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