1 /*
2 * Copyright (c) 2014, 2026, 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/aotCompressedPointers.hpp"
29 #include "cds/aotLogging.hpp"
30 #include "cds/aotMetaspace.hpp"
31 #include "cds/archiveBuilder.hpp"
32 #include "cds/archiveUtils.hpp"
33 #include "cds/cdsConfig.hpp"
34 #include "cds/cdsProtectionDomain.hpp"
35 #include "cds/classListParser.hpp"
36 #include "cds/classListWriter.hpp"
37 #include "cds/dumpTimeClassInfo.inline.hpp"
38 #include "cds/dynamicArchive.hpp"
39 #include "cds/filemap.hpp"
40 #include "cds/heapShared.hpp"
41 #include "cds/lambdaFormInvokers.inline.hpp"
42 #include "cds/lambdaProxyClassDictionary.hpp"
43 #include "cds/runTimeClassInfo.hpp"
44 #include "cds/unregisteredClasses.hpp"
45 #include "classfile/classFileStream.hpp"
46 #include "classfile/classLoader.hpp"
47 #include "classfile/classLoaderData.inline.hpp"
48 #include "classfile/classLoaderDataGraph.hpp"
49 #include "classfile/dictionary.hpp"
50 #include "classfile/javaClasses.inline.hpp"
51 #include "classfile/symbolTable.hpp"
52 #include "classfile/systemDictionary.hpp"
53 #include "classfile/systemDictionaryShared.hpp"
54 #include "classfile/verificationType.hpp"
55 #include "classfile/vmClasses.hpp"
56 #include "classfile/vmSymbols.hpp"
57 #include "jfr/jfrEvents.hpp"
58 #include "logging/log.hpp"
59 #include "logging/logStream.hpp"
60 #include "memory/allocation.hpp"
61 #include "memory/metadataFactory.hpp"
62 #include "memory/metaspaceClosure.hpp"
63 #include "memory/oopFactory.hpp"
64 #include "memory/resourceArea.hpp"
65 #include "memory/universe.hpp"
66 #include "oops/compressedKlass.inline.hpp"
67 #include "oops/instanceKlass.hpp"
68 #include "oops/klass.inline.hpp"
69 #include "oops/objArrayKlass.hpp"
70 #include "oops/objArrayOop.inline.hpp"
71 #include "oops/oop.inline.hpp"
72 #include "oops/oopHandle.inline.hpp"
73 #include "oops/typeArrayOop.inline.hpp"
74 #include "runtime/arguments.hpp"
75 #include "runtime/handles.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/mutexLocker.hpp"
79 #include "utilities/hashTable.hpp"
80 #include "utilities/stringUtils.hpp"
81
82 SystemDictionaryShared::ArchiveInfo SystemDictionaryShared::_static_archive;
83 SystemDictionaryShared::ArchiveInfo SystemDictionaryShared::_dynamic_archive;
84
85 DumpTimeSharedClassTable* SystemDictionaryShared::_dumptime_table = nullptr;
86
87 // Used by NoClassLoadingMark
88 DEBUG_ONLY(bool SystemDictionaryShared::_class_loading_may_happen = true;)
89
90 #ifdef ASSERT
91 static void check_klass_after_loading(const Klass* k) {
92 #ifdef _LP64
93 if (k != nullptr && UseCompressedClassPointers) {
94 CompressedKlassPointers::check_encodable(k);
95 }
96 #endif
97 }
98 #endif
99
100 InstanceKlass* SystemDictionaryShared::load_shared_class_for_builtin_loader(
101 Symbol* class_name, Handle class_loader, TRAPS) {
102 assert(CDSConfig::is_using_archive(), "must be");
103 InstanceKlass* ik = find_builtin_class(class_name);
104
105 if (ik != nullptr && !ik->shared_loading_failed()) {
106 if ((SystemDictionary::is_system_class_loader(class_loader()) && ik->defined_by_app_loader()) ||
107 (SystemDictionary::is_platform_class_loader(class_loader()) && ik->defined_by_platform_loader())) {
108 SharedClassLoadingMark slm(THREAD, ik);
109 PackageEntry* pkg_entry = CDSProtectionDomain::get_package_entry_from_class(ik, class_loader);
110 Handle protection_domain =
111 CDSProtectionDomain::init_security_info(class_loader, ik, pkg_entry, CHECK_NULL);
112 return load_shared_class(ik, class_loader, protection_domain, nullptr, pkg_entry, THREAD);
113 }
114 }
115 return nullptr;
116 }
117
118 // This function is called for loading only UNREGISTERED classes
119 InstanceKlass* SystemDictionaryShared::lookup_from_stream(Symbol* class_name,
120 Handle class_loader,
121 Handle protection_domain,
122 const ClassFileStream* cfs,
123 TRAPS) {
124 if (!CDSConfig::is_using_archive()) {
125 return nullptr;
126 }
127 if (class_name == nullptr) { // don't do this for hidden classes
128 return nullptr;
129 }
130 if (class_loader.is_null() ||
131 SystemDictionary::is_system_class_loader(class_loader()) ||
132 SystemDictionary::is_platform_class_loader(class_loader())) {
133 // Do nothing for the BUILTIN loaders.
134 return nullptr;
135 }
136
137 const RunTimeClassInfo* record = find_record(&_static_archive._unregistered_dictionary,
138 &_dynamic_archive._unregistered_dictionary,
139 class_name);
140 if (record == nullptr) {
141 return nullptr;
142 }
143
144 int clsfile_size = cfs->length();
145 int clsfile_crc32 = ClassLoader::crc32(0, (const char*)cfs->buffer(), cfs->length());
146
147 if (!record->matches(clsfile_size, clsfile_crc32)) {
148 return nullptr;
149 }
150
151 return acquire_class_for_current_thread(record->klass(), class_loader,
152 protection_domain, cfs,
153 THREAD);
154 }
155
156 InstanceKlass* SystemDictionaryShared::acquire_class_for_current_thread(
157 InstanceKlass *ik,
158 Handle class_loader,
159 Handle protection_domain,
160 const ClassFileStream *cfs,
161 TRAPS) {
162 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
163
164 {
165 MutexLocker mu(THREAD, SharedDictionary_lock);
166 if (ik->class_loader_data() != nullptr) {
167 // ik is already loaded (by this loader or by a different loader)
168 // or ik is being loaded by a different thread (by this loader or by a different loader)
169 return nullptr;
170 }
171
172 // No other thread has acquired this yet, so give it to *this thread*
173 ik->set_class_loader_data(loader_data);
174 }
175
176 // No longer holding SharedDictionary_lock
177 // No need to lock, as <ik> can be held only by a single thread.
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 void SystemDictionaryShared::log_exclusion(InstanceKlass* k, const char* reason, bool is_warning) {
358 ResourceMark rm;
359 if (is_warning) {
360 aot_log_warning(aot)("Skipping %s: %s", k->name()->as_C_string(), reason);
361 } else {
362 aot_log_info(aot)("Skipping %s: %s", k->name()->as_C_string(), reason);
363 }
364 }
365
366 bool SystemDictionaryShared::is_jfr_event_class(InstanceKlass *k) {
367 while (k) {
368 if (k->name()->equals("jdk/internal/event/Event")) {
369 return true;
370 }
371 k = k->super();
372 }
373 return false;
374 }
375
376 bool SystemDictionaryShared::is_early_klass(InstanceKlass* ik) {
377 DumpTimeClassInfo* info = _dumptime_table->get(ik);
378 return (info != nullptr) ? info->is_early_klass() : false;
379 }
380
381 bool SystemDictionaryShared::check_self_exclusion(InstanceKlass* k) {
382 bool log_warning = false;
383 const char* error = check_self_exclusion_helper(k, log_warning);
384 if (error != nullptr) {
385 log_exclusion(k, error, log_warning);
386 return true; // Should be excluded
387 } else {
388 return false; // Should not be excluded
389 }
390 }
391
392 const char* SystemDictionaryShared::check_self_exclusion_helper(InstanceKlass* k, bool& log_warning) {
393 assert_lock_strong(DumpTimeTable_lock);
394 if (CDSConfig::is_dumping_final_static_archive() && k->defined_by_other_loaders()
395 && k->in_aot_cache()) {
396 return nullptr; // Do not exclude: unregistered classes are passed from preimage to final image.
397 }
398
399 if (k->is_in_error_state()) {
400 log_warning = true;
401 return "In error state";
402 }
403 if (k->is_scratch_class()) {
404 return "A scratch class";
405 }
406 if (!k->is_loaded()) {
407 return "Not in loaded state";
408 }
409 if (has_been_redefined(k)) {
410 return "Has been redefined";
411 }
412 if (!k->is_hidden() && k->shared_classpath_index() < 0 && is_builtin(k)) {
413 if (k->name()->starts_with("java/lang/invoke/BoundMethodHandle$Species_")) {
414 // This class is dynamically generated by the JDK
415 if (CDSConfig::is_dumping_method_handles()) {
416 k->set_shared_classpath_index(0);
417 } else {
418 return "dynamically generated";
419 }
420 } else {
421 // These are classes loaded from unsupported locations (such as those loaded by JVMTI native
422 // agent during dump time).
423 return "Unsupported location";
424 }
425 }
426 if (k->signers() != nullptr) {
427 // We cannot include signed classes in the archive because the certificates
428 // used during dump time may be different than those used during
429 // runtime (due to expiration, etc).
430 return "Signed JAR";
431 }
432 if (is_jfr_event_class(k)) {
433 // We cannot include JFR event classes because they need runtime-specific
434 // instrumentation in order to work with -XX:FlightRecorderOptions:retransform=false.
435 // There are only a small number of these classes, so it's not worthwhile to
436 // support them and make CDS more complicated.
437 return "JFR event class";
438 }
439
440 if (!k->is_linked()) {
441 if (has_class_failed_verification(k)) {
442 log_warning = true;
443 return "Failed verification";
444 } else if (CDSConfig::is_dumping_aot_linked_classes()) {
445 // Most loaded classes should have been speculatively linked by AOTMetaspace::link_class_for_cds().
446 // Old classes may not be linked if CDSConfig::is_preserving_verification_constraints()==false.
447 // An unlinked class may fail to verify in AOTLinkedClassBulkLoader::init_required_classes_for_loader(),
448 // causing the JVM to fail at bootstrap.
449 return "Unlinked class not supported by AOTClassLinking";
450 } else if (CDSConfig::is_dumping_preimage_static_archive()) {
451 // When dumping the final static archive, we will unconditionally load and link all
452 // classes from the preimage. We don't want to get a VerifyError when linking this class.
453 return "Unlinked class not supported by AOTConfiguration";
454 }
455 } else {
456 if (!k->can_be_verified_at_dumptime()) {
457 // We have an old class that has been linked (e.g., it's been executed during
458 // dump time). This class has been verified using the old verifier, which
459 // doesn't save the verification constraints, so check_verification_constraints()
460 // won't work at runtime.
461 // As a result, we cannot store this class. It must be loaded and fully verified
462 // at runtime.
463 return "Old class has been linked";
464 }
465 }
466
467 if (UnregisteredClasses::check_for_exclusion(k)) {
468 return "used only when dumping CDS archive";
469 }
470
471 return nullptr;
472 }
473
474 // Returns true if DumpTimeClassInfo::is_excluded() is true for at least one of k's exclusion dependencies.
475 bool SystemDictionaryShared::check_dependencies_exclusion(InstanceKlass* k, DumpTimeClassInfo* info) {
476 InstanceKlass* super = k->java_super();
477 if (super != nullptr && is_dependency_excluded(k, super, "super")) {
478 return true;
479 }
480
481 Array<InstanceKlass*>* interfaces = k->local_interfaces();
482 int len = interfaces->length();
483 for (int i = 0; i < len; i++) {
484 InstanceKlass* intf = interfaces->at(i);
485 if (is_dependency_excluded(k, intf, "interface")) {
486 return true;
487 }
488 }
489
490 InstanceKlass* nest_host = k->nest_host_or_null();
491 if (nest_host != nullptr && nest_host != k && is_dependency_excluded(k, nest_host, "nest host class")) {
492 return true;
493 }
494
495 if (CDSConfig::is_preserving_verification_constraints()) {
496 bool excluded = false;
497
498 iterate_verification_constraint_names(k, info, [&] (Symbol* constraint_class_name) {
499 if (check_verification_constraint_exclusion(k, constraint_class_name)) {
500 // If one of the verification constraint class has been excluded, the assignability checks
501 // by the verifier may no longer be valid in the production run. For safety, exclude this class.
502 excluded = true;
503 return false; // terminate iteration; k will be excluded
504 } else {
505 return true; // keep iterating
506 }
507 });
508
509 if (excluded) {
510 // At least one verification constraint class has been excluded
511 return true;
512 }
513 }
514
515 return false;
516 }
517
518 bool SystemDictionaryShared::is_dependency_excluded(InstanceKlass* k, InstanceKlass* dependency, const char* type) {
519 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(dependency)) {
520 return false;
521 }
522 DumpTimeClassInfo* dependency_info = get_info_locked(dependency);
523 if (dependency_info->is_excluded()) {
524 ResourceMark rm;
525 aot_log_info(aot)("Skipping %s: %s %s is excluded", k->name()->as_C_string(), type, dependency->name()->as_C_string());
526 return true;
527 }
528 return false;
529 }
530
531 bool SystemDictionaryShared::check_verification_constraint_exclusion(InstanceKlass* k, Symbol* constraint_class_name) {
532 Klass* constraint_bottom_class = find_verification_constraint_bottom_class(k, constraint_class_name);
533 if (constraint_bottom_class == nullptr) {
534 // We don't have a bottom class (constraint_class_name is a type array), or constraint_class_name
535 // has not been loaded. The latter case happens when the new verifier was checking
536 // if constraint_class_name is assignable to an interface, and found the answer without resolving
537 // constraint_class_name.
538 //
539 // Since this class is not even loaded, it surely cannot be excluded.
540 return false;
541 } else if (constraint_bottom_class->is_instance_klass()) {
542 if (is_dependency_excluded(k, InstanceKlass::cast(constraint_bottom_class), "verification constraint")) {
543 return true;
544 }
545 } else {
546 assert(constraint_bottom_class->is_typeArray_klass(), "must be");
547 }
548
549 return false;
550 }
551
552 Klass* SystemDictionaryShared::find_verification_constraint_bottom_class(InstanceKlass* k, Symbol* constraint_class_name) {
553 Thread* current = Thread::current();
554 Handle loader(current, k->class_loader());
555 Klass* constraint_class = SystemDictionary::find_instance_or_array_klass(current, constraint_class_name, loader);
556 if (constraint_class == nullptr) {
557 return nullptr;
558 }
559
560 if (constraint_class->is_objArray_klass()) {
561 constraint_class = ObjArrayKlass::cast(constraint_class)->bottom_klass();
562 }
563
564 precond(constraint_class->is_typeArray_klass() || constraint_class->is_instance_klass());
565 return constraint_class;
566 }
567
568 bool SystemDictionaryShared::is_builtin_loader(ClassLoaderData* loader_data) {
569 oop class_loader = loader_data->class_loader();
570 return (class_loader == nullptr ||
571 SystemDictionary::is_system_class_loader(class_loader) ||
572 SystemDictionary::is_platform_class_loader(class_loader));
573 }
574
575 bool SystemDictionaryShared::has_platform_or_app_classes() {
576 if (FileMapInfo::current_info()->has_platform_or_app_classes()) {
577 return true;
578 }
579 if (DynamicArchive::is_mapped() &&
580 FileMapInfo::dynamic_info()->has_platform_or_app_classes()) {
581 return true;
582 }
583 return false;
584 }
585
586 // The following stack shows how this code is reached:
587 //
588 // [0] SystemDictionaryShared::find_or_load_shared_class()
589 // [1] JVM_FindLoadedClass
590 // [2] java.lang.ClassLoader.findLoadedClass0()
591 // [3] java.lang.ClassLoader.findLoadedClass()
592 // [4] jdk.internal.loader.BuiltinClassLoader.loadClassOrNull()
593 // [5] jdk.internal.loader.BuiltinClassLoader.loadClass()
594 // [6] jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(), or
595 // jdk.internal.loader.ClassLoaders$PlatformClassLoader.loadClass()
596 //
597 // AppCDS supports fast class loading for these 2 built-in class loaders:
598 // jdk.internal.loader.ClassLoaders$PlatformClassLoader
599 // jdk.internal.loader.ClassLoaders$AppClassLoader
600 // with the following assumptions (based on the JDK core library source code):
601 //
602 // [a] these two loaders use the BuiltinClassLoader.loadClassOrNull() to
603 // load the named class.
604 // [b] BuiltinClassLoader.loadClassOrNull() first calls findLoadedClass(name).
605 // [c] At this point, if we can find the named class inside the
606 // shared_dictionary, we can perform further checks (see
607 // SystemDictionary::is_shared_class_visible) to ensure that this class
608 // was loaded by the same class loader during dump time.
609 //
610 // Given these assumptions, we intercept the findLoadedClass() call to invoke
611 // SystemDictionaryShared::find_or_load_shared_class() to load the shared class from
612 // the archive for the 2 built-in class loaders. This way,
613 // we can improve start-up because we avoid decoding the classfile,
614 // and avoid delegating to the parent loader.
615 //
616 // NOTE: there's a lot of assumption about the Java code. If any of that change, this
617 // needs to be redesigned.
618
619 InstanceKlass* SystemDictionaryShared::find_or_load_shared_class(
620 Symbol* name, Handle class_loader, TRAPS) {
621 InstanceKlass* k = nullptr;
622 if (CDSConfig::is_using_archive()) {
623 if (!has_platform_or_app_classes()) {
624 return nullptr;
625 }
626
627 if (SystemDictionary::is_system_class_loader(class_loader()) ||
628 SystemDictionary::is_platform_class_loader(class_loader())) {
629 ClassLoaderData *loader_data = register_loader(class_loader);
630 Dictionary* dictionary = loader_data->dictionary();
631
632 // Note: currently, find_or_load_shared_class is called only from
633 // JVM_FindLoadedClass and used for PlatformClassLoader and AppClassLoader,
634 // which are parallel-capable loaders, so a lock here is NOT taken.
635 assert(get_loader_lock_or_null(class_loader) == nullptr, "ObjectLocker not required");
636 {
637 MutexLocker mu(THREAD, SystemDictionary_lock);
638 InstanceKlass* check = dictionary->find_class(THREAD, name);
639 if (check != nullptr) {
640 return check;
641 }
642 }
643
644 k = load_shared_class_for_builtin_loader(name, class_loader, THREAD);
645 if (k != nullptr) {
646 SharedClassLoadingMark slm(THREAD, k);
647 k = find_or_define_instance_class(name, class_loader, k, CHECK_NULL);
648 }
649 }
650 }
651
652 DEBUG_ONLY(check_klass_after_loading(k);)
653
654 return k;
655 }
656
657 class UnregisteredClassesTable : public HashTable<
658 Symbol*, InstanceKlass*,
659 15889, // prime number
660 AnyObj::C_HEAP> {};
661
662 static UnregisteredClassesTable* _unregistered_classes_table = nullptr;
663
664 // true == class was successfully added; false == a duplicated class (with the same name) already exists.
665 bool SystemDictionaryShared::add_unregistered_class(Thread* current, InstanceKlass* klass) {
666 // We don't allow duplicated unregistered classes with the same name.
667 // We only archive the first class with that name that succeeds putting
668 // itself into the table.
669 assert(CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled(), "sanity");
670 MutexLocker ml(current, UnregisteredClassesTable_lock, Mutex::_no_safepoint_check_flag);
671 Symbol* name = klass->name();
672 if (_unregistered_classes_table == nullptr) {
673 _unregistered_classes_table = new (mtClass)UnregisteredClassesTable();
674 }
675 bool created;
676 InstanceKlass** v = _unregistered_classes_table->put_if_absent(name, klass, &created);
677 if (created) {
678 name->increment_refcount();
679 }
680 return (klass == *v);
681 }
682
683 InstanceKlass* SystemDictionaryShared::get_unregistered_class(Symbol* name) {
684 assert(CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled(), "sanity");
685 if (_unregistered_classes_table == nullptr) {
686 return nullptr;
687 }
688 InstanceKlass** k = _unregistered_classes_table->get(name);
689 return k != nullptr ? *k : nullptr;
690 }
691
692 void SystemDictionaryShared::copy_unregistered_class_size_and_crc32(InstanceKlass* klass) {
693 precond(CDSConfig::is_dumping_final_static_archive());
694 precond(klass->in_aot_cache());
695
696 // A shared class must have a RunTimeClassInfo record
697 const RunTimeClassInfo* record = find_record(&_static_archive._unregistered_dictionary,
698 nullptr, klass->name());
699 precond(record != nullptr);
700 precond(record->klass() == klass);
701
702 DumpTimeClassInfo* info = get_info(klass);
703 info->_clsfile_size = record->crc()->_clsfile_size;
704 info->_clsfile_crc32 = record->crc()->_clsfile_crc32;
705 }
706
707 void SystemDictionaryShared::set_shared_class_misc_info(InstanceKlass* k, ClassFileStream* cfs) {
708 assert(CDSConfig::is_dumping_archive(), "sanity");
709 assert(!is_builtin(k), "must be unregistered class");
710 DumpTimeClassInfo* info = get_info(k);
711 info->_clsfile_size = cfs->length();
712 info->_clsfile_crc32 = ClassLoader::crc32(0, (const char*)cfs->buffer(), cfs->length());
713 }
714
715 void SystemDictionaryShared::initialize() {
716 if (CDSConfig::is_dumping_archive()) {
717 _dumptime_table = new (mtClass) DumpTimeSharedClassTable;
718 LambdaProxyClassDictionary::dumptime_init();
719 if (CDSConfig::is_dumping_heap()) {
720 HeapShared::init_dumping();
721 }
722 }
723 }
724
725 void SystemDictionaryShared::init_dumptime_info(InstanceKlass* k) {
726 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
727 assert(SystemDictionaryShared::class_loading_may_happen(), "sanity");
728 DumpTimeClassInfo* info = _dumptime_table->allocate_info(k);
729 if (AOTClassFilter::is_aot_tooling_class(k)) {
730 info->set_is_aot_tooling_class();
731 }
732 }
733
734 void SystemDictionaryShared::remove_dumptime_info(InstanceKlass* k) {
735 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
736 _dumptime_table->remove(k);
737 }
738
739 void SystemDictionaryShared::handle_class_unloading(InstanceKlass* klass) {
740 if (CDSConfig::is_dumping_archive()) {
741 remove_dumptime_info(klass);
742 }
743
744 if (CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled()) {
745 MutexLocker ml(Thread::current(), UnregisteredClassesTable_lock, Mutex::_no_safepoint_check_flag);
746 if (_unregistered_classes_table != nullptr) {
747 // Remove the class from _unregistered_classes_table: keep the entry but
748 // set it to null. This ensure no classes with the same name can be
749 // added again.
750 InstanceKlass** v = _unregistered_classes_table->get(klass->name());
751 if (v != nullptr) {
752 *v = nullptr;
753 }
754 }
755 } else {
756 assert(_unregistered_classes_table == nullptr, "must not be used");
757 }
758
759 if (ClassListWriter::is_enabled()) {
760 ClassListWriter cw;
761 cw.handle_class_unloading((const InstanceKlass*)klass);
762 }
763 }
764
765 void SystemDictionaryShared::init_dumptime_info_from_preimage(InstanceKlass* k) {
766 init_dumptime_info(k);
767 copy_verification_info_from_preimage(k);
768 copy_linking_constraints_from_preimage(k);
769
770 if (SystemDictionary::is_platform_class_loader(k->class_loader())) {
771 AOTClassLocationConfig::dumptime_set_has_platform_classes();
772 } else if (SystemDictionary::is_system_class_loader(k->class_loader())) {
773 AOTClassLocationConfig::dumptime_set_has_app_classes();
774 }
775 }
776
777 // Check if a class or any of its supertypes has been redefined.
778 bool SystemDictionaryShared::has_been_redefined(InstanceKlass* k) {
779 if (k->has_been_redefined()) {
780 return true;
781 }
782 if (k->super() != nullptr && has_been_redefined(k->super())) {
783 return true;
784 }
785 Array<InstanceKlass*>* interfaces = k->local_interfaces();
786 int len = interfaces->length();
787 for (int i = 0; i < len; i++) {
788 if (has_been_redefined(interfaces->at(i))) {
789 return true;
790 }
791 }
792 return false;
793 }
794
795 // k is a class before relocating by ArchiveBuilder
796 void SystemDictionaryShared::validate_before_archiving(InstanceKlass* k) {
797 ResourceMark rm;
798 const char* name = k->name()->as_C_string();
799 DumpTimeClassInfo* info = _dumptime_table->get(k);
800 assert(!class_loading_may_happen(), "class loading must be disabled");
801 guarantee(info != nullptr, "Class %s must be entered into _dumptime_table", name);
802 guarantee(!info->is_excluded(), "Should not attempt to archive excluded class %s", name);
803 if (is_builtin(k)) {
804 if (k->is_hidden()) {
805 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
806 assert(LambdaProxyClassDictionary::is_registered_lambda_proxy_class(k), "unexpected hidden class %s", name);
807 }
808 }
809 guarantee(!k->defined_by_other_loaders(),
810 "Class loader type must be set for BUILTIN class %s", name);
811
812 } else {
813 guarantee(k->defined_by_other_loaders(),
814 "Class loader type must not be set for UNREGISTERED class %s", name);
815 }
816 }
817
818 class UnregisteredClassesDuplicationChecker : StackObj {
819 GrowableArray<InstanceKlass*> _list;
820 Thread* _thread;
821 public:
822 UnregisteredClassesDuplicationChecker() : _thread(Thread::current()) {}
823
824 void do_entry(InstanceKlass* k, DumpTimeClassInfo& info) {
825 if (!SystemDictionaryShared::is_builtin(k)) {
826 _list.append(k);
827 }
828 }
829
830 static int compare_by_loader(InstanceKlass** a, InstanceKlass** b) {
831 ClassLoaderData* loader_a = a[0]->class_loader_data();
832 ClassLoaderData* loader_b = b[0]->class_loader_data();
833
834 if (loader_a != loader_b) {
835 return primitive_compare(loader_a, loader_b);
836 } else {
837 return primitive_compare(a[0], b[0]);
838 }
839 }
840
841 void mark_duplicated_classes() {
842 // Two loaders may load two identical or similar hierarchies of classes. If we
843 // check for duplication in random order, we may end up excluding important base classes
844 // in both hierarchies, causing most of the classes to be excluded.
845 // We sort the classes by their loaders. This way we're likely to archive
846 // all classes in the one of the two hierarchies.
847 _list.sort(compare_by_loader);
848 for (int i = 0; i < _list.length(); i++) {
849 InstanceKlass* k = _list.at(i);
850 bool i_am_first = SystemDictionaryShared::add_unregistered_class(_thread, k);
851 if (!i_am_first) {
852 SystemDictionaryShared::log_exclusion(k, "Duplicated unregistered class");
853 SystemDictionaryShared::set_excluded_locked(k);
854 }
855 }
856 }
857 };
858
859 void SystemDictionaryShared::link_all_exclusion_check_candidates(InstanceKlass* ik) {
860 bool need_to_link = false;
861 {
862 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
863 ExclusionCheckCandidates candidates(ik);
864
865 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) {
866 if (!k->is_linked()) {
867 need_to_link = true;
868 }
869 });
870 }
871 if (need_to_link) {
872 JavaThread* THREAD = JavaThread::current();
873 if (log_is_enabled(Info, aot, link)) {
874 ResourceMark rm(THREAD);
875 log_info(aot, link)("Link all loaded classes for %s", ik->external_name());
876 }
877 AOTMetaspace::link_all_loaded_classes(THREAD);
878 }
879 }
880
881 // Returns true if the class should be excluded. This can be called by
882 // AOTConstantPoolResolver before or after we enter the CDS safepoint.
883 // When called before the safepoint, we need to link the class so that
884 // it can be checked by should_be_excluded_impl().
885 bool SystemDictionaryShared::should_be_excluded(Klass* k) {
886 assert(CDSConfig::is_dumping_archive(), "sanity");
887 assert(CDSConfig::current_thread_is_vm_or_dumper(), "sanity");
888
889 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(k)) {
890 // We have reached a super type that's already in the base archive. Treat it
891 // as "not excluded".
892 return false;
893 }
894
895 if (k->is_objArray_klass()) {
896 return should_be_excluded(ObjArrayKlass::cast(k)->bottom_klass());
897 } else if (!k->is_instance_klass()) {
898 assert(k->is_typeArray_klass(), "must be");
899 return false;
900 } else {
901 InstanceKlass* ik = InstanceKlass::cast(k);
902
903 if (!SafepointSynchronize::is_at_safepoint()) {
904 {
905 // fast path
906 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
907 DumpTimeClassInfo* p = get_info_locked(ik);
908 if (p->has_checked_exclusion()) {
909 return p->is_excluded();
910 }
911 }
912
913 link_all_exclusion_check_candidates(ik);
914
915 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
916 DumpTimeClassInfo* p = get_info_locked(ik);
917 return should_be_excluded_impl(ik, p);
918 } else {
919 // When called within the CDS safepoint, the correctness of this function
920 // relies on the call to AOTMetaspace::link_all_loaded_classes()
921 // that happened right before we enter the CDS safepoint.
922 //
923 // Do not call this function in other types of safepoints. For example, if this
924 // is called in a GC safepoint, a klass may be improperly excluded because some
925 // of its verification constraints have not yet been linked.
926 assert(CDSConfig::is_at_aot_safepoint(), "Do not call this function in any other safepoint");
927
928 // No need to check for is_linked() as all eligible classes should have
929 // already been linked in AOTMetaspace::link_class_for_cds().
930 // Don't take DumpTimeTable_lock as we are in safepoint.
931 DumpTimeClassInfo* p = _dumptime_table->get(ik);
932 if (p->is_excluded()) {
933 return true;
934 }
935 return should_be_excluded_impl(ik, p);
936 }
937 }
938 }
939
940 void SystemDictionaryShared::finish_exclusion_checks() {
941 assert_at_safepoint();
942 if (CDSConfig::is_dumping_dynamic_archive() || CDSConfig::is_dumping_preimage_static_archive()) {
943 // Do this first -- if a base class is excluded due to duplication,
944 // all of its subclasses will also be excluded.
945 ResourceMark rm;
946 UnregisteredClassesDuplicationChecker dup_checker;
947 _dumptime_table->iterate_all_live_classes(&dup_checker);
948 dup_checker.mark_duplicated_classes();
949 }
950
951 _dumptime_table->iterate_all_live_classes([&] (InstanceKlass* k, DumpTimeClassInfo& info) {
952 SystemDictionaryShared::should_be_excluded_impl(k, &info);
953 });
954
955 _dumptime_table->update_counts();
956 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
957 LambdaProxyClassDictionary::cleanup_dumptime_table();
958 }
959 }
960
961 bool SystemDictionaryShared::is_excluded_class(InstanceKlass* k) {
962 assert(!class_loading_may_happen(), "class loading must be disabled");
963 assert_lock_strong(DumpTimeTable_lock);
964 assert(CDSConfig::is_dumping_archive(), "sanity");
965 DumpTimeClassInfo* p = get_info_locked(k);
966 return p->is_excluded();
967 }
968
969 void SystemDictionaryShared::set_excluded_locked(InstanceKlass* k) {
970 assert_lock_strong(DumpTimeTable_lock);
971 assert(CDSConfig::is_dumping_archive(), "sanity");
972 DumpTimeClassInfo* info = get_info_locked(k);
973 info->set_excluded();
974 }
975
976 void SystemDictionaryShared::set_excluded(InstanceKlass* k) {
977 assert(CDSConfig::is_dumping_archive(), "sanity");
978 DumpTimeClassInfo* info = get_info(k);
979 info->set_excluded();
980 }
981
982 void SystemDictionaryShared::set_class_has_failed_verification(InstanceKlass* ik) {
983 assert(CDSConfig::is_dumping_archive(), "sanity");
984 DumpTimeClassInfo* p = get_info(ik);
985 p->set_failed_verification();
986 }
987
988 bool SystemDictionaryShared::has_class_failed_verification(InstanceKlass* ik) {
989 assert(CDSConfig::is_dumping_archive(), "sanity");
990 DumpTimeClassInfo* p = _dumptime_table->get(ik);
991 return (p == nullptr) ? false : p->failed_verification();
992 }
993
994 void SystemDictionaryShared::set_from_class_file_load_hook(InstanceKlass* ik) {
995 log_exclusion(ik, "From ClassFileLoadHook");
996 set_excluded(ik);
997 }
998
999 void SystemDictionaryShared::dumptime_classes_do(MetaspaceClosure* it) {
1000 assert_lock_strong(DumpTimeTable_lock);
1001
1002 auto do_klass = [&] (InstanceKlass* k, DumpTimeClassInfo& info) {
1003 if (CDSConfig::is_dumping_final_static_archive() && !k->is_loaded()) {
1004 assert(k->defined_by_other_loaders(), "must be");
1005 info.metaspace_pointers_do(it);
1006 } else if (k->is_loader_alive() && !info.is_excluded()) {
1007 info.metaspace_pointers_do(it);
1008 }
1009 };
1010 _dumptime_table->iterate_all_live_classes(do_klass);
1011
1012 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
1013 LambdaProxyClassDictionary::dumptime_classes_do(it);
1014 }
1015 }
1016
1017 // Called from VerificationType::is_reference_assignable_from() before performing the assignability check of
1018 // T1 must be assignable from T2
1019 // Where:
1020 // L is the class loader of <k>
1021 // T1 is the type resolved by L using the name <name>
1022 // T2 is the type resolved by L using the name <from_name>
1023 //
1024 // The meaning of (*skip_assignability_check):
1025 // true: is_reference_assignable_from() should SKIP the assignability check
1026 // false: is_reference_assignable_from() should COMPLETE the assignability check
1027 void SystemDictionaryShared::add_verification_constraint(InstanceKlass* k, Symbol* name,
1028 Symbol* from_name, bool from_field_is_protected, bool from_is_array, bool from_is_object,
1029 bool* skip_assignability_check) {
1030 assert(CDSConfig::is_dumping_archive(), "sanity");
1031 DumpTimeClassInfo* info = get_info(k);
1032 info->add_verification_constraint(name, from_name, from_field_is_protected,
1033 from_is_array, from_is_object);
1034
1035 if (CDSConfig::is_dumping_classic_static_archive() && !is_builtin(k)) {
1036 // This applies ONLY to the "classic" CDS static dump, which reads the list of
1037 // unregistered classes (those intended for custom class loaders) from the classlist
1038 // and loads them using jdk.internal.misc.CDS$UnregisteredClassLoader.
1039 //
1040 // When the classlist contains an unregistered class k, the supertypes of k are also
1041 // recorded in the classlist. However, the classlist does not contain information about
1042 // any class X that's not a supertype of k but is needed in the verification of k.
1043 // As a result, CDS$UnregisteredClassLoader will not know how to resolve X.
1044 //
1045 // Therefore, we tell the verifier to refrain from resolving X. Instead, X is recorded
1046 // (symbolically) in the verification constraints of k. In the production run,
1047 // when k is loaded, we will go through its verification constraints and resolve X to complete
1048 // the is_reference_assignable_from() checks.
1049 *skip_assignability_check = true;
1050 } else {
1051 // In all other cases, we are using an *actual* class loader to load k, so it should be able
1052 // to resolve any types that are needed for the verification of k.
1053 *skip_assignability_check = false;
1054 }
1055 }
1056
1057 // When the old verifier is verifying the class <ik> at dump time, it tries to resolve a
1058 // class with the given <name>. For the verification result to be valid at run time, we must
1059 // ensure that <name> resolves to the exact same Klass as in dump time.
1060 void SystemDictionaryShared::add_old_verification_constraint(Thread* current, InstanceKlass* ik, Symbol* name) {
1061 precond(CDSConfig::is_preserving_verification_constraints());
1062 DumpTimeClassInfo* info = get_info(ik);
1063 info->add_verification_constraint(name);
1064 }
1065
1066 void SystemDictionaryShared::add_enum_klass_static_field(InstanceKlass* ik, int root_index) {
1067 assert(CDSConfig::is_dumping_heap(), "sanity");
1068 DumpTimeClassInfo* info = get_info_locked(ik);
1069 info->add_enum_klass_static_field(root_index);
1070 }
1071
1072 void SystemDictionaryShared::check_verification_constraints(InstanceKlass* klass,
1073 TRAPS) {
1074 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1075 RunTimeClassInfo* record = RunTimeClassInfo::get_for(klass);
1076
1077 int length = record->num_verifier_constraints();
1078 if (length > 0) {
1079 for (int i = 0; i < length; i++) {
1080 RunTimeClassInfo::RTVerifierConstraint* vc = record->verifier_constraint_at(i);
1081 Symbol* name = vc->name();
1082 Symbol* from_name = vc->from_name();
1083
1084 if (from_name == nullptr) {
1085 // This is for old verifier. No need to check, as we can guarantee that all classes checked by
1086 // the old verifier during AOT training phase cannot be replaced in the asembly phase.
1087 precond(CDSConfig::is_dumping_final_static_archive());
1088 continue;
1089 }
1090
1091 if (log_is_enabled(Trace, aot, verification)) {
1092 ResourceMark rm(THREAD);
1093 log_trace(aot, verification)("check_verification_constraint: %s: %s must be subclass of %s [0x%x]",
1094 klass->external_name(), from_name->as_klass_external_name(),
1095 name->as_klass_external_name(), record->verifier_constraint_flag(i));
1096 }
1097
1098 bool ok = VerificationType::resolve_and_check_assignability(klass, name, from_name,
1099 record->from_field_is_protected(i), record->from_is_array(i), record->from_is_object(i), CHECK);
1100 if (!ok) {
1101 ResourceMark rm(THREAD);
1102 stringStream ss;
1103
1104 ss.print_cr("Bad type on operand stack");
1105 ss.print_cr("Exception Details:");
1106 ss.print_cr(" Location:\n %s", klass->name()->as_C_string());
1107 ss.print_cr(" Reason:\n Type '%s' is not assignable to '%s'",
1108 from_name->as_quoted_ascii(), name->as_quoted_ascii());
1109 THROW_MSG(vmSymbols::java_lang_VerifyError(), ss.as_string());
1110 }
1111 }
1112 }
1113 }
1114
1115 void SystemDictionaryShared::copy_verification_info_from_preimage(InstanceKlass* klass) {
1116 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1117 DumpTimeClassInfo* dt_info = get_info(klass);
1118 RunTimeClassInfo* rt_info = RunTimeClassInfo::get_for(klass); // from preimage
1119
1120 int length = rt_info->num_verifier_constraints();
1121 if (length > 0) {
1122 for (int i = 0; i < length; i++) {
1123 RunTimeClassInfo::RTVerifierConstraint* vc = rt_info->verifier_constraint_at(i);
1124 Symbol* name = vc->name();
1125 Symbol* from_name = vc->from_name();
1126
1127 dt_info->add_verification_constraint(name, from_name,
1128 rt_info->from_field_is_protected(i), rt_info->from_is_array(i), rt_info->from_is_object(i));
1129 }
1130 }
1131 }
1132
1133 static oop get_class_loader_by(char type) {
1134 if (type == (char)ClassLoader::BOOT_LOADER) {
1135 return (oop)nullptr;
1136 } else if (type == (char)ClassLoader::PLATFORM_LOADER) {
1137 return SystemDictionary::java_platform_loader();
1138 } else {
1139 assert (type == (char)ClassLoader::APP_LOADER, "Sanity");
1140 return SystemDictionary::java_system_loader();
1141 }
1142 }
1143
1144 // Record class loader constraints that are checked inside
1145 // InstanceKlass::link_class(), so that these can be checked quickly
1146 // at runtime without laying out the vtable/itables.
1147 void SystemDictionaryShared::record_linking_constraint(Symbol* name, InstanceKlass* klass,
1148 Handle loader1, Handle loader2) {
1149 // A linking constraint check is executed when:
1150 // - klass extends or implements type S
1151 // - klass overrides method S.M(...) with X.M
1152 // - If klass defines the method M, X is
1153 // the same as klass.
1154 // - If klass does not define the method M,
1155 // X must be a supertype of klass and X.M is
1156 // a default method defined by X.
1157 // - loader1 = X->class_loader()
1158 // - loader2 = S->class_loader()
1159 // - loader1 != loader2
1160 // - M's parameter(s) include an object type T
1161 // We require that
1162 // - whenever loader1 and loader2 try to
1163 // resolve the type T, they must always resolve to
1164 // the same InstanceKlass.
1165 // NOTE: type T may or may not be currently resolved in
1166 // either of these two loaders. The check itself does not
1167 // try to resolve T.
1168 oop klass_loader = klass->class_loader();
1169
1170 if (!is_system_class_loader(klass_loader) &&
1171 !is_platform_class_loader(klass_loader)) {
1172 // If klass is loaded by system/platform loaders, we can
1173 // guarantee that klass and S must be loaded by the same
1174 // respective loader between dump time and run time, and
1175 // the exact same check on (name, loader1, loader2) will
1176 // be executed. Hence, we can cache this check and execute
1177 // it at runtime without walking the vtable/itables.
1178 //
1179 // This cannot be guaranteed for classes loaded by other
1180 // loaders, so we bail.
1181 return;
1182 }
1183
1184 assert(is_builtin(klass), "must be");
1185 assert(klass_loader != nullptr, "should not be called for boot loader");
1186 assert(loader1 != loader2, "must be");
1187
1188 if (CDSConfig::is_dumping_dynamic_archive() && Thread::current()->is_VM_thread()) {
1189 // We are re-laying out the vtable/itables of the *copy* of
1190 // a class during the final stage of dynamic dumping. The
1191 // linking constraints for this class has already been recorded.
1192 return;
1193 }
1194 assert(!Thread::current()->is_VM_thread(), "must be");
1195
1196 assert(CDSConfig::is_dumping_archive(), "sanity");
1197 DumpTimeClassInfo* info = get_info(klass);
1198 info->record_linking_constraint(name, loader1, loader2);
1199 }
1200
1201 // returns true IFF there's no need to re-initialize the i/v-tables for klass for
1202 // the purpose of checking class loader constraints.
1203 bool SystemDictionaryShared::check_linking_constraints(Thread* current, InstanceKlass* klass) {
1204 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1205 LogTarget(Info, class, loader, constraints) log;
1206 if (klass->defined_by_boot_loader()) {
1207 // No class loader constraint check performed for boot classes.
1208 return true;
1209 }
1210 if (klass->defined_by_platform_loader() || klass->defined_by_app_loader()) {
1211 RunTimeClassInfo* info = RunTimeClassInfo::get_for(klass);
1212 assert(info != nullptr, "Sanity");
1213 if (info->num_loader_constraints() > 0) {
1214 HandleMark hm(current);
1215 for (int i = 0; i < info->num_loader_constraints(); i++) {
1216 RunTimeClassInfo::RTLoaderConstraint* lc = info->loader_constraint_at(i);
1217 Symbol* name = lc->constraint_name();
1218 Handle loader1(current, get_class_loader_by(lc->_loader_type1));
1219 Handle loader2(current, get_class_loader_by(lc->_loader_type2));
1220 if (log.is_enabled()) {
1221 ResourceMark rm(current);
1222 log.print("[CDS add loader constraint for class %s symbol %s loader[0] %s loader[1] %s",
1223 klass->external_name(), name->as_C_string(),
1224 ClassLoaderData::class_loader_data(loader1())->loader_name_and_id(),
1225 ClassLoaderData::class_loader_data(loader2())->loader_name_and_id());
1226 }
1227 if (!SystemDictionary::add_loader_constraint(name, klass, loader1, loader2)) {
1228 // Loader constraint violation has been found. The caller
1229 // will re-layout the vtable/itables to produce the correct
1230 // exception.
1231 if (log.is_enabled()) {
1232 log.print(" failed]");
1233 }
1234 return false;
1235 }
1236 if (log.is_enabled()) {
1237 log.print(" succeeded]");
1238 }
1239 }
1240 return true; // for all recorded constraints added successfully.
1241 }
1242 }
1243 if (log.is_enabled()) {
1244 ResourceMark rm(current);
1245 log.print("[CDS has not recorded loader constraint for class %s]", klass->external_name());
1246 }
1247 return false;
1248 }
1249
1250 void SystemDictionaryShared::copy_linking_constraints_from_preimage(InstanceKlass* klass) {
1251 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1252 JavaThread* current = JavaThread::current();
1253 if (klass->defined_by_platform_loader() || klass->defined_by_app_loader()) {
1254 RunTimeClassInfo* rt_info = RunTimeClassInfo::get_for(klass); // from preimage
1255
1256 if (rt_info->num_loader_constraints() > 0) {
1257 for (int i = 0; i < rt_info->num_loader_constraints(); i++) {
1258 RunTimeClassInfo::RTLoaderConstraint* lc = rt_info->loader_constraint_at(i);
1259 Symbol* name = lc->constraint_name();
1260 Handle loader1(current, get_class_loader_by(lc->_loader_type1));
1261 Handle loader2(current, get_class_loader_by(lc->_loader_type2));
1262 record_linking_constraint(name, klass, loader1, loader2);
1263 }
1264 }
1265 }
1266 }
1267
1268 unsigned int SystemDictionaryShared::hash_for_shared_dictionary(address ptr) {
1269 if (ArchiveBuilder::is_active() && ArchiveBuilder::current()->is_in_buffer_space(ptr)) {
1270 uintx offset = ArchiveBuilder::current()->any_to_offset(ptr);
1271 unsigned int hash = primitive_hash<uintx>(offset);
1272 DEBUG_ONLY({
1273 if (MetaspaceObj::in_aot_cache((const MetaspaceObj*)ptr)) {
1274 assert(hash == SystemDictionaryShared::hash_for_shared_dictionary_quick(ptr), "must be");
1275 }
1276 });
1277 return hash;
1278 } else {
1279 return SystemDictionaryShared::hash_for_shared_dictionary_quick(ptr);
1280 }
1281 }
1282
1283 class CopySharedClassInfoToArchive : StackObj {
1284 CompactHashtableWriter* _writer;
1285 bool _is_builtin;
1286 public:
1287 CopySharedClassInfoToArchive(CompactHashtableWriter* writer,
1288 bool is_builtin)
1289 : _writer(writer), _is_builtin(is_builtin) {}
1290
1291 void do_entry(InstanceKlass* k, DumpTimeClassInfo& info) {
1292 if (!info.is_excluded() && info.is_builtin() == _is_builtin) {
1293 size_t byte_size = info.runtime_info_bytesize();
1294 RunTimeClassInfo* record;
1295 record = (RunTimeClassInfo*)ArchiveBuilder::ro_region_alloc(byte_size);
1296 record->init(info);
1297
1298 unsigned int hash;
1299 Symbol* name = info._klass->name();
1300 name = ArchiveBuilder::current()->get_buffered_addr(name);
1301 hash = SystemDictionaryShared::hash_for_shared_dictionary((address)name);
1302 if (_is_builtin && info._klass->is_hidden()) {
1303 // skip
1304 } else {
1305 _writer->add(hash, AOTCompressedPointers::encode_not_null(record));
1306 }
1307 if (log_is_enabled(Trace, aot, hashtables)) {
1308 ResourceMark rm;
1309 log_trace(aot, hashtables)("%s dictionary: %s", (_is_builtin ? "builtin" : "unregistered"), info._klass->external_name());
1310 }
1311
1312 // Save this for quick runtime lookup of InstanceKlass* -> RunTimeClassInfo*
1313 InstanceKlass* buffered_klass = ArchiveBuilder::current()->get_buffered_addr(info._klass);
1314 RunTimeClassInfo::set_for(buffered_klass, record);
1315 }
1316 }
1317 };
1318
1319 void SystemDictionaryShared::write_dictionary(RunTimeSharedDictionary* dictionary,
1320 bool is_builtin) {
1321 CompactHashtableStats stats;
1322 dictionary->reset();
1323 CompactHashtableWriter writer(_dumptime_table->count_of(is_builtin), &stats);
1324 CopySharedClassInfoToArchive copy(&writer, is_builtin);
1325 assert_lock_strong(DumpTimeTable_lock);
1326 _dumptime_table->iterate_all_live_classes(©);
1327 writer.dump(dictionary, is_builtin ? "builtin dictionary" : "unregistered dictionary");
1328 }
1329
1330 void SystemDictionaryShared::write_to_archive(bool is_static_archive) {
1331 ArchiveInfo* archive = get_archive(is_static_archive);
1332
1333 write_dictionary(&archive->_builtin_dictionary, true);
1334 write_dictionary(&archive->_unregistered_dictionary, false);
1335 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
1336 LambdaProxyClassDictionary::write_dictionary(is_static_archive);
1337 } else {
1338 LambdaProxyClassDictionary::reset_dictionary(is_static_archive);
1339 }
1340 }
1341
1342 void SystemDictionaryShared::serialize_dictionary_headers(SerializeClosure* soc,
1343 bool is_static_archive) {
1344 ArchiveInfo* archive = get_archive(is_static_archive);
1345
1346 archive->_builtin_dictionary.serialize_header(soc);
1347 archive->_unregistered_dictionary.serialize_header(soc);
1348 LambdaProxyClassDictionary::serialize(soc, is_static_archive);
1349 }
1350
1351 void SystemDictionaryShared::serialize_vm_classes(SerializeClosure* soc) {
1352 for (auto id : EnumRange<vmClassID>{}) {
1353 soc->do_ptr(vmClasses::klass_addr_at(id));
1354 }
1355 }
1356
1357 const RunTimeClassInfo*
1358 SystemDictionaryShared::find_record(RunTimeSharedDictionary* static_dict, RunTimeSharedDictionary* dynamic_dict, Symbol* name) {
1359 if (!CDSConfig::is_using_archive() || !name->in_aot_cache()) {
1360 // The names of all shared classes must also be a shared Symbol.
1361 return nullptr;
1362 }
1363
1364 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(name);
1365 const RunTimeClassInfo* record = nullptr;
1366 if (DynamicArchive::is_mapped()) {
1367 // Use the regenerated holder classes in the dynamic archive as they
1368 // have more methods than those in the base archive.
1369 if (LambdaFormInvokers::may_be_regenerated_class(name)) {
1370 record = dynamic_dict->lookup(name, hash, 0);
1371 if (record != nullptr) {
1372 return record;
1373 }
1374 }
1375 }
1376
1377 if (!AOTMetaspace::in_aot_cache_dynamic_region(name)) {
1378 // The names of all shared classes in the static dict must also be in the
1379 // static archive
1380 record = static_dict->lookup(name, hash, 0);
1381 }
1382
1383 if (record == nullptr && DynamicArchive::is_mapped()) {
1384 record = dynamic_dict->lookup(name, hash, 0);
1385 }
1386
1387 return record;
1388 }
1389
1390 InstanceKlass* SystemDictionaryShared::find_builtin_class(Symbol* name) {
1391 const RunTimeClassInfo* record = find_record(&_static_archive._builtin_dictionary,
1392 &_dynamic_archive._builtin_dictionary,
1393 name);
1394 if (record != nullptr) {
1395 assert(!record->klass()->is_hidden(), "hidden class cannot be looked up by name");
1396 DEBUG_ONLY(check_klass_after_loading(record->klass());)
1397 // We did not save the classfile data of the generated LambdaForm invoker classes,
1398 // so we cannot support CLFH for such classes.
1399 if (record->klass()->is_aot_generated_class() && JvmtiExport::should_post_class_file_load_hook()) {
1400 return nullptr;
1401 }
1402 return record->klass();
1403 } else {
1404 return nullptr;
1405 }
1406 }
1407
1408 void SystemDictionaryShared::update_shared_entry(InstanceKlass* k, int id) {
1409 assert(CDSConfig::is_dumping_static_archive(), "class ID is used only for static dump (from classlist)");
1410 DumpTimeClassInfo* info = get_info(k);
1411 info->_id = id;
1412 }
1413
1414 const char* SystemDictionaryShared::loader_type_for_shared_class(Klass* k) {
1415 assert(k != nullptr, "Sanity");
1416 assert(k->in_aot_cache(), "Must be");
1417 assert(k->is_instance_klass(), "Must be");
1418 InstanceKlass* ik = InstanceKlass::cast(k);
1419 if (ik->defined_by_boot_loader()) {
1420 return "boot_loader";
1421 } else if (ik->defined_by_platform_loader()) {
1422 return "platform_loader";
1423 } else if (ik->defined_by_app_loader()) {
1424 return "app_loader";
1425 } else if (ik->defined_by_other_loaders()) {
1426 return "unregistered_loader";
1427 } else {
1428 return "unknown loader";
1429 }
1430 }
1431
1432 void SystemDictionaryShared::get_all_archived_classes(bool is_static_archive, GrowableArray<Klass*>* classes) {
1433 get_archive(is_static_archive)->_builtin_dictionary.iterate_all([&] (const RunTimeClassInfo* record) {
1434 classes->append(record->klass());
1435 });
1436
1437 get_archive(is_static_archive)->_unregistered_dictionary.iterate_all([&] (const RunTimeClassInfo* record) {
1438 classes->append(record->klass());
1439 });
1440 }
1441
1442 class SharedDictionaryPrinter : StackObj {
1443 outputStream* _st;
1444 int _index;
1445 public:
1446 SharedDictionaryPrinter(outputStream* st) : _st(st), _index(0) {}
1447
1448 void do_value(const RunTimeClassInfo* record) {
1449 ResourceMark rm;
1450 _st->print_cr("%4d: %s %s", _index++, record->klass()->external_name(),
1451 SystemDictionaryShared::loader_type_for_shared_class(record->klass()));
1452 if (record->klass()->array_klasses() != nullptr) {
1453 record->klass()->array_klasses()->cds_print_value_on(_st);
1454 _st->cr();
1455 }
1456 }
1457 int index() const { return _index; }
1458 };
1459
1460 void SystemDictionaryShared::ArchiveInfo::print_on(const char* prefix,
1461 outputStream* st,
1462 bool is_static_archive) {
1463 st->print_cr("%sShared Dictionary", prefix);
1464 SharedDictionaryPrinter p(st);
1465 st->print_cr("%sShared Builtin Dictionary", prefix);
1466 _builtin_dictionary.iterate_all(&p);
1467 st->print_cr("%sShared Unregistered Dictionary", prefix);
1468 _unregistered_dictionary.iterate_all(&p);
1469 LambdaProxyClassDictionary::print_on(prefix, st, p.index(), is_static_archive);
1470 }
1471
1472 void SystemDictionaryShared::ArchiveInfo::print_table_statistics(const char* prefix,
1473 outputStream* st,
1474 bool is_static_archive) {
1475 st->print_cr("%sArchve Statistics", prefix);
1476 _builtin_dictionary.print_table_statistics(st, "Builtin Shared Dictionary");
1477 _unregistered_dictionary.print_table_statistics(st, "Unregistered Shared Dictionary");
1478 LambdaProxyClassDictionary::print_statistics(st, is_static_archive);
1479 }
1480
1481 void SystemDictionaryShared::print_shared_archive(outputStream* st, bool is_static) {
1482 if (CDSConfig::is_using_archive()) {
1483 if (is_static) {
1484 _static_archive.print_on("", st, true);
1485 } else {
1486 if (DynamicArchive::is_mapped()) {
1487 _dynamic_archive.print_on("Dynamic ", st, false);
1488 }
1489 }
1490 }
1491 }
1492
1493 void SystemDictionaryShared::print_on(outputStream* st) {
1494 print_shared_archive(st, true);
1495 print_shared_archive(st, false);
1496 }
1497
1498 void SystemDictionaryShared::print_table_statistics(outputStream* st) {
1499 if (CDSConfig::is_using_archive()) {
1500 _static_archive.print_table_statistics("Static ", st, true);
1501 if (DynamicArchive::is_mapped()) {
1502 _dynamic_archive.print_table_statistics("Dynamic ", st, false);
1503 }
1504 }
1505 }
1506
1507 bool SystemDictionaryShared::is_dumptime_table_empty() {
1508 assert_lock_strong(DumpTimeTable_lock);
1509 _dumptime_table->update_counts();
1510 if (_dumptime_table->count_of(true) == 0 && _dumptime_table->count_of(false) == 0){
1511 return true;
1512 }
1513 return false;
1514 }