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 void SystemDictionary::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
1255 // 1) the class is intended for a custom loader and should not be loaded by boot/platform/app loaders
1256 // or
1257 // 2) the class is a hidden lambda proxy class which would be loaded by boot/platform/app loaders
1258 if (loader_data->is_builtin_class_loader_data()) {
1259 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1260 return false;
1261 } else {
1262 return true;
1263 }
1264 } else {
1265 return true;
1266 }
1267 }
1268 SharedClassPathEntry* ent =
1269 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1270 if (!Universe::is_module_initialized()) {
1271 assert(ent != NULL && ent->is_modules_image(),
1272 "Loading non-bootstrap classes before the module system is initialized");
1273 assert(class_loader.is_null(), "sanity");
1274 return true;
1275 }
1276 // Get the pkg_entry from the classloader
1277 ModuleEntry* mod_entry = NULL;
1278 TempNewSymbol pkg_name = pkg_entry != NULL ? pkg_entry->name() :
1279 ClassLoader::package_from_class_name(class_name);
1280 if (pkg_name != NULL) {
1281 if (loader_data != NULL) {
1282 if (pkg_entry != NULL) {
1283 mod_entry = pkg_entry->module();
1284 // If the archived class is from a module that has been patched at runtime,
1285 // the class cannot be loaded from the archive.
1286 if (mod_entry != NULL && mod_entry->is_patched()) {
1287 return false;
1288 }
1289 }
1290 }
1291 }
1292
1293 if (class_loader.is_null()) {
1294 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1295 // The NULL classloader can load archived class originated from the
1296 // "modules" jimage and the -Xbootclasspath/a. For class from the
1297 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1298 // by the NULL classloader.
1299 if (mod_entry != NULL) {
1300 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1301 // ModuleEntry's location agrees with the archived class' origination.
1302 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1303 return true; // Module class from the "module" jimage
1304 }
1305 }
1306
1307 // If the archived class is not from the "module" jimage, the class can be
1308 // loaded by the NULL classloader if
1309 //
1310 // 1. the class is from the unamed package
1311 // 2. or, the class is not from a module defined in the NULL classloader
1312 // 3. or, the class is from an unamed module
1313 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1314 // the class is from the -Xbootclasspath/a
1315 if (pkg_name == NULL ||
1316 pkg_entry == NULL ||
1317 pkg_entry->in_unnamed_module()) {
1318 assert(mod_entry == NULL ||
1319 mod_entry == loader_data->unnamed_module(),
1320 "the unnamed module is not defined in the classloader");
1321 return true;
1322 }
1323 }
1324 return false;
1325 } else {
1326 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1327 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1328 return res;
1329 }
1330 }
1331
1332 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1333 Handle class_loader, Handle protection_domain,
1334 bool is_superclass, TRAPS) {
1335 assert(super_type->is_shared(), "must be");
1336
1337 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1338 class_loader, protection_domain, is_superclass, CHECK_0);
1339 if (found == super_type) {
1340 return true;
1341 } else {
1342 // The dynamically resolved super type is not the same as the one we used during dump time,
1343 // so we cannot use the child class.
1344 return false;
1345 }
1346 }
1347
1348 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1349 Handle protection_domain, TRAPS) {
1350 // Check the superclass and interfaces. They must be the same
1351 // as in dump time, because the layout of <ik> depends on
1352 // the specific layout of ik->super() and ik->local_interfaces().
1353 //
1354 // If unexpected superclass or interfaces are found, we cannot
1355 // load <ik> from the shared archive.
1356
1357 if (ik->super() != NULL &&
1358 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1359 class_loader, protection_domain, true, THREAD)) {
1360 return false;
1361 }
1362
1363 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1364 int num_interfaces = interfaces->length();
1365 for (int index = 0; index < num_interfaces; index++) {
1366 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1367 return false;
1368 }
1369 }
1370
1371 return true;
1372 }
1373
1374 InstanceKlass* SystemDictionary::load_shared_lambda_proxy_class(InstanceKlass* ik,
1375 Handle class_loader,
1376 Handle protection_domain,
1377 PackageEntry* pkg_entry,
1378 TRAPS) {
1379 InstanceKlass* shared_nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1380 assert(shared_nest_host->is_shared(), "nest host must be in CDS archive");
1381 Symbol* cn = shared_nest_host->name();
1382 Klass *s = resolve_or_fail(cn, class_loader, protection_domain, true, CHECK_NULL);
1383 if (s != shared_nest_host) {
1384 // The dynamically resolved nest_host is not the same as the one we used during dump time,
1385 // so we cannot use ik.
1386 return NULL;
1387 } else {
1388 assert(s->is_shared(), "must be");
1389 }
1390
1391 // The lambda proxy class and its nest host have the same class loader and class loader data,
1392 // as verified in SystemDictionaryShared::add_lambda_proxy_class()
1393 assert(shared_nest_host->class_loader() == class_loader(), "mismatched class loader");
1394 assert(shared_nest_host->class_loader_data() == ClassLoaderData::class_loader_data(class_loader()), "mismatched class loader data");
1395 ik->set_nest_host(shared_nest_host, THREAD);
1396
1397 InstanceKlass* loaded_ik = load_shared_class(ik, class_loader, protection_domain, NULL, pkg_entry, CHECK_NULL);
1398
1399 assert(shared_nest_host->is_same_class_package(ik),
1400 "lambda proxy class and its nest host must be in the same package");
1401
1402 return loaded_ik;
1403 }
1404
1405 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1406 Handle class_loader,
1407 Handle protection_domain,
1408 const ClassFileStream *cfs,
1409 PackageEntry* pkg_entry,
1410 TRAPS) {
1411 assert(ik != NULL, "sanity");
1412 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1413 Symbol* class_name = ik->name();
1414
1415 bool visible = is_shared_class_visible(
1416 class_name, ik, pkg_entry, class_loader, CHECK_NULL);
1417 if (!visible) {
1418 return NULL;
1419 }
1420
1421 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1422 return NULL;
1423 }
1424
1425 InstanceKlass* new_ik = NULL;
1426 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1427 new_ik = KlassFactory::check_shared_class_file_load_hook(
1428 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1429 }
1430 if (new_ik != NULL) {
1431 // The class is changed by CFLH. Return the new class. The shared class is
1432 // not used.
1433 return new_ik;
1434 }
1435
1436 // Adjust methods to recover missing data. They need addresses for
1437 // interpreter entry points and their default native method address
1438 // must be reset.
1439
1440 // Updating methods must be done under a lock so multiple
1441 // threads don't update these in parallel
1442 //
1443 // Shared classes are all currently loaded by either the bootstrap or
1444 // internal parallel class loaders, so this will never cause a deadlock
1445 // on a custom class loader lock.
1446
1447 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1448 {
1449 HandleMark hm(THREAD);
1450 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1451 check_loader_lock_contention(lockObject, THREAD);
1452 ObjectLocker ol(lockObject, THREAD, true);
1453 // prohibited package check assumes all classes loaded from archive call
1454 // restore_unshareable_info which calls ik->set_package()
1455 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1456 }
1457
1458 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1459 return ik;
1460 }
1461
1462 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1463 ik->print_class_load_logging(loader_data, NULL, NULL);
1464
1465 // For boot loader, ensure that GetSystemPackage knows that a class in this
1466 // package was loaded.
1467 if (loader_data->is_the_null_class_loader_data()) {
1468 int path_index = ik->shared_classpath_index();
1469 if (path_index < 0) {
1470 if (SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1471 InstanceKlass* nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1472 path_index = nest_host->shared_classpath_index();
1473 }
1474 }
1475 ik->set_classpath_index(path_index, THREAD);
1476 }
1477
1478 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1479 // Only dump the classes that can be stored into CDS archive
1480 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1481 ResourceMark rm(THREAD);
1482 classlist_file->print_cr("%s", ik->name()->as_C_string());
1483 classlist_file->flush();
1484 }
1485 }
1486
1487 // notify a class loaded from shared object
1488 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1489
1490 ik->set_has_passed_fingerprint_check(false);
1491 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1492 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1493 uint64_t cds_fp = ik->get_stored_fingerprint();
1494 if (aot_fp != 0 && aot_fp == cds_fp) {
1495 // This class matches with a class saved in an AOT library
1496 ik->set_has_passed_fingerprint_check(true);
1497 } else {
1498 if (log_is_enabled(Info, class, fingerprint)) {
1499 ResourceMark rm(THREAD);
1500 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1501 }
1502 }
1503 }
1504 }
1505
1506 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1507 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1508 assert(klass->is_shared(), "Must be shared class");
1509 if (klass->class_loader_data() != NULL) {
1510 return;
1511 }
1512
1513 // add super and interfaces first
1514 Klass* super = klass->super();
1515 if (super != NULL && super->class_loader_data() == NULL) {
1516 assert(super->is_instance_klass(), "Super should be instance klass");
1517 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1518 }
1519
1520 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1521 for (int i = 0; i < ifs->length(); i++) {
1522 InstanceKlass* ik = ifs->at(i);
1523 if (ik->class_loader_data() == NULL) {
1524 quick_resolve(ik, loader_data, domain, CHECK);
1525 }
1526 }
1527
1528 klass->restore_unshareable_info(loader_data, domain, NULL, THREAD);
1529 load_shared_class_misc(klass, loader_data, CHECK);
1530 Dictionary* dictionary = loader_data->dictionary();
1531 unsigned int hash = dictionary->compute_hash(klass->name());
1532 dictionary->add_klass(hash, klass->name(), klass);
1533 add_to_hierarchy(klass, CHECK);
1534 assert(klass->is_loaded(), "Must be in at least loaded state");
1535 }
1536 #endif // INCLUDE_CDS
1537
1538 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1539
1540 if (class_loader.is_null()) {
1541 ResourceMark rm(THREAD);
1542 PackageEntry* pkg_entry = NULL;
1543 bool search_only_bootloader_append = false;
1544 ClassLoaderData *loader_data = class_loader_data(class_loader);
1545
1546 // Find the package in the boot loader's package entry table.
1547 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1548 if (pkg_name != NULL) {
1549 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1550 }
1551
1552 // Prior to attempting to load the class, enforce the boot loader's
1553 // visibility boundaries.
1554 if (!Universe::is_module_initialized()) {
1555 // During bootstrapping, prior to module initialization, any
1556 // class attempting to be loaded must be checked against the
1557 // java.base packages in the boot loader's PackageEntryTable.
1558 // No class outside of java.base is allowed to be loaded during
1559 // this bootstrapping window.
1560 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1561 // Class is either in the unnamed package or in
1562 // a named package within the unnamed module. Either
1563 // case is outside of java.base, do not attempt to
1564 // load the class post java.base definition. If
1565 // java.base has not been defined, let the class load
1566 // and its package will be checked later by
1567 // ModuleEntryTable::verify_javabase_packages.
1568 if (ModuleEntryTable::javabase_defined()) {
1569 return NULL;
1570 }
1571 } else {
1572 // Check that the class' package is defined within java.base.
1573 ModuleEntry* mod_entry = pkg_entry->module();
1574 Symbol* mod_entry_name = mod_entry->name();
1575 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1576 return NULL;
1577 }
1578 }
1579 } else {
1580 // After the module system has been initialized, check if the class'
1581 // package is in a module defined to the boot loader.
1582 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1583 // Class is either in the unnamed package, in a named package
1584 // within a module not defined to the boot loader or in a
1585 // a named package within the unnamed module. In all cases,
1586 // limit visibility to search for the class only in the boot
1587 // loader's append path.
1588 if (!ClassLoader::has_bootclasspath_append()) {
1589 // If there is no bootclasspath append entry, no need to continue
1590 // searching.
1591 return NULL;
1592 }
1593 search_only_bootloader_append = true;
1594 }
1595 }
1596
1597 // Prior to bootstrapping's module initialization, never load a class outside
1598 // of the boot loader's module path
1599 assert(Universe::is_module_initialized() ||
1600 !search_only_bootloader_append,
1601 "Attempt to load a class outside of boot loader's module path");
1602
1603 // Search for classes in the CDS archive.
1604 InstanceKlass* k = NULL;
1605 {
1606 #if INCLUDE_CDS
1607 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1608 k = load_shared_boot_class(class_name, pkg_entry, THREAD);
1609 #endif
1610 }
1611
1612 if (k == NULL) {
1613 // Use VM class loader
1614 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1615 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1616 }
1617
1618 // find_or_define_instance_class may return a different InstanceKlass
1619 if (k != NULL) {
1620 InstanceKlass* defined_k =
1621 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1622 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1623 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1624 assert(defined_k != NULL, "Should have a klass if there's no exception");
1625 loader_data->add_to_deallocate_list(k);
1626 k = defined_k;
1627 } else if (HAS_PENDING_EXCEPTION) {
1628 loader_data->add_to_deallocate_list(k);
1629 return NULL;
1630 }
1631 }
1632 return k;
1633 } else {
1634 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1635 ResourceMark rm(THREAD);
1636
1637 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1638 JavaThread* jt = (JavaThread*) THREAD;
1639
1640 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1641 ClassLoader::perf_app_classload_selftime(),
1642 ClassLoader::perf_app_classload_count(),
1643 jt->get_thread_stat()->perf_recursion_counts_addr(),
1644 jt->get_thread_stat()->perf_timers_addr(),
1645 PerfClassTraceTime::CLASS_LOAD);
1646
1647 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1648 // Translate to external class name format, i.e., convert '/' chars to '.'
1649 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1650
1651 JavaValue result(T_OBJECT);
1652
1653 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1654
1655 // Call public unsynchronized loadClass(String) directly for all class loaders.
1656 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1657 // acquire a class-name based lock rather than the class loader object lock.
1658 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1659 JavaCalls::call_virtual(&result,
1660 class_loader,
1661 spec_klass,
1662 vmSymbols::loadClass_name(),
1663 vmSymbols::string_class_signature(),
1664 string,
1665 CHECK_NULL);
1666
1667 assert(result.get_type() == T_OBJECT, "just checking");
1668 oop obj = (oop) result.get_jobject();
1669
1670 // Primitive classes return null since forName() can not be
1671 // used to obtain any of the Class objects representing primitives or void
1672 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1673 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1674 // For user defined Java class loaders, check that the name returned is
1675 // the same as that requested. This check is done for the bootstrap
1676 // loader when parsing the class file.
1677 if (class_name == k->name()) {
1678 return k;
1679 }
1680 }
1681 // Class is not found or has the wrong name, return NULL
1682 return NULL;
1683 }
1684 }
1685
1686 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1687 EventClassDefine event;
1688 if (event.should_commit()) {
1689 event.set_definedClass(k);
1690 event.set_definingClassLoader(def_cld);
1691 event.commit();
1692 }
1693 }
1694
1695 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1696
1697 HandleMark hm(THREAD);
1698 ClassLoaderData* loader_data = k->class_loader_data();
1699 Handle class_loader_h(THREAD, loader_data->class_loader());
1700
1701 // for bootstrap and other parallel classloaders don't acquire lock,
1702 // use placeholder token
1703 // If a parallelCapable class loader calls define_instance_class instead of
1704 // find_or_define_instance_class to get here, we have a timing
1705 // hole with systemDictionary updates and check_constraints
1706 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1707 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1708 compute_loader_lock_object(class_loader_h, THREAD)),
1709 "define called without lock");
1710 }
1711
1712 // Check class-loading constraints. Throw exception if violation is detected.
1713 // Grabs and releases SystemDictionary_lock
1714 // The check_constraints/find_class call and update_dictionary sequence
1715 // must be "atomic" for a specific class/classloader pair so we never
1716 // define two different instanceKlasses for that class/classloader pair.
1717 // Existing classloaders will call define_instance_class with the
1718 // classloader lock held
1719 // Parallel classloaders will call find_or_define_instance_class
1720 // which will require a token to perform the define class
1721 Symbol* name_h = k->name();
1722 Dictionary* dictionary = loader_data->dictionary();
1723 unsigned int d_hash = dictionary->compute_hash(name_h);
1724 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1725
1726 // Register class just loaded with class loader (placed in ArrayList)
1727 // Note we do this before updating the dictionary, as this can
1728 // fail with an OutOfMemoryError (if it does, we will *not* put this
1729 // class in the dictionary and will not update the class hierarchy).
1730 // JVMTI FollowReferences needs to find the classes this way.
1731 if (k->class_loader() != NULL) {
1732 methodHandle m(THREAD, Universe::loader_addClass_method());
1733 JavaValue result(T_VOID);
1734 JavaCallArguments args(class_loader_h);
1735 args.push_oop(Handle(THREAD, k->java_mirror()));
1736 JavaCalls::call(&result, m, &args, CHECK);
1737 }
1738
1739 // Add the new class. We need recompile lock during update of CHA.
1740 {
1741 unsigned int p_hash = placeholders()->compute_hash(name_h);
1742 int p_index = placeholders()->hash_to_index(p_hash);
1743
1744 MutexLocker mu_r(THREAD, Compile_lock);
1745
1746 // Add to class hierarchy, initialize vtables, and do possible
1747 // deoptimizations.
1748 add_to_hierarchy(k, CHECK); // No exception, but can block
1749
1750 // Add to systemDictionary - so other classes can see it.
1751 // Grabs and releases SystemDictionary_lock
1752 update_dictionary(d_hash, p_index, p_hash,
1753 k, class_loader_h, THREAD);
1754 }
1755 k->eager_initialize(THREAD);
1756
1757 // notify jvmti
1758 if (JvmtiExport::should_post_class_load()) {
1759 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1760 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1761
1762 }
1763 post_class_define_event(k, loader_data);
1764 }
1765
1766 // Support parallel classloading
1767 // All parallel class loaders, including bootstrap classloader
1768 // lock a placeholder entry for this class/class_loader pair
1769 // to allow parallel defines of different classes for this class loader
1770 // With AllowParallelDefine flag==true, in case they do not synchronize around
1771 // FindLoadedClass/DefineClass, calls, we check for parallel
1772 // loading for them, wait if a defineClass is in progress
1773 // and return the initial requestor's results
1774 // This flag does not apply to the bootstrap classloader.
1775 // With AllowParallelDefine flag==false, call through to define_instance_class
1776 // which will throw LinkageError: duplicate class definition.
1777 // False is the requested default.
1778 // For better performance, the class loaders should synchronize
1779 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1780 // potentially waste time reading and parsing the bytestream.
1781 // Note: VM callers should ensure consistency of k/class_name,class_loader
1782 // Be careful when modifying this code: once you have run
1783 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1784 // you need to find_and_remove it before returning.
1785 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1786 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1787 InstanceKlass* k, TRAPS) {
1788
1789 Symbol* name_h = k->name(); // passed in class_name may be null
1790 ClassLoaderData* loader_data = class_loader_data(class_loader);
1791 Dictionary* dictionary = loader_data->dictionary();
1792
1793 unsigned int d_hash = dictionary->compute_hash(name_h);
1794
1795 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1796 unsigned int p_hash = placeholders()->compute_hash(name_h);
1797 int p_index = placeholders()->hash_to_index(p_hash);
1798 PlaceholderEntry* probe;
1799
1800 {
1801 MutexLocker mu(THREAD, SystemDictionary_lock);
1802 // First check if class already defined
1803 if (is_parallelDefine(class_loader)) {
1804 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1805 if (check != NULL) {
1806 return check;
1807 }
1808 }
1809
1810 // Acquire define token for this class/classloader
1811 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1812 // Wait if another thread defining in parallel
1813 // All threads wait - even those that will throw duplicate class: otherwise
1814 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1815 // if other thread has not finished updating dictionary
1816 while (probe->definer() != NULL) {
1817 SystemDictionary_lock->wait();
1818 }
1819 // Only special cases allow parallel defines and can use other thread's results
1820 // Other cases fall through, and may run into duplicate defines
1821 // caught by finding an entry in the SystemDictionary
1822 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1823 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1824 SystemDictionary_lock->notify_all();
1825 #ifdef ASSERT
1826 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1827 assert(check != NULL, "definer missed recording success");
1828 #endif
1829 return probe->instance_klass();
1830 } else {
1831 // This thread will define the class (even if earlier thread tried and had an error)
1832 probe->set_definer(THREAD);
1833 }
1834 }
1835
1836 define_instance_class(k, THREAD);
1837
1838 Handle linkage_exception = Handle(); // null handle
1839
1840 // definer must notify any waiting threads
1841 {
1842 MutexLocker mu(THREAD, SystemDictionary_lock);
1843 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1844 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1845 if (probe != NULL) {
1846 if (HAS_PENDING_EXCEPTION) {
1847 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1848 CLEAR_PENDING_EXCEPTION;
1849 } else {
1850 probe->set_instance_klass(k);
1851 }
1852 probe->set_definer(NULL);
1853 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1854 SystemDictionary_lock->notify_all();
1855 }
1856 }
1857
1858 // Can't throw exception while holding lock due to rank ordering
1859 if (linkage_exception() != NULL) {
1860 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1861 }
1862
1863 return k;
1864 }
1865
1866 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1867 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1868 if (class_loader.is_null()) {
1869 return Handle(THREAD, _system_loader_lock_obj);
1870 } else {
1871 return class_loader;
1872 }
1873 }
1874
1875 // This method is added to check how often we have to wait to grab loader
1876 // lock. The results are being recorded in the performance counters defined in
1877 // ClassLoader::_sync_systemLoaderLockContentionRate and
1878 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1879 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1880 if (!UsePerfData) {
1881 return;
1882 }
1883
1884 assert(!loader_lock.is_null(), "NULL lock object");
1885
1886 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1887 == ObjectSynchronizer::owner_other) {
1888 // contention will likely happen, so increment the corresponding
1889 // contention counter.
1890 if (loader_lock() == _system_loader_lock_obj) {
1891 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1892 } else {
1893 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1894 }
1895 }
1896 }
1897
1898 // ----------------------------------------------------------------------------
1899 // Lookup
1900
1901 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1902 Symbol* class_name,
1903 Dictionary* dictionary) {
1904 assert_locked_or_safepoint(SystemDictionary_lock);
1905 int index = dictionary->hash_to_index(hash);
1906 return dictionary->find_class(index, hash, class_name);
1907 }
1908
1909
1910 // Basic find on classes in the midst of being loaded
1911 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1912 ClassLoaderData* loader_data) {
1913 assert_locked_or_safepoint(SystemDictionary_lock);
1914 unsigned int p_hash = placeholders()->compute_hash(class_name);
1915 int p_index = placeholders()->hash_to_index(p_hash);
1916 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1917 }
1918
1919
1920 // Used for assertions and verification only
1921 // Precalculating the hash and index is an optimization because there are many lookups
1922 // before adding the class.
1923 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1924 assert_locked_or_safepoint(SystemDictionary_lock);
1925 #ifndef ASSERT
1926 guarantee(VerifyBeforeGC ||
1927 VerifyDuringGC ||
1928 VerifyBeforeExit ||
1929 VerifyDuringStartup ||
1930 VerifyAfterGC, "too expensive");
1931 #endif
1932
1933 Dictionary* dictionary = loader_data->dictionary();
1934 unsigned int d_hash = dictionary->compute_hash(class_name);
1935 return find_class(d_hash, class_name, dictionary);
1936 }
1937
1938
1939 // ----------------------------------------------------------------------------
1940 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1941 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1942 // before a new class is used.
1943
1944 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1945 assert(k != NULL, "just checking");
1946 if (Universe::is_fully_initialized()) {
1947 assert_locked_or_safepoint(Compile_lock);
1948 }
1949
1950 k->set_init_state(InstanceKlass::loaded);
1951 // make sure init_state store is already done.
1952 // The compiler reads the hierarchy outside of the Compile_lock.
1953 // Access ordering is used to add to hierarchy.
1954
1955 // Link into hierachy.
1956 k->append_to_sibling_list(); // add to superklass/sibling list
1957 k->process_interfaces(THREAD); // handle all "implements" declarations
1958
1959 // Now flush all code that depended on old class hierarchy.
1960 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1961 if (Universe::is_fully_initialized()) {
1962 CodeCache::flush_dependents_on(k);
1963 }
1964 }
1965
1966 // ----------------------------------------------------------------------------
1967 // GC support
1968
1969 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1970 // Note: anonymous classes are not in the SD.
1971 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1972
1973 bool unloading_occurred;
1974 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1975 {
1976 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1977 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1978 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1979 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1980 if (unloading_occurred) {
1981 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1982 JFR_ONLY(Jfr::on_unloading_classes();)
1983
1984 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1985 ClassLoaderDataGraph::clean_module_and_package_info();
1986 constraints()->purge_loader_constraints();
1987 resolution_errors()->purge_resolution_errors();
1988 }
1989 }
1990
1991 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1992
1993 if (unloading_occurred) {
1994 SymbolTable::trigger_cleanup();
1995
1996 // Oops referenced by the protection domain cache table may get unreachable independently
1997 // of the class loader (eg. cached protection domain oops). So we need to
1998 // explicitly unlink them here.
1999 // All protection domain oops are linked to the caller class, so if nothing
2000 // unloads, this is not needed.
2001 _pd_cache_table->trigger_cleanup();
2002 }
2003
2004 return unloading_occurred;
2005 }
2006
2007 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
2008 f->do_oop(&_java_system_loader);
2009 f->do_oop(&_java_platform_loader);
2010 f->do_oop(&_system_loader_lock_obj);
2011 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
2012
2013 // Visit extra methods
2014 invoke_method_table()->oops_do(f);
2015
2016 if (include_handles) {
2017 OopStorageSet::vm_global()->oops_do(f);
2018 }
2019 }
2020
2021 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
2022 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
2023 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
2024 it->push(well_known_klass_addr((WKID)id));
2025 }
2026 }
2027
2028 void SystemDictionary::methods_do(void f(Method*)) {
2029 // Walk methods in loaded classes
2030 MutexLocker ml(ClassLoaderDataGraph_lock);
2031 ClassLoaderDataGraph::methods_do(f);
2032 // Walk method handle intrinsics
2033 invoke_method_table()->methods_do(f);
2034 }
2035
2036 // ----------------------------------------------------------------------------
2037 // Initialization
2038
2039 void SystemDictionary::initialize(TRAPS) {
2040 // Allocate arrays
2041 _placeholders = new PlaceholderTable(_placeholder_table_size);
2042 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2043 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2044 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2045 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2046
2047 // Allocate private object used as system class loader lock
2048 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2049 // Initialize basic classes
2050 resolve_well_known_classes(CHECK);
2051 }
2052
2053 // Compact table of directions on the initialization of klasses:
2054 static const short wk_init_info[] = {
2055 #define WK_KLASS_INIT_INFO(name, symbol) \
2056 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
2057
2058 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2059 #undef WK_KLASS_INIT_INFO
2060 0
2061 };
2062
2063 #ifdef ASSERT
2064 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
2065 int sid;
2066 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
2067 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2068 if (class_name == symbol) {
2069 return true;
2070 }
2071 }
2072 return false;
2073 }
2074 #endif
2075
2076 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
2077 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2078 int sid = wk_init_info[id - FIRST_WKID];
2079 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2080 InstanceKlass** klassp = &_well_known_klasses[id];
2081
2082 #if INCLUDE_CDS
2083 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
2084 InstanceKlass* k = *klassp;
2085 assert(k->is_shared_boot_class(), "must be");
2086
2087 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
2088 quick_resolve(k, loader_data, Handle(), CHECK_false);
2089 return true;
2090 }
2091 #endif // INCLUDE_CDS
2092
2093 if (!is_wk_klass_loaded(*klassp)) {
2094 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
2095 (*klassp) = InstanceKlass::cast(k);
2096 }
2097 return ((*klassp) != NULL);
2098 }
2099
2100 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2101 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2102 for (int id = (int)start_id; id < (int)limit_id; id++) {
2103 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2104 resolve_wk_klass((WKID)id, CHECK);
2105 }
2106
2107 // move the starting value forward to the limit:
2108 start_id = limit_id;
2109 }
2110
2111 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2112 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
2113
2114 // Create the ModuleEntry for java.base. This call needs to be done here,
2115 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2116 ClassLoader::classLoader_init2(CHECK);
2117
2118 // Preload commonly used klasses
2119 WKID scan = FIRST_WKID;
2120 // first do Object, then String, Class
2121 #if INCLUDE_CDS
2122 if (UseSharedSpaces) {
2123 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2124
2125 // It's unsafe to access the archived heap regions before they
2126 // are fixed up, so we must do the fixup as early as possible
2127 // before the archived java objects are accessed by functions
2128 // such as java_lang_Class::restore_archived_mirror and
2129 // ConstantPool::restore_unshareable_info (restores the archived
2130 // resolved_references array object).
2131 //
2132 // HeapShared::fixup_mapped_heap_regions() fills the empty
2133 // spaces in the archived heap regions and may use
2134 // SystemDictionary::Object_klass(), so we can do this only after
2135 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2136 // call. No mirror objects are accessed/restored in the above call.
2137 // Mirrors are restored after java.lang.Class is loaded.
2138 HeapShared::fixup_mapped_heap_regions();
2139
2140 // Initialize the constant pool for the Object_class
2141 assert(Object_klass()->is_shared(), "must be");
2142 Object_klass()->constants()->restore_unshareable_info(CHECK);
2143 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2144 } else
2145 #endif
2146 {
2147 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2148 }
2149
2150 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2151
2152 java_lang_Object::register_natives(CHECK);
2153
2154 // Calculate offsets for String and Class classes since they are loaded and
2155 // can be used after this point.
2156 java_lang_String::compute_offsets();
2157 java_lang_Class::compute_offsets();
2158
2159 // Fixup mirrors for classes loaded before java.lang.Class.
2160 Universe::initialize_basic_type_mirrors(CHECK);
2161 Universe::fixup_mirrors(CHECK);
2162
2163 // do a bunch more:
2164 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2165
2166 // The offsets for jlr.Reference must be computed before
2167 // InstanceRefKlass::update_nonstatic_oop_maps is called. That function uses
2168 // the offsets to remove the referent and discovered fields from the oop maps,
2169 // as they are treated in a special way by the GC. Removing these oops from the
2170 // oop maps must be done before the usual subclasses of jlr.Reference are loaded.
2171 java_lang_ref_Reference::compute_offsets();
2172
2173 // Preload ref klasses and set reference types
2174 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2175 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2176
2177 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2178 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2179 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2180 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2181 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2182
2183 // JSR 292 classes
2184 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2185 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2186 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2187 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2188 WKID last = WKID_LIMIT;
2189 resolve_wk_klasses_until(last, scan, CHECK);
2190
2191 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2192 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2193 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2194 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2195 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2196 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2197 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2198 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2199 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2200 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2201
2202 #ifdef ASSERT
2203 if (UseSharedSpaces) {
2204 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2205 "All well known classes must be resolved in JVMTI early phase"));
2206 for (int i = FIRST_WKID; i < last; i++) {
2207 InstanceKlass* k = _well_known_klasses[i];
2208 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2209 }
2210 }
2211 #endif
2212 }
2213
2214 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2215 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2216 BasicType SystemDictionary::box_klass_type(Klass* k) {
2217 assert(k != NULL, "");
2218 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2219 if (_box_klasses[i] == k)
2220 return (BasicType)i;
2221 }
2222 return T_OBJECT;
2223 }
2224
2225 // Constraints on class loaders. The details of the algorithm can be
2226 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2227 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2228 // that the dictionary needs to maintain a set of contraints that
2229 // must be satisfied by all classes in the dictionary.
2230 // if defining is true, then LinkageError if already in dictionary
2231 // if initiating loader, then ok if InstanceKlass matches existing entry
2232
2233 void SystemDictionary::check_constraints(unsigned int d_hash,
2234 InstanceKlass* k,
2235 Handle class_loader,
2236 bool defining,
2237 TRAPS) {
2238 ResourceMark rm(THREAD);
2239 stringStream ss;
2240 bool throwException = false;
2241
2242 {
2243 Symbol *name = k->name();
2244 ClassLoaderData *loader_data = class_loader_data(class_loader);
2245
2246 MutexLocker mu(THREAD, SystemDictionary_lock);
2247
2248 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2249 if (check != NULL) {
2250 // If different InstanceKlass - duplicate class definition,
2251 // else - ok, class loaded by a different thread in parallel.
2252 // We should only have found it if it was done loading and ok to use.
2253 // The dictionary only holds instance classes, placeholders
2254 // also hold array classes.
2255
2256 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2257 if ((defining == true) || (k != check)) {
2258 throwException = true;
2259 ss.print("loader %s", loader_data->loader_name_and_id());
2260 ss.print(" attempted duplicate %s definition for %s. (%s)",
2261 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2262 } else {
2263 return;
2264 }
2265 }
2266
2267 #ifdef ASSERT
2268 Symbol* ph_check = find_placeholder(name, loader_data);
2269 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2270 #endif
2271
2272 if (throwException == false) {
2273 if (constraints()->check_or_update(k, class_loader, name) == false) {
2274 throwException = true;
2275 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2276 ss.print(" wants to load %s %s.",
2277 k->external_kind(), k->external_name());
2278 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2279 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2280 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2281 existing_klass->external_kind(),
2282 existing_klass->class_loader_data()->loader_name_and_id(),
2283 existing_klass->class_in_module_of_loader(false, true));
2284 } else {
2285 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2286 }
2287 }
2288 }
2289 }
2290
2291 // Throw error now if needed (cannot throw while holding
2292 // SystemDictionary_lock because of rank ordering)
2293 if (throwException == true) {
2294 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2295 }
2296 }
2297
2298 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2299 // have been called.
2300 void SystemDictionary::update_dictionary(unsigned int d_hash,
2301 int p_index, unsigned int p_hash,
2302 InstanceKlass* k,
2303 Handle class_loader,
2304 TRAPS) {
2305 // Compile_lock prevents systemDictionary updates during compilations
2306 assert_locked_or_safepoint(Compile_lock);
2307 Symbol* name = k->name();
2308 ClassLoaderData *loader_data = class_loader_data(class_loader);
2309
2310 {
2311 MutexLocker mu1(THREAD, SystemDictionary_lock);
2312
2313 // Make a new dictionary entry.
2314 Dictionary* dictionary = loader_data->dictionary();
2315 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2316 if (sd_check == NULL) {
2317 dictionary->add_klass(d_hash, name, k);
2318 }
2319 #ifdef ASSERT
2320 sd_check = find_class(d_hash, name, dictionary);
2321 assert (sd_check != NULL, "should have entry in dictionary");
2322 // Note: there may be a placeholder entry: for circularity testing
2323 // or for parallel defines
2324 #endif
2325 SystemDictionary_lock->notify_all();
2326 }
2327 }
2328
2329
2330 // Try to find a class name using the loader constraints. The
2331 // loader constraints might know about a class that isn't fully loaded
2332 // yet and these will be ignored.
2333 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2334 Symbol* class_name, Handle class_loader, TRAPS) {
2335
2336 // First see if it has been loaded directly.
2337 // Force the protection domain to be null. (This removes protection checks.)
2338 Handle no_protection_domain;
2339 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2340 no_protection_domain, CHECK_NULL);
2341 if (klass != NULL)
2342 return klass;
2343
2344 // Now look to see if it has been loaded elsewhere, and is subject to
2345 // a loader constraint that would require this loader to return the
2346 // klass that is already loaded.
2347 if (Signature::is_array(class_name)) {
2348 // For array classes, their Klass*s are not kept in the
2349 // constraint table. The element Klass*s are.
2350 SignatureStream ss(class_name, false);
2351 int ndims = ss.skip_array_prefix(); // skip all '['s
2352 BasicType t = ss.type();
2353 if (t != T_OBJECT) {
2354 klass = Universe::typeArrayKlassObj(t);
2355 } else {
2356 MutexLocker mu(THREAD, SystemDictionary_lock);
2357 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2358 }
2359 // If element class already loaded, allocate array klass
2360 if (klass != NULL) {
2361 klass = klass->array_klass_or_null(ndims);
2362 }
2363 } else {
2364 MutexLocker mu(THREAD, SystemDictionary_lock);
2365 // Non-array classes are easy: simply check the constraint table.
2366 klass = constraints()->find_constrained_klass(class_name, class_loader);
2367 }
2368
2369 return klass;
2370 }
2371
2372 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2373 Klass* klass_being_linked,
2374 Handle class_loader1,
2375 Handle class_loader2,
2376 Thread* THREAD) {
2377 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2378 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2379
2380 Symbol* constraint_name = NULL;
2381
2382 if (!Signature::is_array(class_name)) {
2383 constraint_name = class_name;
2384 } else {
2385 // For array classes, their Klass*s are not kept in the
2386 // constraint table. The element classes are.
2387 SignatureStream ss(class_name, false);
2388 ss.skip_array_prefix(); // skip all '['s
2389 if (!ss.has_envelope()) {
2390 return true; // primitive types always pass
2391 }
2392 constraint_name = ss.as_symbol();
2393 // Increment refcount to keep constraint_name alive after
2394 // SignatureStream is destructed. It will be decremented below
2395 // before returning.
2396 constraint_name->increment_refcount();
2397 }
2398
2399 Dictionary* dictionary1 = loader_data1->dictionary();
2400 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2401
2402 Dictionary* dictionary2 = loader_data2->dictionary();
2403 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2404
2405 {
2406 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2407 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2408 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2409 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2410 klass2, class_loader2);
2411 #if INCLUDE_CDS
2412 if (Arguments::is_dumping_archive() && klass_being_linked != NULL &&
2413 !klass_being_linked->is_shared()) {
2414 SystemDictionaryShared::record_linking_constraint(constraint_name,
2415 InstanceKlass::cast(klass_being_linked),
2416 class_loader1, class_loader2, THREAD);
2417 }
2418 #endif // INCLUDE_CDS
2419 if (Signature::is_array(class_name)) {
2420 constraint_name->decrement_refcount();
2421 }
2422 return result;
2423 }
2424 }
2425
2426 // Add entry to resolution error table to record the error when the first
2427 // attempt to resolve a reference to a class has failed.
2428 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2429 Symbol* error, Symbol* message) {
2430 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2431 int index = resolution_errors()->hash_to_index(hash);
2432 {
2433 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2434 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2435 }
2436 }
2437
2438 // Delete a resolution error for RedefineClasses for a constant pool is going away
2439 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2440 resolution_errors()->delete_entry(pool);
2441 }
2442
2443 // Lookup resolution error table. Returns error if found, otherwise NULL.
2444 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2445 Symbol** message) {
2446 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2447 int index = resolution_errors()->hash_to_index(hash);
2448 {
2449 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2450 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2451 if (entry != NULL) {
2452 *message = entry->message();
2453 return entry->error();
2454 } else {
2455 return NULL;
2456 }
2457 }
2458 }
2459
2460 // Add an entry to resolution error table to record an error in resolving or
2461 // validating a nest host. This is used to construct informative error
2462 // messages when IllegalAccessError's occur. If an entry already exists it will
2463 // be updated with the nest host error message.
2464 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
2465 int which,
2466 const char* message) {
2467 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2468 int index = resolution_errors()->hash_to_index(hash);
2469 {
2470 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2471 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2472 if (entry != NULL) {
2473 assert(entry->nest_host_error() == NULL, "Nest host error message already set!");
2474 entry->set_nest_host_error(message);
2475 } else {
2476 resolution_errors()->add_entry(index, hash, pool, which, message);
2477 }
2478 }
2479 }
2480
2481 // Lookup any nest host error
2482 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
2483 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2484 int index = resolution_errors()->hash_to_index(hash);
2485 {
2486 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2487 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2488 if (entry != NULL) {
2489 return entry->nest_host_error();
2490 } else {
2491 return NULL;
2492 }
2493 }
2494 }
2495
2496
2497 // Signature constraints ensure that callers and callees agree about
2498 // the meaning of type names in their signatures. This routine is the
2499 // intake for constraints. It collects them from several places:
2500 //
2501 // * LinkResolver::resolve_method (if check_access is true) requires
2502 // that the resolving class (the caller) and the defining class of
2503 // the resolved method (the callee) agree on each type in the
2504 // method's signature.
2505 //
2506 // * LinkResolver::resolve_interface_method performs exactly the same
2507 // checks.
2508 //
2509 // * LinkResolver::resolve_field requires that the constant pool
2510 // attempting to link to a field agree with the field's defining
2511 // class about the type of the field signature.
2512 //
2513 // * klassVtable::initialize_vtable requires that, when a class
2514 // overrides a vtable entry allocated by a superclass, that the
2515 // overriding method (i.e., the callee) agree with the superclass
2516 // on each type in the method's signature.
2517 //
2518 // * klassItable::initialize_itable requires that, when a class fills
2519 // in its itables, for each non-abstract method installed in an
2520 // itable, the method (i.e., the callee) agree with the interface
2521 // on each type in the method's signature.
2522 //
2523 // All those methods have a boolean (check_access, checkconstraints)
2524 // which turns off the checks. This is used from specialized contexts
2525 // such as bootstrapping, dumping, and debugging.
2526 //
2527 // No direct constraint is placed between the class and its
2528 // supertypes. Constraints are only placed along linked relations
2529 // between callers and callees. When a method overrides or implements
2530 // an abstract method in a supertype (superclass or interface), the
2531 // constraints are placed as if the supertype were the caller to the
2532 // overriding method. (This works well, since callers to the
2533 // supertype have already established agreement between themselves and
2534 // the supertype.) As a result of all this, a class can disagree with
2535 // its supertype about the meaning of a type name, as long as that
2536 // class neither calls a relevant method of the supertype, nor is
2537 // called (perhaps via an override) from the supertype.
2538 //
2539 //
2540 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
2541 //
2542 // Make sure all class components (including arrays) in the given
2543 // signature will be resolved to the same class in both loaders.
2544 // Returns the name of the type that failed a loader constraint check, or
2545 // NULL if no constraint failed. No exception except OOME is thrown.
2546 // Arrays are not added to the loader constraint table, their elements are.
2547 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2548 Klass* klass_being_linked,
2549 Handle loader1, Handle loader2,
2550 bool is_method, TRAPS) {
2551 // Nothing to do if loaders are the same.
2552 if (loader1() == loader2()) {
2553 return NULL;
2554 }
2555
2556 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2557 if (ss.is_reference()) {
2558 Symbol* sig = ss.as_symbol();
2559 // Note: In the future, if template-like types can take
2560 // arguments, we will want to recognize them and dig out class
2561 // names hiding inside the argument lists.
2562 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2, THREAD)) {
2563 return sig;
2564 }
2565 }
2566 }
2567 return NULL;
2568 }
2569
2570 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2571 Symbol* signature,
2572 TRAPS) {
2573 methodHandle empty;
2574 assert(MethodHandles::is_signature_polymorphic(iid) &&
2575 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2576 iid != vmIntrinsics::_invokeGeneric,
2577 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2578
2579 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2580 int index = invoke_method_table()->hash_to_index(hash);
2581 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2582 methodHandle m;
2583 if (spe == NULL || spe->method() == NULL) {
2584 spe = NULL;
2585 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2586 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2587 if (!Arguments::is_interpreter_only()) {
2588 // Generate a compiled form of the MH intrinsic.
2589 AdapterHandlerLibrary::create_native_wrapper(m);
2590 // Check if have the compiled code.
2591 if (!m->has_compiled_code()) {
2592 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2593 "Out of space in CodeCache for method handle intrinsic");
2594 }
2595 }
2596 // Now grab the lock. We might have to throw away the new method,
2597 // if a racing thread has managed to install one at the same time.
2598 {
2599 MutexLocker ml(THREAD, SystemDictionary_lock);
2600 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2601 if (spe == NULL)
2602 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2603 if (spe->method() == NULL)
2604 spe->set_method(m());
2605 }
2606 }
2607
2608 assert(spe != NULL && spe->method() != NULL, "");
2609 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2610 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2611 "MH intrinsic invariant");
2612 return spe->method();
2613 }
2614
2615 // Helper for unpacking the return value from linkMethod and linkCallSite.
2616 static Method* unpack_method_and_appendix(Handle mname,
2617 Klass* accessing_klass,
2618 objArrayHandle appendix_box,
2619 Handle* appendix_result,
2620 TRAPS) {
2621 if (mname.not_null()) {
2622 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2623 if (m != NULL) {
2624 oop appendix = appendix_box->obj_at(0);
2625 LogTarget(Info, methodhandles) lt;
2626 if (lt.develop_is_enabled()) {
2627 ResourceMark rm(THREAD);
2628 LogStream ls(lt);
2629 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2630 m->print_on(&ls);
2631 if (appendix != NULL) { ls.print("appendix = "); appendix->print_on(&ls); }
2632 ls.cr();
2633 }
2634
2635 (*appendix_result) = Handle(THREAD, appendix);
2636 // the target is stored in the cpCache and if a reference to this
2637 // MemberName is dropped we need a way to make sure the
2638 // class_loader containing this method is kept alive.
2639 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2640 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2641 this_key->record_dependency(m->method_holder());
2642 return mh();
2643 }
2644 }
2645 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2646 }
2647
2648 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2649 Symbol* name,
2650 Symbol* signature,
2651 Klass* accessing_klass,
2652 Handle *appendix_result,
2653 TRAPS) {
2654 assert(THREAD->can_call_java() ,"");
2655 Handle method_type =
2656 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2657
2658 int ref_kind = JVM_REF_invokeVirtual;
2659 oop name_oop = StringTable::intern(name, CHECK_NULL);
2660 Handle name_str (THREAD, name_oop);
2661 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2662 assert(appendix_box->obj_at(0) == NULL, "");
2663
2664 // This should not happen. JDK code should take care of that.
2665 if (accessing_klass == NULL || method_type.is_null()) {
2666 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2667 }
2668
2669 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2670 JavaCallArguments args;
2671 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2672 args.push_int(ref_kind);
2673 args.push_oop(Handle(THREAD, klass->java_mirror()));
2674 args.push_oop(name_str);
2675 args.push_oop(method_type);
2676 args.push_oop(appendix_box);
2677 JavaValue result(T_OBJECT);
2678 JavaCalls::call_static(&result,
2679 SystemDictionary::MethodHandleNatives_klass(),
2680 vmSymbols::linkMethod_name(),
2681 vmSymbols::linkMethod_signature(),
2682 &args, CHECK_NULL);
2683 Handle mname(THREAD, (oop) result.get_jobject());
2684 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2685 }
2686
2687 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2688 // We must ensure that all class loaders everywhere will reach this class, for any client.
2689 // This is a safe bet for public classes in java.lang, such as Object and String.
2690 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2691 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2692 static bool is_always_visible_class(oop mirror) {
2693 Klass* klass = java_lang_Class::as_Klass(mirror);
2694 if (klass->is_objArray_klass()) {
2695 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2696 }
2697 if (klass->is_typeArray_klass()) {
2698 return true; // primitive array
2699 }
2700 assert(klass->is_instance_klass(), "%s", klass->external_name());
2701 return klass->is_public() &&
2702 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2703 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2704 }
2705
2706 // Find or construct the Java mirror (java.lang.Class instance) for
2707 // the given field type signature, as interpreted relative to the
2708 // given class loader. Handles primitives, void, references, arrays,
2709 // and all other reflectable types, except method types.
2710 // N.B. Code in reflection should use this entry point.
2711 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2712 Klass* accessing_klass,
2713 Handle class_loader,
2714 Handle protection_domain,
2715 SignatureStream::FailureMode failure_mode,
2716 TRAPS) {
2717 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2718 "one or the other, or perhaps neither");
2719
2720 // What we have here must be a valid field descriptor,
2721 // and all valid field descriptors are supported.
2722 // Produce the same java.lang.Class that reflection reports.
2723 if (accessing_klass != NULL) {
2724 class_loader = Handle(THREAD, accessing_klass->class_loader());
2725 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2726 }
2727 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2728 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2729 if (mirror_oop == NULL) {
2730 return Handle(); // report failure this way
2731 }
2732 Handle mirror(THREAD, mirror_oop);
2733
2734 if (accessing_klass != NULL) {
2735 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2736 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2737 if (sel_klass != NULL) {
2738 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2739 }
2740 }
2741 return mirror;
2742 }
2743
2744
2745 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2746 // signature, as interpreted relative to the given class loader.
2747 // Because of class loader constraints, all method handle usage must be
2748 // consistent with this loader.
2749 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2750 Klass* accessing_klass,
2751 TRAPS) {
2752 Handle empty;
2753 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2754 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2755 int index = invoke_method_table()->hash_to_index(hash);
2756 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2757 if (spe != NULL && spe->method_type() != NULL) {
2758 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2759 return Handle(THREAD, spe->method_type());
2760 } else if (!THREAD->can_call_java()) {
2761 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2762 return Handle(); // do not attempt from within compiler, unless it was cached
2763 }
2764
2765 Handle class_loader, protection_domain;
2766 if (accessing_klass != NULL) {
2767 class_loader = Handle(THREAD, accessing_klass->class_loader());
2768 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2769 }
2770 bool can_be_cached = true;
2771 int npts = ArgumentCount(signature).size();
2772 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2773 int arg = 0;
2774 Handle rt; // the return type from the signature
2775 ResourceMark rm(THREAD);
2776 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2777 oop mirror = NULL;
2778 if (can_be_cached) {
2779 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2780 mirror = ss.as_java_mirror(Handle(), Handle(),
2781 SignatureStream::ReturnNull, CHECK_(empty));
2782 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2783 // Fall back to accessing_klass context.
2784 can_be_cached = false;
2785 }
2786 }
2787 if (!can_be_cached) {
2788 // Resolve, throwing a real error if it doesn't work.
2789 mirror = ss.as_java_mirror(class_loader, protection_domain,
2790 SignatureStream::NCDFError, CHECK_(empty));
2791 }
2792 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2793 if (ss.at_return_type())
2794 rt = Handle(THREAD, mirror);
2795 else
2796 pts->obj_at_put(arg++, mirror);
2797
2798 // Check accessibility.
2799 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2800 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2801 mirror = NULL; // safety
2802 // Emulate ConstantPool::verify_constant_pool_resolve.
2803 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2804 }
2805 }
2806 assert(arg == npts, "");
2807
2808 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2809 JavaCallArguments args(Handle(THREAD, rt()));
2810 args.push_oop(pts);
2811 JavaValue result(T_OBJECT);
2812 JavaCalls::call_static(&result,
2813 SystemDictionary::MethodHandleNatives_klass(),
2814 vmSymbols::findMethodHandleType_name(),
2815 vmSymbols::findMethodHandleType_signature(),
2816 &args, CHECK_(empty));
2817 Handle method_type(THREAD, (oop) result.get_jobject());
2818
2819 if (can_be_cached) {
2820 // We can cache this MethodType inside the JVM.
2821 MutexLocker ml(THREAD, SystemDictionary_lock);
2822 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2823 if (spe == NULL)
2824 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2825 if (spe->method_type() == NULL) {
2826 spe->set_method_type(method_type());
2827 }
2828 }
2829
2830 // report back to the caller with the MethodType
2831 return method_type;
2832 }
2833
2834 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2835 Klass* accessing_klass,
2836 TRAPS) {
2837 Handle empty;
2838 ResourceMark rm(THREAD);
2839 SignatureStream ss(signature, /*is_method=*/ false);
2840 if (!ss.is_done()) {
2841 Handle class_loader, protection_domain;
2842 if (accessing_klass != NULL) {
2843 class_loader = Handle(THREAD, accessing_klass->class_loader());
2844 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2845 }
2846 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2847 ss.next();
2848 if (ss.is_done()) {
2849 return Handle(THREAD, mirror);
2850 }
2851 }
2852 return empty;
2853 }
2854
2855 // Ask Java code to find or construct a method handle constant.
2856 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2857 int ref_kind, //e.g., JVM_REF_invokeVirtual
2858 Klass* callee,
2859 Symbol* name,
2860 Symbol* signature,
2861 TRAPS) {
2862 Handle empty;
2863 if (caller == NULL) {
2864 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2865 }
2866 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2867 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2868
2869 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2870 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2871 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2872 java_lang_invoke_MemberName::set_name (mname(), name_str());
2873 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2874 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2875
2876 if (ref_kind == JVM_REF_invokeVirtual &&
2877 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2878 // Skip resolution for public signature polymorphic methods such as
2879 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2880 // They require appendix argument which MemberName resolution doesn't handle.
2881 // There's special logic on JDK side to handle them
2882 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2883 } else {
2884 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2885 }
2886
2887 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2888 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2889
2890 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2891 JavaCallArguments args;
2892 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2893 args.push_int(ref_kind);
2894 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2895 args.push_oop(name_str);
2896 args.push_oop(type);
2897 JavaValue result(T_OBJECT);
2898 JavaCalls::call_static(&result,
2899 SystemDictionary::MethodHandleNatives_klass(),
2900 vmSymbols::linkMethodHandleConstant_name(),
2901 vmSymbols::linkMethodHandleConstant_signature(),
2902 &args, CHECK_(empty));
2903 return Handle(THREAD, (oop) result.get_jobject());
2904 }
2905
2906 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2907 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2908 // with linkage results being stored back into the bootstrap specifier.
2909 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2910 // Resolve the bootstrap specifier, its name, type, and static arguments
2911 bootstrap_specifier.resolve_bsm(CHECK);
2912
2913 // This should not happen. JDK code should take care of that.
2914 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2915 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2916 }
2917
2918 bool is_indy = bootstrap_specifier.is_method_call();
2919 objArrayHandle appendix_box;
2920 if (is_indy) {
2921 // Some method calls may require an appendix argument. Arrange to receive it.
2922 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2923 assert(appendix_box->obj_at(0) == NULL, "");
2924 }
2925
2926 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2927 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2928 JavaCallArguments args;
2929 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2930 args.push_int(bootstrap_specifier.bss_index());
2931 args.push_oop(bootstrap_specifier.bsm());
2932 args.push_oop(bootstrap_specifier.name_arg());
2933 args.push_oop(bootstrap_specifier.type_arg());
2934 args.push_oop(bootstrap_specifier.arg_values());
2935 if (is_indy) {
2936 args.push_oop(appendix_box);
2937 }
2938 JavaValue result(T_OBJECT);
2939 JavaCalls::call_static(&result,
2940 SystemDictionary::MethodHandleNatives_klass(),
2941 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2942 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2943 &args, CHECK);
2944
2945 Handle value(THREAD, (oop) result.get_jobject());
2946 if (is_indy) {
2947 Handle appendix;
2948 Method* method = unpack_method_and_appendix(value,
2949 bootstrap_specifier.caller(),
2950 appendix_box,
2951 &appendix, CHECK);
2952 methodHandle mh(THREAD, method);
2953 bootstrap_specifier.set_resolved_method(mh, appendix);
2954 } else {
2955 bootstrap_specifier.set_resolved_value(value);
2956 }
2957
2958 // sanity check
2959 assert(bootstrap_specifier.is_resolved() ||
2960 (bootstrap_specifier.is_method_call() &&
2961 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2962 }
2963
2964 // Protection domain cache table handling
2965
2966 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2967 return _pd_cache_table->get(protection_domain);
2968 }
2969
2970 // ----------------------------------------------------------------------------
2971
2972 void SystemDictionary::print_on(outputStream *st) {
2973 CDS_ONLY(SystemDictionaryShared::print_on(st));
2974 GCMutexLocker mu(SystemDictionary_lock);
2975
2976 ClassLoaderDataGraph::print_dictionary(st);
2977
2978 // Placeholders
2979 placeholders()->print_on(st);
2980 st->cr();
2981
2982 // loader constraints - print under SD_lock
2983 constraints()->print_on(st);
2984 st->cr();
2985
2986 _pd_cache_table->print_on(st);
2987 st->cr();
2988 }
2989
2990 void SystemDictionary::print() { print_on(tty); }
2991
2992 void SystemDictionary::verify() {
2993 guarantee(constraints() != NULL,
2994 "Verify of loader constraints failed");
2995 guarantee(placeholders()->number_of_entries() >= 0,
2996 "Verify of placeholders failed");
2997
2998 GCMutexLocker mu(SystemDictionary_lock);
2999
3000 // Verify dictionary
3001 ClassLoaderDataGraph::verify_dictionary();
3002
3003 placeholders()->verify();
3004
3005 // Verify constraint table
3006 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3007 constraints()->verify(placeholders());
3008
3009 _pd_cache_table->verify();
3010 }
3011
3012 void SystemDictionary::dump(outputStream *st, bool verbose) {
3013 assert_locked_or_safepoint(SystemDictionary_lock);
3014 if (verbose) {
3015 print_on(st);
3016 } else {
3017 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
3018 ClassLoaderDataGraph::print_table_statistics(st);
3019 placeholders()->print_table_statistics(st, "Placeholder Table");
3020 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3021 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
3022 }
3023 }
3024
3025 TableStatistics SystemDictionary::placeholders_statistics() {
3026 MutexLocker ml(SystemDictionary_lock);
3027 return placeholders()->statistics_calculate();
3028 }
3029
3030 TableStatistics SystemDictionary::loader_constraints_statistics() {
3031 MutexLocker ml(SystemDictionary_lock);
3032 return constraints()->statistics_calculate();
3033 }
3034
3035 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
3036 MutexLocker ml(SystemDictionary_lock);
3037 return pd_cache_table()->statistics_calculate();
3038 }
3039
3040 // Utility for dumping dictionaries.
3041 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3042 DCmdWithParser(output, heap),
3043 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3044 "BOOLEAN", false, "false") {
3045 _dcmdparser.add_dcmd_option(&_verbose);
3046 }
3047
3048 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3049 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3050 _verbose.value());
3051 VMThread::execute(&dumper);
3052 }
3053
3054 int SystemDictionaryDCmd::num_arguments() {
3055 ResourceMark rm;
3056 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3057 if (dcmd != NULL) {
3058 DCmdMark mark(dcmd);
3059 return dcmd->_dcmdparser.num_arguments();
3060 } else {
3061 return 0;
3062 }
3063 }