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/classLoaderDataShared.hpp"
34 #include "classfile/classLoaderExt.hpp"
35 #include "classfile/dictionary.hpp"
36 #include "classfile/javaClasses.inline.hpp"
37 #include "classfile/klassFactory.hpp"
38 #include "classfile/loaderConstraints.hpp"
39 #include "classfile/packageEntry.hpp"
40 #include "classfile/placeholders.hpp"
41 #include "classfile/protectionDomainCache.hpp"
42 #include "classfile/resolutionErrors.hpp"
43 #include "classfile/stringTable.hpp"
44 #include "classfile/symbolTable.hpp"
45 #include "classfile/systemDictionary.hpp"
46 #include "classfile/vmSymbols.hpp"
47 #include "code/codeCache.hpp"
48 #include "compiler/compileBroker.hpp"
49 #include "gc/shared/gcTraceTime.inline.hpp"
50 #include "interpreter/bytecodeStream.hpp"
51 #include "interpreter/interpreter.hpp"
52 #include "jfr/jfrEvents.hpp"
53 #include "logging/log.hpp"
54 #include "logging/logStream.hpp"
55 #include "memory/filemap.hpp"
56 #include "memory/heapShared.hpp"
57 #include "memory/metaspaceClosure.hpp"
58 #include "memory/oopFactory.hpp"
59 #include "memory/resourceArea.hpp"
60 #include "memory/universe.hpp"
61 #include "oops/access.inline.hpp"
62 #include "oops/instanceKlass.hpp"
63 #include "oops/instanceRefKlass.hpp"
64 #include "oops/klass.inline.hpp"
65 #include "oops/method.inline.hpp"
66 #include "oops/methodData.hpp"
67 #include "oops/objArrayKlass.hpp"
68 #include "oops/objArrayOop.inline.hpp"
69 #include "oops/oop.inline.hpp"
70 #include "oops/oopHandle.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #include "utilities/utf8.hpp"
88 #if INCLUDE_CDS
89 #include "classfile/systemDictionaryShared.hpp"
90 #endif
91 #if INCLUDE_JFR
92 #include "jfr/jfr.hpp"
93 #endif
94
95 PlaceholderTable* SystemDictionary::_placeholders = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106
107 OopHandle SystemDictionary::_system_loader_lock_obj;
108 OopHandle SystemDictionary::_java_system_loader;
109 OopHandle SystemDictionary::_java_platform_loader;
110
111 // Default ProtectionDomainCacheSize value
112
113 const int defaultProtectionDomainCacheSize = 1009;
114
115 ClassLoadInfo::ClassLoadInfo() {
116 _protection_domain = Handle();
117 _unsafe_anonymous_host = NULL;
118 _cp_patches = NULL;
119 _class_hidden_info._dynamic_nest_host = NULL;
120 _class_hidden_info._class_data = Handle();
121 _is_hidden = false;
122 _is_strong_hidden = false;
123 _can_access_vm_annotations = false;
124 }
125
126 ClassLoadInfo::ClassLoadInfo(Handle protection_domain) {
127 _protection_domain = protection_domain;
128 _unsafe_anonymous_host = NULL;
129 _cp_patches = NULL;
130 _class_hidden_info._dynamic_nest_host = NULL;
131 _class_hidden_info._class_data = Handle();
132 _is_hidden = false;
133 _is_strong_hidden = false;
134 _can_access_vm_annotations = false;
135 }
136
137 ClassLoadInfo::ClassLoadInfo(Handle protection_domain,
138 const InstanceKlass* unsafe_anonymous_host,
139 GrowableArray<Handle>* cp_patches,
140 InstanceKlass* dynamic_nest_host,
141 Handle class_data,
142 bool is_hidden,
143 bool is_strong_hidden,
144 bool can_access_vm_annotations) {
145 _protection_domain = protection_domain;
146 _unsafe_anonymous_host = unsafe_anonymous_host;
147 _cp_patches = cp_patches;
148 _class_hidden_info._dynamic_nest_host = dynamic_nest_host;
149 _class_hidden_info._class_data = class_data;
150 _is_hidden = is_hidden;
151 _is_strong_hidden = is_strong_hidden;
152 _can_access_vm_annotations = can_access_vm_annotations;
153 }
154
155 // ----------------------------------------------------------------------------
156 // Java-level SystemLoader and PlatformLoader
157
158 oop SystemDictionary::system_loader_lock() {
159 return _system_loader_lock_obj.resolve();
160 }
161
162 oop SystemDictionary::java_system_loader() {
163 return _java_system_loader.resolve();
164 }
165
166 oop SystemDictionary::java_platform_loader() {
167 return _java_platform_loader.resolve();
168 }
169
170 void SystemDictionary::compute_java_loaders(TRAPS) {
171 JavaValue result(T_OBJECT);
172 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
173 JavaCalls::call_static(&result,
174 class_loader_klass,
175 vmSymbols::getSystemClassLoader_name(),
176 vmSymbols::void_classloader_signature(),
177 CHECK);
178
179 _java_system_loader = OopHandle(Universe::vm_global(), (oop)result.get_jobject());
180
181 JavaCalls::call_static(&result,
182 class_loader_klass,
183 vmSymbols::getPlatformClassLoader_name(),
184 vmSymbols::void_classloader_signature(),
185 CHECK);
186
187 _java_platform_loader = OopHandle(Universe::vm_global(), (oop)result.get_jobject());
188 }
189
190 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
191 if (create_mirror_cld) {
192 // Add a new class loader data to the graph.
193 return ClassLoaderDataGraph::add(class_loader, true);
194 } else {
195 return (class_loader() == NULL) ? ClassLoaderData::the_null_class_loader_data() :
196 ClassLoaderDataGraph::find_or_create(class_loader);
197 }
198 }
199
200 // ----------------------------------------------------------------------------
201 // Parallel class loading check
202
203 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
204 if (class_loader.is_null()) return true;
205 if (AlwaysLockClassLoader) return false;
206 return java_lang_ClassLoader::parallelCapable(class_loader());
207 }
208 // ----------------------------------------------------------------------------
209 // ParallelDefineClass flag does not apply to bootclass loader
210 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
211 if (class_loader.is_null()) return false;
212 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
213 return true;
214 }
215 return false;
216 }
217
218 // Returns true if the passed class loader is the builtin application class loader
219 // or a custom system class loader. A customer system class loader can be
220 // specified via -Djava.system.class.loader.
221 bool SystemDictionary::is_system_class_loader(oop class_loader) {
222 if (class_loader == NULL) {
223 return false;
224 }
225 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
226 class_loader == _java_system_loader.peek());
227 }
228
229 // Returns true if the passed class loader is the platform class loader.
230 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
231 if (class_loader == NULL) {
232 return false;
233 }
234 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
235 }
236
237 // ----------------------------------------------------------------------------
238 // Resolving of classes
239
240 Symbol* SystemDictionary::class_name_symbol(const char* name, Symbol* exception, TRAPS) {
241 if (name == NULL) {
242 THROW_MSG_0(exception, "No class name given");
243 }
244 if ((int)strlen(name) > Symbol::max_length()) {
245 // It's impossible to create this class; the name cannot fit
246 // into the constant pool.
247 Exceptions::fthrow(THREAD_AND_LOCATION, exception,
248 "Class name exceeds maximum length of %d: %s",
249 Symbol::max_length(),
250 name);
251 return NULL;
252 }
253 // Callers should ensure that the name is never an illegal UTF8 string.
254 assert(UTF8::is_legal_utf8((const unsigned char*)name, (int)strlen(name), false),
255 "Class name is not a valid utf8 string.");
256
257 // Make a new symbol for the class name.
258 return SymbolTable::new_symbol(name);
259 }
260
261 // Forwards to resolve_or_null
262
263 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
264 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
265 if (HAS_PENDING_EXCEPTION || klass == NULL) {
266 // can return a null klass
267 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
268 }
269 return klass;
270 }
271
272 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
273 bool throw_error,
274 Klass* klass, TRAPS) {
275 if (HAS_PENDING_EXCEPTION) {
276 // If we have a pending exception we forward it to the caller, unless throw_error is true,
277 // in which case we have to check whether the pending exception is a ClassNotFoundException,
278 // and if so convert it to a NoClassDefFoundError
279 // And chain the original ClassNotFoundException
280 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
281 ResourceMark rm(THREAD);
282 assert(klass == NULL, "Should not have result with exception pending");
283 Handle e(THREAD, PENDING_EXCEPTION);
284 CLEAR_PENDING_EXCEPTION;
285 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
286 } else {
287 return NULL;
288 }
289 }
290 // Class not found, throw appropriate error or exception depending on value of throw_error
291 if (klass == NULL) {
292 ResourceMark rm(THREAD);
293 if (throw_error) {
294 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
295 } else {
296 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
297 }
298 }
299 return klass;
300 }
301
302
303 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
304 bool throw_error, TRAPS)
305 {
306 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
307 }
308
309
310 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
311
312 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
313 if (Signature::is_array(class_name)) {
314 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
315 } else {
316 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
317 }
318 }
319
320 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
321 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
322 Handle class_loader,
323 Handle protection_domain,
324 TRAPS) {
325 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
326 if (Signature::has_envelope(class_name)) {
327 ResourceMark rm(THREAD);
328 // Ignore wrapping L and ;.
329 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
330 class_name->utf8_length() - 2);
331 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
332 } else {
333 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
334 }
335 }
336
337 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
338 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
339 }
340
341 // Forwards to resolve_instance_class_or_null
342
343 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
344 Handle class_loader,
345 Handle protection_domain,
346 TRAPS) {
347 assert(Signature::is_array(class_name), "must be array");
348 ResourceMark rm(THREAD);
349 SignatureStream ss(class_name, false);
350 int ndims = ss.skip_array_prefix(); // skip all '['s
351 Klass* k = NULL;
352 BasicType t = ss.type();
353 if (ss.has_envelope()) {
354 Symbol* obj_class = ss.as_symbol();
355 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
356 class_loader,
357 protection_domain,
358 CHECK_NULL);
359 if (k != NULL) {
360 k = k->array_klass(ndims, CHECK_NULL);
361 }
362 } else {
363 k = Universe::typeArrayKlassObj(t);
364 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
365 }
366 return k;
367 }
368
369
370 // Must be called for any super-class or super-interface resolution
371 // during class definition to allow class circularity checking
372 // super-interface callers:
373 // parse_interfaces - for defineClass & jvmtiRedefineClasses
374 // super-class callers:
375 // ClassFileParser - for defineClass & jvmtiRedefineClasses
376 // load_shared_class - while loading a class from shared archive
377 // resolve_instance_class_or_null:
378 // via: handle_parallel_super_load
379 // when resolving a class that has an existing placeholder with
380 // a saved superclass [i.e. a defineClass is currently in progress]
381 // if another thread is trying to resolve the class, it must do
382 // super-class checks on its own thread to catch class circularity
383 // This last call is critical in class circularity checking for cases
384 // where classloading is delegated to different threads and the
385 // classloader lock is released.
386 // Take the case: Base->Super->Base
387 // 1. If thread T1 tries to do a defineClass of class Base
388 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
389 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
390 // so it tries to load Super
391 // 3. If we load the class internally, or user classloader uses same thread
392 // loadClassFromxxx or defineClass via parseClassFile Super ...
393 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
394 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
395 // 3.4 calls resolve_super_or_fail Base
396 // 3.5 finds T1,Base -> throws class circularity
397 //OR 4. If T2 tries to resolve Super via defineClass Super ...
398 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
399 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
400 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
401 // 4.4 finds T2, Super -> throws class circularity
402 // Must be called, even if superclass is null, since this is
403 // where the placeholder entry is created which claims this
404 // thread is loading this class/classloader.
405 // Be careful when modifying this code: once you have run
406 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
407 // you need to find_and_remove it before returning.
408 // So be careful to not exit with a CHECK_ macro betweeen these calls.
409 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
410 Symbol* super_name,
411 Handle class_loader,
412 Handle protection_domain,
413 bool is_superclass,
414 TRAPS) {
415 assert(!Signature::is_array(super_name), "invalid super class name");
416 #if INCLUDE_CDS
417 if (DumpSharedSpaces) {
418 // Special processing for handling UNREGISTERED shared classes.
419 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
420 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
421 if (k) {
422 return k;
423 }
424 }
425 #endif // INCLUDE_CDS
426
427 // Double-check, if child class is already loaded, just return super-class,interface
428 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
429 // dictionary.
430 // Make sure there's a placeholder for the *child* before resolving.
431 // Used as a claim that this thread is currently loading superclass/classloader
432 // Used here for ClassCircularity checks and also for heap verification
433 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
434 // Must check ClassCircularity before checking if super class is already loaded.
435 //
436 // We might not already have a placeholder if this child_name was
437 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
438 // the name of the class might not be known until the stream is actually
439 // parsed.
440 // Bugs 4643874, 4715493
441
442 ClassLoaderData* loader_data = class_loader_data(class_loader);
443 Dictionary* dictionary = loader_data->dictionary();
444 unsigned int d_hash = dictionary->compute_hash(child_name);
445 unsigned int p_hash = placeholders()->compute_hash(child_name);
446 int p_index = placeholders()->hash_to_index(p_hash);
447 // can't throw error holding a lock
448 bool child_already_loaded = false;
449 bool throw_circularity_error = false;
450 {
451 MutexLocker mu(THREAD, SystemDictionary_lock);
452 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
453 InstanceKlass* quicksuperk;
454 // to support // loading: if child done loading, just return superclass
455 // if super_name, & class_loader don't match:
456 // if initial define, SD update will give LinkageError
457 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
458 // so we don't throw an exception here.
459 // see: nsk redefclass014 & java.lang.instrument Instrument032
460 if ((childk != NULL ) && (is_superclass) &&
461 ((quicksuperk = childk->java_super()) != NULL) &&
462 ((quicksuperk->name() == super_name) &&
463 (quicksuperk->class_loader() == class_loader()))) {
464 return quicksuperk;
465 } else {
466 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
467 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
468 throw_circularity_error = true;
469 }
470 }
471 if (!throw_circularity_error) {
472 // Be careful not to exit resolve_super
473 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
474 }
475 }
476 if (throw_circularity_error) {
477 ResourceMark rm(THREAD);
478 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
479 }
480
481 // java.lang.Object should have been found above
482 assert(super_name != NULL, "null super class for resolving");
483 // Resolve the super class or interface, check results on return
484 InstanceKlass* superk =
485 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
486 class_loader,
487 protection_domain,
488 THREAD);
489
490 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
491 // It is no longer necessary to keep the placeholder table alive until update_dictionary
492 // or error. GC used to walk the placeholder table as strong roots.
493 // The instanceKlass is kept alive because the class loader is on the stack,
494 // which keeps the loader_data alive, as well as all instanceKlasses in
495 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
496 {
497 MutexLocker mu(THREAD, SystemDictionary_lock);
498 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
499 SystemDictionary_lock->notify_all();
500 }
501 if (HAS_PENDING_EXCEPTION || superk == NULL) {
502 // can null superk
503 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
504 assert(k == NULL || k == superk, "must be");
505 if (k == NULL) {
506 superk = NULL;
507 }
508 }
509
510 return superk;
511 }
512
513 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
514 Handle class_loader,
515 Handle protection_domain,
516 TRAPS) {
517 // Now we have to call back to java to check if the initating class has access
518 JavaValue result(T_VOID);
519 LogTarget(Debug, protectiondomain) lt;
520 if (lt.is_enabled()) {
521 ResourceMark rm(THREAD);
522 // Print out trace information
523 LogStream ls(lt);
524 ls.print_cr("Checking package access");
525 if (class_loader() != NULL) {
526 ls.print("class loader: ");
527 class_loader()->print_value_on(&ls);
528 } else {
529 ls.print_cr("class loader: NULL");
530 }
531 if (protection_domain() != NULL) {
532 ls.print(" protection domain: ");
533 protection_domain()->print_value_on(&ls);
534 } else {
535 ls.print_cr(" protection domain: NULL");
536 }
537 ls.print(" loading: "); klass->print_value_on(&ls);
538 ls.cr();
539 }
540
541 // This handle and the class_loader handle passed in keeps this class from
542 // being unloaded through several GC points.
543 // The class_loader handle passed in is the initiating loader.
544 Handle mirror(THREAD, klass->java_mirror());
545
546 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
547 JavaCalls::call_special(&result,
548 class_loader,
549 system_loader,
550 vmSymbols::checkPackageAccess_name(),
551 vmSymbols::class_protectiondomain_signature(),
552 mirror,
553 protection_domain,
554 THREAD);
555
556 if (HAS_PENDING_EXCEPTION) {
557 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
558 } else {
559 log_debug(protectiondomain)("granted");
560 }
561
562 if (HAS_PENDING_EXCEPTION) return;
563
564 // If no exception has been thrown, we have validated the protection domain
565 // Insert the protection domain of the initiating class into the set.
566 {
567 ClassLoaderData* loader_data = class_loader_data(class_loader);
568 Dictionary* dictionary = loader_data->dictionary();
569
570 Symbol* kn = klass->name();
571 unsigned int d_hash = dictionary->compute_hash(kn);
572
573 MutexLocker mu(THREAD, SystemDictionary_lock);
574 int d_index = dictionary->hash_to_index(d_hash);
575 dictionary->add_protection_domain(d_index, d_hash, klass,
576 protection_domain, THREAD);
577 }
578 }
579
580 // We only get here if this thread finds that another thread
581 // has already claimed the placeholder token for the current operation,
582 // but that other thread either never owned or gave up the
583 // object lock
584 // Waits on SystemDictionary_lock to indicate placeholder table updated
585 // On return, caller must recheck placeholder table state
586 //
587 // We only get here if
588 // 1) custom classLoader, i.e. not bootstrap classloader
589 // 2) custom classLoader has broken the class loader objectLock
590 // so another thread got here in parallel
591 //
592 // lockObject must be held.
593 // Complicated dance due to lock ordering:
594 // Must first release the classloader object lock to
595 // allow initial definer to complete the class definition
596 // and to avoid deadlock
597 // Reclaim classloader lock object with same original recursion count
598 // Must release SystemDictionary_lock after notify, since
599 // class loader lock must be claimed before SystemDictionary_lock
600 // to prevent deadlocks
601 //
602 // The notify allows applications that did an untimed wait() on
603 // the classloader object lock to not hang.
604 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
605 assert_lock_strong(SystemDictionary_lock);
606
607 bool calledholdinglock
608 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
609 assert(calledholdinglock,"must hold lock for notify");
610 assert((lockObject() != _system_loader_lock_obj.resolve() &&
611 !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
612 ObjectSynchronizer::notifyall(lockObject, THREAD);
613 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
614 SystemDictionary_lock->wait();
615 SystemDictionary_lock->unlock();
616 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
617 SystemDictionary_lock->lock();
618 }
619
620 // If the class in is in the placeholder table, class loading is in progress
621 // For cases where the application changes threads to load classes, it
622 // is critical to ClassCircularity detection that we try loading
623 // the superclass on the same thread internally, so we do parallel
624 // super class loading here.
625 // This also is critical in cases where the original thread gets stalled
626 // even in non-circularity situations.
627 // Note: must call resolve_super_or_fail even if null super -
628 // to force placeholder entry creation for this class for circularity detection
629 // Caller must check for pending exception
630 // Returns non-null Klass* if other thread has completed load
631 // and we are done,
632 // If return null Klass* and no pending exception, the caller must load the class
633 InstanceKlass* SystemDictionary::handle_parallel_super_load(
634 Symbol* name, Symbol* superclassname, Handle class_loader,
635 Handle protection_domain, Handle lockObject, TRAPS) {
636
637 ClassLoaderData* loader_data = class_loader_data(class_loader);
638 Dictionary* dictionary = loader_data->dictionary();
639 unsigned int d_hash = dictionary->compute_hash(name);
640 unsigned int p_hash = placeholders()->compute_hash(name);
641 int p_index = placeholders()->hash_to_index(p_hash);
642
643 // superk is not used, resolve_super called for circularity check only
644 // This code is reached in two situations. One if this thread
645 // is loading the same class twice (e.g. ClassCircularity, or
646 // java.lang.instrument).
647 // The second is if another thread started the resolve_super first
648 // and has not yet finished.
649 // In both cases the original caller will clean up the placeholder
650 // entry on error.
651 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
652 superclassname,
653 class_loader,
654 protection_domain,
655 true,
656 CHECK_NULL);
657
658 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
659 // Serial class loaders and bootstrap classloader do wait for superclass loads
660 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
661 MutexLocker mu(THREAD, SystemDictionary_lock);
662 // Check if classloading completed while we were loading superclass or waiting
663 return find_class(d_hash, name, dictionary);
664 }
665
666 // must loop to both handle other placeholder updates
667 // and spurious notifications
668 bool super_load_in_progress = true;
669 PlaceholderEntry* placeholder;
670 while (super_load_in_progress) {
671 MutexLocker mu(THREAD, SystemDictionary_lock);
672 // Check if classloading completed while we were loading superclass or waiting
673 InstanceKlass* check = find_class(d_hash, name, dictionary);
674 if (check != NULL) {
675 // Klass is already loaded, so just return it
676 return check;
677 } else {
678 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
679 if (placeholder && placeholder->super_load_in_progress() ){
680 // We only get here if the application has released the
681 // classloader lock when another thread was in the middle of loading a
682 // superclass/superinterface for this class, and now
683 // this thread is also trying to load this class.
684 // To minimize surprises, the first thread that started to
685 // load a class should be the one to complete the loading
686 // with the classfile it initially expected.
687 // This logic has the current thread wait once it has done
688 // all the superclass/superinterface loading it can, until
689 // the original thread completes the class loading or fails
690 // If it completes we will use the resulting InstanceKlass
691 // which we will find below in the systemDictionary.
692 // We also get here for parallel bootstrap classloader
693 if (class_loader.is_null()) {
694 SystemDictionary_lock->wait();
695 } else {
696 double_lock_wait(lockObject, THREAD);
697 }
698 } else {
699 // If not in SD and not in PH, other thread's load must have failed
700 super_load_in_progress = false;
701 }
702 }
703 }
704 return NULL;
705 }
706
707 void SystemDictionary::post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
708 assert(event != NULL, "invariant");
709 assert(k != NULL, "invariant");
710 assert(event->should_commit(), "invariant");
711 event->set_loadedClass(k);
712 event->set_definingClassLoader(k->class_loader_data());
713 event->set_initiatingClassLoader(init_cld);
714 event->commit();
715 }
716
717
718 // Be careful when modifying this code: once you have run
719 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
720 // you need to find_and_remove it before returning.
721 // So be careful to not exit with a CHECK_ macro betweeen these calls.
722 //
723 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
724 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
725 Handle class_loader,
726 Handle protection_domain,
727 TRAPS) {
728 assert(name != NULL && !Signature::is_array(name) &&
729 !Signature::has_envelope(name), "invalid class name");
730
731 EventClassLoad class_load_start_event;
732
733 HandleMark hm(THREAD);
734
735 // Fix for 4474172; see evaluation for more details
736 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
737 ClassLoaderData* loader_data = register_loader(class_loader);
738 Dictionary* dictionary = loader_data->dictionary();
739 unsigned int d_hash = dictionary->compute_hash(name);
740
741 // Do lookup to see if class already exist and the protection domain
742 // has the right access
743 // This call uses find which checks protection domain already matches
744 // All subsequent calls use find_class, and set has_loaded_class so that
745 // before we return a result we call out to java to check for valid protection domain
746 // to allow returning the Klass* and add it to the pd_set if it is valid
747 {
748 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
749 if (probe != NULL) return probe;
750 }
751
752 // Non-bootstrap class loaders will call out to class loader and
753 // define via jvm/jni_DefineClass which will acquire the
754 // class loader object lock to protect against multiple threads
755 // defining the class in parallel by accident.
756 // This lock must be acquired here so the waiter will find
757 // any successful result in the SystemDictionary and not attempt
758 // the define.
759 // ParallelCapable Classloaders and the bootstrap classloader
760 // do not acquire lock here.
761 bool DoObjectLock = true;
762 if (is_parallelCapable(class_loader)) {
763 DoObjectLock = false;
764 }
765
766 unsigned int p_hash = placeholders()->compute_hash(name);
767 int p_index = placeholders()->hash_to_index(p_hash);
768
769 // Class is not in SystemDictionary so we have to do loading.
770 // Make sure we are synchronized on the class loader before we proceed
771 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
772 check_loader_lock_contention(lockObject, THREAD);
773 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
774
775 // Check again (after locking) if class already exist in SystemDictionary
776 bool class_has_been_loaded = false;
777 bool super_load_in_progress = false;
778 bool havesupername = false;
779 InstanceKlass* k = NULL;
780 PlaceholderEntry* placeholder;
781 Symbol* superclassname = NULL;
782
783 assert(THREAD->can_call_java(),
784 "can not load classes with compiler thread: class=%s, classloader=%s",
785 name->as_C_string(),
786 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
787 {
788 MutexLocker mu(THREAD, SystemDictionary_lock);
789 InstanceKlass* check = find_class(d_hash, name, dictionary);
790 if (check != NULL) {
791 // InstanceKlass is already loaded, so just return it
792 class_has_been_loaded = true;
793 k = check;
794 } else {
795 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
796 if (placeholder && placeholder->super_load_in_progress()) {
797 super_load_in_progress = true;
798 if (placeholder->havesupername() == true) {
799 superclassname = placeholder->supername();
800 havesupername = true;
801 }
802 }
803 }
804 }
805
806 // If the class is in the placeholder table, class loading is in progress
807 if (super_load_in_progress && havesupername==true) {
808 k = handle_parallel_super_load(name,
809 superclassname,
810 class_loader,
811 protection_domain,
812 lockObject, THREAD);
813 if (HAS_PENDING_EXCEPTION) {
814 return NULL;
815 }
816 if (k != NULL) {
817 class_has_been_loaded = true;
818 }
819 }
820
821 bool throw_circularity_error = false;
822 if (!class_has_been_loaded) {
823 bool load_instance_added = false;
824
825 // add placeholder entry to record loading instance class
826 // Five cases:
827 // All cases need to prevent modifying bootclasssearchpath
828 // in parallel with a classload of same classname
829 // Redefineclasses uses existence of the placeholder for the duration
830 // of the class load to prevent concurrent redefinition of not completely
831 // defined classes.
832 // case 1. traditional classloaders that rely on the classloader object lock
833 // - no other need for LOAD_INSTANCE
834 // case 2. traditional classloaders that break the classloader object lock
835 // as a deadlock workaround. Detection of this case requires that
836 // this check is done while holding the classloader object lock,
837 // and that lock is still held when calling classloader's loadClass.
838 // For these classloaders, we ensure that the first requestor
839 // completes the load and other requestors wait for completion.
840 // case 3. Bootstrap classloader - don't own objectLocker
841 // This classloader supports parallelism at the classloader level,
842 // but only allows a single load of a class/classloader pair.
843 // No performance benefit and no deadlock issues.
844 // case 4. parallelCapable user level classloaders - without objectLocker
845 // Allow parallel classloading of a class/classloader pair
846
847 {
848 MutexLocker mu(THREAD, SystemDictionary_lock);
849 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
850 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
851 if (oldprobe) {
852 // only need check_seen_thread once, not on each loop
853 // 6341374 java/lang/Instrument with -Xcomp
854 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
855 throw_circularity_error = true;
856 } else {
857 // case 1: traditional: should never see load_in_progress.
858 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
859
860 // case 3: bootstrap classloader: prevent futile classloading,
861 // wait on first requestor
862 if (class_loader.is_null()) {
863 SystemDictionary_lock->wait();
864 } else {
865 // case 2: traditional with broken classloader lock. wait on first
866 // requestor.
867 double_lock_wait(lockObject, THREAD);
868 }
869 // Check if classloading completed while we were waiting
870 InstanceKlass* check = find_class(d_hash, name, dictionary);
871 if (check != NULL) {
872 // Klass is already loaded, so just return it
873 k = check;
874 class_has_been_loaded = true;
875 }
876 // check if other thread failed to load and cleaned up
877 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
878 }
879 }
880 }
881 }
882 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
883 // case 4: parallelCapable: allow competing threads to try
884 // LOAD_INSTANCE in parallel
885
886 if (!throw_circularity_error && !class_has_been_loaded) {
887 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
888 load_instance_added = true;
889 // For class loaders that do not acquire the classloader object lock,
890 // if they did not catch another thread holding LOAD_INSTANCE,
891 // need a check analogous to the acquire ObjectLocker/find_class
892 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
893 // one final check if the load has already completed
894 // class loaders holding the ObjectLock shouldn't find the class here
895 InstanceKlass* check = find_class(d_hash, name, dictionary);
896 if (check != NULL) {
897 // Klass is already loaded, so return it after checking/adding protection domain
898 k = check;
899 class_has_been_loaded = true;
900 }
901 }
902 }
903
904 // must throw error outside of owning lock
905 if (throw_circularity_error) {
906 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
907 ResourceMark rm(THREAD);
908 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
909 }
910
911 if (!class_has_been_loaded) {
912
913 // Do actual loading
914 k = load_instance_class(name, class_loader, THREAD);
915
916 // If everything was OK (no exceptions, no null return value), and
917 // class_loader is NOT the defining loader, do a little more bookkeeping.
918 if (!HAS_PENDING_EXCEPTION && k != NULL &&
919 k->class_loader() != class_loader()) {
920
921 check_constraints(d_hash, k, class_loader, false, THREAD);
922
923 // Need to check for a PENDING_EXCEPTION again; check_constraints
924 // can throw but we may have to remove entry from the placeholder table below.
925 if (!HAS_PENDING_EXCEPTION) {
926 // Record dependency for non-parent delegation.
927 // This recording keeps the defining class loader of the klass (k) found
928 // from being unloaded while the initiating class loader is loaded
929 // even if the reference to the defining class loader is dropped
930 // before references to the initiating class loader.
931 loader_data->record_dependency(k);
932
933 { // Grabbing the Compile_lock prevents systemDictionary updates
934 // during compilations.
935 MutexLocker mu(THREAD, Compile_lock);
936 update_dictionary(d_hash, p_index, p_hash,
937 k, class_loader, THREAD);
938 }
939
940 if (JvmtiExport::should_post_class_load()) {
941 Thread *thread = THREAD;
942 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
943 JvmtiExport::post_class_load((JavaThread *) thread, k);
944 }
945 }
946 }
947 } // load_instance_class
948
949 if (load_instance_added == true) {
950 // clean up placeholder entries for LOAD_INSTANCE success or error
951 // This brackets the SystemDictionary updates for both defining
952 // and initiating loaders
953 MutexLocker mu(THREAD, SystemDictionary_lock);
954 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
955 SystemDictionary_lock->notify_all();
956 }
957 }
958
959 if (HAS_PENDING_EXCEPTION || k == NULL) {
960 return NULL;
961 }
962 if (class_load_start_event.should_commit()) {
963 post_class_load_event(&class_load_start_event, k, loader_data);
964 }
965 #ifdef ASSERT
966 {
967 ClassLoaderData* loader_data = k->class_loader_data();
968 MutexLocker mu(THREAD, SystemDictionary_lock);
969 InstanceKlass* kk = find_class(name, loader_data);
970 assert(kk == k, "should be present in dictionary");
971 }
972 #endif
973
974 // return if the protection domain in NULL
975 if (protection_domain() == NULL) return k;
976
977 // Check the protection domain has the right access
978 if (dictionary->is_valid_protection_domain(d_hash, name,
979 protection_domain)) {
980 return k;
981 }
982
983 // Verify protection domain. If it fails an exception is thrown
984 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
985
986 return k;
987 }
988
989
990 // This routine does not lock the system dictionary.
991 //
992 // Since readers don't hold a lock, we must make sure that system
993 // dictionary entries are only removed at a safepoint (when only one
994 // thread is running), and are added to in a safe way (all links must
995 // be updated in an MT-safe manner).
996 //
997 // Callers should be aware that an entry could be added just after
998 // _dictionary->bucket(index) is read here, so the caller will not see
999 // the new entry.
1000
1001 Klass* SystemDictionary::find(Symbol* class_name,
1002 Handle class_loader,
1003 Handle protection_domain,
1004 TRAPS) {
1005
1006 // The result of this call should be consistent with the result
1007 // of the call to resolve_instance_class_or_null().
1008 // See evaluation 6790209 and 4474172 for more details.
1009 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
1010 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
1011
1012 if (loader_data == NULL) {
1013 // If the ClassLoaderData has not been setup,
1014 // then the class loader has no entries in the dictionary.
1015 return NULL;
1016 }
1017
1018 Dictionary* dictionary = loader_data->dictionary();
1019 unsigned int d_hash = dictionary->compute_hash(class_name);
1020 return dictionary->find(d_hash, class_name,
1021 protection_domain);
1022 }
1023
1024
1025 // Look for a loaded instance or array klass by name. Do not do any loading.
1026 // return NULL in case of error.
1027 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
1028 Handle class_loader,
1029 Handle protection_domain,
1030 TRAPS) {
1031 Klass* k = NULL;
1032 assert(class_name != NULL, "class name must be non NULL");
1033
1034 if (Signature::is_array(class_name)) {
1035 // The name refers to an array. Parse the name.
1036 // dimension and object_key in FieldArrayInfo are assigned as a
1037 // side-effect of this call
1038 SignatureStream ss(class_name, false);
1039 int ndims = ss.skip_array_prefix(); // skip all '['s
1040 BasicType t = ss.type();
1041 if (t != T_OBJECT) {
1042 k = Universe::typeArrayKlassObj(t);
1043 } else {
1044 k = SystemDictionary::find(ss.as_symbol(), class_loader, protection_domain, THREAD);
1045 }
1046 if (k != NULL) {
1047 k = k->array_klass_or_null(ndims);
1048 }
1049 } else {
1050 k = find(class_name, class_loader, protection_domain, THREAD);
1051 }
1052 return k;
1053 }
1054
1055 // Note: this method is much like resolve_from_stream, but
1056 // does not publish the classes via the SystemDictionary.
1057 // Handles Lookup.defineClass hidden, unsafe_DefineAnonymousClass
1058 // and redefineclasses. RedefinedClasses do not add to the class hierarchy.
1059 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1060 Handle class_loader,
1061 ClassFileStream* st,
1062 const ClassLoadInfo& cl_info,
1063 TRAPS) {
1064
1065 EventClassLoad class_load_start_event;
1066 ClassLoaderData* loader_data;
1067 bool is_unsafe_anon_class = cl_info.unsafe_anonymous_host() != NULL;
1068
1069 // - for unsafe anonymous class: create a new CLD whith a class holder that uses
1070 // the same class loader as the unsafe_anonymous_host.
1071 // - for hidden classes that are not strong: create a new CLD that has a class holder and
1072 // whose loader is the Lookup class's loader.
1073 // - for hidden class: add the class to the Lookup class's loader's CLD.
1074 if (is_unsafe_anon_class || cl_info.is_hidden()) {
1075 guarantee(!is_unsafe_anon_class || cl_info.unsafe_anonymous_host()->class_loader() == class_loader(),
1076 "should be NULL or the same");
1077 bool create_mirror_cld = is_unsafe_anon_class || !cl_info.is_strong_hidden();
1078 loader_data = register_loader(class_loader, create_mirror_cld);
1079 } else {
1080 loader_data = ClassLoaderData::class_loader_data(class_loader());
1081 }
1082
1083 assert(st != NULL, "invariant");
1084 assert(st->need_verify(), "invariant");
1085
1086 // Parse stream and create a klass.
1087 // Note that we do this even though this klass might
1088 // already be present in the SystemDictionary, otherwise we would not
1089 // throw potential ClassFormatErrors.
1090
1091 InstanceKlass* k = KlassFactory::create_from_stream(st,
1092 class_name,
1093 loader_data,
1094 cl_info,
1095 CHECK_NULL);
1096
1097 if ((cl_info.is_hidden() || is_unsafe_anon_class) && k != NULL) {
1098 // Hidden classes that are not strong and unsafe anonymous classes must update
1099 // ClassLoaderData holder so that they can be unloaded when the mirror is no
1100 // longer referenced.
1101 if (!cl_info.is_strong_hidden() || is_unsafe_anon_class) {
1102 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1103 }
1104
1105 {
1106 MutexLocker mu_r(THREAD, Compile_lock);
1107
1108 // Add to class hierarchy, initialize vtables, and do possible
1109 // deoptimizations.
1110 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1111 // But, do not add to dictionary.
1112 }
1113
1114 // Rewrite and patch constant pool here.
1115 k->link_class(CHECK_NULL);
1116 if (cl_info.cp_patches() != NULL) {
1117 k->constants()->patch_resolved_references(cl_info.cp_patches());
1118 }
1119
1120 // If it's anonymous, initialize it now, since nobody else will.
1121 if (is_unsafe_anon_class) {
1122 k->eager_initialize(CHECK_NULL);
1123 }
1124
1125 // notify jvmti
1126 if (JvmtiExport::should_post_class_load()) {
1127 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1128 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1129 }
1130 if (class_load_start_event.should_commit()) {
1131 post_class_load_event(&class_load_start_event, k, loader_data);
1132 }
1133 }
1134 assert(is_unsafe_anon_class || NULL == cl_info.cp_patches(),
1135 "cp_patches only found with unsafe_anonymous_host");
1136
1137 return k;
1138 }
1139
1140 // Add a klass to the system from a stream (called by jni_DefineClass and
1141 // JVM_DefineClass).
1142 // Note: class_name can be NULL. In that case we do not know the name of
1143 // the class until we have parsed the stream.
1144
1145 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1146 Handle class_loader,
1147 Handle protection_domain,
1148 ClassFileStream* st,
1149 TRAPS) {
1150
1151 HandleMark hm(THREAD);
1152
1153 // Classloaders that support parallelism, e.g. bootstrap classloader,
1154 // do not acquire lock here
1155 bool DoObjectLock = true;
1156 if (is_parallelCapable(class_loader)) {
1157 DoObjectLock = false;
1158 }
1159
1160 ClassLoaderData* loader_data = register_loader(class_loader);
1161
1162 // Make sure we are synchronized on the class loader before we proceed
1163 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1164 check_loader_lock_contention(lockObject, THREAD);
1165 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1166
1167 assert(st != NULL, "invariant");
1168
1169 // Parse the stream and create a klass.
1170 // Note that we do this even though this klass might
1171 // already be present in the SystemDictionary, otherwise we would not
1172 // throw potential ClassFormatErrors.
1173 InstanceKlass* k = NULL;
1174
1175 #if INCLUDE_CDS
1176 if (!DumpSharedSpaces) {
1177 k = SystemDictionaryShared::lookup_from_stream(class_name,
1178 class_loader,
1179 protection_domain,
1180 st,
1181 CHECK_NULL);
1182 }
1183 #endif
1184
1185 if (k == NULL) {
1186 if (st->buffer() == NULL) {
1187 return NULL;
1188 }
1189 ClassLoadInfo cl_info(protection_domain);
1190 k = KlassFactory::create_from_stream(st, class_name, loader_data, cl_info, CHECK_NULL);
1191 }
1192
1193 assert(k != NULL, "no klass created");
1194 Symbol* h_name = k->name();
1195 assert(class_name == NULL || class_name == h_name, "name mismatch");
1196
1197 // Add class just loaded
1198 // If a class loader supports parallel classloading handle parallel define requests
1199 // find_or_define_instance_class may return a different InstanceKlass
1200 if (is_parallelCapable(class_loader)) {
1201 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1202 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1203 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1204 assert(defined_k != NULL, "Should have a klass if there's no exception");
1205 loader_data->add_to_deallocate_list(k);
1206 k = defined_k;
1207 }
1208 } else {
1209 define_instance_class(k, THREAD);
1210 }
1211
1212 // If defining the class throws an exception register 'k' for cleanup.
1213 if (HAS_PENDING_EXCEPTION) {
1214 assert(k != NULL, "Must have an instance klass here!");
1215 loader_data->add_to_deallocate_list(k);
1216 return NULL;
1217 }
1218
1219 // Make sure we have an entry in the SystemDictionary on success
1220 debug_only( {
1221 MutexLocker mu(THREAD, SystemDictionary_lock);
1222
1223 Klass* check = find_class(h_name, k->class_loader_data());
1224 assert(check == k, "should be present in the dictionary");
1225 } );
1226
1227 return k;
1228 }
1229
1230 #if INCLUDE_CDS
1231 // Load a class for boot loader from the shared spaces. This also
1232 // forces the super class and all interfaces to be loaded.
1233 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1234 PackageEntry* pkg_entry,
1235 TRAPS) {
1236 assert(UseSharedSpaces, "Sanity check");
1237 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1238 if (ik != NULL && ik->is_shared_boot_class()) {
1239 return load_shared_class(ik, Handle(), Handle(), NULL, pkg_entry, THREAD);
1240 }
1241 return NULL;
1242 }
1243
1244 // Check if a shared class can be loaded by the specific classloader.
1245 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1246 InstanceKlass* ik,
1247 PackageEntry* pkg_entry,
1248 Handle class_loader, TRAPS) {
1249 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1250 "Cannot use sharing if java.base is patched");
1251
1252 // (1) Check if we are loading into the same loader as in dump time.
1253
1254 if (ik->is_shared_boot_class()) {
1255 if (class_loader() != NULL) {
1256 return false;
1257 }
1258 } else if (ik->is_shared_platform_class()) {
1259 if (class_loader() != java_platform_loader()) {
1260 return false;
1261 }
1262 } else if (ik->is_shared_app_class()) {
1263 if (class_loader() != java_system_loader()) {
1264 return false;
1265 }
1266 } else {
1267 // ik was loaded by a custom loader during dump time
1268 if (class_loader_data(class_loader)->is_builtin_class_loader_data()) {
1269 return false;
1270 } else {
1271 return true;
1272 }
1273 }
1274
1275 // (2) Check if we are loading into the same module from the same location as in dump time.
1276
1277 if (MetaspaceShared::use_optimized_module_handling()) {
1278 // Class visibility has not changed between dump time and run time, so a class
1279 // that was visible (and thus archived) during dump time is always visible during runtime.
1280 assert(SystemDictionary::is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader, THREAD),
1281 "visibility cannot change between dump time and runtime");
1282 return true;
1283 }
1284 return is_shared_class_visible_impl(class_name, ik, pkg_entry, class_loader, THREAD);
1285 }
1286
1287 bool SystemDictionary::is_shared_class_visible_impl(Symbol* class_name,
1288 InstanceKlass* ik,
1289 PackageEntry* pkg_entry,
1290 Handle class_loader, TRAPS) {
1291 int scp_index = ik->shared_classpath_index();
1292 assert(!ik->is_shared_unregistered_class(), "this function should be called for built-in classes only");
1293 assert(scp_index >= 0, "must be");
1294 SharedClassPathEntry* scp_entry = FileMapInfo::shared_path(scp_index);
1295 if (!Universe::is_module_initialized()) {
1296 assert(scp_entry != NULL && scp_entry->is_modules_image(),
1297 "Loading non-bootstrap classes before the module system is initialized");
1298 assert(class_loader.is_null(), "sanity");
1299 return true;
1300 }
1301
1302 ModuleEntry* mod_entry = (pkg_entry == NULL) ? NULL : pkg_entry->module();
1303 bool should_be_in_named_module = (mod_entry != NULL && mod_entry->is_named());
1304 bool was_archived_from_named_module = scp_entry->in_named_module();
1305 bool visible;
1306
1307 if (was_archived_from_named_module) {
1308 if (should_be_in_named_module) {
1309 // Is the module loaded from the same location as during dump time?
1310 visible = mod_entry->shared_path_index() == scp_index;
1311 if (visible) {
1312 assert(!mod_entry->is_patched(), "cannot load archived classes for patched module");
1313 }
1314 } else {
1315 // During dump time, this class was in a named module, but at run time, this class should be
1316 // in an unnamed module.
1317 visible = false;
1318 }
1319 } else {
1320 if (should_be_in_named_module) {
1321 // During dump time, this class was in an unnamed, but at run time, this class should be
1322 // in a named module.
1323 visible = false;
1324 } else {
1325 visible = true;
1326 }
1327 }
1328
1329 return visible;
1330 }
1331
1332 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1333 Handle class_loader, Handle protection_domain,
1334 bool is_superclass, TRAPS) {
1335 assert(super_type->is_shared(), "must be");
1336
1337 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1338 class_loader, protection_domain, is_superclass, CHECK_0);
1339 if (found == super_type) {
1340 return true;
1341 } else {
1342 // The dynamically resolved super type is not the same as the one we used during dump time,
1343 // so we cannot use the child class.
1344 return false;
1345 }
1346 }
1347
1348 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1349 Handle protection_domain, TRAPS) {
1350 // Check the superclass and interfaces. They must be the same
1351 // as in dump time, because the layout of <ik> depends on
1352 // the specific layout of ik->super() and ik->local_interfaces().
1353 //
1354 // If unexpected superclass or interfaces are found, we cannot
1355 // load <ik> from the shared archive.
1356
1357 if (ik->super() != NULL &&
1358 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1359 class_loader, protection_domain, true, THREAD)) {
1360 return false;
1361 }
1362
1363 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1364 int num_interfaces = interfaces->length();
1365 for (int index = 0; index < num_interfaces; index++) {
1366 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1367 return false;
1368 }
1369 }
1370
1371 return true;
1372 }
1373
1374 InstanceKlass* SystemDictionary::load_shared_lambda_proxy_class(InstanceKlass* ik,
1375 Handle class_loader,
1376 Handle protection_domain,
1377 PackageEntry* pkg_entry,
1378 TRAPS) {
1379 InstanceKlass* shared_nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1380 assert(shared_nest_host->is_shared(), "nest host must be in CDS archive");
1381 Symbol* cn = shared_nest_host->name();
1382 Klass *s = resolve_or_fail(cn, class_loader, protection_domain, true, CHECK_NULL);
1383 if (s != shared_nest_host) {
1384 // The dynamically resolved nest_host is not the same as the one we used during dump time,
1385 // so we cannot use ik.
1386 return NULL;
1387 } else {
1388 assert(s->is_shared(), "must be");
1389 }
1390
1391 // The lambda proxy class and its nest host have the same class loader and class loader data,
1392 // as verified in SystemDictionaryShared::add_lambda_proxy_class()
1393 assert(shared_nest_host->class_loader() == class_loader(), "mismatched class loader");
1394 assert(shared_nest_host->class_loader_data() == ClassLoaderData::class_loader_data(class_loader()), "mismatched class loader data");
1395 ik->set_nest_host(shared_nest_host, THREAD);
1396
1397 InstanceKlass* loaded_ik = load_shared_class(ik, class_loader, protection_domain, NULL, pkg_entry, CHECK_NULL);
1398
1399 assert(shared_nest_host->is_same_class_package(ik),
1400 "lambda proxy class and its nest host must be in the same package");
1401
1402 return loaded_ik;
1403 }
1404
1405 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1406 Handle class_loader,
1407 Handle protection_domain,
1408 const ClassFileStream *cfs,
1409 PackageEntry* pkg_entry,
1410 TRAPS) {
1411 assert(ik != NULL, "sanity");
1412 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1413 Symbol* class_name = ik->name();
1414
1415 bool visible = is_shared_class_visible(
1416 class_name, ik, pkg_entry, class_loader, CHECK_NULL);
1417 if (!visible) {
1418 return NULL;
1419 }
1420
1421 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1422 return NULL;
1423 }
1424
1425 InstanceKlass* new_ik = NULL;
1426 // CFLH check is skipped for VM hidden or anonymous classes (see KlassFactory::create_from_stream).
1427 // It will be skipped for shared VM hidden lambda proxy classes.
1428 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1429 new_ik = KlassFactory::check_shared_class_file_load_hook(
1430 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1431 }
1432 if (new_ik != NULL) {
1433 // The class is changed by CFLH. Return the new class. The shared class is
1434 // not used.
1435 return new_ik;
1436 }
1437
1438 // Adjust methods to recover missing data. They need addresses for
1439 // interpreter entry points and their default native method address
1440 // must be reset.
1441
1442 // Updating methods must be done under a lock so multiple
1443 // threads don't update these in parallel
1444 //
1445 // Shared classes are all currently loaded by either the bootstrap or
1446 // internal parallel class loaders, so this will never cause a deadlock
1447 // on a custom class loader lock.
1448
1449 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1450 {
1451 HandleMark hm(THREAD);
1452 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1453 check_loader_lock_contention(lockObject, THREAD);
1454 ObjectLocker ol(lockObject, THREAD, true);
1455 // prohibited package check assumes all classes loaded from archive call
1456 // restore_unshareable_info which calls ik->set_package()
1457 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1458 }
1459
1460 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1461 return ik;
1462 }
1463
1464 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1465 ik->print_class_load_logging(loader_data, NULL, NULL);
1466
1467 // For boot loader, ensure that GetSystemPackage knows that a class in this
1468 // package was loaded.
1469 if (loader_data->is_the_null_class_loader_data()) {
1470 int path_index = ik->shared_classpath_index();
1471 ik->set_classpath_index(path_index, THREAD);
1472 }
1473
1474 // notify a class loaded from shared object
1475 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1476
1477 ik->set_has_passed_fingerprint_check(false);
1478 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1479 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1480 uint64_t cds_fp = ik->get_stored_fingerprint();
1481 if (aot_fp != 0 && aot_fp == cds_fp) {
1482 // This class matches with a class saved in an AOT library
1483 ik->set_has_passed_fingerprint_check(true);
1484 } else {
1485 if (log_is_enabled(Info, class, fingerprint)) {
1486 ResourceMark rm(THREAD);
1487 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1488 }
1489 }
1490 }
1491 }
1492
1493 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1494 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1495 assert(klass->is_shared(), "Must be shared class");
1496 if (klass->class_loader_data() != NULL) {
1497 return;
1498 }
1499
1500 // add super and interfaces first
1501 Klass* super = klass->super();
1502 if (super != NULL && super->class_loader_data() == NULL) {
1503 assert(super->is_instance_klass(), "Super should be instance klass");
1504 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1505 }
1506
1507 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1508 for (int i = 0; i < ifs->length(); i++) {
1509 InstanceKlass* ik = ifs->at(i);
1510 if (ik->class_loader_data() == NULL) {
1511 quick_resolve(ik, loader_data, domain, CHECK);
1512 }
1513 }
1514
1515 klass->restore_unshareable_info(loader_data, domain, NULL, THREAD);
1516 load_shared_class_misc(klass, loader_data, CHECK);
1517 Dictionary* dictionary = loader_data->dictionary();
1518 unsigned int hash = dictionary->compute_hash(klass->name());
1519 dictionary->add_klass(hash, klass->name(), klass);
1520 add_to_hierarchy(klass, CHECK);
1521 assert(klass->is_loaded(), "Must be in at least loaded state");
1522 }
1523 #endif // INCLUDE_CDS
1524
1525 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1526
1527 if (class_loader.is_null()) {
1528 ResourceMark rm(THREAD);
1529 PackageEntry* pkg_entry = NULL;
1530 bool search_only_bootloader_append = false;
1531 ClassLoaderData *loader_data = class_loader_data(class_loader);
1532
1533 // Find the package in the boot loader's package entry table.
1534 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1535 if (pkg_name != NULL) {
1536 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1537 }
1538
1539 // Prior to attempting to load the class, enforce the boot loader's
1540 // visibility boundaries.
1541 if (!Universe::is_module_initialized()) {
1542 // During bootstrapping, prior to module initialization, any
1543 // class attempting to be loaded must be checked against the
1544 // java.base packages in the boot loader's PackageEntryTable.
1545 // No class outside of java.base is allowed to be loaded during
1546 // this bootstrapping window.
1547 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1548 // Class is either in the unnamed package or in
1549 // a named package within the unnamed module. Either
1550 // case is outside of java.base, do not attempt to
1551 // load the class post java.base definition. If
1552 // java.base has not been defined, let the class load
1553 // and its package will be checked later by
1554 // ModuleEntryTable::verify_javabase_packages.
1555 if (ModuleEntryTable::javabase_defined()) {
1556 return NULL;
1557 }
1558 } else {
1559 // Check that the class' package is defined within java.base.
1560 ModuleEntry* mod_entry = pkg_entry->module();
1561 Symbol* mod_entry_name = mod_entry->name();
1562 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1563 return NULL;
1564 }
1565 }
1566 } else {
1567 // After the module system has been initialized, check if the class'
1568 // package is in a module defined to the boot loader.
1569 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1570 // Class is either in the unnamed package, in a named package
1571 // within a module not defined to the boot loader or in a
1572 // a named package within the unnamed module. In all cases,
1573 // limit visibility to search for the class only in the boot
1574 // loader's append path.
1575 if (!ClassLoader::has_bootclasspath_append()) {
1576 // If there is no bootclasspath append entry, no need to continue
1577 // searching.
1578 return NULL;
1579 }
1580 search_only_bootloader_append = true;
1581 }
1582 }
1583
1584 // Prior to bootstrapping's module initialization, never load a class outside
1585 // of the boot loader's module path
1586 assert(Universe::is_module_initialized() ||
1587 !search_only_bootloader_append,
1588 "Attempt to load a class outside of boot loader's module path");
1589
1590 // Search for classes in the CDS archive.
1591 InstanceKlass* k = NULL;
1592
1593 #if INCLUDE_CDS
1594 if (UseSharedSpaces)
1595 {
1596 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1597 k = load_shared_boot_class(class_name, pkg_entry, THREAD);
1598 }
1599 #endif
1600
1601 if (k == NULL) {
1602 // Use VM class loader
1603 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1604 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1605 }
1606
1607 // find_or_define_instance_class may return a different InstanceKlass
1608 if (k != NULL) {
1609 InstanceKlass* defined_k =
1610 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1611 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1612 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1613 assert(defined_k != NULL, "Should have a klass if there's no exception");
1614 loader_data->add_to_deallocate_list(k);
1615 k = defined_k;
1616 } else if (HAS_PENDING_EXCEPTION) {
1617 loader_data->add_to_deallocate_list(k);
1618 return NULL;
1619 }
1620 }
1621 return k;
1622 } else {
1623 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1624 ResourceMark rm(THREAD);
1625
1626 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1627 JavaThread* jt = (JavaThread*) THREAD;
1628
1629 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1630 ClassLoader::perf_app_classload_selftime(),
1631 ClassLoader::perf_app_classload_count(),
1632 jt->get_thread_stat()->perf_recursion_counts_addr(),
1633 jt->get_thread_stat()->perf_timers_addr(),
1634 PerfClassTraceTime::CLASS_LOAD);
1635
1636 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1637 // Translate to external class name format, i.e., convert '/' chars to '.'
1638 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1639
1640 JavaValue result(T_OBJECT);
1641
1642 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1643
1644 // Call public unsynchronized loadClass(String) directly for all class loaders.
1645 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1646 // acquire a class-name based lock rather than the class loader object lock.
1647 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1648 JavaCalls::call_virtual(&result,
1649 class_loader,
1650 spec_klass,
1651 vmSymbols::loadClass_name(),
1652 vmSymbols::string_class_signature(),
1653 string,
1654 CHECK_NULL);
1655
1656 assert(result.get_type() == T_OBJECT, "just checking");
1657 oop obj = (oop) result.get_jobject();
1658
1659 // Primitive classes return null since forName() can not be
1660 // used to obtain any of the Class objects representing primitives or void
1661 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1662 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1663 // For user defined Java class loaders, check that the name returned is
1664 // the same as that requested. This check is done for the bootstrap
1665 // loader when parsing the class file.
1666 if (class_name == k->name()) {
1667 return k;
1668 }
1669 }
1670 // Class is not found or has the wrong name, return NULL
1671 return NULL;
1672 }
1673 }
1674
1675 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1676 EventClassDefine event;
1677 if (event.should_commit()) {
1678 event.set_definedClass(k);
1679 event.set_definingClassLoader(def_cld);
1680 event.commit();
1681 }
1682 }
1683
1684 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1685
1686 HandleMark hm(THREAD);
1687 ClassLoaderData* loader_data = k->class_loader_data();
1688 Handle class_loader_h(THREAD, loader_data->class_loader());
1689
1690 // for bootstrap and other parallel classloaders don't acquire lock,
1691 // use placeholder token
1692 // If a parallelCapable class loader calls define_instance_class instead of
1693 // find_or_define_instance_class to get here, we have a timing
1694 // hole with systemDictionary updates and check_constraints
1695 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1696 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1697 compute_loader_lock_object(class_loader_h, THREAD)),
1698 "define called without lock");
1699 }
1700
1701 // Check class-loading constraints. Throw exception if violation is detected.
1702 // Grabs and releases SystemDictionary_lock
1703 // The check_constraints/find_class call and update_dictionary sequence
1704 // must be "atomic" for a specific class/classloader pair so we never
1705 // define two different instanceKlasses for that class/classloader pair.
1706 // Existing classloaders will call define_instance_class with the
1707 // classloader lock held
1708 // Parallel classloaders will call find_or_define_instance_class
1709 // which will require a token to perform the define class
1710 Symbol* name_h = k->name();
1711 Dictionary* dictionary = loader_data->dictionary();
1712 unsigned int d_hash = dictionary->compute_hash(name_h);
1713 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1714
1715 // Register class just loaded with class loader (placed in ArrayList)
1716 // Note we do this before updating the dictionary, as this can
1717 // fail with an OutOfMemoryError (if it does, we will *not* put this
1718 // class in the dictionary and will not update the class hierarchy).
1719 // JVMTI FollowReferences needs to find the classes this way.
1720 if (k->class_loader() != NULL) {
1721 methodHandle m(THREAD, Universe::loader_addClass_method());
1722 JavaValue result(T_VOID);
1723 JavaCallArguments args(class_loader_h);
1724 args.push_oop(Handle(THREAD, k->java_mirror()));
1725 JavaCalls::call(&result, m, &args, CHECK);
1726 }
1727
1728 // Add the new class. We need recompile lock during update of CHA.
1729 {
1730 unsigned int p_hash = placeholders()->compute_hash(name_h);
1731 int p_index = placeholders()->hash_to_index(p_hash);
1732
1733 MutexLocker mu_r(THREAD, Compile_lock);
1734
1735 // Add to class hierarchy, initialize vtables, and do possible
1736 // deoptimizations.
1737 add_to_hierarchy(k, CHECK); // No exception, but can block
1738
1739 // Add to systemDictionary - so other classes can see it.
1740 // Grabs and releases SystemDictionary_lock
1741 update_dictionary(d_hash, p_index, p_hash,
1742 k, class_loader_h, THREAD);
1743 }
1744 k->eager_initialize(THREAD);
1745
1746 // notify jvmti
1747 if (JvmtiExport::should_post_class_load()) {
1748 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1749 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1750
1751 }
1752 post_class_define_event(k, loader_data);
1753 }
1754
1755 // Support parallel classloading
1756 // All parallel class loaders, including bootstrap classloader
1757 // lock a placeholder entry for this class/class_loader pair
1758 // to allow parallel defines of different classes for this class loader
1759 // With AllowParallelDefine flag==true, in case they do not synchronize around
1760 // FindLoadedClass/DefineClass, calls, we check for parallel
1761 // loading for them, wait if a defineClass is in progress
1762 // and return the initial requestor's results
1763 // This flag does not apply to the bootstrap classloader.
1764 // With AllowParallelDefine flag==false, call through to define_instance_class
1765 // which will throw LinkageError: duplicate class definition.
1766 // False is the requested default.
1767 // For better performance, the class loaders should synchronize
1768 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1769 // potentially waste time reading and parsing the bytestream.
1770 // Note: VM callers should ensure consistency of k/class_name,class_loader
1771 // Be careful when modifying this code: once you have run
1772 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1773 // you need to find_and_remove it before returning.
1774 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1775 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1776 InstanceKlass* k, TRAPS) {
1777
1778 Symbol* name_h = k->name(); // passed in class_name may be null
1779 ClassLoaderData* loader_data = class_loader_data(class_loader);
1780 Dictionary* dictionary = loader_data->dictionary();
1781
1782 unsigned int d_hash = dictionary->compute_hash(name_h);
1783
1784 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1785 unsigned int p_hash = placeholders()->compute_hash(name_h);
1786 int p_index = placeholders()->hash_to_index(p_hash);
1787 PlaceholderEntry* probe;
1788
1789 {
1790 MutexLocker mu(THREAD, SystemDictionary_lock);
1791 // First check if class already defined
1792 if (is_parallelDefine(class_loader)) {
1793 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1794 if (check != NULL) {
1795 return check;
1796 }
1797 }
1798
1799 // Acquire define token for this class/classloader
1800 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1801 // Wait if another thread defining in parallel
1802 // All threads wait - even those that will throw duplicate class: otherwise
1803 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1804 // if other thread has not finished updating dictionary
1805 while (probe->definer() != NULL) {
1806 SystemDictionary_lock->wait();
1807 }
1808 // Only special cases allow parallel defines and can use other thread's results
1809 // Other cases fall through, and may run into duplicate defines
1810 // caught by finding an entry in the SystemDictionary
1811 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1812 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1813 SystemDictionary_lock->notify_all();
1814 #ifdef ASSERT
1815 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1816 assert(check != NULL, "definer missed recording success");
1817 #endif
1818 return probe->instance_klass();
1819 } else {
1820 // This thread will define the class (even if earlier thread tried and had an error)
1821 probe->set_definer(THREAD);
1822 }
1823 }
1824
1825 define_instance_class(k, THREAD);
1826
1827 Handle linkage_exception = Handle(); // null handle
1828
1829 // definer must notify any waiting threads
1830 {
1831 MutexLocker mu(THREAD, SystemDictionary_lock);
1832 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1833 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1834 if (probe != NULL) {
1835 if (HAS_PENDING_EXCEPTION) {
1836 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1837 CLEAR_PENDING_EXCEPTION;
1838 } else {
1839 probe->set_instance_klass(k);
1840 }
1841 probe->set_definer(NULL);
1842 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1843 SystemDictionary_lock->notify_all();
1844 }
1845 }
1846
1847 // Can't throw exception while holding lock due to rank ordering
1848 if (linkage_exception() != NULL) {
1849 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1850 }
1851
1852 return k;
1853 }
1854
1855 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1856 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1857 if (class_loader.is_null()) {
1858 return Handle(THREAD, _system_loader_lock_obj.resolve());
1859 } else {
1860 return class_loader;
1861 }
1862 }
1863
1864 // This method is added to check how often we have to wait to grab loader
1865 // lock. The results are being recorded in the performance counters defined in
1866 // ClassLoader::_sync_systemLoaderLockContentionRate and
1867 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1868 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1869 if (!UsePerfData) {
1870 return;
1871 }
1872
1873 assert(!loader_lock.is_null(), "NULL lock object");
1874
1875 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1876 == ObjectSynchronizer::owner_other) {
1877 // contention will likely happen, so increment the corresponding
1878 // contention counter.
1879 if (loader_lock() == _system_loader_lock_obj.resolve()) {
1880 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1881 } else {
1882 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1883 }
1884 }
1885 }
1886
1887 // ----------------------------------------------------------------------------
1888 // Lookup
1889
1890 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1891 Symbol* class_name,
1892 Dictionary* dictionary) {
1893 assert_locked_or_safepoint(SystemDictionary_lock);
1894 int index = dictionary->hash_to_index(hash);
1895 return dictionary->find_class(index, hash, class_name);
1896 }
1897
1898
1899 // Basic find on classes in the midst of being loaded
1900 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1901 ClassLoaderData* loader_data) {
1902 assert_locked_or_safepoint(SystemDictionary_lock);
1903 unsigned int p_hash = placeholders()->compute_hash(class_name);
1904 int p_index = placeholders()->hash_to_index(p_hash);
1905 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1906 }
1907
1908
1909 // Used for assertions and verification only
1910 // Precalculating the hash and index is an optimization because there are many lookups
1911 // before adding the class.
1912 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1913 assert_locked_or_safepoint(SystemDictionary_lock);
1914 #ifndef ASSERT
1915 guarantee(VerifyBeforeGC ||
1916 VerifyDuringGC ||
1917 VerifyBeforeExit ||
1918 VerifyDuringStartup ||
1919 VerifyAfterGC, "too expensive");
1920 #endif
1921
1922 Dictionary* dictionary = loader_data->dictionary();
1923 unsigned int d_hash = dictionary->compute_hash(class_name);
1924 return find_class(d_hash, class_name, dictionary);
1925 }
1926
1927
1928 // ----------------------------------------------------------------------------
1929 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1930 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1931 // before a new class is used.
1932
1933 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1934 assert(k != NULL, "just checking");
1935 if (Universe::is_fully_initialized()) {
1936 assert_locked_or_safepoint(Compile_lock);
1937 }
1938
1939 k->set_init_state(InstanceKlass::loaded);
1940 // make sure init_state store is already done.
1941 // The compiler reads the hierarchy outside of the Compile_lock.
1942 // Access ordering is used to add to hierarchy.
1943
1944 // Link into hierachy.
1945 k->append_to_sibling_list(); // add to superklass/sibling list
1946 k->process_interfaces(THREAD); // handle all "implements" declarations
1947
1948 // Now flush all code that depended on old class hierarchy.
1949 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1950 if (Universe::is_fully_initialized()) {
1951 CodeCache::flush_dependents_on(k);
1952 }
1953 }
1954
1955 // ----------------------------------------------------------------------------
1956 // GC support
1957
1958 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1959 // Note: anonymous classes are not in the SD.
1960 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1961
1962 bool unloading_occurred;
1963 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1964 {
1965 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1966 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1967 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1968 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1969 if (unloading_occurred) {
1970 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1971 JFR_ONLY(Jfr::on_unloading_classes();)
1972
1973 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1974 ClassLoaderDataGraph::clean_module_and_package_info();
1975 constraints()->purge_loader_constraints();
1976 resolution_errors()->purge_resolution_errors();
1977 }
1978 }
1979
1980 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1981
1982 if (unloading_occurred) {
1983 SymbolTable::trigger_cleanup();
1984
1985 // Oops referenced by the protection domain cache table may get unreachable independently
1986 // of the class loader (eg. cached protection domain oops). So we need to
1987 // explicitly unlink them here.
1988 // All protection domain oops are linked to the caller class, so if nothing
1989 // unloads, this is not needed.
1990 _pd_cache_table->trigger_cleanup();
1991 }
1992
1993 return unloading_occurred;
1994 }
1995
1996 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1997 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1998 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1999 it->push(well_known_klass_addr((WKID)id));
2000 }
2001 }
2002
2003 void SystemDictionary::methods_do(void f(Method*)) {
2004 // Walk methods in loaded classes
2005 MutexLocker ml(ClassLoaderDataGraph_lock);
2006 ClassLoaderDataGraph::methods_do(f);
2007 // Walk method handle intrinsics
2008 invoke_method_table()->methods_do(f);
2009 }
2010
2011 // ----------------------------------------------------------------------------
2012 // Initialization
2013
2014 void SystemDictionary::initialize(TRAPS) {
2015 // Allocate arrays
2016 _placeholders = new PlaceholderTable(_placeholder_table_size);
2017 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2018 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2019 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2020 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2021
2022 // Allocate private object used as system class loader lock
2023 oop lock_obj = oopFactory::new_intArray(0, CHECK);
2024 _system_loader_lock_obj = OopHandle(Universe::vm_global(), lock_obj);
2025
2026 // Initialize basic classes
2027 resolve_well_known_classes(CHECK);
2028 }
2029
2030 // Compact table of directions on the initialization of klasses:
2031 static const short wk_init_info[] = {
2032 #define WK_KLASS_INIT_INFO(name, symbol) \
2033 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
2034
2035 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2036 #undef WK_KLASS_INIT_INFO
2037 0
2038 };
2039
2040 #ifdef ASSERT
2041 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
2042 int sid;
2043 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
2044 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2045 if (class_name == symbol) {
2046 return true;
2047 }
2048 }
2049 return false;
2050 }
2051 #endif
2052
2053 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
2054 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2055 int sid = wk_init_info[id - FIRST_WKID];
2056 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2057 InstanceKlass** klassp = &_well_known_klasses[id];
2058
2059 #if INCLUDE_CDS
2060 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
2061 InstanceKlass* k = *klassp;
2062 assert(k->is_shared_boot_class(), "must be");
2063
2064 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
2065 quick_resolve(k, loader_data, Handle(), CHECK_false);
2066 return true;
2067 }
2068 #endif // INCLUDE_CDS
2069
2070 if (!is_wk_klass_loaded(*klassp)) {
2071 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
2072 (*klassp) = InstanceKlass::cast(k);
2073 }
2074 return ((*klassp) != NULL);
2075 }
2076
2077 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2078 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2079 for (int id = (int)start_id; id < (int)limit_id; id++) {
2080 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2081 resolve_wk_klass((WKID)id, CHECK);
2082 }
2083
2084 // move the starting value forward to the limit:
2085 start_id = limit_id;
2086 }
2087
2088 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2089 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
2090
2091 // Create the ModuleEntry for java.base. This call needs to be done here,
2092 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2093 ClassLoader::classLoader_init2(CHECK);
2094
2095 // Preload commonly used klasses
2096 WKID scan = FIRST_WKID;
2097 // first do Object, then String, Class
2098 #if INCLUDE_CDS
2099 if (UseSharedSpaces) {
2100 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2101
2102 // It's unsafe to access the archived heap regions before they
2103 // are fixed up, so we must do the fixup as early as possible
2104 // before the archived java objects are accessed by functions
2105 // such as java_lang_Class::restore_archived_mirror and
2106 // ConstantPool::restore_unshareable_info (restores the archived
2107 // resolved_references array object).
2108 //
2109 // HeapShared::fixup_mapped_heap_regions() fills the empty
2110 // spaces in the archived heap regions and may use
2111 // SystemDictionary::Object_klass(), so we can do this only after
2112 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2113 // call. No mirror objects are accessed/restored in the above call.
2114 // Mirrors are restored after java.lang.Class is loaded.
2115 HeapShared::fixup_mapped_heap_regions();
2116 CDS_JAVA_HEAP_ONLY(ClassLoaderDataShared::restore_archived_oops_for_null_class_loader_data());
2117
2118 // Initialize the constant pool for the Object_class
2119 assert(Object_klass()->is_shared(), "must be");
2120 Object_klass()->constants()->restore_unshareable_info(CHECK);
2121 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2122 } else
2123 #endif
2124 {
2125 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2126 }
2127
2128 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2129
2130 java_lang_Object::register_natives(CHECK);
2131
2132 // Calculate offsets for String and Class classes since they are loaded and
2133 // can be used after this point.
2134 java_lang_String::compute_offsets();
2135 java_lang_Class::compute_offsets();
2136
2137 // Fixup mirrors for classes loaded before java.lang.Class.
2138 Universe::initialize_basic_type_mirrors(CHECK);
2139 Universe::fixup_mirrors(CHECK);
2140
2141 // do a bunch more:
2142 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2143
2144 // The offsets for jlr.Reference must be computed before
2145 // InstanceRefKlass::update_nonstatic_oop_maps is called. That function uses
2146 // the offsets to remove the referent and discovered fields from the oop maps,
2147 // as they are treated in a special way by the GC. Removing these oops from the
2148 // oop maps must be done before the usual subclasses of jlr.Reference are loaded.
2149 java_lang_ref_Reference::compute_offsets();
2150
2151 // Preload ref klasses and set reference types
2152 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2153 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2154
2155 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2156 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2157 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2158 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2159 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2160
2161 // JSR 292 classes
2162 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2163 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2164 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2165 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2166 WKID last = WKID_LIMIT;
2167 resolve_wk_klasses_until(last, scan, CHECK);
2168
2169 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2170 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2171 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2172 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2173 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2174 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2175 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2176 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2177 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2178 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2179
2180 if (DiagnoseSyncOnPrimitiveWrappers != 0) {
2181 for (int i = T_BOOLEAN; i < T_LONG + 1; i++) {
2182 assert(_box_klasses[i] != NULL, "NULL box class");
2183 _box_klasses[i]->set_is_box();
2184 _box_klasses[i]->set_prototype_header(markWord::prototype());
2185 }
2186 }
2187
2188 #ifdef ASSERT
2189 if (UseSharedSpaces) {
2190 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2191 "All well known classes must be resolved in JVMTI early phase"));
2192 for (int i = FIRST_WKID; i < last; i++) {
2193 InstanceKlass* k = _well_known_klasses[i];
2194 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2195 }
2196 }
2197 #endif
2198 }
2199
2200 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2201 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2202 BasicType SystemDictionary::box_klass_type(Klass* k) {
2203 assert(k != NULL, "");
2204 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2205 if (_box_klasses[i] == k)
2206 return (BasicType)i;
2207 }
2208 return T_OBJECT;
2209 }
2210
2211 // Constraints on class loaders. The details of the algorithm can be
2212 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2213 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2214 // that the dictionary needs to maintain a set of contraints that
2215 // must be satisfied by all classes in the dictionary.
2216 // if defining is true, then LinkageError if already in dictionary
2217 // if initiating loader, then ok if InstanceKlass matches existing entry
2218
2219 void SystemDictionary::check_constraints(unsigned int d_hash,
2220 InstanceKlass* k,
2221 Handle class_loader,
2222 bool defining,
2223 TRAPS) {
2224 ResourceMark rm(THREAD);
2225 stringStream ss;
2226 bool throwException = false;
2227
2228 {
2229 Symbol *name = k->name();
2230 ClassLoaderData *loader_data = class_loader_data(class_loader);
2231
2232 MutexLocker mu(THREAD, SystemDictionary_lock);
2233
2234 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2235 if (check != NULL) {
2236 // If different InstanceKlass - duplicate class definition,
2237 // else - ok, class loaded by a different thread in parallel.
2238 // We should only have found it if it was done loading and ok to use.
2239 // The dictionary only holds instance classes, placeholders
2240 // also hold array classes.
2241
2242 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2243 if ((defining == true) || (k != check)) {
2244 throwException = true;
2245 ss.print("loader %s", loader_data->loader_name_and_id());
2246 ss.print(" attempted duplicate %s definition for %s. (%s)",
2247 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2248 } else {
2249 return;
2250 }
2251 }
2252
2253 #ifdef ASSERT
2254 Symbol* ph_check = find_placeholder(name, loader_data);
2255 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2256 #endif
2257
2258 if (throwException == false) {
2259 if (constraints()->check_or_update(k, class_loader, name) == false) {
2260 throwException = true;
2261 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2262 ss.print(" wants to load %s %s.",
2263 k->external_kind(), k->external_name());
2264 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2265 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2266 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2267 existing_klass->external_kind(),
2268 existing_klass->class_loader_data()->loader_name_and_id(),
2269 existing_klass->class_in_module_of_loader(false, true));
2270 } else {
2271 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2272 }
2273 }
2274 }
2275 }
2276
2277 // Throw error now if needed (cannot throw while holding
2278 // SystemDictionary_lock because of rank ordering)
2279 if (throwException == true) {
2280 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2281 }
2282 }
2283
2284 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2285 // have been called.
2286 void SystemDictionary::update_dictionary(unsigned int d_hash,
2287 int p_index, unsigned int p_hash,
2288 InstanceKlass* k,
2289 Handle class_loader,
2290 TRAPS) {
2291 // Compile_lock prevents systemDictionary updates during compilations
2292 assert_locked_or_safepoint(Compile_lock);
2293 Symbol* name = k->name();
2294 ClassLoaderData *loader_data = class_loader_data(class_loader);
2295
2296 {
2297 MutexLocker mu1(THREAD, SystemDictionary_lock);
2298
2299 // Make a new dictionary entry.
2300 Dictionary* dictionary = loader_data->dictionary();
2301 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2302 if (sd_check == NULL) {
2303 dictionary->add_klass(d_hash, name, k);
2304 }
2305 #ifdef ASSERT
2306 sd_check = find_class(d_hash, name, dictionary);
2307 assert (sd_check != NULL, "should have entry in dictionary");
2308 // Note: there may be a placeholder entry: for circularity testing
2309 // or for parallel defines
2310 #endif
2311 SystemDictionary_lock->notify_all();
2312 }
2313 }
2314
2315
2316 // Try to find a class name using the loader constraints. The
2317 // loader constraints might know about a class that isn't fully loaded
2318 // yet and these will be ignored.
2319 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2320 Symbol* class_name, Handle class_loader, TRAPS) {
2321
2322 // First see if it has been loaded directly.
2323 // Force the protection domain to be null. (This removes protection checks.)
2324 Handle no_protection_domain;
2325 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2326 no_protection_domain, CHECK_NULL);
2327 if (klass != NULL)
2328 return klass;
2329
2330 // Now look to see if it has been loaded elsewhere, and is subject to
2331 // a loader constraint that would require this loader to return the
2332 // klass that is already loaded.
2333 if (Signature::is_array(class_name)) {
2334 // For array classes, their Klass*s are not kept in the
2335 // constraint table. The element Klass*s are.
2336 SignatureStream ss(class_name, false);
2337 int ndims = ss.skip_array_prefix(); // skip all '['s
2338 BasicType t = ss.type();
2339 if (t != T_OBJECT) {
2340 klass = Universe::typeArrayKlassObj(t);
2341 } else {
2342 MutexLocker mu(THREAD, SystemDictionary_lock);
2343 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2344 }
2345 // If element class already loaded, allocate array klass
2346 if (klass != NULL) {
2347 klass = klass->array_klass_or_null(ndims);
2348 }
2349 } else {
2350 MutexLocker mu(THREAD, SystemDictionary_lock);
2351 // Non-array classes are easy: simply check the constraint table.
2352 klass = constraints()->find_constrained_klass(class_name, class_loader);
2353 }
2354
2355 return klass;
2356 }
2357
2358 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2359 Klass* klass_being_linked,
2360 Handle class_loader1,
2361 Handle class_loader2,
2362 Thread* THREAD) {
2363 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2364 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2365
2366 Symbol* constraint_name = NULL;
2367
2368 if (!Signature::is_array(class_name)) {
2369 constraint_name = class_name;
2370 } else {
2371 // For array classes, their Klass*s are not kept in the
2372 // constraint table. The element classes are.
2373 SignatureStream ss(class_name, false);
2374 ss.skip_array_prefix(); // skip all '['s
2375 if (!ss.has_envelope()) {
2376 return true; // primitive types always pass
2377 }
2378 constraint_name = ss.as_symbol();
2379 // Increment refcount to keep constraint_name alive after
2380 // SignatureStream is destructed. It will be decremented below
2381 // before returning.
2382 constraint_name->increment_refcount();
2383 }
2384
2385 Dictionary* dictionary1 = loader_data1->dictionary();
2386 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2387
2388 Dictionary* dictionary2 = loader_data2->dictionary();
2389 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2390
2391 {
2392 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2393 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2394 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2395 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2396 klass2, class_loader2);
2397 #if INCLUDE_CDS
2398 if (Arguments::is_dumping_archive() && klass_being_linked != NULL &&
2399 !klass_being_linked->is_shared()) {
2400 SystemDictionaryShared::record_linking_constraint(constraint_name,
2401 InstanceKlass::cast(klass_being_linked),
2402 class_loader1, class_loader2, THREAD);
2403 }
2404 #endif // INCLUDE_CDS
2405 if (Signature::is_array(class_name)) {
2406 constraint_name->decrement_refcount();
2407 }
2408 return result;
2409 }
2410 }
2411
2412 // Add entry to resolution error table to record the error when the first
2413 // attempt to resolve a reference to a class has failed.
2414 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2415 Symbol* error, Symbol* message) {
2416 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2417 int index = resolution_errors()->hash_to_index(hash);
2418 {
2419 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2420 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2421 }
2422 }
2423
2424 // Delete a resolution error for RedefineClasses for a constant pool is going away
2425 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2426 resolution_errors()->delete_entry(pool);
2427 }
2428
2429 // Lookup resolution error table. Returns error if found, otherwise NULL.
2430 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2431 Symbol** message) {
2432 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2433 int index = resolution_errors()->hash_to_index(hash);
2434 {
2435 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2436 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2437 if (entry != NULL) {
2438 *message = entry->message();
2439 return entry->error();
2440 } else {
2441 return NULL;
2442 }
2443 }
2444 }
2445
2446 // Add an entry to resolution error table to record an error in resolving or
2447 // validating a nest host. This is used to construct informative error
2448 // messages when IllegalAccessError's occur. If an entry already exists it will
2449 // be updated with the nest host error message.
2450 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
2451 int which,
2452 const char* message) {
2453 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2454 int index = resolution_errors()->hash_to_index(hash);
2455 {
2456 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2457 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2458 if (entry != NULL) {
2459 assert(entry->nest_host_error() == NULL, "Nest host error message already set!");
2460 entry->set_nest_host_error(message);
2461 } else {
2462 resolution_errors()->add_entry(index, hash, pool, which, message);
2463 }
2464 }
2465 }
2466
2467 // Lookup any nest host error
2468 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
2469 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2470 int index = resolution_errors()->hash_to_index(hash);
2471 {
2472 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2473 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2474 if (entry != NULL) {
2475 return entry->nest_host_error();
2476 } else {
2477 return NULL;
2478 }
2479 }
2480 }
2481
2482
2483 // Signature constraints ensure that callers and callees agree about
2484 // the meaning of type names in their signatures. This routine is the
2485 // intake for constraints. It collects them from several places:
2486 //
2487 // * LinkResolver::resolve_method (if check_access is true) requires
2488 // that the resolving class (the caller) and the defining class of
2489 // the resolved method (the callee) agree on each type in the
2490 // method's signature.
2491 //
2492 // * LinkResolver::resolve_interface_method performs exactly the same
2493 // checks.
2494 //
2495 // * LinkResolver::resolve_field requires that the constant pool
2496 // attempting to link to a field agree with the field's defining
2497 // class about the type of the field signature.
2498 //
2499 // * klassVtable::initialize_vtable requires that, when a class
2500 // overrides a vtable entry allocated by a superclass, that the
2501 // overriding method (i.e., the callee) agree with the superclass
2502 // on each type in the method's signature.
2503 //
2504 // * klassItable::initialize_itable requires that, when a class fills
2505 // in its itables, for each non-abstract method installed in an
2506 // itable, the method (i.e., the callee) agree with the interface
2507 // on each type in the method's signature.
2508 //
2509 // All those methods have a boolean (check_access, checkconstraints)
2510 // which turns off the checks. This is used from specialized contexts
2511 // such as bootstrapping, dumping, and debugging.
2512 //
2513 // No direct constraint is placed between the class and its
2514 // supertypes. Constraints are only placed along linked relations
2515 // between callers and callees. When a method overrides or implements
2516 // an abstract method in a supertype (superclass or interface), the
2517 // constraints are placed as if the supertype were the caller to the
2518 // overriding method. (This works well, since callers to the
2519 // supertype have already established agreement between themselves and
2520 // the supertype.) As a result of all this, a class can disagree with
2521 // its supertype about the meaning of a type name, as long as that
2522 // class neither calls a relevant method of the supertype, nor is
2523 // called (perhaps via an override) from the supertype.
2524 //
2525 //
2526 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
2527 //
2528 // Make sure all class components (including arrays) in the given
2529 // signature will be resolved to the same class in both loaders.
2530 // Returns the name of the type that failed a loader constraint check, or
2531 // NULL if no constraint failed. No exception except OOME is thrown.
2532 // Arrays are not added to the loader constraint table, their elements are.
2533 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2534 Klass* klass_being_linked,
2535 Handle loader1, Handle loader2,
2536 bool is_method, TRAPS) {
2537 // Nothing to do if loaders are the same.
2538 if (loader1() == loader2()) {
2539 return NULL;
2540 }
2541
2542 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2543 if (ss.is_reference()) {
2544 Symbol* sig = ss.as_symbol();
2545 // Note: In the future, if template-like types can take
2546 // arguments, we will want to recognize them and dig out class
2547 // names hiding inside the argument lists.
2548 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2, THREAD)) {
2549 return sig;
2550 }
2551 }
2552 }
2553 return NULL;
2554 }
2555
2556 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2557 Symbol* signature,
2558 TRAPS) {
2559 methodHandle empty;
2560 assert(MethodHandles::is_signature_polymorphic(iid) &&
2561 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2562 iid != vmIntrinsics::_invokeGeneric,
2563 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2564
2565 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2566 int index = invoke_method_table()->hash_to_index(hash);
2567 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2568 methodHandle m;
2569 if (spe == NULL || spe->method() == NULL) {
2570 spe = NULL;
2571 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2572 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2573 if (!Arguments::is_interpreter_only()) {
2574 // Generate a compiled form of the MH intrinsic.
2575 AdapterHandlerLibrary::create_native_wrapper(m);
2576 // Check if have the compiled code.
2577 if (!m->has_compiled_code()) {
2578 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2579 "Out of space in CodeCache for method handle intrinsic");
2580 }
2581 }
2582 // Now grab the lock. We might have to throw away the new method,
2583 // if a racing thread has managed to install one at the same time.
2584 {
2585 MutexLocker ml(THREAD, SystemDictionary_lock);
2586 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2587 if (spe == NULL)
2588 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2589 if (spe->method() == NULL)
2590 spe->set_method(m());
2591 }
2592 }
2593
2594 assert(spe != NULL && spe->method() != NULL, "");
2595 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2596 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2597 "MH intrinsic invariant");
2598 return spe->method();
2599 }
2600
2601 // Helper for unpacking the return value from linkMethod and linkCallSite.
2602 static Method* unpack_method_and_appendix(Handle mname,
2603 Klass* accessing_klass,
2604 objArrayHandle appendix_box,
2605 Handle* appendix_result,
2606 TRAPS) {
2607 if (mname.not_null()) {
2608 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2609 if (m != NULL) {
2610 oop appendix = appendix_box->obj_at(0);
2611 LogTarget(Info, methodhandles) lt;
2612 if (lt.develop_is_enabled()) {
2613 ResourceMark rm(THREAD);
2614 LogStream ls(lt);
2615 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2616 m->print_on(&ls);
2617 if (appendix != NULL) { ls.print("appendix = "); appendix->print_on(&ls); }
2618 ls.cr();
2619 }
2620
2621 (*appendix_result) = Handle(THREAD, appendix);
2622 // the target is stored in the cpCache and if a reference to this
2623 // MemberName is dropped we need a way to make sure the
2624 // class_loader containing this method is kept alive.
2625 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2626 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2627 this_key->record_dependency(m->method_holder());
2628 return mh();
2629 }
2630 }
2631 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2632 }
2633
2634 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2635 Symbol* name,
2636 Symbol* signature,
2637 Klass* accessing_klass,
2638 Handle *appendix_result,
2639 TRAPS) {
2640 assert(THREAD->can_call_java() ,"");
2641 Handle method_type =
2642 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2643
2644 int ref_kind = JVM_REF_invokeVirtual;
2645 oop name_oop = StringTable::intern(name, CHECK_NULL);
2646 Handle name_str (THREAD, name_oop);
2647 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2648 assert(appendix_box->obj_at(0) == NULL, "");
2649
2650 // This should not happen. JDK code should take care of that.
2651 if (accessing_klass == NULL || method_type.is_null()) {
2652 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2653 }
2654
2655 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2656 JavaCallArguments args;
2657 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2658 args.push_int(ref_kind);
2659 args.push_oop(Handle(THREAD, klass->java_mirror()));
2660 args.push_oop(name_str);
2661 args.push_oop(method_type);
2662 args.push_oop(appendix_box);
2663 JavaValue result(T_OBJECT);
2664 JavaCalls::call_static(&result,
2665 SystemDictionary::MethodHandleNatives_klass(),
2666 vmSymbols::linkMethod_name(),
2667 vmSymbols::linkMethod_signature(),
2668 &args, CHECK_NULL);
2669 Handle mname(THREAD, (oop) result.get_jobject());
2670 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2671 }
2672
2673 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2674 // We must ensure that all class loaders everywhere will reach this class, for any client.
2675 // This is a safe bet for public classes in java.lang, such as Object and String.
2676 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2677 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2678 static bool is_always_visible_class(oop mirror) {
2679 Klass* klass = java_lang_Class::as_Klass(mirror);
2680 if (klass->is_objArray_klass()) {
2681 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2682 }
2683 if (klass->is_typeArray_klass()) {
2684 return true; // primitive array
2685 }
2686 assert(klass->is_instance_klass(), "%s", klass->external_name());
2687 return klass->is_public() &&
2688 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2689 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2690 }
2691
2692 // Find or construct the Java mirror (java.lang.Class instance) for
2693 // the given field type signature, as interpreted relative to the
2694 // given class loader. Handles primitives, void, references, arrays,
2695 // and all other reflectable types, except method types.
2696 // N.B. Code in reflection should use this entry point.
2697 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2698 Klass* accessing_klass,
2699 Handle class_loader,
2700 Handle protection_domain,
2701 SignatureStream::FailureMode failure_mode,
2702 TRAPS) {
2703 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2704 "one or the other, or perhaps neither");
2705
2706 // What we have here must be a valid field descriptor,
2707 // and all valid field descriptors are supported.
2708 // Produce the same java.lang.Class that reflection reports.
2709 if (accessing_klass != NULL) {
2710 class_loader = Handle(THREAD, accessing_klass->class_loader());
2711 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2712 }
2713 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2714 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2715 if (mirror_oop == NULL) {
2716 return Handle(); // report failure this way
2717 }
2718 Handle mirror(THREAD, mirror_oop);
2719
2720 if (accessing_klass != NULL) {
2721 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2722 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2723 if (sel_klass != NULL) {
2724 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2725 }
2726 }
2727 return mirror;
2728 }
2729
2730
2731 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2732 // signature, as interpreted relative to the given class loader.
2733 // Because of class loader constraints, all method handle usage must be
2734 // consistent with this loader.
2735 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2736 Klass* accessing_klass,
2737 TRAPS) {
2738 Handle empty;
2739 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2740 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2741 int index = invoke_method_table()->hash_to_index(hash);
2742 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2743 if (spe != NULL && spe->method_type() != NULL) {
2744 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2745 return Handle(THREAD, spe->method_type());
2746 } else if (!THREAD->can_call_java()) {
2747 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2748 return Handle(); // do not attempt from within compiler, unless it was cached
2749 }
2750
2751 Handle class_loader, protection_domain;
2752 if (accessing_klass != NULL) {
2753 class_loader = Handle(THREAD, accessing_klass->class_loader());
2754 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2755 }
2756 bool can_be_cached = true;
2757 int npts = ArgumentCount(signature).size();
2758 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2759 int arg = 0;
2760 Handle rt; // the return type from the signature
2761 ResourceMark rm(THREAD);
2762 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2763 oop mirror = NULL;
2764 if (can_be_cached) {
2765 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2766 mirror = ss.as_java_mirror(Handle(), Handle(),
2767 SignatureStream::ReturnNull, CHECK_(empty));
2768 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2769 // Fall back to accessing_klass context.
2770 can_be_cached = false;
2771 }
2772 }
2773 if (!can_be_cached) {
2774 // Resolve, throwing a real error if it doesn't work.
2775 mirror = ss.as_java_mirror(class_loader, protection_domain,
2776 SignatureStream::NCDFError, CHECK_(empty));
2777 }
2778 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2779 if (ss.at_return_type())
2780 rt = Handle(THREAD, mirror);
2781 else
2782 pts->obj_at_put(arg++, mirror);
2783
2784 // Check accessibility.
2785 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2786 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2787 mirror = NULL; // safety
2788 // Emulate ConstantPool::verify_constant_pool_resolve.
2789 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2790 }
2791 }
2792 assert(arg == npts, "");
2793
2794 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2795 JavaCallArguments args(Handle(THREAD, rt()));
2796 args.push_oop(pts);
2797 JavaValue result(T_OBJECT);
2798 JavaCalls::call_static(&result,
2799 SystemDictionary::MethodHandleNatives_klass(),
2800 vmSymbols::findMethodHandleType_name(),
2801 vmSymbols::findMethodHandleType_signature(),
2802 &args, CHECK_(empty));
2803 Handle method_type(THREAD, (oop) result.get_jobject());
2804
2805 if (can_be_cached) {
2806 // We can cache this MethodType inside the JVM.
2807 MutexLocker ml(THREAD, SystemDictionary_lock);
2808 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2809 if (spe == NULL)
2810 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2811 if (spe->method_type() == NULL) {
2812 spe->set_method_type(method_type());
2813 }
2814 }
2815
2816 // report back to the caller with the MethodType
2817 return method_type;
2818 }
2819
2820 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2821 Klass* accessing_klass,
2822 TRAPS) {
2823 Handle empty;
2824 ResourceMark rm(THREAD);
2825 SignatureStream ss(signature, /*is_method=*/ false);
2826 if (!ss.is_done()) {
2827 Handle class_loader, protection_domain;
2828 if (accessing_klass != NULL) {
2829 class_loader = Handle(THREAD, accessing_klass->class_loader());
2830 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2831 }
2832 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2833 ss.next();
2834 if (ss.is_done()) {
2835 return Handle(THREAD, mirror);
2836 }
2837 }
2838 return empty;
2839 }
2840
2841 // Ask Java code to find or construct a method handle constant.
2842 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2843 int ref_kind, //e.g., JVM_REF_invokeVirtual
2844 Klass* callee,
2845 Symbol* name,
2846 Symbol* signature,
2847 TRAPS) {
2848 Handle empty;
2849 if (caller == NULL) {
2850 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2851 }
2852 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2853 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2854
2855 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2856 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2857 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2858 java_lang_invoke_MemberName::set_name (mname(), name_str());
2859 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2860 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2861
2862 if (ref_kind == JVM_REF_invokeVirtual &&
2863 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2864 // Skip resolution for public signature polymorphic methods such as
2865 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2866 // They require appendix argument which MemberName resolution doesn't handle.
2867 // There's special logic on JDK side to handle them
2868 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2869 } else {
2870 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2871 }
2872
2873 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2874 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2875
2876 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2877 JavaCallArguments args;
2878 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2879 args.push_int(ref_kind);
2880 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2881 args.push_oop(name_str);
2882 args.push_oop(type);
2883 JavaValue result(T_OBJECT);
2884 JavaCalls::call_static(&result,
2885 SystemDictionary::MethodHandleNatives_klass(),
2886 vmSymbols::linkMethodHandleConstant_name(),
2887 vmSymbols::linkMethodHandleConstant_signature(),
2888 &args, CHECK_(empty));
2889 return Handle(THREAD, (oop) result.get_jobject());
2890 }
2891
2892 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2893 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2894 // with linkage results being stored back into the bootstrap specifier.
2895 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2896 // Resolve the bootstrap specifier, its name, type, and static arguments
2897 bootstrap_specifier.resolve_bsm(CHECK);
2898
2899 // This should not happen. JDK code should take care of that.
2900 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2901 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2902 }
2903
2904 bool is_indy = bootstrap_specifier.is_method_call();
2905 objArrayHandle appendix_box;
2906 if (is_indy) {
2907 // Some method calls may require an appendix argument. Arrange to receive it.
2908 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2909 assert(appendix_box->obj_at(0) == NULL, "");
2910 }
2911
2912 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2913 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2914 JavaCallArguments args;
2915 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2916 args.push_int(bootstrap_specifier.bss_index());
2917 args.push_oop(bootstrap_specifier.bsm());
2918 args.push_oop(bootstrap_specifier.name_arg());
2919 args.push_oop(bootstrap_specifier.type_arg());
2920 args.push_oop(bootstrap_specifier.arg_values());
2921 if (is_indy) {
2922 args.push_oop(appendix_box);
2923 }
2924 JavaValue result(T_OBJECT);
2925 JavaCalls::call_static(&result,
2926 SystemDictionary::MethodHandleNatives_klass(),
2927 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2928 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2929 &args, CHECK);
2930
2931 Handle value(THREAD, (oop) result.get_jobject());
2932 if (is_indy) {
2933 Handle appendix;
2934 Method* method = unpack_method_and_appendix(value,
2935 bootstrap_specifier.caller(),
2936 appendix_box,
2937 &appendix, CHECK);
2938 methodHandle mh(THREAD, method);
2939 bootstrap_specifier.set_resolved_method(mh, appendix);
2940 } else {
2941 bootstrap_specifier.set_resolved_value(value);
2942 }
2943
2944 // sanity check
2945 assert(bootstrap_specifier.is_resolved() ||
2946 (bootstrap_specifier.is_method_call() &&
2947 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2948 }
2949
2950 // Protection domain cache table handling
2951
2952 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2953 return _pd_cache_table->get(protection_domain);
2954 }
2955
2956 // ----------------------------------------------------------------------------
2957
2958 void SystemDictionary::print_on(outputStream *st) {
2959 CDS_ONLY(SystemDictionaryShared::print_on(st));
2960 GCMutexLocker mu(SystemDictionary_lock);
2961
2962 ClassLoaderDataGraph::print_dictionary(st);
2963
2964 // Placeholders
2965 placeholders()->print_on(st);
2966 st->cr();
2967
2968 // loader constraints - print under SD_lock
2969 constraints()->print_on(st);
2970 st->cr();
2971
2972 _pd_cache_table->print_on(st);
2973 st->cr();
2974 }
2975
2976 void SystemDictionary::print() { print_on(tty); }
2977
2978 void SystemDictionary::verify() {
2979 guarantee(constraints() != NULL,
2980 "Verify of loader constraints failed");
2981 guarantee(placeholders()->number_of_entries() >= 0,
2982 "Verify of placeholders failed");
2983
2984 GCMutexLocker mu(SystemDictionary_lock);
2985
2986 // Verify dictionary
2987 ClassLoaderDataGraph::verify_dictionary();
2988
2989 placeholders()->verify();
2990
2991 // Verify constraint table
2992 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2993 constraints()->verify(placeholders());
2994
2995 _pd_cache_table->verify();
2996 }
2997
2998 void SystemDictionary::dump(outputStream *st, bool verbose) {
2999 assert_locked_or_safepoint(SystemDictionary_lock);
3000 if (verbose) {
3001 print_on(st);
3002 } else {
3003 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
3004 ClassLoaderDataGraph::print_table_statistics(st);
3005 placeholders()->print_table_statistics(st, "Placeholder Table");
3006 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3007 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
3008 }
3009 }
3010
3011 TableStatistics SystemDictionary::placeholders_statistics() {
3012 MutexLocker ml(SystemDictionary_lock);
3013 return placeholders()->statistics_calculate();
3014 }
3015
3016 TableStatistics SystemDictionary::loader_constraints_statistics() {
3017 MutexLocker ml(SystemDictionary_lock);
3018 return constraints()->statistics_calculate();
3019 }
3020
3021 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
3022 MutexLocker ml(SystemDictionary_lock);
3023 return pd_cache_table()->statistics_calculate();
3024 }
3025
3026 // Utility for dumping dictionaries.
3027 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3028 DCmdWithParser(output, heap),
3029 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3030 "BOOLEAN", false, "false") {
3031 _dcmdparser.add_dcmd_option(&_verbose);
3032 }
3033
3034 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3035 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3036 _verbose.value());
3037 VMThread::execute(&dumper);
3038 }
3039
3040 int SystemDictionaryDCmd::num_arguments() {
3041 ResourceMark rm;
3042 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3043 if (dcmd != NULL) {
3044 DCmdMark mark(dcmd);
3045 return dcmd->_dcmdparser.num_arguments();
3046 } else {
3047 return 0;
3048 }
3049 }