systemDictionary.cpp revision 4445:0ca3dd0ffaba
1/* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoaderData.inline.hpp" 27#include "classfile/dictionary.hpp" 28#include "classfile/javaClasses.hpp" 29#include "classfile/loaderConstraints.hpp" 30#include "classfile/placeholders.hpp" 31#include "classfile/resolutionErrors.hpp" 32#include "classfile/systemDictionary.hpp" 33#include "classfile/vmSymbols.hpp" 34#include "compiler/compileBroker.hpp" 35#include "interpreter/bytecodeStream.hpp" 36#include "interpreter/interpreter.hpp" 37#include "memory/gcLocker.hpp" 38#include "memory/oopFactory.hpp" 39#include "oops/instanceKlass.hpp" 40#include "oops/instanceRefKlass.hpp" 41#include "oops/klass.inline.hpp" 42#include "oops/methodData.hpp" 43#include "oops/objArrayKlass.hpp" 44#include "oops/oop.inline.hpp" 45#include "oops/oop.inline2.hpp" 46#include "oops/typeArrayKlass.hpp" 47#include "prims/jvmtiEnvBase.hpp" 48#include "prims/methodHandles.hpp" 49#include "runtime/biasedLocking.hpp" 50#include "runtime/fieldType.hpp" 51#include "runtime/handles.inline.hpp" 52#include "runtime/java.hpp" 53#include "runtime/javaCalls.hpp" 54#include "runtime/mutexLocker.hpp" 55#include "runtime/signature.hpp" 56#include "services/classLoadingService.hpp" 57#include "services/threadService.hpp" 58 59 60Dictionary* SystemDictionary::_dictionary = NULL; 61PlaceholderTable* SystemDictionary::_placeholders = NULL; 62Dictionary* SystemDictionary::_shared_dictionary = NULL; 63LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 64ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 65SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 66 67 68int SystemDictionary::_number_of_modifications = 0; 69int SystemDictionary::_sdgeneration = 0; 70const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 71 20201,40423,99991}; 72 73oop SystemDictionary::_system_loader_lock_obj = NULL; 74 75Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 76 = { NULL /*, NULL...*/ }; 77 78Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 79 80oop SystemDictionary::_java_system_loader = NULL; 81 82bool SystemDictionary::_has_loadClassInternal = false; 83bool SystemDictionary::_has_checkPackageAccess = false; 84 85// lazily initialized klass variables 86Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 87 88 89// ---------------------------------------------------------------------------- 90// Java-level SystemLoader 91 92oop SystemDictionary::java_system_loader() { 93 return _java_system_loader; 94} 95 96void SystemDictionary::compute_java_system_loader(TRAPS) { 97 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 98 JavaValue result(T_OBJECT); 99 JavaCalls::call_static(&result, 100 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 101 vmSymbols::getSystemClassLoader_name(), 102 vmSymbols::void_classloader_signature(), 103 CHECK); 104 105 _java_system_loader = (oop)result.get_jobject(); 106} 107 108 109ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 110 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 111 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL); 112} 113 114// ---------------------------------------------------------------------------- 115// debugging 116 117#ifdef ASSERT 118 119// return true if class_name contains no '.' (internal format is '/') 120bool SystemDictionary::is_internal_format(Symbol* class_name) { 121 if (class_name != NULL) { 122 ResourceMark rm; 123 char* name = class_name->as_C_string(); 124 return strchr(name, '.') == NULL; 125 } else { 126 return true; 127 } 128} 129 130#endif 131 132// ---------------------------------------------------------------------------- 133// Parallel class loading check 134 135bool SystemDictionary::is_parallelCapable(Handle class_loader) { 136 if (UnsyncloadClass || class_loader.is_null()) return true; 137 if (AlwaysLockClassLoader) return false; 138 return java_lang_ClassLoader::parallelCapable(class_loader()); 139} 140// ---------------------------------------------------------------------------- 141// ParallelDefineClass flag does not apply to bootclass loader 142bool SystemDictionary::is_parallelDefine(Handle class_loader) { 143 if (class_loader.is_null()) return false; 144 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 145 return true; 146 } 147 return false; 148} 149 150/** 151 * Returns true if the passed class loader is the extension class loader. 152 */ 153bool SystemDictionary::is_ext_class_loader(Handle class_loader) { 154 if (class_loader.is_null()) { 155 return false; 156 } 157 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader()); 158} 159 160// ---------------------------------------------------------------------------- 161// Resolving of classes 162 163// Forwards to resolve_or_null 164 165Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 166 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 167 if (HAS_PENDING_EXCEPTION || klass == NULL) { 168 KlassHandle k_h(THREAD, klass); 169 // can return a null klass 170 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); 171 } 172 return klass; 173} 174 175Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) { 176 if (HAS_PENDING_EXCEPTION) { 177 // If we have a pending exception we forward it to the caller, unless throw_error is true, 178 // in which case we have to check whether the pending exception is a ClassNotFoundException, 179 // and if so convert it to a NoClassDefFoundError 180 // And chain the original ClassNotFoundException 181 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 182 ResourceMark rm(THREAD); 183 assert(klass_h() == NULL, "Should not have result with exception pending"); 184 Handle e(THREAD, PENDING_EXCEPTION); 185 CLEAR_PENDING_EXCEPTION; 186 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 187 } else { 188 return NULL; 189 } 190 } 191 // Class not found, throw appropriate error or exception depending on value of throw_error 192 if (klass_h() == NULL) { 193 ResourceMark rm(THREAD); 194 if (throw_error) { 195 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 196 } else { 197 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 198 } 199 } 200 return (Klass*)klass_h(); 201} 202 203 204Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 205 bool throw_error, TRAPS) 206{ 207 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 208} 209 210 211// Forwards to resolve_instance_class_or_null 212 213Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 214 assert(!THREAD->is_Compiler_thread(), 215 err_msg("can not load classes with compiler thread: class=%s, classloader=%s", 216 class_name->as_C_string(), 217 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string())); 218 if (FieldType::is_array(class_name)) { 219 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 220 } else if (FieldType::is_obj(class_name)) { 221 ResourceMark rm(THREAD); 222 // Ignore wrapping L and ;. 223 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 224 class_name->utf8_length() - 2, CHECK_NULL); 225 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL); 226 } else { 227 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 228 } 229} 230 231Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 232 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 233} 234 235// Forwards to resolve_instance_class_or_null 236 237Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 238 Handle class_loader, 239 Handle protection_domain, 240 TRAPS) { 241 assert(FieldType::is_array(class_name), "must be array"); 242 Klass* k = NULL; 243 FieldArrayInfo fd; 244 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 245 // of this call 246 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 247 if (t == T_OBJECT) { 248 // naked oop "k" is OK here -- we assign back into it 249 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 250 class_loader, 251 protection_domain, 252 CHECK_NULL); 253 if (k != NULL) { 254 k = k->array_klass(fd.dimension(), CHECK_NULL); 255 } 256 } else { 257 k = Universe::typeArrayKlassObj(t); 258 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 259 } 260 return k; 261} 262 263 264// Must be called for any super-class or super-interface resolution 265// during class definition to allow class circularity checking 266// super-interface callers: 267// parse_interfaces - for defineClass & jvmtiRedefineClasses 268// super-class callers: 269// ClassFileParser - for defineClass & jvmtiRedefineClasses 270// load_shared_class - while loading a class from shared archive 271// resolve_instance_class_or_null: 272// via: handle_parallel_super_load 273// when resolving a class that has an existing placeholder with 274// a saved superclass [i.e. a defineClass is currently in progress] 275// if another thread is trying to resolve the class, it must do 276// super-class checks on its own thread to catch class circularity 277// This last call is critical in class circularity checking for cases 278// where classloading is delegated to different threads and the 279// classloader lock is released. 280// Take the case: Base->Super->Base 281// 1. If thread T1 tries to do a defineClass of class Base 282// resolve_super_or_fail creates placeholder: T1, Base (super Super) 283// 2. resolve_instance_class_or_null does not find SD or placeholder for Super 284// so it tries to load Super 285// 3. If we load the class internally, or user classloader uses same thread 286// loadClassFromxxx or defineClass via parseClassFile Super ... 287// 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 288// 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 289// 3.4 calls resolve_super_or_fail Base 290// 3.5 finds T1,Base -> throws class circularity 291//OR 4. If T2 tries to resolve Super via defineClass Super ... 292// 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 293// 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 294// 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 295// 4.4 finds T2, Super -> throws class circularity 296// Must be called, even if superclass is null, since this is 297// where the placeholder entry is created which claims this 298// thread is loading this class/classloader. 299Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 300 Symbol* class_name, 301 Handle class_loader, 302 Handle protection_domain, 303 bool is_superclass, 304 TRAPS) { 305 // Double-check, if child class is already loaded, just return super-class,interface 306 // Don't add a placedholder if already loaded, i.e. already in system dictionary 307 // Make sure there's a placeholder for the *child* before resolving. 308 // Used as a claim that this thread is currently loading superclass/classloader 309 // Used here for ClassCircularity checks and also for heap verification 310 // (every InstanceKlass in the heap needs to be in the system dictionary 311 // or have a placeholder). 312 // Must check ClassCircularity before checking if super class is already loaded 313 // 314 // We might not already have a placeholder if this child_name was 315 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 316 // the name of the class might not be known until the stream is actually 317 // parsed. 318 // Bugs 4643874, 4715493 319 // compute_hash can have a safepoint 320 321 ClassLoaderData* loader_data = class_loader_data(class_loader); 322 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 323 int d_index = dictionary()->hash_to_index(d_hash); 324 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 325 int p_index = placeholders()->hash_to_index(p_hash); 326 // can't throw error holding a lock 327 bool child_already_loaded = false; 328 bool throw_circularity_error = false; 329 { 330 MutexLocker mu(SystemDictionary_lock, THREAD); 331 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 332 Klass* quicksuperk; 333 // to support // loading: if child done loading, just return superclass 334 // if class_name, & class_loader don't match: 335 // if initial define, SD update will give LinkageError 336 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 337 // so we don't throw an exception here. 338 // see: nsk redefclass014 & java.lang.instrument Instrument032 339 if ((childk != NULL ) && (is_superclass) && 340 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) && 341 342 ((quicksuperk->name() == class_name) && 343 (quicksuperk->class_loader() == class_loader()))) { 344 return quicksuperk; 345 } else { 346 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 347 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 348 throw_circularity_error = true; 349 } 350 } 351 if (!throw_circularity_error) { 352 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 353 } 354 } 355 if (throw_circularity_error) { 356 ResourceMark rm(THREAD); 357 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 358 } 359 360// java.lang.Object should have been found above 361 assert(class_name != NULL, "null super class for resolving"); 362 // Resolve the super class or interface, check results on return 363 Klass* superk = SystemDictionary::resolve_or_null(class_name, 364 class_loader, 365 protection_domain, 366 THREAD); 367 368 KlassHandle superk_h(THREAD, superk); 369 370 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 371 // It is no longer necessary to keep the placeholder table alive until update_dictionary 372 // or error. GC used to walk the placeholder table as strong roots. 373 // The instanceKlass is kept alive because the class loader is on the stack, 374 // which keeps the loader_data alive, as well as all instanceKlasses in 375 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 376 { 377 MutexLocker mu(SystemDictionary_lock, THREAD); 378 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 379 SystemDictionary_lock->notify_all(); 380 } 381 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 382 // can null superk 383 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); 384 } 385 386 return superk_h(); 387} 388 389void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 390 Handle class_loader, 391 Handle protection_domain, 392 TRAPS) { 393 if(!has_checkPackageAccess()) return; 394 395 // Now we have to call back to java to check if the initating class has access 396 JavaValue result(T_VOID); 397 if (TraceProtectionDomainVerification) { 398 // Print out trace information 399 tty->print_cr("Checking package access"); 400 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); 401 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); 402 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); 403 } 404 405 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 406 JavaCalls::call_special(&result, 407 class_loader, 408 system_loader, 409 vmSymbols::checkPackageAccess_name(), 410 vmSymbols::class_protectiondomain_signature(), 411 Handle(THREAD, klass->java_mirror()), 412 protection_domain, 413 THREAD); 414 415 if (TraceProtectionDomainVerification) { 416 if (HAS_PENDING_EXCEPTION) { 417 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); 418 } else { 419 tty->print_cr(" -> granted"); 420 } 421 tty->cr(); 422 } 423 424 if (HAS_PENDING_EXCEPTION) return; 425 426 // If no exception has been thrown, we have validated the protection domain 427 // Insert the protection domain of the initiating class into the set. 428 { 429 // We recalculate the entry here -- we've called out to java since 430 // the last time it was calculated. 431 ClassLoaderData* loader_data = class_loader_data(class_loader); 432 433 Symbol* kn = klass->name(); 434 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 435 int d_index = dictionary()->hash_to_index(d_hash); 436 437 MutexLocker mu(SystemDictionary_lock, THREAD); 438 { 439 // Note that we have an entry, and entries can be deleted only during GC, 440 // so we cannot allow GC to occur while we're holding this entry. 441 442 // We're using a No_Safepoint_Verifier to catch any place where we 443 // might potentially do a GC at all. 444 // Dictionary::do_unloading() asserts that classes in SD are only 445 // unloaded at a safepoint. Anonymous classes are not in SD. 446 No_Safepoint_Verifier nosafepoint; 447 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 448 protection_domain, THREAD); 449 } 450 } 451} 452 453// We only get here if this thread finds that another thread 454// has already claimed the placeholder token for the current operation, 455// but that other thread either never owned or gave up the 456// object lock 457// Waits on SystemDictionary_lock to indicate placeholder table updated 458// On return, caller must recheck placeholder table state 459// 460// We only get here if 461// 1) custom classLoader, i.e. not bootstrap classloader 462// 2) UnsyncloadClass not set 463// 3) custom classLoader has broken the class loader objectLock 464// so another thread got here in parallel 465// 466// lockObject must be held. 467// Complicated dance due to lock ordering: 468// Must first release the classloader object lock to 469// allow initial definer to complete the class definition 470// and to avoid deadlock 471// Reclaim classloader lock object with same original recursion count 472// Must release SystemDictionary_lock after notify, since 473// class loader lock must be claimed before SystemDictionary_lock 474// to prevent deadlocks 475// 476// The notify allows applications that did an untimed wait() on 477// the classloader object lock to not hang. 478void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 479 assert_lock_strong(SystemDictionary_lock); 480 481 bool calledholdinglock 482 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 483 assert(calledholdinglock,"must hold lock for notify"); 484 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 485 ObjectSynchronizer::notifyall(lockObject, THREAD); 486 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 487 SystemDictionary_lock->wait(); 488 SystemDictionary_lock->unlock(); 489 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 490 SystemDictionary_lock->lock(); 491} 492 493// If the class in is in the placeholder table, class loading is in progress 494// For cases where the application changes threads to load classes, it 495// is critical to ClassCircularity detection that we try loading 496// the superclass on the same thread internally, so we do parallel 497// super class loading here. 498// This also is critical in cases where the original thread gets stalled 499// even in non-circularity situations. 500// Note: must call resolve_super_or_fail even if null super - 501// to force placeholder entry creation for this class for circularity detection 502// Caller must check for pending exception 503// Returns non-null Klass* if other thread has completed load 504// and we are done, 505// If return null Klass* and no pending exception, the caller must load the class 506instanceKlassHandle SystemDictionary::handle_parallel_super_load( 507 Symbol* name, Symbol* superclassname, Handle class_loader, 508 Handle protection_domain, Handle lockObject, TRAPS) { 509 510 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 511 ClassLoaderData* loader_data = class_loader_data(class_loader); 512 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 513 int d_index = dictionary()->hash_to_index(d_hash); 514 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 515 int p_index = placeholders()->hash_to_index(p_hash); 516 517 // superk is not used, resolve_super called for circularity check only 518 // This code is reached in two situations. One if this thread 519 // is loading the same class twice (e.g. ClassCircularity, or 520 // java.lang.instrument). 521 // The second is if another thread started the resolve_super first 522 // and has not yet finished. 523 // In both cases the original caller will clean up the placeholder 524 // entry on error. 525 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 526 superclassname, 527 class_loader, 528 protection_domain, 529 true, 530 CHECK_(nh)); 531 532 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 533 // Serial class loaders and bootstrap classloader do wait for superclass loads 534 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 535 MutexLocker mu(SystemDictionary_lock, THREAD); 536 // Check if classloading completed while we were loading superclass or waiting 537 Klass* check = find_class(d_index, d_hash, name, loader_data); 538 if (check != NULL) { 539 // Klass is already loaded, so just return it 540 return(instanceKlassHandle(THREAD, check)); 541 } else { 542 return nh; 543 } 544 } 545 546 // must loop to both handle other placeholder updates 547 // and spurious notifications 548 bool super_load_in_progress = true; 549 PlaceholderEntry* placeholder; 550 while (super_load_in_progress) { 551 MutexLocker mu(SystemDictionary_lock, THREAD); 552 // Check if classloading completed while we were loading superclass or waiting 553 Klass* check = find_class(d_index, d_hash, name, loader_data); 554 if (check != NULL) { 555 // Klass is already loaded, so just return it 556 return(instanceKlassHandle(THREAD, check)); 557 } else { 558 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 559 if (placeholder && placeholder->super_load_in_progress() ){ 560 // Before UnsyncloadClass: 561 // We only get here if the application has released the 562 // classloader lock when another thread was in the middle of loading a 563 // superclass/superinterface for this class, and now 564 // this thread is also trying to load this class. 565 // To minimize surprises, the first thread that started to 566 // load a class should be the one to complete the loading 567 // with the classfile it initially expected. 568 // This logic has the current thread wait once it has done 569 // all the superclass/superinterface loading it can, until 570 // the original thread completes the class loading or fails 571 // If it completes we will use the resulting InstanceKlass 572 // which we will find below in the systemDictionary. 573 // We also get here for parallel bootstrap classloader 574 if (class_loader.is_null()) { 575 SystemDictionary_lock->wait(); 576 } else { 577 double_lock_wait(lockObject, THREAD); 578 } 579 } else { 580 // If not in SD and not in PH, other thread's load must have failed 581 super_load_in_progress = false; 582 } 583 } 584 } 585 return (nh); 586} 587 588 589Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) { 590 assert(name != NULL && !FieldType::is_array(name) && 591 !FieldType::is_obj(name), "invalid class name"); 592 593 // UseNewReflection 594 // Fix for 4474172; see evaluation for more details 595 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 596 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 597 598 // Do lookup to see if class already exist and the protection domain 599 // has the right access 600 // This call uses find which checks protection domain already matches 601 // All subsequent calls use find_class, and set has_loaded_class so that 602 // before we return a result we call out to java to check for valid protection domain 603 // to allow returning the Klass* and add it to the pd_set if it is valid 604 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 605 int d_index = dictionary()->hash_to_index(d_hash); 606 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 607 protection_domain, THREAD); 608 if (probe != NULL) return probe; 609 610 611 // Non-bootstrap class loaders will call out to class loader and 612 // define via jvm/jni_DefineClass which will acquire the 613 // class loader object lock to protect against multiple threads 614 // defining the class in parallel by accident. 615 // This lock must be acquired here so the waiter will find 616 // any successful result in the SystemDictionary and not attempt 617 // the define 618 // ParallelCapable Classloaders and the bootstrap classloader, 619 // or all classloaders with UnsyncloadClass do not acquire lock here 620 bool DoObjectLock = true; 621 if (is_parallelCapable(class_loader)) { 622 DoObjectLock = false; 623 } 624 625 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 626 int p_index = placeholders()->hash_to_index(p_hash); 627 628 // Class is not in SystemDictionary so we have to do loading. 629 // Make sure we are synchronized on the class loader before we proceed 630 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 631 check_loader_lock_contention(lockObject, THREAD); 632 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 633 634 // Check again (after locking) if class already exist in SystemDictionary 635 bool class_has_been_loaded = false; 636 bool super_load_in_progress = false; 637 bool havesupername = false; 638 instanceKlassHandle k; 639 PlaceholderEntry* placeholder; 640 Symbol* superclassname = NULL; 641 642 { 643 MutexLocker mu(SystemDictionary_lock, THREAD); 644 Klass* check = find_class(d_index, d_hash, name, loader_data); 645 if (check != NULL) { 646 // Klass is already loaded, so just return it 647 class_has_been_loaded = true; 648 k = instanceKlassHandle(THREAD, check); 649 } else { 650 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 651 if (placeholder && placeholder->super_load_in_progress()) { 652 super_load_in_progress = true; 653 if (placeholder->havesupername() == true) { 654 superclassname = placeholder->supername(); 655 havesupername = true; 656 } 657 } 658 } 659 } 660 661 // If the class is in the placeholder table, class loading is in progress 662 if (super_load_in_progress && havesupername==true) { 663 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 664 class_loader, protection_domain, lockObject, THREAD); 665 if (HAS_PENDING_EXCEPTION) { 666 return NULL; 667 } 668 if (!k.is_null()) { 669 class_has_been_loaded = true; 670 } 671 } 672 673 bool throw_circularity_error = false; 674 if (!class_has_been_loaded) { 675 bool load_instance_added = false; 676 677 // add placeholder entry to record loading instance class 678 // Five cases: 679 // All cases need to prevent modifying bootclasssearchpath 680 // in parallel with a classload of same classname 681 // Redefineclasses uses existence of the placeholder for the duration 682 // of the class load to prevent concurrent redefinition of not completely 683 // defined classes. 684 // case 1. traditional classloaders that rely on the classloader object lock 685 // - no other need for LOAD_INSTANCE 686 // case 2. traditional classloaders that break the classloader object lock 687 // as a deadlock workaround. Detection of this case requires that 688 // this check is done while holding the classloader object lock, 689 // and that lock is still held when calling classloader's loadClass. 690 // For these classloaders, we ensure that the first requestor 691 // completes the load and other requestors wait for completion. 692 // case 3. UnsyncloadClass - don't use objectLocker 693 // With this flag, we allow parallel classloading of a 694 // class/classloader pair 695 // case4. Bootstrap classloader - don't own objectLocker 696 // This classloader supports parallelism at the classloader level, 697 // but only allows a single load of a class/classloader pair. 698 // No performance benefit and no deadlock issues. 699 // case 5. parallelCapable user level classloaders - without objectLocker 700 // Allow parallel classloading of a class/classloader pair 701 702 { 703 MutexLocker mu(SystemDictionary_lock, THREAD); 704 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 705 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 706 if (oldprobe) { 707 // only need check_seen_thread once, not on each loop 708 // 6341374 java/lang/Instrument with -Xcomp 709 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 710 throw_circularity_error = true; 711 } else { 712 // case 1: traditional: should never see load_in_progress. 713 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 714 715 // case 4: bootstrap classloader: prevent futile classloading, 716 // wait on first requestor 717 if (class_loader.is_null()) { 718 SystemDictionary_lock->wait(); 719 } else { 720 // case 2: traditional with broken classloader lock. wait on first 721 // requestor. 722 double_lock_wait(lockObject, THREAD); 723 } 724 // Check if classloading completed while we were waiting 725 Klass* check = find_class(d_index, d_hash, name, loader_data); 726 if (check != NULL) { 727 // Klass is already loaded, so just return it 728 k = instanceKlassHandle(THREAD, check); 729 class_has_been_loaded = true; 730 } 731 // check if other thread failed to load and cleaned up 732 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 733 } 734 } 735 } 736 } 737 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 738 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 739 // LOAD_INSTANCE in parallel 740 741 if (!throw_circularity_error && !class_has_been_loaded) { 742 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 743 load_instance_added = true; 744 // For class loaders that do not acquire the classloader object lock, 745 // if they did not catch another thread holding LOAD_INSTANCE, 746 // need a check analogous to the acquire ObjectLocker/find_class 747 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 748 // one final check if the load has already completed 749 // class loaders holding the ObjectLock shouldn't find the class here 750 Klass* check = find_class(d_index, d_hash, name, loader_data); 751 if (check != NULL) { 752 // Klass is already loaded, so return it after checking/adding protection domain 753 k = instanceKlassHandle(THREAD, check); 754 class_has_been_loaded = true; 755 } 756 } 757 } 758 759 // must throw error outside of owning lock 760 if (throw_circularity_error) { 761 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 762 ResourceMark rm(THREAD); 763 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 764 } 765 766 if (!class_has_been_loaded) { 767 768 // Do actual loading 769 k = load_instance_class(name, class_loader, THREAD); 770 771 // For UnsyncloadClass only 772 // If they got a linkageError, check if a parallel class load succeeded. 773 // If it did, then for bytecode resolution the specification requires 774 // that we return the same result we did for the other thread, i.e. the 775 // successfully loaded InstanceKlass 776 // Should not get here for classloaders that support parallelism 777 // with the new cleaner mechanism, even with AllowParallelDefineClass 778 // Bootstrap goes through here to allow for an extra guarantee check 779 if (UnsyncloadClass || (class_loader.is_null())) { 780 if (k.is_null() && HAS_PENDING_EXCEPTION 781 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 782 MutexLocker mu(SystemDictionary_lock, THREAD); 783 Klass* check = find_class(d_index, d_hash, name, loader_data); 784 if (check != NULL) { 785 // Klass is already loaded, so just use it 786 k = instanceKlassHandle(THREAD, check); 787 CLEAR_PENDING_EXCEPTION; 788 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 789 } 790 } 791 } 792 793 // If everything was OK (no exceptions, no null return value), and 794 // class_loader is NOT the defining loader, do a little more bookkeeping. 795 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 796 k->class_loader() != class_loader()) { 797 798 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 799 800 // Need to check for a PENDING_EXCEPTION again; check_constraints 801 // can throw and doesn't use the CHECK macro. 802 if (!HAS_PENDING_EXCEPTION) { 803 { // Grabbing the Compile_lock prevents systemDictionary updates 804 // during compilations. 805 MutexLocker mu(Compile_lock, THREAD); 806 update_dictionary(d_index, d_hash, p_index, p_hash, 807 k, class_loader, THREAD); 808 } 809 if (JvmtiExport::should_post_class_load()) { 810 Thread *thread = THREAD; 811 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 812 JvmtiExport::post_class_load((JavaThread *) thread, k()); 813 } 814 } 815 } 816 } // load_instance_class loop 817 818 if (HAS_PENDING_EXCEPTION) { 819 // An exception, such as OOM could have happened at various places inside 820 // load_instance_class. We might have partially initialized a shared class 821 // and need to clean it up. 822 if (class_loader.is_null()) { 823 // In some cases k may be null. Let's find the shared class again. 824 instanceKlassHandle ik(THREAD, find_shared_class(name)); 825 if (ik.not_null()) { 826 if (ik->class_loader_data() == NULL) { 827 // We didn't go as far as Klass::restore_unshareable_info(), 828 // so nothing to clean up. 829 } else { 830 Klass *kk; 831 { 832 MutexLocker mu(SystemDictionary_lock, THREAD); 833 kk = find_class(name, ik->class_loader_data()); 834 } 835 if (kk != NULL) { 836 // No clean up is needed if the shared class has been entered 837 // into system dictionary, as load_shared_class() won't be called 838 // again. 839 } else { 840 // This must be done outside of the SystemDictionary_lock to 841 // avoid deadlock. 842 // 843 // Note that Klass::restore_unshareable_info (called via 844 // load_instance_class above) is also called outside 845 // of SystemDictionary_lock. Other threads are blocked from 846 // loading this class because they are waiting on the 847 // SystemDictionary_lock until this thread removes 848 // the placeholder below. 849 // 850 // This need to be re-thought when parallel-capable non-boot 851 // classloaders are supported by CDS (today they're not). 852 clean_up_shared_class(ik, class_loader, THREAD); 853 } 854 } 855 } 856 } 857 } 858 859 if (load_instance_added == true) { 860 // clean up placeholder entries for LOAD_INSTANCE success or error 861 // This brackets the SystemDictionary updates for both defining 862 // and initiating loaders 863 MutexLocker mu(SystemDictionary_lock, THREAD); 864 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 865 SystemDictionary_lock->notify_all(); 866 } 867 } 868 869 if (HAS_PENDING_EXCEPTION || k.is_null()) { 870 return NULL; 871 } 872 873#ifdef ASSERT 874 { 875 ClassLoaderData* loader_data = k->class_loader_data(); 876 MutexLocker mu(SystemDictionary_lock, THREAD); 877 Klass* kk = find_class(name, loader_data); 878 assert(kk == k(), "should be present in dictionary"); 879 } 880#endif 881 882 // return if the protection domain in NULL 883 if (protection_domain() == NULL) return k(); 884 885 // Check the protection domain has the right access 886 { 887 MutexLocker mu(SystemDictionary_lock, THREAD); 888 // Note that we have an entry, and entries can be deleted only during GC, 889 // so we cannot allow GC to occur while we're holding this entry. 890 // We're using a No_Safepoint_Verifier to catch any place where we 891 // might potentially do a GC at all. 892 // Dictionary::do_unloading() asserts that classes in SD are only 893 // unloaded at a safepoint. Anonymous classes are not in SD. 894 No_Safepoint_Verifier nosafepoint; 895 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 896 loader_data, 897 protection_domain)) { 898 return k(); 899 } 900 } 901 902 // Verify protection domain. If it fails an exception is thrown 903 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 904 905 return k(); 906} 907 908 909// This routine does not lock the system dictionary. 910// 911// Since readers don't hold a lock, we must make sure that system 912// dictionary entries are only removed at a safepoint (when only one 913// thread is running), and are added to in a safe way (all links must 914// be updated in an MT-safe manner). 915// 916// Callers should be aware that an entry could be added just after 917// _dictionary->bucket(index) is read here, so the caller will not see 918// the new entry. 919 920Klass* SystemDictionary::find(Symbol* class_name, 921 Handle class_loader, 922 Handle protection_domain, 923 TRAPS) { 924 925 // UseNewReflection 926 // The result of this call should be consistent with the result 927 // of the call to resolve_instance_class_or_null(). 928 // See evaluation 6790209 and 4474172 for more details. 929 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 930 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 931 932 if (loader_data == NULL) { 933 // If the ClassLoaderData has not been setup, 934 // then the class loader has no entries in the dictionary. 935 return NULL; 936 } 937 938 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 939 int d_index = dictionary()->hash_to_index(d_hash); 940 941 { 942 // Note that we have an entry, and entries can be deleted only during GC, 943 // so we cannot allow GC to occur while we're holding this entry. 944 // We're using a No_Safepoint_Verifier to catch any place where we 945 // might potentially do a GC at all. 946 // Dictionary::do_unloading() asserts that classes in SD are only 947 // unloaded at a safepoint. Anonymous classes are not in SD. 948 No_Safepoint_Verifier nosafepoint; 949 return dictionary()->find(d_index, d_hash, class_name, loader_data, 950 protection_domain, THREAD); 951 } 952} 953 954 955// Look for a loaded instance or array klass by name. Do not do any loading. 956// return NULL in case of error. 957Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 958 Handle class_loader, 959 Handle protection_domain, 960 TRAPS) { 961 Klass* k = NULL; 962 assert(class_name != NULL, "class name must be non NULL"); 963 964 if (FieldType::is_array(class_name)) { 965 // The name refers to an array. Parse the name. 966 // dimension and object_key in FieldArrayInfo are assigned as a 967 // side-effect of this call 968 FieldArrayInfo fd; 969 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 970 if (t != T_OBJECT) { 971 k = Universe::typeArrayKlassObj(t); 972 } else { 973 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 974 } 975 if (k != NULL) { 976 k = k->array_klass_or_null(fd.dimension()); 977 } 978 } else { 979 k = find(class_name, class_loader, protection_domain, THREAD); 980 } 981 return k; 982} 983 984// Note: this method is much like resolve_from_stream, but 985// updates no supplemental data structures. 986// TODO consolidate the two methods with a helper routine? 987Klass* SystemDictionary::parse_stream(Symbol* class_name, 988 Handle class_loader, 989 Handle protection_domain, 990 ClassFileStream* st, 991 KlassHandle host_klass, 992 GrowableArray<Handle>* cp_patches, 993 TRAPS) { 994 TempNewSymbol parsed_name = NULL; 995 996 ClassLoaderData* loader_data; 997 if (host_klass.not_null()) { 998 // Create a new CLD for anonymous class, that uses the same class loader 999 // as the host_klass 1000 assert(EnableInvokeDynamic, ""); 1001 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 1002 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 1003 loader_data->record_dependency(host_klass(), CHECK_NULL); 1004 } else { 1005 loader_data = ClassLoaderData::class_loader_data(class_loader()); 1006 } 1007 1008 // Parse the stream. Note that we do this even though this klass might 1009 // already be present in the SystemDictionary, otherwise we would not 1010 // throw potential ClassFormatErrors. 1011 // 1012 // Note: "name" is updated. 1013 1014 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1015 loader_data, 1016 protection_domain, 1017 host_klass, 1018 cp_patches, 1019 parsed_name, 1020 true, 1021 THREAD); 1022 1023 1024 if (host_klass.not_null() && k.not_null()) { 1025 assert(EnableInvokeDynamic, ""); 1026 k->set_host_klass(host_klass()); 1027 // If it's anonymous, initialize it now, since nobody else will. 1028 1029 { 1030 MutexLocker mu_r(Compile_lock, THREAD); 1031 1032 // Add to class hierarchy, initialize vtables, and do possible 1033 // deoptimizations. 1034 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1035 1036 // But, do not add to system dictionary. 1037 } 1038 1039 // Rewrite and patch constant pool here. 1040 k->link_class(CHECK_NULL); 1041 if (cp_patches != NULL) { 1042 k->constants()->patch_resolved_references(cp_patches); 1043 } 1044 k->eager_initialize(CHECK_NULL); 1045 1046 // notify jvmti 1047 if (JvmtiExport::should_post_class_load()) { 1048 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1049 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1050 } 1051 } 1052 assert(host_klass.not_null() || cp_patches == NULL, 1053 "cp_patches only found with host_klass"); 1054 1055 return k(); 1056} 1057 1058// Add a klass to the system from a stream (called by jni_DefineClass and 1059// JVM_DefineClass). 1060// Note: class_name can be NULL. In that case we do not know the name of 1061// the class until we have parsed the stream. 1062 1063Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1064 Handle class_loader, 1065 Handle protection_domain, 1066 ClassFileStream* st, 1067 bool verify, 1068 TRAPS) { 1069 1070 // Classloaders that support parallelism, e.g. bootstrap classloader, 1071 // or all classloaders with UnsyncloadClass do not acquire lock here 1072 bool DoObjectLock = true; 1073 if (is_parallelCapable(class_loader)) { 1074 DoObjectLock = false; 1075 } 1076 1077 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1078 1079 // Make sure we are synchronized on the class loader before we proceed 1080 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1081 check_loader_lock_contention(lockObject, THREAD); 1082 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1083 1084 TempNewSymbol parsed_name = NULL; 1085 1086 // Parse the stream. Note that we do this even though this klass might 1087 // already be present in the SystemDictionary, otherwise we would not 1088 // throw potential ClassFormatErrors. 1089 // 1090 // Note: "name" is updated. 1091 1092 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1093 loader_data, 1094 protection_domain, 1095 parsed_name, 1096 verify, 1097 THREAD); 1098 1099 const char* pkg = "java/"; 1100 if (!HAS_PENDING_EXCEPTION && 1101 !class_loader.is_null() && 1102 parsed_name != NULL && 1103 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1104 // It is illegal to define classes in the "java." package from 1105 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1106 ResourceMark rm(THREAD); 1107 char* name = parsed_name->as_C_string(); 1108 char* index = strrchr(name, '/'); 1109 *index = '\0'; // chop to just the package name 1110 while ((index = strchr(name, '/')) != NULL) { 1111 *index = '.'; // replace '/' with '.' in package name 1112 } 1113 const char* fmt = "Prohibited package name: %s"; 1114 size_t len = strlen(fmt) + strlen(name); 1115 char* message = NEW_RESOURCE_ARRAY(char, len); 1116 jio_snprintf(message, len, fmt, name); 1117 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1118 vmSymbols::java_lang_SecurityException(), message); 1119 } 1120 1121 if (!HAS_PENDING_EXCEPTION) { 1122 assert(parsed_name != NULL, "Sanity"); 1123 assert(class_name == NULL || class_name == parsed_name, "name mismatch"); 1124 // Verification prevents us from creating names with dots in them, this 1125 // asserts that that's the case. 1126 assert(is_internal_format(parsed_name), 1127 "external class name format used internally"); 1128 1129 // Add class just loaded 1130 // If a class loader supports parallel classloading handle parallel define requests 1131 // find_or_define_instance_class may return a different InstanceKlass 1132 if (is_parallelCapable(class_loader)) { 1133 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); 1134 } else { 1135 define_instance_class(k, THREAD); 1136 } 1137 } 1138 1139 // Make sure we have an entry in the SystemDictionary on success 1140 debug_only( { 1141 if (!HAS_PENDING_EXCEPTION) { 1142 assert(parsed_name != NULL, "parsed_name is still null?"); 1143 Symbol* h_name = k->name(); 1144 ClassLoaderData *defining_loader_data = k->class_loader_data(); 1145 1146 MutexLocker mu(SystemDictionary_lock, THREAD); 1147 1148 Klass* check = find_class(parsed_name, loader_data); 1149 assert(check == k(), "should be present in the dictionary"); 1150 1151 Klass* check2 = find_class(h_name, defining_loader_data); 1152 assert(check == check2, "name inconsistancy in SystemDictionary"); 1153 } 1154 } ); 1155 1156 return k(); 1157} 1158 1159 1160void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1161 int number_of_entries) { 1162 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1163 "bad shared dictionary size."); 1164 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1165} 1166 1167 1168// If there is a shared dictionary, then find the entry for the 1169// given shared system class, if any. 1170 1171Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1172 if (shared_dictionary() != NULL) { 1173 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1174 int d_index = shared_dictionary()->hash_to_index(d_hash); 1175 1176 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1177 } else { 1178 return NULL; 1179 } 1180} 1181 1182 1183// Load a class from the shared spaces (found through the shared system 1184// dictionary). Force the superclass and all interfaces to be loaded. 1185// Update the class definition to include sibling classes and no 1186// subclasses (yet). [Classes in the shared space are not part of the 1187// object hierarchy until loaded.] 1188 1189instanceKlassHandle SystemDictionary::load_shared_class( 1190 Symbol* class_name, Handle class_loader, TRAPS) { 1191 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1192 return load_shared_class(ik, class_loader, THREAD); 1193} 1194 1195instanceKlassHandle SystemDictionary::load_shared_class( 1196 instanceKlassHandle ik, Handle class_loader, TRAPS) { 1197 assert(class_loader.is_null(), "non-null classloader for shared class?"); 1198 if (ik.not_null()) { 1199 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1200 Symbol* class_name = ik->name(); 1201 1202 // Found the class, now load the superclass and interfaces. If they 1203 // are shared, add them to the main system dictionary and reset 1204 // their hierarchy references (supers, subs, and interfaces). 1205 1206 if (ik->super() != NULL) { 1207 Symbol* cn = ik->super()->name(); 1208 resolve_super_or_fail(class_name, cn, 1209 class_loader, Handle(), true, CHECK_(nh)); 1210 } 1211 1212 Array<Klass*>* interfaces = ik->local_interfaces(); 1213 int num_interfaces = interfaces->length(); 1214 for (int index = 0; index < num_interfaces; index++) { 1215 Klass* k = interfaces->at(index); 1216 1217 // Note: can not use InstanceKlass::cast here because 1218 // interfaces' InstanceKlass's C++ vtbls haven't been 1219 // reinitialized yet (they will be once the interface classes 1220 // are loaded) 1221 Symbol* name = k->name(); 1222 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); 1223 } 1224 1225 // Adjust methods to recover missing data. They need addresses for 1226 // interpreter entry points and their default native method address 1227 // must be reset. 1228 1229 // Updating methods must be done under a lock so multiple 1230 // threads don't update these in parallel 1231 // Shared classes are all currently loaded by the bootstrap 1232 // classloader, so this will never cause a deadlock on 1233 // a custom class loader lock. 1234 1235 { 1236 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1237 check_loader_lock_contention(lockObject, THREAD); 1238 ObjectLocker ol(lockObject, THREAD, true); 1239 ik->restore_unshareable_info(CHECK_(nh)); 1240 } 1241 1242 if (TraceClassLoading) { 1243 ResourceMark rm; 1244 tty->print("[Loaded %s", ik->external_name()); 1245 tty->print(" from shared objects file"); 1246 tty->print_cr("]"); 1247 } 1248 // notify a class loaded from shared object 1249 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()), 1250 true /* shared class */); 1251 } 1252 return ik; 1253} 1254 1255void SystemDictionary::clean_up_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS) { 1256 // Updating methods must be done under a lock so multiple 1257 // threads don't update these in parallel 1258 // Shared classes are all currently loaded by the bootstrap 1259 // classloader, so this will never cause a deadlock on 1260 // a custom class loader lock. 1261 { 1262 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1263 check_loader_lock_contention(lockObject, THREAD); 1264 ObjectLocker ol(lockObject, THREAD, true); 1265 ik->remove_unshareable_info(); 1266 } 1267} 1268 1269instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1270 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1271 if (class_loader.is_null()) { 1272 1273 // Search the shared system dictionary for classes preloaded into the 1274 // shared spaces. 1275 instanceKlassHandle k; 1276 { 1277 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1278 k = load_shared_class(class_name, class_loader, THREAD); 1279 } 1280 1281 if (k.is_null()) { 1282 // Use VM class loader 1283 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1284 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); 1285 } 1286 1287 // find_or_define_instance_class may return a different InstanceKlass 1288 if (!k.is_null()) { 1289 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1290 } 1291 return k; 1292 } else { 1293 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1294 ResourceMark rm(THREAD); 1295 1296 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1297 JavaThread* jt = (JavaThread*) THREAD; 1298 1299 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1300 ClassLoader::perf_app_classload_selftime(), 1301 ClassLoader::perf_app_classload_count(), 1302 jt->get_thread_stat()->perf_recursion_counts_addr(), 1303 jt->get_thread_stat()->perf_timers_addr(), 1304 PerfClassTraceTime::CLASS_LOAD); 1305 1306 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1307 // Translate to external class name format, i.e., convert '/' chars to '.' 1308 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1309 1310 JavaValue result(T_OBJECT); 1311 1312 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1313 1314 // Call public unsynchronized loadClass(String) directly for all class loaders 1315 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1316 // acquire a class-name based lock rather than the class loader object lock. 1317 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1318 // so the call to loadClassInternal() was not required. 1319 // 1320 // UnsyncloadClass flag means both call loadClass(String) and do 1321 // not acquire the class loader lock even for class loaders that are 1322 // not parallelCapable. This was a risky transitional 1323 // flag for diagnostic purposes only. It is risky to call 1324 // custom class loaders without synchronization. 1325 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1326 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1327 // Do NOT assume this will be supported in future releases. 1328 // 1329 // Added MustCallLoadClassInternal in case we discover in the field 1330 // a customer that counts on this call 1331 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1332 JavaCalls::call_special(&result, 1333 class_loader, 1334 spec_klass, 1335 vmSymbols::loadClassInternal_name(), 1336 vmSymbols::string_class_signature(), 1337 string, 1338 CHECK_(nh)); 1339 } else { 1340 JavaCalls::call_virtual(&result, 1341 class_loader, 1342 spec_klass, 1343 vmSymbols::loadClass_name(), 1344 vmSymbols::string_class_signature(), 1345 string, 1346 CHECK_(nh)); 1347 } 1348 1349 assert(result.get_type() == T_OBJECT, "just checking"); 1350 oop obj = (oop) result.get_jobject(); 1351 1352 // Primitive classes return null since forName() can not be 1353 // used to obtain any of the Class objects representing primitives or void 1354 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1355 instanceKlassHandle k = 1356 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1357 // For user defined Java class loaders, check that the name returned is 1358 // the same as that requested. This check is done for the bootstrap 1359 // loader when parsing the class file. 1360 if (class_name == k->name()) { 1361 return k; 1362 } 1363 } 1364 // Class is not found or has the wrong name, return NULL 1365 return nh; 1366 } 1367} 1368 1369void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1370 1371 ClassLoaderData* loader_data = k->class_loader_data(); 1372 Handle class_loader_h(THREAD, loader_data->class_loader()); 1373 1374 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){} 1375 1376 // for bootstrap and other parallel classloaders don't acquire lock, 1377 // use placeholder token 1378 // If a parallelCapable class loader calls define_instance_class instead of 1379 // find_or_define_instance_class to get here, we have a timing 1380 // hole with systemDictionary updates and check_constraints 1381 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1382 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1383 compute_loader_lock_object(class_loader_h, THREAD)), 1384 "define called without lock"); 1385 } 1386 1387 // Check class-loading constraints. Throw exception if violation is detected. 1388 // Grabs and releases SystemDictionary_lock 1389 // The check_constraints/find_class call and update_dictionary sequence 1390 // must be "atomic" for a specific class/classloader pair so we never 1391 // define two different instanceKlasses for that class/classloader pair. 1392 // Existing classloaders will call define_instance_class with the 1393 // classloader lock held 1394 // Parallel classloaders will call find_or_define_instance_class 1395 // which will require a token to perform the define class 1396 Symbol* name_h = k->name(); 1397 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1398 int d_index = dictionary()->hash_to_index(d_hash); 1399 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1400 1401 // Register class just loaded with class loader (placed in Vector) 1402 // Note we do this before updating the dictionary, as this can 1403 // fail with an OutOfMemoryError (if it does, we will *not* put this 1404 // class in the dictionary and will not update the class hierarchy). 1405 // JVMTI FollowReferences needs to find the classes this way. 1406 if (k->class_loader() != NULL) { 1407 methodHandle m(THREAD, Universe::loader_addClass_method()); 1408 JavaValue result(T_VOID); 1409 JavaCallArguments args(class_loader_h); 1410 args.push_oop(Handle(THREAD, k->java_mirror())); 1411 JavaCalls::call(&result, m, &args, CHECK); 1412 } 1413 1414 // Add the new class. We need recompile lock during update of CHA. 1415 { 1416 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1417 int p_index = placeholders()->hash_to_index(p_hash); 1418 1419 MutexLocker mu_r(Compile_lock, THREAD); 1420 1421 // Add to class hierarchy, initialize vtables, and do possible 1422 // deoptimizations. 1423 add_to_hierarchy(k, CHECK); // No exception, but can block 1424 1425 // Add to systemDictionary - so other classes can see it. 1426 // Grabs and releases SystemDictionary_lock 1427 update_dictionary(d_index, d_hash, p_index, p_hash, 1428 k, class_loader_h, THREAD); 1429 } 1430 k->eager_initialize(THREAD); 1431 1432 // notify jvmti 1433 if (JvmtiExport::should_post_class_load()) { 1434 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1435 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1436 1437 } 1438} 1439 1440// Support parallel classloading 1441// All parallel class loaders, including bootstrap classloader 1442// lock a placeholder entry for this class/class_loader pair 1443// to allow parallel defines of different classes for this class loader 1444// With AllowParallelDefine flag==true, in case they do not synchronize around 1445// FindLoadedClass/DefineClass, calls, we check for parallel 1446// loading for them, wait if a defineClass is in progress 1447// and return the initial requestor's results 1448// This flag does not apply to the bootstrap classloader. 1449// With AllowParallelDefine flag==false, call through to define_instance_class 1450// which will throw LinkageError: duplicate class definition. 1451// False is the requested default. 1452// For better performance, the class loaders should synchronize 1453// findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1454// potentially waste time reading and parsing the bytestream. 1455// Note: VM callers should ensure consistency of k/class_name,class_loader 1456instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1457 1458 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1459 Symbol* name_h = k->name(); // passed in class_name may be null 1460 ClassLoaderData* loader_data = class_loader_data(class_loader); 1461 1462 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1463 int d_index = dictionary()->hash_to_index(d_hash); 1464 1465// Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1466 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1467 int p_index = placeholders()->hash_to_index(p_hash); 1468 PlaceholderEntry* probe; 1469 1470 { 1471 MutexLocker mu(SystemDictionary_lock, THREAD); 1472 // First check if class already defined 1473 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1474 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1475 if (check != NULL) { 1476 return(instanceKlassHandle(THREAD, check)); 1477 } 1478 } 1479 1480 // Acquire define token for this class/classloader 1481 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1482 // Wait if another thread defining in parallel 1483 // All threads wait - even those that will throw duplicate class: otherwise 1484 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1485 // if other thread has not finished updating dictionary 1486 while (probe->definer() != NULL) { 1487 SystemDictionary_lock->wait(); 1488 } 1489 // Only special cases allow parallel defines and can use other thread's results 1490 // Other cases fall through, and may run into duplicate defines 1491 // caught by finding an entry in the SystemDictionary 1492 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1493 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1494 SystemDictionary_lock->notify_all(); 1495#ifdef ASSERT 1496 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1497 assert(check != NULL, "definer missed recording success"); 1498#endif 1499 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1500 } else { 1501 // This thread will define the class (even if earlier thread tried and had an error) 1502 probe->set_definer(THREAD); 1503 } 1504 } 1505 1506 define_instance_class(k, THREAD); 1507 1508 Handle linkage_exception = Handle(); // null handle 1509 1510 // definer must notify any waiting threads 1511 { 1512 MutexLocker mu(SystemDictionary_lock, THREAD); 1513 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1514 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1515 if (probe != NULL) { 1516 if (HAS_PENDING_EXCEPTION) { 1517 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1518 CLEAR_PENDING_EXCEPTION; 1519 } else { 1520 probe->set_instance_klass(k()); 1521 } 1522 probe->set_definer(NULL); 1523 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1524 SystemDictionary_lock->notify_all(); 1525 } 1526 } 1527 1528 // Can't throw exception while holding lock due to rank ordering 1529 if (linkage_exception() != NULL) { 1530 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1531 } 1532 1533 return k; 1534} 1535Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1536 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1537 if (class_loader.is_null()) { 1538 return Handle(THREAD, _system_loader_lock_obj); 1539 } else { 1540 return class_loader; 1541 } 1542} 1543 1544// This method is added to check how often we have to wait to grab loader 1545// lock. The results are being recorded in the performance counters defined in 1546// ClassLoader::_sync_systemLoaderLockContentionRate and 1547// ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1548void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1549 if (!UsePerfData) { 1550 return; 1551 } 1552 1553 assert(!loader_lock.is_null(), "NULL lock object"); 1554 1555 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1556 == ObjectSynchronizer::owner_other) { 1557 // contention will likely happen, so increment the corresponding 1558 // contention counter. 1559 if (loader_lock() == _system_loader_lock_obj) { 1560 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1561 } else { 1562 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1563 } 1564 } 1565} 1566 1567// ---------------------------------------------------------------------------- 1568// Lookup 1569 1570Klass* SystemDictionary::find_class(int index, unsigned int hash, 1571 Symbol* class_name, 1572 ClassLoaderData* loader_data) { 1573 assert_locked_or_safepoint(SystemDictionary_lock); 1574 assert (index == dictionary()->index_for(class_name, loader_data), 1575 "incorrect index?"); 1576 1577 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1578 return k; 1579} 1580 1581 1582// Basic find on classes in the midst of being loaded 1583Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1584 ClassLoaderData* loader_data) { 1585 assert_locked_or_safepoint(SystemDictionary_lock); 1586 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1587 int p_index = placeholders()->hash_to_index(p_hash); 1588 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1589} 1590 1591 1592// Used for assertions and verification only 1593Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1594 #ifndef ASSERT 1595 guarantee(VerifyBeforeGC || 1596 VerifyDuringGC || 1597 VerifyBeforeExit || 1598 VerifyAfterGC, "too expensive"); 1599 #endif 1600 assert_locked_or_safepoint(SystemDictionary_lock); 1601 1602 // First look in the loaded class array 1603 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1604 int d_index = dictionary()->hash_to_index(d_hash); 1605 return find_class(d_index, d_hash, class_name, loader_data); 1606} 1607 1608 1609// Get the next class in the diictionary. 1610Klass* SystemDictionary::try_get_next_class() { 1611 return dictionary()->try_get_next_class(); 1612} 1613 1614 1615// ---------------------------------------------------------------------------- 1616// Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1617// is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1618// before a new class is used. 1619 1620void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1621 assert(k.not_null(), "just checking"); 1622 assert_locked_or_safepoint(Compile_lock); 1623 1624 // Link into hierachy. Make sure the vtables are initialized before linking into 1625 k->append_to_sibling_list(); // add to superklass/sibling list 1626 k->process_interfaces(THREAD); // handle all "implements" declarations 1627 k->set_init_state(InstanceKlass::loaded); 1628 // Now flush all code that depended on old class hierarchy. 1629 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1630 // Also, first reinitialize vtable because it may have gotten out of synch 1631 // while the new class wasn't connected to the class hierarchy. 1632 Universe::flush_dependents_on(k); 1633} 1634 1635 1636// ---------------------------------------------------------------------------- 1637// GC support 1638 1639// Following roots during mark-sweep is separated in two phases. 1640// 1641// The first phase follows preloaded classes and all other system 1642// classes, since these will never get unloaded anyway. 1643// 1644// The second phase removes (unloads) unreachable classes from the 1645// system dictionary and follows the remaining classes' contents. 1646 1647void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1648 blk->do_oop(&_java_system_loader); 1649 blk->do_oop(&_system_loader_lock_obj); 1650 1651 dictionary()->always_strong_oops_do(blk); 1652 1653 // Visit extra methods 1654 invoke_method_table()->oops_do(blk); 1655} 1656 1657void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1658 // Follow all system classes and temporary placeholders in dictionary 1659 dictionary()->always_strong_classes_do(closure); 1660 1661 // Placeholders. These represent classes we're actively loading. 1662 placeholders()->classes_do(closure); 1663} 1664 1665// Calculate a "good" systemdictionary size based 1666// on predicted or current loaded classes count 1667int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1668 int newsize = _old_default_sdsize; 1669 if ((classcount > 0) && !DumpSharedSpaces) { 1670 int desiredsize = classcount/_average_depth_goal; 1671 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1672 newsize = _primelist[++_sdgeneration]) { 1673 if (desiredsize <= newsize) { 1674 break; 1675 } 1676 } 1677 } 1678 return newsize; 1679} 1680// Assumes classes in the SystemDictionary are only unloaded at a safepoint 1681// Note: anonymous classes are not in the SD. 1682bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { 1683 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1684 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive); 1685 bool unloading_occurred = false; 1686 if (has_dead_loaders) { 1687 unloading_occurred = dictionary()->do_unloading(); 1688 constraints()->purge_loader_constraints(); 1689 resolution_errors()->purge_resolution_errors(); 1690} 1691 return unloading_occurred; 1692} 1693 1694void SystemDictionary::oops_do(OopClosure* f) { 1695 f->do_oop(&_java_system_loader); 1696 f->do_oop(&_system_loader_lock_obj); 1697 1698 // Adjust dictionary 1699 dictionary()->oops_do(f); 1700 1701 // Visit extra methods 1702 invoke_method_table()->oops_do(f); 1703} 1704 1705// Extended Class redefinition support. 1706// If one of these classes is replaced, we need to replace it in these places. 1707// KlassClosure::do_klass should take the address of a class but we can 1708// change that later. 1709void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 1710 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 1711 f->do_klass(_well_known_klasses[k]); 1712 } 1713 1714 { 1715 for (int i = 0; i < T_VOID+1; i++) { 1716 if (_box_klasses[i] != NULL) { 1717 assert(i >= T_BOOLEAN, "checking"); 1718 f->do_klass(_box_klasses[i]); 1719 } 1720 } 1721 } 1722 1723 FilteredFieldsMap::classes_do(f); 1724} 1725 1726void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 1727 f->do_klass(_abstract_ownable_synchronizer_klass); 1728} 1729 1730// Just the classes from defining class loaders 1731// Don't iterate over placeholders 1732void SystemDictionary::classes_do(void f(Klass*)) { 1733 dictionary()->classes_do(f); 1734} 1735 1736// Added for initialize_itable_for_klass 1737// Just the classes from defining class loaders 1738// Don't iterate over placeholders 1739void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 1740 dictionary()->classes_do(f, CHECK); 1741} 1742 1743// All classes, and their class loaders 1744// Don't iterate over placeholders 1745void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 1746 dictionary()->classes_do(f); 1747} 1748 1749// All classes, and their class loaders 1750// (added for helpers that use HandleMarks and ResourceMarks) 1751// Don't iterate over placeholders 1752void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) { 1753 dictionary()->classes_do(f, CHECK); 1754} 1755 1756void SystemDictionary::placeholders_do(void f(Symbol*)) { 1757 placeholders()->entries_do(f); 1758} 1759 1760void SystemDictionary::methods_do(void f(Method*)) { 1761 dictionary()->methods_do(f); 1762 invoke_method_table()->methods_do(f); 1763} 1764 1765// ---------------------------------------------------------------------------- 1766// Lazily load klasses 1767 1768void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1769 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); 1770 1771 // if multiple threads calling this function, only one thread will load 1772 // the class. The other threads will find the loaded version once the 1773 // class is loaded. 1774 Klass* aos = _abstract_ownable_synchronizer_klass; 1775 if (aos == NULL) { 1776 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1777 // Force a fence to prevent any read before the write completes 1778 OrderAccess::fence(); 1779 _abstract_ownable_synchronizer_klass = k; 1780 } 1781} 1782 1783// ---------------------------------------------------------------------------- 1784// Initialization 1785 1786void SystemDictionary::initialize(TRAPS) { 1787 // Allocate arrays 1788 assert(dictionary() == NULL, 1789 "SystemDictionary should only be initialized once"); 1790 _sdgeneration = 0; 1791 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 1792 _placeholders = new PlaceholderTable(_nof_buckets); 1793 _number_of_modifications = 0; 1794 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1795 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1796 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1797 1798 // Allocate private object used as system class loader lock 1799 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1800 // Initialize basic classes 1801 initialize_preloaded_classes(CHECK); 1802} 1803 1804// Compact table of directions on the initialization of klasses: 1805static const short wk_init_info[] = { 1806 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1807 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1808 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1809 | (int)SystemDictionary::option ), 1810 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1811 #undef WK_KLASS_INIT_INFO 1812 0 1813}; 1814 1815bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 1816 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1817 int info = wk_init_info[id - FIRST_WKID]; 1818 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1819 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1820 Klass** klassp = &_well_known_klasses[id]; 1821 bool must_load = (init_opt < SystemDictionary::Opt); 1822 if ((*klassp) == NULL) { 1823 if (must_load) { 1824 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class 1825 } else { 1826 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass 1827 } 1828 } 1829 return ((*klassp) != NULL); 1830} 1831 1832void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1833 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1834 for (int id = (int)start_id; id < (int)limit_id; id++) { 1835 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1836 int info = wk_init_info[id - FIRST_WKID]; 1837 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1838 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1839 1840 initialize_wk_klass((WKID)id, opt, CHECK); 1841 } 1842 1843 // move the starting value forward to the limit: 1844 start_id = limit_id; 1845} 1846 1847void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1848 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 1849 // Preload commonly used klasses 1850 WKID scan = FIRST_WKID; 1851 // first do Object, then String, Class 1852 if (UseSharedSpaces) { 1853 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1854 // Initialize the constant pool for the Object_class 1855 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 1856 ik->constants()->restore_unshareable_info(CHECK); 1857 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1858 } else { 1859 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1860 } 1861 1862 // Calculate offsets for String and Class classes since they are loaded and 1863 // can be used after this point. 1864 java_lang_String::compute_offsets(); 1865 java_lang_Class::compute_offsets(); 1866 1867 // Fixup mirrors for classes loaded before java.lang.Class. 1868 // These calls iterate over the objects currently in the perm gen 1869 // so calling them at this point is matters (not before when there 1870 // are fewer objects and not later after there are more objects 1871 // in the perm gen. 1872 Universe::initialize_basic_type_mirrors(CHECK); 1873 Universe::fixup_mirrors(CHECK); 1874 1875 // do a bunch more: 1876 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 1877 1878 // Preload ref klasses and set reference types 1879 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 1880 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 1881 1882 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 1883 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 1884 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 1885 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 1886 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 1887 1888 // JSR 292 classes 1889 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 1890 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 1891 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 1892 if (EnableInvokeDynamic) { 1893 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 1894 } else { 1895 // Skip the JSR 292 classes, if not enabled. 1896 scan = WKID(jsr292_group_end + 1); 1897 } 1898 1899 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); 1900 1901 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 1902 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 1903 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 1904 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 1905 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 1906 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 1907 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 1908 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 1909 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 1910 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 1911 1912 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 1913 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 1914 _has_loadClassInternal = (method != NULL); 1915 } 1916 { // Compute whether we should use checkPackageAccess or NOT 1917 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 1918 _has_checkPackageAccess = (method != NULL); 1919 } 1920} 1921 1922// Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 1923// If so, returns the basic type it holds. If not, returns T_OBJECT. 1924BasicType SystemDictionary::box_klass_type(Klass* k) { 1925 assert(k != NULL, ""); 1926 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 1927 if (_box_klasses[i] == k) 1928 return (BasicType)i; 1929 } 1930 return T_OBJECT; 1931} 1932 1933// Constraints on class loaders. The details of the algorithm can be 1934// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 1935// Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 1936// that the system dictionary needs to maintain a set of contraints that 1937// must be satisfied by all classes in the dictionary. 1938// if defining is true, then LinkageError if already in systemDictionary 1939// if initiating loader, then ok if InstanceKlass matches existing entry 1940 1941void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 1942 instanceKlassHandle k, 1943 Handle class_loader, bool defining, 1944 TRAPS) { 1945 const char *linkage_error = NULL; 1946 { 1947 Symbol* name = k->name(); 1948 ClassLoaderData *loader_data = class_loader_data(class_loader); 1949 1950 MutexLocker mu(SystemDictionary_lock, THREAD); 1951 1952 Klass* check = find_class(d_index, d_hash, name, loader_data); 1953 if (check != (Klass*)NULL) { 1954 // if different InstanceKlass - duplicate class definition, 1955 // else - ok, class loaded by a different thread in parallel, 1956 // we should only have found it if it was done loading and ok to use 1957 // system dictionary only holds instance classes, placeholders 1958 // also holds array classes 1959 1960 assert(check->oop_is_instance(), "noninstance in systemdictionary"); 1961 if ((defining == true) || (k() != check)) { 1962 linkage_error = "loader (instance of %s): attempted duplicate class " 1963 "definition for name: \"%s\""; 1964 } else { 1965 return; 1966 } 1967 } 1968 1969#ifdef ASSERT 1970 Symbol* ph_check = find_placeholder(name, loader_data); 1971 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 1972#endif 1973 1974 if (linkage_error == NULL) { 1975 if (constraints()->check_or_update(k, class_loader, name) == false) { 1976 linkage_error = "loader constraint violation: loader (instance of %s)" 1977 " previously initiated loading for a different type with name \"%s\""; 1978 } 1979 } 1980 } 1981 1982 // Throw error now if needed (cannot throw while holding 1983 // SystemDictionary_lock because of rank ordering) 1984 1985 if (linkage_error) { 1986 ResourceMark rm(THREAD); 1987 const char* class_loader_name = loader_name(class_loader()); 1988 char* type_name = k->name()->as_C_string(); 1989 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + 1990 strlen(type_name); 1991 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 1992 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); 1993 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 1994 } 1995} 1996 1997 1998// Update system dictionary - done after check_constraint and add_to_hierachy 1999// have been called. 2000void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 2001 int p_index, unsigned int p_hash, 2002 instanceKlassHandle k, 2003 Handle class_loader, 2004 TRAPS) { 2005 // Compile_lock prevents systemDictionary updates during compilations 2006 assert_locked_or_safepoint(Compile_lock); 2007 Symbol* name = k->name(); 2008 ClassLoaderData *loader_data = class_loader_data(class_loader); 2009 2010 { 2011 MutexLocker mu1(SystemDictionary_lock, THREAD); 2012 2013 // See whether biased locking is enabled and if so set it for this 2014 // klass. 2015 // Note that this must be done past the last potential blocking 2016 // point / safepoint. We enable biased locking lazily using a 2017 // VM_Operation to iterate the SystemDictionary and installing the 2018 // biasable mark word into each InstanceKlass's prototype header. 2019 // To avoid race conditions where we accidentally miss enabling the 2020 // optimization for one class in the process of being added to the 2021 // dictionary, we must not safepoint after the test of 2022 // BiasedLocking::enabled(). 2023 if (UseBiasedLocking && BiasedLocking::enabled()) { 2024 // Set biased locking bit for all loaded classes; it will be 2025 // cleared if revocation occurs too often for this type 2026 // NOTE that we must only do this when the class is initally 2027 // defined, not each time it is referenced from a new class loader 2028 if (k->class_loader() == class_loader()) { 2029 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2030 } 2031 } 2032 2033 // Assign a classid if one has not already been assigned. The 2034 // counter does not need to be atomically incremented since this 2035 // is only done while holding the SystemDictionary_lock. 2036 // All loaded classes get a unique ID. 2037 TRACE_INIT_ID(k); 2038 2039 // Make a new system dictionary entry. 2040 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2041 if (sd_check == NULL) { 2042 dictionary()->add_klass(name, loader_data, k); 2043 notice_modification(); 2044 } 2045#ifdef ASSERT 2046 sd_check = find_class(d_index, d_hash, name, loader_data); 2047 assert (sd_check != NULL, "should have entry in system dictionary"); 2048 // Note: there may be a placeholder entry: for circularity testing 2049 // or for parallel defines 2050#endif 2051 SystemDictionary_lock->notify_all(); 2052 } 2053} 2054 2055 2056// Try to find a class name using the loader constraints. The 2057// loader constraints might know about a class that isn't fully loaded 2058// yet and these will be ignored. 2059Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2060 Symbol* class_name, Handle class_loader, TRAPS) { 2061 2062 // First see if it has been loaded directly. 2063 // Force the protection domain to be null. (This removes protection checks.) 2064 Handle no_protection_domain; 2065 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2066 no_protection_domain, CHECK_NULL); 2067 if (klass != NULL) 2068 return klass; 2069 2070 // Now look to see if it has been loaded elsewhere, and is subject to 2071 // a loader constraint that would require this loader to return the 2072 // klass that is already loaded. 2073 if (FieldType::is_array(class_name)) { 2074 // For array classes, their Klass*s are not kept in the 2075 // constraint table. The element Klass*s are. 2076 FieldArrayInfo fd; 2077 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2078 if (t != T_OBJECT) { 2079 klass = Universe::typeArrayKlassObj(t); 2080 } else { 2081 MutexLocker mu(SystemDictionary_lock, THREAD); 2082 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2083 } 2084 // If element class already loaded, allocate array klass 2085 if (klass != NULL) { 2086 klass = klass->array_klass_or_null(fd.dimension()); 2087 } 2088 } else { 2089 MutexLocker mu(SystemDictionary_lock, THREAD); 2090 // Non-array classes are easy: simply check the constraint table. 2091 klass = constraints()->find_constrained_klass(class_name, class_loader); 2092 } 2093 2094 return klass; 2095} 2096 2097 2098bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2099 Handle class_loader1, 2100 Handle class_loader2, 2101 Thread* THREAD) { 2102 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2103 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2104 2105 Symbol* constraint_name = NULL; 2106 if (!FieldType::is_array(class_name)) { 2107 constraint_name = class_name; 2108 } else { 2109 // For array classes, their Klass*s are not kept in the 2110 // constraint table. The element classes are. 2111 FieldArrayInfo fd; 2112 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2113 // primitive types always pass 2114 if (t != T_OBJECT) { 2115 return true; 2116 } else { 2117 constraint_name = fd.object_key(); 2118 } 2119 } 2120 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2121 int d_index1 = dictionary()->hash_to_index(d_hash1); 2122 2123 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2124 int d_index2 = dictionary()->hash_to_index(d_hash2); 2125 { 2126 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2127 2128 // Better never do a GC while we're holding these oops 2129 No_Safepoint_Verifier nosafepoint; 2130 2131 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2132 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2133 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2134 klass2, class_loader2); 2135 } 2136} 2137 2138// Add entry to resolution error table to record the error when the first 2139// attempt to resolve a reference to a class has failed. 2140void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) { 2141 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2142 int index = resolution_errors()->hash_to_index(hash); 2143 { 2144 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2145 resolution_errors()->add_entry(index, hash, pool, which, error); 2146 } 2147} 2148 2149// Delete a resolution error for RedefineClasses for a constant pool is going away 2150void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2151 resolution_errors()->delete_entry(pool); 2152} 2153 2154// Lookup resolution error table. Returns error if found, otherwise NULL. 2155Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { 2156 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2157 int index = resolution_errors()->hash_to_index(hash); 2158 { 2159 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2160 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2161 return (entry != NULL) ? entry->error() : (Symbol*)NULL; 2162 } 2163} 2164 2165 2166// Signature constraints ensure that callers and callees agree about 2167// the meaning of type names in their signatures. This routine is the 2168// intake for constraints. It collects them from several places: 2169// 2170// * LinkResolver::resolve_method (if check_access is true) requires 2171// that the resolving class (the caller) and the defining class of 2172// the resolved method (the callee) agree on each type in the 2173// method's signature. 2174// 2175// * LinkResolver::resolve_interface_method performs exactly the same 2176// checks. 2177// 2178// * LinkResolver::resolve_field requires that the constant pool 2179// attempting to link to a field agree with the field's defining 2180// class about the type of the field signature. 2181// 2182// * klassVtable::initialize_vtable requires that, when a class 2183// overrides a vtable entry allocated by a superclass, that the 2184// overriding method (i.e., the callee) agree with the superclass 2185// on each type in the method's signature. 2186// 2187// * klassItable::initialize_itable requires that, when a class fills 2188// in its itables, for each non-abstract method installed in an 2189// itable, the method (i.e., the callee) agree with the interface 2190// on each type in the method's signature. 2191// 2192// All those methods have a boolean (check_access, checkconstraints) 2193// which turns off the checks. This is used from specialized contexts 2194// such as bootstrapping, dumping, and debugging. 2195// 2196// No direct constraint is placed between the class and its 2197// supertypes. Constraints are only placed along linked relations 2198// between callers and callees. When a method overrides or implements 2199// an abstract method in a supertype (superclass or interface), the 2200// constraints are placed as if the supertype were the caller to the 2201// overriding method. (This works well, since callers to the 2202// supertype have already established agreement between themselves and 2203// the supertype.) As a result of all this, a class can disagree with 2204// its supertype about the meaning of a type name, as long as that 2205// class neither calls a relevant method of the supertype, nor is 2206// called (perhaps via an override) from the supertype. 2207// 2208// 2209// SystemDictionary::check_signature_loaders(sig, l1, l2) 2210// 2211// Make sure all class components (including arrays) in the given 2212// signature will be resolved to the same class in both loaders. 2213// Returns the name of the type that failed a loader constraint check, or 2214// NULL if no constraint failed. No exception except OOME is thrown. 2215// Arrays are not added to the loader constraint table, their elements are. 2216Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2217 Handle loader1, Handle loader2, 2218 bool is_method, TRAPS) { 2219 // Nothing to do if loaders are the same. 2220 if (loader1() == loader2()) { 2221 return NULL; 2222 } 2223 2224 SignatureStream sig_strm(signature, is_method); 2225 while (!sig_strm.is_done()) { 2226 if (sig_strm.is_object()) { 2227 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2228 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2229 return sig; 2230 } 2231 } 2232 sig_strm.next(); 2233 } 2234 return NULL; 2235} 2236 2237 2238methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2239 Symbol* signature, 2240 TRAPS) { 2241 methodHandle empty; 2242 assert(EnableInvokeDynamic, ""); 2243 assert(MethodHandles::is_signature_polymorphic(iid) && 2244 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2245 iid != vmIntrinsics::_invokeGeneric, 2246 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid))); 2247 2248 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2249 int index = invoke_method_table()->hash_to_index(hash); 2250 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2251 methodHandle m; 2252 if (spe == NULL || spe->method() == NULL) { 2253 spe = NULL; 2254 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2255 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2256 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier, 2257 methodHandle(), CompileThreshold, "MH", CHECK_(empty)); 2258 2259 // Now grab the lock. We might have to throw away the new method, 2260 // if a racing thread has managed to install one at the same time. 2261 { 2262 MutexLocker ml(SystemDictionary_lock, THREAD); 2263 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2264 if (spe == NULL) 2265 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2266 if (spe->method() == NULL) 2267 spe->set_method(m()); 2268 } 2269 } 2270 2271 assert(spe != NULL && spe->method() != NULL, ""); 2272 return spe->method(); 2273} 2274 2275// Helper for unpacking the return value from linkMethod and linkCallSite. 2276static methodHandle unpack_method_and_appendix(Handle mname, 2277 KlassHandle accessing_klass, 2278 objArrayHandle appendix_box, 2279 Handle* appendix_result, 2280 TRAPS) { 2281 methodHandle empty; 2282 if (mname.not_null()) { 2283 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2284 if (vmtarget != NULL && vmtarget->is_method()) { 2285 Method* m = (Method*)vmtarget; 2286 oop appendix = appendix_box->obj_at(0); 2287 if (TraceMethodHandles) { 2288 #ifndef PRODUCT 2289 tty->print("Linked method="INTPTR_FORMAT": ", m); 2290 m->print(); 2291 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2292 tty->cr(); 2293 #endif //PRODUCT 2294 } 2295 (*appendix_result) = Handle(THREAD, appendix); 2296 // the target is stored in the cpCache and if a reference to this 2297 // MethodName is dropped we need a way to make sure the 2298 // class_loader containing this method is kept alive. 2299 // FIXME: the appendix might also preserve this dependency. 2300 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2301 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2302 return methodHandle(THREAD, m); 2303 } 2304 } 2305 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2306 return empty; 2307} 2308 2309methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name, 2310 Symbol* signature, 2311 KlassHandle accessing_klass, 2312 Handle *appendix_result, 2313 Handle *method_type_result, 2314 TRAPS) { 2315 methodHandle empty; 2316 assert(EnableInvokeDynamic, ""); 2317 assert(!THREAD->is_Compiler_thread(), ""); 2318 Handle method_type = 2319 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2320 if (false) { // FIXME: Decide if the Java upcall should resolve signatures. 2321 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2322 } 2323 2324 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass(); 2325 int ref_kind = JVM_REF_invokeVirtual; 2326 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2327 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2328 assert(appendix_box->obj_at(0) == NULL, ""); 2329 2330 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2331 JavaCallArguments args; 2332 args.push_oop(accessing_klass()->java_mirror()); 2333 args.push_int(ref_kind); 2334 args.push_oop(mh_klass()->java_mirror()); 2335 args.push_oop(name_str()); 2336 args.push_oop(method_type()); 2337 args.push_oop(appendix_box()); 2338 JavaValue result(T_OBJECT); 2339 JavaCalls::call_static(&result, 2340 SystemDictionary::MethodHandleNatives_klass(), 2341 vmSymbols::linkMethod_name(), 2342 vmSymbols::linkMethod_signature(), 2343 &args, CHECK_(empty)); 2344 Handle mname(THREAD, (oop) result.get_jobject()); 2345 (*method_type_result) = method_type; 2346 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2347} 2348 2349 2350// Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2351// signature, as interpreted relative to the given class loader. 2352// Because of class loader constraints, all method handle usage must be 2353// consistent with this loader. 2354Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2355 KlassHandle accessing_klass, 2356 TRAPS) { 2357 Handle empty; 2358 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2359 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2360 int index = invoke_method_table()->hash_to_index(hash); 2361 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2362 if (spe != NULL && spe->method_type() != NULL) { 2363 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2364 return Handle(THREAD, spe->method_type()); 2365 } else if (THREAD->is_Compiler_thread()) { 2366 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2367 return Handle(); // do not attempt from within compiler, unless it was cached 2368 } 2369 2370 Handle class_loader, protection_domain; 2371 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader 2372 int npts = ArgumentCount(signature).size(); 2373 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2374 int arg = 0; 2375 Handle rt; // the return type from the signature 2376 ResourceMark rm(THREAD); 2377 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2378 oop mirror = NULL; 2379 if (is_on_bcp) { 2380 // Note: class_loader & protection_domain are both null at this point. 2381 mirror = ss.as_java_mirror(class_loader, protection_domain, 2382 SignatureStream::ReturnNull, CHECK_(empty)); 2383 if (mirror == NULL) { 2384 // fall back from BCP to accessing_klass 2385 if (accessing_klass.not_null()) { 2386 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2387 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2388 } 2389 is_on_bcp = false; 2390 } 2391 } 2392 if (!is_on_bcp) { 2393 // Resolve, throwing a real error if it doesn't work. 2394 mirror = ss.as_java_mirror(class_loader, protection_domain, 2395 SignatureStream::NCDFError, CHECK_(empty)); 2396 } 2397 if (ss.at_return_type()) 2398 rt = Handle(THREAD, mirror); 2399 else 2400 pts->obj_at_put(arg++, mirror); 2401 2402 // Check accessibility. 2403 if (ss.is_object() && accessing_klass.not_null()) { 2404 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2405 mirror = NULL; // safety 2406 // Emulate ConstantPool::verify_constant_pool_resolve. 2407 if (sel_klass->oop_is_objArray()) 2408 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2409 if (sel_klass->oop_is_instance()) { 2410 KlassHandle sel_kh(THREAD, sel_klass); 2411 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2412 } 2413 } 2414 } 2415 assert(arg == npts, ""); 2416 2417 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType 2418 JavaCallArguments args(Handle(THREAD, rt())); 2419 args.push_oop(pts()); 2420 JavaValue result(T_OBJECT); 2421 JavaCalls::call_static(&result, 2422 SystemDictionary::MethodHandleNatives_klass(), 2423 vmSymbols::findMethodHandleType_name(), 2424 vmSymbols::findMethodHandleType_signature(), 2425 &args, CHECK_(empty)); 2426 Handle method_type(THREAD, (oop) result.get_jobject()); 2427 2428 if (is_on_bcp) { 2429 // We can cache this MethodType inside the JVM. 2430 MutexLocker ml(SystemDictionary_lock, THREAD); 2431 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2432 if (spe == NULL) 2433 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2434 if (spe->method_type() == NULL) { 2435 spe->set_method_type(method_type()); 2436 } 2437 } 2438 2439 // report back to the caller with the MethodType 2440 return method_type; 2441} 2442 2443// Ask Java code to find or construct a method handle constant. 2444Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2445 int ref_kind, //e.g., JVM_REF_invokeVirtual 2446 KlassHandle callee, 2447 Symbol* name_sym, 2448 Symbol* signature, 2449 TRAPS) { 2450 Handle empty; 2451 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2452 Handle type; 2453 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2454 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2455 } else { 2456 ResourceMark rm(THREAD); 2457 SignatureStream ss(signature, false); 2458 if (!ss.is_done()) { 2459 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2460 SignatureStream::NCDFError, CHECK_(empty)); 2461 type = Handle(THREAD, mirror); 2462 ss.next(); 2463 if (!ss.is_done()) type = Handle(); // error! 2464 } 2465 } 2466 if (type.is_null()) { 2467 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2468 } 2469 2470 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2471 JavaCallArguments args; 2472 args.push_oop(caller->java_mirror()); // the referring class 2473 args.push_int(ref_kind); 2474 args.push_oop(callee->java_mirror()); // the target class 2475 args.push_oop(name()); 2476 args.push_oop(type()); 2477 JavaValue result(T_OBJECT); 2478 JavaCalls::call_static(&result, 2479 SystemDictionary::MethodHandleNatives_klass(), 2480 vmSymbols::linkMethodHandleConstant_name(), 2481 vmSymbols::linkMethodHandleConstant_signature(), 2482 &args, CHECK_(empty)); 2483 return Handle(THREAD, (oop) result.get_jobject()); 2484} 2485 2486// Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2487// name and signature, as interpreted relative to the given class loader. 2488methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2489 Handle bootstrap_specifier, 2490 Symbol* name, 2491 Symbol* type, 2492 Handle *appendix_result, 2493 Handle *method_type_result, 2494 TRAPS) { 2495 methodHandle empty; 2496 Handle bsm, info; 2497 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2498 bsm = bootstrap_specifier; 2499 } else { 2500 assert(bootstrap_specifier->is_objArray(), ""); 2501 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2502 int len = args->length(); 2503 assert(len >= 1, ""); 2504 bsm = Handle(THREAD, args->obj_at(0)); 2505 if (len > 1) { 2506 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2507 for (int i = 1; i < len; i++) 2508 args1->obj_at_put(i-1, args->obj_at(i)); 2509 info = Handle(THREAD, args1); 2510 } 2511 } 2512 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2513 "caller must supply a valid BSM"); 2514 2515 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2516 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2517 2518 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2519 assert(appendix_box->obj_at(0) == NULL, ""); 2520 2521 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2522 JavaCallArguments args; 2523 args.push_oop(caller->java_mirror()); 2524 args.push_oop(bsm()); 2525 args.push_oop(method_name()); 2526 args.push_oop(method_type()); 2527 args.push_oop(info()); 2528 args.push_oop(appendix_box); 2529 JavaValue result(T_OBJECT); 2530 JavaCalls::call_static(&result, 2531 SystemDictionary::MethodHandleNatives_klass(), 2532 vmSymbols::linkCallSite_name(), 2533 vmSymbols::linkCallSite_signature(), 2534 &args, CHECK_(empty)); 2535 Handle mname(THREAD, (oop) result.get_jobject()); 2536 (*method_type_result) = method_type; 2537 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2538} 2539 2540// Since the identity hash code for symbols changes when the symbols are 2541// moved from the regular perm gen (hash in the mark word) to the shared 2542// spaces (hash is the address), the classes loaded into the dictionary 2543// may be in the wrong buckets. 2544 2545void SystemDictionary::reorder_dictionary() { 2546 dictionary()->reorder_dictionary(); 2547} 2548 2549 2550void SystemDictionary::copy_buckets(char** top, char* end) { 2551 dictionary()->copy_buckets(top, end); 2552} 2553 2554 2555void SystemDictionary::copy_table(char** top, char* end) { 2556 dictionary()->copy_table(top, end); 2557} 2558 2559 2560void SystemDictionary::reverse() { 2561 dictionary()->reverse(); 2562} 2563 2564int SystemDictionary::number_of_classes() { 2565 return dictionary()->number_of_entries(); 2566} 2567 2568 2569// ---------------------------------------------------------------------------- 2570#ifndef PRODUCT 2571 2572void SystemDictionary::print() { 2573 dictionary()->print(); 2574 2575 // Placeholders 2576 GCMutexLocker mu(SystemDictionary_lock); 2577 placeholders()->print(); 2578 2579 // loader constraints - print under SD_lock 2580 constraints()->print(); 2581} 2582 2583#endif 2584 2585void SystemDictionary::verify() { 2586 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2587 guarantee(constraints() != NULL, 2588 "Verify of loader constraints failed"); 2589 guarantee(dictionary()->number_of_entries() >= 0 && 2590 placeholders()->number_of_entries() >= 0, 2591 "Verify of system dictionary failed"); 2592 2593 // Verify dictionary 2594 dictionary()->verify(); 2595 2596 GCMutexLocker mu(SystemDictionary_lock); 2597 placeholders()->verify(); 2598 2599 // Verify constraint table 2600 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2601 constraints()->verify(dictionary(), placeholders()); 2602} 2603 2604 2605void SystemDictionary::verify_obj_klass_present(Symbol* class_name, 2606 ClassLoaderData* loader_data) { 2607 GCMutexLocker mu(SystemDictionary_lock); 2608 Symbol* name; 2609 2610 Klass* probe = find_class(class_name, loader_data); 2611 if (probe == NULL) { 2612 probe = SystemDictionary::find_shared_class(class_name); 2613 if (probe == NULL) { 2614 name = find_placeholder(class_name, loader_data); 2615 } 2616 } 2617 guarantee(probe != NULL || name != NULL, 2618 "Loaded klasses should be in SystemDictionary"); 2619} 2620 2621#ifndef PRODUCT 2622 2623// statistics code 2624class ClassStatistics: AllStatic { 2625 private: 2626 static int nclasses; // number of classes 2627 static int nmethods; // number of methods 2628 static int nmethoddata; // number of methodData 2629 static int class_size; // size of class objects in words 2630 static int method_size; // size of method objects in words 2631 static int debug_size; // size of debug info in methods 2632 static int methoddata_size; // size of methodData objects in words 2633 2634 static void do_class(Klass* k) { 2635 nclasses++; 2636 class_size += k->size(); 2637 if (k->oop_is_instance()) { 2638 InstanceKlass* ik = (InstanceKlass*)k; 2639 class_size += ik->methods()->size(); 2640 class_size += ik->constants()->size(); 2641 class_size += ik->local_interfaces()->size(); 2642 class_size += ik->transitive_interfaces()->size(); 2643 // We do not have to count implementors, since we only store one! 2644 // SSS: How should these be accounted now that they have moved? 2645 // class_size += ik->fields()->length(); 2646 } 2647 } 2648 2649 static void do_method(Method* m) { 2650 nmethods++; 2651 method_size += m->size(); 2652 // class loader uses same objArray for empty vectors, so don't count these 2653 if (m->has_stackmap_table()) { 2654 method_size += m->stackmap_data()->size(); 2655 } 2656 2657 MethodData* mdo = m->method_data(); 2658 if (mdo != NULL) { 2659 nmethoddata++; 2660 methoddata_size += mdo->size(); 2661 } 2662 } 2663 2664 public: 2665 static void print() { 2666 SystemDictionary::classes_do(do_class); 2667 SystemDictionary::methods_do(do_method); 2668 tty->print_cr("Class statistics:"); 2669 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); 2670 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, 2671 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); 2672 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); 2673 } 2674}; 2675 2676 2677int ClassStatistics::nclasses = 0; 2678int ClassStatistics::nmethods = 0; 2679int ClassStatistics::nmethoddata = 0; 2680int ClassStatistics::class_size = 0; 2681int ClassStatistics::method_size = 0; 2682int ClassStatistics::debug_size = 0; 2683int ClassStatistics::methoddata_size = 0; 2684 2685void SystemDictionary::print_class_statistics() { 2686 ResourceMark rm; 2687 ClassStatistics::print(); 2688} 2689 2690 2691class MethodStatistics: AllStatic { 2692 public: 2693 enum { 2694 max_parameter_size = 10 2695 }; 2696 private: 2697 2698 static int _number_of_methods; 2699 static int _number_of_final_methods; 2700 static int _number_of_static_methods; 2701 static int _number_of_native_methods; 2702 static int _number_of_synchronized_methods; 2703 static int _number_of_profiled_methods; 2704 static int _number_of_bytecodes; 2705 static int _parameter_size_profile[max_parameter_size]; 2706 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; 2707 2708 static void initialize() { 2709 _number_of_methods = 0; 2710 _number_of_final_methods = 0; 2711 _number_of_static_methods = 0; 2712 _number_of_native_methods = 0; 2713 _number_of_synchronized_methods = 0; 2714 _number_of_profiled_methods = 0; 2715 _number_of_bytecodes = 0; 2716 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; 2717 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; 2718 }; 2719 2720 static void do_method(Method* m) { 2721 _number_of_methods++; 2722 // collect flag info 2723 if (m->is_final() ) _number_of_final_methods++; 2724 if (m->is_static() ) _number_of_static_methods++; 2725 if (m->is_native() ) _number_of_native_methods++; 2726 if (m->is_synchronized()) _number_of_synchronized_methods++; 2727 if (m->method_data() != NULL) _number_of_profiled_methods++; 2728 // collect parameter size info (add one for receiver, if any) 2729 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; 2730 // collect bytecodes info 2731 { 2732 Thread *thread = Thread::current(); 2733 HandleMark hm(thread); 2734 BytecodeStream s(methodHandle(thread, m)); 2735 Bytecodes::Code c; 2736 while ((c = s.next()) >= 0) { 2737 _number_of_bytecodes++; 2738 _bytecodes_profile[c]++; 2739 } 2740 } 2741 } 2742 2743 public: 2744 static void print() { 2745 initialize(); 2746 SystemDictionary::methods_do(do_method); 2747 // generate output 2748 tty->cr(); 2749 tty->print_cr("Method statistics (static):"); 2750 // flag distribution 2751 tty->cr(); 2752 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); 2753 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); 2754 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); 2755 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); 2756 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); 2757 // parameter size profile 2758 tty->cr(); 2759 { int tot = 0; 2760 int avg = 0; 2761 for (int i = 0; i < max_parameter_size; i++) { 2762 int n = _parameter_size_profile[i]; 2763 tot += n; 2764 avg += n*i; 2765 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); 2766 } 2767 assert(tot == _number_of_methods, "should be the same"); 2768 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); 2769 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); 2770 } 2771 // bytecodes profile 2772 tty->cr(); 2773 { int tot = 0; 2774 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { 2775 if (Bytecodes::is_defined(i)) { 2776 Bytecodes::Code c = Bytecodes::cast(i); 2777 int n = _bytecodes_profile[c]; 2778 tot += n; 2779 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); 2780 } 2781 } 2782 assert(tot == _number_of_bytecodes, "should be the same"); 2783 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); 2784 } 2785 tty->cr(); 2786 } 2787}; 2788 2789int MethodStatistics::_number_of_methods; 2790int MethodStatistics::_number_of_final_methods; 2791int MethodStatistics::_number_of_static_methods; 2792int MethodStatistics::_number_of_native_methods; 2793int MethodStatistics::_number_of_synchronized_methods; 2794int MethodStatistics::_number_of_profiled_methods; 2795int MethodStatistics::_number_of_bytecodes; 2796int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; 2797int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; 2798 2799 2800void SystemDictionary::print_method_statistics() { 2801 MethodStatistics::print(); 2802} 2803 2804#endif // PRODUCT 2805