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