systemDictionary.cpp revision 6412:53a41e7cbe05
1/* 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoaderData.inline.hpp" 27#include "classfile/dictionary.hpp" 28#include "classfile/javaClasses.hpp" 29#include "classfile/loaderConstraints.hpp" 30#include "classfile/placeholders.hpp" 31#include "classfile/resolutionErrors.hpp" 32#include "classfile/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/orderAccess.inline.hpp" 56#include "runtime/signature.hpp" 57#include "services/classLoadingService.hpp" 58#include "services/threadService.hpp" 59#include "utilities/macros.hpp" 60#include "utilities/ticks.hpp" 61 62#if INCLUDE_TRACE 63 #include "trace/tracing.hpp" 64#endif 65 66Dictionary* SystemDictionary::_dictionary = NULL; 67PlaceholderTable* SystemDictionary::_placeholders = NULL; 68Dictionary* SystemDictionary::_shared_dictionary = NULL; 69LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; 70ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; 71SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; 72 73 74int SystemDictionary::_number_of_modifications = 0; 75int SystemDictionary::_sdgeneration = 0; 76const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103, 77 20201,40423,99991}; 78 79oop SystemDictionary::_system_loader_lock_obj = NULL; 80 81Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] 82 = { NULL /*, NULL...*/ }; 83 84Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; 85 86oop SystemDictionary::_java_system_loader = NULL; 87 88bool SystemDictionary::_has_loadClassInternal = false; 89bool SystemDictionary::_has_checkPackageAccess = false; 90 91// lazily initialized klass variables 92Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; 93 94 95// ---------------------------------------------------------------------------- 96// Java-level SystemLoader 97 98oop SystemDictionary::java_system_loader() { 99 return _java_system_loader; 100} 101 102void SystemDictionary::compute_java_system_loader(TRAPS) { 103 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); 104 JavaValue result(T_OBJECT); 105 JavaCalls::call_static(&result, 106 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), 107 vmSymbols::getSystemClassLoader_name(), 108 vmSymbols::void_classloader_signature(), 109 CHECK); 110 111 _java_system_loader = (oop)result.get_jobject(); 112} 113 114 115ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) { 116 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); 117 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL); 118} 119 120// ---------------------------------------------------------------------------- 121// debugging 122 123#ifdef ASSERT 124 125// return true if class_name contains no '.' (internal format is '/') 126bool SystemDictionary::is_internal_format(Symbol* class_name) { 127 if (class_name != NULL) { 128 ResourceMark rm; 129 char* name = class_name->as_C_string(); 130 return strchr(name, '.') == NULL; 131 } else { 132 return true; 133 } 134} 135 136#endif 137 138// ---------------------------------------------------------------------------- 139// Parallel class loading check 140 141bool SystemDictionary::is_parallelCapable(Handle class_loader) { 142 if (UnsyncloadClass || class_loader.is_null()) return true; 143 if (AlwaysLockClassLoader) return false; 144 return java_lang_ClassLoader::parallelCapable(class_loader()); 145} 146// ---------------------------------------------------------------------------- 147// ParallelDefineClass flag does not apply to bootclass loader 148bool SystemDictionary::is_parallelDefine(Handle class_loader) { 149 if (class_loader.is_null()) return false; 150 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { 151 return true; 152 } 153 return false; 154} 155 156/** 157 * Returns true if the passed class loader is the extension class loader. 158 */ 159bool SystemDictionary::is_ext_class_loader(Handle class_loader) { 160 if (class_loader.is_null()) { 161 return false; 162 } 163 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader()); 164} 165 166// ---------------------------------------------------------------------------- 167// Resolving of classes 168 169// Forwards to resolve_or_null 170 171Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { 172 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); 173 if (HAS_PENDING_EXCEPTION || klass == NULL) { 174 KlassHandle k_h(THREAD, klass); 175 // can return a null klass 176 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD); 177 } 178 return klass; 179} 180 181Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, 182 bool throw_error, 183 KlassHandle klass_h, TRAPS) { 184 if (HAS_PENDING_EXCEPTION) { 185 // If we have a pending exception we forward it to the caller, unless throw_error is true, 186 // in which case we have to check whether the pending exception is a ClassNotFoundException, 187 // and if so convert it to a NoClassDefFoundError 188 // And chain the original ClassNotFoundException 189 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { 190 ResourceMark rm(THREAD); 191 assert(klass_h() == NULL, "Should not have result with exception pending"); 192 Handle e(THREAD, PENDING_EXCEPTION); 193 CLEAR_PENDING_EXCEPTION; 194 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); 195 } else { 196 return NULL; 197 } 198 } 199 // Class not found, throw appropriate error or exception depending on value of throw_error 200 if (klass_h() == NULL) { 201 ResourceMark rm(THREAD); 202 if (throw_error) { 203 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); 204 } else { 205 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); 206 } 207 } 208 return (Klass*)klass_h(); 209} 210 211 212Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, 213 bool throw_error, TRAPS) 214{ 215 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); 216} 217 218 219// Forwards to resolve_instance_class_or_null 220 221Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { 222 assert(!THREAD->is_Compiler_thread(), 223 err_msg("can not load classes with compiler thread: class=%s, classloader=%s", 224 class_name->as_C_string(), 225 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string())); 226 if (FieldType::is_array(class_name)) { 227 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 228 } else if (FieldType::is_obj(class_name)) { 229 ResourceMark rm(THREAD); 230 // Ignore wrapping L and ;. 231 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, 232 class_name->utf8_length() - 2, CHECK_NULL); 233 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL); 234 } else { 235 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); 236 } 237} 238 239Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { 240 return resolve_or_null(class_name, Handle(), Handle(), THREAD); 241} 242 243// Forwards to resolve_instance_class_or_null 244 245Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, 246 Handle class_loader, 247 Handle protection_domain, 248 TRAPS) { 249 assert(FieldType::is_array(class_name), "must be array"); 250 Klass* k = NULL; 251 FieldArrayInfo fd; 252 // dimension and object_key in FieldArrayInfo are assigned as a side-effect 253 // of this call 254 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); 255 if (t == T_OBJECT) { 256 // naked oop "k" is OK here -- we assign back into it 257 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), 258 class_loader, 259 protection_domain, 260 CHECK_NULL); 261 if (k != NULL) { 262 k = k->array_klass(fd.dimension(), CHECK_NULL); 263 } 264 } else { 265 k = Universe::typeArrayKlassObj(t); 266 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); 267 } 268 return k; 269} 270 271 272// Must be called for any super-class or super-interface resolution 273// during class definition to allow class circularity checking 274// super-interface callers: 275// parse_interfaces - for defineClass & jvmtiRedefineClasses 276// super-class callers: 277// ClassFileParser - for defineClass & jvmtiRedefineClasses 278// load_shared_class - while loading a class from shared archive 279// resolve_instance_class_or_null: 280// via: handle_parallel_super_load 281// when resolving a class that has an existing placeholder with 282// a saved superclass [i.e. a defineClass is currently in progress] 283// if another thread is trying to resolve the class, it must do 284// super-class checks on its own thread to catch class circularity 285// This last call is critical in class circularity checking for cases 286// where classloading is delegated to different threads and the 287// classloader lock is released. 288// Take the case: Base->Super->Base 289// 1. If thread T1 tries to do a defineClass of class Base 290// resolve_super_or_fail creates placeholder: T1, Base (super Super) 291// 2. resolve_instance_class_or_null does not find SD or placeholder for Super 292// so it tries to load Super 293// 3. If we load the class internally, or user classloader uses same thread 294// loadClassFromxxx or defineClass via parseClassFile Super ... 295// 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) 296// 3.3 resolve_instance_class_or_null Base, finds placeholder for Base 297// 3.4 calls resolve_super_or_fail Base 298// 3.5 finds T1,Base -> throws class circularity 299//OR 4. If T2 tries to resolve Super via defineClass Super ... 300// 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) 301// 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) 302// 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 303// 4.4 finds T2, Super -> throws class circularity 304// Must be called, even if superclass is null, since this is 305// where the placeholder entry is created which claims this 306// thread is loading this class/classloader. 307Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, 308 Symbol* class_name, 309 Handle class_loader, 310 Handle protection_domain, 311 bool is_superclass, 312 TRAPS) { 313 // Double-check, if child class is already loaded, just return super-class,interface 314 // Don't add a placedholder if already loaded, i.e. already in system dictionary 315 // Make sure there's a placeholder for the *child* before resolving. 316 // Used as a claim that this thread is currently loading superclass/classloader 317 // Used here for ClassCircularity checks and also for heap verification 318 // (every InstanceKlass in the heap needs to be in the system dictionary 319 // or have a placeholder). 320 // Must check ClassCircularity before checking if super class is already loaded 321 // 322 // We might not already have a placeholder if this child_name was 323 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); 324 // the name of the class might not be known until the stream is actually 325 // parsed. 326 // Bugs 4643874, 4715493 327 // compute_hash can have a safepoint 328 329 ClassLoaderData* loader_data = class_loader_data(class_loader); 330 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data); 331 int d_index = dictionary()->hash_to_index(d_hash); 332 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data); 333 int p_index = placeholders()->hash_to_index(p_hash); 334 // can't throw error holding a lock 335 bool child_already_loaded = false; 336 bool throw_circularity_error = false; 337 { 338 MutexLocker mu(SystemDictionary_lock, THREAD); 339 Klass* childk = find_class(d_index, d_hash, child_name, loader_data); 340 Klass* quicksuperk; 341 // to support // loading: if child done loading, just return superclass 342 // if class_name, & class_loader don't match: 343 // if initial define, SD update will give LinkageError 344 // if redefine: compare_class_versions will give HIERARCHY_CHANGED 345 // so we don't throw an exception here. 346 // see: nsk redefclass014 & java.lang.instrument Instrument032 347 if ((childk != NULL ) && (is_superclass) && 348 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) && 349 350 ((quicksuperk->name() == class_name) && 351 (quicksuperk->class_loader() == class_loader()))) { 352 return quicksuperk; 353 } else { 354 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); 355 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { 356 throw_circularity_error = true; 357 } 358 } 359 if (!throw_circularity_error) { 360 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); 361 } 362 } 363 if (throw_circularity_error) { 364 ResourceMark rm(THREAD); 365 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); 366 } 367 368// java.lang.Object should have been found above 369 assert(class_name != NULL, "null super class for resolving"); 370 // Resolve the super class or interface, check results on return 371 Klass* superk = SystemDictionary::resolve_or_null(class_name, 372 class_loader, 373 protection_domain, 374 THREAD); 375 376 KlassHandle superk_h(THREAD, superk); 377 378 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up 379 // It is no longer necessary to keep the placeholder table alive until update_dictionary 380 // or error. GC used to walk the placeholder table as strong roots. 381 // The instanceKlass is kept alive because the class loader is on the stack, 382 // which keeps the loader_data alive, as well as all instanceKlasses in 383 // the loader_data. parseClassFile adds the instanceKlass to loader_data. 384 { 385 MutexLocker mu(SystemDictionary_lock, THREAD); 386 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); 387 SystemDictionary_lock->notify_all(); 388 } 389 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { 390 // can null superk 391 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD)); 392 } 393 394 return superk_h(); 395} 396 397void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, 398 Handle class_loader, 399 Handle protection_domain, 400 TRAPS) { 401 if(!has_checkPackageAccess()) return; 402 403 // Now we have to call back to java to check if the initating class has access 404 JavaValue result(T_VOID); 405 if (TraceProtectionDomainVerification) { 406 // Print out trace information 407 tty->print_cr("Checking package access"); 408 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); 409 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); 410 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); 411 } 412 413 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); 414 JavaCalls::call_special(&result, 415 class_loader, 416 system_loader, 417 vmSymbols::checkPackageAccess_name(), 418 vmSymbols::class_protectiondomain_signature(), 419 Handle(THREAD, klass->java_mirror()), 420 protection_domain, 421 THREAD); 422 423 if (TraceProtectionDomainVerification) { 424 if (HAS_PENDING_EXCEPTION) { 425 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); 426 } else { 427 tty->print_cr(" -> granted"); 428 } 429 tty->cr(); 430 } 431 432 if (HAS_PENDING_EXCEPTION) return; 433 434 // If no exception has been thrown, we have validated the protection domain 435 // Insert the protection domain of the initiating class into the set. 436 { 437 // We recalculate the entry here -- we've called out to java since 438 // the last time it was calculated. 439 ClassLoaderData* loader_data = class_loader_data(class_loader); 440 441 Symbol* kn = klass->name(); 442 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data); 443 int d_index = dictionary()->hash_to_index(d_hash); 444 445 MutexLocker mu(SystemDictionary_lock, THREAD); 446 { 447 // Note that we have an entry, and entries can be deleted only during GC, 448 // so we cannot allow GC to occur while we're holding this entry. 449 450 // We're using a No_Safepoint_Verifier to catch any place where we 451 // might potentially do a GC at all. 452 // Dictionary::do_unloading() asserts that classes in SD are only 453 // unloaded at a safepoint. Anonymous classes are not in SD. 454 No_Safepoint_Verifier nosafepoint; 455 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data, 456 protection_domain, THREAD); 457 } 458 } 459} 460 461// We only get here if this thread finds that another thread 462// has already claimed the placeholder token for the current operation, 463// but that other thread either never owned or gave up the 464// object lock 465// Waits on SystemDictionary_lock to indicate placeholder table updated 466// On return, caller must recheck placeholder table state 467// 468// We only get here if 469// 1) custom classLoader, i.e. not bootstrap classloader 470// 2) UnsyncloadClass not set 471// 3) custom classLoader has broken the class loader objectLock 472// so another thread got here in parallel 473// 474// lockObject must be held. 475// Complicated dance due to lock ordering: 476// Must first release the classloader object lock to 477// allow initial definer to complete the class definition 478// and to avoid deadlock 479// Reclaim classloader lock object with same original recursion count 480// Must release SystemDictionary_lock after notify, since 481// class loader lock must be claimed before SystemDictionary_lock 482// to prevent deadlocks 483// 484// The notify allows applications that did an untimed wait() on 485// the classloader object lock to not hang. 486void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { 487 assert_lock_strong(SystemDictionary_lock); 488 489 bool calledholdinglock 490 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); 491 assert(calledholdinglock,"must hold lock for notify"); 492 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); 493 ObjectSynchronizer::notifyall(lockObject, THREAD); 494 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); 495 SystemDictionary_lock->wait(); 496 SystemDictionary_lock->unlock(); 497 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); 498 SystemDictionary_lock->lock(); 499} 500 501// If the class in is in the placeholder table, class loading is in progress 502// For cases where the application changes threads to load classes, it 503// is critical to ClassCircularity detection that we try loading 504// the superclass on the same thread internally, so we do parallel 505// super class loading here. 506// This also is critical in cases where the original thread gets stalled 507// even in non-circularity situations. 508// Note: must call resolve_super_or_fail even if null super - 509// to force placeholder entry creation for this class for circularity detection 510// Caller must check for pending exception 511// Returns non-null Klass* if other thread has completed load 512// and we are done, 513// If return null Klass* and no pending exception, the caller must load the class 514instanceKlassHandle SystemDictionary::handle_parallel_super_load( 515 Symbol* name, Symbol* superclassname, Handle class_loader, 516 Handle protection_domain, Handle lockObject, TRAPS) { 517 518 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 519 ClassLoaderData* loader_data = class_loader_data(class_loader); 520 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 521 int d_index = dictionary()->hash_to_index(d_hash); 522 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 523 int p_index = placeholders()->hash_to_index(p_hash); 524 525 // superk is not used, resolve_super called for circularity check only 526 // This code is reached in two situations. One if this thread 527 // is loading the same class twice (e.g. ClassCircularity, or 528 // java.lang.instrument). 529 // The second is if another thread started the resolve_super first 530 // and has not yet finished. 531 // In both cases the original caller will clean up the placeholder 532 // entry on error. 533 Klass* superk = SystemDictionary::resolve_super_or_fail(name, 534 superclassname, 535 class_loader, 536 protection_domain, 537 true, 538 CHECK_(nh)); 539 540 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete 541 // Serial class loaders and bootstrap classloader do wait for superclass loads 542 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { 543 MutexLocker mu(SystemDictionary_lock, THREAD); 544 // Check if classloading completed while we were loading superclass or waiting 545 Klass* check = find_class(d_index, d_hash, name, loader_data); 546 if (check != NULL) { 547 // Klass is already loaded, so just return it 548 return(instanceKlassHandle(THREAD, check)); 549 } else { 550 return nh; 551 } 552 } 553 554 // must loop to both handle other placeholder updates 555 // and spurious notifications 556 bool super_load_in_progress = true; 557 PlaceholderEntry* placeholder; 558 while (super_load_in_progress) { 559 MutexLocker mu(SystemDictionary_lock, THREAD); 560 // Check if classloading completed while we were loading superclass or waiting 561 Klass* check = find_class(d_index, d_hash, name, loader_data); 562 if (check != NULL) { 563 // Klass is already loaded, so just return it 564 return(instanceKlassHandle(THREAD, check)); 565 } else { 566 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 567 if (placeholder && placeholder->super_load_in_progress() ){ 568 // Before UnsyncloadClass: 569 // We only get here if the application has released the 570 // classloader lock when another thread was in the middle of loading a 571 // superclass/superinterface for this class, and now 572 // this thread is also trying to load this class. 573 // To minimize surprises, the first thread that started to 574 // load a class should be the one to complete the loading 575 // with the classfile it initially expected. 576 // This logic has the current thread wait once it has done 577 // all the superclass/superinterface loading it can, until 578 // the original thread completes the class loading or fails 579 // If it completes we will use the resulting InstanceKlass 580 // which we will find below in the systemDictionary. 581 // We also get here for parallel bootstrap classloader 582 if (class_loader.is_null()) { 583 SystemDictionary_lock->wait(); 584 } else { 585 double_lock_wait(lockObject, THREAD); 586 } 587 } else { 588 // If not in SD and not in PH, other thread's load must have failed 589 super_load_in_progress = false; 590 } 591 } 592 } 593 return (nh); 594} 595 596 597Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, 598 Handle class_loader, 599 Handle protection_domain, 600 TRAPS) { 601 assert(name != NULL && !FieldType::is_array(name) && 602 !FieldType::is_obj(name), "invalid class name"); 603 604 Ticks class_load_start_time = Ticks::now(); 605 606 // UseNewReflection 607 // Fix for 4474172; see evaluation for more details 608 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 609 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL); 610 611 // Do lookup to see if class already exist and the protection domain 612 // has the right access 613 // This call uses find which checks protection domain already matches 614 // All subsequent calls use find_class, and set has_loaded_class so that 615 // before we return a result we call out to java to check for valid protection domain 616 // to allow returning the Klass* and add it to the pd_set if it is valid 617 unsigned int d_hash = dictionary()->compute_hash(name, loader_data); 618 int d_index = dictionary()->hash_to_index(d_hash); 619 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data, 620 protection_domain, THREAD); 621 if (probe != NULL) return probe; 622 623 624 // Non-bootstrap class loaders will call out to class loader and 625 // define via jvm/jni_DefineClass which will acquire the 626 // class loader object lock to protect against multiple threads 627 // defining the class in parallel by accident. 628 // This lock must be acquired here so the waiter will find 629 // any successful result in the SystemDictionary and not attempt 630 // the define 631 // ParallelCapable Classloaders and the bootstrap classloader, 632 // or all classloaders with UnsyncloadClass do not acquire lock here 633 bool DoObjectLock = true; 634 if (is_parallelCapable(class_loader)) { 635 DoObjectLock = false; 636 } 637 638 unsigned int p_hash = placeholders()->compute_hash(name, loader_data); 639 int p_index = placeholders()->hash_to_index(p_hash); 640 641 // Class is not in SystemDictionary so we have to do loading. 642 // Make sure we are synchronized on the class loader before we proceed 643 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 644 check_loader_lock_contention(lockObject, THREAD); 645 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 646 647 // Check again (after locking) if class already exist in SystemDictionary 648 bool class_has_been_loaded = false; 649 bool super_load_in_progress = false; 650 bool havesupername = false; 651 instanceKlassHandle k; 652 PlaceholderEntry* placeholder; 653 Symbol* superclassname = NULL; 654 655 { 656 MutexLocker mu(SystemDictionary_lock, THREAD); 657 Klass* check = find_class(d_index, d_hash, name, loader_data); 658 if (check != NULL) { 659 // Klass is already loaded, so just return it 660 class_has_been_loaded = true; 661 k = instanceKlassHandle(THREAD, check); 662 } else { 663 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); 664 if (placeholder && placeholder->super_load_in_progress()) { 665 super_load_in_progress = true; 666 if (placeholder->havesupername() == true) { 667 superclassname = placeholder->supername(); 668 havesupername = true; 669 } 670 } 671 } 672 } 673 674 // If the class is in the placeholder table, class loading is in progress 675 if (super_load_in_progress && havesupername==true) { 676 k = SystemDictionary::handle_parallel_super_load(name, superclassname, 677 class_loader, protection_domain, lockObject, THREAD); 678 if (HAS_PENDING_EXCEPTION) { 679 return NULL; 680 } 681 if (!k.is_null()) { 682 class_has_been_loaded = true; 683 } 684 } 685 686 bool throw_circularity_error = false; 687 if (!class_has_been_loaded) { 688 bool load_instance_added = false; 689 690 // add placeholder entry to record loading instance class 691 // Five cases: 692 // All cases need to prevent modifying bootclasssearchpath 693 // in parallel with a classload of same classname 694 // Redefineclasses uses existence of the placeholder for the duration 695 // of the class load to prevent concurrent redefinition of not completely 696 // defined classes. 697 // case 1. traditional classloaders that rely on the classloader object lock 698 // - no other need for LOAD_INSTANCE 699 // case 2. traditional classloaders that break the classloader object lock 700 // as a deadlock workaround. Detection of this case requires that 701 // this check is done while holding the classloader object lock, 702 // and that lock is still held when calling classloader's loadClass. 703 // For these classloaders, we ensure that the first requestor 704 // completes the load and other requestors wait for completion. 705 // case 3. UnsyncloadClass - don't use objectLocker 706 // With this flag, we allow parallel classloading of a 707 // class/classloader pair 708 // case4. Bootstrap classloader - don't own objectLocker 709 // This classloader supports parallelism at the classloader level, 710 // but only allows a single load of a class/classloader pair. 711 // No performance benefit and no deadlock issues. 712 // case 5. parallelCapable user level classloaders - without objectLocker 713 // Allow parallel classloading of a class/classloader pair 714 715 { 716 MutexLocker mu(SystemDictionary_lock, THREAD); 717 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { 718 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 719 if (oldprobe) { 720 // only need check_seen_thread once, not on each loop 721 // 6341374 java/lang/Instrument with -Xcomp 722 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { 723 throw_circularity_error = true; 724 } else { 725 // case 1: traditional: should never see load_in_progress. 726 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { 727 728 // case 4: bootstrap classloader: prevent futile classloading, 729 // wait on first requestor 730 if (class_loader.is_null()) { 731 SystemDictionary_lock->wait(); 732 } else { 733 // case 2: traditional with broken classloader lock. wait on first 734 // requestor. 735 double_lock_wait(lockObject, THREAD); 736 } 737 // Check if classloading completed while we were waiting 738 Klass* check = find_class(d_index, d_hash, name, loader_data); 739 if (check != NULL) { 740 // Klass is already loaded, so just return it 741 k = instanceKlassHandle(THREAD, check); 742 class_has_been_loaded = true; 743 } 744 // check if other thread failed to load and cleaned up 745 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); 746 } 747 } 748 } 749 } 750 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock 751 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try 752 // LOAD_INSTANCE in parallel 753 754 if (!throw_circularity_error && !class_has_been_loaded) { 755 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); 756 load_instance_added = true; 757 // For class loaders that do not acquire the classloader object lock, 758 // if they did not catch another thread holding LOAD_INSTANCE, 759 // need a check analogous to the acquire ObjectLocker/find_class 760 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL 761 // one final check if the load has already completed 762 // class loaders holding the ObjectLock shouldn't find the class here 763 Klass* check = find_class(d_index, d_hash, name, loader_data); 764 if (check != NULL) { 765 // Klass is already loaded, so return it after checking/adding protection domain 766 k = instanceKlassHandle(THREAD, check); 767 class_has_been_loaded = true; 768 } 769 } 770 } 771 772 // must throw error outside of owning lock 773 if (throw_circularity_error) { 774 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); 775 ResourceMark rm(THREAD); 776 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); 777 } 778 779 if (!class_has_been_loaded) { 780 781 // Do actual loading 782 k = load_instance_class(name, class_loader, THREAD); 783 784 // For UnsyncloadClass only 785 // If they got a linkageError, check if a parallel class load succeeded. 786 // If it did, then for bytecode resolution the specification requires 787 // that we return the same result we did for the other thread, i.e. the 788 // successfully loaded InstanceKlass 789 // Should not get here for classloaders that support parallelism 790 // with the new cleaner mechanism, even with AllowParallelDefineClass 791 // Bootstrap goes through here to allow for an extra guarantee check 792 if (UnsyncloadClass || (class_loader.is_null())) { 793 if (k.is_null() && HAS_PENDING_EXCEPTION 794 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { 795 MutexLocker mu(SystemDictionary_lock, THREAD); 796 Klass* check = find_class(d_index, d_hash, name, loader_data); 797 if (check != NULL) { 798 // Klass is already loaded, so just use it 799 k = instanceKlassHandle(THREAD, check); 800 CLEAR_PENDING_EXCEPTION; 801 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); 802 } 803 } 804 } 805 806 // If everything was OK (no exceptions, no null return value), and 807 // class_loader is NOT the defining loader, do a little more bookkeeping. 808 if (!HAS_PENDING_EXCEPTION && !k.is_null() && 809 k->class_loader() != class_loader()) { 810 811 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); 812 813 // Need to check for a PENDING_EXCEPTION again; check_constraints 814 // can throw and doesn't use the CHECK macro. 815 if (!HAS_PENDING_EXCEPTION) { 816 { // Grabbing the Compile_lock prevents systemDictionary updates 817 // during compilations. 818 MutexLocker mu(Compile_lock, THREAD); 819 update_dictionary(d_index, d_hash, p_index, p_hash, 820 k, class_loader, THREAD); 821 } 822 823 if (JvmtiExport::should_post_class_load()) { 824 Thread *thread = THREAD; 825 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); 826 JvmtiExport::post_class_load((JavaThread *) thread, k()); 827 } 828 } 829 } 830 } // load_instance_class loop 831 832 if (load_instance_added == true) { 833 // clean up placeholder entries for LOAD_INSTANCE success or error 834 // This brackets the SystemDictionary updates for both defining 835 // and initiating loaders 836 MutexLocker mu(SystemDictionary_lock, THREAD); 837 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); 838 SystemDictionary_lock->notify_all(); 839 } 840 } 841 842 if (HAS_PENDING_EXCEPTION || k.is_null()) { 843 return NULL; 844 } 845 846 post_class_load_event(class_load_start_time, k, class_loader); 847 848#ifdef ASSERT 849 { 850 ClassLoaderData* loader_data = k->class_loader_data(); 851 MutexLocker mu(SystemDictionary_lock, THREAD); 852 Klass* kk = find_class(name, loader_data); 853 assert(kk == k(), "should be present in dictionary"); 854 } 855#endif 856 857 // return if the protection domain in NULL 858 if (protection_domain() == NULL) return k(); 859 860 // Check the protection domain has the right access 861 { 862 MutexLocker mu(SystemDictionary_lock, THREAD); 863 // Note that we have an entry, and entries can be deleted only during GC, 864 // so we cannot allow GC to occur while we're holding this entry. 865 // We're using a No_Safepoint_Verifier to catch any place where we 866 // might potentially do a GC at all. 867 // Dictionary::do_unloading() asserts that classes in SD are only 868 // unloaded at a safepoint. Anonymous classes are not in SD. 869 No_Safepoint_Verifier nosafepoint; 870 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, 871 loader_data, 872 protection_domain)) { 873 return k(); 874 } 875 } 876 877 // Verify protection domain. If it fails an exception is thrown 878 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); 879 880 return k(); 881} 882 883 884// This routine does not lock the system dictionary. 885// 886// Since readers don't hold a lock, we must make sure that system 887// dictionary entries are only removed at a safepoint (when only one 888// thread is running), and are added to in a safe way (all links must 889// be updated in an MT-safe manner). 890// 891// Callers should be aware that an entry could be added just after 892// _dictionary->bucket(index) is read here, so the caller will not see 893// the new entry. 894 895Klass* SystemDictionary::find(Symbol* class_name, 896 Handle class_loader, 897 Handle protection_domain, 898 TRAPS) { 899 900 // UseNewReflection 901 // The result of this call should be consistent with the result 902 // of the call to resolve_instance_class_or_null(). 903 // See evaluation 6790209 and 4474172 for more details. 904 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); 905 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); 906 907 if (loader_data == NULL) { 908 // If the ClassLoaderData has not been setup, 909 // then the class loader has no entries in the dictionary. 910 return NULL; 911 } 912 913 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 914 int d_index = dictionary()->hash_to_index(d_hash); 915 916 { 917 // Note that we have an entry, and entries can be deleted only during GC, 918 // so we cannot allow GC to occur while we're holding this entry. 919 // We're using a No_Safepoint_Verifier to catch any place where we 920 // might potentially do a GC at all. 921 // Dictionary::do_unloading() asserts that classes in SD are only 922 // unloaded at a safepoint. Anonymous classes are not in SD. 923 No_Safepoint_Verifier nosafepoint; 924 return dictionary()->find(d_index, d_hash, class_name, loader_data, 925 protection_domain, THREAD); 926 } 927} 928 929 930// Look for a loaded instance or array klass by name. Do not do any loading. 931// return NULL in case of error. 932Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, 933 Handle class_loader, 934 Handle protection_domain, 935 TRAPS) { 936 Klass* k = NULL; 937 assert(class_name != NULL, "class name must be non NULL"); 938 939 if (FieldType::is_array(class_name)) { 940 // The name refers to an array. Parse the name. 941 // dimension and object_key in FieldArrayInfo are assigned as a 942 // side-effect of this call 943 FieldArrayInfo fd; 944 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 945 if (t != T_OBJECT) { 946 k = Universe::typeArrayKlassObj(t); 947 } else { 948 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); 949 } 950 if (k != NULL) { 951 k = k->array_klass_or_null(fd.dimension()); 952 } 953 } else { 954 k = find(class_name, class_loader, protection_domain, THREAD); 955 } 956 return k; 957} 958 959// Note: this method is much like resolve_from_stream, but 960// updates no supplemental data structures. 961// TODO consolidate the two methods with a helper routine? 962Klass* SystemDictionary::parse_stream(Symbol* class_name, 963 Handle class_loader, 964 Handle protection_domain, 965 ClassFileStream* st, 966 KlassHandle host_klass, 967 GrowableArray<Handle>* cp_patches, 968 TRAPS) { 969 TempNewSymbol parsed_name = NULL; 970 971 Ticks class_load_start_time = Ticks::now(); 972 973 ClassLoaderData* loader_data; 974 if (host_klass.not_null()) { 975 // Create a new CLD for anonymous class, that uses the same class loader 976 // as the host_klass 977 guarantee(host_klass->class_loader() == class_loader(), "should be the same"); 978 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL); 979 loader_data->record_dependency(host_klass(), CHECK_NULL); 980 } else { 981 loader_data = ClassLoaderData::class_loader_data(class_loader()); 982 } 983 984 // Parse the stream. Note that we do this even though this klass might 985 // already be present in the SystemDictionary, otherwise we would not 986 // throw potential ClassFormatErrors. 987 // 988 // Note: "name" is updated. 989 990 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 991 loader_data, 992 protection_domain, 993 host_klass, 994 cp_patches, 995 parsed_name, 996 true, 997 THREAD); 998 999 1000 if (host_klass.not_null() && k.not_null()) { 1001 k->set_host_klass(host_klass()); 1002 // If it's anonymous, initialize it now, since nobody else will. 1003 1004 { 1005 MutexLocker mu_r(Compile_lock, THREAD); 1006 1007 // Add to class hierarchy, initialize vtables, and do possible 1008 // deoptimizations. 1009 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block 1010 1011 // But, do not add to system dictionary. 1012 1013 // compiled code dependencies need to be validated anyway 1014 notice_modification(); 1015 } 1016 1017 // Rewrite and patch constant pool here. 1018 k->link_class(CHECK_NULL); 1019 if (cp_patches != NULL) { 1020 k->constants()->patch_resolved_references(cp_patches); 1021 } 1022 k->eager_initialize(CHECK_NULL); 1023 1024 // notify jvmti 1025 if (JvmtiExport::should_post_class_load()) { 1026 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1027 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1028 } 1029 1030 post_class_load_event(class_load_start_time, k, class_loader); 1031 } 1032 assert(host_klass.not_null() || cp_patches == NULL, 1033 "cp_patches only found with host_klass"); 1034 1035 return k(); 1036} 1037 1038// Add a klass to the system from a stream (called by jni_DefineClass and 1039// JVM_DefineClass). 1040// Note: class_name can be NULL. In that case we do not know the name of 1041// the class until we have parsed the stream. 1042 1043Klass* SystemDictionary::resolve_from_stream(Symbol* class_name, 1044 Handle class_loader, 1045 Handle protection_domain, 1046 ClassFileStream* st, 1047 bool verify, 1048 TRAPS) { 1049 1050 // Classloaders that support parallelism, e.g. bootstrap classloader, 1051 // or all classloaders with UnsyncloadClass do not acquire lock here 1052 bool DoObjectLock = true; 1053 if (is_parallelCapable(class_loader)) { 1054 DoObjectLock = false; 1055 } 1056 1057 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL); 1058 1059 // Make sure we are synchronized on the class loader before we proceed 1060 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1061 check_loader_lock_contention(lockObject, THREAD); 1062 ObjectLocker ol(lockObject, THREAD, DoObjectLock); 1063 1064 TempNewSymbol parsed_name = NULL; 1065 1066 // Parse the stream. Note that we do this even though this klass might 1067 // already be present in the SystemDictionary, otherwise we would not 1068 // throw potential ClassFormatErrors. 1069 // 1070 // Note: "name" is updated. 1071 1072 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, 1073 loader_data, 1074 protection_domain, 1075 parsed_name, 1076 verify, 1077 THREAD); 1078 1079 const char* pkg = "java/"; 1080 if (!HAS_PENDING_EXCEPTION && 1081 !class_loader.is_null() && 1082 parsed_name != NULL && 1083 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { 1084 // It is illegal to define classes in the "java." package from 1085 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader 1086 ResourceMark rm(THREAD); 1087 char* name = parsed_name->as_C_string(); 1088 char* index = strrchr(name, '/'); 1089 *index = '\0'; // chop to just the package name 1090 while ((index = strchr(name, '/')) != NULL) { 1091 *index = '.'; // replace '/' with '.' in package name 1092 } 1093 const char* fmt = "Prohibited package name: %s"; 1094 size_t len = strlen(fmt) + strlen(name); 1095 char* message = NEW_RESOURCE_ARRAY(char, len); 1096 jio_snprintf(message, len, fmt, name); 1097 Exceptions::_throw_msg(THREAD_AND_LOCATION, 1098 vmSymbols::java_lang_SecurityException(), message); 1099 } 1100 1101 if (!HAS_PENDING_EXCEPTION) { 1102 assert(parsed_name != NULL, "Sanity"); 1103 assert(class_name == NULL || class_name == parsed_name, "name mismatch"); 1104 // Verification prevents us from creating names with dots in them, this 1105 // asserts that that's the case. 1106 assert(is_internal_format(parsed_name), 1107 "external class name format used internally"); 1108 1109 // Add class just loaded 1110 // If a class loader supports parallel classloading handle parallel define requests 1111 // find_or_define_instance_class may return a different InstanceKlass 1112 if (is_parallelCapable(class_loader)) { 1113 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); 1114 } else { 1115 define_instance_class(k, THREAD); 1116 } 1117 } 1118 1119 // Make sure we have an entry in the SystemDictionary on success 1120 debug_only( { 1121 if (!HAS_PENDING_EXCEPTION) { 1122 assert(parsed_name != NULL, "parsed_name is still null?"); 1123 Symbol* h_name = k->name(); 1124 ClassLoaderData *defining_loader_data = k->class_loader_data(); 1125 1126 MutexLocker mu(SystemDictionary_lock, THREAD); 1127 1128 Klass* check = find_class(parsed_name, loader_data); 1129 assert(check == k(), "should be present in the dictionary"); 1130 1131 Klass* check2 = find_class(h_name, defining_loader_data); 1132 assert(check == check2, "name inconsistancy in SystemDictionary"); 1133 } 1134 } ); 1135 1136 return k(); 1137} 1138 1139 1140void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 1141 int number_of_entries) { 1142 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>), 1143 "bad shared dictionary size."); 1144 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); 1145} 1146 1147 1148// If there is a shared dictionary, then find the entry for the 1149// given shared system class, if any. 1150 1151Klass* SystemDictionary::find_shared_class(Symbol* class_name) { 1152 if (shared_dictionary() != NULL) { 1153 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL); 1154 int d_index = shared_dictionary()->hash_to_index(d_hash); 1155 1156 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); 1157 } else { 1158 return NULL; 1159 } 1160} 1161 1162 1163// Load a class from the shared spaces (found through the shared system 1164// dictionary). Force the superclass and all interfaces to be loaded. 1165// Update the class definition to include sibling classes and no 1166// subclasses (yet). [Classes in the shared space are not part of the 1167// object hierarchy until loaded.] 1168 1169instanceKlassHandle SystemDictionary::load_shared_class( 1170 Symbol* class_name, Handle class_loader, TRAPS) { 1171 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); 1172 return load_shared_class(ik, class_loader, THREAD); 1173} 1174 1175instanceKlassHandle SystemDictionary::load_shared_class( 1176 instanceKlassHandle ik, Handle class_loader, TRAPS) { 1177 assert(class_loader.is_null(), "non-null classloader for shared class?"); 1178 if (ik.not_null()) { 1179 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1180 Symbol* class_name = ik->name(); 1181 1182 // Found the class, now load the superclass and interfaces. If they 1183 // are shared, add them to the main system dictionary and reset 1184 // their hierarchy references (supers, subs, and interfaces). 1185 1186 if (ik->super() != NULL) { 1187 Symbol* cn = ik->super()->name(); 1188 resolve_super_or_fail(class_name, cn, 1189 class_loader, Handle(), true, CHECK_(nh)); 1190 } 1191 1192 Array<Klass*>* interfaces = ik->local_interfaces(); 1193 int num_interfaces = interfaces->length(); 1194 for (int index = 0; index < num_interfaces; index++) { 1195 Klass* k = interfaces->at(index); 1196 1197 // Note: can not use InstanceKlass::cast here because 1198 // interfaces' InstanceKlass's C++ vtbls haven't been 1199 // reinitialized yet (they will be once the interface classes 1200 // are loaded) 1201 Symbol* name = k->name(); 1202 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); 1203 } 1204 1205 // Adjust methods to recover missing data. They need addresses for 1206 // interpreter entry points and their default native method address 1207 // must be reset. 1208 1209 // Updating methods must be done under a lock so multiple 1210 // threads don't update these in parallel 1211 // Shared classes are all currently loaded by the bootstrap 1212 // classloader, so this will never cause a deadlock on 1213 // a custom class loader lock. 1214 1215 { 1216 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); 1217 check_loader_lock_contention(lockObject, THREAD); 1218 ObjectLocker ol(lockObject, THREAD, true); 1219 ik->restore_unshareable_info(CHECK_(nh)); 1220 } 1221 1222 if (TraceClassLoading) { 1223 ResourceMark rm; 1224 tty->print("[Loaded %s", ik->external_name()); 1225 tty->print(" from shared objects file"); 1226 tty->print_cr("]"); 1227 } 1228 // notify a class loaded from shared object 1229 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()), 1230 true /* shared class */); 1231 } 1232 return ik; 1233} 1234 1235 1236instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { 1237 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1238 if (class_loader.is_null()) { 1239 1240 // Search the shared system dictionary for classes preloaded into the 1241 // shared spaces. 1242 instanceKlassHandle k; 1243 { 1244 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); 1245 k = load_shared_class(class_name, class_loader, THREAD); 1246 } 1247 1248 if (k.is_null()) { 1249 // Use VM class loader 1250 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); 1251 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); 1252 } 1253 1254 // find_or_define_instance_class may return a different InstanceKlass 1255 if (!k.is_null()) { 1256 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); 1257 } 1258 return k; 1259 } else { 1260 // Use user specified class loader to load class. Call loadClass operation on class_loader. 1261 ResourceMark rm(THREAD); 1262 1263 assert(THREAD->is_Java_thread(), "must be a JavaThread"); 1264 JavaThread* jt = (JavaThread*) THREAD; 1265 1266 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), 1267 ClassLoader::perf_app_classload_selftime(), 1268 ClassLoader::perf_app_classload_count(), 1269 jt->get_thread_stat()->perf_recursion_counts_addr(), 1270 jt->get_thread_stat()->perf_timers_addr(), 1271 PerfClassTraceTime::CLASS_LOAD); 1272 1273 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); 1274 // Translate to external class name format, i.e., convert '/' chars to '.' 1275 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); 1276 1277 JavaValue result(T_OBJECT); 1278 1279 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass()); 1280 1281 // Call public unsynchronized loadClass(String) directly for all class loaders 1282 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will 1283 // acquire a class-name based lock rather than the class loader object lock. 1284 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), 1285 // so the call to loadClassInternal() was not required. 1286 // 1287 // UnsyncloadClass flag means both call loadClass(String) and do 1288 // not acquire the class loader lock even for class loaders that are 1289 // not parallelCapable. This was a risky transitional 1290 // flag for diagnostic purposes only. It is risky to call 1291 // custom class loaders without synchronization. 1292 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of 1293 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. 1294 // Do NOT assume this will be supported in future releases. 1295 // 1296 // Added MustCallLoadClassInternal in case we discover in the field 1297 // a customer that counts on this call 1298 if (MustCallLoadClassInternal && has_loadClassInternal()) { 1299 JavaCalls::call_special(&result, 1300 class_loader, 1301 spec_klass, 1302 vmSymbols::loadClassInternal_name(), 1303 vmSymbols::string_class_signature(), 1304 string, 1305 CHECK_(nh)); 1306 } else { 1307 JavaCalls::call_virtual(&result, 1308 class_loader, 1309 spec_klass, 1310 vmSymbols::loadClass_name(), 1311 vmSymbols::string_class_signature(), 1312 string, 1313 CHECK_(nh)); 1314 } 1315 1316 assert(result.get_type() == T_OBJECT, "just checking"); 1317 oop obj = (oop) result.get_jobject(); 1318 1319 // Primitive classes return null since forName() can not be 1320 // used to obtain any of the Class objects representing primitives or void 1321 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { 1322 instanceKlassHandle k = 1323 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj)); 1324 // For user defined Java class loaders, check that the name returned is 1325 // the same as that requested. This check is done for the bootstrap 1326 // loader when parsing the class file. 1327 if (class_name == k->name()) { 1328 return k; 1329 } 1330 } 1331 // Class is not found or has the wrong name, return NULL 1332 return nh; 1333 } 1334} 1335 1336void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { 1337 1338 ClassLoaderData* loader_data = k->class_loader_data(); 1339 Handle class_loader_h(THREAD, loader_data->class_loader()); 1340 1341 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){} 1342 1343 // for bootstrap and other parallel classloaders don't acquire lock, 1344 // use placeholder token 1345 // If a parallelCapable class loader calls define_instance_class instead of 1346 // find_or_define_instance_class to get here, we have a timing 1347 // hole with systemDictionary updates and check_constraints 1348 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { 1349 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, 1350 compute_loader_lock_object(class_loader_h, THREAD)), 1351 "define called without lock"); 1352 } 1353 1354 // Check class-loading constraints. Throw exception if violation is detected. 1355 // Grabs and releases SystemDictionary_lock 1356 // The check_constraints/find_class call and update_dictionary sequence 1357 // must be "atomic" for a specific class/classloader pair so we never 1358 // define two different instanceKlasses for that class/classloader pair. 1359 // Existing classloaders will call define_instance_class with the 1360 // classloader lock held 1361 // Parallel classloaders will call find_or_define_instance_class 1362 // which will require a token to perform the define class 1363 Symbol* name_h = k->name(); 1364 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1365 int d_index = dictionary()->hash_to_index(d_hash); 1366 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); 1367 1368 // Register class just loaded with class loader (placed in Vector) 1369 // Note we do this before updating the dictionary, as this can 1370 // fail with an OutOfMemoryError (if it does, we will *not* put this 1371 // class in the dictionary and will not update the class hierarchy). 1372 // JVMTI FollowReferences needs to find the classes this way. 1373 if (k->class_loader() != NULL) { 1374 methodHandle m(THREAD, Universe::loader_addClass_method()); 1375 JavaValue result(T_VOID); 1376 JavaCallArguments args(class_loader_h); 1377 args.push_oop(Handle(THREAD, k->java_mirror())); 1378 JavaCalls::call(&result, m, &args, CHECK); 1379 } 1380 1381 // Add the new class. We need recompile lock during update of CHA. 1382 { 1383 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1384 int p_index = placeholders()->hash_to_index(p_hash); 1385 1386 MutexLocker mu_r(Compile_lock, THREAD); 1387 1388 // Add to class hierarchy, initialize vtables, and do possible 1389 // deoptimizations. 1390 add_to_hierarchy(k, CHECK); // No exception, but can block 1391 1392 // Add to systemDictionary - so other classes can see it. 1393 // Grabs and releases SystemDictionary_lock 1394 update_dictionary(d_index, d_hash, p_index, p_hash, 1395 k, class_loader_h, THREAD); 1396 } 1397 k->eager_initialize(THREAD); 1398 1399 // notify jvmti 1400 if (JvmtiExport::should_post_class_load()) { 1401 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); 1402 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); 1403 1404 } 1405 1406} 1407 1408// Support parallel classloading 1409// All parallel class loaders, including bootstrap classloader 1410// lock a placeholder entry for this class/class_loader pair 1411// to allow parallel defines of different classes for this class loader 1412// With AllowParallelDefine flag==true, in case they do not synchronize around 1413// FindLoadedClass/DefineClass, calls, we check for parallel 1414// loading for them, wait if a defineClass is in progress 1415// and return the initial requestor's results 1416// This flag does not apply to the bootstrap classloader. 1417// With AllowParallelDefine flag==false, call through to define_instance_class 1418// which will throw LinkageError: duplicate class definition. 1419// False is the requested default. 1420// For better performance, the class loaders should synchronize 1421// findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they 1422// potentially waste time reading and parsing the bytestream. 1423// Note: VM callers should ensure consistency of k/class_name,class_loader 1424instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { 1425 1426 instanceKlassHandle nh = instanceKlassHandle(); // null Handle 1427 Symbol* name_h = k->name(); // passed in class_name may be null 1428 ClassLoaderData* loader_data = class_loader_data(class_loader); 1429 1430 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data); 1431 int d_index = dictionary()->hash_to_index(d_hash); 1432 1433// Hold SD lock around find_class and placeholder creation for DEFINE_CLASS 1434 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data); 1435 int p_index = placeholders()->hash_to_index(p_hash); 1436 PlaceholderEntry* probe; 1437 1438 { 1439 MutexLocker mu(SystemDictionary_lock, THREAD); 1440 // First check if class already defined 1441 if (UnsyncloadClass || (is_parallelDefine(class_loader))) { 1442 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1443 if (check != NULL) { 1444 return(instanceKlassHandle(THREAD, check)); 1445 } 1446 } 1447 1448 // Acquire define token for this class/classloader 1449 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); 1450 // Wait if another thread defining in parallel 1451 // All threads wait - even those that will throw duplicate class: otherwise 1452 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails 1453 // if other thread has not finished updating dictionary 1454 while (probe->definer() != NULL) { 1455 SystemDictionary_lock->wait(); 1456 } 1457 // Only special cases allow parallel defines and can use other thread's results 1458 // Other cases fall through, and may run into duplicate defines 1459 // caught by finding an entry in the SystemDictionary 1460 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) { 1461 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1462 SystemDictionary_lock->notify_all(); 1463#ifdef ASSERT 1464 Klass* check = find_class(d_index, d_hash, name_h, loader_data); 1465 assert(check != NULL, "definer missed recording success"); 1466#endif 1467 return(instanceKlassHandle(THREAD, probe->instance_klass())); 1468 } else { 1469 // This thread will define the class (even if earlier thread tried and had an error) 1470 probe->set_definer(THREAD); 1471 } 1472 } 1473 1474 define_instance_class(k, THREAD); 1475 1476 Handle linkage_exception = Handle(); // null handle 1477 1478 // definer must notify any waiting threads 1479 { 1480 MutexLocker mu(SystemDictionary_lock, THREAD); 1481 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); 1482 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); 1483 if (probe != NULL) { 1484 if (HAS_PENDING_EXCEPTION) { 1485 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); 1486 CLEAR_PENDING_EXCEPTION; 1487 } else { 1488 probe->set_instance_klass(k()); 1489 } 1490 probe->set_definer(NULL); 1491 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); 1492 SystemDictionary_lock->notify_all(); 1493 } 1494 } 1495 1496 // Can't throw exception while holding lock due to rank ordering 1497 if (linkage_exception() != NULL) { 1498 THROW_OOP_(linkage_exception(), nh); // throws exception and returns 1499 } 1500 1501 return k; 1502} 1503Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { 1504 // If class_loader is NULL we synchronize on _system_loader_lock_obj 1505 if (class_loader.is_null()) { 1506 return Handle(THREAD, _system_loader_lock_obj); 1507 } else { 1508 return class_loader; 1509 } 1510} 1511 1512// This method is added to check how often we have to wait to grab loader 1513// lock. The results are being recorded in the performance counters defined in 1514// ClassLoader::_sync_systemLoaderLockContentionRate and 1515// ClassLoader::_sync_nonSystemLoaderLockConteionRate. 1516void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { 1517 if (!UsePerfData) { 1518 return; 1519 } 1520 1521 assert(!loader_lock.is_null(), "NULL lock object"); 1522 1523 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) 1524 == ObjectSynchronizer::owner_other) { 1525 // contention will likely happen, so increment the corresponding 1526 // contention counter. 1527 if (loader_lock() == _system_loader_lock_obj) { 1528 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); 1529 } else { 1530 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); 1531 } 1532 } 1533} 1534 1535// ---------------------------------------------------------------------------- 1536// Lookup 1537 1538Klass* SystemDictionary::find_class(int index, unsigned int hash, 1539 Symbol* class_name, 1540 ClassLoaderData* loader_data) { 1541 assert_locked_or_safepoint(SystemDictionary_lock); 1542 assert (index == dictionary()->index_for(class_name, loader_data), 1543 "incorrect index?"); 1544 1545 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data); 1546 return k; 1547} 1548 1549 1550// Basic find on classes in the midst of being loaded 1551Symbol* SystemDictionary::find_placeholder(Symbol* class_name, 1552 ClassLoaderData* loader_data) { 1553 assert_locked_or_safepoint(SystemDictionary_lock); 1554 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data); 1555 int p_index = placeholders()->hash_to_index(p_hash); 1556 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); 1557} 1558 1559 1560// Used for assertions and verification only 1561Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { 1562 #ifndef ASSERT 1563 guarantee(VerifyBeforeGC || 1564 VerifyDuringGC || 1565 VerifyBeforeExit || 1566 VerifyDuringStartup || 1567 VerifyAfterGC, "too expensive"); 1568 #endif 1569 assert_locked_or_safepoint(SystemDictionary_lock); 1570 1571 // First look in the loaded class array 1572 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data); 1573 int d_index = dictionary()->hash_to_index(d_hash); 1574 return find_class(d_index, d_hash, class_name, loader_data); 1575} 1576 1577 1578// Get the next class in the diictionary. 1579Klass* SystemDictionary::try_get_next_class() { 1580 return dictionary()->try_get_next_class(); 1581} 1582 1583 1584// ---------------------------------------------------------------------------- 1585// Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock 1586// is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in 1587// before a new class is used. 1588 1589void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { 1590 assert(k.not_null(), "just checking"); 1591 assert_locked_or_safepoint(Compile_lock); 1592 1593 // Link into hierachy. Make sure the vtables are initialized before linking into 1594 k->append_to_sibling_list(); // add to superklass/sibling list 1595 k->process_interfaces(THREAD); // handle all "implements" declarations 1596 k->set_init_state(InstanceKlass::loaded); 1597 // Now flush all code that depended on old class hierarchy. 1598 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) 1599 // Also, first reinitialize vtable because it may have gotten out of synch 1600 // while the new class wasn't connected to the class hierarchy. 1601 Universe::flush_dependents_on(k); 1602} 1603 1604 1605// ---------------------------------------------------------------------------- 1606// GC support 1607 1608// Following roots during mark-sweep is separated in two phases. 1609// 1610// The first phase follows preloaded classes and all other system 1611// classes, since these will never get unloaded anyway. 1612// 1613// The second phase removes (unloads) unreachable classes from the 1614// system dictionary and follows the remaining classes' contents. 1615 1616void SystemDictionary::always_strong_oops_do(OopClosure* blk) { 1617 blk->do_oop(&_java_system_loader); 1618 blk->do_oop(&_system_loader_lock_obj); 1619 1620 dictionary()->always_strong_oops_do(blk); 1621 1622 // Visit extra methods 1623 invoke_method_table()->oops_do(blk); 1624} 1625 1626void SystemDictionary::always_strong_classes_do(KlassClosure* closure) { 1627 // Follow all system classes and temporary placeholders in dictionary 1628 dictionary()->always_strong_classes_do(closure); 1629 1630 // Placeholders. These represent classes we're actively loading. 1631 placeholders()->classes_do(closure); 1632} 1633 1634// Calculate a "good" systemdictionary size based 1635// on predicted or current loaded classes count 1636int SystemDictionary::calculate_systemdictionary_size(int classcount) { 1637 int newsize = _old_default_sdsize; 1638 if ((classcount > 0) && !DumpSharedSpaces) { 1639 int desiredsize = classcount/_average_depth_goal; 1640 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1; 1641 newsize = _primelist[++_sdgeneration]) { 1642 if (desiredsize <= newsize) { 1643 break; 1644 } 1645 } 1646 } 1647 return newsize; 1648} 1649 1650#ifdef ASSERT 1651class VerifySDReachableAndLiveClosure : public OopClosure { 1652private: 1653 BoolObjectClosure* _is_alive; 1654 1655 template <class T> void do_oop_work(T* p) { 1656 oop obj = oopDesc::load_decode_heap_oop(p); 1657 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); 1658 } 1659 1660public: 1661 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } 1662 1663 virtual void do_oop(oop* p) { do_oop_work(p); } 1664 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1665}; 1666#endif 1667 1668// Assumes classes in the SystemDictionary are only unloaded at a safepoint 1669// Note: anonymous classes are not in the SD. 1670bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { 1671 // First, mark for unload all ClassLoaderData referencing a dead class loader. 1672 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive); 1673 bool unloading_occurred = false; 1674 if (has_dead_loaders) { 1675 unloading_occurred = dictionary()->do_unloading(); 1676 constraints()->purge_loader_constraints(); 1677 resolution_errors()->purge_resolution_errors(); 1678 } 1679 // Oops referenced by the system dictionary may get unreachable independently 1680 // of the class loader (eg. cached protection domain oops). So we need to 1681 // explicitly unlink them here instead of in Dictionary::do_unloading. 1682 dictionary()->unlink(is_alive); 1683#ifdef ASSERT 1684 VerifySDReachableAndLiveClosure cl(is_alive); 1685 dictionary()->oops_do(&cl); 1686#endif 1687 return unloading_occurred; 1688} 1689 1690void SystemDictionary::oops_do(OopClosure* f) { 1691 f->do_oop(&_java_system_loader); 1692 f->do_oop(&_system_loader_lock_obj); 1693 1694 // Adjust dictionary 1695 dictionary()->oops_do(f); 1696 1697 // Visit extra methods 1698 invoke_method_table()->oops_do(f); 1699} 1700 1701// Extended Class redefinition support. 1702// If one of these classes is replaced, we need to replace it in these places. 1703// KlassClosure::do_klass should take the address of a class but we can 1704// change that later. 1705void SystemDictionary::preloaded_classes_do(KlassClosure* f) { 1706 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { 1707 f->do_klass(_well_known_klasses[k]); 1708 } 1709 1710 { 1711 for (int i = 0; i < T_VOID+1; i++) { 1712 if (_box_klasses[i] != NULL) { 1713 assert(i >= T_BOOLEAN, "checking"); 1714 f->do_klass(_box_klasses[i]); 1715 } 1716 } 1717 } 1718 1719 FilteredFieldsMap::classes_do(f); 1720} 1721 1722void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) { 1723 f->do_klass(_abstract_ownable_synchronizer_klass); 1724} 1725 1726// Just the classes from defining class loaders 1727// Don't iterate over placeholders 1728void SystemDictionary::classes_do(void f(Klass*)) { 1729 dictionary()->classes_do(f); 1730} 1731 1732// Added for initialize_itable_for_klass 1733// Just the classes from defining class loaders 1734// Don't iterate over placeholders 1735void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) { 1736 dictionary()->classes_do(f, CHECK); 1737} 1738 1739// All classes, and their class loaders 1740// Don't iterate over placeholders 1741void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) { 1742 dictionary()->classes_do(f); 1743} 1744 1745void SystemDictionary::placeholders_do(void f(Symbol*)) { 1746 placeholders()->entries_do(f); 1747} 1748 1749void SystemDictionary::methods_do(void f(Method*)) { 1750 dictionary()->methods_do(f); 1751 invoke_method_table()->methods_do(f); 1752} 1753 1754// ---------------------------------------------------------------------------- 1755// Lazily load klasses 1756 1757void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { 1758 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); 1759 1760 // if multiple threads calling this function, only one thread will load 1761 // the class. The other threads will find the loaded version once the 1762 // class is loaded. 1763 Klass* aos = _abstract_ownable_synchronizer_klass; 1764 if (aos == NULL) { 1765 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); 1766 // Force a fence to prevent any read before the write completes 1767 OrderAccess::fence(); 1768 _abstract_ownable_synchronizer_klass = k; 1769 } 1770} 1771 1772// ---------------------------------------------------------------------------- 1773// Initialization 1774 1775void SystemDictionary::initialize(TRAPS) { 1776 // Allocate arrays 1777 assert(dictionary() == NULL, 1778 "SystemDictionary should only be initialized once"); 1779 _sdgeneration = 0; 1780 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount)); 1781 _placeholders = new PlaceholderTable(_nof_buckets); 1782 _number_of_modifications = 0; 1783 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); 1784 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); 1785 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); 1786 1787 // Allocate private object used as system class loader lock 1788 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); 1789 // Initialize basic classes 1790 initialize_preloaded_classes(CHECK); 1791} 1792 1793// Compact table of directions on the initialization of klasses: 1794static const short wk_init_info[] = { 1795 #define WK_KLASS_INIT_INFO(name, symbol, option) \ 1796 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ 1797 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ 1798 | (int)SystemDictionary::option ), 1799 WK_KLASSES_DO(WK_KLASS_INIT_INFO) 1800 #undef WK_KLASS_INIT_INFO 1801 0 1802}; 1803 1804bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { 1805 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1806 int info = wk_init_info[id - FIRST_WKID]; 1807 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1808 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); 1809 Klass** klassp = &_well_known_klasses[id]; 1810 bool must_load = (init_opt < SystemDictionary::Opt); 1811 if ((*klassp) == NULL) { 1812 if (must_load) { 1813 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class 1814 } else { 1815 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass 1816 } 1817 } 1818 return ((*klassp) != NULL); 1819} 1820 1821void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { 1822 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); 1823 for (int id = (int)start_id; id < (int)limit_id; id++) { 1824 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 1825 int info = wk_init_info[id - FIRST_WKID]; 1826 int sid = (info >> CEIL_LG_OPTION_LIMIT); 1827 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); 1828 1829 initialize_wk_klass((WKID)id, opt, CHECK); 1830 } 1831 1832 // move the starting value forward to the limit: 1833 start_id = limit_id; 1834} 1835 1836void SystemDictionary::initialize_preloaded_classes(TRAPS) { 1837 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); 1838 // Preload commonly used klasses 1839 WKID scan = FIRST_WKID; 1840 // first do Object, then String, Class 1841 if (UseSharedSpaces) { 1842 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); 1843 // Initialize the constant pool for the Object_class 1844 InstanceKlass* ik = InstanceKlass::cast(Object_klass()); 1845 ik->constants()->restore_unshareable_info(CHECK); 1846 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1847 } else { 1848 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); 1849 } 1850 1851 // Calculate offsets for String and Class classes since they are loaded and 1852 // can be used after this point. 1853 java_lang_String::compute_offsets(); 1854 java_lang_Class::compute_offsets(); 1855 1856 // Fixup mirrors for classes loaded before java.lang.Class. 1857 // These calls iterate over the objects currently in the perm gen 1858 // so calling them at this point is matters (not before when there 1859 // are fewer objects and not later after there are more objects 1860 // in the perm gen. 1861 Universe::initialize_basic_type_mirrors(CHECK); 1862 Universe::fixup_mirrors(CHECK); 1863 1864 // do a bunch more: 1865 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); 1866 1867 // Preload ref klasses and set reference types 1868 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); 1869 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); 1870 1871 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); 1872 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); 1873 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); 1874 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); 1875 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); 1876 1877 // JSR 292 classes 1878 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); 1879 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); 1880 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); 1881 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); 1882 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); 1883 1884 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); 1885 _box_klasses[T_CHAR] = WK_KLASS(Character_klass); 1886 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); 1887 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); 1888 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); 1889 _box_klasses[T_SHORT] = WK_KLASS(Short_klass); 1890 _box_klasses[T_INT] = WK_KLASS(Integer_klass); 1891 _box_klasses[T_LONG] = WK_KLASS(Long_klass); 1892 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); 1893 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); 1894 1895 { // Compute whether we should use loadClass or loadClassInternal when loading classes. 1896 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); 1897 _has_loadClassInternal = (method != NULL); 1898 } 1899 { // Compute whether we should use checkPackageAccess or NOT 1900 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); 1901 _has_checkPackageAccess = (method != NULL); 1902 } 1903} 1904 1905// Tells if a given klass is a box (wrapper class, such as java.lang.Integer). 1906// If so, returns the basic type it holds. If not, returns T_OBJECT. 1907BasicType SystemDictionary::box_klass_type(Klass* k) { 1908 assert(k != NULL, ""); 1909 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { 1910 if (_box_klasses[i] == k) 1911 return (BasicType)i; 1912 } 1913 return T_OBJECT; 1914} 1915 1916// Constraints on class loaders. The details of the algorithm can be 1917// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java 1918// Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is 1919// that the system dictionary needs to maintain a set of contraints that 1920// must be satisfied by all classes in the dictionary. 1921// if defining is true, then LinkageError if already in systemDictionary 1922// if initiating loader, then ok if InstanceKlass matches existing entry 1923 1924void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, 1925 instanceKlassHandle k, 1926 Handle class_loader, bool defining, 1927 TRAPS) { 1928 const char *linkage_error = NULL; 1929 { 1930 Symbol* name = k->name(); 1931 ClassLoaderData *loader_data = class_loader_data(class_loader); 1932 1933 MutexLocker mu(SystemDictionary_lock, THREAD); 1934 1935 Klass* check = find_class(d_index, d_hash, name, loader_data); 1936 if (check != (Klass*)NULL) { 1937 // if different InstanceKlass - duplicate class definition, 1938 // else - ok, class loaded by a different thread in parallel, 1939 // we should only have found it if it was done loading and ok to use 1940 // system dictionary only holds instance classes, placeholders 1941 // also holds array classes 1942 1943 assert(check->oop_is_instance(), "noninstance in systemdictionary"); 1944 if ((defining == true) || (k() != check)) { 1945 linkage_error = "loader (instance of %s): attempted duplicate class " 1946 "definition for name: \"%s\""; 1947 } else { 1948 return; 1949 } 1950 } 1951 1952#ifdef ASSERT 1953 Symbol* ph_check = find_placeholder(name, loader_data); 1954 assert(ph_check == NULL || ph_check == name, "invalid symbol"); 1955#endif 1956 1957 if (linkage_error == NULL) { 1958 if (constraints()->check_or_update(k, class_loader, name) == false) { 1959 linkage_error = "loader constraint violation: loader (instance of %s)" 1960 " previously initiated loading for a different type with name \"%s\""; 1961 } 1962 } 1963 } 1964 1965 // Throw error now if needed (cannot throw while holding 1966 // SystemDictionary_lock because of rank ordering) 1967 1968 if (linkage_error) { 1969 ResourceMark rm(THREAD); 1970 const char* class_loader_name = loader_name(class_loader()); 1971 char* type_name = k->name()->as_C_string(); 1972 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + 1973 strlen(type_name); 1974 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 1975 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); 1976 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 1977 } 1978} 1979 1980 1981// Update system dictionary - done after check_constraint and add_to_hierachy 1982// have been called. 1983void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, 1984 int p_index, unsigned int p_hash, 1985 instanceKlassHandle k, 1986 Handle class_loader, 1987 TRAPS) { 1988 // Compile_lock prevents systemDictionary updates during compilations 1989 assert_locked_or_safepoint(Compile_lock); 1990 Symbol* name = k->name(); 1991 ClassLoaderData *loader_data = class_loader_data(class_loader); 1992 1993 { 1994 MutexLocker mu1(SystemDictionary_lock, THREAD); 1995 1996 // See whether biased locking is enabled and if so set it for this 1997 // klass. 1998 // Note that this must be done past the last potential blocking 1999 // point / safepoint. We enable biased locking lazily using a 2000 // VM_Operation to iterate the SystemDictionary and installing the 2001 // biasable mark word into each InstanceKlass's prototype header. 2002 // To avoid race conditions where we accidentally miss enabling the 2003 // optimization for one class in the process of being added to the 2004 // dictionary, we must not safepoint after the test of 2005 // BiasedLocking::enabled(). 2006 if (UseBiasedLocking && BiasedLocking::enabled()) { 2007 // Set biased locking bit for all loaded classes; it will be 2008 // cleared if revocation occurs too often for this type 2009 // NOTE that we must only do this when the class is initally 2010 // defined, not each time it is referenced from a new class loader 2011 if (k->class_loader() == class_loader()) { 2012 k->set_prototype_header(markOopDesc::biased_locking_prototype()); 2013 } 2014 } 2015 2016 // Make a new system dictionary entry. 2017 Klass* sd_check = find_class(d_index, d_hash, name, loader_data); 2018 if (sd_check == NULL) { 2019 dictionary()->add_klass(name, loader_data, k); 2020 notice_modification(); 2021 } 2022#ifdef ASSERT 2023 sd_check = find_class(d_index, d_hash, name, loader_data); 2024 assert (sd_check != NULL, "should have entry in system dictionary"); 2025 // Note: there may be a placeholder entry: for circularity testing 2026 // or for parallel defines 2027#endif 2028 SystemDictionary_lock->notify_all(); 2029 } 2030} 2031 2032 2033// Try to find a class name using the loader constraints. The 2034// loader constraints might know about a class that isn't fully loaded 2035// yet and these will be ignored. 2036Klass* SystemDictionary::find_constrained_instance_or_array_klass( 2037 Symbol* class_name, Handle class_loader, TRAPS) { 2038 2039 // First see if it has been loaded directly. 2040 // Force the protection domain to be null. (This removes protection checks.) 2041 Handle no_protection_domain; 2042 Klass* klass = find_instance_or_array_klass(class_name, class_loader, 2043 no_protection_domain, CHECK_NULL); 2044 if (klass != NULL) 2045 return klass; 2046 2047 // Now look to see if it has been loaded elsewhere, and is subject to 2048 // a loader constraint that would require this loader to return the 2049 // klass that is already loaded. 2050 if (FieldType::is_array(class_name)) { 2051 // For array classes, their Klass*s are not kept in the 2052 // constraint table. The element Klass*s are. 2053 FieldArrayInfo fd; 2054 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); 2055 if (t != T_OBJECT) { 2056 klass = Universe::typeArrayKlassObj(t); 2057 } else { 2058 MutexLocker mu(SystemDictionary_lock, THREAD); 2059 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); 2060 } 2061 // If element class already loaded, allocate array klass 2062 if (klass != NULL) { 2063 klass = klass->array_klass_or_null(fd.dimension()); 2064 } 2065 } else { 2066 MutexLocker mu(SystemDictionary_lock, THREAD); 2067 // Non-array classes are easy: simply check the constraint table. 2068 klass = constraints()->find_constrained_klass(class_name, class_loader); 2069 } 2070 2071 return klass; 2072} 2073 2074 2075bool SystemDictionary::add_loader_constraint(Symbol* class_name, 2076 Handle class_loader1, 2077 Handle class_loader2, 2078 Thread* THREAD) { 2079 ClassLoaderData* loader_data1 = class_loader_data(class_loader1); 2080 ClassLoaderData* loader_data2 = class_loader_data(class_loader2); 2081 2082 Symbol* constraint_name = NULL; 2083 if (!FieldType::is_array(class_name)) { 2084 constraint_name = class_name; 2085 } else { 2086 // For array classes, their Klass*s are not kept in the 2087 // constraint table. The element classes are. 2088 FieldArrayInfo fd; 2089 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); 2090 // primitive types always pass 2091 if (t != T_OBJECT) { 2092 return true; 2093 } else { 2094 constraint_name = fd.object_key(); 2095 } 2096 } 2097 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1); 2098 int d_index1 = dictionary()->hash_to_index(d_hash1); 2099 2100 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2); 2101 int d_index2 = dictionary()->hash_to_index(d_hash2); 2102 { 2103 MutexLocker mu_s(SystemDictionary_lock, THREAD); 2104 2105 // Better never do a GC while we're holding these oops 2106 No_Safepoint_Verifier nosafepoint; 2107 2108 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1); 2109 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2); 2110 return constraints()->add_entry(constraint_name, klass1, class_loader1, 2111 klass2, class_loader2); 2112 } 2113} 2114 2115// Add entry to resolution error table to record the error when the first 2116// attempt to resolve a reference to a class has failed. 2117void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, 2118 Symbol* error, Symbol* message) { 2119 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2120 int index = resolution_errors()->hash_to_index(hash); 2121 { 2122 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2123 resolution_errors()->add_entry(index, hash, pool, which, error, message); 2124 } 2125} 2126 2127// Delete a resolution error for RedefineClasses for a constant pool is going away 2128void SystemDictionary::delete_resolution_error(ConstantPool* pool) { 2129 resolution_errors()->delete_entry(pool); 2130} 2131 2132// Lookup resolution error table. Returns error if found, otherwise NULL. 2133Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which, 2134 Symbol** message) { 2135 unsigned int hash = resolution_errors()->compute_hash(pool, which); 2136 int index = resolution_errors()->hash_to_index(hash); 2137 { 2138 MutexLocker ml(SystemDictionary_lock, Thread::current()); 2139 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); 2140 if (entry != NULL) { 2141 *message = entry->message(); 2142 return entry->error(); 2143 } else { 2144 return NULL; 2145 } 2146 } 2147} 2148 2149 2150// Signature constraints ensure that callers and callees agree about 2151// the meaning of type names in their signatures. This routine is the 2152// intake for constraints. It collects them from several places: 2153// 2154// * LinkResolver::resolve_method (if check_access is true) requires 2155// that the resolving class (the caller) and the defining class of 2156// the resolved method (the callee) agree on each type in the 2157// method's signature. 2158// 2159// * LinkResolver::resolve_interface_method performs exactly the same 2160// checks. 2161// 2162// * LinkResolver::resolve_field requires that the constant pool 2163// attempting to link to a field agree with the field's defining 2164// class about the type of the field signature. 2165// 2166// * klassVtable::initialize_vtable requires that, when a class 2167// overrides a vtable entry allocated by a superclass, that the 2168// overriding method (i.e., the callee) agree with the superclass 2169// on each type in the method's signature. 2170// 2171// * klassItable::initialize_itable requires that, when a class fills 2172// in its itables, for each non-abstract method installed in an 2173// itable, the method (i.e., the callee) agree with the interface 2174// on each type in the method's signature. 2175// 2176// All those methods have a boolean (check_access, checkconstraints) 2177// which turns off the checks. This is used from specialized contexts 2178// such as bootstrapping, dumping, and debugging. 2179// 2180// No direct constraint is placed between the class and its 2181// supertypes. Constraints are only placed along linked relations 2182// between callers and callees. When a method overrides or implements 2183// an abstract method in a supertype (superclass or interface), the 2184// constraints are placed as if the supertype were the caller to the 2185// overriding method. (This works well, since callers to the 2186// supertype have already established agreement between themselves and 2187// the supertype.) As a result of all this, a class can disagree with 2188// its supertype about the meaning of a type name, as long as that 2189// class neither calls a relevant method of the supertype, nor is 2190// called (perhaps via an override) from the supertype. 2191// 2192// 2193// SystemDictionary::check_signature_loaders(sig, l1, l2) 2194// 2195// Make sure all class components (including arrays) in the given 2196// signature will be resolved to the same class in both loaders. 2197// Returns the name of the type that failed a loader constraint check, or 2198// NULL if no constraint failed. No exception except OOME is thrown. 2199// Arrays are not added to the loader constraint table, their elements are. 2200Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, 2201 Handle loader1, Handle loader2, 2202 bool is_method, TRAPS) { 2203 // Nothing to do if loaders are the same. 2204 if (loader1() == loader2()) { 2205 return NULL; 2206 } 2207 2208 SignatureStream sig_strm(signature, is_method); 2209 while (!sig_strm.is_done()) { 2210 if (sig_strm.is_object()) { 2211 Symbol* sig = sig_strm.as_symbol(CHECK_NULL); 2212 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { 2213 return sig; 2214 } 2215 } 2216 sig_strm.next(); 2217 } 2218 return NULL; 2219} 2220 2221 2222methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, 2223 Symbol* signature, 2224 TRAPS) { 2225 methodHandle empty; 2226 assert(MethodHandles::is_signature_polymorphic(iid) && 2227 MethodHandles::is_signature_polymorphic_intrinsic(iid) && 2228 iid != vmIntrinsics::_invokeGeneric, 2229 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid))); 2230 2231 unsigned int hash = invoke_method_table()->compute_hash(signature, iid); 2232 int index = invoke_method_table()->hash_to_index(hash); 2233 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2234 methodHandle m; 2235 if (spe == NULL || spe->method() == NULL) { 2236 spe = NULL; 2237 // Must create lots of stuff here, but outside of the SystemDictionary lock. 2238 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); 2239 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier, 2240 methodHandle(), CompileThreshold, "MH", CHECK_(empty)); 2241 2242 // Now grab the lock. We might have to throw away the new method, 2243 // if a racing thread has managed to install one at the same time. 2244 { 2245 MutexLocker ml(SystemDictionary_lock, THREAD); 2246 spe = invoke_method_table()->find_entry(index, hash, signature, iid); 2247 if (spe == NULL) 2248 spe = invoke_method_table()->add_entry(index, hash, signature, iid); 2249 if (spe->method() == NULL) 2250 spe->set_method(m()); 2251 } 2252 } 2253 2254 assert(spe != NULL && spe->method() != NULL, ""); 2255 return spe->method(); 2256} 2257 2258// Helper for unpacking the return value from linkMethod and linkCallSite. 2259static methodHandle unpack_method_and_appendix(Handle mname, 2260 KlassHandle accessing_klass, 2261 objArrayHandle appendix_box, 2262 Handle* appendix_result, 2263 TRAPS) { 2264 methodHandle empty; 2265 if (mname.not_null()) { 2266 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname()); 2267 if (vmtarget != NULL && vmtarget->is_method()) { 2268 Method* m = (Method*)vmtarget; 2269 oop appendix = appendix_box->obj_at(0); 2270 if (TraceMethodHandles) { 2271 #ifndef PRODUCT 2272 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); 2273 m->print(); 2274 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } 2275 tty->cr(); 2276 #endif //PRODUCT 2277 } 2278 (*appendix_result) = Handle(THREAD, appendix); 2279 // the target is stored in the cpCache and if a reference to this 2280 // MethodName is dropped we need a way to make sure the 2281 // class_loader containing this method is kept alive. 2282 // FIXME: the appendix might also preserve this dependency. 2283 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data(); 2284 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM 2285 return methodHandle(THREAD, m); 2286 } 2287 } 2288 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); 2289 return empty; 2290} 2291 2292methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name, 2293 Symbol* signature, 2294 KlassHandle accessing_klass, 2295 Handle *appendix_result, 2296 Handle *method_type_result, 2297 TRAPS) { 2298 methodHandle empty; 2299 assert(!THREAD->is_Compiler_thread(), ""); 2300 Handle method_type = 2301 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); 2302 if (false) { // FIXME: Decide if the Java upcall should resolve signatures. 2303 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty)); 2304 } 2305 2306 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass(); 2307 int ref_kind = JVM_REF_invokeVirtual; 2308 Handle name_str = StringTable::intern(name, CHECK_(empty)); 2309 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2310 assert(appendix_box->obj_at(0) == NULL, ""); 2311 2312 // This should not happen. JDK code should take care of that. 2313 if (accessing_klass.is_null() || method_type.is_null()) { 2314 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); 2315 } 2316 2317 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName 2318 JavaCallArguments args; 2319 args.push_oop(accessing_klass()->java_mirror()); 2320 args.push_int(ref_kind); 2321 args.push_oop(mh_klass()->java_mirror()); 2322 args.push_oop(name_str()); 2323 args.push_oop(method_type()); 2324 args.push_oop(appendix_box()); 2325 JavaValue result(T_OBJECT); 2326 JavaCalls::call_static(&result, 2327 SystemDictionary::MethodHandleNatives_klass(), 2328 vmSymbols::linkMethod_name(), 2329 vmSymbols::linkMethod_signature(), 2330 &args, CHECK_(empty)); 2331 Handle mname(THREAD, (oop) result.get_jobject()); 2332 (*method_type_result) = method_type; 2333 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); 2334} 2335 2336 2337// Ask Java code to find or construct a java.lang.invoke.MethodType for the given 2338// signature, as interpreted relative to the given class loader. 2339// Because of class loader constraints, all method handle usage must be 2340// consistent with this loader. 2341Handle SystemDictionary::find_method_handle_type(Symbol* signature, 2342 KlassHandle accessing_klass, 2343 TRAPS) { 2344 Handle empty; 2345 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics 2346 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); 2347 int index = invoke_method_table()->hash_to_index(hash); 2348 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2349 if (spe != NULL && spe->method_type() != NULL) { 2350 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); 2351 return Handle(THREAD, spe->method_type()); 2352 } else if (THREAD->is_Compiler_thread()) { 2353 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME 2354 return Handle(); // do not attempt from within compiler, unless it was cached 2355 } 2356 2357 Handle class_loader, protection_domain; 2358 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader 2359 int npts = ArgumentCount(signature).size(); 2360 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty)); 2361 int arg = 0; 2362 Handle rt; // the return type from the signature 2363 ResourceMark rm(THREAD); 2364 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { 2365 oop mirror = NULL; 2366 if (is_on_bcp) { 2367 // Note: class_loader & protection_domain are both null at this point. 2368 mirror = ss.as_java_mirror(class_loader, protection_domain, 2369 SignatureStream::ReturnNull, CHECK_(empty)); 2370 if (mirror == NULL) { 2371 // fall back from BCP to accessing_klass 2372 if (accessing_klass.not_null()) { 2373 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader()); 2374 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain()); 2375 } 2376 is_on_bcp = false; 2377 } 2378 } 2379 if (!is_on_bcp) { 2380 // Resolve, throwing a real error if it doesn't work. 2381 mirror = ss.as_java_mirror(class_loader, protection_domain, 2382 SignatureStream::NCDFError, CHECK_(empty)); 2383 } 2384 if (ss.at_return_type()) 2385 rt = Handle(THREAD, mirror); 2386 else 2387 pts->obj_at_put(arg++, mirror); 2388 2389 // Check accessibility. 2390 if (ss.is_object() && accessing_klass.not_null()) { 2391 Klass* sel_klass = java_lang_Class::as_Klass(mirror); 2392 mirror = NULL; // safety 2393 // Emulate ConstantPool::verify_constant_pool_resolve. 2394 if (sel_klass->oop_is_objArray()) 2395 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass(); 2396 if (sel_klass->oop_is_instance()) { 2397 KlassHandle sel_kh(THREAD, sel_klass); 2398 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); 2399 } 2400 } 2401 } 2402 assert(arg == npts, ""); 2403 2404 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType 2405 JavaCallArguments args(Handle(THREAD, rt())); 2406 args.push_oop(pts()); 2407 JavaValue result(T_OBJECT); 2408 JavaCalls::call_static(&result, 2409 SystemDictionary::MethodHandleNatives_klass(), 2410 vmSymbols::findMethodHandleType_name(), 2411 vmSymbols::findMethodHandleType_signature(), 2412 &args, CHECK_(empty)); 2413 Handle method_type(THREAD, (oop) result.get_jobject()); 2414 2415 if (is_on_bcp) { 2416 // We can cache this MethodType inside the JVM. 2417 MutexLocker ml(SystemDictionary_lock, THREAD); 2418 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); 2419 if (spe == NULL) 2420 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); 2421 if (spe->method_type() == NULL) { 2422 spe->set_method_type(method_type()); 2423 } 2424 } 2425 2426 // report back to the caller with the MethodType 2427 return method_type; 2428} 2429 2430// Ask Java code to find or construct a method handle constant. 2431Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, 2432 int ref_kind, //e.g., JVM_REF_invokeVirtual 2433 KlassHandle callee, 2434 Symbol* name_sym, 2435 Symbol* signature, 2436 TRAPS) { 2437 Handle empty; 2438 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); 2439 Handle type; 2440 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { 2441 type = find_method_handle_type(signature, caller, CHECK_(empty)); 2442 } else if (caller.is_null()) { 2443 // This should not happen. JDK code should take care of that. 2444 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); 2445 } else { 2446 ResourceMark rm(THREAD); 2447 SignatureStream ss(signature, false); 2448 if (!ss.is_done()) { 2449 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), 2450 SignatureStream::NCDFError, CHECK_(empty)); 2451 type = Handle(THREAD, mirror); 2452 ss.next(); 2453 if (!ss.is_done()) type = Handle(); // error! 2454 } 2455 } 2456 if (type.is_null()) { 2457 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); 2458 } 2459 2460 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle 2461 JavaCallArguments args; 2462 args.push_oop(caller->java_mirror()); // the referring class 2463 args.push_int(ref_kind); 2464 args.push_oop(callee->java_mirror()); // the target class 2465 args.push_oop(name()); 2466 args.push_oop(type()); 2467 JavaValue result(T_OBJECT); 2468 JavaCalls::call_static(&result, 2469 SystemDictionary::MethodHandleNatives_klass(), 2470 vmSymbols::linkMethodHandleConstant_name(), 2471 vmSymbols::linkMethodHandleConstant_signature(), 2472 &args, CHECK_(empty)); 2473 return Handle(THREAD, (oop) result.get_jobject()); 2474} 2475 2476// Ask Java code to find or construct a java.lang.invoke.CallSite for the given 2477// name and signature, as interpreted relative to the given class loader. 2478methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller, 2479 Handle bootstrap_specifier, 2480 Symbol* name, 2481 Symbol* type, 2482 Handle *appendix_result, 2483 Handle *method_type_result, 2484 TRAPS) { 2485 methodHandle empty; 2486 Handle bsm, info; 2487 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { 2488 bsm = bootstrap_specifier; 2489 } else { 2490 assert(bootstrap_specifier->is_objArray(), ""); 2491 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier()); 2492 int len = args->length(); 2493 assert(len >= 1, ""); 2494 bsm = Handle(THREAD, args->obj_at(0)); 2495 if (len > 1) { 2496 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty)); 2497 for (int i = 1; i < len; i++) 2498 args1->obj_at_put(i-1, args->obj_at(i)); 2499 info = Handle(THREAD, args1); 2500 } 2501 } 2502 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), 2503 "caller must supply a valid BSM"); 2504 2505 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); 2506 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); 2507 2508 // This should not happen. JDK code should take care of that. 2509 if (caller.is_null() || method_type.is_null()) { 2510 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); 2511 } 2512 2513 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty)); 2514 assert(appendix_box->obj_at(0) == NULL, ""); 2515 2516 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix) 2517 JavaCallArguments args; 2518 args.push_oop(caller->java_mirror()); 2519 args.push_oop(bsm()); 2520 args.push_oop(method_name()); 2521 args.push_oop(method_type()); 2522 args.push_oop(info()); 2523 args.push_oop(appendix_box); 2524 JavaValue result(T_OBJECT); 2525 JavaCalls::call_static(&result, 2526 SystemDictionary::MethodHandleNatives_klass(), 2527 vmSymbols::linkCallSite_name(), 2528 vmSymbols::linkCallSite_signature(), 2529 &args, CHECK_(empty)); 2530 Handle mname(THREAD, (oop) result.get_jobject()); 2531 (*method_type_result) = method_type; 2532 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); 2533} 2534 2535// Since the identity hash code for symbols changes when the symbols are 2536// moved from the regular perm gen (hash in the mark word) to the shared 2537// spaces (hash is the address), the classes loaded into the dictionary 2538// may be in the wrong buckets. 2539 2540void SystemDictionary::reorder_dictionary() { 2541 dictionary()->reorder_dictionary(); 2542} 2543 2544 2545void SystemDictionary::copy_buckets(char** top, char* end) { 2546 dictionary()->copy_buckets(top, end); 2547} 2548 2549 2550void SystemDictionary::copy_table(char** top, char* end) { 2551 dictionary()->copy_table(top, end); 2552} 2553 2554 2555void SystemDictionary::reverse() { 2556 dictionary()->reverse(); 2557} 2558 2559int SystemDictionary::number_of_classes() { 2560 return dictionary()->number_of_entries(); 2561} 2562 2563 2564// ---------------------------------------------------------------------------- 2565#ifndef PRODUCT 2566 2567void SystemDictionary::print() { 2568 dictionary()->print(); 2569 2570 // Placeholders 2571 GCMutexLocker mu(SystemDictionary_lock); 2572 placeholders()->print(); 2573 2574 // loader constraints - print under SD_lock 2575 constraints()->print(); 2576} 2577 2578#endif 2579 2580void SystemDictionary::verify() { 2581 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); 2582 guarantee(constraints() != NULL, 2583 "Verify of loader constraints failed"); 2584 guarantee(dictionary()->number_of_entries() >= 0 && 2585 placeholders()->number_of_entries() >= 0, 2586 "Verify of system dictionary failed"); 2587 2588 // Verify dictionary 2589 dictionary()->verify(); 2590 2591 GCMutexLocker mu(SystemDictionary_lock); 2592 placeholders()->verify(); 2593 2594 // Verify constraint table 2595 guarantee(constraints() != NULL, "Verify of loader constraints failed"); 2596 constraints()->verify(dictionary(), placeholders()); 2597} 2598 2599// utility function for class load event 2600void SystemDictionary::post_class_load_event(const Ticks& start_time, 2601 instanceKlassHandle k, 2602 Handle initiating_loader) { 2603#if INCLUDE_TRACE 2604 EventClassLoad event(UNTIMED); 2605 if (event.should_commit()) { 2606 event.set_starttime(start_time); 2607 event.set_loadedClass(k()); 2608 oop defining_class_loader = k->class_loader(); 2609 event.set_definingClassLoader(defining_class_loader != NULL ? 2610 defining_class_loader->klass() : (Klass*)NULL); 2611 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader(); 2612 event.set_initiatingClassLoader(class_loader != NULL ? 2613 class_loader->klass() : (Klass*)NULL); 2614 event.commit(); 2615 } 2616#endif /* INCLUDE_TRACE */ 2617} 2618 2619#ifndef PRODUCT 2620 2621// statistics code 2622class ClassStatistics: AllStatic { 2623 private: 2624 static int nclasses; // number of classes 2625 static int nmethods; // number of methods 2626 static int nmethoddata; // number of methodData 2627 static int class_size; // size of class objects in words 2628 static int method_size; // size of method objects in words 2629 static int debug_size; // size of debug info in methods 2630 static int methoddata_size; // size of methodData objects in words 2631 2632 static void do_class(Klass* k) { 2633 nclasses++; 2634 class_size += k->size(); 2635 if (k->oop_is_instance()) { 2636 InstanceKlass* ik = (InstanceKlass*)k; 2637 class_size += ik->methods()->size(); 2638 class_size += ik->constants()->size(); 2639 class_size += ik->local_interfaces()->size(); 2640 class_size += ik->transitive_interfaces()->size(); 2641 // We do not have to count implementors, since we only store one! 2642 // SSS: How should these be accounted now that they have moved? 2643 // class_size += ik->fields()->length(); 2644 } 2645 } 2646 2647 static void do_method(Method* m) { 2648 nmethods++; 2649 method_size += m->size(); 2650 // class loader uses same objArray for empty vectors, so don't count these 2651 if (m->has_stackmap_table()) { 2652 method_size += m->stackmap_data()->size(); 2653 } 2654 2655 MethodData* mdo = m->method_data(); 2656 if (mdo != NULL) { 2657 nmethoddata++; 2658 methoddata_size += mdo->size(); 2659 } 2660 } 2661 2662 public: 2663 static void print() { 2664 SystemDictionary::classes_do(do_class); 2665 SystemDictionary::methods_do(do_method); 2666 tty->print_cr("Class statistics:"); 2667 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); 2668 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, 2669 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); 2670 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); 2671 } 2672}; 2673 2674 2675int ClassStatistics::nclasses = 0; 2676int ClassStatistics::nmethods = 0; 2677int ClassStatistics::nmethoddata = 0; 2678int ClassStatistics::class_size = 0; 2679int ClassStatistics::method_size = 0; 2680int ClassStatistics::debug_size = 0; 2681int ClassStatistics::methoddata_size = 0; 2682 2683void SystemDictionary::print_class_statistics() { 2684 ResourceMark rm; 2685 ClassStatistics::print(); 2686} 2687 2688 2689class MethodStatistics: AllStatic { 2690 public: 2691 enum { 2692 max_parameter_size = 10 2693 }; 2694 private: 2695 2696 static int _number_of_methods; 2697 static int _number_of_final_methods; 2698 static int _number_of_static_methods; 2699 static int _number_of_native_methods; 2700 static int _number_of_synchronized_methods; 2701 static int _number_of_profiled_methods; 2702 static int _number_of_bytecodes; 2703 static int _parameter_size_profile[max_parameter_size]; 2704 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; 2705 2706 static void initialize() { 2707 _number_of_methods = 0; 2708 _number_of_final_methods = 0; 2709 _number_of_static_methods = 0; 2710 _number_of_native_methods = 0; 2711 _number_of_synchronized_methods = 0; 2712 _number_of_profiled_methods = 0; 2713 _number_of_bytecodes = 0; 2714 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; 2715 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; 2716 }; 2717 2718 static void do_method(Method* m) { 2719 _number_of_methods++; 2720 // collect flag info 2721 if (m->is_final() ) _number_of_final_methods++; 2722 if (m->is_static() ) _number_of_static_methods++; 2723 if (m->is_native() ) _number_of_native_methods++; 2724 if (m->is_synchronized()) _number_of_synchronized_methods++; 2725 if (m->method_data() != NULL) _number_of_profiled_methods++; 2726 // collect parameter size info (add one for receiver, if any) 2727 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; 2728 // collect bytecodes info 2729 { 2730 Thread *thread = Thread::current(); 2731 HandleMark hm(thread); 2732 BytecodeStream s(methodHandle(thread, m)); 2733 Bytecodes::Code c; 2734 while ((c = s.next()) >= 0) { 2735 _number_of_bytecodes++; 2736 _bytecodes_profile[c]++; 2737 } 2738 } 2739 } 2740 2741 public: 2742 static void print() { 2743 initialize(); 2744 SystemDictionary::methods_do(do_method); 2745 // generate output 2746 tty->cr(); 2747 tty->print_cr("Method statistics (static):"); 2748 // flag distribution 2749 tty->cr(); 2750 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); 2751 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); 2752 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); 2753 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); 2754 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); 2755 // parameter size profile 2756 tty->cr(); 2757 { int tot = 0; 2758 int avg = 0; 2759 for (int i = 0; i < max_parameter_size; i++) { 2760 int n = _parameter_size_profile[i]; 2761 tot += n; 2762 avg += n*i; 2763 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); 2764 } 2765 assert(tot == _number_of_methods, "should be the same"); 2766 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); 2767 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); 2768 } 2769 // bytecodes profile 2770 tty->cr(); 2771 { int tot = 0; 2772 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { 2773 if (Bytecodes::is_defined(i)) { 2774 Bytecodes::Code c = Bytecodes::cast(i); 2775 int n = _bytecodes_profile[c]; 2776 tot += n; 2777 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); 2778 } 2779 } 2780 assert(tot == _number_of_bytecodes, "should be the same"); 2781 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); 2782 } 2783 tty->cr(); 2784 } 2785}; 2786 2787int MethodStatistics::_number_of_methods; 2788int MethodStatistics::_number_of_final_methods; 2789int MethodStatistics::_number_of_static_methods; 2790int MethodStatistics::_number_of_native_methods; 2791int MethodStatistics::_number_of_synchronized_methods; 2792int MethodStatistics::_number_of_profiled_methods; 2793int MethodStatistics::_number_of_bytecodes; 2794int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; 2795int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; 2796 2797 2798void SystemDictionary::print_method_statistics() { 2799 MethodStatistics::print(); 2800} 2801 2802#endif // PRODUCT 2803