1 /*
2 * Copyright (c) 1997, 2020, 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 "jvm.h"
27 #include "aot/aotLoader.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/vmSymbols.hpp"
47 #include "code/codeCache.hpp"
48 #include "compiler/compileBroker.hpp"
49 #include "gc/shared/gcTraceTime.inline.hpp"
50 #include "interpreter/bytecodeStream.hpp"
51 #include "interpreter/interpreter.hpp"
52 #include "jfr/jfrEvents.hpp"
53 #include "logging/log.hpp"
54 #include "logging/logStream.hpp"
55 #include "memory/filemap.hpp"
56 #include "memory/heapShared.hpp"
57 #include "memory/metaspaceClosure.hpp"
58 #include "memory/oopFactory.hpp"
59 #include "memory/resourceArea.hpp"
60 #include "memory/universe.hpp"
61 #include "oops/access.inline.hpp"
62 #include "oops/instanceKlass.hpp"
63 #include "oops/instanceRefKlass.hpp"
64 #include "oops/klass.inline.hpp"
65 #include "oops/method.inline.hpp"
66 #include "oops/methodData.hpp"
67 #include "oops/objArrayKlass.hpp"
68 #include "oops/objArrayOop.inline.hpp"
69 #include "oops/oop.inline.hpp"
70 #include "oops/oopHandle.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #include "utilities/utf8.hpp"
88 #if INCLUDE_CDS
89 #include "classfile/systemDictionaryShared.hpp"
90 #endif
91 #if INCLUDE_JFR
92 #include "jfr/jfr.hpp"
93 #endif
94
95 PlaceholderTable* SystemDictionary::_placeholders = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106
107 OopHandle SystemDictionary::_system_loader_lock_obj;
108 OopHandle SystemDictionary::_java_system_loader;
109 OopHandle SystemDictionary::_java_platform_loader;
110
111 // Default ProtectionDomainCacheSize value
112
113 const int defaultProtectionDomainCacheSize = 1009;
114
115 // ----------------------------------------------------------------------------
116 // Java-level SystemLoader and PlatformLoader
117
118 oop SystemDictionary::system_loader_lock() {
119 return _system_loader_lock_obj.resolve();
120 }
121
122 oop SystemDictionary::java_system_loader() {
123 return _java_system_loader.resolve();
124 }
125
126 oop SystemDictionary::java_platform_loader() {
127 return _java_platform_loader.resolve();
128 }
129
130 void SystemDictionary::compute_java_loaders(TRAPS) {
131 JavaValue result(T_OBJECT);
132 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
133 JavaCalls::call_static(&result,
134 class_loader_klass,
135 vmSymbols::getSystemClassLoader_name(),
136 vmSymbols::void_classloader_signature(),
137 CHECK);
138
139 _java_system_loader = OopHandle(Universe::vm_global(), (oop)result.get_jobject());
140
141 JavaCalls::call_static(&result,
142 class_loader_klass,
143 vmSymbols::getPlatformClassLoader_name(),
144 vmSymbols::void_classloader_signature(),
145 CHECK);
146
147 _java_platform_loader = OopHandle(Universe::vm_global(), (oop)result.get_jobject());
148 }
149
150 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
151 if (create_mirror_cld) {
152 // Add a new class loader data to the graph.
153 return ClassLoaderDataGraph::add(class_loader, true);
154 } else {
155 return (class_loader() == NULL) ? ClassLoaderData::the_null_class_loader_data() :
156 ClassLoaderDataGraph::find_or_create(class_loader);
157 }
158 }
159
160 // ----------------------------------------------------------------------------
161 // Parallel class loading check
162
163 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
164 if (class_loader.is_null()) return true;
165 if (AlwaysLockClassLoader) return false;
166 return java_lang_ClassLoader::parallelCapable(class_loader());
167 }
168 // ----------------------------------------------------------------------------
169 // ParallelDefineClass flag does not apply to bootclass loader
170 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
171 if (class_loader.is_null()) return false;
172 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
173 return true;
174 }
175 return false;
176 }
177
178 // Returns true if the passed class loader is the builtin application class loader
179 // or a custom system class loader. A customer system class loader can be
180 // specified via -Djava.system.class.loader.
181 bool SystemDictionary::is_system_class_loader(oop class_loader) {
182 if (class_loader == NULL) {
183 return false;
184 }
185 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
186 class_loader == _java_system_loader.peek());
187 }
188
189 // Returns true if the passed class loader is the platform class loader.
190 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
191 if (class_loader == NULL) {
192 return false;
193 }
194 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
195 }
196
197 // ----------------------------------------------------------------------------
198 // Resolving of classes
199
200 Symbol* SystemDictionary::class_name_symbol(const char* name, Symbol* exception, TRAPS) {
201 if (name == NULL) {
202 THROW_MSG_0(exception, "No class name given");
203 }
204 if ((int)strlen(name) > Symbol::max_length()) {
205 // It's impossible to create this class; the name cannot fit
206 // into the constant pool.
207 Exceptions::fthrow(THREAD_AND_LOCATION, exception,
208 "Class name exceeds maximum length of %d: %s",
209 Symbol::max_length(),
210 name);
211 return NULL;
212 }
213 // Callers should ensure that the name is never an illegal UTF8 string.
214 assert(UTF8::is_legal_utf8((const unsigned char*)name, (int)strlen(name), false),
215 "Class name is not a valid utf8 string.");
216
217 // Make a new symbol for the class name.
218 return SymbolTable::new_symbol(name);
219 }
220
221 // Forwards to resolve_or_null
222
223 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
224 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
225 if (HAS_PENDING_EXCEPTION || klass == NULL) {
226 // can return a null klass
227 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
228 }
229 return klass;
230 }
231
232 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
233 bool throw_error,
234 Klass* klass, TRAPS) {
235 if (HAS_PENDING_EXCEPTION) {
236 // If we have a pending exception we forward it to the caller, unless throw_error is true,
237 // in which case we have to check whether the pending exception is a ClassNotFoundException,
238 // and if so convert it to a NoClassDefFoundError
239 // And chain the original ClassNotFoundException
240 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
241 ResourceMark rm(THREAD);
242 assert(klass == NULL, "Should not have result with exception pending");
243 Handle e(THREAD, PENDING_EXCEPTION);
244 CLEAR_PENDING_EXCEPTION;
245 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
246 } else {
247 return NULL;
248 }
249 }
250 // Class not found, throw appropriate error or exception depending on value of throw_error
251 if (klass == NULL) {
252 ResourceMark rm(THREAD);
253 if (throw_error) {
254 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
255 } else {
256 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
257 }
258 }
259 return klass;
260 }
261
262
263 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
264 bool throw_error, TRAPS)
265 {
266 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
267 }
268
269
270 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
271
272 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
273 if (Signature::is_array(class_name)) {
274 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
275 } else {
276 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
277 }
278 }
279
280 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
281 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
282 Handle class_loader,
283 Handle protection_domain,
284 TRAPS) {
285 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
286 if (Signature::has_envelope(class_name)) {
287 ResourceMark rm(THREAD);
288 // Ignore wrapping L and ;.
289 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
290 class_name->utf8_length() - 2);
291 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
292 } else {
293 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
294 }
295 }
296
297 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
298 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
299 }
300
301 // Forwards to resolve_instance_class_or_null
302
303 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
304 Handle class_loader,
305 Handle protection_domain,
306 TRAPS) {
307 assert(Signature::is_array(class_name), "must be array");
308 ResourceMark rm(THREAD);
309 SignatureStream ss(class_name, false);
310 int ndims = ss.skip_array_prefix(); // skip all '['s
311 Klass* k = NULL;
312 BasicType t = ss.type();
313 if (ss.has_envelope()) {
314 Symbol* obj_class = ss.as_symbol();
315 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
316 class_loader,
317 protection_domain,
318 CHECK_NULL);
319 if (k != NULL) {
320 k = k->array_klass(ndims, CHECK_NULL);
321 }
322 } else {
323 k = Universe::typeArrayKlassObj(t);
324 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
325 }
326 return k;
327 }
328
329
330 // Must be called for any super-class or super-interface resolution
331 // during class definition to allow class circularity checking
332 // super-interface callers:
333 // parse_interfaces - for defineClass & jvmtiRedefineClasses
334 // super-class callers:
335 // ClassFileParser - for defineClass & jvmtiRedefineClasses
336 // load_shared_class - while loading a class from shared archive
337 // resolve_instance_class_or_null:
338 // via: handle_parallel_super_load
339 // when resolving a class that has an existing placeholder with
340 // a saved superclass [i.e. a defineClass is currently in progress]
341 // if another thread is trying to resolve the class, it must do
342 // super-class checks on its own thread to catch class circularity
343 // This last call is critical in class circularity checking for cases
344 // where classloading is delegated to different threads and the
345 // classloader lock is released.
346 // Take the case: Base->Super->Base
347 // 1. If thread T1 tries to do a defineClass of class Base
348 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
349 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
350 // so it tries to load Super
351 // 3. If we load the class internally, or user classloader uses same thread
352 // loadClassFromxxx or defineClass via parseClassFile Super ...
353 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
354 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
355 // 3.4 calls resolve_super_or_fail Base
356 // 3.5 finds T1,Base -> throws class circularity
357 //OR 4. If T2 tries to resolve Super via defineClass Super ...
358 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
359 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
360 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
361 // 4.4 finds T2, Super -> throws class circularity
362 // Must be called, even if superclass is null, since this is
363 // where the placeholder entry is created which claims this
364 // thread is loading this class/classloader.
365 // Be careful when modifying this code: once you have run
366 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
367 // you need to find_and_remove it before returning.
368 // So be careful to not exit with a CHECK_ macro betweeen these calls.
369 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
370 Symbol* super_name,
371 Handle class_loader,
372 Handle protection_domain,
373 bool is_superclass,
374 TRAPS) {
375 assert(!Signature::is_array(super_name), "invalid super class name");
376 #if INCLUDE_CDS
377 if (DumpSharedSpaces) {
378 // Special processing for handling UNREGISTERED shared classes.
379 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
380 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
381 if (k) {
382 return k;
383 }
384 }
385 #endif // INCLUDE_CDS
386
387 // Double-check, if child class is already loaded, just return super-class,interface
388 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
389 // dictionary.
390 // Make sure there's a placeholder for the *child* before resolving.
391 // Used as a claim that this thread is currently loading superclass/classloader
392 // Used here for ClassCircularity checks and also for heap verification
393 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
394 // Must check ClassCircularity before checking if super class is already loaded.
395 //
396 // We might not already have a placeholder if this child_name was
397 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
398 // the name of the class might not be known until the stream is actually
399 // parsed.
400 // Bugs 4643874, 4715493
401
402 ClassLoaderData* loader_data = class_loader_data(class_loader);
403 Dictionary* dictionary = loader_data->dictionary();
404 unsigned int d_hash = dictionary->compute_hash(child_name);
405 unsigned int p_hash = placeholders()->compute_hash(child_name);
406 int p_index = placeholders()->hash_to_index(p_hash);
407 // can't throw error holding a lock
408 bool child_already_loaded = false;
409 bool throw_circularity_error = false;
410 {
411 MutexLocker mu(THREAD, SystemDictionary_lock);
412 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
413 InstanceKlass* quicksuperk;
414 // to support // loading: if child done loading, just return superclass
415 // if super_name, & class_loader don't match:
416 // if initial define, SD update will give LinkageError
417 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
418 // so we don't throw an exception here.
419 // see: nsk redefclass014 & java.lang.instrument Instrument032
420 if ((childk != NULL ) && (is_superclass) &&
421 ((quicksuperk = childk->java_super()) != NULL) &&
422 ((quicksuperk->name() == super_name) &&
423 (quicksuperk->class_loader() == class_loader()))) {
424 return quicksuperk;
425 } else {
426 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
427 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
428 throw_circularity_error = true;
429 }
430 }
431 if (!throw_circularity_error) {
432 // Be careful not to exit resolve_super
433 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
434 }
435 }
436 if (throw_circularity_error) {
437 ResourceMark rm(THREAD);
438 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
439 }
440
441 // java.lang.Object should have been found above
442 assert(super_name != NULL, "null super class for resolving");
443 // Resolve the super class or interface, check results on return
444 InstanceKlass* superk =
445 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
446 class_loader,
447 protection_domain,
448 THREAD);
449
450 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
451 // It is no longer necessary to keep the placeholder table alive until update_dictionary
452 // or error. GC used to walk the placeholder table as strong roots.
453 // The instanceKlass is kept alive because the class loader is on the stack,
454 // which keeps the loader_data alive, as well as all instanceKlasses in
455 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
456 {
457 MutexLocker mu(THREAD, SystemDictionary_lock);
458 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
459 SystemDictionary_lock->notify_all();
460 }
461 if (HAS_PENDING_EXCEPTION || superk == NULL) {
462 // can null superk
463 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
464 assert(k == NULL || k == superk, "must be");
465 if (k == NULL) {
466 superk = NULL;
467 }
468 }
469
470 return superk;
471 }
472
473 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
474 Handle class_loader,
475 Handle protection_domain,
476 TRAPS) {
477 // Now we have to call back to java to check if the initating class has access
478 JavaValue result(T_VOID);
479 LogTarget(Debug, protectiondomain) lt;
480 if (lt.is_enabled()) {
481 ResourceMark rm(THREAD);
482 // Print out trace information
483 LogStream ls(lt);
484 ls.print_cr("Checking package access");
485 if (class_loader() != NULL) {
486 ls.print("class loader: ");
487 class_loader()->print_value_on(&ls);
488 } else {
489 ls.print_cr("class loader: NULL");
490 }
491 if (protection_domain() != NULL) {
492 ls.print(" protection domain: ");
493 protection_domain()->print_value_on(&ls);
494 } else {
495 ls.print_cr(" protection domain: NULL");
496 }
497 ls.print(" loading: "); klass->print_value_on(&ls);
498 ls.cr();
499 }
500
501 // This handle and the class_loader handle passed in keeps this class from
502 // being unloaded through several GC points.
503 // The class_loader handle passed in is the initiating loader.
504 Handle mirror(THREAD, klass->java_mirror());
505
506 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
507 JavaCalls::call_special(&result,
508 class_loader,
509 system_loader,
510 vmSymbols::checkPackageAccess_name(),
511 vmSymbols::class_protectiondomain_signature(),
512 mirror,
513 protection_domain,
514 THREAD);
515
516 if (HAS_PENDING_EXCEPTION) {
517 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
518 } else {
519 log_debug(protectiondomain)("granted");
520 }
521
522 if (HAS_PENDING_EXCEPTION) return;
523
524 // If no exception has been thrown, we have validated the protection domain
525 // Insert the protection domain of the initiating class into the set.
526 {
527 ClassLoaderData* loader_data = class_loader_data(class_loader);
528 Dictionary* dictionary = loader_data->dictionary();
529
530 Symbol* kn = klass->name();
531 unsigned int d_hash = dictionary->compute_hash(kn);
532
533 MutexLocker mu(THREAD, SystemDictionary_lock);
534 int d_index = dictionary->hash_to_index(d_hash);
535 dictionary->add_protection_domain(d_index, d_hash, klass,
536 protection_domain, THREAD);
537 }
538 }
539
540 // We only get here if this thread finds that another thread
541 // has already claimed the placeholder token for the current operation,
542 // but that other thread either never owned or gave up the
543 // object lock
544 // Waits on SystemDictionary_lock to indicate placeholder table updated
545 // On return, caller must recheck placeholder table state
546 //
547 // We only get here if
548 // 1) custom classLoader, i.e. not bootstrap classloader
549 // 2) custom classLoader has broken the class loader objectLock
550 // so another thread got here in parallel
551 //
552 // lockObject must be held.
553 // Complicated dance due to lock ordering:
554 // Must first release the classloader object lock to
555 // allow initial definer to complete the class definition
556 // and to avoid deadlock
557 // Reclaim classloader lock object with same original recursion count
558 // Must release SystemDictionary_lock after notify, since
559 // class loader lock must be claimed before SystemDictionary_lock
560 // to prevent deadlocks
561 //
562 // The notify allows applications that did an untimed wait() on
563 // the classloader object lock to not hang.
564 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
565 assert_lock_strong(SystemDictionary_lock);
566
567 bool calledholdinglock
568 = ObjectSynchronizer::current_thread_holds_lock(THREAD->as_Java_thread(), lockObject);
569 assert(calledholdinglock,"must hold lock for notify");
570 assert((lockObject() != _system_loader_lock_obj.resolve() &&
571 !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
572 ObjectSynchronizer::notifyall(lockObject, THREAD);
573 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
574 SystemDictionary_lock->wait();
575 SystemDictionary_lock->unlock();
576 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
577 SystemDictionary_lock->lock();
578 }
579
580 // If the class in is in the placeholder table, class loading is in progress
581 // For cases where the application changes threads to load classes, it
582 // is critical to ClassCircularity detection that we try loading
583 // the superclass on the same thread internally, so we do parallel
584 // super class loading here.
585 // This also is critical in cases where the original thread gets stalled
586 // even in non-circularity situations.
587 // Note: must call resolve_super_or_fail even if null super -
588 // to force placeholder entry creation for this class for circularity detection
589 // Caller must check for pending exception
590 // Returns non-null Klass* if other thread has completed load
591 // and we are done,
592 // If return null Klass* and no pending exception, the caller must load the class
593 InstanceKlass* SystemDictionary::handle_parallel_super_load(
594 Symbol* name, Symbol* superclassname, Handle class_loader,
595 Handle protection_domain, Handle lockObject, TRAPS) {
596
597 ClassLoaderData* loader_data = class_loader_data(class_loader);
598 Dictionary* dictionary = loader_data->dictionary();
599 unsigned int d_hash = dictionary->compute_hash(name);
600 unsigned int p_hash = placeholders()->compute_hash(name);
601 int p_index = placeholders()->hash_to_index(p_hash);
602
603 // superk is not used, resolve_super called for circularity check only
604 // This code is reached in two situations. One if this thread
605 // is loading the same class twice (e.g. ClassCircularity, or
606 // java.lang.instrument).
607 // The second is if another thread started the resolve_super first
608 // and has not yet finished.
609 // In both cases the original caller will clean up the placeholder
610 // entry on error.
611 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
612 superclassname,
613 class_loader,
614 protection_domain,
615 true,
616 CHECK_NULL);
617
618 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
619 // Serial class loaders and bootstrap classloader do wait for superclass loads
620 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
621 MutexLocker mu(THREAD, SystemDictionary_lock);
622 // Check if classloading completed while we were loading superclass or waiting
623 return find_class(d_hash, name, dictionary);
624 }
625
626 // must loop to both handle other placeholder updates
627 // and spurious notifications
628 bool super_load_in_progress = true;
629 PlaceholderEntry* placeholder;
630 while (super_load_in_progress) {
631 MutexLocker mu(THREAD, SystemDictionary_lock);
632 // Check if classloading completed while we were loading superclass or waiting
633 InstanceKlass* check = find_class(d_hash, name, dictionary);
634 if (check != NULL) {
635 // Klass is already loaded, so just return it
636 return check;
637 } else {
638 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
639 if (placeholder && placeholder->super_load_in_progress() ){
640 // We only get here if the application has released the
641 // classloader lock when another thread was in the middle of loading a
642 // superclass/superinterface for this class, and now
643 // this thread is also trying to load this class.
644 // To minimize surprises, the first thread that started to
645 // load a class should be the one to complete the loading
646 // with the classfile it initially expected.
647 // This logic has the current thread wait once it has done
648 // all the superclass/superinterface loading it can, until
649 // the original thread completes the class loading or fails
650 // If it completes we will use the resulting InstanceKlass
651 // which we will find below in the systemDictionary.
652 // We also get here for parallel bootstrap classloader
653 if (class_loader.is_null()) {
654 SystemDictionary_lock->wait();
655 } else {
656 double_lock_wait(lockObject, THREAD);
657 }
658 } else {
659 // If not in SD and not in PH, other thread's load must have failed
660 super_load_in_progress = false;
661 }
662 }
663 }
664 return NULL;
665 }
666
667 void SystemDictionary::post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
668 assert(event != NULL, "invariant");
669 assert(k != NULL, "invariant");
670 assert(event->should_commit(), "invariant");
671 event->set_loadedClass(k);
672 event->set_definingClassLoader(k->class_loader_data());
673 event->set_initiatingClassLoader(init_cld);
674 event->commit();
675 }
676
677
678 // Be careful when modifying this code: once you have run
679 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
680 // you need to find_and_remove it before returning.
681 // So be careful to not exit with a CHECK_ macro betweeen these calls.
682 //
683 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
684 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
685 Handle class_loader,
686 Handle protection_domain,
687 TRAPS) {
688 assert(name != NULL && !Signature::is_array(name) &&
689 !Signature::has_envelope(name), "invalid class name");
690
691 EventClassLoad class_load_start_event;
692
693 HandleMark hm(THREAD);
694
695 // Fix for 4474172; see evaluation for more details
696 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
697 ClassLoaderData* loader_data = register_loader(class_loader);
698 Dictionary* dictionary = loader_data->dictionary();
699 unsigned int d_hash = dictionary->compute_hash(name);
700
701 // Do lookup to see if class already exist and the protection domain
702 // has the right access
703 // This call uses find which checks protection domain already matches
704 // All subsequent calls use find_class, and set has_loaded_class so that
705 // before we return a result we call out to java to check for valid protection domain
706 // to allow returning the Klass* and add it to the pd_set if it is valid
707 {
708 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
709 if (probe != NULL) return probe;
710 }
711
712 // Non-bootstrap class loaders will call out to class loader and
713 // define via jvm/jni_DefineClass which will acquire the
714 // class loader object lock to protect against multiple threads
715 // defining the class in parallel by accident.
716 // This lock must be acquired here so the waiter will find
717 // any successful result in the SystemDictionary and not attempt
718 // the define.
719 // ParallelCapable Classloaders and the bootstrap classloader
720 // do not acquire lock here.
721 bool DoObjectLock = true;
722 if (is_parallelCapable(class_loader)) {
723 DoObjectLock = false;
724 }
725
726 unsigned int p_hash = placeholders()->compute_hash(name);
727 int p_index = placeholders()->hash_to_index(p_hash);
728
729 // Class is not in SystemDictionary so we have to do loading.
730 // Make sure we are synchronized on the class loader before we proceed
731 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
732 check_loader_lock_contention(lockObject, THREAD);
733 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
734
735 // Check again (after locking) if class already exist in SystemDictionary
736 bool class_has_been_loaded = false;
737 bool super_load_in_progress = false;
738 bool havesupername = false;
739 InstanceKlass* k = NULL;
740 PlaceholderEntry* placeholder;
741 Symbol* superclassname = NULL;
742
743 assert(THREAD->can_call_java(),
744 "can not load classes with compiler thread: class=%s, classloader=%s",
745 name->as_C_string(),
746 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
747 {
748 MutexLocker mu(THREAD, SystemDictionary_lock);
749 InstanceKlass* check = find_class(d_hash, name, dictionary);
750 if (check != NULL) {
751 // InstanceKlass is already loaded, so just return it
752 class_has_been_loaded = true;
753 k = check;
754 } else {
755 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
756 if (placeholder && placeholder->super_load_in_progress()) {
757 super_load_in_progress = true;
758 if (placeholder->havesupername() == true) {
759 superclassname = placeholder->supername();
760 havesupername = true;
761 }
762 }
763 }
764 }
765
766 // If the class is in the placeholder table, class loading is in progress
767 if (super_load_in_progress && havesupername==true) {
768 k = handle_parallel_super_load(name,
769 superclassname,
770 class_loader,
771 protection_domain,
772 lockObject, THREAD);
773 if (HAS_PENDING_EXCEPTION) {
774 return NULL;
775 }
776 if (k != NULL) {
777 class_has_been_loaded = true;
778 }
779 }
780
781 bool throw_circularity_error = false;
782 if (!class_has_been_loaded) {
783 bool load_instance_added = false;
784
785 // add placeholder entry to record loading instance class
786 // Five cases:
787 // All cases need to prevent modifying bootclasssearchpath
788 // in parallel with a classload of same classname
789 // Redefineclasses uses existence of the placeholder for the duration
790 // of the class load to prevent concurrent redefinition of not completely
791 // defined classes.
792 // case 1. traditional classloaders that rely on the classloader object lock
793 // - no other need for LOAD_INSTANCE
794 // case 2. traditional classloaders that break the classloader object lock
795 // as a deadlock workaround. Detection of this case requires that
796 // this check is done while holding the classloader object lock,
797 // and that lock is still held when calling classloader's loadClass.
798 // For these classloaders, we ensure that the first requestor
799 // completes the load and other requestors wait for completion.
800 // case 3. Bootstrap classloader - don't own objectLocker
801 // This classloader supports parallelism at the classloader level,
802 // but only allows a single load of a class/classloader pair.
803 // No performance benefit and no deadlock issues.
804 // case 4. parallelCapable user level classloaders - without objectLocker
805 // Allow parallel classloading of a class/classloader pair
806
807 {
808 MutexLocker mu(THREAD, SystemDictionary_lock);
809 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
810 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
811 if (oldprobe) {
812 // only need check_seen_thread once, not on each loop
813 // 6341374 java/lang/Instrument with -Xcomp
814 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
815 throw_circularity_error = true;
816 } else {
817 // case 1: traditional: should never see load_in_progress.
818 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
819
820 // case 3: bootstrap classloader: prevent futile classloading,
821 // wait on first requestor
822 if (class_loader.is_null()) {
823 SystemDictionary_lock->wait();
824 } else {
825 // case 2: traditional with broken classloader lock. wait on first
826 // requestor.
827 double_lock_wait(lockObject, THREAD);
828 }
829 // Check if classloading completed while we were waiting
830 InstanceKlass* check = find_class(d_hash, name, dictionary);
831 if (check != NULL) {
832 // Klass is already loaded, so just return it
833 k = check;
834 class_has_been_loaded = true;
835 }
836 // check if other thread failed to load and cleaned up
837 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
838 }
839 }
840 }
841 }
842 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
843 // case 4: parallelCapable: allow competing threads to try
844 // LOAD_INSTANCE in parallel
845
846 if (!throw_circularity_error && !class_has_been_loaded) {
847 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
848 load_instance_added = true;
849 // For class loaders that do not acquire the classloader object lock,
850 // if they did not catch another thread holding LOAD_INSTANCE,
851 // need a check analogous to the acquire ObjectLocker/find_class
852 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
853 // one final check if the load has already completed
854 // class loaders holding the ObjectLock shouldn't find the class here
855 InstanceKlass* check = find_class(d_hash, name, dictionary);
856 if (check != NULL) {
857 // Klass is already loaded, so return it after checking/adding protection domain
858 k = check;
859 class_has_been_loaded = true;
860 }
861 }
862 }
863
864 // must throw error outside of owning lock
865 if (throw_circularity_error) {
866 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
867 ResourceMark rm(THREAD);
868 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
869 }
870
871 if (!class_has_been_loaded) {
872
873 // Do actual loading
874 k = load_instance_class(name, class_loader, THREAD);
875
876 // If everything was OK (no exceptions, no null return value), and
877 // class_loader is NOT the defining loader, do a little more bookkeeping.
878 if (!HAS_PENDING_EXCEPTION && k != NULL &&
879 k->class_loader() != class_loader()) {
880
881 check_constraints(d_hash, k, class_loader, false, THREAD);
882
883 // Need to check for a PENDING_EXCEPTION again; check_constraints
884 // can throw but we may have to remove entry from the placeholder table below.
885 if (!HAS_PENDING_EXCEPTION) {
886 // Record dependency for non-parent delegation.
887 // This recording keeps the defining class loader of the klass (k) found
888 // from being unloaded while the initiating class loader is loaded
889 // even if the reference to the defining class loader is dropped
890 // before references to the initiating class loader.
891 loader_data->record_dependency(k);
892
893 { // Grabbing the Compile_lock prevents systemDictionary updates
894 // during compilations.
895 MutexLocker mu(THREAD, Compile_lock);
896 update_dictionary(d_hash, p_index, p_hash,
897 k, class_loader, THREAD);
898 }
899
900 if (JvmtiExport::should_post_class_load()) {
901 JvmtiExport::post_class_load(THREAD->as_Java_thread(), k);
902 }
903 }
904 }
905 } // load_instance_class
906
907 if (load_instance_added == true) {
908 // clean up placeholder entries for LOAD_INSTANCE success or error
909 // This brackets the SystemDictionary updates for both defining
910 // and initiating loaders
911 MutexLocker mu(THREAD, SystemDictionary_lock);
912 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
913 SystemDictionary_lock->notify_all();
914 }
915 }
916
917 if (HAS_PENDING_EXCEPTION || k == NULL) {
918 return NULL;
919 }
920 if (class_load_start_event.should_commit()) {
921 post_class_load_event(&class_load_start_event, k, loader_data);
922 }
923 #ifdef ASSERT
924 {
925 ClassLoaderData* loader_data = k->class_loader_data();
926 MutexLocker mu(THREAD, SystemDictionary_lock);
927 InstanceKlass* kk = find_class(name, loader_data);
928 assert(kk == k, "should be present in dictionary");
929 }
930 #endif
931
932 // return if the protection domain in NULL
933 if (protection_domain() == NULL) return k;
934
935 // Check the protection domain has the right access
936 if (dictionary->is_valid_protection_domain(d_hash, name,
937 protection_domain)) {
938 return k;
939 }
940
941 // Verify protection domain. If it fails an exception is thrown
942 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
943
944 return k;
945 }
946
947
948 // This routine does not lock the system dictionary.
949 //
950 // Since readers don't hold a lock, we must make sure that system
951 // dictionary entries are only removed at a safepoint (when only one
952 // thread is running), and are added to in a safe way (all links must
953 // be updated in an MT-safe manner).
954 //
955 // Callers should be aware that an entry could be added just after
956 // _dictionary->bucket(index) is read here, so the caller will not see
957 // the new entry.
958
959 Klass* SystemDictionary::find(Symbol* class_name,
960 Handle class_loader,
961 Handle protection_domain,
962 TRAPS) {
963
964 // The result of this call should be consistent with the result
965 // of the call to resolve_instance_class_or_null().
966 // See evaluation 6790209 and 4474172 for more details.
967 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
968 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
969
970 if (loader_data == NULL) {
971 // If the ClassLoaderData has not been setup,
972 // then the class loader has no entries in the dictionary.
973 return NULL;
974 }
975
976 Dictionary* dictionary = loader_data->dictionary();
977 unsigned int d_hash = dictionary->compute_hash(class_name);
978 return dictionary->find(d_hash, class_name,
979 protection_domain);
980 }
981
982
983 // Look for a loaded instance or array klass by name. Do not do any loading.
984 // return NULL in case of error.
985 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
986 Handle class_loader,
987 Handle protection_domain,
988 TRAPS) {
989 Klass* k = NULL;
990 assert(class_name != NULL, "class name must be non NULL");
991
992 if (Signature::is_array(class_name)) {
993 // The name refers to an array. Parse the name.
994 // dimension and object_key in FieldArrayInfo are assigned as a
995 // side-effect of this call
996 SignatureStream ss(class_name, false);
997 int ndims = ss.skip_array_prefix(); // skip all '['s
998 BasicType t = ss.type();
999 if (t != T_OBJECT) {
1000 k = Universe::typeArrayKlassObj(t);
1001 } else {
1002 k = SystemDictionary::find(ss.as_symbol(), class_loader, protection_domain, THREAD);
1003 }
1004 if (k != NULL) {
1005 k = k->array_klass_or_null(ndims);
1006 }
1007 } else {
1008 k = find(class_name, class_loader, protection_domain, THREAD);
1009 }
1010 return k;
1011 }
1012
1013 // Note: this method is much like resolve_from_stream, but
1014 // does not publish the classes via the SystemDictionary.
1015 // Handles Lookup.defineClass hidden, unsafe_DefineAnonymousClass
1016 // and redefineclasses. RedefinedClasses do not add to the class hierarchy.
1017 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1018 Handle class_loader,
1019 ClassFileStream* st,
1020 const ClassLoadInfo& cl_info,
1021 TRAPS) {
1022
1023 EventClassLoad class_load_start_event;
1024 ClassLoaderData* loader_data;
1025 bool is_unsafe_anon_class = cl_info.unsafe_anonymous_host() != NULL;
1026
1027 // - for unsafe anonymous class: create a new CLD whith a class holder that uses
1028 // the same class loader as the unsafe_anonymous_host.
1029 // - for hidden classes that are not strong: create a new CLD that has a class holder and
1030 // whose loader is the Lookup class's loader.
1031 // - for hidden class: add the class to the Lookup class's loader's CLD.
1032 if (is_unsafe_anon_class || cl_info.is_hidden()) {
1033 guarantee(!is_unsafe_anon_class || cl_info.unsafe_anonymous_host()->class_loader() == class_loader(),
1034 "should be NULL or the same");
1035 bool create_mirror_cld = is_unsafe_anon_class || !cl_info.is_strong_hidden();
1036 loader_data = register_loader(class_loader, create_mirror_cld);
1037 } else {
1038 loader_data = ClassLoaderData::class_loader_data(class_loader());
1039 }
1040
1041 assert(st != NULL, "invariant");
1042 assert(st->need_verify(), "invariant");
1043
1044 // Parse stream and create a klass.
1045 // Note that we do this even though this klass might
1046 // already be present in the SystemDictionary, otherwise we would not
1047 // throw potential ClassFormatErrors.
1048
1049 InstanceKlass* k = KlassFactory::create_from_stream(st,
1050 class_name,
1051 loader_data,
1052 cl_info,
1053 CHECK_NULL);
1054
1055 if ((cl_info.is_hidden() || is_unsafe_anon_class) && k != NULL) {
1056 // Hidden classes that are not strong and unsafe anonymous classes must update
1057 // ClassLoaderData holder so that they can be unloaded when the mirror is no
1058 // longer referenced.
1059 if (!cl_info.is_strong_hidden() || is_unsafe_anon_class) {
1060 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1061 }
1062
1063 {
1064 MutexLocker mu_r(THREAD, Compile_lock);
1065
1066 // Add to class hierarchy, initialize vtables, and do possible
1067 // deoptimizations.
1068 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1069 // But, do not add to dictionary.
1070 }
1071
1072 // Rewrite and patch constant pool here.
1073 k->link_class(CHECK_NULL);
1074 if (cl_info.cp_patches() != NULL) {
1075 k->constants()->patch_resolved_references(cl_info.cp_patches());
1076 }
1077
1078 // If it's anonymous, initialize it now, since nobody else will.
1079 if (is_unsafe_anon_class) {
1080 k->eager_initialize(CHECK_NULL);
1081 }
1082
1083 // notify jvmti
1084 if (JvmtiExport::should_post_class_load()) {
1085 JvmtiExport::post_class_load(THREAD->as_Java_thread(), k);
1086 }
1087 if (class_load_start_event.should_commit()) {
1088 post_class_load_event(&class_load_start_event, k, loader_data);
1089 }
1090 }
1091 assert(is_unsafe_anon_class || NULL == cl_info.cp_patches(),
1092 "cp_patches only found with unsafe_anonymous_host");
1093
1094 return k;
1095 }
1096
1097 // Add a klass to the system from a stream (called by jni_DefineClass and
1098 // JVM_DefineClass).
1099 // Note: class_name can be NULL. In that case we do not know the name of
1100 // the class until we have parsed the stream.
1101
1102 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1103 Handle class_loader,
1104 Handle protection_domain,
1105 ClassFileStream* st,
1106 TRAPS) {
1107
1108 HandleMark hm(THREAD);
1109
1110 // Classloaders that support parallelism, e.g. bootstrap classloader,
1111 // do not acquire lock here
1112 bool DoObjectLock = true;
1113 if (is_parallelCapable(class_loader)) {
1114 DoObjectLock = false;
1115 }
1116
1117 ClassLoaderData* loader_data = register_loader(class_loader);
1118
1119 // Make sure we are synchronized on the class loader before we proceed
1120 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1121 check_loader_lock_contention(lockObject, THREAD);
1122 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1123
1124 assert(st != NULL, "invariant");
1125
1126 // Parse the stream and create a klass.
1127 // Note that we do this even though this klass might
1128 // already be present in the SystemDictionary, otherwise we would not
1129 // throw potential ClassFormatErrors.
1130 InstanceKlass* k = NULL;
1131
1132 #if INCLUDE_CDS
1133 if (!DumpSharedSpaces) {
1134 k = SystemDictionaryShared::lookup_from_stream(class_name,
1135 class_loader,
1136 protection_domain,
1137 st,
1138 CHECK_NULL);
1139 }
1140 #endif
1141
1142 if (k == NULL) {
1143 if (st->buffer() == NULL) {
1144 return NULL;
1145 }
1146 ClassLoadInfo cl_info(protection_domain);
1147 k = KlassFactory::create_from_stream(st, class_name, loader_data, cl_info, CHECK_NULL);
1148 }
1149
1150 assert(k != NULL, "no klass created");
1151 Symbol* h_name = k->name();
1152 assert(class_name == NULL || class_name == h_name, "name mismatch");
1153
1154 // Add class just loaded
1155 // If a class loader supports parallel classloading handle parallel define requests
1156 // find_or_define_instance_class may return a different InstanceKlass
1157 if (is_parallelCapable(class_loader)) {
1158 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1159 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1160 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1161 assert(defined_k != NULL, "Should have a klass if there's no exception");
1162 loader_data->add_to_deallocate_list(k);
1163 k = defined_k;
1164 }
1165 } else {
1166 define_instance_class(k, THREAD);
1167 }
1168
1169 // If defining the class throws an exception register 'k' for cleanup.
1170 if (HAS_PENDING_EXCEPTION) {
1171 assert(k != NULL, "Must have an instance klass here!");
1172 loader_data->add_to_deallocate_list(k);
1173 return NULL;
1174 }
1175
1176 // Make sure we have an entry in the SystemDictionary on success
1177 debug_only( {
1178 MutexLocker mu(THREAD, SystemDictionary_lock);
1179
1180 Klass* check = find_class(h_name, k->class_loader_data());
1181 assert(check == k, "should be present in the dictionary");
1182 } );
1183
1184 return k;
1185 }
1186
1187 #if INCLUDE_CDS
1188 // Load a class for boot loader from the shared spaces. This also
1189 // forces the super class and all interfaces to be loaded.
1190 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1191 PackageEntry* pkg_entry,
1192 TRAPS) {
1193 assert(UseSharedSpaces, "Sanity check");
1194 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1195 if (ik != NULL && ik->is_shared_boot_class()) {
1196 return load_shared_class(ik, Handle(), Handle(), NULL, pkg_entry, THREAD);
1197 }
1198 return NULL;
1199 }
1200
1201 // Check if a shared class can be loaded by the specific classloader.
1202 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1203 InstanceKlass* ik,
1204 PackageEntry* pkg_entry,
1205 Handle class_loader, TRAPS) {
1206 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1207 "Cannot use sharing if java.base is patched");
1208
1209 // (1) Check if we are loading into the same loader as in dump time.
1210
1211 if (ik->is_shared_boot_class()) {
1212 if (class_loader() != NULL) {
1213 return false;
1214 }
1215 } else if (ik->is_shared_platform_class()) {
1216 if (class_loader() != java_platform_loader()) {
1217 return false;
1218 }
1219 } else if (ik->is_shared_app_class()) {
1220 if (class_loader() != java_system_loader()) {
1221 return false;
1222 }
1223 } else {
1224 // ik was loaded by a custom loader during dump time
1225 if (class_loader_data(class_loader)->is_builtin_class_loader_data()) {
1226 return false;
1227 } else {
1228 return true;
1229 }
1230 }
1231
1232 // (2) Check if we are loading into the same module from the same location as in dump time.
1233
1234 if (MetaspaceShared::use_optimized_module_handling()) {
1235 // Class visibility has not changed between dump time and run time, so a class
1236 // that was visible (and thus archived) during dump time is always visible during runtime.
1237 assert(SystemDictionary::is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader, THREAD),
1238 "visibility cannot change between dump time and runtime");
1239 return true;
1240 }
1241 return is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader, THREAD);
1242 }
1243
1244 bool SystemDictionary::is_shared_class_visible_impl(Symbol* class_name,
1245 InstanceKlass* ik,
1246 PackageEntry* pkg_entry,
1247 Handle class_loader, TRAPS) {
1248 int scp_index = ik->shared_classpath_index();
1249 assert(!ik->is_shared_unregistered_class(), "this function should be called for built-in classes only");
1250 assert(scp_index >= 0, "must be");
1251 SharedClassPathEntry* scp_entry = FileMapInfo::shared_path(scp_index);
1252 if (!Universe::is_module_initialized()) {
1253 assert(scp_entry != NULL && scp_entry->is_modules_image(),
1254 "Loading non-bootstrap classes before the module system is initialized");
1255 assert(class_loader.is_null(), "sanity");
1256 return true;
1257 }
1258
1259 ModuleEntry* mod_entry = (pkg_entry == NULL) ? NULL : pkg_entry->module();
1260 bool should_be_in_named_module = (mod_entry != NULL && mod_entry->is_named());
1261 bool was_archived_from_named_module = scp_entry->in_named_module();
1262 bool visible;
1263
1264 if (was_archived_from_named_module) {
1265 if (should_be_in_named_module) {
1266 // Is the module loaded from the same location as during dump time?
1267 visible = mod_entry->shared_path_index() == scp_index;
1268 if (visible) {
1269 assert(!mod_entry->is_patched(), "cannot load archived classes for patched module");
1270 }
1271 } else {
1272 // During dump time, this class was in a named module, but at run time, this class should be
1273 // in an unnamed module.
1274 visible = false;
1275 }
1276 } else {
1277 if (should_be_in_named_module) {
1278 // During dump time, this class was in an unnamed, but at run time, this class should be
1279 // in a named module.
1280 visible = false;
1281 } else {
1282 visible = true;
1283 }
1284 }
1285
1286 return visible;
1287 }
1288
1289 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1290 Handle class_loader, Handle protection_domain,
1291 bool is_superclass, TRAPS) {
1292 assert(super_type->is_shared(), "must be");
1293
1294 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1295 class_loader, protection_domain, is_superclass, CHECK_0);
1296 if (found == super_type) {
1297 return true;
1298 } else {
1299 // The dynamically resolved super type is not the same as the one we used during dump time,
1300 // so we cannot use the child class.
1301 return false;
1302 }
1303 }
1304
1305 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1306 Handle protection_domain, TRAPS) {
1307 // Check the superclass and interfaces. They must be the same
1308 // as in dump time, because the layout of <ik> depends on
1309 // the specific layout of ik->super() and ik->local_interfaces().
1310 //
1311 // If unexpected superclass or interfaces are found, we cannot
1312 // load <ik> from the shared archive.
1313
1314 if (ik->super() != NULL &&
1315 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1316 class_loader, protection_domain, true, THREAD)) {
1317 return false;
1318 }
1319
1320 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1321 int num_interfaces = interfaces->length();
1322 for (int index = 0; index < num_interfaces; index++) {
1323 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1324 return false;
1325 }
1326 }
1327
1328 return true;
1329 }
1330
1331 InstanceKlass* SystemDictionary::load_shared_lambda_proxy_class(InstanceKlass* ik,
1332 Handle class_loader,
1333 Handle protection_domain,
1334 PackageEntry* pkg_entry,
1335 TRAPS) {
1336 InstanceKlass* shared_nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1337 assert(shared_nest_host->is_shared(), "nest host must be in CDS archive");
1338 Symbol* cn = shared_nest_host->name();
1339 Klass *s = resolve_or_fail(cn, class_loader, protection_domain, true, CHECK_NULL);
1340 if (s != shared_nest_host) {
1341 // The dynamically resolved nest_host is not the same as the one we used during dump time,
1342 // so we cannot use ik.
1343 return NULL;
1344 } else {
1345 assert(s->is_shared(), "must be");
1346 }
1347
1348 // The lambda proxy class and its nest host have the same class loader and class loader data,
1349 // as verified in SystemDictionaryShared::add_lambda_proxy_class()
1350 assert(shared_nest_host->class_loader() == class_loader(), "mismatched class loader");
1351 assert(shared_nest_host->class_loader_data() == ClassLoaderData::class_loader_data(class_loader()), "mismatched class loader data");
1352 ik->set_nest_host(shared_nest_host, THREAD);
1353
1354 InstanceKlass* loaded_ik = load_shared_class(ik, class_loader, protection_domain, NULL, pkg_entry, CHECK_NULL);
1355
1356 assert(shared_nest_host->is_same_class_package(ik),
1357 "lambda proxy class and its nest host must be in the same package");
1358
1359 return loaded_ik;
1360 }
1361
1362 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1363 Handle class_loader,
1364 Handle protection_domain,
1365 const ClassFileStream *cfs,
1366 PackageEntry* pkg_entry,
1367 TRAPS) {
1368 assert(ik != NULL, "sanity");
1369 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1370 Symbol* class_name = ik->name();
1371
1372 bool visible = is_shared_class_visible(
1373 class_name, ik, pkg_entry, class_loader, CHECK_NULL);
1374 if (!visible) {
1375 return NULL;
1376 }
1377
1378 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1379 return NULL;
1380 }
1381
1382 InstanceKlass* new_ik = NULL;
1383 // CFLH check is skipped for VM hidden or anonymous classes (see KlassFactory::create_from_stream).
1384 // It will be skipped for shared VM hidden lambda proxy classes.
1385 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1386 new_ik = KlassFactory::check_shared_class_file_load_hook(
1387 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1388 }
1389 if (new_ik != NULL) {
1390 // The class is changed by CFLH. Return the new class. The shared class is
1391 // not used.
1392 return new_ik;
1393 }
1394
1395 // Adjust methods to recover missing data. They need addresses for
1396 // interpreter entry points and their default native method address
1397 // must be reset.
1398
1399 // Updating methods must be done under a lock so multiple
1400 // threads don't update these in parallel
1401 //
1402 // Shared classes are all currently loaded by either the bootstrap or
1403 // internal parallel class loaders, so this will never cause a deadlock
1404 // on a custom class loader lock.
1405
1406 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1407 {
1408 HandleMark hm(THREAD);
1409 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1410 check_loader_lock_contention(lockObject, THREAD);
1411 ObjectLocker ol(lockObject, THREAD, true);
1412 // prohibited package check assumes all classes loaded from archive call
1413 // restore_unshareable_info which calls ik->set_package()
1414 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1415 }
1416
1417 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1418 return ik;
1419 }
1420
1421 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1422 ik->print_class_load_logging(loader_data, NULL, NULL);
1423
1424 // For boot loader, ensure that GetSystemPackage knows that a class in this
1425 // package was loaded.
1426 if (loader_data->is_the_null_class_loader_data()) {
1427 int path_index = ik->shared_classpath_index();
1428 ik->set_classpath_index(path_index, THREAD);
1429 }
1430
1431 // notify a class loaded from shared object
1432 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1433
1434 ik->set_has_passed_fingerprint_check(false);
1435 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1436 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1437 uint64_t cds_fp = ik->get_stored_fingerprint();
1438 if (aot_fp != 0 && aot_fp == cds_fp) {
1439 // This class matches with a class saved in an AOT library
1440 ik->set_has_passed_fingerprint_check(true);
1441 } else {
1442 if (log_is_enabled(Info, class, fingerprint)) {
1443 ResourceMark rm(THREAD);
1444 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1445 }
1446 }
1447 }
1448 }
1449
1450 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1451 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1452 assert(klass->is_shared(), "Must be shared class");
1453 if (klass->class_loader_data() != NULL) {
1454 return;
1455 }
1456
1457 // add super and interfaces first
1458 Klass* super = klass->super();
1459 if (super != NULL && super->class_loader_data() == NULL) {
1460 assert(super->is_instance_klass(), "Super should be instance klass");
1461 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1462 }
1463
1464 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1465 for (int i = 0; i < ifs->length(); i++) {
1466 InstanceKlass* ik = ifs->at(i);
1467 if (ik->class_loader_data() == NULL) {
1468 quick_resolve(ik, loader_data, domain, CHECK);
1469 }
1470 }
1471
1472 klass->restore_unshareable_info(loader_data, domain, NULL, THREAD);
1473 load_shared_class_misc(klass, loader_data, CHECK);
1474 Dictionary* dictionary = loader_data->dictionary();
1475 unsigned int hash = dictionary->compute_hash(klass->name());
1476 dictionary->add_klass(hash, klass->name(), klass);
1477 add_to_hierarchy(klass, CHECK);
1478 assert(klass->is_loaded(), "Must be in at least loaded state");
1479 }
1480 #endif // INCLUDE_CDS
1481
1482 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1483
1484 if (class_loader.is_null()) {
1485 ResourceMark rm(THREAD);
1486 PackageEntry* pkg_entry = NULL;
1487 bool search_only_bootloader_append = false;
1488 ClassLoaderData *loader_data = class_loader_data(class_loader);
1489
1490 // Find the package in the boot loader's package entry table.
1491 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1492 if (pkg_name != NULL) {
1493 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1494 }
1495
1496 // Prior to attempting to load the class, enforce the boot loader's
1497 // visibility boundaries.
1498 if (!Universe::is_module_initialized()) {
1499 // During bootstrapping, prior to module initialization, any
1500 // class attempting to be loaded must be checked against the
1501 // java.base packages in the boot loader's PackageEntryTable.
1502 // No class outside of java.base is allowed to be loaded during
1503 // this bootstrapping window.
1504 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1505 // Class is either in the unnamed package or in
1506 // a named package within the unnamed module. Either
1507 // case is outside of java.base, do not attempt to
1508 // load the class post java.base definition. If
1509 // java.base has not been defined, let the class load
1510 // and its package will be checked later by
1511 // ModuleEntryTable::verify_javabase_packages.
1512 if (ModuleEntryTable::javabase_defined()) {
1513 return NULL;
1514 }
1515 } else {
1516 // Check that the class' package is defined within java.base.
1517 ModuleEntry* mod_entry = pkg_entry->module();
1518 Symbol* mod_entry_name = mod_entry->name();
1519 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1520 return NULL;
1521 }
1522 }
1523 } else {
1524 // After the module system has been initialized, check if the class'
1525 // package is in a module defined to the boot loader.
1526 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1527 // Class is either in the unnamed package, in a named package
1528 // within a module not defined to the boot loader or in a
1529 // a named package within the unnamed module. In all cases,
1530 // limit visibility to search for the class only in the boot
1531 // loader's append path.
1532 if (!ClassLoader::has_bootclasspath_append()) {
1533 // If there is no bootclasspath append entry, no need to continue
1534 // searching.
1535 return NULL;
1536 }
1537 search_only_bootloader_append = true;
1538 }
1539 }
1540
1541 // Prior to bootstrapping's module initialization, never load a class outside
1542 // of the boot loader's module path
1543 assert(Universe::is_module_initialized() ||
1544 !search_only_bootloader_append,
1545 "Attempt to load a class outside of boot loader's module path");
1546
1547 // Search for classes in the CDS archive.
1548 InstanceKlass* k = NULL;
1549
1550 #if INCLUDE_CDS
1551 if (UseSharedSpaces)
1552 {
1553 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1554 k = load_shared_boot_class(class_name, pkg_entry, THREAD);
1555 }
1556 #endif
1557
1558 if (k == NULL) {
1559 // Use VM class loader
1560 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1561 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1562 }
1563
1564 // find_or_define_instance_class may return a different InstanceKlass
1565 if (k != NULL) {
1566 InstanceKlass* defined_k =
1567 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1568 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1569 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1570 assert(defined_k != NULL, "Should have a klass if there's no exception");
1571 loader_data->add_to_deallocate_list(k);
1572 k = defined_k;
1573 } else if (HAS_PENDING_EXCEPTION) {
1574 loader_data->add_to_deallocate_list(k);
1575 return NULL;
1576 }
1577 }
1578 return k;
1579 } else {
1580 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1581 ResourceMark rm(THREAD);
1582
1583 JavaThread* jt = THREAD->as_Java_thread();
1584
1585 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1586 ClassLoader::perf_app_classload_selftime(),
1587 ClassLoader::perf_app_classload_count(),
1588 jt->get_thread_stat()->perf_recursion_counts_addr(),
1589 jt->get_thread_stat()->perf_timers_addr(),
1590 PerfClassTraceTime::CLASS_LOAD);
1591
1592 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1593 // Translate to external class name format, i.e., convert '/' chars to '.'
1594 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1595
1596 JavaValue result(T_OBJECT);
1597
1598 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1599
1600 // Call public unsynchronized loadClass(String) directly for all class loaders.
1601 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1602 // acquire a class-name based lock rather than the class loader object lock.
1603 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1604 JavaCalls::call_virtual(&result,
1605 class_loader,
1606 spec_klass,
1607 vmSymbols::loadClass_name(),
1608 vmSymbols::string_class_signature(),
1609 string,
1610 CHECK_NULL);
1611
1612 assert(result.get_type() == T_OBJECT, "just checking");
1613 oop obj = (oop) result.get_jobject();
1614
1615 // Primitive classes return null since forName() can not be
1616 // used to obtain any of the Class objects representing primitives or void
1617 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1618 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1619 // For user defined Java class loaders, check that the name returned is
1620 // the same as that requested. This check is done for the bootstrap
1621 // loader when parsing the class file.
1622 if (class_name == k->name()) {
1623 return k;
1624 }
1625 }
1626 // Class is not found or has the wrong name, return NULL
1627 return NULL;
1628 }
1629 }
1630
1631 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1632 EventClassDefine event;
1633 if (event.should_commit()) {
1634 event.set_definedClass(k);
1635 event.set_definingClassLoader(def_cld);
1636 event.commit();
1637 }
1638 }
1639
1640 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1641
1642 HandleMark hm(THREAD);
1643 ClassLoaderData* loader_data = k->class_loader_data();
1644 Handle class_loader_h(THREAD, loader_data->class_loader());
1645
1646 // for bootstrap and other parallel classloaders don't acquire lock,
1647 // use placeholder token
1648 // If a parallelCapable class loader calls define_instance_class instead of
1649 // find_or_define_instance_class to get here, we have a timing
1650 // hole with systemDictionary updates and check_constraints
1651 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1652 assert(ObjectSynchronizer::current_thread_holds_lock(THREAD->as_Java_thread(),
1653 compute_loader_lock_object(class_loader_h, THREAD)),
1654 "define called without lock");
1655 }
1656
1657 // Check class-loading constraints. Throw exception if violation is detected.
1658 // Grabs and releases SystemDictionary_lock
1659 // The check_constraints/find_class call and update_dictionary sequence
1660 // must be "atomic" for a specific class/classloader pair so we never
1661 // define two different instanceKlasses for that class/classloader pair.
1662 // Existing classloaders will call define_instance_class with the
1663 // classloader lock held
1664 // Parallel classloaders will call find_or_define_instance_class
1665 // which will require a token to perform the define class
1666 Symbol* name_h = k->name();
1667 Dictionary* dictionary = loader_data->dictionary();
1668 unsigned int d_hash = dictionary->compute_hash(name_h);
1669 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1670
1671 // Register class just loaded with class loader (placed in ArrayList)
1672 // Note we do this before updating the dictionary, as this can
1673 // fail with an OutOfMemoryError (if it does, we will *not* put this
1674 // class in the dictionary and will not update the class hierarchy).
1675 // JVMTI FollowReferences needs to find the classes this way.
1676 if (k->class_loader() != NULL) {
1677 methodHandle m(THREAD, Universe::loader_addClass_method());
1678 JavaValue result(T_VOID);
1679 JavaCallArguments args(class_loader_h);
1680 args.push_oop(Handle(THREAD, k->java_mirror()));
1681 JavaCalls::call(&result, m, &args, CHECK);
1682 }
1683
1684 // Add the new class. We need recompile lock during update of CHA.
1685 {
1686 unsigned int p_hash = placeholders()->compute_hash(name_h);
1687 int p_index = placeholders()->hash_to_index(p_hash);
1688
1689 MutexLocker mu_r(THREAD, Compile_lock);
1690
1691 // Add to class hierarchy, initialize vtables, and do possible
1692 // deoptimizations.
1693 add_to_hierarchy(k, CHECK); // No exception, but can block
1694
1695 // Add to systemDictionary - so other classes can see it.
1696 // Grabs and releases SystemDictionary_lock
1697 update_dictionary(d_hash, p_index, p_hash,
1698 k, class_loader_h, THREAD);
1699 }
1700 k->eager_initialize(THREAD);
1701
1702 // notify jvmti
1703 if (JvmtiExport::should_post_class_load()) {
1704 JvmtiExport::post_class_load(THREAD->as_Java_thread(), k);
1705 }
1706 post_class_define_event(k, loader_data);
1707 }
1708
1709 // Support parallel classloading
1710 // All parallel class loaders, including bootstrap classloader
1711 // lock a placeholder entry for this class/class_loader pair
1712 // to allow parallel defines of different classes for this class loader
1713 // With AllowParallelDefine flag==true, in case they do not synchronize around
1714 // FindLoadedClass/DefineClass, calls, we check for parallel
1715 // loading for them, wait if a defineClass is in progress
1716 // and return the initial requestor's results
1717 // This flag does not apply to the bootstrap classloader.
1718 // With AllowParallelDefine flag==false, call through to define_instance_class
1719 // which will throw LinkageError: duplicate class definition.
1720 // False is the requested default.
1721 // For better performance, the class loaders should synchronize
1722 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1723 // potentially waste time reading and parsing the bytestream.
1724 // Note: VM callers should ensure consistency of k/class_name,class_loader
1725 // Be careful when modifying this code: once you have run
1726 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1727 // you need to find_and_remove it before returning.
1728 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1729 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1730 InstanceKlass* k, TRAPS) {
1731
1732 Symbol* name_h = k->name(); // passed in class_name may be null
1733 ClassLoaderData* loader_data = class_loader_data(class_loader);
1734 Dictionary* dictionary = loader_data->dictionary();
1735
1736 unsigned int d_hash = dictionary->compute_hash(name_h);
1737
1738 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1739 unsigned int p_hash = placeholders()->compute_hash(name_h);
1740 int p_index = placeholders()->hash_to_index(p_hash);
1741 PlaceholderEntry* probe;
1742
1743 {
1744 MutexLocker mu(THREAD, SystemDictionary_lock);
1745 // First check if class already defined
1746 if (is_parallelDefine(class_loader)) {
1747 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1748 if (check != NULL) {
1749 return check;
1750 }
1751 }
1752
1753 // Acquire define token for this class/classloader
1754 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1755 // Wait if another thread defining in parallel
1756 // All threads wait - even those that will throw duplicate class: otherwise
1757 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1758 // if other thread has not finished updating dictionary
1759 while (probe->definer() != NULL) {
1760 SystemDictionary_lock->wait();
1761 }
1762 // Only special cases allow parallel defines and can use other thread's results
1763 // Other cases fall through, and may run into duplicate defines
1764 // caught by finding an entry in the SystemDictionary
1765 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1766 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1767 SystemDictionary_lock->notify_all();
1768 #ifdef ASSERT
1769 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1770 assert(check != NULL, "definer missed recording success");
1771 #endif
1772 return probe->instance_klass();
1773 } else {
1774 // This thread will define the class (even if earlier thread tried and had an error)
1775 probe->set_definer(THREAD);
1776 }
1777 }
1778
1779 define_instance_class(k, THREAD);
1780
1781 Handle linkage_exception = Handle(); // null handle
1782
1783 // definer must notify any waiting threads
1784 {
1785 MutexLocker mu(THREAD, SystemDictionary_lock);
1786 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1787 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1788 if (probe != NULL) {
1789 if (HAS_PENDING_EXCEPTION) {
1790 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1791 CLEAR_PENDING_EXCEPTION;
1792 } else {
1793 probe->set_instance_klass(k);
1794 }
1795 probe->set_definer(NULL);
1796 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1797 SystemDictionary_lock->notify_all();
1798 }
1799 }
1800
1801 // Can't throw exception while holding lock due to rank ordering
1802 if (linkage_exception() != NULL) {
1803 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1804 }
1805
1806 return k;
1807 }
1808
1809 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1810 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1811 if (class_loader.is_null()) {
1812 return Handle(THREAD, _system_loader_lock_obj.resolve());
1813 } else {
1814 return class_loader;
1815 }
1816 }
1817
1818 // This method is added to check how often we have to wait to grab loader
1819 // lock. The results are being recorded in the performance counters defined in
1820 // ClassLoader::_sync_systemLoaderLockContentionRate and
1821 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1822 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1823 if (!UsePerfData) {
1824 return;
1825 }
1826
1827 assert(!loader_lock.is_null(), "NULL lock object");
1828
1829 if (ObjectSynchronizer::query_lock_ownership(THREAD->as_Java_thread(), loader_lock)
1830 == ObjectSynchronizer::owner_other) {
1831 // contention will likely happen, so increment the corresponding
1832 // contention counter.
1833 if (loader_lock() == _system_loader_lock_obj.resolve()) {
1834 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1835 } else {
1836 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1837 }
1838 }
1839 }
1840
1841 // ----------------------------------------------------------------------------
1842 // Lookup
1843
1844 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1845 Symbol* class_name,
1846 Dictionary* dictionary) {
1847 assert_locked_or_safepoint(SystemDictionary_lock);
1848 int index = dictionary->hash_to_index(hash);
1849 return dictionary->find_class(index, hash, class_name);
1850 }
1851
1852
1853 // Basic find on classes in the midst of being loaded
1854 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1855 ClassLoaderData* loader_data) {
1856 assert_locked_or_safepoint(SystemDictionary_lock);
1857 unsigned int p_hash = placeholders()->compute_hash(class_name);
1858 int p_index = placeholders()->hash_to_index(p_hash);
1859 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1860 }
1861
1862
1863 // Used for assertions and verification only
1864 // Precalculating the hash and index is an optimization because there are many lookups
1865 // before adding the class.
1866 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1867 assert_locked_or_safepoint(SystemDictionary_lock);
1868 #ifndef ASSERT
1869 guarantee(VerifyBeforeGC ||
1870 VerifyDuringGC ||
1871 VerifyBeforeExit ||
1872 VerifyDuringStartup ||
1873 VerifyAfterGC, "too expensive");
1874 #endif
1875
1876 Dictionary* dictionary = loader_data->dictionary();
1877 unsigned int d_hash = dictionary->compute_hash(class_name);
1878 return find_class(d_hash, class_name, dictionary);
1879 }
1880
1881
1882 // ----------------------------------------------------------------------------
1883 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1884 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1885 // before a new class is used.
1886
1887 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1888 assert(k != NULL, "just checking");
1889 if (Universe::is_fully_initialized()) {
1890 assert_locked_or_safepoint(Compile_lock);
1891 }
1892
1893 k->set_init_state(InstanceKlass::loaded);
1894 // make sure init_state store is already done.
1895 // The compiler reads the hierarchy outside of the Compile_lock.
1896 // Access ordering is used to add to hierarchy.
1897
1898 // Link into hierachy.
1899 k->append_to_sibling_list(); // add to superklass/sibling list
1900 k->process_interfaces(THREAD); // handle all "implements" declarations
1901
1902 // Now flush all code that depended on old class hierarchy.
1903 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1904 if (Universe::is_fully_initialized()) {
1905 CodeCache::flush_dependents_on(k);
1906 }
1907 }
1908
1909 // ----------------------------------------------------------------------------
1910 // GC support
1911
1912 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1913 // Note: anonymous classes are not in the SD.
1914 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1915
1916 bool unloading_occurred;
1917 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1918 {
1919 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1920 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1921 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1922 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1923 if (unloading_occurred) {
1924 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1925 JFR_ONLY(Jfr::on_unloading_classes();)
1926
1927 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1928 ClassLoaderDataGraph::clean_module_and_package_info();
1929 constraints()->purge_loader_constraints();
1930 resolution_errors()->purge_resolution_errors();
1931 }
1932 }
1933
1934 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1935
1936 if (unloading_occurred) {
1937 SymbolTable::trigger_cleanup();
1938
1939 // Oops referenced by the protection domain cache table may get unreachable independently
1940 // of the class loader (eg. cached protection domain oops). So we need to
1941 // explicitly unlink them here.
1942 // All protection domain oops are linked to the caller class, so if nothing
1943 // unloads, this is not needed.
1944 _pd_cache_table->trigger_cleanup();
1945 }
1946
1947 return unloading_occurred;
1948 }
1949
1950 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1951 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1952 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1953 it->push(well_known_klass_addr((WKID)id));
1954 }
1955 }
1956
1957 void SystemDictionary::methods_do(void f(Method*)) {
1958 // Walk methods in loaded classes
1959 MutexLocker ml(ClassLoaderDataGraph_lock);
1960 ClassLoaderDataGraph::methods_do(f);
1961 // Walk method handle intrinsics
1962 invoke_method_table()->methods_do(f);
1963 }
1964
1965 // ----------------------------------------------------------------------------
1966 // Initialization
1967
1968 void SystemDictionary::initialize(TRAPS) {
1969 // Allocate arrays
1970 _placeholders = new PlaceholderTable(_placeholder_table_size);
1971 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1972 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1973 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1974 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1975
1976 // Allocate private object used as system class loader lock
1977 oop lock_obj = oopFactory::new_intArray(0, CHECK);
1978 _system_loader_lock_obj = OopHandle(Universe::vm_global(), lock_obj);
1979
1980 // Initialize basic classes
1981 resolve_well_known_classes(CHECK);
1982 }
1983
1984 // Compact table of directions on the initialization of klasses:
1985 static const short wk_init_info[] = {
1986 #define WK_KLASS_INIT_INFO(name, symbol) \
1987 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1988
1989 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1990 #undef WK_KLASS_INIT_INFO
1991 0
1992 };
1993
1994 #ifdef ASSERT
1995 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1996 int sid;
1997 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1998 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1999 if (class_name == symbol) {
2000 return true;
2001 }
2002 }
2003 return false;
2004 }
2005
2006 bool SystemDictionary::is_well_known_klass(Klass* k) {
2007 return is_well_known_klass(k->name());
2008 }
2009 #endif
2010
2011 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
2012 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2013 int sid = wk_init_info[id - FIRST_WKID];
2014 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2015 InstanceKlass** klassp = &_well_known_klasses[id];
2016
2017 #if INCLUDE_CDS
2018 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
2019 InstanceKlass* k = *klassp;
2020 assert(k->is_shared_boot_class(), "must be");
2021
2022 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
2023 quick_resolve(k, loader_data, Handle(), CHECK_false);
2024 return true;
2025 }
2026 #endif // INCLUDE_CDS
2027
2028 if (!is_wk_klass_loaded(*klassp)) {
2029 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
2030 (*klassp) = InstanceKlass::cast(k);
2031 }
2032 return ((*klassp) != NULL);
2033 }
2034
2035 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2036 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2037 for (int id = (int)start_id; id < (int)limit_id; id++) {
2038 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2039 resolve_wk_klass((WKID)id, CHECK);
2040 }
2041
2042 // move the starting value forward to the limit:
2043 start_id = limit_id;
2044 }
2045
2046 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2047 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
2048
2049 // Create the ModuleEntry for java.base. This call needs to be done here,
2050 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2051 ClassLoader::classLoader_init2(CHECK);
2052
2053 // Preload commonly used klasses
2054 WKID scan = FIRST_WKID;
2055 // first do Object, then String, Class
2056 #if INCLUDE_CDS
2057 if (UseSharedSpaces) {
2058 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2059
2060 // It's unsafe to access the archived heap regions before they
2061 // are fixed up, so we must do the fixup as early as possible
2062 // before the archived java objects are accessed by functions
2063 // such as java_lang_Class::restore_archived_mirror and
2064 // ConstantPool::restore_unshareable_info (restores the archived
2065 // resolved_references array object).
2066 //
2067 // HeapShared::fixup_mapped_heap_regions() fills the empty
2068 // spaces in the archived heap regions and may use
2069 // SystemDictionary::Object_klass(), so we can do this only after
2070 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2071 // call. No mirror objects are accessed/restored in the above call.
2072 // Mirrors are restored after java.lang.Class is loaded.
2073 HeapShared::fixup_mapped_heap_regions();
2074
2075 // Initialize the constant pool for the Object_class
2076 assert(Object_klass()->is_shared(), "must be");
2077 Object_klass()->constants()->restore_unshareable_info(CHECK);
2078 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2079 } else
2080 #endif
2081 {
2082 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2083 }
2084
2085 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2086
2087 java_lang_Object::register_natives(CHECK);
2088
2089 // Calculate offsets for String and Class classes since they are loaded and
2090 // can be used after this point.
2091 java_lang_String::compute_offsets();
2092 java_lang_Class::compute_offsets();
2093
2094 // Fixup mirrors for classes loaded before java.lang.Class.
2095 Universe::initialize_basic_type_mirrors(CHECK);
2096 Universe::fixup_mirrors(CHECK);
2097
2098 // do a bunch more:
2099 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2100
2101 // The offsets for jlr.Reference must be computed before
2102 // InstanceRefKlass::update_nonstatic_oop_maps is called. That function uses
2103 // the offsets to remove the referent and discovered fields from the oop maps,
2104 // as they are treated in a special way by the GC. Removing these oops from the
2105 // oop maps must be done before the usual subclasses of jlr.Reference are loaded.
2106 java_lang_ref_Reference::compute_offsets();
2107
2108 // Preload ref klasses and set reference types
2109 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2110 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2111
2112 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2113 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2114 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2115 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2116 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2117
2118 // JSR 292 classes
2119 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2120 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2121 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2122 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2123 WKID last = WKID_LIMIT;
2124 resolve_wk_klasses_until(last, scan, CHECK);
2125
2126 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2127 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2128 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2129 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2130 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2131 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2132 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2133 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2134 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2135 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2136
2137 if (DiagnoseSyncOnPrimitiveWrappers != 0) {
2138 for (int i = T_BOOLEAN; i < T_LONG + 1; i++) {
2139 assert(_box_klasses[i] != NULL, "NULL box class");
2140 _box_klasses[i]->set_is_box();
2141 _box_klasses[i]->set_prototype_header(markWord::prototype());
2142 }
2143 }
2144
2145 #ifdef ASSERT
2146 if (UseSharedSpaces) {
2147 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2148 "All well known classes must be resolved in JVMTI early phase"));
2149 for (int i = FIRST_WKID; i < last; i++) {
2150 InstanceKlass* k = _well_known_klasses[i];
2151 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2152 }
2153 }
2154 #endif
2155 }
2156
2157 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2158 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2159 BasicType SystemDictionary::box_klass_type(Klass* k) {
2160 assert(k != NULL, "");
2161 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2162 if (_box_klasses[i] == k)
2163 return (BasicType)i;
2164 }
2165 return T_OBJECT;
2166 }
2167
2168 // Constraints on class loaders. The details of the algorithm can be
2169 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2170 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2171 // that the dictionary needs to maintain a set of contraints that
2172 // must be satisfied by all classes in the dictionary.
2173 // if defining is true, then LinkageError if already in dictionary
2174 // if initiating loader, then ok if InstanceKlass matches existing entry
2175
2176 void SystemDictionary::check_constraints(unsigned int d_hash,
2177 InstanceKlass* k,
2178 Handle class_loader,
2179 bool defining,
2180 TRAPS) {
2181 ResourceMark rm(THREAD);
2182 stringStream ss;
2183 bool throwException = false;
2184
2185 {
2186 Symbol *name = k->name();
2187 ClassLoaderData *loader_data = class_loader_data(class_loader);
2188
2189 MutexLocker mu(THREAD, SystemDictionary_lock);
2190
2191 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2192 if (check != NULL) {
2193 // If different InstanceKlass - duplicate class definition,
2194 // else - ok, class loaded by a different thread in parallel.
2195 // We should only have found it if it was done loading and ok to use.
2196 // The dictionary only holds instance classes, placeholders
2197 // also hold array classes.
2198
2199 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2200 if ((defining == true) || (k != check)) {
2201 throwException = true;
2202 ss.print("loader %s", loader_data->loader_name_and_id());
2203 ss.print(" attempted duplicate %s definition for %s. (%s)",
2204 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2205 } else {
2206 return;
2207 }
2208 }
2209
2210 #ifdef ASSERT
2211 Symbol* ph_check = find_placeholder(name, loader_data);
2212 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2213 #endif
2214
2215 if (throwException == false) {
2216 if (constraints()->check_or_update(k, class_loader, name) == false) {
2217 throwException = true;
2218 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2219 ss.print(" wants to load %s %s.",
2220 k->external_kind(), k->external_name());
2221 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2222 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2223 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2224 existing_klass->external_kind(),
2225 existing_klass->class_loader_data()->loader_name_and_id(),
2226 existing_klass->class_in_module_of_loader(false, true));
2227 } else {
2228 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2229 }
2230 }
2231 }
2232 }
2233
2234 // Throw error now if needed (cannot throw while holding
2235 // SystemDictionary_lock because of rank ordering)
2236 if (throwException == true) {
2237 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2238 }
2239 }
2240
2241 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2242 // have been called.
2243 void SystemDictionary::update_dictionary(unsigned int d_hash,
2244 int p_index, unsigned int p_hash,
2245 InstanceKlass* k,
2246 Handle class_loader,
2247 TRAPS) {
2248 // Compile_lock prevents systemDictionary updates during compilations
2249 assert_locked_or_safepoint(Compile_lock);
2250 Symbol* name = k->name();
2251 ClassLoaderData *loader_data = class_loader_data(class_loader);
2252
2253 {
2254 MutexLocker mu1(THREAD, SystemDictionary_lock);
2255
2256 // Make a new dictionary entry.
2257 Dictionary* dictionary = loader_data->dictionary();
2258 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2259 if (sd_check == NULL) {
2260 dictionary->add_klass(d_hash, name, k);
2261 }
2262 #ifdef ASSERT
2263 sd_check = find_class(d_hash, name, dictionary);
2264 assert (sd_check != NULL, "should have entry in dictionary");
2265 // Note: there may be a placeholder entry: for circularity testing
2266 // or for parallel defines
2267 #endif
2268 SystemDictionary_lock->notify_all();
2269 }
2270 }
2271
2272
2273 // Try to find a class name using the loader constraints. The
2274 // loader constraints might know about a class that isn't fully loaded
2275 // yet and these will be ignored.
2276 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2277 Symbol* class_name, Handle class_loader, TRAPS) {
2278
2279 // First see if it has been loaded directly.
2280 // Force the protection domain to be null. (This removes protection checks.)
2281 Handle no_protection_domain;
2282 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2283 no_protection_domain, CHECK_NULL);
2284 if (klass != NULL)
2285 return klass;
2286
2287 // Now look to see if it has been loaded elsewhere, and is subject to
2288 // a loader constraint that would require this loader to return the
2289 // klass that is already loaded.
2290 if (Signature::is_array(class_name)) {
2291 // For array classes, their Klass*s are not kept in the
2292 // constraint table. The element Klass*s are.
2293 SignatureStream ss(class_name, false);
2294 int ndims = ss.skip_array_prefix(); // skip all '['s
2295 BasicType t = ss.type();
2296 if (t != T_OBJECT) {
2297 klass = Universe::typeArrayKlassObj(t);
2298 } else {
2299 MutexLocker mu(THREAD, SystemDictionary_lock);
2300 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2301 }
2302 // If element class already loaded, allocate array klass
2303 if (klass != NULL) {
2304 klass = klass->array_klass_or_null(ndims);
2305 }
2306 } else {
2307 MutexLocker mu(THREAD, SystemDictionary_lock);
2308 // Non-array classes are easy: simply check the constraint table.
2309 klass = constraints()->find_constrained_klass(class_name, class_loader);
2310 }
2311
2312 return klass;
2313 }
2314
2315 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2316 Klass* klass_being_linked,
2317 Handle class_loader1,
2318 Handle class_loader2,
2319 Thread* THREAD) {
2320 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2321 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2322
2323 Symbol* constraint_name = NULL;
2324
2325 if (!Signature::is_array(class_name)) {
2326 constraint_name = class_name;
2327 } else {
2328 // For array classes, their Klass*s are not kept in the
2329 // constraint table. The element classes are.
2330 SignatureStream ss(class_name, false);
2331 ss.skip_array_prefix(); // skip all '['s
2332 if (!ss.has_envelope()) {
2333 return true; // primitive types always pass
2334 }
2335 constraint_name = ss.as_symbol();
2336 // Increment refcount to keep constraint_name alive after
2337 // SignatureStream is destructed. It will be decremented below
2338 // before returning.
2339 constraint_name->increment_refcount();
2340 }
2341
2342 Dictionary* dictionary1 = loader_data1->dictionary();
2343 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2344
2345 Dictionary* dictionary2 = loader_data2->dictionary();
2346 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2347
2348 {
2349 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2350 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2351 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2352 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2353 klass2, class_loader2);
2354 #if INCLUDE_CDS
2355 if (Arguments::is_dumping_archive() && klass_being_linked != NULL &&
2356 !klass_being_linked->is_shared()) {
2357 SystemDictionaryShared::record_linking_constraint(constraint_name,
2358 InstanceKlass::cast(klass_being_linked),
2359 class_loader1, class_loader2, THREAD);
2360 }
2361 #endif // INCLUDE_CDS
2362 if (Signature::is_array(class_name)) {
2363 constraint_name->decrement_refcount();
2364 }
2365 return result;
2366 }
2367 }
2368
2369 // Add entry to resolution error table to record the error when the first
2370 // attempt to resolve a reference to a class has failed.
2371 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2372 Symbol* error, Symbol* message) {
2373 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2374 int index = resolution_errors()->hash_to_index(hash);
2375 {
2376 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2377 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2378 }
2379 }
2380
2381 // Delete a resolution error for RedefineClasses for a constant pool is going away
2382 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2383 resolution_errors()->delete_entry(pool);
2384 }
2385
2386 // Lookup resolution error table. Returns error if found, otherwise NULL.
2387 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2388 Symbol** message) {
2389 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2390 int index = resolution_errors()->hash_to_index(hash);
2391 {
2392 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2393 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2394 if (entry != NULL) {
2395 *message = entry->message();
2396 return entry->error();
2397 } else {
2398 return NULL;
2399 }
2400 }
2401 }
2402
2403 // Add an entry to resolution error table to record an error in resolving or
2404 // validating a nest host. This is used to construct informative error
2405 // messages when IllegalAccessError's occur. If an entry already exists it will
2406 // be updated with the nest host error message.
2407 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
2408 int which,
2409 const char* message) {
2410 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2411 int index = resolution_errors()->hash_to_index(hash);
2412 {
2413 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2414 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2415 if (entry != NULL) {
2416 assert(entry->nest_host_error() == NULL, "Nest host error message already set!");
2417 entry->set_nest_host_error(message);
2418 } else {
2419 resolution_errors()->add_entry(index, hash, pool, which, message);
2420 }
2421 }
2422 }
2423
2424 // Lookup any nest host error
2425 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
2426 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2427 int index = resolution_errors()->hash_to_index(hash);
2428 {
2429 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2430 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2431 if (entry != NULL) {
2432 return entry->nest_host_error();
2433 } else {
2434 return NULL;
2435 }
2436 }
2437 }
2438
2439
2440 // Signature constraints ensure that callers and callees agree about
2441 // the meaning of type names in their signatures. This routine is the
2442 // intake for constraints. It collects them from several places:
2443 //
2444 // * LinkResolver::resolve_method (if check_access is true) requires
2445 // that the resolving class (the caller) and the defining class of
2446 // the resolved method (the callee) agree on each type in the
2447 // method's signature.
2448 //
2449 // * LinkResolver::resolve_interface_method performs exactly the same
2450 // checks.
2451 //
2452 // * LinkResolver::resolve_field requires that the constant pool
2453 // attempting to link to a field agree with the field's defining
2454 // class about the type of the field signature.
2455 //
2456 // * klassVtable::initialize_vtable requires that, when a class
2457 // overrides a vtable entry allocated by a superclass, that the
2458 // overriding method (i.e., the callee) agree with the superclass
2459 // on each type in the method's signature.
2460 //
2461 // * klassItable::initialize_itable requires that, when a class fills
2462 // in its itables, for each non-abstract method installed in an
2463 // itable, the method (i.e., the callee) agree with the interface
2464 // on each type in the method's signature.
2465 //
2466 // All those methods have a boolean (check_access, checkconstraints)
2467 // which turns off the checks. This is used from specialized contexts
2468 // such as bootstrapping, dumping, and debugging.
2469 //
2470 // No direct constraint is placed between the class and its
2471 // supertypes. Constraints are only placed along linked relations
2472 // between callers and callees. When a method overrides or implements
2473 // an abstract method in a supertype (superclass or interface), the
2474 // constraints are placed as if the supertype were the caller to the
2475 // overriding method. (This works well, since callers to the
2476 // supertype have already established agreement between themselves and
2477 // the supertype.) As a result of all this, a class can disagree with
2478 // its supertype about the meaning of a type name, as long as that
2479 // class neither calls a relevant method of the supertype, nor is
2480 // called (perhaps via an override) from the supertype.
2481 //
2482 //
2483 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
2484 //
2485 // Make sure all class components (including arrays) in the given
2486 // signature will be resolved to the same class in both loaders.
2487 // Returns the name of the type that failed a loader constraint check, or
2488 // NULL if no constraint failed. No exception except OOME is thrown.
2489 // Arrays are not added to the loader constraint table, their elements are.
2490 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2491 Klass* klass_being_linked,
2492 Handle loader1, Handle loader2,
2493 bool is_method, TRAPS) {
2494 // Nothing to do if loaders are the same.
2495 if (loader1() == loader2()) {
2496 return NULL;
2497 }
2498
2499 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2500 if (ss.is_reference()) {
2501 Symbol* sig = ss.as_symbol();
2502 // Note: In the future, if template-like types can take
2503 // arguments, we will want to recognize them and dig out class
2504 // names hiding inside the argument lists.
2505 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2, THREAD)) {
2506 return sig;
2507 }
2508 }
2509 }
2510 return NULL;
2511 }
2512
2513 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2514 Symbol* signature,
2515 TRAPS) {
2516 methodHandle empty;
2517 assert(MethodHandles::is_signature_polymorphic(iid) &&
2518 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2519 iid != vmIntrinsics::_invokeGeneric,
2520 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2521
2522 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2523 int index = invoke_method_table()->hash_to_index(hash);
2524 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2525 methodHandle m;
2526 if (spe == NULL || spe->method() == NULL) {
2527 spe = NULL;
2528 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2529 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2530 if (!Arguments::is_interpreter_only()) {
2531 // Generate a compiled form of the MH intrinsic.
2532 AdapterHandlerLibrary::create_native_wrapper(m);
2533 // Check if have the compiled code.
2534 if (!m->has_compiled_code()) {
2535 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2536 "Out of space in CodeCache for method handle intrinsic");
2537 }
2538 }
2539 // Now grab the lock. We might have to throw away the new method,
2540 // if a racing thread has managed to install one at the same time.
2541 {
2542 MutexLocker ml(THREAD, SystemDictionary_lock);
2543 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2544 if (spe == NULL)
2545 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2546 if (spe->method() == NULL)
2547 spe->set_method(m());
2548 }
2549 }
2550
2551 assert(spe != NULL && spe->method() != NULL, "");
2552 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2553 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2554 "MH intrinsic invariant");
2555 return spe->method();
2556 }
2557
2558 // Helper for unpacking the return value from linkMethod and linkCallSite.
2559 static Method* unpack_method_and_appendix(Handle mname,
2560 Klass* accessing_klass,
2561 objArrayHandle appendix_box,
2562 Handle* appendix_result,
2563 TRAPS) {
2564 if (mname.not_null()) {
2565 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2566 if (m != NULL) {
2567 oop appendix = appendix_box->obj_at(0);
2568 LogTarget(Info, methodhandles) lt;
2569 if (lt.develop_is_enabled()) {
2570 ResourceMark rm(THREAD);
2571 LogStream ls(lt);
2572 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2573 m->print_on(&ls);
2574 if (appendix != NULL) { ls.print("appendix = "); appendix->print_on(&ls); }
2575 ls.cr();
2576 }
2577
2578 (*appendix_result) = Handle(THREAD, appendix);
2579 // the target is stored in the cpCache and if a reference to this
2580 // MemberName is dropped we need a way to make sure the
2581 // class_loader containing this method is kept alive.
2582 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2583 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2584 this_key->record_dependency(m->method_holder());
2585 return mh();
2586 }
2587 }
2588 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2589 }
2590
2591 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2592 Symbol* name,
2593 Symbol* signature,
2594 Klass* accessing_klass,
2595 Handle *appendix_result,
2596 TRAPS) {
2597 assert(THREAD->can_call_java() ,"");
2598 Handle method_type =
2599 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2600
2601 int ref_kind = JVM_REF_invokeVirtual;
2602 oop name_oop = StringTable::intern(name, CHECK_NULL);
2603 Handle name_str (THREAD, name_oop);
2604 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2605 assert(appendix_box->obj_at(0) == NULL, "");
2606
2607 // This should not happen. JDK code should take care of that.
2608 if (accessing_klass == NULL || method_type.is_null()) {
2609 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2610 }
2611
2612 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2613 JavaCallArguments args;
2614 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2615 args.push_int(ref_kind);
2616 args.push_oop(Handle(THREAD, klass->java_mirror()));
2617 args.push_oop(name_str);
2618 args.push_oop(method_type);
2619 args.push_oop(appendix_box);
2620 JavaValue result(T_OBJECT);
2621 JavaCalls::call_static(&result,
2622 SystemDictionary::MethodHandleNatives_klass(),
2623 vmSymbols::linkMethod_name(),
2624 vmSymbols::linkMethod_signature(),
2625 &args, CHECK_NULL);
2626 Handle mname(THREAD, (oop) result.get_jobject());
2627 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2628 }
2629
2630 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2631 // We must ensure that all class loaders everywhere will reach this class, for any client.
2632 // This is a safe bet for public classes in java.lang, such as Object and String.
2633 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2634 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2635 static bool is_always_visible_class(oop mirror) {
2636 Klass* klass = java_lang_Class::as_Klass(mirror);
2637 if (klass->is_objArray_klass()) {
2638 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2639 }
2640 if (klass->is_typeArray_klass()) {
2641 return true; // primitive array
2642 }
2643 assert(klass->is_instance_klass(), "%s", klass->external_name());
2644 return klass->is_public() &&
2645 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2646 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2647 }
2648
2649 // Find or construct the Java mirror (java.lang.Class instance) for
2650 // the given field type signature, as interpreted relative to the
2651 // given class loader. Handles primitives, void, references, arrays,
2652 // and all other reflectable types, except method types.
2653 // N.B. Code in reflection should use this entry point.
2654 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2655 Klass* accessing_klass,
2656 Handle class_loader,
2657 Handle protection_domain,
2658 SignatureStream::FailureMode failure_mode,
2659 TRAPS) {
2660 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2661 "one or the other, or perhaps neither");
2662
2663 // What we have here must be a valid field descriptor,
2664 // and all valid field descriptors are supported.
2665 // Produce the same java.lang.Class that reflection reports.
2666 if (accessing_klass != NULL) {
2667 class_loader = Handle(THREAD, accessing_klass->class_loader());
2668 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2669 }
2670 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2671 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2672 if (mirror_oop == NULL) {
2673 return Handle(); // report failure this way
2674 }
2675 Handle mirror(THREAD, mirror_oop);
2676
2677 if (accessing_klass != NULL) {
2678 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2679 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2680 if (sel_klass != NULL) {
2681 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2682 }
2683 }
2684 return mirror;
2685 }
2686
2687
2688 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2689 // signature, as interpreted relative to the given class loader.
2690 // Because of class loader constraints, all method handle usage must be
2691 // consistent with this loader.
2692 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2693 Klass* accessing_klass,
2694 TRAPS) {
2695 Handle empty;
2696 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2697 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2698 int index = invoke_method_table()->hash_to_index(hash);
2699 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2700 if (spe != NULL && spe->method_type() != NULL) {
2701 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2702 return Handle(THREAD, spe->method_type());
2703 } else if (!THREAD->can_call_java()) {
2704 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2705 return Handle(); // do not attempt from within compiler, unless it was cached
2706 }
2707
2708 Handle class_loader, protection_domain;
2709 if (accessing_klass != NULL) {
2710 class_loader = Handle(THREAD, accessing_klass->class_loader());
2711 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2712 }
2713 bool can_be_cached = true;
2714 int npts = ArgumentCount(signature).size();
2715 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2716 int arg = 0;
2717 Handle rt; // the return type from the signature
2718 ResourceMark rm(THREAD);
2719 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2720 oop mirror = NULL;
2721 if (can_be_cached) {
2722 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2723 mirror = ss.as_java_mirror(Handle(), Handle(),
2724 SignatureStream::ReturnNull, CHECK_(empty));
2725 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2726 // Fall back to accessing_klass context.
2727 can_be_cached = false;
2728 }
2729 }
2730 if (!can_be_cached) {
2731 // Resolve, throwing a real error if it doesn't work.
2732 mirror = ss.as_java_mirror(class_loader, protection_domain,
2733 SignatureStream::NCDFError, CHECK_(empty));
2734 }
2735 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2736 if (ss.at_return_type())
2737 rt = Handle(THREAD, mirror);
2738 else
2739 pts->obj_at_put(arg++, mirror);
2740
2741 // Check accessibility.
2742 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2743 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2744 mirror = NULL; // safety
2745 // Emulate ConstantPool::verify_constant_pool_resolve.
2746 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2747 }
2748 }
2749 assert(arg == npts, "");
2750
2751 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2752 JavaCallArguments args(Handle(THREAD, rt()));
2753 args.push_oop(pts);
2754 JavaValue result(T_OBJECT);
2755 JavaCalls::call_static(&result,
2756 SystemDictionary::MethodHandleNatives_klass(),
2757 vmSymbols::findMethodHandleType_name(),
2758 vmSymbols::findMethodHandleType_signature(),
2759 &args, CHECK_(empty));
2760 Handle method_type(THREAD, (oop) result.get_jobject());
2761
2762 if (can_be_cached) {
2763 // We can cache this MethodType inside the JVM.
2764 MutexLocker ml(THREAD, SystemDictionary_lock);
2765 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2766 if (spe == NULL)
2767 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2768 if (spe->method_type() == NULL) {
2769 spe->set_method_type(method_type());
2770 }
2771 }
2772
2773 // report back to the caller with the MethodType
2774 return method_type;
2775 }
2776
2777 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2778 Klass* accessing_klass,
2779 TRAPS) {
2780 Handle empty;
2781 ResourceMark rm(THREAD);
2782 SignatureStream ss(signature, /*is_method=*/ false);
2783 if (!ss.is_done()) {
2784 Handle class_loader, protection_domain;
2785 if (accessing_klass != NULL) {
2786 class_loader = Handle(THREAD, accessing_klass->class_loader());
2787 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2788 }
2789 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2790 ss.next();
2791 if (ss.is_done()) {
2792 return Handle(THREAD, mirror);
2793 }
2794 }
2795 return empty;
2796 }
2797
2798 // Ask Java code to find or construct a method handle constant.
2799 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2800 int ref_kind, //e.g., JVM_REF_invokeVirtual
2801 Klass* callee,
2802 Symbol* name,
2803 Symbol* signature,
2804 TRAPS) {
2805 Handle empty;
2806 if (caller == NULL) {
2807 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2808 }
2809 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2810 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2811
2812 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2813 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2814 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2815 java_lang_invoke_MemberName::set_name (mname(), name_str());
2816 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2817 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2818
2819 if (ref_kind == JVM_REF_invokeVirtual &&
2820 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2821 // Skip resolution for public signature polymorphic methods such as
2822 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2823 // They require appendix argument which MemberName resolution doesn't handle.
2824 // There's special logic on JDK side to handle them
2825 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2826 } else {
2827 MethodHandles::resolve_MemberName(mname, caller, 0, false /*speculative_resolve*/, CHECK_(empty));
2828 }
2829
2830 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2831 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2832
2833 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2834 JavaCallArguments args;
2835 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2836 args.push_int(ref_kind);
2837 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2838 args.push_oop(name_str);
2839 args.push_oop(type);
2840 JavaValue result(T_OBJECT);
2841 JavaCalls::call_static(&result,
2842 SystemDictionary::MethodHandleNatives_klass(),
2843 vmSymbols::linkMethodHandleConstant_name(),
2844 vmSymbols::linkMethodHandleConstant_signature(),
2845 &args, CHECK_(empty));
2846 return Handle(THREAD, (oop) result.get_jobject());
2847 }
2848
2849 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2850 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2851 // with linkage results being stored back into the bootstrap specifier.
2852 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2853 // Resolve the bootstrap specifier, its name, type, and static arguments
2854 bootstrap_specifier.resolve_bsm(CHECK);
2855
2856 // This should not happen. JDK code should take care of that.
2857 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2858 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2859 }
2860
2861 bool is_indy = bootstrap_specifier.is_method_call();
2862 objArrayHandle appendix_box;
2863 if (is_indy) {
2864 // Some method calls may require an appendix argument. Arrange to receive it.
2865 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2866 assert(appendix_box->obj_at(0) == NULL, "");
2867 }
2868
2869 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2870 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2871 JavaCallArguments args;
2872 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2873 args.push_int(bootstrap_specifier.bss_index());
2874 args.push_oop(bootstrap_specifier.bsm());
2875 args.push_oop(bootstrap_specifier.name_arg());
2876 args.push_oop(bootstrap_specifier.type_arg());
2877 args.push_oop(bootstrap_specifier.arg_values());
2878 if (is_indy) {
2879 args.push_oop(appendix_box);
2880 }
2881 JavaValue result(T_OBJECT);
2882 JavaCalls::call_static(&result,
2883 SystemDictionary::MethodHandleNatives_klass(),
2884 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2885 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2886 &args, CHECK);
2887
2888 Handle value(THREAD, (oop) result.get_jobject());
2889 if (is_indy) {
2890 Handle appendix;
2891 Method* method = unpack_method_and_appendix(value,
2892 bootstrap_specifier.caller(),
2893 appendix_box,
2894 &appendix, CHECK);
2895 methodHandle mh(THREAD, method);
2896 bootstrap_specifier.set_resolved_method(mh, appendix);
2897 } else {
2898 bootstrap_specifier.set_resolved_value(value);
2899 }
2900
2901 // sanity check
2902 assert(bootstrap_specifier.is_resolved() ||
2903 (bootstrap_specifier.is_method_call() &&
2904 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2905 }
2906
2907 // Protection domain cache table handling
2908
2909 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2910 return _pd_cache_table->get(protection_domain);
2911 }
2912
2913 ClassLoaderData* SystemDictionary::class_loader_data(Handle class_loader) {
2914 return ClassLoaderData::class_loader_data(class_loader());
2915 }
2916
2917 bool SystemDictionary::is_wk_klass_loaded(InstanceKlass* klass) {
2918 return !(klass == NULL || !klass->is_loaded());
2919 }
2920
2921 bool SystemDictionary::is_nonpublic_Object_method(Method* m) {
2922 assert(m != NULL, "Unexpected NULL Method*");
2923 return !m->is_public() && m->method_holder() == SystemDictionary::Object_klass();
2924 }
2925
2926 // ----------------------------------------------------------------------------
2927
2928 void SystemDictionary::print_on(outputStream *st) {
2929 CDS_ONLY(SystemDictionaryShared::print_on(st));
2930 GCMutexLocker mu(SystemDictionary_lock);
2931
2932 ClassLoaderDataGraph::print_dictionary(st);
2933
2934 // Placeholders
2935 placeholders()->print_on(st);
2936 st->cr();
2937
2938 // loader constraints - print under SD_lock
2939 constraints()->print_on(st);
2940 st->cr();
2941
2942 _pd_cache_table->print_on(st);
2943 st->cr();
2944 }
2945
2946 void SystemDictionary::print() { print_on(tty); }
2947
2948 void SystemDictionary::verify() {
2949 guarantee(constraints() != NULL,
2950 "Verify of loader constraints failed");
2951 guarantee(placeholders()->number_of_entries() >= 0,
2952 "Verify of placeholders failed");
2953
2954 GCMutexLocker mu(SystemDictionary_lock);
2955
2956 // Verify dictionary
2957 ClassLoaderDataGraph::verify_dictionary();
2958
2959 placeholders()->verify();
2960
2961 // Verify constraint table
2962 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2963 constraints()->verify(placeholders());
2964
2965 _pd_cache_table->verify();
2966 }
2967
2968 void SystemDictionary::dump(outputStream *st, bool verbose) {
2969 assert_locked_or_safepoint(SystemDictionary_lock);
2970 if (verbose) {
2971 print_on(st);
2972 } else {
2973 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2974 ClassLoaderDataGraph::print_table_statistics(st);
2975 placeholders()->print_table_statistics(st, "Placeholder Table");
2976 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2977 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2978 }
2979 }
2980
2981 TableStatistics SystemDictionary::placeholders_statistics() {
2982 MutexLocker ml(SystemDictionary_lock);
2983 return placeholders()->statistics_calculate();
2984 }
2985
2986 TableStatistics SystemDictionary::loader_constraints_statistics() {
2987 MutexLocker ml(SystemDictionary_lock);
2988 return constraints()->statistics_calculate();
2989 }
2990
2991 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2992 MutexLocker ml(SystemDictionary_lock);
2993 return pd_cache_table()->statistics_calculate();
2994 }
2995
2996 // Utility for dumping dictionaries.
2997 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2998 DCmdWithParser(output, heap),
2999 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3000 "BOOLEAN", false, "false") {
3001 _dcmdparser.add_dcmd_option(&_verbose);
3002 }
3003
3004 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3005 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3006 _verbose.value());
3007 VMThread::execute(&dumper);
3008 }
3009
3010 int SystemDictionaryDCmd::num_arguments() {
3011 ResourceMark rm;
3012 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3013 if (dcmd != NULL) {
3014 DCmdMark mark(dcmd);
3015 return dcmd->_dcmdparser.num_arguments();
3016 } else {
3017 return 0;
3018 }
3019 }