400 Handle protection_domain, 401 TRAPS) { 402 if(!has_checkPackageAccess()) return; 403 404 // Now we have to call back to java to check if the initating class has access 405 JavaValue result(T_VOID); 406 if (TraceProtectionDomainVerification) { 407 // Print out trace information 408 tty->print_cr("Checking package access"); 409 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); 410 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); 411 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); 412 } 413 414 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 415 JavaCalls::call_special(&result, 416 class_loader, 417 system_loader, 418 vmSymbols::checkPackageAccess_name(), 419 vmSymbols::class_protectiondomain_signature(), 420 Handle(THREAD, klass->java_mirror()), 421 protection_domain, 422 THREAD); 423 424 if (TraceProtectionDomainVerification) { 425 if (HAS_PENDING_EXCEPTION) { 426 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); 427 } else { 428 tty->print_cr(" -> granted"); 429 } 430 tty->cr(); 431 } 432 433 if (HAS_PENDING_EXCEPTION) return; 434 435 // If no exception has been thrown, we have validated the protection domain 436 // Insert the protection domain of the initiating class into the set. 437 { 438 // We recalculate the entry here -- we've called out to java since 439 // the last time it was calculated. 440 ClassLoaderData* loader_data = class_loader_data(class_loader); 441 442 Symbol* kn = klass->name(); 443 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 444 int d_index = dictionary()->hash_to_index(d_hash); 445 446 MutexLocker mu(SystemDictionary_lock, THREAD); 447 { 448 // Note that we have an entry, and entries can be deleted only during GC, 449 // so we cannot allow GC to occur while we're holding this entry. 450 451 // We're using a No_Safepoint_Verifier to catch any place where we 452 // might potentially do a GC at all. 453 // Dictionary::do_unloading() asserts that classes in SD are only 454 // unloaded at a safepoint. Anonymous classes are not in SD. 455 No_Safepoint_Verifier nosafepoint; 456 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 457 protection_domain, THREAD); 458 } 459 } 460 } 461 462 // We only get here if this thread finds that another thread 463 // has already claimed the placeholder token for the current operation, 464 // but that other thread either never owned or gave up the 465 // object lock 466 // Waits on SystemDictionary_lock to indicate placeholder table updated 467 // On return, caller must recheck placeholder table state 468 // 469 // We only get here if 470 // 1) custom classLoader, i.e. not bootstrap classloader 471 // 2) UnsyncloadClass not set 472 // 3) custom classLoader has broken the class loader objectLock 473 // so another thread got here in parallel 474 // 475 // lockObject must be held. 476 // Complicated dance due to lock ordering: 477 // Must first release the classloader object lock to 478 // allow initial definer to complete the class definition 479 // and to avoid deadlock 480 // Reclaim classloader lock object with same original recursion count 481 // Must release SystemDictionary_lock after notify, since 482 // class loader lock must be claimed before SystemDictionary_lock 483 // to prevent deadlocks 484 // 485 // The notify allows applications that did an untimed wait() on 486 // the classloader object lock to not hang. 487 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 488 assert_lock_strong(SystemDictionary_lock); 489 490 bool calledholdinglock 491 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 492 assert(calledholdinglock,"must hold lock for notify"); 493 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 494 ObjectSynchronizer::notifyall(lockObject, THREAD); 495 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 496 SystemDictionary_lock->wait(); 497 SystemDictionary_lock->unlock(); 498 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 499 SystemDictionary_lock->lock(); 500 } 501 502 // If the class in is in the placeholder table, class loading is in progress 503 // For cases where the application changes threads to load classes, it 504 // is critical to ClassCircularity detection that we try loading 505 // the superclass on the same thread internally, so we do parallel 506 // super class loading here. 507 // This also is critical in cases where the original thread gets stalled 508 // even in non-circularity situations. 509 // Note: must call resolve_super_or_fail even if null super - 510 // to force placeholder entry creation for this class for circularity detection 511 // Caller must check for pending exception 512 // Returns non-null Klass* if other thread has completed load 513 // and we are done, 514 // If return null Klass* and no pending exception, the caller must load the class 515 instanceKlassHandle SystemDictionary::handle_parallel_super_load( 516 Symbol* name, Symbol* superclassname, Handle class_loader, 517 Handle protection_domain, Handle lockObject, TRAPS) { 518 519 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 520 ClassLoaderData* loader_data = class_loader_data(class_loader); 521 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 522 int d_index = dictionary()->hash_to_index(d_hash); 523 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 524 int p_index = placeholders()->hash_to_index(p_hash); 525 526 // superk is not used, resolve_super called for circularity check only 527 // This code is reached in two situations. One if this thread 528 // is loading the same class twice (e.g. ClassCircularity, or 529 // java.lang.instrument). 530 // The second is if another thread started the resolve_super first 531 // and has not yet finished. 532 // In both cases the original caller will clean up the placeholder 533 // entry on error. 534 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 535 superclassname, 536 class_loader, 537 protection_domain, 538 true, 539 CHECK_(nh)); 540 541 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 542 // Serial class loaders and bootstrap classloader do wait for superclass loads 543 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 544 MutexLocker mu(SystemDictionary_lock, THREAD); 545 // Check if classloading completed while we were loading superclass or waiting 546 Klass* check = find_class(d_index, d_hash, name, loader_data); 547 if (check != NULL) { 548 // Klass is already loaded, so just return it 549 return(instanceKlassHandle(THREAD, check)); 550 } else { 551 return nh; 552 } 553 } 554 555 // must loop to both handle other placeholder updates 556 // and spurious notifications 557 bool super_load_in_progress = true; 558 PlaceholderEntry* placeholder; 559 while (super_load_in_progress) { 560 MutexLocker mu(SystemDictionary_lock, THREAD); 561 // Check if classloading completed while we were loading superclass or waiting 562 Klass* check = find_class(d_index, d_hash, name, loader_data); 563 if (check != NULL) { 564 // Klass is already loaded, so just return it 565 return(instanceKlassHandle(THREAD, check)); 566 } else { 567 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 568 if (placeholder && placeholder->super_load_in_progress() ){ 569 // Before UnsyncloadClass: 570 // We only get here if the application has released the 571 // classloader lock when another thread was in the middle of loading a 572 // superclass/superinterface for this class, and now 573 // this thread is also trying to load this class. 574 // To minimize surprises, the first thread that started to 575 // load a class should be the one to complete the loading 576 // with the classfile it initially expected. 577 // This logic has the current thread wait once it has done 578 // all the superclass/superinterface loading it can, until 579 // the original thread completes the class loading or fails 580 // If it completes we will use the resulting InstanceKlass 581 // which we will find below in the systemDictionary. 582 // We also get here for parallel bootstrap classloader 583 if (class_loader.is_null()) { 584 SystemDictionary_lock->wait(); 585 } else { 586 double_lock_wait(lockObject, THREAD); 587 } 588 } else { 589 // If not in SD and not in PH, other thread's load must have failed 590 super_load_in_progress = false; 591 } 592 } 593 } 594 return (nh); 595 } 596 597 598 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 599 Handle class_loader, 600 Handle protection_domain, 601 TRAPS) { 602 assert(name != NULL && !FieldType::is_array(name) && 603 !FieldType::is_obj(name), "invalid class name"); 604 605 Ticks class_load_start_time = Ticks::now(); 606 607 // Fix for 4474172; see evaluation for more details 608 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 609 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 610 611 // Do lookup to see if class already exist and the protection domain 612 // has the right access 613 // This call uses find which checks protection domain already matches 614 // All subsequent calls use find_class, and set has_loaded_class so that 615 // before we return a result we call out to java to check for valid protection domain 616 // to allow returning the Klass* and add it to the pd_set if it is valid 617 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 618 int d_index = dictionary()->hash_to_index(d_hash); 619 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 620 protection_domain, THREAD); 621 if (probe != NULL) return probe; 622 623 624 // Non-bootstrap class loaders will call out to class loader and 625 // define via jvm/jni_DefineClass which will acquire the 626 // class loader object lock to protect against multiple threads 627 // defining the class in parallel by accident. 628 // This lock must be acquired here so the waiter will find 629 // any successful result in the SystemDictionary and not attempt 630 // the define 631 // ParallelCapable Classloaders and the bootstrap classloader, 632 // or all classloaders with UnsyncloadClass do not acquire lock here 633 bool DoObjectLock = true; 634 if (is_parallelCapable(class_loader)) { 635 DoObjectLock = false; 636 } 637 638 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 639 int p_index = placeholders()->hash_to_index(p_hash); 640 641 // Class is not in SystemDictionary so we have to do loading. 642 // Make sure we are synchronized on the class loader before we proceed 643 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 644 check_loader_lock_contention(lockObject, THREAD); 645 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 646 647 // Check again (after locking) if class already exist in SystemDictionary 648 bool class_has_been_loaded = false; 649 bool super_load_in_progress = false; 650 bool havesupername = false; 651 instanceKlassHandle k; 652 PlaceholderEntry* placeholder; 653 Symbol* superclassname = NULL; 654 655 { 656 MutexLocker mu(SystemDictionary_lock, THREAD); 657 Klass* check = find_class(d_index, d_hash, name, loader_data); 658 if (check != NULL) { 659 // Klass is already loaded, so just return it 660 class_has_been_loaded = true; 661 k = instanceKlassHandle(THREAD, check); 662 } else { 663 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 664 if (placeholder && placeholder->super_load_in_progress()) { 665 super_load_in_progress = true; 666 if (placeholder->havesupername() == true) { 667 superclassname = placeholder->supername(); 668 havesupername = true; 669 } 670 } 671 } 672 } 673 674 // If the class is in the placeholder table, class loading is in progress 675 if (super_load_in_progress && havesupername==true) { 676 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 677 class_loader, protection_domain, lockObject, THREAD); 678 if (HAS_PENDING_EXCEPTION) { 679 return NULL; 680 } 681 if (!k.is_null()) { 682 class_has_been_loaded = true; 683 } 684 } 685 686 bool throw_circularity_error = false; 687 if (!class_has_been_loaded) { 688 bool load_instance_added = false; 689 690 // add placeholder entry to record loading instance class 691 // Five cases: 692 // All cases need to prevent modifying bootclasssearchpath 693 // in parallel with a classload of same classname 694 // Redefineclasses uses existence of the placeholder for the duration 695 // of the class load to prevent concurrent redefinition of not completely 696 // defined classes. 697 // case 1. traditional classloaders that rely on the classloader object lock 698 // - no other need for LOAD_INSTANCE 699 // case 2. traditional classloaders that break the classloader object lock 700 // as a deadlock workaround. Detection of this case requires that 701 // this check is done while holding the classloader object lock, 702 // and that lock is still held when calling classloader's loadClass. 703 // For these classloaders, we ensure that the first requestor 704 // completes the load and other requestors wait for completion. 705 // case 3. UnsyncloadClass - don't use objectLocker 706 // With this flag, we allow parallel classloading of a 707 // class/classloader pair 708 // case4. Bootstrap classloader - don't own objectLocker 709 // This classloader supports parallelism at the classloader level, 710 // but only allows a single load of a class/classloader pair. 711 // No performance benefit and no deadlock issues. 712 // case 5. parallelCapable user level classloaders - without objectLocker 713 // Allow parallel classloading of a class/classloader pair 714 715 { 716 MutexLocker mu(SystemDictionary_lock, THREAD); 717 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 718 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 719 if (oldprobe) { 720 // only need check_seen_thread once, not on each loop 721 // 6341374 java/lang/Instrument with -Xcomp 722 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 723 throw_circularity_error = true; 724 } else { 725 // case 1: traditional: should never see load_in_progress. 726 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 727 728 // case 4: bootstrap classloader: prevent futile classloading, 729 // wait on first requestor 730 if (class_loader.is_null()) { 731 SystemDictionary_lock->wait(); 732 } else { 733 // case 2: traditional with broken classloader lock. wait on first 734 // requestor. 735 double_lock_wait(lockObject, THREAD); 736 } 737 // Check if classloading completed while we were waiting 738 Klass* check = find_class(d_index, d_hash, name, loader_data); 739 if (check != NULL) { 740 // Klass is already loaded, so just return it 741 k = instanceKlassHandle(THREAD, check); 742 class_has_been_loaded = true; 743 } 744 // check if other thread failed to load and cleaned up 745 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 746 } 747 } 748 } 749 } 750 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 751 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 752 // LOAD_INSTANCE in parallel 753 754 if (!throw_circularity_error && !class_has_been_loaded) { 755 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 756 load_instance_added = true; 757 // For class loaders that do not acquire the classloader object lock, 758 // if they did not catch another thread holding LOAD_INSTANCE, 759 // need a check analogous to the acquire ObjectLocker/find_class 760 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 761 // one final check if the load has already completed 762 // class loaders holding the ObjectLock shouldn't find the class here 763 Klass* check = find_class(d_index, d_hash, name, loader_data); 764 if (check != NULL) { 765 // Klass is already loaded, so return it after checking/adding protection domain 766 k = instanceKlassHandle(THREAD, check); 767 class_has_been_loaded = true; 768 } 769 } 770 } 771 772 // must throw error outside of owning lock 773 if (throw_circularity_error) { 774 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 775 ResourceMark rm(THREAD); 776 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 777 } 778 779 if (!class_has_been_loaded) { 780 781 // Do actual loading 782 k = load_instance_class(name, class_loader, THREAD); 783 784 // For UnsyncloadClass only 785 // If they got a linkageError, check if a parallel class load succeeded. 786 // If it did, then for bytecode resolution the specification requires 787 // that we return the same result we did for the other thread, i.e. the 788 // successfully loaded InstanceKlass 789 // Should not get here for classloaders that support parallelism 790 // with the new cleaner mechanism, even with AllowParallelDefineClass 791 // Bootstrap goes through here to allow for an extra guarantee check 792 if (UnsyncloadClass || (class_loader.is_null())) { 793 if (k.is_null() && HAS_PENDING_EXCEPTION 794 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 795 MutexLocker mu(SystemDictionary_lock, THREAD); 796 Klass* check = find_class(d_index, d_hash, name, loader_data); 797 if (check != NULL) { 798 // Klass is already loaded, so just use it 799 k = instanceKlassHandle(THREAD, check); 800 CLEAR_PENDING_EXCEPTION; 801 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 802 } 803 } 804 } 805 806 // If everything was OK (no exceptions, no null return value), and 807 // class_loader is NOT the defining loader, do a little more bookkeeping. 808 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 809 k->class_loader() != class_loader()) { 810 811 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 812 813 // Need to check for a PENDING_EXCEPTION again; check_constraints 814 // can throw and doesn't use the CHECK macro. 815 if (!HAS_PENDING_EXCEPTION) { 816 { // Grabbing the Compile_lock prevents systemDictionary updates 817 // during compilations. 818 MutexLocker mu(Compile_lock, THREAD); 819 update_dictionary(d_index, d_hash, p_index, p_hash, 820 k, class_loader, THREAD); 821 } 822 823 if (JvmtiExport::should_post_class_load()) { 824 Thread *thread = THREAD; 825 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 826 JvmtiExport::post_class_load((JavaThread *) thread, k()); 827 } 828 } 829 } 830 } // load_instance_class loop 831 832 if (load_instance_added == true) { 833 // clean up placeholder entries for LOAD_INSTANCE success or error 834 // This brackets the SystemDictionary updates for both defining 835 // and initiating loaders 836 MutexLocker mu(SystemDictionary_lock, THREAD); 837 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 838 SystemDictionary_lock->notify_all(); 839 } 840 } 841 842 if (HAS_PENDING_EXCEPTION || k.is_null()) { 843 return NULL; 844 } 845 846 post_class_load_event(class_load_start_time, k, class_loader); 847 848 #ifdef ASSERT 849 { 850 ClassLoaderData* loader_data = k->class_loader_data(); 851 MutexLocker mu(SystemDictionary_lock, THREAD); 852 Klass* kk = find_class(name, loader_data); 853 assert(kk == k(), "should be present in dictionary"); 854 } 855 #endif 856 857 // return if the protection domain in NULL 858 if (protection_domain() == NULL) return k(); 859 860 // Check the protection domain has the right access 861 { 862 MutexLocker mu(SystemDictionary_lock, THREAD); 863 // Note that we have an entry, and entries can be deleted only during GC, 864 // so we cannot allow GC to occur while we're holding this entry. 865 // We're using a No_Safepoint_Verifier to catch any place where we 866 // might potentially do a GC at all. 867 // Dictionary::do_unloading() asserts that classes in SD are only 868 // unloaded at a safepoint. Anonymous classes are not in SD. 869 No_Safepoint_Verifier nosafepoint; 870 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 871 loader_data, 872 protection_domain)) { 873 return k(); 874 } 875 } 876 877 // Verify protection domain. If it fails an exception is thrown 878 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 879 880 return k(); 881 } 882 883 884 // This routine does not lock the system dictionary. 885 // 886 // Since readers don't hold a lock, we must make sure that system 887 // dictionary entries are only removed at a safepoint (when only one 888 // thread is running), and are added to in a safe way (all links must 889 // be updated in an MT-safe manner). 890 // 891 // Callers should be aware that an entry could be added just after 892 // _dictionary->bucket(index) is read here, so the caller will not see 893 // the new entry. 894 895 Klass* SystemDictionary::find(Symbol* class_name, 896 Handle class_loader, 897 Handle protection_domain, 898 TRAPS) { 899 900 // The result of this call should be consistent with the result 901 // of the call to resolve_instance_class_or_null(). 902 // See evaluation 6790209 and 4474172 for more details. 903 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 904 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 905 906 if (loader_data == NULL) { 907 // If the ClassLoaderData has not been setup, 908 // then the class loader has no entries in the dictionary. 909 return NULL; 910 } 911 912 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 913 int d_index = dictionary()->hash_to_index(d_hash); 914 915 { 916 // Note that we have an entry, and entries can be deleted only during GC, 917 // so we cannot allow GC to occur while we're holding this entry. 918 // We're using a No_Safepoint_Verifier to catch any place where we 919 // might potentially do a GC at all. 920 // Dictionary::do_unloading() asserts that classes in SD are only 921 // unloaded at a safepoint. Anonymous classes are not in SD. 922 No_Safepoint_Verifier nosafepoint; 923 return dictionary()->find(d_index, d_hash, class_name, loader_data, 924 protection_domain, THREAD); 925 } 926 } 927 928 929 // Look for a loaded instance or array klass by name. Do not do any loading. 930 // return NULL in case of error. 931 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 932 Handle class_loader, 933 Handle protection_domain, 934 TRAPS) { 935 Klass* k = NULL; 936 assert(class_name != NULL, "class name must be non NULL"); 937 938 if (FieldType::is_array(class_name)) { 939 // The name refers to an array. Parse the name. 940 // dimension and object_key in FieldArrayInfo are assigned as a 941 // side-effect of this call 942 FieldArrayInfo fd; 943 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 944 if (t != T_OBJECT) { 945 k = Universe::typeArrayKlassObj(t); 946 } else { 947 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 948 } 949 if (k != NULL) { 950 k = k->array_klass_or_null(fd.dimension()); 951 } 952 } else { 953 k = find(class_name, class_loader, protection_domain, THREAD); 954 } 955 return k; 956 } 957 958 // Note: this method is much like resolve_from_stream, but 959 // updates no supplemental data structures. 960 // TODO consolidate the two methods with a helper routine? 961 Klass* SystemDictionary::parse_stream(Symbol* class_name, 962 Handle class_loader, 963 Handle protection_domain, 964 ClassFileStream* st, 965 KlassHandle host_klass, 966 GrowableArray<Handle>* cp_patches, 967 TRAPS) { 968 TempNewSymbol parsed_name = NULL; 969 970 Ticks class_load_start_time = Ticks::now(); 971 972 ClassLoaderData* loader_data; 973 if (host_klass.not_null()) { 974 // Create a new CLD for anonymous class, that uses the same class loader 975 // as the host_klass 976 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 977 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 978 loader_data->record_dependency(host_klass(), CHECK_NULL); 979 } else { 980 loader_data = ClassLoaderData::class_loader_data(class_loader()); 981 } 982 983 // Parse the stream. Note that we do this even though this klass might 984 // already be present in the SystemDictionary, otherwise we would not 985 // throw potential ClassFormatErrors. 986 // 987 // Note: "name" is updated. 988 989 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 990 loader_data, 991 protection_domain, 992 host_klass, 993 cp_patches, 994 parsed_name, 995 true, 996 THREAD); 997 998 999 if (host_klass.not_null() && k.not_null()) { 1000 // If it's anonymous, initialize it now, since nobody else will. 1001 1002 { 1003 MutexLocker mu_r(Compile_lock, THREAD); 1004 1005 // Add to class hierarchy, initialize vtables, and do possible 1006 // deoptimizations. 1007 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1008 1009 // But, do not add to system dictionary. 1010 1011 // compiled code dependencies need to be validated anyway 1012 notice_modification(); 1013 } 1014 1015 // Rewrite and patch constant pool here. 1016 k->link_class(CHECK_NULL); 1017 if (cp_patches != NULL) { 1018 k->constants()->patch_resolved_references(cp_patches); 1019 } 1020 k->eager_initialize(CHECK_NULL); 1021 1022 // notify jvmti 1023 if (JvmtiExport::should_post_class_load()) { 1024 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1025 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1026 } 1027 1028 post_class_load_event(class_load_start_time, k, class_loader); 1029 } 1030 assert(host_klass.not_null() || cp_patches == NULL, 1031 "cp_patches only found with host_klass"); 1032 1033 return k(); 1034 } 1035 1036 // Add a klass to the system from a stream (called by jni_DefineClass and 1037 // JVM_DefineClass). 1038 // Note: class_name can be NULL. In that case we do not know the name of 1039 // the class until we have parsed the stream. 1040 1041 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1042 Handle class_loader, 1043 Handle protection_domain, 1044 ClassFileStream* st, 1045 bool verify, 1046 TRAPS) { 1047 1048 // Classloaders that support parallelism, e.g. bootstrap classloader, 1049 // or all classloaders with UnsyncloadClass do not acquire lock here 1050 bool DoObjectLock = true; 1051 if (is_parallelCapable(class_loader)) { 1052 DoObjectLock = false; 1053 } 1054 1055 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1056 1057 // Make sure we are synchronized on the class loader before we proceed 1058 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1059 check_loader_lock_contention(lockObject, THREAD); 1060 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1061 1062 TempNewSymbol parsed_name = NULL; 1063 1064 // Parse the stream. Note that we do this even though this klass might 1065 // already be present in the SystemDictionary, otherwise we would not 1066 // throw potential ClassFormatErrors. 1067 // 1068 // Note: "name" is updated. 1069 1070 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1071 loader_data, 1072 protection_domain, 1073 parsed_name, 1074 verify, 1075 THREAD); 1076 1077 const char* pkg = "java/"; 1078 if (!HAS_PENDING_EXCEPTION && 1079 !class_loader.is_null() && 1080 parsed_name != NULL && 1081 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1082 // It is illegal to define classes in the "java." package from 1083 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1084 ResourceMark rm(THREAD); 1085 char* name = parsed_name->as_C_string(); 1086 char* index = strrchr(name, '/'); 1087 *index = '\0'; // chop to just the package name 1088 while ((index = strchr(name, '/')) != NULL) { 1089 *index = '.'; // replace '/' with '.' in package name 1090 } 1091 const char* fmt = "Prohibited package name: %s"; 1092 size_t len = strlen(fmt) + strlen(name); 1093 char* message = NEW_RESOURCE_ARRAY(char, len); 1094 jio_snprintf(message, len, fmt, name); 1095 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1096 vmSymbols::java_lang_SecurityException(), message); 1097 } 1098 1099 if (!HAS_PENDING_EXCEPTION) { 1100 assert(parsed_name != NULL, "Sanity"); 1101 assert(class_name == NULL || class_name == parsed_name, "name mismatch"); 1102 // Verification prevents us from creating names with dots in them, this 1103 // asserts that that's the case. 1104 assert(is_internal_format(parsed_name), 1105 "external class name format used internally"); 1106 1107 // Add class just loaded 1108 // If a class loader supports parallel classloading handle parallel define requests 1109 // find_or_define_instance_class may return a different InstanceKlass 1110 if (is_parallelCapable(class_loader)) { 1111 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); 1112 } else { 1113 define_instance_class(k, THREAD); 1114 } 1115 } 1116 1117 // Make sure we have an entry in the SystemDictionary on success 1118 debug_only( { 1119 if (!HAS_PENDING_EXCEPTION) { 1120 assert(parsed_name != NULL, "parsed_name is still null?"); 1121 Symbol* h_name = k->name(); 1122 ClassLoaderData *defining_loader_data = k->class_loader_data(); 1123 1124 MutexLocker mu(SystemDictionary_lock, THREAD); 1125 1126 Klass* check = find_class(parsed_name, loader_data); 1127 assert(check == k(), "should be present in the dictionary"); 1128 1129 Klass* check2 = find_class(h_name, defining_loader_data); 1130 assert(check == check2, "name inconsistancy in SystemDictionary"); 1131 } 1132 } ); 1133 1134 return k(); 1135 } 1136 1137 1138 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1139 int number_of_entries) { 1140 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1141 "bad shared dictionary size."); 1142 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1143 } 1144 1145 1146 // If there is a shared dictionary, then find the entry for the 1147 // given shared system class, if any. 1148 1149 Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1150 if (shared_dictionary() != NULL) { 1151 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1152 int d_index = shared_dictionary()->hash_to_index(d_hash); 1153 1154 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1155 } else { 1156 return NULL; 1157 } 1158 } 1159 1160 1161 // Load a class from the shared spaces (found through the shared system 1162 // dictionary). Force the superclass and all interfaces to be loaded. 1163 // Update the class definition to include sibling classes and no 1164 // subclasses (yet). [Classes in the shared space are not part of the 1165 // object hierarchy until loaded.] 1166 1167 instanceKlassHandle SystemDictionary::load_shared_class( 1168 Symbol* class_name, Handle class_loader, TRAPS) { 1169 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1170 return load_shared_class(ik, class_loader, THREAD); 1171 } 1172 1173 instanceKlassHandle SystemDictionary::load_shared_class( 1174 instanceKlassHandle ik, Handle class_loader, TRAPS) { 1175 assert(class_loader.is_null(), "non-null classloader for shared class?"); 1176 if (ik.not_null()) { 1177 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1178 Symbol* class_name = ik->name(); 1179 1180 // Found the class, now load the superclass and interfaces. If they 1181 // are shared, add them to the main system dictionary and reset 1182 // their hierarchy references (supers, subs, and interfaces). 1183 1184 if (ik->super() != NULL) { 1185 Symbol* cn = ik->super()->name(); 1186 resolve_super_or_fail(class_name, cn, 1187 class_loader, Handle(), true, CHECK_(nh)); 1188 } 1189 1190 Array<Klass*>* interfaces = ik->local_interfaces(); 1191 int num_interfaces = interfaces->length(); 1192 for (int index = 0; index < num_interfaces; index++) { 1193 Klass* k = interfaces->at(index); 1194 1195 // Note: can not use InstanceKlass::cast here because 1196 // interfaces' InstanceKlass's C++ vtbls haven't been 1197 // reinitialized yet (they will be once the interface classes 1198 // are loaded) 1199 Symbol* name = k->name(); 1200 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); 1201 } 1202 1203 // Adjust methods to recover missing data. They need addresses for 1204 // interpreter entry points and their default native method address 1205 // must be reset. 1206 1207 // Updating methods must be done under a lock so multiple 1208 // threads don't update these in parallel 1209 // Shared classes are all currently loaded by the bootstrap 1210 // classloader, so this will never cause a deadlock on 1211 // a custom class loader lock. 1212 1213 { 1214 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1215 check_loader_lock_contention(lockObject, THREAD); 1216 ObjectLocker ol(lockObject, THREAD, true); 1217 ik->restore_unshareable_info(CHECK_(nh)); 1218 } 1219 1220 if (TraceClassLoading) { 1221 ResourceMark rm; 1222 tty->print("[Loaded %s", ik->external_name()); 1223 tty->print(" from shared objects file"); 1224 tty->print_cr("]"); 1225 } 1226 // notify a class loaded from shared object 1227 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()), 1228 true /* shared class */); 1229 } 1230 return ik; 1231 } 1232 1233 1234 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1235 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1236 if (class_loader.is_null()) { 1237 1238 // Search the shared system dictionary for classes preloaded into the 1239 // shared spaces. 1240 instanceKlassHandle k; 1241 { 1242 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1243 k = load_shared_class(class_name, class_loader, THREAD); 1244 } 1245 1246 if (k.is_null()) { 1247 // Use VM class loader 1248 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1249 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); 1250 } 1251 1252 // find_or_define_instance_class may return a different InstanceKlass 1253 if (!k.is_null()) { 1254 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1255 } 1256 return k; 1257 } else { 1258 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1259 ResourceMark rm(THREAD); 1260 1261 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1262 JavaThread* jt = (JavaThread*) THREAD; 1263 1264 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1265 ClassLoader::perf_app_classload_selftime(), 1266 ClassLoader::perf_app_classload_count(), 1267 jt->get_thread_stat()->perf_recursion_counts_addr(), 1268 jt->get_thread_stat()->perf_timers_addr(), 1269 PerfClassTraceTime::CLASS_LOAD); 1270 1271 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1272 // Translate to external class name format, i.e., convert '/' chars to '.' 1273 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1274 1275 JavaValue result(T_OBJECT); 1276 1277 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1278 1279 // Call public unsynchronized loadClass(String) directly for all class loaders 1280 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1281 // acquire a class-name based lock rather than the class loader object lock. 1282 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1283 // so the call to loadClassInternal() was not required. 1284 // 1285 // UnsyncloadClass flag means both call loadClass(String) and do 1286 // not acquire the class loader lock even for class loaders that are 1287 // not parallelCapable. This was a risky transitional 1288 // flag for diagnostic purposes only. It is risky to call 1289 // custom class loaders without synchronization. 1290 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1291 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1292 // Do NOT assume this will be supported in future releases. 1293 // 1294 // Added MustCallLoadClassInternal in case we discover in the field 1295 // a customer that counts on this call 1296 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1297 JavaCalls::call_special(&result, 1298 class_loader, 1299 spec_klass, 1300 vmSymbols::loadClassInternal_name(), 1301 vmSymbols::string_class_signature(), 1302 string, 1303 CHECK_(nh)); 1304 } else { 1305 JavaCalls::call_virtual(&result, 1306 class_loader, 1307 spec_klass, 1308 vmSymbols::loadClass_name(), 1309 vmSymbols::string_class_signature(), 1310 string, 1311 CHECK_(nh)); 1312 } 1313 1314 assert(result.get_type() == T_OBJECT, "just checking"); 1315 oop obj = (oop) result.get_jobject(); 1316 1317 // Primitive classes return null since forName() can not be 1318 // used to obtain any of the Class objects representing primitives or void 1319 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1320 instanceKlassHandle k = 1321 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1322 // For user defined Java class loaders, check that the name returned is 1323 // the same as that requested. This check is done for the bootstrap 1324 // loader when parsing the class file. 1325 if (class_name == k->name()) { 1326 return k; 1327 } 1328 } 1329 // Class is not found or has the wrong name, return NULL 1330 return nh; 1331 } 1332 } 1333 1334 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1335 1336 ClassLoaderData* loader_data = k->class_loader_data(); 1337 Handle class_loader_h(THREAD, loader_data->class_loader()); 1338 1339 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){} 1340 1341 // for bootstrap and other parallel classloaders don't acquire lock, 1342 // use placeholder token 1343 // If a parallelCapable class loader calls define_instance_class instead of 1344 // find_or_define_instance_class to get here, we have a timing 1345 // hole with systemDictionary updates and check_constraints 1346 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1347 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1348 compute_loader_lock_object(class_loader_h, THREAD)), 1349 "define called without lock"); 1350 } 1351 1352 // Check class-loading constraints. Throw exception if violation is detected. 1353 // Grabs and releases SystemDictionary_lock 1354 // The check_constraints/find_class call and update_dictionary sequence 1355 // must be "atomic" for a specific class/classloader pair so we never 1356 // define two different instanceKlasses for that class/classloader pair. 1357 // Existing classloaders will call define_instance_class with the 1358 // classloader lock held 1359 // Parallel classloaders will call find_or_define_instance_class 1360 // which will require a token to perform the define class 1361 Symbol* name_h = k->name(); 1362 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1363 int d_index = dictionary()->hash_to_index(d_hash); 1364 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1365 1366 // Register class just loaded with class loader (placed in Vector) 1367 // Note we do this before updating the dictionary, as this can 1368 // fail with an OutOfMemoryError (if it does, we will *not* put this 1369 // class in the dictionary and will not update the class hierarchy). 1370 // JVMTI FollowReferences needs to find the classes this way. 1371 if (k->class_loader() != NULL) { 1372 methodHandle m(THREAD, Universe::loader_addClass_method()); 1373 JavaValue result(T_VOID); 1374 JavaCallArguments args(class_loader_h); 1375 args.push_oop(Handle(THREAD, k->java_mirror())); 1376 JavaCalls::call(&result, m, &args, CHECK); 1377 } 1378 1379 // Add the new class. We need recompile lock during update of CHA. 1380 { 1381 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1382 int p_index = placeholders()->hash_to_index(p_hash); 1383 1384 MutexLocker mu_r(Compile_lock, THREAD); 1385 1386 // Add to class hierarchy, initialize vtables, and do possible 1387 // deoptimizations. 1388 add_to_hierarchy(k, CHECK); // No exception, but can block 1389 1390 // Add to systemDictionary - so other classes can see it. 1391 // Grabs and releases SystemDictionary_lock 1392 update_dictionary(d_index, d_hash, p_index, p_hash, 1393 k, class_loader_h, THREAD); 1394 } 1395 k->eager_initialize(THREAD); 1396 1397 // notify jvmti 1398 if (JvmtiExport::should_post_class_load()) { 1399 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1400 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1401 1402 } 1403 1404 } 1405 1406 // Support parallel classloading 1407 // All parallel class loaders, including bootstrap classloader 1408 // lock a placeholder entry for this class/class_loader pair 1409 // to allow parallel defines of different classes for this class loader 1410 // With AllowParallelDefine flag==true, in case they do not synchronize around 1411 // FindLoadedClass/DefineClass, calls, we check for parallel 1412 // loading for them, wait if a defineClass is in progress 1413 // and return the initial requestor's results 1414 // This flag does not apply to the bootstrap classloader. 1415 // With AllowParallelDefine flag==false, call through to define_instance_class 1416 // which will throw LinkageError: duplicate class definition. 1417 // False is the requested default. 1418 // For better performance, the class loaders should synchronize 1419 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1420 // potentially waste time reading and parsing the bytestream. 1421 // Note: VM callers should ensure consistency of k/class_name,class_loader 1422 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1423 1424 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1425 Symbol* name_h = k->name(); // passed in class_name may be null 1426 ClassLoaderData* loader_data = class_loader_data(class_loader); 1427 1428 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1429 int d_index = dictionary()->hash_to_index(d_hash); 1430 1431 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1432 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1433 int p_index = placeholders()->hash_to_index(p_hash); 1434 PlaceholderEntry* probe; 1435 1436 { 1437 MutexLocker mu(SystemDictionary_lock, THREAD); 1438 // First check if class already defined 1439 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1440 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1441 if (check != NULL) { 1442 return(instanceKlassHandle(THREAD, check)); 1443 } 1444 } 1445 1446 // Acquire define token for this class/classloader 1447 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1448 // Wait if another thread defining in parallel 1449 // All threads wait - even those that will throw duplicate class: otherwise 1450 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1451 // if other thread has not finished updating dictionary 1452 while (probe->definer() != NULL) { 1453 SystemDictionary_lock->wait(); 1454 } 1455 // Only special cases allow parallel defines and can use other thread's results 1456 // Other cases fall through, and may run into duplicate defines 1457 // caught by finding an entry in the SystemDictionary 1458 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1459 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1460 SystemDictionary_lock->notify_all(); 1461 #ifdef ASSERT 1462 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1463 assert(check != NULL, "definer missed recording success"); 1464 #endif 1465 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1466 } else { 1467 // This thread will define the class (even if earlier thread tried and had an error) 1468 probe->set_definer(THREAD); 1469 } 1470 } 1471 1472 define_instance_class(k, THREAD); 1473 1474 Handle linkage_exception = Handle(); // null handle 1475 1476 // definer must notify any waiting threads 1477 { 1478 MutexLocker mu(SystemDictionary_lock, THREAD); 1479 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1480 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1481 if (probe != NULL) { 1482 if (HAS_PENDING_EXCEPTION) { 1483 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1484 CLEAR_PENDING_EXCEPTION; 1485 } else { 1486 probe->set_instance_klass(k()); 1487 } 1488 probe->set_definer(NULL); 1489 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1490 SystemDictionary_lock->notify_all(); 1491 } 1492 } 1493 1494 // Can't throw exception while holding lock due to rank ordering 1495 if (linkage_exception() != NULL) { 1496 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1497 } 1498 1499 return k; 1500 } 1501 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1502 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1503 if (class_loader.is_null()) { 1504 return Handle(THREAD, _system_loader_lock_obj); 1505 } else { 1506 return class_loader; 1507 } 1508 } 1509 1510 // This method is added to check how often we have to wait to grab loader 1511 // lock. The results are being recorded in the performance counters defined in 1512 // ClassLoader::_sync_systemLoaderLockContentionRate and 1513 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1514 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1515 if (!UsePerfData) { 1516 return; 1517 } 1518 1519 assert(!loader_lock.is_null(), "NULL lock object"); 1520 1521 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1522 == ObjectSynchronizer::owner_other) { 1523 // contention will likely happen, so increment the corresponding 1524 // contention counter. 1525 if (loader_lock() == _system_loader_lock_obj) { 1526 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1527 } else { 1528 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1529 } 1530 } 1531 } 1532 1533 // ---------------------------------------------------------------------------- 1534 // Lookup 1535 1536 Klass* SystemDictionary::find_class(int index, unsigned int hash, 1537 Symbol* class_name, 1538 ClassLoaderData* loader_data) { 1539 assert_locked_or_safepoint(SystemDictionary_lock); 1540 assert (index == dictionary()->index_for(class_name, loader_data), 1541 "incorrect index?"); 1542 1543 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1544 return k; 1545 } 1546 1547 1548 // Basic find on classes in the midst of being loaded 1549 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1550 ClassLoaderData* loader_data) { 1551 assert_locked_or_safepoint(SystemDictionary_lock); 1552 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1553 int p_index = placeholders()->hash_to_index(p_hash); 1554 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1555 } 1556 1557 1558 // Used for assertions and verification only 1559 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1560 #ifndef ASSERT 1561 guarantee(VerifyBeforeGC || 1562 VerifyDuringGC || 1563 VerifyBeforeExit || 1564 VerifyDuringStartup || 1565 VerifyAfterGC, "too expensive"); 1566 #endif 1567 assert_locked_or_safepoint(SystemDictionary_lock); 1568 1569 // First look in the loaded class array 1570 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1571 int d_index = dictionary()->hash_to_index(d_hash); 1572 return find_class(d_index, d_hash, class_name, loader_data); 1573 } 1574 1575 1576 // Get the next class in the diictionary. 1577 Klass* SystemDictionary::try_get_next_class() { 1578 return dictionary()->try_get_next_class(); 1579 } 1580 1581 1582 // ---------------------------------------------------------------------------- 1583 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1584 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1585 // before a new class is used. 1586 1587 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1588 assert(k.not_null(), "just checking"); 1589 assert_locked_or_safepoint(Compile_lock); 1590 1591 // Link into hierachy. Make sure the vtables are initialized before linking into 1592 k->append_to_sibling_list(); // add to superklass/sibling list 1593 k->process_interfaces(THREAD); // handle all "implements" declarations 1594 k->set_init_state(InstanceKlass::loaded); 1595 // Now flush all code that depended on old class hierarchy. 1596 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1597 // Also, first reinitialize vtable because it may have gotten out of synch 1598 // while the new class wasn't connected to the class hierarchy. 1599 Universe::flush_dependents_on(k); 1600 } 1601 1602 1603 // ---------------------------------------------------------------------------- 1604 // GC support 1605 1606 // Following roots during mark-sweep is separated in two phases. 1607 // 1608 // The first phase follows preloaded classes and all other system 1609 // classes, since these will never get unloaded anyway. 1610 // 1611 // The second phase removes (unloads) unreachable classes from the 1612 // system dictionary and follows the remaining classes' contents. 1613 1614 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1615 roots_oops_do(blk, NULL); 1616 } 1617 1618 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1619 // Follow all system classes and temporary placeholders in dictionary 1620 dictionary()->always_strong_classes_do(closure); 1621 1622 // Placeholders. These represent classes we're actively loading. 1623 placeholders()->classes_do(closure); 1624 } 1625 1626 // Calculate a "good" systemdictionary size based 1627 // on predicted or current loaded classes count 1628 int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1629 int newsize = _old_default_sdsize; 1630 if ((classcount > 0) && !DumpSharedSpaces) { 1631 int desiredsize = classcount/_average_depth_goal; 1632 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1633 newsize = _primelist[++_sdgeneration]) { 1634 if (desiredsize <= newsize) { 1635 break; 1636 } 1637 } 1638 } 1639 return newsize; 1640 } 1641 1642 #ifdef ASSERT 1643 class VerifySDReachableAndLiveClosure : public OopClosure { 1644 private: 1645 BoolObjectClosure* _is_alive; 1646 1647 template <class T> void do_oop_work(T* p) { 1648 oop obj = oopDesc::load_decode_heap_oop(p); 1649 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); 1650 } 1651 1652 public: 1653 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1654 1655 virtual void do_oop(oop* p) { do_oop_work(p); } 1656 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1657 }; 1658 #endif 1659 1660 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1661 // Note: anonymous classes are not in the SD. 1662 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { 1663 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1664 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive); 1665 bool unloading_occurred = false; 1666 if (has_dead_loaders) { 1667 unloading_occurred = dictionary()->do_unloading(); 1668 constraints()->purge_loader_constraints(); 1669 resolution_errors()->purge_resolution_errors(); 1670 } 1671 // Oops referenced by the system dictionary may get unreachable independently 1672 // of the class loader (eg. cached protection domain oops). So we need to 1673 // explicitly unlink them here instead of in Dictionary::do_unloading. 1674 dictionary()->unlink(is_alive); 1675 #ifdef ASSERT 1676 VerifySDReachableAndLiveClosure cl(is_alive); 1677 dictionary()->oops_do(&cl); 1678 #endif 1679 return unloading_occurred; 1680 } 1681 1682 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1683 strong->do_oop(&_java_system_loader); 1684 strong->do_oop(&_system_loader_lock_obj); 1685 1686 // Adjust dictionary 1687 dictionary()->roots_oops_do(strong, weak); 1688 1689 // Visit extra methods 1690 invoke_method_table()->oops_do(strong); 1691 } 1692 1693 void SystemDictionary::oops_do(OopClosure* f) { 1694 f->do_oop(&_java_system_loader); 1695 f->do_oop(&_system_loader_lock_obj); 1696 1697 // Adjust dictionary 1698 dictionary()->oops_do(f); 1699 1700 // Visit extra methods 1701 invoke_method_table()->oops_do(f); 1702 } 1703 1704 // Extended Class redefinition support. 1705 // If one of these classes is replaced, we need to replace it in these places. 1706 // KlassClosure::do_klass should take the address of a class but we can 1707 // change that later. 1708 void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 1709 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 1710 f->do_klass(_well_known_klasses[k]); 1711 } 1712 1713 { 1714 for (int i = 0; i < T_VOID+1; i++) { 1715 if (_box_klasses[i] != NULL) { 1716 assert(i >= T_BOOLEAN, "checking"); 1717 f->do_klass(_box_klasses[i]); 1718 } 1719 } 1720 } 1721 1722 FilteredFieldsMap::classes_do(f); 1723 } 1724 1725 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 1726 f->do_klass(_abstract_ownable_synchronizer_klass); 1727 } 1728 1729 // Just the classes from defining class loaders 1730 // Don't iterate over placeholders 1731 void SystemDictionary::classes_do(void f(Klass*)) { 1732 dictionary()->classes_do(f); 1733 } 1734 1735 // Added for initialize_itable_for_klass 1736 // Just the classes from defining class loaders 1737 // Don't iterate over placeholders 1738 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 1739 dictionary()->classes_do(f, CHECK); 1740 } 1741 1742 // All classes, and their class loaders 1743 // Don't iterate over placeholders 1744 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 1745 dictionary()->classes_do(f); 1746 } 1747 1748 void SystemDictionary::placeholders_do(void f(Symbol*)) { 1749 placeholders()->entries_do(f); 1750 } 1751 1752 void SystemDictionary::methods_do(void f(Method*)) { 1753 dictionary()->methods_do(f); 1754 invoke_method_table()->methods_do(f); 1755 } 1756 1757 // ---------------------------------------------------------------------------- 1758 // Lazily load klasses 1759 1760 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1761 // if multiple threads calling this function, only one thread will load 1762 // the class. The other threads will find the loaded version once the 1763 // class is loaded. 1764 Klass* aos = _abstract_ownable_synchronizer_klass; 1765 if (aos == NULL) { 1766 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1767 // Force a fence to prevent any read before the write completes 1768 OrderAccess::fence(); 1769 _abstract_ownable_synchronizer_klass = k; 1770 } 1771 } 1772 1773 // ---------------------------------------------------------------------------- 1774 // Initialization 1775 1776 void SystemDictionary::initialize(TRAPS) { 1777 // Allocate arrays 1778 assert(dictionary() == NULL, 1779 "SystemDictionary should only be initialized once"); 1780 _sdgeneration = 0; 1781 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 1782 _placeholders = new PlaceholderTable(_nof_buckets); 1783 _number_of_modifications = 0; 1784 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1785 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1786 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1787 1788 // Allocate private object used as system class loader lock 1789 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1790 // Initialize basic classes 1791 initialize_preloaded_classes(CHECK); 1792 } 1793 1794 // Compact table of directions on the initialization of klasses: 1795 static const short wk_init_info[] = { 1796 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1797 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1798 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1799 | (int)SystemDictionary::option ), 1800 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1801 #undef WK_KLASS_INIT_INFO 1802 0 1803 }; 1804 1805 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 1806 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1807 int info = wk_init_info[id - FIRST_WKID]; 1808 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1809 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1810 Klass** klassp = &_well_known_klasses[id]; 1811 bool must_load = (init_opt < SystemDictionary::Opt); 1812 if ((*klassp) == NULL) { 1813 if (must_load) { 1814 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class 1815 } else { 1816 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass 1817 } 1818 } 1819 return ((*klassp) != NULL); 1820 } 1821 1822 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1823 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1824 for (int id = (int)start_id; id < (int)limit_id; id++) { 1825 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1826 int info = wk_init_info[id - FIRST_WKID]; 1827 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1828 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1829 1830 initialize_wk_klass((WKID)id, opt, CHECK); 1831 } 1832 1833 // move the starting value forward to the limit: 1834 start_id = limit_id; 1835 } 1836 1837 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1838 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 1839 // Preload commonly used klasses 1840 WKID scan = FIRST_WKID; 1841 // first do Object, then String, Class 1842 if (UseSharedSpaces) { 1843 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1844 // Initialize the constant pool for the Object_class 1845 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 1846 ik->constants()->restore_unshareable_info(CHECK); 1847 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1848 } else { 1849 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1850 } 1851 1852 // Calculate offsets for String and Class classes since they are loaded and 1853 // can be used after this point. 1854 java_lang_String::compute_offsets(); 1855 java_lang_Class::compute_offsets(); 1856 1857 // Fixup mirrors for classes loaded before java.lang.Class. 1858 // These calls iterate over the objects currently in the perm gen 1859 // so calling them at this point is matters (not before when there 1860 // are fewer objects and not later after there are more objects 1861 // in the perm gen. 1862 Universe::initialize_basic_type_mirrors(CHECK); 1863 Universe::fixup_mirrors(CHECK); 1864 1865 // do a bunch more: 1866 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 1867 1868 // Preload ref klasses and set reference types 1869 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 1870 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 1871 1872 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 1873 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 1874 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 1875 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 1876 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 1877 1878 // JSR 292 classes 1879 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 1880 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 1881 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 1882 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 1883 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); 1884 1885 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 1886 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 1887 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 1888 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 1889 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 1890 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 1891 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 1892 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 1893 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 1894 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 1895 1896 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 1897 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 1898 _has_loadClassInternal = (method != NULL); 1899 } 1900 { // Compute whether we should use checkPackageAccess or NOT 1901 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 1902 _has_checkPackageAccess = (method != NULL); 1903 } 1904 } 1905 1906 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 1907 // If so, returns the basic type it holds. If not, returns T_OBJECT. 1908 BasicType SystemDictionary::box_klass_type(Klass* k) { 1909 assert(k != NULL, ""); 1910 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 1911 if (_box_klasses[i] == k) 1912 return (BasicType)i; 1913 } 1914 return T_OBJECT; 1915 } 1916 1917 // Constraints on class loaders. The details of the algorithm can be 1918 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 1919 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 1920 // that the system dictionary needs to maintain a set of contraints that 1921 // must be satisfied by all classes in the dictionary. 1922 // if defining is true, then LinkageError if already in systemDictionary 1923 // if initiating loader, then ok if InstanceKlass matches existing entry 1924 1925 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 1926 instanceKlassHandle k, 1927 Handle class_loader, bool defining, 1928 TRAPS) { 1929 const char *linkage_error = NULL; 1930 { 1931 Symbol* name = k->name(); 1932 ClassLoaderData *loader_data = class_loader_data(class_loader); 1933 1934 MutexLocker mu(SystemDictionary_lock, THREAD); 1935 1936 Klass* check = find_class(d_index, d_hash, name, loader_data); 1937 if (check != (Klass*)NULL) { 1938 // if different InstanceKlass - duplicate class definition, 1939 // else - ok, class loaded by a different thread in parallel, 1940 // we should only have found it if it was done loading and ok to use 1941 // system dictionary only holds instance classes, placeholders 1942 // also holds array classes 1943 1944 assert(check->oop_is_instance(), "noninstance in systemdictionary"); 1945 if ((defining == true) || (k() != check)) { 1946 linkage_error = "loader (instance of %s): attempted duplicate class " 1947 "definition for name: \"%s\""; 1948 } else { 1949 return; 1950 } 1951 } 1952 1953 #ifdef ASSERT 1954 Symbol* ph_check = find_placeholder(name, loader_data); 1955 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 1956 #endif 1957 1958 if (linkage_error == NULL) { 1959 if (constraints()->check_or_update(k, class_loader, name) == false) { 1960 linkage_error = "loader constraint violation: loader (instance of %s)" 1961 " previously initiated loading for a different type with name \"%s\""; 1962 } 1963 } 1964 } 1965 1966 // Throw error now if needed (cannot throw while holding 1967 // SystemDictionary_lock because of rank ordering) 1968 1969 if (linkage_error) { 1970 ResourceMark rm(THREAD); 1971 const char* class_loader_name = loader_name(class_loader()); 1972 char* type_name = k->name()->as_C_string(); 1973 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + 1974 strlen(type_name); 1975 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 1976 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); 1977 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 1978 } 1979 } 1980 1981 1982 // Update system dictionary - done after check_constraint and add_to_hierachy 1983 // have been called. 1984 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 1985 int p_index, unsigned int p_hash, 1986 instanceKlassHandle k, 1987 Handle class_loader, 1988 TRAPS) { 1989 // Compile_lock prevents systemDictionary updates during compilations 1990 assert_locked_or_safepoint(Compile_lock); 1991 Symbol* name = k->name(); 1992 ClassLoaderData *loader_data = class_loader_data(class_loader); 1993 1994 { 1995 MutexLocker mu1(SystemDictionary_lock, THREAD); 1996 1997 // See whether biased locking is enabled and if so set it for this 1998 // klass. 1999 // Note that this must be done past the last potential blocking 2000 // point / safepoint. We enable biased locking lazily using a 2001 // VM_Operation to iterate the SystemDictionary and installing the 2002 // biasable mark word into each InstanceKlass's prototype header. 2003 // To avoid race conditions where we accidentally miss enabling the 2004 // optimization for one class in the process of being added to the 2005 // dictionary, we must not safepoint after the test of 2006 // BiasedLocking::enabled(). 2007 if (UseBiasedLocking && BiasedLocking::enabled()) { 2008 // Set biased locking bit for all loaded classes; it will be 2009 // cleared if revocation occurs too often for this type 2010 // NOTE that we must only do this when the class is initally 2011 // defined, not each time it is referenced from a new class loader 2012 if (k->class_loader() == class_loader()) { 2013 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2014 } 2015 } 2016 2017 // Make a new system dictionary entry. 2018 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2019 if (sd_check == NULL) { 2020 dictionary()->add_klass(name, loader_data, k); 2021 notice_modification(); 2022 } 2023 #ifdef ASSERT 2024 sd_check = find_class(d_index, d_hash, name, loader_data); 2025 assert (sd_check != NULL, "should have entry in system dictionary"); 2026 // Note: there may be a placeholder entry: for circularity testing 2027 // or for parallel defines 2028 #endif 2029 SystemDictionary_lock->notify_all(); 2030 } 2031 } 2032 2033 2034 // Try to find a class name using the loader constraints. The 2035 // loader constraints might know about a class that isn't fully loaded 2036 // yet and these will be ignored. 2037 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2038 Symbol* class_name, Handle class_loader, TRAPS) { 2039 2040 // First see if it has been loaded directly. 2041 // Force the protection domain to be null. (This removes protection checks.) 2042 Handle no_protection_domain; 2043 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2044 no_protection_domain, CHECK_NULL); 2045 if (klass != NULL) 2046 return klass; 2047 2048 // Now look to see if it has been loaded elsewhere, and is subject to 2049 // a loader constraint that would require this loader to return the 2050 // klass that is already loaded. 2051 if (FieldType::is_array(class_name)) { 2052 // For array classes, their Klass*s are not kept in the 2053 // constraint table. The element Klass*s are. 2054 FieldArrayInfo fd; 2055 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2056 if (t != T_OBJECT) { 2057 klass = Universe::typeArrayKlassObj(t); 2058 } else { 2059 MutexLocker mu(SystemDictionary_lock, THREAD); 2060 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2061 } 2062 // If element class already loaded, allocate array klass 2063 if (klass != NULL) { 2064 klass = klass->array_klass_or_null(fd.dimension()); 2065 } 2066 } else { 2067 MutexLocker mu(SystemDictionary_lock, THREAD); 2068 // Non-array classes are easy: simply check the constraint table. 2069 klass = constraints()->find_constrained_klass(class_name, class_loader); 2070 } 2071 2072 return klass; 2073 } 2074 2075 2076 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2077 Handle class_loader1, 2078 Handle class_loader2, 2079 Thread* THREAD) { 2080 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2081 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2082 2083 Symbol* constraint_name = NULL; 2084 if (!FieldType::is_array(class_name)) { 2085 constraint_name = class_name; 2086 } else { 2087 // For array classes, their Klass*s are not kept in the 2088 // constraint table. The element classes are. 2089 FieldArrayInfo fd; 2090 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2091 // primitive types always pass 2092 if (t != T_OBJECT) { 2093 return true; 2094 } else { 2095 constraint_name = fd.object_key(); 2096 } 2097 } 2098 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2099 int d_index1 = dictionary()->hash_to_index(d_hash1); 2100 2101 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2102 int d_index2 = dictionary()->hash_to_index(d_hash2); 2103 { 2104 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2105 2106 // Better never do a GC while we're holding these oops 2107 No_Safepoint_Verifier nosafepoint; 2108 2109 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2110 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2111 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2112 klass2, class_loader2); 2113 } 2114 } 2115 2116 // Add entry to resolution error table to record the error when the first 2117 // attempt to resolve a reference to a class has failed. 2118 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, 2119 Symbol* error, Symbol* message) { 2120 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2121 int index = resolution_errors()->hash_to_index(hash); 2122 { 2123 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2124 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2125 } 2126 } 2127 2128 // Delete a resolution error for RedefineClasses for a constant pool is going away 2129 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2130 resolution_errors()->delete_entry(pool); 2131 } 2132 2133 // Lookup resolution error table. Returns error if found, otherwise NULL. 2134 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which, 2135 Symbol** message) { 2136 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2137 int index = resolution_errors()->hash_to_index(hash); 2138 { 2139 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2140 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2141 if (entry != NULL) { 2142 *message = entry->message(); 2143 return entry->error(); 2144 } else { 2145 return NULL; 2146 } 2147 } 2148 } 2149 2150 2151 // Signature constraints ensure that callers and callees agree about 2152 // the meaning of type names in their signatures. This routine is the 2153 // intake for constraints. It collects them from several places: 2154 // 2155 // * LinkResolver::resolve_method (if check_access is true) requires 2156 // that the resolving class (the caller) and the defining class of 2157 // the resolved method (the callee) agree on each type in the 2158 // method's signature. 2159 // 2160 // * LinkResolver::resolve_interface_method performs exactly the same 2161 // checks. 2162 // 2163 // * LinkResolver::resolve_field requires that the constant pool 2164 // attempting to link to a field agree with the field's defining 2165 // class about the type of the field signature. 2166 // 2167 // * klassVtable::initialize_vtable requires that, when a class 2168 // overrides a vtable entry allocated by a superclass, that the 2169 // overriding method (i.e., the callee) agree with the superclass 2170 // on each type in the method's signature. 2171 // 2172 // * klassItable::initialize_itable requires that, when a class fills 2173 // in its itables, for each non-abstract method installed in an 2174 // itable, the method (i.e., the callee) agree with the interface 2175 // on each type in the method's signature. 2176 // 2177 // All those methods have a boolean (check_access, checkconstraints) 2178 // which turns off the checks. This is used from specialized contexts 2179 // such as bootstrapping, dumping, and debugging. 2180 // 2181 // No direct constraint is placed between the class and its 2182 // supertypes. Constraints are only placed along linked relations 2183 // between callers and callees. When a method overrides or implements 2184 // an abstract method in a supertype (superclass or interface), the 2185 // constraints are placed as if the supertype were the caller to the 2186 // overriding method. (This works well, since callers to the 2187 // supertype have already established agreement between themselves and 2188 // the supertype.) As a result of all this, a class can disagree with 2189 // its supertype about the meaning of a type name, as long as that 2190 // class neither calls a relevant method of the supertype, nor is 2191 // called (perhaps via an override) from the supertype. 2192 // 2193 // 2194 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2195 // 2196 // Make sure all class components (including arrays) in the given 2197 // signature will be resolved to the same class in both loaders. 2198 // Returns the name of the type that failed a loader constraint check, or 2199 // NULL if no constraint failed. No exception except OOME is thrown. 2200 // Arrays are not added to the loader constraint table, their elements are. 2201 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2202 Handle loader1, Handle loader2, 2203 bool is_method, TRAPS) { 2204 // Nothing to do if loaders are the same. 2205 if (loader1() == loader2()) { 2206 return NULL; 2207 } 2208 2209 SignatureStream sig_strm(signature, is_method); 2210 while (!sig_strm.is_done()) { 2211 if (sig_strm.is_object()) { 2212 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2213 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2214 return sig; 2215 } 2216 } 2217 sig_strm.next(); 2218 } 2219 return NULL; 2220 } 2221 2222 2223 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2224 Symbol* signature, 2225 TRAPS) { 2226 methodHandle empty; 2227 assert(MethodHandles::is_signature_polymorphic(iid) && 2228 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2229 iid != vmIntrinsics::_invokeGeneric, 2230 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid))); 2231 2232 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2233 int index = invoke_method_table()->hash_to_index(hash); 2234 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2235 methodHandle m; 2236 if (spe == NULL || spe->method() == NULL) { 2237 spe = NULL; 2238 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2239 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2240 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier, 2241 methodHandle(), CompileThreshold, "MH", CHECK_(empty)); 2242 2243 // Now grab the lock. We might have to throw away the new method, 2244 // if a racing thread has managed to install one at the same time. 2245 { 2246 MutexLocker ml(SystemDictionary_lock, THREAD); 2247 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2248 if (spe == NULL) 2249 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2250 if (spe->method() == NULL) 2251 spe->set_method(m()); 2252 } 2253 } 2254 2255 assert(spe != NULL && spe->method() != NULL, ""); 2256 return spe->method(); 2257 } 2258 2259 // Helper for unpacking the return value from linkMethod and linkCallSite. 2260 static methodHandle unpack_method_and_appendix(Handle mname, 2261 KlassHandle accessing_klass, 2262 objArrayHandle appendix_box, 2263 Handle* appendix_result, 2264 TRAPS) { 2265 methodHandle empty; 2266 if (mname.not_null()) { 2267 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2268 if (vmtarget != NULL && vmtarget->is_method()) { 2269 Method* m = (Method*)vmtarget; 2270 oop appendix = appendix_box->obj_at(0); 2271 if (TraceMethodHandles) { 2272 #ifndef PRODUCT 2273 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2274 m->print(); 2275 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2276 tty->cr(); 2277 #endif //PRODUCT 2278 } 2279 (*appendix_result) = Handle(THREAD, appendix); 2280 // the target is stored in the cpCache and if a reference to this 2281 // MethodName is dropped we need a way to make sure the 2282 // class_loader containing this method is kept alive. 2283 // FIXME: the appendix might also preserve this dependency. 2284 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2285 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2286 return methodHandle(THREAD, m); 2287 } 2288 } 2289 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2290 return empty; 2291 } 2292 2293 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name, 2294 Symbol* signature, 2295 KlassHandle accessing_klass, 2296 Handle *appendix_result, 2297 Handle *method_type_result, 2298 TRAPS) { 2299 methodHandle empty; 2300 assert(!THREAD->is_Compiler_thread(), ""); 2301 Handle method_type = 2302 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2303 if (false) { // FIXME: Decide if the Java upcall should resolve signatures. 2304 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2305 } 2306 2307 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass(); 2308 int ref_kind = JVM_REF_invokeVirtual; 2309 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2310 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2311 assert(appendix_box->obj_at(0) == NULL, ""); 2312 2313 // This should not happen. JDK code should take care of that. 2314 if (accessing_klass.is_null() || method_type.is_null()) { 2315 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2316 } 2317 2318 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2319 JavaCallArguments args; 2320 args.push_oop(accessing_klass()->java_mirror()); 2321 args.push_int(ref_kind); 2322 args.push_oop(mh_klass()->java_mirror()); 2323 args.push_oop(name_str()); 2324 args.push_oop(method_type()); 2325 args.push_oop(appendix_box()); 2326 JavaValue result(T_OBJECT); 2327 JavaCalls::call_static(&result, 2328 SystemDictionary::MethodHandleNatives_klass(), 2329 vmSymbols::linkMethod_name(), 2330 vmSymbols::linkMethod_signature(), 2331 &args, CHECK_(empty)); 2332 Handle mname(THREAD, (oop) result.get_jobject()); 2333 (*method_type_result) = method_type; 2334 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2335 } 2336 2337 2338 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2339 // signature, as interpreted relative to the given class loader. 2340 // Because of class loader constraints, all method handle usage must be 2341 // consistent with this loader. 2342 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2343 KlassHandle accessing_klass, 2344 TRAPS) { 2345 Handle empty; 2346 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2347 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2348 int index = invoke_method_table()->hash_to_index(hash); 2349 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2350 if (spe != NULL && spe->method_type() != NULL) { 2351 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2352 return Handle(THREAD, spe->method_type()); 2353 } else if (THREAD->is_Compiler_thread()) { 2354 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2355 return Handle(); // do not attempt from within compiler, unless it was cached 2356 } 2357 2358 Handle class_loader, protection_domain; 2359 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader 2360 int npts = ArgumentCount(signature).size(); 2361 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2362 int arg = 0; 2363 Handle rt; // the return type from the signature 2364 ResourceMark rm(THREAD); 2365 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2366 oop mirror = NULL; 2367 if (is_on_bcp) { 2368 // Note: class_loader & protection_domain are both null at this point. 2369 mirror = ss.as_java_mirror(class_loader, protection_domain, 2370 SignatureStream::ReturnNull, CHECK_(empty)); 2371 if (mirror == NULL) { 2372 // fall back from BCP to accessing_klass 2373 if (accessing_klass.not_null()) { 2374 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2375 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2376 } 2377 is_on_bcp = false; 2378 } 2379 } 2380 if (!is_on_bcp) { 2381 // Resolve, throwing a real error if it doesn't work. 2382 mirror = ss.as_java_mirror(class_loader, protection_domain, 2383 SignatureStream::NCDFError, CHECK_(empty)); 2384 } 2385 if (ss.at_return_type()) 2386 rt = Handle(THREAD, mirror); 2387 else 2388 pts->obj_at_put(arg++, mirror); 2389 2390 // Check accessibility. 2391 if (ss.is_object() && accessing_klass.not_null()) { 2392 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2393 mirror = NULL; // safety 2394 // Emulate ConstantPool::verify_constant_pool_resolve. 2395 if (sel_klass->oop_is_objArray()) 2396 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2397 if (sel_klass->oop_is_instance()) { 2398 KlassHandle sel_kh(THREAD, sel_klass); 2399 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2400 } 2401 } 2402 } 2403 assert(arg == npts, ""); 2404 2405 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType 2406 JavaCallArguments args(Handle(THREAD, rt())); 2407 args.push_oop(pts()); 2408 JavaValue result(T_OBJECT); 2409 JavaCalls::call_static(&result, 2410 SystemDictionary::MethodHandleNatives_klass(), 2411 vmSymbols::findMethodHandleType_name(), 2412 vmSymbols::findMethodHandleType_signature(), 2413 &args, CHECK_(empty)); 2414 Handle method_type(THREAD, (oop) result.get_jobject()); 2415 2416 if (is_on_bcp) { 2417 // We can cache this MethodType inside the JVM. 2418 MutexLocker ml(SystemDictionary_lock, THREAD); 2419 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2420 if (spe == NULL) 2421 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2422 if (spe->method_type() == NULL) { 2423 spe->set_method_type(method_type()); 2424 } 2425 } 2426 2427 // report back to the caller with the MethodType 2428 return method_type; 2429 } 2430 2431 // Ask Java code to find or construct a method handle constant. 2432 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2433 int ref_kind, //e.g., JVM_REF_invokeVirtual 2434 KlassHandle callee, 2435 Symbol* name_sym, 2436 Symbol* signature, 2437 TRAPS) { 2438 Handle empty; 2439 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2440 Handle type; 2441 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2442 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2443 } else if (caller.is_null()) { 2444 // This should not happen. JDK code should take care of that. 2445 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2446 } else { 2447 ResourceMark rm(THREAD); 2448 SignatureStream ss(signature, false); 2449 if (!ss.is_done()) { 2450 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2451 SignatureStream::NCDFError, CHECK_(empty)); 2452 type = Handle(THREAD, mirror); 2453 ss.next(); 2454 if (!ss.is_done()) type = Handle(); // error! 2455 } 2456 } 2457 if (type.is_null()) { 2458 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2459 } 2460 2461 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2462 JavaCallArguments args; 2463 args.push_oop(caller->java_mirror()); // the referring class 2464 args.push_int(ref_kind); 2465 args.push_oop(callee->java_mirror()); // the target class 2466 args.push_oop(name()); 2467 args.push_oop(type()); 2468 JavaValue result(T_OBJECT); 2469 JavaCalls::call_static(&result, 2470 SystemDictionary::MethodHandleNatives_klass(), 2471 vmSymbols::linkMethodHandleConstant_name(), 2472 vmSymbols::linkMethodHandleConstant_signature(), 2473 &args, CHECK_(empty)); 2474 return Handle(THREAD, (oop) result.get_jobject()); 2475 } 2476 2477 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2478 // name and signature, as interpreted relative to the given class loader. 2479 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2480 Handle bootstrap_specifier, 2481 Symbol* name, 2482 Symbol* type, 2483 Handle *appendix_result, 2484 Handle *method_type_result, 2485 TRAPS) { 2486 methodHandle empty; 2487 Handle bsm, info; 2488 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2489 bsm = bootstrap_specifier; 2490 } else { 2491 assert(bootstrap_specifier->is_objArray(), ""); 2492 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2493 int len = args->length(); 2494 assert(len >= 1, ""); 2495 bsm = Handle(THREAD, args->obj_at(0)); 2496 if (len > 1) { 2497 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2498 for (int i = 1; i < len; i++) 2499 args1->obj_at_put(i-1, args->obj_at(i)); 2500 info = Handle(THREAD, args1); 2501 } 2502 } 2503 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2504 "caller must supply a valid BSM"); 2505 2506 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2507 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2508 2509 // This should not happen. JDK code should take care of that. 2510 if (caller.is_null() || method_type.is_null()) { 2511 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2512 } 2513 2514 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2515 assert(appendix_box->obj_at(0) == NULL, ""); 2516 2517 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2518 JavaCallArguments args; 2519 args.push_oop(caller->java_mirror()); 2520 args.push_oop(bsm()); 2521 args.push_oop(method_name()); 2522 args.push_oop(method_type()); 2523 args.push_oop(info()); 2524 args.push_oop(appendix_box); 2525 JavaValue result(T_OBJECT); 2526 JavaCalls::call_static(&result, 2527 SystemDictionary::MethodHandleNatives_klass(), 2528 vmSymbols::linkCallSite_name(), 2529 vmSymbols::linkCallSite_signature(), 2530 &args, CHECK_(empty)); 2531 Handle mname(THREAD, (oop) result.get_jobject()); 2532 (*method_type_result) = method_type; 2533 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2534 } 2535 2536 // Since the identity hash code for symbols changes when the symbols are 2537 // moved from the regular perm gen (hash in the mark word) to the shared 2538 // spaces (hash is the address), the classes loaded into the dictionary 2539 // may be in the wrong buckets. 2540 2541 void SystemDictionary::reorder_dictionary() { 2542 dictionary()->reorder_dictionary(); 2543 } 2544 2545 2546 void SystemDictionary::copy_buckets(char** top, char* end) { 2547 dictionary()->copy_buckets(top, end); 2548 } 2549 2550 2551 void SystemDictionary::copy_table(char** top, char* end) { 2552 dictionary()->copy_table(top, end); 2553 } 2554 2555 2556 void SystemDictionary::reverse() { 2557 dictionary()->reverse(); 2558 } 2559 2560 int SystemDictionary::number_of_classes() { 2561 return dictionary()->number_of_entries(); 2562 } 2563 2564 2565 // ---------------------------------------------------------------------------- 2566 #ifndef PRODUCT 2567 2568 void SystemDictionary::print() { 2569 dictionary()->print(); 2570 2571 // Placeholders 2572 GCMutexLocker mu(SystemDictionary_lock); 2573 placeholders()->print(); 2574 2575 // loader constraints - print under SD_lock 2576 constraints()->print(); 2577 } 2578 2579 #endif 2580 2581 void SystemDictionary::verify() { 2582 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2583 guarantee(constraints() != NULL, 2584 "Verify of loader constraints failed"); 2585 guarantee(dictionary()->number_of_entries() >= 0 && 2586 placeholders()->number_of_entries() >= 0, 2587 "Verify of system dictionary failed"); 2588 2589 // Verify dictionary 2590 dictionary()->verify(); 2591 2592 GCMutexLocker mu(SystemDictionary_lock); 2593 placeholders()->verify(); 2594 2595 // Verify constraint table 2596 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2597 constraints()->verify(dictionary(), placeholders()); 2598 } 2599 2600 // utility function for class load event 2601 void SystemDictionary::post_class_load_event(const Ticks& start_time, 2602 instanceKlassHandle k, 2603 Handle initiating_loader) { 2604 #if INCLUDE_TRACE 2605 EventClassLoad event(UNTIMED); 2606 if (event.should_commit()) { 2607 event.set_starttime(start_time); 2608 event.set_loadedClass(k()); 2609 oop defining_class_loader = k->class_loader(); 2610 event.set_definingClassLoader(defining_class_loader != NULL ? 2611 defining_class_loader->klass() : (Klass*)NULL); 2612 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader(); 2613 event.set_initiatingClassLoader(class_loader != NULL ? 2614 class_loader->klass() : (Klass*)NULL); 2615 event.commit(); 2616 } 2617 #endif /* INCLUDE_TRACE */ 2618 } 2619 2620 #ifndef PRODUCT 2621 2622 // statistics code 2623 class ClassStatistics: AllStatic { 2624 private: 2625 static int nclasses; // number of classes 2626 static int nmethods; // number of methods 2627 static int nmethoddata; // number of methodData 2628 static int class_size; // size of class objects in words 2629 static int method_size; // size of method objects in words 2630 static int debug_size; // size of debug info in methods 2631 static int methoddata_size; // size of methodData objects in words 2632 2633 static void do_class(Klass* k) { 2634 nclasses++; 2635 class_size += k->size(); 2636 if (k->oop_is_instance()) { 2637 InstanceKlass* ik = (InstanceKlass*)k; 2638 class_size += ik->methods()->size(); 2639 class_size += ik->constants()->size(); 2640 class_size += ik->local_interfaces()->size(); 2641 class_size += ik->transitive_interfaces()->size(); 2642 // We do not have to count implementors, since we only store one! 2643 // SSS: How should these be accounted now that they have moved? 2644 // class_size += ik->fields()->length(); 2645 } 2646 } 2647 2648 static void do_method(Method* m) { 2649 nmethods++; 2650 method_size += m->size(); 2651 // class loader uses same objArray for empty vectors, so don't count these 2652 if (m->has_stackmap_table()) { 2653 method_size += m->stackmap_data()->size(); 2654 } 2655 2656 MethodData* mdo = m->method_data(); 2657 if (mdo != NULL) { 2658 nmethoddata++; 2659 methoddata_size += mdo->size(); 2660 } 2661 } 2662 2663 public: 2664 static void print() { 2665 SystemDictionary::classes_do(do_class); 2666 SystemDictionary::methods_do(do_method); 2667 tty->print_cr("Class statistics:"); 2668 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); 2669 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, 2670 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); 2671 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); 2672 } 2673 }; 2674 2675 2676 int ClassStatistics::nclasses = 0; 2677 int ClassStatistics::nmethods = 0; 2678 int ClassStatistics::nmethoddata = 0; 2679 int ClassStatistics::class_size = 0; 2680 int ClassStatistics::method_size = 0; 2681 int ClassStatistics::debug_size = 0; 2682 int ClassStatistics::methoddata_size = 0; 2683 2684 void SystemDictionary::print_class_statistics() { 2685 ResourceMark rm; 2686 ClassStatistics::print(); 2687 } 2688 2689 2690 class MethodStatistics: AllStatic { 2691 public: 2692 enum { 2693 max_parameter_size = 10 2694 }; 2695 private: 2696 2697 static int _number_of_methods; 2698 static int _number_of_final_methods; 2699 static int _number_of_static_methods; 2700 static int _number_of_native_methods; 2701 static int _number_of_synchronized_methods; 2702 static int _number_of_profiled_methods; 2703 static int _number_of_bytecodes; 2704 static int _parameter_size_profile[max_parameter_size]; 2705 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; 2706 2707 static void initialize() { 2708 _number_of_methods = 0; 2709 _number_of_final_methods = 0; 2710 _number_of_static_methods = 0; 2711 _number_of_native_methods = 0; 2712 _number_of_synchronized_methods = 0; 2713 _number_of_profiled_methods = 0; 2714 _number_of_bytecodes = 0; 2715 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; 2716 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; 2717 }; 2718 2719 static void do_method(Method* m) { 2720 _number_of_methods++; 2721 // collect flag info 2722 if (m->is_final() ) _number_of_final_methods++; 2723 if (m->is_static() ) _number_of_static_methods++; 2724 if (m->is_native() ) _number_of_native_methods++; 2725 if (m->is_synchronized()) _number_of_synchronized_methods++; 2726 if (m->method_data() != NULL) _number_of_profiled_methods++; 2727 // collect parameter size info (add one for receiver, if any) 2728 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; 2729 // collect bytecodes info 2730 { 2731 Thread *thread = Thread::current(); 2732 HandleMark hm(thread); 2733 BytecodeStream s(methodHandle(thread, m)); 2734 Bytecodes::Code c; 2735 while ((c = s.next()) >= 0) { 2736 _number_of_bytecodes++; 2737 _bytecodes_profile[c]++; 2738 } 2739 } 2740 } 2741 2742 public: 2743 static void print() { 2744 initialize(); 2745 SystemDictionary::methods_do(do_method); 2746 // generate output 2747 tty->cr(); 2748 tty->print_cr("Method statistics (static):"); 2749 // flag distribution 2750 tty->cr(); 2751 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); 2752 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); 2753 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); 2754 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); 2755 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); 2756 // parameter size profile 2757 tty->cr(); 2758 { int tot = 0; 2759 int avg = 0; 2760 for (int i = 0; i < max_parameter_size; i++) { 2761 int n = _parameter_size_profile[i]; 2762 tot += n; 2763 avg += n*i; 2764 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); 2765 } 2766 assert(tot == _number_of_methods, "should be the same"); 2767 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); 2768 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); 2769 } 2770 // bytecodes profile 2771 tty->cr(); 2772 { int tot = 0; 2773 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { 2774 if (Bytecodes::is_defined(i)) { 2775 Bytecodes::Code c = Bytecodes::cast(i); 2776 int n = _bytecodes_profile[c]; 2777 tot += n; 2778 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); 2779 } 2780 } 2781 assert(tot == _number_of_bytecodes, "should be the same"); 2782 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); 2783 } 2784 tty->cr(); 2785 } 2786 }; 2787 2788 int MethodStatistics::_number_of_methods; 2789 int MethodStatistics::_number_of_final_methods; 2790 int MethodStatistics::_number_of_static_methods; 2791 int MethodStatistics::_number_of_native_methods; 2792 int MethodStatistics::_number_of_synchronized_methods; 2793 int MethodStatistics::_number_of_profiled_methods; 2794 int MethodStatistics::_number_of_bytecodes; 2795 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; 2796 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; 2797 2798 2799 void SystemDictionary::print_method_statistics() { 2800 MethodStatistics::print(); 2801 } 2802 2803 #endif // PRODUCT