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