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 "interpreter/linkResolver.hpp" 39 #include "memory/gcLocker.hpp" 40 #include "memory/oopFactory.hpp" 41 #include "oops/instanceKlass.hpp" 42 #include "oops/instanceRefKlass.hpp" 43 #include "oops/klass.inline.hpp" 44 #include "oops/methodData.hpp" 45 #include "oops/objArrayKlass.hpp" 46 #include "oops/oop.inline.hpp" 47 #include "oops/oop.inline2.hpp" 48 #include "oops/typeArrayKlass.hpp" 49 #include "prims/jvmtiEnvBase.hpp" 50 #include "prims/methodHandles.hpp" 51 #include "runtime/biasedLocking.hpp" 52 #include "runtime/fieldType.hpp" 53 #include "runtime/handles.inline.hpp" 54 #include "runtime/java.hpp" 55 #include "runtime/javaCalls.hpp" 56 #include "runtime/mutexLocker.hpp" 57 #include "runtime/orderAccess.inline.hpp" 58 #include "runtime/signature.hpp" 59 #include "services/classLoadingService.hpp" 60 #include "services/threadService.hpp" 61 #include "utilities/macros.hpp" 62 #include "utilities/ticks.hpp" 63 64 #if INCLUDE_TRACE 65 #include "trace/tracing.hpp" 66 #endif 67 68 Dictionary* SystemDictionary::_dictionary = NULL; 69 PlaceholderTable* SystemDictionary::_placeholders = NULL; 70 Dictionary* SystemDictionary::_shared_dictionary = NULL; 71 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 72 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 73 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 74 75 76 int SystemDictionary::_number_of_modifications = 0; 77 int SystemDictionary::_sdgeneration = 0; 78 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 79 20201,40423,99991}; 80 81 oop SystemDictionary::_system_loader_lock_obj = NULL; 82 83 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 84 = { NULL /*, NULL...*/ }; 85 86 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 87 88 oop SystemDictionary::_java_system_loader = NULL; 89 90 bool SystemDictionary::_has_loadClassInternal = false; 91 bool SystemDictionary::_has_checkPackageAccess = false; 92 93 // lazily initialized klass variables 94 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 95 96 97 // ---------------------------------------------------------------------------- 98 // Java-level SystemLoader 99 100 oop SystemDictionary::java_system_loader() { 101 return _java_system_loader; 102 } 103 104 void SystemDictionary::compute_java_system_loader(TRAPS) { 105 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 106 JavaValue result(T_OBJECT); 107 JavaCalls::call_static(&result, 108 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 109 vmSymbols::getSystemClassLoader_name(), 110 vmSymbols::void_classloader_signature(), 111 CHECK); 112 113 _java_system_loader = (oop)result.get_jobject(); 114 } 115 116 117 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 118 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 119 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL); 120 } 121 122 // ---------------------------------------------------------------------------- 123 // debugging 124 125 #ifdef ASSERT 126 127 // return true if class_name contains no '.' (internal format is '/') 128 bool SystemDictionary::is_internal_format(Symbol* class_name) { 129 if (class_name != NULL) { 130 ResourceMark rm; 131 char* name = class_name->as_C_string(); 132 return strchr(name, '.') == NULL; 133 } else { 134 return true; 135 } 136 } 137 138 #endif 139 140 // ---------------------------------------------------------------------------- 141 // Parallel class loading check 142 143 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 144 if (UnsyncloadClass || class_loader.is_null()) return true; 145 if (AlwaysLockClassLoader) return false; 146 return java_lang_ClassLoader::parallelCapable(class_loader()); 147 } 148 // ---------------------------------------------------------------------------- 149 // ParallelDefineClass flag does not apply to bootclass loader 150 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 151 if (class_loader.is_null()) return false; 152 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 153 return true; 154 } 155 return false; 156 } 157 158 /** 159 * Returns true if the passed class loader is the extension class loader. 160 */ 161 bool SystemDictionary::is_ext_class_loader(Handle class_loader) { 162 if (class_loader.is_null()) { 163 return false; 164 } 165 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader()); 166 } 167 168 // ---------------------------------------------------------------------------- 169 // Resolving of classes 170 171 // Forwards to resolve_or_null 172 173 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 174 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 175 if (HAS_PENDING_EXCEPTION || klass == NULL) { 176 KlassHandle k_h(THREAD, klass); 177 // can return a null klass 178 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD); 179 } 180 return klass; 181 } 182 183 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 184 bool throw_error, 185 KlassHandle klass_h, TRAPS) { 186 if (HAS_PENDING_EXCEPTION) { 187 // If we have a pending exception we forward it to the caller, unless throw_error is true, 188 // in which case we have to check whether the pending exception is a ClassNotFoundException, 189 // and if so convert it to a NoClassDefFoundError 190 // And chain the original ClassNotFoundException 191 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 192 ResourceMark rm(THREAD); 193 assert(klass_h() == NULL, "Should not have result with exception pending"); 194 Handle e(THREAD, PENDING_EXCEPTION); 195 CLEAR_PENDING_EXCEPTION; 196 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 197 } else { 198 return NULL; 199 } 200 } 201 // Class not found, throw appropriate error or exception depending on value of throw_error 202 if (klass_h() == NULL) { 203 ResourceMark rm(THREAD); 204 if (throw_error) { 205 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 206 } else { 207 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 208 } 209 } 210 return (Klass*)klass_h(); 211 } 212 213 214 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 215 bool throw_error, TRAPS) 216 { 217 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 218 } 219 220 221 // Forwards to resolve_instance_class_or_null 222 223 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 224 assert(!THREAD->is_Compiler_thread(), 225 err_msg("can not load classes with compiler thread: class=%s, classloader=%s", 226 class_name->as_C_string(), 227 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string())); 228 if (FieldType::is_array(class_name)) { 229 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 230 } else if (FieldType::is_obj(class_name)) { 231 ResourceMark rm(THREAD); 232 // Ignore wrapping L and ;. 233 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 234 class_name->utf8_length() - 2, CHECK_NULL); 235 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL); 236 } else { 237 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 238 } 239 } 240 241 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 242 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 243 } 244 245 // Forwards to resolve_instance_class_or_null 246 247 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 248 Handle class_loader, 249 Handle protection_domain, 250 TRAPS) { 251 assert(FieldType::is_array(class_name), "must be array"); 252 Klass* k = NULL; 253 FieldArrayInfo fd; 254 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 255 // of this call 256 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 257 if (t == T_OBJECT) { 258 // naked oop "k" is OK here -- we assign back into it 259 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 260 class_loader, 261 protection_domain, 262 CHECK_NULL); 263 if (k != NULL) { 264 k = k->array_klass(fd.dimension(), CHECK_NULL); 265 } 266 } else { 267 k = Universe::typeArrayKlassObj(t); 268 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 269 } 270 return k; 271 } 272 273 274 // Must be called for any super-class or super-interface resolution 275 // during class definition to allow class circularity checking 276 // super-interface callers: 277 // parse_interfaces - for defineClass & jvmtiRedefineClasses 278 // super-class callers: 279 // ClassFileParser - for defineClass & jvmtiRedefineClasses 280 // load_shared_class - while loading a class from shared archive 281 // resolve_instance_class_or_null: 282 // via: handle_parallel_super_load 283 // when resolving a class that has an existing placeholder with 284 // a saved superclass [i.e. a defineClass is currently in progress] 285 // if another thread is trying to resolve the class, it must do 286 // super-class checks on its own thread to catch class circularity 287 // This last call is critical in class circularity checking for cases 288 // where classloading is delegated to different threads and the 289 // classloader lock is released. 290 // Take the case: Base->Super->Base 291 // 1. If thread T1 tries to do a defineClass of class Base 292 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 293 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 294 // so it tries to load Super 295 // 3. If we load the class internally, or user classloader uses same thread 296 // loadClassFromxxx or defineClass via parseClassFile Super ... 297 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 298 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 299 // 3.4 calls resolve_super_or_fail Base 300 // 3.5 finds T1,Base -> throws class circularity 301 //OR 4. If T2 tries to resolve Super via defineClass Super ... 302 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 303 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 304 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 305 // 4.4 finds T2, Super -> throws class circularity 306 // Must be called, even if superclass is null, since this is 307 // where the placeholder entry is created which claims this 308 // thread is loading this class/classloader. 309 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 310 Symbol* class_name, 311 Handle class_loader, 312 Handle protection_domain, 313 bool is_superclass, 314 TRAPS) { 315 // Double-check, if child class is already loaded, just return super-class,interface 316 // Don't add a placedholder if already loaded, i.e. already in system dictionary 317 // Make sure there's a placeholder for the *child* before resolving. 318 // Used as a claim that this thread is currently loading superclass/classloader 319 // Used here for ClassCircularity checks and also for heap verification 320 // (every InstanceKlass in the heap needs to be in the system dictionary 321 // or have a placeholder). 322 // Must check ClassCircularity before checking if super class is already loaded 323 // 324 // We might not already have a placeholder if this child_name was 325 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 326 // the name of the class might not be known until the stream is actually 327 // parsed. 328 // Bugs 4643874, 4715493 329 // compute_hash can have a safepoint 330 331 ClassLoaderData* loader_data = class_loader_data(class_loader); 332 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 333 int d_index = dictionary()->hash_to_index(d_hash); 334 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 335 int p_index = placeholders()->hash_to_index(p_hash); 336 // can't throw error holding a lock 337 bool child_already_loaded = false; 338 bool throw_circularity_error = false; 339 { 340 MutexLocker mu(SystemDictionary_lock, THREAD); 341 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 342 Klass* quicksuperk; 343 // to support // loading: if child done loading, just return superclass 344 // if class_name, & class_loader don't match: 345 // if initial define, SD update will give LinkageError 346 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 347 // so we don't throw an exception here. 348 // see: nsk redefclass014 & java.lang.instrument Instrument032 349 if ((childk != NULL ) && (is_superclass) && 350 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) && 351 352 ((quicksuperk->name() == class_name) && 353 (quicksuperk->class_loader() == class_loader()))) { 354 return quicksuperk; 355 } else { 356 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 357 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 358 throw_circularity_error = true; 359 } 360 } 361 if (!throw_circularity_error) { 362 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 363 } 364 } 365 if (throw_circularity_error) { 366 ResourceMark rm(THREAD); 367 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 368 } 369 370 // java.lang.Object should have been found above 371 assert(class_name != NULL, "null super class for resolving"); 372 // Resolve the super class or interface, check results on return 373 Klass* superk = SystemDictionary::resolve_or_null(class_name, 374 class_loader, 375 protection_domain, 376 THREAD); 377 378 KlassHandle superk_h(THREAD, superk); 379 380 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 381 // It is no longer necessary to keep the placeholder table alive until update_dictionary 382 // or error. GC used to walk the placeholder table as strong roots. 383 // The instanceKlass is kept alive because the class loader is on the stack, 384 // which keeps the loader_data alive, as well as all instanceKlasses in 385 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 386 { 387 MutexLocker mu(SystemDictionary_lock, THREAD); 388 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 389 SystemDictionary_lock->notify_all(); 390 } 391 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 392 // can null superk 393 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD)); 394 } 395 396 return superk_h(); 397 } 398 399 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 400 Handle class_loader, 401 Handle protection_domain, 402 TRAPS) { 403 if(!has_checkPackageAccess()) return; 404 405 // Now we have to call back to java to check if the initating class has access 406 JavaValue result(T_VOID); 407 if (TraceProtectionDomainVerification) { 408 // Print out trace information 409 tty->print_cr("Checking package access"); 410 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); 411 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); 412 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); 413 } 414 415 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 416 JavaCalls::call_special(&result, 417 class_loader, 418 system_loader, 419 vmSymbols::checkPackageAccess_name(), 420 vmSymbols::class_protectiondomain_signature(), 421 Handle(THREAD, klass->java_mirror()), 422 protection_domain, 423 THREAD); 424 425 if (TraceProtectionDomainVerification) { 426 if (HAS_PENDING_EXCEPTION) { 427 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); 428 } else { 429 tty->print_cr(" -> granted"); 430 } 431 tty->cr(); 432 } 433 434 if (HAS_PENDING_EXCEPTION) return; 435 436 // If no exception has been thrown, we have validated the protection domain 437 // Insert the protection domain of the initiating class into the set. 438 { 439 // We recalculate the entry here -- we've called out to java since 440 // the last time it was calculated. 441 ClassLoaderData* loader_data = class_loader_data(class_loader); 442 443 Symbol* kn = klass->name(); 444 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 445 int d_index = dictionary()->hash_to_index(d_hash); 446 447 MutexLocker mu(SystemDictionary_lock, THREAD); 448 { 449 // Note that we have an entry, and entries can be deleted only during GC, 450 // so we cannot allow GC to occur while we're holding this entry. 451 452 // We're using a No_Safepoint_Verifier to catch any place where we 453 // might potentially do a GC at all. 454 // Dictionary::do_unloading() asserts that classes in SD are only 455 // unloaded at a safepoint. Anonymous classes are not in SD. 456 No_Safepoint_Verifier nosafepoint; 457 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 458 protection_domain, THREAD); 459 } 460 } 461 } 462 463 // We only get here if this thread finds that another thread 464 // has already claimed the placeholder token for the current operation, 465 // but that other thread either never owned or gave up the 466 // object lock 467 // Waits on SystemDictionary_lock to indicate placeholder table updated 468 // On return, caller must recheck placeholder table state 469 // 470 // We only get here if 471 // 1) custom classLoader, i.e. not bootstrap classloader 472 // 2) UnsyncloadClass not set 473 // 3) custom classLoader has broken the class loader objectLock 474 // so another thread got here in parallel 475 // 476 // lockObject must be held. 477 // Complicated dance due to lock ordering: 478 // Must first release the classloader object lock to 479 // allow initial definer to complete the class definition 480 // and to avoid deadlock 481 // Reclaim classloader lock object with same original recursion count 482 // Must release SystemDictionary_lock after notify, since 483 // class loader lock must be claimed before SystemDictionary_lock 484 // to prevent deadlocks 485 // 486 // The notify allows applications that did an untimed wait() on 487 // the classloader object lock to not hang. 488 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 489 assert_lock_strong(SystemDictionary_lock); 490 491 bool calledholdinglock 492 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 493 assert(calledholdinglock,"must hold lock for notify"); 494 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 495 ObjectSynchronizer::notifyall(lockObject, THREAD); 496 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 497 SystemDictionary_lock->wait(); 498 SystemDictionary_lock->unlock(); 499 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 500 SystemDictionary_lock->lock(); 501 } 502 503 // If the class in is in the placeholder table, class loading is in progress 504 // For cases where the application changes threads to load classes, it 505 // is critical to ClassCircularity detection that we try loading 506 // the superclass on the same thread internally, so we do parallel 507 // super class loading here. 508 // This also is critical in cases where the original thread gets stalled 509 // even in non-circularity situations. 510 // Note: must call resolve_super_or_fail even if null super - 511 // to force placeholder entry creation for this class for circularity detection 512 // Caller must check for pending exception 513 // Returns non-null Klass* if other thread has completed load 514 // and we are done, 515 // If return null Klass* and no pending exception, the caller must load the class 516 instanceKlassHandle SystemDictionary::handle_parallel_super_load( 517 Symbol* name, Symbol* superclassname, Handle class_loader, 518 Handle protection_domain, Handle lockObject, TRAPS) { 519 520 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 521 ClassLoaderData* loader_data = class_loader_data(class_loader); 522 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 523 int d_index = dictionary()->hash_to_index(d_hash); 524 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 525 int p_index = placeholders()->hash_to_index(p_hash); 526 527 // superk is not used, resolve_super called for circularity check only 528 // This code is reached in two situations. One if this thread 529 // is loading the same class twice (e.g. ClassCircularity, or 530 // java.lang.instrument). 531 // The second is if another thread started the resolve_super first 532 // and has not yet finished. 533 // In both cases the original caller will clean up the placeholder 534 // entry on error. 535 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 536 superclassname, 537 class_loader, 538 protection_domain, 539 true, 540 CHECK_(nh)); 541 542 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 543 // Serial class loaders and bootstrap classloader do wait for superclass loads 544 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 545 MutexLocker mu(SystemDictionary_lock, THREAD); 546 // Check if classloading completed while we were loading superclass or waiting 547 Klass* check = find_class(d_index, d_hash, name, loader_data); 548 if (check != NULL) { 549 // Klass is already loaded, so just return it 550 return(instanceKlassHandle(THREAD, check)); 551 } else { 552 return nh; 553 } 554 } 555 556 // must loop to both handle other placeholder updates 557 // and spurious notifications 558 bool super_load_in_progress = true; 559 PlaceholderEntry* placeholder; 560 while (super_load_in_progress) { 561 MutexLocker mu(SystemDictionary_lock, THREAD); 562 // Check if classloading completed while we were loading superclass or waiting 563 Klass* check = find_class(d_index, d_hash, name, loader_data); 564 if (check != NULL) { 565 // Klass is already loaded, so just return it 566 return(instanceKlassHandle(THREAD, check)); 567 } else { 568 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 569 if (placeholder && placeholder->super_load_in_progress() ){ 570 // Before UnsyncloadClass: 571 // We only get here if the application has released the 572 // classloader lock when another thread was in the middle of loading a 573 // superclass/superinterface for this class, and now 574 // this thread is also trying to load this class. 575 // To minimize surprises, the first thread that started to 576 // load a class should be the one to complete the loading 577 // with the classfile it initially expected. 578 // This logic has the current thread wait once it has done 579 // all the superclass/superinterface loading it can, until 580 // the original thread completes the class loading or fails 581 // If it completes we will use the resulting InstanceKlass 582 // which we will find below in the systemDictionary. 583 // We also get here for parallel bootstrap classloader 584 if (class_loader.is_null()) { 585 SystemDictionary_lock->wait(); 586 } else { 587 double_lock_wait(lockObject, THREAD); 588 } 589 } else { 590 // If not in SD and not in PH, other thread's load must have failed 591 super_load_in_progress = false; 592 } 593 } 594 } 595 return (nh); 596 } 597 598 599 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 600 Handle class_loader, 601 Handle protection_domain, 602 TRAPS) { 603 assert(name != NULL && !FieldType::is_array(name) && 604 !FieldType::is_obj(name), "invalid class name"); 605 606 Ticks class_load_start_time = Ticks::now(); 607 608 // Fix for 4474172; see evaluation for more details 609 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 610 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 611 612 // Do lookup to see if class already exist and the protection domain 613 // has the right access 614 // This call uses find which checks protection domain already matches 615 // All subsequent calls use find_class, and set has_loaded_class so that 616 // before we return a result we call out to java to check for valid protection domain 617 // to allow returning the Klass* and add it to the pd_set if it is valid 618 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 619 int d_index = dictionary()->hash_to_index(d_hash); 620 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 621 protection_domain, THREAD); 622 if (probe != NULL) return probe; 623 624 625 // Non-bootstrap class loaders will call out to class loader and 626 // define via jvm/jni_DefineClass which will acquire the 627 // class loader object lock to protect against multiple threads 628 // defining the class in parallel by accident. 629 // This lock must be acquired here so the waiter will find 630 // any successful result in the SystemDictionary and not attempt 631 // the define 632 // ParallelCapable Classloaders and the bootstrap classloader, 633 // or all classloaders with UnsyncloadClass do not acquire lock here 634 bool DoObjectLock = true; 635 if (is_parallelCapable(class_loader)) { 636 DoObjectLock = false; 637 } 638 639 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 640 int p_index = placeholders()->hash_to_index(p_hash); 641 642 // Class is not in SystemDictionary so we have to do loading. 643 // Make sure we are synchronized on the class loader before we proceed 644 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 645 check_loader_lock_contention(lockObject, THREAD); 646 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 647 648 // Check again (after locking) if class already exist in SystemDictionary 649 bool class_has_been_loaded = false; 650 bool super_load_in_progress = false; 651 bool havesupername = false; 652 instanceKlassHandle k; 653 PlaceholderEntry* placeholder; 654 Symbol* superclassname = NULL; 655 656 { 657 MutexLocker mu(SystemDictionary_lock, THREAD); 658 Klass* check = find_class(d_index, d_hash, name, loader_data); 659 if (check != NULL) { 660 // Klass is already loaded, so just return it 661 class_has_been_loaded = true; 662 k = instanceKlassHandle(THREAD, check); 663 } else { 664 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 665 if (placeholder && placeholder->super_load_in_progress()) { 666 super_load_in_progress = true; 667 if (placeholder->havesupername() == true) { 668 superclassname = placeholder->supername(); 669 havesupername = true; 670 } 671 } 672 } 673 } 674 675 // If the class is in the placeholder table, class loading is in progress 676 if (super_load_in_progress && havesupername==true) { 677 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 678 class_loader, protection_domain, lockObject, THREAD); 679 if (HAS_PENDING_EXCEPTION) { 680 return NULL; 681 } 682 if (!k.is_null()) { 683 class_has_been_loaded = true; 684 } 685 } 686 687 bool throw_circularity_error = false; 688 if (!class_has_been_loaded) { 689 bool load_instance_added = false; 690 691 // add placeholder entry to record loading instance class 692 // Five cases: 693 // All cases need to prevent modifying bootclasssearchpath 694 // in parallel with a classload of same classname 695 // Redefineclasses uses existence of the placeholder for the duration 696 // of the class load to prevent concurrent redefinition of not completely 697 // defined classes. 698 // case 1. traditional classloaders that rely on the classloader object lock 699 // - no other need for LOAD_INSTANCE 700 // case 2. traditional classloaders that break the classloader object lock 701 // as a deadlock workaround. Detection of this case requires that 702 // this check is done while holding the classloader object lock, 703 // and that lock is still held when calling classloader's loadClass. 704 // For these classloaders, we ensure that the first requestor 705 // completes the load and other requestors wait for completion. 706 // case 3. UnsyncloadClass - don't use objectLocker 707 // With this flag, we allow parallel classloading of a 708 // class/classloader pair 709 // case4. Bootstrap classloader - don't own objectLocker 710 // This classloader supports parallelism at the classloader level, 711 // but only allows a single load of a class/classloader pair. 712 // No performance benefit and no deadlock issues. 713 // case 5. parallelCapable user level classloaders - without objectLocker 714 // Allow parallel classloading of a class/classloader pair 715 716 { 717 MutexLocker mu(SystemDictionary_lock, THREAD); 718 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 719 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 720 if (oldprobe) { 721 // only need check_seen_thread once, not on each loop 722 // 6341374 java/lang/Instrument with -Xcomp 723 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 724 throw_circularity_error = true; 725 } else { 726 // case 1: traditional: should never see load_in_progress. 727 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 728 729 // case 4: bootstrap classloader: prevent futile classloading, 730 // wait on first requestor 731 if (class_loader.is_null()) { 732 SystemDictionary_lock->wait(); 733 } else { 734 // case 2: traditional with broken classloader lock. wait on first 735 // requestor. 736 double_lock_wait(lockObject, THREAD); 737 } 738 // Check if classloading completed while we were waiting 739 Klass* check = find_class(d_index, d_hash, name, loader_data); 740 if (check != NULL) { 741 // Klass is already loaded, so just return it 742 k = instanceKlassHandle(THREAD, check); 743 class_has_been_loaded = true; 744 } 745 // check if other thread failed to load and cleaned up 746 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 747 } 748 } 749 } 750 } 751 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 752 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 753 // LOAD_INSTANCE in parallel 754 755 if (!throw_circularity_error && !class_has_been_loaded) { 756 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 757 load_instance_added = true; 758 // For class loaders that do not acquire the classloader object lock, 759 // if they did not catch another thread holding LOAD_INSTANCE, 760 // need a check analogous to the acquire ObjectLocker/find_class 761 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 762 // one final check if the load has already completed 763 // class loaders holding the ObjectLock shouldn't find the class here 764 Klass* check = find_class(d_index, d_hash, name, loader_data); 765 if (check != NULL) { 766 // Klass is already loaded, so return it after checking/adding protection domain 767 k = instanceKlassHandle(THREAD, check); 768 class_has_been_loaded = true; 769 } 770 } 771 } 772 773 // must throw error outside of owning lock 774 if (throw_circularity_error) { 775 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 776 ResourceMark rm(THREAD); 777 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 778 } 779 780 if (!class_has_been_loaded) { 781 782 // Do actual loading 783 k = load_instance_class(name, class_loader, THREAD); 784 785 // For UnsyncloadClass only 786 // If they got a linkageError, check if a parallel class load succeeded. 787 // If it did, then for bytecode resolution the specification requires 788 // that we return the same result we did for the other thread, i.e. the 789 // successfully loaded InstanceKlass 790 // Should not get here for classloaders that support parallelism 791 // with the new cleaner mechanism, even with AllowParallelDefineClass 792 // Bootstrap goes through here to allow for an extra guarantee check 793 if (UnsyncloadClass || (class_loader.is_null())) { 794 if (k.is_null() && HAS_PENDING_EXCEPTION 795 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 796 MutexLocker mu(SystemDictionary_lock, THREAD); 797 Klass* check = find_class(d_index, d_hash, name, loader_data); 798 if (check != NULL) { 799 // Klass is already loaded, so just use it 800 k = instanceKlassHandle(THREAD, check); 801 CLEAR_PENDING_EXCEPTION; 802 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 803 } 804 } 805 } 806 807 // If everything was OK (no exceptions, no null return value), and 808 // class_loader is NOT the defining loader, do a little more bookkeeping. 809 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 810 k->class_loader() != class_loader()) { 811 812 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 813 814 // Need to check for a PENDING_EXCEPTION again; check_constraints 815 // can throw and doesn't use the CHECK macro. 816 if (!HAS_PENDING_EXCEPTION) { 817 { // Grabbing the Compile_lock prevents systemDictionary updates 818 // during compilations. 819 MutexLocker mu(Compile_lock, THREAD); 820 update_dictionary(d_index, d_hash, p_index, p_hash, 821 k, class_loader, THREAD); 822 } 823 824 if (JvmtiExport::should_post_class_load()) { 825 Thread *thread = THREAD; 826 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 827 JvmtiExport::post_class_load((JavaThread *) thread, k()); 828 } 829 } 830 } 831 } // load_instance_class loop 832 833 if (load_instance_added == true) { 834 // clean up placeholder entries for LOAD_INSTANCE success or error 835 // This brackets the SystemDictionary updates for both defining 836 // and initiating loaders 837 MutexLocker mu(SystemDictionary_lock, THREAD); 838 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 839 SystemDictionary_lock->notify_all(); 840 } 841 } 842 843 if (HAS_PENDING_EXCEPTION || k.is_null()) { 844 return NULL; 845 } 846 847 post_class_load_event(class_load_start_time, k, class_loader); 848 849 #ifdef ASSERT 850 { 851 ClassLoaderData* loader_data = k->class_loader_data(); 852 MutexLocker mu(SystemDictionary_lock, THREAD); 853 Klass* kk = find_class(name, loader_data); 854 assert(kk == k(), "should be present in dictionary"); 855 } 856 #endif 857 858 // return if the protection domain in NULL 859 if (protection_domain() == NULL) return k(); 860 861 // Check the protection domain has the right access 862 { 863 MutexLocker mu(SystemDictionary_lock, THREAD); 864 // Note that we have an entry, and entries can be deleted only during GC, 865 // so we cannot allow GC to occur while we're holding this entry. 866 // We're using a No_Safepoint_Verifier to catch any place where we 867 // might potentially do a GC at all. 868 // Dictionary::do_unloading() asserts that classes in SD are only 869 // unloaded at a safepoint. Anonymous classes are not in SD. 870 No_Safepoint_Verifier nosafepoint; 871 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 872 loader_data, 873 protection_domain)) { 874 return k(); 875 } 876 } 877 878 // Verify protection domain. If it fails an exception is thrown 879 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 880 881 return k(); 882 } 883 884 885 // This routine does not lock the system dictionary. 886 // 887 // Since readers don't hold a lock, we must make sure that system 888 // dictionary entries are only removed at a safepoint (when only one 889 // thread is running), and are added to in a safe way (all links must 890 // be updated in an MT-safe manner). 891 // 892 // Callers should be aware that an entry could be added just after 893 // _dictionary->bucket(index) is read here, so the caller will not see 894 // the new entry. 895 896 Klass* SystemDictionary::find(Symbol* class_name, 897 Handle class_loader, 898 Handle protection_domain, 899 TRAPS) { 900 901 // The result of this call should be consistent with the result 902 // of the call to resolve_instance_class_or_null(). 903 // See evaluation 6790209 and 4474172 for more details. 904 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 905 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 906 907 if (loader_data == NULL) { 908 // If the ClassLoaderData has not been setup, 909 // then the class loader has no entries in the dictionary. 910 return NULL; 911 } 912 913 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 914 int d_index = dictionary()->hash_to_index(d_hash); 915 916 { 917 // Note that we have an entry, and entries can be deleted only during GC, 918 // so we cannot allow GC to occur while we're holding this entry. 919 // We're using a No_Safepoint_Verifier to catch any place where we 920 // might potentially do a GC at all. 921 // Dictionary::do_unloading() asserts that classes in SD are only 922 // unloaded at a safepoint. Anonymous classes are not in SD. 923 No_Safepoint_Verifier nosafepoint; 924 return dictionary()->find(d_index, d_hash, class_name, loader_data, 925 protection_domain, THREAD); 926 } 927 } 928 929 930 // Look for a loaded instance or array klass by name. Do not do any loading. 931 // return NULL in case of error. 932 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 933 Handle class_loader, 934 Handle protection_domain, 935 TRAPS) { 936 Klass* k = NULL; 937 assert(class_name != NULL, "class name must be non NULL"); 938 939 if (FieldType::is_array(class_name)) { 940 // The name refers to an array. Parse the name. 941 // dimension and object_key in FieldArrayInfo are assigned as a 942 // side-effect of this call 943 FieldArrayInfo fd; 944 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 945 if (t != T_OBJECT) { 946 k = Universe::typeArrayKlassObj(t); 947 } else { 948 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 949 } 950 if (k != NULL) { 951 k = k->array_klass_or_null(fd.dimension()); 952 } 953 } else { 954 k = find(class_name, class_loader, protection_domain, THREAD); 955 } 956 return k; 957 } 958 959 // Note: this method is much like resolve_from_stream, but 960 // updates no supplemental data structures. 961 // TODO consolidate the two methods with a helper routine? 962 Klass* SystemDictionary::parse_stream(Symbol* class_name, 963 Handle class_loader, 964 Handle protection_domain, 965 ClassFileStream* st, 966 KlassHandle host_klass, 967 GrowableArray<Handle>* cp_patches, 968 TRAPS) { 969 TempNewSymbol parsed_name = NULL; 970 971 Ticks class_load_start_time = Ticks::now(); 972 973 ClassLoaderData* loader_data; 974 if (host_klass.not_null()) { 975 // Create a new CLD for anonymous class, that uses the same class loader 976 // as the host_klass 977 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 978 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 979 loader_data->record_dependency(host_klass(), CHECK_NULL); 980 } else { 981 loader_data = ClassLoaderData::class_loader_data(class_loader()); 982 } 983 984 // Parse the stream. Note that we do this even though this klass might 985 // already be present in the SystemDictionary, otherwise we would not 986 // throw potential ClassFormatErrors. 987 // 988 // Note: "name" is updated. 989 990 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 991 loader_data, 992 protection_domain, 993 host_klass, 994 cp_patches, 995 parsed_name, 996 true, 997 THREAD); 998 999 1000 if (host_klass.not_null() && k.not_null()) { 1001 // If it's anonymous, initialize it now, since nobody else will. 1002 1003 { 1004 MutexLocker mu_r(Compile_lock, THREAD); 1005 1006 // Add to class hierarchy, initialize vtables, and do possible 1007 // deoptimizations. 1008 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1009 1010 // But, do not add to system dictionary. 1011 1012 // compiled code dependencies need to be validated anyway 1013 notice_modification(); 1014 } 1015 1016 // Rewrite and patch constant pool here. 1017 k->link_class(CHECK_NULL); 1018 if (cp_patches != NULL) { 1019 k->constants()->patch_resolved_references(cp_patches); 1020 } 1021 k->eager_initialize(CHECK_NULL); 1022 1023 // notify jvmti 1024 if (JvmtiExport::should_post_class_load()) { 1025 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1026 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1027 } 1028 1029 post_class_load_event(class_load_start_time, k, class_loader); 1030 } 1031 assert(host_klass.not_null() || cp_patches == NULL, 1032 "cp_patches only found with host_klass"); 1033 1034 return k(); 1035 } 1036 1037 // Add a klass to the system from a stream (called by jni_DefineClass and 1038 // JVM_DefineClass). 1039 // Note: class_name can be NULL. In that case we do not know the name of 1040 // the class until we have parsed the stream. 1041 1042 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1043 Handle class_loader, 1044 Handle protection_domain, 1045 ClassFileStream* st, 1046 bool verify, 1047 TRAPS) { 1048 1049 // Classloaders that support parallelism, e.g. bootstrap classloader, 1050 // or all classloaders with UnsyncloadClass do not acquire lock here 1051 bool DoObjectLock = true; 1052 if (is_parallelCapable(class_loader)) { 1053 DoObjectLock = false; 1054 } 1055 1056 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1057 1058 // Make sure we are synchronized on the class loader before we proceed 1059 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1060 check_loader_lock_contention(lockObject, THREAD); 1061 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1062 1063 TempNewSymbol parsed_name = NULL; 1064 1065 // Parse the stream. Note that we do this even though this klass might 1066 // already be present in the SystemDictionary, otherwise we would not 1067 // throw potential ClassFormatErrors. 1068 // 1069 // Note: "name" is updated. 1070 1071 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1072 loader_data, 1073 protection_domain, 1074 parsed_name, 1075 verify, 1076 THREAD); 1077 1078 const char* pkg = "java/"; 1079 if (!HAS_PENDING_EXCEPTION && 1080 !class_loader.is_null() && 1081 parsed_name != NULL && 1082 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1083 // It is illegal to define classes in the "java." package from 1084 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1085 ResourceMark rm(THREAD); 1086 char* name = parsed_name->as_C_string(); 1087 char* index = strrchr(name, '/'); 1088 *index = '\0'; // chop to just the package name 1089 while ((index = strchr(name, '/')) != NULL) { 1090 *index = '.'; // replace '/' with '.' in package name 1091 } 1092 const char* fmt = "Prohibited package name: %s"; 1093 size_t len = strlen(fmt) + strlen(name); 1094 char* message = NEW_RESOURCE_ARRAY(char, len); 1095 jio_snprintf(message, len, fmt, name); 1096 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1097 vmSymbols::java_lang_SecurityException(), message); 1098 } 1099 1100 if (!HAS_PENDING_EXCEPTION) { 1101 assert(parsed_name != NULL, "Sanity"); 1102 assert(class_name == NULL || class_name == parsed_name, "name mismatch"); 1103 // Verification prevents us from creating names with dots in them, this 1104 // asserts that that's the case. 1105 assert(is_internal_format(parsed_name), 1106 "external class name format used internally"); 1107 1108 // Add class just loaded 1109 // If a class loader supports parallel classloading handle parallel define requests 1110 // find_or_define_instance_class may return a different InstanceKlass 1111 if (is_parallelCapable(class_loader)) { 1112 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); 1113 } else { 1114 define_instance_class(k, THREAD); 1115 } 1116 } 1117 1118 // Make sure we have an entry in the SystemDictionary on success 1119 debug_only( { 1120 if (!HAS_PENDING_EXCEPTION) { 1121 assert(parsed_name != NULL, "parsed_name is still null?"); 1122 Symbol* h_name = k->name(); 1123 ClassLoaderData *defining_loader_data = k->class_loader_data(); 1124 1125 MutexLocker mu(SystemDictionary_lock, THREAD); 1126 1127 Klass* check = find_class(parsed_name, loader_data); 1128 assert(check == k(), "should be present in the dictionary"); 1129 1130 Klass* check2 = find_class(h_name, defining_loader_data); 1131 assert(check == check2, "name inconsistancy in SystemDictionary"); 1132 } 1133 } ); 1134 1135 return k(); 1136 } 1137 1138 1139 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1140 int number_of_entries) { 1141 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1142 "bad shared dictionary size."); 1143 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1144 } 1145 1146 1147 // If there is a shared dictionary, then find the entry for the 1148 // given shared system class, if any. 1149 1150 Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1151 if (shared_dictionary() != NULL) { 1152 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1153 int d_index = shared_dictionary()->hash_to_index(d_hash); 1154 1155 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1156 } else { 1157 return NULL; 1158 } 1159 } 1160 1161 1162 // Load a class from the shared spaces (found through the shared system 1163 // dictionary). Force the superclass and all interfaces to be loaded. 1164 // Update the class definition to include sibling classes and no 1165 // subclasses (yet). [Classes in the shared space are not part of the 1166 // object hierarchy until loaded.] 1167 1168 instanceKlassHandle SystemDictionary::load_shared_class( 1169 Symbol* class_name, Handle class_loader, TRAPS) { 1170 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1171 return load_shared_class(ik, class_loader, THREAD); 1172 } 1173 1174 instanceKlassHandle SystemDictionary::load_shared_class( 1175 instanceKlassHandle ik, Handle class_loader, TRAPS) { 1176 assert(class_loader.is_null(), "non-null classloader for shared class?"); 1177 if (ik.not_null()) { 1178 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1179 Symbol* class_name = ik->name(); 1180 1181 // Found the class, now load the superclass and interfaces. If they 1182 // are shared, add them to the main system dictionary and reset 1183 // their hierarchy references (supers, subs, and interfaces). 1184 1185 if (ik->super() != NULL) { 1186 Symbol* cn = ik->super()->name(); 1187 resolve_super_or_fail(class_name, cn, 1188 class_loader, Handle(), true, CHECK_(nh)); 1189 } 1190 1191 Array<Klass*>* interfaces = ik->local_interfaces(); 1192 int num_interfaces = interfaces->length(); 1193 for (int index = 0; index < num_interfaces; index++) { 1194 Klass* k = interfaces->at(index); 1195 1196 // Note: can not use InstanceKlass::cast here because 1197 // interfaces' InstanceKlass's C++ vtbls haven't been 1198 // reinitialized yet (they will be once the interface classes 1199 // are loaded) 1200 Symbol* name = k->name(); 1201 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); 1202 } 1203 1204 // Adjust methods to recover missing data. They need addresses for 1205 // interpreter entry points and their default native method address 1206 // must be reset. 1207 1208 // Updating methods must be done under a lock so multiple 1209 // threads don't update these in parallel 1210 // Shared classes are all currently loaded by the bootstrap 1211 // classloader, so this will never cause a deadlock on 1212 // a custom class loader lock. 1213 1214 { 1215 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1216 check_loader_lock_contention(lockObject, THREAD); 1217 ObjectLocker ol(lockObject, THREAD, true); 1218 ik->restore_unshareable_info(CHECK_(nh)); 1219 } 1220 1221 if (TraceClassLoading) { 1222 ResourceMark rm; 1223 tty->print("[Loaded %s", ik->external_name()); 1224 tty->print(" from shared objects file"); 1225 tty->print_cr("]"); 1226 } 1227 // notify a class loaded from shared object 1228 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()), 1229 true /* shared class */); 1230 } 1231 return ik; 1232 } 1233 1234 1235 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1236 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1237 if (class_loader.is_null()) { 1238 1239 // Search the shared system dictionary for classes preloaded into the 1240 // shared spaces. 1241 instanceKlassHandle k; 1242 { 1243 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1244 k = load_shared_class(class_name, class_loader, THREAD); 1245 } 1246 1247 if (k.is_null()) { 1248 // Use VM class loader 1249 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1250 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); 1251 } 1252 1253 // find_or_define_instance_class may return a different InstanceKlass 1254 if (!k.is_null()) { 1255 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1256 } 1257 return k; 1258 } else { 1259 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1260 ResourceMark rm(THREAD); 1261 1262 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1263 JavaThread* jt = (JavaThread*) THREAD; 1264 1265 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1266 ClassLoader::perf_app_classload_selftime(), 1267 ClassLoader::perf_app_classload_count(), 1268 jt->get_thread_stat()->perf_recursion_counts_addr(), 1269 jt->get_thread_stat()->perf_timers_addr(), 1270 PerfClassTraceTime::CLASS_LOAD); 1271 1272 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1273 // Translate to external class name format, i.e., convert '/' chars to '.' 1274 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1275 1276 JavaValue result(T_OBJECT); 1277 1278 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1279 1280 // Call public unsynchronized loadClass(String) directly for all class loaders 1281 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1282 // acquire a class-name based lock rather than the class loader object lock. 1283 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1284 // so the call to loadClassInternal() was not required. 1285 // 1286 // UnsyncloadClass flag means both call loadClass(String) and do 1287 // not acquire the class loader lock even for class loaders that are 1288 // not parallelCapable. This was a risky transitional 1289 // flag for diagnostic purposes only. It is risky to call 1290 // custom class loaders without synchronization. 1291 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1292 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1293 // Do NOT assume this will be supported in future releases. 1294 // 1295 // Added MustCallLoadClassInternal in case we discover in the field 1296 // a customer that counts on this call 1297 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1298 JavaCalls::call_special(&result, 1299 class_loader, 1300 spec_klass, 1301 vmSymbols::loadClassInternal_name(), 1302 vmSymbols::string_class_signature(), 1303 string, 1304 CHECK_(nh)); 1305 } else { 1306 JavaCalls::call_virtual(&result, 1307 class_loader, 1308 spec_klass, 1309 vmSymbols::loadClass_name(), 1310 vmSymbols::string_class_signature(), 1311 string, 1312 CHECK_(nh)); 1313 } 1314 1315 assert(result.get_type() == T_OBJECT, "just checking"); 1316 oop obj = (oop) result.get_jobject(); 1317 1318 // Primitive classes return null since forName() can not be 1319 // used to obtain any of the Class objects representing primitives or void 1320 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1321 instanceKlassHandle k = 1322 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1323 // For user defined Java class loaders, check that the name returned is 1324 // the same as that requested. This check is done for the bootstrap 1325 // loader when parsing the class file. 1326 if (class_name == k->name()) { 1327 return k; 1328 } 1329 } 1330 // Class is not found or has the wrong name, return NULL 1331 return nh; 1332 } 1333 } 1334 1335 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1336 1337 ClassLoaderData* loader_data = k->class_loader_data(); 1338 Handle class_loader_h(THREAD, loader_data->class_loader()); 1339 1340 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){} 1341 1342 // for bootstrap and other parallel classloaders don't acquire lock, 1343 // use placeholder token 1344 // If a parallelCapable class loader calls define_instance_class instead of 1345 // find_or_define_instance_class to get here, we have a timing 1346 // hole with systemDictionary updates and check_constraints 1347 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1348 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1349 compute_loader_lock_object(class_loader_h, THREAD)), 1350 "define called without lock"); 1351 } 1352 1353 // Check class-loading constraints. Throw exception if violation is detected. 1354 // Grabs and releases SystemDictionary_lock 1355 // The check_constraints/find_class call and update_dictionary sequence 1356 // must be "atomic" for a specific class/classloader pair so we never 1357 // define two different instanceKlasses for that class/classloader pair. 1358 // Existing classloaders will call define_instance_class with the 1359 // classloader lock held 1360 // Parallel classloaders will call find_or_define_instance_class 1361 // which will require a token to perform the define class 1362 Symbol* name_h = k->name(); 1363 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1364 int d_index = dictionary()->hash_to_index(d_hash); 1365 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1366 1367 // Register class just loaded with class loader (placed in Vector) 1368 // Note we do this before updating the dictionary, as this can 1369 // fail with an OutOfMemoryError (if it does, we will *not* put this 1370 // class in the dictionary and will not update the class hierarchy). 1371 // JVMTI FollowReferences needs to find the classes this way. 1372 if (k->class_loader() != NULL) { 1373 methodHandle m(THREAD, Universe::loader_addClass_method()); 1374 JavaValue result(T_VOID); 1375 JavaCallArguments args(class_loader_h); 1376 args.push_oop(Handle(THREAD, k->java_mirror())); 1377 JavaCalls::call(&result, m, &args, CHECK); 1378 } 1379 1380 // Add the new class. We need recompile lock during update of CHA. 1381 { 1382 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1383 int p_index = placeholders()->hash_to_index(p_hash); 1384 1385 MutexLocker mu_r(Compile_lock, THREAD); 1386 1387 // Add to class hierarchy, initialize vtables, and do possible 1388 // deoptimizations. 1389 add_to_hierarchy(k, CHECK); // No exception, but can block 1390 1391 // Add to systemDictionary - so other classes can see it. 1392 // Grabs and releases SystemDictionary_lock 1393 update_dictionary(d_index, d_hash, p_index, p_hash, 1394 k, class_loader_h, THREAD); 1395 } 1396 k->eager_initialize(THREAD); 1397 1398 // notify jvmti 1399 if (JvmtiExport::should_post_class_load()) { 1400 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1401 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1402 1403 } 1404 1405 } 1406 1407 // Support parallel classloading 1408 // All parallel class loaders, including bootstrap classloader 1409 // lock a placeholder entry for this class/class_loader pair 1410 // to allow parallel defines of different classes for this class loader 1411 // With AllowParallelDefine flag==true, in case they do not synchronize around 1412 // FindLoadedClass/DefineClass, calls, we check for parallel 1413 // loading for them, wait if a defineClass is in progress 1414 // and return the initial requestor's results 1415 // This flag does not apply to the bootstrap classloader. 1416 // With AllowParallelDefine flag==false, call through to define_instance_class 1417 // which will throw LinkageError: duplicate class definition. 1418 // False is the requested default. 1419 // For better performance, the class loaders should synchronize 1420 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1421 // potentially waste time reading and parsing the bytestream. 1422 // Note: VM callers should ensure consistency of k/class_name,class_loader 1423 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1424 1425 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1426 Symbol* name_h = k->name(); // passed in class_name may be null 1427 ClassLoaderData* loader_data = class_loader_data(class_loader); 1428 1429 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1430 int d_index = dictionary()->hash_to_index(d_hash); 1431 1432 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1433 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1434 int p_index = placeholders()->hash_to_index(p_hash); 1435 PlaceholderEntry* probe; 1436 1437 { 1438 MutexLocker mu(SystemDictionary_lock, THREAD); 1439 // First check if class already defined 1440 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1441 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1442 if (check != NULL) { 1443 return(instanceKlassHandle(THREAD, check)); 1444 } 1445 } 1446 1447 // Acquire define token for this class/classloader 1448 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1449 // Wait if another thread defining in parallel 1450 // All threads wait - even those that will throw duplicate class: otherwise 1451 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1452 // if other thread has not finished updating dictionary 1453 while (probe->definer() != NULL) { 1454 SystemDictionary_lock->wait(); 1455 } 1456 // Only special cases allow parallel defines and can use other thread's results 1457 // Other cases fall through, and may run into duplicate defines 1458 // caught by finding an entry in the SystemDictionary 1459 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1460 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1461 SystemDictionary_lock->notify_all(); 1462 #ifdef ASSERT 1463 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1464 assert(check != NULL, "definer missed recording success"); 1465 #endif 1466 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1467 } else { 1468 // This thread will define the class (even if earlier thread tried and had an error) 1469 probe->set_definer(THREAD); 1470 } 1471 } 1472 1473 define_instance_class(k, THREAD); 1474 1475 Handle linkage_exception = Handle(); // null handle 1476 1477 // definer must notify any waiting threads 1478 { 1479 MutexLocker mu(SystemDictionary_lock, THREAD); 1480 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1481 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1482 if (probe != NULL) { 1483 if (HAS_PENDING_EXCEPTION) { 1484 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1485 CLEAR_PENDING_EXCEPTION; 1486 } else { 1487 probe->set_instance_klass(k()); 1488 } 1489 probe->set_definer(NULL); 1490 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1491 SystemDictionary_lock->notify_all(); 1492 } 1493 } 1494 1495 // Can't throw exception while holding lock due to rank ordering 1496 if (linkage_exception() != NULL) { 1497 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1498 } 1499 1500 return k; 1501 } 1502 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1503 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1504 if (class_loader.is_null()) { 1505 return Handle(THREAD, _system_loader_lock_obj); 1506 } else { 1507 return class_loader; 1508 } 1509 } 1510 1511 // This method is added to check how often we have to wait to grab loader 1512 // lock. The results are being recorded in the performance counters defined in 1513 // ClassLoader::_sync_systemLoaderLockContentionRate and 1514 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1515 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1516 if (!UsePerfData) { 1517 return; 1518 } 1519 1520 assert(!loader_lock.is_null(), "NULL lock object"); 1521 1522 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1523 == ObjectSynchronizer::owner_other) { 1524 // contention will likely happen, so increment the corresponding 1525 // contention counter. 1526 if (loader_lock() == _system_loader_lock_obj) { 1527 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1528 } else { 1529 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1530 } 1531 } 1532 } 1533 1534 // ---------------------------------------------------------------------------- 1535 // Lookup 1536 1537 Klass* SystemDictionary::find_class(int index, unsigned int hash, 1538 Symbol* class_name, 1539 ClassLoaderData* loader_data) { 1540 assert_locked_or_safepoint(SystemDictionary_lock); 1541 assert (index == dictionary()->index_for(class_name, loader_data), 1542 "incorrect index?"); 1543 1544 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1545 return k; 1546 } 1547 1548 1549 // Basic find on classes in the midst of being loaded 1550 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1551 ClassLoaderData* loader_data) { 1552 assert_locked_or_safepoint(SystemDictionary_lock); 1553 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1554 int p_index = placeholders()->hash_to_index(p_hash); 1555 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1556 } 1557 1558 1559 // Used for assertions and verification only 1560 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1561 #ifndef ASSERT 1562 guarantee(VerifyBeforeGC || 1563 VerifyDuringGC || 1564 VerifyBeforeExit || 1565 VerifyDuringStartup || 1566 VerifyAfterGC, "too expensive"); 1567 #endif 1568 assert_locked_or_safepoint(SystemDictionary_lock); 1569 1570 // First look in the loaded class array 1571 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1572 int d_index = dictionary()->hash_to_index(d_hash); 1573 return find_class(d_index, d_hash, class_name, loader_data); 1574 } 1575 1576 1577 // Get the next class in the diictionary. 1578 Klass* SystemDictionary::try_get_next_class() { 1579 return dictionary()->try_get_next_class(); 1580 } 1581 1582 1583 // ---------------------------------------------------------------------------- 1584 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1585 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1586 // before a new class is used. 1587 1588 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1589 assert(k.not_null(), "just checking"); 1590 assert_locked_or_safepoint(Compile_lock); 1591 1592 // Link into hierachy. Make sure the vtables are initialized before linking into 1593 k->append_to_sibling_list(); // add to superklass/sibling list 1594 k->process_interfaces(THREAD); // handle all "implements" declarations 1595 k->set_init_state(InstanceKlass::loaded); 1596 // Now flush all code that depended on old class hierarchy. 1597 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1598 // Also, first reinitialize vtable because it may have gotten out of synch 1599 // while the new class wasn't connected to the class hierarchy. 1600 Universe::flush_dependents_on(k); 1601 } 1602 1603 1604 // ---------------------------------------------------------------------------- 1605 // GC support 1606 1607 // Following roots during mark-sweep is separated in two phases. 1608 // 1609 // The first phase follows preloaded classes and all other system 1610 // classes, since these will never get unloaded anyway. 1611 // 1612 // The second phase removes (unloads) unreachable classes from the 1613 // system dictionary and follows the remaining classes' contents. 1614 1615 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1616 roots_oops_do(blk, NULL); 1617 } 1618 1619 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1620 // Follow all system classes and temporary placeholders in dictionary 1621 dictionary()->always_strong_classes_do(closure); 1622 1623 // Placeholders. These represent classes we're actively loading. 1624 placeholders()->classes_do(closure); 1625 } 1626 1627 // Calculate a "good" systemdictionary size based 1628 // on predicted or current loaded classes count 1629 int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1630 int newsize = _old_default_sdsize; 1631 if ((classcount > 0) && !DumpSharedSpaces) { 1632 int desiredsize = classcount/_average_depth_goal; 1633 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1634 newsize = _primelist[++_sdgeneration]) { 1635 if (desiredsize <= newsize) { 1636 break; 1637 } 1638 } 1639 } 1640 return newsize; 1641 } 1642 1643 #ifdef ASSERT 1644 class VerifySDReachableAndLiveClosure : public OopClosure { 1645 private: 1646 BoolObjectClosure* _is_alive; 1647 1648 template <class T> void do_oop_work(T* p) { 1649 oop obj = oopDesc::load_decode_heap_oop(p); 1650 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); 1651 } 1652 1653 public: 1654 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1655 1656 virtual void do_oop(oop* p) { do_oop_work(p); } 1657 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1658 }; 1659 #endif 1660 1661 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1662 // Note: anonymous classes are not in the SD. 1663 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { 1664 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1665 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive); 1666 bool unloading_occurred = false; 1667 if (has_dead_loaders) { 1668 unloading_occurred = dictionary()->do_unloading(); 1669 constraints()->purge_loader_constraints(); 1670 resolution_errors()->purge_resolution_errors(); 1671 } 1672 // Oops referenced by the system dictionary may get unreachable independently 1673 // of the class loader (eg. cached protection domain oops). So we need to 1674 // explicitly unlink them here instead of in Dictionary::do_unloading. 1675 dictionary()->unlink(is_alive); 1676 #ifdef ASSERT 1677 VerifySDReachableAndLiveClosure cl(is_alive); 1678 dictionary()->oops_do(&cl); 1679 #endif 1680 return unloading_occurred; 1681 } 1682 1683 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1684 strong->do_oop(&_java_system_loader); 1685 strong->do_oop(&_system_loader_lock_obj); 1686 1687 // Adjust dictionary 1688 dictionary()->roots_oops_do(strong, weak); 1689 1690 // Visit extra methods 1691 invoke_method_table()->oops_do(strong); 1692 } 1693 1694 void SystemDictionary::oops_do(OopClosure* f) { 1695 f->do_oop(&_java_system_loader); 1696 f->do_oop(&_system_loader_lock_obj); 1697 1698 // Adjust dictionary 1699 dictionary()->oops_do(f); 1700 1701 // Visit extra methods 1702 invoke_method_table()->oops_do(f); 1703 } 1704 1705 // Extended Class redefinition support. 1706 // If one of these classes is replaced, we need to replace it in these places. 1707 // KlassClosure::do_klass should take the address of a class but we can 1708 // change that later. 1709 void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 1710 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 1711 f->do_klass(_well_known_klasses[k]); 1712 } 1713 1714 { 1715 for (int i = 0; i < T_VOID+1; i++) { 1716 if (_box_klasses[i] != NULL) { 1717 assert(i >= T_BOOLEAN, "checking"); 1718 f->do_klass(_box_klasses[i]); 1719 } 1720 } 1721 } 1722 1723 FilteredFieldsMap::classes_do(f); 1724 } 1725 1726 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 1727 f->do_klass(_abstract_ownable_synchronizer_klass); 1728 } 1729 1730 // Just the classes from defining class loaders 1731 // Don't iterate over placeholders 1732 void SystemDictionary::classes_do(void f(Klass*)) { 1733 dictionary()->classes_do(f); 1734 } 1735 1736 // Added for initialize_itable_for_klass 1737 // Just the classes from defining class loaders 1738 // Don't iterate over placeholders 1739 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 1740 dictionary()->classes_do(f, CHECK); 1741 } 1742 1743 // All classes, and their class loaders 1744 // Don't iterate over placeholders 1745 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 1746 dictionary()->classes_do(f); 1747 } 1748 1749 void SystemDictionary::placeholders_do(void f(Symbol*)) { 1750 placeholders()->entries_do(f); 1751 } 1752 1753 void SystemDictionary::methods_do(void f(Method*)) { 1754 dictionary()->methods_do(f); 1755 invoke_method_table()->methods_do(f); 1756 } 1757 1758 // ---------------------------------------------------------------------------- 1759 // Lazily load klasses 1760 1761 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1762 // if multiple threads calling this function, only one thread will load 1763 // the class. The other threads will find the loaded version once the 1764 // class is loaded. 1765 Klass* aos = _abstract_ownable_synchronizer_klass; 1766 if (aos == NULL) { 1767 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1768 // Force a fence to prevent any read before the write completes 1769 OrderAccess::fence(); 1770 _abstract_ownable_synchronizer_klass = k; 1771 } 1772 } 1773 1774 // ---------------------------------------------------------------------------- 1775 // Initialization 1776 1777 void SystemDictionary::initialize(TRAPS) { 1778 // Allocate arrays 1779 assert(dictionary() == NULL, 1780 "SystemDictionary should only be initialized once"); 1781 _sdgeneration = 0; 1782 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 1783 _placeholders = new PlaceholderTable(_nof_buckets); 1784 _number_of_modifications = 0; 1785 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1786 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1787 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1788 1789 // Allocate private object used as system class loader lock 1790 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1791 // Initialize basic classes 1792 initialize_preloaded_classes(CHECK); 1793 } 1794 1795 // Compact table of directions on the initialization of klasses: 1796 static const short wk_init_info[] = { 1797 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1798 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1799 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1800 | (int)SystemDictionary::option ), 1801 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1802 #undef WK_KLASS_INIT_INFO 1803 0 1804 }; 1805 1806 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 1807 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1808 int info = wk_init_info[id - FIRST_WKID]; 1809 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1810 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1811 Klass** klassp = &_well_known_klasses[id]; 1812 bool must_load = (init_opt < SystemDictionary::Opt); 1813 if ((*klassp) == NULL) { 1814 if (must_load) { 1815 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class 1816 } else { 1817 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass 1818 } 1819 } 1820 return ((*klassp) != NULL); 1821 } 1822 1823 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1824 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1825 for (int id = (int)start_id; id < (int)limit_id; id++) { 1826 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1827 int info = wk_init_info[id - FIRST_WKID]; 1828 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1829 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1830 1831 initialize_wk_klass((WKID)id, opt, CHECK); 1832 } 1833 1834 // move the starting value forward to the limit: 1835 start_id = limit_id; 1836 } 1837 1838 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1839 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 1840 // Preload commonly used klasses 1841 WKID scan = FIRST_WKID; 1842 // first do Object, then String, Class 1843 if (UseSharedSpaces) { 1844 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1845 // Initialize the constant pool for the Object_class 1846 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 1847 ik->constants()->restore_unshareable_info(CHECK); 1848 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1849 } else { 1850 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1851 } 1852 1853 // Calculate offsets for String and Class classes since they are loaded and 1854 // can be used after this point. 1855 java_lang_String::compute_offsets(); 1856 java_lang_Class::compute_offsets(); 1857 1858 // Fixup mirrors for classes loaded before java.lang.Class. 1859 // These calls iterate over the objects currently in the perm gen 1860 // so calling them at this point is matters (not before when there 1861 // are fewer objects and not later after there are more objects 1862 // in the perm gen. 1863 Universe::initialize_basic_type_mirrors(CHECK); 1864 Universe::fixup_mirrors(CHECK); 1865 1866 // do a bunch more: 1867 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 1868 1869 // Preload ref klasses and set reference types 1870 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 1871 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 1872 1873 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 1874 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 1875 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 1876 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 1877 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 1878 1879 // JSR 292 classes 1880 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 1881 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 1882 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 1883 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 1884 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); 1885 1886 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 1887 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 1888 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 1889 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 1890 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 1891 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 1892 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 1893 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 1894 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 1895 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 1896 1897 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 1898 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 1899 _has_loadClassInternal = (method != NULL); 1900 } 1901 { // Compute whether we should use checkPackageAccess or NOT 1902 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 1903 _has_checkPackageAccess = (method != NULL); 1904 } 1905 } 1906 1907 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 1908 // If so, returns the basic type it holds. If not, returns T_OBJECT. 1909 BasicType SystemDictionary::box_klass_type(Klass* k) { 1910 assert(k != NULL, ""); 1911 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 1912 if (_box_klasses[i] == k) 1913 return (BasicType)i; 1914 } 1915 return T_OBJECT; 1916 } 1917 1918 // Constraints on class loaders. The details of the algorithm can be 1919 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 1920 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 1921 // that the system dictionary needs to maintain a set of contraints that 1922 // must be satisfied by all classes in the dictionary. 1923 // if defining is true, then LinkageError if already in systemDictionary 1924 // if initiating loader, then ok if InstanceKlass matches existing entry 1925 1926 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 1927 instanceKlassHandle k, 1928 Handle class_loader, bool defining, 1929 TRAPS) { 1930 const char *linkage_error = NULL; 1931 { 1932 Symbol* name = k->name(); 1933 ClassLoaderData *loader_data = class_loader_data(class_loader); 1934 1935 MutexLocker mu(SystemDictionary_lock, THREAD); 1936 1937 Klass* check = find_class(d_index, d_hash, name, loader_data); 1938 if (check != (Klass*)NULL) { 1939 // if different InstanceKlass - duplicate class definition, 1940 // else - ok, class loaded by a different thread in parallel, 1941 // we should only have found it if it was done loading and ok to use 1942 // system dictionary only holds instance classes, placeholders 1943 // also holds array classes 1944 1945 assert(check->oop_is_instance(), "noninstance in systemdictionary"); 1946 if ((defining == true) || (k() != check)) { 1947 linkage_error = "loader (instance of %s): attempted duplicate class " 1948 "definition for name: \"%s\""; 1949 } else { 1950 return; 1951 } 1952 } 1953 1954 #ifdef ASSERT 1955 Symbol* ph_check = find_placeholder(name, loader_data); 1956 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 1957 #endif 1958 1959 if (linkage_error == NULL) { 1960 if (constraints()->check_or_update(k, class_loader, name) == false) { 1961 linkage_error = "loader constraint violation: loader (instance of %s)" 1962 " previously initiated loading for a different type with name \"%s\""; 1963 } 1964 } 1965 } 1966 1967 // Throw error now if needed (cannot throw while holding 1968 // SystemDictionary_lock because of rank ordering) 1969 1970 if (linkage_error) { 1971 ResourceMark rm(THREAD); 1972 const char* class_loader_name = loader_name(class_loader()); 1973 char* type_name = k->name()->as_C_string(); 1974 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + 1975 strlen(type_name); 1976 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 1977 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); 1978 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 1979 } 1980 } 1981 1982 1983 // Update system dictionary - done after check_constraint and add_to_hierachy 1984 // have been called. 1985 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 1986 int p_index, unsigned int p_hash, 1987 instanceKlassHandle k, 1988 Handle class_loader, 1989 TRAPS) { 1990 // Compile_lock prevents systemDictionary updates during compilations 1991 assert_locked_or_safepoint(Compile_lock); 1992 Symbol* name = k->name(); 1993 ClassLoaderData *loader_data = class_loader_data(class_loader); 1994 1995 { 1996 MutexLocker mu1(SystemDictionary_lock, THREAD); 1997 1998 // See whether biased locking is enabled and if so set it for this 1999 // klass. 2000 // Note that this must be done past the last potential blocking 2001 // point / safepoint. We enable biased locking lazily using a 2002 // VM_Operation to iterate the SystemDictionary and installing the 2003 // biasable mark word into each InstanceKlass's prototype header. 2004 // To avoid race conditions where we accidentally miss enabling the 2005 // optimization for one class in the process of being added to the 2006 // dictionary, we must not safepoint after the test of 2007 // BiasedLocking::enabled(). 2008 if (UseBiasedLocking && BiasedLocking::enabled()) { 2009 // Set biased locking bit for all loaded classes; it will be 2010 // cleared if revocation occurs too often for this type 2011 // NOTE that we must only do this when the class is initally 2012 // defined, not each time it is referenced from a new class loader 2013 if (k->class_loader() == class_loader()) { 2014 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2015 } 2016 } 2017 2018 // Make a new system dictionary entry. 2019 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2020 if (sd_check == NULL) { 2021 dictionary()->add_klass(name, loader_data, k); 2022 notice_modification(); 2023 } 2024 #ifdef ASSERT 2025 sd_check = find_class(d_index, d_hash, name, loader_data); 2026 assert (sd_check != NULL, "should have entry in system dictionary"); 2027 // Note: there may be a placeholder entry: for circularity testing 2028 // or for parallel defines 2029 #endif 2030 SystemDictionary_lock->notify_all(); 2031 } 2032 } 2033 2034 2035 // Try to find a class name using the loader constraints. The 2036 // loader constraints might know about a class that isn't fully loaded 2037 // yet and these will be ignored. 2038 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2039 Symbol* class_name, Handle class_loader, TRAPS) { 2040 2041 // First see if it has been loaded directly. 2042 // Force the protection domain to be null. (This removes protection checks.) 2043 Handle no_protection_domain; 2044 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2045 no_protection_domain, CHECK_NULL); 2046 if (klass != NULL) 2047 return klass; 2048 2049 // Now look to see if it has been loaded elsewhere, and is subject to 2050 // a loader constraint that would require this loader to return the 2051 // klass that is already loaded. 2052 if (FieldType::is_array(class_name)) { 2053 // For array classes, their Klass*s are not kept in the 2054 // constraint table. The element Klass*s are. 2055 FieldArrayInfo fd; 2056 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2057 if (t != T_OBJECT) { 2058 klass = Universe::typeArrayKlassObj(t); 2059 } else { 2060 MutexLocker mu(SystemDictionary_lock, THREAD); 2061 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2062 } 2063 // If element class already loaded, allocate array klass 2064 if (klass != NULL) { 2065 klass = klass->array_klass_or_null(fd.dimension()); 2066 } 2067 } else { 2068 MutexLocker mu(SystemDictionary_lock, THREAD); 2069 // Non-array classes are easy: simply check the constraint table. 2070 klass = constraints()->find_constrained_klass(class_name, class_loader); 2071 } 2072 2073 return klass; 2074 } 2075 2076 2077 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2078 Handle class_loader1, 2079 Handle class_loader2, 2080 Thread* THREAD) { 2081 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2082 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2083 2084 Symbol* constraint_name = NULL; 2085 if (!FieldType::is_array(class_name)) { 2086 constraint_name = class_name; 2087 } else { 2088 // For array classes, their Klass*s are not kept in the 2089 // constraint table. The element classes are. 2090 FieldArrayInfo fd; 2091 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2092 // primitive types always pass 2093 if (t != T_OBJECT) { 2094 return true; 2095 } else { 2096 constraint_name = fd.object_key(); 2097 } 2098 } 2099 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2100 int d_index1 = dictionary()->hash_to_index(d_hash1); 2101 2102 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2103 int d_index2 = dictionary()->hash_to_index(d_hash2); 2104 { 2105 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2106 2107 // Better never do a GC while we're holding these oops 2108 No_Safepoint_Verifier nosafepoint; 2109 2110 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2111 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2112 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2113 klass2, class_loader2); 2114 } 2115 } 2116 2117 // Add entry to resolution error table to record the error when the first 2118 // attempt to resolve a reference to a class has failed. 2119 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, 2120 Symbol* error, Symbol* message) { 2121 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2122 int index = resolution_errors()->hash_to_index(hash); 2123 { 2124 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2125 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2126 } 2127 } 2128 2129 // Delete a resolution error for RedefineClasses for a constant pool is going away 2130 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2131 resolution_errors()->delete_entry(pool); 2132 } 2133 2134 // Lookup resolution error table. Returns error if found, otherwise NULL. 2135 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which, 2136 Symbol** message) { 2137 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2138 int index = resolution_errors()->hash_to_index(hash); 2139 { 2140 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2141 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2142 if (entry != NULL) { 2143 *message = entry->message(); 2144 return entry->error(); 2145 } else { 2146 return NULL; 2147 } 2148 } 2149 } 2150 2151 2152 // Signature constraints ensure that callers and callees agree about 2153 // the meaning of type names in their signatures. This routine is the 2154 // intake for constraints. It collects them from several places: 2155 // 2156 // * LinkResolver::resolve_method (if check_access is true) requires 2157 // that the resolving class (the caller) and the defining class of 2158 // the resolved method (the callee) agree on each type in the 2159 // method's signature. 2160 // 2161 // * LinkResolver::resolve_interface_method performs exactly the same 2162 // checks. 2163 // 2164 // * LinkResolver::resolve_field requires that the constant pool 2165 // attempting to link to a field agree with the field's defining 2166 // class about the type of the field signature. 2167 // 2168 // * klassVtable::initialize_vtable requires that, when a class 2169 // overrides a vtable entry allocated by a superclass, that the 2170 // overriding method (i.e., the callee) agree with the superclass 2171 // on each type in the method's signature. 2172 // 2173 // * klassItable::initialize_itable requires that, when a class fills 2174 // in its itables, for each non-abstract method installed in an 2175 // itable, the method (i.e., the callee) agree with the interface 2176 // on each type in the method's signature. 2177 // 2178 // All those methods have a boolean (check_access, checkconstraints) 2179 // which turns off the checks. This is used from specialized contexts 2180 // such as bootstrapping, dumping, and debugging. 2181 // 2182 // No direct constraint is placed between the class and its 2183 // supertypes. Constraints are only placed along linked relations 2184 // between callers and callees. When a method overrides or implements 2185 // an abstract method in a supertype (superclass or interface), the 2186 // constraints are placed as if the supertype were the caller to the 2187 // overriding method. (This works well, since callers to the 2188 // supertype have already established agreement between themselves and 2189 // the supertype.) As a result of all this, a class can disagree with 2190 // its supertype about the meaning of a type name, as long as that 2191 // class neither calls a relevant method of the supertype, nor is 2192 // called (perhaps via an override) from the supertype. 2193 // 2194 // 2195 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2196 // 2197 // Make sure all class components (including arrays) in the given 2198 // signature will be resolved to the same class in both loaders. 2199 // Returns the name of the type that failed a loader constraint check, or 2200 // NULL if no constraint failed. No exception except OOME is thrown. 2201 // Arrays are not added to the loader constraint table, their elements are. 2202 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2203 Handle loader1, Handle loader2, 2204 bool is_method, TRAPS) { 2205 // Nothing to do if loaders are the same. 2206 if (loader1() == loader2()) { 2207 return NULL; 2208 } 2209 2210 SignatureStream sig_strm(signature, is_method); 2211 while (!sig_strm.is_done()) { 2212 if (sig_strm.is_object()) { 2213 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2214 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2215 return sig; 2216 } 2217 } 2218 sig_strm.next(); 2219 } 2220 return NULL; 2221 } 2222 2223 2224 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2225 Symbol* signature, 2226 TRAPS) { 2227 methodHandle empty; 2228 assert(MethodHandles::is_signature_polymorphic(iid) && 2229 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2230 iid != vmIntrinsics::_invokeGeneric, 2231 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid))); 2232 2233 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2234 int index = invoke_method_table()->hash_to_index(hash); 2235 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2236 methodHandle m; 2237 if (spe == NULL || spe->method() == NULL) { 2238 spe = NULL; 2239 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2240 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2241 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier, 2242 methodHandle(), CompileThreshold, "MH", CHECK_(empty)); 2243 2244 // Now grab the lock. We might have to throw away the new method, 2245 // if a racing thread has managed to install one at the same time. 2246 { 2247 MutexLocker ml(SystemDictionary_lock, THREAD); 2248 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2249 if (spe == NULL) 2250 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2251 if (spe->method() == NULL) 2252 spe->set_method(m()); 2253 } 2254 } 2255 2256 assert(spe != NULL && spe->method() != NULL, ""); 2257 return spe->method(); 2258 } 2259 2260 // Helper for unpacking the return value from linkMethod and linkCallSite. 2261 static methodHandle unpack_method_and_appendix(Handle mname, 2262 KlassHandle accessing_klass, 2263 objArrayHandle appendix_box, 2264 Handle* appendix_result, 2265 TRAPS) { 2266 methodHandle empty; 2267 if (mname.not_null()) { 2268 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2269 if (vmtarget != NULL && vmtarget->is_method()) { 2270 Method* m = (Method*)vmtarget; 2271 oop appendix = appendix_box->obj_at(0); 2272 if (TraceMethodHandles) { 2273 #ifndef PRODUCT 2274 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2275 m->print(); 2276 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2277 tty->cr(); 2278 #endif //PRODUCT 2279 } 2280 (*appendix_result) = Handle(THREAD, appendix); 2281 // the target is stored in the cpCache and if a reference to this 2282 // MethodName is dropped we need a way to make sure the 2283 // class_loader containing this method is kept alive. 2284 // FIXME: the appendix might also preserve this dependency. 2285 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2286 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2287 return methodHandle(THREAD, m); 2288 } 2289 } 2290 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2291 return empty; 2292 } 2293 2294 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name, 2295 Symbol* signature, 2296 KlassHandle accessing_klass, 2297 Handle *appendix_result, 2298 Handle *method_type_result, 2299 TRAPS) { 2300 methodHandle empty; 2301 assert(!THREAD->is_Compiler_thread(), ""); 2302 Handle method_type = 2303 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2304 if (false) { // FIXME: Decide if the Java upcall should resolve signatures. 2305 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2306 } 2307 2308 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass(); 2309 int ref_kind = JVM_REF_invokeVirtual; 2310 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2311 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2312 assert(appendix_box->obj_at(0) == NULL, ""); 2313 2314 // This should not happen. JDK code should take care of that. 2315 if (accessing_klass.is_null() || method_type.is_null()) { 2316 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2317 } 2318 2319 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2320 JavaCallArguments args; 2321 args.push_oop(accessing_klass()->java_mirror()); 2322 args.push_int(ref_kind); 2323 args.push_oop(mh_klass()->java_mirror()); 2324 args.push_oop(name_str()); 2325 args.push_oop(method_type()); 2326 args.push_oop(appendix_box()); 2327 JavaValue result(T_OBJECT); 2328 JavaCalls::call_static(&result, 2329 SystemDictionary::MethodHandleNatives_klass(), 2330 vmSymbols::linkMethod_name(), 2331 vmSymbols::linkMethod_signature(), 2332 &args, CHECK_(empty)); 2333 Handle mname(THREAD, (oop) result.get_jobject()); 2334 (*method_type_result) = method_type; 2335 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2336 } 2337 2338 2339 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2340 // signature, as interpreted relative to the given class loader. 2341 // Because of class loader constraints, all method handle usage must be 2342 // consistent with this loader. 2343 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2344 KlassHandle accessing_klass, 2345 TRAPS) { 2346 Handle empty; 2347 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2348 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2349 int index = invoke_method_table()->hash_to_index(hash); 2350 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2351 if (spe != NULL && spe->method_type() != NULL) { 2352 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2353 return Handle(THREAD, spe->method_type()); 2354 } else if (THREAD->is_Compiler_thread()) { 2355 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2356 return Handle(); // do not attempt from within compiler, unless it was cached 2357 } 2358 2359 Handle class_loader, protection_domain; 2360 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader 2361 int npts = ArgumentCount(signature).size(); 2362 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2363 int arg = 0; 2364 Handle rt; // the return type from the signature 2365 ResourceMark rm(THREAD); 2366 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2367 oop mirror = NULL; 2368 if (is_on_bcp) { 2369 // Note: class_loader & protection_domain are both null at this point. 2370 mirror = ss.as_java_mirror(class_loader, protection_domain, 2371 SignatureStream::ReturnNull, CHECK_(empty)); 2372 if (mirror == NULL) { 2373 // fall back from BCP to accessing_klass 2374 if (accessing_klass.not_null()) { 2375 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2376 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2377 } 2378 is_on_bcp = false; 2379 } 2380 } 2381 if (!is_on_bcp) { 2382 // Resolve, throwing a real error if it doesn't work. 2383 mirror = ss.as_java_mirror(class_loader, protection_domain, 2384 SignatureStream::NCDFError, CHECK_(empty)); 2385 } 2386 if (ss.at_return_type()) 2387 rt = Handle(THREAD, mirror); 2388 else 2389 pts->obj_at_put(arg++, mirror); 2390 2391 // Check accessibility. 2392 if (ss.is_object() && accessing_klass.not_null()) { 2393 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2394 mirror = NULL; // safety 2395 // Emulate ConstantPool::verify_constant_pool_resolve. 2396 if (sel_klass->oop_is_objArray()) 2397 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2398 if (sel_klass->oop_is_instance()) { 2399 KlassHandle sel_kh(THREAD, sel_klass); 2400 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2401 } 2402 } 2403 } 2404 assert(arg == npts, ""); 2405 2406 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType 2407 JavaCallArguments args(Handle(THREAD, rt())); 2408 args.push_oop(pts()); 2409 JavaValue result(T_OBJECT); 2410 JavaCalls::call_static(&result, 2411 SystemDictionary::MethodHandleNatives_klass(), 2412 vmSymbols::findMethodHandleType_name(), 2413 vmSymbols::findMethodHandleType_signature(), 2414 &args, CHECK_(empty)); 2415 Handle method_type(THREAD, (oop) result.get_jobject()); 2416 2417 if (is_on_bcp) { 2418 // We can cache this MethodType inside the JVM. 2419 MutexLocker ml(SystemDictionary_lock, THREAD); 2420 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2421 if (spe == NULL) 2422 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2423 if (spe->method_type() == NULL) { 2424 spe->set_method_type(method_type()); 2425 } 2426 } 2427 2428 // report back to the caller with the MethodType 2429 return method_type; 2430 } 2431 2432 // Ask Java code to find or construct a method handle constant. 2433 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2434 int ref_kind, //e.g., JVM_REF_invokeVirtual 2435 KlassHandle callee, 2436 Symbol* name_sym, 2437 Symbol* signature, 2438 TRAPS) { 2439 Handle empty; 2440 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2441 Handle type; 2442 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2443 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2444 } else if (caller.is_null()) { 2445 // This should not happen. JDK code should take care of that. 2446 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2447 } else { 2448 ResourceMark rm(THREAD); 2449 SignatureStream ss(signature, false); 2450 if (!ss.is_done()) { 2451 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2452 SignatureStream::NCDFError, CHECK_(empty)); 2453 type = Handle(THREAD, mirror); 2454 ss.next(); 2455 if (!ss.is_done()) type = Handle(); // error! 2456 } 2457 } 2458 if (type.is_null()) { 2459 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2460 } 2461 2462 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2463 JavaCallArguments args; 2464 args.push_oop(caller->java_mirror()); // the referring class 2465 args.push_int(ref_kind); 2466 args.push_oop(callee->java_mirror()); // the target class 2467 args.push_oop(name()); 2468 args.push_oop(type()); 2469 JavaValue result(T_OBJECT); 2470 JavaCalls::call_static(&result, 2471 SystemDictionary::MethodHandleNatives_klass(), 2472 vmSymbols::linkMethodHandleConstant_name(), 2473 vmSymbols::linkMethodHandleConstant_signature(), 2474 &args, CHECK_(empty)); 2475 return Handle(THREAD, (oop) result.get_jobject()); 2476 } 2477 2478 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2479 // name and signature, as interpreted relative to the given class loader. 2480 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2481 Handle bootstrap_specifier, 2482 Symbol* name, 2483 Symbol* type, 2484 Handle *appendix_result, 2485 Handle *method_type_result, 2486 TRAPS) { 2487 methodHandle empty; 2488 Handle bsm, info; 2489 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2490 bsm = bootstrap_specifier; 2491 } else { 2492 assert(bootstrap_specifier->is_objArray(), ""); 2493 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2494 int len = args->length(); 2495 assert(len >= 1, ""); 2496 bsm = Handle(THREAD, args->obj_at(0)); 2497 if (len > 1) { 2498 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2499 for (int i = 1; i < len; i++) 2500 args1->obj_at_put(i-1, args->obj_at(i)); 2501 info = Handle(THREAD, args1); 2502 } 2503 } 2504 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2505 "caller must supply a valid BSM"); 2506 2507 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2508 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2509 2510 // This should not happen. JDK code should take care of that. 2511 if (caller.is_null() || method_type.is_null()) { 2512 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2513 } 2514 2515 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2516 assert(appendix_box->obj_at(0) == NULL, ""); 2517 2518 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2519 JavaCallArguments args; 2520 args.push_oop(caller->java_mirror()); 2521 args.push_oop(bsm()); 2522 args.push_oop(method_name()); 2523 args.push_oop(method_type()); 2524 args.push_oop(info()); 2525 args.push_oop(appendix_box); 2526 JavaValue result(T_OBJECT); 2527 JavaCalls::call_static(&result, 2528 SystemDictionary::MethodHandleNatives_klass(), 2529 vmSymbols::linkCallSite_name(), 2530 vmSymbols::linkCallSite_signature(), 2531 &args, CHECK_(empty)); 2532 Handle mname(THREAD, (oop) result.get_jobject()); 2533 (*method_type_result) = method_type; 2534 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2535 } 2536 2537 // Since the identity hash code for symbols changes when the symbols are 2538 // moved from the regular perm gen (hash in the mark word) to the shared 2539 // spaces (hash is the address), the classes loaded into the dictionary 2540 // may be in the wrong buckets. 2541 2542 void SystemDictionary::reorder_dictionary() { 2543 dictionary()->reorder_dictionary(); 2544 } 2545 2546 2547 void SystemDictionary::copy_buckets(char** top, char* end) { 2548 dictionary()->copy_buckets(top, end); 2549 } 2550 2551 2552 void SystemDictionary::copy_table(char** top, char* end) { 2553 dictionary()->copy_table(top, end); 2554 } 2555 2556 2557 void SystemDictionary::reverse() { 2558 dictionary()->reverse(); 2559 } 2560 2561 int SystemDictionary::number_of_classes() { 2562 return dictionary()->number_of_entries(); 2563 } 2564 2565 2566 // ---------------------------------------------------------------------------- 2567 #ifndef PRODUCT 2568 2569 void SystemDictionary::print() { 2570 dictionary()->print(); 2571 2572 // Placeholders 2573 GCMutexLocker mu(SystemDictionary_lock); 2574 placeholders()->print(); 2575 2576 // loader constraints - print under SD_lock 2577 constraints()->print(); 2578 } 2579 2580 #endif 2581 2582 void SystemDictionary::verify() { 2583 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2584 guarantee(constraints() != NULL, 2585 "Verify of loader constraints failed"); 2586 guarantee(dictionary()->number_of_entries() >= 0 && 2587 placeholders()->number_of_entries() >= 0, 2588 "Verify of system dictionary failed"); 2589 2590 // Verify dictionary 2591 dictionary()->verify(); 2592 2593 GCMutexLocker mu(SystemDictionary_lock); 2594 placeholders()->verify(); 2595 2596 // Verify constraint table 2597 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2598 constraints()->verify(dictionary(), placeholders()); 2599 } 2600 2601 // utility function for class load event 2602 void SystemDictionary::post_class_load_event(const Ticks& start_time, 2603 instanceKlassHandle k, 2604 Handle initiating_loader) { 2605 #if INCLUDE_TRACE 2606 EventClassLoad event(UNTIMED); 2607 if (event.should_commit()) { 2608 event.set_starttime(start_time); 2609 event.set_loadedClass(k()); 2610 oop defining_class_loader = k->class_loader(); 2611 event.set_definingClassLoader(defining_class_loader != NULL ? 2612 defining_class_loader->klass() : (Klass*)NULL); 2613 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader(); 2614 event.set_initiatingClassLoader(class_loader != NULL ? 2615 class_loader->klass() : (Klass*)NULL); 2616 event.commit(); 2617 } 2618 #endif /* INCLUDE_TRACE */ 2619 } 2620 2621 #ifndef PRODUCT 2622 2623 // statistics code 2624 class ClassStatistics: AllStatic { 2625 private: 2626 static int nclasses; // number of classes 2627 static int nmethods; // number of methods 2628 static int nmethoddata; // number of methodData 2629 static int class_size; // size of class objects in words 2630 static int method_size; // size of method objects in words 2631 static int debug_size; // size of debug info in methods 2632 static int methoddata_size; // size of methodData objects in words 2633 2634 static void do_class(Klass* k) { 2635 nclasses++; 2636 class_size += k->size(); 2637 if (k->oop_is_instance()) { 2638 InstanceKlass* ik = (InstanceKlass*)k; 2639 class_size += ik->methods()->size(); 2640 class_size += ik->constants()->size(); 2641 class_size += ik->local_interfaces()->size(); 2642 class_size += ik->transitive_interfaces()->size(); 2643 // We do not have to count implementors, since we only store one! 2644 // SSS: How should these be accounted now that they have moved? 2645 // class_size += ik->fields()->length(); 2646 } 2647 } 2648 2649 static void do_method(Method* m) { 2650 nmethods++; 2651 method_size += m->size(); 2652 // class loader uses same objArray for empty vectors, so don't count these 2653 if (m->has_stackmap_table()) { 2654 method_size += m->stackmap_data()->size(); 2655 } 2656 2657 MethodData* mdo = m->method_data(); 2658 if (mdo != NULL) { 2659 nmethoddata++; 2660 methoddata_size += mdo->size(); 2661 } 2662 } 2663 2664 public: 2665 static void print() { 2666 SystemDictionary::classes_do(do_class); 2667 SystemDictionary::methods_do(do_method); 2668 tty->print_cr("Class statistics:"); 2669 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); 2670 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, 2671 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); 2672 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); 2673 } 2674 }; 2675 2676 2677 int ClassStatistics::nclasses = 0; 2678 int ClassStatistics::nmethods = 0; 2679 int ClassStatistics::nmethoddata = 0; 2680 int ClassStatistics::class_size = 0; 2681 int ClassStatistics::method_size = 0; 2682 int ClassStatistics::debug_size = 0; 2683 int ClassStatistics::methoddata_size = 0; 2684 2685 void SystemDictionary::print_class_statistics() { 2686 ResourceMark rm; 2687 ClassStatistics::print(); 2688 } 2689 2690 2691 class MethodStatistics: AllStatic { 2692 public: 2693 enum { 2694 max_parameter_size = 10 2695 }; 2696 private: 2697 2698 static int _number_of_methods; 2699 static int _number_of_final_methods; 2700 static int _number_of_static_methods; 2701 static int _number_of_native_methods; 2702 static int _number_of_synchronized_methods; 2703 static int _number_of_profiled_methods; 2704 static int _number_of_bytecodes; 2705 static int _parameter_size_profile[max_parameter_size]; 2706 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; 2707 2708 static void initialize() { 2709 _number_of_methods = 0; 2710 _number_of_final_methods = 0; 2711 _number_of_static_methods = 0; 2712 _number_of_native_methods = 0; 2713 _number_of_synchronized_methods = 0; 2714 _number_of_profiled_methods = 0; 2715 _number_of_bytecodes = 0; 2716 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; 2717 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; 2718 }; 2719 2720 static void do_method(Method* m) { 2721 _number_of_methods++; 2722 // collect flag info 2723 if (m->is_final() ) _number_of_final_methods++; 2724 if (m->is_static() ) _number_of_static_methods++; 2725 if (m->is_native() ) _number_of_native_methods++; 2726 if (m->is_synchronized()) _number_of_synchronized_methods++; 2727 if (m->method_data() != NULL) _number_of_profiled_methods++; 2728 // collect parameter size info (add one for receiver, if any) 2729 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; 2730 // collect bytecodes info 2731 { 2732 Thread *thread = Thread::current(); 2733 HandleMark hm(thread); 2734 BytecodeStream s(methodHandle(thread, m)); 2735 Bytecodes::Code c; 2736 while ((c = s.next()) >= 0) { 2737 _number_of_bytecodes++; 2738 _bytecodes_profile[c]++; 2739 } 2740 } 2741 } 2742 2743 public: 2744 static void print() { 2745 initialize(); 2746 SystemDictionary::methods_do(do_method); 2747 // generate output 2748 tty->cr(); 2749 tty->print_cr("Method statistics (static):"); 2750 // flag distribution 2751 tty->cr(); 2752 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); 2753 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); 2754 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); 2755 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); 2756 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); 2757 // parameter size profile 2758 tty->cr(); 2759 { int tot = 0; 2760 int avg = 0; 2761 for (int i = 0; i < max_parameter_size; i++) { 2762 int n = _parameter_size_profile[i]; 2763 tot += n; 2764 avg += n*i; 2765 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); 2766 } 2767 assert(tot == _number_of_methods, "should be the same"); 2768 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); 2769 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); 2770 } 2771 // bytecodes profile 2772 tty->cr(); 2773 { int tot = 0; 2774 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { 2775 if (Bytecodes::is_defined(i)) { 2776 Bytecodes::Code c = Bytecodes::cast(i); 2777 int n = _bytecodes_profile[c]; 2778 tot += n; 2779 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); 2780 } 2781 } 2782 assert(tot == _number_of_bytecodes, "should be the same"); 2783 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); 2784 } 2785 tty->cr(); 2786 } 2787 }; 2788 2789 int MethodStatistics::_number_of_methods; 2790 int MethodStatistics::_number_of_final_methods; 2791 int MethodStatistics::_number_of_static_methods; 2792 int MethodStatistics::_number_of_native_methods; 2793 int MethodStatistics::_number_of_synchronized_methods; 2794 int MethodStatistics::_number_of_profiled_methods; 2795 int MethodStatistics::_number_of_bytecodes; 2796 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; 2797 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; 2798 2799 2800 void SystemDictionary::print_method_statistics() { 2801 MethodStatistics::print(); 2802 } 2803 2804 #endif // PRODUCT