1 /*
2 * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25
26 #include "cds/aotClassFilter.hpp"
27 #include "cds/aotClassLocation.hpp"
28 #include "cds/aotLogging.hpp"
29 #include "cds/aotMetaspace.hpp"
30 #include "cds/archiveBuilder.hpp"
31 #include "cds/archiveUtils.hpp"
32 #include "cds/cdsConfig.hpp"
33 #include "cds/cdsProtectionDomain.hpp"
34 #include "cds/classListParser.hpp"
35 #include "cds/classListWriter.hpp"
36 #include "cds/dumpTimeClassInfo.inline.hpp"
37 #include "cds/dynamicArchive.hpp"
38 #include "cds/filemap.hpp"
39 #include "cds/heapShared.hpp"
40 #include "cds/lambdaFormInvokers.inline.hpp"
41 #include "cds/lambdaProxyClassDictionary.hpp"
42 #include "cds/runTimeClassInfo.hpp"
43 #include "cds/unregisteredClasses.hpp"
44 #include "classfile/classFileStream.hpp"
45 #include "classfile/classLoader.hpp"
46 #include "classfile/classLoaderData.inline.hpp"
47 #include "classfile/classLoaderDataGraph.hpp"
48 #include "classfile/dictionary.hpp"
49 #include "classfile/javaClasses.inline.hpp"
50 #include "classfile/symbolTable.hpp"
51 #include "classfile/systemDictionary.hpp"
52 #include "classfile/systemDictionaryShared.hpp"
53 #include "classfile/verificationType.hpp"
54 #include "classfile/vmClasses.hpp"
55 #include "classfile/vmSymbols.hpp"
56 #include "jfr/jfrEvents.hpp"
57 #include "logging/log.hpp"
58 #include "logging/logStream.hpp"
59 #include "memory/allocation.hpp"
60 #include "memory/metadataFactory.hpp"
61 #include "memory/metaspaceClosure.hpp"
62 #include "memory/oopFactory.hpp"
63 #include "memory/resourceArea.hpp"
64 #include "memory/universe.hpp"
65 #include "oops/compressedKlass.inline.hpp"
66 #include "oops/instanceKlass.hpp"
67 #include "oops/klass.inline.hpp"
68 #include "oops/methodData.hpp"
69 #include "oops/objArrayKlass.hpp"
70 #include "oops/objArrayOop.inline.hpp"
71 #include "oops/oop.inline.hpp"
72 #include "oops/oopHandle.inline.hpp"
73 #include "oops/typeArrayOop.inline.hpp"
74 #include "runtime/arguments.hpp"
75 #include "runtime/handles.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/mutexLocker.hpp"
79 #include "utilities/hashTable.hpp"
80 #include "utilities/stringUtils.hpp"
81
82 SystemDictionaryShared::ArchiveInfo SystemDictionaryShared::_static_archive;
83 SystemDictionaryShared::ArchiveInfo SystemDictionaryShared::_dynamic_archive;
84
85 DumpTimeSharedClassTable* SystemDictionaryShared::_dumptime_table = nullptr;
86 bool SystemDictionaryShared::_finished_exclusion_checks = false;
87
88 // Used by NoClassLoadingMark
89 DEBUG_ONLY(bool SystemDictionaryShared::_class_loading_may_happen = true;)
90
91 #ifdef ASSERT
92 static void check_klass_after_loading(const Klass* k) {
93 #ifdef _LP64
94 if (k != nullptr && UseCompressedClassPointers) {
95 CompressedKlassPointers::check_encodable(k);
96 }
97 #endif
98 }
99 #endif
100
101 InstanceKlass* SystemDictionaryShared::load_shared_class_for_builtin_loader(
102 Symbol* class_name, Handle class_loader, TRAPS) {
103 assert(CDSConfig::is_using_archive(), "must be");
104 InstanceKlass* ik = find_builtin_class(class_name);
105
106 if (ik != nullptr && !ik->shared_loading_failed()) {
107 if ((SystemDictionary::is_system_class_loader(class_loader()) && ik->defined_by_app_loader()) ||
108 (SystemDictionary::is_platform_class_loader(class_loader()) && ik->defined_by_platform_loader())) {
109 SharedClassLoadingMark slm(THREAD, ik);
110 PackageEntry* pkg_entry = CDSProtectionDomain::get_package_entry_from_class(ik, class_loader);
111 Handle protection_domain;
112 if (!class_name->starts_with("jdk/proxy")) // java/lang/reflect/Proxy$ProxyBuilder defines the proxy classes with a null protection domain.
113 {
114 protection_domain = CDSProtectionDomain::init_security_info(class_loader, ik, pkg_entry, CHECK_NULL);
115 }
116 return load_shared_class(ik, class_loader, protection_domain, nullptr, pkg_entry, THREAD);
117 }
118 }
119 return nullptr;
120 }
121
122 // This function is called for loading only UNREGISTERED classes
123 InstanceKlass* SystemDictionaryShared::lookup_from_stream(Symbol* class_name,
124 Handle class_loader,
125 Handle protection_domain,
126 const ClassFileStream* cfs,
127 TRAPS) {
128 if (!CDSConfig::is_using_archive()) {
129 return nullptr;
130 }
131 if (class_name == nullptr) { // don't do this for hidden classes
132 return nullptr;
133 }
134 if (class_loader.is_null() ||
135 SystemDictionary::is_system_class_loader(class_loader()) ||
136 SystemDictionary::is_platform_class_loader(class_loader())) {
137 // Do nothing for the BUILTIN loaders.
138 return nullptr;
139 }
140
141 const RunTimeClassInfo* record = find_record(&_static_archive._unregistered_dictionary,
142 &_dynamic_archive._unregistered_dictionary,
143 class_name);
144 if (record == nullptr) {
145 return nullptr;
146 }
147
148 int clsfile_size = cfs->length();
149 int clsfile_crc32 = ClassLoader::crc32(0, (const char*)cfs->buffer(), cfs->length());
150
151 if (!record->matches(clsfile_size, clsfile_crc32)) {
152 return nullptr;
153 }
154
155 return acquire_class_for_current_thread(record->klass(), class_loader,
156 protection_domain, cfs,
157 THREAD);
158 }
159
160 InstanceKlass* SystemDictionaryShared::acquire_class_for_current_thread(
161 InstanceKlass *ik,
162 Handle class_loader,
163 Handle protection_domain,
164 const ClassFileStream *cfs,
165 TRAPS) {
166 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
167
168 {
169 MutexLocker mu(THREAD, SharedDictionary_lock);
170 if (ik->class_loader_data() != nullptr) {
171 // ik is already loaded (by this loader or by a different loader)
172 // or ik is being loaded by a different thread (by this loader or by a different loader)
173 return nullptr;
174 }
175
176 // No other thread has acquired this yet, so give it to *this thread*
177 ik->set_class_loader_data(loader_data);
178 }
179
180 // No longer holding SharedDictionary_lock
181 // No need to lock, as <ik> can be held only by a single thread.
182
183 // Get the package entry.
184 PackageEntry* pkg_entry = CDSProtectionDomain::get_package_entry_from_class(ik, class_loader);
185
186 // Load and check super/interfaces, restore unshareable info
187 InstanceKlass* shared_klass = load_shared_class(ik, class_loader, protection_domain,
188 cfs, pkg_entry, THREAD);
189 if (shared_klass == nullptr || HAS_PENDING_EXCEPTION) {
190 // TODO: clean up <ik> so it can be used again
191 return nullptr;
192 }
193
194 return shared_klass;
195 }
196
197 // Guaranteed to return non-null value for non-shared classes.
198 // k must not be a shared class.
199 DumpTimeClassInfo* SystemDictionaryShared::get_info(InstanceKlass* k) {
200 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
201 return get_info_locked(k);
202 }
203
204 DumpTimeClassInfo* SystemDictionaryShared::get_info_locked(InstanceKlass* k) {
205 assert_lock_strong(DumpTimeTable_lock);
206 DumpTimeClassInfo* info = _dumptime_table->get_info(k);
207 assert(info != nullptr, "must be");
208 return info;
209 }
210
211 bool SystemDictionaryShared::should_be_excluded_impl(InstanceKlass* k, DumpTimeClassInfo* info) {
212 assert_lock_strong(DumpTimeTable_lock);
213
214 if (!info->has_checked_exclusion()) {
215 check_exclusion_for_self_and_dependencies(k);
216 assert(info->has_checked_exclusion(), "must be");
217 }
218
219 return info->is_excluded();
220 }
221
222 // <func> returns bool and takes a single parameter of Symbol*
223 // The return value indicates whether we want to keep on iterating or not.
224 template<typename Function>
225 void SystemDictionaryShared::iterate_verification_constraint_names(InstanceKlass* k, DumpTimeClassInfo* info, Function func) {
226 int n = info->num_verifier_constraints();
227 bool cont; // continue iterating?
228 for (int i = 0; i < n; i++) {
229 cont = func(info->verifier_constraint_name_at(i));
230 if (!cont) {
231 return; // early termination
232 }
233 Symbol* from_name = info->verifier_constraint_from_name_at(i);
234 if (from_name != nullptr) {
235 cont = func(from_name);
236 if (!cont) {
237 return; // early termination
238 }
239 }
240 }
241 }
242
243 // This is a table of classes that need to be checked for exclusion.
244 class SystemDictionaryShared::ExclusionCheckCandidates
245 : public HashTable<InstanceKlass*, DumpTimeClassInfo*, 15889> {
246 void add_candidate(InstanceKlass* k) {
247 if (contains(k)) {
248 return;
249 }
250 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(k)) {
251 return;
252 }
253
254 DumpTimeClassInfo* info = SystemDictionaryShared::get_info_locked(k);
255 if (info->has_checked_exclusion()) {
256 // We have check exclusion of k and all of its dependencies, so there's no need to check again.
257 return;
258 }
259
260 put(k, info);
261
262 if (!k->is_loaded()) {
263 // super types are not yet initialized for k.
264 return;
265 }
266
267 InstanceKlass* super = k->java_super();
268 if (super != nullptr) {
269 add_candidate(super);
270 }
271
272 Array<InstanceKlass*>* interfaces = k->local_interfaces();
273 int len = interfaces->length();
274 for (int i = 0; i < len; i++) {
275 add_candidate(interfaces->at(i));
276 }
277
278 InstanceKlass* nest_host = k->nest_host_or_null();
279 if (nest_host != nullptr && nest_host != k) {
280 add_candidate(nest_host);
281 }
282
283 if (CDSConfig::is_preserving_verification_constraints()) {
284 SystemDictionaryShared::iterate_verification_constraint_names(k, info, [&] (Symbol* constraint_class_name) {
285 Klass* constraint_bottom_class = find_verification_constraint_bottom_class(k, constraint_class_name);
286 if (constraint_bottom_class != nullptr && constraint_bottom_class->is_instance_klass()) {
287 add_candidate(InstanceKlass::cast(constraint_bottom_class));
288 }
289 return true; // Keep iterating.
290 });
291 }
292 }
293
294 public:
295 ExclusionCheckCandidates(InstanceKlass* k) {
296 add_candidate(k);
297 }
298 };
299
300 // A class X is excluded if check_self_exclusion() returns true for X or any of
301 // X's "exclusion dependency" classes, which include:
302 // - ik's super types
303 // - ik's nest host (if any)
304 //
305 // plus, if CDSConfig::is_preserving_verification_constraints()==true:
306 // - ik's verification constraints. These are the classes used in assignability checks
307 // when verifying ik's bytecodes.
308 //
309 // This method ensure that exclusion check is performed on X and all of its exclusion dependencies.
310 void SystemDictionaryShared::check_exclusion_for_self_and_dependencies(InstanceKlass* ik) {
311 assert_lock_strong(DumpTimeTable_lock);
312 ResourceMark rm;
313
314 // This will recursively find ik and all of its exclusion dependencies that have not yet been checked.
315 ExclusionCheckCandidates candidates(ik);
316
317 // (1) Check each class to see if it should be excluded due to its own problems
318 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) {
319 if (check_self_exclusion(k)) {
320 info->set_excluded();
321 }
322 });
323
324 // (2) Check each class to see if it should be excluded because of problems in a depeendency class
325 while (true) {
326 bool found_new_exclusion = false;
327
328 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) {
329 if (!info->is_excluded() && check_dependencies_exclusion(k, info)) {
330 info->set_excluded();
331 found_new_exclusion = true;
332 }
333 });
334
335 // Algorithm notes:
336 //
337 // The dependencies form a directed graph, possibly cyclic. Class X is excluded
338 // if it has at least one directed path that reaches class Y, where
339 // check_self_exclusion(Y) returns true.
340 //
341 // Because of the possibility of cycles in the graph, we cannot use simple
342 // recursion. Otherwise we will either never terminate, or will miss some paths.
343 //
344 // Hence, we keep doing a linear scan of the candidates until we stop finding
345 // new exclusions.
346 //
347 // In the worst case, we find one exclusion per iteration of the while loop,
348 // so the while loop gets executed O(N^2) times. However, in reality we have
349 // very few exclusions, so in most cases the while loop executes only once, and we
350 // walk each edge in the dependencies graph exactly once.
351 if (!found_new_exclusion) {
352 break;
353 }
354 }
355 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) {
356 // All candidates have been fully checked, so we don't need to check them again.
357 info->set_has_checked_exclusion();
358 });
359 }
360
361 void SystemDictionaryShared::log_exclusion(InstanceKlass* k, const char* reason, bool is_warning) {
362 ResourceMark rm;
363 if (is_warning) {
364 aot_log_warning(aot)("Skipping %s: %s", k->name()->as_C_string(), reason);
365 } else {
366 aot_log_info(aot)("Skipping %s: %s", k->name()->as_C_string(), reason);
367 }
368 }
369
370 bool SystemDictionaryShared::is_jfr_event_class(InstanceKlass *k) {
371 while (k) {
372 if (k->name()->equals("jdk/internal/event/Event")) {
373 return true;
374 }
375 k = k->super();
376 }
377 return false;
378 }
379
380 bool SystemDictionaryShared::is_early_klass(InstanceKlass* ik) {
381 DumpTimeClassInfo* info = _dumptime_table->get(ik);
382 return (info != nullptr) ? info->is_early_klass() : false;
383 }
384
385 bool SystemDictionaryShared::check_self_exclusion(InstanceKlass* k) {
386 bool log_warning = false;
387 const char* error = check_self_exclusion_helper(k, log_warning);
388 if (error != nullptr) {
389 log_exclusion(k, error, log_warning);
390 return true; // Should be excluded
391 } else {
392 return false; // Should not be excluded
393 }
394 }
395
396 const char* SystemDictionaryShared::check_self_exclusion_helper(InstanceKlass* k, bool& log_warning) {
397 assert_lock_strong(DumpTimeTable_lock);
398 if (CDSConfig::is_dumping_final_static_archive() && k->defined_by_other_loaders()
399 && k->in_aot_cache()) {
400 return nullptr; // Do not exclude: unregistered classes are passed from preimage to final image.
401 }
402
403 if (k->is_in_error_state()) {
404 log_warning = true;
405 return "In error state";
406 }
407 if (k->is_scratch_class()) {
408 return "A scratch class";
409 }
410 if (!k->is_loaded()) {
411 return "Not in loaded state";
412 }
413 if (has_been_redefined(k)) {
414 return "Has been redefined";
415 }
416 if (!k->is_hidden() && k->shared_classpath_index() < 0 && is_builtin(k)) {
417 if (k->name()->starts_with("java/lang/invoke/BoundMethodHandle$Species_")) {
418 // This class is dynamically generated by the JDK
419 if (CDSConfig::is_dumping_method_handles()) {
420 k->set_shared_classpath_index(0);
421 } else {
422 return "dynamically generated";
423 }
424 } else {
425 // These are classes loaded from unsupported locations (such as those loaded by JVMTI native
426 // agent during dump time).
427 return "Unsupported location";
428 }
429 }
430 if (k->signers() != nullptr) {
431 // We cannot include signed classes in the archive because the certificates
432 // used during dump time may be different than those used during
433 // runtime (due to expiration, etc).
434 return "Signed JAR";
435 }
436 if (is_jfr_event_class(k)) {
437 // We cannot include JFR event classes because they need runtime-specific
438 // instrumentation in order to work with -XX:FlightRecorderOptions:retransform=false.
439 // There are only a small number of these classes, so it's not worthwhile to
440 // support them and make CDS more complicated.
441 return "JFR event class";
442 }
443
444 if (!k->is_linked()) {
445 if (has_class_failed_verification(k)) {
446 log_warning = true;
447 return "Failed verification";
448 } else if (CDSConfig::is_dumping_aot_linked_classes()) {
449 // Most loaded classes should have been speculatively linked by AOTMetaspace::link_class_for_cds().
450 // Old classes may not be linked if CDSConfig::is_preserving_verification_constraints()==false.
451 // An unlinked class may fail to verify in AOTLinkedClassBulkLoader::init_required_classes_for_loader(),
452 // causing the JVM to fail at bootstrap.
453 return "Unlinked class not supported by AOTClassLinking";
454 } else if (CDSConfig::is_dumping_preimage_static_archive()) {
455 // When dumping the final static archive, we will unconditionally load and link all
456 // classes from the preimage. We don't want to get a VerifyError when linking this class.
457 return "Unlinked class not supported by AOTConfiguration";
458 }
459 } else {
460 if (!k->can_be_verified_at_dumptime()) {
461 // We have an old class that has been linked (e.g., it's been executed during
462 // dump time). This class has been verified using the old verifier, which
463 // doesn't save the verification constraints, so check_verification_constraints()
464 // won't work at runtime.
465 // As a result, we cannot store this class. It must be loaded and fully verified
466 // at runtime.
467 return "Old class has been linked";
468 }
469 }
470
471 if (UnregisteredClasses::check_for_exclusion(k)) {
472 return "used only when dumping CDS archive";
473 }
474
475 return nullptr;
476 }
477
478 // Returns true if DumpTimeClassInfo::is_excluded() is true for at least one of k's exclusion dependencies.
479 bool SystemDictionaryShared::check_dependencies_exclusion(InstanceKlass* k, DumpTimeClassInfo* info) {
480 InstanceKlass* super = k->java_super();
481 if (super != nullptr && is_dependency_excluded(k, super, "super")) {
482 return true;
483 }
484
485 Array<InstanceKlass*>* interfaces = k->local_interfaces();
486 int len = interfaces->length();
487 for (int i = 0; i < len; i++) {
488 InstanceKlass* intf = interfaces->at(i);
489 if (is_dependency_excluded(k, intf, "interface")) {
490 return true;
491 }
492 }
493
494 InstanceKlass* nest_host = k->nest_host_or_null();
495 if (nest_host != nullptr && nest_host != k && is_dependency_excluded(k, nest_host, "nest host class")) {
496 return true;
497 }
498
499 if (CDSConfig::is_preserving_verification_constraints()) {
500 bool excluded = false;
501
502 iterate_verification_constraint_names(k, info, [&] (Symbol* constraint_class_name) {
503 if (check_verification_constraint_exclusion(k, constraint_class_name)) {
504 // If one of the verification constraint class has been excluded, the assignability checks
505 // by the verifier may no longer be valid in the production run. For safety, exclude this class.
506 excluded = true;
507 return false; // terminate iteration; k will be excluded
508 } else {
509 return true; // keep iterating
510 }
511 });
512
513 if (excluded) {
514 // At least one verification constraint class has been excluded
515 return true;
516 }
517 }
518
519 return false;
520 }
521
522 bool SystemDictionaryShared::is_dependency_excluded(InstanceKlass* k, InstanceKlass* dependency, const char* type) {
523 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(dependency)) {
524 return false;
525 }
526 DumpTimeClassInfo* dependency_info = get_info_locked(dependency);
527 if (dependency_info->is_excluded()) {
528 ResourceMark rm;
529 aot_log_info(aot)("Skipping %s: %s %s is excluded", k->name()->as_C_string(), type, dependency->name()->as_C_string());
530 return true;
531 }
532 return false;
533 }
534
535 bool SystemDictionaryShared::check_verification_constraint_exclusion(InstanceKlass* k, Symbol* constraint_class_name) {
536 Klass* constraint_bottom_class = find_verification_constraint_bottom_class(k, constraint_class_name);
537 if (constraint_bottom_class == nullptr) {
538 // We don't have a bottom class (constraint_class_name is a type array), or constraint_class_name
539 // has not been loaded. The latter case happens when the new verifier was checking
540 // if constraint_class_name is assignable to an interface, and found the answer without resolving
541 // constraint_class_name.
542 //
543 // Since this class is not even loaded, it surely cannot be excluded.
544 return false;
545 } else if (constraint_bottom_class->is_instance_klass()) {
546 if (is_dependency_excluded(k, InstanceKlass::cast(constraint_bottom_class), "verification constraint")) {
547 return true;
548 }
549 } else {
550 assert(constraint_bottom_class->is_typeArray_klass(), "must be");
551 }
552
553 return false;
554 }
555
556 Klass* SystemDictionaryShared::find_verification_constraint_bottom_class(InstanceKlass* k, Symbol* constraint_class_name) {
557 Thread* current = Thread::current();
558 Handle loader(current, k->class_loader());
559 Klass* constraint_class = SystemDictionary::find_instance_or_array_klass(current, constraint_class_name, loader);
560 if (constraint_class == nullptr) {
561 return nullptr;
562 }
563
564 if (constraint_class->is_objArray_klass()) {
565 constraint_class = ObjArrayKlass::cast(constraint_class)->bottom_klass();
566 }
567
568 precond(constraint_class->is_typeArray_klass() || constraint_class->is_instance_klass());
569 return constraint_class;
570 }
571
572 bool SystemDictionaryShared::is_builtin_loader(ClassLoaderData* loader_data) {
573 oop class_loader = loader_data->class_loader();
574 return (class_loader == nullptr ||
575 SystemDictionary::is_system_class_loader(class_loader) ||
576 SystemDictionary::is_platform_class_loader(class_loader));
577 }
578
579 bool SystemDictionaryShared::has_platform_or_app_classes() {
580 if (FileMapInfo::current_info()->has_platform_or_app_classes()) {
581 return true;
582 }
583 if (DynamicArchive::is_mapped() &&
584 FileMapInfo::dynamic_info()->has_platform_or_app_classes()) {
585 return true;
586 }
587 return false;
588 }
589
590 // The following stack shows how this code is reached:
591 //
592 // [0] SystemDictionaryShared::find_or_load_shared_class()
593 // [1] JVM_FindLoadedClass
594 // [2] java.lang.ClassLoader.findLoadedClass0()
595 // [3] java.lang.ClassLoader.findLoadedClass()
596 // [4] jdk.internal.loader.BuiltinClassLoader.loadClassOrNull()
597 // [5] jdk.internal.loader.BuiltinClassLoader.loadClass()
598 // [6] jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(), or
599 // jdk.internal.loader.ClassLoaders$PlatformClassLoader.loadClass()
600 //
601 // AppCDS supports fast class loading for these 2 built-in class loaders:
602 // jdk.internal.loader.ClassLoaders$PlatformClassLoader
603 // jdk.internal.loader.ClassLoaders$AppClassLoader
604 // with the following assumptions (based on the JDK core library source code):
605 //
606 // [a] these two loaders use the BuiltinClassLoader.loadClassOrNull() to
607 // load the named class.
608 // [b] BuiltinClassLoader.loadClassOrNull() first calls findLoadedClass(name).
609 // [c] At this point, if we can find the named class inside the
610 // shared_dictionary, we can perform further checks (see
611 // SystemDictionary::is_shared_class_visible) to ensure that this class
612 // was loaded by the same class loader during dump time.
613 //
614 // Given these assumptions, we intercept the findLoadedClass() call to invoke
615 // SystemDictionaryShared::find_or_load_shared_class() to load the shared class from
616 // the archive for the 2 built-in class loaders. This way,
617 // we can improve start-up because we avoid decoding the classfile,
618 // and avoid delegating to the parent loader.
619 //
620 // NOTE: there's a lot of assumption about the Java code. If any of that change, this
621 // needs to be redesigned.
622
623 InstanceKlass* SystemDictionaryShared::find_or_load_shared_class(
624 Symbol* name, Handle class_loader, TRAPS) {
625 InstanceKlass* k = nullptr;
626 if (CDSConfig::is_using_archive()) {
627 if (!has_platform_or_app_classes()) {
628 return nullptr;
629 }
630
631 if (SystemDictionary::is_system_class_loader(class_loader()) ||
632 SystemDictionary::is_platform_class_loader(class_loader())) {
633 ClassLoaderData *loader_data = register_loader(class_loader);
634 Dictionary* dictionary = loader_data->dictionary();
635
636 // Note: currently, find_or_load_shared_class is called only from
637 // JVM_FindLoadedClass and used for PlatformClassLoader and AppClassLoader,
638 // which are parallel-capable loaders, so a lock here is NOT taken.
639 assert(get_loader_lock_or_null(class_loader) == nullptr, "ObjectLocker not required");
640 {
641 MutexLocker mu(THREAD, SystemDictionary_lock);
642 InstanceKlass* check = dictionary->find_class(THREAD, name);
643 if (check != nullptr) {
644 return check;
645 }
646 }
647
648 k = load_shared_class_for_builtin_loader(name, class_loader, THREAD);
649 if (k != nullptr) {
650 SharedClassLoadingMark slm(THREAD, k);
651 k = find_or_define_instance_class(name, class_loader, k, CHECK_NULL);
652 }
653 }
654 }
655
656 DEBUG_ONLY(check_klass_after_loading(k);)
657
658 return k;
659 }
660
661 class UnregisteredClassesTable : public HashTable<
662 Symbol*, InstanceKlass*,
663 15889, // prime number
664 AnyObj::C_HEAP> {};
665
666 static UnregisteredClassesTable* _unregistered_classes_table = nullptr;
667
668 // true == class was successfully added; false == a duplicated class (with the same name) already exists.
669 bool SystemDictionaryShared::add_unregistered_class(Thread* current, InstanceKlass* klass) {
670 // We don't allow duplicated unregistered classes with the same name.
671 // We only archive the first class with that name that succeeds putting
672 // itself into the table.
673 assert(CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled(), "sanity");
674 MutexLocker ml(current, UnregisteredClassesTable_lock, Mutex::_no_safepoint_check_flag);
675 Symbol* name = klass->name();
676 if (_unregistered_classes_table == nullptr) {
677 _unregistered_classes_table = new (mtClass)UnregisteredClassesTable();
678 }
679 bool created;
680 InstanceKlass** v = _unregistered_classes_table->put_if_absent(name, klass, &created);
681 if (created) {
682 name->increment_refcount();
683 }
684 return (klass == *v);
685 }
686
687 InstanceKlass* SystemDictionaryShared::get_unregistered_class(Symbol* name) {
688 assert(CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled(), "sanity");
689 if (_unregistered_classes_table == nullptr) {
690 return nullptr;
691 }
692 InstanceKlass** k = _unregistered_classes_table->get(name);
693 return k != nullptr ? *k : nullptr;
694 }
695
696 void SystemDictionaryShared::copy_unregistered_class_size_and_crc32(InstanceKlass* klass) {
697 precond(CDSConfig::is_dumping_final_static_archive());
698 precond(klass->in_aot_cache());
699
700 // A shared class must have a RunTimeClassInfo record
701 const RunTimeClassInfo* record = find_record(&_static_archive._unregistered_dictionary,
702 nullptr, klass->name());
703 precond(record != nullptr);
704 precond(record->klass() == klass);
705
706 DumpTimeClassInfo* info = get_info(klass);
707 info->_clsfile_size = record->crc()->_clsfile_size;
708 info->_clsfile_crc32 = record->crc()->_clsfile_crc32;
709 }
710
711 void SystemDictionaryShared::set_shared_class_misc_info(InstanceKlass* k, ClassFileStream* cfs) {
712 assert(CDSConfig::is_dumping_archive(), "sanity");
713 assert(!is_builtin(k), "must be unregistered class");
714 DumpTimeClassInfo* info = get_info(k);
715 info->_clsfile_size = cfs->length();
716 info->_clsfile_crc32 = ClassLoader::crc32(0, (const char*)cfs->buffer(), cfs->length());
717 }
718
719 void SystemDictionaryShared::initialize() {
720 if (CDSConfig::is_dumping_archive()) {
721 _dumptime_table = new (mtClass) DumpTimeSharedClassTable;
722 LambdaProxyClassDictionary::dumptime_init();
723 if (CDSConfig::is_dumping_heap()) {
724 HeapShared::init_dumping();
725 }
726 }
727 }
728
729 void SystemDictionaryShared::init_dumptime_info(InstanceKlass* k) {
730 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
731 assert(SystemDictionaryShared::class_loading_may_happen(), "sanity");
732 DumpTimeClassInfo* info = _dumptime_table->allocate_info(k);
733 if (AOTClassFilter::is_aot_tooling_class(k)) {
734 info->set_is_aot_tooling_class();
735 }
736 }
737
738 void SystemDictionaryShared::remove_dumptime_info(InstanceKlass* k) {
739 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
740 _dumptime_table->remove(k);
741 }
742
743 void SystemDictionaryShared::handle_class_unloading(InstanceKlass* klass) {
744 if (CDSConfig::is_dumping_archive()) {
745 remove_dumptime_info(klass);
746 }
747
748 if (CDSConfig::is_dumping_archive() || ClassListWriter::is_enabled()) {
749 MutexLocker ml(Thread::current(), UnregisteredClassesTable_lock, Mutex::_no_safepoint_check_flag);
750 if (_unregistered_classes_table != nullptr) {
751 // Remove the class from _unregistered_classes_table: keep the entry but
752 // set it to null. This ensure no classes with the same name can be
753 // added again.
754 InstanceKlass** v = _unregistered_classes_table->get(klass->name());
755 if (v != nullptr) {
756 *v = nullptr;
757 }
758 }
759 } else {
760 assert(_unregistered_classes_table == nullptr, "must not be used");
761 }
762
763 if (ClassListWriter::is_enabled()) {
764 ClassListWriter cw;
765 cw.handle_class_unloading((const InstanceKlass*)klass);
766 }
767 }
768
769 void SystemDictionaryShared::init_dumptime_info_from_preimage(InstanceKlass* k) {
770 init_dumptime_info(k);
771 copy_verification_info_from_preimage(k);
772 copy_linking_constraints_from_preimage(k);
773
774 if (SystemDictionary::is_platform_class_loader(k->class_loader())) {
775 AOTClassLocationConfig::dumptime_set_has_platform_classes();
776 } else if (SystemDictionary::is_system_class_loader(k->class_loader())) {
777 AOTClassLocationConfig::dumptime_set_has_app_classes();
778 }
779 }
780
781 // Check if a class or any of its supertypes has been redefined.
782 bool SystemDictionaryShared::has_been_redefined(InstanceKlass* k) {
783 if (k->has_been_redefined()) {
784 return true;
785 }
786 if (k->super() != nullptr && has_been_redefined(k->super())) {
787 return true;
788 }
789 Array<InstanceKlass*>* interfaces = k->local_interfaces();
790 int len = interfaces->length();
791 for (int i = 0; i < len; i++) {
792 if (has_been_redefined(interfaces->at(i))) {
793 return true;
794 }
795 }
796 return false;
797 }
798
799 // k is a class before relocating by ArchiveBuilder
800 void SystemDictionaryShared::validate_before_archiving(InstanceKlass* k) {
801 ResourceMark rm;
802 const char* name = k->name()->as_C_string();
803 DumpTimeClassInfo* info = _dumptime_table->get(k);
804 assert(!class_loading_may_happen(), "class loading must be disabled");
805 guarantee(info != nullptr, "Class %s must be entered into _dumptime_table", name);
806 guarantee(!info->is_excluded(), "Should not attempt to archive excluded class %s", name);
807 if (is_builtin(k)) {
808 if (k->is_hidden()) {
809 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
810 assert(LambdaProxyClassDictionary::is_registered_lambda_proxy_class(k), "unexpected hidden class %s", name);
811 }
812 }
813 guarantee(!k->defined_by_other_loaders(),
814 "Class loader type must be set for BUILTIN class %s", name);
815
816 } else {
817 guarantee(k->defined_by_other_loaders(),
818 "Class loader type must not be set for UNREGISTERED class %s", name);
819 }
820 }
821
822 class UnregisteredClassesDuplicationChecker : StackObj {
823 GrowableArray<InstanceKlass*> _list;
824 Thread* _thread;
825 public:
826 UnregisteredClassesDuplicationChecker() : _thread(Thread::current()) {}
827
828 void do_entry(InstanceKlass* k, DumpTimeClassInfo& info) {
829 if (!SystemDictionaryShared::is_builtin(k)) {
830 _list.append(k);
831 }
832 }
833
834 static int compare_by_loader(InstanceKlass** a, InstanceKlass** b) {
835 ClassLoaderData* loader_a = a[0]->class_loader_data();
836 ClassLoaderData* loader_b = b[0]->class_loader_data();
837
838 if (loader_a != loader_b) {
839 return primitive_compare(loader_a, loader_b);
840 } else {
841 return primitive_compare(a[0], b[0]);
842 }
843 }
844
845 void mark_duplicated_classes() {
846 // Two loaders may load two identical or similar hierarchies of classes. If we
847 // check for duplication in random order, we may end up excluding important base classes
848 // in both hierarchies, causing most of the classes to be excluded.
849 // We sort the classes by their loaders. This way we're likely to archive
850 // all classes in the one of the two hierarchies.
851 _list.sort(compare_by_loader);
852 for (int i = 0; i < _list.length(); i++) {
853 InstanceKlass* k = _list.at(i);
854 bool i_am_first = SystemDictionaryShared::add_unregistered_class(_thread, k);
855 if (!i_am_first) {
856 SystemDictionaryShared::log_exclusion(k, "Duplicated unregistered class");
857 SystemDictionaryShared::set_excluded_locked(k);
858 }
859 }
860 }
861 };
862
863 void SystemDictionaryShared::link_all_exclusion_check_candidates(InstanceKlass* ik) {
864 bool need_to_link = false;
865 {
866 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
867 ExclusionCheckCandidates candidates(ik);
868
869 candidates.iterate_all([&] (InstanceKlass* k, DumpTimeClassInfo* info) {
870 if (!k->is_linked()) {
871 need_to_link = true;
872 }
873 });
874 }
875 if (need_to_link) {
876 JavaThread* THREAD = JavaThread::current();
877 if (log_is_enabled(Info, aot, link)) {
878 ResourceMark rm(THREAD);
879 log_info(aot, link)("Link all loaded classes for %s", ik->external_name());
880 }
881 AOTMetaspace::link_all_loaded_classes(THREAD);
882 }
883 }
884
885 // Returns true if the class should be excluded. This can be called by
886 // AOTConstantPoolResolver before or after we enter the CDS safepoint.
887 // When called before the safepoint, we need to link the class so that
888 // it can be checked by should_be_excluded_impl().
889 bool SystemDictionaryShared::should_be_excluded(Klass* k) {
890 if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(k)) {
891 // We have reached a super type that's already in the base archive. Treat it
892 // as "not excluded".
893 return false;
894 }
895
896 if (k->is_objArray_klass()) {
897 return should_be_excluded(ObjArrayKlass::cast(k)->bottom_klass());
898 } else if (!k->is_instance_klass()) {
899 assert(k->is_typeArray_klass(), "must be");
900 return false;
901 } else {
902 InstanceKlass* ik = InstanceKlass::cast(k);
903
904 if (CDSConfig::is_dumping_final_static_archive() && _finished_exclusion_checks &&
905 !SafepointSynchronize::is_at_safepoint()) {
906 // This is called from the AOT compiler.
907 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
908 DumpTimeClassInfo* p = get_info_locked(ik);
909 if (p->is_excluded()) {
910 return true;
911 } else if (!p->has_checked_exclusion()) {
912 // This is a class that was loaded after we exited the AOT safepoint. This
913 // class is not in the AOT cache, so it must be considered as "excluded"
914 return true;
915 } else {
916 return false;
917 }
918 }
919
920 assert(CDSConfig::is_dumping_archive(), "sanity");
921 assert(CDSConfig::current_thread_is_vm_or_dumper(), "sanity");
922
923 if (!SafepointSynchronize::is_at_safepoint()) {
924 {
925 // fast path
926 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
927 DumpTimeClassInfo* p = get_info_locked(ik);
928 if (p->has_checked_exclusion()) {
929 return p->is_excluded();
930 }
931 }
932
933 link_all_exclusion_check_candidates(ik);
934
935 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
936 DumpTimeClassInfo* p = get_info_locked(ik);
937 return should_be_excluded_impl(ik, p);
938 } else {
939 // When called within the CDS safepoint, the correctness of this function
940 // relies on the call to AOTMetaspace::link_all_loaded_classes()
941 // that happened right before we enter the CDS safepoint.
942 //
943 // Do not call this function in other types of safepoints. For example, if this
944 // is called in a GC safepoint, a klass may be improperly excluded because some
945 // of its verification constraints have not yet been linked.
946 assert(CDSConfig::is_at_aot_safepoint(), "Do not call this function in any other safepoint");
947
948 // No need to check for is_linked() as all eligible classes should have
949 // already been linked in AOTMetaspace::link_class_for_cds().
950 // Don't take DumpTimeTable_lock as we are in safepoint.
951 DumpTimeClassInfo* p = _dumptime_table->get(ik);
952 if (p->is_excluded()) {
953 return true;
954 }
955 return should_be_excluded_impl(ik, p);
956 }
957 }
958 }
959
960 void SystemDictionaryShared::finish_exclusion_checks() {
961 assert_at_safepoint();
962 if (CDSConfig::is_dumping_dynamic_archive() || CDSConfig::is_dumping_preimage_static_archive()) {
963 // Do this first -- if a base class is excluded due to duplication,
964 // all of its subclasses will also be excluded.
965 ResourceMark rm;
966 UnregisteredClassesDuplicationChecker dup_checker;
967 _dumptime_table->iterate_all_live_classes(&dup_checker);
968 dup_checker.mark_duplicated_classes();
969 }
970
971 _dumptime_table->iterate_all_live_classes([&] (InstanceKlass* k, DumpTimeClassInfo& info) {
972 SystemDictionaryShared::should_be_excluded_impl(k, &info);
973 });
974
975 _dumptime_table->update_counts();
976 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
977 LambdaProxyClassDictionary::cleanup_dumptime_table();
978 }
979 _finished_exclusion_checks = true;
980 }
981
982 bool SystemDictionaryShared::is_excluded_class(InstanceKlass* k) {
983 assert(!class_loading_may_happen(), "class loading must be disabled");
984 assert_lock_strong(DumpTimeTable_lock);
985 assert(CDSConfig::is_dumping_archive(), "sanity");
986 DumpTimeClassInfo* p = get_info_locked(k);
987 return p->is_excluded();
988 }
989
990 void SystemDictionaryShared::set_excluded_locked(InstanceKlass* k) {
991 assert_lock_strong(DumpTimeTable_lock);
992 assert(CDSConfig::is_dumping_archive(), "sanity");
993 DumpTimeClassInfo* info = get_info_locked(k);
994 info->set_excluded();
995 }
996
997 void SystemDictionaryShared::set_excluded(InstanceKlass* k) {
998 assert(CDSConfig::is_dumping_archive(), "sanity");
999 DumpTimeClassInfo* info = get_info(k);
1000 info->set_excluded();
1001 }
1002
1003 void SystemDictionaryShared::set_class_has_failed_verification(InstanceKlass* ik) {
1004 assert(CDSConfig::is_dumping_archive(), "sanity");
1005 DumpTimeClassInfo* p = get_info(ik);
1006 p->set_failed_verification();
1007 }
1008
1009 bool SystemDictionaryShared::has_class_failed_verification(InstanceKlass* ik) {
1010 assert(CDSConfig::is_dumping_archive(), "sanity");
1011 DumpTimeClassInfo* p = _dumptime_table->get(ik);
1012 return (p == nullptr) ? false : p->failed_verification();
1013 }
1014
1015 void SystemDictionaryShared::set_from_class_file_load_hook(InstanceKlass* ik) {
1016 log_exclusion(ik, "From ClassFileLoadHook");
1017 set_excluded(ik);
1018 }
1019
1020 void SystemDictionaryShared::dumptime_classes_do(MetaspaceClosure* it) {
1021 assert_lock_strong(DumpTimeTable_lock);
1022
1023 auto do_klass = [&] (InstanceKlass* k, DumpTimeClassInfo& info) {
1024 if (CDSConfig::is_dumping_final_static_archive() && !k->is_loaded()) {
1025 assert(k->defined_by_other_loaders(), "must be");
1026 info.metaspace_pointers_do(it);
1027 } else if (k->is_loader_alive() && !info.is_excluded()) {
1028 info.metaspace_pointers_do(it);
1029 }
1030 };
1031 _dumptime_table->iterate_all_live_classes(do_klass);
1032
1033 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
1034 LambdaProxyClassDictionary::dumptime_classes_do(it);
1035 }
1036 }
1037
1038 // Called from VerificationType::is_reference_assignable_from() before performing the assignability check of
1039 // T1 must be assignable from T2
1040 // Where:
1041 // L is the class loader of <k>
1042 // T1 is the type resolved by L using the name <name>
1043 // T2 is the type resolved by L using the name <from_name>
1044 //
1045 // The meaning of (*skip_assignability_check):
1046 // true: is_reference_assignable_from() should SKIP the assignability check
1047 // false: is_reference_assignable_from() should COMPLETE the assignability check
1048 void SystemDictionaryShared::add_verification_constraint(InstanceKlass* k, Symbol* name,
1049 Symbol* from_name, bool from_field_is_protected, bool from_is_array, bool from_is_object,
1050 bool* skip_assignability_check) {
1051 assert(CDSConfig::is_dumping_archive(), "sanity");
1052 if (CDSConfig::is_dumping_dynamic_archive() && k->in_aot_cache()) {
1053 // k is a new class in the static archive, but one of its supertypes is an old class, so k wasn't
1054 // verified during dump time. No need to record constraints as k won't be included in the dynamic archive.
1055 return;
1056 }
1057 if (CDSConfig::is_dumping_aot_linked_classes() && is_builtin(k)) {
1058 // There's no need to save verification constraints
1059 // TODO -- double check the logic before integrating into mainline!!
1060 return;
1061 }
1062
1063 DumpTimeClassInfo* info = get_info(k);
1064 info->add_verification_constraint(name, from_name, from_field_is_protected,
1065 from_is_array, from_is_object);
1066
1067 if (CDSConfig::is_dumping_classic_static_archive() && !is_builtin(k)) {
1068 // This applies ONLY to the "classic" CDS static dump, which reads the list of
1069 // unregistered classes (those intended for custom class loaders) from the classlist
1070 // and loads them using jdk.internal.misc.CDS$UnregisteredClassLoader.
1071 //
1072 // When the classlist contains an unregistered class k, the supertypes of k are also
1073 // recorded in the classlist. However, the classlist does not contain information about
1074 // any class X that's not a supertype of k but is needed in the verification of k.
1075 // As a result, CDS$UnregisteredClassLoader will not know how to resolve X.
1076 //
1077 // Therefore, we tell the verifier to refrain from resolving X. Instead, X is recorded
1078 // (symbolically) in the verification constraints of k. In the production run,
1079 // when k is loaded, we will go through its verification constraints and resolve X to complete
1080 // the is_reference_assignable_from() checks.
1081 *skip_assignability_check = true;
1082 } else {
1083 // In all other cases, we are using an *actual* class loader to load k, so it should be able
1084 // to resolve any types that are needed for the verification of k.
1085 *skip_assignability_check = false;
1086 }
1087 }
1088
1089 // When the old verifier is verifying the class <ik> at dump time, it tries to resolve a
1090 // class with the given <name>. For the verification result to be valid at run time, we must
1091 // ensure that <name> resolves to the exact same Klass as in dump time.
1092 void SystemDictionaryShared::add_old_verification_constraint(Thread* current, InstanceKlass* ik, Symbol* name) {
1093 precond(CDSConfig::is_preserving_verification_constraints());
1094 DumpTimeClassInfo* info = get_info(ik);
1095 info->add_verification_constraint(name);
1096 }
1097
1098 void SystemDictionaryShared::add_enum_klass_static_field(InstanceKlass* ik, int root_index) {
1099 assert(CDSConfig::is_dumping_heap(), "sanity");
1100 DumpTimeClassInfo* info = get_info_locked(ik);
1101 info->add_enum_klass_static_field(root_index);
1102 }
1103
1104 void SystemDictionaryShared::check_verification_constraints(InstanceKlass* klass,
1105 TRAPS) {
1106 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1107 RunTimeClassInfo* record = RunTimeClassInfo::get_for(klass);
1108
1109 int length = record->num_verifier_constraints();
1110 if (length > 0) {
1111 for (int i = 0; i < length; i++) {
1112 RunTimeClassInfo::RTVerifierConstraint* vc = record->verifier_constraint_at(i);
1113 Symbol* name = vc->name();
1114 Symbol* from_name = vc->from_name();
1115
1116 if (from_name == nullptr) {
1117 // This is for old verifier. No need to check, as we can guarantee that all classes checked by
1118 // the old verifier during AOT training phase cannot be replaced in the asembly phase.
1119 precond(CDSConfig::is_dumping_final_static_archive());
1120 continue;
1121 }
1122
1123 if (log_is_enabled(Trace, aot, verification)) {
1124 ResourceMark rm(THREAD);
1125 log_trace(aot, verification)("check_verification_constraint: %s: %s must be subclass of %s [0x%x]",
1126 klass->external_name(), from_name->as_klass_external_name(),
1127 name->as_klass_external_name(), record->verifier_constraint_flag(i));
1128 }
1129
1130 bool ok = VerificationType::resolve_and_check_assignability(klass, name, from_name,
1131 record->from_field_is_protected(i), record->from_is_array(i), record->from_is_object(i), CHECK);
1132 if (!ok) {
1133 ResourceMark rm(THREAD);
1134 stringStream ss;
1135
1136 ss.print_cr("Bad type on operand stack");
1137 ss.print_cr("Exception Details:");
1138 ss.print_cr(" Location:\n %s", klass->name()->as_C_string());
1139 ss.print_cr(" Reason:\n Type '%s' is not assignable to '%s'",
1140 from_name->as_quoted_ascii(), name->as_quoted_ascii());
1141 THROW_MSG(vmSymbols::java_lang_VerifyError(), ss.as_string());
1142 }
1143 }
1144 }
1145 }
1146
1147 void SystemDictionaryShared::copy_verification_info_from_preimage(InstanceKlass* klass) {
1148 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1149 DumpTimeClassInfo* dt_info = get_info(klass);
1150 RunTimeClassInfo* rt_info = RunTimeClassInfo::get_for(klass); // from preimage
1151
1152 int length = rt_info->num_verifier_constraints();
1153 if (length > 0) {
1154 for (int i = 0; i < length; i++) {
1155 RunTimeClassInfo::RTVerifierConstraint* vc = rt_info->verifier_constraint_at(i);
1156 Symbol* name = vc->name();
1157 Symbol* from_name = vc->from_name();
1158
1159 dt_info->add_verification_constraint(name, from_name,
1160 rt_info->from_field_is_protected(i), rt_info->from_is_array(i), rt_info->from_is_object(i));
1161 }
1162 }
1163 }
1164
1165 static oop get_class_loader_by(char type) {
1166 if (type == (char)ClassLoader::BOOT_LOADER) {
1167 return (oop)nullptr;
1168 } else if (type == (char)ClassLoader::PLATFORM_LOADER) {
1169 return SystemDictionary::java_platform_loader();
1170 } else {
1171 assert (type == (char)ClassLoader::APP_LOADER, "Sanity");
1172 return SystemDictionary::java_system_loader();
1173 }
1174 }
1175
1176 // Record class loader constraints that are checked inside
1177 // InstanceKlass::link_class(), so that these can be checked quickly
1178 // at runtime without laying out the vtable/itables.
1179 void SystemDictionaryShared::record_linking_constraint(Symbol* name, InstanceKlass* klass,
1180 Handle loader1, Handle loader2) {
1181 // A linking constraint check is executed when:
1182 // - klass extends or implements type S
1183 // - klass overrides method S.M(...) with X.M
1184 // - If klass defines the method M, X is
1185 // the same as klass.
1186 // - If klass does not define the method M,
1187 // X must be a supertype of klass and X.M is
1188 // a default method defined by X.
1189 // - loader1 = X->class_loader()
1190 // - loader2 = S->class_loader()
1191 // - loader1 != loader2
1192 // - M's parameter(s) include an object type T
1193 // We require that
1194 // - whenever loader1 and loader2 try to
1195 // resolve the type T, they must always resolve to
1196 // the same InstanceKlass.
1197 // NOTE: type T may or may not be currently resolved in
1198 // either of these two loaders. The check itself does not
1199 // try to resolve T.
1200 oop klass_loader = klass->class_loader();
1201
1202 if (!is_system_class_loader(klass_loader) &&
1203 !is_platform_class_loader(klass_loader)) {
1204 // If klass is loaded by system/platform loaders, we can
1205 // guarantee that klass and S must be loaded by the same
1206 // respective loader between dump time and run time, and
1207 // the exact same check on (name, loader1, loader2) will
1208 // be executed. Hence, we can cache this check and execute
1209 // it at runtime without walking the vtable/itables.
1210 //
1211 // This cannot be guaranteed for classes loaded by other
1212 // loaders, so we bail.
1213 return;
1214 }
1215
1216 assert(is_builtin(klass), "must be");
1217 assert(klass_loader != nullptr, "should not be called for boot loader");
1218 assert(loader1 != loader2, "must be");
1219
1220 if (CDSConfig::is_dumping_dynamic_archive() && Thread::current()->is_VM_thread()) {
1221 // We are re-laying out the vtable/itables of the *copy* of
1222 // a class during the final stage of dynamic dumping. The
1223 // linking constraints for this class has already been recorded.
1224 return;
1225 }
1226 assert(!Thread::current()->is_VM_thread(), "must be");
1227
1228 assert(CDSConfig::is_dumping_archive(), "sanity");
1229 DumpTimeClassInfo* info = get_info(klass);
1230 info->record_linking_constraint(name, loader1, loader2);
1231 }
1232
1233 // returns true IFF there's no need to re-initialize the i/v-tables for klass for
1234 // the purpose of checking class loader constraints.
1235 bool SystemDictionaryShared::check_linking_constraints(Thread* current, InstanceKlass* klass) {
1236 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1237 LogTarget(Info, class, loader, constraints) log;
1238 if (klass->defined_by_boot_loader()) {
1239 // No class loader constraint check performed for boot classes.
1240 return true;
1241 }
1242 if (klass->defined_by_platform_loader() || klass->defined_by_app_loader()) {
1243 RunTimeClassInfo* info = RunTimeClassInfo::get_for(klass);
1244 assert(info != nullptr, "Sanity");
1245 if (info->num_loader_constraints() > 0) {
1246 HandleMark hm(current);
1247 for (int i = 0; i < info->num_loader_constraints(); i++) {
1248 RunTimeClassInfo::RTLoaderConstraint* lc = info->loader_constraint_at(i);
1249 Symbol* name = lc->constraint_name();
1250 Handle loader1(current, get_class_loader_by(lc->_loader_type1));
1251 Handle loader2(current, get_class_loader_by(lc->_loader_type2));
1252 if (log.is_enabled()) {
1253 ResourceMark rm(current);
1254 log.print("[CDS add loader constraint for class %s symbol %s loader[0] %s loader[1] %s",
1255 klass->external_name(), name->as_C_string(),
1256 ClassLoaderData::class_loader_data(loader1())->loader_name_and_id(),
1257 ClassLoaderData::class_loader_data(loader2())->loader_name_and_id());
1258 }
1259 if (!SystemDictionary::add_loader_constraint(name, klass, loader1, loader2)) {
1260 // Loader constraint violation has been found. The caller
1261 // will re-layout the vtable/itables to produce the correct
1262 // exception.
1263 if (log.is_enabled()) {
1264 log.print(" failed]");
1265 }
1266 return false;
1267 }
1268 if (log.is_enabled()) {
1269 log.print(" succeeded]");
1270 }
1271 }
1272 return true; // for all recorded constraints added successfully.
1273 }
1274 }
1275 if (log.is_enabled()) {
1276 ResourceMark rm(current);
1277 log.print("[CDS has not recorded loader constraint for class %s]", klass->external_name());
1278 }
1279 return false;
1280 }
1281
1282 void SystemDictionaryShared::copy_linking_constraints_from_preimage(InstanceKlass* klass) {
1283 assert(CDSConfig::is_using_archive(), "called at run time with CDS enabled only");
1284 JavaThread* current = JavaThread::current();
1285 if (klass->defined_by_platform_loader() || klass->defined_by_app_loader()) {
1286 RunTimeClassInfo* rt_info = RunTimeClassInfo::get_for(klass); // from preimage
1287
1288 if (rt_info->num_loader_constraints() > 0) {
1289 for (int i = 0; i < rt_info->num_loader_constraints(); i++) {
1290 RunTimeClassInfo::RTLoaderConstraint* lc = rt_info->loader_constraint_at(i);
1291 Symbol* name = lc->constraint_name();
1292 Handle loader1(current, get_class_loader_by(lc->_loader_type1));
1293 Handle loader2(current, get_class_loader_by(lc->_loader_type2));
1294 record_linking_constraint(name, klass, loader1, loader2);
1295 }
1296 }
1297 }
1298 }
1299
1300 unsigned int SystemDictionaryShared::hash_for_shared_dictionary(address ptr) {
1301 if (ArchiveBuilder::is_active() && ArchiveBuilder::current()->is_in_buffer_space(ptr)) {
1302 uintx offset = ArchiveBuilder::current()->any_to_offset(ptr);
1303 unsigned int hash = primitive_hash<uintx>(offset);
1304 DEBUG_ONLY({
1305 if (MetaspaceObj::in_aot_cache((const MetaspaceObj*)ptr)) {
1306 assert(hash == SystemDictionaryShared::hash_for_shared_dictionary_quick(ptr), "must be");
1307 }
1308 });
1309 return hash;
1310 } else {
1311 return SystemDictionaryShared::hash_for_shared_dictionary_quick(ptr);
1312 }
1313 }
1314
1315 class CopySharedClassInfoToArchive : StackObj {
1316 CompactHashtableWriter* _writer;
1317 bool _is_builtin;
1318 ArchiveBuilder *_builder;
1319 public:
1320 CopySharedClassInfoToArchive(CompactHashtableWriter* writer,
1321 bool is_builtin)
1322 : _writer(writer), _is_builtin(is_builtin), _builder(ArchiveBuilder::current()) {}
1323
1324 void do_entry(InstanceKlass* k, DumpTimeClassInfo& info) {
1325 if (!info.is_excluded() && info.is_builtin() == _is_builtin) {
1326 size_t byte_size = info.runtime_info_bytesize();
1327 RunTimeClassInfo* record;
1328 record = (RunTimeClassInfo*)ArchiveBuilder::ro_region_alloc(byte_size);
1329 record->init(info);
1330
1331 unsigned int hash;
1332 Symbol* name = info._klass->name();
1333 name = ArchiveBuilder::current()->get_buffered_addr(name);
1334 hash = SystemDictionaryShared::hash_for_shared_dictionary((address)name);
1335 u4 delta = _builder->buffer_to_offset_u4((address)record);
1336 if (_is_builtin && info._klass->is_hidden()) {
1337 // skip
1338 } else {
1339 _writer->add(hash, delta);
1340 }
1341 if (log_is_enabled(Trace, aot, hashtables)) {
1342 ResourceMark rm;
1343 log_trace(aot, hashtables)("%s dictionary: %s", (_is_builtin ? "builtin" : "unregistered"), info._klass->external_name());
1344 }
1345
1346 // Save this for quick runtime lookup of InstanceKlass* -> RunTimeClassInfo*
1347 InstanceKlass* buffered_klass = ArchiveBuilder::current()->get_buffered_addr(info._klass);
1348 RunTimeClassInfo::set_for(buffered_klass, record);
1349 }
1350 }
1351 };
1352
1353 void SystemDictionaryShared::write_dictionary(RunTimeSharedDictionary* dictionary,
1354 bool is_builtin) {
1355 CompactHashtableStats stats;
1356 dictionary->reset();
1357 CompactHashtableWriter writer(_dumptime_table->count_of(is_builtin), &stats);
1358 CopySharedClassInfoToArchive copy(&writer, is_builtin);
1359 assert_lock_strong(DumpTimeTable_lock);
1360 _dumptime_table->iterate_all_live_classes(©);
1361 writer.dump(dictionary, is_builtin ? "builtin dictionary" : "unregistered dictionary");
1362 }
1363
1364 void SystemDictionaryShared::write_to_archive(bool is_static_archive) {
1365 ArchiveInfo* archive = get_archive(is_static_archive);
1366
1367 write_dictionary(&archive->_builtin_dictionary, true);
1368 write_dictionary(&archive->_unregistered_dictionary, false);
1369 if (CDSConfig::is_dumping_lambdas_in_legacy_mode()) {
1370 LambdaProxyClassDictionary::write_dictionary(is_static_archive);
1371 } else {
1372 LambdaProxyClassDictionary::reset_dictionary(is_static_archive);
1373 }
1374 }
1375
1376 void SystemDictionaryShared::serialize_dictionary_headers(SerializeClosure* soc,
1377 bool is_static_archive) {
1378 ArchiveInfo* archive = get_archive(is_static_archive);
1379
1380 archive->_builtin_dictionary.serialize_header(soc);
1381 archive->_unregistered_dictionary.serialize_header(soc);
1382 LambdaProxyClassDictionary::serialize(soc, is_static_archive);
1383 }
1384
1385 void SystemDictionaryShared::serialize_vm_classes(SerializeClosure* soc) {
1386 for (auto id : EnumRange<vmClassID>{}) {
1387 soc->do_ptr(vmClasses::klass_addr_at(id));
1388 }
1389 }
1390
1391 const RunTimeClassInfo*
1392 SystemDictionaryShared::find_record(RunTimeSharedDictionary* static_dict, RunTimeSharedDictionary* dynamic_dict, Symbol* name) {
1393 if (!CDSConfig::is_using_archive() || !name->in_aot_cache()) {
1394 // The names of all shared classes must also be a shared Symbol.
1395 return nullptr;
1396 }
1397
1398 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(name);
1399 const RunTimeClassInfo* record = nullptr;
1400 if (DynamicArchive::is_mapped()) {
1401 // Use the regenerated holder classes in the dynamic archive as they
1402 // have more methods than those in the base archive.
1403 if (LambdaFormInvokers::may_be_regenerated_class(name)) {
1404 record = dynamic_dict->lookup(name, hash, 0);
1405 if (record != nullptr) {
1406 return record;
1407 }
1408 }
1409 }
1410
1411 if (!AOTMetaspace::in_aot_cache_dynamic_region(name)) {
1412 // The names of all shared classes in the static dict must also be in the
1413 // static archive
1414 record = static_dict->lookup(name, hash, 0);
1415 }
1416
1417 if (record == nullptr && DynamicArchive::is_mapped()) {
1418 record = dynamic_dict->lookup(name, hash, 0);
1419 }
1420
1421 return record;
1422 }
1423
1424 InstanceKlass* SystemDictionaryShared::find_builtin_class(Symbol* name) {
1425 const RunTimeClassInfo* record = find_record(&_static_archive._builtin_dictionary,
1426 &_dynamic_archive._builtin_dictionary,
1427 name);
1428 if (record != nullptr) {
1429 assert(!record->klass()->is_hidden(), "hidden class cannot be looked up by name");
1430 DEBUG_ONLY(check_klass_after_loading(record->klass());)
1431 // We did not save the classfile data of the generated LambdaForm invoker classes,
1432 // so we cannot support CLFH for such classes.
1433 if (record->klass()->is_aot_generated_class() && JvmtiExport::should_post_class_file_load_hook()) {
1434 return nullptr;
1435 }
1436 return record->klass();
1437 } else {
1438 return nullptr;
1439 }
1440 }
1441
1442 void SystemDictionaryShared::update_shared_entry(InstanceKlass* k, int id) {
1443 assert(CDSConfig::is_dumping_static_archive(), "class ID is used only for static dump (from classlist)");
1444 DumpTimeClassInfo* info = get_info(k);
1445 info->_id = id;
1446 }
1447
1448 const char* SystemDictionaryShared::loader_type_for_shared_class(Klass* k) {
1449 assert(k != nullptr, "Sanity");
1450 assert(k->in_aot_cache(), "Must be");
1451 assert(k->is_instance_klass(), "Must be");
1452 InstanceKlass* ik = InstanceKlass::cast(k);
1453 if (ik->defined_by_boot_loader()) {
1454 return "boot_loader";
1455 } else if (ik->defined_by_platform_loader()) {
1456 return "platform_loader";
1457 } else if (ik->defined_by_app_loader()) {
1458 return "app_loader";
1459 } else if (ik->defined_by_other_loaders()) {
1460 return "unregistered_loader";
1461 } else {
1462 return "unknown loader";
1463 }
1464 }
1465
1466 void SystemDictionaryShared::get_all_archived_classes(bool is_static_archive, GrowableArray<Klass*>* classes) {
1467 get_archive(is_static_archive)->_builtin_dictionary.iterate([&] (const RunTimeClassInfo* record) {
1468 classes->append(record->klass());
1469 });
1470
1471 get_archive(is_static_archive)->_unregistered_dictionary.iterate([&] (const RunTimeClassInfo* record) {
1472 classes->append(record->klass());
1473 });
1474 }
1475
1476 class SharedDictionaryPrinter : StackObj {
1477 outputStream* _st;
1478 int _index;
1479 public:
1480 SharedDictionaryPrinter(outputStream* st) : _st(st), _index(0) {}
1481
1482 void do_value(const RunTimeClassInfo* record) {
1483 ResourceMark rm;
1484 _st->print_cr("%4d: %s %s", _index++, record->klass()->external_name(),
1485 SystemDictionaryShared::loader_type_for_shared_class(record->klass()));
1486 if (record->klass()->array_klasses() != nullptr) {
1487 record->klass()->array_klasses()->cds_print_value_on(_st);
1488 _st->cr();
1489 }
1490 }
1491 int index() const { return _index; }
1492 };
1493
1494 void SystemDictionaryShared::ArchiveInfo::print_on(const char* prefix,
1495 outputStream* st,
1496 bool is_static_archive) {
1497 st->print_cr("%sShared Dictionary", prefix);
1498 SharedDictionaryPrinter p(st);
1499 st->print_cr("%sShared Builtin Dictionary", prefix);
1500 _builtin_dictionary.iterate(&p);
1501 st->print_cr("%sShared Unregistered Dictionary", prefix);
1502 _unregistered_dictionary.iterate(&p);
1503 LambdaProxyClassDictionary::print_on(prefix, st, p.index(), is_static_archive);
1504 }
1505
1506 void SystemDictionaryShared::ArchiveInfo::print_table_statistics(const char* prefix,
1507 outputStream* st,
1508 bool is_static_archive) {
1509 st->print_cr("%sArchve Statistics", prefix);
1510 _builtin_dictionary.print_table_statistics(st, "Builtin Shared Dictionary");
1511 _unregistered_dictionary.print_table_statistics(st, "Unregistered Shared Dictionary");
1512 LambdaProxyClassDictionary::print_statistics(st, is_static_archive);
1513 }
1514
1515 void SystemDictionaryShared::print_shared_archive(outputStream* st, bool is_static) {
1516 if (CDSConfig::is_using_archive()) {
1517 if (is_static) {
1518 _static_archive.print_on("", st, true);
1519 } else {
1520 if (DynamicArchive::is_mapped()) {
1521 _dynamic_archive.print_on("Dynamic ", st, false);
1522 }
1523 }
1524 }
1525 }
1526
1527 void SystemDictionaryShared::print_on(outputStream* st) {
1528 print_shared_archive(st, true);
1529 print_shared_archive(st, false);
1530 }
1531
1532 void SystemDictionaryShared::print_table_statistics(outputStream* st) {
1533 if (CDSConfig::is_using_archive()) {
1534 _static_archive.print_table_statistics("Static ", st, true);
1535 if (DynamicArchive::is_mapped()) {
1536 _dynamic_archive.print_table_statistics("Dynamic ", st, false);
1537 }
1538 }
1539 }
1540
1541 bool SystemDictionaryShared::is_dumptime_table_empty() {
1542 assert_lock_strong(DumpTimeTable_lock);
1543 _dumptime_table->update_counts();
1544 if (_dumptime_table->count_of(true) == 0 && _dumptime_table->count_of(false) == 0){
1545 return true;
1546 }
1547 return false;
1548 }
1549
1550 void SystemDictionaryShared::create_loader_positive_lookup_cache(TRAPS) {
1551 GrowableArray<InstanceKlass*> shared_classes_list;
1552 {
1553 // With static dumping, we have only a single Java thread (see JVM_StartThread) so
1554 // no no other threads should be loading classes. Otherwise, the code below may miss some
1555 // classes that are loaded concurrently.
1556 assert(CDSConfig::is_dumping_static_archive(), "no other threads should be loading classes");
1557
1558 MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
1559 _dumptime_table->iterate_all_classes_in_builtin_loaders([&](InstanceKlass* k, DumpTimeClassInfo& info) {
1560 // FIXME -- this may not be correct before SystemDictionaryShared::finish_exclusion_checks()
1561 if (!k->is_hidden() && info.has_checked_exclusion() && !info.is_excluded()) {
1562 shared_classes_list.append(k);
1563 }
1564 }
1565 );
1566 }
1567
1568 InstanceKlass* ik = vmClasses::Class_klass();
1569 objArrayOop r = oopFactory::new_objArray(ik, shared_classes_list.length(), CHECK);
1570 objArrayHandle array_h(THREAD, r);
1571
1572 for (int i = 0; i < shared_classes_list.length(); i++) {
1573 oop mirror = shared_classes_list.at(i)->java_mirror();
1574 Handle mirror_h(THREAD, mirror);
1575 array_h->obj_at_put(i, mirror_h());
1576 }
1577
1578 TempNewSymbol method = SymbolTable::new_symbol("generatePositiveLookupCache");
1579 TempNewSymbol signature = SymbolTable::new_symbol("([Ljava/lang/Class;)V");
1580
1581 JavaCallArguments args(Handle(THREAD, SystemDictionary::java_system_loader()));
1582 args.push_oop(array_h);
1583 JavaValue result(T_VOID);
1584 JavaCalls::call_virtual(&result,
1585 vmClasses::jdk_internal_loader_ClassLoaders_AppClassLoader_klass(),
1586 method,
1587 signature,
1588 &args,
1589 CHECK);
1590
1591 if (HAS_PENDING_EXCEPTION) {
1592 Handle exc_handle(THREAD, PENDING_EXCEPTION);
1593 CLEAR_PENDING_EXCEPTION;
1594 ResourceMark rm(THREAD);
1595
1596 log_warning(cds)("Exception during AppClassLoader::generatePositiveLookupCache() call");
1597 LogStreamHandle(Debug, cds) log;
1598 if (log.is_enabled()) {
1599 java_lang_Throwable::print_stack_trace(exc_handle, &log);
1600 }
1601 return;
1602 }
1603 }