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/stringTable.hpp"
33 #include "classfile/systemDictionary.hpp"
34 #include "classfile/vmSymbols.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "interpreter/bytecodeStream.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "memory/filemap.hpp"
39 #include "memory/gcLocker.hpp"
40 #include "memory/oopFactory.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/instanceRefKlass.hpp"
43 #include "oops/klass.inline.hpp"
44 #include "oops/methodData.hpp"
45 #include "oops/objArrayKlass.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "oops/oop.inline2.hpp"
48 #include "oops/typeArrayKlass.hpp"
49 #include "prims/jvmtiEnvBase.hpp"
50 #include "prims/methodHandles.hpp"
51 #include "runtime/arguments.hpp"
52 #include "runtime/biasedLocking.hpp"
53 #include "runtime/fieldType.hpp"
54 #include "runtime/handles.inline.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/mutexLocker.hpp"
58 #include "runtime/orderAccess.inline.hpp"
59 #include "runtime/signature.hpp"
60 #include "services/classLoadingService.hpp"
61 #include "services/threadService.hpp"
62 #include "utilities/macros.hpp"
63 #include "utilities/ticks.hpp"
64 #if INCLUDE_CDS
65 #include "classfile/sharedClassUtil.hpp"
66 #include "classfile/systemDictionaryShared.hpp"
67 #endif
68 #if INCLUDE_TRACE
69 #include "trace/tracing.hpp"
70 #endif
71
72 Dictionary* SystemDictionary::_dictionary = NULL;
73 PlaceholderTable* SystemDictionary::_placeholders = NULL;
74 Dictionary* SystemDictionary::_shared_dictionary = NULL;
75 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
76 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
77 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
78
79
80 int SystemDictionary::_number_of_modifications = 0;
81 int SystemDictionary::_sdgeneration = 0;
82 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
83 20201,40423,99991};
84
85 oop SystemDictionary::_system_loader_lock_obj = NULL;
86
87 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
88 = { NULL /*, NULL...*/ };
89
90 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
91
92 oop SystemDictionary::_java_system_loader = NULL;
93
94 bool SystemDictionary::_has_loadClassInternal = false;
95 bool SystemDictionary::_has_checkPackageAccess = false;
96
97 // lazily initialized klass variables
98 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
99
100
101 // ----------------------------------------------------------------------------
102 // Java-level SystemLoader
103
104 oop SystemDictionary::java_system_loader() {
105 return _java_system_loader;
106 }
107
108 void SystemDictionary::compute_java_system_loader(TRAPS) {
109 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
110 JavaValue result(T_OBJECT);
111 JavaCalls::call_static(&result,
112 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
113 vmSymbols::getSystemClassLoader_name(),
114 vmSymbols::void_classloader_signature(),
115 CHECK);
116
117 _java_system_loader = (oop)result.get_jobject();
118
119 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
120 }
121
122
123 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
124 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
125 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
126 }
127
128 // ----------------------------------------------------------------------------
129 // debugging
130
131 #ifdef ASSERT
132
133 // return true if class_name contains no '.' (internal format is '/')
134 bool SystemDictionary::is_internal_format(Symbol* class_name) {
135 if (class_name != NULL) {
136 ResourceMark rm;
137 char* name = class_name->as_C_string();
138 return strchr(name, '.') == NULL;
139 } else {
140 return true;
141 }
142 }
143
144 #endif
145
146 // ----------------------------------------------------------------------------
147 // Parallel class loading check
148
149 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
150 if (UnsyncloadClass || class_loader.is_null()) return true;
151 if (AlwaysLockClassLoader) return false;
152 return java_lang_ClassLoader::parallelCapable(class_loader());
153 }
154 // ----------------------------------------------------------------------------
155 // ParallelDefineClass flag does not apply to bootclass loader
156 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
157 if (class_loader.is_null()) return false;
158 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
159 return true;
160 }
161 return false;
162 }
163
164 /**
165 * Returns true if the passed class loader is the extension class loader.
166 */
167 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
168 if (class_loader.is_null()) {
169 return false;
170 }
171 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
172 }
173
174 // ----------------------------------------------------------------------------
175 // Resolving of classes
176
177 // Forwards to resolve_or_null
178
179 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
180 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
181 if (HAS_PENDING_EXCEPTION || klass == NULL) {
182 KlassHandle k_h(THREAD, klass);
183 // can return a null klass
184 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
185 }
186 return klass;
187 }
188
189 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
190 bool throw_error,
191 KlassHandle klass_h, TRAPS) {
192 if (HAS_PENDING_EXCEPTION) {
193 // If we have a pending exception we forward it to the caller, unless throw_error is true,
194 // in which case we have to check whether the pending exception is a ClassNotFoundException,
195 // and if so convert it to a NoClassDefFoundError
196 // And chain the original ClassNotFoundException
197 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
198 ResourceMark rm(THREAD);
199 assert(klass_h() == NULL, "Should not have result with exception pending");
200 Handle e(THREAD, PENDING_EXCEPTION);
201 CLEAR_PENDING_EXCEPTION;
202 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
203 } else {
204 return NULL;
205 }
206 }
207 // Class not found, throw appropriate error or exception depending on value of throw_error
208 if (klass_h() == NULL) {
209 ResourceMark rm(THREAD);
210 if (throw_error) {
211 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
212 } else {
213 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
214 }
215 }
216 return (Klass*)klass_h();
217 }
218
219
220 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
221 bool throw_error, TRAPS)
222 {
223 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
224 }
225
226
227 // Forwards to resolve_instance_class_or_null
228
229 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
230 assert(!THREAD->is_Compiler_thread(),
231 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
232 class_name->as_C_string(),
233 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
234 if (FieldType::is_array(class_name)) {
235 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
236 } else if (FieldType::is_obj(class_name)) {
237 ResourceMark rm(THREAD);
238 // Ignore wrapping L and ;.
239 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
240 class_name->utf8_length() - 2, CHECK_NULL);
241 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
242 } else {
243 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
244 }
245 }
246
247 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
248 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
249 }
250
251 // Forwards to resolve_instance_class_or_null
252
253 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
254 Handle class_loader,
255 Handle protection_domain,
256 TRAPS) {
257 assert(FieldType::is_array(class_name), "must be array");
258 Klass* k = NULL;
259 FieldArrayInfo fd;
260 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
261 // of this call
262 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
263 if (t == T_OBJECT) {
264 // naked oop "k" is OK here -- we assign back into it
265 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
266 class_loader,
267 protection_domain,
268 CHECK_NULL);
269 if (k != NULL) {
270 k = k->array_klass(fd.dimension(), CHECK_NULL);
271 }
272 } else {
273 k = Universe::typeArrayKlassObj(t);
274 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
275 }
276 return k;
277 }
278
279
280 // Must be called for any super-class or super-interface resolution
281 // during class definition to allow class circularity checking
282 // super-interface callers:
283 // parse_interfaces - for defineClass & jvmtiRedefineClasses
284 // super-class callers:
285 // ClassFileParser - for defineClass & jvmtiRedefineClasses
286 // load_shared_class - while loading a class from shared archive
287 // resolve_instance_class_or_null:
288 // via: handle_parallel_super_load
289 // when resolving a class that has an existing placeholder with
290 // a saved superclass [i.e. a defineClass is currently in progress]
291 // if another thread is trying to resolve the class, it must do
292 // super-class checks on its own thread to catch class circularity
293 // This last call is critical in class circularity checking for cases
294 // where classloading is delegated to different threads and the
295 // classloader lock is released.
296 // Take the case: Base->Super->Base
297 // 1. If thread T1 tries to do a defineClass of class Base
298 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
299 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
300 // so it tries to load Super
301 // 3. If we load the class internally, or user classloader uses same thread
302 // loadClassFromxxx or defineClass via parseClassFile Super ...
303 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
304 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
305 // 3.4 calls resolve_super_or_fail Base
306 // 3.5 finds T1,Base -> throws class circularity
307 //OR 4. If T2 tries to resolve Super via defineClass Super ...
308 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
309 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
310 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
311 // 4.4 finds T2, Super -> throws class circularity
312 // Must be called, even if superclass is null, since this is
313 // where the placeholder entry is created which claims this
314 // thread is loading this class/classloader.
315 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
316 Symbol* class_name,
317 Handle class_loader,
318 Handle protection_domain,
319 bool is_superclass,
320 TRAPS) {
321 // Double-check, if child class is already loaded, just return super-class,interface
322 // Don't add a placedholder if already loaded, i.e. already in system dictionary
323 // Make sure there's a placeholder for the *child* before resolving.
324 // Used as a claim that this thread is currently loading superclass/classloader
325 // Used here for ClassCircularity checks and also for heap verification
326 // (every InstanceKlass in the heap needs to be in the system dictionary
327 // or have a placeholder).
328 // Must check ClassCircularity before checking if super class is already loaded
329 //
330 // We might not already have a placeholder if this child_name was
331 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
332 // the name of the class might not be known until the stream is actually
333 // parsed.
334 // Bugs 4643874, 4715493
335 // compute_hash can have a safepoint
336
337 ClassLoaderData* loader_data = class_loader_data(class_loader);
338 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
339 int d_index = dictionary()->hash_to_index(d_hash);
340 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
341 int p_index = placeholders()->hash_to_index(p_hash);
342 // can't throw error holding a lock
343 bool child_already_loaded = false;
344 bool throw_circularity_error = false;
345 {
346 MutexLocker mu(SystemDictionary_lock, THREAD);
347 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
348 Klass* quicksuperk;
349 // to support // loading: if child done loading, just return superclass
350 // if class_name, & class_loader don't match:
351 // if initial define, SD update will give LinkageError
352 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
353 // so we don't throw an exception here.
354 // see: nsk redefclass014 & java.lang.instrument Instrument032
355 if ((childk != NULL ) && (is_superclass) &&
356 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
357
358 ((quicksuperk->name() == class_name) &&
359 (quicksuperk->class_loader() == class_loader()))) {
360 return quicksuperk;
361 } else {
362 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
363 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
364 throw_circularity_error = true;
365 }
366 }
367 if (!throw_circularity_error) {
368 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
369 }
370 }
371 if (throw_circularity_error) {
372 ResourceMark rm(THREAD);
373 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
374 }
375
376 // java.lang.Object should have been found above
377 assert(class_name != NULL, "null super class for resolving");
378 // Resolve the super class or interface, check results on return
379 Klass* superk = SystemDictionary::resolve_or_null(class_name,
380 class_loader,
381 protection_domain,
382 THREAD);
383
384 KlassHandle superk_h(THREAD, superk);
385
386 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
387 // It is no longer necessary to keep the placeholder table alive until update_dictionary
388 // or error. GC used to walk the placeholder table as strong roots.
389 // The instanceKlass is kept alive because the class loader is on the stack,
390 // which keeps the loader_data alive, as well as all instanceKlasses in
391 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
392 {
393 MutexLocker mu(SystemDictionary_lock, THREAD);
394 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
395 SystemDictionary_lock->notify_all();
396 }
397 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
398 // can null superk
399 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
400 }
401
402 return superk_h();
403 }
404
405 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
406 Handle class_loader,
407 Handle protection_domain,
408 TRAPS) {
409 if(!has_checkPackageAccess()) return;
410
411 // Now we have to call back to java to check if the initating class has access
412 JavaValue result(T_VOID);
413 if (TraceProtectionDomainVerification) {
414 // Print out trace information
415 tty->print_cr("Checking package access");
416 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
417 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
418 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
419 }
420
421 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
422 JavaCalls::call_special(&result,
423 class_loader,
424 system_loader,
425 vmSymbols::checkPackageAccess_name(),
426 vmSymbols::class_protectiondomain_signature(),
427 Handle(THREAD, klass->java_mirror()),
428 protection_domain,
429 THREAD);
430
431 if (TraceProtectionDomainVerification) {
432 if (HAS_PENDING_EXCEPTION) {
433 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
434 } else {
435 tty->print_cr(" -> granted");
436 }
437 tty->cr();
438 }
439
440 if (HAS_PENDING_EXCEPTION) return;
441
442 // If no exception has been thrown, we have validated the protection domain
443 // Insert the protection domain of the initiating class into the set.
444 {
445 // We recalculate the entry here -- we've called out to java since
446 // the last time it was calculated.
447 ClassLoaderData* loader_data = class_loader_data(class_loader);
448
449 Symbol* kn = klass->name();
450 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
451 int d_index = dictionary()->hash_to_index(d_hash);
452
453 MutexLocker mu(SystemDictionary_lock, THREAD);
454 {
455 // Note that we have an entry, and entries can be deleted only during GC,
456 // so we cannot allow GC to occur while we're holding this entry.
457
458 // We're using a No_Safepoint_Verifier to catch any place where we
459 // might potentially do a GC at all.
460 // Dictionary::do_unloading() asserts that classes in SD are only
461 // unloaded at a safepoint. Anonymous classes are not in SD.
462 No_Safepoint_Verifier nosafepoint;
463 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
464 protection_domain, THREAD);
465 }
466 }
467 }
468
469 // We only get here if this thread finds that another thread
470 // has already claimed the placeholder token for the current operation,
471 // but that other thread either never owned or gave up the
472 // object lock
473 // Waits on SystemDictionary_lock to indicate placeholder table updated
474 // On return, caller must recheck placeholder table state
475 //
476 // We only get here if
477 // 1) custom classLoader, i.e. not bootstrap classloader
478 // 2) UnsyncloadClass not set
479 // 3) custom classLoader has broken the class loader objectLock
480 // so another thread got here in parallel
481 //
482 // lockObject must be held.
483 // Complicated dance due to lock ordering:
484 // Must first release the classloader object lock to
485 // allow initial definer to complete the class definition
486 // and to avoid deadlock
487 // Reclaim classloader lock object with same original recursion count
488 // Must release SystemDictionary_lock after notify, since
489 // class loader lock must be claimed before SystemDictionary_lock
490 // to prevent deadlocks
491 //
492 // The notify allows applications that did an untimed wait() on
493 // the classloader object lock to not hang.
494 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
495 assert_lock_strong(SystemDictionary_lock);
496
497 bool calledholdinglock
498 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
499 assert(calledholdinglock,"must hold lock for notify");
500 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
501 ObjectSynchronizer::notifyall(lockObject, THREAD);
502 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
503 SystemDictionary_lock->wait();
504 SystemDictionary_lock->unlock();
505 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
506 SystemDictionary_lock->lock();
507 }
508
509 // If the class in is in the placeholder table, class loading is in progress
510 // For cases where the application changes threads to load classes, it
511 // is critical to ClassCircularity detection that we try loading
512 // the superclass on the same thread internally, so we do parallel
513 // super class loading here.
514 // This also is critical in cases where the original thread gets stalled
515 // even in non-circularity situations.
516 // Note: must call resolve_super_or_fail even if null super -
517 // to force placeholder entry creation for this class for circularity detection
518 // Caller must check for pending exception
519 // Returns non-null Klass* if other thread has completed load
520 // and we are done,
521 // If return null Klass* and no pending exception, the caller must load the class
522 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
523 Symbol* name, Symbol* superclassname, Handle class_loader,
524 Handle protection_domain, Handle lockObject, TRAPS) {
525
526 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
527 ClassLoaderData* loader_data = class_loader_data(class_loader);
528 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
529 int d_index = dictionary()->hash_to_index(d_hash);
530 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
531 int p_index = placeholders()->hash_to_index(p_hash);
532
533 // superk is not used, resolve_super called for circularity check only
534 // This code is reached in two situations. One if this thread
535 // is loading the same class twice (e.g. ClassCircularity, or
536 // java.lang.instrument).
537 // The second is if another thread started the resolve_super first
538 // and has not yet finished.
539 // In both cases the original caller will clean up the placeholder
540 // entry on error.
541 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
542 superclassname,
543 class_loader,
544 protection_domain,
545 true,
546 CHECK_(nh));
547
548 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
549 // Serial class loaders and bootstrap classloader do wait for superclass loads
550 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
551 MutexLocker mu(SystemDictionary_lock, THREAD);
552 // Check if classloading completed while we were loading superclass or waiting
553 Klass* check = find_class(d_index, d_hash, name, loader_data);
554 if (check != NULL) {
555 // Klass is already loaded, so just return it
556 return(instanceKlassHandle(THREAD, check));
557 } else {
558 return nh;
559 }
560 }
561
562 // must loop to both handle other placeholder updates
563 // and spurious notifications
564 bool super_load_in_progress = true;
565 PlaceholderEntry* placeholder;
566 while (super_load_in_progress) {
567 MutexLocker mu(SystemDictionary_lock, THREAD);
568 // Check if classloading completed while we were loading superclass or waiting
569 Klass* check = find_class(d_index, d_hash, name, loader_data);
570 if (check != NULL) {
571 // Klass is already loaded, so just return it
572 return(instanceKlassHandle(THREAD, check));
573 } else {
574 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
575 if (placeholder && placeholder->super_load_in_progress() ){
576 // Before UnsyncloadClass:
577 // We only get here if the application has released the
578 // classloader lock when another thread was in the middle of loading a
579 // superclass/superinterface for this class, and now
580 // this thread is also trying to load this class.
581 // To minimize surprises, the first thread that started to
582 // load a class should be the one to complete the loading
583 // with the classfile it initially expected.
584 // This logic has the current thread wait once it has done
585 // all the superclass/superinterface loading it can, until
586 // the original thread completes the class loading or fails
587 // If it completes we will use the resulting InstanceKlass
588 // which we will find below in the systemDictionary.
589 // We also get here for parallel bootstrap classloader
590 if (class_loader.is_null()) {
591 SystemDictionary_lock->wait();
592 } else {
593 double_lock_wait(lockObject, THREAD);
594 }
595 } else {
596 // If not in SD and not in PH, other thread's load must have failed
597 super_load_in_progress = false;
598 }
599 }
600 }
601 return (nh);
602 }
603
604
605 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
606 Handle class_loader,
607 Handle protection_domain,
608 TRAPS) {
609 assert(name != NULL && !FieldType::is_array(name) &&
610 !FieldType::is_obj(name), "invalid class name");
611
612 Ticks class_load_start_time = Ticks::now();
613
614 // Fix for 4474172; see evaluation for more details
615 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
616 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
617
618 // Do lookup to see if class already exist and the protection domain
619 // has the right access
620 // This call uses find which checks protection domain already matches
621 // All subsequent calls use find_class, and set has_loaded_class so that
622 // before we return a result we call out to java to check for valid protection domain
623 // to allow returning the Klass* and add it to the pd_set if it is valid
624 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
625 int d_index = dictionary()->hash_to_index(d_hash);
626 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
627 protection_domain, THREAD);
628 if (probe != NULL) return probe;
629
630
631 // Non-bootstrap class loaders will call out to class loader and
632 // define via jvm/jni_DefineClass which will acquire the
633 // class loader object lock to protect against multiple threads
634 // defining the class in parallel by accident.
635 // This lock must be acquired here so the waiter will find
636 // any successful result in the SystemDictionary and not attempt
637 // the define
638 // ParallelCapable Classloaders and the bootstrap classloader,
639 // or all classloaders with UnsyncloadClass do not acquire lock here
640 bool DoObjectLock = true;
641 if (is_parallelCapable(class_loader)) {
642 DoObjectLock = false;
643 }
644
645 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
646 int p_index = placeholders()->hash_to_index(p_hash);
647
648 // Class is not in SystemDictionary so we have to do loading.
649 // Make sure we are synchronized on the class loader before we proceed
650 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
651 check_loader_lock_contention(lockObject, THREAD);
652 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
653
654 // Check again (after locking) if class already exist in SystemDictionary
655 bool class_has_been_loaded = false;
656 bool super_load_in_progress = false;
657 bool havesupername = false;
658 instanceKlassHandle k;
659 PlaceholderEntry* placeholder;
660 Symbol* superclassname = NULL;
661
662 {
663 MutexLocker mu(SystemDictionary_lock, THREAD);
664 Klass* check = find_class(d_index, d_hash, name, loader_data);
665 if (check != NULL) {
666 // Klass is already loaded, so just return it
667 class_has_been_loaded = true;
668 k = instanceKlassHandle(THREAD, check);
669 } else {
670 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
671 if (placeholder && placeholder->super_load_in_progress()) {
672 super_load_in_progress = true;
673 if (placeholder->havesupername() == true) {
674 superclassname = placeholder->supername();
675 havesupername = true;
676 }
677 }
678 }
679 }
680
681 // If the class is in the placeholder table, class loading is in progress
682 if (super_load_in_progress && havesupername==true) {
683 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
684 class_loader, protection_domain, lockObject, THREAD);
685 if (HAS_PENDING_EXCEPTION) {
686 return NULL;
687 }
688 if (!k.is_null()) {
689 class_has_been_loaded = true;
690 }
691 }
692
693 bool throw_circularity_error = false;
694 if (!class_has_been_loaded) {
695 bool load_instance_added = false;
696
697 // add placeholder entry to record loading instance class
698 // Five cases:
699 // All cases need to prevent modifying bootclasssearchpath
700 // in parallel with a classload of same classname
701 // Redefineclasses uses existence of the placeholder for the duration
702 // of the class load to prevent concurrent redefinition of not completely
703 // defined classes.
704 // case 1. traditional classloaders that rely on the classloader object lock
705 // - no other need for LOAD_INSTANCE
706 // case 2. traditional classloaders that break the classloader object lock
707 // as a deadlock workaround. Detection of this case requires that
708 // this check is done while holding the classloader object lock,
709 // and that lock is still held when calling classloader's loadClass.
710 // For these classloaders, we ensure that the first requestor
711 // completes the load and other requestors wait for completion.
712 // case 3. UnsyncloadClass - don't use objectLocker
713 // With this flag, we allow parallel classloading of a
714 // class/classloader pair
715 // case4. Bootstrap classloader - don't own objectLocker
716 // This classloader supports parallelism at the classloader level,
717 // but only allows a single load of a class/classloader pair.
718 // No performance benefit and no deadlock issues.
719 // case 5. parallelCapable user level classloaders - without objectLocker
720 // Allow parallel classloading of a class/classloader pair
721
722 {
723 MutexLocker mu(SystemDictionary_lock, THREAD);
724 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
725 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
726 if (oldprobe) {
727 // only need check_seen_thread once, not on each loop
728 // 6341374 java/lang/Instrument with -Xcomp
729 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
730 throw_circularity_error = true;
731 } else {
732 // case 1: traditional: should never see load_in_progress.
733 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
734
735 // case 4: bootstrap classloader: prevent futile classloading,
736 // wait on first requestor
737 if (class_loader.is_null()) {
738 SystemDictionary_lock->wait();
739 } else {
740 // case 2: traditional with broken classloader lock. wait on first
741 // requestor.
742 double_lock_wait(lockObject, THREAD);
743 }
744 // Check if classloading completed while we were waiting
745 Klass* check = find_class(d_index, d_hash, name, loader_data);
746 if (check != NULL) {
747 // Klass is already loaded, so just return it
748 k = instanceKlassHandle(THREAD, check);
749 class_has_been_loaded = true;
750 }
751 // check if other thread failed to load and cleaned up
752 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
753 }
754 }
755 }
756 }
757 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
758 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
759 // LOAD_INSTANCE in parallel
760
761 if (!throw_circularity_error && !class_has_been_loaded) {
762 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
763 load_instance_added = true;
764 // For class loaders that do not acquire the classloader object lock,
765 // if they did not catch another thread holding LOAD_INSTANCE,
766 // need a check analogous to the acquire ObjectLocker/find_class
767 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
768 // one final check if the load has already completed
769 // class loaders holding the ObjectLock shouldn't find the class here
770 Klass* check = find_class(d_index, d_hash, name, loader_data);
771 if (check != NULL) {
772 // Klass is already loaded, so return it after checking/adding protection domain
773 k = instanceKlassHandle(THREAD, check);
774 class_has_been_loaded = true;
775 }
776 }
777 }
778
779 // must throw error outside of owning lock
780 if (throw_circularity_error) {
781 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
782 ResourceMark rm(THREAD);
783 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
784 }
785
786 if (!class_has_been_loaded) {
787
788 // Do actual loading
789 k = load_instance_class(name, class_loader, THREAD);
790
791 // For UnsyncloadClass only
792 // If they got a linkageError, check if a parallel class load succeeded.
793 // If it did, then for bytecode resolution the specification requires
794 // that we return the same result we did for the other thread, i.e. the
795 // successfully loaded InstanceKlass
796 // Should not get here for classloaders that support parallelism
797 // with the new cleaner mechanism, even with AllowParallelDefineClass
798 // Bootstrap goes through here to allow for an extra guarantee check
799 if (UnsyncloadClass || (class_loader.is_null())) {
800 if (k.is_null() && HAS_PENDING_EXCEPTION
801 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
802 MutexLocker mu(SystemDictionary_lock, THREAD);
803 Klass* check = find_class(d_index, d_hash, name, loader_data);
804 if (check != NULL) {
805 // Klass is already loaded, so just use it
806 k = instanceKlassHandle(THREAD, check);
807 CLEAR_PENDING_EXCEPTION;
808 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
809 }
810 }
811 }
812
813 // If everything was OK (no exceptions, no null return value), and
814 // class_loader is NOT the defining loader, do a little more bookkeeping.
815 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
816 k->class_loader() != class_loader()) {
817
818 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
819
820 // Need to check for a PENDING_EXCEPTION again; check_constraints
821 // can throw and doesn't use the CHECK macro.
822 if (!HAS_PENDING_EXCEPTION) {
823 { // Grabbing the Compile_lock prevents systemDictionary updates
824 // during compilations.
825 MutexLocker mu(Compile_lock, THREAD);
826 update_dictionary(d_index, d_hash, p_index, p_hash,
827 k, class_loader, THREAD);
828 }
829
830 if (JvmtiExport::should_post_class_load()) {
831 Thread *thread = THREAD;
832 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
833 JvmtiExport::post_class_load((JavaThread *) thread, k());
834 }
835 }
836 }
837 } // load_instance_class loop
838
839 if (load_instance_added == true) {
840 // clean up placeholder entries for LOAD_INSTANCE success or error
841 // This brackets the SystemDictionary updates for both defining
842 // and initiating loaders
843 MutexLocker mu(SystemDictionary_lock, THREAD);
844 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
845 SystemDictionary_lock->notify_all();
846 }
847 }
848
849 if (HAS_PENDING_EXCEPTION || k.is_null()) {
850 return NULL;
851 }
852
853 post_class_load_event(class_load_start_time, k, class_loader);
854
855 #ifdef ASSERT
856 {
857 ClassLoaderData* loader_data = k->class_loader_data();
858 MutexLocker mu(SystemDictionary_lock, THREAD);
859 Klass* kk = find_class(name, loader_data);
860 assert(kk == k(), "should be present in dictionary");
861 }
862 #endif
863
864 // return if the protection domain in NULL
865 if (protection_domain() == NULL) return k();
866
867 // Check the protection domain has the right access
868 {
869 MutexLocker mu(SystemDictionary_lock, THREAD);
870 // Note that we have an entry, and entries can be deleted only during GC,
871 // so we cannot allow GC to occur while we're holding this entry.
872 // We're using a No_Safepoint_Verifier to catch any place where we
873 // might potentially do a GC at all.
874 // Dictionary::do_unloading() asserts that classes in SD are only
875 // unloaded at a safepoint. Anonymous classes are not in SD.
876 No_Safepoint_Verifier nosafepoint;
877 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
878 loader_data,
879 protection_domain)) {
880 return k();
881 }
882 }
883
884 // Verify protection domain. If it fails an exception is thrown
885 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
886
887 return k();
888 }
889
890
891 // This routine does not lock the system dictionary.
892 //
893 // Since readers don't hold a lock, we must make sure that system
894 // dictionary entries are only removed at a safepoint (when only one
895 // thread is running), and are added to in a safe way (all links must
896 // be updated in an MT-safe manner).
897 //
898 // Callers should be aware that an entry could be added just after
899 // _dictionary->bucket(index) is read here, so the caller will not see
900 // the new entry.
901
902 Klass* SystemDictionary::find(Symbol* class_name,
903 Handle class_loader,
904 Handle protection_domain,
905 TRAPS) {
906
907 // The result of this call should be consistent with the result
908 // of the call to resolve_instance_class_or_null().
909 // See evaluation 6790209 and 4474172 for more details.
910 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
911 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
912
913 if (loader_data == NULL) {
914 // If the ClassLoaderData has not been setup,
915 // then the class loader has no entries in the dictionary.
916 return NULL;
917 }
918
919 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
920 int d_index = dictionary()->hash_to_index(d_hash);
921
922 {
923 // Note that we have an entry, and entries can be deleted only during GC,
924 // so we cannot allow GC to occur while we're holding this entry.
925 // We're using a No_Safepoint_Verifier to catch any place where we
926 // might potentially do a GC at all.
927 // Dictionary::do_unloading() asserts that classes in SD are only
928 // unloaded at a safepoint. Anonymous classes are not in SD.
929 No_Safepoint_Verifier nosafepoint;
930 return dictionary()->find(d_index, d_hash, class_name, loader_data,
931 protection_domain, THREAD);
932 }
933 }
934
935
936 // Look for a loaded instance or array klass by name. Do not do any loading.
937 // return NULL in case of error.
938 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
939 Handle class_loader,
940 Handle protection_domain,
941 TRAPS) {
942 Klass* k = NULL;
943 assert(class_name != NULL, "class name must be non NULL");
944
945 if (FieldType::is_array(class_name)) {
946 // The name refers to an array. Parse the name.
947 // dimension and object_key in FieldArrayInfo are assigned as a
948 // side-effect of this call
949 FieldArrayInfo fd;
950 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
951 if (t != T_OBJECT) {
952 k = Universe::typeArrayKlassObj(t);
953 } else {
954 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
955 }
956 if (k != NULL) {
957 k = k->array_klass_or_null(fd.dimension());
958 }
959 } else {
960 k = find(class_name, class_loader, protection_domain, THREAD);
961 }
962 return k;
963 }
964
965 // Note: this method is much like resolve_from_stream, but
966 // updates no supplemental data structures.
967 // TODO consolidate the two methods with a helper routine?
968 Klass* SystemDictionary::parse_stream(Symbol* class_name,
969 Handle class_loader,
970 Handle protection_domain,
971 ClassFileStream* st,
972 KlassHandle host_klass,
973 GrowableArray<Handle>* cp_patches,
974 TRAPS) {
975 TempNewSymbol parsed_name = NULL;
976
977 Ticks class_load_start_time = Ticks::now();
978
979 ClassLoaderData* loader_data;
980 if (host_klass.not_null()) {
981 // Create a new CLD for anonymous class, that uses the same class loader
982 // as the host_klass
983 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
984 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
985 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
986 loader_data->record_dependency(host_klass(), CHECK_NULL);
987 } else {
988 loader_data = ClassLoaderData::class_loader_data(class_loader());
989 }
990
991 // Parse the stream. Note that we do this even though this klass might
992 // already be present in the SystemDictionary, otherwise we would not
993 // throw potential ClassFormatErrors.
994 //
995 // Note: "name" is updated.
996
997 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
998 loader_data,
999 protection_domain,
1000 host_klass,
1001 cp_patches,
1002 parsed_name,
1003 true,
1004 THREAD);
1005
1006
1007 if (host_klass.not_null() && k.not_null()) {
1008 // If it's anonymous, initialize it now, since nobody else will.
1009
1010 {
1011 MutexLocker mu_r(Compile_lock, THREAD);
1012
1013 // Add to class hierarchy, initialize vtables, and do possible
1014 // deoptimizations.
1015 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1016
1017 // But, do not add to system dictionary.
1018
1019 // compiled code dependencies need to be validated anyway
1020 notice_modification();
1021 }
1022
1023 // Rewrite and patch constant pool here.
1024 k->link_class(CHECK_NULL);
1025 if (cp_patches != NULL) {
1026 k->constants()->patch_resolved_references(cp_patches);
1027 }
1028 k->eager_initialize(CHECK_NULL);
1029
1030 // notify jvmti
1031 if (JvmtiExport::should_post_class_load()) {
1032 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1033 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1034 }
1035
1036 post_class_load_event(class_load_start_time, k, class_loader);
1037 }
1038 assert(host_klass.not_null() || cp_patches == NULL,
1039 "cp_patches only found with host_klass");
1040
1041 return k();
1042 }
1043
1044 // Add a klass to the system from a stream (called by jni_DefineClass and
1045 // JVM_DefineClass).
1046 // Note: class_name can be NULL. In that case we do not know the name of
1047 // the class until we have parsed the stream.
1048
1049 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1050 Handle class_loader,
1051 Handle protection_domain,
1052 ClassFileStream* st,
1053 bool verify,
1054 TRAPS) {
1055
1056 // Classloaders that support parallelism, e.g. bootstrap classloader,
1057 // or all classloaders with UnsyncloadClass do not acquire lock here
1058 bool DoObjectLock = true;
1059 if (is_parallelCapable(class_loader)) {
1060 DoObjectLock = false;
1061 }
1062
1063 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1064
1065 // Make sure we are synchronized on the class loader before we proceed
1066 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1067 check_loader_lock_contention(lockObject, THREAD);
1068 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1069
1070 TempNewSymbol parsed_name = NULL;
1071
1072 // Parse the stream. Note that we do this even though this klass might
1073 // already be present in the SystemDictionary, otherwise we would not
1074 // throw potential ClassFormatErrors.
1075 //
1076 // Note: "name" is updated.
1077
1078 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1079 loader_data,
1080 protection_domain,
1081 parsed_name,
1082 verify,
1083 THREAD);
1084
1085 const char* pkg = "java/";
1086 if (!HAS_PENDING_EXCEPTION &&
1087 !class_loader.is_null() &&
1088 parsed_name != NULL &&
1089 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1090 // It is illegal to define classes in the "java." package from
1091 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1092 ResourceMark rm(THREAD);
1093 char* name = parsed_name->as_C_string();
1094 char* index = strrchr(name, '/');
1095 *index = '\0'; // chop to just the package name
1096 while ((index = strchr(name, '/')) != NULL) {
1097 *index = '.'; // replace '/' with '.' in package name
1098 }
1099 const char* fmt = "Prohibited package name: %s";
1100 size_t len = strlen(fmt) + strlen(name);
1101 char* message = NEW_RESOURCE_ARRAY(char, len);
1102 jio_snprintf(message, len, fmt, name);
1103 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1104 vmSymbols::java_lang_SecurityException(), message);
1105 }
1106
1107 if (!HAS_PENDING_EXCEPTION) {
1108 assert(parsed_name != NULL, "Sanity");
1109 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1110 // Verification prevents us from creating names with dots in them, this
1111 // asserts that that's the case.
1112 assert(is_internal_format(parsed_name),
1113 "external class name format used internally");
1114
1115 // Add class just loaded
1116 // If a class loader supports parallel classloading handle parallel define requests
1117 // find_or_define_instance_class may return a different InstanceKlass
1118 if (is_parallelCapable(class_loader)) {
1119 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1120 } else {
1121 define_instance_class(k, THREAD);
1122 }
1123 }
1124
1125 // Make sure we have an entry in the SystemDictionary on success
1126 debug_only( {
1127 if (!HAS_PENDING_EXCEPTION) {
1128 assert(parsed_name != NULL, "parsed_name is still null?");
1129 Symbol* h_name = k->name();
1130 ClassLoaderData *defining_loader_data = k->class_loader_data();
1131
1132 MutexLocker mu(SystemDictionary_lock, THREAD);
1133
1134 Klass* check = find_class(parsed_name, loader_data);
1135 assert(check == k(), "should be present in the dictionary");
1136
1137 Klass* check2 = find_class(h_name, defining_loader_data);
1138 assert(check == check2, "name inconsistancy in SystemDictionary");
1139 }
1140 } );
1141
1142 return k();
1143 }
1144
1145 #if INCLUDE_CDS
1146 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1147 int number_of_entries) {
1148 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1149 "bad shared dictionary size.");
1150 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1151 }
1152
1153
1154 // If there is a shared dictionary, then find the entry for the
1155 // given shared system class, if any.
1156
1157 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1158 if (shared_dictionary() != NULL) {
1159 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1160 int d_index = shared_dictionary()->hash_to_index(d_hash);
1161
1162 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1163 } else {
1164 return NULL;
1165 }
1166 }
1167
1168
1169 // Load a class from the shared spaces (found through the shared system
1170 // dictionary). Force the superclass and all interfaces to be loaded.
1171 // Update the class definition to include sibling classes and no
1172 // subclasses (yet). [Classes in the shared space are not part of the
1173 // object hierarchy until loaded.]
1174
1175 instanceKlassHandle SystemDictionary::load_shared_class(
1176 Symbol* class_name, Handle class_loader, TRAPS) {
1177 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1178 // Make sure we only return the boot class for the NULL classloader.
1179 if (ik.not_null() &&
1180 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1181 Handle protection_domain;
1182 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1183 }
1184 return instanceKlassHandle();
1185 }
1186
1187 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1188 Handle class_loader,
1189 Handle protection_domain, TRAPS) {
1190 if (ik.not_null()) {
1191 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1192 Symbol* class_name = ik->name();
1193
1194 // Found the class, now load the superclass and interfaces. If they
1195 // are shared, add them to the main system dictionary and reset
1196 // their hierarchy references (supers, subs, and interfaces).
1197
1198 if (ik->super() != NULL) {
1199 Symbol* cn = ik->super()->name();
1200 resolve_super_or_fail(class_name, cn,
1201 class_loader, protection_domain, true, CHECK_(nh));
1202 }
1203
1204 Array<Klass*>* interfaces = ik->local_interfaces();
1205 int num_interfaces = interfaces->length();
1206 for (int index = 0; index < num_interfaces; index++) {
1207 Klass* k = interfaces->at(index);
1208
1209 // Note: can not use InstanceKlass::cast here because
1210 // interfaces' InstanceKlass's C++ vtbls haven't been
1211 // reinitialized yet (they will be once the interface classes
1212 // are loaded)
1213 Symbol* name = k->name();
1214 resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1215 }
1216
1217 // Adjust methods to recover missing data. They need addresses for
1218 // interpreter entry points and their default native method address
1219 // must be reset.
1220
1221 // Updating methods must be done under a lock so multiple
1222 // threads don't update these in parallel
1223 //
1224 // Shared classes are all currently loaded by either the bootstrap or
1225 // internal parallel class loaders, so this will never cause a deadlock
1226 // on a custom class loader lock.
1227
1228 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1229 {
1230 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1231 check_loader_lock_contention(lockObject, THREAD);
1232 ObjectLocker ol(lockObject, THREAD, true);
1233 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1234 }
1235
1236 if (TraceClassLoading) {
1237 ResourceMark rm;
1238 tty->print("[Loaded %s", ik->external_name());
1239 tty->print(" from shared objects file");
1240 if (class_loader.not_null()) {
1241 tty->print(" by %s", loader_data->loader_name());
1242 }
1243 tty->print_cr("]");
1244 }
1245
1246 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1247 // Only dump the classes that can be stored into CDS archive
1248 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1249 ResourceMark rm(THREAD);
1250 classlist_file->print_cr("%s", ik->name()->as_C_string());
1251 classlist_file->flush();
1252 }
1253 }
1254
1255 // notify a class loaded from shared object
1256 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1257 true /* shared class */);
1258 }
1259 return ik;
1260 }
1261 #endif // INCLUDE_CDS
1262
1263 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1264 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1265 if (class_loader.is_null()) {
1266
1267 // Search the shared system dictionary for classes preloaded into the
1268 // shared spaces.
1269 instanceKlassHandle k;
1270 {
1271 #if INCLUDE_CDS
1272 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1273 k = load_shared_class(class_name, class_loader, THREAD);
1274 #endif
1275 }
1276
1277 if (k.is_null()) {
1278 // Use VM class loader
1279 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1280 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1281 }
1282
1283 // find_or_define_instance_class may return a different InstanceKlass
1284 if (!k.is_null()) {
1285 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1286 }
1287 return k;
1288 } else {
1289 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1290 ResourceMark rm(THREAD);
1291
1292 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1293 JavaThread* jt = (JavaThread*) THREAD;
1294
1295 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1296 ClassLoader::perf_app_classload_selftime(),
1297 ClassLoader::perf_app_classload_count(),
1298 jt->get_thread_stat()->perf_recursion_counts_addr(),
1299 jt->get_thread_stat()->perf_timers_addr(),
1300 PerfClassTraceTime::CLASS_LOAD);
1301
1302 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1303 // Translate to external class name format, i.e., convert '/' chars to '.'
1304 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1305
1306 JavaValue result(T_OBJECT);
1307
1308 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1309
1310 // Call public unsynchronized loadClass(String) directly for all class loaders
1311 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1312 // acquire a class-name based lock rather than the class loader object lock.
1313 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1314 // so the call to loadClassInternal() was not required.
1315 //
1316 // UnsyncloadClass flag means both call loadClass(String) and do
1317 // not acquire the class loader lock even for class loaders that are
1318 // not parallelCapable. This was a risky transitional
1319 // flag for diagnostic purposes only. It is risky to call
1320 // custom class loaders without synchronization.
1321 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1322 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1323 // Do NOT assume this will be supported in future releases.
1324 //
1325 // Added MustCallLoadClassInternal in case we discover in the field
1326 // a customer that counts on this call
1327 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1328 JavaCalls::call_special(&result,
1329 class_loader,
1330 spec_klass,
1331 vmSymbols::loadClassInternal_name(),
1332 vmSymbols::string_class_signature(),
1333 string,
1334 CHECK_(nh));
1335 } else {
1336 JavaCalls::call_virtual(&result,
1337 class_loader,
1338 spec_klass,
1339 vmSymbols::loadClass_name(),
1340 vmSymbols::string_class_signature(),
1341 string,
1342 CHECK_(nh));
1343 }
1344
1345 assert(result.get_type() == T_OBJECT, "just checking");
1346 oop obj = (oop) result.get_jobject();
1347
1348 // Primitive classes return null since forName() can not be
1349 // used to obtain any of the Class objects representing primitives or void
1350 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1351 instanceKlassHandle k =
1352 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1353 // For user defined Java class loaders, check that the name returned is
1354 // the same as that requested. This check is done for the bootstrap
1355 // loader when parsing the class file.
1356 if (class_name == k->name()) {
1357 return k;
1358 }
1359 }
1360 // Class is not found or has the wrong name, return NULL
1361 return nh;
1362 }
1363 }
1364
1365 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1366
1367 ClassLoaderData* loader_data = k->class_loader_data();
1368 Handle class_loader_h(THREAD, loader_data->class_loader());
1369
1370 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1371
1372 // for bootstrap and other parallel classloaders don't acquire lock,
1373 // use placeholder token
1374 // If a parallelCapable class loader calls define_instance_class instead of
1375 // find_or_define_instance_class to get here, we have a timing
1376 // hole with systemDictionary updates and check_constraints
1377 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1378 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1379 compute_loader_lock_object(class_loader_h, THREAD)),
1380 "define called without lock");
1381 }
1382
1383 // Check class-loading constraints. Throw exception if violation is detected.
1384 // Grabs and releases SystemDictionary_lock
1385 // The check_constraints/find_class call and update_dictionary sequence
1386 // must be "atomic" for a specific class/classloader pair so we never
1387 // define two different instanceKlasses for that class/classloader pair.
1388 // Existing classloaders will call define_instance_class with the
1389 // classloader lock held
1390 // Parallel classloaders will call find_or_define_instance_class
1391 // which will require a token to perform the define class
1392 Symbol* name_h = k->name();
1393 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1394 int d_index = dictionary()->hash_to_index(d_hash);
1395 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1396
1397 // Register class just loaded with class loader (placed in Vector)
1398 // Note we do this before updating the dictionary, as this can
1399 // fail with an OutOfMemoryError (if it does, we will *not* put this
1400 // class in the dictionary and will not update the class hierarchy).
1401 // JVMTI FollowReferences needs to find the classes this way.
1402 if (k->class_loader() != NULL) {
1403 methodHandle m(THREAD, Universe::loader_addClass_method());
1404 JavaValue result(T_VOID);
1405 JavaCallArguments args(class_loader_h);
1406 args.push_oop(Handle(THREAD, k->java_mirror()));
1407 JavaCalls::call(&result, m, &args, CHECK);
1408 }
1409
1410 // Add the new class. We need recompile lock during update of CHA.
1411 {
1412 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1413 int p_index = placeholders()->hash_to_index(p_hash);
1414
1415 MutexLocker mu_r(Compile_lock, THREAD);
1416
1417 // Add to class hierarchy, initialize vtables, and do possible
1418 // deoptimizations.
1419 add_to_hierarchy(k, CHECK); // No exception, but can block
1420
1421 // Add to systemDictionary - so other classes can see it.
1422 // Grabs and releases SystemDictionary_lock
1423 update_dictionary(d_index, d_hash, p_index, p_hash,
1424 k, class_loader_h, THREAD);
1425 }
1426 k->eager_initialize(THREAD);
1427
1428 // notify jvmti
1429 if (JvmtiExport::should_post_class_load()) {
1430 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1431 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1432
1433 }
1434
1435 }
1436
1437 // Support parallel classloading
1438 // All parallel class loaders, including bootstrap classloader
1439 // lock a placeholder entry for this class/class_loader pair
1440 // to allow parallel defines of different classes for this class loader
1441 // With AllowParallelDefine flag==true, in case they do not synchronize around
1442 // FindLoadedClass/DefineClass, calls, we check for parallel
1443 // loading for them, wait if a defineClass is in progress
1444 // and return the initial requestor's results
1445 // This flag does not apply to the bootstrap classloader.
1446 // With AllowParallelDefine flag==false, call through to define_instance_class
1447 // which will throw LinkageError: duplicate class definition.
1448 // False is the requested default.
1449 // For better performance, the class loaders should synchronize
1450 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1451 // potentially waste time reading and parsing the bytestream.
1452 // Note: VM callers should ensure consistency of k/class_name,class_loader
1453 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1454
1455 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1456 Symbol* name_h = k->name(); // passed in class_name may be null
1457 ClassLoaderData* loader_data = class_loader_data(class_loader);
1458
1459 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1460 int d_index = dictionary()->hash_to_index(d_hash);
1461
1462 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1463 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1464 int p_index = placeholders()->hash_to_index(p_hash);
1465 PlaceholderEntry* probe;
1466
1467 {
1468 MutexLocker mu(SystemDictionary_lock, THREAD);
1469 // First check if class already defined
1470 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1471 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1472 if (check != NULL) {
1473 return(instanceKlassHandle(THREAD, check));
1474 }
1475 }
1476
1477 // Acquire define token for this class/classloader
1478 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1479 // Wait if another thread defining in parallel
1480 // All threads wait - even those that will throw duplicate class: otherwise
1481 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1482 // if other thread has not finished updating dictionary
1483 while (probe->definer() != NULL) {
1484 SystemDictionary_lock->wait();
1485 }
1486 // Only special cases allow parallel defines and can use other thread's results
1487 // Other cases fall through, and may run into duplicate defines
1488 // caught by finding an entry in the SystemDictionary
1489 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1490 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1491 SystemDictionary_lock->notify_all();
1492 #ifdef ASSERT
1493 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1494 assert(check != NULL, "definer missed recording success");
1495 #endif
1496 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1497 } else {
1498 // This thread will define the class (even if earlier thread tried and had an error)
1499 probe->set_definer(THREAD);
1500 }
1501 }
1502
1503 define_instance_class(k, THREAD);
1504
1505 Handle linkage_exception = Handle(); // null handle
1506
1507 // definer must notify any waiting threads
1508 {
1509 MutexLocker mu(SystemDictionary_lock, THREAD);
1510 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1511 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1512 if (probe != NULL) {
1513 if (HAS_PENDING_EXCEPTION) {
1514 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1515 CLEAR_PENDING_EXCEPTION;
1516 } else {
1517 probe->set_instance_klass(k());
1518 }
1519 probe->set_definer(NULL);
1520 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1521 SystemDictionary_lock->notify_all();
1522 }
1523 }
1524
1525 // Can't throw exception while holding lock due to rank ordering
1526 if (linkage_exception() != NULL) {
1527 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1528 }
1529
1530 return k;
1531 }
1532 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1533 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1534 if (class_loader.is_null()) {
1535 return Handle(THREAD, _system_loader_lock_obj);
1536 } else {
1537 return class_loader;
1538 }
1539 }
1540
1541 // This method is added to check how often we have to wait to grab loader
1542 // lock. The results are being recorded in the performance counters defined in
1543 // ClassLoader::_sync_systemLoaderLockContentionRate and
1544 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1545 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1546 if (!UsePerfData) {
1547 return;
1548 }
1549
1550 assert(!loader_lock.is_null(), "NULL lock object");
1551
1552 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1553 == ObjectSynchronizer::owner_other) {
1554 // contention will likely happen, so increment the corresponding
1555 // contention counter.
1556 if (loader_lock() == _system_loader_lock_obj) {
1557 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1558 } else {
1559 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1560 }
1561 }
1562 }
1563
1564 // ----------------------------------------------------------------------------
1565 // Lookup
1566
1567 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1568 Symbol* class_name,
1569 ClassLoaderData* loader_data) {
1570 assert_locked_or_safepoint(SystemDictionary_lock);
1571 assert (index == dictionary()->index_for(class_name, loader_data),
1572 "incorrect index?");
1573
1574 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1575 return k;
1576 }
1577
1578
1579 // Basic find on classes in the midst of being loaded
1580 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1581 ClassLoaderData* loader_data) {
1582 assert_locked_or_safepoint(SystemDictionary_lock);
1583 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1584 int p_index = placeholders()->hash_to_index(p_hash);
1585 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1586 }
1587
1588
1589 // Used for assertions and verification only
1590 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1591 #ifndef ASSERT
1592 guarantee(VerifyBeforeGC ||
1593 VerifyDuringGC ||
1594 VerifyBeforeExit ||
1595 VerifyDuringStartup ||
1596 VerifyAfterGC, "too expensive");
1597 #endif
1598 assert_locked_or_safepoint(SystemDictionary_lock);
1599
1600 // First look in the loaded class array
1601 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1602 int d_index = dictionary()->hash_to_index(d_hash);
1603 return find_class(d_index, d_hash, class_name, loader_data);
1604 }
1605
1606
1607 // Get the next class in the diictionary.
1608 Klass* SystemDictionary::try_get_next_class() {
1609 return dictionary()->try_get_next_class();
1610 }
1611
1612
1613 // ----------------------------------------------------------------------------
1614 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1615 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1616 // before a new class is used.
1617
1618 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1619 assert(k.not_null(), "just checking");
1620 assert_locked_or_safepoint(Compile_lock);
1621
1622 // Link into hierachy. Make sure the vtables are initialized before linking into
1623 k->append_to_sibling_list(); // add to superklass/sibling list
1624 k->process_interfaces(THREAD); // handle all "implements" declarations
1625 k->set_init_state(InstanceKlass::loaded);
1626 // Now flush all code that depended on old class hierarchy.
1627 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1628 // Also, first reinitialize vtable because it may have gotten out of synch
1629 // while the new class wasn't connected to the class hierarchy.
1630 Universe::flush_dependents_on(k);
1631 }
1632
1633 // ----------------------------------------------------------------------------
1634 // GC support
1635
1636 // Following roots during mark-sweep is separated in two phases.
1637 //
1638 // The first phase follows preloaded classes and all other system
1639 // classes, since these will never get unloaded anyway.
1640 //
1641 // The second phase removes (unloads) unreachable classes from the
1642 // system dictionary and follows the remaining classes' contents.
1643
1644 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1645 roots_oops_do(blk, NULL);
1646 }
1647
1648 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1649 // Follow all system classes and temporary placeholders in dictionary
1650 dictionary()->always_strong_classes_do(closure);
1651
1652 // Placeholders. These represent classes we're actively loading.
1653 placeholders()->classes_do(closure);
1654 }
1655
1656 // Calculate a "good" systemdictionary size based
1657 // on predicted or current loaded classes count
1658 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1659 int newsize = _old_default_sdsize;
1660 if ((classcount > 0) && !DumpSharedSpaces) {
1661 int desiredsize = classcount/_average_depth_goal;
1662 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1663 newsize = _primelist[++_sdgeneration]) {
1664 if (desiredsize <= newsize) {
1665 break;
1666 }
1667 }
1668 }
1669 return newsize;
1670 }
1671
1672 #ifdef ASSERT
1673 class VerifySDReachableAndLiveClosure : public OopClosure {
1674 private:
1675 BoolObjectClosure* _is_alive;
1676
1677 template <class T> void do_oop_work(T* p) {
1678 oop obj = oopDesc::load_decode_heap_oop(p);
1679 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1680 }
1681
1682 public:
1683 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1684
1685 virtual void do_oop(oop* p) { do_oop_work(p); }
1686 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1687 };
1688 #endif
1689
1690 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1691 // Note: anonymous classes are not in the SD.
1692 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1693 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1694 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1695 if (unloading_occurred) {
1696 dictionary()->do_unloading();
1697 constraints()->purge_loader_constraints();
1698 resolution_errors()->purge_resolution_errors();
1699 }
1700 // Oops referenced by the system dictionary may get unreachable independently
1701 // of the class loader (eg. cached protection domain oops). So we need to
1702 // explicitly unlink them here instead of in Dictionary::do_unloading.
1703 dictionary()->unlink(is_alive);
1704 #ifdef ASSERT
1705 VerifySDReachableAndLiveClosure cl(is_alive);
1706 dictionary()->oops_do(&cl);
1707 #endif
1708 return unloading_occurred;
1709 }
1710
1711 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1712 strong->do_oop(&_java_system_loader);
1713 strong->do_oop(&_system_loader_lock_obj);
1714 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1715
1716 // Adjust dictionary
1717 dictionary()->roots_oops_do(strong, weak);
1718
1719 // Visit extra methods
1720 invoke_method_table()->oops_do(strong);
1721 }
1722
1723 void SystemDictionary::oops_do(OopClosure* f) {
1724 f->do_oop(&_java_system_loader);
1725 f->do_oop(&_system_loader_lock_obj);
1726 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1727
1728 // Adjust dictionary
1729 dictionary()->oops_do(f);
1730
1731 // Visit extra methods
1732 invoke_method_table()->oops_do(f);
1733 }
1734
1735 // Extended Class redefinition support.
1736 // If one of these classes is replaced, we need to replace it in these places.
1737 // KlassClosure::do_klass should take the address of a class but we can
1738 // change that later.
1739 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1740 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1741 f->do_klass(_well_known_klasses[k]);
1742 }
1743
1744 {
1745 for (int i = 0; i < T_VOID+1; i++) {
1746 if (_box_klasses[i] != NULL) {
1747 assert(i >= T_BOOLEAN, "checking");
1748 f->do_klass(_box_klasses[i]);
1749 }
1750 }
1751 }
1752
1753 FilteredFieldsMap::classes_do(f);
1754 }
1755
1756 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1757 f->do_klass(_abstract_ownable_synchronizer_klass);
1758 }
1759
1760 // Just the classes from defining class loaders
1761 // Don't iterate over placeholders
1762 void SystemDictionary::classes_do(void f(Klass*)) {
1763 dictionary()->classes_do(f);
1764 }
1765
1766 // Added for initialize_itable_for_klass
1767 // Just the classes from defining class loaders
1768 // Don't iterate over placeholders
1769 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1770 dictionary()->classes_do(f, CHECK);
1771 }
1772
1773 // All classes, and their class loaders
1774 // Don't iterate over placeholders
1775 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1776 dictionary()->classes_do(f);
1777 }
1778
1779 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1780 placeholders()->entries_do(f);
1781 }
1782
1783 void SystemDictionary::methods_do(void f(Method*)) {
1784 dictionary()->methods_do(f);
1785 invoke_method_table()->methods_do(f);
1786 }
1787
1788 void SystemDictionary::remove_classes_in_error_state() {
1789 dictionary()->remove_classes_in_error_state();
1790 }
1791
1792 // ----------------------------------------------------------------------------
1793 // Lazily load klasses
1794
1795 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1796 // if multiple threads calling this function, only one thread will load
1797 // the class. The other threads will find the loaded version once the
1798 // class is loaded.
1799 Klass* aos = _abstract_ownable_synchronizer_klass;
1800 if (aos == NULL) {
1801 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1802 // Force a fence to prevent any read before the write completes
1803 OrderAccess::fence();
1804 _abstract_ownable_synchronizer_klass = k;
1805 }
1806 }
1807
1808 // ----------------------------------------------------------------------------
1809 // Initialization
1810
1811 void SystemDictionary::initialize(TRAPS) {
1812 // Allocate arrays
1813 assert(dictionary() == NULL,
1814 "SystemDictionary should only be initialized once");
1815 _sdgeneration = 0;
1816 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1817 _placeholders = new PlaceholderTable(_nof_buckets);
1818 _number_of_modifications = 0;
1819 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1820 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1821 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1822
1823 // Allocate private object used as system class loader lock
1824 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1825 // Initialize basic classes
1826 initialize_preloaded_classes(CHECK);
1827 }
1828
1829 // Compact table of directions on the initialization of klasses:
1830 static const short wk_init_info[] = {
1831 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1832 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1833 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1834 | (int)SystemDictionary::option ),
1835 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1836 #undef WK_KLASS_INIT_INFO
1837 0
1838 };
1839
1840 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1841 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1842 int info = wk_init_info[id - FIRST_WKID];
1843 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1844 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1845 Klass** klassp = &_well_known_klasses[id];
1846 bool must_load = (init_opt < SystemDictionary::Opt);
1847 if ((*klassp) == NULL) {
1848 if (must_load) {
1849 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1850 } else {
1851 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1852 }
1853 }
1854 return ((*klassp) != NULL);
1855 }
1856
1857 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1858 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1859 for (int id = (int)start_id; id < (int)limit_id; id++) {
1860 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1861 int info = wk_init_info[id - FIRST_WKID];
1862 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1863 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1864
1865 initialize_wk_klass((WKID)id, opt, CHECK);
1866 }
1867
1868 // move the starting value forward to the limit:
1869 start_id = limit_id;
1870 }
1871
1872 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1873 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1874 // Preload commonly used klasses
1875 WKID scan = FIRST_WKID;
1876 // first do Object, then String, Class
1877 if (UseSharedSpaces) {
1878 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1879 // Initialize the constant pool for the Object_class
1880 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1881 ik->constants()->restore_unshareable_info(CHECK);
1882 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1883 } else {
1884 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1885 }
1886
1887 // Calculate offsets for String and Class classes since they are loaded and
1888 // can be used after this point.
1889 java_lang_String::compute_offsets();
1890 java_lang_Class::compute_offsets();
1891
1892 // Fixup mirrors for classes loaded before java.lang.Class.
1893 // These calls iterate over the objects currently in the perm gen
1894 // so calling them at this point is matters (not before when there
1895 // are fewer objects and not later after there are more objects
1896 // in the perm gen.
1897 Universe::initialize_basic_type_mirrors(CHECK);
1898 Universe::fixup_mirrors(CHECK);
1899
1900 // do a bunch more:
1901 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1902
1903 // Preload ref klasses and set reference types
1904 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1905 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1906
1907 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1908 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1909 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1910 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1911 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1912
1913 // JSR 292 classes
1914 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1915 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1916 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1917 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1918 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1919
1920 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1921 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1922 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1923 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1924 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1925 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1926 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1927 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1928 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1929 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1930
1931 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1932 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1933 _has_loadClassInternal = (method != NULL);
1934 }
1935 { // Compute whether we should use checkPackageAccess or NOT
1936 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1937 _has_checkPackageAccess = (method != NULL);
1938 }
1939 }
1940
1941 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1942 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1943 BasicType SystemDictionary::box_klass_type(Klass* k) {
1944 assert(k != NULL, "");
1945 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1946 if (_box_klasses[i] == k)
1947 return (BasicType)i;
1948 }
1949 return T_OBJECT;
1950 }
1951
1952 // Constraints on class loaders. The details of the algorithm can be
1953 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1954 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1955 // that the system dictionary needs to maintain a set of contraints that
1956 // must be satisfied by all classes in the dictionary.
1957 // if defining is true, then LinkageError if already in systemDictionary
1958 // if initiating loader, then ok if InstanceKlass matches existing entry
1959
1960 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1961 instanceKlassHandle k,
1962 Handle class_loader, bool defining,
1963 TRAPS) {
1964 const char *linkage_error = NULL;
1965 {
1966 Symbol* name = k->name();
1967 ClassLoaderData *loader_data = class_loader_data(class_loader);
1968
1969 MutexLocker mu(SystemDictionary_lock, THREAD);
1970
1971 Klass* check = find_class(d_index, d_hash, name, loader_data);
1972 if (check != (Klass*)NULL) {
1973 // if different InstanceKlass - duplicate class definition,
1974 // else - ok, class loaded by a different thread in parallel,
1975 // we should only have found it if it was done loading and ok to use
1976 // system dictionary only holds instance classes, placeholders
1977 // also holds array classes
1978
1979 assert(check->oop_is_instance(), "noninstance in systemdictionary");
1980 if ((defining == true) || (k() != check)) {
1981 linkage_error = "loader (instance of %s): attempted duplicate class "
1982 "definition for name: \"%s\"";
1983 } else {
1984 return;
1985 }
1986 }
1987
1988 #ifdef ASSERT
1989 Symbol* ph_check = find_placeholder(name, loader_data);
1990 assert(ph_check == NULL || ph_check == name, "invalid symbol");
1991 #endif
1992
1993 if (linkage_error == NULL) {
1994 if (constraints()->check_or_update(k, class_loader, name) == false) {
1995 linkage_error = "loader constraint violation: loader (instance of %s)"
1996 " previously initiated loading for a different type with name \"%s\"";
1997 }
1998 }
1999 }
2000
2001 // Throw error now if needed (cannot throw while holding
2002 // SystemDictionary_lock because of rank ordering)
2003
2004 if (linkage_error) {
2005 ResourceMark rm(THREAD);
2006 const char* class_loader_name = loader_name(class_loader());
2007 char* type_name = k->name()->as_C_string();
2008 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2009 strlen(type_name);
2010 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2011 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2012 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2013 }
2014 }
2015
2016
2017 // Update system dictionary - done after check_constraint and add_to_hierachy
2018 // have been called.
2019 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2020 int p_index, unsigned int p_hash,
2021 instanceKlassHandle k,
2022 Handle class_loader,
2023 TRAPS) {
2024 // Compile_lock prevents systemDictionary updates during compilations
2025 assert_locked_or_safepoint(Compile_lock);
2026 Symbol* name = k->name();
2027 ClassLoaderData *loader_data = class_loader_data(class_loader);
2028
2029 {
2030 MutexLocker mu1(SystemDictionary_lock, THREAD);
2031
2032 // See whether biased locking is enabled and if so set it for this
2033 // klass.
2034 // Note that this must be done past the last potential blocking
2035 // point / safepoint. We enable biased locking lazily using a
2036 // VM_Operation to iterate the SystemDictionary and installing the
2037 // biasable mark word into each InstanceKlass's prototype header.
2038 // To avoid race conditions where we accidentally miss enabling the
2039 // optimization for one class in the process of being added to the
2040 // dictionary, we must not safepoint after the test of
2041 // BiasedLocking::enabled().
2042 if (UseBiasedLocking && BiasedLocking::enabled()) {
2043 // Set biased locking bit for all loaded classes; it will be
2044 // cleared if revocation occurs too often for this type
2045 // NOTE that we must only do this when the class is initally
2046 // defined, not each time it is referenced from a new class loader
2047 if (k->class_loader() == class_loader()) {
2048 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2049 }
2050 }
2051
2052 // Make a new system dictionary entry.
2053 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2054 if (sd_check == NULL) {
2055 dictionary()->add_klass(name, loader_data, k);
2056 notice_modification();
2057 }
2058 #ifdef ASSERT
2059 sd_check = find_class(d_index, d_hash, name, loader_data);
2060 assert (sd_check != NULL, "should have entry in system dictionary");
2061 // Note: there may be a placeholder entry: for circularity testing
2062 // or for parallel defines
2063 #endif
2064 SystemDictionary_lock->notify_all();
2065 }
2066 }
2067
2068
2069 // Try to find a class name using the loader constraints. The
2070 // loader constraints might know about a class that isn't fully loaded
2071 // yet and these will be ignored.
2072 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2073 Symbol* class_name, Handle class_loader, TRAPS) {
2074
2075 // First see if it has been loaded directly.
2076 // Force the protection domain to be null. (This removes protection checks.)
2077 Handle no_protection_domain;
2078 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2079 no_protection_domain, CHECK_NULL);
2080 if (klass != NULL)
2081 return klass;
2082
2083 // Now look to see if it has been loaded elsewhere, and is subject to
2084 // a loader constraint that would require this loader to return the
2085 // klass that is already loaded.
2086 if (FieldType::is_array(class_name)) {
2087 // For array classes, their Klass*s are not kept in the
2088 // constraint table. The element Klass*s are.
2089 FieldArrayInfo fd;
2090 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2091 if (t != T_OBJECT) {
2092 klass = Universe::typeArrayKlassObj(t);
2093 } else {
2094 MutexLocker mu(SystemDictionary_lock, THREAD);
2095 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2096 }
2097 // If element class already loaded, allocate array klass
2098 if (klass != NULL) {
2099 klass = klass->array_klass_or_null(fd.dimension());
2100 }
2101 } else {
2102 MutexLocker mu(SystemDictionary_lock, THREAD);
2103 // Non-array classes are easy: simply check the constraint table.
2104 klass = constraints()->find_constrained_klass(class_name, class_loader);
2105 }
2106
2107 return klass;
2108 }
2109
2110
2111 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2112 Handle class_loader1,
2113 Handle class_loader2,
2114 Thread* THREAD) {
2115 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2116 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2117
2118 Symbol* constraint_name = NULL;
2119 if (!FieldType::is_array(class_name)) {
2120 constraint_name = class_name;
2121 } else {
2122 // For array classes, their Klass*s are not kept in the
2123 // constraint table. The element classes are.
2124 FieldArrayInfo fd;
2125 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2126 // primitive types always pass
2127 if (t != T_OBJECT) {
2128 return true;
2129 } else {
2130 constraint_name = fd.object_key();
2131 }
2132 }
2133 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2134 int d_index1 = dictionary()->hash_to_index(d_hash1);
2135
2136 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2137 int d_index2 = dictionary()->hash_to_index(d_hash2);
2138 {
2139 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2140
2141 // Better never do a GC while we're holding these oops
2142 No_Safepoint_Verifier nosafepoint;
2143
2144 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2145 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2146 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2147 klass2, class_loader2);
2148 }
2149 }
2150
2151 // Add entry to resolution error table to record the error when the first
2152 // attempt to resolve a reference to a class has failed.
2153 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which,
2154 Symbol* error, Symbol* message) {
2155 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2156 int index = resolution_errors()->hash_to_index(hash);
2157 {
2158 MutexLocker ml(SystemDictionary_lock, Thread::current());
2159 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2160 }
2161 }
2162
2163 // Delete a resolution error for RedefineClasses for a constant pool is going away
2164 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2165 resolution_errors()->delete_entry(pool);
2166 }
2167
2168 // Lookup resolution error table. Returns error if found, otherwise NULL.
2169 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which,
2170 Symbol** message) {
2171 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2172 int index = resolution_errors()->hash_to_index(hash);
2173 {
2174 MutexLocker ml(SystemDictionary_lock, Thread::current());
2175 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2176 if (entry != NULL) {
2177 *message = entry->message();
2178 return entry->error();
2179 } else {
2180 return NULL;
2181 }
2182 }
2183 }
2184
2185
2186 // Signature constraints ensure that callers and callees agree about
2187 // the meaning of type names in their signatures. This routine is the
2188 // intake for constraints. It collects them from several places:
2189 //
2190 // * LinkResolver::resolve_method (if check_access is true) requires
2191 // that the resolving class (the caller) and the defining class of
2192 // the resolved method (the callee) agree on each type in the
2193 // method's signature.
2194 //
2195 // * LinkResolver::resolve_interface_method performs exactly the same
2196 // checks.
2197 //
2198 // * LinkResolver::resolve_field requires that the constant pool
2199 // attempting to link to a field agree with the field's defining
2200 // class about the type of the field signature.
2201 //
2202 // * klassVtable::initialize_vtable requires that, when a class
2203 // overrides a vtable entry allocated by a superclass, that the
2204 // overriding method (i.e., the callee) agree with the superclass
2205 // on each type in the method's signature.
2206 //
2207 // * klassItable::initialize_itable requires that, when a class fills
2208 // in its itables, for each non-abstract method installed in an
2209 // itable, the method (i.e., the callee) agree with the interface
2210 // on each type in the method's signature.
2211 //
2212 // All those methods have a boolean (check_access, checkconstraints)
2213 // which turns off the checks. This is used from specialized contexts
2214 // such as bootstrapping, dumping, and debugging.
2215 //
2216 // No direct constraint is placed between the class and its
2217 // supertypes. Constraints are only placed along linked relations
2218 // between callers and callees. When a method overrides or implements
2219 // an abstract method in a supertype (superclass or interface), the
2220 // constraints are placed as if the supertype were the caller to the
2221 // overriding method. (This works well, since callers to the
2222 // supertype have already established agreement between themselves and
2223 // the supertype.) As a result of all this, a class can disagree with
2224 // its supertype about the meaning of a type name, as long as that
2225 // class neither calls a relevant method of the supertype, nor is
2226 // called (perhaps via an override) from the supertype.
2227 //
2228 //
2229 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2230 //
2231 // Make sure all class components (including arrays) in the given
2232 // signature will be resolved to the same class in both loaders.
2233 // Returns the name of the type that failed a loader constraint check, or
2234 // NULL if no constraint failed. No exception except OOME is thrown.
2235 // Arrays are not added to the loader constraint table, their elements are.
2236 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2237 Handle loader1, Handle loader2,
2238 bool is_method, TRAPS) {
2239 // Nothing to do if loaders are the same.
2240 if (loader1() == loader2()) {
2241 return NULL;
2242 }
2243
2244 SignatureStream sig_strm(signature, is_method);
2245 while (!sig_strm.is_done()) {
2246 if (sig_strm.is_object()) {
2247 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2248 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2249 return sig;
2250 }
2251 }
2252 sig_strm.next();
2253 }
2254 return NULL;
2255 }
2256
2257
2258 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2259 Symbol* signature,
2260 TRAPS) {
2261 methodHandle empty;
2262 assert(MethodHandles::is_signature_polymorphic(iid) &&
2263 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2264 iid != vmIntrinsics::_invokeGeneric,
2265 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2266
2267 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2268 int index = invoke_method_table()->hash_to_index(hash);
2269 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2270 methodHandle m;
2271 if (spe == NULL || spe->method() == NULL) {
2272 spe = NULL;
2273 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2274 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2275 if (!Arguments::is_interpreter_only()) {
2276 // Generate a compiled form of the MH intrinsic.
2277 AdapterHandlerLibrary::create_native_wrapper(m);
2278 // Check if have the compiled code.
2279 if (!m->has_compiled_code()) {
2280 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2281 "out of space in CodeCache for method handle intrinsic", empty);
2282 }
2283 }
2284 // Now grab the lock. We might have to throw away the new method,
2285 // if a racing thread has managed to install one at the same time.
2286 {
2287 MutexLocker ml(SystemDictionary_lock, THREAD);
2288 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2289 if (spe == NULL)
2290 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2291 if (spe->method() == NULL)
2292 spe->set_method(m());
2293 }
2294 }
2295
2296 assert(spe != NULL && spe->method() != NULL, "");
2297 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2298 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2299 "MH intrinsic invariant");
2300 return spe->method();
2301 }
2302
2303 // Helper for unpacking the return value from linkMethod and linkCallSite.
2304 static methodHandle unpack_method_and_appendix(Handle mname,
2305 KlassHandle accessing_klass,
2306 objArrayHandle appendix_box,
2307 Handle* appendix_result,
2308 TRAPS) {
2309 methodHandle empty;
2310 if (mname.not_null()) {
2311 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2312 if (vmtarget != NULL && vmtarget->is_method()) {
2313 Method* m = (Method*)vmtarget;
2314 oop appendix = appendix_box->obj_at(0);
2315 if (TraceMethodHandles) {
2316 #ifndef PRODUCT
2317 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2318 m->print();
2319 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2320 tty->cr();
2321 #endif //PRODUCT
2322 }
2323 (*appendix_result) = Handle(THREAD, appendix);
2324 // the target is stored in the cpCache and if a reference to this
2325 // MethodName is dropped we need a way to make sure the
2326 // class_loader containing this method is kept alive.
2327 // FIXME: the appendix might also preserve this dependency.
2328 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2329 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2330 return methodHandle(THREAD, m);
2331 }
2332 }
2333 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2334 return empty;
2335 }
2336
2337 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2338 Symbol* signature,
2339 KlassHandle accessing_klass,
2340 Handle *appendix_result,
2341 Handle *method_type_result,
2342 TRAPS) {
2343 methodHandle empty;
2344 assert(!THREAD->is_Compiler_thread(), "");
2345 Handle method_type =
2346 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2347 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2348 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2349 }
2350
2351 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2352 int ref_kind = JVM_REF_invokeVirtual;
2353 Handle name_str = StringTable::intern(name, CHECK_(empty));
2354 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2355 assert(appendix_box->obj_at(0) == NULL, "");
2356
2357 // This should not happen. JDK code should take care of that.
2358 if (accessing_klass.is_null() || method_type.is_null()) {
2359 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2360 }
2361
2362 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2363 JavaCallArguments args;
2364 args.push_oop(accessing_klass()->java_mirror());
2365 args.push_int(ref_kind);
2366 args.push_oop(mh_klass()->java_mirror());
2367 args.push_oop(name_str());
2368 args.push_oop(method_type());
2369 args.push_oop(appendix_box());
2370 JavaValue result(T_OBJECT);
2371 JavaCalls::call_static(&result,
2372 SystemDictionary::MethodHandleNatives_klass(),
2373 vmSymbols::linkMethod_name(),
2374 vmSymbols::linkMethod_signature(),
2375 &args, CHECK_(empty));
2376 Handle mname(THREAD, (oop) result.get_jobject());
2377 (*method_type_result) = method_type;
2378 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2379 }
2380
2381
2382 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2383 // signature, as interpreted relative to the given class loader.
2384 // Because of class loader constraints, all method handle usage must be
2385 // consistent with this loader.
2386 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2387 KlassHandle accessing_klass,
2388 TRAPS) {
2389 Handle empty;
2390 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2391 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2392 int index = invoke_method_table()->hash_to_index(hash);
2393 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2394 if (spe != NULL && spe->method_type() != NULL) {
2395 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2396 return Handle(THREAD, spe->method_type());
2397 } else if (THREAD->is_Compiler_thread()) {
2398 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2399 return Handle(); // do not attempt from within compiler, unless it was cached
2400 }
2401
2402 Handle class_loader, protection_domain;
2403 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2404 int npts = ArgumentCount(signature).size();
2405 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2406 int arg = 0;
2407 Handle rt; // the return type from the signature
2408 ResourceMark rm(THREAD);
2409 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2410 oop mirror = NULL;
2411 if (is_on_bcp) {
2412 // Note: class_loader & protection_domain are both null at this point.
2413 mirror = ss.as_java_mirror(class_loader, protection_domain,
2414 SignatureStream::ReturnNull, CHECK_(empty));
2415 if (mirror == NULL) {
2416 // fall back from BCP to accessing_klass
2417 if (accessing_klass.not_null()) {
2418 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2419 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2420 }
2421 is_on_bcp = false;
2422 }
2423 }
2424 if (!is_on_bcp) {
2425 // Resolve, throwing a real error if it doesn't work.
2426 mirror = ss.as_java_mirror(class_loader, protection_domain,
2427 SignatureStream::NCDFError, CHECK_(empty));
2428 }
2429 if (ss.at_return_type())
2430 rt = Handle(THREAD, mirror);
2431 else
2432 pts->obj_at_put(arg++, mirror);
2433
2434 // Check accessibility.
2435 if (ss.is_object() && accessing_klass.not_null()) {
2436 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2437 mirror = NULL; // safety
2438 // Emulate ConstantPool::verify_constant_pool_resolve.
2439 if (sel_klass->oop_is_objArray())
2440 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2441 if (sel_klass->oop_is_instance()) {
2442 KlassHandle sel_kh(THREAD, sel_klass);
2443 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2444 }
2445 }
2446 }
2447 assert(arg == npts, "");
2448
2449 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2450 JavaCallArguments args(Handle(THREAD, rt()));
2451 args.push_oop(pts());
2452 JavaValue result(T_OBJECT);
2453 JavaCalls::call_static(&result,
2454 SystemDictionary::MethodHandleNatives_klass(),
2455 vmSymbols::findMethodHandleType_name(),
2456 vmSymbols::findMethodHandleType_signature(),
2457 &args, CHECK_(empty));
2458 Handle method_type(THREAD, (oop) result.get_jobject());
2459
2460 if (is_on_bcp) {
2461 // We can cache this MethodType inside the JVM.
2462 MutexLocker ml(SystemDictionary_lock, THREAD);
2463 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2464 if (spe == NULL)
2465 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2466 if (spe->method_type() == NULL) {
2467 spe->set_method_type(method_type());
2468 }
2469 }
2470
2471 // report back to the caller with the MethodType
2472 return method_type;
2473 }
2474
2475 // Ask Java code to find or construct a method handle constant.
2476 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2477 int ref_kind, //e.g., JVM_REF_invokeVirtual
2478 KlassHandle callee,
2479 Symbol* name_sym,
2480 Symbol* signature,
2481 TRAPS) {
2482 Handle empty;
2483 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2484 Handle type;
2485 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2486 type = find_method_handle_type(signature, caller, CHECK_(empty));
2487 } else if (caller.is_null()) {
2488 // This should not happen. JDK code should take care of that.
2489 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2490 } else {
2491 ResourceMark rm(THREAD);
2492 SignatureStream ss(signature, false);
2493 if (!ss.is_done()) {
2494 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2495 SignatureStream::NCDFError, CHECK_(empty));
2496 type = Handle(THREAD, mirror);
2497 ss.next();
2498 if (!ss.is_done()) type = Handle(); // error!
2499 }
2500 }
2501 if (type.is_null()) {
2502 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2503 }
2504
2505 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2506 JavaCallArguments args;
2507 args.push_oop(caller->java_mirror()); // the referring class
2508 args.push_int(ref_kind);
2509 args.push_oop(callee->java_mirror()); // the target class
2510 args.push_oop(name());
2511 args.push_oop(type());
2512 JavaValue result(T_OBJECT);
2513 JavaCalls::call_static(&result,
2514 SystemDictionary::MethodHandleNatives_klass(),
2515 vmSymbols::linkMethodHandleConstant_name(),
2516 vmSymbols::linkMethodHandleConstant_signature(),
2517 &args, CHECK_(empty));
2518 return Handle(THREAD, (oop) result.get_jobject());
2519 }
2520
2521 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2522 // name and signature, as interpreted relative to the given class loader.
2523 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2524 Handle bootstrap_specifier,
2525 Symbol* name,
2526 Symbol* type,
2527 Handle *appendix_result,
2528 Handle *method_type_result,
2529 TRAPS) {
2530 methodHandle empty;
2531 Handle bsm, info;
2532 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2533 bsm = bootstrap_specifier;
2534 } else {
2535 assert(bootstrap_specifier->is_objArray(), "");
2536 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2537 int len = args->length();
2538 assert(len >= 1, "");
2539 bsm = Handle(THREAD, args->obj_at(0));
2540 if (len > 1) {
2541 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2542 for (int i = 1; i < len; i++)
2543 args1->obj_at_put(i-1, args->obj_at(i));
2544 info = Handle(THREAD, args1);
2545 }
2546 }
2547 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2548 "caller must supply a valid BSM");
2549
2550 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2551 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2552
2553 // This should not happen. JDK code should take care of that.
2554 if (caller.is_null() || method_type.is_null()) {
2555 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2556 }
2557
2558 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2559 assert(appendix_box->obj_at(0) == NULL, "");
2560
2561 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2562 JavaCallArguments args;
2563 args.push_oop(caller->java_mirror());
2564 args.push_oop(bsm());
2565 args.push_oop(method_name());
2566 args.push_oop(method_type());
2567 args.push_oop(info());
2568 args.push_oop(appendix_box);
2569 JavaValue result(T_OBJECT);
2570 JavaCalls::call_static(&result,
2571 SystemDictionary::MethodHandleNatives_klass(),
2572 vmSymbols::linkCallSite_name(),
2573 vmSymbols::linkCallSite_signature(),
2574 &args, CHECK_(empty));
2575 Handle mname(THREAD, (oop) result.get_jobject());
2576 (*method_type_result) = method_type;
2577 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2578 }
2579
2580 // Since the identity hash code for symbols changes when the symbols are
2581 // moved from the regular perm gen (hash in the mark word) to the shared
2582 // spaces (hash is the address), the classes loaded into the dictionary
2583 // may be in the wrong buckets.
2584
2585 void SystemDictionary::reorder_dictionary() {
2586 dictionary()->reorder_dictionary();
2587 }
2588
2589
2590 void SystemDictionary::copy_buckets(char** top, char* end) {
2591 dictionary()->copy_buckets(top, end);
2592 }
2593
2594
2595 void SystemDictionary::copy_table(char** top, char* end) {
2596 dictionary()->copy_table(top, end);
2597 }
2598
2599
2600 void SystemDictionary::reverse() {
2601 dictionary()->reverse();
2602 }
2603
2604 int SystemDictionary::number_of_classes() {
2605 return dictionary()->number_of_entries();
2606 }
2607
2608
2609 // ----------------------------------------------------------------------------
2610 void SystemDictionary::print_shared(bool details) {
2611 shared_dictionary()->print(details);
2612 }
2613
2614 void SystemDictionary::print(bool details) {
2615 dictionary()->print(details);
2616
2617 // Placeholders
2618 GCMutexLocker mu(SystemDictionary_lock);
2619 placeholders()->print();
2620
2621 // loader constraints - print under SD_lock
2622 constraints()->print();
2623 }
2624
2625
2626 void SystemDictionary::verify() {
2627 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2628 guarantee(constraints() != NULL,
2629 "Verify of loader constraints failed");
2630 guarantee(dictionary()->number_of_entries() >= 0 &&
2631 placeholders()->number_of_entries() >= 0,
2632 "Verify of system dictionary failed");
2633
2634 // Verify dictionary
2635 dictionary()->verify();
2636
2637 GCMutexLocker mu(SystemDictionary_lock);
2638 placeholders()->verify();
2639
2640 // Verify constraint table
2641 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2642 constraints()->verify(dictionary(), placeholders());
2643 }
2644
2645 // utility function for class load event
2646 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2647 instanceKlassHandle k,
2648 Handle initiating_loader) {
2649 #if INCLUDE_TRACE
2650 EventClassLoad event(UNTIMED);
2651 if (event.should_commit()) {
2652 event.set_starttime(start_time);
2653 event.set_loadedClass(k());
2654 oop defining_class_loader = k->class_loader();
2655 event.set_definingClassLoader(defining_class_loader != NULL ?
2656 defining_class_loader->klass() : (Klass*)NULL);
2657 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2658 event.set_initiatingClassLoader(class_loader != NULL ?
2659 class_loader->klass() : (Klass*)NULL);
2660 event.commit();
2661 }
2662 #endif // INCLUDE_TRACE
2663 }
2664
2665 #ifndef PRODUCT
2666
2667 // statistics code
2668 class ClassStatistics: AllStatic {
2669 private:
2670 static int nclasses; // number of classes
2671 static int nmethods; // number of methods
2672 static int nmethoddata; // number of methodData
2673 static int class_size; // size of class objects in words
2674 static int method_size; // size of method objects in words
2675 static int debug_size; // size of debug info in methods
2676 static int methoddata_size; // size of methodData objects in words
2677
2678 static void do_class(Klass* k) {
2679 nclasses++;
2680 class_size += k->size();
2681 if (k->oop_is_instance()) {
2682 InstanceKlass* ik = (InstanceKlass*)k;
2683 class_size += ik->methods()->size();
2684 class_size += ik->constants()->size();
2685 class_size += ik->local_interfaces()->size();
2686 class_size += ik->transitive_interfaces()->size();
2687 // We do not have to count implementors, since we only store one!
2688 // SSS: How should these be accounted now that they have moved?
2689 // class_size += ik->fields()->length();
2690 }
2691 }
2692
2693 static void do_method(Method* m) {
2694 nmethods++;
2695 method_size += m->size();
2696 // class loader uses same objArray for empty vectors, so don't count these
2697 if (m->has_stackmap_table()) {
2698 method_size += m->stackmap_data()->size();
2699 }
2700
2701 MethodData* mdo = m->method_data();
2702 if (mdo != NULL) {
2703 nmethoddata++;
2704 methoddata_size += mdo->size();
2705 }
2706 }
2707
2708 public:
2709 static void print() {
2710 SystemDictionary::classes_do(do_class);
2711 SystemDictionary::methods_do(do_method);
2712 tty->print_cr("Class statistics:");
2713 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2714 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2715 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2716 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2717 }
2718 };
2719
2720
2721 int ClassStatistics::nclasses = 0;
2722 int ClassStatistics::nmethods = 0;
2723 int ClassStatistics::nmethoddata = 0;
2724 int ClassStatistics::class_size = 0;
2725 int ClassStatistics::method_size = 0;
2726 int ClassStatistics::debug_size = 0;
2727 int ClassStatistics::methoddata_size = 0;
2728
2729 void SystemDictionary::print_class_statistics() {
2730 ResourceMark rm;
2731 ClassStatistics::print();
2732 }
2733
2734
2735 class MethodStatistics: AllStatic {
2736 public:
2737 enum {
2738 max_parameter_size = 10
2739 };
2740 private:
2741
2742 static int _number_of_methods;
2743 static int _number_of_final_methods;
2744 static int _number_of_static_methods;
2745 static int _number_of_native_methods;
2746 static int _number_of_synchronized_methods;
2747 static int _number_of_profiled_methods;
2748 static int _number_of_bytecodes;
2749 static int _parameter_size_profile[max_parameter_size];
2750 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2751
2752 static void initialize() {
2753 _number_of_methods = 0;
2754 _number_of_final_methods = 0;
2755 _number_of_static_methods = 0;
2756 _number_of_native_methods = 0;
2757 _number_of_synchronized_methods = 0;
2758 _number_of_profiled_methods = 0;
2759 _number_of_bytecodes = 0;
2760 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2761 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2762 };
2763
2764 static void do_method(Method* m) {
2765 _number_of_methods++;
2766 // collect flag info
2767 if (m->is_final() ) _number_of_final_methods++;
2768 if (m->is_static() ) _number_of_static_methods++;
2769 if (m->is_native() ) _number_of_native_methods++;
2770 if (m->is_synchronized()) _number_of_synchronized_methods++;
2771 if (m->method_data() != NULL) _number_of_profiled_methods++;
2772 // collect parameter size info (add one for receiver, if any)
2773 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2774 // collect bytecodes info
2775 {
2776 Thread *thread = Thread::current();
2777 HandleMark hm(thread);
2778 BytecodeStream s(methodHandle(thread, m));
2779 Bytecodes::Code c;
2780 while ((c = s.next()) >= 0) {
2781 _number_of_bytecodes++;
2782 _bytecodes_profile[c]++;
2783 }
2784 }
2785 }
2786
2787 public:
2788 static void print() {
2789 initialize();
2790 SystemDictionary::methods_do(do_method);
2791 // generate output
2792 tty->cr();
2793 tty->print_cr("Method statistics (static):");
2794 // flag distribution
2795 tty->cr();
2796 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2797 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2798 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2799 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2800 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2801 // parameter size profile
2802 tty->cr();
2803 { int tot = 0;
2804 int avg = 0;
2805 for (int i = 0; i < max_parameter_size; i++) {
2806 int n = _parameter_size_profile[i];
2807 tot += n;
2808 avg += n*i;
2809 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2810 }
2811 assert(tot == _number_of_methods, "should be the same");
2812 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2813 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2814 }
2815 // bytecodes profile
2816 tty->cr();
2817 { int tot = 0;
2818 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2819 if (Bytecodes::is_defined(i)) {
2820 Bytecodes::Code c = Bytecodes::cast(i);
2821 int n = _bytecodes_profile[c];
2822 tot += n;
2823 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2824 }
2825 }
2826 assert(tot == _number_of_bytecodes, "should be the same");
2827 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2828 }
2829 tty->cr();
2830 }
2831 };
2832
2833 int MethodStatistics::_number_of_methods;
2834 int MethodStatistics::_number_of_final_methods;
2835 int MethodStatistics::_number_of_static_methods;
2836 int MethodStatistics::_number_of_native_methods;
2837 int MethodStatistics::_number_of_synchronized_methods;
2838 int MethodStatistics::_number_of_profiled_methods;
2839 int MethodStatistics::_number_of_bytecodes;
2840 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2841 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2842
2843
2844 void SystemDictionary::print_method_statistics() {
2845 MethodStatistics::print();
2846 }
2847
2848 #endif // PRODUCT