1 /* 2 * Copyright (c) 2014, 2025, 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 26 #include "cds/aotClassFilter.hpp" 27 #include "cds/aotClassLocation.hpp" 28 #include "cds/aotLogging.hpp" 29 #include "cds/aotMetaspace.hpp" 30 #include "cds/archiveBuilder.hpp" 31 #include "cds/archiveUtils.hpp" 32 #include "cds/cdsConfig.hpp" 33 #include "cds/cdsProtectionDomain.hpp" 34 #include "cds/classListParser.hpp" 35 #include "cds/classListWriter.hpp" 36 #include "cds/dumpTimeClassInfo.inline.hpp" 37 #include "cds/dynamicArchive.hpp" 38 #include "cds/filemap.hpp" 39 #include "cds/heapShared.hpp" 40 #include "cds/lambdaFormInvokers.inline.hpp" 41 #include "cds/lambdaProxyClassDictionary.hpp" 42 #include "cds/runTimeClassInfo.hpp" 43 #include "cds/unregisteredClasses.hpp" 44 #include "classfile/classFileStream.hpp" 45 #include "classfile/classLoader.hpp" 46 #include "classfile/classLoaderData.inline.hpp" 47 #include "classfile/classLoaderDataGraph.hpp" 48 #include "classfile/dictionary.hpp" 49 #include "classfile/javaClasses.inline.hpp" 50 #include "classfile/symbolTable.hpp" 51 #include "classfile/systemDictionary.hpp" 52 #include "classfile/systemDictionaryShared.hpp" 53 #include "classfile/verificationType.hpp" 54 #include "classfile/vmClasses.hpp" 55 #include "classfile/vmSymbols.hpp" 56 #include "jfr/jfrEvents.hpp" 57 #include "logging/log.hpp" 58 #include "logging/logStream.hpp" 59 #include "memory/allocation.hpp" 60 #include "memory/metadataFactory.hpp" 61 #include "memory/metaspaceClosure.hpp" 62 #include "memory/oopFactory.hpp" 63 #include "memory/resourceArea.hpp" 64 #include "memory/universe.hpp" 65 #include "oops/compressedKlass.inline.hpp" 66 #include "oops/instanceKlass.hpp" 67 #include "oops/klass.inline.hpp" 68 #include "oops/methodData.hpp" 69 #include "oops/objArrayKlass.hpp" 70 #include "oops/objArrayOop.inline.hpp" 71 #include "oops/oop.inline.hpp" 72 #include "oops/oopHandle.inline.hpp" 73 #include "oops/typeArrayOop.inline.hpp" 74 #include "runtime/arguments.hpp" 75 #include "runtime/handles.inline.hpp" 76 #include "runtime/java.hpp" 77 #include "runtime/javaCalls.hpp" 78 #include "runtime/mutexLocker.hpp" 79 #include "utilities/hashTable.hpp" 80 #include "utilities/stringUtils.hpp" 81 82 SystemDictionaryShared::ArchiveInfo SystemDictionaryShared::_static_archive; 83 SystemDictionaryShared::ArchiveInfo SystemDictionaryShared::_dynamic_archive; 84 85 DumpTimeSharedClassTable* SystemDictionaryShared::_dumptime_table = nullptr; 86 bool SystemDictionaryShared::_finished_exclusion_checks = false; 87 88 // Used by NoClassLoadingMark 89 DEBUG_ONLY(bool SystemDictionaryShared::_class_loading_may_happen = true;) 90 91 #ifdef ASSERT 92 static void check_klass_after_loading(const Klass* k) { 93 #ifdef _LP64 94 if (k != nullptr && UseCompressedClassPointers) { 95 CompressedKlassPointers::check_encodable(k); 96 } 97 #endif 98 } 99 #endif 100 101 InstanceKlass* SystemDictionaryShared::load_shared_class_for_builtin_loader( 102 Symbol* class_name, Handle class_loader, TRAPS) { 103 assert(CDSConfig::is_using_archive(), "must be"); 104 InstanceKlass* ik = find_builtin_class(class_name); 105 106 if (ik != nullptr && !ik->shared_loading_failed()) { 107 if ((SystemDictionary::is_system_class_loader(class_loader()) && ik->defined_by_app_loader()) || 108 (SystemDictionary::is_platform_class_loader(class_loader()) && ik->defined_by_platform_loader())) { 109 SharedClassLoadingMark slm(THREAD, ik); 110 PackageEntry* pkg_entry = CDSProtectionDomain::get_package_entry_from_class(ik, class_loader); 111 Handle protection_domain; 112 if (!class_name->starts_with("jdk/proxy")) // java/lang/reflect/Proxy$ProxyBuilder defines the proxy classes with a null protection domain. 113 { 114 protection_domain = CDSProtectionDomain::init_security_info(class_loader, ik, pkg_entry, CHECK_NULL); 115 } 116 return load_shared_class(ik, class_loader, protection_domain, nullptr, pkg_entry, THREAD); 117 } 118 } 119 return nullptr; 120 } 121 122 // This function is called for loading only UNREGISTERED classes 123 InstanceKlass* SystemDictionaryShared::lookup_from_stream(Symbol* class_name, 124 Handle class_loader, 125 Handle protection_domain, 126 const ClassFileStream* cfs, 127 TRAPS) { 128 if (!CDSConfig::is_using_archive()) { 129 return nullptr; 130 } 131 if (class_name == nullptr) { // don't do this for hidden classes 132 return nullptr; 133 } 134 if (class_loader.is_null() || 135 SystemDictionary::is_system_class_loader(class_loader()) || 136 SystemDictionary::is_platform_class_loader(class_loader())) { 137 // Do nothing for the BUILTIN loaders. 138 return nullptr; 139 } 140 141 const RunTimeClassInfo* record = find_record(&_static_archive._unregistered_dictionary, 142 &_dynamic_archive._unregistered_dictionary, 143 class_name); 144 if (record == nullptr) { 145 return nullptr; 146 } 147 148 int clsfile_size = cfs->length(); 149 int clsfile_crc32 = ClassLoader::crc32(0, (const char*)cfs->buffer(), cfs->length()); 150 151 if (!record->matches(clsfile_size, clsfile_crc32)) { 152 return nullptr; 153 } 154 155 return acquire_class_for_current_thread(record->klass(), class_loader, 156 protection_domain, cfs, 157 THREAD); 158 } 159 160 InstanceKlass* SystemDictionaryShared::acquire_class_for_current_thread( 161 InstanceKlass *ik, 162 Handle class_loader, 163 Handle protection_domain, 164 const ClassFileStream *cfs, 165 TRAPS) { 166 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); 167 168 { 169 MutexLocker mu(THREAD, SharedDictionary_lock); 170 if (ik->class_loader_data() != nullptr) { 171 // ik is already loaded (by this loader or by a different loader) 172 // or ik is being loaded by a different thread (by this loader or by a different loader) 173 return nullptr; 174 } 175 176 // No other thread has acquired this yet, so give it to *this thread* 177 ik->set_class_loader_data(loader_data); 178 } 179 180 // No longer holding SharedDictionary_lock 181 // No need to lock, as <ik> can be held only by a single thread. 182 loader_data->add_class(ik); 183 184 // Get the package entry. 185 PackageEntry* pkg_entry = CDSProtectionDomain::get_package_entry_from_class(ik, class_loader); 186 187 // Load and check super/interfaces, restore unshareable info 188 InstanceKlass* shared_klass = load_shared_class(ik, class_loader, protection_domain, 189 cfs, pkg_entry, THREAD); 190 if (shared_klass == nullptr || HAS_PENDING_EXCEPTION) { 191 // TODO: clean up <ik> so it can be used again 192 return nullptr; 193 } 194 195 return shared_klass; 196 } 197 198 // Guaranteed to return non-null value for non-shared classes. 199 // k must not be a shared class. 200 DumpTimeClassInfo* SystemDictionaryShared::get_info(InstanceKlass* k) { 201 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag); 202 return get_info_locked(k); 203 } 204 205 DumpTimeClassInfo* SystemDictionaryShared::get_info_locked(InstanceKlass* k) { 206 assert_lock_strong(DumpTimeTable_lock); 207 DumpTimeClassInfo* info = _dumptime_table->get_info(k); 208 assert(info != nullptr, "must be"); 209 return info; 210 } 211 212 bool SystemDictionaryShared::should_be_excluded_impl(InstanceKlass* k, DumpTimeClassInfo* info) { 213 assert_lock_strong(DumpTimeTable_lock); 214 215 if (!info->has_checked_exclusion()) { 216 check_exclusion_for_self_and_dependencies(k); 217 assert(info->has_checked_exclusion(), "must be"); 218 } 219 220 return info->is_excluded(); 221 } 222 223 // <func> returns bool and takes a single parameter of Symbol* 224 // The return value indicates whether we want to keep on iterating or not. 225 template<typename Function> 226 void SystemDictionaryShared::iterate_verification_constraint_names(InstanceKlass* k, DumpTimeClassInfo* info, Function func) { 227 int n = info->num_verifier_constraints(); 228 bool cont; // continue iterating? 229 for (int i = 0; i < n; i++) { 230 cont = func(info->verifier_constraint_name_at(i)); 231 if (!cont) { 232 return; // early termination 233 } 234 Symbol* from_name = info->verifier_constraint_from_name_at(i); 235 if (from_name != nullptr) { 236 cont = func(from_name); 237 if (!cont) { 238 return; // early termination 239 } 240 } 241 } 242 } 243 244 // This is a table of classes that need to be checked for exclusion. 245 class SystemDictionaryShared::ExclusionCheckCandidates 246 : public HashTable<InstanceKlass*, DumpTimeClassInfo*, 15889> { 247 void add_candidate(InstanceKlass* k) { 248 if (contains(k)) { 249 return; 250 } 251 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(k)) { 252 return; 253 } 254 255 DumpTimeClassInfo* info = SystemDictionaryShared::get_info_locked(k); 256 if (info->has_checked_exclusion()) { 257 // We have check exclusion of k and all of its dependencies, so there's no need to check again. 258 return; 259 } 260 261 put(k, info); 262 263 if (!k->is_loaded()) { 264 // super types are not yet initialized for k. 265 return; 266 } 267 268 InstanceKlass* super = k->java_super(); 269 if (super != nullptr) { 270 add_candidate(super); 271 } 272 273 Array<InstanceKlass*>* interfaces = k->local_interfaces(); 274 int len = interfaces->length(); 275 for (int i = 0; i < len; i++) { 276 add_candidate(interfaces->at(i)); 277 } 278 279 InstanceKlass* nest_host = k->nest_host_or_null(); 280 if (nest_host != nullptr && nest_host != k) { 281 add_candidate(nest_host); 282 } 283 284 if (CDSConfig::is_preserving_verification_constraints()) { 285 SystemDictionaryShared::iterate_verification_constraint_names(k, info, [&] (Symbol* constraint_class_name) { 286 Klass* constraint_bottom_class = find_verification_constraint_bottom_class(k, constraint_class_name); 287 if (constraint_bottom_class != nullptr && constraint_bottom_class->is_instance_klass()) { 288 add_candidate(InstanceKlass::cast(constraint_bottom_class)); 289 } 290 return true; // Keep iterating. 291 }); 292 } 293 } 294 295 public: 296 ExclusionCheckCandidates(InstanceKlass* k) { 297 add_candidate(k); 298 } 299 }; 300 301 // A class X is excluded if check_self_exclusion() returns true for X or any of 302 // X's "exclusion dependency" classes, which include: 303 // - ik's super types 304 // - ik's nest host (if any) 305 // 306 // plus, if CDSConfig::is_preserving_verification_constraints()==true: 307 // - ik's verification constraints. These are the classes used in assignability checks 308 // when verifying ik's bytecodes. 309 // 310 // This method ensure that exclusion check is performed on X and all of its exclusion dependencies. 311 void SystemDictionaryShared::check_exclusion_for_self_and_dependencies(InstanceKlass* ik) { 312 assert_lock_strong(DumpTimeTable_lock); 313 ResourceMark rm; 314 315 // This will recursively find ik and all of its exclusion dependencies that have not yet been checked. 316 ExclusionCheckCandidates candidates(ik); 317 318 // (1) Check each class to see if it should be excluded due to its own problems 319 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) { 320 if (check_self_exclusion(k)) { 321 info->set_excluded(); 322 } 323 }); 324 325 // (2) Check each class to see if it should be excluded because of problems in a depeendency class 326 while (true) { 327 bool found_new_exclusion = false; 328 329 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) { 330 if (!info->is_excluded() && check_dependencies_exclusion(k, info)) { 331 info->set_excluded(); 332 found_new_exclusion = true; 333 } 334 }); 335 336 // Algorithm notes: 337 // 338 // The dependencies form a directed graph, possibly cyclic. Class X is excluded 339 // if it has at least one directed path that reaches class Y, where 340 // check_self_exclusion(Y) returns true. 341 // 342 // Because of the possibility of cycles in the graph, we cannot use simple 343 // recursion. Otherwise we will either never terminate, or will miss some paths. 344 // 345 // Hence, we keep doing a linear scan of the candidates until we stop finding 346 // new exclusions. 347 // 348 // In the worst case, we find one exclusion per iteration of the while loop, 349 // so the while loop gets executed O(N^2) times. However, in reality we have 350 // very few exclusions, so in most cases the while loop executes only once, and we 351 // walk each edge in the dependencies graph exactly once. 352 if (!found_new_exclusion) { 353 break; 354 } 355 } 356 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) { 357 // All candidates have been fully checked, so we don't need to check them again. 358 info->set_has_checked_exclusion(); 359 }); 360 } 361 362 // Returns true so the caller can do: return warn_excluded("....."); 363 bool SystemDictionaryShared::warn_excluded(InstanceKlass* k, const char* reason) { 364 ResourceMark rm; 365 aot_log_warning(aot)("Skipping %s: %s", k->name()->as_C_string(), reason); 366 return true; 367 } 368 369 bool SystemDictionaryShared::is_jfr_event_class(InstanceKlass *k) { 370 while (k) { 371 if (k->name()->equals("jdk/internal/event/Event")) { 372 return true; 373 } 374 k = k->super(); 375 } 376 return false; 377 } 378 379 bool SystemDictionaryShared::is_early_klass(InstanceKlass* ik) { 380 DumpTimeClassInfo* info = _dumptime_table->get(ik); 381 return (info != nullptr) ? info->is_early_klass() : false; 382 } 383 384 bool SystemDictionaryShared::check_self_exclusion(InstanceKlass* k) { 385 assert_lock_strong(DumpTimeTable_lock); 386 if (CDSConfig::is_dumping_final_static_archive() && k->defined_by_other_loaders() 387 && k->in_aot_cache()) { 388 return false; // Do not exclude: unregistered classes are passed from preimage to final image. 389 } 390 391 if (k->is_in_error_state()) { 392 return warn_excluded(k, "In error state"); 393 } 394 if (k->is_scratch_class()) { 395 return warn_excluded(k, "A scratch class"); 396 } 397 if (!k->is_loaded()) { 398 return warn_excluded(k, "Not in loaded state"); 399 } 400 if (has_been_redefined(k)) { 401 return warn_excluded(k, "Has been redefined"); 402 } 403 if (!k->is_hidden() && k->shared_classpath_index() < 0 && is_builtin(k)) { 404 if (k->name()->starts_with("java/lang/invoke/BoundMethodHandle$Species_")) { 405 // This class is dynamically generated by the JDK 406 if (CDSConfig::is_dumping_method_handles()) { 407 k->set_shared_classpath_index(0); 408 } else { 409 ResourceMark rm; 410 aot_log_info(aot)("Skipping %s because it is dynamically generated", k->name()->as_C_string()); 411 return true; // exclude without warning 412 } 413 } else { 414 // These are classes loaded from unsupported locations (such as those loaded by JVMTI native 415 // agent during dump time). 416 return warn_excluded(k, "Unsupported location"); 417 } 418 } 419 if (k->signers() != nullptr) { 420 // We cannot include signed classes in the archive because the certificates 421 // used during dump time may be different than those used during 422 // runtime (due to expiration, etc). 423 return warn_excluded(k, "Signed JAR"); 424 } 425 if (is_jfr_event_class(k)) { 426 // We cannot include JFR event classes because they need runtime-specific 427 // instrumentation in order to work with -XX:FlightRecorderOptions:retransform=false. 428 // There are only a small number of these classes, so it's not worthwhile to 429 // support them and make CDS more complicated. 430 return warn_excluded(k, "JFR event class"); 431 } 432 433 if (!k->is_linked()) { 434 if (has_class_failed_verification(k)) { 435 return warn_excluded(k, "Failed verification"); 436 } else if (CDSConfig::is_dumping_aot_linked_classes()) { 437 // Most loaded classes should have been speculatively linked by AOTMetaspace::link_class_for_cds(). 438 // Old classes may not be linked if CDSConfig::is_preserving_verification_constraints()==false. 439 // An unlinked class may fail to verify in AOTLinkedClassBulkLoader::init_required_classes_for_loader(), 440 // causing the JVM to fail at bootstrap. 441 return warn_excluded(k, "Unlinked class not supported by AOTClassLinking"); 442 } else if (CDSConfig::is_dumping_preimage_static_archive()) { 443 // When dumping the final static archive, we will unconditionally load and link all 444 // classes from the preimage. We don't want to get a VerifyError when linking this class. 445 return warn_excluded(k, "Unlinked class not supported by AOTConfiguration"); 446 } 447 } else { 448 if (!k->can_be_verified_at_dumptime()) { 449 // We have an old class that has been linked (e.g., it's been executed during 450 // dump time). This class has been verified using the old verifier, which 451 // doesn't save the verification constraints, so check_verification_constraints() 452 // won't work at runtime. 453 // As a result, we cannot store this class. It must be loaded and fully verified 454 // at runtime. 455 return warn_excluded(k, "Old class has been linked"); 456 } 457 } 458 459 if (UnregisteredClasses::check_for_exclusion(k)) { 460 ResourceMark rm; 461 aot_log_info(aot)("Skipping %s: used only when dumping CDS archive", k->name()->as_C_string()); 462 return true; 463 } 464 465 return false; 466 } 467 468 // Returns true if DumpTimeClassInfo::is_excluded() is true for at least one of k's exclusion dependencies. 469 bool SystemDictionaryShared::check_dependencies_exclusion(InstanceKlass* k, DumpTimeClassInfo* info) { 470 InstanceKlass* super = k->java_super(); 471 if (super != nullptr && is_dependency_excluded(k, super, "super")) { 472 return true; 473 } 474 475 Array<InstanceKlass*>* interfaces = k->local_interfaces(); 476 int len = interfaces->length(); 477 for (int i = 0; i < len; i++) { 478 InstanceKlass* intf = interfaces->at(i); 479 if (is_dependency_excluded(k, intf, "interface")) { 480 return true; 481 } 482 } 483 484 InstanceKlass* nest_host = k->nest_host_or_null(); 485 if (nest_host != nullptr && nest_host != k && is_dependency_excluded(k, nest_host, "nest host class")) { 486 return true; 487 } 488 489 if (CDSConfig::is_preserving_verification_constraints()) { 490 bool excluded = false; 491 492 iterate_verification_constraint_names(k, info, [&] (Symbol* constraint_class_name) { 493 if (check_verification_constraint_exclusion(k, constraint_class_name)) { 494 // If one of the verification constraint class has been excluded, the assignability checks 495 // by the verifier may no longer be valid in the production run. For safety, exclude this class. 496 excluded = true; 497 return false; // terminate iteration; k will be excluded 498 } else { 499 return true; // keep iterating 500 } 501 }); 502 503 if (excluded) { 504 // At least one verification constraint class has been excluded 505 return true; 506 } 507 } 508 509 return false; 510 } 511 512 bool SystemDictionaryShared::is_dependency_excluded(InstanceKlass* k, InstanceKlass* dependency, const char* type) { 513 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(dependency)) { 514 return false; 515 } 516 DumpTimeClassInfo* dependency_info = get_info_locked(dependency); 517 if (dependency_info->is_excluded()) { 518 ResourceMark rm; 519 aot_log_warning(aot)("Skipping %s: %s %s is excluded", k->name()->as_C_string(), type, dependency->name()->as_C_string()); 520 return true; 521 } 522 return false; 523 } 524 525 bool SystemDictionaryShared::check_verification_constraint_exclusion(InstanceKlass* k, Symbol* constraint_class_name) { 526 Klass* constraint_bottom_class = find_verification_constraint_bottom_class(k, constraint_class_name); 527 if (constraint_bottom_class == nullptr) { 528 // We don't have a bottom class (constraint_class_name is a type array), or constraint_class_name 529 // has not been loaded. The latter case happens when the new verifier was checking 530 // if constraint_class_name is assignable to an interface, and found the answer without resolving 531 // constraint_class_name. 532 // 533 // Since this class is not even loaded, it surely cannot be excluded. 534 return false; 535 } else if (constraint_bottom_class->is_instance_klass()) { 536 if (is_dependency_excluded(k, InstanceKlass::cast(constraint_bottom_class), "verification constraint")) { 537 return true; 538 } 539 } else { 540 assert(constraint_bottom_class->is_typeArray_klass(), "must be"); 541 } 542 543 return false; 544 } 545 546 Klass* SystemDictionaryShared::find_verification_constraint_bottom_class(InstanceKlass* k, Symbol* constraint_class_name) { 547 Thread* current = Thread::current(); 548 Handle loader(current, k->class_loader()); 549 Klass* constraint_class = SystemDictionary::find_instance_or_array_klass(current, constraint_class_name, loader); 550 if (constraint_class == nullptr) { 551 return nullptr; 552 } 553 554 if (constraint_class->is_objArray_klass()) { 555 constraint_class = ObjArrayKlass::cast(constraint_class)->bottom_klass(); 556 } 557 558 precond(constraint_class->is_typeArray_klass() || constraint_class->is_instance_klass()); 559 return constraint_class; 560 } 561 562 bool SystemDictionaryShared::is_builtin_loader(ClassLoaderData* loader_data) { 563 oop class_loader = loader_data->class_loader(); 564 return (class_loader == nullptr || 565 SystemDictionary::is_system_class_loader(class_loader) || 566 SystemDictionary::is_platform_class_loader(class_loader)); 567 } 568 569 bool SystemDictionaryShared::has_platform_or_app_classes() { 570 if (FileMapInfo::current_info()->has_platform_or_app_classes()) { 571 return true; 572 } 573 if (DynamicArchive::is_mapped() && 574 FileMapInfo::dynamic_info()->has_platform_or_app_classes()) { 575 return true; 576 } 577 return false; 578 } 579 580 // The following stack shows how this code is reached: 581 // 582 // [0] SystemDictionaryShared::find_or_load_shared_class() 583 // [1] JVM_FindLoadedClass 584 // [2] java.lang.ClassLoader.findLoadedClass0() 585 // [3] java.lang.ClassLoader.findLoadedClass() 586 // [4] jdk.internal.loader.BuiltinClassLoader.loadClassOrNull() 587 // [5] jdk.internal.loader.BuiltinClassLoader.loadClass() 588 // [6] jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(), or 589 // jdk.internal.loader.ClassLoaders$PlatformClassLoader.loadClass() 590 // 591 // AppCDS supports fast class loading for these 2 built-in class loaders: 592 // jdk.internal.loader.ClassLoaders$PlatformClassLoader 593 // jdk.internal.loader.ClassLoaders$AppClassLoader 594 // with the following assumptions (based on the JDK core library source code): 595 // 596 // [a] these two loaders use the BuiltinClassLoader.loadClassOrNull() to 597 // load the named class. 598 // [b] BuiltinClassLoader.loadClassOrNull() first calls findLoadedClass(name). 599 // [c] At this point, if we can find the named class inside the 600 // shared_dictionary, we can perform further checks (see 601 // SystemDictionary::is_shared_class_visible) to ensure that this class 602 // was loaded by the same class loader during dump time. 603 // 604 // Given these assumptions, we intercept the findLoadedClass() call to invoke 605 // SystemDictionaryShared::find_or_load_shared_class() to load the shared class from 606 // the archive for the 2 built-in class loaders. This way, 607 // we can improve start-up because we avoid decoding the classfile, 608 // and avoid delegating to the parent loader. 609 // 610 // NOTE: there's a lot of assumption about the Java code. If any of that change, this 611 // needs to be redesigned. 612 613 InstanceKlass* SystemDictionaryShared::find_or_load_shared_class( 614 Symbol* name, Handle class_loader, TRAPS) { 615 InstanceKlass* k = nullptr; 616 if (CDSConfig::is_using_archive()) { 617 if (!has_platform_or_app_classes()) { 618 return nullptr; 619 } 620 621 if (SystemDictionary::is_system_class_loader(class_loader()) || 622 SystemDictionary::is_platform_class_loader(class_loader())) { 623 ClassLoaderData *loader_data = register_loader(class_loader); 624 Dictionary* dictionary = loader_data->dictionary(); 625 626 // Note: currently, find_or_load_shared_class is called only from 627 // JVM_FindLoadedClass and used for PlatformClassLoader and AppClassLoader, 628 // which are parallel-capable loaders, so a lock here is NOT taken. 629 assert(get_loader_lock_or_null(class_loader) == nullptr, "ObjectLocker not required"); 630 { 631 MutexLocker mu(THREAD, SystemDictionary_lock); 632 InstanceKlass* check = dictionary->find_class(THREAD, name); 633 if (check != nullptr) { 634 return check; 635 } 636 } 637 638 k = load_shared_class_for_builtin_loader(name, class_loader, THREAD); 639 if (k != nullptr) { 640 SharedClassLoadingMark slm(THREAD, k); 641 k = find_or_define_instance_class(name, class_loader, k, CHECK_NULL); 642 } 643 } 644 } 645 646 DEBUG_ONLY(check_klass_after_loading(k);) 647 648 return k; 649 } 650 651 class UnregisteredClassesTable : public HashTable< 652 Symbol*, InstanceKlass*, 653 15889, // prime number 654 AnyObj::C_HEAP> {}; 655 656 static UnregisteredClassesTable* _unregistered_classes_table = nullptr; 657 658 // true == class was successfully added; false == a duplicated class (with the same name) already exists. 659 bool SystemDictionaryShared::add_unregistered_class(Thread* current, InstanceKlass* klass) { 660 // We don't allow duplicated unregistered classes with the same name. 661 // We only archive the first class with that name that succeeds putting 662 // itself into the table. 663 assert(CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled(), "sanity"); 664 MutexLocker ml(current, UnregisteredClassesTable_lock, Mutex::_no_safepoint_check_flag); 665 Symbol* name = klass->name(); 666 if (_unregistered_classes_table == nullptr) { 667 _unregistered_classes_table = new (mtClass)UnregisteredClassesTable(); 668 } 669 bool created; 670 InstanceKlass** v = _unregistered_classes_table->put_if_absent(name, klass, &created); 671 if (created) { 672 name->increment_refcount(); 673 } 674 return (klass == *v); 675 } 676 677 InstanceKlass* SystemDictionaryShared::get_unregistered_class(Symbol* name) { 678 assert(CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled(), "sanity"); 679 if (_unregistered_classes_table == nullptr) { 680 return nullptr; 681 } 682 InstanceKlass** k = _unregistered_classes_table->get(name); 683 return k != nullptr ? *k : nullptr; 684 } 685 686 void SystemDictionaryShared::copy_unregistered_class_size_and_crc32(InstanceKlass* klass) { 687 precond(CDSConfig::is_dumping_final_static_archive()); 688 precond(klass->in_aot_cache()); 689 690 // A shared class must have a RunTimeClassInfo record 691 const RunTimeClassInfo* record = find_record(&_static_archive._unregistered_dictionary, 692 nullptr, klass->name()); 693 precond(record != nullptr); 694 precond(record->klass() == klass); 695 696 DumpTimeClassInfo* info = get_info(klass); 697 info->_clsfile_size = record->crc()->_clsfile_size; 698 info->_clsfile_crc32 = record->crc()->_clsfile_crc32; 699 } 700 701 void SystemDictionaryShared::set_shared_class_misc_info(InstanceKlass* k, ClassFileStream* cfs) { 702 assert(CDSConfig::is_dumping_archive(), "sanity"); 703 assert(!is_builtin(k), "must be unregistered class"); 704 DumpTimeClassInfo* info = get_info(k); 705 info->_clsfile_size = cfs->length(); 706 info->_clsfile_crc32 = ClassLoader::crc32(0, (const char*)cfs->buffer(), cfs->length()); 707 } 708 709 void SystemDictionaryShared::initialize() { 710 if (CDSConfig::is_dumping_archive()) { 711 _dumptime_table = new (mtClass) DumpTimeSharedClassTable; 712 LambdaProxyClassDictionary::dumptime_init(); 713 if (CDSConfig::is_dumping_heap()) { 714 HeapShared::init_dumping(); 715 } 716 } 717 } 718 719 void SystemDictionaryShared::init_dumptime_info(InstanceKlass* k) { 720 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag); 721 assert(SystemDictionaryShared::class_loading_may_happen(), "sanity"); 722 DumpTimeClassInfo* info = _dumptime_table->allocate_info(k); 723 if (AOTClassFilter::is_aot_tooling_class(k)) { 724 info->set_is_aot_tooling_class(); 725 } 726 } 727 728 void SystemDictionaryShared::remove_dumptime_info(InstanceKlass* k) { 729 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag); 730 _dumptime_table->remove(k); 731 } 732 733 void SystemDictionaryShared::handle_class_unloading(InstanceKlass* klass) { 734 if (CDSConfig::is_dumping_archive()) { 735 remove_dumptime_info(klass); 736 } 737 738 if (CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled()) { 739 MutexLocker ml(Thread::current(), UnregisteredClassesTable_lock, Mutex::_no_safepoint_check_flag); 740 if (_unregistered_classes_table != nullptr) { 741 // Remove the class from _unregistered_classes_table: keep the entry but 742 // set it to null. This ensure no classes with the same name can be 743 // added again. 744 InstanceKlass** v = _unregistered_classes_table->get(klass->name()); 745 if (v != nullptr) { 746 *v = nullptr; 747 } 748 } 749 } else { 750 assert(_unregistered_classes_table == nullptr, "must not be used"); 751 } 752 753 if (ClassListWriter::is_enabled()) { 754 ClassListWriter cw; 755 cw.handle_class_unloading((const InstanceKlass*)klass); 756 } 757 } 758 759 void SystemDictionaryShared::init_dumptime_info_from_preimage(InstanceKlass* k) { 760 init_dumptime_info(k); 761 copy_verification_info_from_preimage(k); 762 copy_linking_constraints_from_preimage(k); 763 764 if (SystemDictionary::is_platform_class_loader(k->class_loader())) { 765 AOTClassLocationConfig::dumptime_set_has_platform_classes(); 766 } else if (SystemDictionary::is_system_class_loader(k->class_loader())) { 767 AOTClassLocationConfig::dumptime_set_has_app_classes(); 768 } 769 } 770 771 // Check if a class or any of its supertypes has been redefined. 772 bool SystemDictionaryShared::has_been_redefined(InstanceKlass* k) { 773 if (k->has_been_redefined()) { 774 return true; 775 } 776 if (k->super() != nullptr && has_been_redefined(k->super())) { 777 return true; 778 } 779 Array<InstanceKlass*>* interfaces = k->local_interfaces(); 780 int len = interfaces->length(); 781 for (int i = 0; i < len; i++) { 782 if (has_been_redefined(interfaces->at(i))) { 783 return true; 784 } 785 } 786 return false; 787 } 788 789 // k is a class before relocating by ArchiveBuilder 790 void SystemDictionaryShared::validate_before_archiving(InstanceKlass* k) { 791 ResourceMark rm; 792 const char* name = k->name()->as_C_string(); 793 DumpTimeClassInfo* info = _dumptime_table->get(k); 794 assert(!class_loading_may_happen(), "class loading must be disabled"); 795 guarantee(info != nullptr, "Class %s must be entered into _dumptime_table", name); 796 guarantee(!info->is_excluded(), "Should not attempt to archive excluded class %s", name); 797 if (is_builtin(k)) { 798 if (k->is_hidden()) { 799 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) { 800 assert(LambdaProxyClassDictionary::is_registered_lambda_proxy_class(k), "unexpected hidden class %s", name); 801 } 802 } 803 guarantee(!k->defined_by_other_loaders(), 804 "Class loader type must be set for BUILTIN class %s", name); 805 806 } else { 807 guarantee(k->defined_by_other_loaders(), 808 "Class loader type must not be set for UNREGISTERED class %s", name); 809 } 810 } 811 812 class UnregisteredClassesDuplicationChecker : StackObj { 813 GrowableArray<InstanceKlass*> _list; 814 Thread* _thread; 815 public: 816 UnregisteredClassesDuplicationChecker() : _thread(Thread::current()) {} 817 818 void do_entry(InstanceKlass* k, DumpTimeClassInfo& info) { 819 if (!SystemDictionaryShared::is_builtin(k)) { 820 _list.append(k); 821 } 822 } 823 824 static int compare_by_loader(InstanceKlass** a, InstanceKlass** b) { 825 ClassLoaderData* loader_a = a[0]->class_loader_data(); 826 ClassLoaderData* loader_b = b[0]->class_loader_data(); 827 828 if (loader_a != loader_b) { 829 return primitive_compare(loader_a, loader_b); 830 } else { 831 return primitive_compare(a[0], b[0]); 832 } 833 } 834 835 void mark_duplicated_classes() { 836 // Two loaders may load two identical or similar hierarchies of classes. If we 837 // check for duplication in random order, we may end up excluding important base classes 838 // in both hierarchies, causing most of the classes to be excluded. 839 // We sort the classes by their loaders. This way we're likely to archive 840 // all classes in the one of the two hierarchies. 841 _list.sort(compare_by_loader); 842 for (int i = 0; i < _list.length(); i++) { 843 InstanceKlass* k = _list.at(i); 844 bool i_am_first = SystemDictionaryShared::add_unregistered_class(_thread, k); 845 if (!i_am_first) { 846 SystemDictionaryShared::warn_excluded(k, "Duplicated unregistered class"); 847 SystemDictionaryShared::set_excluded_locked(k); 848 } 849 } 850 } 851 }; 852 853 // Returns true if the class should be excluded. This can be called by 854 // AOTConstantPoolResolver before or after we enter the CDS safepoint. 855 // When called before the safepoint, we need to link the class so that 856 // it can be checked by should_be_excluded_impl(). 857 bool SystemDictionaryShared::should_be_excluded(Klass* k) { 858 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(k)) { 859 // We have reached a super type that's already in the base archive. Treat it 860 // as "not excluded". 861 return false; 862 } 863 864 if (k->is_objArray_klass()) { 865 return should_be_excluded(ObjArrayKlass::cast(k)->bottom_klass()); 866 } else if (!k->is_instance_klass()) { 867 assert(k->is_typeArray_klass(), "must be"); 868 return false; 869 } else { 870 InstanceKlass* ik = InstanceKlass::cast(k); 871 872 if (CDSConfig::is_dumping_final_static_archive() && _finished_exclusion_checks && 873 !SafepointSynchronize::is_at_safepoint()) { 874 // This is called from the AOT compiler. 875 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag); 876 DumpTimeClassInfo* p = get_info_locked(ik); 877 if (p->is_excluded()) { 878 return true; 879 } else if (!p->has_checked_exclusion()) { 880 // This is a class that was loaded after we exited the AOT safepoint. This 881 // class is not in the AOT cache, so it must be considered as "excluded" 882 return true; 883 } else { 884 return false; 885 } 886 } 887 888 assert(CDSConfig::is_dumping_archive(), "sanity"); 889 assert(CDSConfig::current_thread_is_vm_or_dumper(), "sanity"); 890 891 if (!SafepointSynchronize::is_at_safepoint()) { 892 if (!ik->is_linked()) { 893 // should_be_excluded_impl() below doesn't link unlinked classes. We come 894 // here only when we are trying to aot-link constant pool entries, so 895 // we'd better link the class. 896 JavaThread* THREAD = JavaThread::current(); 897 ik->link_class(THREAD); 898 if (HAS_PENDING_EXCEPTION) { 899 CLEAR_PENDING_EXCEPTION; 900 return true; // linking failed -- let's exclude it 901 } 902 903 // Also link any classes that were loaded for the verification of ik or its supertypes. 904 // Otherwise we might miss the verification constraints of those classes. 905 AOTMetaspace::link_all_loaded_classes(THREAD); 906 } 907 908 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag); 909 DumpTimeClassInfo* p = get_info_locked(ik); 910 if (p->is_excluded()) { 911 return true; 912 } 913 return should_be_excluded_impl(ik, p); 914 } else { 915 // When called within the CDS safepoint, the correctness of this function 916 // relies on the call to AOTMetaspace::link_all_loaded_classes() 917 // that happened right before we enter the CDS safepoint. 918 // 919 // Do not call this function in other types of safepoints. For example, if this 920 // is called in a GC safepoint, a klass may be improperly excluded because some 921 // of its verification constraints have not yet been linked. 922 assert(CDSConfig::is_at_aot_safepoint(), "Do not call this function in any other safepoint"); 923 924 // No need to check for is_linked() as all eligible classes should have 925 // already been linked in AOTMetaspace::link_class_for_cds(). 926 // Can't take the lock as we are in safepoint. 927 DumpTimeClassInfo* p = _dumptime_table->get(ik); 928 if (p->is_excluded()) { 929 return true; 930 } 931 return should_be_excluded_impl(ik, p); 932 } 933 } 934 } 935 936 void SystemDictionaryShared::finish_exclusion_checks() { 937 assert_at_safepoint(); 938 if (CDSConfig::is_dumping_dynamic_archive() || CDSConfig::is_dumping_preimage_static_archive()) { 939 // Do this first -- if a base class is excluded due to duplication, 940 // all of its subclasses will also be excluded. 941 ResourceMark rm; 942 UnregisteredClassesDuplicationChecker dup_checker; 943 _dumptime_table->iterate_all_live_classes(&dup_checker); 944 dup_checker.mark_duplicated_classes(); 945 } 946 947 _dumptime_table->iterate_all_live_classes([&] (InstanceKlass* k, DumpTimeClassInfo& info) { 948 SystemDictionaryShared::should_be_excluded_impl(k, &info); 949 }); 950 951 _dumptime_table->update_counts(); 952 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) { 953 LambdaProxyClassDictionary::cleanup_dumptime_table(); 954 } 955 _finished_exclusion_checks = true; 956 } 957 958 bool SystemDictionaryShared::is_excluded_class(InstanceKlass* k) { 959 assert(!class_loading_may_happen(), "class loading must be disabled"); 960 assert_lock_strong(DumpTimeTable_lock); 961 assert(CDSConfig::is_dumping_archive(), "sanity"); 962 DumpTimeClassInfo* p = get_info_locked(k); 963 return p->is_excluded(); 964 } 965 966 void SystemDictionaryShared::set_excluded_locked(InstanceKlass* k) { 967 assert_lock_strong(DumpTimeTable_lock); 968 assert(CDSConfig::is_dumping_archive(), "sanity"); 969 DumpTimeClassInfo* info = get_info_locked(k); 970 info->set_excluded(); 971 } 972 973 void SystemDictionaryShared::set_excluded(InstanceKlass* k) { 974 assert(CDSConfig::is_dumping_archive(), "sanity"); 975 DumpTimeClassInfo* info = get_info(k); 976 info->set_excluded(); 977 } 978 979 void SystemDictionaryShared::set_class_has_failed_verification(InstanceKlass* ik) { 980 assert(CDSConfig::is_dumping_archive(), "sanity"); 981 DumpTimeClassInfo* p = get_info(ik); 982 p->set_failed_verification(); 983 } 984 985 bool SystemDictionaryShared::has_class_failed_verification(InstanceKlass* ik) { 986 assert(CDSConfig::is_dumping_archive(), "sanity"); 987 DumpTimeClassInfo* p = _dumptime_table->get(ik); 988 return (p == nullptr) ? false : p->failed_verification(); 989 } 990 991 void SystemDictionaryShared::set_from_class_file_load_hook(InstanceKlass* ik) { 992 warn_excluded(ik, "From ClassFileLoadHook"); 993 set_excluded(ik); 994 } 995 996 void SystemDictionaryShared::dumptime_classes_do(MetaspaceClosure* it) { 997 assert_lock_strong(DumpTimeTable_lock); 998 999 auto do_klass = [&] (InstanceKlass* k, DumpTimeClassInfo& info) { 1000 if (CDSConfig::is_dumping_final_static_archive() && !k->is_loaded()) { 1001 assert(k->defined_by_other_loaders(), "must be"); 1002 info.metaspace_pointers_do(it); 1003 } else if (k->is_loader_alive() && !info.is_excluded()) { 1004 info.metaspace_pointers_do(it); 1005 } 1006 }; 1007 _dumptime_table->iterate_all_live_classes(do_klass); 1008 1009 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) { 1010 LambdaProxyClassDictionary::dumptime_classes_do(it); 1011 } 1012 } 1013 1014 // Called from VerificationType::is_reference_assignable_from() before performing the assignability check of 1015 // T1 must be assignable from T2 1016 // Where: 1017 // L is the class loader of <k> 1018 // T1 is the type resolved by L using the name <name> 1019 // T2 is the type resolved by L using the name <from_name> 1020 // 1021 // The meaning of (*skip_assignability_check): 1022 // true: is_reference_assignable_from() should SKIP the assignability check 1023 // false: is_reference_assignable_from() should COMPLETE the assignability check 1024 void SystemDictionaryShared::add_verification_constraint(InstanceKlass* k, Symbol* name, 1025 Symbol* from_name, bool from_field_is_protected, bool from_is_array, bool from_is_object, 1026 bool* skip_assignability_check) { 1027 assert(CDSConfig::is_dumping_archive(), "sanity"); 1028 if (CDSConfig::is_dumping_dynamic_archive() && k->in_aot_cache()) { 1029 // k is a new class in the static archive, but one of its supertypes is an old class, so k wasn't 1030 // verified during dump time. No need to record constraints as k won't be included in the dynamic archive. 1031 return; 1032 } 1033 if (CDSConfig::is_dumping_aot_linked_classes() && is_builtin(k)) { 1034 // There's no need to save verification constraints 1035 // TODO -- double check the logic before integrating into mainline!! 1036 return; 1037 } 1038 1039 DumpTimeClassInfo* info = get_info(k); 1040 info->add_verification_constraint(name, from_name, from_field_is_protected, 1041 from_is_array, from_is_object); 1042 1043 if (CDSConfig::is_dumping_classic_static_archive() && !is_builtin(k)) { 1044 // This applies ONLY to the "classic" CDS static dump, which reads the list of 1045 // unregistered classes (those intended for custom class loaders) from the classlist 1046 // and loads them using jdk.internal.misc.CDS$UnregisteredClassLoader. 1047 // 1048 // When the classlist contains an unregistered class k, the supertypes of k are also 1049 // recorded in the classlist. However, the classlist does not contain information about 1050 // any class X that's not a supertype of k but is needed in the verification of k. 1051 // As a result, CDS$UnregisteredClassLoader will not know how to resolve X. 1052 // 1053 // Therefore, we tell the verifier to refrain from resolving X. Instead, X is recorded 1054 // (symbolically) in the verification constraints of k. In the production run, 1055 // when k is loaded, we will go through its verification constraints and resolve X to complete 1056 // the is_reference_assignable_from() checks. 1057 *skip_assignability_check = true; 1058 } else { 1059 // In all other cases, we are using an *actual* class loader to load k, so it should be able 1060 // to resolve any types that are needed for the verification of k. 1061 *skip_assignability_check = false; 1062 } 1063 } 1064 1065 // When the old verifier is verifying the class <ik> at dump time, it tries to resolve a 1066 // class with the given <name>. For the verification result to be valid at run time, we must 1067 // ensure that <name> resolves to the exact same Klass as in dump time. 1068 void SystemDictionaryShared::add_old_verification_constraint(Thread* current, InstanceKlass* ik, Symbol* name) { 1069 precond(CDSConfig::is_preserving_verification_constraints()); 1070 DumpTimeClassInfo* info = get_info(ik); 1071 info->add_verification_constraint(name); 1072 } 1073 1074 void SystemDictionaryShared::add_enum_klass_static_field(InstanceKlass* ik, int root_index) { 1075 assert(CDSConfig::is_dumping_heap(), "sanity"); 1076 DumpTimeClassInfo* info = get_info_locked(ik); 1077 info->add_enum_klass_static_field(root_index); 1078 } 1079 1080 void SystemDictionaryShared::check_verification_constraints(InstanceKlass* klass, 1081 TRAPS) { 1082 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only"); 1083 RunTimeClassInfo* record = RunTimeClassInfo::get_for(klass); 1084 1085 int length = record->num_verifier_constraints(); 1086 if (length > 0) { 1087 for (int i = 0; i < length; i++) { 1088 RunTimeClassInfo::RTVerifierConstraint* vc = record->verifier_constraint_at(i); 1089 Symbol* name = vc->name(); 1090 Symbol* from_name = vc->from_name(); 1091 1092 if (from_name == nullptr) { 1093 // This is for old verifier. No need to check, as we can guarantee that all classes checked by 1094 // the old verifier during AOT training phase cannot be replaced in the asembly phase. 1095 precond(CDSConfig::is_dumping_final_static_archive()); 1096 continue; 1097 } 1098 1099 if (log_is_enabled(Trace, aot, verification)) { 1100 ResourceMark rm(THREAD); 1101 log_trace(aot, verification)("check_verification_constraint: %s: %s must be subclass of %s [0x%x]", 1102 klass->external_name(), from_name->as_klass_external_name(), 1103 name->as_klass_external_name(), record->verifier_constraint_flag(i)); 1104 } 1105 1106 bool ok = VerificationType::resolve_and_check_assignability(klass, name, from_name, 1107 record->from_field_is_protected(i), record->from_is_array(i), record->from_is_object(i), CHECK); 1108 if (!ok) { 1109 ResourceMark rm(THREAD); 1110 stringStream ss; 1111 1112 ss.print_cr("Bad type on operand stack"); 1113 ss.print_cr("Exception Details:"); 1114 ss.print_cr(" Location:\n %s", klass->name()->as_C_string()); 1115 ss.print_cr(" Reason:\n Type '%s' is not assignable to '%s'", 1116 from_name->as_quoted_ascii(), name->as_quoted_ascii()); 1117 THROW_MSG(vmSymbols::java_lang_VerifyError(), ss.as_string()); 1118 } 1119 } 1120 } 1121 } 1122 1123 void SystemDictionaryShared::copy_verification_info_from_preimage(InstanceKlass* klass) { 1124 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only"); 1125 DumpTimeClassInfo* dt_info = get_info(klass); 1126 RunTimeClassInfo* rt_info = RunTimeClassInfo::get_for(klass); // from preimage 1127 1128 int length = rt_info->num_verifier_constraints(); 1129 if (length > 0) { 1130 for (int i = 0; i < length; i++) { 1131 RunTimeClassInfo::RTVerifierConstraint* vc = rt_info->verifier_constraint_at(i); 1132 Symbol* name = vc->name(); 1133 Symbol* from_name = vc->from_name(); 1134 1135 dt_info->add_verification_constraint(name, from_name, 1136 rt_info->from_field_is_protected(i), rt_info->from_is_array(i), rt_info->from_is_object(i)); 1137 } 1138 } 1139 } 1140 1141 static oop get_class_loader_by(char type) { 1142 if (type == (char)ClassLoader::BOOT_LOADER) { 1143 return (oop)nullptr; 1144 } else if (type == (char)ClassLoader::PLATFORM_LOADER) { 1145 return SystemDictionary::java_platform_loader(); 1146 } else { 1147 assert (type == (char)ClassLoader::APP_LOADER, "Sanity"); 1148 return SystemDictionary::java_system_loader(); 1149 } 1150 } 1151 1152 // Record class loader constraints that are checked inside 1153 // InstanceKlass::link_class(), so that these can be checked quickly 1154 // at runtime without laying out the vtable/itables. 1155 void SystemDictionaryShared::record_linking_constraint(Symbol* name, InstanceKlass* klass, 1156 Handle loader1, Handle loader2) { 1157 // A linking constraint check is executed when: 1158 // - klass extends or implements type S 1159 // - klass overrides method S.M(...) with X.M 1160 // - If klass defines the method M, X is 1161 // the same as klass. 1162 // - If klass does not define the method M, 1163 // X must be a supertype of klass and X.M is 1164 // a default method defined by X. 1165 // - loader1 = X->class_loader() 1166 // - loader2 = S->class_loader() 1167 // - loader1 != loader2 1168 // - M's parameter(s) include an object type T 1169 // We require that 1170 // - whenever loader1 and loader2 try to 1171 // resolve the type T, they must always resolve to 1172 // the same InstanceKlass. 1173 // NOTE: type T may or may not be currently resolved in 1174 // either of these two loaders. The check itself does not 1175 // try to resolve T. 1176 oop klass_loader = klass->class_loader(); 1177 1178 if (!is_system_class_loader(klass_loader) && 1179 !is_platform_class_loader(klass_loader)) { 1180 // If klass is loaded by system/platform loaders, we can 1181 // guarantee that klass and S must be loaded by the same 1182 // respective loader between dump time and run time, and 1183 // the exact same check on (name, loader1, loader2) will 1184 // be executed. Hence, we can cache this check and execute 1185 // it at runtime without walking the vtable/itables. 1186 // 1187 // This cannot be guaranteed for classes loaded by other 1188 // loaders, so we bail. 1189 return; 1190 } 1191 1192 assert(is_builtin(klass), "must be"); 1193 assert(klass_loader != nullptr, "should not be called for boot loader"); 1194 assert(loader1 != loader2, "must be"); 1195 1196 if (CDSConfig::is_dumping_dynamic_archive() && Thread::current()->is_VM_thread()) { 1197 // We are re-laying out the vtable/itables of the *copy* of 1198 // a class during the final stage of dynamic dumping. The 1199 // linking constraints for this class has already been recorded. 1200 return; 1201 } 1202 assert(!Thread::current()->is_VM_thread(), "must be"); 1203 1204 assert(CDSConfig::is_dumping_archive(), "sanity"); 1205 DumpTimeClassInfo* info = get_info(klass); 1206 info->record_linking_constraint(name, loader1, loader2); 1207 } 1208 1209 // returns true IFF there's no need to re-initialize the i/v-tables for klass for 1210 // the purpose of checking class loader constraints. 1211 bool SystemDictionaryShared::check_linking_constraints(Thread* current, InstanceKlass* klass) { 1212 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only"); 1213 LogTarget(Info, class, loader, constraints) log; 1214 if (klass->defined_by_boot_loader()) { 1215 // No class loader constraint check performed for boot classes. 1216 return true; 1217 } 1218 if (klass->defined_by_platform_loader() || klass->defined_by_app_loader()) { 1219 RunTimeClassInfo* info = RunTimeClassInfo::get_for(klass); 1220 assert(info != nullptr, "Sanity"); 1221 if (info->num_loader_constraints() > 0) { 1222 HandleMark hm(current); 1223 for (int i = 0; i < info->num_loader_constraints(); i++) { 1224 RunTimeClassInfo::RTLoaderConstraint* lc = info->loader_constraint_at(i); 1225 Symbol* name = lc->constraint_name(); 1226 Handle loader1(current, get_class_loader_by(lc->_loader_type1)); 1227 Handle loader2(current, get_class_loader_by(lc->_loader_type2)); 1228 if (log.is_enabled()) { 1229 ResourceMark rm(current); 1230 log.print("[CDS add loader constraint for class %s symbol %s loader[0] %s loader[1] %s", 1231 klass->external_name(), name->as_C_string(), 1232 ClassLoaderData::class_loader_data(loader1())->loader_name_and_id(), 1233 ClassLoaderData::class_loader_data(loader2())->loader_name_and_id()); 1234 } 1235 if (!SystemDictionary::add_loader_constraint(name, klass, loader1, loader2)) { 1236 // Loader constraint violation has been found. The caller 1237 // will re-layout the vtable/itables to produce the correct 1238 // exception. 1239 if (log.is_enabled()) { 1240 log.print(" failed]"); 1241 } 1242 return false; 1243 } 1244 if (log.is_enabled()) { 1245 log.print(" succeeded]"); 1246 } 1247 } 1248 return true; // for all recorded constraints added successfully. 1249 } 1250 } 1251 if (log.is_enabled()) { 1252 ResourceMark rm(current); 1253 log.print("[CDS has not recorded loader constraint for class %s]", klass->external_name()); 1254 } 1255 return false; 1256 } 1257 1258 void SystemDictionaryShared::copy_linking_constraints_from_preimage(InstanceKlass* klass) { 1259 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only"); 1260 JavaThread* current = JavaThread::current(); 1261 if (klass->defined_by_platform_loader() || klass->defined_by_app_loader()) { 1262 RunTimeClassInfo* rt_info = RunTimeClassInfo::get_for(klass); // from preimage 1263 1264 if (rt_info->num_loader_constraints() > 0) { 1265 for (int i = 0; i < rt_info->num_loader_constraints(); i++) { 1266 RunTimeClassInfo::RTLoaderConstraint* lc = rt_info->loader_constraint_at(i); 1267 Symbol* name = lc->constraint_name(); 1268 Handle loader1(current, get_class_loader_by(lc->_loader_type1)); 1269 Handle loader2(current, get_class_loader_by(lc->_loader_type2)); 1270 record_linking_constraint(name, klass, loader1, loader2); 1271 } 1272 } 1273 } 1274 } 1275 1276 unsigned int SystemDictionaryShared::hash_for_shared_dictionary(address ptr) { 1277 if (ArchiveBuilder::is_active() && ArchiveBuilder::current()->is_in_buffer_space(ptr)) { 1278 uintx offset = ArchiveBuilder::current()->any_to_offset(ptr); 1279 unsigned int hash = primitive_hash<uintx>(offset); 1280 DEBUG_ONLY({ 1281 if (MetaspaceObj::in_aot_cache((const MetaspaceObj*)ptr)) { 1282 assert(hash == SystemDictionaryShared::hash_for_shared_dictionary_quick(ptr), "must be"); 1283 } 1284 }); 1285 return hash; 1286 } else { 1287 return SystemDictionaryShared::hash_for_shared_dictionary_quick(ptr); 1288 } 1289 } 1290 1291 class CopySharedClassInfoToArchive : StackObj { 1292 CompactHashtableWriter* _writer; 1293 bool _is_builtin; 1294 ArchiveBuilder *_builder; 1295 public: 1296 CopySharedClassInfoToArchive(CompactHashtableWriter* writer, 1297 bool is_builtin) 1298 : _writer(writer), _is_builtin(is_builtin), _builder(ArchiveBuilder::current()) {} 1299 1300 void do_entry(InstanceKlass* k, DumpTimeClassInfo& info) { 1301 if (!info.is_excluded() && info.is_builtin() == _is_builtin) { 1302 size_t byte_size = info.runtime_info_bytesize(); 1303 RunTimeClassInfo* record; 1304 record = (RunTimeClassInfo*)ArchiveBuilder::ro_region_alloc(byte_size); 1305 record->init(info); 1306 1307 unsigned int hash; 1308 Symbol* name = info._klass->name(); 1309 name = ArchiveBuilder::current()->get_buffered_addr(name); 1310 hash = SystemDictionaryShared::hash_for_shared_dictionary((address)name); 1311 u4 delta = _builder->buffer_to_offset_u4((address)record); 1312 if (_is_builtin && info._klass->is_hidden()) { 1313 // skip 1314 } else { 1315 _writer->add(hash, delta); 1316 } 1317 if (log_is_enabled(Trace, aot, hashtables)) { 1318 ResourceMark rm; 1319 log_trace(aot, hashtables)("%s dictionary: %s", (_is_builtin ? "builtin" : "unregistered"), info._klass->external_name()); 1320 } 1321 1322 // Save this for quick runtime lookup of InstanceKlass* -> RunTimeClassInfo* 1323 InstanceKlass* buffered_klass = ArchiveBuilder::current()->get_buffered_addr(info._klass); 1324 RunTimeClassInfo::set_for(buffered_klass, record); 1325 } 1326 } 1327 }; 1328 1329 void SystemDictionaryShared::write_dictionary(RunTimeSharedDictionary* dictionary, 1330 bool is_builtin) { 1331 CompactHashtableStats stats; 1332 dictionary->reset(); 1333 CompactHashtableWriter writer(_dumptime_table->count_of(is_builtin), &stats); 1334 CopySharedClassInfoToArchive copy(&writer, is_builtin); 1335 assert_lock_strong(DumpTimeTable_lock); 1336 _dumptime_table->iterate_all_live_classes(©); 1337 writer.dump(dictionary, is_builtin ? "builtin dictionary" : "unregistered dictionary"); 1338 } 1339 1340 void SystemDictionaryShared::write_to_archive(bool is_static_archive) { 1341 ArchiveInfo* archive = get_archive(is_static_archive); 1342 1343 write_dictionary(&archive->_builtin_dictionary, true); 1344 write_dictionary(&archive->_unregistered_dictionary, false); 1345 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) { 1346 LambdaProxyClassDictionary::write_dictionary(is_static_archive); 1347 } else { 1348 LambdaProxyClassDictionary::reset_dictionary(is_static_archive); 1349 } 1350 } 1351 1352 void SystemDictionaryShared::serialize_dictionary_headers(SerializeClosure* soc, 1353 bool is_static_archive) { 1354 ArchiveInfo* archive = get_archive(is_static_archive); 1355 1356 archive->_builtin_dictionary.serialize_header(soc); 1357 archive->_unregistered_dictionary.serialize_header(soc); 1358 LambdaProxyClassDictionary::serialize(soc, is_static_archive); 1359 } 1360 1361 void SystemDictionaryShared::serialize_vm_classes(SerializeClosure* soc) { 1362 for (auto id : EnumRange<vmClassID>{}) { 1363 soc->do_ptr(vmClasses::klass_addr_at(id)); 1364 } 1365 } 1366 1367 const RunTimeClassInfo* 1368 SystemDictionaryShared::find_record(RunTimeSharedDictionary* static_dict, RunTimeSharedDictionary* dynamic_dict, Symbol* name) { 1369 if (!CDSConfig::is_using_archive() || !name->in_aot_cache()) { 1370 // The names of all shared classes must also be a shared Symbol. 1371 return nullptr; 1372 } 1373 1374 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(name); 1375 const RunTimeClassInfo* record = nullptr; 1376 if (DynamicArchive::is_mapped()) { 1377 // Use the regenerated holder classes in the dynamic archive as they 1378 // have more methods than those in the base archive. 1379 if (LambdaFormInvokers::may_be_regenerated_class(name)) { 1380 record = dynamic_dict->lookup(name, hash, 0); 1381 if (record != nullptr) { 1382 return record; 1383 } 1384 } 1385 } 1386 1387 if (!AOTMetaspace::in_aot_cache_dynamic_region(name)) { 1388 // The names of all shared classes in the static dict must also be in the 1389 // static archive 1390 record = static_dict->lookup(name, hash, 0); 1391 } 1392 1393 if (record == nullptr && DynamicArchive::is_mapped()) { 1394 record = dynamic_dict->lookup(name, hash, 0); 1395 } 1396 1397 return record; 1398 } 1399 1400 InstanceKlass* SystemDictionaryShared::find_builtin_class(Symbol* name) { 1401 const RunTimeClassInfo* record = find_record(&_static_archive._builtin_dictionary, 1402 &_dynamic_archive._builtin_dictionary, 1403 name); 1404 if (record != nullptr) { 1405 assert(!record->klass()->is_hidden(), "hidden class cannot be looked up by name"); 1406 DEBUG_ONLY(check_klass_after_loading(record->klass());) 1407 // We did not save the classfile data of the generated LambdaForm invoker classes, 1408 // so we cannot support CLFH for such classes. 1409 if (record->klass()->is_aot_generated_class() && JvmtiExport::should_post_class_file_load_hook()) { 1410 return nullptr; 1411 } 1412 return record->klass(); 1413 } else { 1414 return nullptr; 1415 } 1416 } 1417 1418 void SystemDictionaryShared::update_shared_entry(InstanceKlass* k, int id) { 1419 assert(CDSConfig::is_dumping_static_archive(), "class ID is used only for static dump (from classlist)"); 1420 DumpTimeClassInfo* info = get_info(k); 1421 info->_id = id; 1422 } 1423 1424 const char* SystemDictionaryShared::loader_type_for_shared_class(Klass* k) { 1425 assert(k != nullptr, "Sanity"); 1426 assert(k->in_aot_cache(), "Must be"); 1427 assert(k->is_instance_klass(), "Must be"); 1428 InstanceKlass* ik = InstanceKlass::cast(k); 1429 if (ik->defined_by_boot_loader()) { 1430 return "boot_loader"; 1431 } else if (ik->defined_by_platform_loader()) { 1432 return "platform_loader"; 1433 } else if (ik->defined_by_app_loader()) { 1434 return "app_loader"; 1435 } else if (ik->defined_by_other_loaders()) { 1436 return "unregistered_loader"; 1437 } else { 1438 return "unknown loader"; 1439 } 1440 } 1441 1442 void SystemDictionaryShared::get_all_archived_classes(bool is_static_archive, GrowableArray<Klass*>* classes) { 1443 get_archive(is_static_archive)->_builtin_dictionary.iterate([&] (const RunTimeClassInfo* record) { 1444 classes->append(record->klass()); 1445 }); 1446 } 1447 1448 class SharedDictionaryPrinter : StackObj { 1449 outputStream* _st; 1450 int _index; 1451 public: 1452 SharedDictionaryPrinter(outputStream* st) : _st(st), _index(0) {} 1453 1454 void do_value(const RunTimeClassInfo* record) { 1455 ResourceMark rm; 1456 _st->print_cr("%4d: %s %s", _index++, record->klass()->external_name(), 1457 SystemDictionaryShared::loader_type_for_shared_class(record->klass())); 1458 if (record->klass()->array_klasses() != nullptr) { 1459 record->klass()->array_klasses()->cds_print_value_on(_st); 1460 _st->cr(); 1461 } 1462 } 1463 int index() const { return _index; } 1464 }; 1465 1466 void SystemDictionaryShared::ArchiveInfo::print_on(const char* prefix, 1467 outputStream* st, 1468 bool is_static_archive) { 1469 st->print_cr("%sShared Dictionary", prefix); 1470 SharedDictionaryPrinter p(st); 1471 st->print_cr("%sShared Builtin Dictionary", prefix); 1472 _builtin_dictionary.iterate(&p); 1473 st->print_cr("%sShared Unregistered Dictionary", prefix); 1474 _unregistered_dictionary.iterate(&p); 1475 LambdaProxyClassDictionary::print_on(prefix, st, p.index(), is_static_archive); 1476 } 1477 1478 void SystemDictionaryShared::ArchiveInfo::print_table_statistics(const char* prefix, 1479 outputStream* st, 1480 bool is_static_archive) { 1481 st->print_cr("%sArchve Statistics", prefix); 1482 _builtin_dictionary.print_table_statistics(st, "Builtin Shared Dictionary"); 1483 _unregistered_dictionary.print_table_statistics(st, "Unregistered Shared Dictionary"); 1484 LambdaProxyClassDictionary::print_statistics(st, is_static_archive); 1485 } 1486 1487 void SystemDictionaryShared::print_shared_archive(outputStream* st, bool is_static) { 1488 if (CDSConfig::is_using_archive()) { 1489 if (is_static) { 1490 _static_archive.print_on("", st, true); 1491 } else { 1492 if (DynamicArchive::is_mapped()) { 1493 _dynamic_archive.print_on("Dynamic ", st, false); 1494 } 1495 } 1496 } 1497 } 1498 1499 void SystemDictionaryShared::print_on(outputStream* st) { 1500 print_shared_archive(st, true); 1501 print_shared_archive(st, false); 1502 } 1503 1504 void SystemDictionaryShared::print_table_statistics(outputStream* st) { 1505 if (CDSConfig::is_using_archive()) { 1506 _static_archive.print_table_statistics("Static ", st, true); 1507 if (DynamicArchive::is_mapped()) { 1508 _dynamic_archive.print_table_statistics("Dynamic ", st, false); 1509 } 1510 } 1511 } 1512 1513 bool SystemDictionaryShared::is_dumptime_table_empty() { 1514 assert_lock_strong(DumpTimeTable_lock); 1515 _dumptime_table->update_counts(); 1516 if (_dumptime_table->count_of(true) == 0 && _dumptime_table->count_of(false) == 0){ 1517 return true; 1518 } 1519 return false; 1520 } 1521 1522 void SystemDictionaryShared::create_loader_positive_lookup_cache(TRAPS) { 1523 GrowableArray<InstanceKlass*> shared_classes_list; 1524 { 1525 // With static dumping, we have only a single Java thread (see JVM_StartThread) so 1526 // no no other threads should be loading classes. Otherwise, the code below may miss some 1527 // classes that are loaded concurrently. 1528 assert(CDSConfig::is_dumping_static_archive(), "no other threads should be loading classes"); 1529 1530 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag); 1531 _dumptime_table->iterate_all_classes_in_builtin_loaders([&](InstanceKlass* k, DumpTimeClassInfo& info) { 1532 // FIXME -- this may not be correct before SystemDictionaryShared::finish_exclusion_checks() 1533 if (!k->is_hidden() && info.has_checked_exclusion() && !info.is_excluded()) { 1534 shared_classes_list.append(k); 1535 } 1536 } 1537 ); 1538 } 1539 1540 InstanceKlass* ik = vmClasses::Class_klass(); 1541 objArrayOop r = oopFactory::new_objArray(ik, shared_classes_list.length(), CHECK); 1542 objArrayHandle array_h(THREAD, r); 1543 1544 for (int i = 0; i < shared_classes_list.length(); i++) { 1545 oop mirror = shared_classes_list.at(i)->java_mirror(); 1546 Handle mirror_h(THREAD, mirror); 1547 array_h->obj_at_put(i, mirror_h()); 1548 } 1549 1550 TempNewSymbol method = SymbolTable::new_symbol("generatePositiveLookupCache"); 1551 TempNewSymbol signature = SymbolTable::new_symbol("([Ljava/lang/Class;)V"); 1552 1553 JavaCallArguments args(Handle(THREAD, SystemDictionary::java_system_loader())); 1554 args.push_oop(array_h); 1555 JavaValue result(T_VOID); 1556 JavaCalls::call_virtual(&result, 1557 vmClasses::jdk_internal_loader_ClassLoaders_AppClassLoader_klass(), 1558 method, 1559 signature, 1560 &args, 1561 CHECK); 1562 1563 if (HAS_PENDING_EXCEPTION) { 1564 Handle exc_handle(THREAD, PENDING_EXCEPTION); 1565 CLEAR_PENDING_EXCEPTION; 1566 ResourceMark rm(THREAD); 1567 1568 log_warning(cds)("Exception during AppClassLoader::generatePositiveLookupCache() call"); 1569 LogStreamHandle(Debug, cds) log; 1570 if (log.is_enabled()) { 1571 java_lang_Throwable::print_stack_trace(exc_handle, &log); 1572 } 1573 return; 1574 } 1575 }