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