1 /* 2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/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/systemDictionary.hpp" 33 #if INCLUDE_CDS 34 #include "classfile/sharedClassUtil.hpp" 35 #include "classfile/systemDictionaryShared.hpp" 36 #endif 37 #include "classfile/vmSymbols.hpp" 38 #include "compiler/compileBroker.hpp" 39 #include "interpreter/bytecodeStream.hpp" 40 #include "interpreter/interpreter.hpp" 41 #include "memory/filemap.hpp" 42 #include "memory/gcLocker.hpp" 43 #include "memory/oopFactory.hpp" 44 #include "oops/instanceKlass.hpp" 45 #include "oops/instanceRefKlass.hpp" 46 #include "oops/klass.inline.hpp" 47 #include "oops/methodData.hpp" 48 #include "oops/objArrayKlass.hpp" 49 #include "oops/oop.inline.hpp" 50 #include "oops/oop.inline2.hpp" 51 #include "oops/typeArrayKlass.hpp" 52 #include "prims/jvmtiEnvBase.hpp" 53 #include "prims/methodHandles.hpp" 54 #include "runtime/arguments.hpp" 55 #include "runtime/biasedLocking.hpp" 56 #include "runtime/fieldType.hpp" 57 #include "runtime/handles.inline.hpp" 58 #include "runtime/java.hpp" 59 #include "runtime/javaCalls.hpp" 60 #include "runtime/mutexLocker.hpp" 61 #include "runtime/orderAccess.inline.hpp" 62 #include "runtime/signature.hpp" 63 #include "services/classLoadingService.hpp" 64 #include "services/threadService.hpp" 65 #include "utilities/macros.hpp" 66 #include "utilities/ticks.hpp" 67 #if INCLUDE_TRACE 68 #include "trace/tracing.hpp" 69 #endif 70 71 Dictionary* SystemDictionary::_dictionary = NULL; 72 PlaceholderTable* SystemDictionary::_placeholders = NULL; 73 Dictionary* SystemDictionary::_shared_dictionary = NULL; 74 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 75 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 76 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 77 78 79 int SystemDictionary::_number_of_modifications = 0; 80 int SystemDictionary::_sdgeneration = 0; 81 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 82 20201,40423,99991}; 83 84 oop SystemDictionary::_system_loader_lock_obj = NULL; 85 86 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 87 = { NULL /*, NULL...*/ }; 88 89 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 90 91 oop SystemDictionary::_java_system_loader = NULL; 92 93 bool SystemDictionary::_has_loadClassInternal = false; 94 bool SystemDictionary::_has_checkPackageAccess = false; 95 96 // lazily initialized klass variables 97 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 98 99 100 // ---------------------------------------------------------------------------- 101 // Java-level SystemLoader 102 103 oop SystemDictionary::java_system_loader() { 104 return _java_system_loader; 105 } 106 107 void SystemDictionary::compute_java_system_loader(TRAPS) { 108 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 109 JavaValue result(T_OBJECT); 110 JavaCalls::call_static(&result, 111 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 112 vmSymbols::getSystemClassLoader_name(), 113 vmSymbols::void_classloader_signature(), 114 CHECK); 115 116 _java_system_loader = (oop)result.get_jobject(); 117 118 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) 119 } 120 121 122 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 123 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 124 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL); 125 } 126 127 // ---------------------------------------------------------------------------- 128 // debugging 129 130 #ifdef ASSERT 131 132 // return true if class_name contains no '.' (internal format is '/') 133 bool SystemDictionary::is_internal_format(Symbol* class_name) { 134 if (class_name != NULL) { 135 ResourceMark rm; 136 char* name = class_name->as_C_string(); 137 return strchr(name, '.') == NULL; 138 } else { 139 return true; 140 } 141 } 142 143 #endif 144 145 // ---------------------------------------------------------------------------- 146 // Parallel class loading check 147 148 bool SystemDictionary::is_parallelCapable(Handle class_loader) { 149 if (UnsyncloadClass || class_loader.is_null()) return true; 150 if (AlwaysLockClassLoader) return false; 151 return java_lang_ClassLoader::parallelCapable(class_loader()); 152 } 153 // ---------------------------------------------------------------------------- 154 // ParallelDefineClass flag does not apply to bootclass loader 155 bool SystemDictionary::is_parallelDefine(Handle class_loader) { 156 if (class_loader.is_null()) return false; 157 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 158 return true; 159 } 160 return false; 161 } 162 163 /** 164 * Returns true if the passed class loader is the extension class loader. 165 */ 166 bool SystemDictionary::is_ext_class_loader(Handle class_loader) { 167 if (class_loader.is_null()) { 168 return false; 169 } 170 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader()); 171 } 172 173 // ---------------------------------------------------------------------------- 174 // Resolving of classes 175 176 // Forwards to resolve_or_null 177 178 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 179 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 180 if (HAS_PENDING_EXCEPTION || klass == NULL) { 181 KlassHandle k_h(THREAD, klass); 182 // can return a null klass 183 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); 184 } 185 return klass; 186 } 187 188 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) { 189 if (HAS_PENDING_EXCEPTION) { 190 // If we have a pending exception we forward it to the caller, unless throw_error is true, 191 // in which case we have to check whether the pending exception is a ClassNotFoundException, 192 // and if so convert it to a NoClassDefFoundError 193 // And chain the original ClassNotFoundException 194 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 195 ResourceMark rm(THREAD); 196 assert(klass_h() == NULL, "Should not have result with exception pending"); 197 Handle e(THREAD, PENDING_EXCEPTION); 198 CLEAR_PENDING_EXCEPTION; 199 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 200 } else { 201 return NULL; 202 } 203 } 204 // Class not found, throw appropriate error or exception depending on value of throw_error 205 if (klass_h() == NULL) { 206 ResourceMark rm(THREAD); 207 if (throw_error) { 208 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 209 } else { 210 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 211 } 212 } 213 return (Klass*)klass_h(); 214 } 215 216 217 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 218 bool throw_error, TRAPS) 219 { 220 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 221 } 222 223 224 // Forwards to resolve_instance_class_or_null 225 226 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 227 assert(!THREAD->is_Compiler_thread(), 228 err_msg("can not load classes with compiler thread: class=%s, classloader=%s", 229 class_name->as_C_string(), 230 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string())); 231 if (FieldType::is_array(class_name)) { 232 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 233 } else if (FieldType::is_obj(class_name)) { 234 ResourceMark rm(THREAD); 235 // Ignore wrapping L and ;. 236 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 237 class_name->utf8_length() - 2, CHECK_NULL); 238 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL); 239 } else { 240 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 241 } 242 } 243 244 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 245 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 246 } 247 248 // Forwards to resolve_instance_class_or_null 249 250 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 251 Handle class_loader, 252 Handle protection_domain, 253 TRAPS) { 254 assert(FieldType::is_array(class_name), "must be array"); 255 Klass* k = NULL; 256 FieldArrayInfo fd; 257 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 258 // of this call 259 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 260 if (t == T_OBJECT) { 261 // naked oop "k" is OK here -- we assign back into it 262 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 263 class_loader, 264 protection_domain, 265 CHECK_NULL); 266 if (k != NULL) { 267 k = k->array_klass(fd.dimension(), CHECK_NULL); 268 } 269 } else { 270 k = Universe::typeArrayKlassObj(t); 271 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 272 } 273 return k; 274 } 275 276 277 // Must be called for any super-class or super-interface resolution 278 // during class definition to allow class circularity checking 279 // super-interface callers: 280 // parse_interfaces - for defineClass & jvmtiRedefineClasses 281 // super-class callers: 282 // ClassFileParser - for defineClass & jvmtiRedefineClasses 283 // load_shared_class - while loading a class from shared archive 284 // resolve_instance_class_or_null: 285 // via: handle_parallel_super_load 286 // when resolving a class that has an existing placeholder with 287 // a saved superclass [i.e. a defineClass is currently in progress] 288 // if another thread is trying to resolve the class, it must do 289 // super-class checks on its own thread to catch class circularity 290 // This last call is critical in class circularity checking for cases 291 // where classloading is delegated to different threads and the 292 // classloader lock is released. 293 // Take the case: Base->Super->Base 294 // 1. If thread T1 tries to do a defineClass of class Base 295 // resolve_super_or_fail creates placeholder: T1, Base (super Super) 296 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super 297 // so it tries to load Super 298 // 3. If we load the class internally, or user classloader uses same thread 299 // loadClassFromxxx or defineClass via parseClassFile Super ... 300 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 301 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 302 // 3.4 calls resolve_super_or_fail Base 303 // 3.5 finds T1,Base -> throws class circularity 304 //OR 4. If T2 tries to resolve Super via defineClass Super ... 305 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 306 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 307 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 308 // 4.4 finds T2, Super -> throws class circularity 309 // Must be called, even if superclass is null, since this is 310 // where the placeholder entry is created which claims this 311 // thread is loading this class/classloader. 312 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 313 Symbol* class_name, 314 Handle class_loader, 315 Handle protection_domain, 316 bool is_superclass, 317 TRAPS) { 318 // Double-check, if child class is already loaded, just return super-class,interface 319 // Don't add a placedholder if already loaded, i.e. already in system dictionary 320 // Make sure there's a placeholder for the *child* before resolving. 321 // Used as a claim that this thread is currently loading superclass/classloader 322 // Used here for ClassCircularity checks and also for heap verification 323 // (every InstanceKlass in the heap needs to be in the system dictionary 324 // or have a placeholder). 325 // Must check ClassCircularity before checking if super class is already loaded 326 // 327 // We might not already have a placeholder if this child_name was 328 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 329 // the name of the class might not be known until the stream is actually 330 // parsed. 331 // Bugs 4643874, 4715493 332 // compute_hash can have a safepoint 333 334 ClassLoaderData* loader_data = class_loader_data(class_loader); 335 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 336 int d_index = dictionary()->hash_to_index(d_hash); 337 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 338 int p_index = placeholders()->hash_to_index(p_hash); 339 // can't throw error holding a lock 340 bool child_already_loaded = false; 341 bool throw_circularity_error = false; 342 { 343 MutexLocker mu(SystemDictionary_lock, THREAD); 344 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 345 Klass* quicksuperk; 346 // to support // loading: if child done loading, just return superclass 347 // if class_name, & class_loader don't match: 348 // if initial define, SD update will give LinkageError 349 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 350 // so we don't throw an exception here. 351 // see: nsk redefclass014 & java.lang.instrument Instrument032 352 if ((childk != NULL ) && (is_superclass) && 353 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) && 354 355 ((quicksuperk->name() == class_name) && 356 (quicksuperk->class_loader() == class_loader()))) { 357 return quicksuperk; 358 } else { 359 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 360 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 361 throw_circularity_error = true; 362 } 363 } 364 if (!throw_circularity_error) { 365 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 366 } 367 } 368 if (throw_circularity_error) { 369 ResourceMark rm(THREAD); 370 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 371 } 372 373 // java.lang.Object should have been found above 374 assert(class_name != NULL, "null super class for resolving"); 375 // Resolve the super class or interface, check results on return 376 Klass* superk = SystemDictionary::resolve_or_null(class_name, 377 class_loader, 378 protection_domain, 379 THREAD); 380 381 KlassHandle superk_h(THREAD, superk); 382 383 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 384 // It is no longer necessary to keep the placeholder table alive until update_dictionary 385 // or error. GC used to walk the placeholder table as strong roots. 386 // The instanceKlass is kept alive because the class loader is on the stack, 387 // which keeps the loader_data alive, as well as all instanceKlasses in 388 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 389 { 390 MutexLocker mu(SystemDictionary_lock, THREAD); 391 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 392 SystemDictionary_lock->notify_all(); 393 } 394 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 395 // can null superk 396 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); 397 } 398 399 return superk_h(); 400 } 401 402 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 403 Handle class_loader, 404 Handle protection_domain, 405 TRAPS) { 406 if(!has_checkPackageAccess()) return; 407 408 // Now we have to call back to java to check if the initating class has access 409 JavaValue result(T_VOID); 410 if (TraceProtectionDomainVerification) { 411 // Print out trace information 412 tty->print_cr("Checking package access"); 413 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); 414 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); 415 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); 416 } 417 418 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 419 JavaCalls::call_special(&result, 420 class_loader, 421 system_loader, 422 vmSymbols::checkPackageAccess_name(), 423 vmSymbols::class_protectiondomain_signature(), 424 Handle(THREAD, klass->java_mirror()), 425 protection_domain, 426 THREAD); 427 428 if (TraceProtectionDomainVerification) { 429 if (HAS_PENDING_EXCEPTION) { 430 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); 431 } else { 432 tty->print_cr(" -> granted"); 433 } 434 tty->cr(); 435 } 436 437 if (HAS_PENDING_EXCEPTION) return; 438 439 // If no exception has been thrown, we have validated the protection domain 440 // Insert the protection domain of the initiating class into the set. 441 { 442 // We recalculate the entry here -- we've called out to java since 443 // the last time it was calculated. 444 ClassLoaderData* loader_data = class_loader_data(class_loader); 445 446 Symbol* kn = klass->name(); 447 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 448 int d_index = dictionary()->hash_to_index(d_hash); 449 450 MutexLocker mu(SystemDictionary_lock, THREAD); 451 { 452 // Note that we have an entry, and entries can be deleted only during GC, 453 // so we cannot allow GC to occur while we're holding this entry. 454 455 // We're using a No_Safepoint_Verifier to catch any place where we 456 // might potentially do a GC at all. 457 // Dictionary::do_unloading() asserts that classes in SD are only 458 // unloaded at a safepoint. Anonymous classes are not in SD. 459 No_Safepoint_Verifier nosafepoint; 460 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 461 protection_domain, THREAD); 462 } 463 } 464 } 465 466 // We only get here if this thread finds that another thread 467 // has already claimed the placeholder token for the current operation, 468 // but that other thread either never owned or gave up the 469 // object lock 470 // Waits on SystemDictionary_lock to indicate placeholder table updated 471 // On return, caller must recheck placeholder table state 472 // 473 // We only get here if 474 // 1) custom classLoader, i.e. not bootstrap classloader 475 // 2) UnsyncloadClass not set 476 // 3) custom classLoader has broken the class loader objectLock 477 // so another thread got here in parallel 478 // 479 // lockObject must be held. 480 // Complicated dance due to lock ordering: 481 // Must first release the classloader object lock to 482 // allow initial definer to complete the class definition 483 // and to avoid deadlock 484 // Reclaim classloader lock object with same original recursion count 485 // Must release SystemDictionary_lock after notify, since 486 // class loader lock must be claimed before SystemDictionary_lock 487 // to prevent deadlocks 488 // 489 // The notify allows applications that did an untimed wait() on 490 // the classloader object lock to not hang. 491 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 492 assert_lock_strong(SystemDictionary_lock); 493 494 bool calledholdinglock 495 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 496 assert(calledholdinglock,"must hold lock for notify"); 497 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 498 ObjectSynchronizer::notifyall(lockObject, THREAD); 499 intptr_t saved_recursions, saved_trace_exit_stack; 500 ObjectSynchronizer::complete_exit(lockObject, &saved_recursions, &saved_trace_exit_stack, THREAD); 501 SystemDictionary_lock->wait(); 502 SystemDictionary_lock->unlock(); 503 ObjectSynchronizer::reenter(lockObject, saved_recursions, saved_trace_exit_stack, THREAD); 504 SystemDictionary_lock->lock(); 505 } 506 507 // If the class in is in the placeholder table, class loading is in progress 508 // For cases where the application changes threads to load classes, it 509 // is critical to ClassCircularity detection that we try loading 510 // the superclass on the same thread internally, so we do parallel 511 // super class loading here. 512 // This also is critical in cases where the original thread gets stalled 513 // even in non-circularity situations. 514 // Note: must call resolve_super_or_fail even if null super - 515 // to force placeholder entry creation for this class for circularity detection 516 // Caller must check for pending exception 517 // Returns non-null Klass* if other thread has completed load 518 // and we are done, 519 // If return null Klass* and no pending exception, the caller must load the class 520 instanceKlassHandle SystemDictionary::handle_parallel_super_load( 521 Symbol* name, Symbol* superclassname, Handle class_loader, 522 Handle protection_domain, Handle lockObject, TRAPS) { 523 524 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 525 ClassLoaderData* loader_data = class_loader_data(class_loader); 526 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 527 int d_index = dictionary()->hash_to_index(d_hash); 528 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 529 int p_index = placeholders()->hash_to_index(p_hash); 530 531 // superk is not used, resolve_super called for circularity check only 532 // This code is reached in two situations. One if this thread 533 // is loading the same class twice (e.g. ClassCircularity, or 534 // java.lang.instrument). 535 // The second is if another thread started the resolve_super first 536 // and has not yet finished. 537 // In both cases the original caller will clean up the placeholder 538 // entry on error. 539 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 540 superclassname, 541 class_loader, 542 protection_domain, 543 true, 544 CHECK_(nh)); 545 546 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 547 // Serial class loaders and bootstrap classloader do wait for superclass loads 548 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 549 MutexLocker mu(SystemDictionary_lock, THREAD); 550 // Check if classloading completed while we were loading superclass or waiting 551 Klass* check = find_class(d_index, d_hash, name, loader_data); 552 if (check != NULL) { 553 // Klass is already loaded, so just return it 554 return(instanceKlassHandle(THREAD, check)); 555 } else { 556 return nh; 557 } 558 } 559 560 // must loop to both handle other placeholder updates 561 // and spurious notifications 562 bool super_load_in_progress = true; 563 PlaceholderEntry* placeholder; 564 while (super_load_in_progress) { 565 MutexLocker mu(SystemDictionary_lock, THREAD); 566 // Check if classloading completed while we were loading superclass or waiting 567 Klass* check = find_class(d_index, d_hash, name, loader_data); 568 if (check != NULL) { 569 // Klass is already loaded, so just return it 570 return(instanceKlassHandle(THREAD, check)); 571 } else { 572 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 573 if (placeholder && placeholder->super_load_in_progress() ){ 574 // Before UnsyncloadClass: 575 // We only get here if the application has released the 576 // classloader lock when another thread was in the middle of loading a 577 // superclass/superinterface for this class, and now 578 // this thread is also trying to load this class. 579 // To minimize surprises, the first thread that started to 580 // load a class should be the one to complete the loading 581 // with the classfile it initially expected. 582 // This logic has the current thread wait once it has done 583 // all the superclass/superinterface loading it can, until 584 // the original thread completes the class loading or fails 585 // If it completes we will use the resulting InstanceKlass 586 // which we will find below in the systemDictionary. 587 // We also get here for parallel bootstrap classloader 588 if (class_loader.is_null()) { 589 SystemDictionary_lock->wait(); 590 } else { 591 double_lock_wait(lockObject, THREAD); 592 } 593 } else { 594 // If not in SD and not in PH, other thread's load must have failed 595 super_load_in_progress = false; 596 } 597 } 598 } 599 return (nh); 600 } 601 602 603 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 604 Handle class_loader, 605 Handle protection_domain, 606 TRAPS) { 607 assert(name != NULL && !FieldType::is_array(name) && 608 !FieldType::is_obj(name), "invalid class name"); 609 610 Ticks class_load_start_time = Ticks::now(); 611 612 // UseNewReflection 613 // Fix for 4474172; see evaluation for more details 614 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 615 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 616 617 // Do lookup to see if class already exist and the protection domain 618 // has the right access 619 // This call uses find which checks protection domain already matches 620 // All subsequent calls use find_class, and set has_loaded_class so that 621 // before we return a result we call out to java to check for valid protection domain 622 // to allow returning the Klass* and add it to the pd_set if it is valid 623 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 624 int d_index = dictionary()->hash_to_index(d_hash); 625 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 626 protection_domain, THREAD); 627 if (probe != NULL) return probe; 628 629 630 // Non-bootstrap class loaders will call out to class loader and 631 // define via jvm/jni_DefineClass which will acquire the 632 // class loader object lock to protect against multiple threads 633 // defining the class in parallel by accident. 634 // This lock must be acquired here so the waiter will find 635 // any successful result in the SystemDictionary and not attempt 636 // the define 637 // ParallelCapable Classloaders and the bootstrap classloader, 638 // or all classloaders with UnsyncloadClass do not acquire lock here 639 bool DoObjectLock = true; 640 if (is_parallelCapable(class_loader)) { 641 DoObjectLock = false; 642 } 643 644 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 645 int p_index = placeholders()->hash_to_index(p_hash); 646 647 // Class is not in SystemDictionary so we have to do loading. 648 // Make sure we are synchronized on the class loader before we proceed 649 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 650 check_loader_lock_contention(lockObject, THREAD); 651 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 652 653 // Check again (after locking) if class already exist in SystemDictionary 654 bool class_has_been_loaded = false; 655 bool super_load_in_progress = false; 656 bool havesupername = false; 657 instanceKlassHandle k; 658 PlaceholderEntry* placeholder; 659 Symbol* superclassname = NULL; 660 661 { 662 MutexLocker mu(SystemDictionary_lock, THREAD); 663 Klass* check = find_class(d_index, d_hash, name, loader_data); 664 if (check != NULL) { 665 // Klass is already loaded, so just return it 666 class_has_been_loaded = true; 667 k = instanceKlassHandle(THREAD, check); 668 } else { 669 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 670 if (placeholder && placeholder->super_load_in_progress()) { 671 super_load_in_progress = true; 672 if (placeholder->havesupername() == true) { 673 superclassname = placeholder->supername(); 674 havesupername = true; 675 } 676 } 677 } 678 } 679 680 // If the class is in the placeholder table, class loading is in progress 681 if (super_load_in_progress && havesupername==true) { 682 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 683 class_loader, protection_domain, lockObject, THREAD); 684 if (HAS_PENDING_EXCEPTION) { 685 return NULL; 686 } 687 if (!k.is_null()) { 688 class_has_been_loaded = true; 689 } 690 } 691 692 bool throw_circularity_error = false; 693 if (!class_has_been_loaded) { 694 bool load_instance_added = false; 695 696 // add placeholder entry to record loading instance class 697 // Five cases: 698 // All cases need to prevent modifying bootclasssearchpath 699 // in parallel with a classload of same classname 700 // Redefineclasses uses existence of the placeholder for the duration 701 // of the class load to prevent concurrent redefinition of not completely 702 // defined classes. 703 // case 1. traditional classloaders that rely on the classloader object lock 704 // - no other need for LOAD_INSTANCE 705 // case 2. traditional classloaders that break the classloader object lock 706 // as a deadlock workaround. Detection of this case requires that 707 // this check is done while holding the classloader object lock, 708 // and that lock is still held when calling classloader's loadClass. 709 // For these classloaders, we ensure that the first requestor 710 // completes the load and other requestors wait for completion. 711 // case 3. UnsyncloadClass - don't use objectLocker 712 // With this flag, we allow parallel classloading of a 713 // class/classloader pair 714 // case4. Bootstrap classloader - don't own objectLocker 715 // This classloader supports parallelism at the classloader level, 716 // but only allows a single load of a class/classloader pair. 717 // No performance benefit and no deadlock issues. 718 // case 5. parallelCapable user level classloaders - without objectLocker 719 // Allow parallel classloading of a class/classloader pair 720 721 { 722 MutexLocker mu(SystemDictionary_lock, THREAD); 723 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 724 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 725 if (oldprobe) { 726 // only need check_seen_thread once, not on each loop 727 // 6341374 java/lang/Instrument with -Xcomp 728 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 729 throw_circularity_error = true; 730 } else { 731 // case 1: traditional: should never see load_in_progress. 732 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 733 734 // case 4: bootstrap classloader: prevent futile classloading, 735 // wait on first requestor 736 if (class_loader.is_null()) { 737 SystemDictionary_lock->wait(); 738 } else { 739 // case 2: traditional with broken classloader lock. wait on first 740 // requestor. 741 double_lock_wait(lockObject, THREAD); 742 } 743 // Check if classloading completed while we were waiting 744 Klass* check = find_class(d_index, d_hash, name, loader_data); 745 if (check != NULL) { 746 // Klass is already loaded, so just return it 747 k = instanceKlassHandle(THREAD, check); 748 class_has_been_loaded = true; 749 } 750 // check if other thread failed to load and cleaned up 751 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 752 } 753 } 754 } 755 } 756 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 757 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 758 // LOAD_INSTANCE in parallel 759 760 if (!throw_circularity_error && !class_has_been_loaded) { 761 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 762 load_instance_added = true; 763 // For class loaders that do not acquire the classloader object lock, 764 // if they did not catch another thread holding LOAD_INSTANCE, 765 // need a check analogous to the acquire ObjectLocker/find_class 766 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 767 // one final check if the load has already completed 768 // class loaders holding the ObjectLock shouldn't find the class here 769 Klass* check = find_class(d_index, d_hash, name, loader_data); 770 if (check != NULL) { 771 // Klass is already loaded, so return it after checking/adding protection domain 772 k = instanceKlassHandle(THREAD, check); 773 class_has_been_loaded = true; 774 } 775 } 776 } 777 778 // must throw error outside of owning lock 779 if (throw_circularity_error) { 780 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 781 ResourceMark rm(THREAD); 782 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 783 } 784 785 if (!class_has_been_loaded) { 786 787 // Do actual loading 788 k = load_instance_class(name, class_loader, THREAD); 789 790 // For UnsyncloadClass only 791 // If they got a linkageError, check if a parallel class load succeeded. 792 // If it did, then for bytecode resolution the specification requires 793 // that we return the same result we did for the other thread, i.e. the 794 // successfully loaded InstanceKlass 795 // Should not get here for classloaders that support parallelism 796 // with the new cleaner mechanism, even with AllowParallelDefineClass 797 // Bootstrap goes through here to allow for an extra guarantee check 798 if (UnsyncloadClass || (class_loader.is_null())) { 799 if (k.is_null() && HAS_PENDING_EXCEPTION 800 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 801 MutexLocker mu(SystemDictionary_lock, THREAD); 802 Klass* check = find_class(d_index, d_hash, name, loader_data); 803 if (check != NULL) { 804 // Klass is already loaded, so just use it 805 k = instanceKlassHandle(THREAD, check); 806 CLEAR_PENDING_EXCEPTION; 807 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 808 } 809 } 810 } 811 812 // If everything was OK (no exceptions, no null return value), and 813 // class_loader is NOT the defining loader, do a little more bookkeeping. 814 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 815 k->class_loader() != class_loader()) { 816 817 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 818 819 // Need to check for a PENDING_EXCEPTION again; check_constraints 820 // can throw and doesn't use the CHECK macro. 821 if (!HAS_PENDING_EXCEPTION) { 822 { // Grabbing the Compile_lock prevents systemDictionary updates 823 // during compilations. 824 MutexLocker mu(Compile_lock, THREAD); 825 update_dictionary(d_index, d_hash, p_index, p_hash, 826 k, class_loader, THREAD); 827 } 828 829 if (JvmtiExport::should_post_class_load()) { 830 Thread *thread = THREAD; 831 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 832 JvmtiExport::post_class_load((JavaThread *) thread, k()); 833 } 834 } 835 } 836 } // load_instance_class loop 837 838 if (load_instance_added == true) { 839 // clean up placeholder entries for LOAD_INSTANCE success or error 840 // This brackets the SystemDictionary updates for both defining 841 // and initiating loaders 842 MutexLocker mu(SystemDictionary_lock, THREAD); 843 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 844 SystemDictionary_lock->notify_all(); 845 } 846 } 847 848 if (HAS_PENDING_EXCEPTION || k.is_null()) { 849 return NULL; 850 } 851 852 post_class_load_event(class_load_start_time, k, class_loader); 853 854 #ifdef ASSERT 855 { 856 ClassLoaderData* loader_data = k->class_loader_data(); 857 MutexLocker mu(SystemDictionary_lock, THREAD); 858 Klass* kk = find_class(name, loader_data); 859 assert(kk == k(), "should be present in dictionary"); 860 } 861 #endif 862 863 // return if the protection domain in NULL 864 if (protection_domain() == NULL) return k(); 865 866 // Check the protection domain has the right access 867 { 868 MutexLocker mu(SystemDictionary_lock, THREAD); 869 // Note that we have an entry, and entries can be deleted only during GC, 870 // so we cannot allow GC to occur while we're holding this entry. 871 // We're using a No_Safepoint_Verifier to catch any place where we 872 // might potentially do a GC at all. 873 // Dictionary::do_unloading() asserts that classes in SD are only 874 // unloaded at a safepoint. Anonymous classes are not in SD. 875 No_Safepoint_Verifier nosafepoint; 876 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 877 loader_data, 878 protection_domain)) { 879 return k(); 880 } 881 } 882 883 // Verify protection domain. If it fails an exception is thrown 884 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 885 886 return k(); 887 } 888 889 890 // This routine does not lock the system dictionary. 891 // 892 // Since readers don't hold a lock, we must make sure that system 893 // dictionary entries are only removed at a safepoint (when only one 894 // thread is running), and are added to in a safe way (all links must 895 // be updated in an MT-safe manner). 896 // 897 // Callers should be aware that an entry could be added just after 898 // _dictionary->bucket(index) is read here, so the caller will not see 899 // the new entry. 900 901 Klass* SystemDictionary::find(Symbol* class_name, 902 Handle class_loader, 903 Handle protection_domain, 904 TRAPS) { 905 906 // UseNewReflection 907 // The result of this call should be consistent with the result 908 // of the call to resolve_instance_class_or_null(). 909 // See evaluation 6790209 and 4474172 for more details. 910 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 911 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 912 913 if (loader_data == NULL) { 914 // If the ClassLoaderData has not been setup, 915 // then the class loader has no entries in the dictionary. 916 return NULL; 917 } 918 919 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 920 int d_index = dictionary()->hash_to_index(d_hash); 921 922 { 923 // Note that we have an entry, and entries can be deleted only during GC, 924 // so we cannot allow GC to occur while we're holding this entry. 925 // We're using a No_Safepoint_Verifier to catch any place where we 926 // might potentially do a GC at all. 927 // Dictionary::do_unloading() asserts that classes in SD are only 928 // unloaded at a safepoint. Anonymous classes are not in SD. 929 No_Safepoint_Verifier nosafepoint; 930 return dictionary()->find(d_index, d_hash, class_name, loader_data, 931 protection_domain, THREAD); 932 } 933 } 934 935 936 // Look for a loaded instance or array klass by name. Do not do any loading. 937 // return NULL in case of error. 938 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 939 Handle class_loader, 940 Handle protection_domain, 941 TRAPS) { 942 Klass* k = NULL; 943 assert(class_name != NULL, "class name must be non NULL"); 944 945 if (FieldType::is_array(class_name)) { 946 // The name refers to an array. Parse the name. 947 // dimension and object_key in FieldArrayInfo are assigned as a 948 // side-effect of this call 949 FieldArrayInfo fd; 950 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 951 if (t != T_OBJECT) { 952 k = Universe::typeArrayKlassObj(t); 953 } else { 954 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 955 } 956 if (k != NULL) { 957 k = k->array_klass_or_null(fd.dimension()); 958 } 959 } else { 960 k = find(class_name, class_loader, protection_domain, THREAD); 961 } 962 return k; 963 } 964 965 // Note: this method is much like resolve_from_stream, but 966 // updates no supplemental data structures. 967 // TODO consolidate the two methods with a helper routine? 968 Klass* SystemDictionary::parse_stream(Symbol* class_name, 969 Handle class_loader, 970 Handle protection_domain, 971 ClassFileStream* st, 972 KlassHandle host_klass, 973 GrowableArray<Handle>* cp_patches, 974 TRAPS) { 975 TempNewSymbol parsed_name = NULL; 976 977 Ticks class_load_start_time = Ticks::now(); 978 979 ClassLoaderData* loader_data; 980 if (host_klass.not_null()) { 981 // Create a new CLD for anonymous class, that uses the same class loader 982 // as the host_klass 983 assert(EnableInvokeDynamic, ""); 984 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 985 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping"); 986 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 987 loader_data->record_dependency(host_klass(), CHECK_NULL); 988 } else { 989 loader_data = ClassLoaderData::class_loader_data(class_loader()); 990 } 991 992 // Parse the stream. Note that we do this even though this klass might 993 // already be present in the SystemDictionary, otherwise we would not 994 // throw potential ClassFormatErrors. 995 // 996 // Note: "name" is updated. 997 998 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 999 loader_data, 1000 protection_domain, 1001 host_klass, 1002 cp_patches, 1003 parsed_name, 1004 true, 1005 THREAD); 1006 1007 1008 if (host_klass.not_null() && k.not_null()) { 1009 assert(EnableInvokeDynamic, ""); 1010 // If it's anonymous, initialize it now, since nobody else will. 1011 1012 { 1013 MutexLocker mu_r(Compile_lock, THREAD); 1014 1015 // Add to class hierarchy, initialize vtables, and do possible 1016 // deoptimizations. 1017 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1018 1019 // But, do not add to system dictionary. 1020 1021 // compiled code dependencies need to be validated anyway 1022 notice_modification(); 1023 } 1024 1025 // Rewrite and patch constant pool here. 1026 k->link_class(CHECK_NULL); 1027 if (cp_patches != NULL) { 1028 k->constants()->patch_resolved_references(cp_patches); 1029 } 1030 k->eager_initialize(CHECK_NULL); 1031 1032 // notify jvmti 1033 if (JvmtiExport::should_post_class_load()) { 1034 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1035 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1036 } 1037 1038 post_class_load_event(class_load_start_time, k, class_loader); 1039 } 1040 assert(host_klass.not_null() || cp_patches == NULL, 1041 "cp_patches only found with host_klass"); 1042 1043 return k(); 1044 } 1045 1046 // Add a klass to the system from a stream (called by jni_DefineClass and 1047 // JVM_DefineClass). 1048 // Note: class_name can be NULL. In that case we do not know the name of 1049 // the class until we have parsed the stream. 1050 1051 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1052 Handle class_loader, 1053 Handle protection_domain, 1054 ClassFileStream* st, 1055 bool verify, 1056 TRAPS) { 1057 1058 // Classloaders that support parallelism, e.g. bootstrap classloader, 1059 // or all classloaders with UnsyncloadClass do not acquire lock here 1060 bool DoObjectLock = true; 1061 if (is_parallelCapable(class_loader)) { 1062 DoObjectLock = false; 1063 } 1064 1065 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1066 1067 // Make sure we are synchronized on the class loader before we proceed 1068 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1069 check_loader_lock_contention(lockObject, THREAD); 1070 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1071 1072 TempNewSymbol parsed_name = NULL; 1073 1074 // Parse the stream. Note that we do this even though this klass might 1075 // already be present in the SystemDictionary, otherwise we would not 1076 // throw potential ClassFormatErrors. 1077 // 1078 // Note: "name" is updated. 1079 1080 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1081 loader_data, 1082 protection_domain, 1083 parsed_name, 1084 verify, 1085 THREAD); 1086 1087 const char* pkg = "java/"; 1088 if (!HAS_PENDING_EXCEPTION && 1089 !class_loader.is_null() && 1090 parsed_name != NULL && 1091 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1092 // It is illegal to define classes in the "java." package from 1093 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1094 ResourceMark rm(THREAD); 1095 char* name = parsed_name->as_C_string(); 1096 char* index = strrchr(name, '/'); 1097 *index = '\0'; // chop to just the package name 1098 while ((index = strchr(name, '/')) != NULL) { 1099 *index = '.'; // replace '/' with '.' in package name 1100 } 1101 const char* fmt = "Prohibited package name: %s"; 1102 size_t len = strlen(fmt) + strlen(name); 1103 char* message = NEW_RESOURCE_ARRAY(char, len); 1104 jio_snprintf(message, len, fmt, name); 1105 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1106 vmSymbols::java_lang_SecurityException(), message); 1107 } 1108 1109 if (!HAS_PENDING_EXCEPTION) { 1110 assert(parsed_name != NULL, "Sanity"); 1111 assert(class_name == NULL || class_name == parsed_name, "name mismatch"); 1112 // Verification prevents us from creating names with dots in them, this 1113 // asserts that that's the case. 1114 assert(is_internal_format(parsed_name), 1115 "external class name format used internally"); 1116 1117 // Add class just loaded 1118 // If a class loader supports parallel classloading handle parallel define requests 1119 // find_or_define_instance_class may return a different InstanceKlass 1120 if (is_parallelCapable(class_loader)) { 1121 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); 1122 } else { 1123 define_instance_class(k, THREAD); 1124 } 1125 } 1126 1127 // Make sure we have an entry in the SystemDictionary on success 1128 debug_only( { 1129 if (!HAS_PENDING_EXCEPTION) { 1130 assert(parsed_name != NULL, "parsed_name is still null?"); 1131 Symbol* h_name = k->name(); 1132 ClassLoaderData *defining_loader_data = k->class_loader_data(); 1133 1134 MutexLocker mu(SystemDictionary_lock, THREAD); 1135 1136 Klass* check = find_class(parsed_name, loader_data); 1137 assert(check == k(), "should be present in the dictionary"); 1138 1139 Klass* check2 = find_class(h_name, defining_loader_data); 1140 assert(check == check2, "name inconsistancy in SystemDictionary"); 1141 } 1142 } ); 1143 1144 return k(); 1145 } 1146 1147 #if INCLUDE_CDS 1148 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1149 int number_of_entries) { 1150 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1151 "bad shared dictionary size."); 1152 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1153 } 1154 1155 1156 // If there is a shared dictionary, then find the entry for the 1157 // given shared system class, if any. 1158 1159 Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1160 if (shared_dictionary() != NULL) { 1161 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1162 int d_index = shared_dictionary()->hash_to_index(d_hash); 1163 1164 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1165 } else { 1166 return NULL; 1167 } 1168 } 1169 1170 1171 // Load a class from the shared spaces (found through the shared system 1172 // dictionary). Force the superclass and all interfaces to be loaded. 1173 // Update the class definition to include sibling classes and no 1174 // subclasses (yet). [Classes in the shared space are not part of the 1175 // object hierarchy until loaded.] 1176 1177 instanceKlassHandle SystemDictionary::load_shared_class( 1178 Symbol* class_name, Handle class_loader, TRAPS) { 1179 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1180 // Make sure we only return the boot class for the NULL classloader. 1181 if (ik.not_null() && 1182 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) { 1183 Handle protection_domain; 1184 return load_shared_class(ik, class_loader, protection_domain, THREAD); 1185 } 1186 return instanceKlassHandle(); 1187 } 1188 1189 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik, 1190 Handle class_loader, 1191 Handle protection_domain, TRAPS) { 1192 if (ik.not_null()) { 1193 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1194 Symbol* class_name = ik->name(); 1195 1196 // Found the class, now load the superclass and interfaces. If they 1197 // are shared, add them to the main system dictionary and reset 1198 // their hierarchy references (supers, subs, and interfaces). 1199 1200 if (ik->super() != NULL) { 1201 Symbol* cn = ik->super()->name(); 1202 Klass *s = resolve_super_or_fail(class_name, cn, 1203 class_loader, protection_domain, true, CHECK_(nh)); 1204 if (s != ik->super()) { 1205 // The dynamically resolved super class is not the same as the one we used during dump time, 1206 // so we cannot use ik. 1207 return nh; 1208 } 1209 } 1210 1211 Array<Klass*>* interfaces = ik->local_interfaces(); 1212 int num_interfaces = interfaces->length(); 1213 for (int index = 0; index < num_interfaces; index++) { 1214 Klass* k = interfaces->at(index); 1215 1216 // Note: can not use InstanceKlass::cast here because 1217 // interfaces' InstanceKlass's C++ vtbls haven't been 1218 // reinitialized yet (they will be once the interface classes 1219 // are loaded) 1220 Symbol* name = k->name(); 1221 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh)); 1222 if (k != i) { 1223 // The dynamically resolved interface class is not the same as the one we used during dump time, 1224 // so we cannot use ik. 1225 return nh; 1226 } 1227 } 1228 1229 // Adjust methods to recover missing data. They need addresses for 1230 // interpreter entry points and their default native method address 1231 // must be reset. 1232 1233 // Updating methods must be done under a lock so multiple 1234 // threads don't update these in parallel 1235 // 1236 // Shared classes are all currently loaded by either the bootstrap or 1237 // internal parallel class loaders, so this will never cause a deadlock 1238 // on a custom class loader lock. 1239 1240 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 1241 { 1242 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1243 check_loader_lock_contention(lockObject, THREAD); 1244 ObjectLocker ol(lockObject, THREAD, true); 1245 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh)); 1246 } 1247 1248 if (TraceClassLoading) { 1249 ResourceMark rm; 1250 tty->print("[Loaded %s", ik->external_name()); 1251 tty->print(" from shared objects file"); 1252 if (class_loader.not_null()) { 1253 tty->print(" by %s", loader_data->loader_name()); 1254 } 1255 tty->print_cr("]"); 1256 } 1257 1258 if (DumpLoadedClassList != NULL && classlist_file->is_open()) { 1259 // Only dump the classes that can be stored into CDS archive 1260 if (SystemDictionaryShared::is_sharing_possible(loader_data)) { 1261 ResourceMark rm(THREAD); 1262 classlist_file->print_cr("%s", ik->name()->as_C_string()); 1263 classlist_file->flush(); 1264 } 1265 } 1266 1267 // notify a class loaded from shared object 1268 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()), 1269 true /* shared class */); 1270 } 1271 return ik; 1272 } 1273 #endif // INCLUDE_CDS 1274 1275 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1276 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1277 if (class_loader.is_null()) { 1278 1279 // Search the shared system dictionary for classes preloaded into the 1280 // shared spaces. 1281 instanceKlassHandle k; 1282 { 1283 #if INCLUDE_CDS 1284 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1285 k = load_shared_class(class_name, class_loader, THREAD); 1286 #endif 1287 } 1288 1289 if (k.is_null()) { 1290 // Use VM class loader 1291 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1292 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); 1293 } 1294 1295 // find_or_define_instance_class may return a different InstanceKlass 1296 if (!k.is_null()) { 1297 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1298 } 1299 return k; 1300 } else { 1301 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1302 ResourceMark rm(THREAD); 1303 1304 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1305 JavaThread* jt = (JavaThread*) THREAD; 1306 1307 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1308 ClassLoader::perf_app_classload_selftime(), 1309 ClassLoader::perf_app_classload_count(), 1310 jt->get_thread_stat()->perf_recursion_counts_addr(), 1311 jt->get_thread_stat()->perf_timers_addr(), 1312 PerfClassTraceTime::CLASS_LOAD); 1313 1314 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1315 // Translate to external class name format, i.e., convert '/' chars to '.' 1316 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1317 1318 JavaValue result(T_OBJECT); 1319 1320 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1321 1322 // Call public unsynchronized loadClass(String) directly for all class loaders 1323 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1324 // acquire a class-name based lock rather than the class loader object lock. 1325 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1326 // so the call to loadClassInternal() was not required. 1327 // 1328 // UnsyncloadClass flag means both call loadClass(String) and do 1329 // not acquire the class loader lock even for class loaders that are 1330 // not parallelCapable. This was a risky transitional 1331 // flag for diagnostic purposes only. It is risky to call 1332 // custom class loaders without synchronization. 1333 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1334 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1335 // Do NOT assume this will be supported in future releases. 1336 // 1337 // Added MustCallLoadClassInternal in case we discover in the field 1338 // a customer that counts on this call 1339 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1340 JavaCalls::call_special(&result, 1341 class_loader, 1342 spec_klass, 1343 vmSymbols::loadClassInternal_name(), 1344 vmSymbols::string_class_signature(), 1345 string, 1346 CHECK_(nh)); 1347 } else { 1348 JavaCalls::call_virtual(&result, 1349 class_loader, 1350 spec_klass, 1351 vmSymbols::loadClass_name(), 1352 vmSymbols::string_class_signature(), 1353 string, 1354 CHECK_(nh)); 1355 } 1356 1357 assert(result.get_type() == T_OBJECT, "just checking"); 1358 oop obj = (oop) result.get_jobject(); 1359 1360 // Primitive classes return null since forName() can not be 1361 // used to obtain any of the Class objects representing primitives or void 1362 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1363 instanceKlassHandle k = 1364 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1365 // For user defined Java class loaders, check that the name returned is 1366 // the same as that requested. This check is done for the bootstrap 1367 // loader when parsing the class file. 1368 if (class_name == k->name()) { 1369 return k; 1370 } 1371 } 1372 // Class is not found or has the wrong name, return NULL 1373 return nh; 1374 } 1375 } 1376 1377 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1378 1379 ClassLoaderData* loader_data = k->class_loader_data(); 1380 Handle class_loader_h(THREAD, loader_data->class_loader()); 1381 1382 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){} 1383 1384 // for bootstrap and other parallel classloaders don't acquire lock, 1385 // use placeholder token 1386 // If a parallelCapable class loader calls define_instance_class instead of 1387 // find_or_define_instance_class to get here, we have a timing 1388 // hole with systemDictionary updates and check_constraints 1389 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1390 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1391 compute_loader_lock_object(class_loader_h, THREAD)), 1392 "define called without lock"); 1393 } 1394 1395 // Check class-loading constraints. Throw exception if violation is detected. 1396 // Grabs and releases SystemDictionary_lock 1397 // The check_constraints/find_class call and update_dictionary sequence 1398 // must be "atomic" for a specific class/classloader pair so we never 1399 // define two different instanceKlasses for that class/classloader pair. 1400 // Existing classloaders will call define_instance_class with the 1401 // classloader lock held 1402 // Parallel classloaders will call find_or_define_instance_class 1403 // which will require a token to perform the define class 1404 Symbol* name_h = k->name(); 1405 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1406 int d_index = dictionary()->hash_to_index(d_hash); 1407 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1408 1409 // Register class just loaded with class loader (placed in Vector) 1410 // Note we do this before updating the dictionary, as this can 1411 // fail with an OutOfMemoryError (if it does, we will *not* put this 1412 // class in the dictionary and will not update the class hierarchy). 1413 // JVMTI FollowReferences needs to find the classes this way. 1414 if (k->class_loader() != NULL) { 1415 methodHandle m(THREAD, Universe::loader_addClass_method()); 1416 JavaValue result(T_VOID); 1417 JavaCallArguments args(class_loader_h); 1418 args.push_oop(Handle(THREAD, k->java_mirror())); 1419 JavaCalls::call(&result, m, &args, CHECK); 1420 } 1421 1422 // Add the new class. We need recompile lock during update of CHA. 1423 { 1424 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1425 int p_index = placeholders()->hash_to_index(p_hash); 1426 1427 MutexLocker mu_r(Compile_lock, THREAD); 1428 1429 // Add to class hierarchy, initialize vtables, and do possible 1430 // deoptimizations. 1431 add_to_hierarchy(k, CHECK); // No exception, but can block 1432 1433 // Add to systemDictionary - so other classes can see it. 1434 // Grabs and releases SystemDictionary_lock 1435 update_dictionary(d_index, d_hash, p_index, p_hash, 1436 k, class_loader_h, THREAD); 1437 } 1438 k->eager_initialize(THREAD); 1439 1440 // notify jvmti 1441 if (JvmtiExport::should_post_class_load()) { 1442 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1443 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1444 1445 } 1446 1447 } 1448 1449 // Support parallel classloading 1450 // All parallel class loaders, including bootstrap classloader 1451 // lock a placeholder entry for this class/class_loader pair 1452 // to allow parallel defines of different classes for this class loader 1453 // With AllowParallelDefine flag==true, in case they do not synchronize around 1454 // FindLoadedClass/DefineClass, calls, we check for parallel 1455 // loading for them, wait if a defineClass is in progress 1456 // and return the initial requestor's results 1457 // This flag does not apply to the bootstrap classloader. 1458 // With AllowParallelDefine flag==false, call through to define_instance_class 1459 // which will throw LinkageError: duplicate class definition. 1460 // False is the requested default. 1461 // For better performance, the class loaders should synchronize 1462 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1463 // potentially waste time reading and parsing the bytestream. 1464 // Note: VM callers should ensure consistency of k/class_name,class_loader 1465 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1466 1467 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1468 Symbol* name_h = k->name(); // passed in class_name may be null 1469 ClassLoaderData* loader_data = class_loader_data(class_loader); 1470 1471 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1472 int d_index = dictionary()->hash_to_index(d_hash); 1473 1474 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1475 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1476 int p_index = placeholders()->hash_to_index(p_hash); 1477 PlaceholderEntry* probe; 1478 1479 { 1480 MutexLocker mu(SystemDictionary_lock, THREAD); 1481 // First check if class already defined 1482 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1483 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1484 if (check != NULL) { 1485 return(instanceKlassHandle(THREAD, check)); 1486 } 1487 } 1488 1489 // Acquire define token for this class/classloader 1490 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1491 // Wait if another thread defining in parallel 1492 // All threads wait - even those that will throw duplicate class: otherwise 1493 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1494 // if other thread has not finished updating dictionary 1495 while (probe->definer() != NULL) { 1496 SystemDictionary_lock->wait(); 1497 } 1498 // Only special cases allow parallel defines and can use other thread's results 1499 // Other cases fall through, and may run into duplicate defines 1500 // caught by finding an entry in the SystemDictionary 1501 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1502 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1503 SystemDictionary_lock->notify_all(); 1504 #ifdef ASSERT 1505 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1506 assert(check != NULL, "definer missed recording success"); 1507 #endif 1508 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1509 } else { 1510 // This thread will define the class (even if earlier thread tried and had an error) 1511 probe->set_definer(THREAD); 1512 } 1513 } 1514 1515 define_instance_class(k, THREAD); 1516 1517 Handle linkage_exception = Handle(); // null handle 1518 1519 // definer must notify any waiting threads 1520 { 1521 MutexLocker mu(SystemDictionary_lock, THREAD); 1522 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1523 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1524 if (probe != NULL) { 1525 if (HAS_PENDING_EXCEPTION) { 1526 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1527 CLEAR_PENDING_EXCEPTION; 1528 } else { 1529 probe->set_instance_klass(k()); 1530 } 1531 probe->set_definer(NULL); 1532 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1533 SystemDictionary_lock->notify_all(); 1534 } 1535 } 1536 1537 // Can't throw exception while holding lock due to rank ordering 1538 if (linkage_exception() != NULL) { 1539 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1540 } 1541 1542 return k; 1543 } 1544 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1545 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1546 if (class_loader.is_null()) { 1547 return Handle(THREAD, _system_loader_lock_obj); 1548 } else { 1549 return class_loader; 1550 } 1551 } 1552 1553 // This method is added to check how often we have to wait to grab loader 1554 // lock. The results are being recorded in the performance counters defined in 1555 // ClassLoader::_sync_systemLoaderLockContentionRate and 1556 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1557 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1558 if (!UsePerfData) { 1559 return; 1560 } 1561 1562 assert(!loader_lock.is_null(), "NULL lock object"); 1563 1564 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1565 == ObjectSynchronizer::owner_other) { 1566 // contention will likely happen, so increment the corresponding 1567 // contention counter. 1568 if (loader_lock() == _system_loader_lock_obj) { 1569 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1570 } else { 1571 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1572 } 1573 } 1574 } 1575 1576 // ---------------------------------------------------------------------------- 1577 // Lookup 1578 1579 Klass* SystemDictionary::find_class(int index, unsigned int hash, 1580 Symbol* class_name, 1581 ClassLoaderData* loader_data) { 1582 assert_locked_or_safepoint(SystemDictionary_lock); 1583 assert (index == dictionary()->index_for(class_name, loader_data), 1584 "incorrect index?"); 1585 1586 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1587 return k; 1588 } 1589 1590 1591 // Basic find on classes in the midst of being loaded 1592 Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1593 ClassLoaderData* loader_data) { 1594 assert_locked_or_safepoint(SystemDictionary_lock); 1595 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1596 int p_index = placeholders()->hash_to_index(p_hash); 1597 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1598 } 1599 1600 1601 // Used for assertions and verification only 1602 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1603 #ifndef ASSERT 1604 guarantee(VerifyBeforeGC || 1605 VerifyDuringGC || 1606 VerifyBeforeExit || 1607 VerifyDuringStartup || 1608 VerifyAfterGC, "too expensive"); 1609 #endif 1610 assert_locked_or_safepoint(SystemDictionary_lock); 1611 1612 // First look in the loaded class array 1613 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1614 int d_index = dictionary()->hash_to_index(d_hash); 1615 return find_class(d_index, d_hash, class_name, loader_data); 1616 } 1617 1618 1619 // Get the next class in the diictionary. 1620 Klass* SystemDictionary::try_get_next_class() { 1621 return dictionary()->try_get_next_class(); 1622 } 1623 1624 1625 // ---------------------------------------------------------------------------- 1626 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1627 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1628 // before a new class is used. 1629 1630 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1631 assert(k.not_null(), "just checking"); 1632 assert_locked_or_safepoint(Compile_lock); 1633 1634 // Link into hierachy. Make sure the vtables are initialized before linking into 1635 k->append_to_sibling_list(); // add to superklass/sibling list 1636 k->process_interfaces(THREAD); // handle all "implements" declarations 1637 k->set_init_state(InstanceKlass::loaded); 1638 // Now flush all code that depended on old class hierarchy. 1639 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1640 // Also, first reinitialize vtable because it may have gotten out of synch 1641 // while the new class wasn't connected to the class hierarchy. 1642 Universe::flush_dependents_on(k); 1643 } 1644 1645 // ---------------------------------------------------------------------------- 1646 // GC support 1647 1648 // Following roots during mark-sweep is separated in two phases. 1649 // 1650 // The first phase follows preloaded classes and all other system 1651 // classes, since these will never get unloaded anyway. 1652 // 1653 // The second phase removes (unloads) unreachable classes from the 1654 // system dictionary and follows the remaining classes' contents. 1655 1656 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1657 roots_oops_do(blk, NULL); 1658 } 1659 1660 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1661 // Follow all system classes and temporary placeholders in dictionary 1662 dictionary()->always_strong_classes_do(closure); 1663 1664 // Placeholders. These represent classes we're actively loading. 1665 placeholders()->classes_do(closure); 1666 } 1667 1668 // Calculate a "good" systemdictionary size based 1669 // on predicted or current loaded classes count 1670 int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1671 int newsize = _old_default_sdsize; 1672 if ((classcount > 0) && !DumpSharedSpaces) { 1673 int desiredsize = classcount/_average_depth_goal; 1674 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1675 newsize = _primelist[++_sdgeneration]) { 1676 if (desiredsize <= newsize) { 1677 break; 1678 } 1679 } 1680 } 1681 return newsize; 1682 } 1683 1684 #ifdef ASSERT 1685 class VerifySDReachableAndLiveClosure : public OopClosure { 1686 private: 1687 BoolObjectClosure* _is_alive; 1688 1689 template <class T> void do_oop_work(T* p) { 1690 oop obj = oopDesc::load_decode_heap_oop(p); 1691 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); 1692 } 1693 1694 public: 1695 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1696 1697 virtual void do_oop(oop* p) { do_oop_work(p); } 1698 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1699 }; 1700 #endif 1701 1702 // Assumes classes in the SystemDictionary are only unloaded at a safepoint 1703 // Note: anonymous classes are not in the SD. 1704 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) { 1705 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1706 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive); 1707 if (unloading_occurred) { 1708 dictionary()->do_unloading(); 1709 constraints()->purge_loader_constraints(); 1710 resolution_errors()->purge_resolution_errors(); 1711 } 1712 // Oops referenced by the system dictionary may get unreachable independently 1713 // of the class loader (eg. cached protection domain oops). So we need to 1714 // explicitly unlink them here instead of in Dictionary::do_unloading. 1715 dictionary()->unlink(is_alive); 1716 #ifdef ASSERT 1717 VerifySDReachableAndLiveClosure cl(is_alive); 1718 dictionary()->oops_do(&cl); 1719 #endif 1720 return unloading_occurred; 1721 } 1722 1723 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { 1724 strong->do_oop(&_java_system_loader); 1725 strong->do_oop(&_system_loader_lock_obj); 1726 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) 1727 1728 // Adjust dictionary 1729 dictionary()->roots_oops_do(strong, weak); 1730 1731 // Visit extra methods 1732 invoke_method_table()->oops_do(strong); 1733 } 1734 1735 void SystemDictionary::oops_do(OopClosure* f) { 1736 f->do_oop(&_java_system_loader); 1737 f->do_oop(&_system_loader_lock_obj); 1738 CDS_ONLY(SystemDictionaryShared::oops_do(f);) 1739 1740 // Adjust dictionary 1741 dictionary()->oops_do(f); 1742 1743 // Visit extra methods 1744 invoke_method_table()->oops_do(f); 1745 } 1746 1747 // Extended Class redefinition support. 1748 // If one of these classes is replaced, we need to replace it in these places. 1749 // KlassClosure::do_klass should take the address of a class but we can 1750 // change that later. 1751 void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 1752 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 1753 f->do_klass(_well_known_klasses[k]); 1754 } 1755 1756 { 1757 for (int i = 0; i < T_VOID+1; i++) { 1758 if (_box_klasses[i] != NULL) { 1759 assert(i >= T_BOOLEAN, "checking"); 1760 f->do_klass(_box_klasses[i]); 1761 } 1762 } 1763 } 1764 1765 FilteredFieldsMap::classes_do(f); 1766 } 1767 1768 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 1769 f->do_klass(_abstract_ownable_synchronizer_klass); 1770 } 1771 1772 // Just the classes from defining class loaders 1773 // Don't iterate over placeholders 1774 void SystemDictionary::classes_do(void f(Klass*)) { 1775 dictionary()->classes_do(f); 1776 } 1777 1778 // Added for initialize_itable_for_klass 1779 // Just the classes from defining class loaders 1780 // Don't iterate over placeholders 1781 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 1782 dictionary()->classes_do(f, CHECK); 1783 } 1784 1785 // All classes, and their class loaders 1786 // Don't iterate over placeholders 1787 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 1788 dictionary()->classes_do(f); 1789 } 1790 1791 void SystemDictionary::placeholders_do(void f(Symbol*)) { 1792 placeholders()->entries_do(f); 1793 } 1794 1795 void SystemDictionary::methods_do(void f(Method*)) { 1796 dictionary()->methods_do(f); 1797 invoke_method_table()->methods_do(f); 1798 } 1799 1800 void SystemDictionary::remove_classes_in_error_state() { 1801 dictionary()->remove_classes_in_error_state(); 1802 } 1803 1804 // ---------------------------------------------------------------------------- 1805 // Lazily load klasses 1806 1807 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1808 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); 1809 1810 // if multiple threads calling this function, only one thread will load 1811 // the class. The other threads will find the loaded version once the 1812 // class is loaded. 1813 Klass* aos = _abstract_ownable_synchronizer_klass; 1814 if (aos == NULL) { 1815 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1816 // Force a fence to prevent any read before the write completes 1817 OrderAccess::fence(); 1818 _abstract_ownable_synchronizer_klass = k; 1819 } 1820 } 1821 1822 // ---------------------------------------------------------------------------- 1823 // Initialization 1824 1825 void SystemDictionary::initialize(TRAPS) { 1826 // Allocate arrays 1827 assert(dictionary() == NULL, 1828 "SystemDictionary should only be initialized once"); 1829 _sdgeneration = 0; 1830 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 1831 _placeholders = new PlaceholderTable(_nof_buckets); 1832 _number_of_modifications = 0; 1833 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1834 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1835 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1836 1837 // Allocate private object used as system class loader lock 1838 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1839 // Initialize basic classes 1840 initialize_preloaded_classes(CHECK); 1841 } 1842 1843 // Compact table of directions on the initialization of klasses: 1844 static const short wk_init_info[] = { 1845 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1846 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1847 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1848 | (int)SystemDictionary::option ), 1849 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1850 #undef WK_KLASS_INIT_INFO 1851 0 1852 }; 1853 1854 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 1855 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1856 int info = wk_init_info[id - FIRST_WKID]; 1857 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1858 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1859 Klass** klassp = &_well_known_klasses[id]; 1860 bool must_load = (init_opt < SystemDictionary::Opt); 1861 if ((*klassp) == NULL) { 1862 if (must_load) { 1863 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class 1864 } else { 1865 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass 1866 } 1867 } 1868 return ((*klassp) != NULL); 1869 } 1870 1871 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1872 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1873 for (int id = (int)start_id; id < (int)limit_id; id++) { 1874 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1875 int info = wk_init_info[id - FIRST_WKID]; 1876 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1877 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1878 1879 initialize_wk_klass((WKID)id, opt, CHECK); 1880 } 1881 1882 // move the starting value forward to the limit: 1883 start_id = limit_id; 1884 } 1885 1886 void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1887 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 1888 // Preload commonly used klasses 1889 WKID scan = FIRST_WKID; 1890 // first do Object, then String, Class 1891 if (UseSharedSpaces) { 1892 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1893 // Initialize the constant pool for the Object_class 1894 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 1895 ik->constants()->restore_unshareable_info(CHECK); 1896 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1897 } else { 1898 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1899 } 1900 1901 // Calculate offsets for String and Class classes since they are loaded and 1902 // can be used after this point. 1903 java_lang_String::compute_offsets(); 1904 java_lang_Class::compute_offsets(); 1905 1906 // Fixup mirrors for classes loaded before java.lang.Class. 1907 // These calls iterate over the objects currently in the perm gen 1908 // so calling them at this point is matters (not before when there 1909 // are fewer objects and not later after there are more objects 1910 // in the perm gen. 1911 Universe::initialize_basic_type_mirrors(CHECK); 1912 Universe::fixup_mirrors(CHECK); 1913 1914 // do a bunch more: 1915 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 1916 1917 // Preload ref klasses and set reference types 1918 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 1919 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 1920 1921 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK); 1922 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 1923 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 1924 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 1925 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 1926 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER); 1927 1928 // JSR 292 classes 1929 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 1930 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 1931 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 1932 if (EnableInvokeDynamic) { 1933 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 1934 } else { 1935 // Skip the JSR 292 classes, if not enabled. 1936 scan = WKID(jsr292_group_end + 1); 1937 } 1938 1939 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); 1940 1941 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 1942 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 1943 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 1944 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 1945 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 1946 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 1947 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 1948 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 1949 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 1950 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 1951 1952 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 1953 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 1954 _has_loadClassInternal = (method != NULL); 1955 } 1956 { // Compute whether we should use checkPackageAccess or NOT 1957 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 1958 _has_checkPackageAccess = (method != NULL); 1959 } 1960 } 1961 1962 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 1963 // If so, returns the basic type it holds. If not, returns T_OBJECT. 1964 BasicType SystemDictionary::box_klass_type(Klass* k) { 1965 assert(k != NULL, ""); 1966 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 1967 if (_box_klasses[i] == k) 1968 return (BasicType)i; 1969 } 1970 return T_OBJECT; 1971 } 1972 1973 // Constraints on class loaders. The details of the algorithm can be 1974 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 1975 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 1976 // that the system dictionary needs to maintain a set of contraints that 1977 // must be satisfied by all classes in the dictionary. 1978 // if defining is true, then LinkageError if already in systemDictionary 1979 // if initiating loader, then ok if InstanceKlass matches existing entry 1980 1981 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 1982 instanceKlassHandle k, 1983 Handle class_loader, bool defining, 1984 TRAPS) { 1985 const char *linkage_error = NULL; 1986 { 1987 Symbol* name = k->name(); 1988 ClassLoaderData *loader_data = class_loader_data(class_loader); 1989 1990 MutexLocker mu(SystemDictionary_lock, THREAD); 1991 1992 Klass* check = find_class(d_index, d_hash, name, loader_data); 1993 if (check != (Klass*)NULL) { 1994 // if different InstanceKlass - duplicate class definition, 1995 // else - ok, class loaded by a different thread in parallel, 1996 // we should only have found it if it was done loading and ok to use 1997 // system dictionary only holds instance classes, placeholders 1998 // also holds array classes 1999 2000 assert(check->oop_is_instance(), "noninstance in systemdictionary"); 2001 if ((defining == true) || (k() != check)) { 2002 linkage_error = "loader (instance of %s): attempted duplicate class " 2003 "definition for name: \"%s\""; 2004 } else { 2005 return; 2006 } 2007 } 2008 2009 #ifdef ASSERT 2010 Symbol* ph_check = find_placeholder(name, loader_data); 2011 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 2012 #endif 2013 2014 if (linkage_error == NULL) { 2015 if (constraints()->check_or_update(k, class_loader, name) == false) { 2016 linkage_error = "loader constraint violation: loader (instance of %s)" 2017 " previously initiated loading for a different type with name \"%s\""; 2018 } 2019 } 2020 } 2021 2022 // Throw error now if needed (cannot throw while holding 2023 // SystemDictionary_lock because of rank ordering) 2024 2025 if (linkage_error) { 2026 ResourceMark rm(THREAD); 2027 const char* class_loader_name = loader_name(class_loader()); 2028 char* type_name = k->name()->as_C_string(); 2029 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + 2030 strlen(type_name); 2031 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2032 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); 2033 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2034 } 2035 } 2036 2037 2038 // Update system dictionary - done after check_constraint and add_to_hierachy 2039 // have been called. 2040 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 2041 int p_index, unsigned int p_hash, 2042 instanceKlassHandle k, 2043 Handle class_loader, 2044 TRAPS) { 2045 // Compile_lock prevents systemDictionary updates during compilations 2046 assert_locked_or_safepoint(Compile_lock); 2047 Symbol* name = k->name(); 2048 ClassLoaderData *loader_data = class_loader_data(class_loader); 2049 2050 { 2051 MutexLocker mu1(SystemDictionary_lock, THREAD); 2052 2053 // See whether biased locking is enabled and if so set it for this 2054 // klass. 2055 // Note that this must be done past the last potential blocking 2056 // point / safepoint. We enable biased locking lazily using a 2057 // VM_Operation to iterate the SystemDictionary and installing the 2058 // biasable mark word into each InstanceKlass's prototype header. 2059 // To avoid race conditions where we accidentally miss enabling the 2060 // optimization for one class in the process of being added to the 2061 // dictionary, we must not safepoint after the test of 2062 // BiasedLocking::enabled(). 2063 if (UseBiasedLocking && BiasedLocking::enabled()) { 2064 // Set biased locking bit for all loaded classes; it will be 2065 // cleared if revocation occurs too often for this type 2066 // NOTE that we must only do this when the class is initally 2067 // defined, not each time it is referenced from a new class loader 2068 if (k->class_loader() == class_loader()) { 2069 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2070 } 2071 } 2072 2073 // Make a new system dictionary entry. 2074 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2075 if (sd_check == NULL) { 2076 dictionary()->add_klass(name, loader_data, k); 2077 notice_modification(); 2078 } 2079 #ifdef ASSERT 2080 sd_check = find_class(d_index, d_hash, name, loader_data); 2081 assert (sd_check != NULL, "should have entry in system dictionary"); 2082 // Note: there may be a placeholder entry: for circularity testing 2083 // or for parallel defines 2084 #endif 2085 SystemDictionary_lock->notify_all(); 2086 } 2087 } 2088 2089 2090 // Try to find a class name using the loader constraints. The 2091 // loader constraints might know about a class that isn't fully loaded 2092 // yet and these will be ignored. 2093 Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2094 Symbol* class_name, Handle class_loader, TRAPS) { 2095 2096 // First see if it has been loaded directly. 2097 // Force the protection domain to be null. (This removes protection checks.) 2098 Handle no_protection_domain; 2099 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2100 no_protection_domain, CHECK_NULL); 2101 if (klass != NULL) 2102 return klass; 2103 2104 // Now look to see if it has been loaded elsewhere, and is subject to 2105 // a loader constraint that would require this loader to return the 2106 // klass that is already loaded. 2107 if (FieldType::is_array(class_name)) { 2108 // For array classes, their Klass*s are not kept in the 2109 // constraint table. The element Klass*s are. 2110 FieldArrayInfo fd; 2111 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2112 if (t != T_OBJECT) { 2113 klass = Universe::typeArrayKlassObj(t); 2114 } else { 2115 MutexLocker mu(SystemDictionary_lock, THREAD); 2116 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2117 } 2118 // If element class already loaded, allocate array klass 2119 if (klass != NULL) { 2120 klass = klass->array_klass_or_null(fd.dimension()); 2121 } 2122 } else { 2123 MutexLocker mu(SystemDictionary_lock, THREAD); 2124 // Non-array classes are easy: simply check the constraint table. 2125 klass = constraints()->find_constrained_klass(class_name, class_loader); 2126 } 2127 2128 return klass; 2129 } 2130 2131 2132 bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2133 Handle class_loader1, 2134 Handle class_loader2, 2135 Thread* THREAD) { 2136 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2137 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2138 2139 Symbol* constraint_name = NULL; 2140 if (!FieldType::is_array(class_name)) { 2141 constraint_name = class_name; 2142 } else { 2143 // For array classes, their Klass*s are not kept in the 2144 // constraint table. The element classes are. 2145 FieldArrayInfo fd; 2146 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2147 // primitive types always pass 2148 if (t != T_OBJECT) { 2149 return true; 2150 } else { 2151 constraint_name = fd.object_key(); 2152 } 2153 } 2154 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2155 int d_index1 = dictionary()->hash_to_index(d_hash1); 2156 2157 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2158 int d_index2 = dictionary()->hash_to_index(d_hash2); 2159 { 2160 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2161 2162 // Better never do a GC while we're holding these oops 2163 No_Safepoint_Verifier nosafepoint; 2164 2165 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2166 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2167 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2168 klass2, class_loader2); 2169 } 2170 } 2171 2172 // Add entry to resolution error table to record the error when the first 2173 // attempt to resolve a reference to a class has failed. 2174 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) { 2175 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2176 int index = resolution_errors()->hash_to_index(hash); 2177 { 2178 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2179 resolution_errors()->add_entry(index, hash, pool, which, error); 2180 } 2181 } 2182 2183 // Delete a resolution error for RedefineClasses for a constant pool is going away 2184 void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2185 resolution_errors()->delete_entry(pool); 2186 } 2187 2188 // Lookup resolution error table. Returns error if found, otherwise NULL. 2189 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { 2190 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2191 int index = resolution_errors()->hash_to_index(hash); 2192 { 2193 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2194 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2195 return (entry != NULL) ? entry->error() : (Symbol*)NULL; 2196 } 2197 } 2198 2199 2200 // Signature constraints ensure that callers and callees agree about 2201 // the meaning of type names in their signatures. This routine is the 2202 // intake for constraints. It collects them from several places: 2203 // 2204 // * LinkResolver::resolve_method (if check_access is true) requires 2205 // that the resolving class (the caller) and the defining class of 2206 // the resolved method (the callee) agree on each type in the 2207 // method's signature. 2208 // 2209 // * LinkResolver::resolve_interface_method performs exactly the same 2210 // checks. 2211 // 2212 // * LinkResolver::resolve_field requires that the constant pool 2213 // attempting to link to a field agree with the field's defining 2214 // class about the type of the field signature. 2215 // 2216 // * klassVtable::initialize_vtable requires that, when a class 2217 // overrides a vtable entry allocated by a superclass, that the 2218 // overriding method (i.e., the callee) agree with the superclass 2219 // on each type in the method's signature. 2220 // 2221 // * klassItable::initialize_itable requires that, when a class fills 2222 // in its itables, for each non-abstract method installed in an 2223 // itable, the method (i.e., the callee) agree with the interface 2224 // on each type in the method's signature. 2225 // 2226 // All those methods have a boolean (check_access, checkconstraints) 2227 // which turns off the checks. This is used from specialized contexts 2228 // such as bootstrapping, dumping, and debugging. 2229 // 2230 // No direct constraint is placed between the class and its 2231 // supertypes. Constraints are only placed along linked relations 2232 // between callers and callees. When a method overrides or implements 2233 // an abstract method in a supertype (superclass or interface), the 2234 // constraints are placed as if the supertype were the caller to the 2235 // overriding method. (This works well, since callers to the 2236 // supertype have already established agreement between themselves and 2237 // the supertype.) As a result of all this, a class can disagree with 2238 // its supertype about the meaning of a type name, as long as that 2239 // class neither calls a relevant method of the supertype, nor is 2240 // called (perhaps via an override) from the supertype. 2241 // 2242 // 2243 // SystemDictionary::check_signature_loaders(sig, l1, l2) 2244 // 2245 // Make sure all class components (including arrays) in the given 2246 // signature will be resolved to the same class in both loaders. 2247 // Returns the name of the type that failed a loader constraint check, or 2248 // NULL if no constraint failed. No exception except OOME is thrown. 2249 // Arrays are not added to the loader constraint table, their elements are. 2250 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2251 Handle loader1, Handle loader2, 2252 bool is_method, TRAPS) { 2253 // Nothing to do if loaders are the same. 2254 if (loader1() == loader2()) { 2255 return NULL; 2256 } 2257 2258 SignatureStream sig_strm(signature, is_method); 2259 while (!sig_strm.is_done()) { 2260 if (sig_strm.is_object()) { 2261 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2262 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2263 return sig; 2264 } 2265 } 2266 sig_strm.next(); 2267 } 2268 return NULL; 2269 } 2270 2271 2272 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2273 Symbol* signature, 2274 TRAPS) { 2275 methodHandle empty; 2276 assert(EnableInvokeDynamic, ""); 2277 assert(MethodHandles::is_signature_polymorphic(iid) && 2278 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2279 iid != vmIntrinsics::_invokeGeneric, 2280 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid))); 2281 2282 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2283 int index = invoke_method_table()->hash_to_index(hash); 2284 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2285 methodHandle m; 2286 if (spe == NULL || spe->method() == NULL) { 2287 spe = NULL; 2288 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2289 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2290 if (!Arguments::is_interpreter_only()) { 2291 // Generate a compiled form of the MH intrinsic. 2292 AdapterHandlerLibrary::create_native_wrapper(m); 2293 // Check if have the compiled code. 2294 if (!m->has_compiled_code()) { 2295 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), 2296 "out of space in CodeCache for method handle intrinsic", empty); 2297 } 2298 } 2299 // Now grab the lock. We might have to throw away the new method, 2300 // if a racing thread has managed to install one at the same time. 2301 { 2302 MutexLocker ml(SystemDictionary_lock, THREAD); 2303 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2304 if (spe == NULL) 2305 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2306 if (spe->method() == NULL) 2307 spe->set_method(m()); 2308 } 2309 } 2310 2311 assert(spe != NULL && spe->method() != NULL, ""); 2312 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && 2313 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), 2314 "MH intrinsic invariant"); 2315 return spe->method(); 2316 } 2317 2318 // Helper for unpacking the return value from linkMethod and linkCallSite. 2319 static methodHandle unpack_method_and_appendix(Handle mname, 2320 KlassHandle accessing_klass, 2321 objArrayHandle appendix_box, 2322 Handle* appendix_result, 2323 TRAPS) { 2324 methodHandle empty; 2325 if (mname.not_null()) { 2326 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2327 if (vmtarget != NULL && vmtarget->is_method()) { 2328 Method* m = (Method*)vmtarget; 2329 oop appendix = appendix_box->obj_at(0); 2330 if (TraceMethodHandles) { 2331 #ifndef PRODUCT 2332 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2333 m->print(); 2334 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2335 tty->cr(); 2336 #endif //PRODUCT 2337 } 2338 (*appendix_result) = Handle(THREAD, appendix); 2339 // the target is stored in the cpCache and if a reference to this 2340 // MethodName is dropped we need a way to make sure the 2341 // class_loader containing this method is kept alive. 2342 // FIXME: the appendix might also preserve this dependency. 2343 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2344 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2345 return methodHandle(THREAD, m); 2346 } 2347 } 2348 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2349 return empty; 2350 } 2351 2352 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name, 2353 Symbol* signature, 2354 KlassHandle accessing_klass, 2355 Handle *appendix_result, 2356 Handle *method_type_result, 2357 TRAPS) { 2358 methodHandle empty; 2359 assert(EnableInvokeDynamic, ""); 2360 assert(!THREAD->is_Compiler_thread(), ""); 2361 Handle method_type = 2362 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2363 2364 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass(); 2365 int ref_kind = JVM_REF_invokeVirtual; 2366 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2367 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2368 assert(appendix_box->obj_at(0) == NULL, ""); 2369 2370 // This should not happen. JDK code should take care of that. 2371 if (accessing_klass.is_null() || method_type.is_null()) { 2372 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2373 } 2374 2375 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2376 JavaCallArguments args; 2377 args.push_oop(accessing_klass()->java_mirror()); 2378 args.push_int(ref_kind); 2379 args.push_oop(mh_klass()->java_mirror()); 2380 args.push_oop(name_str()); 2381 args.push_oop(method_type()); 2382 args.push_oop(appendix_box()); 2383 JavaValue result(T_OBJECT); 2384 JavaCalls::call_static(&result, 2385 SystemDictionary::MethodHandleNatives_klass(), 2386 vmSymbols::linkMethod_name(), 2387 vmSymbols::linkMethod_signature(), 2388 &args, CHECK_(empty)); 2389 Handle mname(THREAD, (oop) result.get_jobject()); 2390 (*method_type_result) = method_type; 2391 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2392 } 2393 2394 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. 2395 // We must ensure that all class loaders everywhere will reach this class, for any client. 2396 // This is a safe bet for public classes in java.lang, such as Object and String. 2397 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. 2398 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. 2399 static bool is_always_visible_class(oop mirror) { 2400 Klass* klass = java_lang_Class::as_Klass(mirror); 2401 if (klass->oop_is_objArray()) { 2402 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type 2403 } 2404 if (klass->oop_is_typeArray()) { 2405 return true; // primitive array 2406 } 2407 assert(klass->oop_is_instance(), klass->external_name()); 2408 return klass->is_public() && 2409 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang 2410 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke 2411 } 2412 2413 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2414 // signature, as interpreted relative to the given class loader. 2415 // Because of class loader constraints, all method handle usage must be 2416 // consistent with this loader. 2417 Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2418 KlassHandle accessing_klass, 2419 TRAPS) { 2420 Handle empty; 2421 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2422 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2423 int index = invoke_method_table()->hash_to_index(hash); 2424 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2425 if (spe != NULL && spe->method_type() != NULL) { 2426 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2427 return Handle(THREAD, spe->method_type()); 2428 } else if (THREAD->is_Compiler_thread()) { 2429 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2430 return Handle(); // do not attempt from within compiler, unless it was cached 2431 } 2432 2433 Handle class_loader, protection_domain; 2434 if (accessing_klass.not_null()) { 2435 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2436 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2437 } 2438 bool can_be_cached = true; 2439 int npts = ArgumentCount(signature).size(); 2440 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2441 int arg = 0; 2442 Handle rt; // the return type from the signature 2443 ResourceMark rm(THREAD); 2444 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2445 oop mirror = NULL; 2446 if (can_be_cached) { 2447 // Use neutral class loader to lookup candidate classes to be placed in the cache. 2448 mirror = ss.as_java_mirror(Handle(), Handle(), 2449 SignatureStream::ReturnNull, CHECK_(empty)); 2450 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { 2451 // Fall back to accessing_klass context. 2452 can_be_cached = false; 2453 } 2454 } 2455 if (!can_be_cached) { 2456 // Resolve, throwing a real error if it doesn't work. 2457 mirror = ss.as_java_mirror(class_loader, protection_domain, 2458 SignatureStream::NCDFError, CHECK_(empty)); 2459 } 2460 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string()); 2461 if (ss.at_return_type()) 2462 rt = Handle(THREAD, mirror); 2463 else 2464 pts->obj_at_put(arg++, mirror); 2465 2466 // Check accessibility. 2467 if (ss.is_object() && accessing_klass.not_null()) { 2468 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2469 mirror = NULL; // safety 2470 // Emulate ConstantPool::verify_constant_pool_resolve. 2471 if (sel_klass->oop_is_objArray()) 2472 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2473 if (sel_klass->oop_is_instance()) { 2474 KlassHandle sel_kh(THREAD, sel_klass); 2475 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2476 } 2477 } 2478 } 2479 assert(arg == npts, ""); 2480 2481 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType 2482 JavaCallArguments args(Handle(THREAD, rt())); 2483 args.push_oop(pts()); 2484 JavaValue result(T_OBJECT); 2485 JavaCalls::call_static(&result, 2486 SystemDictionary::MethodHandleNatives_klass(), 2487 vmSymbols::findMethodHandleType_name(), 2488 vmSymbols::findMethodHandleType_signature(), 2489 &args, CHECK_(empty)); 2490 Handle method_type(THREAD, (oop) result.get_jobject()); 2491 2492 if (can_be_cached) { 2493 // We can cache this MethodType inside the JVM. 2494 MutexLocker ml(SystemDictionary_lock, THREAD); 2495 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2496 if (spe == NULL) 2497 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2498 if (spe->method_type() == NULL) { 2499 spe->set_method_type(method_type()); 2500 } 2501 } 2502 2503 // report back to the caller with the MethodType 2504 return method_type; 2505 } 2506 2507 // Ask Java code to find or construct a method handle constant. 2508 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2509 int ref_kind, //e.g., JVM_REF_invokeVirtual 2510 KlassHandle callee, 2511 Symbol* name_sym, 2512 Symbol* signature, 2513 TRAPS) { 2514 Handle empty; 2515 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2516 Handle type; 2517 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2518 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2519 } else if (caller.is_null()) { 2520 // This should not happen. JDK code should take care of that. 2521 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2522 } else { 2523 ResourceMark rm(THREAD); 2524 SignatureStream ss(signature, false); 2525 if (!ss.is_done()) { 2526 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2527 SignatureStream::NCDFError, CHECK_(empty)); 2528 type = Handle(THREAD, mirror); 2529 ss.next(); 2530 if (!ss.is_done()) type = Handle(); // error! 2531 } 2532 } 2533 if (type.is_null()) { 2534 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2535 } 2536 2537 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2538 JavaCallArguments args; 2539 args.push_oop(caller->java_mirror()); // the referring class 2540 args.push_int(ref_kind); 2541 args.push_oop(callee->java_mirror()); // the target class 2542 args.push_oop(name()); 2543 args.push_oop(type()); 2544 JavaValue result(T_OBJECT); 2545 JavaCalls::call_static(&result, 2546 SystemDictionary::MethodHandleNatives_klass(), 2547 vmSymbols::linkMethodHandleConstant_name(), 2548 vmSymbols::linkMethodHandleConstant_signature(), 2549 &args, CHECK_(empty)); 2550 return Handle(THREAD, (oop) result.get_jobject()); 2551 } 2552 2553 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2554 // name and signature, as interpreted relative to the given class loader. 2555 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2556 Handle bootstrap_specifier, 2557 Symbol* name, 2558 Symbol* type, 2559 Handle *appendix_result, 2560 Handle *method_type_result, 2561 TRAPS) { 2562 methodHandle empty; 2563 Handle bsm, info; 2564 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2565 bsm = bootstrap_specifier; 2566 } else { 2567 assert(bootstrap_specifier->is_objArray(), ""); 2568 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2569 int len = args->length(); 2570 assert(len >= 1, ""); 2571 bsm = Handle(THREAD, args->obj_at(0)); 2572 if (len > 1) { 2573 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2574 for (int i = 1; i < len; i++) 2575 args1->obj_at_put(i-1, args->obj_at(i)); 2576 info = Handle(THREAD, args1); 2577 } 2578 } 2579 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2580 "caller must supply a valid BSM"); 2581 2582 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2583 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2584 2585 // This should not happen. JDK code should take care of that. 2586 if (caller.is_null() || method_type.is_null()) { 2587 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2588 } 2589 2590 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2591 assert(appendix_box->obj_at(0) == NULL, ""); 2592 2593 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2594 JavaCallArguments args; 2595 args.push_oop(caller->java_mirror()); 2596 args.push_oop(bsm()); 2597 args.push_oop(method_name()); 2598 args.push_oop(method_type()); 2599 args.push_oop(info()); 2600 args.push_oop(appendix_box); 2601 JavaValue result(T_OBJECT); 2602 JavaCalls::call_static(&result, 2603 SystemDictionary::MethodHandleNatives_klass(), 2604 vmSymbols::linkCallSite_name(), 2605 vmSymbols::linkCallSite_signature(), 2606 &args, CHECK_(empty)); 2607 Handle mname(THREAD, (oop) result.get_jobject()); 2608 (*method_type_result) = method_type; 2609 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2610 } 2611 2612 // Since the identity hash code for symbols changes when the symbols are 2613 // moved from the regular perm gen (hash in the mark word) to the shared 2614 // spaces (hash is the address), the classes loaded into the dictionary 2615 // may be in the wrong buckets. 2616 2617 void SystemDictionary::reorder_dictionary() { 2618 dictionary()->reorder_dictionary(); 2619 } 2620 2621 2622 void SystemDictionary::copy_buckets(char** top, char* end) { 2623 dictionary()->copy_buckets(top, end); 2624 } 2625 2626 2627 void SystemDictionary::copy_table(char** top, char* end) { 2628 dictionary()->copy_table(top, end); 2629 } 2630 2631 2632 void SystemDictionary::reverse() { 2633 dictionary()->reverse(); 2634 } 2635 2636 int SystemDictionary::number_of_classes() { 2637 return dictionary()->number_of_entries(); 2638 } 2639 2640 2641 // ---------------------------------------------------------------------------- 2642 void SystemDictionary::print_shared(bool details) { 2643 shared_dictionary()->print(details); 2644 } 2645 2646 void SystemDictionary::print(bool details) { 2647 dictionary()->print(details); 2648 2649 // Placeholders 2650 GCMutexLocker mu(SystemDictionary_lock); 2651 placeholders()->print(); 2652 2653 // loader constraints - print under SD_lock 2654 constraints()->print(); 2655 } 2656 2657 2658 void SystemDictionary::verify() { 2659 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2660 guarantee(constraints() != NULL, 2661 "Verify of loader constraints failed"); 2662 guarantee(dictionary()->number_of_entries() >= 0 && 2663 placeholders()->number_of_entries() >= 0, 2664 "Verify of system dictionary failed"); 2665 2666 // Verify dictionary 2667 dictionary()->verify(); 2668 2669 GCMutexLocker mu(SystemDictionary_lock); 2670 placeholders()->verify(); 2671 2672 // Verify constraint table 2673 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2674 constraints()->verify(dictionary(), placeholders()); 2675 } 2676 2677 // utility function for class load event 2678 void SystemDictionary::post_class_load_event(const Ticks& start_time, 2679 instanceKlassHandle k, 2680 Handle initiating_loader) { 2681 #if INCLUDE_TRACE 2682 EventClassLoad event(UNTIMED); 2683 if (event.should_commit()) { 2684 event.set_starttime(start_time); 2685 event.set_loadedClass(k()); 2686 oop defining_class_loader = k->class_loader(); 2687 event.set_definingClassLoader(defining_class_loader != NULL ? 2688 defining_class_loader->klass() : (Klass*)NULL); 2689 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader(); 2690 event.set_initiatingClassLoader(class_loader != NULL ? 2691 class_loader->klass() : (Klass*)NULL); 2692 event.commit(); 2693 } 2694 #endif // INCLUDE_TRACE 2695 } 2696 2697 #ifndef PRODUCT 2698 2699 // statistics code 2700 class ClassStatistics: AllStatic { 2701 private: 2702 static int nclasses; // number of classes 2703 static int nmethods; // number of methods 2704 static int nmethoddata; // number of methodData 2705 static int class_size; // size of class objects in words 2706 static int method_size; // size of method objects in words 2707 static int debug_size; // size of debug info in methods 2708 static int methoddata_size; // size of methodData objects in words 2709 2710 static void do_class(Klass* k) { 2711 nclasses++; 2712 class_size += k->size(); 2713 if (k->oop_is_instance()) { 2714 InstanceKlass* ik = (InstanceKlass*)k; 2715 class_size += ik->methods()->size(); 2716 class_size += ik->constants()->size(); 2717 class_size += ik->local_interfaces()->size(); 2718 class_size += ik->transitive_interfaces()->size(); 2719 // We do not have to count implementors, since we only store one! 2720 // SSS: How should these be accounted now that they have moved? 2721 // class_size += ik->fields()->length(); 2722 } 2723 } 2724 2725 static void do_method(Method* m) { 2726 nmethods++; 2727 method_size += m->size(); 2728 // class loader uses same objArray for empty vectors, so don't count these 2729 if (m->has_stackmap_table()) { 2730 method_size += m->stackmap_data()->size(); 2731 } 2732 2733 MethodData* mdo = m->method_data(); 2734 if (mdo != NULL) { 2735 nmethoddata++; 2736 methoddata_size += mdo->size(); 2737 } 2738 } 2739 2740 public: 2741 static void print() { 2742 SystemDictionary::classes_do(do_class); 2743 SystemDictionary::methods_do(do_method); 2744 tty->print_cr("Class statistics:"); 2745 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); 2746 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, 2747 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); 2748 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); 2749 } 2750 }; 2751 2752 2753 int ClassStatistics::nclasses = 0; 2754 int ClassStatistics::nmethods = 0; 2755 int ClassStatistics::nmethoddata = 0; 2756 int ClassStatistics::class_size = 0; 2757 int ClassStatistics::method_size = 0; 2758 int ClassStatistics::debug_size = 0; 2759 int ClassStatistics::methoddata_size = 0; 2760 2761 void SystemDictionary::print_class_statistics() { 2762 ResourceMark rm; 2763 ClassStatistics::print(); 2764 } 2765 2766 2767 class MethodStatistics: AllStatic { 2768 public: 2769 enum { 2770 max_parameter_size = 10 2771 }; 2772 private: 2773 2774 static int _number_of_methods; 2775 static int _number_of_final_methods; 2776 static int _number_of_static_methods; 2777 static int _number_of_native_methods; 2778 static int _number_of_synchronized_methods; 2779 static int _number_of_profiled_methods; 2780 static int _number_of_bytecodes; 2781 static int _parameter_size_profile[max_parameter_size]; 2782 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; 2783 2784 static void initialize() { 2785 _number_of_methods = 0; 2786 _number_of_final_methods = 0; 2787 _number_of_static_methods = 0; 2788 _number_of_native_methods = 0; 2789 _number_of_synchronized_methods = 0; 2790 _number_of_profiled_methods = 0; 2791 _number_of_bytecodes = 0; 2792 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; 2793 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; 2794 }; 2795 2796 static void do_method(Method* m) { 2797 _number_of_methods++; 2798 // collect flag info 2799 if (m->is_final() ) _number_of_final_methods++; 2800 if (m->is_static() ) _number_of_static_methods++; 2801 if (m->is_native() ) _number_of_native_methods++; 2802 if (m->is_synchronized()) _number_of_synchronized_methods++; 2803 if (m->method_data() != NULL) _number_of_profiled_methods++; 2804 // collect parameter size info (add one for receiver, if any) 2805 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; 2806 // collect bytecodes info 2807 { 2808 Thread *thread = Thread::current(); 2809 HandleMark hm(thread); 2810 BytecodeStream s(methodHandle(thread, m)); 2811 Bytecodes::Code c; 2812 while ((c = s.next()) >= 0) { 2813 _number_of_bytecodes++; 2814 _bytecodes_profile[c]++; 2815 } 2816 } 2817 } 2818 2819 public: 2820 static void print() { 2821 initialize(); 2822 SystemDictionary::methods_do(do_method); 2823 // generate output 2824 tty->cr(); 2825 tty->print_cr("Method statistics (static):"); 2826 // flag distribution 2827 tty->cr(); 2828 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); 2829 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); 2830 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); 2831 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); 2832 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); 2833 // parameter size profile 2834 tty->cr(); 2835 { int tot = 0; 2836 int avg = 0; 2837 for (int i = 0; i < max_parameter_size; i++) { 2838 int n = _parameter_size_profile[i]; 2839 tot += n; 2840 avg += n*i; 2841 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); 2842 } 2843 assert(tot == _number_of_methods, "should be the same"); 2844 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); 2845 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); 2846 } 2847 // bytecodes profile 2848 tty->cr(); 2849 { int tot = 0; 2850 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { 2851 if (Bytecodes::is_defined(i)) { 2852 Bytecodes::Code c = Bytecodes::cast(i); 2853 int n = _bytecodes_profile[c]; 2854 tot += n; 2855 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); 2856 } 2857 } 2858 assert(tot == _number_of_bytecodes, "should be the same"); 2859 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); 2860 } 2861 tty->cr(); 2862 } 2863 }; 2864 2865 int MethodStatistics::_number_of_methods; 2866 int MethodStatistics::_number_of_final_methods; 2867 int MethodStatistics::_number_of_static_methods; 2868 int MethodStatistics::_number_of_native_methods; 2869 int MethodStatistics::_number_of_synchronized_methods; 2870 int MethodStatistics::_number_of_profiled_methods; 2871 int MethodStatistics::_number_of_bytecodes; 2872 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; 2873 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; 2874 2875 2876 void SystemDictionary::print_method_statistics() { 2877 MethodStatistics::print(); 2878 } 2879 2880 #endif // PRODUCT