1 /*
2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "interpreter/bytecodeStream.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/gcLocker.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/methodData.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "oops/typeArrayKlass.hpp"
47 #include "prims/jvmtiEnvBase.hpp"
48 #include "prims/methodHandles.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fieldType.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/signature.hpp"
56 #include "services/classLoadingService.hpp"
57 #include "services/threadService.hpp"
58
59
60 Dictionary* SystemDictionary::_dictionary = NULL;
61 PlaceholderTable* SystemDictionary::_placeholders = NULL;
62 Dictionary* SystemDictionary::_shared_dictionary = NULL;
63 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
64 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
65 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
66
67
68 int SystemDictionary::_number_of_modifications = 0;
69 int SystemDictionary::_sdgeneration = 0;
70 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
71 20201,40423,99991};
72
73 oop SystemDictionary::_system_loader_lock_obj = NULL;
74
75 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
76 = { NULL /*, NULL...*/ };
77
78 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
79
80 oop SystemDictionary::_java_system_loader = NULL;
81
82 bool SystemDictionary::_has_loadClassInternal = false;
83 bool SystemDictionary::_has_checkPackageAccess = false;
84
85 // lazily initialized klass variables
86 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
87
88
89 // ----------------------------------------------------------------------------
90 // Java-level SystemLoader
91
92 oop SystemDictionary::java_system_loader() {
93 return _java_system_loader;
94 }
95
96 void SystemDictionary::compute_java_system_loader(TRAPS) {
97 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
98 JavaValue result(T_OBJECT);
99 JavaCalls::call_static(&result,
100 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
101 vmSymbols::getSystemClassLoader_name(),
102 vmSymbols::void_classloader_signature(),
103 CHECK);
104
105 _java_system_loader = (oop)result.get_jobject();
106 }
107
108
109 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
110 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
111 return ClassLoaderDataGraph::find_or_create(class_loader);
112 }
113
114 // ----------------------------------------------------------------------------
115 // debugging
116
117 #ifdef ASSERT
118
119 // return true if class_name contains no '.' (internal format is '/')
120 bool SystemDictionary::is_internal_format(Symbol* class_name) {
121 if (class_name != NULL) {
122 ResourceMark rm;
123 char* name = class_name->as_C_string();
124 return strchr(name, '.') == NULL;
125 } else {
126 return true;
127 }
128 }
129
130 #endif
131
132 // ----------------------------------------------------------------------------
133 // Parallel class loading check
134
135 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
136 if (UnsyncloadClass || class_loader.is_null()) return true;
137 if (AlwaysLockClassLoader) return false;
138 return java_lang_ClassLoader::parallelCapable(class_loader());
139 }
140 // ----------------------------------------------------------------------------
141 // ParallelDefineClass flag does not apply to bootclass loader
142 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
143 if (class_loader.is_null()) return false;
144 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
145 return true;
146 }
147 return false;
148 }
149 // ----------------------------------------------------------------------------
150 // Resolving of classes
151
152 // Forwards to resolve_or_null
153
154 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
155 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
156 if (HAS_PENDING_EXCEPTION || klass == NULL) {
157 KlassHandle k_h(THREAD, klass);
158 // can return a null klass
159 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
160 }
161 return klass;
162 }
163
164 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
165 if (HAS_PENDING_EXCEPTION) {
166 // If we have a pending exception we forward it to the caller, unless throw_error is true,
167 // in which case we have to check whether the pending exception is a ClassNotFoundException,
168 // and if so convert it to a NoClassDefFoundError
169 // And chain the original ClassNotFoundException
170 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
171 ResourceMark rm(THREAD);
172 assert(klass_h() == NULL, "Should not have result with exception pending");
173 Handle e(THREAD, PENDING_EXCEPTION);
174 CLEAR_PENDING_EXCEPTION;
175 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
176 } else {
177 return NULL;
178 }
179 }
180 // Class not found, throw appropriate error or exception depending on value of throw_error
181 if (klass_h() == NULL) {
182 ResourceMark rm(THREAD);
183 if (throw_error) {
184 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
185 } else {
186 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
187 }
188 }
189 return (Klass*)klass_h();
190 }
191
192
193 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
194 bool throw_error, TRAPS)
195 {
196 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
197 }
198
199
200 // Forwards to resolve_instance_class_or_null
201
202 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
203 assert(!THREAD->is_Compiler_thread(),
204 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
205 class_name->as_C_string(),
206 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
207 if (FieldType::is_array(class_name)) {
208 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
209 } else if (FieldType::is_obj(class_name)) {
210 ResourceMark rm(THREAD);
211 // Ignore wrapping L and ;.
212 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
213 class_name->utf8_length() - 2, CHECK_NULL);
214 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
215 } else {
216 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
217 }
218 }
219
220 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
221 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
222 }
223
224 // Forwards to resolve_instance_class_or_null
225
226 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
227 Handle class_loader,
228 Handle protection_domain,
229 TRAPS) {
230 assert(FieldType::is_array(class_name), "must be array");
231 Klass* k = NULL;
232 FieldArrayInfo fd;
233 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
234 // of this call
235 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
236 if (t == T_OBJECT) {
237 // naked oop "k" is OK here -- we assign back into it
238 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
239 class_loader,
240 protection_domain,
241 CHECK_NULL);
242 if (k != NULL) {
243 k = Klass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
244 }
245 } else {
246 k = Universe::typeArrayKlassObj(t);
247 k = typeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
248 }
249 return k;
250 }
251
252
253 // Must be called for any super-class or super-interface resolution
254 // during class definition to allow class circularity checking
255 // super-interface callers:
256 // parse_interfaces - for defineClass & jvmtiRedefineClasses
257 // super-class callers:
258 // ClassFileParser - for defineClass & jvmtiRedefineClasses
259 // load_shared_class - while loading a class from shared archive
260 // resolve_instance_class_or_null:
261 // via: handle_parallel_super_load
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
289 Symbol* class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
294
295 // Try to get one of the well-known klasses.
296 // They are trusted, and do not participate in circularities.
297 if (LinkWellKnownClasses) {
298 Klass* k = find_well_known_klass(class_name);
299 if (k != NULL) {
300 return k;
301 }
302 }
303
304 // Double-check, if child class is already loaded, just return super-class,interface
305 // Don't add a placedholder if already loaded, i.e. already in system dictionary
306 // Make sure there's a placeholder for the *child* before resolving.
307 // Used as a claim that this thread is currently loading superclass/classloader
308 // Used here for ClassCircularity checks and also for heap verification
309 // (every InstanceKlass in the heap needs to be in the system dictionary
310 // or have a placeholder).
311 // Must check ClassCircularity before checking if super class is already loaded
312 //
313 // We might not already have a placeholder if this child_name was
314 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
315 // the name of the class might not be known until the stream is actually
316 // parsed.
317 // Bugs 4643874, 4715493
318 // compute_hash can have a safepoint
319
320 ClassLoaderData* loader_data = class_loader_data(class_loader);
321 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
322 int d_index = dictionary()->hash_to_index(d_hash);
323 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
324 int p_index = placeholders()->hash_to_index(p_hash);
325 // can't throw error holding a lock
326 bool child_already_loaded = false;
327 bool throw_circularity_error = false;
328 {
329 MutexLocker mu(SystemDictionary_lock, THREAD);
330 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
331 Klass* quicksuperk;
332 // to support // loading: if child done loading, just return superclass
333 // if class_name, & class_loader don't match:
334 // if initial define, SD update will give LinkageError
335 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
336 // so we don't throw an exception here.
337 // see: nsk redefclass014 & java.lang.instrument Instrument032
338 if ((childk != NULL ) && (is_superclass) &&
339 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
340
341 ((Klass::cast(quicksuperk)->name() == class_name) &&
342 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
343 return quicksuperk;
344 } else {
345 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
346 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
347 throw_circularity_error = true;
348 }
349 }
350 if (!throw_circularity_error) {
351 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
352 }
353 }
354 if (throw_circularity_error) {
355 ResourceMark rm(THREAD);
356 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
357 }
358
359 // java.lang.Object should have been found above
360 assert(class_name != NULL, "null super class for resolving");
361 // Resolve the super class or interface, check results on return
362 Klass* superk = NULL;
363 superk = SystemDictionary::resolve_or_null(class_name,
364 class_loader,
365 protection_domain,
366 THREAD);
367
368 KlassHandle superk_h(THREAD, superk);
369
370 // Note: clean up of placeholders currently in callers of
371 // resolve_super_or_fail - either at update_dictionary time
372 // or on error
373 {
374 MutexLocker mu(SystemDictionary_lock, THREAD);
375 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
376 if (probe != NULL) {
377 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
378 }
379 }
380 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
381 // can null superk
382 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
383 }
384
385 return superk_h();
386 }
387
388 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
389 Handle class_loader,
390 Handle protection_domain,
391 TRAPS) {
392 if(!has_checkPackageAccess()) return;
393
394 // Now we have to call back to java to check if the initating class has access
395 JavaValue result(T_VOID);
396 if (TraceProtectionDomainVerification) {
397 // Print out trace information
398 tty->print_cr("Checking package access");
399 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
400 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
401 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
402 }
403
404 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
405 JavaCalls::call_special(&result,
406 class_loader,
407 system_loader,
408 vmSymbols::checkPackageAccess_name(),
409 vmSymbols::class_protectiondomain_signature(),
410 Handle(THREAD, klass->java_mirror()),
411 protection_domain,
412 THREAD);
413
414 if (TraceProtectionDomainVerification) {
415 if (HAS_PENDING_EXCEPTION) {
416 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
417 } else {
418 tty->print_cr(" -> granted");
419 }
420 tty->cr();
421 }
422
423 if (HAS_PENDING_EXCEPTION) return;
424
425 // If no exception has been thrown, we have validated the protection domain
426 // Insert the protection domain of the initiating class into the set.
427 {
428 // We recalculate the entry here -- we've called out to java since
429 // the last time it was calculated.
430 ClassLoaderData* loader_data = class_loader_data(class_loader);
431
432 Symbol* kn = klass->name();
433 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
434 int d_index = dictionary()->hash_to_index(d_hash);
435
436 MutexLocker mu(SystemDictionary_lock, THREAD);
437 {
438 // Note that we have an entry, and entries can be deleted only during GC,
439 // so we cannot allow GC to occur while we're holding this entry.
440
441 // We're using a No_Safepoint_Verifier to catch any place where we
442 // might potentially do a GC at all.
443 // SystemDictionary::do_unloading() asserts that classes are only
444 // unloaded at a safepoint.
445 No_Safepoint_Verifier nosafepoint;
446 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
447 protection_domain, THREAD);
448 }
449 }
450 }
451
452 // We only get here if this thread finds that another thread
453 // has already claimed the placeholder token for the current operation,
454 // but that other thread either never owned or gave up the
455 // object lock
456 // Waits on SystemDictionary_lock to indicate placeholder table updated
457 // On return, caller must recheck placeholder table state
458 //
459 // We only get here if
460 // 1) custom classLoader, i.e. not bootstrap classloader
461 // 2) UnsyncloadClass not set
462 // 3) custom classLoader has broken the class loader objectLock
463 // so another thread got here in parallel
464 //
465 // lockObject must be held.
466 // Complicated dance due to lock ordering:
467 // Must first release the classloader object lock to
468 // allow initial definer to complete the class definition
469 // and to avoid deadlock
470 // Reclaim classloader lock object with same original recursion count
471 // Must release SystemDictionary_lock after notify, since
472 // class loader lock must be claimed before SystemDictionary_lock
473 // to prevent deadlocks
474 //
475 // The notify allows applications that did an untimed wait() on
476 // the classloader object lock to not hang.
477 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
478 assert_lock_strong(SystemDictionary_lock);
479
480 bool calledholdinglock
481 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
482 assert(calledholdinglock,"must hold lock for notify");
483 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
484 ObjectSynchronizer::notifyall(lockObject, THREAD);
485 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
486 SystemDictionary_lock->wait();
487 SystemDictionary_lock->unlock();
488 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
489 SystemDictionary_lock->lock();
490 }
491
492 // If the class in is in the placeholder table, class loading is in progress
493 // For cases where the application changes threads to load classes, it
494 // is critical to ClassCircularity detection that we try loading
495 // the superclass on the same thread internally, so we do parallel
496 // super class loading here.
497 // This also is critical in cases where the original thread gets stalled
498 // even in non-circularity situations.
499 // Note: only one thread can define the class, but multiple can resolve
500 // Note: must call resolve_super_or_fail even if null super -
501 // to force placeholder entry creation for this class for circularity detection
502 // Caller must check for pending exception
503 // Returns non-null Klass* if other thread has completed load
504 // and we are done,
505 // If return null Klass* and no pending exception, the caller must load the class
506 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
507 Symbol* name, Symbol* superclassname, Handle class_loader,
508 Handle protection_domain, Handle lockObject, TRAPS) {
509
510 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
511 ClassLoaderData* loader_data = class_loader_data(class_loader);
512 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
513 int d_index = dictionary()->hash_to_index(d_hash);
514 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
515 int p_index = placeholders()->hash_to_index(p_hash);
516
517 // superk is not used, resolve_super called for circularity check only
518 // This code is reached in two situations. One if this thread
519 // is loading the same class twice (e.g. ClassCircularity, or
520 // java.lang.instrument).
521 // The second is if another thread started the resolve_super first
522 // and has not yet finished.
523 // In both cases the original caller will clean up the placeholder
524 // entry on error.
525 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
526 superclassname,
527 class_loader,
528 protection_domain,
529 true,
530 CHECK_(nh));
531 // We don't redefine the class, so we just need to clean up if there
532 // was not an error (don't want to modify any system dictionary
533 // data structures).
534 {
535 MutexLocker mu(SystemDictionary_lock, THREAD);
536 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
537 SystemDictionary_lock->notify_all();
538 }
539
540 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
541 // Serial class loaders and bootstrap classloader do wait for superclass loads
542 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
543 MutexLocker mu(SystemDictionary_lock, THREAD);
544 // Check if classloading completed while we were loading superclass or waiting
545 Klass* check = find_class(d_index, d_hash, name, loader_data);
546 if (check != NULL) {
547 // Klass is already loaded, so just return it
548 return(instanceKlassHandle(THREAD, check));
549 } else {
550 return nh;
551 }
552 }
553
554 // must loop to both handle other placeholder updates
555 // and spurious notifications
556 bool super_load_in_progress = true;
557 PlaceholderEntry* placeholder;
558 while (super_load_in_progress) {
559 MutexLocker mu(SystemDictionary_lock, THREAD);
560 // Check if classloading completed while we were loading superclass or waiting
561 Klass* check = find_class(d_index, d_hash, name, loader_data);
562 if (check != NULL) {
563 // Klass is already loaded, so just return it
564 return(instanceKlassHandle(THREAD, check));
565 } else {
566 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
567 if (placeholder && placeholder->super_load_in_progress() ){
568 // Before UnsyncloadClass:
569 // We only get here if the application has released the
570 // classloader lock when another thread was in the middle of loading a
571 // superclass/superinterface for this class, and now
572 // this thread is also trying to load this class.
573 // To minimize surprises, the first thread that started to
574 // load a class should be the one to complete the loading
575 // with the classfile it initially expected.
576 // This logic has the current thread wait once it has done
577 // all the superclass/superinterface loading it can, until
578 // the original thread completes the class loading or fails
579 // If it completes we will use the resulting InstanceKlass
580 // which we will find below in the systemDictionary.
581 // We also get here for parallel bootstrap classloader
582 if (class_loader.is_null()) {
583 SystemDictionary_lock->wait();
584 } else {
585 double_lock_wait(lockObject, THREAD);
586 }
587 } else {
588 // If not in SD and not in PH, other thread's load must have failed
589 super_load_in_progress = false;
590 }
591 }
592 }
593 return (nh);
594 }
595
596
597 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
598 assert(name != NULL && !FieldType::is_array(name) &&
599 !FieldType::is_obj(name), "invalid class name");
600
601 // UseNewReflection
602 // Fix for 4474172; see evaluation for more details
603 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
604 ClassLoaderData *loader_data = register_loader(class_loader);
605
606 // Do lookup to see if class already exist and the protection domain
607 // has the right access
608 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
609 int d_index = dictionary()->hash_to_index(d_hash);
610 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
611 protection_domain, THREAD);
612 if (probe != NULL) return probe;
613
614
615 // Non-bootstrap class loaders will call out to class loader and
616 // define via jvm/jni_DefineClass which will acquire the
617 // class loader object lock to protect against multiple threads
618 // defining the class in parallel by accident.
619 // This lock must be acquired here so the waiter will find
620 // any successful result in the SystemDictionary and not attempt
621 // the define
622 // ParallelCapable Classloaders and the bootstrap classloader,
623 // or all classloaders with UnsyncloadClass do not acquire lock here
624 bool DoObjectLock = true;
625 if (is_parallelCapable(class_loader)) {
626 DoObjectLock = false;
627 }
628
629 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
630 int p_index = placeholders()->hash_to_index(p_hash);
631
632 // Class is not in SystemDictionary so we have to do loading.
633 // Make sure we are synchronized on the class loader before we proceed
634 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
635 check_loader_lock_contention(lockObject, THREAD);
636 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
637
638 // Check again (after locking) if class already exist in SystemDictionary
639 bool class_has_been_loaded = false;
640 bool super_load_in_progress = false;
641 bool havesupername = false;
642 instanceKlassHandle k;
643 PlaceholderEntry* placeholder;
644 Symbol* superclassname = NULL;
645
646 {
647 MutexLocker mu(SystemDictionary_lock, THREAD);
648 Klass* check = find_class(d_index, d_hash, name, loader_data);
649 if (check != NULL) {
650 // Klass is already loaded, so just return it
651 class_has_been_loaded = true;
652 k = instanceKlassHandle(THREAD, check);
653 } else {
654 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
655 if (placeholder && placeholder->super_load_in_progress()) {
656 super_load_in_progress = true;
657 if (placeholder->havesupername() == true) {
658 superclassname = placeholder->supername();
659 havesupername = true;
660 }
661 }
662 }
663 }
664
665 // If the class in is in the placeholder table, class loading is in progress
666 if (super_load_in_progress && havesupername==true) {
667 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
668 class_loader, protection_domain, lockObject, THREAD);
669 if (HAS_PENDING_EXCEPTION) {
670 return NULL;
671 }
672 if (!k.is_null()) {
673 class_has_been_loaded = true;
674 }
675 }
676
677 if (!class_has_been_loaded) {
678
679 // add placeholder entry to record loading instance class
680 // Five cases:
681 // All cases need to prevent modifying bootclasssearchpath
682 // in parallel with a classload of same classname
683 // Redefineclasses uses existence of the placeholder for the duration
684 // of the class load to prevent concurrent redefinition of not completely
685 // defined classes.
686 // case 1. traditional classloaders that rely on the classloader object lock
687 // - no other need for LOAD_INSTANCE
688 // case 2. traditional classloaders that break the classloader object lock
689 // as a deadlock workaround. Detection of this case requires that
690 // this check is done while holding the classloader object lock,
691 // and that lock is still held when calling classloader's loadClass.
692 // For these classloaders, we ensure that the first requestor
693 // completes the load and other requestors wait for completion.
694 // case 3. UnsyncloadClass - don't use objectLocker
695 // With this flag, we allow parallel classloading of a
696 // class/classloader pair
697 // case4. Bootstrap classloader - don't own objectLocker
698 // This classloader supports parallelism at the classloader level,
699 // but only allows a single load of a class/classloader pair.
700 // No performance benefit and no deadlock issues.
701 // case 5. parallelCapable user level classloaders - without objectLocker
702 // Allow parallel classloading of a class/classloader pair
703 bool throw_circularity_error = false;
704 {
705 MutexLocker mu(SystemDictionary_lock, THREAD);
706 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
707 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
708 if (oldprobe) {
709 // only need check_seen_thread once, not on each loop
710 // 6341374 java/lang/Instrument with -Xcomp
711 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
712 throw_circularity_error = true;
713 } else {
714 // case 1: traditional: should never see load_in_progress.
715 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
716
717 // case 4: bootstrap classloader: prevent futile classloading,
718 // wait on first requestor
719 if (class_loader.is_null()) {
720 SystemDictionary_lock->wait();
721 } else {
722 // case 2: traditional with broken classloader lock. wait on first
723 // requestor.
724 double_lock_wait(lockObject, THREAD);
725 }
726 // Check if classloading completed while we were waiting
727 Klass* check = find_class(d_index, d_hash, name, loader_data);
728 if (check != NULL) {
729 // Klass is already loaded, so just return it
730 k = instanceKlassHandle(THREAD, check);
731 class_has_been_loaded = true;
732 }
733 // check if other thread failed to load and cleaned up
734 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
735 }
736 }
737 }
738 }
739 // All cases: add LOAD_INSTANCE
740 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
741 // LOAD_INSTANCE in parallel
742 // add placeholder entry even if error - callers will remove on error
743 if (!throw_circularity_error && !class_has_been_loaded) {
744 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
745 // For class loaders that do not acquire the classloader object lock,
746 // if they did not catch another thread holding LOAD_INSTANCE,
747 // need a check analogous to the acquire ObjectLocker/find_class
748 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
749 // one final check if the load has already completed
750 // class loaders holding the ObjectLock shouldn't find the class here
751 Klass* check = find_class(d_index, d_hash, name, loader_data);
752 if (check != NULL) {
753 // Klass is already loaded, so just return it
754 k = instanceKlassHandle(THREAD, check);
755 class_has_been_loaded = true;
756 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
757 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
758 SystemDictionary_lock->notify_all();
759 }
760 }
761 }
762 // must throw error outside of owning lock
763 if (throw_circularity_error) {
764 ResourceMark rm(THREAD);
765 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
766 }
767
768 if (!class_has_been_loaded) {
769
770 // Do actual loading
771 k = load_instance_class(name, class_loader, THREAD);
772
773 // For UnsyncloadClass only
774 // If they got a linkageError, check if a parallel class load succeeded.
775 // If it did, then for bytecode resolution the specification requires
776 // that we return the same result we did for the other thread, i.e. the
777 // successfully loaded InstanceKlass
778 // Should not get here for classloaders that support parallelism
779 // with the new cleaner mechanism, even with AllowParallelDefineClass
780 // Bootstrap goes through here to allow for an extra guarantee check
781 if (UnsyncloadClass || (class_loader.is_null())) {
782 if (k.is_null() && HAS_PENDING_EXCEPTION
783 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
784 MutexLocker mu(SystemDictionary_lock, THREAD);
785 Klass* check = find_class(d_index, d_hash, name, loader_data);
786 if (check != NULL) {
787 // Klass is already loaded, so just use it
788 k = instanceKlassHandle(THREAD, check);
789 CLEAR_PENDING_EXCEPTION;
790 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
791 }
792 }
793 }
794
795 // clean up placeholder entries for success or error
796 // This cleans up LOAD_INSTANCE entries
797 // It also cleans up LOAD_SUPER entries on errors from
798 // calling load_instance_class
799 {
800 MutexLocker mu(SystemDictionary_lock, THREAD);
801 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
802 if (probe != NULL) {
803 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
804 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
805 SystemDictionary_lock->notify_all();
806 }
807 }
808
809 // If everything was OK (no exceptions, no null return value), and
810 // class_loader is NOT the defining loader, do a little more bookkeeping.
811 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
812 k->class_loader() != class_loader()) {
813
814 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
815
816 // Need to check for a PENDING_EXCEPTION again; check_constraints
817 // can throw and doesn't use the CHECK macro.
818 if (!HAS_PENDING_EXCEPTION) {
819 { // Grabbing the Compile_lock prevents systemDictionary updates
820 // during compilations.
821 MutexLocker mu(Compile_lock, THREAD);
822 update_dictionary(d_index, d_hash, p_index, p_hash,
823 k, class_loader, THREAD);
824 }
825 if (JvmtiExport::should_post_class_load()) {
826 Thread *thread = THREAD;
827 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
828 JvmtiExport::post_class_load((JavaThread *) thread, k());
829 }
830 }
831 }
832 if (HAS_PENDING_EXCEPTION || k.is_null()) {
833 // On error, clean up placeholders
834 {
835 MutexLocker mu(SystemDictionary_lock, THREAD);
836 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
837 SystemDictionary_lock->notify_all();
838 }
839 return NULL;
840 }
841 }
842 }
843
844 #ifdef ASSERT
845 {
846 ClassLoaderData* loader_data = k->class_loader_data();
847 MutexLocker mu(SystemDictionary_lock, THREAD);
848 Klass* kk = find_class(name, loader_data);
849 assert(kk == k(), "should be present in dictionary");
850 }
851 #endif
852
853 // return if the protection domain in NULL
854 if (protection_domain() == NULL) return k();
855
856 // Check the protection domain has the right access
857 {
858 MutexLocker mu(SystemDictionary_lock, THREAD);
859 // Note that we have an entry, and entries can be deleted only during GC,
860 // so we cannot allow GC to occur while we're holding this entry.
861 // We're using a No_Safepoint_Verifier to catch any place where we
862 // might potentially do a GC at all.
863 // SystemDictionary::do_unloading() asserts that classes are only
864 // unloaded at a safepoint.
865 No_Safepoint_Verifier nosafepoint;
866 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
867 loader_data,
868 protection_domain)) {
869 return k();
870 }
871 }
872
873 // Verify protection domain. If it fails an exception is thrown
874 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
875
876 return k();
877 }
878
879
880 // This routine does not lock the system dictionary.
881 //
882 // Since readers don't hold a lock, we must make sure that system
883 // dictionary entries are only removed at a safepoint (when only one
884 // thread is running), and are added to in a safe way (all links must
885 // be updated in an MT-safe manner).
886 //
887 // Callers should be aware that an entry could be added just after
888 // _dictionary->bucket(index) is read here, so the caller will not see
889 // the new entry.
890
891 Klass* SystemDictionary::find(Symbol* class_name,
892 Handle class_loader,
893 Handle protection_domain,
894 TRAPS) {
895
896 // UseNewReflection
897 // The result of this call should be consistent with the result
898 // of the call to resolve_instance_class_or_null().
899 // See evaluation 6790209 and 4474172 for more details.
900 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
901 ClassLoaderData* loader_data = register_loader(class_loader);
902
903 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
904 int d_index = dictionary()->hash_to_index(d_hash);
905
906 {
907 // Note that we have an entry, and entries can be deleted only during GC,
908 // so we cannot allow GC to occur while we're holding this entry.
909 // We're using a No_Safepoint_Verifier to catch any place where we
910 // might potentially do a GC at all.
911 // SystemDictionary::do_unloading() asserts that classes are only
912 // unloaded at a safepoint.
913 No_Safepoint_Verifier nosafepoint;
914 return dictionary()->find(d_index, d_hash, class_name, loader_data,
915 protection_domain, THREAD);
916 }
917 }
918
919
920 // Look for a loaded instance or array klass by name. Do not do any loading.
921 // return NULL in case of error.
922 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
923 Handle class_loader,
924 Handle protection_domain,
925 TRAPS) {
926 Klass* k = NULL;
927 assert(class_name != NULL, "class name must be non NULL");
928
929 // Try to get one of the well-known klasses.
930 if (LinkWellKnownClasses) {
931 k = find_well_known_klass(class_name);
932 if (k != NULL) {
933 return k;
934 }
935 }
936
937 if (FieldType::is_array(class_name)) {
938 // The name refers to an array. Parse the name.
939 // dimension and object_key in FieldArrayInfo are assigned as a
940 // side-effect of this call
941 FieldArrayInfo fd;
942 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
943 if (t != T_OBJECT) {
944 k = Universe::typeArrayKlassObj(t);
945 } else {
946 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
947 }
948 if (k != NULL) {
949 k = Klass::cast(k)->array_klass_or_null(fd.dimension());
950 }
951 } else {
952 k = find(class_name, class_loader, protection_domain, THREAD);
953 }
954 return k;
955 }
956
957 // Quick range check for names of well-known classes:
958 static Symbol* wk_klass_name_limits[2] = {NULL, NULL};
959
960 #ifndef PRODUCT
961 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
962 // counts for "hello world": 3983, 1616, 1075
963 // => 60% hit after limit guard, 25% total win rate
964 #endif
965
966 Klass* SystemDictionary::find_well_known_klass(Symbol* class_name) {
967 // A bounds-check on class_name will quickly get a negative result.
968 NOT_PRODUCT(find_wkk_calls++);
969 if (class_name >= wk_klass_name_limits[0] &&
970 class_name <= wk_klass_name_limits[1]) {
971 NOT_PRODUCT(find_wkk_probes++);
972 vmSymbols::SID sid = vmSymbols::find_sid(class_name);
973 if (sid != vmSymbols::NO_SID) {
974 Klass* k = NULL;
975 switch (sid) {
976 #define WK_KLASS_CASE(name, symbol, ignore_option) \
977 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
978 k = WK_KLASS(name); break;
979 WK_KLASSES_DO(WK_KLASS_CASE)
980 #undef WK_KLASS_CASE
981 }
982 NOT_PRODUCT(if (k != NULL) find_wkk_wins++);
983 return k;
984 }
985 }
986 return NULL;
987 }
988
989 // Note: this method is much like resolve_from_stream, but
990 // updates no supplemental data structures.
991 // TODO consolidate the two methods with a helper routine?
992 Klass* SystemDictionary::parse_stream(Symbol* class_name,
993 Handle class_loader,
994 Handle protection_domain,
995 ClassFileStream* st,
996 KlassHandle host_klass,
997 GrowableArray<Handle>* cp_patches,
998 TRAPS) {
999 TempNewSymbol parsed_name = NULL;
1000
1001 // Parse the stream. Note that we do this even though this klass might
1002 // already be present in the SystemDictionary, otherwise we would not
1003 // throw potential ClassFormatErrors.
1004 //
1005 // Note: "name" is updated.
1006 // Further note: a placeholder will be added for this class when
1007 // super classes are loaded (resolve_super_or_fail). We expect this
1008 // to be called for all classes but java.lang.Object; and we preload
1009 // java.lang.Object through resolve_or_fail, not this path.
1010
1011 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1012 class_loader,
1013 protection_domain,
1014 host_klass,
1015 cp_patches,
1016 parsed_name,
1017 true,
1018 THREAD);
1019
1020 // We don't redefine the class, so we just need to clean up whether there
1021 // was an error or not (don't want to modify any system dictionary
1022 // data structures).
1023 // Parsed name could be null if we threw an error before we got far
1024 // enough along to parse it -- in that case, there is nothing to clean up.
1025 if (parsed_name != NULL) {
1026 ClassLoaderData* loader_data = class_loader_data(class_loader);
1027
1028 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1029 loader_data);
1030 int p_index = placeholders()->hash_to_index(p_hash);
1031 {
1032 MutexLocker mu(SystemDictionary_lock, THREAD);
1033 placeholders()->find_and_remove(p_index, p_hash, parsed_name, loader_data, THREAD);
1034 SystemDictionary_lock->notify_all();
1035 }
1036 }
1037
1038 if (host_klass.not_null() && k.not_null()) {
1039 assert(EnableInvokeDynamic, "");
1040 // If it's anonymous, initialize it now, since nobody else will.
1041 k->class_loader_data()->record_dependency(host_klass(), CHECK_NULL);
1042 k->set_host_klass(host_klass());
1043
1044 {
1045 MutexLocker mu_r(Compile_lock, THREAD);
1046
1047 // Add to class hierarchy, initialize vtables, and do possible
1048 // deoptimizations.
1049 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1050
1051 // But, do not add to system dictionary.
1052 }
1053
1054 // Rewrite and patch constant pool here.
1055 k->link_class(THREAD);
1056 if (cp_patches != NULL) {
1057 k->constants()->patch_resolved_references(cp_patches);
1058 }
1059 k->eager_initialize(THREAD);
1060
1061 // notify jvmti
1062 if (JvmtiExport::should_post_class_load()) {
1063 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1064 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1065 }
1066 }
1067 assert(host_klass.not_null() || cp_patches == NULL,
1068 "cp_patches only found with host_klass");
1069
1070 return k();
1071 }
1072
1073 // Add a klass to the system from a stream (called by jni_DefineClass and
1074 // JVM_DefineClass).
1075 // Note: class_name can be NULL. In that case we do not know the name of
1076 // the class until we have parsed the stream.
1077
1078 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1079 Handle class_loader,
1080 Handle protection_domain,
1081 ClassFileStream* st,
1082 bool verify,
1083 TRAPS) {
1084
1085 // Classloaders that support parallelism, e.g. bootstrap classloader,
1086 // or all classloaders with UnsyncloadClass do not acquire lock here
1087 bool DoObjectLock = true;
1088 if (is_parallelCapable(class_loader)) {
1089 DoObjectLock = false;
1090 }
1091
1092 ClassLoaderData* loader_data = register_loader(class_loader);
1093
1094 // Make sure we are synchronized on the class loader before we proceed
1095 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1096 check_loader_lock_contention(lockObject, THREAD);
1097 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1098
1099 TempNewSymbol parsed_name = NULL;
1100
1101 // Parse the stream. Note that we do this even though this klass might
1102 // already be present in the SystemDictionary, otherwise we would not
1103 // throw potential ClassFormatErrors.
1104 //
1105 // Note: "name" is updated.
1106 // Further note: a placeholder will be added for this class when
1107 // super classes are loaded (resolve_super_or_fail). We expect this
1108 // to be called for all classes but java.lang.Object; and we preload
1109 // java.lang.Object through resolve_or_fail, not this path.
1110
1111 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1112 class_loader,
1113 protection_domain,
1114 parsed_name,
1115 verify,
1116 THREAD);
1117
1118 const char* pkg = "java/";
1119 if (!HAS_PENDING_EXCEPTION &&
1120 !class_loader.is_null() &&
1121 parsed_name != NULL &&
1122 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1123 // It is illegal to define classes in the "java." package from
1124 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1125 ResourceMark rm(THREAD);
1126 char* name = parsed_name->as_C_string();
1127 char* index = strrchr(name, '/');
1128 *index = '\0'; // chop to just the package name
1129 while ((index = strchr(name, '/')) != NULL) {
1130 *index = '.'; // replace '/' with '.' in package name
1131 }
1132 const char* fmt = "Prohibited package name: %s";
1133 size_t len = strlen(fmt) + strlen(name);
1134 char* message = NEW_RESOURCE_ARRAY(char, len);
1135 jio_snprintf(message, len, fmt, name);
1136 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1137 vmSymbols::java_lang_SecurityException(), message);
1138 }
1139
1140 if (!HAS_PENDING_EXCEPTION) {
1141 assert(parsed_name != NULL, "Sanity");
1142 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1143 // Verification prevents us from creating names with dots in them, this
1144 // asserts that that's the case.
1145 assert(is_internal_format(parsed_name),
1146 "external class name format used internally");
1147
1148 // Add class just loaded
1149 // If a class loader supports parallel classloading handle parallel define requests
1150 // find_or_define_instance_class may return a different InstanceKlass
1151 if (is_parallelCapable(class_loader)) {
1152 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1153 } else {
1154 define_instance_class(k, THREAD);
1155 }
1156 }
1157
1158 // If parsing the class file or define_instance_class failed, we
1159 // need to remove the placeholder added on our behalf. But we
1160 // must make sure parsed_name is valid first (it won't be if we had
1161 // a format error before the class was parsed far enough to
1162 // find the name).
1163 if (HAS_PENDING_EXCEPTION && parsed_name != NULL) {
1164 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1165 loader_data);
1166 int p_index = placeholders()->hash_to_index(p_hash);
1167 {
1168 MutexLocker mu(SystemDictionary_lock, THREAD);
1169 placeholders()->find_and_remove(p_index, p_hash, parsed_name, loader_data, THREAD);
1170 SystemDictionary_lock->notify_all();
1171 }
1172 return NULL;
1173 }
1174
1175 // Make sure that we didn't leave a place holder in the
1176 // SystemDictionary; this is only done on success
1177 debug_only( {
1178 if (!HAS_PENDING_EXCEPTION) {
1179 assert(parsed_name != NULL, "parsed_name is still null?");
1180 Symbol* h_name = k->name();
1181 ClassLoaderData *defining_loader_data = k->class_loader_data();
1182
1183 MutexLocker mu(SystemDictionary_lock, THREAD);
1184
1185 Klass* check = find_class(parsed_name, loader_data);
1186 assert(check == k(), "should be present in the dictionary");
1187
1188 Klass* check2 = find_class(h_name, defining_loader_data);
1189 assert(check == check2, "name inconsistancy in SystemDictionary");
1190 }
1191 } );
1192
1193 return k();
1194 }
1195
1196
1197 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1198 int number_of_entries) {
1199 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1200 "bad shared dictionary size.");
1201 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1202 }
1203
1204
1205 // If there is a shared dictionary, then find the entry for the
1206 // given shared system class, if any.
1207
1208 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1209 if (shared_dictionary() != NULL) {
1210 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1211 int d_index = shared_dictionary()->hash_to_index(d_hash);
1212
1213 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1214 } else {
1215 return NULL;
1216 }
1217 }
1218
1219
1220 // Load a class from the shared spaces (found through the shared system
1221 // dictionary). Force the superclass and all interfaces to be loaded.
1222 // Update the class definition to include sibling classes and no
1223 // subclasses (yet). [Classes in the shared space are not part of the
1224 // object hierarchy until loaded.]
1225
1226 instanceKlassHandle SystemDictionary::load_shared_class(
1227 Symbol* class_name, Handle class_loader, TRAPS) {
1228 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1229 return load_shared_class(ik, class_loader, THREAD);
1230 }
1231
1232 // Note well! Changes to this method may affect oop access order
1233 // in the shared archive. Please take care to not make changes that
1234 // adversely affect cold start time by changing the oop access order
1235 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1236 // MarkAndMoveOrderedReadWrite closures.
1237 instanceKlassHandle SystemDictionary::load_shared_class(
1238 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1239 assert(class_loader.is_null(), "non-null classloader for shared class?");
1240 if (ik.not_null()) {
1241 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1242 Symbol* class_name = ik->name();
1243
1244 // Found the class, now load the superclass and interfaces. If they
1245 // are shared, add them to the main system dictionary and reset
1246 // their hierarchy references (supers, subs, and interfaces).
1247
1248 if (ik->super() != NULL) {
1249 Symbol* cn = ik->super()->name();
1250 resolve_super_or_fail(class_name, cn,
1251 class_loader, Handle(), true, CHECK_(nh));
1252 }
1253
1254 Array<Klass*>* interfaces = ik->local_interfaces();
1255 int num_interfaces = interfaces->length();
1256 for (int index = 0; index < num_interfaces; index++) {
1257 Klass* k = interfaces->at(index);
1258
1259 // Note: can not use InstanceKlass::cast here because
1260 // interfaces' InstanceKlass's C++ vtbls haven't been
1261 // reinitialized yet (they will be once the interface classes
1262 // are loaded)
1263 Symbol* name = k->name();
1264 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1265 }
1266
1267 // Adjust methods to recover missing data. They need addresses for
1268 // interpreter entry points and their default native method address
1269 // must be reset.
1270
1271 // Updating methods must be done under a lock so multiple
1272 // threads don't update these in parallel
1273 // Shared classes are all currently loaded by the bootstrap
1274 // classloader, so this will never cause a deadlock on
1275 // a custom class loader lock.
1276
1277 {
1278 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1279 check_loader_lock_contention(lockObject, THREAD);
1280 ObjectLocker ol(lockObject, THREAD, true);
1281 ik->restore_unshareable_info(CHECK_(nh));
1282 }
1283
1284 if (TraceClassLoading) {
1285 ResourceMark rm;
1286 tty->print("[Loaded %s", ik->external_name());
1287 tty->print(" from shared objects file");
1288 tty->print_cr("]");
1289 }
1290 // notify a class loaded from shared object
1291 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1292 true /* shared class */);
1293 }
1294 return ik;
1295 }
1296
1297 #ifdef KERNEL
1298 // Some classes on the bootstrap class path haven't been installed on the
1299 // system yet. Call the DownloadManager method to make them appear in the
1300 // bootstrap class path and try again to load the named class.
1301 // Note that with delegation class loaders all classes in another loader will
1302 // first try to call this so it'd better be fast!!
1303 static instanceKlassHandle download_and_retry_class_load(
1304 Symbol* class_name,
1305 TRAPS) {
1306
1307 Klass* dlm = SystemDictionary::DownloadManager_klass();
1308 instanceKlassHandle nk;
1309
1310 // If download manager class isn't loaded just return.
1311 if (dlm == NULL) return nk;
1312
1313 { HandleMark hm(THREAD);
1314 ResourceMark rm(THREAD);
1315 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1316 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1317
1318 // return value
1319 JavaValue result(T_OBJECT);
1320
1321 // Call the DownloadManager. We assume that it has a lock because
1322 // multiple classes could be not found and downloaded at the same time.
1323 // class sun.misc.DownloadManager;
1324 // public static String getBootClassPathEntryForClass(String className);
1325 JavaCalls::call_static(&result,
1326 KlassHandle(THREAD, dlm),
1327 vmSymbols::getBootClassPathEntryForClass_name(),
1328 vmSymbols::string_string_signature(),
1329 class_string,
1330 CHECK_(nk));
1331
1332 // Get result.string and add to bootclasspath
1333 assert(result.get_type() == T_OBJECT, "just checking");
1334 oop obj = (oop) result.get_jobject();
1335 if (obj == NULL) { return nk; }
1336
1337 Handle h_obj(THREAD, obj);
1338 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1339 CHECK_(nk));
1340
1341 // lock the loader
1342 // we use this lock because JVMTI does.
1343 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1344
1345 ObjectLocker ol(loader_lock, THREAD);
1346 // add the file to the bootclasspath
1347 ClassLoader::update_class_path_entry_list(new_class_name, true);
1348 } // end HandleMark
1349
1350 if (TraceClassLoading) {
1351 ClassLoader::print_bootclasspath();
1352 }
1353 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1354 }
1355 #endif // KERNEL
1356
1357
1358 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1359 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1360 if (class_loader.is_null()) {
1361
1362 // Search the shared system dictionary for classes preloaded into the
1363 // shared spaces.
1364 instanceKlassHandle k;
1365 {
1366 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1367 k = load_shared_class(class_name, class_loader, THREAD);
1368 }
1369
1370 if (k.is_null()) {
1371 // Use VM class loader
1372 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1373 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1374 }
1375
1376 #ifdef KERNEL
1377 // If the VM class loader has failed to load the class, call the
1378 // DownloadManager class to make it magically appear on the classpath
1379 // and try again. This is only configured with the Kernel VM.
1380 if (k.is_null()) {
1381 k = download_and_retry_class_load(class_name, CHECK_(nh));
1382 }
1383 #endif // KERNEL
1384
1385 // find_or_define_instance_class may return a different InstanceKlass
1386 if (!k.is_null()) {
1387 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1388 }
1389 return k;
1390 } else {
1391 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1392 ResourceMark rm(THREAD);
1393
1394 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1395 JavaThread* jt = (JavaThread*) THREAD;
1396
1397 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1398 ClassLoader::perf_app_classload_selftime(),
1399 ClassLoader::perf_app_classload_count(),
1400 jt->get_thread_stat()->perf_recursion_counts_addr(),
1401 jt->get_thread_stat()->perf_timers_addr(),
1402 PerfClassTraceTime::CLASS_LOAD);
1403
1404 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1405 // Translate to external class name format, i.e., convert '/' chars to '.'
1406 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1407
1408 JavaValue result(T_OBJECT);
1409
1410 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1411
1412 // Call public unsynchronized loadClass(String) directly for all class loaders
1413 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1414 // acquire a class-name based lock rather than the class loader object lock.
1415 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1416 // so the call to loadClassInternal() was not required.
1417 //
1418 // UnsyncloadClass flag means both call loadClass(String) and do
1419 // not acquire the class loader lock even for class loaders that are
1420 // not parallelCapable. This was a risky transitional
1421 // flag for diagnostic purposes only. It is risky to call
1422 // custom class loaders without synchronization.
1423 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1424 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1425 // Do NOT assume this will be supported in future releases.
1426 //
1427 // Added MustCallLoadClassInternal in case we discover in the field
1428 // a customer that counts on this call
1429 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1430 JavaCalls::call_special(&result,
1431 class_loader,
1432 spec_klass,
1433 vmSymbols::loadClassInternal_name(),
1434 vmSymbols::string_class_signature(),
1435 string,
1436 CHECK_(nh));
1437 } else {
1438 JavaCalls::call_virtual(&result,
1439 class_loader,
1440 spec_klass,
1441 vmSymbols::loadClass_name(),
1442 vmSymbols::string_class_signature(),
1443 string,
1444 CHECK_(nh));
1445 }
1446
1447 assert(result.get_type() == T_OBJECT, "just checking");
1448 oop obj = (oop) result.get_jobject();
1449
1450 // Primitive classes return null since forName() can not be
1451 // used to obtain any of the Class objects representing primitives or void
1452 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1453 instanceKlassHandle k =
1454 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1455 // For user defined Java class loaders, check that the name returned is
1456 // the same as that requested. This check is done for the bootstrap
1457 // loader when parsing the class file.
1458 if (class_name == k->name()) {
1459 return k;
1460 }
1461 }
1462 // Class is not found or has the wrong name, return NULL
1463 return nh;
1464 }
1465 }
1466
1467 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1468
1469 ClassLoaderData* loader_data = k->class_loader_data();
1470 Handle class_loader_h(THREAD, loader_data->class_loader());
1471
1472 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1473
1474 // for bootstrap and other parallel classloaders don't acquire lock,
1475 // use placeholder token
1476 // If a parallelCapable class loader calls define_instance_class instead of
1477 // find_or_define_instance_class to get here, we have a timing
1478 // hole with systemDictionary updates and check_constraints
1479 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1480 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1481 compute_loader_lock_object(class_loader_h, THREAD)),
1482 "define called without lock");
1483 }
1484
1485 // Check class-loading constraints. Throw exception if violation is detected.
1486 // Grabs and releases SystemDictionary_lock
1487 // The check_constraints/find_class call and update_dictionary sequence
1488 // must be "atomic" for a specific class/classloader pair so we never
1489 // define two different instanceKlasses for that class/classloader pair.
1490 // Existing classloaders will call define_instance_class with the
1491 // classloader lock held
1492 // Parallel classloaders will call find_or_define_instance_class
1493 // which will require a token to perform the define class
1494 Symbol* name_h = k->name();
1495 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1496 int d_index = dictionary()->hash_to_index(d_hash);
1497 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1498
1499 // Register class just loaded with class loader (placed in Vector)
1500 // Note we do this before updating the dictionary, as this can
1501 // fail with an OutOfMemoryError (if it does, we will *not* put this
1502 // class in the dictionary and will not update the class hierarchy).
1503 // JVMTI FollowReferences needs to find the classes this way.
1504 if (k->class_loader() != NULL) {
1505 methodHandle m(THREAD, Universe::loader_addClass_method());
1506 JavaValue result(T_VOID);
1507 JavaCallArguments args(class_loader_h);
1508 args.push_oop(Handle(THREAD, k->java_mirror()));
1509 JavaCalls::call(&result, m, &args, CHECK);
1510 }
1511
1512 // Add the new class. We need recompile lock during update of CHA.
1513 {
1514 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1515 int p_index = placeholders()->hash_to_index(p_hash);
1516
1517 MutexLocker mu_r(Compile_lock, THREAD);
1518
1519 // Add to class hierarchy, initialize vtables, and do possible
1520 // deoptimizations.
1521 add_to_hierarchy(k, CHECK); // No exception, but can block
1522
1523 // Add to systemDictionary - so other classes can see it.
1524 // Grabs and releases SystemDictionary_lock
1525 update_dictionary(d_index, d_hash, p_index, p_hash,
1526 k, class_loader_h, THREAD);
1527 }
1528 k->eager_initialize(THREAD);
1529
1530 // notify jvmti
1531 if (JvmtiExport::should_post_class_load()) {
1532 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1533 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1534
1535 }
1536 }
1537
1538 // Support parallel classloading
1539 // All parallel class loaders, including bootstrap classloader
1540 // lock a placeholder entry for this class/class_loader pair
1541 // to allow parallel defines of different classes for this class loader
1542 // With AllowParallelDefine flag==true, in case they do not synchronize around
1543 // FindLoadedClass/DefineClass, calls, we check for parallel
1544 // loading for them, wait if a defineClass is in progress
1545 // and return the initial requestor's results
1546 // This flag does not apply to the bootstrap classloader.
1547 // With AllowParallelDefine flag==false, call through to define_instance_class
1548 // which will throw LinkageError: duplicate class definition.
1549 // False is the requested default.
1550 // For better performance, the class loaders should synchronize
1551 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1552 // potentially waste time reading and parsing the bytestream.
1553 // Note: VM callers should ensure consistency of k/class_name,class_loader
1554 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1555
1556 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1557 Symbol* name_h = k->name(); // passed in class_name may be null
1558 ClassLoaderData* loader_data = class_loader_data(class_loader);
1559
1560 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1561 int d_index = dictionary()->hash_to_index(d_hash);
1562
1563 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1564 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1565 int p_index = placeholders()->hash_to_index(p_hash);
1566 PlaceholderEntry* probe;
1567
1568 {
1569 MutexLocker mu(SystemDictionary_lock, THREAD);
1570 // First check if class already defined
1571 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1572 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1573 if (check != NULL) {
1574 return(instanceKlassHandle(THREAD, check));
1575 }
1576 }
1577
1578 // Acquire define token for this class/classloader
1579 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1580 // Wait if another thread defining in parallel
1581 // All threads wait - even those that will throw duplicate class: otherwise
1582 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1583 // if other thread has not finished updating dictionary
1584 while (probe->definer() != NULL) {
1585 SystemDictionary_lock->wait();
1586 }
1587 // Only special cases allow parallel defines and can use other thread's results
1588 // Other cases fall through, and may run into duplicate defines
1589 // caught by finding an entry in the SystemDictionary
1590 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->InstanceKlass() != NULL)) {
1591 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1592 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, THREAD);
1593 SystemDictionary_lock->notify_all();
1594 #ifdef ASSERT
1595 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1596 assert(check != NULL, "definer missed recording success");
1597 #endif
1598 return(instanceKlassHandle(THREAD, probe->InstanceKlass()));
1599 } else {
1600 // This thread will define the class (even if earlier thread tried and had an error)
1601 probe->set_definer(THREAD);
1602 }
1603 }
1604
1605 define_instance_class(k, THREAD);
1606
1607 Handle linkage_exception = Handle(); // null handle
1608
1609 // definer must notify any waiting threads
1610 {
1611 MutexLocker mu(SystemDictionary_lock, THREAD);
1612 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1613 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1614 if (probe != NULL) {
1615 if (HAS_PENDING_EXCEPTION) {
1616 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1617 CLEAR_PENDING_EXCEPTION;
1618 } else {
1619 probe->set_instanceKlass(k());
1620 }
1621 probe->set_definer(NULL);
1622 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1623 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, THREAD);
1624 SystemDictionary_lock->notify_all();
1625 }
1626 }
1627
1628 // Can't throw exception while holding lock due to rank ordering
1629 if (linkage_exception() != NULL) {
1630 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1631 }
1632
1633 return k;
1634 }
1635 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1636 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1637 if (class_loader.is_null()) {
1638 return Handle(THREAD, _system_loader_lock_obj);
1639 } else {
1640 return class_loader;
1641 }
1642 }
1643
1644 // This method is added to check how often we have to wait to grab loader
1645 // lock. The results are being recorded in the performance counters defined in
1646 // ClassLoader::_sync_systemLoaderLockContentionRate and
1647 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1648 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1649 if (!UsePerfData) {
1650 return;
1651 }
1652
1653 assert(!loader_lock.is_null(), "NULL lock object");
1654
1655 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1656 == ObjectSynchronizer::owner_other) {
1657 // contention will likely happen, so increment the corresponding
1658 // contention counter.
1659 if (loader_lock() == _system_loader_lock_obj) {
1660 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1661 } else {
1662 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1663 }
1664 }
1665 }
1666
1667 // ----------------------------------------------------------------------------
1668 // Lookup
1669
1670 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1671 Symbol* class_name,
1672 ClassLoaderData* loader_data) {
1673 assert_locked_or_safepoint(SystemDictionary_lock);
1674 assert (index == dictionary()->index_for(class_name, loader_data),
1675 "incorrect index?");
1676
1677 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1678 return k;
1679 }
1680
1681
1682 // Basic find on classes in the midst of being loaded
1683 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1684 ClassLoaderData* loader_data) {
1685 assert_locked_or_safepoint(SystemDictionary_lock);
1686 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1687 int p_index = placeholders()->hash_to_index(p_hash);
1688 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1689 }
1690
1691
1692 // Used for assertions and verification only
1693 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1694 #ifndef ASSERT
1695 guarantee(VerifyBeforeGC ||
1696 VerifyDuringGC ||
1697 VerifyBeforeExit ||
1698 VerifyAfterGC, "too expensive");
1699 #endif
1700 assert_locked_or_safepoint(SystemDictionary_lock);
1701
1702 // First look in the loaded class array
1703 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1704 int d_index = dictionary()->hash_to_index(d_hash);
1705 return find_class(d_index, d_hash, class_name, loader_data);
1706 }
1707
1708
1709 // Get the next class in the diictionary.
1710 Klass* SystemDictionary::try_get_next_class() {
1711 return dictionary()->try_get_next_class();
1712 }
1713
1714
1715 // ----------------------------------------------------------------------------
1716 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1717 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1718 // before a new class is used.
1719
1720 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1721 assert(k.not_null(), "just checking");
1722 assert_locked_or_safepoint(Compile_lock);
1723
1724 // Link into hierachy. Make sure the vtables are initialized before linking into
1725 k->append_to_sibling_list(); // add to superklass/sibling list
1726 k->process_interfaces(THREAD); // handle all "implements" declarations
1727 k->set_init_state(InstanceKlass::loaded);
1728 // Now flush all code that depended on old class hierarchy.
1729 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1730 // Also, first reinitialize vtable because it may have gotten out of synch
1731 // while the new class wasn't connected to the class hierarchy.
1732 Universe::flush_dependents_on(k);
1733 }
1734
1735
1736 // ----------------------------------------------------------------------------
1737 // GC support
1738
1739 // Following roots during mark-sweep is separated in two phases.
1740 //
1741 // The first phase follows preloaded classes and all other system
1742 // classes, since these will never get unloaded anyway.
1743 //
1744 // The second phase removes (unloads) unreachable classes from the
1745 // system dictionary and follows the remaining classes' contents.
1746
1747 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1748 blk->do_oop(&_java_system_loader);
1749 blk->do_oop(&_system_loader_lock_obj);
1750
1751 dictionary()->always_strong_oops_do(blk);
1752 }
1753
1754 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1755 // Follow all system classes and temporary placeholders in dictionary
1756 dictionary()->always_strong_classes_do(closure);
1757
1758 // Placeholders. These represent classes we're actively loading.
1759 placeholders()->classes_do(closure);
1760 }
1761
1762 // Calculate a "good" systemdictionary size based
1763 // on predicted or current loaded classes count
1764 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1765 int newsize = _old_default_sdsize;
1766 if ((classcount > 0) && !DumpSharedSpaces) {
1767 int desiredsize = classcount/_average_depth_goal;
1768 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1769 newsize = _primelist[++_sdgeneration]) {
1770 if (desiredsize <= newsize) {
1771 break;
1772 }
1773 }
1774 }
1775 return newsize;
1776 }
1777 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1778 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1779 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1780 bool unloading_occurred = false;
1781 if (has_dead_loaders) {
1782 unloading_occurred = dictionary()->do_unloading();
1783 constraints()->purge_loader_constraints();
1784 resolution_errors()->purge_resolution_errors();
1785 }
1786 return unloading_occurred;
1787 }
1788
1789 void SystemDictionary::oops_do(OopClosure* f) {
1790 f->do_oop(&_java_system_loader);
1791 f->do_oop(&_system_loader_lock_obj);
1792
1793 // Adjust dictionary
1794 dictionary()->oops_do(f);
1795
1796 // Visit extra methods
1797 invoke_method_table()->oops_do(f);
1798 }
1799
1800 // Extended Class redefinition support.
1801 // If one of these classes is replaced, we need to replace it in these places.
1802 // KlassClosure::do_klass should take the address of a class but we can
1803 // change that later.
1804 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1805 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1806 f->do_klass(_well_known_klasses[k]);
1807 }
1808
1809 {
1810 for (int i = 0; i < T_VOID+1; i++) {
1811 if (_box_klasses[i] != NULL) {
1812 assert(i >= T_BOOLEAN, "checking");
1813 f->do_klass(_box_klasses[i]);
1814 }
1815 }
1816 }
1817
1818 FilteredFieldsMap::classes_do(f);
1819 }
1820
1821 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1822 f->do_klass(_abstract_ownable_synchronizer_klass);
1823 }
1824
1825 // Just the classes from defining class loaders
1826 // Don't iterate over placeholders
1827 void SystemDictionary::classes_do(void f(Klass*)) {
1828 dictionary()->classes_do(f);
1829 }
1830
1831 // Added for initialize_itable_for_klass
1832 // Just the classes from defining class loaders
1833 // Don't iterate over placeholders
1834 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1835 dictionary()->classes_do(f, CHECK);
1836 }
1837
1838 // All classes, and their class loaders
1839 // Don't iterate over placeholders
1840 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1841 dictionary()->classes_do(f);
1842 }
1843
1844 // All classes, and their class loaders
1845 // (added for helpers that use HandleMarks and ResourceMarks)
1846 // Don't iterate over placeholders
1847 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) {
1848 dictionary()->classes_do(f, CHECK);
1849 }
1850
1851 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1852 placeholders()->entries_do(f);
1853 }
1854
1855 void SystemDictionary::methods_do(void f(Method*)) {
1856 dictionary()->methods_do(f);
1857 invoke_method_table()->methods_do(f);
1858 }
1859
1860 // ----------------------------------------------------------------------------
1861 // Lazily load klasses
1862
1863 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1864 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1865
1866 // if multiple threads calling this function, only one thread will load
1867 // the class. The other threads will find the loaded version once the
1868 // class is loaded.
1869 Klass* aos = _abstract_ownable_synchronizer_klass;
1870 if (aos == NULL) {
1871 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1872 // Force a fence to prevent any read before the write completes
1873 OrderAccess::fence();
1874 _abstract_ownable_synchronizer_klass = k;
1875 }
1876 }
1877
1878 // ----------------------------------------------------------------------------
1879 // Initialization
1880
1881 void SystemDictionary::initialize(TRAPS) {
1882 // Allocate arrays
1883 assert(dictionary() == NULL,
1884 "SystemDictionary should only be initialized once");
1885 _sdgeneration = 0;
1886 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1887 _placeholders = new PlaceholderTable(_nof_buckets);
1888 _number_of_modifications = 0;
1889 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1890 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1891 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1892
1893 // Allocate private object used as system class loader lock
1894 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1895 // Initialize basic classes
1896 initialize_preloaded_classes(CHECK);
1897 }
1898
1899 // Compact table of directions on the initialization of klasses:
1900 static const short wk_init_info[] = {
1901 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1902 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1903 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1904 | (int)SystemDictionary::option ),
1905 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1906 #undef WK_KLASS_INIT_INFO
1907 0
1908 };
1909
1910 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1911 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1912 int info = wk_init_info[id - FIRST_WKID];
1913 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1914 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1915 Klass** klassp = &_well_known_klasses[id];
1916 bool must_load = (init_opt < SystemDictionary::Opt);
1917 bool try_load = true;
1918 if (init_opt == SystemDictionary::Opt_Kernel) {
1919 #ifndef KERNEL
1920 try_load = false;
1921 #endif //KERNEL
1922 }
1923 if ((*klassp) == NULL && try_load) {
1924 if (must_load) {
1925 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1926 } else {
1927 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1928 }
1929 }
1930 return ((*klassp) != NULL);
1931 }
1932
1933 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1934 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1935 for (int id = (int)start_id; id < (int)limit_id; id++) {
1936 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1937 int info = wk_init_info[id - FIRST_WKID];
1938 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1939 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1940
1941 initialize_wk_klass((WKID)id, opt, CHECK);
1942
1943 // Update limits, so find_well_known_klass can be very fast:
1944 Symbol* s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1945 if (wk_klass_name_limits[1] == NULL) {
1946 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1947 } else if (wk_klass_name_limits[1] < s) {
1948 wk_klass_name_limits[1] = s;
1949 } else if (wk_klass_name_limits[0] > s) {
1950 wk_klass_name_limits[0] = s;
1951 }
1952 }
1953
1954 // move the starting value forward to the limit:
1955 start_id = limit_id;
1956 }
1957
1958
1959 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1960 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1961 // Preload commonly used klasses
1962 WKID scan = FIRST_WKID;
1963 // first do Object, then String, Class
1964 if (UseSharedSpaces) {
1965 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1966 // Initialize the constant pool for the Object_class
1967 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1968 ik->constants()->restore_unshareable_info(CHECK);
1969 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1970 } else {
1971 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1972 }
1973
1974 // Calculate offsets for String and Class classes since they are loaded and
1975 // can be used after this point.
1976 java_lang_String::compute_offsets();
1977 java_lang_Class::compute_offsets();
1978
1979 // Fixup mirrors for classes loaded before java.lang.Class.
1980 // These calls iterate over the objects currently in the perm gen
1981 // so calling them at this point is matters (not before when there
1982 // are fewer objects and not later after there are more objects
1983 // in the perm gen.
1984 Universe::initialize_basic_type_mirrors(CHECK);
1985 Universe::fixup_mirrors(CHECK);
1986
1987 // do a bunch more:
1988 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1989
1990 // Preload ref klasses and set reference types
1991 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1992 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1993
1994 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1995 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1996 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1997 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1998 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1999
2000 // JSR 292 classes
2001 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2002 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2003 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2004 if (EnableInvokeDynamic) {
2005 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2006 } else {
2007 // Skip the JSR 292 classes, if not enabled.
2008 scan = WKID(jsr292_group_end + 1);
2009 }
2010
2011 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
2012
2013 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2014 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2015 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2016 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2017 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2018 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2019 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2020 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2021 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2022 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2023
2024 #ifdef KERNEL
2025 if (DownloadManager_klass() == NULL) {
2026 warning("Cannot find sun/jkernel/DownloadManager");
2027 }
2028 #endif // KERNEL
2029
2030 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2031 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2032 _has_loadClassInternal = (method != NULL);
2033 }
2034 { // Compute whether we should use checkPackageAccess or NOT
2035 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2036 _has_checkPackageAccess = (method != NULL);
2037 }
2038 }
2039
2040 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2041 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2042 BasicType SystemDictionary::box_klass_type(Klass* k) {
2043 assert(k != NULL, "");
2044 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2045 if (_box_klasses[i] == k)
2046 return (BasicType)i;
2047 }
2048 return T_OBJECT;
2049 }
2050
2051 // Constraints on class loaders. The details of the algorithm can be
2052 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2053 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2054 // that the system dictionary needs to maintain a set of contraints that
2055 // must be satisfied by all classes in the dictionary.
2056 // if defining is true, then LinkageError if already in systemDictionary
2057 // if initiating loader, then ok if InstanceKlass matches existing entry
2058
2059 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2060 instanceKlassHandle k,
2061 Handle class_loader, bool defining,
2062 TRAPS) {
2063 const char *linkage_error = NULL;
2064 {
2065 Symbol* name = k->name();
2066 ClassLoaderData *loader_data = class_loader_data(class_loader);
2067
2068 MutexLocker mu(SystemDictionary_lock, THREAD);
2069
2070 Klass* check = find_class(d_index, d_hash, name, loader_data);
2071 if (check != (Klass*)NULL) {
2072 // if different InstanceKlass - duplicate class definition,
2073 // else - ok, class loaded by a different thread in parallel,
2074 // we should only have found it if it was done loading and ok to use
2075 // system dictionary only holds instance classes, placeholders
2076 // also holds array classes
2077
2078 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2079 if ((defining == true) || (k() != check)) {
2080 linkage_error = "loader (instance of %s): attempted duplicate class "
2081 "definition for name: \"%s\"";
2082 } else {
2083 return;
2084 }
2085 }
2086
2087 #ifdef ASSERT
2088 Symbol* ph_check = find_placeholder(name, loader_data);
2089 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2090 #endif
2091
2092 if (linkage_error == NULL) {
2093 if (constraints()->check_or_update(k, class_loader, name) == false) {
2094 linkage_error = "loader constraint violation: loader (instance of %s)"
2095 " previously initiated loading for a different type with name \"%s\"";
2096 }
2097 }
2098 }
2099
2100 // Throw error now if needed (cannot throw while holding
2101 // SystemDictionary_lock because of rank ordering)
2102
2103 if (linkage_error) {
2104 ResourceMark rm(THREAD);
2105 const char* class_loader_name = loader_name(class_loader());
2106 char* type_name = k->name()->as_C_string();
2107 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2108 strlen(type_name);
2109 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2110 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2111 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2112 }
2113 }
2114
2115
2116 // Update system dictionary - done after check_constraint and add_to_hierachy
2117 // have been called.
2118 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2119 int p_index, unsigned int p_hash,
2120 instanceKlassHandle k,
2121 Handle class_loader,
2122 TRAPS) {
2123 // Compile_lock prevents systemDictionary updates during compilations
2124 assert_locked_or_safepoint(Compile_lock);
2125 Symbol* name = k->name();
2126 ClassLoaderData *loader_data = class_loader_data(class_loader);
2127
2128 {
2129 MutexLocker mu1(SystemDictionary_lock, THREAD);
2130
2131 // See whether biased locking is enabled and if so set it for this
2132 // klass.
2133 // Note that this must be done past the last potential blocking
2134 // point / safepoint. We enable biased locking lazily using a
2135 // VM_Operation to iterate the SystemDictionary and installing the
2136 // biasable mark word into each InstanceKlass's prototype header.
2137 // To avoid race conditions where we accidentally miss enabling the
2138 // optimization for one class in the process of being added to the
2139 // dictionary, we must not safepoint after the test of
2140 // BiasedLocking::enabled().
2141 if (UseBiasedLocking && BiasedLocking::enabled()) {
2142 // Set biased locking bit for all loaded classes; it will be
2143 // cleared if revocation occurs too often for this type
2144 // NOTE that we must only do this when the class is initally
2145 // defined, not each time it is referenced from a new class loader
2146 if (k->class_loader() == class_loader()) {
2147 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2148 }
2149 }
2150
2151 // Assign a classid if one has not already been assigned. The
2152 // counter does not need to be atomically incremented since this
2153 // is only done while holding the SystemDictionary_lock.
2154 // All loaded classes get a unique ID.
2155 TRACE_INIT_ID(k);
2156
2157 // Check for a placeholder. If there, remove it and make a
2158 // new system dictionary entry.
2159 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
2160 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2161 if (sd_check == NULL) {
2162 dictionary()->add_klass(name, loader_data, k);
2163 notice_modification();
2164 }
2165 #ifdef ASSERT
2166 sd_check = find_class(d_index, d_hash, name, loader_data);
2167 assert (sd_check != NULL, "should have entry in system dictionary");
2168 // Changed to allow PH to remain to complete class circularity checking
2169 // while only one thread can define a class at one time, multiple
2170 // classes can resolve the superclass for a class at one time,
2171 // and the placeholder is used to track that
2172 // Symbol* ph_check = find_placeholder(name, class_loader);
2173 // assert (ph_check == NULL, "should not have a placeholder entry");
2174 #endif
2175 SystemDictionary_lock->notify_all();
2176 }
2177 }
2178
2179
2180 // Try to find a class name using the loader constraints. The
2181 // loader constraints might know about a class that isn't fully loaded
2182 // yet and these will be ignored.
2183 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2184 Symbol* class_name, Handle class_loader, TRAPS) {
2185
2186 // First see if it has been loaded directly.
2187 // Force the protection domain to be null. (This removes protection checks.)
2188 Handle no_protection_domain;
2189 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2190 no_protection_domain, CHECK_NULL);
2191 if (klass != NULL)
2192 return klass;
2193
2194 // Now look to see if it has been loaded elsewhere, and is subject to
2195 // a loader constraint that would require this loader to return the
2196 // klass that is already loaded.
2197 if (FieldType::is_array(class_name)) {
2198 // For array classes, their Klass*s are not kept in the
2199 // constraint table. The element Klass*s are.
2200 FieldArrayInfo fd;
2201 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2202 if (t != T_OBJECT) {
2203 klass = Universe::typeArrayKlassObj(t);
2204 } else {
2205 MutexLocker mu(SystemDictionary_lock, THREAD);
2206 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2207 }
2208 // If element class already loaded, allocate array klass
2209 if (klass != NULL) {
2210 klass = Klass::cast(klass)->array_klass_or_null(fd.dimension());
2211 }
2212 } else {
2213 MutexLocker mu(SystemDictionary_lock, THREAD);
2214 // Non-array classes are easy: simply check the constraint table.
2215 klass = constraints()->find_constrained_klass(class_name, class_loader);
2216 }
2217
2218 return klass;
2219 }
2220
2221
2222 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2223 Handle class_loader1,
2224 Handle class_loader2,
2225 Thread* THREAD) {
2226 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2227 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2228
2229 Symbol* constraint_name = NULL;
2230 if (!FieldType::is_array(class_name)) {
2231 constraint_name = class_name;
2232 } else {
2233 // For array classes, their Klass*s are not kept in the
2234 // constraint table. The element classes are.
2235 FieldArrayInfo fd;
2236 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2237 // primitive types always pass
2238 if (t != T_OBJECT) {
2239 return true;
2240 } else {
2241 constraint_name = fd.object_key();
2242 }
2243 }
2244 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2245 int d_index1 = dictionary()->hash_to_index(d_hash1);
2246
2247 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2248 int d_index2 = dictionary()->hash_to_index(d_hash2);
2249 {
2250 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2251
2252 // Better never do a GC while we're holding these oops
2253 No_Safepoint_Verifier nosafepoint;
2254
2255 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2256 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2257 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2258 klass2, class_loader2);
2259 }
2260 }
2261
2262 // Add entry to resolution error table to record the error when the first
2263 // attempt to resolve a reference to a class has failed.
2264 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2265 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2266 int index = resolution_errors()->hash_to_index(hash);
2267 {
2268 MutexLocker ml(SystemDictionary_lock, Thread::current());
2269 resolution_errors()->add_entry(index, hash, pool, which, error);
2270 }
2271 }
2272
2273 // Delete a resolution error for RedefineClasses for a constant pool is going away
2274 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2275 resolution_errors()->delete_entry(pool);
2276 }
2277
2278 // Lookup resolution error table. Returns error if found, otherwise NULL.
2279 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2280 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2281 int index = resolution_errors()->hash_to_index(hash);
2282 {
2283 MutexLocker ml(SystemDictionary_lock, Thread::current());
2284 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2285 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2286 }
2287 }
2288
2289
2290 // Signature constraints ensure that callers and callees agree about
2291 // the meaning of type names in their signatures. This routine is the
2292 // intake for constraints. It collects them from several places:
2293 //
2294 // * LinkResolver::resolve_method (if check_access is true) requires
2295 // that the resolving class (the caller) and the defining class of
2296 // the resolved method (the callee) agree on each type in the
2297 // method's signature.
2298 //
2299 // * LinkResolver::resolve_interface_method performs exactly the same
2300 // checks.
2301 //
2302 // * LinkResolver::resolve_field requires that the constant pool
2303 // attempting to link to a field agree with the field's defining
2304 // class about the type of the field signature.
2305 //
2306 // * klassVtable::initialize_vtable requires that, when a class
2307 // overrides a vtable entry allocated by a superclass, that the
2308 // overriding method (i.e., the callee) agree with the superclass
2309 // on each type in the method's signature.
2310 //
2311 // * klassItable::initialize_itable requires that, when a class fills
2312 // in its itables, for each non-abstract method installed in an
2313 // itable, the method (i.e., the callee) agree with the interface
2314 // on each type in the method's signature.
2315 //
2316 // All those methods have a boolean (check_access, checkconstraints)
2317 // which turns off the checks. This is used from specialized contexts
2318 // such as bootstrapping, dumping, and debugging.
2319 //
2320 // No direct constraint is placed between the class and its
2321 // supertypes. Constraints are only placed along linked relations
2322 // between callers and callees. When a method overrides or implements
2323 // an abstract method in a supertype (superclass or interface), the
2324 // constraints are placed as if the supertype were the caller to the
2325 // overriding method. (This works well, since callers to the
2326 // supertype have already established agreement between themselves and
2327 // the supertype.) As a result of all this, a class can disagree with
2328 // its supertype about the meaning of a type name, as long as that
2329 // class neither calls a relevant method of the supertype, nor is
2330 // called (perhaps via an override) from the supertype.
2331 //
2332 //
2333 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2334 //
2335 // Make sure all class components (including arrays) in the given
2336 // signature will be resolved to the same class in both loaders.
2337 // Returns the name of the type that failed a loader constraint check, or
2338 // NULL if no constraint failed. The returned C string needs cleaning up
2339 // with a ResourceMark in the caller. No exception except OOME is thrown.
2340 // Arrays are not added to the loader constraint table, their elements are.
2341 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2342 Handle loader1, Handle loader2,
2343 bool is_method, TRAPS) {
2344 // Nothing to do if loaders are the same.
2345 if (loader1() == loader2()) {
2346 return NULL;
2347 }
2348
2349 ResourceMark rm(THREAD);
2350 SignatureStream sig_strm(signature, is_method);
2351 while (!sig_strm.is_done()) {
2352 if (sig_strm.is_object()) {
2353 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2354 Symbol* sig = s;
2355 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2356 return sig->as_C_string();
2357 }
2358 }
2359 sig_strm.next();
2360 }
2361 return NULL;
2362 }
2363
2364
2365 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2366 Symbol* signature,
2367 TRAPS) {
2368 methodHandle empty;
2369 assert(EnableInvokeDynamic, "");
2370 assert(MethodHandles::is_signature_polymorphic(iid) &&
2371 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2372 iid != vmIntrinsics::_invokeGeneric,
2373 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2374
2375 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2376 int index = invoke_method_table()->hash_to_index(hash);
2377 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2378 methodHandle m;
2379 if (spe == NULL || spe->method() == NULL) {
2380 spe = NULL;
2381 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2382 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2383 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2384 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2385
2386 // Now grab the lock. We might have to throw away the new method,
2387 // if a racing thread has managed to install one at the same time.
2388 {
2389 MutexLocker ml(SystemDictionary_lock, THREAD);
2390 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2391 if (spe == NULL)
2392 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2393 if (spe->method() == NULL)
2394 spe->set_method(m());
2395 }
2396 }
2397
2398 assert(spe != NULL && spe->method() != NULL, "");
2399 return spe->method();
2400 }
2401
2402 // Helper for unpacking the return value from linkMethod and linkCallSite.
2403 static methodHandle unpack_method_and_appendix(Handle mname,
2404 objArrayHandle appendix_box,
2405 Handle* appendix_result,
2406 TRAPS) {
2407 methodHandle empty;
2408 if (mname.not_null()) {
2409 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2410 if (vmtarget != NULL && vmtarget->is_method()) {
2411 Method* m = (Method*)vmtarget;
2412 oop appendix = appendix_box->obj_at(0);
2413 if (TraceMethodHandles) {
2414 #ifndef PRODUCT
2415 tty->print("Linked method="INTPTR_FORMAT": ", m);
2416 m->print();
2417 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2418 tty->cr();
2419 #endif //PRODUCT
2420 }
2421 (*appendix_result) = Handle(THREAD, appendix);
2422 return methodHandle(THREAD, m);
2423 }
2424 }
2425 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2426 return empty;
2427 }
2428
2429 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2430 Symbol* signature,
2431 KlassHandle accessing_klass,
2432 Handle *appendix_result,
2433 Handle *method_type_result,
2434 TRAPS) {
2435 methodHandle empty;
2436 assert(EnableInvokeDynamic, "");
2437 assert(!THREAD->is_Compiler_thread(), "");
2438 Handle method_type =
2439 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2440 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2441 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2442 }
2443
2444 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2445 int ref_kind = JVM_REF_invokeVirtual;
2446 Handle name_str = StringTable::intern(name, CHECK_(empty));
2447 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2448 assert(appendix_box->obj_at(0) == NULL, "");
2449
2450 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2451 JavaCallArguments args;
2452 args.push_oop(accessing_klass()->java_mirror());
2453 args.push_int(ref_kind);
2454 args.push_oop(mh_klass()->java_mirror());
2455 args.push_oop(name_str());
2456 args.push_oop(method_type());
2457 args.push_oop(appendix_box());
2458 JavaValue result(T_OBJECT);
2459 JavaCalls::call_static(&result,
2460 SystemDictionary::MethodHandleNatives_klass(),
2461 vmSymbols::linkMethod_name(),
2462 vmSymbols::linkMethod_signature(),
2463 &args, CHECK_(empty));
2464 Handle mname(THREAD, (oop) result.get_jobject());
2465 (*method_type_result) = method_type;
2466 return unpack_method_and_appendix(mname, appendix_box, appendix_result, THREAD);
2467 }
2468
2469
2470 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2471 // signature, as interpreted relative to the given class loader.
2472 // Because of class loader constraints, all method handle usage must be
2473 // consistent with this loader.
2474 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2475 KlassHandle accessing_klass,
2476 TRAPS) {
2477 Handle empty;
2478 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2479 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2480 int index = invoke_method_table()->hash_to_index(hash);
2481 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2482 if (spe != NULL && spe->method_type() != NULL) {
2483 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2484 return Handle(THREAD, spe->method_type());
2485 } else if (THREAD->is_Compiler_thread()) {
2486 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2487 return Handle(); // do not attempt from within compiler, unless it was cached
2488 }
2489
2490 Handle class_loader, protection_domain;
2491 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2492 int npts = ArgumentCount(signature).size();
2493 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2494 int arg = 0;
2495 Handle rt; // the return type from the signature
2496 ResourceMark rm(THREAD);
2497 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2498 oop mirror = NULL;
2499 if (is_on_bcp) {
2500 // Note: class_loader & protection_domain are both null at this point.
2501 mirror = ss.as_java_mirror(class_loader, protection_domain,
2502 SignatureStream::ReturnNull, CHECK_(empty));
2503 if (mirror == NULL) {
2504 // fall back from BCP to accessing_klass
2505 if (accessing_klass.not_null()) {
2506 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2507 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2508 }
2509 is_on_bcp = false;
2510 }
2511 }
2512 if (!is_on_bcp) {
2513 // Resolve, throwing a real error if it doesn't work.
2514 mirror = ss.as_java_mirror(class_loader, protection_domain,
2515 SignatureStream::NCDFError, CHECK_(empty));
2516 }
2517 if (ss.at_return_type())
2518 rt = Handle(THREAD, mirror);
2519 else
2520 pts->obj_at_put(arg++, mirror);
2521
2522 // Check accessibility.
2523 if (ss.is_object() && accessing_klass.not_null()) {
2524 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2525 mirror = NULL; // safety
2526 // Emulate ConstantPool::verify_constant_pool_resolve.
2527 if (Klass::cast(sel_klass)->oop_is_objArray())
2528 sel_klass = objArrayKlass::cast(sel_klass)->bottom_klass();
2529 if (Klass::cast(sel_klass)->oop_is_instance()) {
2530 KlassHandle sel_kh(THREAD, sel_klass);
2531 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2532 }
2533 }
2534 }
2535 assert(arg == npts, "");
2536
2537 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2538 JavaCallArguments args(Handle(THREAD, rt()));
2539 args.push_oop(pts());
2540 JavaValue result(T_OBJECT);
2541 JavaCalls::call_static(&result,
2542 SystemDictionary::MethodHandleNatives_klass(),
2543 vmSymbols::findMethodHandleType_name(),
2544 vmSymbols::findMethodHandleType_signature(),
2545 &args, CHECK_(empty));
2546 Handle method_type(THREAD, (oop) result.get_jobject());
2547
2548 if (is_on_bcp) {
2549 // We can cache this MethodType inside the JVM.
2550 MutexLocker ml(SystemDictionary_lock, THREAD);
2551 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2552 if (spe == NULL)
2553 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2554 if (spe->method_type() == NULL) {
2555 spe->set_method_type(method_type());
2556 }
2557 }
2558
2559 // report back to the caller with the MethodType
2560 return method_type;
2561 }
2562
2563 // Ask Java code to find or construct a method handle constant.
2564 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2565 int ref_kind, //e.g., JVM_REF_invokeVirtual
2566 KlassHandle callee,
2567 Symbol* name_sym,
2568 Symbol* signature,
2569 TRAPS) {
2570 Handle empty;
2571 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2572 Handle type;
2573 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2574 type = find_method_handle_type(signature, caller, CHECK_(empty));
2575 } else {
2576 ResourceMark rm(THREAD);
2577 SignatureStream ss(signature, false);
2578 if (!ss.is_done()) {
2579 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2580 SignatureStream::NCDFError, CHECK_(empty));
2581 type = Handle(THREAD, mirror);
2582 ss.next();
2583 if (!ss.is_done()) type = Handle(); // error!
2584 }
2585 }
2586 if (type.is_null()) {
2587 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2588 }
2589
2590 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2591 JavaCallArguments args;
2592 args.push_oop(caller->java_mirror()); // the referring class
2593 args.push_int(ref_kind);
2594 args.push_oop(callee->java_mirror()); // the target class
2595 args.push_oop(name());
2596 args.push_oop(type());
2597 JavaValue result(T_OBJECT);
2598 JavaCalls::call_static(&result,
2599 SystemDictionary::MethodHandleNatives_klass(),
2600 vmSymbols::linkMethodHandleConstant_name(),
2601 vmSymbols::linkMethodHandleConstant_signature(),
2602 &args, CHECK_(empty));
2603 return Handle(THREAD, (oop) result.get_jobject());
2604 }
2605
2606 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2607 // name and signature, as interpreted relative to the given class loader.
2608 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2609 Handle bootstrap_specifier,
2610 Symbol* name,
2611 Symbol* type,
2612 Handle *appendix_result,
2613 Handle *method_type_result,
2614 TRAPS) {
2615 methodHandle empty;
2616 Handle bsm, info;
2617 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2618 bsm = bootstrap_specifier;
2619 } else {
2620 assert(bootstrap_specifier->is_objArray(), "");
2621 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2622 int len = args->length();
2623 assert(len >= 1, "");
2624 bsm = Handle(THREAD, args->obj_at(0));
2625 if (len > 1) {
2626 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2627 for (int i = 1; i < len; i++)
2628 args1->obj_at_put(i-1, args->obj_at(i));
2629 info = Handle(THREAD, args1);
2630 }
2631 }
2632 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2633 "caller must supply a valid BSM");
2634
2635 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2636 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2637
2638 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2639 assert(appendix_box->obj_at(0) == NULL, "");
2640
2641 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2642 JavaCallArguments args;
2643 args.push_oop(caller->java_mirror());
2644 args.push_oop(bsm());
2645 args.push_oop(method_name());
2646 args.push_oop(method_type());
2647 args.push_oop(info());
2648 args.push_oop(appendix_box);
2649 JavaValue result(T_OBJECT);
2650 JavaCalls::call_static(&result,
2651 SystemDictionary::MethodHandleNatives_klass(),
2652 vmSymbols::linkCallSite_name(),
2653 vmSymbols::linkCallSite_signature(),
2654 &args, CHECK_(empty));
2655 Handle mname(THREAD, (oop) result.get_jobject());
2656 (*method_type_result) = method_type;
2657 return unpack_method_and_appendix(mname, appendix_box, appendix_result, THREAD);
2658 }
2659
2660 // Since the identity hash code for symbols changes when the symbols are
2661 // moved from the regular perm gen (hash in the mark word) to the shared
2662 // spaces (hash is the address), the classes loaded into the dictionary
2663 // may be in the wrong buckets.
2664
2665 void SystemDictionary::reorder_dictionary() {
2666 dictionary()->reorder_dictionary();
2667 }
2668
2669
2670 void SystemDictionary::copy_buckets(char** top, char* end) {
2671 dictionary()->copy_buckets(top, end);
2672 }
2673
2674
2675 void SystemDictionary::copy_table(char** top, char* end) {
2676 dictionary()->copy_table(top, end);
2677 }
2678
2679
2680 void SystemDictionary::reverse() {
2681 dictionary()->reverse();
2682 }
2683
2684 int SystemDictionary::number_of_classes() {
2685 return dictionary()->number_of_entries();
2686 }
2687
2688
2689 // ----------------------------------------------------------------------------
2690 #ifndef PRODUCT
2691
2692 void SystemDictionary::print() {
2693 dictionary()->print();
2694
2695 // Placeholders
2696 GCMutexLocker mu(SystemDictionary_lock);
2697 placeholders()->print();
2698
2699 // loader constraints - print under SD_lock
2700 constraints()->print();
2701 }
2702
2703 #endif
2704
2705 void SystemDictionary::verify() {
2706 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2707 guarantee(constraints() != NULL,
2708 "Verify of loader constraints failed");
2709 guarantee(dictionary()->number_of_entries() >= 0 &&
2710 placeholders()->number_of_entries() >= 0,
2711 "Verify of system dictionary failed");
2712
2713 // Verify dictionary
2714 dictionary()->verify();
2715
2716 GCMutexLocker mu(SystemDictionary_lock);
2717 placeholders()->verify();
2718
2719 // Verify constraint table
2720 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2721 constraints()->verify(dictionary(), placeholders());
2722 }
2723
2724
2725 void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
2726 ClassLoaderData* loader_data) {
2727 GCMutexLocker mu(SystemDictionary_lock);
2728 Symbol* name;
2729
2730 Klass* probe = find_class(class_name, loader_data);
2731 if (probe == NULL) {
2732 probe = SystemDictionary::find_shared_class(class_name);
2733 if (probe == NULL) {
2734 name = find_placeholder(class_name, loader_data);
2735 }
2736 }
2737 guarantee(probe != NULL || name != NULL,
2738 "Loaded klasses should be in SystemDictionary");
2739 }
2740
2741 #ifndef PRODUCT
2742
2743 // statistics code
2744 class ClassStatistics: AllStatic {
2745 private:
2746 static int nclasses; // number of classes
2747 static int nmethods; // number of methods
2748 static int nmethoddata; // number of methodData
2749 static int class_size; // size of class objects in words
2750 static int method_size; // size of method objects in words
2751 static int debug_size; // size of debug info in methods
2752 static int methoddata_size; // size of methodData objects in words
2753
2754 static void do_class(Klass* k) {
2755 nclasses++;
2756 class_size += k->size();
2757 if (k->oop_is_instance()) {
2758 InstanceKlass* ik = (InstanceKlass*)k;
2759 class_size += ik->methods()->size();
2760 class_size += ik->constants()->size();
2761 class_size += ik->local_interfaces()->size();
2762 class_size += ik->transitive_interfaces()->size();
2763 // We do not have to count implementors, since we only store one!
2764 // SSS: How should these be accounted now that they have moved?
2765 // class_size += ik->fields()->length();
2766 }
2767 }
2768
2769 static void do_method(Method* m) {
2770 nmethods++;
2771 method_size += m->size();
2772 // class loader uses same objArray for empty vectors, so don't count these
2773 if (m->has_stackmap_table()) {
2774 method_size += m->stackmap_data()->size();
2775 }
2776
2777 MethodData* mdo = m->method_data();
2778 if (mdo != NULL) {
2779 nmethoddata++;
2780 methoddata_size += mdo->size();
2781 }
2782 }
2783
2784 public:
2785 static void print() {
2786 SystemDictionary::classes_do(do_class);
2787 SystemDictionary::methods_do(do_method);
2788 tty->print_cr("Class statistics:");
2789 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2790 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2791 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2792 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2793 }
2794 };
2795
2796
2797 int ClassStatistics::nclasses = 0;
2798 int ClassStatistics::nmethods = 0;
2799 int ClassStatistics::nmethoddata = 0;
2800 int ClassStatistics::class_size = 0;
2801 int ClassStatistics::method_size = 0;
2802 int ClassStatistics::debug_size = 0;
2803 int ClassStatistics::methoddata_size = 0;
2804
2805 void SystemDictionary::print_class_statistics() {
2806 ResourceMark rm;
2807 ClassStatistics::print();
2808 }
2809
2810
2811 class MethodStatistics: AllStatic {
2812 public:
2813 enum {
2814 max_parameter_size = 10
2815 };
2816 private:
2817
2818 static int _number_of_methods;
2819 static int _number_of_final_methods;
2820 static int _number_of_static_methods;
2821 static int _number_of_native_methods;
2822 static int _number_of_synchronized_methods;
2823 static int _number_of_profiled_methods;
2824 static int _number_of_bytecodes;
2825 static int _parameter_size_profile[max_parameter_size];
2826 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2827
2828 static void initialize() {
2829 _number_of_methods = 0;
2830 _number_of_final_methods = 0;
2831 _number_of_static_methods = 0;
2832 _number_of_native_methods = 0;
2833 _number_of_synchronized_methods = 0;
2834 _number_of_profiled_methods = 0;
2835 _number_of_bytecodes = 0;
2836 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2837 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2838 };
2839
2840 static void do_method(Method* m) {
2841 _number_of_methods++;
2842 // collect flag info
2843 if (m->is_final() ) _number_of_final_methods++;
2844 if (m->is_static() ) _number_of_static_methods++;
2845 if (m->is_native() ) _number_of_native_methods++;
2846 if (m->is_synchronized()) _number_of_synchronized_methods++;
2847 if (m->method_data() != NULL) _number_of_profiled_methods++;
2848 // collect parameter size info (add one for receiver, if any)
2849 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2850 // collect bytecodes info
2851 {
2852 Thread *thread = Thread::current();
2853 HandleMark hm(thread);
2854 BytecodeStream s(methodHandle(thread, m));
2855 Bytecodes::Code c;
2856 while ((c = s.next()) >= 0) {
2857 _number_of_bytecodes++;
2858 _bytecodes_profile[c]++;
2859 }
2860 }
2861 }
2862
2863 public:
2864 static void print() {
2865 initialize();
2866 SystemDictionary::methods_do(do_method);
2867 // generate output
2868 tty->cr();
2869 tty->print_cr("Method statistics (static):");
2870 // flag distribution
2871 tty->cr();
2872 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2873 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2874 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2875 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2876 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2877 // parameter size profile
2878 tty->cr();
2879 { int tot = 0;
2880 int avg = 0;
2881 for (int i = 0; i < max_parameter_size; i++) {
2882 int n = _parameter_size_profile[i];
2883 tot += n;
2884 avg += n*i;
2885 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2886 }
2887 assert(tot == _number_of_methods, "should be the same");
2888 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2889 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2890 }
2891 // bytecodes profile
2892 tty->cr();
2893 { int tot = 0;
2894 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2895 if (Bytecodes::is_defined(i)) {
2896 Bytecodes::Code c = Bytecodes::cast(i);
2897 int n = _bytecodes_profile[c];
2898 tot += n;
2899 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2900 }
2901 }
2902 assert(tot == _number_of_bytecodes, "should be the same");
2903 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2904 }
2905 tty->cr();
2906 }
2907 };
2908
2909 int MethodStatistics::_number_of_methods;
2910 int MethodStatistics::_number_of_final_methods;
2911 int MethodStatistics::_number_of_static_methods;
2912 int MethodStatistics::_number_of_native_methods;
2913 int MethodStatistics::_number_of_synchronized_methods;
2914 int MethodStatistics::_number_of_profiled_methods;
2915 int MethodStatistics::_number_of_bytecodes;
2916 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2917 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2918
2919
2920 void SystemDictionary::print_method_statistics() {
2921 MethodStatistics::print();
2922 }
2923
2924 #endif // PRODUCT