systemDictionary.cpp revision 0:a61af66fc99e
1/* 2 * Copyright 1997-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25# include "incls/_precompiled.incl" 26# include "incls/_systemDictionary.cpp.incl" 27 28 29Dictionary* SystemDictionary::_dictionary = NULL; 30PlaceholderTable* SystemDictionary::_placeholders = NULL; 31Dictionary* SystemDictionary::_shared_dictionary = NULL; 32LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 33ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 34 35 36int SystemDictionary::_number_of_modifications = 0; 37 38oop SystemDictionary::_system_loader_lock_obj = NULL; 39 40klassOop SystemDictionary::_object_klass = NULL; 41klassOop SystemDictionary::_string_klass = NULL; 42klassOop SystemDictionary::_class_klass = NULL; 43klassOop SystemDictionary::_cloneable_klass = NULL; 44klassOop SystemDictionary::_classloader_klass = NULL; 45klassOop SystemDictionary::_serializable_klass = NULL; 46klassOop SystemDictionary::_system_klass = NULL; 47 48klassOop SystemDictionary::_throwable_klass = NULL; 49klassOop SystemDictionary::_error_klass = NULL; 50klassOop SystemDictionary::_threaddeath_klass = NULL; 51klassOop SystemDictionary::_exception_klass = NULL; 52klassOop SystemDictionary::_runtime_exception_klass = NULL; 53klassOop SystemDictionary::_classNotFoundException_klass = NULL; 54klassOop SystemDictionary::_noClassDefFoundError_klass = NULL; 55klassOop SystemDictionary::_linkageError_klass = NULL; 56klassOop SystemDictionary::_classCastException_klass = NULL; 57klassOop SystemDictionary::_arrayStoreException_klass = NULL; 58klassOop SystemDictionary::_virtualMachineError_klass = NULL; 59klassOop SystemDictionary::_outOfMemoryError_klass = NULL; 60klassOop SystemDictionary::_StackOverflowError_klass = NULL; 61klassOop SystemDictionary::_illegalMonitorStateException_klass = NULL; 62klassOop SystemDictionary::_protectionDomain_klass = NULL; 63klassOop SystemDictionary::_AccessControlContext_klass = NULL; 64 65klassOop SystemDictionary::_reference_klass = NULL; 66klassOop SystemDictionary::_soft_reference_klass = NULL; 67klassOop SystemDictionary::_weak_reference_klass = NULL; 68klassOop SystemDictionary::_final_reference_klass = NULL; 69klassOop SystemDictionary::_phantom_reference_klass = NULL; 70klassOop SystemDictionary::_finalizer_klass = NULL; 71 72klassOop SystemDictionary::_thread_klass = NULL; 73klassOop SystemDictionary::_threadGroup_klass = NULL; 74klassOop SystemDictionary::_properties_klass = NULL; 75klassOop SystemDictionary::_reflect_accessible_object_klass = NULL; 76klassOop SystemDictionary::_reflect_field_klass = NULL; 77klassOop SystemDictionary::_reflect_method_klass = NULL; 78klassOop SystemDictionary::_reflect_constructor_klass = NULL; 79klassOop SystemDictionary::_reflect_magic_klass = NULL; 80klassOop SystemDictionary::_reflect_method_accessor_klass = NULL; 81klassOop SystemDictionary::_reflect_constructor_accessor_klass = NULL; 82klassOop SystemDictionary::_reflect_delegating_classloader_klass = NULL; 83klassOop SystemDictionary::_reflect_constant_pool_klass = NULL; 84klassOop SystemDictionary::_reflect_unsafe_static_field_accessor_impl_klass = NULL; 85 86klassOop SystemDictionary::_vector_klass = NULL; 87klassOop SystemDictionary::_hashtable_klass = NULL; 88klassOop SystemDictionary::_stringBuffer_klass = NULL; 89 90klassOop SystemDictionary::_stackTraceElement_klass = NULL; 91 92klassOop SystemDictionary::_java_nio_Buffer_klass = NULL; 93 94klassOop SystemDictionary::_sun_misc_AtomicLongCSImpl_klass = NULL; 95klassOop SystemDictionary::_sun_jkernel_DownloadManager_klass = NULL; 96 97klassOop SystemDictionary::_boolean_klass = NULL; 98klassOop SystemDictionary::_char_klass = NULL; 99klassOop SystemDictionary::_float_klass = NULL; 100klassOop SystemDictionary::_double_klass = NULL; 101klassOop SystemDictionary::_byte_klass = NULL; 102klassOop SystemDictionary::_short_klass = NULL; 103klassOop SystemDictionary::_int_klass = NULL; 104klassOop SystemDictionary::_long_klass = NULL; 105klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 106 107oop SystemDictionary::_java_system_loader = NULL; 108 109bool SystemDictionary::_has_loadClassInternal = false; 110bool SystemDictionary::_has_checkPackageAccess = false; 111 112// lazily initialized klass variables 113volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 114 115 116// ---------------------------------------------------------------------------- 117// Java-level SystemLoader 118 119oop SystemDictionary::java_system_loader() { 120 return _java_system_loader; 121} 122 123void SystemDictionary::compute_java_system_loader(TRAPS) { 124 KlassHandle system_klass(THREAD, _classloader_klass); 125 JavaValue result(T_OBJECT); 126 JavaCalls::call_static(&result, 127 KlassHandle(THREAD, _classloader_klass), 128 vmSymbolHandles::getSystemClassLoader_name(), 129 vmSymbolHandles::void_classloader_signature(), 130 CHECK); 131 132 _java_system_loader = (oop)result.get_jobject(); 133} 134 135 136// ---------------------------------------------------------------------------- 137// debugging 138 139#ifdef ASSERT 140 141// return true if class_name contains no '.' (internal format is '/') 142bool SystemDictionary::is_internal_format(symbolHandle class_name) { 143 if (class_name.not_null()) { 144 ResourceMark rm; 145 char* name = class_name->as_C_string(); 146 return strchr(name, '.') == NULL; 147 } else { 148 return true; 149 } 150} 151 152#endif 153 154// ---------------------------------------------------------------------------- 155// Resolving of classes 156 157// Forwards to resolve_or_null 158 159klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 160 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 161 if (HAS_PENDING_EXCEPTION || klass == NULL) { 162 KlassHandle k_h(THREAD, klass); 163 // can return a null klass 164 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); 165 } 166 return klass; 167} 168 169klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) { 170 if (HAS_PENDING_EXCEPTION) { 171 // If we have a pending exception we forward it to the caller, unless throw_error is true, 172 // in which case we have to check whether the pending exception is a ClassNotFoundException, 173 // and if so convert it to a NoClassDefFoundError 174 // And chain the original ClassNotFoundException 175 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) { 176 ResourceMark rm(THREAD); 177 assert(klass_h() == NULL, "Should not have result with exception pending"); 178 Handle e(THREAD, PENDING_EXCEPTION); 179 CLEAR_PENDING_EXCEPTION; 180 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 181 } else { 182 return NULL; 183 } 184 } 185 // Class not found, throw appropriate error or exception depending on value of throw_error 186 if (klass_h() == NULL) { 187 ResourceMark rm(THREAD); 188 if (throw_error) { 189 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 190 } else { 191 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 192 } 193 } 194 return (klassOop)klass_h(); 195} 196 197 198klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, 199 bool throw_error, TRAPS) 200{ 201 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 202} 203 204 205// Forwards to resolve_instance_class_or_null 206 207klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { 208 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread"); 209 if (FieldType::is_array(class_name())) { 210 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 211 } else { 212 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 213 } 214} 215 216klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) { 217 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 218} 219 220// Forwards to resolve_instance_class_or_null 221 222klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name, 223 Handle class_loader, 224 Handle protection_domain, 225 TRAPS) { 226 assert(FieldType::is_array(class_name()), "must be array"); 227 jint dimension; 228 symbolOop object_key; 229 klassOop k = NULL; 230 // dimension and object_key are assigned as a side-effect of this call 231 BasicType t = FieldType::get_array_info(class_name(), 232 &dimension, 233 &object_key, 234 CHECK_NULL); 235 236 if (t == T_OBJECT) { 237 symbolHandle h_key(THREAD, object_key); 238 // naked oop "k" is OK here -- we assign back into it 239 k = SystemDictionary::resolve_instance_class_or_null(h_key, 240 class_loader, 241 protection_domain, 242 CHECK_NULL); 243 if (k != NULL) { 244 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL); 245 } 246 } else { 247 k = Universe::typeArrayKlassObj(t); 248 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL); 249 } 250 return k; 251} 252 253 254// Must be called for any super-class or super-interface resolution 255// during class definition to allow class circularity checking 256// super-interface callers: 257// parse_interfaces - for defineClass & jvmtiRedefineClasses 258// super-class callers: 259// ClassFileParser - for defineClass & jvmtiRedefineClasses 260// load_shared_class - while loading a class from shared archive 261// resolve_instance_class_or_fail: 262// when resolving a class that has an existing placeholder with 263// a saved superclass [i.e. a defineClass is currently in progress] 264// if another thread is trying to resolve the class, it must do 265// super-class checks on its own thread to catch class circularity 266// This last call is critical in class circularity checking for cases 267// where classloading is delegated to different threads and the 268// classloader lock is released. 269// Take the case: Base->Super->Base 270// 1. If thread T1 tries to do a defineClass of class Base 271// resolve_super_or_fail creates placeholder: T1, Base (super Super) 272// 2. resolve_instance_class_or_null does not find SD or placeholder for Super 273// so it tries to load Super 274// 3. If we load the class internally, or user classloader uses same thread 275// loadClassFromxxx or defineClass via parseClassFile Super ... 276// 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 277// 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 278// 3.4 calls resolve_super_or_fail Base 279// 3.5 finds T1,Base -> throws class circularity 280//OR 4. If T2 tries to resolve Super via defineClass Super ... 281// 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 282// 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 283// 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 284// 4.4 finds T2, Super -> throws class circularity 285// Must be called, even if superclass is null, since this is 286// where the placeholder entry is created which claims this 287// thread is loading this class/classloader. 288klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name, 289 symbolHandle class_name, 290 Handle class_loader, 291 Handle protection_domain, 292 bool is_superclass, 293 TRAPS) { 294 295 // Double-check, if child class is already loaded, just return super-class,interface 296 // Don't add a placedholder if already loaded, i.e. already in system dictionary 297 // Make sure there's a placeholder for the *child* before resolving. 298 // Used as a claim that this thread is currently loading superclass/classloader 299 // Used here for ClassCircularity checks and also for heap verification 300 // (every instanceKlass in the heap needs to be in the system dictionary 301 // or have a placeholder). 302 // Must check ClassCircularity before checking if super class is already loaded 303 // 304 // We might not already have a placeholder if this child_name was 305 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 306 // the name of the class might not be known until the stream is actually 307 // parsed. 308 // Bugs 4643874, 4715493 309 // compute_hash can have a safepoint 310 311 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader); 312 int d_index = dictionary()->hash_to_index(d_hash); 313 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader); 314 int p_index = placeholders()->hash_to_index(p_hash); 315 // can't throw error holding a lock 316 bool child_already_loaded = false; 317 bool throw_circularity_error = false; 318 { 319 MutexLocker mu(SystemDictionary_lock, THREAD); 320 klassOop childk = find_class(d_index, d_hash, child_name, class_loader); 321 klassOop quicksuperk; 322 // to support // loading: if child done loading, just return superclass 323 // if class_name, & class_loader don't match: 324 // if initial define, SD update will give LinkageError 325 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 326 // so we don't throw an exception here. 327 // see: nsk redefclass014 & java.lang.instrument Instrument032 328 if ((childk != NULL ) && (is_superclass) && 329 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) && 330 331 ((Klass::cast(quicksuperk)->name() == class_name()) && 332 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) { 333 return quicksuperk; 334 } else { 335 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); 336 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 337 throw_circularity_error = true; 338 } 339 340 // add placeholder entry even if error - callers will remove on error 341 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 342 if (throw_circularity_error) { 343 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER); 344 } 345 } 346 } 347 if (throw_circularity_error) { 348 ResourceMark rm(THREAD); 349 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 350 } 351 352// java.lang.Object should have been found above 353 assert(class_name() != NULL, "null super class for resolving"); 354 // Resolve the super class or interface, check results on return 355 klassOop superk = NULL; 356 superk = SystemDictionary::resolve_or_null(class_name, 357 class_loader, 358 protection_domain, 359 THREAD); 360 361 KlassHandle superk_h(THREAD, superk); 362 363 // Note: clean up of placeholders currently in callers of 364 // resolve_super_or_fail - either at update_dictionary time 365 // or on error 366 { 367 MutexLocker mu(SystemDictionary_lock, THREAD); 368 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); 369 if (probe != NULL) { 370 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER); 371 } 372 } 373 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 374 // can null superk 375 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); 376 } 377 378 return superk_h(); 379} 380 381 382void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 383 Handle class_loader, 384 Handle protection_domain, 385 TRAPS) { 386 if(!has_checkPackageAccess()) return; 387 388 // Now we have to call back to java to check if the initating class has access 389 JavaValue result(T_VOID); 390 if (TraceProtectionDomainVerification) { 391 // Print out trace information 392 tty->print_cr("Checking package access"); 393 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); 394 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); 395 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); 396 } 397 398 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader"); 399 400 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass()); 401 JavaCalls::call_special(&result, 402 class_loader, 403 system_loader, 404 vmSymbolHandles::checkPackageAccess_name(), 405 vmSymbolHandles::class_protectiondomain_signature(), 406 Handle(THREAD, klass->java_mirror()), 407 protection_domain, 408 THREAD); 409 410 if (TraceProtectionDomainVerification) { 411 if (HAS_PENDING_EXCEPTION) { 412 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); 413 } else { 414 tty->print_cr(" -> granted"); 415 } 416 tty->cr(); 417 } 418 419 if (HAS_PENDING_EXCEPTION) return; 420 421 // If no exception has been thrown, we have validated the protection domain 422 // Insert the protection domain of the initiating class into the set. 423 { 424 // We recalculate the entry here -- we've called out to java since 425 // the last time it was calculated. 426 symbolHandle kn(THREAD, klass->name()); 427 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader); 428 int d_index = dictionary()->hash_to_index(d_hash); 429 430 MutexLocker mu(SystemDictionary_lock, THREAD); 431 { 432 // Note that we have an entry, and entries can be deleted only during GC, 433 // so we cannot allow GC to occur while we're holding this entry. 434 435 // We're using a No_Safepoint_Verifier to catch any place where we 436 // might potentially do a GC at all. 437 // SystemDictionary::do_unloading() asserts that classes are only 438 // unloaded at a safepoint. 439 No_Safepoint_Verifier nosafepoint; 440 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader, 441 protection_domain, THREAD); 442 } 443 } 444} 445 446// We only get here if this thread finds that another thread 447// has already claimed the placeholder token for the current operation, 448// but that other thread either never owned or gave up the 449// object lock 450// Waits on SystemDictionary_lock to indicate placeholder table updated 451// On return, caller must recheck placeholder table state 452// 453// We only get here if 454// 1) custom classLoader, i.e. not bootstrap classloader 455// 2) UnsyncloadClass not set 456// 3) custom classLoader has broken the class loader objectLock 457// so another thread got here in parallel 458// 459// lockObject must be held. 460// Complicated dance due to lock ordering: 461// Must first release the classloader object lock to 462// allow initial definer to complete the class definition 463// and to avoid deadlock 464// Reclaim classloader lock object with same original recursion count 465// Must release SystemDictionary_lock after notify, since 466// class loader lock must be claimed before SystemDictionary_lock 467// to prevent deadlocks 468// 469// The notify allows applications that did an untimed wait() on 470// the classloader object lock to not hang. 471void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 472 assert_lock_strong(SystemDictionary_lock); 473 474 bool calledholdinglock 475 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 476 assert(calledholdinglock,"must hold lock for notify"); 477 assert(!UnsyncloadClass, "unexpected double_lock_wait"); 478 ObjectSynchronizer::notifyall(lockObject, THREAD); 479 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 480 SystemDictionary_lock->wait(); 481 SystemDictionary_lock->unlock(); 482 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 483 SystemDictionary_lock->lock(); 484} 485 486// If the class in is in the placeholder table, class loading is in progress 487// For cases where the application changes threads to load classes, it 488// is critical to ClassCircularity detection that we try loading 489// the superclass on the same thread internally, so we do parallel 490// super class loading here. 491// This also is critical in cases where the original thread gets stalled 492// even in non-circularity situations. 493// Note: only one thread can define the class, but multiple can resolve 494// Note: must call resolve_super_or_fail even if null super - 495// to force placeholder entry creation for this class 496// Caller must check for pending exception 497// Returns non-null klassOop if other thread has completed load 498// and we are done, 499// If return null klassOop and no pending exception, the caller must load the class 500instanceKlassHandle SystemDictionary::handle_parallel_super_load( 501 symbolHandle name, symbolHandle superclassname, Handle class_loader, 502 Handle protection_domain, Handle lockObject, TRAPS) { 503 504 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 505 unsigned int d_hash = dictionary()->compute_hash(name, class_loader); 506 int d_index = dictionary()->hash_to_index(d_hash); 507 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); 508 int p_index = placeholders()->hash_to_index(p_hash); 509 510 // superk is not used, resolve_super called for circularity check only 511 // This code is reached in two situations. One if this thread 512 // is loading the same class twice (e.g. ClassCircularity, or 513 // java.lang.instrument). 514 // The second is if another thread started the resolve_super first 515 // and has not yet finished. 516 // In both cases the original caller will clean up the placeholder 517 // entry on error. 518 klassOop superk = SystemDictionary::resolve_super_or_fail(name, 519 superclassname, 520 class_loader, 521 protection_domain, 522 true, 523 CHECK_(nh)); 524 // We don't redefine the class, so we just need to clean up if there 525 // was not an error (don't want to modify any system dictionary 526 // data structures). 527 { 528 MutexLocker mu(SystemDictionary_lock, THREAD); 529 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); 530 SystemDictionary_lock->notify_all(); 531 } 532 533 // UnsyncloadClass does NOT wait for parallel superclass loads to complete 534 // Bootstrap classloader does wait for parallel superclass loads 535 if (UnsyncloadClass) { 536 MutexLocker mu(SystemDictionary_lock, THREAD); 537 // Check if classloading completed while we were loading superclass or waiting 538 klassOop check = find_class(d_index, d_hash, name, class_loader); 539 if (check != NULL) { 540 // Klass is already loaded, so just return it 541 return(instanceKlassHandle(THREAD, check)); 542 } else { 543 return nh; 544 } 545 } 546 547 // must loop to both handle other placeholder updates 548 // and spurious notifications 549 bool super_load_in_progress = true; 550 PlaceholderEntry* placeholder; 551 while (super_load_in_progress) { 552 MutexLocker mu(SystemDictionary_lock, THREAD); 553 // Check if classloading completed while we were loading superclass or waiting 554 klassOop check = find_class(d_index, d_hash, name, class_loader); 555 if (check != NULL) { 556 // Klass is already loaded, so just return it 557 return(instanceKlassHandle(THREAD, check)); 558 } else { 559 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); 560 if (placeholder && placeholder->super_load_in_progress() ){ 561 // Before UnsyncloadClass: 562 // We only get here if the application has released the 563 // classloader lock when another thread was in the middle of loading a 564 // superclass/superinterface for this class, and now 565 // this thread is also trying to load this class. 566 // To minimize surprises, the first thread that started to 567 // load a class should be the one to complete the loading 568 // with the classfile it initially expected. 569 // This logic has the current thread wait once it has done 570 // all the superclass/superinterface loading it can, until 571 // the original thread completes the class loading or fails 572 // If it completes we will use the resulting instanceKlass 573 // which we will find below in the systemDictionary. 574 // We also get here for parallel bootstrap classloader 575 if (class_loader.is_null()) { 576 SystemDictionary_lock->wait(); 577 } else { 578 double_lock_wait(lockObject, THREAD); 579 } 580 } else { 581 // If not in SD and not in PH, other thread's load must have failed 582 super_load_in_progress = false; 583 } 584 } 585 } 586 return (nh); 587} 588 589 590klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { 591 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name"); 592 // First check to see if we should remove wrapping L and ; 593 symbolHandle name; 594 if (FieldType::is_obj(class_name())) { 595 ResourceMark rm(THREAD); 596 // Ignore wrapping L and ;. 597 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL); 598 } else { 599 name = class_name; 600 } 601 602 // UseNewReflection 603 // Fix for 4474172; see evaluation for more details 604 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 605 606 // Do lookup to see if class already exist and the protection domain 607 // has the right access 608 unsigned int d_hash = dictionary()->compute_hash(name, class_loader); 609 int d_index = dictionary()->hash_to_index(d_hash); 610 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader, 611 protection_domain, THREAD); 612 if (probe != NULL) return probe; 613 614 615 // Non-bootstrap class loaders will call out to class loader and 616 // define via jvm/jni_DefineClass which will acquire the 617 // class loader object lock to protect against multiple threads 618 // defining the class in parallel by accident. 619 // This lock must be acquired here so the waiter will find 620 // any successful result in the SystemDictionary and not attempt 621 // the define 622 // Classloaders that support parallelism, e.g. bootstrap classloader, 623 // or all classloaders with UnsyncloadClass do not acquire lock here 624 bool DoObjectLock = true; 625 if (UnsyncloadClass || (class_loader.is_null())) { 626 DoObjectLock = false; 627 } 628 629 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); 630 int p_index = placeholders()->hash_to_index(p_hash); 631 632 // Class is not in SystemDictionary so we have to do loading. 633 // Make sure we are synchronized on the class loader before we proceed 634 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 635 check_loader_lock_contention(lockObject, THREAD); 636 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 637 638 // Check again (after locking) if class already exist in SystemDictionary 639 bool class_has_been_loaded = false; 640 bool super_load_in_progress = false; 641 bool havesupername = false; 642 instanceKlassHandle k; 643 PlaceholderEntry* placeholder; 644 symbolHandle superclassname; 645 646 { 647 MutexLocker mu(SystemDictionary_lock, THREAD); 648 klassOop check = find_class(d_index, d_hash, name, class_loader); 649 if (check != NULL) { 650 // Klass is already loaded, so just return it 651 class_has_been_loaded = true; 652 k = instanceKlassHandle(THREAD, check); 653 } else { 654 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); 655 if (placeholder && placeholder->super_load_in_progress()) { 656 super_load_in_progress = true; 657 if (placeholder->havesupername() == true) { 658 superclassname = symbolHandle(THREAD, placeholder->supername()); 659 havesupername = true; 660 } 661 } 662 } 663 } 664 665 // If the class in is in the placeholder table, class loading is in progress 666 if (super_load_in_progress && havesupername==true) { 667 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 668 class_loader, protection_domain, lockObject, THREAD); 669 if (HAS_PENDING_EXCEPTION) { 670 return NULL; 671 } 672 if (!k.is_null()) { 673 class_has_been_loaded = true; 674 } 675 } 676 677 if (!class_has_been_loaded) { 678 679 // add placeholder entry to record loading instance class 680 // Five cases: 681 // All cases need to prevent modifying bootclasssearchpath 682 // in parallel with a classload of same classname 683 // case 1. traditional classloaders that rely on the classloader object lock 684 // - no other need for LOAD_INSTANCE 685 // case 2. traditional classloaders that break the classloader object lock 686 // as a deadlock workaround. Detection of this case requires that 687 // this check is done while holding the classloader object lock, 688 // and that lock is still held when calling classloader's loadClass. 689 // For these classloaders, we ensure that the first requestor 690 // completes the load and other requestors wait for completion. 691 // case 3. UnsyncloadClass - don't use objectLocker 692 // With this flag, we allow parallel classloading of a 693 // class/classloader pair 694 // case4. Bootstrap classloader - don't own objectLocker 695 // This classloader supports parallelism at the classloader level, 696 // but only allows a single load of a class/classloader pair. 697 // No performance benefit and no deadlock issues. 698 // case 5. Future: parallel user level classloaders - without objectLocker 699 symbolHandle nullsymbolHandle; 700 bool throw_circularity_error = false; 701 { 702 MutexLocker mu(SystemDictionary_lock, THREAD); 703 if (!UnsyncloadClass) { 704 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); 705 if (oldprobe) { 706 // only need check_seen_thread once, not on each loop 707 // 6341374 java/lang/Instrument with -Xcomp 708 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 709 throw_circularity_error = true; 710 } else { 711 // case 1: traditional: should never see load_in_progress. 712 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 713 714 // case 4: bootstrap classloader: prevent futile classloading, 715 // wait on first requestor 716 if (class_loader.is_null()) { 717 SystemDictionary_lock->wait(); 718 } else { 719 // case 2: traditional with broken classloader lock. wait on first 720 // requestor. 721 double_lock_wait(lockObject, THREAD); 722 } 723 // Check if classloading completed while we were waiting 724 klassOop check = find_class(d_index, d_hash, name, class_loader); 725 if (check != NULL) { 726 // Klass is already loaded, so just return it 727 k = instanceKlassHandle(THREAD, check); 728 class_has_been_loaded = true; 729 } 730 // check if other thread failed to load and cleaned up 731 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); 732 } 733 } 734 } 735 } 736 // All cases: add LOAD_INSTANCE 737 // case 3: UnsyncloadClass: allow competing threads to try 738 // LOAD_INSTANCE in parallel 739 // add placeholder entry even if error - callers will remove on error 740 if (!class_has_been_loaded) { 741 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD); 742 if (throw_circularity_error) { 743 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); 744 } 745 // For class loaders that do not acquire the classloader object lock, 746 // if they did not catch another thread holding LOAD_INSTANCE, 747 // need a check analogous to the acquire ObjectLocker/find_class 748 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 749 // one final check if the load has already completed 750 klassOop check = find_class(d_index, d_hash, name, class_loader); 751 if (check != NULL) { 752 // Klass is already loaded, so just return it 753 k = instanceKlassHandle(THREAD, check); 754 class_has_been_loaded = true; 755 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); 756 } 757 } 758 } 759 // must throw error outside of owning lock 760 if (throw_circularity_error) { 761 ResourceMark rm(THREAD); 762 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 763 } 764 765 if (!class_has_been_loaded) { 766 767 // Do actual loading 768 k = load_instance_class(name, class_loader, THREAD); 769 770 // In custom class loaders, the usual findClass calls 771 // findLoadedClass, which directly searches the SystemDictionary, then 772 // defineClass. If these are not atomic with respect to other threads, 773 // the findLoadedClass can fail, but the defineClass can get a 774 // LinkageError:: duplicate class definition. 775 // If they got a linkageError, check if a parallel class load succeeded. 776 // If it did, then for bytecode resolution the specification requires 777 // that we return the same result we did for the other thread, i.e. the 778 // successfully loaded instanceKlass 779 // Note: Class can not be unloaded as long as any classloader refs exist 780 // Should not get here for classloaders that support parallelism 781 // with the new cleaner mechanism, e.g. bootstrap classloader 782 if (UnsyncloadClass || (class_loader.is_null())) { 783 if (k.is_null() && HAS_PENDING_EXCEPTION 784 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) { 785 MutexLocker mu(SystemDictionary_lock, THREAD); 786 klassOop check = find_class(d_index, d_hash, name, class_loader); 787 if (check != NULL) { 788 // Klass is already loaded, so just use it 789 k = instanceKlassHandle(THREAD, check); 790 CLEAR_PENDING_EXCEPTION; 791 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 792 } 793 } 794 } 795 796 // clean up placeholder entries for success or error 797 // This cleans up LOAD_INSTANCE entries 798 // It also cleans up LOAD_SUPER entries on errors from 799 // calling load_instance_class 800 { 801 MutexLocker mu(SystemDictionary_lock, THREAD); 802 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader); 803 if (probe != NULL) { 804 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); 805 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); 806 SystemDictionary_lock->notify_all(); 807 } 808 } 809 810 // If everything was OK (no exceptions, no null return value), and 811 // class_loader is NOT the defining loader, do a little more bookkeeping. 812 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 813 k->class_loader() != class_loader()) { 814 815 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 816 817 // Need to check for a PENDING_EXCEPTION again; check_constraints 818 // can throw and doesn't use the CHECK macro. 819 if (!HAS_PENDING_EXCEPTION) { 820 { // Grabbing the Compile_lock prevents systemDictionary updates 821 // during compilations. 822 MutexLocker mu(Compile_lock, THREAD); 823 update_dictionary(d_index, d_hash, p_index, p_hash, 824 k, class_loader, THREAD); 825 } 826 if (JvmtiExport::should_post_class_load()) { 827 Thread *thread = THREAD; 828 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 829 JvmtiExport::post_class_load((JavaThread *) thread, k()); 830 } 831 } 832 } 833 if (HAS_PENDING_EXCEPTION || k.is_null()) { 834 // On error, clean up placeholders 835 { 836 MutexLocker mu(SystemDictionary_lock, THREAD); 837 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); 838 SystemDictionary_lock->notify_all(); 839 } 840 return NULL; 841 } 842 } 843 } 844 845#ifdef ASSERT 846 { 847 Handle loader (THREAD, k->class_loader()); 848 MutexLocker mu(SystemDictionary_lock, THREAD); 849 oop kk = find_class_or_placeholder(name, loader); 850 assert(kk == k(), "should be present in dictionary"); 851 } 852#endif 853 854 // return if the protection domain in NULL 855 if (protection_domain() == NULL) return k(); 856 857 // Check the protection domain has the right access 858 { 859 MutexLocker mu(SystemDictionary_lock, THREAD); 860 // Note that we have an entry, and entries can be deleted only during GC, 861 // so we cannot allow GC to occur while we're holding this entry. 862 // We're using a No_Safepoint_Verifier to catch any place where we 863 // might potentially do a GC at all. 864 // SystemDictionary::do_unloading() asserts that classes are only 865 // unloaded at a safepoint. 866 No_Safepoint_Verifier nosafepoint; 867 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 868 class_loader, 869 protection_domain)) { 870 return k(); 871 } 872 } 873 874 // Verify protection domain. If it fails an exception is thrown 875 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL))); 876 877 return k(); 878} 879 880 881// This routine does not lock the system dictionary. 882// 883// Since readers don't hold a lock, we must make sure that system 884// dictionary entries are only removed at a safepoint (when only one 885// thread is running), and are added to in a safe way (all links must 886// be updated in an MT-safe manner). 887// 888// Callers should be aware that an entry could be added just after 889// _dictionary->bucket(index) is read here, so the caller will not see 890// the new entry. 891 892klassOop SystemDictionary::find(symbolHandle class_name, 893 Handle class_loader, 894 Handle protection_domain, 895 TRAPS) { 896 897 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); 898 int d_index = dictionary()->hash_to_index(d_hash); 899 900 { 901 // Note that we have an entry, and entries can be deleted only during GC, 902 // so we cannot allow GC to occur while we're holding this entry. 903 // We're using a No_Safepoint_Verifier to catch any place where we 904 // might potentially do a GC at all. 905 // SystemDictionary::do_unloading() asserts that classes are only 906 // unloaded at a safepoint. 907 No_Safepoint_Verifier nosafepoint; 908 return dictionary()->find(d_index, d_hash, class_name, class_loader, 909 protection_domain, THREAD); 910 } 911} 912 913 914// Look for a loaded instance or array klass by name. Do not do any loading. 915// return NULL in case of error. 916klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name, 917 Handle class_loader, 918 Handle protection_domain, 919 TRAPS) { 920 klassOop k = NULL; 921 assert(class_name() != NULL, "class name must be non NULL"); 922 if (FieldType::is_array(class_name())) { 923 // The name refers to an array. Parse the name. 924 jint dimension; 925 symbolOop object_key; 926 927 // dimension and object_key are assigned as a side-effect of this call 928 BasicType t = FieldType::get_array_info(class_name(), &dimension, 929 &object_key, CHECK_(NULL)); 930 if (t != T_OBJECT) { 931 k = Universe::typeArrayKlassObj(t); 932 } else { 933 symbolHandle h_key(THREAD, object_key); 934 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD); 935 } 936 if (k != NULL) { 937 k = Klass::cast(k)->array_klass_or_null(dimension); 938 } 939 } else { 940 k = find(class_name, class_loader, protection_domain, THREAD); 941 } 942 return k; 943} 944 945// Note: this method is much like resolve_from_stream, but 946// updates no supplemental data structures. 947// TODO consolidate the two methods with a helper routine? 948klassOop SystemDictionary::parse_stream(symbolHandle class_name, 949 Handle class_loader, 950 Handle protection_domain, 951 ClassFileStream* st, 952 TRAPS) { 953 symbolHandle parsed_name; 954 955 // Parse the stream. Note that we do this even though this klass might 956 // already be present in the SystemDictionary, otherwise we would not 957 // throw potential ClassFormatErrors. 958 // 959 // Note: "name" is updated. 960 // Further note: a placeholder will be added for this class when 961 // super classes are loaded (resolve_super_or_fail). We expect this 962 // to be called for all classes but java.lang.Object; and we preload 963 // java.lang.Object through resolve_or_fail, not this path. 964 965 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 966 class_loader, 967 protection_domain, 968 parsed_name, 969 THREAD); 970 971 972 // We don't redefine the class, so we just need to clean up whether there 973 // was an error or not (don't want to modify any system dictionary 974 // data structures). 975 // Parsed name could be null if we threw an error before we got far 976 // enough along to parse it -- in that case, there is nothing to clean up. 977 if (!parsed_name.is_null()) { 978 unsigned int p_hash = placeholders()->compute_hash(parsed_name, 979 class_loader); 980 int p_index = placeholders()->hash_to_index(p_hash); 981 { 982 MutexLocker mu(SystemDictionary_lock, THREAD); 983 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); 984 SystemDictionary_lock->notify_all(); 985 } 986 } 987 988 return k(); 989} 990 991// Add a klass to the system from a stream (called by jni_DefineClass and 992// JVM_DefineClass). 993// Note: class_name can be NULL. In that case we do not know the name of 994// the class until we have parsed the stream. 995 996klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name, 997 Handle class_loader, 998 Handle protection_domain, 999 ClassFileStream* st, 1000 TRAPS) { 1001 1002 // Make sure we are synchronized on the class loader before we initiate 1003 // loading. 1004 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1005 check_loader_lock_contention(lockObject, THREAD); 1006 ObjectLocker ol(lockObject, THREAD); 1007 1008 symbolHandle parsed_name; 1009 1010 // Parse the stream. Note that we do this even though this klass might 1011 // already be present in the SystemDictionary, otherwise we would not 1012 // throw potential ClassFormatErrors. 1013 // 1014 // Note: "name" is updated. 1015 // Further note: a placeholder will be added for this class when 1016 // super classes are loaded (resolve_super_or_fail). We expect this 1017 // to be called for all classes but java.lang.Object; and we preload 1018 // java.lang.Object through resolve_or_fail, not this path. 1019 1020 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1021 class_loader, 1022 protection_domain, 1023 parsed_name, 1024 THREAD); 1025 1026 const char* pkg = "java/"; 1027 if (!HAS_PENDING_EXCEPTION && 1028 !class_loader.is_null() && 1029 !parsed_name.is_null() && 1030 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1031 // It is illegal to define classes in the "java." package from 1032 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1033 ResourceMark rm(THREAD); 1034 char* name = parsed_name->as_C_string(); 1035 char* index = strrchr(name, '/'); 1036 *index = '\0'; // chop to just the package name 1037 while ((index = strchr(name, '/')) != NULL) { 1038 *index = '.'; // replace '/' with '.' in package name 1039 } 1040 const char* fmt = "Prohibited package name: %s"; 1041 size_t len = strlen(fmt) + strlen(name); 1042 char* message = NEW_RESOURCE_ARRAY(char, len); 1043 jio_snprintf(message, len, fmt, name); 1044 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1045 vmSymbols::java_lang_SecurityException(), message); 1046 } 1047 1048 if (!HAS_PENDING_EXCEPTION) { 1049 assert(!parsed_name.is_null(), "Sanity"); 1050 assert(class_name.is_null() || class_name() == parsed_name(), 1051 "name mismatch"); 1052 // Verification prevents us from creating names with dots in them, this 1053 // asserts that that's the case. 1054 assert(is_internal_format(parsed_name), 1055 "external class name format used internally"); 1056 1057 // Add class just loaded 1058 define_instance_class(k, THREAD); 1059 } 1060 1061 // If parsing the class file or define_instance_class failed, we 1062 // need to remove the placeholder added on our behalf. But we 1063 // must make sure parsed_name is valid first (it won't be if we had 1064 // a format error before the class was parsed far enough to 1065 // find the name). 1066 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) { 1067 unsigned int p_hash = placeholders()->compute_hash(parsed_name, 1068 class_loader); 1069 int p_index = placeholders()->hash_to_index(p_hash); 1070 { 1071 MutexLocker mu(SystemDictionary_lock, THREAD); 1072 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); 1073 SystemDictionary_lock->notify_all(); 1074 } 1075 return NULL; 1076 } 1077 1078 // Make sure that we didn't leave a place holder in the 1079 // SystemDictionary; this is only done on success 1080 debug_only( { 1081 if (!HAS_PENDING_EXCEPTION) { 1082 assert(!parsed_name.is_null(), "parsed_name is still null?"); 1083 symbolHandle h_name (THREAD, k->name()); 1084 Handle h_loader (THREAD, k->class_loader()); 1085 1086 MutexLocker mu(SystemDictionary_lock, THREAD); 1087 1088 oop check = find_class_or_placeholder(parsed_name, class_loader); 1089 assert(check == k(), "should be present in the dictionary"); 1090 1091 oop check2 = find_class_or_placeholder(h_name, h_loader); 1092 assert(check == check2, "name inconsistancy in SystemDictionary"); 1093 } 1094 } ); 1095 1096 return k(); 1097} 1098 1099 1100void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length, 1101 int number_of_entries) { 1102 assert(length == _nof_buckets * sizeof(HashtableBucket), 1103 "bad shared dictionary size."); 1104 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1105} 1106 1107 1108// If there is a shared dictionary, then find the entry for the 1109// given shared system class, if any. 1110 1111klassOop SystemDictionary::find_shared_class(symbolHandle class_name) { 1112 if (shared_dictionary() != NULL) { 1113 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle()); 1114 int d_index = dictionary()->hash_to_index(d_hash); 1115 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1116 } else { 1117 return NULL; 1118 } 1119} 1120 1121 1122// Load a class from the shared spaces (found through the shared system 1123// dictionary). Force the superclass and all interfaces to be loaded. 1124// Update the class definition to include sibling classes and no 1125// subclasses (yet). [Classes in the shared space are not part of the 1126// object hierarchy until loaded.] 1127 1128instanceKlassHandle SystemDictionary::load_shared_class( 1129 symbolHandle class_name, Handle class_loader, TRAPS) { 1130 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1131 return load_shared_class(ik, class_loader, THREAD); 1132} 1133 1134// Note well! Changes to this method may affect oop access order 1135// in the shared archive. Please take care to not make changes that 1136// adversely affect cold start time by changing the oop access order 1137// that is specified in dump.cpp MarkAndMoveOrderedReadOnly and 1138// MarkAndMoveOrderedReadWrite closures. 1139instanceKlassHandle SystemDictionary::load_shared_class( 1140 instanceKlassHandle ik, Handle class_loader, TRAPS) { 1141 assert(class_loader.is_null(), "non-null classloader for shared class?"); 1142 if (ik.not_null()) { 1143 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1144 symbolHandle class_name(THREAD, ik->name()); 1145 1146 // Found the class, now load the superclass and interfaces. If they 1147 // are shared, add them to the main system dictionary and reset 1148 // their hierarchy references (supers, subs, and interfaces). 1149 1150 if (ik->super() != NULL) { 1151 symbolHandle cn(THREAD, ik->super()->klass_part()->name()); 1152 resolve_super_or_fail(class_name, cn, 1153 class_loader, Handle(), true, CHECK_(nh)); 1154 } 1155 1156 objArrayHandle interfaces (THREAD, ik->local_interfaces()); 1157 int num_interfaces = interfaces->length(); 1158 for (int index = 0; index < num_interfaces; index++) { 1159 klassOop k = klassOop(interfaces->obj_at(index)); 1160 1161 // Note: can not use instanceKlass::cast here because 1162 // interfaces' instanceKlass's C++ vtbls haven't been 1163 // reinitialized yet (they will be once the interface classes 1164 // are loaded) 1165 symbolHandle name (THREAD, k->klass_part()->name()); 1166 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); 1167 } 1168 1169 // Adjust methods to recover missing data. They need addresses for 1170 // interpreter entry points and their default native method address 1171 // must be reset. 1172 1173 // Updating methods must be done under a lock so multiple 1174 // threads don't update these in parallel 1175 // Shared classes are all currently loaded by the bootstrap 1176 // classloader, so this will never cause a deadlock on 1177 // a custom class loader lock. 1178 1179 { 1180 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1181 check_loader_lock_contention(lockObject, THREAD); 1182 ObjectLocker ol(lockObject, THREAD, true); 1183 1184 objArrayHandle methods (THREAD, ik->methods()); 1185 int num_methods = methods->length(); 1186 for (int index2 = 0; index2 < num_methods; ++index2) { 1187 methodHandle m(THREAD, methodOop(methods->obj_at(index2))); 1188 m()->link_method(m, CHECK_(nh)); 1189 } 1190 } 1191 1192 if (TraceClassLoading) { 1193 ResourceMark rm; 1194 tty->print("[Loaded %s", ik->external_name()); 1195 tty->print(" from shared objects file"); 1196 tty->print_cr("]"); 1197 } 1198 // notify a class loaded from shared object 1199 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()), 1200 true /* shared class */); 1201 } 1202 return ik; 1203} 1204 1205#ifdef KERNEL 1206// Some classes on the bootstrap class path haven't been installed on the 1207// system yet. Call the DownloadManager method to make them appear in the 1208// bootstrap class path and try again to load the named class. 1209// Note that with delegation class loaders all classes in another loader will 1210// first try to call this so it'd better be fast!! 1211static instanceKlassHandle download_and_retry_class_load( 1212 symbolHandle class_name, 1213 TRAPS) { 1214 1215 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass(); 1216 instanceKlassHandle nk; 1217 1218 // If download manager class isn't loaded just return. 1219 if (dlm == NULL) return nk; 1220 1221 { HandleMark hm(THREAD); 1222 ResourceMark rm(THREAD); 1223 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk)); 1224 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk)); 1225 1226 // return value 1227 JavaValue result(T_OBJECT); 1228 1229 // Call the DownloadManager. We assume that it has a lock because 1230 // multiple classes could be not found and downloaded at the same time. 1231 // class sun.misc.DownloadManager; 1232 // public static String getBootClassPathEntryForClass(String className); 1233 JavaCalls::call_static(&result, 1234 KlassHandle(THREAD, dlm), 1235 vmSymbolHandles::getBootClassPathEntryForClass_name(), 1236 vmSymbolHandles::string_string_signature(), 1237 class_string, 1238 CHECK_(nk)); 1239 1240 // Get result.string and add to bootclasspath 1241 assert(result.get_type() == T_OBJECT, "just checking"); 1242 oop obj = (oop) result.get_jobject(); 1243 if (obj == NULL) { return nk; } 1244 1245 char* new_class_name = java_lang_String::as_utf8_string(obj); 1246 1247 // lock the loader 1248 // we use this lock because JVMTI does. 1249 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock()); 1250 1251 ObjectLocker ol(loader_lock, THREAD); 1252 // add the file to the bootclasspath 1253 ClassLoader::update_class_path_entry_list(new_class_name, true); 1254 } // end HandleMark 1255 1256 if (TraceClassLoading) { 1257 ClassLoader::print_bootclasspath(); 1258 } 1259 return ClassLoader::load_classfile(class_name, CHECK_(nk)); 1260} 1261#endif // KERNEL 1262 1263 1264instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) { 1265 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1266 if (class_loader.is_null()) { 1267 // Search the shared system dictionary for classes preloaded into the 1268 // shared spaces. 1269 instanceKlassHandle k; 1270 k = load_shared_class(class_name, class_loader, THREAD); 1271 1272 if (k.is_null()) { 1273 // Use VM class loader 1274 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); 1275 } 1276 1277#ifdef KERNEL 1278 // If the VM class loader has failed to load the class, call the 1279 // DownloadManager class to make it magically appear on the classpath 1280 // and try again. This is only configured with the Kernel VM. 1281 if (k.is_null()) { 1282 k = download_and_retry_class_load(class_name, CHECK_(nh)); 1283 } 1284#endif // KERNEL 1285 1286 // find_or_define_instance_class may return a different k 1287 if (!k.is_null()) { 1288 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1289 } 1290 return k; 1291 } else { 1292 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1293 ResourceMark rm(THREAD); 1294 1295 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1296 // Translate to external class name format, i.e., convert '/' chars to '.' 1297 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1298 1299 JavaValue result(T_OBJECT); 1300 1301 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass()); 1302 1303 // UnsyncloadClass option means don't synchronize loadClass() calls. 1304 // loadClassInternal() is synchronized and public loadClass(String) is not. 1305 // This flag is for diagnostic purposes only. It is risky to call 1306 // custom class loaders without synchronization. 1307 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1308 // findClass, this flag risks unexpected timing bugs in the field. 1309 // Do NOT assume this will be supported in future releases. 1310 if (!UnsyncloadClass && has_loadClassInternal()) { 1311 JavaCalls::call_special(&result, 1312 class_loader, 1313 spec_klass, 1314 vmSymbolHandles::loadClassInternal_name(), 1315 vmSymbolHandles::string_class_signature(), 1316 string, 1317 CHECK_(nh)); 1318 } else { 1319 JavaCalls::call_virtual(&result, 1320 class_loader, 1321 spec_klass, 1322 vmSymbolHandles::loadClass_name(), 1323 vmSymbolHandles::string_class_signature(), 1324 string, 1325 CHECK_(nh)); 1326 } 1327 1328 assert(result.get_type() == T_OBJECT, "just checking"); 1329 oop obj = (oop) result.get_jobject(); 1330 1331 // Primitive classes return null since forName() can not be 1332 // used to obtain any of the Class objects representing primitives or void 1333 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1334 instanceKlassHandle k = 1335 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj)); 1336 // For user defined Java class loaders, check that the name returned is 1337 // the same as that requested. This check is done for the bootstrap 1338 // loader when parsing the class file. 1339 if (class_name() == k->name()) { 1340 return k; 1341 } 1342 } 1343 // Class is not found or has the wrong name, return NULL 1344 return nh; 1345 } 1346} 1347 1348void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1349 1350 Handle class_loader_h(THREAD, k->class_loader()); 1351 1352 // for bootstrap classloader don't acquire lock 1353 if (!class_loader_h.is_null()) { 1354 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1355 compute_loader_lock_object(class_loader_h, THREAD)), 1356 "define called without lock"); 1357 } 1358 1359 1360 // Check class-loading constraints. Throw exception if violation is detected. 1361 // Grabs and releases SystemDictionary_lock 1362 // The check_constraints/find_class call and update_dictionary sequence 1363 // must be "atomic" for a specific class/classloader pair so we never 1364 // define two different instanceKlasses for that class/classloader pair. 1365 // Existing classloaders will call define_instance_class with the 1366 // classloader lock held 1367 // Parallel classloaders will call find_or_define_instance_class 1368 // which will require a token to perform the define class 1369 symbolHandle name_h(THREAD, k->name()); 1370 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h); 1371 int d_index = dictionary()->hash_to_index(d_hash); 1372 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1373 1374 // Register class just loaded with class loader (placed in Vector) 1375 // Note we do this before updating the dictionary, as this can 1376 // fail with an OutOfMemoryError (if it does, we will *not* put this 1377 // class in the dictionary and will not update the class hierarchy). 1378 if (k->class_loader() != NULL) { 1379 methodHandle m(THREAD, Universe::loader_addClass_method()); 1380 JavaValue result(T_VOID); 1381 JavaCallArguments args(class_loader_h); 1382 args.push_oop(Handle(THREAD, k->java_mirror())); 1383 JavaCalls::call(&result, m, &args, CHECK); 1384 } 1385 1386 // Add the new class. We need recompile lock during update of CHA. 1387 { 1388 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h); 1389 int p_index = placeholders()->hash_to_index(p_hash); 1390 1391 MutexLocker mu_r(Compile_lock, THREAD); 1392 1393 // Add to class hierarchy, initialize vtables, and do possible 1394 // deoptimizations. 1395 add_to_hierarchy(k, CHECK); // No exception, but can block 1396 1397 // Add to systemDictionary - so other classes can see it. 1398 // Grabs and releases SystemDictionary_lock 1399 update_dictionary(d_index, d_hash, p_index, p_hash, 1400 k, class_loader_h, THREAD); 1401 } 1402 k->eager_initialize(THREAD); 1403 1404 // notify jvmti 1405 if (JvmtiExport::should_post_class_load()) { 1406 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1407 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1408 1409 } 1410} 1411 1412// Support parallel classloading 1413// Initial implementation for bootstrap classloader 1414// For future: 1415// For custom class loaders that support parallel classloading, 1416// in case they do not synchronize around 1417// FindLoadedClass/DefineClass calls, we check for parallel 1418// loading for them, wait if a defineClass is in progress 1419// and return the initial requestor's results 1420// For better performance, the class loaders should synchronize 1421// findClass(), i.e. FindLoadedClass/DefineClass or they 1422// potentially waste time reading and parsing the bytestream. 1423// Note: VM callers should ensure consistency of k/class_name,class_loader 1424instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1425 1426 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1427 1428 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); 1429 int d_index = dictionary()->hash_to_index(d_hash); 1430 1431// Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1432 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader); 1433 int p_index = placeholders()->hash_to_index(p_hash); 1434 PlaceholderEntry* probe; 1435 1436 { 1437 MutexLocker mu(SystemDictionary_lock, THREAD); 1438 // First check if class already defined 1439 klassOop check = find_class(d_index, d_hash, class_name, class_loader); 1440 if (check != NULL) { 1441 return(instanceKlassHandle(THREAD, check)); 1442 } 1443 1444 // Acquire define token for this class/classloader 1445 symbolHandle nullsymbolHandle; 1446 probe = placeholders()->find_and_add(p_index, p_hash, class_name, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD); 1447 // Check if another thread defining in parallel 1448 if (probe->definer() == NULL) { 1449 // Thread will define the class 1450 probe->set_definer(THREAD); 1451 } else { 1452 // Wait for defining thread to finish and return results 1453 while (probe->definer() != NULL) { 1454 SystemDictionary_lock->wait(); 1455 } 1456 if (probe->instanceKlass() != NULL) { 1457 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); 1458 return(instanceKlassHandle(THREAD, probe->instanceKlass())); 1459 } else { 1460 // If definer had an error, try again as any new thread would 1461 probe->set_definer(THREAD); 1462#ifdef ASSERT 1463 klassOop check = find_class(d_index, d_hash, class_name, class_loader); 1464 assert(check == NULL, "definer missed recording success"); 1465#endif 1466 } 1467 } 1468 } 1469 1470 define_instance_class(k, THREAD); 1471 1472 Handle linkage_exception = Handle(); // null handle 1473 1474 // definer must notify any waiting threads 1475 { 1476 MutexLocker mu(SystemDictionary_lock, THREAD); 1477 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, class_name, class_loader); 1478 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1479 if (probe != NULL) { 1480 if (HAS_PENDING_EXCEPTION) { 1481 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1482 CLEAR_PENDING_EXCEPTION; 1483 } else { 1484 probe->set_instanceKlass(k()); 1485 } 1486 probe->set_definer(NULL); 1487 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); 1488 SystemDictionary_lock->notify_all(); 1489 } 1490 } 1491 1492 // Can't throw exception while holding lock due to rank ordering 1493 if (linkage_exception() != NULL) { 1494 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1495 } 1496 1497 return k; 1498} 1499 1500Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1501 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1502 if (class_loader.is_null()) { 1503 return Handle(THREAD, _system_loader_lock_obj); 1504 } else { 1505 return class_loader; 1506 } 1507} 1508 1509// This method is added to check how often we have to wait to grab loader 1510// lock. The results are being recorded in the performance counters defined in 1511// ClassLoader::_sync_systemLoaderLockContentionRate and 1512// ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1513void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1514 if (!UsePerfData) { 1515 return; 1516 } 1517 1518 assert(!loader_lock.is_null(), "NULL lock object"); 1519 1520 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1521 == ObjectSynchronizer::owner_other) { 1522 // contention will likely happen, so increment the corresponding 1523 // contention counter. 1524 if (loader_lock() == _system_loader_lock_obj) { 1525 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1526 } else { 1527 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1528 } 1529 } 1530} 1531 1532// ---------------------------------------------------------------------------- 1533// Lookup 1534 1535klassOop SystemDictionary::find_class(int index, unsigned int hash, 1536 symbolHandle class_name, 1537 Handle class_loader) { 1538 assert_locked_or_safepoint(SystemDictionary_lock); 1539 assert (index == dictionary()->index_for(class_name, class_loader), 1540 "incorrect index?"); 1541 1542 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader); 1543 return k; 1544} 1545 1546 1547// Basic find on classes in the midst of being loaded 1548symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash, 1549 symbolHandle class_name, 1550 Handle class_loader) { 1551 assert_locked_or_safepoint(SystemDictionary_lock); 1552 1553 return placeholders()->find_entry(index, hash, class_name, class_loader); 1554} 1555 1556 1557// Used for assertions and verification only 1558oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name, 1559 Handle class_loader) { 1560 #ifndef ASSERT 1561 guarantee(VerifyBeforeGC || 1562 VerifyDuringGC || 1563 VerifyBeforeExit || 1564 VerifyAfterGC, "too expensive"); 1565 #endif 1566 assert_locked_or_safepoint(SystemDictionary_lock); 1567 symbolOop class_name_ = class_name(); 1568 oop class_loader_ = class_loader(); 1569 1570 // First look in the loaded class array 1571 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); 1572 int d_index = dictionary()->hash_to_index(d_hash); 1573 oop lookup = find_class(d_index, d_hash, class_name, class_loader); 1574 1575 if (lookup == NULL) { 1576 // Next try the placeholders 1577 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader); 1578 int p_index = placeholders()->hash_to_index(p_hash); 1579 lookup = find_placeholder(p_index, p_hash, class_name, class_loader); 1580 } 1581 1582 return lookup; 1583} 1584 1585 1586// Get the next class in the diictionary. 1587klassOop SystemDictionary::try_get_next_class() { 1588 return dictionary()->try_get_next_class(); 1589} 1590 1591 1592// ---------------------------------------------------------------------------- 1593// Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1594// is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1595// before a new class is used. 1596 1597void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1598 assert(k.not_null(), "just checking"); 1599 // Link into hierachy. Make sure the vtables are initialized before linking into 1600 k->append_to_sibling_list(); // add to superklass/sibling list 1601 k->process_interfaces(THREAD); // handle all "implements" declarations 1602 k->set_init_state(instanceKlass::loaded); 1603 // Now flush all code that depended on old class hierarchy. 1604 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1605 // Also, first reinitialize vtable because it may have gotten out of synch 1606 // while the new class wasn't connected to the class hierarchy. 1607 Universe::flush_dependents_on(k); 1608} 1609 1610 1611// ---------------------------------------------------------------------------- 1612// GC support 1613 1614// Following roots during mark-sweep is separated in two phases. 1615// 1616// The first phase follows preloaded classes and all other system 1617// classes, since these will never get unloaded anyway. 1618// 1619// The second phase removes (unloads) unreachable classes from the 1620// system dictionary and follows the remaining classes' contents. 1621 1622void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1623 // Follow preloaded classes/mirrors and system loader object 1624 blk->do_oop(&_java_system_loader); 1625 preloaded_oops_do(blk); 1626 always_strong_classes_do(blk); 1627} 1628 1629 1630void SystemDictionary::always_strong_classes_do(OopClosure* blk) { 1631 // Follow all system classes and temporary placeholders in dictionary 1632 dictionary()->always_strong_classes_do(blk); 1633 1634 // Placeholders. These are *always* strong roots, as they 1635 // represent classes we're actively loading. 1636 placeholders_do(blk); 1637 1638 // Loader constraints. We must keep the symbolOop used in the name alive. 1639 constraints()->always_strong_classes_do(blk); 1640 1641 // Resolution errors keep the symbolOop for the error alive 1642 resolution_errors()->always_strong_classes_do(blk); 1643} 1644 1645 1646void SystemDictionary::placeholders_do(OopClosure* blk) { 1647 placeholders()->oops_do(blk); 1648} 1649 1650 1651bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { 1652 bool result = dictionary()->do_unloading(is_alive); 1653 constraints()->purge_loader_constraints(is_alive); 1654 resolution_errors()->purge_resolution_errors(is_alive); 1655 return result; 1656} 1657 1658 1659// The mirrors are scanned by shared_oops_do() which is 1660// not called by oops_do(). In order to process oops in 1661// a necessary order, shared_oops_do() is call by 1662// Universe::oops_do(). 1663void SystemDictionary::oops_do(OopClosure* f) { 1664 // Adjust preloaded classes and system loader object 1665 f->do_oop(&_java_system_loader); 1666 preloaded_oops_do(f); 1667 1668 lazily_loaded_oops_do(f); 1669 1670 // Adjust dictionary 1671 dictionary()->oops_do(f); 1672 1673 // Partially loaded classes 1674 placeholders()->oops_do(f); 1675 1676 // Adjust constraint table 1677 constraints()->oops_do(f); 1678 1679 // Adjust resolution error table 1680 resolution_errors()->oops_do(f); 1681} 1682 1683 1684void SystemDictionary::preloaded_oops_do(OopClosure* f) { 1685 f->do_oop((oop*) &_string_klass); 1686 f->do_oop((oop*) &_object_klass); 1687 f->do_oop((oop*) &_class_klass); 1688 f->do_oop((oop*) &_cloneable_klass); 1689 f->do_oop((oop*) &_classloader_klass); 1690 f->do_oop((oop*) &_serializable_klass); 1691 f->do_oop((oop*) &_system_klass); 1692 1693 f->do_oop((oop*) &_throwable_klass); 1694 f->do_oop((oop*) &_error_klass); 1695 f->do_oop((oop*) &_threaddeath_klass); 1696 f->do_oop((oop*) &_exception_klass); 1697 f->do_oop((oop*) &_runtime_exception_klass); 1698 f->do_oop((oop*) &_classNotFoundException_klass); 1699 f->do_oop((oop*) &_noClassDefFoundError_klass); 1700 f->do_oop((oop*) &_linkageError_klass); 1701 f->do_oop((oop*) &_classCastException_klass); 1702 f->do_oop((oop*) &_arrayStoreException_klass); 1703 f->do_oop((oop*) &_virtualMachineError_klass); 1704 f->do_oop((oop*) &_outOfMemoryError_klass); 1705 f->do_oop((oop*) &_StackOverflowError_klass); 1706 f->do_oop((oop*) &_illegalMonitorStateException_klass); 1707 f->do_oop((oop*) &_protectionDomain_klass); 1708 f->do_oop((oop*) &_AccessControlContext_klass); 1709 1710 f->do_oop((oop*) &_reference_klass); 1711 f->do_oop((oop*) &_soft_reference_klass); 1712 f->do_oop((oop*) &_weak_reference_klass); 1713 f->do_oop((oop*) &_final_reference_klass); 1714 f->do_oop((oop*) &_phantom_reference_klass); 1715 f->do_oop((oop*) &_finalizer_klass); 1716 1717 f->do_oop((oop*) &_thread_klass); 1718 f->do_oop((oop*) &_threadGroup_klass); 1719 f->do_oop((oop*) &_properties_klass); 1720 f->do_oop((oop*) &_reflect_accessible_object_klass); 1721 f->do_oop((oop*) &_reflect_field_klass); 1722 f->do_oop((oop*) &_reflect_method_klass); 1723 f->do_oop((oop*) &_reflect_constructor_klass); 1724 f->do_oop((oop*) &_reflect_magic_klass); 1725 f->do_oop((oop*) &_reflect_method_accessor_klass); 1726 f->do_oop((oop*) &_reflect_constructor_accessor_klass); 1727 f->do_oop((oop*) &_reflect_delegating_classloader_klass); 1728 f->do_oop((oop*) &_reflect_constant_pool_klass); 1729 f->do_oop((oop*) &_reflect_unsafe_static_field_accessor_impl_klass); 1730 1731 f->do_oop((oop*) &_stringBuffer_klass); 1732 f->do_oop((oop*) &_vector_klass); 1733 f->do_oop((oop*) &_hashtable_klass); 1734 1735 f->do_oop((oop*) &_stackTraceElement_klass); 1736 1737 f->do_oop((oop*) &_java_nio_Buffer_klass); 1738 1739 f->do_oop((oop*) &_sun_misc_AtomicLongCSImpl_klass); 1740 f->do_oop((oop*) &_sun_jkernel_DownloadManager_klass); 1741 1742 f->do_oop((oop*) &_boolean_klass); 1743 f->do_oop((oop*) &_char_klass); 1744 f->do_oop((oop*) &_float_klass); 1745 f->do_oop((oop*) &_double_klass); 1746 f->do_oop((oop*) &_byte_klass); 1747 f->do_oop((oop*) &_short_klass); 1748 f->do_oop((oop*) &_int_klass); 1749 f->do_oop((oop*) &_long_klass); 1750 { 1751 for (int i = 0; i < T_VOID+1; i++) { 1752 if (_box_klasses[i] != NULL) { 1753 assert(i >= T_BOOLEAN, "checking"); 1754 f->do_oop((oop*) &_box_klasses[i]); 1755 } 1756 } 1757 } 1758 1759 // The basic type mirrors would have already been processed in 1760 // Universe::oops_do(), via a call to shared_oops_do(), so should 1761 // not be processed again. 1762 1763 f->do_oop((oop*) &_system_loader_lock_obj); 1764 FilteredFieldsMap::klasses_oops_do(f); 1765} 1766 1767void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) { 1768 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass); 1769} 1770 1771// Just the classes from defining class loaders 1772// Don't iterate over placeholders 1773void SystemDictionary::classes_do(void f(klassOop)) { 1774 dictionary()->classes_do(f); 1775} 1776 1777// Added for initialize_itable_for_klass 1778// Just the classes from defining class loaders 1779// Don't iterate over placeholders 1780void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) { 1781 dictionary()->classes_do(f, CHECK); 1782} 1783 1784// All classes, and their class loaders 1785// Don't iterate over placeholders 1786void SystemDictionary::classes_do(void f(klassOop, oop)) { 1787 dictionary()->classes_do(f); 1788} 1789 1790// All classes, and their class loaders 1791// (added for helpers that use HandleMarks and ResourceMarks) 1792// Don't iterate over placeholders 1793void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) { 1794 dictionary()->classes_do(f, CHECK); 1795} 1796 1797void SystemDictionary::placeholders_do(void f(symbolOop, oop)) { 1798 placeholders()->entries_do(f); 1799} 1800 1801void SystemDictionary::methods_do(void f(methodOop)) { 1802 dictionary()->methods_do(f); 1803} 1804 1805// ---------------------------------------------------------------------------- 1806// Lazily load klasses 1807 1808void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1809 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); 1810 1811 // if multiple threads calling this function, only one thread will load 1812 // the class. The other threads will find the loaded version once the 1813 // class is loaded. 1814 klassOop aos = _abstract_ownable_synchronizer_klass; 1815 if (aos == NULL) { 1816 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1817 // Force a fence to prevent any read before the write completes 1818 OrderAccess::fence(); 1819 _abstract_ownable_synchronizer_klass = k; 1820 } 1821} 1822 1823// ---------------------------------------------------------------------------- 1824// Initialization 1825 1826void SystemDictionary::initialize(TRAPS) { 1827 // Allocate arrays 1828 assert(dictionary() == NULL, 1829 "SystemDictionary should only be initialized once"); 1830 _dictionary = new Dictionary(_nof_buckets); 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 1836 // Allocate private object used as system class loader lock 1837 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK); 1838 // Initialize basic classes 1839 initialize_preloaded_classes(CHECK); 1840} 1841 1842 1843void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1844 assert(_object_klass == NULL, "preloaded classes should only be initialized once"); 1845 // Preload commonly used klasses 1846 _object_klass = resolve_or_fail(vmSymbolHandles::java_lang_Object(), true, CHECK); 1847 _string_klass = resolve_or_fail(vmSymbolHandles::java_lang_String(), true, CHECK); 1848 _class_klass = resolve_or_fail(vmSymbolHandles::java_lang_Class(), true, CHECK); 1849 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(_class_klass)); 1850 // Fixup mirrors for classes loaded before java.lang.Class. 1851 // These calls iterate over the objects currently in the perm gen 1852 // so calling them at this point is matters (not before when there 1853 // are fewer objects and not later after there are more objects 1854 // in the perm gen. 1855 Universe::initialize_basic_type_mirrors(CHECK); 1856 Universe::fixup_mirrors(CHECK); 1857 1858 _cloneable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Cloneable(), true, CHECK); 1859 _classloader_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassLoader(), true, CHECK); 1860 _serializable_klass = resolve_or_fail(vmSymbolHandles::java_io_Serializable(), true, CHECK); 1861 _system_klass = resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK); 1862 1863 _throwable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Throwable(), true, CHECK); 1864 _error_klass = resolve_or_fail(vmSymbolHandles::java_lang_Error(), true, CHECK); 1865 _threaddeath_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadDeath(), true, CHECK); 1866 _exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_Exception(), true, CHECK); 1867 _runtime_exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_RuntimeException(), true, CHECK); 1868 _protectionDomain_klass = resolve_or_fail(vmSymbolHandles::java_security_ProtectionDomain(), true, CHECK); 1869 _AccessControlContext_klass = resolve_or_fail(vmSymbolHandles::java_security_AccessControlContext(), true, CHECK); 1870 _classNotFoundException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassNotFoundException(), true, CHECK); 1871 _noClassDefFoundError_klass = resolve_or_fail(vmSymbolHandles::java_lang_NoClassDefFoundError(), true, CHECK); 1872 _linkageError_klass = resolve_or_fail(vmSymbolHandles::java_lang_LinkageError(), true, CHECK); 1873 _classCastException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassCastException(), true, CHECK); 1874 _arrayStoreException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ArrayStoreException(), true, CHECK); 1875 _virtualMachineError_klass = resolve_or_fail(vmSymbolHandles::java_lang_VirtualMachineError(), true, CHECK); 1876 _outOfMemoryError_klass = resolve_or_fail(vmSymbolHandles::java_lang_OutOfMemoryError(), true, CHECK); 1877 _StackOverflowError_klass = resolve_or_fail(vmSymbolHandles::java_lang_StackOverflowError(), true, CHECK); 1878 _illegalMonitorStateException_klass = resolve_or_fail(vmSymbolHandles::java_lang_IllegalMonitorStateException(), true, CHECK); 1879 1880 // Preload ref klasses and set reference types 1881 _reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Reference(), true, CHECK); 1882 instanceKlass::cast(_reference_klass)->set_reference_type(REF_OTHER); 1883 instanceRefKlass::update_nonstatic_oop_maps(_reference_klass); 1884 1885 _soft_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_SoftReference(), true, CHECK); 1886 instanceKlass::cast(_soft_reference_klass)->set_reference_type(REF_SOFT); 1887 _weak_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_WeakReference(), true, CHECK); 1888 instanceKlass::cast(_weak_reference_klass)->set_reference_type(REF_WEAK); 1889 _final_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_FinalReference(), true, CHECK); 1890 instanceKlass::cast(_final_reference_klass)->set_reference_type(REF_FINAL); 1891 _phantom_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_PhantomReference(), true, CHECK); 1892 instanceKlass::cast(_phantom_reference_klass)->set_reference_type(REF_PHANTOM); 1893 _finalizer_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Finalizer(), true, CHECK); 1894 1895 _thread_klass = resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK); 1896 _threadGroup_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK); 1897 _properties_klass = resolve_or_fail(vmSymbolHandles::java_util_Properties(), true, CHECK); 1898 _reflect_accessible_object_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_AccessibleObject(), true, CHECK); 1899 _reflect_field_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Field(), true, CHECK); 1900 _reflect_method_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Method(), true, CHECK); 1901 _reflect_constructor_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Constructor(), true, CHECK); 1902 // Universe::is_gte_jdk14x_version() is not set up by this point. 1903 // It's okay if these turn out to be NULL in non-1.4 JDKs. 1904 _reflect_magic_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MagicAccessorImpl(), CHECK); 1905 _reflect_method_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MethodAccessorImpl(), CHECK); 1906 _reflect_constructor_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstructorAccessorImpl(), CHECK); 1907 _reflect_delegating_classloader_klass = resolve_or_null(vmSymbolHandles::sun_reflect_DelegatingClassLoader(), CHECK); 1908 _reflect_constant_pool_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstantPool(), CHECK); 1909 _reflect_unsafe_static_field_accessor_impl_klass = resolve_or_null(vmSymbolHandles::sun_reflect_UnsafeStaticFieldAccessorImpl(), CHECK); 1910 1911 _vector_klass = resolve_or_fail(vmSymbolHandles::java_util_Vector(), true, CHECK); 1912 _hashtable_klass = resolve_or_fail(vmSymbolHandles::java_util_Hashtable(), true, CHECK); 1913 _stringBuffer_klass = resolve_or_fail(vmSymbolHandles::java_lang_StringBuffer(), true, CHECK); 1914 1915 // It's NULL in non-1.4 JDKs. 1916 _stackTraceElement_klass = resolve_or_null(vmSymbolHandles::java_lang_StackTraceElement(), CHECK); 1917 1918 // Universe::is_gte_jdk14x_version() is not set up by this point. 1919 // It's okay if this turns out to be NULL in non-1.4 JDKs. 1920 _java_nio_Buffer_klass = resolve_or_null(vmSymbolHandles::java_nio_Buffer(), CHECK); 1921 1922 // If this class isn't present, it won't be referenced. 1923 _sun_misc_AtomicLongCSImpl_klass = resolve_or_null(vmSymbolHandles::sun_misc_AtomicLongCSImpl(), CHECK); 1924#ifdef KERNEL 1925 _sun_jkernel_DownloadManager_klass = resolve_or_null(vmSymbolHandles::sun_jkernel_DownloadManager(), CHECK); 1926 if (_sun_jkernel_DownloadManager_klass == NULL) { 1927 warning("Cannot find sun/jkernel/DownloadManager"); 1928 } 1929#endif // KERNEL 1930 1931 // Preload boxing klasses 1932 _boolean_klass = resolve_or_fail(vmSymbolHandles::java_lang_Boolean(), true, CHECK); 1933 _char_klass = resolve_or_fail(vmSymbolHandles::java_lang_Character(), true, CHECK); 1934 _float_klass = resolve_or_fail(vmSymbolHandles::java_lang_Float(), true, CHECK); 1935 _double_klass = resolve_or_fail(vmSymbolHandles::java_lang_Double(), true, CHECK); 1936 _byte_klass = resolve_or_fail(vmSymbolHandles::java_lang_Byte(), true, CHECK); 1937 _short_klass = resolve_or_fail(vmSymbolHandles::java_lang_Short(), true, CHECK); 1938 _int_klass = resolve_or_fail(vmSymbolHandles::java_lang_Integer(), true, CHECK); 1939 _long_klass = resolve_or_fail(vmSymbolHandles::java_lang_Long(), true, CHECK); 1940 1941 _box_klasses[T_BOOLEAN] = _boolean_klass; 1942 _box_klasses[T_CHAR] = _char_klass; 1943 _box_klasses[T_FLOAT] = _float_klass; 1944 _box_klasses[T_DOUBLE] = _double_klass; 1945 _box_klasses[T_BYTE] = _byte_klass; 1946 _box_klasses[T_SHORT] = _short_klass; 1947 _box_klasses[T_INT] = _int_klass; 1948 _box_klasses[T_LONG] = _long_klass; 1949 //_box_klasses[T_OBJECT] = _object_klass; 1950 //_box_klasses[T_ARRAY] = _object_klass; 1951 1952 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 1953 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 1954 _has_loadClassInternal = (method != NULL); 1955 } 1956 1957 { // Compute whether we should use checkPackageAccess or NOT 1958 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 1959 _has_checkPackageAccess = (method != NULL); 1960 } 1961} 1962 1963// Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 1964// If so, returns the basic type it holds. If not, returns T_OBJECT. 1965BasicType SystemDictionary::box_klass_type(klassOop k) { 1966 assert(k != NULL, ""); 1967 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 1968 if (_box_klasses[i] == k) 1969 return (BasicType)i; 1970 } 1971 return T_OBJECT; 1972} 1973 1974// Constraints on class loaders. The details of the algorithm can be 1975// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 1976// Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 1977// that the system dictionary needs to maintain a set of contraints that 1978// must be satisfied by all classes in the dictionary. 1979// if defining is true, then LinkageError if already in systemDictionary 1980// if initiating loader, then ok if instanceKlass matches existing entry 1981 1982void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 1983 instanceKlassHandle k, 1984 Handle class_loader, bool defining, 1985 TRAPS) { 1986 const char *linkage_error = NULL; 1987 { 1988 symbolHandle name (THREAD, k->name()); 1989 MutexLocker mu(SystemDictionary_lock, THREAD); 1990 1991 klassOop check = find_class(d_index, d_hash, name, class_loader); 1992 if (check != (klassOop)NULL) { 1993 // if different instanceKlass - duplicate class definition, 1994 // else - ok, class loaded by a different thread in parallel, 1995 // we should only have found it if it was done loading and ok to use 1996 // system dictionary only holds instance classes, placeholders 1997 // also holds array classes 1998 1999 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary"); 2000 if ((defining == true) || (k() != check)) { 2001 linkage_error = "loader (instance of %s): attempted duplicate class " 2002 "definition for name: \"%s\""; 2003 } else { 2004 return; 2005 } 2006 } 2007 2008#ifdef ASSERT 2009 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); 2010 int p_index = placeholders()->hash_to_index(p_hash); 2011 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); 2012 assert(ph_check == NULL || ph_check == name(), "invalid symbol"); 2013#endif 2014 2015 if (linkage_error == NULL) { 2016 if (constraints()->check_or_update(k, class_loader, name) == false) { 2017 linkage_error = "loader constraint violation: loader (instance of %s)" 2018 " previously initiated loading for a different type with name \"%s\""; 2019 } 2020 } 2021 } 2022 2023 // Throw error now if needed (cannot throw while holding 2024 // SystemDictionary_lock because of rank ordering) 2025 2026 if (linkage_error) { 2027 ResourceMark rm(THREAD); 2028 const char* class_loader_name = loader_name(class_loader()); 2029 char* type_name = k->name()->as_C_string(); 2030 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + 2031 strlen(type_name); 2032 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 2033 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); 2034 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 2035 } 2036} 2037 2038 2039// Update system dictionary - done after check_constraint and add_to_hierachy 2040// have been called. 2041void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 2042 int p_index, unsigned int p_hash, 2043 instanceKlassHandle k, 2044 Handle class_loader, 2045 TRAPS) { 2046 // Compile_lock prevents systemDictionary updates during compilations 2047 assert_locked_or_safepoint(Compile_lock); 2048 symbolHandle name (THREAD, k->name()); 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 // Check for a placeholder. If there, remove it and make a 2074 // new system dictionary entry. 2075 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); 2076 klassOop sd_check = find_class(d_index, d_hash, name, class_loader); 2077 if (sd_check == NULL) { 2078 dictionary()->add_klass(name, class_loader, k); 2079 notice_modification(); 2080 } 2081#ifdef ASSERT 2082 sd_check = find_class(d_index, d_hash, name, class_loader); 2083 assert (sd_check != NULL, "should have entry in system dictionary"); 2084// Changed to allow PH to remain to complete class circularity checking 2085// while only one thread can define a class at one time, multiple 2086// classes can resolve the superclass for a class at one time, 2087// and the placeholder is used to track that 2088// symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); 2089// assert (ph_check == NULL, "should not have a placeholder entry"); 2090#endif 2091 SystemDictionary_lock->notify_all(); 2092 } 2093} 2094 2095 2096klassOop SystemDictionary::find_constrained_instance_or_array_klass( 2097 symbolHandle class_name, Handle class_loader, TRAPS) { 2098 2099 // First see if it has been loaded directly. 2100 // Force the protection domain to be null. (This removes protection checks.) 2101 Handle no_protection_domain; 2102 klassOop klass = find_instance_or_array_klass(class_name, class_loader, 2103 no_protection_domain, CHECK_NULL); 2104 if (klass != NULL) 2105 return klass; 2106 2107 // Now look to see if it has been loaded elsewhere, and is subject to 2108 // a loader constraint that would require this loader to return the 2109 // klass that is already loaded. 2110 if (FieldType::is_array(class_name())) { 2111 // Array classes are hard because their klassOops are not kept in the 2112 // constraint table. The array klass may be constrained, but the elem class 2113 // may not be. 2114 jint dimension; 2115 symbolOop object_key; 2116 BasicType t = FieldType::get_array_info(class_name(), &dimension, 2117 &object_key, CHECK_(NULL)); 2118 if (t != T_OBJECT) { 2119 klass = Universe::typeArrayKlassObj(t); 2120 } else { 2121 symbolHandle elem_name(THREAD, object_key); 2122 MutexLocker mu(SystemDictionary_lock, THREAD); 2123 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD); 2124 } 2125 if (klass != NULL) { 2126 klass = Klass::cast(klass)->array_klass_or_null(dimension); 2127 } 2128 } else { 2129 MutexLocker mu(SystemDictionary_lock, THREAD); 2130 // Non-array classes are easy: simply check the constraint table. 2131 klass = constraints()->find_constrained_klass(class_name, class_loader); 2132 } 2133 2134 return klass; 2135} 2136 2137 2138bool SystemDictionary::add_loader_constraint(symbolHandle class_name, 2139 Handle class_loader1, 2140 Handle class_loader2, 2141 Thread* THREAD) { 2142 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1); 2143 int d_index1 = dictionary()->hash_to_index(d_hash1); 2144 2145 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2); 2146 int d_index2 = dictionary()->hash_to_index(d_hash2); 2147 2148 { 2149 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2150 2151 // Better never do a GC while we're holding these oops 2152 No_Safepoint_Verifier nosafepoint; 2153 2154 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1); 2155 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2); 2156 return constraints()->add_entry(class_name, klass1, class_loader1, 2157 klass2, class_loader2); 2158 } 2159} 2160 2161// Add entry to resolution error table to record the error when the first 2162// attempt to resolve a reference to a class has failed. 2163void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) { 2164 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2165 int index = resolution_errors()->hash_to_index(hash); 2166 { 2167 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2168 resolution_errors()->add_entry(index, hash, pool, which, error); 2169 } 2170} 2171 2172// Lookup resolution error table. Returns error if found, otherwise NULL. 2173symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { 2174 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2175 int index = resolution_errors()->hash_to_index(hash); 2176 { 2177 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2178 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2179 return (entry != NULL) ? entry->error() : (symbolOop)NULL; 2180 } 2181} 2182 2183 2184// Make sure all class components (including arrays) in the given 2185// signature will be resolved to the same class in both loaders. 2186// Returns the name of the type that failed a loader constraint check, or 2187// NULL if no constraint failed. The returned C string needs cleaning up 2188// with a ResourceMark in the caller 2189char* SystemDictionary::check_signature_loaders(symbolHandle signature, 2190 Handle loader1, Handle loader2, 2191 bool is_method, TRAPS) { 2192 // Nothing to do if loaders are the same. 2193 if (loader1() == loader2()) { 2194 return NULL; 2195 } 2196 2197 SignatureStream sig_strm(signature, is_method); 2198 while (!sig_strm.is_done()) { 2199 if (sig_strm.is_object()) { 2200 symbolOop s = sig_strm.as_symbol(CHECK_NULL); 2201 symbolHandle sig (THREAD, s); 2202 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2203 return sig()->as_C_string(); 2204 } 2205 } 2206 sig_strm.next(); 2207 } 2208 return NULL; 2209} 2210 2211 2212// Since the identity hash code for symbols changes when the symbols are 2213// moved from the regular perm gen (hash in the mark word) to the shared 2214// spaces (hash is the address), the classes loaded into the dictionary 2215// may be in the wrong buckets. 2216 2217void SystemDictionary::reorder_dictionary() { 2218 dictionary()->reorder_dictionary(); 2219} 2220 2221 2222void SystemDictionary::copy_buckets(char** top, char* end) { 2223 dictionary()->copy_buckets(top, end); 2224} 2225 2226 2227void SystemDictionary::copy_table(char** top, char* end) { 2228 dictionary()->copy_table(top, end); 2229} 2230 2231 2232void SystemDictionary::reverse() { 2233 dictionary()->reverse(); 2234} 2235 2236int SystemDictionary::number_of_classes() { 2237 return dictionary()->number_of_entries(); 2238} 2239 2240 2241// ---------------------------------------------------------------------------- 2242#ifndef PRODUCT 2243 2244void SystemDictionary::print() { 2245 dictionary()->print(); 2246 2247 // Placeholders 2248 GCMutexLocker mu(SystemDictionary_lock); 2249 placeholders()->print(); 2250 2251 // loader constraints - print under SD_lock 2252 constraints()->print(); 2253} 2254 2255#endif 2256 2257void SystemDictionary::verify() { 2258 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2259 guarantee(constraints() != NULL, 2260 "Verify of loader constraints failed"); 2261 guarantee(dictionary()->number_of_entries() >= 0 && 2262 placeholders()->number_of_entries() >= 0, 2263 "Verify of system dictionary failed"); 2264 2265 // Verify dictionary 2266 dictionary()->verify(); 2267 2268 GCMutexLocker mu(SystemDictionary_lock); 2269 placeholders()->verify(); 2270 2271 // Verify constraint table 2272 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2273 constraints()->verify(dictionary()); 2274} 2275 2276 2277void SystemDictionary::verify_obj_klass_present(Handle obj, 2278 symbolHandle class_name, 2279 Handle class_loader) { 2280 GCMutexLocker mu(SystemDictionary_lock); 2281 oop probe = find_class_or_placeholder(class_name, class_loader); 2282 if (probe == NULL) { 2283 probe = SystemDictionary::find_shared_class(class_name); 2284 } 2285 guarantee(probe != NULL && 2286 (!probe->is_klass() || probe == obj()), 2287 "Loaded klasses should be in SystemDictionary"); 2288} 2289 2290#ifndef PRODUCT 2291 2292// statistics code 2293class ClassStatistics: AllStatic { 2294 private: 2295 static int nclasses; // number of classes 2296 static int nmethods; // number of methods 2297 static int nmethoddata; // number of methodData 2298 static int class_size; // size of class objects in words 2299 static int method_size; // size of method objects in words 2300 static int debug_size; // size of debug info in methods 2301 static int methoddata_size; // size of methodData objects in words 2302 2303 static void do_class(klassOop k) { 2304 nclasses++; 2305 class_size += k->size(); 2306 if (k->klass_part()->oop_is_instance()) { 2307 instanceKlass* ik = (instanceKlass*)k->klass_part(); 2308 class_size += ik->methods()->size(); 2309 class_size += ik->constants()->size(); 2310 class_size += ik->local_interfaces()->size(); 2311 class_size += ik->transitive_interfaces()->size(); 2312 // We do not have to count implementors, since we only store one! 2313 class_size += ik->fields()->size(); 2314 } 2315 } 2316 2317 static void do_method(methodOop m) { 2318 nmethods++; 2319 method_size += m->size(); 2320 // class loader uses same objArray for empty vectors, so don't count these 2321 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size(); 2322 if (m->has_stackmap_table()) { 2323 method_size += m->stackmap_data()->size(); 2324 } 2325 2326 methodDataOop mdo = m->method_data(); 2327 if (mdo != NULL) { 2328 nmethoddata++; 2329 methoddata_size += mdo->size(); 2330 } 2331 } 2332 2333 public: 2334 static void print() { 2335 SystemDictionary::classes_do(do_class); 2336 SystemDictionary::methods_do(do_method); 2337 tty->print_cr("Class statistics:"); 2338 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); 2339 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, 2340 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); 2341 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); 2342 } 2343}; 2344 2345 2346int ClassStatistics::nclasses = 0; 2347int ClassStatistics::nmethods = 0; 2348int ClassStatistics::nmethoddata = 0; 2349int ClassStatistics::class_size = 0; 2350int ClassStatistics::method_size = 0; 2351int ClassStatistics::debug_size = 0; 2352int ClassStatistics::methoddata_size = 0; 2353 2354void SystemDictionary::print_class_statistics() { 2355 ResourceMark rm; 2356 ClassStatistics::print(); 2357} 2358 2359 2360class MethodStatistics: AllStatic { 2361 public: 2362 enum { 2363 max_parameter_size = 10 2364 }; 2365 private: 2366 2367 static int _number_of_methods; 2368 static int _number_of_final_methods; 2369 static int _number_of_static_methods; 2370 static int _number_of_native_methods; 2371 static int _number_of_synchronized_methods; 2372 static int _number_of_profiled_methods; 2373 static int _number_of_bytecodes; 2374 static int _parameter_size_profile[max_parameter_size]; 2375 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; 2376 2377 static void initialize() { 2378 _number_of_methods = 0; 2379 _number_of_final_methods = 0; 2380 _number_of_static_methods = 0; 2381 _number_of_native_methods = 0; 2382 _number_of_synchronized_methods = 0; 2383 _number_of_profiled_methods = 0; 2384 _number_of_bytecodes = 0; 2385 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; 2386 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; 2387 }; 2388 2389 static void do_method(methodOop m) { 2390 _number_of_methods++; 2391 // collect flag info 2392 if (m->is_final() ) _number_of_final_methods++; 2393 if (m->is_static() ) _number_of_static_methods++; 2394 if (m->is_native() ) _number_of_native_methods++; 2395 if (m->is_synchronized()) _number_of_synchronized_methods++; 2396 if (m->method_data() != NULL) _number_of_profiled_methods++; 2397 // collect parameter size info (add one for receiver, if any) 2398 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; 2399 // collect bytecodes info 2400 { 2401 Thread *thread = Thread::current(); 2402 HandleMark hm(thread); 2403 BytecodeStream s(methodHandle(thread, m)); 2404 Bytecodes::Code c; 2405 while ((c = s.next()) >= 0) { 2406 _number_of_bytecodes++; 2407 _bytecodes_profile[c]++; 2408 } 2409 } 2410 } 2411 2412 public: 2413 static void print() { 2414 initialize(); 2415 SystemDictionary::methods_do(do_method); 2416 // generate output 2417 tty->cr(); 2418 tty->print_cr("Method statistics (static):"); 2419 // flag distribution 2420 tty->cr(); 2421 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); 2422 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); 2423 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); 2424 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); 2425 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); 2426 // parameter size profile 2427 tty->cr(); 2428 { int tot = 0; 2429 int avg = 0; 2430 for (int i = 0; i < max_parameter_size; i++) { 2431 int n = _parameter_size_profile[i]; 2432 tot += n; 2433 avg += n*i; 2434 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); 2435 } 2436 assert(tot == _number_of_methods, "should be the same"); 2437 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); 2438 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); 2439 } 2440 // bytecodes profile 2441 tty->cr(); 2442 { int tot = 0; 2443 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { 2444 if (Bytecodes::is_defined(i)) { 2445 Bytecodes::Code c = Bytecodes::cast(i); 2446 int n = _bytecodes_profile[c]; 2447 tot += n; 2448 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); 2449 } 2450 } 2451 assert(tot == _number_of_bytecodes, "should be the same"); 2452 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); 2453 } 2454 tty->cr(); 2455 } 2456}; 2457 2458int MethodStatistics::_number_of_methods; 2459int MethodStatistics::_number_of_final_methods; 2460int MethodStatistics::_number_of_static_methods; 2461int MethodStatistics::_number_of_native_methods; 2462int MethodStatistics::_number_of_synchronized_methods; 2463int MethodStatistics::_number_of_profiled_methods; 2464int MethodStatistics::_number_of_bytecodes; 2465int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; 2466int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; 2467 2468 2469void SystemDictionary::print_method_statistics() { 2470 MethodStatistics::print(); 2471} 2472 2473#endif // PRODUCT 2474