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