1 /*
2 * Copyright (c) 1997, 2024, 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 #include "precompiled.hpp"
26 #include "cds/cdsConfig.hpp"
27 #include "cds/heapShared.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/classLoadInfo.hpp"
35 #include "classfile/dictionary.hpp"
36 #include "classfile/javaClasses.inline.hpp"
37 #include "classfile/klassFactory.hpp"
38 #include "classfile/loaderConstraints.hpp"
39 #include "classfile/packageEntry.hpp"
40 #include "classfile/placeholders.hpp"
41 #include "classfile/protectionDomainCache.hpp"
42 #include "classfile/resolutionErrors.hpp"
43 #include "classfile/stringTable.hpp"
44 #include "classfile/symbolTable.hpp"
45 #include "classfile/systemDictionary.hpp"
46 #include "classfile/vmClasses.hpp"
47 #include "classfile/vmSymbols.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "interpreter/bootstrapInfo.hpp"
50 #include "jfr/jfrEvents.hpp"
51 #include "jvm.h"
52 #include "logging/log.hpp"
53 #include "logging/logStream.hpp"
54 #include "memory/metaspaceClosure.hpp"
55 #include "memory/oopFactory.hpp"
56 #include "memory/resourceArea.hpp"
57 #include "memory/universe.hpp"
58 #include "oops/access.inline.hpp"
59 #include "oops/instanceKlass.hpp"
60 #include "oops/klass.inline.hpp"
61 #include "oops/method.inline.hpp"
62 #include "oops/objArrayKlass.hpp"
63 #include "oops/objArrayOop.inline.hpp"
64 #include "oops/oop.inline.hpp"
65 #include "oops/oop.hpp"
66 #include "oops/oopHandle.hpp"
67 #include "oops/oopHandle.inline.hpp"
68 #include "oops/symbol.hpp"
69 #include "oops/typeArrayKlass.hpp"
70 #include "prims/jvmtiExport.hpp"
71 #include "prims/methodHandles.hpp"
72 #include "runtime/arguments.hpp"
73 #include "runtime/atomic.hpp"
74 #include "runtime/handles.inline.hpp"
75 #include "runtime/java.hpp"
76 #include "runtime/javaCalls.hpp"
77 #include "runtime/mutexLocker.hpp"
78 #include "runtime/sharedRuntime.hpp"
79 #include "runtime/signature.hpp"
80 #include "runtime/synchronizer.hpp"
81 #include "services/classLoadingService.hpp"
82 #include "services/diagnosticCommand.hpp"
83 #include "services/finalizerService.hpp"
84 #include "services/threadService.hpp"
85 #include "utilities/macros.hpp"
86 #include "utilities/utf8.hpp"
87 #if INCLUDE_CDS
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JFR
91 #include "jfr/jfr.hpp"
92 #endif
93
94 class InvokeMethodKey : public StackObj {
95 private:
96 Symbol* _symbol;
97 intptr_t _iid;
98
99 public:
100 InvokeMethodKey(Symbol* symbol, intptr_t iid) :
101 _symbol(symbol),
102 _iid(iid) {}
103
104 static bool key_comparison(InvokeMethodKey const &k1, InvokeMethodKey const &k2){
105 return k1._symbol == k2._symbol && k1._iid == k2._iid;
106 }
107
108 static unsigned int compute_hash(const InvokeMethodKey &k) {
109 Symbol* sym = k._symbol;
110 intptr_t iid = k._iid;
111 unsigned int hash = (unsigned int) sym -> identity_hash();
112 return (unsigned int) (hash ^ iid);
113 }
114
115 };
116
117 using InvokeMethodIntrinsicTable = ResourceHashtable<InvokeMethodKey, Method*, 139, AnyObj::C_HEAP, mtClass,
118 InvokeMethodKey::compute_hash, InvokeMethodKey::key_comparison>;
119 static InvokeMethodIntrinsicTable* _invoke_method_intrinsic_table;
120 using InvokeMethodTypeTable = ResourceHashtable<SymbolHandle, OopHandle, 139, AnyObj::C_HEAP, mtClass, SymbolHandle::compute_hash>;
121 static InvokeMethodTypeTable* _invoke_method_type_table;
122
123 OopHandle SystemDictionary::_java_system_loader;
124 OopHandle SystemDictionary::_java_platform_loader;
125
126 // ----------------------------------------------------------------------------
127 // Java-level SystemLoader and PlatformLoader
128 oop SystemDictionary::java_system_loader() {
129 return _java_system_loader.resolve();
130 }
131
132 oop SystemDictionary::java_platform_loader() {
133 return _java_platform_loader.resolve();
134 }
135
136 void SystemDictionary::compute_java_loaders(TRAPS) {
137 if (_java_system_loader.is_empty()) {
138 oop system_loader = get_system_class_loader_impl(CHECK);
139 _java_system_loader = OopHandle(Universe::vm_global(), system_loader);
140 } else {
141 // It must have been restored from the archived module graph
142 assert(CDSConfig::is_using_archive(), "must be");
143 assert(CDSConfig::is_using_full_module_graph(), "must be");
144 DEBUG_ONLY(
145 oop system_loader = get_system_class_loader_impl(CHECK);
146 assert(_java_system_loader.resolve() == system_loader, "must be");
147 )
148 }
149
150 if (_java_platform_loader.is_empty()) {
151 oop platform_loader = get_platform_class_loader_impl(CHECK);
152 _java_platform_loader = OopHandle(Universe::vm_global(), platform_loader);
153 } else {
154 // It must have been restored from the archived module graph
155 assert(CDSConfig::is_using_archive(), "must be");
156 assert(CDSConfig::is_using_full_module_graph(), "must be");
157 DEBUG_ONLY(
158 oop platform_loader = get_platform_class_loader_impl(CHECK);
159 assert(_java_platform_loader.resolve() == platform_loader, "must be");
160 )
161 }
162 }
163
164 oop SystemDictionary::get_system_class_loader_impl(TRAPS) {
165 JavaValue result(T_OBJECT);
166 InstanceKlass* class_loader_klass = vmClasses::ClassLoader_klass();
167 JavaCalls::call_static(&result,
168 class_loader_klass,
169 vmSymbols::getSystemClassLoader_name(),
170 vmSymbols::void_classloader_signature(),
171 CHECK_NULL);
172 return result.get_oop();
173 }
174
175 oop SystemDictionary::get_platform_class_loader_impl(TRAPS) {
176 JavaValue result(T_OBJECT);
177 InstanceKlass* class_loader_klass = vmClasses::ClassLoader_klass();
178 JavaCalls::call_static(&result,
179 class_loader_klass,
180 vmSymbols::getPlatformClassLoader_name(),
181 vmSymbols::void_classloader_signature(),
182 CHECK_NULL);
183 return result.get_oop();
184 }
185
186 // Helper function
187 inline ClassLoaderData* class_loader_data(Handle class_loader) {
188 return ClassLoaderData::class_loader_data(class_loader());
189 }
190
191 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
192 if (create_mirror_cld) {
193 // Add a new class loader data to the graph.
194 return ClassLoaderDataGraph::add(class_loader, true);
195 } else {
196 return (class_loader() == nullptr) ? ClassLoaderData::the_null_class_loader_data() :
197 ClassLoaderDataGraph::find_or_create(class_loader);
198 }
199 }
200
201 void SystemDictionary::set_system_loader(ClassLoaderData *cld) {
202 assert(_java_system_loader.is_empty(), "already set!");
203 _java_system_loader = cld->class_loader_handle();
204
205 }
206
207 void SystemDictionary::set_platform_loader(ClassLoaderData *cld) {
208 assert(_java_platform_loader.is_empty(), "already set!");
209 _java_platform_loader = cld->class_loader_handle();
210 }
211
212 // ----------------------------------------------------------------------------
213 // Parallel class loading check
214
215 static bool is_parallelCapable(Handle class_loader) {
216 if (class_loader.is_null()) return true;
217 return java_lang_ClassLoader::parallelCapable(class_loader());
218 }
219 // ----------------------------------------------------------------------------
220 // ParallelDefineClass flag does not apply to bootclass loader
221 static bool is_parallelDefine(Handle class_loader) {
222 if (class_loader.is_null()) return false;
223 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
224 return true;
225 }
226 return false;
227 }
228
229 // Returns true if the passed class loader is the builtin application class loader
230 // or a custom system class loader. A customer system class loader can be
231 // specified via -Djava.system.class.loader.
232 bool SystemDictionary::is_system_class_loader(oop class_loader) {
233 if (class_loader == nullptr) {
234 return false;
235 }
236 return (class_loader->klass() == vmClasses::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
237 class_loader == _java_system_loader.peek());
238 }
239
240 // Returns true if the passed class loader is the platform class loader.
241 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
242 if (class_loader == nullptr) {
243 return false;
244 }
245 return (class_loader->klass() == vmClasses::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
246 }
247
248 Handle SystemDictionary::get_loader_lock_or_null(Handle class_loader) {
249 // If class_loader is null or parallelCapable, the JVM doesn't acquire a lock while loading.
250 if (is_parallelCapable(class_loader)) {
251 return Handle();
252 } else {
253 return class_loader;
254 }
255 }
256
257 // ----------------------------------------------------------------------------
258 // Resolving of classes
259
260 Symbol* SystemDictionary::class_name_symbol(const char* name, Symbol* exception, TRAPS) {
261 if (name == nullptr) {
262 THROW_MSG_NULL(exception, "No class name given");
263 }
264 size_t name_len = strlen(name);
265 if (name_len > static_cast<size_t>(Symbol::max_length())) {
266 // It's impossible to create this class; the name cannot fit
267 // into the constant pool. If necessary report an abridged name
268 // in the exception message.
269 if (name_len > static_cast<size_t>(MaxStringPrintSize)) {
270 Exceptions::fthrow(THREAD_AND_LOCATION, exception,
271 "Class name exceeds maximum length of %d: %.*s ... (%zu characters omitted) ... %.*s",
272 Symbol::max_length(),
273 MaxStringPrintSize / 2,
274 name,
275 name_len - 2 * (MaxStringPrintSize / 2), // allows for odd value
276 MaxStringPrintSize / 2,
277 name + name_len - MaxStringPrintSize / 2);
278 }
279 else {
280 Exceptions::fthrow(THREAD_AND_LOCATION, exception,
281 "Class name exceeds maximum length of %d: %s",
282 Symbol::max_length(),
283 name);
284 }
285 return nullptr;
286 }
287 // Callers should ensure that the name is never an illegal UTF8 string.
288 assert(UTF8::is_legal_utf8((const unsigned char*)name, name_len, false),
289 "Class name is not a valid utf8 string.");
290
291 // Make a new symbol for the class name.
292 return SymbolTable::new_symbol(name);
293 }
294
295 #ifdef ASSERT
296 // Used to verify that class loading succeeded in adding k to the dictionary.
297 static void verify_dictionary_entry(Symbol* class_name, InstanceKlass* k) {
298 MutexLocker mu(SystemDictionary_lock);
299 ClassLoaderData* loader_data = k->class_loader_data();
300 Dictionary* dictionary = loader_data->dictionary();
301 assert(class_name == k->name(), "Must be the same");
302 InstanceKlass* kk = dictionary->find_class(JavaThread::current(), class_name);
303 assert(kk == k, "should be present in dictionary");
304 }
305 #endif
306
307 static void handle_resolution_exception(Symbol* class_name, bool throw_error, TRAPS) {
308 if (HAS_PENDING_EXCEPTION) {
309 // If we have a pending exception we forward it to the caller, unless throw_error is true,
310 // in which case we have to check whether the pending exception is a ClassNotFoundException,
311 // and convert it to a NoClassDefFoundError and chain the original ClassNotFoundException.
312 if (throw_error && PENDING_EXCEPTION->is_a(vmClasses::ClassNotFoundException_klass())) {
313 ResourceMark rm(THREAD);
314 Handle e(THREAD, PENDING_EXCEPTION);
315 CLEAR_PENDING_EXCEPTION;
316 THROW_MSG_CAUSE(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
317 } else {
318 return; // the caller will throw the incoming exception
319 }
320 }
321 // If the class is not found, ie, caller has checked that klass is null, throw the appropriate
322 // error or exception depending on the value of throw_error.
323 ResourceMark rm(THREAD);
324 if (throw_error) {
325 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
326 } else {
327 THROW_MSG(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
328 }
329 }
330
331 // Forwards to resolve_or_null
332
333 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain,
334 bool throw_error, TRAPS) {
335 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
336 // Check for pending exception or null klass, and throw exception
337 if (HAS_PENDING_EXCEPTION || klass == nullptr) {
338 handle_resolution_exception(class_name, throw_error, CHECK_NULL);
339 }
340 return klass;
341 }
342
343 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
344
345 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
346 if (Signature::is_array(class_name)) {
347 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
348 } else {
349 assert(class_name != nullptr && !Signature::is_array(class_name), "must be");
350 if (Signature::has_envelope(class_name)) {
351 ResourceMark rm(THREAD);
352 // Ignore wrapping L and ;.
353 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
354 class_name->utf8_length() - 2);
355 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
356 } else {
357 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
358 }
359 }
360 }
361
362 // Forwards to resolve_instance_class_or_null
363
364 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
365 Handle class_loader,
366 Handle protection_domain,
367 TRAPS) {
368 assert(Signature::is_array(class_name), "must be array");
369 ResourceMark rm(THREAD);
370 SignatureStream ss(class_name, false);
371 int ndims = ss.skip_array_prefix(); // skip all '['s
372 Klass* k = nullptr;
373 BasicType t = ss.type();
374 if (ss.has_envelope()) {
375 Symbol* obj_class = ss.as_symbol();
376 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
377 class_loader,
378 protection_domain,
379 CHECK_NULL);
380 if (k != nullptr) {
381 k = k->array_klass(ndims, CHECK_NULL);
382 }
383 } else {
384 k = Universe::typeArrayKlass(t);
385 k = k->array_klass(ndims, CHECK_NULL);
386 }
387 return k;
388 }
389
390 static inline void log_circularity_error(Symbol* name, PlaceholderEntry* probe) {
391 LogTarget(Debug, class, load, placeholders) lt;
392 if (lt.is_enabled()) {
393 ResourceMark rm;
394 LogStream ls(lt);
395 ls.print("ClassCircularityError detected for placeholder entry %s", name->as_C_string());
396 probe->print_on(&ls);
397 ls.cr();
398 }
399 }
400
401 // Must be called for any superclass or superinterface resolution
402 // during class definition to allow class circularity checking
403 // superinterface callers:
404 // parse_interfaces - from defineClass
405 // superclass callers:
406 // ClassFileParser - from defineClass
407 // load_shared_class - while loading a class from shared archive
408 // resolve_instance_class_or_null:
409 // via: handle_parallel_super_load
410 // when resolving a class that has an existing placeholder with
411 // a saved superclass [i.e. a defineClass is currently in progress]
412 // If another thread is trying to resolve the class, it must do
413 // superclass checks on its own thread to catch class circularity and
414 // to avoid deadlock.
415 //
416 // resolve_with_circularity_detection adds a DETECT_CIRCULARITY placeholder to the placeholder table before calling
417 // resolve_instance_class_or_null. ClassCircularityError is detected when a DETECT_CIRCULARITY or LOAD_INSTANCE
418 // placeholder for the same thread, class, classloader is found.
419 // This can be seen with logging option: -Xlog:class+load+placeholders=debug.
420 //
421 InstanceKlass* SystemDictionary::resolve_with_circularity_detection(Symbol* class_name,
422 Symbol* next_name,
423 Handle class_loader,
424 Handle protection_domain,
425 bool is_superclass,
426 TRAPS) {
427
428 assert(next_name != nullptr, "null superclass for resolving");
429 assert(!Signature::is_array(next_name), "invalid superclass name");
430 #if INCLUDE_CDS
431 if (CDSConfig::is_dumping_static_archive()) {
432 // Special processing for handling UNREGISTERED shared classes.
433 InstanceKlass* k = SystemDictionaryShared::lookup_super_for_unregistered_class(class_name,
434 next_name, is_superclass);
435 if (k) {
436 return k;
437 }
438 }
439 #endif // INCLUDE_CDS
440
441 // If class_name is already loaded, just return the superclass or superinterface.
442 // Make sure there's a placeholder for the class_name before resolving.
443 // This is used as a claim that this thread is currently loading superclass/classloader
444 // and for ClassCircularity checks.
445
446 ClassLoaderData* loader_data = class_loader_data(class_loader);
447 Dictionary* dictionary = loader_data->dictionary();
448
449 // can't throw error holding a lock
450 bool throw_circularity_error = false;
451 {
452 MutexLocker mu(THREAD, SystemDictionary_lock);
453 InstanceKlass* klassk = dictionary->find_class(THREAD, class_name);
454 InstanceKlass* quicksuperk;
455 // To support parallel loading: if class is done loading, just return the superclass
456 // if the next_name matches class->super()->name() and if the class loaders match.
457 if (klassk != nullptr && is_superclass &&
458 ((quicksuperk = klassk->java_super()) != nullptr) &&
459 ((quicksuperk->name() == next_name) &&
460 (quicksuperk->class_loader() == class_loader()))) {
461 return quicksuperk;
462 } else {
463 // Must check ClassCircularity before checking if superclass is already loaded.
464 PlaceholderEntry* probe = PlaceholderTable::get_entry(class_name, loader_data);
465 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::DETECT_CIRCULARITY)) {
466 log_circularity_error(class_name, probe);
467 throw_circularity_error = true;
468 }
469 }
470
471 if (!throw_circularity_error) {
472 // Be careful not to exit resolve_with_circularity_detection without removing this placeholder.
473 PlaceholderEntry* newprobe = PlaceholderTable::find_and_add(class_name,
474 loader_data,
475 PlaceholderTable::DETECT_CIRCULARITY,
476 next_name, THREAD);
477 }
478 }
479
480 if (throw_circularity_error) {
481 ResourceMark rm(THREAD);
482 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), class_name->as_C_string());
483 }
484
485 // Resolve the superclass or superinterface, check results on return
486 InstanceKlass* superk =
487 SystemDictionary::resolve_instance_class_or_null(next_name,
488 class_loader,
489 protection_domain,
490 THREAD);
491
492 // Clean up placeholder entry.
493 {
494 MutexLocker mu(THREAD, SystemDictionary_lock);
495 PlaceholderTable::find_and_remove(class_name, loader_data, PlaceholderTable::DETECT_CIRCULARITY, THREAD);
496 SystemDictionary_lock->notify_all();
497 }
498
499 // Check for pending exception or null superk, and throw exception
500 if (HAS_PENDING_EXCEPTION || superk == nullptr) {
501 handle_resolution_exception(next_name, true, CHECK_NULL);
502 }
503
504 return superk;
505 }
506
507 // If the class in is in the placeholder table, class loading is in progress.
508 // For cases where the application changes threads to load classes, it
509 // is critical to ClassCircularity detection that we try loading
510 // the superclass on the new thread internally, so we do parallel
511 // superclass loading here. This avoids deadlock for ClassCircularity
512 // detection for parallelCapable class loaders that lock on a per-class lock.
513 static void handle_parallel_super_load(Symbol* name,
514 Symbol* superclassname,
515 Handle class_loader,
516 Handle protection_domain, TRAPS) {
517
518 // The result superk is not used; resolve_with_circularity_detection is called for circularity check only.
519 // This passes true to is_superclass even though it might not be the super class in order to perform the
520 // optimization anyway.
521 Klass* superk = SystemDictionary::resolve_with_circularity_detection(name,
522 superclassname,
523 class_loader,
524 protection_domain,
525 true,
526 CHECK);
527 }
528
529 // Bootstrap and non-parallel capable class loaders use the LOAD_INSTANCE placeholder to
530 // wait for parallel class loading and/or to check for circularity error for Xcomp when loading.
531 static bool needs_load_placeholder(Handle class_loader) {
532 return class_loader.is_null() || !is_parallelCapable(class_loader);
533 }
534
535 // Check for other threads loading this class either to throw CCE or wait in the case of the boot loader.
536 static InstanceKlass* handle_parallel_loading(JavaThread* current,
537 Symbol* name,
538 ClassLoaderData* loader_data,
539 bool must_wait_for_class_loading,
540 bool* throw_circularity_error) {
541 PlaceholderEntry* oldprobe = PlaceholderTable::get_entry(name, loader_data);
542 if (oldprobe != nullptr) {
543 // -Xcomp calls load_signature_classes which might result in loading
544 // a class that's already in the process of loading, so we detect CCE here also.
545 // Only need check_seen_thread once, not on each loop
546 if (oldprobe->check_seen_thread(current, PlaceholderTable::LOAD_INSTANCE)) {
547 log_circularity_error(name, oldprobe);
548 *throw_circularity_error = true;
549 return nullptr;
550 } else if (must_wait_for_class_loading) {
551 // Wait until the first thread has finished loading this class. Also wait until all the
552 // threads trying to load its superclass have removed their placeholders.
553 while (oldprobe != nullptr &&
554 (oldprobe->instance_load_in_progress() || oldprobe->circularity_detection_in_progress())) {
555
556 // LOAD_INSTANCE placeholders are used to implement parallel capable class loading
557 // for the bootclass loader.
558 SystemDictionary_lock->wait();
559
560 // Check if classloading completed while we were waiting
561 InstanceKlass* check = loader_data->dictionary()->find_class(current, name);
562 if (check != nullptr) {
563 // Klass is already loaded, so just return it
564 return check;
565 }
566 // check if other thread failed to load and cleaned up
567 oldprobe = PlaceholderTable::get_entry(name, loader_data);
568 }
569 }
570 }
571 return nullptr;
572 }
573
574 void SystemDictionary::post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
575 assert(event != nullptr, "invariant");
576 assert(k != nullptr, "invariant");
577 event->set_loadedClass(k);
578 event->set_definingClassLoader(k->class_loader_data());
579 event->set_initiatingClassLoader(init_cld);
580 event->commit();
581 }
582
583 // SystemDictionary::resolve_instance_class_or_null is the main function for class name resolution.
584 // After checking if the InstanceKlass already exists, it checks for ClassCircularityError and
585 // whether the thread must wait for loading in parallel. It eventually calls load_instance_class,
586 // which will load the class via the bootstrap loader or call ClassLoader.loadClass().
587 // This can return null, an exception or an InstanceKlass.
588 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
589 Handle class_loader,
590 Handle protection_domain,
591 TRAPS) {
592 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
593 DEBUG_ONLY(ResourceMark rm(THREAD));
594 assert(name != nullptr && !Signature::is_array(name) &&
595 !Signature::has_envelope(name), "invalid class name: %s", name == nullptr ? "nullptr" : name->as_C_string());
596
597 EventClassLoad class_load_start_event;
598
599 HandleMark hm(THREAD);
600
601 // Fix for 4474172; see evaluation for more details
602 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
603 ClassLoaderData* loader_data = register_loader(class_loader);
604 Dictionary* dictionary = loader_data->dictionary();
605
606 // Do lookup to see if class already exists and the protection domain
607 // has the right access.
608 // This call uses find which checks protection domain already matches
609 // All subsequent calls use find_class, and set loaded_class so that
610 // before we return a result, we call out to java to check for valid protection domain.
611 InstanceKlass* probe = dictionary->find(THREAD, name, protection_domain);
612 if (probe != nullptr) return probe;
613
614 // Non-bootstrap class loaders will call out to class loader and
615 // define via jvm/jni_DefineClass which will acquire the
616 // class loader object lock to protect against multiple threads
617 // defining the class in parallel by accident.
618 // This lock must be acquired here so the waiter will find
619 // any successful result in the SystemDictionary and not attempt
620 // the define.
621 // ParallelCapable class loaders and the bootstrap classloader
622 // do not acquire lock here.
623 Handle lockObject = get_loader_lock_or_null(class_loader);
624 ObjectLocker ol(lockObject, THREAD);
625
626 bool circularity_detection_in_progress = false;
627 InstanceKlass* loaded_class = nullptr;
628 SymbolHandle superclassname; // Keep alive while loading in parallel thread.
629
630 guarantee(THREAD->can_call_java(),
631 "can not load classes with compiler thread: class=%s, classloader=%s",
632 name->as_C_string(),
633 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
634
635 // Check again (after locking) if the class already exists in SystemDictionary
636 {
637 MutexLocker mu(THREAD, SystemDictionary_lock);
638 InstanceKlass* check = dictionary->find_class(THREAD, name);
639 if (check != nullptr) {
640 // InstanceKlass is already loaded, but we still need to check protection domain below.
641 loaded_class = check;
642 } else {
643 PlaceholderEntry* placeholder = PlaceholderTable::get_entry(name, loader_data);
644 if (placeholder != nullptr && placeholder->circularity_detection_in_progress()) {
645 circularity_detection_in_progress = true;
646 superclassname = placeholder->next_klass_name();
647 assert(superclassname != nullptr, "superclass has to have a name");
648 }
649 }
650 }
651
652 // If the class is in the placeholder table with super_class set,
653 // handle superclass loading in progress.
654 if (circularity_detection_in_progress) {
655 handle_parallel_super_load(name, superclassname,
656 class_loader,
657 protection_domain,
658 CHECK_NULL);
659 }
660
661 bool throw_circularity_error = false;
662 if (loaded_class == nullptr) {
663 bool load_placeholder_added = false;
664
665 // Add placeholder entry to record loading instance class
666 // case 1. Bootstrap classloader
667 // This classloader supports parallelism at the classloader level
668 // but only allows a single thread to load a class/classloader pair.
669 // The LOAD_INSTANCE placeholder is the mechanism for mutual exclusion.
670 // case 2. parallelCapable user level classloaders
671 // These class loaders lock a per-class object lock when ClassLoader.loadClass()
672 // is called. A LOAD_INSTANCE placeholder isn't used for mutual exclusion.
673 // case 3. traditional classloaders that rely on the classloader object lock
674 // There should be no need for need for LOAD_INSTANCE for mutual exclusion,
675 // except the LOAD_INSTANCE placeholder is used to detect CCE for -Xcomp.
676 // TODO: should also be used to detect CCE for parallel capable class loaders but it's not.
677 {
678 MutexLocker mu(THREAD, SystemDictionary_lock);
679 if (needs_load_placeholder(class_loader)) {
680 loaded_class = handle_parallel_loading(THREAD,
681 name,
682 loader_data,
683 class_loader.is_null(),
684 &throw_circularity_error);
685 }
686
687 // Recheck if the class has been loaded for all class loader cases and
688 // add a LOAD_INSTANCE placeholder while holding the SystemDictionary_lock.
689 if (!throw_circularity_error && loaded_class == nullptr) {
690 InstanceKlass* check = dictionary->find_class(THREAD, name);
691 if (check != nullptr) {
692 loaded_class = check;
693 } else if (needs_load_placeholder(class_loader)) {
694 // Add the LOAD_INSTANCE token. Threads will wait on loading to complete for this thread.
695 PlaceholderEntry* newprobe = PlaceholderTable::find_and_add(name, loader_data,
696 PlaceholderTable::LOAD_INSTANCE,
697 nullptr,
698 THREAD);
699 load_placeholder_added = true;
700 }
701 }
702 }
703
704 // Must throw error outside of owning lock
705 if (throw_circularity_error) {
706 assert(!HAS_PENDING_EXCEPTION && !load_placeholder_added, "circularity error cleanup");
707 ResourceMark rm(THREAD);
708 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
709 }
710
711 // Be careful when modifying this code: once you have run
712 // PlaceholderTable::find_and_add(PlaceholderTable::LOAD_INSTANCE),
713 // you need to find_and_remove it before returning.
714 // So be careful to not exit with a CHECK_ macro between these calls.
715
716 if (loaded_class == nullptr) {
717 // Do actual loading
718 loaded_class = load_instance_class(name, class_loader, THREAD);
719 }
720
721 if (load_placeholder_added) {
722 // clean up placeholder entries for LOAD_INSTANCE success or error
723 // This brackets the SystemDictionary updates for both defining
724 // and initiating loaders
725 MutexLocker mu(THREAD, SystemDictionary_lock);
726 PlaceholderTable::find_and_remove(name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
727 SystemDictionary_lock->notify_all();
728 }
729 }
730
731 if (HAS_PENDING_EXCEPTION || loaded_class == nullptr) {
732 return nullptr;
733 }
734
735 if (class_load_start_event.should_commit()) {
736 post_class_load_event(&class_load_start_event, loaded_class, loader_data);
737 }
738
739 // Make sure we have the right class in the dictionary
740 DEBUG_ONLY(verify_dictionary_entry(name, loaded_class));
741
742 if (protection_domain() != nullptr) {
743 // A SecurityManager (if installed) may prevent this protection_domain from accessing loaded_class
744 // by throwing a SecurityException.
745 dictionary->check_package_access(loaded_class, class_loader, protection_domain, CHECK_NULL);
746 }
747
748 return loaded_class;
749 }
750
751
752 // This routine does not lock the system dictionary.
753 //
754 // Since readers don't hold a lock, we must make sure that system
755 // dictionary entries are added to in a safe way (all links must
756 // be updated in an MT-safe manner). All entries are removed during class
757 // unloading, when this class loader is no longer referenced.
758 //
759 // Callers should be aware that an entry could be added just after
760 // Dictionary is read here, so the caller will not see
761 // the new entry.
762
763 InstanceKlass* SystemDictionary::find_instance_klass(Thread* current,
764 Symbol* class_name,
765 Handle class_loader,
766 Handle protection_domain) {
767
768 // The result of this call should be consistent with the result
769 // of the call to resolve_instance_class_or_null().
770 // See evaluation 6790209 and 4474172 for more details.
771 oop class_loader_oop = java_lang_ClassLoader::non_reflection_class_loader(class_loader());
772 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader_oop);
773
774 if (loader_data == nullptr) {
775 // If the ClassLoaderData has not been setup,
776 // then the class loader has no entries in the dictionary.
777 return nullptr;
778 }
779
780 Dictionary* dictionary = loader_data->dictionary();
781 return dictionary->find(current, class_name, protection_domain);
782 }
783
784 // Look for a loaded instance or array klass by name. Do not do any loading.
785 // return null in case of error.
786 Klass* SystemDictionary::find_instance_or_array_klass(Thread* current,
787 Symbol* class_name,
788 Handle class_loader,
789 Handle protection_domain) {
790 Klass* k = nullptr;
791 assert(class_name != nullptr, "class name must be non nullptr");
792
793 if (Signature::is_array(class_name)) {
794 // The name refers to an array. Parse the name.
795 // dimension and object_key in FieldArrayInfo are assigned as a
796 // side-effect of this call
797 SignatureStream ss(class_name, false);
798 int ndims = ss.skip_array_prefix(); // skip all '['s
799 BasicType t = ss.type();
800 if (t != T_OBJECT) {
801 k = Universe::typeArrayKlass(t);
802 } else {
803 k = SystemDictionary::find_instance_klass(current, ss.as_symbol(), class_loader, protection_domain);
804 }
805 if (k != nullptr) {
806 k = k->array_klass_or_null(ndims);
807 }
808 } else {
809 k = find_instance_klass(current, class_name, class_loader, protection_domain);
810 }
811 return k;
812 }
813
814 // Note: this method is much like resolve_class_from_stream, but
815 // does not publish the classes in the SystemDictionary.
816 // Handles Lookup.defineClass hidden.
817 InstanceKlass* SystemDictionary::resolve_hidden_class_from_stream(
818 ClassFileStream* st,
819 Symbol* class_name,
820 Handle class_loader,
821 const ClassLoadInfo& cl_info,
822 TRAPS) {
823
824 EventClassLoad class_load_start_event;
825 ClassLoaderData* loader_data;
826
827 // - for hidden classes that are not strong: create a new CLD that has a class holder and
828 // whose loader is the Lookup class's loader.
829 // - for hidden class: add the class to the Lookup class's loader's CLD.
830 assert (cl_info.is_hidden(), "only used for hidden classes");
831 bool create_mirror_cld = !cl_info.is_strong_hidden();
832 loader_data = register_loader(class_loader, create_mirror_cld);
833
834 assert(st != nullptr, "invariant");
835 assert(st->need_verify(), "invariant");
836
837 // Parse stream and create a klass.
838 InstanceKlass* k = KlassFactory::create_from_stream(st,
839 class_name,
840 loader_data,
841 cl_info,
842 CHECK_NULL);
843 assert(k != nullptr, "no klass created");
844
845 // Hidden classes that are not strong must update ClassLoaderData holder
846 // so that they can be unloaded when the mirror is no longer referenced.
847 if (!cl_info.is_strong_hidden()) {
848 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
849 }
850
851 // Add to class hierarchy, and do possible deoptimizations.
852 k->add_to_hierarchy(THREAD);
853 // But, do not add to dictionary.
854
855 k->link_class(CHECK_NULL);
856
857 // notify jvmti
858 if (JvmtiExport::should_post_class_load()) {
859 JvmtiExport::post_class_load(THREAD, k);
860 }
861 if (class_load_start_event.should_commit()) {
862 post_class_load_event(&class_load_start_event, k, loader_data);
863 }
864
865 return k;
866 }
867
868 // Add a klass to the system from a stream (called by jni_DefineClass and
869 // JVM_DefineClass).
870 // Note: class_name can be null. In that case we do not know the name of
871 // the class until we have parsed the stream.
872 // This function either returns an InstanceKlass or throws an exception. It does
873 // not return null without a pending exception.
874 InstanceKlass* SystemDictionary::resolve_class_from_stream(
875 ClassFileStream* st,
876 Symbol* class_name,
877 Handle class_loader,
878 const ClassLoadInfo& cl_info,
879 TRAPS) {
880
881 HandleMark hm(THREAD);
882
883 ClassLoaderData* loader_data = register_loader(class_loader);
884
885 // Classloaders that support parallelism, e.g. bootstrap classloader,
886 // do not acquire lock here
887 Handle lockObject = get_loader_lock_or_null(class_loader);
888 ObjectLocker ol(lockObject, THREAD);
889
890 // Parse the stream and create a klass.
891 // Note that we do this even though this klass might
892 // already be present in the SystemDictionary, otherwise we would not
893 // throw potential ClassFormatErrors.
894 InstanceKlass* k = nullptr;
895
896 #if INCLUDE_CDS
897 if (!CDSConfig::is_dumping_static_archive()) {
898 k = SystemDictionaryShared::lookup_from_stream(class_name,
899 class_loader,
900 cl_info.protection_domain(),
901 st,
902 CHECK_NULL);
903 }
904 #endif
905
906 if (k == nullptr) {
907 k = KlassFactory::create_from_stream(st, class_name, loader_data, cl_info, CHECK_NULL);
908 }
909
910 assert(k != nullptr, "no klass created");
911 Symbol* h_name = k->name();
912 assert(class_name == nullptr || class_name == h_name, "name mismatch");
913
914 // Add class just loaded
915 // If a class loader supports parallel classloading, handle parallel define requests.
916 // find_or_define_instance_class may return a different InstanceKlass,
917 // in which case the old k would be deallocated
918 if (is_parallelCapable(class_loader)) {
919 k = find_or_define_instance_class(h_name, class_loader, k, CHECK_NULL);
920 } else {
921 define_instance_class(k, class_loader, THREAD);
922
923 // If defining the class throws an exception register 'k' for cleanup.
924 if (HAS_PENDING_EXCEPTION) {
925 assert(k != nullptr, "Must have an instance klass here!");
926 loader_data->add_to_deallocate_list(k);
927 return nullptr;
928 }
929 }
930
931 // Make sure we have an entry in the SystemDictionary on success
932 DEBUG_ONLY(verify_dictionary_entry(h_name, k));
933
934 return k;
935 }
936
937 InstanceKlass* SystemDictionary::resolve_from_stream(ClassFileStream* st,
938 Symbol* class_name,
939 Handle class_loader,
940 const ClassLoadInfo& cl_info,
941 TRAPS) {
942 if (cl_info.is_hidden()) {
943 return resolve_hidden_class_from_stream(st, class_name, class_loader, cl_info, CHECK_NULL);
944 } else {
945 return resolve_class_from_stream(st, class_name, class_loader, cl_info, CHECK_NULL);
946 }
947 }
948
949
950 #if INCLUDE_CDS
951 // Check if a shared class can be loaded by the specific classloader.
952 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
953 InstanceKlass* ik,
954 PackageEntry* pkg_entry,
955 Handle class_loader) {
956 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
957 "Cannot use sharing if java.base is patched");
958
959 // (1) Check if we are loading into the same loader as in dump time.
960
961 if (ik->is_shared_boot_class()) {
962 if (class_loader() != nullptr) {
963 return false;
964 }
965 } else if (ik->is_shared_platform_class()) {
966 if (class_loader() != java_platform_loader()) {
967 return false;
968 }
969 } else if (ik->is_shared_app_class()) {
970 if (class_loader() != java_system_loader()) {
971 return false;
972 }
973 } else {
974 // ik was loaded by a custom loader during dump time
975 if (class_loader_data(class_loader)->is_builtin_class_loader_data()) {
976 return false;
977 } else {
978 return true;
979 }
980 }
981
982 // (2) Check if we are loading into the same module from the same location as in dump time.
983
984 if (CDSConfig::is_using_optimized_module_handling()) {
985 // Class visibility has not changed between dump time and run time, so a class
986 // that was visible (and thus archived) during dump time is always visible during runtime.
987 assert(SystemDictionary::is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader),
988 "visibility cannot change between dump time and runtime");
989 return true;
990 }
991 return is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader);
992 }
993
994 bool SystemDictionary::is_shared_class_visible_impl(Symbol* class_name,
995 InstanceKlass* ik,
996 PackageEntry* pkg_entry,
997 Handle class_loader) {
998 int scp_index = ik->shared_classpath_index();
999 assert(!ik->is_shared_unregistered_class(), "this function should be called for built-in classes only");
1000 assert(scp_index >= 0, "must be");
1001 SharedClassPathEntry* scp_entry = FileMapInfo::shared_path(scp_index);
1002 if (!Universe::is_module_initialized()) {
1003 assert(scp_entry != nullptr, "must be");
1004 // At this point, no modules have been defined yet. KlassSubGraphInfo::check_allowed_klass()
1005 // has restricted the classes can be loaded at this step to be only:
1006 // [1] scp_entry->is_modules_image(): classes in java.base, or,
1007 // [2] HeapShared::is_a_test_class_in_unnamed_module(ik): classes in bootstrap/unnamed module
1008 assert(scp_entry->is_modules_image() || HeapShared::is_a_test_class_in_unnamed_module(ik),
1009 "only these classes can be loaded before the module system is initialized");
1010 assert(class_loader.is_null(), "sanity");
1011 return true;
1012 }
1013
1014 if (pkg_entry == nullptr) {
1015 // We might have looked up pkg_entry before the module system was initialized.
1016 // Need to reload it now.
1017 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1018 if (pkg_name != nullptr) {
1019 pkg_entry = class_loader_data(class_loader)->packages()->lookup_only(pkg_name);
1020 }
1021 }
1022
1023 ModuleEntry* mod_entry = (pkg_entry == nullptr) ? nullptr : pkg_entry->module();
1024 bool should_be_in_named_module = (mod_entry != nullptr && mod_entry->is_named());
1025 bool was_archived_from_named_module = scp_entry->in_named_module();
1026 bool visible;
1027
1028 if (was_archived_from_named_module) {
1029 if (should_be_in_named_module) {
1030 // Is the module loaded from the same location as during dump time?
1031 visible = mod_entry->shared_path_index() == scp_index;
1032 if (visible) {
1033 assert(!mod_entry->is_patched(), "cannot load archived classes for patched module");
1034 }
1035 } else {
1036 // During dump time, this class was in a named module, but at run time, this class should be
1037 // in an unnamed module.
1038 visible = false;
1039 }
1040 } else {
1041 if (should_be_in_named_module) {
1042 // During dump time, this class was in an unnamed, but at run time, this class should be
1043 // in a named module.
1044 visible = false;
1045 } else {
1046 visible = true;
1047 }
1048 }
1049
1050 return visible;
1051 }
1052
1053 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* klass, InstanceKlass* super_type,
1054 Handle class_loader, Handle protection_domain,
1055 bool is_superclass, TRAPS) {
1056 assert(super_type->is_shared(), "must be");
1057
1058 // Quick check if the super type has been already loaded.
1059 // + Don't do it for unregistered classes -- they can be unloaded so
1060 // super_type->class_loader_data() could be stale.
1061 // + Don't check if loader data is null, ie. the super_type isn't fully loaded.
1062 if (!super_type->is_shared_unregistered_class() && super_type->class_loader_data() != nullptr) {
1063 // Check if the superclass is loaded by the current class_loader
1064 Symbol* name = super_type->name();
1065 InstanceKlass* check = find_instance_klass(THREAD, name, class_loader, protection_domain);
1066 if (check == super_type) {
1067 return true;
1068 }
1069 }
1070
1071 Klass *found = resolve_with_circularity_detection(klass->name(), super_type->name(),
1072 class_loader, protection_domain, is_superclass, CHECK_false);
1073 if (found == super_type) {
1074 return true;
1075 } else {
1076 // The dynamically resolved super type is not the same as the one we used during dump time,
1077 // so we cannot use the class.
1078 return false;
1079 }
1080 }
1081
1082 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1083 Handle protection_domain, TRAPS) {
1084 // Check the superclass and interfaces. They must be the same
1085 // as in dump time, because the layout of <ik> depends on
1086 // the specific layout of ik->super() and ik->local_interfaces().
1087 //
1088 // If unexpected superclass or interfaces are found, we cannot
1089 // load <ik> from the shared archive.
1090
1091 if (ik->super() != nullptr) {
1092 bool check_super = check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1093 class_loader, protection_domain, true,
1094 CHECK_false);
1095 if (!check_super) {
1096 return false;
1097 }
1098 }
1099
1100 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1101 int num_interfaces = interfaces->length();
1102 for (int index = 0; index < num_interfaces; index++) {
1103 bool check_interface = check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false,
1104 CHECK_false);
1105 if (!check_interface) {
1106 return false;
1107 }
1108 }
1109
1110 return true;
1111 }
1112
1113 InstanceKlass* SystemDictionary::load_shared_lambda_proxy_class(InstanceKlass* ik,
1114 Handle class_loader,
1115 Handle protection_domain,
1116 PackageEntry* pkg_entry,
1117 TRAPS) {
1118 InstanceKlass* shared_nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1119 assert(shared_nest_host->is_shared(), "nest host must be in CDS archive");
1120 Symbol* cn = shared_nest_host->name();
1121 Klass *s = resolve_or_fail(cn, class_loader, protection_domain, true, CHECK_NULL);
1122 if (s != shared_nest_host) {
1123 // The dynamically resolved nest_host is not the same as the one we used during dump time,
1124 // so we cannot use ik.
1125 return nullptr;
1126 } else {
1127 assert(s->is_shared(), "must be");
1128 }
1129
1130 InstanceKlass* loaded_ik = load_shared_class(ik, class_loader, protection_domain, nullptr, pkg_entry, CHECK_NULL);
1131
1132 if (loaded_ik != nullptr) {
1133 assert(shared_nest_host->is_same_class_package(ik),
1134 "lambda proxy class and its nest host must be in the same package");
1135 // The lambda proxy class and its nest host have the same class loader and class loader data,
1136 // as verified in SystemDictionaryShared::add_lambda_proxy_class()
1137 assert(shared_nest_host->class_loader() == class_loader(), "mismatched class loader");
1138 assert(shared_nest_host->class_loader_data() == class_loader_data(class_loader), "mismatched class loader data");
1139 ik->set_nest_host(shared_nest_host);
1140 }
1141
1142 return loaded_ik;
1143 }
1144
1145 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1146 Handle class_loader,
1147 Handle protection_domain,
1148 const ClassFileStream *cfs,
1149 PackageEntry* pkg_entry,
1150 TRAPS) {
1151 assert(ik != nullptr, "sanity");
1152 assert(!ik->is_unshareable_info_restored(), "shared class can be restored only once");
1153 assert(Atomic::add(&ik->_shared_class_load_count, 1) == 1, "shared class loaded more than once");
1154 Symbol* class_name = ik->name();
1155
1156 if (!is_shared_class_visible(class_name, ik, pkg_entry, class_loader)) {
1157 ik->set_shared_loading_failed();
1158 return nullptr;
1159 }
1160
1161 bool check = check_shared_class_super_types(ik, class_loader, protection_domain, CHECK_NULL);
1162 if (!check) {
1163 ik->set_shared_loading_failed();
1164 return nullptr;
1165 }
1166
1167 InstanceKlass* new_ik = nullptr;
1168 // CFLH check is skipped for VM hidden classes (see KlassFactory::create_from_stream).
1169 // It will be skipped for shared VM hidden lambda proxy classes.
1170 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1171 new_ik = KlassFactory::check_shared_class_file_load_hook(
1172 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1173 }
1174 if (new_ik != nullptr) {
1175 // The class is changed by CFLH. Return the new class. The shared class is
1176 // not used.
1177 return new_ik;
1178 }
1179
1180 // Adjust methods to recover missing data. They need addresses for
1181 // interpreter entry points and their default native method address
1182 // must be reset.
1183
1184 // Shared classes are all currently loaded by either the bootstrap or
1185 // internal parallel class loaders, so this will never cause a deadlock
1186 // on a custom class loader lock.
1187 // Since this class is already locked with parallel capable class
1188 // loaders, including the bootstrap loader via the placeholder table,
1189 // this lock is currently a nop.
1190
1191 ClassLoaderData* loader_data = class_loader_data(class_loader);
1192 {
1193 HandleMark hm(THREAD);
1194 Handle lockObject = get_loader_lock_or_null(class_loader);
1195 ObjectLocker ol(lockObject, THREAD);
1196 // prohibited package check assumes all classes loaded from archive call
1197 // restore_unshareable_info which calls ik->set_package()
1198 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1199 }
1200
1201 load_shared_class_misc(ik, loader_data);
1202 return ik;
1203 }
1204
1205 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data) {
1206 ik->print_class_load_logging(loader_data, nullptr, nullptr);
1207
1208 // For boot loader, ensure that GetSystemPackage knows that a class in this
1209 // package was loaded.
1210 if (loader_data->is_the_null_class_loader_data()) {
1211 s2 path_index = ik->shared_classpath_index();
1212 ik->set_classpath_index(path_index);
1213 }
1214
1215 // notify a class loaded from shared object
1216 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1217 }
1218
1219 #endif // INCLUDE_CDS
1220
1221 InstanceKlass* SystemDictionary::load_instance_class_impl(Symbol* class_name, Handle class_loader, TRAPS) {
1222
1223 if (class_loader.is_null()) {
1224 ResourceMark rm(THREAD);
1225 PackageEntry* pkg_entry = nullptr;
1226 bool search_only_bootloader_append = false;
1227
1228 // Find the package in the boot loader's package entry table.
1229 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1230 if (pkg_name != nullptr) {
1231 pkg_entry = class_loader_data(class_loader)->packages()->lookup_only(pkg_name);
1232 }
1233
1234 // Prior to attempting to load the class, enforce the boot loader's
1235 // visibility boundaries.
1236 if (!Universe::is_module_initialized()) {
1237 // During bootstrapping, prior to module initialization, any
1238 // class attempting to be loaded must be checked against the
1239 // java.base packages in the boot loader's PackageEntryTable.
1240 // No class outside of java.base is allowed to be loaded during
1241 // this bootstrapping window.
1242 if (pkg_entry == nullptr || pkg_entry->in_unnamed_module()) {
1243 // Class is either in the unnamed package or in
1244 // a named package within the unnamed module. Either
1245 // case is outside of java.base, do not attempt to
1246 // load the class post java.base definition. If
1247 // java.base has not been defined, let the class load
1248 // and its package will be checked later by
1249 // ModuleEntryTable::verify_javabase_packages.
1250 if (ModuleEntryTable::javabase_defined()) {
1251 return nullptr;
1252 }
1253 } else {
1254 // Check that the class' package is defined within java.base.
1255 ModuleEntry* mod_entry = pkg_entry->module();
1256 Symbol* mod_entry_name = mod_entry->name();
1257 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1258 return nullptr;
1259 }
1260 }
1261 } else {
1262 // After the module system has been initialized, check if the class'
1263 // package is in a module defined to the boot loader.
1264 if (pkg_name == nullptr || pkg_entry == nullptr || pkg_entry->in_unnamed_module()) {
1265 // Class is either in the unnamed package, in a named package
1266 // within a module not defined to the boot loader or in a
1267 // a named package within the unnamed module. In all cases,
1268 // limit visibility to search for the class only in the boot
1269 // loader's append path.
1270 if (!ClassLoader::has_bootclasspath_append()) {
1271 // If there is no bootclasspath append entry, no need to continue
1272 // searching.
1273 return nullptr;
1274 }
1275 search_only_bootloader_append = true;
1276 }
1277 }
1278
1279 // Prior to bootstrapping's module initialization, never load a class outside
1280 // of the boot loader's module path
1281 assert(Universe::is_module_initialized() ||
1282 !search_only_bootloader_append,
1283 "Attempt to load a class outside of boot loader's module path");
1284
1285 // Search for classes in the CDS archive.
1286 InstanceKlass* k = nullptr;
1287
1288 #if INCLUDE_CDS
1289 if (CDSConfig::is_using_archive())
1290 {
1291 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1292 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1293 if (ik != nullptr && ik->is_shared_boot_class() && !ik->shared_loading_failed()) {
1294 SharedClassLoadingMark slm(THREAD, ik);
1295 k = load_shared_class(ik, class_loader, Handle(), nullptr, pkg_entry, CHECK_NULL);
1296 }
1297 }
1298 #endif
1299
1300 if (k == nullptr) {
1301 // Use VM class loader
1302 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1303 k = ClassLoader::load_class(class_name, pkg_entry, search_only_bootloader_append, CHECK_NULL);
1304 }
1305
1306 // find_or_define_instance_class may return a different InstanceKlass
1307 if (k != nullptr) {
1308 CDS_ONLY(SharedClassLoadingMark slm(THREAD, k);)
1309 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_NULL);
1310 }
1311 return k;
1312 } else {
1313 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1314 ResourceMark rm(THREAD);
1315
1316 JavaThread* jt = THREAD;
1317
1318 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1319 ClassLoader::perf_app_classload_selftime(),
1320 ClassLoader::perf_app_classload_count(),
1321 jt->get_thread_stat()->perf_recursion_counts_addr(),
1322 jt->get_thread_stat()->perf_timers_addr(),
1323 PerfClassTraceTime::CLASS_LOAD);
1324
1325 // Translate to external class name format, i.e., convert '/' chars to '.'
1326 Handle string = java_lang_String::externalize_classname(class_name, CHECK_NULL);
1327
1328 JavaValue result(T_OBJECT);
1329
1330 InstanceKlass* spec_klass = vmClasses::ClassLoader_klass();
1331
1332 // Call public unsynchronized loadClass(String) directly for all class loaders.
1333 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1334 // acquire a class-name based lock rather than the class loader object lock.
1335 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1336 JavaCalls::call_virtual(&result,
1337 class_loader,
1338 spec_klass,
1339 vmSymbols::loadClass_name(),
1340 vmSymbols::string_class_signature(),
1341 string,
1342 CHECK_NULL);
1343
1344 assert(result.get_type() == T_OBJECT, "just checking");
1345 oop obj = result.get_oop();
1346
1347 // Primitive classes return null since forName() can not be
1348 // used to obtain any of the Class objects representing primitives or void
1349 if ((obj != nullptr) && !(java_lang_Class::is_primitive(obj))) {
1350 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1351 // For user defined Java class loaders, check that the name returned is
1352 // the same as that requested. This check is done for the bootstrap
1353 // loader when parsing the class file.
1354 if (class_name == k->name()) {
1355 return k;
1356 }
1357 }
1358 // Class is not found or has the wrong name, return null
1359 return nullptr;
1360 }
1361 }
1362
1363 InstanceKlass* SystemDictionary::load_instance_class(Symbol* name,
1364 Handle class_loader,
1365 TRAPS) {
1366
1367 InstanceKlass* loaded_class = load_instance_class_impl(name, class_loader, CHECK_NULL);
1368
1369 // If everything was OK (no exceptions, no null return value), and
1370 // class_loader is NOT the defining loader, do a little more bookkeeping.
1371 if (loaded_class != nullptr &&
1372 loaded_class->class_loader() != class_loader()) {
1373
1374 ClassLoaderData* loader_data = class_loader_data(class_loader);
1375 check_constraints(loaded_class, loader_data, false, CHECK_NULL);
1376
1377 // Record dependency for non-parent delegation.
1378 // This recording keeps the defining class loader of the klass (loaded_class) found
1379 // from being unloaded while the initiating class loader is loaded
1380 // even if the reference to the defining class loader is dropped
1381 // before references to the initiating class loader.
1382 loader_data->record_dependency(loaded_class);
1383
1384 update_dictionary(THREAD, loaded_class, loader_data);
1385
1386 if (JvmtiExport::should_post_class_load()) {
1387 JvmtiExport::post_class_load(THREAD, loaded_class);
1388 }
1389 }
1390 return loaded_class;
1391 }
1392
1393 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1394 EventClassDefine event;
1395 if (event.should_commit()) {
1396 event.set_definedClass(k);
1397 event.set_definingClassLoader(def_cld);
1398 event.commit();
1399 }
1400 }
1401
1402 void SystemDictionary::define_instance_class(InstanceKlass* k, Handle class_loader, TRAPS) {
1403
1404 ClassLoaderData* loader_data = k->class_loader_data();
1405 assert(loader_data->class_loader() == class_loader(), "they must be the same");
1406
1407 // Bootstrap and other parallel classloaders don't acquire a lock,
1408 // they use placeholder token.
1409 // If a parallelCapable class loader calls define_instance_class instead of
1410 // find_or_define_instance_class to get here, we have a timing
1411 // hole with systemDictionary updates and check_constraints
1412 if (!is_parallelCapable(class_loader)) {
1413 assert(ObjectSynchronizer::current_thread_holds_lock(THREAD,
1414 get_loader_lock_or_null(class_loader)),
1415 "define called without lock");
1416 }
1417
1418 // Check class-loading constraints. Throw exception if violation is detected.
1419 // Grabs and releases SystemDictionary_lock
1420 // The check_constraints/find_class call and update_dictionary sequence
1421 // must be "atomic" for a specific class/classloader pair so we never
1422 // define two different instanceKlasses for that class/classloader pair.
1423 // Existing classloaders will call define_instance_class with the
1424 // classloader lock held
1425 // Parallel classloaders will call find_or_define_instance_class
1426 // which will require a token to perform the define class
1427 check_constraints(k, loader_data, true, CHECK);
1428
1429 // Register class just loaded with class loader (placed in ArrayList)
1430 // Note we do this before updating the dictionary, as this can
1431 // fail with an OutOfMemoryError (if it does, we will *not* put this
1432 // class in the dictionary and will not update the class hierarchy).
1433 // JVMTI FollowReferences needs to find the classes this way.
1434 if (k->class_loader() != nullptr) {
1435 methodHandle m(THREAD, Universe::loader_addClass_method());
1436 JavaValue result(T_VOID);
1437 JavaCallArguments args(class_loader);
1438 args.push_oop(Handle(THREAD, k->java_mirror()));
1439 JavaCalls::call(&result, m, &args, CHECK);
1440 }
1441
1442 // Add to class hierarchy, and do possible deoptimizations.
1443 k->add_to_hierarchy(THREAD);
1444
1445 // Add to systemDictionary - so other classes can see it.
1446 // Grabs and releases SystemDictionary_lock
1447 update_dictionary(THREAD, k, loader_data);
1448
1449 // notify jvmti
1450 if (JvmtiExport::should_post_class_load()) {
1451 JvmtiExport::post_class_load(THREAD, k);
1452 }
1453 post_class_define_event(k, loader_data);
1454 }
1455
1456 // Support parallel classloading
1457 // All parallel class loaders, including bootstrap classloader
1458 // lock a placeholder entry for this class/class_loader pair
1459 // to allow parallel defines of different classes for this class loader
1460 // With AllowParallelDefine flag==true, in case they do not synchronize around
1461 // FindLoadedClass/DefineClass, calls, we check for parallel
1462 // loading for them, wait if a defineClass is in progress
1463 // and return the initial requestor's results
1464 // This flag does not apply to the bootstrap classloader.
1465 // With AllowParallelDefine flag==false, call through to define_instance_class
1466 // which will throw LinkageError: duplicate class definition.
1467 // False is the requested default.
1468 // For better performance, the class loaders should synchronize
1469 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1470 // potentially waste time reading and parsing the bytestream.
1471 // Note: VM callers should ensure consistency of k/class_name,class_loader
1472 // Be careful when modifying this code: once you have run
1473 // PlaceholderTable::find_and_add(PlaceholderTable::DEFINE_CLASS),
1474 // you need to find_and_remove it before returning.
1475 // So be careful to not exit with a CHECK_ macro between these calls.
1476 InstanceKlass* SystemDictionary::find_or_define_helper(Symbol* class_name, Handle class_loader,
1477 InstanceKlass* k, TRAPS) {
1478
1479 Symbol* name_h = k->name();
1480 ClassLoaderData* loader_data = class_loader_data(class_loader);
1481 Dictionary* dictionary = loader_data->dictionary();
1482
1483 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1484 {
1485 MutexLocker mu(THREAD, SystemDictionary_lock);
1486 // First check if class already defined
1487 if (is_parallelDefine(class_loader)) {
1488 InstanceKlass* check = dictionary->find_class(THREAD, name_h);
1489 if (check != nullptr) {
1490 return check;
1491 }
1492 }
1493
1494 // Acquire define token for this class/classloader
1495 PlaceholderEntry* probe = PlaceholderTable::find_and_add(name_h, loader_data,
1496 PlaceholderTable::DEFINE_CLASS, nullptr, THREAD);
1497 // Wait if another thread defining in parallel
1498 // All threads wait - even those that will throw duplicate class: otherwise
1499 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1500 // if other thread has not finished updating dictionary
1501 while (probe->definer() != nullptr) {
1502 SystemDictionary_lock->wait();
1503 }
1504 // Only special cases allow parallel defines and can use other thread's results
1505 // Other cases fall through, and may run into duplicate defines
1506 // caught by finding an entry in the SystemDictionary
1507 if (is_parallelDefine(class_loader) && (probe->instance_klass() != nullptr)) {
1508 InstanceKlass* ik = probe->instance_klass();
1509 PlaceholderTable::find_and_remove(name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1510 SystemDictionary_lock->notify_all();
1511 #ifdef ASSERT
1512 InstanceKlass* check = dictionary->find_class(THREAD, name_h);
1513 assert(check != nullptr, "definer missed recording success");
1514 #endif
1515 return ik;
1516 } else {
1517 // This thread will define the class (even if earlier thread tried and had an error)
1518 probe->set_definer(THREAD);
1519 }
1520 }
1521
1522 define_instance_class(k, class_loader, THREAD);
1523
1524 // definer must notify any waiting threads
1525 {
1526 MutexLocker mu(THREAD, SystemDictionary_lock);
1527 PlaceholderEntry* probe = PlaceholderTable::get_entry(name_h, loader_data);
1528 assert(probe != nullptr, "DEFINE_CLASS placeholder lost?");
1529 if (!HAS_PENDING_EXCEPTION) {
1530 probe->set_instance_klass(k);
1531 }
1532 probe->set_definer(nullptr);
1533 PlaceholderTable::find_and_remove(name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1534 SystemDictionary_lock->notify_all();
1535 }
1536
1537 return HAS_PENDING_EXCEPTION ? nullptr : k;
1538 }
1539
1540 // If a class loader supports parallel classloading handle parallel define requests.
1541 // find_or_define_instance_class may return a different InstanceKlass
1542 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1543 InstanceKlass* k, TRAPS) {
1544 InstanceKlass* defined_k = find_or_define_helper(class_name, class_loader, k, THREAD);
1545 // Clean up original InstanceKlass if duplicate or error
1546 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1547 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1548 assert(defined_k != nullptr, "Should have a klass if there's no exception");
1549 k->class_loader_data()->add_to_deallocate_list(k);
1550 } else if (HAS_PENDING_EXCEPTION) {
1551 // Remove this InstanceKlass from the LoaderConstraintTable if added.
1552 LoaderConstraintTable::remove_failed_loaded_klass(k, class_loader_data(class_loader));
1553 assert(defined_k == nullptr, "Should not have a klass if there's an exception");
1554 k->class_loader_data()->add_to_deallocate_list(k);
1555 }
1556 return defined_k;
1557 }
1558
1559
1560 // ----------------------------------------------------------------------------
1561 // GC support
1562
1563 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1564 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1565
1566 bool unloading_occurred;
1567 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1568 {
1569 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1570 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1571 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1572 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1573 if (unloading_occurred) {
1574 ConditionalMutexLocker ml2(Module_lock, is_concurrent);
1575 JFR_ONLY(Jfr::on_unloading_classes();)
1576 MANAGEMENT_ONLY(FinalizerService::purge_unloaded();)
1577 ConditionalMutexLocker ml1(SystemDictionary_lock, is_concurrent);
1578 ClassLoaderDataGraph::clean_module_and_package_info();
1579 LoaderConstraintTable::purge_loader_constraints();
1580 ResolutionErrorTable::purge_resolution_errors();
1581 }
1582 }
1583
1584 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1585
1586 if (unloading_occurred) {
1587 SymbolTable::trigger_cleanup();
1588
1589 if (java_lang_System::allow_security_manager()) {
1590 // Oops referenced by the protection domain cache table may get unreachable independently
1591 // of the class loader (eg. cached protection domain oops). So we need to
1592 // explicitly unlink them here.
1593 // All protection domain oops are linked to the caller class, so if nothing
1594 // unloads, this is not needed.
1595 ProtectionDomainCacheTable::trigger_cleanup();
1596 } else {
1597 assert(ProtectionDomainCacheTable::number_of_entries() == 0, "should be empty");
1598 }
1599
1600 ConditionalMutexLocker ml(ClassInitError_lock, is_concurrent);
1601 InstanceKlass::clean_initialization_error_table();
1602 }
1603
1604 return unloading_occurred;
1605 }
1606
1607 void SystemDictionary::methods_do(void f(Method*)) {
1608 // Walk methods in loaded classes
1609
1610 {
1611 MutexLocker ml(ClassLoaderDataGraph_lock);
1612 ClassLoaderDataGraph::methods_do(f);
1613 }
1614
1615 auto doit = [&] (InvokeMethodKey key, Method* method) {
1616 if (method != nullptr) {
1617 f(method);
1618 }
1619 };
1620
1621 {
1622 MutexLocker ml(InvokeMethodIntrinsicTable_lock);
1623 _invoke_method_intrinsic_table->iterate_all(doit);
1624 }
1625
1626 }
1627
1628 // ----------------------------------------------------------------------------
1629 // Initialization
1630
1631 void SystemDictionary::initialize(TRAPS) {
1632 _invoke_method_intrinsic_table = new (mtClass) InvokeMethodIntrinsicTable();
1633 _invoke_method_type_table = new (mtClass) InvokeMethodTypeTable();
1634 ResolutionErrorTable::initialize();
1635 LoaderConstraintTable::initialize();
1636 PlaceholderTable::initialize();
1637 ProtectionDomainCacheTable::initialize();
1638 #if INCLUDE_CDS
1639 SystemDictionaryShared::initialize();
1640 #endif
1641 // Resolve basic classes
1642 vmClasses::resolve_all(CHECK);
1643 // Resolve classes used by archived heap objects
1644 if (CDSConfig::is_using_archive()) {
1645 HeapShared::resolve_classes(THREAD);
1646 }
1647 }
1648
1649 // Constraints on class loaders. The details of the algorithm can be
1650 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1651 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1652 // that the dictionary needs to maintain a set of constraints that
1653 // must be satisfied by all classes in the dictionary.
1654 // if defining is true, then LinkageError if already in dictionary
1655 // if initiating loader, then ok if InstanceKlass matches existing entry
1656
1657 void SystemDictionary::check_constraints(InstanceKlass* k,
1658 ClassLoaderData* loader_data,
1659 bool defining,
1660 TRAPS) {
1661 ResourceMark rm(THREAD);
1662 stringStream ss;
1663 bool throwException = false;
1664
1665 {
1666 Symbol* name = k->name();
1667
1668 MutexLocker mu(THREAD, SystemDictionary_lock);
1669
1670 InstanceKlass* check = loader_data->dictionary()->find_class(THREAD, name);
1671 if (check != nullptr) {
1672 // If different InstanceKlass - duplicate class definition,
1673 // else - ok, class loaded by a different thread in parallel.
1674 // We should only have found it if it was done loading and ok to use.
1675
1676 if ((defining == true) || (k != check)) {
1677 throwException = true;
1678 ss.print("loader %s", loader_data->loader_name_and_id());
1679 ss.print(" attempted duplicate %s definition for %s. (%s)",
1680 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
1681 } else {
1682 return;
1683 }
1684 }
1685
1686 if (throwException == false) {
1687 if (LoaderConstraintTable::check_or_update(k, loader_data, name) == false) {
1688 throwException = true;
1689 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
1690 ss.print(" wants to load %s %s.",
1691 k->external_kind(), k->external_name());
1692 Klass *existing_klass = LoaderConstraintTable::find_constrained_klass(name, loader_data);
1693 if (existing_klass != nullptr && existing_klass->class_loader_data() != loader_data) {
1694 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
1695 existing_klass->external_kind(),
1696 existing_klass->class_loader_data()->loader_name_and_id(),
1697 existing_klass->class_in_module_of_loader(false, true));
1698 } else {
1699 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
1700 }
1701 }
1702 }
1703 }
1704
1705 // Throw error now if needed (cannot throw while holding
1706 // SystemDictionary_lock because of rank ordering)
1707 if (throwException == true) {
1708 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
1709 }
1710 }
1711
1712 // Update class loader data dictionary - done after check_constraint and add_to_hierarchy
1713 // have been called.
1714 void SystemDictionary::update_dictionary(JavaThread* current,
1715 InstanceKlass* k,
1716 ClassLoaderData* loader_data) {
1717 MonitorLocker mu1(SystemDictionary_lock);
1718
1719 // Make a new dictionary entry.
1720 Symbol* name = k->name();
1721 Dictionary* dictionary = loader_data->dictionary();
1722 InstanceKlass* sd_check = dictionary->find_class(current, name);
1723 if (sd_check == nullptr) {
1724 dictionary->add_klass(current, name, k);
1725 }
1726 mu1.notify_all();
1727 }
1728
1729
1730 // Try to find a class name using the loader constraints. The
1731 // loader constraints might know about a class that isn't fully loaded
1732 // yet and these will be ignored.
1733 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
1734 Thread* current, Symbol* class_name, Handle class_loader) {
1735
1736 // First see if it has been loaded directly.
1737 // Force the protection domain to be null. (This removes protection checks.)
1738 Handle no_protection_domain;
1739 Klass* klass = find_instance_or_array_klass(current, class_name, class_loader,
1740 no_protection_domain);
1741 if (klass != nullptr)
1742 return klass;
1743
1744 // Now look to see if it has been loaded elsewhere, and is subject to
1745 // a loader constraint that would require this loader to return the
1746 // klass that is already loaded.
1747 if (Signature::is_array(class_name)) {
1748 // For array classes, their Klass*s are not kept in the
1749 // constraint table. The element Klass*s are.
1750 SignatureStream ss(class_name, false);
1751 int ndims = ss.skip_array_prefix(); // skip all '['s
1752 BasicType t = ss.type();
1753 if (t != T_OBJECT) {
1754 klass = Universe::typeArrayKlass(t);
1755 } else {
1756 MutexLocker mu(current, SystemDictionary_lock);
1757 klass = LoaderConstraintTable::find_constrained_klass(ss.as_symbol(), class_loader_data(class_loader));
1758 }
1759 // If element class already loaded, allocate array klass
1760 if (klass != nullptr) {
1761 klass = klass->array_klass_or_null(ndims);
1762 }
1763 } else {
1764 MutexLocker mu(current, SystemDictionary_lock);
1765 // Non-array classes are easy: simply check the constraint table.
1766 klass = LoaderConstraintTable::find_constrained_klass(class_name, class_loader_data(class_loader));
1767 }
1768
1769 return klass;
1770 }
1771
1772 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
1773 Klass* klass_being_linked,
1774 Handle class_loader1,
1775 Handle class_loader2) {
1776 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
1777 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
1778
1779 Symbol* constraint_name = nullptr;
1780
1781 if (!Signature::is_array(class_name)) {
1782 constraint_name = class_name;
1783 } else {
1784 // For array classes, their Klass*s are not kept in the
1785 // constraint table. The element classes are.
1786 SignatureStream ss(class_name, false);
1787 ss.skip_array_prefix(); // skip all '['s
1788 if (!ss.has_envelope()) {
1789 return true; // primitive types always pass
1790 }
1791 constraint_name = ss.as_symbol();
1792 // Increment refcount to keep constraint_name alive after
1793 // SignatureStream is destructed. It will be decremented below
1794 // before returning.
1795 constraint_name->increment_refcount();
1796 }
1797
1798 Dictionary* dictionary1 = loader_data1->dictionary();
1799 Dictionary* dictionary2 = loader_data2->dictionary();
1800
1801 JavaThread* current = JavaThread::current();
1802 {
1803 MutexLocker mu_s(SystemDictionary_lock);
1804 InstanceKlass* klass1 = dictionary1->find_class(current, constraint_name);
1805 InstanceKlass* klass2 = dictionary2->find_class(current, constraint_name);
1806 bool result = LoaderConstraintTable::add_entry(constraint_name, klass1, loader_data1,
1807 klass2, loader_data2);
1808 #if INCLUDE_CDS
1809 if (CDSConfig::is_dumping_archive() && klass_being_linked != nullptr &&
1810 !klass_being_linked->is_shared()) {
1811 SystemDictionaryShared::record_linking_constraint(constraint_name,
1812 InstanceKlass::cast(klass_being_linked),
1813 class_loader1, class_loader2);
1814 }
1815 #endif // INCLUDE_CDS
1816 if (Signature::is_array(class_name)) {
1817 constraint_name->decrement_refcount();
1818 }
1819 return result;
1820 }
1821 }
1822
1823 // Add entry to resolution error table to record the error when the first
1824 // attempt to resolve a reference to a class has failed.
1825 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
1826 Symbol* error, const char* message,
1827 Symbol* cause, const char* cause_msg) {
1828 {
1829 MutexLocker ml(Thread::current(), SystemDictionary_lock);
1830 ResolutionErrorEntry* entry = ResolutionErrorTable::find_entry(pool, which);
1831 if (entry == nullptr) {
1832 ResolutionErrorTable::add_entry(pool, which, error, message, cause, cause_msg);
1833 }
1834 }
1835 }
1836
1837 // Delete a resolution error for RedefineClasses for a constant pool is going away
1838 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
1839 ResolutionErrorTable::delete_entry(pool);
1840 }
1841
1842 // Lookup resolution error table. Returns error if found, otherwise null.
1843 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
1844 const char** message,
1845 Symbol** cause, const char** cause_msg) {
1846
1847 {
1848 MutexLocker ml(Thread::current(), SystemDictionary_lock);
1849 ResolutionErrorEntry* entry = ResolutionErrorTable::find_entry(pool, which);
1850 if (entry != nullptr) {
1851 *message = entry->message();
1852 *cause = entry->cause();
1853 *cause_msg = entry->cause_msg();
1854 return entry->error();
1855 } else {
1856 return nullptr;
1857 }
1858 }
1859 }
1860
1861 // Add an entry to resolution error table to record an error in resolving or
1862 // validating a nest host. This is used to construct informative error
1863 // messages when IllegalAccessError's occur. If an entry already exists it will
1864 // be updated with the nest host error message.
1865
1866 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
1867 int which,
1868 const char* message) {
1869 {
1870 MutexLocker ml(Thread::current(), SystemDictionary_lock);
1871 ResolutionErrorEntry* entry = ResolutionErrorTable::find_entry(pool, which);
1872 if (entry != nullptr && entry->nest_host_error() == nullptr) {
1873 // An existing entry means we had a true resolution failure (LinkageError) with our nest host, but we
1874 // still want to add the error message for the higher-level access checks to report. We should
1875 // only reach here under the same error condition, so we can ignore the potential race with setting
1876 // the message. If we see it is already set then we can ignore it.
1877 entry->set_nest_host_error(message);
1878 } else {
1879 ResolutionErrorTable::add_entry(pool, which, message);
1880 }
1881 }
1882 }
1883
1884 // Lookup any nest host error
1885 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
1886 {
1887 MutexLocker ml(Thread::current(), SystemDictionary_lock);
1888 ResolutionErrorEntry* entry = ResolutionErrorTable::find_entry(pool, which);
1889 if (entry != nullptr) {
1890 return entry->nest_host_error();
1891 } else {
1892 return nullptr;
1893 }
1894 }
1895 }
1896
1897 // Signature constraints ensure that callers and callees agree about
1898 // the meaning of type names in their signatures. This routine is the
1899 // intake for constraints. It collects them from several places:
1900 //
1901 // * LinkResolver::resolve_method (if check_access is true) requires
1902 // that the resolving class (the caller) and the defining class of
1903 // the resolved method (the callee) agree on each type in the
1904 // method's signature.
1905 //
1906 // * LinkResolver::resolve_interface_method performs exactly the same
1907 // checks.
1908 //
1909 // * LinkResolver::resolve_field requires that the constant pool
1910 // attempting to link to a field agree with the field's defining
1911 // class about the type of the field signature.
1912 //
1913 // * klassVtable::initialize_vtable requires that, when a class
1914 // overrides a vtable entry allocated by a superclass, that the
1915 // overriding method (i.e., the callee) agree with the superclass
1916 // on each type in the method's signature.
1917 //
1918 // * klassItable::initialize_itable requires that, when a class fills
1919 // in its itables, for each non-abstract method installed in an
1920 // itable, the method (i.e., the callee) agree with the interface
1921 // on each type in the method's signature.
1922 //
1923 // All those methods have a boolean (check_access, checkconstraints)
1924 // which turns off the checks. This is used from specialized contexts
1925 // such as bootstrapping, dumping, and debugging.
1926 //
1927 // No direct constraint is placed between the class and its
1928 // supertypes. Constraints are only placed along linked relations
1929 // between callers and callees. When a method overrides or implements
1930 // an abstract method in a supertype (superclass or interface), the
1931 // constraints are placed as if the supertype were the caller to the
1932 // overriding method. (This works well, since callers to the
1933 // supertype have already established agreement between themselves and
1934 // the supertype.) As a result of all this, a class can disagree with
1935 // its supertype about the meaning of a type name, as long as that
1936 // class neither calls a relevant method of the supertype, nor is
1937 // called (perhaps via an override) from the supertype.
1938 //
1939 //
1940 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
1941 //
1942 // Make sure all class components (including arrays) in the given
1943 // signature will be resolved to the same class in both loaders.
1944 // Returns the name of the type that failed a loader constraint check, or
1945 // null if no constraint failed. No exception except OOME is thrown.
1946 // Arrays are not added to the loader constraint table, their elements are.
1947 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
1948 Klass* klass_being_linked,
1949 Handle loader1, Handle loader2,
1950 bool is_method) {
1951 // Nothing to do if loaders are the same.
1952 if (loader1() == loader2()) {
1953 return nullptr;
1954 }
1955
1956 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
1957 if (ss.is_reference()) {
1958 Symbol* sig = ss.as_symbol();
1959 // Note: In the future, if template-like types can take
1960 // arguments, we will want to recognize them and dig out class
1961 // names hiding inside the argument lists.
1962 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2)) {
1963 return sig;
1964 }
1965 }
1966 }
1967 return nullptr;
1968 }
1969
1970 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsicID iid,
1971 Symbol* signature,
1972 TRAPS) {
1973
1974 const int iid_as_int = vmIntrinsics::as_int(iid);
1975 assert(MethodHandles::is_signature_polymorphic(iid) &&
1976 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
1977 iid != vmIntrinsics::_invokeGeneric,
1978 "must be a known MH intrinsic iid=%d: %s", iid_as_int, vmIntrinsics::name_at(iid));
1979
1980 InvokeMethodKey key(signature, iid_as_int);
1981 Method** met = nullptr;
1982
1983 // We only want one entry in the table for this (signature/id, method) pair but the code
1984 // to create the intrinsic method needs to be outside the lock.
1985 // The first thread claims the entry by adding the key and the other threads wait, until the
1986 // Method has been added as the value.
1987 {
1988 MonitorLocker ml(THREAD, InvokeMethodIntrinsicTable_lock);
1989 while (true) {
1990 bool created;
1991 met = _invoke_method_intrinsic_table->put_if_absent(key, &created);
1992 assert(met != nullptr, "either created or found");
1993 if (*met != nullptr) {
1994 return *met;
1995 } else if (created) {
1996 // The current thread won the race and will try to create the full entry.
1997 break;
1998 } else {
1999 // Another thread beat us to it, so wait for them to complete
2000 // and return *met; or if they hit an error we get another try.
2001 ml.wait();
2002 // Note it is not safe to read *met here as that entry could have
2003 // been deleted, so we must loop and try put_if_absent again.
2004 }
2005 }
2006 }
2007
2008 methodHandle m = Method::make_method_handle_intrinsic(iid, signature, THREAD);
2009 bool throw_error = HAS_PENDING_EXCEPTION;
2010 if (!throw_error && (!Arguments::is_interpreter_only() || iid == vmIntrinsics::_linkToNative)) {
2011 // Generate a compiled form of the MH intrinsic
2012 // linkToNative doesn't have interpreter-specific implementation, so always has to go through compiled version.
2013 AdapterHandlerLibrary::create_native_wrapper(m);
2014 // Check if have the compiled code.
2015 throw_error = (!m->has_compiled_code());
2016 }
2017
2018 {
2019 MonitorLocker ml(THREAD, InvokeMethodIntrinsicTable_lock);
2020 if (throw_error) {
2021 // Remove the entry and let another thread try, or get the same exception.
2022 bool removed = _invoke_method_intrinsic_table->remove(key);
2023 assert(removed, "must be the owner");
2024 ml.notify_all();
2025 } else {
2026 signature->make_permanent(); // The signature is never unloaded.
2027 assert(Arguments::is_interpreter_only() || (m->has_compiled_code() &&
2028 m->code()->entry_point() == m->from_compiled_entry()),
2029 "MH intrinsic invariant");
2030 *met = m(); // insert the element
2031 ml.notify_all();
2032 return m();
2033 }
2034 }
2035
2036 // Throw OOM or the pending exception in the JavaThread
2037 if (throw_error && !HAS_PENDING_EXCEPTION) {
2038 THROW_MSG_NULL(vmSymbols::java_lang_OutOfMemoryError(),
2039 "Out of space in CodeCache for method handle intrinsic");
2040 }
2041 return nullptr;
2042 }
2043
2044 // Helper for unpacking the return value from linkMethod and linkCallSite.
2045 static Method* unpack_method_and_appendix(Handle mname,
2046 Klass* accessing_klass,
2047 objArrayHandle appendix_box,
2048 Handle* appendix_result,
2049 TRAPS) {
2050 if (mname.not_null()) {
2051 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2052 if (m != nullptr) {
2053 oop appendix = appendix_box->obj_at(0);
2054 LogTarget(Info, methodhandles) lt;
2055 if (lt.develop_is_enabled()) {
2056 ResourceMark rm(THREAD);
2057 LogStream ls(lt);
2058 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2059 m->print_on(&ls);
2060 if (appendix != nullptr) { ls.print("appendix = "); appendix->print_on(&ls); }
2061 ls.cr();
2062 }
2063
2064 (*appendix_result) = Handle(THREAD, appendix);
2065 // the target is stored in the cpCache and if a reference to this
2066 // MemberName is dropped we need a way to make sure the
2067 // class_loader containing this method is kept alive.
2068 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2069 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2070 this_key->record_dependency(m->method_holder());
2071 return mh();
2072 }
2073 }
2074 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2075 }
2076
2077 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2078 Symbol* name,
2079 Symbol* signature,
2080 Klass* accessing_klass,
2081 Handle* appendix_result,
2082 TRAPS) {
2083 guarantee(THREAD->can_call_java(), "");
2084 Handle method_type =
2085 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2086
2087 int ref_kind = JVM_REF_invokeVirtual;
2088 oop name_oop = StringTable::intern(name, CHECK_NULL);
2089 Handle name_str (THREAD, name_oop);
2090 objArrayHandle appendix_box = oopFactory::new_objArray_handle(vmClasses::Object_klass(), 1, CHECK_NULL);
2091 assert(appendix_box->obj_at(0) == nullptr, "");
2092
2093 // This should not happen. JDK code should take care of that.
2094 if (accessing_klass == nullptr || method_type.is_null()) {
2095 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2096 }
2097
2098 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2099 JavaCallArguments args;
2100 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2101 args.push_int(ref_kind);
2102 args.push_oop(Handle(THREAD, klass->java_mirror()));
2103 args.push_oop(name_str);
2104 args.push_oop(method_type);
2105 args.push_oop(appendix_box);
2106 JavaValue result(T_OBJECT);
2107 JavaCalls::call_static(&result,
2108 vmClasses::MethodHandleNatives_klass(),
2109 vmSymbols::linkMethod_name(),
2110 vmSymbols::linkMethod_signature(),
2111 &args, CHECK_NULL);
2112 Handle mname(THREAD, result.get_oop());
2113 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2114 }
2115
2116 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2117 // We must ensure that all class loaders everywhere will reach this class, for any client.
2118 // This is a safe bet for public classes in java.lang, such as Object and String.
2119 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2120 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2121 static bool is_always_visible_class(oop mirror) {
2122 Klass* klass = java_lang_Class::as_Klass(mirror);
2123 if (klass->is_objArray_klass()) {
2124 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2125 }
2126 if (klass->is_typeArray_klass()) {
2127 return true; // primitive array
2128 }
2129 assert(klass->is_instance_klass(), "%s", klass->external_name());
2130 return klass->is_public() &&
2131 (InstanceKlass::cast(klass)->is_same_class_package(vmClasses::Object_klass()) || // java.lang
2132 InstanceKlass::cast(klass)->is_same_class_package(vmClasses::MethodHandle_klass())); // java.lang.invoke
2133 }
2134
2135 // Find or construct the Java mirror (java.lang.Class instance) for
2136 // the given field type signature, as interpreted relative to the
2137 // given class loader. Handles primitives, void, references, arrays,
2138 // and all other reflectable types, except method types.
2139 // N.B. Code in reflection should use this entry point.
2140 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2141 Klass* accessing_klass,
2142 Handle class_loader,
2143 Handle protection_domain,
2144 SignatureStream::FailureMode failure_mode,
2145 TRAPS) {
2146 assert(accessing_klass == nullptr || (class_loader.is_null() && protection_domain.is_null()),
2147 "one or the other, or perhaps neither");
2148
2149 // What we have here must be a valid field descriptor,
2150 // and all valid field descriptors are supported.
2151 // Produce the same java.lang.Class that reflection reports.
2152 if (accessing_klass != nullptr) {
2153 class_loader = Handle(THREAD, accessing_klass->class_loader());
2154 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2155 }
2156 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2157 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2158 if (mirror_oop == nullptr) {
2159 return Handle(); // report failure this way
2160 }
2161 Handle mirror(THREAD, mirror_oop);
2162
2163 if (accessing_klass != nullptr) {
2164 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2165 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2166 if (sel_klass != nullptr) {
2167 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2168 }
2169 }
2170 return mirror;
2171 }
2172
2173
2174 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2175 // signature, as interpreted relative to the given class loader.
2176 // Because of class loader constraints, all method handle usage must be
2177 // consistent with this loader.
2178 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2179 Klass* accessing_klass,
2180 TRAPS) {
2181 Handle empty;
2182 OopHandle* o;
2183 {
2184 MutexLocker ml(THREAD, InvokeMethodTypeTable_lock);
2185 o = _invoke_method_type_table->get(signature);
2186 }
2187
2188 if (o != nullptr) {
2189 oop mt = o->resolve();
2190 assert(java_lang_invoke_MethodType::is_instance(mt), "");
2191 return Handle(THREAD, mt);
2192 } else if (!THREAD->can_call_java()) {
2193 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2194 return Handle(); // do not attempt from within compiler, unless it was cached
2195 }
2196
2197 Handle class_loader, protection_domain;
2198 if (accessing_klass != nullptr) {
2199 class_loader = Handle(THREAD, accessing_klass->class_loader());
2200 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2201 }
2202 bool can_be_cached = true;
2203 int npts = ArgumentCount(signature).size();
2204 objArrayHandle pts = oopFactory::new_objArray_handle(vmClasses::Class_klass(), npts, CHECK_(empty));
2205 int arg = 0;
2206 Handle rt; // the return type from the signature
2207 ResourceMark rm(THREAD);
2208 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2209 oop mirror = nullptr;
2210 if (can_be_cached) {
2211 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2212 mirror = ss.as_java_mirror(Handle(), Handle(),
2213 SignatureStream::ReturnNull, CHECK_(empty));
2214 if (mirror == nullptr || (ss.is_reference() && !is_always_visible_class(mirror))) {
2215 // Fall back to accessing_klass context.
2216 can_be_cached = false;
2217 }
2218 }
2219 if (!can_be_cached) {
2220 // Resolve, throwing a real error if it doesn't work.
2221 mirror = ss.as_java_mirror(class_loader, protection_domain,
2222 SignatureStream::NCDFError, CHECK_(empty));
2223 }
2224 assert(mirror != nullptr, "%s", ss.as_symbol()->as_C_string());
2225 if (ss.at_return_type())
2226 rt = Handle(THREAD, mirror);
2227 else
2228 pts->obj_at_put(arg++, mirror);
2229
2230 // Check accessibility.
2231 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != nullptr) {
2232 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2233 mirror = nullptr; // safety
2234 // Emulate ConstantPool::verify_constant_pool_resolve.
2235 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2236 }
2237 }
2238 assert(arg == npts, "");
2239
2240 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2241 JavaCallArguments args(Handle(THREAD, rt()));
2242 args.push_oop(pts);
2243 JavaValue result(T_OBJECT);
2244 JavaCalls::call_static(&result,
2245 vmClasses::MethodHandleNatives_klass(),
2246 vmSymbols::findMethodHandleType_name(),
2247 vmSymbols::findMethodHandleType_signature(),
2248 &args, CHECK_(empty));
2249 Handle method_type(THREAD, result.get_oop());
2250
2251 if (can_be_cached) {
2252 // We can cache this MethodType inside the JVM.
2253 MutexLocker ml(THREAD, InvokeMethodTypeTable_lock);
2254 bool created = false;
2255 assert(method_type != nullptr, "unexpected null");
2256 OopHandle* h = _invoke_method_type_table->get(signature);
2257 if (h == nullptr) {
2258 signature->make_permanent(); // The signature is never unloaded.
2259 OopHandle elem = OopHandle(Universe::vm_global(), method_type());
2260 bool created = _invoke_method_type_table->put(signature, elem);
2261 assert(created, "better be created");
2262 }
2263 }
2264 // report back to the caller with the MethodType
2265 return method_type;
2266 }
2267
2268 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2269 Klass* accessing_klass,
2270 TRAPS) {
2271 Handle empty;
2272 ResourceMark rm(THREAD);
2273 SignatureStream ss(signature, /*is_method=*/ false);
2274 if (!ss.is_done()) {
2275 Handle class_loader, protection_domain;
2276 if (accessing_klass != nullptr) {
2277 class_loader = Handle(THREAD, accessing_klass->class_loader());
2278 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2279 }
2280 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2281 ss.next();
2282 if (ss.is_done()) {
2283 return Handle(THREAD, mirror);
2284 }
2285 }
2286 return empty;
2287 }
2288
2289 // Ask Java code to find or construct a method handle constant.
2290 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2291 int ref_kind, //e.g., JVM_REF_invokeVirtual
2292 Klass* callee,
2293 Symbol* name,
2294 Symbol* signature,
2295 TRAPS) {
2296 Handle empty;
2297 if (caller == nullptr) {
2298 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2299 }
2300 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2301 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2302
2303 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2304 Handle mname = vmClasses::MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2305 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2306 java_lang_invoke_MemberName::set_name (mname(), name_str());
2307 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2308 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2309
2310 if (ref_kind == JVM_REF_invokeVirtual &&
2311 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2312 // Skip resolution for public signature polymorphic methods such as
2313 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2314 // They require appendix argument which MemberName resolution doesn't handle.
2315 // There's special logic on JDK side to handle them
2316 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2317 } else {
2318 MethodHandles::resolve_MemberName(mname, caller, 0, false /*speculative_resolve*/, CHECK_(empty));
2319 }
2320
2321 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2322 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2323
2324 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2325 JavaCallArguments args;
2326 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2327 args.push_int(ref_kind);
2328 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2329 args.push_oop(name_str);
2330 args.push_oop(type);
2331 JavaValue result(T_OBJECT);
2332 JavaCalls::call_static(&result,
2333 vmClasses::MethodHandleNatives_klass(),
2334 vmSymbols::linkMethodHandleConstant_name(),
2335 vmSymbols::linkMethodHandleConstant_signature(),
2336 &args, CHECK_(empty));
2337 return Handle(THREAD, result.get_oop());
2338 }
2339
2340 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2341 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2342 // with linkage results being stored back into the bootstrap specifier.
2343 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2344 // Resolve the bootstrap specifier, its name, type, and static arguments
2345 bootstrap_specifier.resolve_bsm(CHECK);
2346
2347 // This should not happen. JDK code should take care of that.
2348 if (bootstrap_specifier.caller() == nullptr || bootstrap_specifier.type_arg().is_null()) {
2349 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2350 }
2351
2352 bool is_indy = bootstrap_specifier.is_method_call();
2353 objArrayHandle appendix_box;
2354 if (is_indy) {
2355 // Some method calls may require an appendix argument. Arrange to receive it.
2356 appendix_box = oopFactory::new_objArray_handle(vmClasses::Object_klass(), 1, CHECK);
2357 assert(appendix_box->obj_at(0) == nullptr, "");
2358 }
2359
2360 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, bsm, type, info)
2361 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2362 JavaCallArguments args;
2363 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2364 args.push_oop(bootstrap_specifier.bsm());
2365 args.push_oop(bootstrap_specifier.name_arg());
2366 args.push_oop(bootstrap_specifier.type_arg());
2367 args.push_oop(bootstrap_specifier.arg_values());
2368 if (is_indy) {
2369 args.push_oop(appendix_box);
2370 }
2371 JavaValue result(T_OBJECT);
2372 JavaCalls::call_static(&result,
2373 vmClasses::MethodHandleNatives_klass(),
2374 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2375 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2376 &args, CHECK);
2377
2378 Handle value(THREAD, result.get_oop());
2379 if (is_indy) {
2380 Handle appendix;
2381 Method* method = unpack_method_and_appendix(value,
2382 bootstrap_specifier.caller(),
2383 appendix_box,
2384 &appendix, CHECK);
2385 methodHandle mh(THREAD, method);
2386 bootstrap_specifier.set_resolved_method(mh, appendix);
2387 } else {
2388 bootstrap_specifier.set_resolved_value(value);
2389 }
2390
2391 // sanity check
2392 assert(bootstrap_specifier.is_resolved() ||
2393 (bootstrap_specifier.is_method_call() &&
2394 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2395 }
2396
2397
2398 bool SystemDictionary::is_nonpublic_Object_method(Method* m) {
2399 assert(m != nullptr, "Unexpected nullptr Method*");
2400 return !m->is_public() && m->method_holder() == vmClasses::Object_klass();
2401 }
2402
2403 // ----------------------------------------------------------------------------
2404
2405 void SystemDictionary::print_on(outputStream *st) {
2406 CDS_ONLY(SystemDictionaryShared::print_on(st));
2407 GCMutexLocker mu(SystemDictionary_lock);
2408
2409 ClassLoaderDataGraph::print_dictionary(st);
2410
2411 // Placeholders
2412 PlaceholderTable::print_on(st);
2413 st->cr();
2414
2415 // loader constraints - print under SD_lock
2416 LoaderConstraintTable::print_on(st);
2417 st->cr();
2418
2419 ProtectionDomainCacheTable::print_on(st);
2420 st->cr();
2421 }
2422
2423 void SystemDictionary::print() { print_on(tty); }
2424
2425 void SystemDictionary::verify() {
2426
2427 GCMutexLocker mu(SystemDictionary_lock);
2428
2429 // Verify dictionary
2430 ClassLoaderDataGraph::verify_dictionary();
2431
2432 // Verify constraint table
2433 LoaderConstraintTable::verify();
2434
2435 // Verify protection domain table
2436 ProtectionDomainCacheTable::verify();
2437 }
2438
2439 void SystemDictionary::dump(outputStream *st, bool verbose) {
2440 assert_locked_or_safepoint(SystemDictionary_lock);
2441 if (verbose) {
2442 print_on(st);
2443 } else {
2444 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2445 ClassLoaderDataGraph::print_table_statistics(st);
2446 LoaderConstraintTable::print_table_statistics(st);
2447 ProtectionDomainCacheTable::print_table_statistics(st);
2448 }
2449 }
2450
2451 // Utility for dumping dictionaries.
2452 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2453 DCmdWithParser(output, heap),
2454 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2455 "BOOLEAN", false, "false") {
2456 _dcmdparser.add_dcmd_option(&_verbose);
2457 }
2458
2459 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2460 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2461 _verbose.value());
2462 VMThread::execute(&dumper);
2463 }