1 /*
2 * Copyright (c) 1997, 2014, 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 "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "interpreter/bytecodeStream.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/gcLocker.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/methodData.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "oops/typeArrayKlass.hpp"
47 #include "prims/jvmtiEnvBase.hpp"
48 #include "prims/methodHandles.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fieldType.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/signature.hpp"
56 #include "services/classLoadingService.hpp"
57 #include "services/threadService.hpp"
58 #include "utilities/macros.hpp"
59 #include "utilities/ticks.hpp"
60
61 #if INCLUDE_TRACE
62 #include "trace/tracing.hpp"
63 #endif
64
65 Dictionary* SystemDictionary::_dictionary = NULL;
66 PlaceholderTable* SystemDictionary::_placeholders = NULL;
67 Dictionary* SystemDictionary::_shared_dictionary = NULL;
68 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
69 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
70 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
71
72
73 int SystemDictionary::_number_of_modifications = 0;
74 int SystemDictionary::_sdgeneration = 0;
75 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
76 20201,40423,99991};
77
78 oop SystemDictionary::_system_loader_lock_obj = NULL;
79
80 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
81 = { NULL /*, NULL...*/ };
82
83 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
84
85 oop SystemDictionary::_java_system_loader = NULL;
86
87 bool SystemDictionary::_has_loadClassInternal = false;
88 bool SystemDictionary::_has_checkPackageAccess = false;
89
90 // lazily initialized klass variables
91 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
92
93
94 // ----------------------------------------------------------------------------
95 // Java-level SystemLoader
96
97 oop SystemDictionary::java_system_loader() {
98 return _java_system_loader;
99 }
100
101 void SystemDictionary::compute_java_system_loader(TRAPS) {
102 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
103 JavaValue result(T_OBJECT);
104 JavaCalls::call_static(&result,
105 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
106 vmSymbols::getSystemClassLoader_name(),
107 vmSymbols::void_classloader_signature(),
108 CHECK);
109
110 _java_system_loader = (oop)result.get_jobject();
111 }
112
113
114 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
115 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
116 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
117 }
118
119 // ----------------------------------------------------------------------------
120 // debugging
121
122 #ifdef ASSERT
123
124 // return true if class_name contains no '.' (internal format is '/')
125 bool SystemDictionary::is_internal_format(Symbol* class_name) {
126 if (class_name != NULL) {
127 ResourceMark rm;
128 char* name = class_name->as_C_string();
129 return strchr(name, '.') == NULL;
130 } else {
131 return true;
132 }
133 }
134
135 #endif
136
137 // ----------------------------------------------------------------------------
138 // Parallel class loading check
139
140 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
141 if (UnsyncloadClass || class_loader.is_null()) return true;
142 if (AlwaysLockClassLoader) return false;
143 return java_lang_ClassLoader::parallelCapable(class_loader());
144 }
145 // ----------------------------------------------------------------------------
146 // ParallelDefineClass flag does not apply to bootclass loader
147 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
148 if (class_loader.is_null()) return false;
149 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
150 return true;
151 }
152 return false;
153 }
154
155 /**
156 * Returns true if the passed class loader is the extension class loader.
157 */
158 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
159 if (class_loader.is_null()) {
160 return false;
161 }
162 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
163 }
164
165 // ----------------------------------------------------------------------------
166 // Resolving of classes
167
168 // Forwards to resolve_or_null
169
170 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
171 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
172 if (HAS_PENDING_EXCEPTION || klass == NULL) {
173 KlassHandle k_h(THREAD, klass);
174 // can return a null klass
175 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
176 }
177 return klass;
178 }
179
180 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
181 if (HAS_PENDING_EXCEPTION) {
182 // If we have a pending exception we forward it to the caller, unless throw_error is true,
183 // in which case we have to check whether the pending exception is a ClassNotFoundException,
184 // and if so convert it to a NoClassDefFoundError
185 // And chain the original ClassNotFoundException
186 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
187 ResourceMark rm(THREAD);
188 assert(klass_h() == NULL, "Should not have result with exception pending");
189 Handle e(THREAD, PENDING_EXCEPTION);
190 CLEAR_PENDING_EXCEPTION;
191 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
192 } else {
193 return NULL;
194 }
195 }
196 // Class not found, throw appropriate error or exception depending on value of throw_error
197 if (klass_h() == NULL) {
198 ResourceMark rm(THREAD);
199 if (throw_error) {
200 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
201 } else {
202 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
203 }
204 }
205 return (Klass*)klass_h();
206 }
207
208
209 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
210 bool throw_error, TRAPS)
211 {
212 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
213 }
214
215
216 // Forwards to resolve_instance_class_or_null
217
218 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
219 assert(!THREAD->is_Compiler_thread(),
220 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
221 class_name->as_C_string(),
222 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
223 if (FieldType::is_array(class_name)) {
224 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
225 } else if (FieldType::is_obj(class_name)) {
226 ResourceMark rm(THREAD);
227 // Ignore wrapping L and ;.
228 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
229 class_name->utf8_length() - 2, CHECK_NULL);
230 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
231 } else {
232 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
233 }
234 }
235
236 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
237 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
238 }
239
240 // Forwards to resolve_instance_class_or_null
241
242 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
243 Handle class_loader,
244 Handle protection_domain,
245 TRAPS) {
246 assert(FieldType::is_array(class_name), "must be array");
247 Klass* k = NULL;
248 FieldArrayInfo fd;
249 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
250 // of this call
251 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
252 if (t == T_OBJECT) {
253 // naked oop "k" is OK here -- we assign back into it
254 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
255 class_loader,
256 protection_domain,
257 CHECK_NULL);
258 if (k != NULL) {
259 k = k->array_klass(fd.dimension(), CHECK_NULL);
260 }
261 } else {
262 k = Universe::typeArrayKlassObj(t);
263 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
264 }
265 return k;
266 }
267
268
269 // Must be called for any super-class or super-interface resolution
270 // during class definition to allow class circularity checking
271 // super-interface callers:
272 // parse_interfaces - for defineClass & jvmtiRedefineClasses
273 // super-class callers:
274 // ClassFileParser - for defineClass & jvmtiRedefineClasses
275 // load_shared_class - while loading a class from shared archive
276 // resolve_instance_class_or_null:
277 // via: handle_parallel_super_load
278 // when resolving a class that has an existing placeholder with
279 // a saved superclass [i.e. a defineClass is currently in progress]
280 // if another thread is trying to resolve the class, it must do
281 // super-class checks on its own thread to catch class circularity
282 // This last call is critical in class circularity checking for cases
283 // where classloading is delegated to different threads and the
284 // classloader lock is released.
285 // Take the case: Base->Super->Base
286 // 1. If thread T1 tries to do a defineClass of class Base
287 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
288 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
289 // so it tries to load Super
290 // 3. If we load the class internally, or user classloader uses same thread
291 // loadClassFromxxx or defineClass via parseClassFile Super ...
292 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
293 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
294 // 3.4 calls resolve_super_or_fail Base
295 // 3.5 finds T1,Base -> throws class circularity
296 //OR 4. If T2 tries to resolve Super via defineClass Super ...
297 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
298 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
299 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
300 // 4.4 finds T2, Super -> throws class circularity
301 // Must be called, even if superclass is null, since this is
302 // where the placeholder entry is created which claims this
303 // thread is loading this class/classloader.
304 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
305 Symbol* class_name,
306 Handle class_loader,
307 Handle protection_domain,
308 bool is_superclass,
309 TRAPS) {
310 // Double-check, if child class is already loaded, just return super-class,interface
311 // Don't add a placedholder if already loaded, i.e. already in system dictionary
312 // Make sure there's a placeholder for the *child* before resolving.
313 // Used as a claim that this thread is currently loading superclass/classloader
314 // Used here for ClassCircularity checks and also for heap verification
315 // (every InstanceKlass in the heap needs to be in the system dictionary
316 // or have a placeholder).
317 // Must check ClassCircularity before checking if super class is already loaded
318 //
319 // We might not already have a placeholder if this child_name was
320 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
321 // the name of the class might not be known until the stream is actually
322 // parsed.
323 // Bugs 4643874, 4715493
324 // compute_hash can have a safepoint
325
326 ClassLoaderData* loader_data = class_loader_data(class_loader);
327 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
328 int d_index = dictionary()->hash_to_index(d_hash);
329 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
330 int p_index = placeholders()->hash_to_index(p_hash);
331 // can't throw error holding a lock
332 bool child_already_loaded = false;
333 bool throw_circularity_error = false;
334 {
335 MutexLocker mu(SystemDictionary_lock, THREAD);
336 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
337 Klass* quicksuperk;
338 // to support // loading: if child done loading, just return superclass
339 // if class_name, & class_loader don't match:
340 // if initial define, SD update will give LinkageError
341 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
342 // so we don't throw an exception here.
343 // see: nsk redefclass014 & java.lang.instrument Instrument032
344 if ((childk != NULL ) && (is_superclass) &&
345 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
346
347 ((quicksuperk->name() == class_name) &&
348 (quicksuperk->class_loader() == class_loader()))) {
349 return quicksuperk;
350 } else {
351 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
352 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
353 throw_circularity_error = true;
354 }
355 }
356 if (!throw_circularity_error) {
357 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
358 }
359 }
360 if (throw_circularity_error) {
361 ResourceMark rm(THREAD);
362 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
363 }
364
365 // java.lang.Object should have been found above
366 assert(class_name != NULL, "null super class for resolving");
367 // Resolve the super class or interface, check results on return
368 Klass* superk = SystemDictionary::resolve_or_null(class_name,
369 class_loader,
370 protection_domain,
371 THREAD);
372
373 KlassHandle superk_h(THREAD, superk);
374
375 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
376 // It is no longer necessary to keep the placeholder table alive until update_dictionary
377 // or error. GC used to walk the placeholder table as strong roots.
378 // The instanceKlass is kept alive because the class loader is on the stack,
379 // which keeps the loader_data alive, as well as all instanceKlasses in
380 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
381 {
382 MutexLocker mu(SystemDictionary_lock, THREAD);
383 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
384 SystemDictionary_lock->notify_all();
385 }
386 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
387 // can null superk
388 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
389 }
390
391 return superk_h();
392 }
393
394 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
395 Handle class_loader,
396 Handle protection_domain,
397 TRAPS) {
398 if(!has_checkPackageAccess()) return;
399
400 // Now we have to call back to java to check if the initating class has access
401 JavaValue result(T_VOID);
402 if (TraceProtectionDomainVerification) {
403 // Print out trace information
404 tty->print_cr("Checking package access");
405 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
406 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
407 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
408 }
409
410 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
411 JavaCalls::call_special(&result,
412 class_loader,
413 system_loader,
414 vmSymbols::checkPackageAccess_name(),
415 vmSymbols::class_protectiondomain_signature(),
416 Handle(THREAD, klass->java_mirror()),
417 protection_domain,
418 THREAD);
419
420 if (TraceProtectionDomainVerification) {
421 if (HAS_PENDING_EXCEPTION) {
422 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
423 } else {
424 tty->print_cr(" -> granted");
425 }
426 tty->cr();
427 }
428
429 if (HAS_PENDING_EXCEPTION) return;
430
431 // If no exception has been thrown, we have validated the protection domain
432 // Insert the protection domain of the initiating class into the set.
433 {
434 // We recalculate the entry here -- we've called out to java since
435 // the last time it was calculated.
436 ClassLoaderData* loader_data = class_loader_data(class_loader);
437
438 Symbol* kn = klass->name();
439 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
440 int d_index = dictionary()->hash_to_index(d_hash);
441
442 MutexLocker mu(SystemDictionary_lock, THREAD);
443 {
444 // Note that we have an entry, and entries can be deleted only during GC,
445 // so we cannot allow GC to occur while we're holding this entry.
446
447 // We're using a No_Safepoint_Verifier to catch any place where we
448 // might potentially do a GC at all.
449 // Dictionary::do_unloading() asserts that classes in SD are only
450 // unloaded at a safepoint. Anonymous classes are not in SD.
451 No_Safepoint_Verifier nosafepoint;
452 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
453 protection_domain, THREAD);
454 }
455 }
456 }
457
458 // We only get here if this thread finds that another thread
459 // has already claimed the placeholder token for the current operation,
460 // but that other thread either never owned or gave up the
461 // object lock
462 // Waits on SystemDictionary_lock to indicate placeholder table updated
463 // On return, caller must recheck placeholder table state
464 //
465 // We only get here if
466 // 1) custom classLoader, i.e. not bootstrap classloader
467 // 2) UnsyncloadClass not set
468 // 3) custom classLoader has broken the class loader objectLock
469 // so another thread got here in parallel
470 //
471 // lockObject must be held.
472 // Complicated dance due to lock ordering:
473 // Must first release the classloader object lock to
474 // allow initial definer to complete the class definition
475 // and to avoid deadlock
476 // Reclaim classloader lock object with same original recursion count
477 // Must release SystemDictionary_lock after notify, since
478 // class loader lock must be claimed before SystemDictionary_lock
479 // to prevent deadlocks
480 //
481 // The notify allows applications that did an untimed wait() on
482 // the classloader object lock to not hang.
483 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
484 assert_lock_strong(SystemDictionary_lock);
485
486 bool calledholdinglock
487 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
488 assert(calledholdinglock,"must hold lock for notify");
489 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
490 ObjectSynchronizer::notifyall(lockObject, THREAD);
491 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
492 SystemDictionary_lock->wait();
493 SystemDictionary_lock->unlock();
494 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
495 SystemDictionary_lock->lock();
496 }
497
498 // If the class in is in the placeholder table, class loading is in progress
499 // For cases where the application changes threads to load classes, it
500 // is critical to ClassCircularity detection that we try loading
501 // the superclass on the same thread internally, so we do parallel
502 // super class loading here.
503 // This also is critical in cases where the original thread gets stalled
504 // even in non-circularity situations.
505 // Note: must call resolve_super_or_fail even if null super -
506 // to force placeholder entry creation for this class for circularity detection
507 // Caller must check for pending exception
508 // Returns non-null Klass* if other thread has completed load
509 // and we are done,
510 // If return null Klass* and no pending exception, the caller must load the class
511 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
512 Symbol* name, Symbol* superclassname, Handle class_loader,
513 Handle protection_domain, Handle lockObject, TRAPS) {
514
515 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
516 ClassLoaderData* loader_data = class_loader_data(class_loader);
517 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
518 int d_index = dictionary()->hash_to_index(d_hash);
519 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
520 int p_index = placeholders()->hash_to_index(p_hash);
521
522 // superk is not used, resolve_super called for circularity check only
523 // This code is reached in two situations. One if this thread
524 // is loading the same class twice (e.g. ClassCircularity, or
525 // java.lang.instrument).
526 // The second is if another thread started the resolve_super first
527 // and has not yet finished.
528 // In both cases the original caller will clean up the placeholder
529 // entry on error.
530 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
531 superclassname,
532 class_loader,
533 protection_domain,
534 true,
535 CHECK_(nh));
536
537 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
538 // Serial class loaders and bootstrap classloader do wait for superclass loads
539 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
540 MutexLocker mu(SystemDictionary_lock, THREAD);
541 // Check if classloading completed while we were loading superclass or waiting
542 Klass* check = find_class(d_index, d_hash, name, loader_data);
543 if (check != NULL) {
544 // Klass is already loaded, so just return it
545 return(instanceKlassHandle(THREAD, check));
546 } else {
547 return nh;
548 }
549 }
550
551 // must loop to both handle other placeholder updates
552 // and spurious notifications
553 bool super_load_in_progress = true;
554 PlaceholderEntry* placeholder;
555 while (super_load_in_progress) {
556 MutexLocker mu(SystemDictionary_lock, THREAD);
557 // Check if classloading completed while we were loading superclass or waiting
558 Klass* check = find_class(d_index, d_hash, name, loader_data);
559 if (check != NULL) {
560 // Klass is already loaded, so just return it
561 return(instanceKlassHandle(THREAD, check));
562 } else {
563 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
564 if (placeholder && placeholder->super_load_in_progress() ){
565 // Before UnsyncloadClass:
566 // We only get here if the application has released the
567 // classloader lock when another thread was in the middle of loading a
568 // superclass/superinterface for this class, and now
569 // this thread is also trying to load this class.
570 // To minimize surprises, the first thread that started to
571 // load a class should be the one to complete the loading
572 // with the classfile it initially expected.
573 // This logic has the current thread wait once it has done
574 // all the superclass/superinterface loading it can, until
575 // the original thread completes the class loading or fails
576 // If it completes we will use the resulting InstanceKlass
577 // which we will find below in the systemDictionary.
578 // We also get here for parallel bootstrap classloader
579 if (class_loader.is_null()) {
580 SystemDictionary_lock->wait();
581 } else {
582 double_lock_wait(lockObject, THREAD);
583 }
584 } else {
585 // If not in SD and not in PH, other thread's load must have failed
586 super_load_in_progress = false;
587 }
588 }
589 }
590 return (nh);
591 }
592
593
594 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
595 Handle class_loader,
596 Handle protection_domain,
597 TRAPS) {
598 assert(name != NULL && !FieldType::is_array(name) &&
599 !FieldType::is_obj(name), "invalid class name");
600
601 Ticks class_load_start_time = Ticks::now();
602
603 // UseNewReflection
604 // Fix for 4474172; see evaluation for more details
605 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
606 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
607
608 // Do lookup to see if class already exist and the protection domain
609 // has the right access
610 // This call uses find which checks protection domain already matches
611 // All subsequent calls use find_class, and set has_loaded_class so that
612 // before we return a result we call out to java to check for valid protection domain
613 // to allow returning the Klass* and add it to the pd_set if it is valid
614 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
615 int d_index = dictionary()->hash_to_index(d_hash);
616 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
617 protection_domain, THREAD);
618 if (probe != NULL) return probe;
619
620
621 // Non-bootstrap class loaders will call out to class loader and
622 // define via jvm/jni_DefineClass which will acquire the
623 // class loader object lock to protect against multiple threads
624 // defining the class in parallel by accident.
625 // This lock must be acquired here so the waiter will find
626 // any successful result in the SystemDictionary and not attempt
627 // the define
628 // ParallelCapable Classloaders and the bootstrap classloader,
629 // or all classloaders with UnsyncloadClass do not acquire lock here
630 bool DoObjectLock = true;
631 if (is_parallelCapable(class_loader)) {
632 DoObjectLock = false;
633 }
634
635 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
636 int p_index = placeholders()->hash_to_index(p_hash);
637
638 // Class is not in SystemDictionary so we have to do loading.
639 // Make sure we are synchronized on the class loader before we proceed
640 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
641 check_loader_lock_contention(lockObject, THREAD);
642 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
643
644 // Check again (after locking) if class already exist in SystemDictionary
645 bool class_has_been_loaded = false;
646 bool super_load_in_progress = false;
647 bool havesupername = false;
648 instanceKlassHandle k;
649 PlaceholderEntry* placeholder;
650 Symbol* superclassname = NULL;
651
652 {
653 MutexLocker mu(SystemDictionary_lock, THREAD);
654 Klass* check = find_class(d_index, d_hash, name, loader_data);
655 if (check != NULL) {
656 // Klass is already loaded, so just return it
657 class_has_been_loaded = true;
658 k = instanceKlassHandle(THREAD, check);
659 } else {
660 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
661 if (placeholder && placeholder->super_load_in_progress()) {
662 super_load_in_progress = true;
663 if (placeholder->havesupername() == true) {
664 superclassname = placeholder->supername();
665 havesupername = true;
666 }
667 }
668 }
669 }
670
671 // If the class is in the placeholder table, class loading is in progress
672 if (super_load_in_progress && havesupername==true) {
673 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
674 class_loader, protection_domain, lockObject, THREAD);
675 if (HAS_PENDING_EXCEPTION) {
676 return NULL;
677 }
678 if (!k.is_null()) {
679 class_has_been_loaded = true;
680 }
681 }
682
683 bool throw_circularity_error = false;
684 if (!class_has_been_loaded) {
685 bool load_instance_added = false;
686
687 // add placeholder entry to record loading instance class
688 // Five cases:
689 // All cases need to prevent modifying bootclasssearchpath
690 // in parallel with a classload of same classname
691 // Redefineclasses uses existence of the placeholder for the duration
692 // of the class load to prevent concurrent redefinition of not completely
693 // defined classes.
694 // case 1. traditional classloaders that rely on the classloader object lock
695 // - no other need for LOAD_INSTANCE
696 // case 2. traditional classloaders that break the classloader object lock
697 // as a deadlock workaround. Detection of this case requires that
698 // this check is done while holding the classloader object lock,
699 // and that lock is still held when calling classloader's loadClass.
700 // For these classloaders, we ensure that the first requestor
701 // completes the load and other requestors wait for completion.
702 // case 3. UnsyncloadClass - don't use objectLocker
703 // With this flag, we allow parallel classloading of a
704 // class/classloader pair
705 // case4. Bootstrap classloader - don't own objectLocker
706 // This classloader supports parallelism at the classloader level,
707 // but only allows a single load of a class/classloader pair.
708 // No performance benefit and no deadlock issues.
709 // case 5. parallelCapable user level classloaders - without objectLocker
710 // Allow parallel classloading of a class/classloader pair
711
712 {
713 MutexLocker mu(SystemDictionary_lock, THREAD);
714 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
715 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
716 if (oldprobe) {
717 // only need check_seen_thread once, not on each loop
718 // 6341374 java/lang/Instrument with -Xcomp
719 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
720 throw_circularity_error = true;
721 } else {
722 // case 1: traditional: should never see load_in_progress.
723 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
724
725 // case 4: bootstrap classloader: prevent futile classloading,
726 // wait on first requestor
727 if (class_loader.is_null()) {
728 SystemDictionary_lock->wait();
729 } else {
730 // case 2: traditional with broken classloader lock. wait on first
731 // requestor.
732 double_lock_wait(lockObject, THREAD);
733 }
734 // Check if classloading completed while we were waiting
735 Klass* check = find_class(d_index, d_hash, name, loader_data);
736 if (check != NULL) {
737 // Klass is already loaded, so just return it
738 k = instanceKlassHandle(THREAD, check);
739 class_has_been_loaded = true;
740 }
741 // check if other thread failed to load and cleaned up
742 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
743 }
744 }
745 }
746 }
747 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
748 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
749 // LOAD_INSTANCE in parallel
750
751 if (!throw_circularity_error && !class_has_been_loaded) {
752 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
753 load_instance_added = true;
754 // For class loaders that do not acquire the classloader object lock,
755 // if they did not catch another thread holding LOAD_INSTANCE,
756 // need a check analogous to the acquire ObjectLocker/find_class
757 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
758 // one final check if the load has already completed
759 // class loaders holding the ObjectLock shouldn't find the class here
760 Klass* check = find_class(d_index, d_hash, name, loader_data);
761 if (check != NULL) {
762 // Klass is already loaded, so return it after checking/adding protection domain
763 k = instanceKlassHandle(THREAD, check);
764 class_has_been_loaded = true;
765 }
766 }
767 }
768
769 // must throw error outside of owning lock
770 if (throw_circularity_error) {
771 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
772 ResourceMark rm(THREAD);
773 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
774 }
775
776 if (!class_has_been_loaded) {
777
778 // Do actual loading
779 k = load_instance_class(name, class_loader, THREAD);
780
781 // For UnsyncloadClass only
782 // If they got a linkageError, check if a parallel class load succeeded.
783 // If it did, then for bytecode resolution the specification requires
784 // that we return the same result we did for the other thread, i.e. the
785 // successfully loaded InstanceKlass
786 // Should not get here for classloaders that support parallelism
787 // with the new cleaner mechanism, even with AllowParallelDefineClass
788 // Bootstrap goes through here to allow for an extra guarantee check
789 if (UnsyncloadClass || (class_loader.is_null())) {
790 if (k.is_null() && HAS_PENDING_EXCEPTION
791 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
792 MutexLocker mu(SystemDictionary_lock, THREAD);
793 Klass* check = find_class(d_index, d_hash, name, loader_data);
794 if (check != NULL) {
795 // Klass is already loaded, so just use it
796 k = instanceKlassHandle(THREAD, check);
797 CLEAR_PENDING_EXCEPTION;
798 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
799 }
800 }
801 }
802
803 // If everything was OK (no exceptions, no null return value), and
804 // class_loader is NOT the defining loader, do a little more bookkeeping.
805 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
806 k->class_loader() != class_loader()) {
807
808 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
809
810 // Need to check for a PENDING_EXCEPTION again; check_constraints
811 // can throw and doesn't use the CHECK macro.
812 if (!HAS_PENDING_EXCEPTION) {
813 { // Grabbing the Compile_lock prevents systemDictionary updates
814 // during compilations.
815 MutexLocker mu(Compile_lock, THREAD);
816 update_dictionary(d_index, d_hash, p_index, p_hash,
817 k, class_loader, THREAD);
818 }
819
820 if (JvmtiExport::should_post_class_load()) {
821 Thread *thread = THREAD;
822 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
823 JvmtiExport::post_class_load((JavaThread *) thread, k());
824 }
825 }
826 }
827 } // load_instance_class loop
828
829 if (load_instance_added == true) {
830 // clean up placeholder entries for LOAD_INSTANCE success or error
831 // This brackets the SystemDictionary updates for both defining
832 // and initiating loaders
833 MutexLocker mu(SystemDictionary_lock, THREAD);
834 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
835 SystemDictionary_lock->notify_all();
836 }
837 }
838
839 if (HAS_PENDING_EXCEPTION || k.is_null()) {
840 return NULL;
841 }
842
843 post_class_load_event(class_load_start_time, k, class_loader);
844
845 #ifdef ASSERT
846 {
847 ClassLoaderData* loader_data = k->class_loader_data();
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 Klass* kk = find_class(name, loader_data);
850 assert(kk == k(), "should be present in dictionary");
851 }
852 #endif
853
854 // return if the protection domain in NULL
855 if (protection_domain() == NULL) return k();
856
857 // Check the protection domain has the right access
858 {
859 MutexLocker mu(SystemDictionary_lock, THREAD);
860 // Note that we have an entry, and entries can be deleted only during GC,
861 // so we cannot allow GC to occur while we're holding this entry.
862 // We're using a No_Safepoint_Verifier to catch any place where we
863 // might potentially do a GC at all.
864 // Dictionary::do_unloading() asserts that classes in SD are only
865 // unloaded at a safepoint. Anonymous classes are not in SD.
866 No_Safepoint_Verifier nosafepoint;
867 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
868 loader_data,
869 protection_domain)) {
870 return k();
871 }
872 }
873
874 // Verify protection domain. If it fails an exception is thrown
875 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
876
877 return k();
878 }
879
880
881 // This routine does not lock the system dictionary.
882 //
883 // Since readers don't hold a lock, we must make sure that system
884 // dictionary entries are only removed at a safepoint (when only one
885 // thread is running), and are added to in a safe way (all links must
886 // be updated in an MT-safe manner).
887 //
888 // Callers should be aware that an entry could be added just after
889 // _dictionary->bucket(index) is read here, so the caller will not see
890 // the new entry.
891
892 Klass* SystemDictionary::find(Symbol* class_name,
893 Handle class_loader,
894 Handle protection_domain,
895 TRAPS) {
896
897 // UseNewReflection
898 // The result of this call should be consistent with the result
899 // of the call to resolve_instance_class_or_null().
900 // See evaluation 6790209 and 4474172 for more details.
901 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
902 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
903
904 if (loader_data == NULL) {
905 // If the ClassLoaderData has not been setup,
906 // then the class loader has no entries in the dictionary.
907 return NULL;
908 }
909
910 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
911 int d_index = dictionary()->hash_to_index(d_hash);
912
913 {
914 // Note that we have an entry, and entries can be deleted only during GC,
915 // so we cannot allow GC to occur while we're holding this entry.
916 // We're using a No_Safepoint_Verifier to catch any place where we
917 // might potentially do a GC at all.
918 // Dictionary::do_unloading() asserts that classes in SD are only
919 // unloaded at a safepoint. Anonymous classes are not in SD.
920 No_Safepoint_Verifier nosafepoint;
921 return dictionary()->find(d_index, d_hash, class_name, loader_data,
922 protection_domain, THREAD);
923 }
924 }
925
926
927 // Look for a loaded instance or array klass by name. Do not do any loading.
928 // return NULL in case of error.
929 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
930 Handle class_loader,
931 Handle protection_domain,
932 TRAPS) {
933 Klass* k = NULL;
934 assert(class_name != NULL, "class name must be non NULL");
935
936 if (FieldType::is_array(class_name)) {
937 // The name refers to an array. Parse the name.
938 // dimension and object_key in FieldArrayInfo are assigned as a
939 // side-effect of this call
940 FieldArrayInfo fd;
941 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
942 if (t != T_OBJECT) {
943 k = Universe::typeArrayKlassObj(t);
944 } else {
945 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
946 }
947 if (k != NULL) {
948 k = k->array_klass_or_null(fd.dimension());
949 }
950 } else {
951 k = find(class_name, class_loader, protection_domain, THREAD);
952 }
953 return k;
954 }
955
956 // Note: this method is much like resolve_from_stream, but
957 // updates no supplemental data structures.
958 // TODO consolidate the two methods with a helper routine?
959 Klass* SystemDictionary::parse_stream(Symbol* class_name,
960 Handle class_loader,
961 Handle protection_domain,
962 ClassFileStream* st,
963 KlassHandle host_klass,
964 GrowableArray<Handle>* cp_patches,
965 TRAPS) {
966 TempNewSymbol parsed_name = NULL;
967
968 Ticks class_load_start_time = Ticks::now();
969
970 ClassLoaderData* loader_data;
971 if (host_klass.not_null()) {
972 // Create a new CLD for anonymous class, that uses the same class loader
973 // as the host_klass
974 assert(EnableInvokeDynamic, "");
975 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
976 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
977 loader_data->record_dependency(host_klass(), CHECK_NULL);
978 } else {
979 loader_data = ClassLoaderData::class_loader_data(class_loader());
980 }
981
982 // Parse the stream. Note that we do this even though this klass might
983 // already be present in the SystemDictionary, otherwise we would not
984 // throw potential ClassFormatErrors.
985 //
986 // Note: "name" is updated.
987
988 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
989 loader_data,
990 protection_domain,
991 host_klass,
992 cp_patches,
993 parsed_name,
994 true,
995 THREAD);
996
997
998 if (host_klass.not_null() && k.not_null()) {
999 assert(EnableInvokeDynamic, "");
1000 k->set_host_klass(host_klass());
1001 // If it's anonymous, initialize it now, since nobody else will.
1002
1003 {
1004 MutexLocker mu_r(Compile_lock, THREAD);
1005
1006 // Add to class hierarchy, initialize vtables, and do possible
1007 // deoptimizations.
1008 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1009
1010 // But, do not add to system dictionary.
1011
1012 // compiled code dependencies need to be validated anyway
1013 notice_modification();
1014 }
1015
1016 // Rewrite and patch constant pool here.
1017 k->link_class(CHECK_NULL);
1018 if (cp_patches != NULL) {
1019 k->constants()->patch_resolved_references(cp_patches);
1020 }
1021 k->eager_initialize(CHECK_NULL);
1022
1023 // notify jvmti
1024 if (JvmtiExport::should_post_class_load()) {
1025 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1026 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1027 }
1028
1029 post_class_load_event(class_load_start_time, k, class_loader);
1030 }
1031 assert(host_klass.not_null() || cp_patches == NULL,
1032 "cp_patches only found with host_klass");
1033
1034 return k();
1035 }
1036
1037 // Add a klass to the system from a stream (called by jni_DefineClass and
1038 // JVM_DefineClass).
1039 // Note: class_name can be NULL. In that case we do not know the name of
1040 // the class until we have parsed the stream.
1041
1042 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1043 Handle class_loader,
1044 Handle protection_domain,
1045 ClassFileStream* st,
1046 bool verify,
1047 TRAPS) {
1048
1049 // Classloaders that support parallelism, e.g. bootstrap classloader,
1050 // or all classloaders with UnsyncloadClass do not acquire lock here
1051 bool DoObjectLock = true;
1052 if (is_parallelCapable(class_loader)) {
1053 DoObjectLock = false;
1054 }
1055
1056 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1057
1058 // Make sure we are synchronized on the class loader before we proceed
1059 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1060 check_loader_lock_contention(lockObject, THREAD);
1061 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1062
1063 TempNewSymbol parsed_name = NULL;
1064
1065 // Parse the stream. Note that we do this even though this klass might
1066 // already be present in the SystemDictionary, otherwise we would not
1067 // throw potential ClassFormatErrors.
1068 //
1069 // Note: "name" is updated.
1070
1071 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1072 loader_data,
1073 protection_domain,
1074 parsed_name,
1075 verify,
1076 THREAD);
1077
1078 const char* pkg = "java/";
1079 if (!HAS_PENDING_EXCEPTION &&
1080 !class_loader.is_null() &&
1081 parsed_name != NULL &&
1082 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1083 // It is illegal to define classes in the "java." package from
1084 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1085 ResourceMark rm(THREAD);
1086 char* name = parsed_name->as_C_string();
1087 char* index = strrchr(name, '/');
1088 *index = '\0'; // chop to just the package name
1089 while ((index = strchr(name, '/')) != NULL) {
1090 *index = '.'; // replace '/' with '.' in package name
1091 }
1092 const char* fmt = "Prohibited package name: %s";
1093 size_t len = strlen(fmt) + strlen(name);
1094 char* message = NEW_RESOURCE_ARRAY(char, len);
1095 jio_snprintf(message, len, fmt, name);
1096 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1097 vmSymbols::java_lang_SecurityException(), message);
1098 }
1099
1100 if (!HAS_PENDING_EXCEPTION) {
1101 assert(parsed_name != NULL, "Sanity");
1102 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1103 // Verification prevents us from creating names with dots in them, this
1104 // asserts that that's the case.
1105 assert(is_internal_format(parsed_name),
1106 "external class name format used internally");
1107
1108 // Add class just loaded
1109 // If a class loader supports parallel classloading handle parallel define requests
1110 // find_or_define_instance_class may return a different InstanceKlass
1111 if (is_parallelCapable(class_loader)) {
1112 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1113 } else {
1114 define_instance_class(k, THREAD);
1115 }
1116 }
1117
1118 // Make sure we have an entry in the SystemDictionary on success
1119 debug_only( {
1120 if (!HAS_PENDING_EXCEPTION) {
1121 assert(parsed_name != NULL, "parsed_name is still null?");
1122 Symbol* h_name = k->name();
1123 ClassLoaderData *defining_loader_data = k->class_loader_data();
1124
1125 MutexLocker mu(SystemDictionary_lock, THREAD);
1126
1127 Klass* check = find_class(parsed_name, loader_data);
1128 assert(check == k(), "should be present in the dictionary");
1129
1130 Klass* check2 = find_class(h_name, defining_loader_data);
1131 assert(check == check2, "name inconsistancy in SystemDictionary");
1132 }
1133 } );
1134
1135 return k();
1136 }
1137
1138
1139 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1140 int number_of_entries) {
1141 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1142 "bad shared dictionary size.");
1143 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1144 }
1145
1146
1147 // If there is a shared dictionary, then find the entry for the
1148 // given shared system class, if any.
1149
1150 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1151 if (shared_dictionary() != NULL) {
1152 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1153 int d_index = shared_dictionary()->hash_to_index(d_hash);
1154
1155 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1156 } else {
1157 return NULL;
1158 }
1159 }
1160
1161
1162 // Load a class from the shared spaces (found through the shared system
1163 // dictionary). Force the superclass and all interfaces to be loaded.
1164 // Update the class definition to include sibling classes and no
1165 // subclasses (yet). [Classes in the shared space are not part of the
1166 // object hierarchy until loaded.]
1167
1168 instanceKlassHandle SystemDictionary::load_shared_class(
1169 Symbol* class_name, Handle class_loader, TRAPS) {
1170 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1171 return load_shared_class(ik, class_loader, THREAD);
1172 }
1173
1174 instanceKlassHandle SystemDictionary::load_shared_class(
1175 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1176 assert(class_loader.is_null(), "non-null classloader for shared class?");
1177 if (ik.not_null()) {
1178 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1179 Symbol* class_name = ik->name();
1180
1181 // Found the class, now load the superclass and interfaces. If they
1182 // are shared, add them to the main system dictionary and reset
1183 // their hierarchy references (supers, subs, and interfaces).
1184
1185 if (ik->super() != NULL) {
1186 Symbol* cn = ik->super()->name();
1187 resolve_super_or_fail(class_name, cn,
1188 class_loader, Handle(), true, CHECK_(nh));
1189 }
1190
1191 Array<Klass*>* interfaces = ik->local_interfaces();
1192 int num_interfaces = interfaces->length();
1193 for (int index = 0; index < num_interfaces; index++) {
1194 Klass* k = interfaces->at(index);
1195
1196 // Note: can not use InstanceKlass::cast here because
1197 // interfaces' InstanceKlass's C++ vtbls haven't been
1198 // reinitialized yet (they will be once the interface classes
1199 // are loaded)
1200 Symbol* name = k->name();
1201 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1202 }
1203
1204 // Adjust methods to recover missing data. They need addresses for
1205 // interpreter entry points and their default native method address
1206 // must be reset.
1207
1208 // Updating methods must be done under a lock so multiple
1209 // threads don't update these in parallel
1210 // Shared classes are all currently loaded by the bootstrap
1211 // classloader, so this will never cause a deadlock on
1212 // a custom class loader lock.
1213
1214 {
1215 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1216 check_loader_lock_contention(lockObject, THREAD);
1217 ObjectLocker ol(lockObject, THREAD, true);
1218 ik->restore_unshareable_info(CHECK_(nh));
1219 }
1220
1221 if (TraceClassLoading) {
1222 ResourceMark rm;
1223 tty->print("[Loaded %s", ik->external_name());
1224 tty->print(" from shared objects file");
1225 tty->print_cr("]");
1226 }
1227 // notify a class loaded from shared object
1228 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1229 true /* shared class */);
1230 }
1231 return ik;
1232 }
1233
1234
1235 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1236 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1237 if (class_loader.is_null()) {
1238
1239 // Search the shared system dictionary for classes preloaded into the
1240 // shared spaces.
1241 instanceKlassHandle k;
1242 {
1243 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1244 k = load_shared_class(class_name, class_loader, THREAD);
1245 }
1246
1247 if (k.is_null()) {
1248 // Use VM class loader
1249 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1250 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1251 }
1252
1253 // find_or_define_instance_class may return a different InstanceKlass
1254 if (!k.is_null()) {
1255 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1256 }
1257 return k;
1258 } else {
1259 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1260 ResourceMark rm(THREAD);
1261
1262 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1263 JavaThread* jt = (JavaThread*) THREAD;
1264
1265 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1266 ClassLoader::perf_app_classload_selftime(),
1267 ClassLoader::perf_app_classload_count(),
1268 jt->get_thread_stat()->perf_recursion_counts_addr(),
1269 jt->get_thread_stat()->perf_timers_addr(),
1270 PerfClassTraceTime::CLASS_LOAD);
1271
1272 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1273 // Translate to external class name format, i.e., convert '/' chars to '.'
1274 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1275
1276 JavaValue result(T_OBJECT);
1277
1278 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1279
1280 // Call public unsynchronized loadClass(String) directly for all class loaders
1281 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1282 // acquire a class-name based lock rather than the class loader object lock.
1283 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1284 // so the call to loadClassInternal() was not required.
1285 //
1286 // UnsyncloadClass flag means both call loadClass(String) and do
1287 // not acquire the class loader lock even for class loaders that are
1288 // not parallelCapable. This was a risky transitional
1289 // flag for diagnostic purposes only. It is risky to call
1290 // custom class loaders without synchronization.
1291 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1292 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1293 // Do NOT assume this will be supported in future releases.
1294 //
1295 // Added MustCallLoadClassInternal in case we discover in the field
1296 // a customer that counts on this call
1297 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1298 JavaCalls::call_special(&result,
1299 class_loader,
1300 spec_klass,
1301 vmSymbols::loadClassInternal_name(),
1302 vmSymbols::string_class_signature(),
1303 string,
1304 CHECK_(nh));
1305 } else {
1306 JavaCalls::call_virtual(&result,
1307 class_loader,
1308 spec_klass,
1309 vmSymbols::loadClass_name(),
1310 vmSymbols::string_class_signature(),
1311 string,
1312 CHECK_(nh));
1313 }
1314
1315 assert(result.get_type() == T_OBJECT, "just checking");
1316 oop obj = (oop) result.get_jobject();
1317
1318 // Primitive classes return null since forName() can not be
1319 // used to obtain any of the Class objects representing primitives or void
1320 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1321 instanceKlassHandle k =
1322 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1323 // For user defined Java class loaders, check that the name returned is
1324 // the same as that requested. This check is done for the bootstrap
1325 // loader when parsing the class file.
1326 if (class_name == k->name()) {
1327 return k;
1328 }
1329 }
1330 // Class is not found or has the wrong name, return NULL
1331 return nh;
1332 }
1333 }
1334
1335 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1336
1337 ClassLoaderData* loader_data = k->class_loader_data();
1338 Handle class_loader_h(THREAD, loader_data->class_loader());
1339
1340 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1341
1342 // for bootstrap and other parallel classloaders don't acquire lock,
1343 // use placeholder token
1344 // If a parallelCapable class loader calls define_instance_class instead of
1345 // find_or_define_instance_class to get here, we have a timing
1346 // hole with systemDictionary updates and check_constraints
1347 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1348 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1349 compute_loader_lock_object(class_loader_h, THREAD)),
1350 "define called without lock");
1351 }
1352
1353 // Check class-loading constraints. Throw exception if violation is detected.
1354 // Grabs and releases SystemDictionary_lock
1355 // The check_constraints/find_class call and update_dictionary sequence
1356 // must be "atomic" for a specific class/classloader pair so we never
1357 // define two different instanceKlasses for that class/classloader pair.
1358 // Existing classloaders will call define_instance_class with the
1359 // classloader lock held
1360 // Parallel classloaders will call find_or_define_instance_class
1361 // which will require a token to perform the define class
1362 Symbol* name_h = k->name();
1363 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1364 int d_index = dictionary()->hash_to_index(d_hash);
1365 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1366
1367 // Register class just loaded with class loader (placed in Vector)
1368 // Note we do this before updating the dictionary, as this can
1369 // fail with an OutOfMemoryError (if it does, we will *not* put this
1370 // class in the dictionary and will not update the class hierarchy).
1371 // JVMTI FollowReferences needs to find the classes this way.
1372 if (k->class_loader() != NULL) {
1373 methodHandle m(THREAD, Universe::loader_addClass_method());
1374 JavaValue result(T_VOID);
1375 JavaCallArguments args(class_loader_h);
1376 args.push_oop(Handle(THREAD, k->java_mirror()));
1377 JavaCalls::call(&result, m, &args, CHECK);
1378 }
1379
1380 // Add the new class. We need recompile lock during update of CHA.
1381 {
1382 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1383 int p_index = placeholders()->hash_to_index(p_hash);
1384
1385 MutexLocker mu_r(Compile_lock, THREAD);
1386
1387 // Add to class hierarchy, initialize vtables, and do possible
1388 // deoptimizations.
1389 add_to_hierarchy(k, CHECK); // No exception, but can block
1390
1391 // Add to systemDictionary - so other classes can see it.
1392 // Grabs and releases SystemDictionary_lock
1393 update_dictionary(d_index, d_hash, p_index, p_hash,
1394 k, class_loader_h, THREAD);
1395 }
1396 k->eager_initialize(THREAD);
1397
1398 // notify jvmti
1399 if (JvmtiExport::should_post_class_load()) {
1400 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1401 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1402
1403 }
1404
1405 }
1406
1407 // Support parallel classloading
1408 // All parallel class loaders, including bootstrap classloader
1409 // lock a placeholder entry for this class/class_loader pair
1410 // to allow parallel defines of different classes for this class loader
1411 // With AllowParallelDefine flag==true, in case they do not synchronize around
1412 // FindLoadedClass/DefineClass, calls, we check for parallel
1413 // loading for them, wait if a defineClass is in progress
1414 // and return the initial requestor's results
1415 // This flag does not apply to the bootstrap classloader.
1416 // With AllowParallelDefine flag==false, call through to define_instance_class
1417 // which will throw LinkageError: duplicate class definition.
1418 // False is the requested default.
1419 // For better performance, the class loaders should synchronize
1420 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1421 // potentially waste time reading and parsing the bytestream.
1422 // Note: VM callers should ensure consistency of k/class_name,class_loader
1423 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1424
1425 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1426 Symbol* name_h = k->name(); // passed in class_name may be null
1427 ClassLoaderData* loader_data = class_loader_data(class_loader);
1428
1429 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1430 int d_index = dictionary()->hash_to_index(d_hash);
1431
1432 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1433 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1434 int p_index = placeholders()->hash_to_index(p_hash);
1435 PlaceholderEntry* probe;
1436
1437 {
1438 MutexLocker mu(SystemDictionary_lock, THREAD);
1439 // First check if class already defined
1440 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1441 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1442 if (check != NULL) {
1443 return(instanceKlassHandle(THREAD, check));
1444 }
1445 }
1446
1447 // Acquire define token for this class/classloader
1448 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1449 // Wait if another thread defining in parallel
1450 // All threads wait - even those that will throw duplicate class: otherwise
1451 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1452 // if other thread has not finished updating dictionary
1453 while (probe->definer() != NULL) {
1454 SystemDictionary_lock->wait();
1455 }
1456 // Only special cases allow parallel defines and can use other thread's results
1457 // Other cases fall through, and may run into duplicate defines
1458 // caught by finding an entry in the SystemDictionary
1459 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1460 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1461 SystemDictionary_lock->notify_all();
1462 #ifdef ASSERT
1463 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1464 assert(check != NULL, "definer missed recording success");
1465 #endif
1466 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1467 } else {
1468 // This thread will define the class (even if earlier thread tried and had an error)
1469 probe->set_definer(THREAD);
1470 }
1471 }
1472
1473 define_instance_class(k, THREAD);
1474
1475 Handle linkage_exception = Handle(); // null handle
1476
1477 // definer must notify any waiting threads
1478 {
1479 MutexLocker mu(SystemDictionary_lock, THREAD);
1480 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1481 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1482 if (probe != NULL) {
1483 if (HAS_PENDING_EXCEPTION) {
1484 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1485 CLEAR_PENDING_EXCEPTION;
1486 } else {
1487 probe->set_instance_klass(k());
1488 }
1489 probe->set_definer(NULL);
1490 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1491 SystemDictionary_lock->notify_all();
1492 }
1493 }
1494
1495 // Can't throw exception while holding lock due to rank ordering
1496 if (linkage_exception() != NULL) {
1497 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1498 }
1499
1500 return k;
1501 }
1502 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1503 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1504 if (class_loader.is_null()) {
1505 return Handle(THREAD, _system_loader_lock_obj);
1506 } else {
1507 return class_loader;
1508 }
1509 }
1510
1511 // This method is added to check how often we have to wait to grab loader
1512 // lock. The results are being recorded in the performance counters defined in
1513 // ClassLoader::_sync_systemLoaderLockContentionRate and
1514 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1515 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1516 if (!UsePerfData) {
1517 return;
1518 }
1519
1520 assert(!loader_lock.is_null(), "NULL lock object");
1521
1522 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1523 == ObjectSynchronizer::owner_other) {
1524 // contention will likely happen, so increment the corresponding
1525 // contention counter.
1526 if (loader_lock() == _system_loader_lock_obj) {
1527 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1528 } else {
1529 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1530 }
1531 }
1532 }
1533
1534 // ----------------------------------------------------------------------------
1535 // Lookup
1536
1537 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1538 Symbol* class_name,
1539 ClassLoaderData* loader_data) {
1540 assert_locked_or_safepoint(SystemDictionary_lock);
1541 assert (index == dictionary()->index_for(class_name, loader_data),
1542 "incorrect index?");
1543
1544 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1545 return k;
1546 }
1547
1548
1549 // Basic find on classes in the midst of being loaded
1550 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1551 ClassLoaderData* loader_data) {
1552 assert_locked_or_safepoint(SystemDictionary_lock);
1553 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1554 int p_index = placeholders()->hash_to_index(p_hash);
1555 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1556 }
1557
1558
1559 // Used for assertions and verification only
1560 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1561 #ifndef ASSERT
1562 guarantee(VerifyBeforeGC ||
1563 VerifyDuringGC ||
1564 VerifyBeforeExit ||
1565 VerifyDuringStartup ||
1566 VerifyAfterGC, "too expensive");
1567 #endif
1568 assert_locked_or_safepoint(SystemDictionary_lock);
1569
1570 // First look in the loaded class array
1571 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1572 int d_index = dictionary()->hash_to_index(d_hash);
1573 return find_class(d_index, d_hash, class_name, loader_data);
1574 }
1575
1576
1577 // Get the next class in the diictionary.
1578 Klass* SystemDictionary::try_get_next_class() {
1579 return dictionary()->try_get_next_class();
1580 }
1581
1582
1583 // ----------------------------------------------------------------------------
1584 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1585 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1586 // before a new class is used.
1587
1588 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1589 assert(k.not_null(), "just checking");
1590 assert_locked_or_safepoint(Compile_lock);
1591
1592 // Link into hierachy. Make sure the vtables are initialized before linking into
1593 k->append_to_sibling_list(); // add to superklass/sibling list
1594 k->process_interfaces(THREAD); // handle all "implements" declarations
1595 k->set_init_state(InstanceKlass::loaded);
1596 // Now flush all code that depended on old class hierarchy.
1597 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1598 // Also, first reinitialize vtable because it may have gotten out of synch
1599 // while the new class wasn't connected to the class hierarchy.
1600 Universe::flush_dependents_on(k);
1601 }
1602
1603
1604 // ----------------------------------------------------------------------------
1605 // GC support
1606
1607 // Following roots during mark-sweep is separated in two phases.
1608 //
1609 // The first phase follows preloaded classes and all other system
1610 // classes, since these will never get unloaded anyway.
1611 //
1612 // The second phase removes (unloads) unreachable classes from the
1613 // system dictionary and follows the remaining classes' contents.
1614
1615 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1616 blk->do_oop(&_java_system_loader);
1617 blk->do_oop(&_system_loader_lock_obj);
1618
1619 dictionary()->always_strong_oops_do(blk);
1620
1621 // Visit extra methods
1622 invoke_method_table()->oops_do(blk);
1623 }
1624
1625 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1626 // Follow all system classes and temporary placeholders in dictionary
1627 dictionary()->always_strong_classes_do(closure);
1628
1629 // Placeholders. These represent classes we're actively loading.
1630 placeholders()->classes_do(closure);
1631 }
1632
1633 // Calculate a "good" systemdictionary size based
1634 // on predicted or current loaded classes count
1635 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1636 int newsize = _old_default_sdsize;
1637 if ((classcount > 0) && !DumpSharedSpaces) {
1638 int desiredsize = classcount/_average_depth_goal;
1639 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1640 newsize = _primelist[++_sdgeneration]) {
1641 if (desiredsize <= newsize) {
1642 break;
1643 }
1644 }
1645 }
1646 return newsize;
1647 }
1648
1649 #ifdef ASSERT
1650 class VerifySDReachableAndLiveClosure : public OopClosure {
1651 private:
1652 BoolObjectClosure* _is_alive;
1653
1654 template <class T> void do_oop_work(T* p) {
1655 oop obj = oopDesc::load_decode_heap_oop(p);
1656 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1657 }
1658
1659 public:
1660 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1661
1662 virtual void do_oop(oop* p) { do_oop_work(p); }
1663 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1664 };
1665 #endif
1666
1667 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1668 // Note: anonymous classes are not in the SD.
1669 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1670 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1671 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1672 bool unloading_occurred = false;
1673 if (has_dead_loaders) {
1674 unloading_occurred = dictionary()->do_unloading();
1675 constraints()->purge_loader_constraints();
1676 resolution_errors()->purge_resolution_errors();
1677 }
1678 // Oops referenced by the system dictionary may get unreachable independently
1679 // of the class loader (eg. cached protection domain oops). So we need to
1680 // explicitly unlink them here instead of in Dictionary::do_unloading.
1681 dictionary()->unlink(is_alive);
1682 #ifdef ASSERT
1683 VerifySDReachableAndLiveClosure cl(is_alive);
1684 dictionary()->oops_do(&cl);
1685 #endif
1686 return unloading_occurred;
1687 }
1688
1689 void SystemDictionary::oops_do(OopClosure* f) {
1690 f->do_oop(&_java_system_loader);
1691 f->do_oop(&_system_loader_lock_obj);
1692
1693 // Adjust dictionary
1694 dictionary()->oops_do(f);
1695
1696 // Visit extra methods
1697 invoke_method_table()->oops_do(f);
1698 }
1699
1700 // Extended Class redefinition support.
1701 // If one of these classes is replaced, we need to replace it in these places.
1702 // KlassClosure::do_klass should take the address of a class but we can
1703 // change that later.
1704 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1705 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1706 f->do_klass(_well_known_klasses[k]);
1707 }
1708
1709 {
1710 for (int i = 0; i < T_VOID+1; i++) {
1711 if (_box_klasses[i] != NULL) {
1712 assert(i >= T_BOOLEAN, "checking");
1713 f->do_klass(_box_klasses[i]);
1714 }
1715 }
1716 }
1717
1718 FilteredFieldsMap::classes_do(f);
1719 }
1720
1721 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1722 f->do_klass(_abstract_ownable_synchronizer_klass);
1723 }
1724
1725 // Just the classes from defining class loaders
1726 // Don't iterate over placeholders
1727 void SystemDictionary::classes_do(void f(Klass*)) {
1728 dictionary()->classes_do(f);
1729 }
1730
1731 // Added for initialize_itable_for_klass
1732 // Just the classes from defining class loaders
1733 // Don't iterate over placeholders
1734 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1735 dictionary()->classes_do(f, CHECK);
1736 }
1737
1738 // All classes, and their class loaders
1739 // Don't iterate over placeholders
1740 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1741 dictionary()->classes_do(f);
1742 }
1743
1744 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1745 placeholders()->entries_do(f);
1746 }
1747
1748 void SystemDictionary::methods_do(void f(Method*)) {
1749 dictionary()->methods_do(f);
1750 invoke_method_table()->methods_do(f);
1751 }
1752
1753 // ----------------------------------------------------------------------------
1754 // Lazily load klasses
1755
1756 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1757 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1758
1759 // if multiple threads calling this function, only one thread will load
1760 // the class. The other threads will find the loaded version once the
1761 // class is loaded.
1762 Klass* aos = _abstract_ownable_synchronizer_klass;
1763 if (aos == NULL) {
1764 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1765 // Force a fence to prevent any read before the write completes
1766 OrderAccess::fence();
1767 _abstract_ownable_synchronizer_klass = k;
1768 }
1769 }
1770
1771 // ----------------------------------------------------------------------------
1772 // Initialization
1773
1774 void SystemDictionary::initialize(TRAPS) {
1775 // Allocate arrays
1776 assert(dictionary() == NULL,
1777 "SystemDictionary should only be initialized once");
1778 _sdgeneration = 0;
1779 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1780 _placeholders = new PlaceholderTable(_nof_buckets);
1781 _number_of_modifications = 0;
1782 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1783 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1784 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1785
1786 // Allocate private object used as system class loader lock
1787 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1788 // Initialize basic classes
1789 initialize_preloaded_classes(CHECK);
1790 }
1791
1792 // Compact table of directions on the initialization of klasses:
1793 static const short wk_init_info[] = {
1794 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1795 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1796 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1797 | (int)SystemDictionary::option ),
1798 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1799 #undef WK_KLASS_INIT_INFO
1800 0
1801 };
1802
1803 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1804 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1805 int info = wk_init_info[id - FIRST_WKID];
1806 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1807 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1808 Klass** klassp = &_well_known_klasses[id];
1809 bool must_load = (init_opt < SystemDictionary::Opt);
1810 if ((*klassp) == NULL) {
1811 if (must_load) {
1812 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1813 } else {
1814 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1815 }
1816 }
1817 return ((*klassp) != NULL);
1818 }
1819
1820 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1821 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1822 for (int id = (int)start_id; id < (int)limit_id; id++) {
1823 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1824 int info = wk_init_info[id - FIRST_WKID];
1825 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1826 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1827
1828 initialize_wk_klass((WKID)id, opt, CHECK);
1829 }
1830
1831 // move the starting value forward to the limit:
1832 start_id = limit_id;
1833 }
1834
1835 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1836 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1837 // Preload commonly used klasses
1838 WKID scan = FIRST_WKID;
1839 // first do Object, then String, Class
1840 if (UseSharedSpaces) {
1841 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1842 // Initialize the constant pool for the Object_class
1843 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1844 ik->constants()->restore_unshareable_info(CHECK);
1845 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1846 } else {
1847 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1848 }
1849
1850 // Calculate offsets for String and Class classes since they are loaded and
1851 // can be used after this point.
1852 java_lang_String::compute_offsets();
1853 java_lang_Class::compute_offsets();
1854
1855 // Fixup mirrors for classes loaded before java.lang.Class.
1856 // These calls iterate over the objects currently in the perm gen
1857 // so calling them at this point is matters (not before when there
1858 // are fewer objects and not later after there are more objects
1859 // in the perm gen.
1860 Universe::initialize_basic_type_mirrors(CHECK);
1861 Universe::fixup_mirrors(CHECK);
1862
1863 // do a bunch more:
1864 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1865
1866 // Preload ref klasses and set reference types
1867 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1868 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1869
1870 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1871 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1872 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1873 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1874 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1875
1876 // JSR 292 classes
1877 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1878 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1879 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1880 if (EnableInvokeDynamic) {
1881 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1882 } else {
1883 // Skip the JSR 292 classes, if not enabled.
1884 scan = WKID(jsr292_group_end + 1);
1885 }
1886
1887 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1888
1889 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1890 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1891 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1892 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1893 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1894 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1895 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1896 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1897 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1898 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1899
1900 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1901 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1902 _has_loadClassInternal = (method != NULL);
1903 }
1904 { // Compute whether we should use checkPackageAccess or NOT
1905 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1906 _has_checkPackageAccess = (method != NULL);
1907 }
1908 }
1909
1910 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1911 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1912 BasicType SystemDictionary::box_klass_type(Klass* k) {
1913 assert(k != NULL, "");
1914 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1915 if (_box_klasses[i] == k)
1916 return (BasicType)i;
1917 }
1918 return T_OBJECT;
1919 }
1920
1921 // Constraints on class loaders. The details of the algorithm can be
1922 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1923 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1924 // that the system dictionary needs to maintain a set of contraints that
1925 // must be satisfied by all classes in the dictionary.
1926 // if defining is true, then LinkageError if already in systemDictionary
1927 // if initiating loader, then ok if InstanceKlass matches existing entry
1928
1929 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1930 instanceKlassHandle k,
1931 Handle class_loader, bool defining,
1932 TRAPS) {
1933 const char *linkage_error = NULL;
1934 {
1935 Symbol* name = k->name();
1936 ClassLoaderData *loader_data = class_loader_data(class_loader);
1937
1938 MutexLocker mu(SystemDictionary_lock, THREAD);
1939
1940 Klass* check = find_class(d_index, d_hash, name, loader_data);
1941 if (check != (Klass*)NULL) {
1942 // if different InstanceKlass - duplicate class definition,
1943 // else - ok, class loaded by a different thread in parallel,
1944 // we should only have found it if it was done loading and ok to use
1945 // system dictionary only holds instance classes, placeholders
1946 // also holds array classes
1947
1948 assert(check->oop_is_instance(), "noninstance in systemdictionary");
1949 if ((defining == true) || (k() != check)) {
1950 linkage_error = "loader (instance of %s): attempted duplicate class "
1951 "definition for name: \"%s\"";
1952 } else {
1953 return;
1954 }
1955 }
1956
1957 #ifdef ASSERT
1958 Symbol* ph_check = find_placeholder(name, loader_data);
1959 assert(ph_check == NULL || ph_check == name, "invalid symbol");
1960 #endif
1961
1962 if (linkage_error == NULL) {
1963 if (constraints()->check_or_update(k, class_loader, name) == false) {
1964 linkage_error = "loader constraint violation: loader (instance of %s)"
1965 " previously initiated loading for a different type with name \"%s\"";
1966 }
1967 }
1968 }
1969
1970 // Throw error now if needed (cannot throw while holding
1971 // SystemDictionary_lock because of rank ordering)
1972
1973 if (linkage_error) {
1974 ResourceMark rm(THREAD);
1975 const char* class_loader_name = loader_name(class_loader());
1976 char* type_name = k->name()->as_C_string();
1977 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1978 strlen(type_name);
1979 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1980 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1981 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1982 }
1983 }
1984
1985
1986 // Update system dictionary - done after check_constraint and add_to_hierachy
1987 // have been called.
1988 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1989 int p_index, unsigned int p_hash,
1990 instanceKlassHandle k,
1991 Handle class_loader,
1992 TRAPS) {
1993 // Compile_lock prevents systemDictionary updates during compilations
1994 assert_locked_or_safepoint(Compile_lock);
1995 Symbol* name = k->name();
1996 ClassLoaderData *loader_data = class_loader_data(class_loader);
1997
1998 {
1999 MutexLocker mu1(SystemDictionary_lock, THREAD);
2000
2001 // See whether biased locking is enabled and if so set it for this
2002 // klass.
2003 // Note that this must be done past the last potential blocking
2004 // point / safepoint. We enable biased locking lazily using a
2005 // VM_Operation to iterate the SystemDictionary and installing the
2006 // biasable mark word into each InstanceKlass's prototype header.
2007 // To avoid race conditions where we accidentally miss enabling the
2008 // optimization for one class in the process of being added to the
2009 // dictionary, we must not safepoint after the test of
2010 // BiasedLocking::enabled().
2011 if (UseBiasedLocking && BiasedLocking::enabled()) {
2012 // Set biased locking bit for all loaded classes; it will be
2013 // cleared if revocation occurs too often for this type
2014 // NOTE that we must only do this when the class is initally
2015 // defined, not each time it is referenced from a new class loader
2016 if (k->class_loader() == class_loader()) {
2017 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2018 }
2019 }
2020
2021 // Make a new system dictionary entry.
2022 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2023 if (sd_check == NULL) {
2024 dictionary()->add_klass(name, loader_data, k);
2025 notice_modification();
2026 }
2027 #ifdef ASSERT
2028 sd_check = find_class(d_index, d_hash, name, loader_data);
2029 assert (sd_check != NULL, "should have entry in system dictionary");
2030 // Note: there may be a placeholder entry: for circularity testing
2031 // or for parallel defines
2032 #endif
2033 SystemDictionary_lock->notify_all();
2034 }
2035 }
2036
2037
2038 // Try to find a class name using the loader constraints. The
2039 // loader constraints might know about a class that isn't fully loaded
2040 // yet and these will be ignored.
2041 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2042 Symbol* class_name, Handle class_loader, TRAPS) {
2043
2044 // First see if it has been loaded directly.
2045 // Force the protection domain to be null. (This removes protection checks.)
2046 Handle no_protection_domain;
2047 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2048 no_protection_domain, CHECK_NULL);
2049 if (klass != NULL)
2050 return klass;
2051
2052 // Now look to see if it has been loaded elsewhere, and is subject to
2053 // a loader constraint that would require this loader to return the
2054 // klass that is already loaded.
2055 if (FieldType::is_array(class_name)) {
2056 // For array classes, their Klass*s are not kept in the
2057 // constraint table. The element Klass*s are.
2058 FieldArrayInfo fd;
2059 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2060 if (t != T_OBJECT) {
2061 klass = Universe::typeArrayKlassObj(t);
2062 } else {
2063 MutexLocker mu(SystemDictionary_lock, THREAD);
2064 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2065 }
2066 // If element class already loaded, allocate array klass
2067 if (klass != NULL) {
2068 klass = klass->array_klass_or_null(fd.dimension());
2069 }
2070 } else {
2071 MutexLocker mu(SystemDictionary_lock, THREAD);
2072 // Non-array classes are easy: simply check the constraint table.
2073 klass = constraints()->find_constrained_klass(class_name, class_loader);
2074 }
2075
2076 return klass;
2077 }
2078
2079
2080 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2081 Handle class_loader1,
2082 Handle class_loader2,
2083 Thread* THREAD) {
2084 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2085 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2086
2087 Symbol* constraint_name = NULL;
2088 if (!FieldType::is_array(class_name)) {
2089 constraint_name = class_name;
2090 } else {
2091 // For array classes, their Klass*s are not kept in the
2092 // constraint table. The element classes are.
2093 FieldArrayInfo fd;
2094 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2095 // primitive types always pass
2096 if (t != T_OBJECT) {
2097 return true;
2098 } else {
2099 constraint_name = fd.object_key();
2100 }
2101 }
2102 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2103 int d_index1 = dictionary()->hash_to_index(d_hash1);
2104
2105 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2106 int d_index2 = dictionary()->hash_to_index(d_hash2);
2107 {
2108 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2109
2110 // Better never do a GC while we're holding these oops
2111 No_Safepoint_Verifier nosafepoint;
2112
2113 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2114 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2115 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2116 klass2, class_loader2);
2117 }
2118 }
2119
2120 // Add entry to resolution error table to record the error when the first
2121 // attempt to resolve a reference to a class has failed.
2122 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2123 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2124 int index = resolution_errors()->hash_to_index(hash);
2125 {
2126 MutexLocker ml(SystemDictionary_lock, Thread::current());
2127 resolution_errors()->add_entry(index, hash, pool, which, error);
2128 }
2129 }
2130
2131 // Delete a resolution error for RedefineClasses for a constant pool is going away
2132 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2133 resolution_errors()->delete_entry(pool);
2134 }
2135
2136 // Lookup resolution error table. Returns error if found, otherwise NULL.
2137 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2138 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2139 int index = resolution_errors()->hash_to_index(hash);
2140 {
2141 MutexLocker ml(SystemDictionary_lock, Thread::current());
2142 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2143 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2144 }
2145 }
2146
2147
2148 // Signature constraints ensure that callers and callees agree about
2149 // the meaning of type names in their signatures. This routine is the
2150 // intake for constraints. It collects them from several places:
2151 //
2152 // * LinkResolver::resolve_method (if check_access is true) requires
2153 // that the resolving class (the caller) and the defining class of
2154 // the resolved method (the callee) agree on each type in the
2155 // method's signature.
2156 //
2157 // * LinkResolver::resolve_interface_method performs exactly the same
2158 // checks.
2159 //
2160 // * LinkResolver::resolve_field requires that the constant pool
2161 // attempting to link to a field agree with the field's defining
2162 // class about the type of the field signature.
2163 //
2164 // * klassVtable::initialize_vtable requires that, when a class
2165 // overrides a vtable entry allocated by a superclass, that the
2166 // overriding method (i.e., the callee) agree with the superclass
2167 // on each type in the method's signature.
2168 //
2169 // * klassItable::initialize_itable requires that, when a class fills
2170 // in its itables, for each non-abstract method installed in an
2171 // itable, the method (i.e., the callee) agree with the interface
2172 // on each type in the method's signature.
2173 //
2174 // All those methods have a boolean (check_access, checkconstraints)
2175 // which turns off the checks. This is used from specialized contexts
2176 // such as bootstrapping, dumping, and debugging.
2177 //
2178 // No direct constraint is placed between the class and its
2179 // supertypes. Constraints are only placed along linked relations
2180 // between callers and callees. When a method overrides or implements
2181 // an abstract method in a supertype (superclass or interface), the
2182 // constraints are placed as if the supertype were the caller to the
2183 // overriding method. (This works well, since callers to the
2184 // supertype have already established agreement between themselves and
2185 // the supertype.) As a result of all this, a class can disagree with
2186 // its supertype about the meaning of a type name, as long as that
2187 // class neither calls a relevant method of the supertype, nor is
2188 // called (perhaps via an override) from the supertype.
2189 //
2190 //
2191 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2192 //
2193 // Make sure all class components (including arrays) in the given
2194 // signature will be resolved to the same class in both loaders.
2195 // Returns the name of the type that failed a loader constraint check, or
2196 // NULL if no constraint failed. No exception except OOME is thrown.
2197 // Arrays are not added to the loader constraint table, their elements are.
2198 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2199 Handle loader1, Handle loader2,
2200 bool is_method, TRAPS) {
2201 // Nothing to do if loaders are the same.
2202 if (loader1() == loader2()) {
2203 return NULL;
2204 }
2205
2206 SignatureStream sig_strm(signature, is_method);
2207 while (!sig_strm.is_done()) {
2208 if (sig_strm.is_object()) {
2209 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2210 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2211 return sig;
2212 }
2213 }
2214 sig_strm.next();
2215 }
2216 return NULL;
2217 }
2218
2219
2220 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2221 Symbol* signature,
2222 TRAPS) {
2223 methodHandle empty;
2224 assert(EnableInvokeDynamic, "");
2225 assert(MethodHandles::is_signature_polymorphic(iid) &&
2226 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2227 iid != vmIntrinsics::_invokeGeneric,
2228 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2229
2230 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2231 int index = invoke_method_table()->hash_to_index(hash);
2232 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2233 methodHandle m;
2234 if (spe == NULL || spe->method() == NULL) {
2235 spe = NULL;
2236 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2237 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2238 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2239 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2240
2241 // Now grab the lock. We might have to throw away the new method,
2242 // if a racing thread has managed to install one at the same time.
2243 {
2244 MutexLocker ml(SystemDictionary_lock, THREAD);
2245 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2246 if (spe == NULL)
2247 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2248 if (spe->method() == NULL)
2249 spe->set_method(m());
2250 }
2251 }
2252
2253 assert(spe != NULL && spe->method() != NULL, "");
2254 return spe->method();
2255 }
2256
2257 // Helper for unpacking the return value from linkMethod and linkCallSite.
2258 static methodHandle unpack_method_and_appendix(Handle mname,
2259 KlassHandle accessing_klass,
2260 objArrayHandle appendix_box,
2261 Handle* appendix_result,
2262 TRAPS) {
2263 methodHandle empty;
2264 if (mname.not_null()) {
2265 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2266 if (vmtarget != NULL && vmtarget->is_method()) {
2267 Method* m = (Method*)vmtarget;
2268 oop appendix = appendix_box->obj_at(0);
2269 if (TraceMethodHandles) {
2270 #ifndef PRODUCT
2271 tty->print("Linked method="INTPTR_FORMAT": ", m);
2272 m->print();
2273 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2274 tty->cr();
2275 #endif //PRODUCT
2276 }
2277 (*appendix_result) = Handle(THREAD, appendix);
2278 // the target is stored in the cpCache and if a reference to this
2279 // MethodName is dropped we need a way to make sure the
2280 // class_loader containing this method is kept alive.
2281 // FIXME: the appendix might also preserve this dependency.
2282 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2283 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2284 return methodHandle(THREAD, m);
2285 }
2286 }
2287 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2288 return empty;
2289 }
2290
2291 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2292 Symbol* signature,
2293 KlassHandle accessing_klass,
2294 Handle *appendix_result,
2295 Handle *method_type_result,
2296 TRAPS) {
2297 methodHandle empty;
2298 assert(EnableInvokeDynamic, "");
2299 assert(!THREAD->is_Compiler_thread(), "");
2300 Handle method_type =
2301 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2302 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2303 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2304 }
2305
2306 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2307 int ref_kind = JVM_REF_invokeVirtual;
2308 Handle name_str = StringTable::intern(name, CHECK_(empty));
2309 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2310 assert(appendix_box->obj_at(0) == NULL, "");
2311
2312 // This should not happen. JDK code should take care of that.
2313 if (accessing_klass.is_null() || method_type.is_null()) {
2314 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2315 }
2316
2317 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2318 JavaCallArguments args;
2319 args.push_oop(accessing_klass()->java_mirror());
2320 args.push_int(ref_kind);
2321 args.push_oop(mh_klass()->java_mirror());
2322 args.push_oop(name_str());
2323 args.push_oop(method_type());
2324 args.push_oop(appendix_box());
2325 JavaValue result(T_OBJECT);
2326 JavaCalls::call_static(&result,
2327 SystemDictionary::MethodHandleNatives_klass(),
2328 vmSymbols::linkMethod_name(),
2329 vmSymbols::linkMethod_signature(),
2330 &args, CHECK_(empty));
2331 Handle mname(THREAD, (oop) result.get_jobject());
2332 (*method_type_result) = method_type;
2333 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2334 }
2335
2336
2337 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2338 // signature, as interpreted relative to the given class loader.
2339 // Because of class loader constraints, all method handle usage must be
2340 // consistent with this loader.
2341 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2342 KlassHandle accessing_klass,
2343 TRAPS) {
2344 Handle empty;
2345 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2346 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2347 int index = invoke_method_table()->hash_to_index(hash);
2348 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2349 if (spe != NULL && spe->method_type() != NULL) {
2350 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2351 return Handle(THREAD, spe->method_type());
2352 } else if (THREAD->is_Compiler_thread()) {
2353 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2354 return Handle(); // do not attempt from within compiler, unless it was cached
2355 }
2356
2357 Handle class_loader, protection_domain;
2358 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2359 int npts = ArgumentCount(signature).size();
2360 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2361 int arg = 0;
2362 Handle rt; // the return type from the signature
2363 ResourceMark rm(THREAD);
2364 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2365 oop mirror = NULL;
2366 if (is_on_bcp) {
2367 // Note: class_loader & protection_domain are both null at this point.
2368 mirror = ss.as_java_mirror(class_loader, protection_domain,
2369 SignatureStream::ReturnNull, CHECK_(empty));
2370 if (mirror == NULL) {
2371 // fall back from BCP to accessing_klass
2372 if (accessing_klass.not_null()) {
2373 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2374 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2375 }
2376 is_on_bcp = false;
2377 }
2378 }
2379 if (!is_on_bcp) {
2380 // Resolve, throwing a real error if it doesn't work.
2381 mirror = ss.as_java_mirror(class_loader, protection_domain,
2382 SignatureStream::NCDFError, CHECK_(empty));
2383 }
2384 if (ss.at_return_type())
2385 rt = Handle(THREAD, mirror);
2386 else
2387 pts->obj_at_put(arg++, mirror);
2388
2389 // Check accessibility.
2390 if (ss.is_object() && accessing_klass.not_null()) {
2391 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2392 mirror = NULL; // safety
2393 // Emulate ConstantPool::verify_constant_pool_resolve.
2394 if (sel_klass->oop_is_objArray())
2395 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2396 if (sel_klass->oop_is_instance()) {
2397 KlassHandle sel_kh(THREAD, sel_klass);
2398 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2399 }
2400 }
2401 }
2402 assert(arg == npts, "");
2403
2404 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2405 JavaCallArguments args(Handle(THREAD, rt()));
2406 args.push_oop(pts());
2407 JavaValue result(T_OBJECT);
2408 JavaCalls::call_static(&result,
2409 SystemDictionary::MethodHandleNatives_klass(),
2410 vmSymbols::findMethodHandleType_name(),
2411 vmSymbols::findMethodHandleType_signature(),
2412 &args, CHECK_(empty));
2413 Handle method_type(THREAD, (oop) result.get_jobject());
2414
2415 if (is_on_bcp) {
2416 // We can cache this MethodType inside the JVM.
2417 MutexLocker ml(SystemDictionary_lock, THREAD);
2418 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2419 if (spe == NULL)
2420 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2421 if (spe->method_type() == NULL) {
2422 spe->set_method_type(method_type());
2423 }
2424 }
2425
2426 // report back to the caller with the MethodType
2427 return method_type;
2428 }
2429
2430 // Ask Java code to find or construct a method handle constant.
2431 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2432 int ref_kind, //e.g., JVM_REF_invokeVirtual
2433 KlassHandle callee,
2434 Symbol* name_sym,
2435 Symbol* signature,
2436 TRAPS) {
2437 Handle empty;
2438 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2439 Handle type;
2440 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2441 type = find_method_handle_type(signature, caller, CHECK_(empty));
2442 } else if (caller.is_null()) {
2443 // This should not happen. JDK code should take care of that.
2444 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2445 } else {
2446 ResourceMark rm(THREAD);
2447 SignatureStream ss(signature, false);
2448 if (!ss.is_done()) {
2449 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2450 SignatureStream::NCDFError, CHECK_(empty));
2451 type = Handle(THREAD, mirror);
2452 ss.next();
2453 if (!ss.is_done()) type = Handle(); // error!
2454 }
2455 }
2456 if (type.is_null()) {
2457 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2458 }
2459
2460 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2461 JavaCallArguments args;
2462 args.push_oop(caller->java_mirror()); // the referring class
2463 args.push_int(ref_kind);
2464 args.push_oop(callee->java_mirror()); // the target class
2465 args.push_oop(name());
2466 args.push_oop(type());
2467 JavaValue result(T_OBJECT);
2468 JavaCalls::call_static(&result,
2469 SystemDictionary::MethodHandleNatives_klass(),
2470 vmSymbols::linkMethodHandleConstant_name(),
2471 vmSymbols::linkMethodHandleConstant_signature(),
2472 &args, CHECK_(empty));
2473 return Handle(THREAD, (oop) result.get_jobject());
2474 }
2475
2476 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2477 // name and signature, as interpreted relative to the given class loader.
2478 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2479 Handle bootstrap_specifier,
2480 Symbol* name,
2481 Symbol* type,
2482 Handle *appendix_result,
2483 Handle *method_type_result,
2484 TRAPS) {
2485 methodHandle empty;
2486 Handle bsm, info;
2487 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2488 bsm = bootstrap_specifier;
2489 } else {
2490 assert(bootstrap_specifier->is_objArray(), "");
2491 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2492 int len = args->length();
2493 assert(len >= 1, "");
2494 bsm = Handle(THREAD, args->obj_at(0));
2495 if (len > 1) {
2496 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2497 for (int i = 1; i < len; i++)
2498 args1->obj_at_put(i-1, args->obj_at(i));
2499 info = Handle(THREAD, args1);
2500 }
2501 }
2502 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2503 "caller must supply a valid BSM");
2504
2505 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2506 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2507
2508 // This should not happen. JDK code should take care of that.
2509 if (caller.is_null() || method_type.is_null()) {
2510 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2511 }
2512
2513 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2514 assert(appendix_box->obj_at(0) == NULL, "");
2515
2516 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2517 JavaCallArguments args;
2518 args.push_oop(caller->java_mirror());
2519 args.push_oop(bsm());
2520 args.push_oop(method_name());
2521 args.push_oop(method_type());
2522 args.push_oop(info());
2523 args.push_oop(appendix_box);
2524 JavaValue result(T_OBJECT);
2525 JavaCalls::call_static(&result,
2526 SystemDictionary::MethodHandleNatives_klass(),
2527 vmSymbols::linkCallSite_name(),
2528 vmSymbols::linkCallSite_signature(),
2529 &args, CHECK_(empty));
2530 Handle mname(THREAD, (oop) result.get_jobject());
2531 (*method_type_result) = method_type;
2532 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2533 }
2534
2535 // Since the identity hash code for symbols changes when the symbols are
2536 // moved from the regular perm gen (hash in the mark word) to the shared
2537 // spaces (hash is the address), the classes loaded into the dictionary
2538 // may be in the wrong buckets.
2539
2540 void SystemDictionary::reorder_dictionary() {
2541 dictionary()->reorder_dictionary();
2542 }
2543
2544
2545 void SystemDictionary::copy_buckets(char** top, char* end) {
2546 dictionary()->copy_buckets(top, end);
2547 }
2548
2549
2550 void SystemDictionary::copy_table(char** top, char* end) {
2551 dictionary()->copy_table(top, end);
2552 }
2553
2554
2555 void SystemDictionary::reverse() {
2556 dictionary()->reverse();
2557 }
2558
2559 int SystemDictionary::number_of_classes() {
2560 return dictionary()->number_of_entries();
2561 }
2562
2563
2564 // ----------------------------------------------------------------------------
2565 #ifndef PRODUCT
2566
2567 void SystemDictionary::print() {
2568 dictionary()->print();
2569
2570 // Placeholders
2571 GCMutexLocker mu(SystemDictionary_lock);
2572 placeholders()->print();
2573
2574 // loader constraints - print under SD_lock
2575 constraints()->print();
2576 }
2577
2578 #endif
2579
2580 void SystemDictionary::verify() {
2581 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2582 guarantee(constraints() != NULL,
2583 "Verify of loader constraints failed");
2584 guarantee(dictionary()->number_of_entries() >= 0 &&
2585 placeholders()->number_of_entries() >= 0,
2586 "Verify of system dictionary failed");
2587
2588 // Verify dictionary
2589 dictionary()->verify();
2590
2591 GCMutexLocker mu(SystemDictionary_lock);
2592 placeholders()->verify();
2593
2594 // Verify constraint table
2595 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2596 constraints()->verify(dictionary(), placeholders());
2597 }
2598
2599 // utility function for class load event
2600 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2601 instanceKlassHandle k,
2602 Handle initiating_loader) {
2603 #if INCLUDE_TRACE
2604 EventClassLoad event(UNTIMED);
2605 if (event.should_commit()) {
2606 event.set_starttime(start_time);
2607 event.set_loadedClass(k());
2608 oop defining_class_loader = k->class_loader();
2609 event.set_definingClassLoader(defining_class_loader != NULL ?
2610 defining_class_loader->klass() : (Klass*)NULL);
2611 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2612 event.set_initiatingClassLoader(class_loader != NULL ?
2613 class_loader->klass() : (Klass*)NULL);
2614 event.commit();
2615 }
2616 #endif /* INCLUDE_TRACE */
2617 }
2618
2619 #ifndef PRODUCT
2620
2621 // statistics code
2622 class ClassStatistics: AllStatic {
2623 private:
2624 static int nclasses; // number of classes
2625 static int nmethods; // number of methods
2626 static int nmethoddata; // number of methodData
2627 static int class_size; // size of class objects in words
2628 static int method_size; // size of method objects in words
2629 static int debug_size; // size of debug info in methods
2630 static int methoddata_size; // size of methodData objects in words
2631
2632 static void do_class(Klass* k) {
2633 nclasses++;
2634 class_size += k->size();
2635 if (k->oop_is_instance()) {
2636 InstanceKlass* ik = (InstanceKlass*)k;
2637 class_size += ik->methods()->size();
2638 class_size += ik->constants()->size();
2639 class_size += ik->local_interfaces()->size();
2640 class_size += ik->transitive_interfaces()->size();
2641 // We do not have to count implementors, since we only store one!
2642 // SSS: How should these be accounted now that they have moved?
2643 // class_size += ik->fields()->length();
2644 }
2645 }
2646
2647 static void do_method(Method* m) {
2648 nmethods++;
2649 method_size += m->size();
2650 // class loader uses same objArray for empty vectors, so don't count these
2651 if (m->has_stackmap_table()) {
2652 method_size += m->stackmap_data()->size();
2653 }
2654
2655 MethodData* mdo = m->method_data();
2656 if (mdo != NULL) {
2657 nmethoddata++;
2658 methoddata_size += mdo->size();
2659 }
2660 }
2661
2662 public:
2663 static void print() {
2664 SystemDictionary::classes_do(do_class);
2665 SystemDictionary::methods_do(do_method);
2666 tty->print_cr("Class statistics:");
2667 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2668 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2669 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2670 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2671 }
2672 };
2673
2674
2675 int ClassStatistics::nclasses = 0;
2676 int ClassStatistics::nmethods = 0;
2677 int ClassStatistics::nmethoddata = 0;
2678 int ClassStatistics::class_size = 0;
2679 int ClassStatistics::method_size = 0;
2680 int ClassStatistics::debug_size = 0;
2681 int ClassStatistics::methoddata_size = 0;
2682
2683 void SystemDictionary::print_class_statistics() {
2684 ResourceMark rm;
2685 ClassStatistics::print();
2686 }
2687
2688
2689 class MethodStatistics: AllStatic {
2690 public:
2691 enum {
2692 max_parameter_size = 10
2693 };
2694 private:
2695
2696 static int _number_of_methods;
2697 static int _number_of_final_methods;
2698 static int _number_of_static_methods;
2699 static int _number_of_native_methods;
2700 static int _number_of_synchronized_methods;
2701 static int _number_of_profiled_methods;
2702 static int _number_of_bytecodes;
2703 static int _parameter_size_profile[max_parameter_size];
2704 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2705
2706 static void initialize() {
2707 _number_of_methods = 0;
2708 _number_of_final_methods = 0;
2709 _number_of_static_methods = 0;
2710 _number_of_native_methods = 0;
2711 _number_of_synchronized_methods = 0;
2712 _number_of_profiled_methods = 0;
2713 _number_of_bytecodes = 0;
2714 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2715 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2716 };
2717
2718 static void do_method(Method* m) {
2719 _number_of_methods++;
2720 // collect flag info
2721 if (m->is_final() ) _number_of_final_methods++;
2722 if (m->is_static() ) _number_of_static_methods++;
2723 if (m->is_native() ) _number_of_native_methods++;
2724 if (m->is_synchronized()) _number_of_synchronized_methods++;
2725 if (m->method_data() != NULL) _number_of_profiled_methods++;
2726 // collect parameter size info (add one for receiver, if any)
2727 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2728 // collect bytecodes info
2729 {
2730 Thread *thread = Thread::current();
2731 HandleMark hm(thread);
2732 BytecodeStream s(methodHandle(thread, m));
2733 Bytecodes::Code c;
2734 while ((c = s.next()) >= 0) {
2735 _number_of_bytecodes++;
2736 _bytecodes_profile[c]++;
2737 }
2738 }
2739 }
2740
2741 public:
2742 static void print() {
2743 initialize();
2744 SystemDictionary::methods_do(do_method);
2745 // generate output
2746 tty->cr();
2747 tty->print_cr("Method statistics (static):");
2748 // flag distribution
2749 tty->cr();
2750 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2751 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2752 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2753 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2754 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2755 // parameter size profile
2756 tty->cr();
2757 { int tot = 0;
2758 int avg = 0;
2759 for (int i = 0; i < max_parameter_size; i++) {
2760 int n = _parameter_size_profile[i];
2761 tot += n;
2762 avg += n*i;
2763 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2764 }
2765 assert(tot == _number_of_methods, "should be the same");
2766 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2767 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2768 }
2769 // bytecodes profile
2770 tty->cr();
2771 { int tot = 0;
2772 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2773 if (Bytecodes::is_defined(i)) {
2774 Bytecodes::Code c = Bytecodes::cast(i);
2775 int n = _bytecodes_profile[c];
2776 tot += n;
2777 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2778 }
2779 }
2780 assert(tot == _number_of_bytecodes, "should be the same");
2781 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2782 }
2783 tty->cr();
2784 }
2785 };
2786
2787 int MethodStatistics::_number_of_methods;
2788 int MethodStatistics::_number_of_final_methods;
2789 int MethodStatistics::_number_of_static_methods;
2790 int MethodStatistics::_number_of_native_methods;
2791 int MethodStatistics::_number_of_synchronized_methods;
2792 int MethodStatistics::_number_of_profiled_methods;
2793 int MethodStatistics::_number_of_bytecodes;
2794 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2795 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2796
2797
2798 void SystemDictionary::print_method_statistics() {
2799 MethodStatistics::print();
2800 }
2801
2802 #endif // PRODUCT