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