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 "interpreter/bytecodeStream.hpp"
50 #include "interpreter/interpreter.hpp"
51 #include "jfr/jfrEvents.hpp"
52 #include "logging/log.hpp"
53 #include "logging/logStream.hpp"
54 #include "memory/filemap.hpp"
55 #include "memory/heapShared.hpp"
56 #include "memory/metaspaceClosure.hpp"
57 #include "memory/oopFactory.hpp"
58 #include "memory/resourceArea.hpp"
59 #include "memory/universe.hpp"
60 #include "oops/access.inline.hpp"
61 #include "oops/instanceKlass.hpp"
62 #include "oops/instanceRefKlass.hpp"
63 #include "oops/klass.inline.hpp"
64 #include "oops/method.inline.hpp"
65 #include "oops/methodData.hpp"
66 #include "oops/objArrayKlass.hpp"
67 #include "oops/objArrayOop.inline.hpp"
68 #include "oops/oop.inline.hpp"
69 #include "oops/oopHandle.inline.hpp"
70 #include "oops/symbol.hpp"
71 #include "oops/typeArrayKlass.hpp"
72 #include "prims/jvmtiExport.hpp"
73 #include "prims/methodHandles.hpp"
74 #include "runtime/arguments.hpp"
75 #include "runtime/biasedLocking.hpp"
76 #include "runtime/handles.inline.hpp"
77 #include "runtime/java.hpp"
78 #include "runtime/javaCalls.hpp"
79 #include "runtime/mutexLocker.hpp"
80 #include "runtime/sharedRuntime.hpp"
81 #include "runtime/signature.hpp"
82 #include "services/classLoadingService.hpp"
83 #include "services/diagnosticCommand.hpp"
84 #include "services/threadService.hpp"
85 #include "utilities/macros.hpp"
86 #include "utilities/utf8.hpp"
87 #if INCLUDE_CDS
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JFR
91 #include "jfr/jfr.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
101 = { NULL /*, NULL...*/ };
102
103 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
104
105
106 OopHandle SystemDictionary::_system_loader_lock_obj;
107 OopHandle SystemDictionary::_java_system_loader;
108 OopHandle SystemDictionary::_java_platform_loader;
109
110 // Default ProtectionDomainCacheSize value
111
112 const int defaultProtectionDomainCacheSize = 1009;
113
114 ClassLoadInfo::ClassLoadInfo() {
115 _protection_domain = Handle();
116 _unsafe_anonymous_host = NULL;
117 _cp_patches = NULL;
118 _class_hidden_info._dynamic_nest_host = NULL;
119 _class_hidden_info._class_data = Handle();
120 _is_hidden = false;
121 _is_strong_hidden = false;
122 _can_access_vm_annotations = false;
123 }
124
125 ClassLoadInfo::ClassLoadInfo(Handle protection_domain) {
126 _protection_domain = protection_domain;
127 _unsafe_anonymous_host = NULL;
128 _cp_patches = NULL;
129 _class_hidden_info._dynamic_nest_host = NULL;
130 _class_hidden_info._class_data = Handle();
131 _is_hidden = false;
132 _is_strong_hidden = false;
133 _can_access_vm_annotations = false;
134 }
135
136 ClassLoadInfo::ClassLoadInfo(Handle protection_domain,
137 const InstanceKlass* unsafe_anonymous_host,
138 GrowableArray<Handle>* cp_patches,
139 InstanceKlass* dynamic_nest_host,
140 Handle class_data,
141 bool is_hidden,
142 bool is_strong_hidden,
143 bool can_access_vm_annotations) {
144 _protection_domain = protection_domain;
145 _unsafe_anonymous_host = unsafe_anonymous_host;
146 _cp_patches = cp_patches;
147 _class_hidden_info._dynamic_nest_host = dynamic_nest_host;
148 _class_hidden_info._class_data = class_data;
149 _is_hidden = is_hidden;
150 _is_strong_hidden = is_strong_hidden;
151 _can_access_vm_annotations = can_access_vm_annotations;
152 }
153
154 // ----------------------------------------------------------------------------
155 // Java-level SystemLoader and PlatformLoader
156
157 oop SystemDictionary::system_loader_lock() {
158 return _system_loader_lock_obj.resolve();
159 }
160
161 oop SystemDictionary::java_system_loader() {
162 return _java_system_loader.resolve();
163 }
164
165 oop SystemDictionary::java_platform_loader() {
166 return _java_platform_loader.resolve();
167 }
168
169 void SystemDictionary::compute_java_loaders(TRAPS) {
170 JavaValue result(T_OBJECT);
171 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
172 JavaCalls::call_static(&result,
173 class_loader_klass,
174 vmSymbols::getSystemClassLoader_name(),
175 vmSymbols::void_classloader_signature(),
176 CHECK);
177
178 _java_system_loader = OopHandle::create((oop)result.get_jobject());
179
180 JavaCalls::call_static(&result,
181 class_loader_klass,
182 vmSymbols::getPlatformClassLoader_name(),
183 vmSymbols::void_classloader_signature(),
184 CHECK);
185
186 _java_platform_loader = OopHandle::create((oop)result.get_jobject());
187 }
188
189 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
190 if (create_mirror_cld) {
191 // Add a new class loader data to the graph.
192 return ClassLoaderDataGraph::add(class_loader, true);
193 } else {
194 return (class_loader() == NULL) ? ClassLoaderData::the_null_class_loader_data() :
195 ClassLoaderDataGraph::find_or_create(class_loader);
196 }
197 }
198
199 // ----------------------------------------------------------------------------
200 // Parallel class loading check
201
202 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
203 if (class_loader.is_null()) return true;
204 if (AlwaysLockClassLoader) return false;
205 return java_lang_ClassLoader::parallelCapable(class_loader());
206 }
207 // ----------------------------------------------------------------------------
208 // ParallelDefineClass flag does not apply to bootclass loader
209 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
210 if (class_loader.is_null()) return false;
211 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
212 return true;
213 }
214 return false;
215 }
216
217 // Returns true if the passed class loader is the builtin application class loader
218 // or a custom system class loader. A customer system class loader can be
219 // specified via -Djava.system.class.loader.
220 bool SystemDictionary::is_system_class_loader(oop class_loader) {
221 if (class_loader == NULL) {
222 return false;
223 }
224 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
225 class_loader == _java_system_loader.peek());
226 }
227
228 // Returns true if the passed class loader is the platform class loader.
229 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
230 if (class_loader == NULL) {
231 return false;
232 }
233 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
234 }
235
236 // ----------------------------------------------------------------------------
237 // Resolving of classes
238
239 Symbol* SystemDictionary::class_name_symbol(const char* name, Symbol* exception, TRAPS) {
240 if (name == NULL) {
241 THROW_MSG_0(exception, "No class name given");
242 }
243 if ((int)strlen(name) > Symbol::max_length()) {
244 // It's impossible to create this class; the name cannot fit
245 // into the constant pool.
246 Exceptions::fthrow(THREAD_AND_LOCATION, exception,
247 "Class name exceeds maximum length of %d: %s",
248 Symbol::max_length(),
249 name);
250 return NULL;
251 }
252 // Callers should ensure that the name is never an illegal UTF8 string.
253 assert(UTF8::is_legal_utf8((const unsigned char*)name, (int)strlen(name), false),
254 "Class name is not a valid utf8 string.");
255
256 // Make a new symbol for the class name.
257 return SymbolTable::new_symbol(name);
258 }
259
260 // Forwards to resolve_or_null
261
262 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
263 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
264 if (HAS_PENDING_EXCEPTION || klass == NULL) {
265 // can return a null klass
266 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
267 }
268 return klass;
269 }
270
271 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
272 bool throw_error,
273 Klass* klass, TRAPS) {
274 if (HAS_PENDING_EXCEPTION) {
275 // If we have a pending exception we forward it to the caller, unless throw_error is true,
276 // in which case we have to check whether the pending exception is a ClassNotFoundException,
277 // and if so convert it to a NoClassDefFoundError
278 // And chain the original ClassNotFoundException
279 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
280 ResourceMark rm(THREAD);
281 assert(klass == NULL, "Should not have result with exception pending");
282 Handle e(THREAD, PENDING_EXCEPTION);
283 CLEAR_PENDING_EXCEPTION;
284 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
285 } else {
286 return NULL;
287 }
288 }
289 // Class not found, throw appropriate error or exception depending on value of throw_error
290 if (klass == NULL) {
291 ResourceMark rm(THREAD);
292 if (throw_error) {
293 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
294 } else {
295 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
296 }
297 }
298 return klass;
299 }
300
301
302 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
303 bool throw_error, TRAPS)
304 {
305 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
306 }
307
308
309 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
310
311 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
312 if (Signature::is_array(class_name)) {
313 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
314 } else {
315 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
316 }
317 }
318
319 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
320 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
321 Handle class_loader,
322 Handle protection_domain,
323 TRAPS) {
324 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
325 if (Signature::has_envelope(class_name)) {
326 ResourceMark rm(THREAD);
327 // Ignore wrapping L and ;.
328 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
329 class_name->utf8_length() - 2);
330 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
331 } else {
332 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
333 }
334 }
335
336 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
337 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
338 }
339
340 // Forwards to resolve_instance_class_or_null
341
342 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
343 Handle class_loader,
344 Handle protection_domain,
345 TRAPS) {
346 assert(Signature::is_array(class_name), "must be array");
347 ResourceMark rm(THREAD);
348 SignatureStream ss(class_name, false);
349 int ndims = ss.skip_array_prefix(); // skip all '['s
350 Klass* k = NULL;
351 BasicType t = ss.type();
352 if (ss.has_envelope()) {
353 Symbol* obj_class = ss.as_symbol();
354 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
355 class_loader,
356 protection_domain,
357 CHECK_NULL);
358 if (k != NULL) {
359 k = k->array_klass(ndims, CHECK_NULL);
360 }
361 } else {
362 k = Universe::typeArrayKlassObj(t);
363 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
364 }
365 return k;
366 }
367
368
369 // Must be called for any super-class or super-interface resolution
370 // during class definition to allow class circularity checking
371 // super-interface callers:
372 // parse_interfaces - for defineClass & jvmtiRedefineClasses
373 // super-class callers:
374 // ClassFileParser - for defineClass & jvmtiRedefineClasses
375 // load_shared_class - while loading a class from shared archive
376 // resolve_instance_class_or_null:
377 // via: handle_parallel_super_load
378 // when resolving a class that has an existing placeholder with
379 // a saved superclass [i.e. a defineClass is currently in progress]
380 // if another thread is trying to resolve the class, it must do
381 // super-class checks on its own thread to catch class circularity
382 // This last call is critical in class circularity checking for cases
383 // where classloading is delegated to different threads and the
384 // classloader lock is released.
385 // Take the case: Base->Super->Base
386 // 1. If thread T1 tries to do a defineClass of class Base
387 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
388 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
389 // so it tries to load Super
390 // 3. If we load the class internally, or user classloader uses same thread
391 // loadClassFromxxx or defineClass via parseClassFile Super ...
392 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
393 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
394 // 3.4 calls resolve_super_or_fail Base
395 // 3.5 finds T1,Base -> throws class circularity
396 //OR 4. If T2 tries to resolve Super via defineClass Super ...
397 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
398 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
399 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
400 // 4.4 finds T2, Super -> throws class circularity
401 // Must be called, even if superclass is null, since this is
402 // where the placeholder entry is created which claims this
403 // thread is loading this class/classloader.
404 // Be careful when modifying this code: once you have run
405 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
406 // you need to find_and_remove it before returning.
407 // So be careful to not exit with a CHECK_ macro betweeen these calls.
408 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
409 Symbol* super_name,
410 Handle class_loader,
411 Handle protection_domain,
412 bool is_superclass,
413 TRAPS) {
414 assert(!Signature::is_array(super_name), "invalid super class name");
415 #if INCLUDE_CDS
416 if (DumpSharedSpaces) {
417 // Special processing for handling UNREGISTERED shared classes.
418 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
419 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
420 if (k) {
421 return k;
422 }
423 }
424 #endif // INCLUDE_CDS
425
426 // Double-check, if child class is already loaded, just return super-class,interface
427 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
428 // dictionary.
429 // Make sure there's a placeholder for the *child* before resolving.
430 // Used as a claim that this thread is currently loading superclass/classloader
431 // Used here for ClassCircularity checks and also for heap verification
432 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
433 // Must check ClassCircularity before checking if super class is already loaded.
434 //
435 // We might not already have a placeholder if this child_name was
436 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
437 // the name of the class might not be known until the stream is actually
438 // parsed.
439 // Bugs 4643874, 4715493
440
441 ClassLoaderData* loader_data = class_loader_data(class_loader);
442 Dictionary* dictionary = loader_data->dictionary();
443 unsigned int d_hash = dictionary->compute_hash(child_name);
444 unsigned int p_hash = placeholders()->compute_hash(child_name);
445 int p_index = placeholders()->hash_to_index(p_hash);
446 // can't throw error holding a lock
447 bool child_already_loaded = false;
448 bool throw_circularity_error = false;
449 {
450 MutexLocker mu(THREAD, SystemDictionary_lock);
451 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
452 InstanceKlass* quicksuperk;
453 // to support // loading: if child done loading, just return superclass
454 // if super_name, & class_loader don't match:
455 // if initial define, SD update will give LinkageError
456 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
457 // so we don't throw an exception here.
458 // see: nsk redefclass014 & java.lang.instrument Instrument032
459 if ((childk != NULL ) && (is_superclass) &&
460 ((quicksuperk = childk->java_super()) != NULL) &&
461 ((quicksuperk->name() == super_name) &&
462 (quicksuperk->class_loader() == class_loader()))) {
463 return quicksuperk;
464 } else {
465 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
466 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
467 throw_circularity_error = true;
468 }
469 }
470 if (!throw_circularity_error) {
471 // Be careful not to exit resolve_super
472 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
473 }
474 }
475 if (throw_circularity_error) {
476 ResourceMark rm(THREAD);
477 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
478 }
479
480 // java.lang.Object should have been found above
481 assert(super_name != NULL, "null super class for resolving");
482 // Resolve the super class or interface, check results on return
483 InstanceKlass* superk =
484 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
485 class_loader,
486 protection_domain,
487 THREAD);
488
489 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
490 // It is no longer necessary to keep the placeholder table alive until update_dictionary
491 // or error. GC used to walk the placeholder table as strong roots.
492 // The instanceKlass is kept alive because the class loader is on the stack,
493 // which keeps the loader_data alive, as well as all instanceKlasses in
494 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
495 {
496 MutexLocker mu(THREAD, SystemDictionary_lock);
497 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
498 SystemDictionary_lock->notify_all();
499 }
500 if (HAS_PENDING_EXCEPTION || superk == NULL) {
501 // can null superk
502 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
503 assert(k == NULL || k == superk, "must be");
504 if (k == NULL) {
505 superk = NULL;
506 }
507 }
508
509 return superk;
510 }
511
512 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
513 Handle class_loader,
514 Handle protection_domain,
515 TRAPS) {
516 // Now we have to call back to java to check if the initating class has access
517 JavaValue result(T_VOID);
518 LogTarget(Debug, protectiondomain) lt;
519 if (lt.is_enabled()) {
520 ResourceMark rm(THREAD);
521 // Print out trace information
522 LogStream ls(lt);
523 ls.print_cr("Checking package access");
524 if (class_loader() != NULL) {
525 ls.print("class loader: ");
526 class_loader()->print_value_on(&ls);
527 } else {
528 ls.print_cr("class loader: NULL");
529 }
530 if (protection_domain() != NULL) {
531 ls.print(" protection domain: ");
532 protection_domain()->print_value_on(&ls);
533 } else {
534 ls.print_cr(" protection domain: NULL");
535 }
536 ls.print(" loading: "); klass->print_value_on(&ls);
537 ls.cr();
538 }
539
540 // This handle and the class_loader handle passed in keeps this class from
541 // being unloaded through several GC points.
542 // The class_loader handle passed in is the initiating loader.
543 Handle mirror(THREAD, klass->java_mirror());
544
545 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
546 JavaCalls::call_special(&result,
547 class_loader,
548 system_loader,
549 vmSymbols::checkPackageAccess_name(),
550 vmSymbols::class_protectiondomain_signature(),
551 mirror,
552 protection_domain,
553 THREAD);
554
555 if (HAS_PENDING_EXCEPTION) {
556 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
557 } else {
558 log_debug(protectiondomain)("granted");
559 }
560
561 if (HAS_PENDING_EXCEPTION) return;
562
563 // If no exception has been thrown, we have validated the protection domain
564 // Insert the protection domain of the initiating class into the set.
565 {
566 ClassLoaderData* loader_data = class_loader_data(class_loader);
567 Dictionary* dictionary = loader_data->dictionary();
568
569 Symbol* kn = klass->name();
570 unsigned int d_hash = dictionary->compute_hash(kn);
571
572 MutexLocker mu(THREAD, SystemDictionary_lock);
573 int d_index = dictionary->hash_to_index(d_hash);
574 dictionary->add_protection_domain(d_index, d_hash, klass,
575 protection_domain, THREAD);
576 }
577 }
578
579 // We only get here if this thread finds that another thread
580 // has already claimed the placeholder token for the current operation,
581 // but that other thread either never owned or gave up the
582 // object lock
583 // Waits on SystemDictionary_lock to indicate placeholder table updated
584 // On return, caller must recheck placeholder table state
585 //
586 // We only get here if
587 // 1) custom classLoader, i.e. not bootstrap classloader
588 // 2) custom classLoader has broken the class loader objectLock
589 // so another thread got here in parallel
590 //
591 // lockObject must be held.
592 // Complicated dance due to lock ordering:
593 // Must first release the classloader object lock to
594 // allow initial definer to complete the class definition
595 // and to avoid deadlock
596 // Reclaim classloader lock object with same original recursion count
597 // Must release SystemDictionary_lock after notify, since
598 // class loader lock must be claimed before SystemDictionary_lock
599 // to prevent deadlocks
600 //
601 // The notify allows applications that did an untimed wait() on
602 // the classloader object lock to not hang.
603 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
604 assert_lock_strong(SystemDictionary_lock);
605
606 bool calledholdinglock
607 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
608 assert(calledholdinglock,"must hold lock for notify");
609 assert((lockObject() != _system_loader_lock_obj.resolve() &&
610 !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
611 ObjectSynchronizer::notifyall(lockObject, THREAD);
612 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
613 SystemDictionary_lock->wait();
614 SystemDictionary_lock->unlock();
615 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
616 SystemDictionary_lock->lock();
617 }
618
619 // If the class in is in the placeholder table, class loading is in progress
620 // For cases where the application changes threads to load classes, it
621 // is critical to ClassCircularity detection that we try loading
622 // the superclass on the same thread internally, so we do parallel
623 // super class loading here.
624 // This also is critical in cases where the original thread gets stalled
625 // even in non-circularity situations.
626 // Note: must call resolve_super_or_fail even if null super -
627 // to force placeholder entry creation for this class for circularity detection
628 // Caller must check for pending exception
629 // Returns non-null Klass* if other thread has completed load
630 // and we are done,
631 // If return null Klass* and no pending exception, the caller must load the class
632 InstanceKlass* SystemDictionary::handle_parallel_super_load(
633 Symbol* name, Symbol* superclassname, Handle class_loader,
634 Handle protection_domain, Handle lockObject, TRAPS) {
635
636 ClassLoaderData* loader_data = class_loader_data(class_loader);
637 Dictionary* dictionary = loader_data->dictionary();
638 unsigned int d_hash = dictionary->compute_hash(name);
639 unsigned int p_hash = placeholders()->compute_hash(name);
640 int p_index = placeholders()->hash_to_index(p_hash);
641
642 // superk is not used, resolve_super called for circularity check only
643 // This code is reached in two situations. One if this thread
644 // is loading the same class twice (e.g. ClassCircularity, or
645 // java.lang.instrument).
646 // The second is if another thread started the resolve_super first
647 // and has not yet finished.
648 // In both cases the original caller will clean up the placeholder
649 // entry on error.
650 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
651 superclassname,
652 class_loader,
653 protection_domain,
654 true,
655 CHECK_NULL);
656
657 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
658 // Serial class loaders and bootstrap classloader do wait for superclass loads
659 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
660 MutexLocker mu(THREAD, SystemDictionary_lock);
661 // Check if classloading completed while we were loading superclass or waiting
662 return find_class(d_hash, name, dictionary);
663 }
664
665 // must loop to both handle other placeholder updates
666 // and spurious notifications
667 bool super_load_in_progress = true;
668 PlaceholderEntry* placeholder;
669 while (super_load_in_progress) {
670 MutexLocker mu(THREAD, SystemDictionary_lock);
671 // Check if classloading completed while we were loading superclass or waiting
672 InstanceKlass* check = find_class(d_hash, name, dictionary);
673 if (check != NULL) {
674 // Klass is already loaded, so just return it
675 return check;
676 } else {
677 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
678 if (placeholder && placeholder->super_load_in_progress() ){
679 // We only get here if the application has released the
680 // classloader lock when another thread was in the middle of loading a
681 // superclass/superinterface for this class, and now
682 // this thread is also trying to load this class.
683 // To minimize surprises, the first thread that started to
684 // load a class should be the one to complete the loading
685 // with the classfile it initially expected.
686 // This logic has the current thread wait once it has done
687 // all the superclass/superinterface loading it can, until
688 // the original thread completes the class loading or fails
689 // If it completes we will use the resulting InstanceKlass
690 // which we will find below in the systemDictionary.
691 // We also get here for parallel bootstrap classloader
692 if (class_loader.is_null()) {
693 SystemDictionary_lock->wait();
694 } else {
695 double_lock_wait(lockObject, THREAD);
696 }
697 } else {
698 // If not in SD and not in PH, other thread's load must have failed
699 super_load_in_progress = false;
700 }
701 }
702 }
703 return NULL;
704 }
705
706 void SystemDictionary::post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
707 assert(event != NULL, "invariant");
708 assert(k != NULL, "invariant");
709 assert(event->should_commit(), "invariant");
710 event->set_loadedClass(k);
711 event->set_definingClassLoader(k->class_loader_data());
712 event->set_initiatingClassLoader(init_cld);
713 event->commit();
714 }
715
716
717 // Be careful when modifying this code: once you have run
718 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
719 // you need to find_and_remove it before returning.
720 // So be careful to not exit with a CHECK_ macro betweeen these calls.
721 //
722 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
723 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
724 Handle class_loader,
725 Handle protection_domain,
726 TRAPS) {
727 assert(name != NULL && !Signature::is_array(name) &&
728 !Signature::has_envelope(name), "invalid class name");
729
730 EventClassLoad class_load_start_event;
731
732 HandleMark hm(THREAD);
733
734 // Fix for 4474172; see evaluation for more details
735 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
736 ClassLoaderData* loader_data = register_loader(class_loader);
737 Dictionary* dictionary = loader_data->dictionary();
738 unsigned int d_hash = dictionary->compute_hash(name);
739
740 // Do lookup to see if class already exist and the protection domain
741 // has the right access
742 // This call uses find which checks protection domain already matches
743 // All subsequent calls use find_class, and set has_loaded_class so that
744 // before we return a result we call out to java to check for valid protection domain
745 // to allow returning the Klass* and add it to the pd_set if it is valid
746 {
747 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
748 if (probe != NULL) return probe;
749 }
750
751 // Non-bootstrap class loaders will call out to class loader and
752 // define via jvm/jni_DefineClass which will acquire the
753 // class loader object lock to protect against multiple threads
754 // defining the class in parallel by accident.
755 // This lock must be acquired here so the waiter will find
756 // any successful result in the SystemDictionary and not attempt
757 // the define.
758 // ParallelCapable Classloaders and the bootstrap classloader
759 // do not acquire lock here.
760 bool DoObjectLock = true;
761 if (is_parallelCapable(class_loader)) {
762 DoObjectLock = false;
763 }
764
765 unsigned int p_hash = placeholders()->compute_hash(name);
766 int p_index = placeholders()->hash_to_index(p_hash);
767
768 // Class is not in SystemDictionary so we have to do loading.
769 // Make sure we are synchronized on the class loader before we proceed
770 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
771 check_loader_lock_contention(lockObject, THREAD);
772 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
773
774 // Check again (after locking) if class already exist in SystemDictionary
775 bool class_has_been_loaded = false;
776 bool super_load_in_progress = false;
777 bool havesupername = false;
778 InstanceKlass* k = NULL;
779 PlaceholderEntry* placeholder;
780 Symbol* superclassname = NULL;
781
782 assert(THREAD->can_call_java(),
783 "can not load classes with compiler thread: class=%s, classloader=%s",
784 name->as_C_string(),
785 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
786 {
787 MutexLocker mu(THREAD, SystemDictionary_lock);
788 InstanceKlass* check = find_class(d_hash, name, dictionary);
789 if (check != NULL) {
790 // InstanceKlass is already loaded, so just return it
791 class_has_been_loaded = true;
792 k = check;
793 } else {
794 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
795 if (placeholder && placeholder->super_load_in_progress()) {
796 super_load_in_progress = true;
797 if (placeholder->havesupername() == true) {
798 superclassname = placeholder->supername();
799 havesupername = true;
800 }
801 }
802 }
803 }
804
805 // If the class is in the placeholder table, class loading is in progress
806 if (super_load_in_progress && havesupername==true) {
807 k = handle_parallel_super_load(name,
808 superclassname,
809 class_loader,
810 protection_domain,
811 lockObject, THREAD);
812 if (HAS_PENDING_EXCEPTION) {
813 return NULL;
814 }
815 if (k != NULL) {
816 class_has_been_loaded = true;
817 }
818 }
819
820 bool throw_circularity_error = false;
821 if (!class_has_been_loaded) {
822 bool load_instance_added = false;
823
824 // add placeholder entry to record loading instance class
825 // Five cases:
826 // All cases need to prevent modifying bootclasssearchpath
827 // in parallel with a classload of same classname
828 // Redefineclasses uses existence of the placeholder for the duration
829 // of the class load to prevent concurrent redefinition of not completely
830 // defined classes.
831 // case 1. traditional classloaders that rely on the classloader object lock
832 // - no other need for LOAD_INSTANCE
833 // case 2. traditional classloaders that break the classloader object lock
834 // as a deadlock workaround. Detection of this case requires that
835 // this check is done while holding the classloader object lock,
836 // and that lock is still held when calling classloader's loadClass.
837 // For these classloaders, we ensure that the first requestor
838 // completes the load and other requestors wait for completion.
839 // case 3. Bootstrap classloader - don't own objectLocker
840 // This classloader supports parallelism at the classloader level,
841 // but only allows a single load of a class/classloader pair.
842 // No performance benefit and no deadlock issues.
843 // case 4. parallelCapable user level classloaders - without objectLocker
844 // Allow parallel classloading of a class/classloader pair
845
846 {
847 MutexLocker mu(THREAD, SystemDictionary_lock);
848 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
849 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
850 if (oldprobe) {
851 // only need check_seen_thread once, not on each loop
852 // 6341374 java/lang/Instrument with -Xcomp
853 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
854 throw_circularity_error = true;
855 } else {
856 // case 1: traditional: should never see load_in_progress.
857 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
858
859 // case 3: bootstrap classloader: prevent futile classloading,
860 // wait on first requestor
861 if (class_loader.is_null()) {
862 SystemDictionary_lock->wait();
863 } else {
864 // case 2: traditional with broken classloader lock. wait on first
865 // requestor.
866 double_lock_wait(lockObject, THREAD);
867 }
868 // Check if classloading completed while we were waiting
869 InstanceKlass* check = find_class(d_hash, name, dictionary);
870 if (check != NULL) {
871 // Klass is already loaded, so just return it
872 k = check;
873 class_has_been_loaded = true;
874 }
875 // check if other thread failed to load and cleaned up
876 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
877 }
878 }
879 }
880 }
881 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
882 // case 4: parallelCapable: allow competing threads to try
883 // LOAD_INSTANCE in parallel
884
885 if (!throw_circularity_error && !class_has_been_loaded) {
886 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
887 load_instance_added = true;
888 // For class loaders that do not acquire the classloader object lock,
889 // if they did not catch another thread holding LOAD_INSTANCE,
890 // need a check analogous to the acquire ObjectLocker/find_class
891 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
892 // one final check if the load has already completed
893 // class loaders holding the ObjectLock shouldn't find the class here
894 InstanceKlass* check = find_class(d_hash, name, dictionary);
895 if (check != NULL) {
896 // Klass is already loaded, so return it after checking/adding protection domain
897 k = check;
898 class_has_been_loaded = true;
899 }
900 }
901 }
902
903 // must throw error outside of owning lock
904 if (throw_circularity_error) {
905 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
906 ResourceMark rm(THREAD);
907 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
908 }
909
910 if (!class_has_been_loaded) {
911
912 // Do actual loading
913 k = load_instance_class(name, class_loader, THREAD);
914
915 // If everything was OK (no exceptions, no null return value), and
916 // class_loader is NOT the defining loader, do a little more bookkeeping.
917 if (!HAS_PENDING_EXCEPTION && k != NULL &&
918 k->class_loader() != class_loader()) {
919
920 check_constraints(d_hash, k, class_loader, false, THREAD);
921
922 // Need to check for a PENDING_EXCEPTION again; check_constraints
923 // can throw but we may have to remove entry from the placeholder table below.
924 if (!HAS_PENDING_EXCEPTION) {
925 // Record dependency for non-parent delegation.
926 // This recording keeps the defining class loader of the klass (k) found
927 // from being unloaded while the initiating class loader is loaded
928 // even if the reference to the defining class loader is dropped
929 // before references to the initiating class loader.
930 loader_data->record_dependency(k);
931
932 { // Grabbing the Compile_lock prevents systemDictionary updates
933 // during compilations.
934 MutexLocker mu(THREAD, Compile_lock);
935 update_dictionary(d_hash, p_index, p_hash,
936 k, class_loader, THREAD);
937 }
938
939 if (JvmtiExport::should_post_class_load()) {
940 Thread *thread = THREAD;
941 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
942 JvmtiExport::post_class_load((JavaThread *) thread, k);
943 }
944 }
945 }
946 } // load_instance_class
947
948 if (load_instance_added == true) {
949 // clean up placeholder entries for LOAD_INSTANCE success or error
950 // This brackets the SystemDictionary updates for both defining
951 // and initiating loaders
952 MutexLocker mu(THREAD, SystemDictionary_lock);
953 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
954 SystemDictionary_lock->notify_all();
955 }
956 }
957
958 if (HAS_PENDING_EXCEPTION || k == NULL) {
959 return NULL;
960 }
961 if (class_load_start_event.should_commit()) {
962 post_class_load_event(&class_load_start_event, k, loader_data);
963 }
964 #ifdef ASSERT
965 {
966 ClassLoaderData* loader_data = k->class_loader_data();
967 MutexLocker mu(THREAD, SystemDictionary_lock);
968 InstanceKlass* kk = find_class(name, loader_data);
969 assert(kk == k, "should be present in dictionary");
970 }
971 #endif
972
973 // return if the protection domain in NULL
974 if (protection_domain() == NULL) return k;
975
976 // Check the protection domain has the right access
977 if (dictionary->is_valid_protection_domain(d_hash, name,
978 protection_domain)) {
979 return k;
980 }
981
982 // Verify protection domain. If it fails an exception is thrown
983 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
984
985 return k;
986 }
987
988
989 // This routine does not lock the system dictionary.
990 //
991 // Since readers don't hold a lock, we must make sure that system
992 // dictionary entries are only removed at a safepoint (when only one
993 // thread is running), and are added to in a safe way (all links must
994 // be updated in an MT-safe manner).
995 //
996 // Callers should be aware that an entry could be added just after
997 // _dictionary->bucket(index) is read here, so the caller will not see
998 // the new entry.
999
1000 Klass* SystemDictionary::find(Symbol* class_name,
1001 Handle class_loader,
1002 Handle protection_domain,
1003 TRAPS) {
1004
1005 // The result of this call should be consistent with the result
1006 // of the call to resolve_instance_class_or_null().
1007 // See evaluation 6790209 and 4474172 for more details.
1008 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
1009 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
1010
1011 if (loader_data == NULL) {
1012 // If the ClassLoaderData has not been setup,
1013 // then the class loader has no entries in the dictionary.
1014 return NULL;
1015 }
1016
1017 Dictionary* dictionary = loader_data->dictionary();
1018 unsigned int d_hash = dictionary->compute_hash(class_name);
1019 return dictionary->find(d_hash, class_name,
1020 protection_domain);
1021 }
1022
1023
1024 // Look for a loaded instance or array klass by name. Do not do any loading.
1025 // return NULL in case of error.
1026 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
1027 Handle class_loader,
1028 Handle protection_domain,
1029 TRAPS) {
1030 Klass* k = NULL;
1031 assert(class_name != NULL, "class name must be non NULL");
1032
1033 if (Signature::is_array(class_name)) {
1034 // The name refers to an array. Parse the name.
1035 // dimension and object_key in FieldArrayInfo are assigned as a
1036 // side-effect of this call
1037 SignatureStream ss(class_name, false);
1038 int ndims = ss.skip_array_prefix(); // skip all '['s
1039 BasicType t = ss.type();
1040 if (t != T_OBJECT) {
1041 k = Universe::typeArrayKlassObj(t);
1042 } else {
1043 k = SystemDictionary::find(ss.as_symbol(), class_loader, protection_domain, THREAD);
1044 }
1045 if (k != NULL) {
1046 k = k->array_klass_or_null(ndims);
1047 }
1048 } else {
1049 k = find(class_name, class_loader, protection_domain, THREAD);
1050 }
1051 return k;
1052 }
1053
1054 // Note: this method is much like resolve_from_stream, but
1055 // does not publish the classes via the SystemDictionary.
1056 // Handles Lookup.defineClass hidden, unsafe_DefineAnonymousClass
1057 // and redefineclasses. RedefinedClasses do not add to the class hierarchy.
1058 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1059 Handle class_loader,
1060 ClassFileStream* st,
1061 const ClassLoadInfo& cl_info,
1062 TRAPS) {
1063
1064 EventClassLoad class_load_start_event;
1065 ClassLoaderData* loader_data;
1066 bool is_unsafe_anon_class = cl_info.unsafe_anonymous_host() != NULL;
1067
1068 // - for unsafe anonymous class: create a new CLD whith a class holder that uses
1069 // the same class loader as the unsafe_anonymous_host.
1070 // - for hidden classes that are not strong: create a new CLD that has a class holder and
1071 // whose loader is the Lookup class's loader.
1072 // - for hidden class: add the class to the Lookup class's loader's CLD.
1073 if (is_unsafe_anon_class || cl_info.is_hidden()) {
1074 guarantee(!is_unsafe_anon_class || cl_info.unsafe_anonymous_host()->class_loader() == class_loader(),
1075 "should be NULL or the same");
1076 bool create_mirror_cld = is_unsafe_anon_class || !cl_info.is_strong_hidden();
1077 loader_data = register_loader(class_loader, create_mirror_cld);
1078 } else {
1079 loader_data = ClassLoaderData::class_loader_data(class_loader());
1080 }
1081
1082 assert(st != NULL, "invariant");
1083 assert(st->need_verify(), "invariant");
1084
1085 // Parse stream and create a klass.
1086 // Note that we do this even though this klass might
1087 // already be present in the SystemDictionary, otherwise we would not
1088 // throw potential ClassFormatErrors.
1089
1090 InstanceKlass* k = KlassFactory::create_from_stream(st,
1091 class_name,
1092 loader_data,
1093 cl_info,
1094 CHECK_NULL);
1095
1096 if ((cl_info.is_hidden() || is_unsafe_anon_class) && k != NULL) {
1097 // Hidden classes that are not strong and unsafe anonymous classes must update
1098 // ClassLoaderData holder so that they can be unloaded when the mirror is no
1099 // longer referenced.
1100 if (!cl_info.is_strong_hidden() || is_unsafe_anon_class) {
1101 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1102 }
1103
1104 {
1105 MutexLocker mu_r(THREAD, Compile_lock);
1106
1107 // Add to class hierarchy, initialize vtables, and do possible
1108 // deoptimizations.
1109 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1110 // But, do not add to dictionary.
1111 }
1112
1113 // Rewrite and patch constant pool here.
1114 k->link_class(CHECK_NULL);
1115 if (cl_info.cp_patches() != NULL) {
1116 k->constants()->patch_resolved_references(cl_info.cp_patches());
1117 }
1118
1119 // If it's anonymous, initialize it now, since nobody else will.
1120 if (is_unsafe_anon_class) {
1121 k->eager_initialize(CHECK_NULL);
1122 }
1123
1124 // notify jvmti
1125 if (JvmtiExport::should_post_class_load()) {
1126 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1127 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1128 }
1129 if (class_load_start_event.should_commit()) {
1130 post_class_load_event(&class_load_start_event, k, loader_data);
1131 }
1132 }
1133 assert(is_unsafe_anon_class || NULL == cl_info.cp_patches(),
1134 "cp_patches only found with unsafe_anonymous_host");
1135
1136 return k;
1137 }
1138
1139 // Add a klass to the system from a stream (called by jni_DefineClass and
1140 // JVM_DefineClass).
1141 // Note: class_name can be NULL. In that case we do not know the name of
1142 // the class until we have parsed the stream.
1143
1144 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1145 Handle class_loader,
1146 Handle protection_domain,
1147 ClassFileStream* st,
1148 TRAPS) {
1149
1150 HandleMark hm(THREAD);
1151
1152 // Classloaders that support parallelism, e.g. bootstrap classloader,
1153 // do not acquire lock here
1154 bool DoObjectLock = true;
1155 if (is_parallelCapable(class_loader)) {
1156 DoObjectLock = false;
1157 }
1158
1159 ClassLoaderData* loader_data = register_loader(class_loader);
1160
1161 // Make sure we are synchronized on the class loader before we proceed
1162 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1163 check_loader_lock_contention(lockObject, THREAD);
1164 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1165
1166 assert(st != NULL, "invariant");
1167
1168 // Parse the stream and create a klass.
1169 // Note that we do this even though this klass might
1170 // already be present in the SystemDictionary, otherwise we would not
1171 // throw potential ClassFormatErrors.
1172 InstanceKlass* k = NULL;
1173
1174 #if INCLUDE_CDS
1175 if (!DumpSharedSpaces) {
1176 k = SystemDictionaryShared::lookup_from_stream(class_name,
1177 class_loader,
1178 protection_domain,
1179 st,
1180 CHECK_NULL);
1181 }
1182 #endif
1183
1184 if (k == NULL) {
1185 if (st->buffer() == NULL) {
1186 return NULL;
1187 }
1188 ClassLoadInfo cl_info(protection_domain);
1189 k = KlassFactory::create_from_stream(st, class_name, loader_data, cl_info, CHECK_NULL);
1190 }
1191
1192 assert(k != NULL, "no klass created");
1193 Symbol* h_name = k->name();
1194 assert(class_name == NULL || class_name == h_name, "name mismatch");
1195
1196 // Add class just loaded
1197 // If a class loader supports parallel classloading handle parallel define requests
1198 // find_or_define_instance_class may return a different InstanceKlass
1199 if (is_parallelCapable(class_loader)) {
1200 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1201 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1202 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1203 assert(defined_k != NULL, "Should have a klass if there's no exception");
1204 loader_data->add_to_deallocate_list(k);
1205 k = defined_k;
1206 }
1207 } else {
1208 define_instance_class(k, THREAD);
1209 }
1210
1211 // If defining the class throws an exception register 'k' for cleanup.
1212 if (HAS_PENDING_EXCEPTION) {
1213 assert(k != NULL, "Must have an instance klass here!");
1214 loader_data->add_to_deallocate_list(k);
1215 return NULL;
1216 }
1217
1218 // Make sure we have an entry in the SystemDictionary on success
1219 debug_only( {
1220 MutexLocker mu(THREAD, SystemDictionary_lock);
1221
1222 Klass* check = find_class(h_name, k->class_loader_data());
1223 assert(check == k, "should be present in the dictionary");
1224 } );
1225
1226 return k;
1227 }
1228
1229 #if INCLUDE_CDS
1230 // Load a class for boot loader from the shared spaces. This also
1231 // forces the super class and all interfaces to be loaded.
1232 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1233 PackageEntry* pkg_entry,
1234 TRAPS) {
1235 assert(UseSharedSpaces, "Sanity check");
1236 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1237 if (ik != NULL && ik->is_shared_boot_class()) {
1238 return load_shared_class(ik, Handle(), Handle(), NULL, pkg_entry, THREAD);
1239 }
1240 return NULL;
1241 }
1242
1243 // Check if a shared class can be loaded by the specific classloader.
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
1251 // (1) Check if we are loading into the same loader as in dump time.
1252
1253 if (ik->is_shared_boot_class()) {
1254 if (class_loader() != NULL) {
1255 return false;
1256 }
1257 } else if (ik->is_shared_platform_class()) {
1258 if (class_loader() != java_platform_loader()) {
1259 return false;
1260 }
1261 } else if (ik->is_shared_app_class()) {
1262 if (class_loader() != java_system_loader()) {
1263 return false;
1264 }
1265 } else {
1266 // ik was loaded by a custom loader during dump time
1267 if (class_loader_data(class_loader)->is_builtin_class_loader_data()) {
1268 return false;
1269 } else {
1270 return true;
1271 }
1272 }
1273
1274 // (2) Check if we are loading into the same module from the same location as in dump time.
1275
1276 if (MetaspaceShared::use_optimized_module_handling()) {
1277 // Class visibility has not changed between dump time and run time, so a class
1278 // that was visible (and thus archived) during dump time is always visible during runtime.
1279 assert(SystemDictionary::is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader, THREAD),
1280 "visibility cannot change between dump time and runtime");
1281 return true;
1282 }
1283 return is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader, THREAD);
1284 }
1285
1286 bool SystemDictionary::is_shared_class_visible_impl_old(Symbol* class_name,
1287 InstanceKlass* ik,
1288 PackageEntry* pkg_entry,
1289 Handle class_loader,
1290 SharedClassPathEntry* ent,
1291 ClassLoaderData* loader_data,
1292 TRAPS) {
1293 if (!Universe::is_module_initialized()) {
1294 assert(ent != NULL && ent->is_modules_image(),
1295 "Loading non-bootstrap classes before the module system is initialized");
1296 assert(class_loader.is_null(), "sanity");
1297 return true;
1298 }
1299 // Get the pkg_entry from the classloader
1300 ModuleEntry* mod_entry = NULL;
1301 TempNewSymbol pkg_name = pkg_entry != NULL ? pkg_entry->name() :
1302 ClassLoader::package_from_class_name(class_name);
1303 if (pkg_name != NULL) {
1304 if (loader_data != NULL) {
1305 if (pkg_entry != NULL) {
1306 mod_entry = pkg_entry->module();
1307 // If the archived class is from a module that has been patched at runtime,
1308 // the class cannot be loaded from the archive.
1309 if (mod_entry != NULL && mod_entry->is_patched()) {
1310 return false;
1311 }
1312 }
1313 }
1314 }
1315
1316 if (class_loader.is_null()) {
1317 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1318 // The NULL classloader can load archived class originated from the
1319 // "modules" jimage and the -Xbootclasspath/a. For class from the
1320 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1321 // by the NULL classloader.
1322 if (mod_entry != NULL) {
1323 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1324 // ModuleEntry's location agrees with the archived class' origination.
1325 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1326 return true; // Module class from the "module" jimage
1327 }
1328 }
1329
1330 // If the archived class is not from the "module" jimage, the class can be
1331 // loaded by the NULL classloader if
1332 //
1333 // 1. the class is from the unamed package
1334 // 2. or, the class is not from a module defined in the NULL classloader
1335 // 3. or, the class is from an unamed module
1336 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1337 // the class is from the -Xbootclasspath/a
1338 if (pkg_name == NULL ||
1339 pkg_entry == NULL ||
1340 pkg_entry->in_unnamed_module()) {
1341 assert(mod_entry == NULL ||
1342 mod_entry == loader_data->unnamed_module(),
1343 "the unnamed module is not defined in the classloader");
1344 return true;
1345 }
1346 }
1347 return false;
1348 } else {
1349 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1350 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1351 return res;
1352 }
1353 }
1354
1355 bool SystemDictionary::is_shared_class_visible_impl(Symbol* class_name,
1356 InstanceKlass* ik,
1357 PackageEntry* pkg_entry,
1358 Handle class_loader, TRAPS) {
1359 int scp_index = ik->shared_classpath_index();
1360 assert(scp_index >= 0, "must be");
1361 SharedClassPathEntry* scp_entry = FileMapInfo::shared_path(scp_index);
1362 if (!Universe::is_module_initialized()) {
1363 assert(scp_entry != NULL && scp_entry->is_modules_image(),
1364 "Loading non-bootstrap classes before the module system is initialized");
1365 assert(class_loader.is_null(), "sanity");
1366 return true;
1367 }
1368
1369 ModuleEntry* mod_entry = (pkg_entry == NULL) ? NULL : pkg_entry->module();
1370 bool should_be_in_named_module = (mod_entry != NULL && mod_entry->is_named());
1371 bool was_archived_from_named_module = scp_entry->in_named_module();
1372 bool visible;
1373
1374 if (was_archived_from_named_module) {
1375 if (should_be_in_named_module) {
1376 // Is the module loaded from the same location as during dump time?
1377 visible = mod_entry->shared_path_index() == scp_index;
1378 } else {
1379 // During dump time, this class was in a named module, but at run time, this class should be
1380 // in an unnamed module.
1381 visible = false;
1382 }
1383 } else {
1384 if (should_be_in_named_module) {
1385 // During dump time, this class was in an unnamed, but at run time, this class should be
1386 // in a named module.
1387 visible = false;
1388 } else {
1389 visible = true;
1390 }
1391 }
1392
1393 DEBUG_ONLY(bool visible_old = is_shared_class_visible_impl_old(class_name,
1394 ik,
1395 pkg_entry,
1396 class_loader,
1397 scp_entry,
1398 class_loader_data(class_loader), CHECK_0));
1399 assert(visible == visible_old, "must be!");
1400 return visible;
1401 }
1402
1403 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1404 Handle class_loader, Handle protection_domain,
1405 bool is_superclass, TRAPS) {
1406 assert(super_type->is_shared(), "must be");
1407
1408 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1409 class_loader, protection_domain, is_superclass, CHECK_0);
1410 if (found == super_type) {
1411 return true;
1412 } else {
1413 // The dynamically resolved super type is not the same as the one we used during dump time,
1414 // so we cannot use the child class.
1415 return false;
1416 }
1417 }
1418
1419 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1420 Handle protection_domain, TRAPS) {
1421 // Check the superclass and interfaces. They must be the same
1422 // as in dump time, because the layout of <ik> depends on
1423 // the specific layout of ik->super() and ik->local_interfaces().
1424 //
1425 // If unexpected superclass or interfaces are found, we cannot
1426 // load <ik> from the shared archive.
1427
1428 if (ik->super() != NULL &&
1429 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1430 class_loader, protection_domain, true, THREAD)) {
1431 return false;
1432 }
1433
1434 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1435 int num_interfaces = interfaces->length();
1436 for (int index = 0; index < num_interfaces; index++) {
1437 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1438 return false;
1439 }
1440 }
1441
1442 return true;
1443 }
1444
1445 InstanceKlass* SystemDictionary::load_shared_lambda_proxy_class(InstanceKlass* ik,
1446 Handle class_loader,
1447 Handle protection_domain,
1448 PackageEntry* pkg_entry,
1449 TRAPS) {
1450 InstanceKlass* shared_nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1451 assert(shared_nest_host->is_shared(), "nest host must be in CDS archive");
1452 Symbol* cn = shared_nest_host->name();
1453 Klass *s = resolve_or_fail(cn, class_loader, protection_domain, true, CHECK_NULL);
1454 if (s != shared_nest_host) {
1455 // The dynamically resolved nest_host is not the same as the one we used during dump time,
1456 // so we cannot use ik.
1457 return NULL;
1458 } else {
1459 assert(s->is_shared(), "must be");
1460 }
1461
1462 // The lambda proxy class and its nest host have the same class loader and class loader data,
1463 // as verified in SystemDictionaryShared::add_lambda_proxy_class()
1464 assert(shared_nest_host->class_loader() == class_loader(), "mismatched class loader");
1465 assert(shared_nest_host->class_loader_data() == ClassLoaderData::class_loader_data(class_loader()), "mismatched class loader data");
1466 ik->set_nest_host(shared_nest_host, THREAD);
1467
1468 InstanceKlass* loaded_ik = load_shared_class(ik, class_loader, protection_domain, NULL, pkg_entry, CHECK_NULL);
1469
1470 assert(shared_nest_host->is_same_class_package(ik),
1471 "lambda proxy class and its nest host must be in the same package");
1472
1473 return loaded_ik;
1474 }
1475
1476 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1477 Handle class_loader,
1478 Handle protection_domain,
1479 const ClassFileStream *cfs,
1480 PackageEntry* pkg_entry,
1481 TRAPS) {
1482 assert(ik != NULL, "sanity");
1483 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1484 Symbol* class_name = ik->name();
1485
1486 bool visible = is_shared_class_visible(
1487 class_name, ik, pkg_entry, class_loader, CHECK_NULL);
1488 if (!visible) {
1489 return NULL;
1490 }
1491
1492 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1493 return NULL;
1494 }
1495
1496 InstanceKlass* new_ik = NULL;
1497 // CFLH check is skipped for VM hidden or anonymous classes (see KlassFactory::create_from_stream).
1498 // It will be skipped for shared VM hidden lambda proxy classes.
1499 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1500 new_ik = KlassFactory::check_shared_class_file_load_hook(
1501 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1502 }
1503 if (new_ik != NULL) {
1504 // The class is changed by CFLH. Return the new class. The shared class is
1505 // not used.
1506 return new_ik;
1507 }
1508
1509 // Adjust methods to recover missing data. They need addresses for
1510 // interpreter entry points and their default native method address
1511 // must be reset.
1512
1513 // Updating methods must be done under a lock so multiple
1514 // threads don't update these in parallel
1515 //
1516 // Shared classes are all currently loaded by either the bootstrap or
1517 // internal parallel class loaders, so this will never cause a deadlock
1518 // on a custom class loader lock.
1519
1520 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1521 {
1522 HandleMark hm(THREAD);
1523 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1524 check_loader_lock_contention(lockObject, THREAD);
1525 ObjectLocker ol(lockObject, THREAD, true);
1526 // prohibited package check assumes all classes loaded from archive call
1527 // restore_unshareable_info which calls ik->set_package()
1528 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1529 }
1530
1531 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1532 return ik;
1533 }
1534
1535 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1536 ik->print_class_load_logging(loader_data, NULL, NULL);
1537
1538 // For boot loader, ensure that GetSystemPackage knows that a class in this
1539 // package was loaded.
1540 if (loader_data->is_the_null_class_loader_data()) {
1541 int path_index = ik->shared_classpath_index();
1542 ik->set_classpath_index(path_index, THREAD);
1543 }
1544
1545 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1546 // Only dump the classes that can be stored into CDS archive
1547 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1548 ResourceMark rm(THREAD);
1549 classlist_file->print_cr("%s", ik->name()->as_C_string());
1550 classlist_file->flush();
1551 }
1552 }
1553
1554 // notify a class loaded from shared object
1555 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1556
1557 ik->set_has_passed_fingerprint_check(false);
1558 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1559 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1560 uint64_t cds_fp = ik->get_stored_fingerprint();
1561 if (aot_fp != 0 && aot_fp == cds_fp) {
1562 // This class matches with a class saved in an AOT library
1563 ik->set_has_passed_fingerprint_check(true);
1564 } else {
1565 if (log_is_enabled(Info, class, fingerprint)) {
1566 ResourceMark rm(THREAD);
1567 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1568 }
1569 }
1570 }
1571 }
1572
1573 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1574 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1575 assert(klass->is_shared(), "Must be shared class");
1576 if (klass->class_loader_data() != NULL) {
1577 return;
1578 }
1579
1580 // add super and interfaces first
1581 Klass* super = klass->super();
1582 if (super != NULL && super->class_loader_data() == NULL) {
1583 assert(super->is_instance_klass(), "Super should be instance klass");
1584 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1585 }
1586
1587 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1588 for (int i = 0; i < ifs->length(); i++) {
1589 InstanceKlass* ik = ifs->at(i);
1590 if (ik->class_loader_data() == NULL) {
1591 quick_resolve(ik, loader_data, domain, CHECK);
1592 }
1593 }
1594
1595 klass->restore_unshareable_info(loader_data, domain, NULL, THREAD);
1596 load_shared_class_misc(klass, loader_data, CHECK);
1597 Dictionary* dictionary = loader_data->dictionary();
1598 unsigned int hash = dictionary->compute_hash(klass->name());
1599 dictionary->add_klass(hash, klass->name(), klass);
1600 add_to_hierarchy(klass, CHECK);
1601 assert(klass->is_loaded(), "Must be in at least loaded state");
1602 }
1603 #endif // INCLUDE_CDS
1604
1605 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1606
1607 if (class_loader.is_null()) {
1608 ResourceMark rm(THREAD);
1609 PackageEntry* pkg_entry = NULL;
1610 bool search_only_bootloader_append = false;
1611 ClassLoaderData *loader_data = class_loader_data(class_loader);
1612
1613 // Find the package in the boot loader's package entry table.
1614 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1615 if (pkg_name != NULL) {
1616 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1617 }
1618
1619 // Prior to attempting to load the class, enforce the boot loader's
1620 // visibility boundaries.
1621 if (!Universe::is_module_initialized()) {
1622 // During bootstrapping, prior to module initialization, any
1623 // class attempting to be loaded must be checked against the
1624 // java.base packages in the boot loader's PackageEntryTable.
1625 // No class outside of java.base is allowed to be loaded during
1626 // this bootstrapping window.
1627 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1628 // Class is either in the unnamed package or in
1629 // a named package within the unnamed module. Either
1630 // case is outside of java.base, do not attempt to
1631 // load the class post java.base definition. If
1632 // java.base has not been defined, let the class load
1633 // and its package will be checked later by
1634 // ModuleEntryTable::verify_javabase_packages.
1635 if (ModuleEntryTable::javabase_defined()) {
1636 return NULL;
1637 }
1638 } else {
1639 // Check that the class' package is defined within java.base.
1640 ModuleEntry* mod_entry = pkg_entry->module();
1641 Symbol* mod_entry_name = mod_entry->name();
1642 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1643 return NULL;
1644 }
1645 }
1646 } else {
1647 // After the module system has been initialized, check if the class'
1648 // package is in a module defined to the boot loader.
1649 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1650 // Class is either in the unnamed package, in a named package
1651 // within a module not defined to the boot loader or in a
1652 // a named package within the unnamed module. In all cases,
1653 // limit visibility to search for the class only in the boot
1654 // loader's append path.
1655 if (!ClassLoader::has_bootclasspath_append()) {
1656 // If there is no bootclasspath append entry, no need to continue
1657 // searching.
1658 return NULL;
1659 }
1660 search_only_bootloader_append = true;
1661 }
1662 }
1663
1664 // Prior to bootstrapping's module initialization, never load a class outside
1665 // of the boot loader's module path
1666 assert(Universe::is_module_initialized() ||
1667 !search_only_bootloader_append,
1668 "Attempt to load a class outside of boot loader's module path");
1669
1670 // Search for classes in the CDS archive.
1671 InstanceKlass* k = NULL;
1672
1673 #if INCLUDE_CDS
1674 if (UseSharedSpaces)
1675 {
1676 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1677 k = load_shared_boot_class(class_name, pkg_entry, THREAD);
1678 }
1679 #endif
1680
1681 if (k == NULL) {
1682 // Use VM class loader
1683 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1684 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1685 }
1686
1687 // find_or_define_instance_class may return a different InstanceKlass
1688 if (k != NULL) {
1689 InstanceKlass* defined_k =
1690 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1691 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1692 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1693 assert(defined_k != NULL, "Should have a klass if there's no exception");
1694 loader_data->add_to_deallocate_list(k);
1695 k = defined_k;
1696 } else if (HAS_PENDING_EXCEPTION) {
1697 loader_data->add_to_deallocate_list(k);
1698 return NULL;
1699 }
1700 }
1701 return k;
1702 } else {
1703 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1704 ResourceMark rm(THREAD);
1705
1706 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1707 JavaThread* jt = (JavaThread*) THREAD;
1708
1709 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1710 ClassLoader::perf_app_classload_selftime(),
1711 ClassLoader::perf_app_classload_count(),
1712 jt->get_thread_stat()->perf_recursion_counts_addr(),
1713 jt->get_thread_stat()->perf_timers_addr(),
1714 PerfClassTraceTime::CLASS_LOAD);
1715
1716 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1717 // Translate to external class name format, i.e., convert '/' chars to '.'
1718 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1719
1720 JavaValue result(T_OBJECT);
1721
1722 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1723
1724 // Call public unsynchronized loadClass(String) directly for all class loaders.
1725 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1726 // acquire a class-name based lock rather than the class loader object lock.
1727 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1728 JavaCalls::call_virtual(&result,
1729 class_loader,
1730 spec_klass,
1731 vmSymbols::loadClass_name(),
1732 vmSymbols::string_class_signature(),
1733 string,
1734 CHECK_NULL);
1735
1736 assert(result.get_type() == T_OBJECT, "just checking");
1737 oop obj = (oop) result.get_jobject();
1738
1739 // Primitive classes return null since forName() can not be
1740 // used to obtain any of the Class objects representing primitives or void
1741 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1742 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1743 // For user defined Java class loaders, check that the name returned is
1744 // the same as that requested. This check is done for the bootstrap
1745 // loader when parsing the class file.
1746 if (class_name == k->name()) {
1747 return k;
1748 }
1749 }
1750 // Class is not found or has the wrong name, return NULL
1751 return NULL;
1752 }
1753 }
1754
1755 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1756 EventClassDefine event;
1757 if (event.should_commit()) {
1758 event.set_definedClass(k);
1759 event.set_definingClassLoader(def_cld);
1760 event.commit();
1761 }
1762 }
1763
1764 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1765
1766 HandleMark hm(THREAD);
1767 ClassLoaderData* loader_data = k->class_loader_data();
1768 Handle class_loader_h(THREAD, loader_data->class_loader());
1769
1770 // for bootstrap and other parallel classloaders don't acquire lock,
1771 // use placeholder token
1772 // If a parallelCapable class loader calls define_instance_class instead of
1773 // find_or_define_instance_class to get here, we have a timing
1774 // hole with systemDictionary updates and check_constraints
1775 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1776 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1777 compute_loader_lock_object(class_loader_h, THREAD)),
1778 "define called without lock");
1779 }
1780
1781 // Check class-loading constraints. Throw exception if violation is detected.
1782 // Grabs and releases SystemDictionary_lock
1783 // The check_constraints/find_class call and update_dictionary sequence
1784 // must be "atomic" for a specific class/classloader pair so we never
1785 // define two different instanceKlasses for that class/classloader pair.
1786 // Existing classloaders will call define_instance_class with the
1787 // classloader lock held
1788 // Parallel classloaders will call find_or_define_instance_class
1789 // which will require a token to perform the define class
1790 Symbol* name_h = k->name();
1791 Dictionary* dictionary = loader_data->dictionary();
1792 unsigned int d_hash = dictionary->compute_hash(name_h);
1793 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1794
1795 // Register class just loaded with class loader (placed in ArrayList)
1796 // Note we do this before updating the dictionary, as this can
1797 // fail with an OutOfMemoryError (if it does, we will *not* put this
1798 // class in the dictionary and will not update the class hierarchy).
1799 // JVMTI FollowReferences needs to find the classes this way.
1800 if (k->class_loader() != NULL) {
1801 methodHandle m(THREAD, Universe::loader_addClass_method());
1802 JavaValue result(T_VOID);
1803 JavaCallArguments args(class_loader_h);
1804 args.push_oop(Handle(THREAD, k->java_mirror()));
1805 JavaCalls::call(&result, m, &args, CHECK);
1806 }
1807
1808 // Add the new class. We need recompile lock during update of CHA.
1809 {
1810 unsigned int p_hash = placeholders()->compute_hash(name_h);
1811 int p_index = placeholders()->hash_to_index(p_hash);
1812
1813 MutexLocker mu_r(THREAD, Compile_lock);
1814
1815 // Add to class hierarchy, initialize vtables, and do possible
1816 // deoptimizations.
1817 add_to_hierarchy(k, CHECK); // No exception, but can block
1818
1819 // Add to systemDictionary - so other classes can see it.
1820 // Grabs and releases SystemDictionary_lock
1821 update_dictionary(d_hash, p_index, p_hash,
1822 k, class_loader_h, THREAD);
1823 }
1824 k->eager_initialize(THREAD);
1825
1826 // notify jvmti
1827 if (JvmtiExport::should_post_class_load()) {
1828 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1829 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1830
1831 }
1832 post_class_define_event(k, loader_data);
1833 }
1834
1835 // Support parallel classloading
1836 // All parallel class loaders, including bootstrap classloader
1837 // lock a placeholder entry for this class/class_loader pair
1838 // to allow parallel defines of different classes for this class loader
1839 // With AllowParallelDefine flag==true, in case they do not synchronize around
1840 // FindLoadedClass/DefineClass, calls, we check for parallel
1841 // loading for them, wait if a defineClass is in progress
1842 // and return the initial requestor's results
1843 // This flag does not apply to the bootstrap classloader.
1844 // With AllowParallelDefine flag==false, call through to define_instance_class
1845 // which will throw LinkageError: duplicate class definition.
1846 // False is the requested default.
1847 // For better performance, the class loaders should synchronize
1848 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1849 // potentially waste time reading and parsing the bytestream.
1850 // Note: VM callers should ensure consistency of k/class_name,class_loader
1851 // Be careful when modifying this code: once you have run
1852 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1853 // you need to find_and_remove it before returning.
1854 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1855 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1856 InstanceKlass* k, TRAPS) {
1857
1858 Symbol* name_h = k->name(); // passed in class_name may be null
1859 ClassLoaderData* loader_data = class_loader_data(class_loader);
1860 Dictionary* dictionary = loader_data->dictionary();
1861
1862 unsigned int d_hash = dictionary->compute_hash(name_h);
1863
1864 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1865 unsigned int p_hash = placeholders()->compute_hash(name_h);
1866 int p_index = placeholders()->hash_to_index(p_hash);
1867 PlaceholderEntry* probe;
1868
1869 {
1870 MutexLocker mu(THREAD, SystemDictionary_lock);
1871 // First check if class already defined
1872 if (is_parallelDefine(class_loader)) {
1873 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1874 if (check != NULL) {
1875 return check;
1876 }
1877 }
1878
1879 // Acquire define token for this class/classloader
1880 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1881 // Wait if another thread defining in parallel
1882 // All threads wait - even those that will throw duplicate class: otherwise
1883 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1884 // if other thread has not finished updating dictionary
1885 while (probe->definer() != NULL) {
1886 SystemDictionary_lock->wait();
1887 }
1888 // Only special cases allow parallel defines and can use other thread's results
1889 // Other cases fall through, and may run into duplicate defines
1890 // caught by finding an entry in the SystemDictionary
1891 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1892 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1893 SystemDictionary_lock->notify_all();
1894 #ifdef ASSERT
1895 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1896 assert(check != NULL, "definer missed recording success");
1897 #endif
1898 return probe->instance_klass();
1899 } else {
1900 // This thread will define the class (even if earlier thread tried and had an error)
1901 probe->set_definer(THREAD);
1902 }
1903 }
1904
1905 define_instance_class(k, THREAD);
1906
1907 Handle linkage_exception = Handle(); // null handle
1908
1909 // definer must notify any waiting threads
1910 {
1911 MutexLocker mu(THREAD, SystemDictionary_lock);
1912 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1913 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1914 if (probe != NULL) {
1915 if (HAS_PENDING_EXCEPTION) {
1916 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1917 CLEAR_PENDING_EXCEPTION;
1918 } else {
1919 probe->set_instance_klass(k);
1920 }
1921 probe->set_definer(NULL);
1922 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1923 SystemDictionary_lock->notify_all();
1924 }
1925 }
1926
1927 // Can't throw exception while holding lock due to rank ordering
1928 if (linkage_exception() != NULL) {
1929 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1930 }
1931
1932 return k;
1933 }
1934
1935 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1936 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1937 if (class_loader.is_null()) {
1938 return Handle(THREAD, _system_loader_lock_obj.resolve());
1939 } else {
1940 return class_loader;
1941 }
1942 }
1943
1944 // This method is added to check how often we have to wait to grab loader
1945 // lock. The results are being recorded in the performance counters defined in
1946 // ClassLoader::_sync_systemLoaderLockContentionRate and
1947 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1948 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1949 if (!UsePerfData) {
1950 return;
1951 }
1952
1953 assert(!loader_lock.is_null(), "NULL lock object");
1954
1955 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1956 == ObjectSynchronizer::owner_other) {
1957 // contention will likely happen, so increment the corresponding
1958 // contention counter.
1959 if (loader_lock() == _system_loader_lock_obj.resolve()) {
1960 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1961 } else {
1962 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1963 }
1964 }
1965 }
1966
1967 // ----------------------------------------------------------------------------
1968 // Lookup
1969
1970 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1971 Symbol* class_name,
1972 Dictionary* dictionary) {
1973 assert_locked_or_safepoint(SystemDictionary_lock);
1974 int index = dictionary->hash_to_index(hash);
1975 return dictionary->find_class(index, hash, class_name);
1976 }
1977
1978
1979 // Basic find on classes in the midst of being loaded
1980 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1981 ClassLoaderData* loader_data) {
1982 assert_locked_or_safepoint(SystemDictionary_lock);
1983 unsigned int p_hash = placeholders()->compute_hash(class_name);
1984 int p_index = placeholders()->hash_to_index(p_hash);
1985 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1986 }
1987
1988
1989 // Used for assertions and verification only
1990 // Precalculating the hash and index is an optimization because there are many lookups
1991 // before adding the class.
1992 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1993 assert_locked_or_safepoint(SystemDictionary_lock);
1994 #ifndef ASSERT
1995 guarantee(VerifyBeforeGC ||
1996 VerifyDuringGC ||
1997 VerifyBeforeExit ||
1998 VerifyDuringStartup ||
1999 VerifyAfterGC, "too expensive");
2000 #endif
2001
2002 Dictionary* dictionary = loader_data->dictionary();
2003 unsigned int d_hash = dictionary->compute_hash(class_name);
2004 return find_class(d_hash, class_name, dictionary);
2005 }
2006
2007
2008 // ----------------------------------------------------------------------------
2009 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
2010 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
2011 // before a new class is used.
2012
2013 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
2014 assert(k != NULL, "just checking");
2015 if (Universe::is_fully_initialized()) {
2016 assert_locked_or_safepoint(Compile_lock);
2017 }
2018
2019 k->set_init_state(InstanceKlass::loaded);
2020 // make sure init_state store is already done.
2021 // The compiler reads the hierarchy outside of the Compile_lock.
2022 // Access ordering is used to add to hierarchy.
2023
2024 // Link into hierachy.
2025 k->append_to_sibling_list(); // add to superklass/sibling list
2026 k->process_interfaces(THREAD); // handle all "implements" declarations
2027
2028 // Now flush all code that depended on old class hierarchy.
2029 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
2030 if (Universe::is_fully_initialized()) {
2031 CodeCache::flush_dependents_on(k);
2032 }
2033 }
2034
2035 // ----------------------------------------------------------------------------
2036 // GC support
2037
2038 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
2039 // Note: anonymous classes are not in the SD.
2040 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
2041
2042 bool unloading_occurred;
2043 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
2044 {
2045 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
2046 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
2047 // First, mark for unload all ClassLoaderData referencing a dead class loader.
2048 unloading_occurred = ClassLoaderDataGraph::do_unloading();
2049 if (unloading_occurred) {
2050 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
2051 JFR_ONLY(Jfr::on_unloading_classes();)
2052
2053 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
2054 ClassLoaderDataGraph::clean_module_and_package_info();
2055 constraints()->purge_loader_constraints();
2056 resolution_errors()->purge_resolution_errors();
2057 }
2058 }
2059
2060 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
2061
2062 if (unloading_occurred) {
2063 SymbolTable::trigger_cleanup();
2064
2065 // Oops referenced by the protection domain cache table may get unreachable independently
2066 // of the class loader (eg. cached protection domain oops). So we need to
2067 // explicitly unlink them here.
2068 // All protection domain oops are linked to the caller class, so if nothing
2069 // unloads, this is not needed.
2070 _pd_cache_table->trigger_cleanup();
2071 }
2072
2073 return unloading_occurred;
2074 }
2075
2076 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
2077 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
2078 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
2079 it->push(well_known_klass_addr((WKID)id));
2080 }
2081 }
2082
2083 void SystemDictionary::methods_do(void f(Method*)) {
2084 // Walk methods in loaded classes
2085 MutexLocker ml(ClassLoaderDataGraph_lock);
2086 ClassLoaderDataGraph::methods_do(f);
2087 // Walk method handle intrinsics
2088 invoke_method_table()->methods_do(f);
2089 }
2090
2091 // ----------------------------------------------------------------------------
2092 // Initialization
2093
2094 void SystemDictionary::initialize(TRAPS) {
2095 // Allocate arrays
2096 _placeholders = new PlaceholderTable(_placeholder_table_size);
2097 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2098 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2099 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2100 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2101
2102 // Allocate private object used as system class loader lock
2103 oop lock_obj = oopFactory::new_intArray(0, CHECK);
2104 _system_loader_lock_obj = OopHandle::create(lock_obj);
2105
2106 // Initialize basic classes
2107 resolve_well_known_classes(CHECK);
2108 }
2109
2110 // Compact table of directions on the initialization of klasses:
2111 static const short wk_init_info[] = {
2112 #define WK_KLASS_INIT_INFO(name, symbol) \
2113 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
2114
2115 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2116 #undef WK_KLASS_INIT_INFO
2117 0
2118 };
2119
2120 #ifdef ASSERT
2121 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
2122 int sid;
2123 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
2124 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2125 if (class_name == symbol) {
2126 return true;
2127 }
2128 }
2129 return false;
2130 }
2131 #endif
2132
2133 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
2134 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2135 int sid = wk_init_info[id - FIRST_WKID];
2136 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2137 InstanceKlass** klassp = &_well_known_klasses[id];
2138
2139 #if INCLUDE_CDS
2140 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
2141 InstanceKlass* k = *klassp;
2142 assert(k->is_shared_boot_class(), "must be");
2143
2144 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
2145 quick_resolve(k, loader_data, Handle(), CHECK_false);
2146 return true;
2147 }
2148 #endif // INCLUDE_CDS
2149
2150 if (!is_wk_klass_loaded(*klassp)) {
2151 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
2152 (*klassp) = InstanceKlass::cast(k);
2153 }
2154 return ((*klassp) != NULL);
2155 }
2156
2157 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2158 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2159 for (int id = (int)start_id; id < (int)limit_id; id++) {
2160 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2161 resolve_wk_klass((WKID)id, CHECK);
2162 }
2163
2164 // move the starting value forward to the limit:
2165 start_id = limit_id;
2166 }
2167
2168 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2169 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
2170
2171 // Create the ModuleEntry for java.base. This call needs to be done here,
2172 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2173 ClassLoader::classLoader_init2(CHECK);
2174
2175 // Preload commonly used klasses
2176 WKID scan = FIRST_WKID;
2177 // first do Object, then String, Class
2178 #if INCLUDE_CDS
2179 if (UseSharedSpaces) {
2180 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2181
2182 // It's unsafe to access the archived heap regions before they
2183 // are fixed up, so we must do the fixup as early as possible
2184 // before the archived java objects are accessed by functions
2185 // such as java_lang_Class::restore_archived_mirror and
2186 // ConstantPool::restore_unshareable_info (restores the archived
2187 // resolved_references array object).
2188 //
2189 // HeapShared::fixup_mapped_heap_regions() fills the empty
2190 // spaces in the archived heap regions and may use
2191 // SystemDictionary::Object_klass(), so we can do this only after
2192 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2193 // call. No mirror objects are accessed/restored in the above call.
2194 // Mirrors are restored after java.lang.Class is loaded.
2195 HeapShared::fixup_mapped_heap_regions();
2196
2197 // Initialize the constant pool for the Object_class
2198 assert(Object_klass()->is_shared(), "must be");
2199 Object_klass()->constants()->restore_unshareable_info(CHECK);
2200 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2201 } else
2202 #endif
2203 {
2204 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2205 }
2206
2207 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2208
2209 java_lang_Object::register_natives(CHECK);
2210
2211 // Calculate offsets for String and Class classes since they are loaded and
2212 // can be used after this point.
2213 java_lang_String::compute_offsets();
2214 java_lang_Class::compute_offsets();
2215
2216 // Fixup mirrors for classes loaded before java.lang.Class.
2217 Universe::initialize_basic_type_mirrors(CHECK);
2218 Universe::fixup_mirrors(CHECK);
2219
2220 // do a bunch more:
2221 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2222
2223 // The offsets for jlr.Reference must be computed before
2224 // InstanceRefKlass::update_nonstatic_oop_maps is called. That function uses
2225 // the offsets to remove the referent and discovered fields from the oop maps,
2226 // as they are treated in a special way by the GC. Removing these oops from the
2227 // oop maps must be done before the usual subclasses of jlr.Reference are loaded.
2228 java_lang_ref_Reference::compute_offsets();
2229
2230 // Preload ref klasses and set reference types
2231 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2232 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2233
2234 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2235 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2236 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2237 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2238 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2239
2240 // JSR 292 classes
2241 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2242 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2243 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2244 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2245 WKID last = WKID_LIMIT;
2246 resolve_wk_klasses_until(last, scan, CHECK);
2247
2248 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2249 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2250 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2251 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2252 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2253 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2254 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2255 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2256 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2257 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2258
2259 #ifdef ASSERT
2260 if (UseSharedSpaces) {
2261 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2262 "All well known classes must be resolved in JVMTI early phase"));
2263 for (int i = FIRST_WKID; i < last; i++) {
2264 InstanceKlass* k = _well_known_klasses[i];
2265 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2266 }
2267 }
2268 #endif
2269 }
2270
2271 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2272 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2273 BasicType SystemDictionary::box_klass_type(Klass* k) {
2274 assert(k != NULL, "");
2275 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2276 if (_box_klasses[i] == k)
2277 return (BasicType)i;
2278 }
2279 return T_OBJECT;
2280 }
2281
2282 // Constraints on class loaders. The details of the algorithm can be
2283 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2284 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2285 // that the dictionary needs to maintain a set of contraints that
2286 // must be satisfied by all classes in the dictionary.
2287 // if defining is true, then LinkageError if already in dictionary
2288 // if initiating loader, then ok if InstanceKlass matches existing entry
2289
2290 void SystemDictionary::check_constraints(unsigned int d_hash,
2291 InstanceKlass* k,
2292 Handle class_loader,
2293 bool defining,
2294 TRAPS) {
2295 ResourceMark rm(THREAD);
2296 stringStream ss;
2297 bool throwException = false;
2298
2299 {
2300 Symbol *name = k->name();
2301 ClassLoaderData *loader_data = class_loader_data(class_loader);
2302
2303 MutexLocker mu(THREAD, SystemDictionary_lock);
2304
2305 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2306 if (check != NULL) {
2307 // If different InstanceKlass - duplicate class definition,
2308 // else - ok, class loaded by a different thread in parallel.
2309 // We should only have found it if it was done loading and ok to use.
2310 // The dictionary only holds instance classes, placeholders
2311 // also hold array classes.
2312
2313 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2314 if ((defining == true) || (k != check)) {
2315 throwException = true;
2316 ss.print("loader %s", loader_data->loader_name_and_id());
2317 ss.print(" attempted duplicate %s definition for %s. (%s)",
2318 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2319 } else {
2320 return;
2321 }
2322 }
2323
2324 #ifdef ASSERT
2325 Symbol* ph_check = find_placeholder(name, loader_data);
2326 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2327 #endif
2328
2329 if (throwException == false) {
2330 if (constraints()->check_or_update(k, class_loader, name) == false) {
2331 throwException = true;
2332 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2333 ss.print(" wants to load %s %s.",
2334 k->external_kind(), k->external_name());
2335 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2336 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2337 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2338 existing_klass->external_kind(),
2339 existing_klass->class_loader_data()->loader_name_and_id(),
2340 existing_klass->class_in_module_of_loader(false, true));
2341 } else {
2342 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2343 }
2344 }
2345 }
2346 }
2347
2348 // Throw error now if needed (cannot throw while holding
2349 // SystemDictionary_lock because of rank ordering)
2350 if (throwException == true) {
2351 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2352 }
2353 }
2354
2355 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2356 // have been called.
2357 void SystemDictionary::update_dictionary(unsigned int d_hash,
2358 int p_index, unsigned int p_hash,
2359 InstanceKlass* k,
2360 Handle class_loader,
2361 TRAPS) {
2362 // Compile_lock prevents systemDictionary updates during compilations
2363 assert_locked_or_safepoint(Compile_lock);
2364 Symbol* name = k->name();
2365 ClassLoaderData *loader_data = class_loader_data(class_loader);
2366
2367 {
2368 MutexLocker mu1(THREAD, SystemDictionary_lock);
2369
2370 // Make a new dictionary entry.
2371 Dictionary* dictionary = loader_data->dictionary();
2372 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2373 if (sd_check == NULL) {
2374 dictionary->add_klass(d_hash, name, k);
2375 }
2376 #ifdef ASSERT
2377 sd_check = find_class(d_hash, name, dictionary);
2378 assert (sd_check != NULL, "should have entry in dictionary");
2379 // Note: there may be a placeholder entry: for circularity testing
2380 // or for parallel defines
2381 #endif
2382 SystemDictionary_lock->notify_all();
2383 }
2384 }
2385
2386
2387 // Try to find a class name using the loader constraints. The
2388 // loader constraints might know about a class that isn't fully loaded
2389 // yet and these will be ignored.
2390 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2391 Symbol* class_name, Handle class_loader, TRAPS) {
2392
2393 // First see if it has been loaded directly.
2394 // Force the protection domain to be null. (This removes protection checks.)
2395 Handle no_protection_domain;
2396 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2397 no_protection_domain, CHECK_NULL);
2398 if (klass != NULL)
2399 return klass;
2400
2401 // Now look to see if it has been loaded elsewhere, and is subject to
2402 // a loader constraint that would require this loader to return the
2403 // klass that is already loaded.
2404 if (Signature::is_array(class_name)) {
2405 // For array classes, their Klass*s are not kept in the
2406 // constraint table. The element Klass*s are.
2407 SignatureStream ss(class_name, false);
2408 int ndims = ss.skip_array_prefix(); // skip all '['s
2409 BasicType t = ss.type();
2410 if (t != T_OBJECT) {
2411 klass = Universe::typeArrayKlassObj(t);
2412 } else {
2413 MutexLocker mu(THREAD, SystemDictionary_lock);
2414 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2415 }
2416 // If element class already loaded, allocate array klass
2417 if (klass != NULL) {
2418 klass = klass->array_klass_or_null(ndims);
2419 }
2420 } else {
2421 MutexLocker mu(THREAD, SystemDictionary_lock);
2422 // Non-array classes are easy: simply check the constraint table.
2423 klass = constraints()->find_constrained_klass(class_name, class_loader);
2424 }
2425
2426 return klass;
2427 }
2428
2429 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2430 Klass* klass_being_linked,
2431 Handle class_loader1,
2432 Handle class_loader2,
2433 Thread* THREAD) {
2434 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2435 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2436
2437 Symbol* constraint_name = NULL;
2438
2439 if (!Signature::is_array(class_name)) {
2440 constraint_name = class_name;
2441 } else {
2442 // For array classes, their Klass*s are not kept in the
2443 // constraint table. The element classes are.
2444 SignatureStream ss(class_name, false);
2445 ss.skip_array_prefix(); // skip all '['s
2446 if (!ss.has_envelope()) {
2447 return true; // primitive types always pass
2448 }
2449 constraint_name = ss.as_symbol();
2450 // Increment refcount to keep constraint_name alive after
2451 // SignatureStream is destructed. It will be decremented below
2452 // before returning.
2453 constraint_name->increment_refcount();
2454 }
2455
2456 Dictionary* dictionary1 = loader_data1->dictionary();
2457 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2458
2459 Dictionary* dictionary2 = loader_data2->dictionary();
2460 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2461
2462 {
2463 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2464 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2465 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2466 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2467 klass2, class_loader2);
2468 #if INCLUDE_CDS
2469 if (Arguments::is_dumping_archive() && klass_being_linked != NULL &&
2470 !klass_being_linked->is_shared()) {
2471 SystemDictionaryShared::record_linking_constraint(constraint_name,
2472 InstanceKlass::cast(klass_being_linked),
2473 class_loader1, class_loader2, THREAD);
2474 }
2475 #endif // INCLUDE_CDS
2476 if (Signature::is_array(class_name)) {
2477 constraint_name->decrement_refcount();
2478 }
2479 return result;
2480 }
2481 }
2482
2483 // Add entry to resolution error table to record the error when the first
2484 // attempt to resolve a reference to a class has failed.
2485 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2486 Symbol* error, Symbol* message) {
2487 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2488 int index = resolution_errors()->hash_to_index(hash);
2489 {
2490 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2491 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2492 }
2493 }
2494
2495 // Delete a resolution error for RedefineClasses for a constant pool is going away
2496 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2497 resolution_errors()->delete_entry(pool);
2498 }
2499
2500 // Lookup resolution error table. Returns error if found, otherwise NULL.
2501 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2502 Symbol** message) {
2503 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2504 int index = resolution_errors()->hash_to_index(hash);
2505 {
2506 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2507 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2508 if (entry != NULL) {
2509 *message = entry->message();
2510 return entry->error();
2511 } else {
2512 return NULL;
2513 }
2514 }
2515 }
2516
2517 // Add an entry to resolution error table to record an error in resolving or
2518 // validating a nest host. This is used to construct informative error
2519 // messages when IllegalAccessError's occur. If an entry already exists it will
2520 // be updated with the nest host error message.
2521 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
2522 int which,
2523 const char* message) {
2524 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2525 int index = resolution_errors()->hash_to_index(hash);
2526 {
2527 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2528 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2529 if (entry != NULL) {
2530 assert(entry->nest_host_error() == NULL, "Nest host error message already set!");
2531 entry->set_nest_host_error(message);
2532 } else {
2533 resolution_errors()->add_entry(index, hash, pool, which, message);
2534 }
2535 }
2536 }
2537
2538 // Lookup any nest host error
2539 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
2540 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2541 int index = resolution_errors()->hash_to_index(hash);
2542 {
2543 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2544 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2545 if (entry != NULL) {
2546 return entry->nest_host_error();
2547 } else {
2548 return NULL;
2549 }
2550 }
2551 }
2552
2553
2554 // Signature constraints ensure that callers and callees agree about
2555 // the meaning of type names in their signatures. This routine is the
2556 // intake for constraints. It collects them from several places:
2557 //
2558 // * LinkResolver::resolve_method (if check_access is true) requires
2559 // that the resolving class (the caller) and the defining class of
2560 // the resolved method (the callee) agree on each type in the
2561 // method's signature.
2562 //
2563 // * LinkResolver::resolve_interface_method performs exactly the same
2564 // checks.
2565 //
2566 // * LinkResolver::resolve_field requires that the constant pool
2567 // attempting to link to a field agree with the field's defining
2568 // class about the type of the field signature.
2569 //
2570 // * klassVtable::initialize_vtable requires that, when a class
2571 // overrides a vtable entry allocated by a superclass, that the
2572 // overriding method (i.e., the callee) agree with the superclass
2573 // on each type in the method's signature.
2574 //
2575 // * klassItable::initialize_itable requires that, when a class fills
2576 // in its itables, for each non-abstract method installed in an
2577 // itable, the method (i.e., the callee) agree with the interface
2578 // on each type in the method's signature.
2579 //
2580 // All those methods have a boolean (check_access, checkconstraints)
2581 // which turns off the checks. This is used from specialized contexts
2582 // such as bootstrapping, dumping, and debugging.
2583 //
2584 // No direct constraint is placed between the class and its
2585 // supertypes. Constraints are only placed along linked relations
2586 // between callers and callees. When a method overrides or implements
2587 // an abstract method in a supertype (superclass or interface), the
2588 // constraints are placed as if the supertype were the caller to the
2589 // overriding method. (This works well, since callers to the
2590 // supertype have already established agreement between themselves and
2591 // the supertype.) As a result of all this, a class can disagree with
2592 // its supertype about the meaning of a type name, as long as that
2593 // class neither calls a relevant method of the supertype, nor is
2594 // called (perhaps via an override) from the supertype.
2595 //
2596 //
2597 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
2598 //
2599 // Make sure all class components (including arrays) in the given
2600 // signature will be resolved to the same class in both loaders.
2601 // Returns the name of the type that failed a loader constraint check, or
2602 // NULL if no constraint failed. No exception except OOME is thrown.
2603 // Arrays are not added to the loader constraint table, their elements are.
2604 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2605 Klass* klass_being_linked,
2606 Handle loader1, Handle loader2,
2607 bool is_method, TRAPS) {
2608 // Nothing to do if loaders are the same.
2609 if (loader1() == loader2()) {
2610 return NULL;
2611 }
2612
2613 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2614 if (ss.is_reference()) {
2615 Symbol* sig = ss.as_symbol();
2616 // Note: In the future, if template-like types can take
2617 // arguments, we will want to recognize them and dig out class
2618 // names hiding inside the argument lists.
2619 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2, THREAD)) {
2620 return sig;
2621 }
2622 }
2623 }
2624 return NULL;
2625 }
2626
2627 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2628 Symbol* signature,
2629 TRAPS) {
2630 methodHandle empty;
2631 assert(MethodHandles::is_signature_polymorphic(iid) &&
2632 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2633 iid != vmIntrinsics::_invokeGeneric,
2634 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2635
2636 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2637 int index = invoke_method_table()->hash_to_index(hash);
2638 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2639 methodHandle m;
2640 if (spe == NULL || spe->method() == NULL) {
2641 spe = NULL;
2642 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2643 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2644 if (!Arguments::is_interpreter_only()) {
2645 // Generate a compiled form of the MH intrinsic.
2646 AdapterHandlerLibrary::create_native_wrapper(m);
2647 // Check if have the compiled code.
2648 if (!m->has_compiled_code()) {
2649 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2650 "Out of space in CodeCache for method handle intrinsic");
2651 }
2652 }
2653 // Now grab the lock. We might have to throw away the new method,
2654 // if a racing thread has managed to install one at the same time.
2655 {
2656 MutexLocker ml(THREAD, SystemDictionary_lock);
2657 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2658 if (spe == NULL)
2659 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2660 if (spe->method() == NULL)
2661 spe->set_method(m());
2662 }
2663 }
2664
2665 assert(spe != NULL && spe->method() != NULL, "");
2666 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2667 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2668 "MH intrinsic invariant");
2669 return spe->method();
2670 }
2671
2672 // Helper for unpacking the return value from linkMethod and linkCallSite.
2673 static Method* unpack_method_and_appendix(Handle mname,
2674 Klass* accessing_klass,
2675 objArrayHandle appendix_box,
2676 Handle* appendix_result,
2677 TRAPS) {
2678 if (mname.not_null()) {
2679 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2680 if (m != NULL) {
2681 oop appendix = appendix_box->obj_at(0);
2682 LogTarget(Info, methodhandles) lt;
2683 if (lt.develop_is_enabled()) {
2684 ResourceMark rm(THREAD);
2685 LogStream ls(lt);
2686 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2687 m->print_on(&ls);
2688 if (appendix != NULL) { ls.print("appendix = "); appendix->print_on(&ls); }
2689 ls.cr();
2690 }
2691
2692 (*appendix_result) = Handle(THREAD, appendix);
2693 // the target is stored in the cpCache and if a reference to this
2694 // MemberName is dropped we need a way to make sure the
2695 // class_loader containing this method is kept alive.
2696 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2697 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2698 this_key->record_dependency(m->method_holder());
2699 return mh();
2700 }
2701 }
2702 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2703 }
2704
2705 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2706 Symbol* name,
2707 Symbol* signature,
2708 Klass* accessing_klass,
2709 Handle *appendix_result,
2710 TRAPS) {
2711 assert(THREAD->can_call_java() ,"");
2712 Handle method_type =
2713 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2714
2715 int ref_kind = JVM_REF_invokeVirtual;
2716 oop name_oop = StringTable::intern(name, CHECK_NULL);
2717 Handle name_str (THREAD, name_oop);
2718 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2719 assert(appendix_box->obj_at(0) == NULL, "");
2720
2721 // This should not happen. JDK code should take care of that.
2722 if (accessing_klass == NULL || method_type.is_null()) {
2723 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2724 }
2725
2726 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2727 JavaCallArguments args;
2728 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2729 args.push_int(ref_kind);
2730 args.push_oop(Handle(THREAD, klass->java_mirror()));
2731 args.push_oop(name_str);
2732 args.push_oop(method_type);
2733 args.push_oop(appendix_box);
2734 JavaValue result(T_OBJECT);
2735 JavaCalls::call_static(&result,
2736 SystemDictionary::MethodHandleNatives_klass(),
2737 vmSymbols::linkMethod_name(),
2738 vmSymbols::linkMethod_signature(),
2739 &args, CHECK_NULL);
2740 Handle mname(THREAD, (oop) result.get_jobject());
2741 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2742 }
2743
2744 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2745 // We must ensure that all class loaders everywhere will reach this class, for any client.
2746 // This is a safe bet for public classes in java.lang, such as Object and String.
2747 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2748 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2749 static bool is_always_visible_class(oop mirror) {
2750 Klass* klass = java_lang_Class::as_Klass(mirror);
2751 if (klass->is_objArray_klass()) {
2752 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2753 }
2754 if (klass->is_typeArray_klass()) {
2755 return true; // primitive array
2756 }
2757 assert(klass->is_instance_klass(), "%s", klass->external_name());
2758 return klass->is_public() &&
2759 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2760 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2761 }
2762
2763 // Find or construct the Java mirror (java.lang.Class instance) for
2764 // the given field type signature, as interpreted relative to the
2765 // given class loader. Handles primitives, void, references, arrays,
2766 // and all other reflectable types, except method types.
2767 // N.B. Code in reflection should use this entry point.
2768 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2769 Klass* accessing_klass,
2770 Handle class_loader,
2771 Handle protection_domain,
2772 SignatureStream::FailureMode failure_mode,
2773 TRAPS) {
2774 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2775 "one or the other, or perhaps neither");
2776
2777 // What we have here must be a valid field descriptor,
2778 // and all valid field descriptors are supported.
2779 // Produce the same java.lang.Class that reflection reports.
2780 if (accessing_klass != NULL) {
2781 class_loader = Handle(THREAD, accessing_klass->class_loader());
2782 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2783 }
2784 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2785 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2786 if (mirror_oop == NULL) {
2787 return Handle(); // report failure this way
2788 }
2789 Handle mirror(THREAD, mirror_oop);
2790
2791 if (accessing_klass != NULL) {
2792 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2793 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2794 if (sel_klass != NULL) {
2795 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2796 }
2797 }
2798 return mirror;
2799 }
2800
2801
2802 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2803 // signature, as interpreted relative to the given class loader.
2804 // Because of class loader constraints, all method handle usage must be
2805 // consistent with this loader.
2806 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2807 Klass* accessing_klass,
2808 TRAPS) {
2809 Handle empty;
2810 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2811 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2812 int index = invoke_method_table()->hash_to_index(hash);
2813 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2814 if (spe != NULL && spe->method_type() != NULL) {
2815 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2816 return Handle(THREAD, spe->method_type());
2817 } else if (!THREAD->can_call_java()) {
2818 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2819 return Handle(); // do not attempt from within compiler, unless it was cached
2820 }
2821
2822 Handle class_loader, protection_domain;
2823 if (accessing_klass != NULL) {
2824 class_loader = Handle(THREAD, accessing_klass->class_loader());
2825 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2826 }
2827 bool can_be_cached = true;
2828 int npts = ArgumentCount(signature).size();
2829 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2830 int arg = 0;
2831 Handle rt; // the return type from the signature
2832 ResourceMark rm(THREAD);
2833 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2834 oop mirror = NULL;
2835 if (can_be_cached) {
2836 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2837 mirror = ss.as_java_mirror(Handle(), Handle(),
2838 SignatureStream::ReturnNull, CHECK_(empty));
2839 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2840 // Fall back to accessing_klass context.
2841 can_be_cached = false;
2842 }
2843 }
2844 if (!can_be_cached) {
2845 // Resolve, throwing a real error if it doesn't work.
2846 mirror = ss.as_java_mirror(class_loader, protection_domain,
2847 SignatureStream::NCDFError, CHECK_(empty));
2848 }
2849 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2850 if (ss.at_return_type())
2851 rt = Handle(THREAD, mirror);
2852 else
2853 pts->obj_at_put(arg++, mirror);
2854
2855 // Check accessibility.
2856 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2857 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2858 mirror = NULL; // safety
2859 // Emulate ConstantPool::verify_constant_pool_resolve.
2860 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2861 }
2862 }
2863 assert(arg == npts, "");
2864
2865 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2866 JavaCallArguments args(Handle(THREAD, rt()));
2867 args.push_oop(pts);
2868 JavaValue result(T_OBJECT);
2869 JavaCalls::call_static(&result,
2870 SystemDictionary::MethodHandleNatives_klass(),
2871 vmSymbols::findMethodHandleType_name(),
2872 vmSymbols::findMethodHandleType_signature(),
2873 &args, CHECK_(empty));
2874 Handle method_type(THREAD, (oop) result.get_jobject());
2875
2876 if (can_be_cached) {
2877 // We can cache this MethodType inside the JVM.
2878 MutexLocker ml(THREAD, SystemDictionary_lock);
2879 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2880 if (spe == NULL)
2881 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2882 if (spe->method_type() == NULL) {
2883 spe->set_method_type(method_type());
2884 }
2885 }
2886
2887 // report back to the caller with the MethodType
2888 return method_type;
2889 }
2890
2891 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2892 Klass* accessing_klass,
2893 TRAPS) {
2894 Handle empty;
2895 ResourceMark rm(THREAD);
2896 SignatureStream ss(signature, /*is_method=*/ false);
2897 if (!ss.is_done()) {
2898 Handle class_loader, protection_domain;
2899 if (accessing_klass != NULL) {
2900 class_loader = Handle(THREAD, accessing_klass->class_loader());
2901 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2902 }
2903 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2904 ss.next();
2905 if (ss.is_done()) {
2906 return Handle(THREAD, mirror);
2907 }
2908 }
2909 return empty;
2910 }
2911
2912 // Ask Java code to find or construct a method handle constant.
2913 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2914 int ref_kind, //e.g., JVM_REF_invokeVirtual
2915 Klass* callee,
2916 Symbol* name,
2917 Symbol* signature,
2918 TRAPS) {
2919 Handle empty;
2920 if (caller == NULL) {
2921 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2922 }
2923 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2924 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2925
2926 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2927 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2928 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2929 java_lang_invoke_MemberName::set_name (mname(), name_str());
2930 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2931 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2932
2933 if (ref_kind == JVM_REF_invokeVirtual &&
2934 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2935 // Skip resolution for public signature polymorphic methods such as
2936 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2937 // They require appendix argument which MemberName resolution doesn't handle.
2938 // There's special logic on JDK side to handle them
2939 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2940 } else {
2941 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2942 }
2943
2944 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2945 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2946
2947 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2948 JavaCallArguments args;
2949 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2950 args.push_int(ref_kind);
2951 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2952 args.push_oop(name_str);
2953 args.push_oop(type);
2954 JavaValue result(T_OBJECT);
2955 JavaCalls::call_static(&result,
2956 SystemDictionary::MethodHandleNatives_klass(),
2957 vmSymbols::linkMethodHandleConstant_name(),
2958 vmSymbols::linkMethodHandleConstant_signature(),
2959 &args, CHECK_(empty));
2960 return Handle(THREAD, (oop) result.get_jobject());
2961 }
2962
2963 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2964 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2965 // with linkage results being stored back into the bootstrap specifier.
2966 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2967 // Resolve the bootstrap specifier, its name, type, and static arguments
2968 bootstrap_specifier.resolve_bsm(CHECK);
2969
2970 // This should not happen. JDK code should take care of that.
2971 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2972 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2973 }
2974
2975 bool is_indy = bootstrap_specifier.is_method_call();
2976 objArrayHandle appendix_box;
2977 if (is_indy) {
2978 // Some method calls may require an appendix argument. Arrange to receive it.
2979 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2980 assert(appendix_box->obj_at(0) == NULL, "");
2981 }
2982
2983 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2984 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2985 JavaCallArguments args;
2986 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2987 args.push_int(bootstrap_specifier.bss_index());
2988 args.push_oop(bootstrap_specifier.bsm());
2989 args.push_oop(bootstrap_specifier.name_arg());
2990 args.push_oop(bootstrap_specifier.type_arg());
2991 args.push_oop(bootstrap_specifier.arg_values());
2992 if (is_indy) {
2993 args.push_oop(appendix_box);
2994 }
2995 JavaValue result(T_OBJECT);
2996 JavaCalls::call_static(&result,
2997 SystemDictionary::MethodHandleNatives_klass(),
2998 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2999 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
3000 &args, CHECK);
3001
3002 Handle value(THREAD, (oop) result.get_jobject());
3003 if (is_indy) {
3004 Handle appendix;
3005 Method* method = unpack_method_and_appendix(value,
3006 bootstrap_specifier.caller(),
3007 appendix_box,
3008 &appendix, CHECK);
3009 methodHandle mh(THREAD, method);
3010 bootstrap_specifier.set_resolved_method(mh, appendix);
3011 } else {
3012 bootstrap_specifier.set_resolved_value(value);
3013 }
3014
3015 // sanity check
3016 assert(bootstrap_specifier.is_resolved() ||
3017 (bootstrap_specifier.is_method_call() &&
3018 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
3019 }
3020
3021 // Protection domain cache table handling
3022
3023 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
3024 return _pd_cache_table->get(protection_domain);
3025 }
3026
3027 // ----------------------------------------------------------------------------
3028
3029 void SystemDictionary::print_on(outputStream *st) {
3030 CDS_ONLY(SystemDictionaryShared::print_on(st));
3031 GCMutexLocker mu(SystemDictionary_lock);
3032
3033 ClassLoaderDataGraph::print_dictionary(st);
3034
3035 // Placeholders
3036 placeholders()->print_on(st);
3037 st->cr();
3038
3039 // loader constraints - print under SD_lock
3040 constraints()->print_on(st);
3041 st->cr();
3042
3043 _pd_cache_table->print_on(st);
3044 st->cr();
3045 }
3046
3047 void SystemDictionary::print() { print_on(tty); }
3048
3049 void SystemDictionary::verify() {
3050 guarantee(constraints() != NULL,
3051 "Verify of loader constraints failed");
3052 guarantee(placeholders()->number_of_entries() >= 0,
3053 "Verify of placeholders failed");
3054
3055 GCMutexLocker mu(SystemDictionary_lock);
3056
3057 // Verify dictionary
3058 ClassLoaderDataGraph::verify_dictionary();
3059
3060 placeholders()->verify();
3061
3062 // Verify constraint table
3063 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3064 constraints()->verify(placeholders());
3065
3066 _pd_cache_table->verify();
3067 }
3068
3069 void SystemDictionary::dump(outputStream *st, bool verbose) {
3070 assert_locked_or_safepoint(SystemDictionary_lock);
3071 if (verbose) {
3072 print_on(st);
3073 } else {
3074 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
3075 ClassLoaderDataGraph::print_table_statistics(st);
3076 placeholders()->print_table_statistics(st, "Placeholder Table");
3077 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3078 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
3079 }
3080 }
3081
3082 TableStatistics SystemDictionary::placeholders_statistics() {
3083 MutexLocker ml(SystemDictionary_lock);
3084 return placeholders()->statistics_calculate();
3085 }
3086
3087 TableStatistics SystemDictionary::loader_constraints_statistics() {
3088 MutexLocker ml(SystemDictionary_lock);
3089 return constraints()->statistics_calculate();
3090 }
3091
3092 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
3093 MutexLocker ml(SystemDictionary_lock);
3094 return pd_cache_table()->statistics_calculate();
3095 }
3096
3097 // Utility for dumping dictionaries.
3098 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3099 DCmdWithParser(output, heap),
3100 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3101 "BOOLEAN", false, "false") {
3102 _dcmdparser.add_dcmd_option(&_verbose);
3103 }
3104
3105 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3106 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3107 _verbose.value());
3108 VMThread::execute(&dumper);
3109 }
3110
3111 int SystemDictionaryDCmd::num_arguments() {
3112 ResourceMark rm;
3113 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3114 if (dcmd != NULL) {
3115 DCmdMark mark(dcmd);
3116 return dcmd->_dcmdparser.num_arguments();
3117 } else {
3118 return 0;
3119 }
3120 }