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