1 /*
2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/dictionary.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/loaderConstraints.hpp"
29 #include "classfile/placeholders.hpp"
30 #include "classfile/resolutionErrors.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "interpreter/bytecodeStream.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "memory/gcLocker.hpp"
36 #include "memory/oopFactory.hpp"
37 #include "oops/instanceKlass.hpp"
38 #include "oops/instanceRefKlass.hpp"
39 #include "oops/klass.inline.hpp"
40 #include "oops/methodDataOop.hpp"
41 #include "oops/objArrayKlass.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/oop.inline2.hpp"
44 #include "oops/typeArrayKlass.hpp"
45 #include "prims/jvmtiEnvBase.hpp"
46 #include "prims/methodHandles.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/fieldType.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/java.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "runtime/signature.hpp"
54 #include "services/classLoadingService.hpp"
55 #include "services/threadService.hpp"
56
57
58 Dictionary* SystemDictionary::_dictionary = NULL;
59 PlaceholderTable* SystemDictionary::_placeholders = NULL;
60 Dictionary* SystemDictionary::_shared_dictionary = NULL;
61 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
62 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
63 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
64
65
66 int SystemDictionary::_number_of_modifications = 0;
67 int SystemDictionary::_sdgeneration = 0;
68 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
69 20201,40423,99991};
70
71 oop SystemDictionary::_system_loader_lock_obj = NULL;
72
73 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
74 = { NULL /*, NULL...*/ };
75
76 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
77
78 oop SystemDictionary::_java_system_loader = NULL;
79
80 bool SystemDictionary::_has_loadClassInternal = false;
81 bool SystemDictionary::_has_checkPackageAccess = false;
82
83 // lazily initialized klass variables
84 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
85
86
87 // ----------------------------------------------------------------------------
88 // Java-level SystemLoader
89
90 oop SystemDictionary::java_system_loader() {
91 return _java_system_loader;
92 }
93
94 void SystemDictionary::compute_java_system_loader(TRAPS) {
95 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
96 JavaValue result(T_OBJECT);
97 JavaCalls::call_static(&result,
98 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
99 vmSymbols::getSystemClassLoader_name(),
100 vmSymbols::void_classloader_signature(),
101 CHECK);
102
103 _java_system_loader = (oop)result.get_jobject();
104 }
105
106
107 // ----------------------------------------------------------------------------
108 // debugging
109
110 #ifdef ASSERT
111
112 // return true if class_name contains no '.' (internal format is '/')
113 bool SystemDictionary::is_internal_format(Symbol* class_name) {
114 if (class_name != NULL) {
115 ResourceMark rm;
116 char* name = class_name->as_C_string();
117 return strchr(name, '.') == NULL;
118 } else {
119 return true;
120 }
121 }
122
123 #endif
124
125 // ----------------------------------------------------------------------------
126 // Parallel class loading check
127
128 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
129 if (UnsyncloadClass || class_loader.is_null()) return true;
130 if (AlwaysLockClassLoader) return false;
131 return java_lang_ClassLoader::parallelCapable(class_loader());
132 }
133 // ----------------------------------------------------------------------------
134 // ParallelDefineClass flag does not apply to bootclass loader
135 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
136 if (class_loader.is_null()) return false;
137 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
138 return true;
139 }
140 return false;
141 }
142 // ----------------------------------------------------------------------------
143 // Resolving of classes
144
145 // Forwards to resolve_or_null
146
147 klassOop SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
148 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
149 if (HAS_PENDING_EXCEPTION || klass == NULL) {
150 KlassHandle k_h(THREAD, klass);
151 // can return a null klass
152 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
153 }
154 return klass;
155 }
156
157 klassOop SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
158 if (HAS_PENDING_EXCEPTION) {
159 // If we have a pending exception we forward it to the caller, unless throw_error is true,
160 // in which case we have to check whether the pending exception is a ClassNotFoundException,
161 // and if so convert it to a NoClassDefFoundError
162 // And chain the original ClassNotFoundException
163 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
164 ResourceMark rm(THREAD);
165 assert(klass_h() == NULL, "Should not have result with exception pending");
166 Handle e(THREAD, PENDING_EXCEPTION);
167 CLEAR_PENDING_EXCEPTION;
168 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
169 } else {
170 return NULL;
171 }
172 }
173 // Class not found, throw appropriate error or exception depending on value of throw_error
174 if (klass_h() == NULL) {
175 ResourceMark rm(THREAD);
176 if (throw_error) {
177 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
178 } else {
179 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
180 }
181 }
182 return (klassOop)klass_h();
183 }
184
185
186 klassOop SystemDictionary::resolve_or_fail(Symbol* class_name,
187 bool throw_error, TRAPS)
188 {
189 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
190 }
191
192
193 // Forwards to resolve_instance_class_or_null
194
195 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
196 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
197 if (FieldType::is_array(class_name)) {
198 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
199 } else if (FieldType::is_obj(class_name)) {
200 ResourceMark rm(THREAD);
201 // Ignore wrapping L and ;.
202 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
203 class_name->utf8_length() - 2, CHECK_NULL);
204 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
205 } else {
206 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
207 }
208 }
209
210 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
211 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
212 }
213
214 // Forwards to resolve_instance_class_or_null
215
216 klassOop SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
217 Handle class_loader,
218 Handle protection_domain,
219 TRAPS) {
220 assert(FieldType::is_array(class_name), "must be array");
221 klassOop k = NULL;
222 FieldArrayInfo fd;
223 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
224 // of this call
225 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
226 if (t == T_OBJECT) {
227 // naked oop "k" is OK here -- we assign back into it
228 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
229 class_loader,
230 protection_domain,
231 CHECK_NULL);
232 if (k != NULL) {
233 k = Klass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
234 }
235 } else {
236 k = Universe::typeArrayKlassObj(t);
237 k = typeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
238 }
239 return k;
240 }
241
242
243 // Must be called for any super-class or super-interface resolution
244 // during class definition to allow class circularity checking
245 // super-interface callers:
246 // parse_interfaces - for defineClass & jvmtiRedefineClasses
247 // super-class callers:
248 // ClassFileParser - for defineClass & jvmtiRedefineClasses
249 // load_shared_class - while loading a class from shared archive
250 // resolve_instance_class_or_null:
251 // via: handle_parallel_super_load
252 // when resolving a class that has an existing placeholder with
253 // a saved superclass [i.e. a defineClass is currently in progress]
254 // if another thread is trying to resolve the class, it must do
255 // super-class checks on its own thread to catch class circularity
256 // This last call is critical in class circularity checking for cases
257 // where classloading is delegated to different threads and the
258 // classloader lock is released.
259 // Take the case: Base->Super->Base
260 // 1. If thread T1 tries to do a defineClass of class Base
261 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
262 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
263 // so it tries to load Super
264 // 3. If we load the class internally, or user classloader uses same thread
265 // loadClassFromxxx or defineClass via parseClassFile Super ...
266 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
267 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
268 // 3.4 calls resolve_super_or_fail Base
269 // 3.5 finds T1,Base -> throws class circularity
270 //OR 4. If T2 tries to resolve Super via defineClass Super ...
271 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
272 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
273 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
274 // 4.4 finds T2, Super -> throws class circularity
275 // Must be called, even if superclass is null, since this is
276 // where the placeholder entry is created which claims this
277 // thread is loading this class/classloader.
278 klassOop SystemDictionary::resolve_super_or_fail(Symbol* child_name,
279 Symbol* class_name,
280 Handle class_loader,
281 Handle protection_domain,
282 bool is_superclass,
283 TRAPS) {
284
285 // Try to get one of the well-known klasses.
286 // They are trusted, and do not participate in circularities.
287 if (LinkWellKnownClasses) {
288 klassOop k = find_well_known_klass(class_name);
289 if (k != NULL) {
290 return k;
291 }
292 }
293
294 // Double-check, if child class is already loaded, just return super-class,interface
295 // Don't add a placedholder if already loaded, i.e. already in system dictionary
296 // Make sure there's a placeholder for the *child* before resolving.
297 // Used as a claim that this thread is currently loading superclass/classloader
298 // Used here for ClassCircularity checks and also for heap verification
299 // (every instanceKlass in the heap needs to be in the system dictionary
300 // or have a placeholder).
301 // Must check ClassCircularity before checking if super class is already loaded
302 //
303 // We might not already have a placeholder if this child_name was
304 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
305 // the name of the class might not be known until the stream is actually
306 // parsed.
307 // Bugs 4643874, 4715493
308 // compute_hash can have a safepoint
309
310 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
311 int d_index = dictionary()->hash_to_index(d_hash);
312 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
313 int p_index = placeholders()->hash_to_index(p_hash);
314 // can't throw error holding a lock
315 bool child_already_loaded = false;
316 bool throw_circularity_error = false;
317 {
318 MutexLocker mu(SystemDictionary_lock, THREAD);
319 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
320 klassOop quicksuperk;
321 // to support // loading: if child done loading, just return superclass
322 // if class_name, & class_loader don't match:
323 // if initial define, SD update will give LinkageError
324 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
325 // so we don't throw an exception here.
326 // see: nsk redefclass014 & java.lang.instrument Instrument032
327 if ((childk != NULL ) && (is_superclass) &&
328 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
329
330 ((Klass::cast(quicksuperk)->name() == class_name) &&
331 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
332 return quicksuperk;
333 } else {
334 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
335 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
336 throw_circularity_error = true;
337 }
338 }
339 if (!throw_circularity_error) {
340 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
341 }
342 }
343 if (throw_circularity_error) {
344 ResourceMark rm(THREAD);
345 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
346 }
347
348 // java.lang.Object should have been found above
349 assert(class_name != NULL, "null super class for resolving");
350 // Resolve the super class or interface, check results on return
351 klassOop superk = NULL;
352 superk = SystemDictionary::resolve_or_null(class_name,
353 class_loader,
354 protection_domain,
355 THREAD);
356
357 KlassHandle superk_h(THREAD, superk);
358
359 // Note: clean up of placeholders currently in callers of
360 // resolve_super_or_fail - either at update_dictionary time
361 // or on error
362 {
363 MutexLocker mu(SystemDictionary_lock, THREAD);
364 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
365 if (probe != NULL) {
366 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
367 }
368 }
369 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
370 // can null superk
371 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
372 }
373
374 return superk_h();
375 }
376
377 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
378 Handle class_loader,
379 Handle protection_domain,
380 TRAPS) {
381 if(!has_checkPackageAccess()) return;
382
383 // Now we have to call back to java to check if the initating class has access
384 JavaValue result(T_VOID);
385 if (TraceProtectionDomainVerification) {
386 // Print out trace information
387 tty->print_cr("Checking package access");
388 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
389 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
390 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
391 }
392
393 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
394
395 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
396 JavaCalls::call_special(&result,
397 class_loader,
398 system_loader,
399 vmSymbols::checkPackageAccess_name(),
400 vmSymbols::class_protectiondomain_signature(),
401 Handle(THREAD, klass->java_mirror()),
402 protection_domain,
403 THREAD);
404
405 if (TraceProtectionDomainVerification) {
406 if (HAS_PENDING_EXCEPTION) {
407 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
408 } else {
409 tty->print_cr(" -> granted");
410 }
411 tty->cr();
412 }
413
414 if (HAS_PENDING_EXCEPTION) return;
415
416 // If no exception has been thrown, we have validated the protection domain
417 // Insert the protection domain of the initiating class into the set.
418 {
419 // We recalculate the entry here -- we've called out to java since
420 // the last time it was calculated.
421 Symbol* kn = klass->name();
422 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
423 int d_index = dictionary()->hash_to_index(d_hash);
424
425 MutexLocker mu(SystemDictionary_lock, THREAD);
426 {
427 // Note that we have an entry, and entries can be deleted only during GC,
428 // so we cannot allow GC to occur while we're holding this entry.
429
430 // We're using a No_Safepoint_Verifier to catch any place where we
431 // might potentially do a GC at all.
432 // SystemDictionary::do_unloading() asserts that classes are only
433 // unloaded at a safepoint.
434 No_Safepoint_Verifier nosafepoint;
435 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
436 protection_domain, THREAD);
437 }
438 }
439 }
440
441 // We only get here if this thread finds that another thread
442 // has already claimed the placeholder token for the current operation,
443 // but that other thread either never owned or gave up the
444 // object lock
445 // Waits on SystemDictionary_lock to indicate placeholder table updated
446 // On return, caller must recheck placeholder table state
447 //
448 // We only get here if
449 // 1) custom classLoader, i.e. not bootstrap classloader
450 // 2) UnsyncloadClass not set
451 // 3) custom classLoader has broken the class loader objectLock
452 // so another thread got here in parallel
453 //
454 // lockObject must be held.
455 // Complicated dance due to lock ordering:
456 // Must first release the classloader object lock to
457 // allow initial definer to complete the class definition
458 // and to avoid deadlock
459 // Reclaim classloader lock object with same original recursion count
460 // Must release SystemDictionary_lock after notify, since
461 // class loader lock must be claimed before SystemDictionary_lock
462 // to prevent deadlocks
463 //
464 // The notify allows applications that did an untimed wait() on
465 // the classloader object lock to not hang.
466 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
467 assert_lock_strong(SystemDictionary_lock);
468
469 bool calledholdinglock
470 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
471 assert(calledholdinglock,"must hold lock for notify");
472 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
473 ObjectSynchronizer::notifyall(lockObject, THREAD);
474 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
475 SystemDictionary_lock->wait();
476 SystemDictionary_lock->unlock();
477 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
478 SystemDictionary_lock->lock();
479 }
480
481 // If the class in is in the placeholder table, class loading is in progress
482 // For cases where the application changes threads to load classes, it
483 // is critical to ClassCircularity detection that we try loading
484 // the superclass on the same thread internally, so we do parallel
485 // super class loading here.
486 // This also is critical in cases where the original thread gets stalled
487 // even in non-circularity situations.
488 // Note: only one thread can define the class, but multiple can resolve
489 // Note: must call resolve_super_or_fail even if null super -
490 // to force placeholder entry creation for this class for circularity detection
491 // Caller must check for pending exception
492 // Returns non-null klassOop if other thread has completed load
493 // and we are done,
494 // If return null klassOop and no pending exception, the caller must load the class
495 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
496 Symbol* name, Symbol* superclassname, Handle class_loader,
497 Handle protection_domain, Handle lockObject, TRAPS) {
498
499 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
500 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
501 int d_index = dictionary()->hash_to_index(d_hash);
502 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
503 int p_index = placeholders()->hash_to_index(p_hash);
504
505 // superk is not used, resolve_super called for circularity check only
506 // This code is reached in two situations. One if this thread
507 // is loading the same class twice (e.g. ClassCircularity, or
508 // java.lang.instrument).
509 // The second is if another thread started the resolve_super first
510 // and has not yet finished.
511 // In both cases the original caller will clean up the placeholder
512 // entry on error.
513 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
514 superclassname,
515 class_loader,
516 protection_domain,
517 true,
518 CHECK_(nh));
519 // We don't redefine the class, so we just need to clean up if there
520 // was not an error (don't want to modify any system dictionary
521 // data structures).
522 {
523 MutexLocker mu(SystemDictionary_lock, THREAD);
524 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
525 SystemDictionary_lock->notify_all();
526 }
527
528 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
529 // Serial class loaders and bootstrap classloader do wait for superclass loads
530 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
531 MutexLocker mu(SystemDictionary_lock, THREAD);
532 // Check if classloading completed while we were loading superclass or waiting
533 klassOop check = find_class(d_index, d_hash, name, class_loader);
534 if (check != NULL) {
535 // Klass is already loaded, so just return it
536 return(instanceKlassHandle(THREAD, check));
537 } else {
538 return nh;
539 }
540 }
541
542 // must loop to both handle other placeholder updates
543 // and spurious notifications
544 bool super_load_in_progress = true;
545 PlaceholderEntry* placeholder;
546 while (super_load_in_progress) {
547 MutexLocker mu(SystemDictionary_lock, THREAD);
548 // Check if classloading completed while we were loading superclass or waiting
549 klassOop check = find_class(d_index, d_hash, name, class_loader);
550 if (check != NULL) {
551 // Klass is already loaded, so just return it
552 return(instanceKlassHandle(THREAD, check));
553 } else {
554 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
555 if (placeholder && placeholder->super_load_in_progress() ){
556 // Before UnsyncloadClass:
557 // We only get here if the application has released the
558 // classloader lock when another thread was in the middle of loading a
559 // superclass/superinterface for this class, and now
560 // this thread is also trying to load this class.
561 // To minimize surprises, the first thread that started to
562 // load a class should be the one to complete the loading
563 // with the classfile it initially expected.
564 // This logic has the current thread wait once it has done
565 // all the superclass/superinterface loading it can, until
566 // the original thread completes the class loading or fails
567 // If it completes we will use the resulting instanceKlass
568 // which we will find below in the systemDictionary.
569 // We also get here for parallel bootstrap classloader
570 if (class_loader.is_null()) {
571 SystemDictionary_lock->wait();
572 } else {
573 double_lock_wait(lockObject, THREAD);
574 }
575 } else {
576 // If not in SD and not in PH, other thread's load must have failed
577 super_load_in_progress = false;
578 }
579 }
580 }
581 return (nh);
582 }
583
584
585 klassOop SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
586 assert(name != NULL && !FieldType::is_array(name) &&
587 !FieldType::is_obj(name), "invalid class name");
588
589 // UseNewReflection
590 // Fix for 4474172; see evaluation for more details
591 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
592
593 // Do lookup to see if class already exist and the protection domain
594 // has the right access
595 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
596 int d_index = dictionary()->hash_to_index(d_hash);
597 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
598 protection_domain, THREAD);
599 if (probe != NULL) return probe;
600
601
602 // Non-bootstrap class loaders will call out to class loader and
603 // define via jvm/jni_DefineClass which will acquire the
604 // class loader object lock to protect against multiple threads
605 // defining the class in parallel by accident.
606 // This lock must be acquired here so the waiter will find
607 // any successful result in the SystemDictionary and not attempt
608 // the define
609 // ParallelCapable Classloaders and the bootstrap classloader,
610 // or all classloaders with UnsyncloadClass do not acquire lock here
611 bool DoObjectLock = true;
612 if (is_parallelCapable(class_loader)) {
613 DoObjectLock = false;
614 }
615
616 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
617 int p_index = placeholders()->hash_to_index(p_hash);
618
619 // Class is not in SystemDictionary so we have to do loading.
620 // Make sure we are synchronized on the class loader before we proceed
621 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
622 check_loader_lock_contention(lockObject, THREAD);
623 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
624
625 // Check again (after locking) if class already exist in SystemDictionary
626 bool class_has_been_loaded = false;
627 bool super_load_in_progress = false;
628 bool havesupername = false;
629 instanceKlassHandle k;
630 PlaceholderEntry* placeholder;
631 Symbol* superclassname = NULL;
632
633 {
634 MutexLocker mu(SystemDictionary_lock, THREAD);
635 klassOop check = find_class(d_index, d_hash, name, class_loader);
636 if (check != NULL) {
637 // Klass is already loaded, so just return it
638 class_has_been_loaded = true;
639 k = instanceKlassHandle(THREAD, check);
640 } else {
641 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
642 if (placeholder && placeholder->super_load_in_progress()) {
643 super_load_in_progress = true;
644 if (placeholder->havesupername() == true) {
645 superclassname = placeholder->supername();
646 havesupername = true;
647 }
648 }
649 }
650 }
651
652 // If the class in is in the placeholder table, class loading is in progress
653 if (super_load_in_progress && havesupername==true) {
654 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
655 class_loader, protection_domain, lockObject, THREAD);
656 if (HAS_PENDING_EXCEPTION) {
657 return NULL;
658 }
659 if (!k.is_null()) {
660 class_has_been_loaded = true;
661 }
662 }
663
664 if (!class_has_been_loaded) {
665
666 // add placeholder entry to record loading instance class
667 // Five cases:
668 // All cases need to prevent modifying bootclasssearchpath
669 // in parallel with a classload of same classname
670 // Redefineclasses uses existence of the placeholder for the duration
671 // of the class load to prevent concurrent redefinition of not completely
672 // defined classes.
673 // case 1. traditional classloaders that rely on the classloader object lock
674 // - no other need for LOAD_INSTANCE
675 // case 2. traditional classloaders that break the classloader object lock
676 // as a deadlock workaround. Detection of this case requires that
677 // this check is done while holding the classloader object lock,
678 // and that lock is still held when calling classloader's loadClass.
679 // For these classloaders, we ensure that the first requestor
680 // completes the load and other requestors wait for completion.
681 // case 3. UnsyncloadClass - don't use objectLocker
682 // With this flag, we allow parallel classloading of a
683 // class/classloader pair
684 // case4. Bootstrap classloader - don't own objectLocker
685 // This classloader supports parallelism at the classloader level,
686 // but only allows a single load of a class/classloader pair.
687 // No performance benefit and no deadlock issues.
688 // case 5. parallelCapable user level classloaders - without objectLocker
689 // Allow parallel classloading of a class/classloader pair
690 bool throw_circularity_error = false;
691 {
692 MutexLocker mu(SystemDictionary_lock, THREAD);
693 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
694 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
695 if (oldprobe) {
696 // only need check_seen_thread once, not on each loop
697 // 6341374 java/lang/Instrument with -Xcomp
698 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
699 throw_circularity_error = true;
700 } else {
701 // case 1: traditional: should never see load_in_progress.
702 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
703
704 // case 4: bootstrap classloader: prevent futile classloading,
705 // wait on first requestor
706 if (class_loader.is_null()) {
707 SystemDictionary_lock->wait();
708 } else {
709 // case 2: traditional with broken classloader lock. wait on first
710 // requestor.
711 double_lock_wait(lockObject, THREAD);
712 }
713 // Check if classloading completed while we were waiting
714 klassOop check = find_class(d_index, d_hash, name, class_loader);
715 if (check != NULL) {
716 // Klass is already loaded, so just return it
717 k = instanceKlassHandle(THREAD, check);
718 class_has_been_loaded = true;
719 }
720 // check if other thread failed to load and cleaned up
721 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
722 }
723 }
724 }
725 }
726 // All cases: add LOAD_INSTANCE
727 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
728 // LOAD_INSTANCE in parallel
729 // add placeholder entry even if error - callers will remove on error
730 if (!throw_circularity_error && !class_has_been_loaded) {
731 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
732 // For class loaders that do not acquire the classloader object lock,
733 // if they did not catch another thread holding LOAD_INSTANCE,
734 // need a check analogous to the acquire ObjectLocker/find_class
735 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
736 // one final check if the load has already completed
737 // class loaders holding the ObjectLock shouldn't find the class here
738 klassOop check = find_class(d_index, d_hash, name, class_loader);
739 if (check != NULL) {
740 // Klass is already loaded, so just return it
741 k = instanceKlassHandle(THREAD, check);
742 class_has_been_loaded = true;
743 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
744 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
745 SystemDictionary_lock->notify_all();
746 }
747 }
748 }
749 // must throw error outside of owning lock
750 if (throw_circularity_error) {
751 ResourceMark rm(THREAD);
752 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
753 }
754
755 if (!class_has_been_loaded) {
756
757 // Do actual loading
758 k = load_instance_class(name, class_loader, THREAD);
759
760 // For UnsyncloadClass only
761 // If they got a linkageError, check if a parallel class load succeeded.
762 // If it did, then for bytecode resolution the specification requires
763 // that we return the same result we did for the other thread, i.e. the
764 // successfully loaded instanceKlass
765 // Should not get here for classloaders that support parallelism
766 // with the new cleaner mechanism, even with AllowParallelDefineClass
767 // Bootstrap goes through here to allow for an extra guarantee check
768 if (UnsyncloadClass || (class_loader.is_null())) {
769 if (k.is_null() && HAS_PENDING_EXCEPTION
770 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
771 MutexLocker mu(SystemDictionary_lock, THREAD);
772 klassOop check = find_class(d_index, d_hash, name, class_loader);
773 if (check != NULL) {
774 // Klass is already loaded, so just use it
775 k = instanceKlassHandle(THREAD, check);
776 CLEAR_PENDING_EXCEPTION;
777 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
778 }
779 }
780 }
781
782 // clean up placeholder entries for success or error
783 // This cleans up LOAD_INSTANCE entries
784 // It also cleans up LOAD_SUPER entries on errors from
785 // calling load_instance_class
786 {
787 MutexLocker mu(SystemDictionary_lock, THREAD);
788 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
789 if (probe != NULL) {
790 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
791 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
792 SystemDictionary_lock->notify_all();
793 }
794 }
795
796 // If everything was OK (no exceptions, no null return value), and
797 // class_loader is NOT the defining loader, do a little more bookkeeping.
798 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
799 k->class_loader() != class_loader()) {
800
801 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
802
803 // Need to check for a PENDING_EXCEPTION again; check_constraints
804 // can throw and doesn't use the CHECK macro.
805 if (!HAS_PENDING_EXCEPTION) {
806 { // Grabbing the Compile_lock prevents systemDictionary updates
807 // during compilations.
808 MutexLocker mu(Compile_lock, THREAD);
809 update_dictionary(d_index, d_hash, p_index, p_hash,
810 k, class_loader, THREAD);
811 }
812 if (JvmtiExport::should_post_class_load()) {
813 Thread *thread = THREAD;
814 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
815 JvmtiExport::post_class_load((JavaThread *) thread, k());
816 }
817 }
818 }
819 if (HAS_PENDING_EXCEPTION || k.is_null()) {
820 // On error, clean up placeholders
821 {
822 MutexLocker mu(SystemDictionary_lock, THREAD);
823 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
824 SystemDictionary_lock->notify_all();
825 }
826 return NULL;
827 }
828 }
829 }
830
831 #ifdef ASSERT
832 {
833 Handle loader (THREAD, k->class_loader());
834 MutexLocker mu(SystemDictionary_lock, THREAD);
835 oop kk = find_class(name, loader);
836 assert(kk == k(), "should be present in dictionary");
837 }
838 #endif
839
840 // return if the protection domain in NULL
841 if (protection_domain() == NULL) return k();
842
843 // Check the protection domain has the right access
844 {
845 MutexLocker mu(SystemDictionary_lock, THREAD);
846 // Note that we have an entry, and entries can be deleted only during GC,
847 // so we cannot allow GC to occur while we're holding this entry.
848 // We're using a No_Safepoint_Verifier to catch any place where we
849 // might potentially do a GC at all.
850 // SystemDictionary::do_unloading() asserts that classes are only
851 // unloaded at a safepoint.
852 No_Safepoint_Verifier nosafepoint;
853 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
854 class_loader,
855 protection_domain)) {
856 return k();
857 }
858 }
859
860 // Verify protection domain. If it fails an exception is thrown
861 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
862
863 return k();
864 }
865
866
867 // This routine does not lock the system dictionary.
868 //
869 // Since readers don't hold a lock, we must make sure that system
870 // dictionary entries are only removed at a safepoint (when only one
871 // thread is running), and are added to in a safe way (all links must
872 // be updated in an MT-safe manner).
873 //
874 // Callers should be aware that an entry could be added just after
875 // _dictionary->bucket(index) is read here, so the caller will not see
876 // the new entry.
877
878 klassOop SystemDictionary::find(Symbol* class_name,
879 Handle class_loader,
880 Handle protection_domain,
881 TRAPS) {
882
883 // UseNewReflection
884 // The result of this call should be consistent with the result
885 // of the call to resolve_instance_class_or_null().
886 // See evaluation 6790209 and 4474172 for more details.
887 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
888
889 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
890 int d_index = dictionary()->hash_to_index(d_hash);
891
892 {
893 // Note that we have an entry, and entries can be deleted only during GC,
894 // so we cannot allow GC to occur while we're holding this entry.
895 // We're using a No_Safepoint_Verifier to catch any place where we
896 // might potentially do a GC at all.
897 // SystemDictionary::do_unloading() asserts that classes are only
898 // unloaded at a safepoint.
899 No_Safepoint_Verifier nosafepoint;
900 return dictionary()->find(d_index, d_hash, class_name, class_loader,
901 protection_domain, THREAD);
902 }
903 }
904
905
906 // Look for a loaded instance or array klass by name. Do not do any loading.
907 // return NULL in case of error.
908 klassOop SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
909 Handle class_loader,
910 Handle protection_domain,
911 TRAPS) {
912 klassOop k = NULL;
913 assert(class_name != NULL, "class name must be non NULL");
914
915 // Try to get one of the well-known klasses.
916 if (LinkWellKnownClasses) {
917 k = find_well_known_klass(class_name);
918 if (k != NULL) {
919 return k;
920 }
921 }
922
923 if (FieldType::is_array(class_name)) {
924 // The name refers to an array. Parse the name.
925 // dimension and object_key in FieldArrayInfo are assigned as a
926 // side-effect of this call
927 FieldArrayInfo fd;
928 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
929 if (t != T_OBJECT) {
930 k = Universe::typeArrayKlassObj(t);
931 } else {
932 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
933 }
934 if (k != NULL) {
935 k = Klass::cast(k)->array_klass_or_null(fd.dimension());
936 }
937 } else {
938 k = find(class_name, class_loader, protection_domain, THREAD);
939 }
940 return k;
941 }
942
943 // Quick range check for names of well-known classes:
944 static Symbol* wk_klass_name_limits[2] = {NULL, NULL};
945
946 #ifndef PRODUCT
947 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
948 // counts for "hello world": 3983, 1616, 1075
949 // => 60% hit after limit guard, 25% total win rate
950 #endif
951
952 klassOop SystemDictionary::find_well_known_klass(Symbol* class_name) {
953 // A bounds-check on class_name will quickly get a negative result.
954 NOT_PRODUCT(find_wkk_calls++);
955 if (class_name >= wk_klass_name_limits[0] &&
956 class_name <= wk_klass_name_limits[1]) {
957 NOT_PRODUCT(find_wkk_probes++);
958 vmSymbols::SID sid = vmSymbols::find_sid(class_name);
959 if (sid != vmSymbols::NO_SID) {
960 klassOop k = NULL;
961 switch (sid) {
962 #define WK_KLASS_CASE(name, symbol, ignore_option) \
963 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
964 k = WK_KLASS(name); break;
965 WK_KLASSES_DO(WK_KLASS_CASE)
966 #undef WK_KLASS_CASE
967 }
968 NOT_PRODUCT(if (k != NULL) find_wkk_wins++);
969 return k;
970 }
971 }
972 return NULL;
973 }
974
975 // Note: this method is much like resolve_from_stream, but
976 // updates no supplemental data structures.
977 // TODO consolidate the two methods with a helper routine?
978 klassOop SystemDictionary::parse_stream(Symbol* class_name,
979 Handle class_loader,
980 Handle protection_domain,
981 ClassFileStream* st,
982 KlassHandle host_klass,
983 GrowableArray<Handle>* cp_patches,
984 TRAPS) {
985 TempNewSymbol parsed_name = NULL;
986
987 // Parse the stream. Note that we do this even though this klass might
988 // already be present in the SystemDictionary, otherwise we would not
989 // throw potential ClassFormatErrors.
990 //
991 // Note: "name" is updated.
992 // Further note: a placeholder will be added for this class when
993 // super classes are loaded (resolve_super_or_fail). We expect this
994 // to be called for all classes but java.lang.Object; and we preload
995 // java.lang.Object through resolve_or_fail, not this path.
996
997 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
998 class_loader,
999 protection_domain,
1000 host_klass,
1001 cp_patches,
1002 parsed_name,
1003 true,
1004 THREAD);
1005
1006 // We don't redefine the class, so we just need to clean up whether there
1007 // was an error or not (don't want to modify any system dictionary
1008 // data structures).
1009 // Parsed name could be null if we threw an error before we got far
1010 // enough along to parse it -- in that case, there is nothing to clean up.
1011 if (parsed_name != NULL) {
1012 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1013 class_loader);
1014 int p_index = placeholders()->hash_to_index(p_hash);
1015 {
1016 MutexLocker mu(SystemDictionary_lock, THREAD);
1017 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1018 SystemDictionary_lock->notify_all();
1019 }
1020 }
1021
1022 if (host_klass.not_null() && k.not_null()) {
1023 assert(EnableInvokeDynamic, "");
1024 // If it's anonymous, initialize it now, since nobody else will.
1025 k->set_host_klass(host_klass());
1026
1027 {
1028 MutexLocker mu_r(Compile_lock, THREAD);
1029
1030 // Add to class hierarchy, initialize vtables, and do possible
1031 // deoptimizations.
1032 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1033
1034 // But, do not add to system dictionary.
1035 }
1036
1037 k->eager_initialize(THREAD);
1038
1039 // notify jvmti
1040 if (JvmtiExport::should_post_class_load()) {
1041 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1042 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1043 }
1044 }
1045
1046 return k();
1047 }
1048
1049 // Add a klass to the system from a stream (called by jni_DefineClass and
1050 // JVM_DefineClass).
1051 // Note: class_name can be NULL. In that case we do not know the name of
1052 // the class until we have parsed the stream.
1053
1054 klassOop SystemDictionary::resolve_from_stream(Symbol* class_name,
1055 Handle class_loader,
1056 Handle protection_domain,
1057 ClassFileStream* st,
1058 bool verify,
1059 TRAPS) {
1060
1061 // Classloaders that support parallelism, e.g. bootstrap classloader,
1062 // or all classloaders with UnsyncloadClass do not acquire lock here
1063 bool DoObjectLock = true;
1064 if (is_parallelCapable(class_loader)) {
1065 DoObjectLock = false;
1066 }
1067
1068 // Make sure we are synchronized on the class loader before we proceed
1069 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1070 check_loader_lock_contention(lockObject, THREAD);
1071 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1072
1073 TempNewSymbol parsed_name = NULL;
1074
1075 // Parse the stream. Note that we do this even though this klass might
1076 // already be present in the SystemDictionary, otherwise we would not
1077 // throw potential ClassFormatErrors.
1078 //
1079 // Note: "name" is updated.
1080 // Further note: a placeholder will be added for this class when
1081 // super classes are loaded (resolve_super_or_fail). We expect this
1082 // to be called for all classes but java.lang.Object; and we preload
1083 // java.lang.Object through resolve_or_fail, not this path.
1084
1085 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1086 class_loader,
1087 protection_domain,
1088 parsed_name,
1089 verify,
1090 THREAD);
1091
1092 const char* pkg = "java/";
1093 if (!HAS_PENDING_EXCEPTION &&
1094 !class_loader.is_null() &&
1095 parsed_name != NULL &&
1096 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1097 // It is illegal to define classes in the "java." package from
1098 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1099 ResourceMark rm(THREAD);
1100 char* name = parsed_name->as_C_string();
1101 char* index = strrchr(name, '/');
1102 *index = '\0'; // chop to just the package name
1103 while ((index = strchr(name, '/')) != NULL) {
1104 *index = '.'; // replace '/' with '.' in package name
1105 }
1106 const char* fmt = "Prohibited package name: %s";
1107 size_t len = strlen(fmt) + strlen(name);
1108 char* message = NEW_RESOURCE_ARRAY(char, len);
1109 jio_snprintf(message, len, fmt, name);
1110 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1111 vmSymbols::java_lang_SecurityException(), message);
1112 }
1113
1114 if (!HAS_PENDING_EXCEPTION) {
1115 assert(parsed_name != NULL, "Sanity");
1116 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1117 // Verification prevents us from creating names with dots in them, this
1118 // asserts that that's the case.
1119 assert(is_internal_format(parsed_name),
1120 "external class name format used internally");
1121
1122 // Add class just loaded
1123 // If a class loader supports parallel classloading handle parallel define requests
1124 // find_or_define_instance_class may return a different instanceKlass
1125 if (is_parallelCapable(class_loader)) {
1126 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1127 } else {
1128 define_instance_class(k, THREAD);
1129 }
1130 }
1131
1132 // If parsing the class file or define_instance_class failed, we
1133 // need to remove the placeholder added on our behalf. But we
1134 // must make sure parsed_name is valid first (it won't be if we had
1135 // a format error before the class was parsed far enough to
1136 // find the name).
1137 if (HAS_PENDING_EXCEPTION && parsed_name != NULL) {
1138 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1139 class_loader);
1140 int p_index = placeholders()->hash_to_index(p_hash);
1141 {
1142 MutexLocker mu(SystemDictionary_lock, THREAD);
1143 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1144 SystemDictionary_lock->notify_all();
1145 }
1146 return NULL;
1147 }
1148
1149 // Make sure that we didn't leave a place holder in the
1150 // SystemDictionary; this is only done on success
1151 debug_only( {
1152 if (!HAS_PENDING_EXCEPTION) {
1153 assert(parsed_name != NULL, "parsed_name is still null?");
1154 Symbol* h_name = k->name();
1155 Handle h_loader (THREAD, k->class_loader());
1156
1157 MutexLocker mu(SystemDictionary_lock, THREAD);
1158
1159 klassOop check = find_class(parsed_name, class_loader);
1160 assert(check == k(), "should be present in the dictionary");
1161
1162 klassOop check2 = find_class(h_name, h_loader);
1163 assert(check == check2, "name inconsistancy in SystemDictionary");
1164 }
1165 } );
1166
1167 return k();
1168 }
1169
1170
1171 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1172 int number_of_entries) {
1173 assert(length == _nof_buckets * sizeof(HashtableBucket),
1174 "bad shared dictionary size.");
1175 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1176 }
1177
1178
1179 // If there is a shared dictionary, then find the entry for the
1180 // given shared system class, if any.
1181
1182 klassOop SystemDictionary::find_shared_class(Symbol* class_name) {
1183 if (shared_dictionary() != NULL) {
1184 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, Handle());
1185 int d_index = shared_dictionary()->hash_to_index(d_hash);
1186 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1187 } else {
1188 return NULL;
1189 }
1190 }
1191
1192
1193 // Load a class from the shared spaces (found through the shared system
1194 // dictionary). Force the superclass and all interfaces to be loaded.
1195 // Update the class definition to include sibling classes and no
1196 // subclasses (yet). [Classes in the shared space are not part of the
1197 // object hierarchy until loaded.]
1198
1199 instanceKlassHandle SystemDictionary::load_shared_class(
1200 Symbol* class_name, Handle class_loader, TRAPS) {
1201 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1202 return load_shared_class(ik, class_loader, THREAD);
1203 }
1204
1205 // Note well! Changes to this method may affect oop access order
1206 // in the shared archive. Please take care to not make changes that
1207 // adversely affect cold start time by changing the oop access order
1208 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1209 // MarkAndMoveOrderedReadWrite closures.
1210 instanceKlassHandle SystemDictionary::load_shared_class(
1211 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1212 assert(class_loader.is_null(), "non-null classloader for shared class?");
1213 if (ik.not_null()) {
1214 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1215 Symbol* class_name = ik->name();
1216
1217 // Found the class, now load the superclass and interfaces. If they
1218 // are shared, add them to the main system dictionary and reset
1219 // their hierarchy references (supers, subs, and interfaces).
1220
1221 if (ik->super() != NULL) {
1222 Symbol* cn = ik->super()->klass_part()->name();
1223 resolve_super_or_fail(class_name, cn,
1224 class_loader, Handle(), true, CHECK_(nh));
1225 }
1226
1227 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1228 int num_interfaces = interfaces->length();
1229 for (int index = 0; index < num_interfaces; index++) {
1230 klassOop k = klassOop(interfaces->obj_at(index));
1231
1232 // Note: can not use instanceKlass::cast here because
1233 // interfaces' instanceKlass's C++ vtbls haven't been
1234 // reinitialized yet (they will be once the interface classes
1235 // are loaded)
1236 Symbol* name = k->klass_part()->name();
1237 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1238 }
1239
1240 // Adjust methods to recover missing data. They need addresses for
1241 // interpreter entry points and their default native method address
1242 // must be reset.
1243
1244 // Updating methods must be done under a lock so multiple
1245 // threads don't update these in parallel
1246 // Shared classes are all currently loaded by the bootstrap
1247 // classloader, so this will never cause a deadlock on
1248 // a custom class loader lock.
1249
1250 {
1251 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1252 check_loader_lock_contention(lockObject, THREAD);
1253 ObjectLocker ol(lockObject, THREAD, true);
1254
1255 objArrayHandle methods (THREAD, ik->methods());
1256 int num_methods = methods->length();
1257 for (int index2 = 0; index2 < num_methods; ++index2) {
1258 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1259 m()->link_method(m, CHECK_(nh));
1260 }
1261 if (JvmtiExport::has_redefined_a_class()) {
1262 // Reinitialize vtable because RedefineClasses may have changed some
1263 // entries in this vtable for super classes so the CDS vtable might
1264 // point to old or obsolete entries. RedefineClasses doesn't fix up
1265 // vtables in the shared system dictionary, only the main one.
1266 // It also redefines the itable too so fix that too.
1267 ResourceMark rm(THREAD);
1268 ik->vtable()->initialize_vtable(false, CHECK_(nh));
1269 ik->itable()->initialize_itable(false, CHECK_(nh));
1270 }
1271 }
1272
1273 if (TraceClassLoading) {
1274 ResourceMark rm;
1275 tty->print("[Loaded %s", ik->external_name());
1276 tty->print(" from shared objects file");
1277 tty->print_cr("]");
1278 }
1279 // notify a class loaded from shared object
1280 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1281 true /* shared class */);
1282 }
1283 return ik;
1284 }
1285
1286 #ifdef KERNEL
1287 // Some classes on the bootstrap class path haven't been installed on the
1288 // system yet. Call the DownloadManager method to make them appear in the
1289 // bootstrap class path and try again to load the named class.
1290 // Note that with delegation class loaders all classes in another loader will
1291 // first try to call this so it'd better be fast!!
1292 static instanceKlassHandle download_and_retry_class_load(
1293 Symbol* class_name,
1294 TRAPS) {
1295
1296 klassOop dlm = SystemDictionary::DownloadManager_klass();
1297 instanceKlassHandle nk;
1298
1299 // If download manager class isn't loaded just return.
1300 if (dlm == NULL) return nk;
1301
1302 { HandleMark hm(THREAD);
1303 ResourceMark rm(THREAD);
1304 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1305 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1306
1307 // return value
1308 JavaValue result(T_OBJECT);
1309
1310 // Call the DownloadManager. We assume that it has a lock because
1311 // multiple classes could be not found and downloaded at the same time.
1312 // class sun.misc.DownloadManager;
1313 // public static String getBootClassPathEntryForClass(String className);
1314 JavaCalls::call_static(&result,
1315 KlassHandle(THREAD, dlm),
1316 vmSymbols::getBootClassPathEntryForClass_name(),
1317 vmSymbols::string_string_signature(),
1318 class_string,
1319 CHECK_(nk));
1320
1321 // Get result.string and add to bootclasspath
1322 assert(result.get_type() == T_OBJECT, "just checking");
1323 oop obj = (oop) result.get_jobject();
1324 if (obj == NULL) { return nk; }
1325
1326 Handle h_obj(THREAD, obj);
1327 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1328 CHECK_(nk));
1329
1330 // lock the loader
1331 // we use this lock because JVMTI does.
1332 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1333
1334 ObjectLocker ol(loader_lock, THREAD);
1335 // add the file to the bootclasspath
1336 ClassLoader::update_class_path_entry_list(new_class_name, true);
1337 } // end HandleMark
1338
1339 if (TraceClassLoading) {
1340 ClassLoader::print_bootclasspath();
1341 }
1342 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1343 }
1344 #endif // KERNEL
1345
1346
1347 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1348 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1349 if (class_loader.is_null()) {
1350
1351 // Search the shared system dictionary for classes preloaded into the
1352 // shared spaces.
1353 instanceKlassHandle k;
1354 {
1355 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1356 k = load_shared_class(class_name, class_loader, THREAD);
1357 }
1358
1359 if (k.is_null()) {
1360 // Use VM class loader
1361 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1362 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1363 }
1364
1365 #ifdef KERNEL
1366 // If the VM class loader has failed to load the class, call the
1367 // DownloadManager class to make it magically appear on the classpath
1368 // and try again. This is only configured with the Kernel VM.
1369 if (k.is_null()) {
1370 k = download_and_retry_class_load(class_name, CHECK_(nh));
1371 }
1372 #endif // KERNEL
1373
1374 // find_or_define_instance_class may return a different instanceKlass
1375 if (!k.is_null()) {
1376 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1377 }
1378 return k;
1379 } else {
1380 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1381 ResourceMark rm(THREAD);
1382
1383 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1384 JavaThread* jt = (JavaThread*) THREAD;
1385
1386 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1387 ClassLoader::perf_app_classload_selftime(),
1388 ClassLoader::perf_app_classload_count(),
1389 jt->get_thread_stat()->perf_recursion_counts_addr(),
1390 jt->get_thread_stat()->perf_timers_addr(),
1391 PerfClassTraceTime::CLASS_LOAD);
1392
1393 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1394 // Translate to external class name format, i.e., convert '/' chars to '.'
1395 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1396
1397 JavaValue result(T_OBJECT);
1398
1399 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1400
1401 // Call public unsynchronized loadClass(String) directly for all class loaders
1402 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1403 // acquire a class-name based lock rather than the class loader object lock.
1404 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1405 // so the call to loadClassInternal() was not required.
1406 //
1407 // UnsyncloadClass flag means both call loadClass(String) and do
1408 // not acquire the class loader lock even for class loaders that are
1409 // not parallelCapable. This was a risky transitional
1410 // flag for diagnostic purposes only. It is risky to call
1411 // custom class loaders without synchronization.
1412 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1413 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1414 // Do NOT assume this will be supported in future releases.
1415 //
1416 // Added MustCallLoadClassInternal in case we discover in the field
1417 // a customer that counts on this call
1418 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1419 JavaCalls::call_special(&result,
1420 class_loader,
1421 spec_klass,
1422 vmSymbols::loadClassInternal_name(),
1423 vmSymbols::string_class_signature(),
1424 string,
1425 CHECK_(nh));
1426 } else {
1427 JavaCalls::call_virtual(&result,
1428 class_loader,
1429 spec_klass,
1430 vmSymbols::loadClass_name(),
1431 vmSymbols::string_class_signature(),
1432 string,
1433 CHECK_(nh));
1434 }
1435
1436 assert(result.get_type() == T_OBJECT, "just checking");
1437 oop obj = (oop) result.get_jobject();
1438
1439 // Primitive classes return null since forName() can not be
1440 // used to obtain any of the Class objects representing primitives or void
1441 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1442 instanceKlassHandle k =
1443 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1444 // For user defined Java class loaders, check that the name returned is
1445 // the same as that requested. This check is done for the bootstrap
1446 // loader when parsing the class file.
1447 if (class_name == k->name()) {
1448 return k;
1449 }
1450 }
1451 // Class is not found or has the wrong name, return NULL
1452 return nh;
1453 }
1454 }
1455
1456 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1457
1458 Handle class_loader_h(THREAD, k->class_loader());
1459
1460 // for bootstrap and other parallel classloaders don't acquire lock,
1461 // use placeholder token
1462 // If a parallelCapable class loader calls define_instance_class instead of
1463 // find_or_define_instance_class to get here, we have a timing
1464 // hole with systemDictionary updates and check_constraints
1465 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1466 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1467 compute_loader_lock_object(class_loader_h, THREAD)),
1468 "define called without lock");
1469 }
1470
1471 // Check class-loading constraints. Throw exception if violation is detected.
1472 // Grabs and releases SystemDictionary_lock
1473 // The check_constraints/find_class call and update_dictionary sequence
1474 // must be "atomic" for a specific class/classloader pair so we never
1475 // define two different instanceKlasses for that class/classloader pair.
1476 // Existing classloaders will call define_instance_class with the
1477 // classloader lock held
1478 // Parallel classloaders will call find_or_define_instance_class
1479 // which will require a token to perform the define class
1480 Symbol* name_h = k->name();
1481 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1482 int d_index = dictionary()->hash_to_index(d_hash);
1483 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1484
1485 // Register class just loaded with class loader (placed in Vector)
1486 // Note we do this before updating the dictionary, as this can
1487 // fail with an OutOfMemoryError (if it does, we will *not* put this
1488 // class in the dictionary and will not update the class hierarchy).
1489 if (k->class_loader() != NULL) {
1490 methodHandle m(THREAD, Universe::loader_addClass_method());
1491 JavaValue result(T_VOID);
1492 JavaCallArguments args(class_loader_h);
1493 args.push_oop(Handle(THREAD, k->java_mirror()));
1494 JavaCalls::call(&result, m, &args, CHECK);
1495 }
1496
1497 // Add the new class. We need recompile lock during update of CHA.
1498 {
1499 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1500 int p_index = placeholders()->hash_to_index(p_hash);
1501
1502 MutexLocker mu_r(Compile_lock, THREAD);
1503
1504 // Add to class hierarchy, initialize vtables, and do possible
1505 // deoptimizations.
1506 add_to_hierarchy(k, CHECK); // No exception, but can block
1507
1508 // Add to systemDictionary - so other classes can see it.
1509 // Grabs and releases SystemDictionary_lock
1510 update_dictionary(d_index, d_hash, p_index, p_hash,
1511 k, class_loader_h, THREAD);
1512 }
1513 k->eager_initialize(THREAD);
1514
1515 // notify jvmti
1516 if (JvmtiExport::should_post_class_load()) {
1517 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1518 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1519
1520 }
1521 }
1522
1523 // Support parallel classloading
1524 // All parallel class loaders, including bootstrap classloader
1525 // lock a placeholder entry for this class/class_loader pair
1526 // to allow parallel defines of different classes for this class loader
1527 // With AllowParallelDefine flag==true, in case they do not synchronize around
1528 // FindLoadedClass/DefineClass, calls, we check for parallel
1529 // loading for them, wait if a defineClass is in progress
1530 // and return the initial requestor's results
1531 // This flag does not apply to the bootstrap classloader.
1532 // With AllowParallelDefine flag==false, call through to define_instance_class
1533 // which will throw LinkageError: duplicate class definition.
1534 // False is the requested default.
1535 // For better performance, the class loaders should synchronize
1536 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1537 // potentially waste time reading and parsing the bytestream.
1538 // Note: VM callers should ensure consistency of k/class_name,class_loader
1539 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1540
1541 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1542 Symbol* name_h = k->name(); // passed in class_name may be null
1543
1544 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader);
1545 int d_index = dictionary()->hash_to_index(d_hash);
1546
1547 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1548 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader);
1549 int p_index = placeholders()->hash_to_index(p_hash);
1550 PlaceholderEntry* probe;
1551
1552 {
1553 MutexLocker mu(SystemDictionary_lock, THREAD);
1554 // First check if class already defined
1555 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1556 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1557 if (check != NULL) {
1558 return(instanceKlassHandle(THREAD, check));
1559 }
1560 }
1561
1562 // Acquire define token for this class/classloader
1563 probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1564 // Wait if another thread defining in parallel
1565 // All threads wait - even those that will throw duplicate class: otherwise
1566 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1567 // if other thread has not finished updating dictionary
1568 while (probe->definer() != NULL) {
1569 SystemDictionary_lock->wait();
1570 }
1571 // Only special cases allow parallel defines and can use other thread's results
1572 // Other cases fall through, and may run into duplicate defines
1573 // caught by finding an entry in the SystemDictionary
1574 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) {
1575 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1576 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1577 SystemDictionary_lock->notify_all();
1578 #ifdef ASSERT
1579 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1580 assert(check != NULL, "definer missed recording success");
1581 #endif
1582 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1583 } else {
1584 // This thread will define the class (even if earlier thread tried and had an error)
1585 probe->set_definer(THREAD);
1586 }
1587 }
1588
1589 define_instance_class(k, THREAD);
1590
1591 Handle linkage_exception = Handle(); // null handle
1592
1593 // definer must notify any waiting threads
1594 {
1595 MutexLocker mu(SystemDictionary_lock, THREAD);
1596 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader);
1597 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1598 if (probe != NULL) {
1599 if (HAS_PENDING_EXCEPTION) {
1600 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1601 CLEAR_PENDING_EXCEPTION;
1602 } else {
1603 probe->set_instanceKlass(k());
1604 }
1605 probe->set_definer(NULL);
1606 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1607 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1608 SystemDictionary_lock->notify_all();
1609 }
1610 }
1611
1612 // Can't throw exception while holding lock due to rank ordering
1613 if (linkage_exception() != NULL) {
1614 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1615 }
1616
1617 return k;
1618 }
1619 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1620 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1621 if (class_loader.is_null()) {
1622 return Handle(THREAD, _system_loader_lock_obj);
1623 } else {
1624 return class_loader;
1625 }
1626 }
1627
1628 // This method is added to check how often we have to wait to grab loader
1629 // lock. The results are being recorded in the performance counters defined in
1630 // ClassLoader::_sync_systemLoaderLockContentionRate and
1631 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1632 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1633 if (!UsePerfData) {
1634 return;
1635 }
1636
1637 assert(!loader_lock.is_null(), "NULL lock object");
1638
1639 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1640 == ObjectSynchronizer::owner_other) {
1641 // contention will likely happen, so increment the corresponding
1642 // contention counter.
1643 if (loader_lock() == _system_loader_lock_obj) {
1644 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1645 } else {
1646 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1647 }
1648 }
1649 }
1650
1651 // ----------------------------------------------------------------------------
1652 // Lookup
1653
1654 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1655 Symbol* class_name,
1656 Handle class_loader) {
1657 assert_locked_or_safepoint(SystemDictionary_lock);
1658 assert (index == dictionary()->index_for(class_name, class_loader),
1659 "incorrect index?");
1660
1661 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1662 return k;
1663 }
1664
1665
1666 // Basic find on classes in the midst of being loaded
1667 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1668 Handle class_loader) {
1669 assert_locked_or_safepoint(SystemDictionary_lock);
1670 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1671 int p_index = placeholders()->hash_to_index(p_hash);
1672 return placeholders()->find_entry(p_index, p_hash, class_name, class_loader);
1673 }
1674
1675
1676 // Used for assertions and verification only
1677 klassOop SystemDictionary::find_class(Symbol* class_name, Handle class_loader) {
1678 #ifndef ASSERT
1679 guarantee(VerifyBeforeGC ||
1680 VerifyDuringGC ||
1681 VerifyBeforeExit ||
1682 VerifyAfterGC, "too expensive");
1683 #endif
1684 assert_locked_or_safepoint(SystemDictionary_lock);
1685
1686 // First look in the loaded class array
1687 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1688 int d_index = dictionary()->hash_to_index(d_hash);
1689 return find_class(d_index, d_hash, class_name, class_loader);
1690 }
1691
1692
1693 // Get the next class in the diictionary.
1694 klassOop SystemDictionary::try_get_next_class() {
1695 return dictionary()->try_get_next_class();
1696 }
1697
1698
1699 // ----------------------------------------------------------------------------
1700 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1701 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1702 // before a new class is used.
1703
1704 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1705 assert(k.not_null(), "just checking");
1706 assert_locked_or_safepoint(Compile_lock);
1707
1708 // Link into hierachy. Make sure the vtables are initialized before linking into
1709 k->append_to_sibling_list(); // add to superklass/sibling list
1710 k->process_interfaces(THREAD); // handle all "implements" declarations
1711 k->set_init_state(instanceKlass::loaded);
1712 // Now flush all code that depended on old class hierarchy.
1713 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1714 // Also, first reinitialize vtable because it may have gotten out of synch
1715 // while the new class wasn't connected to the class hierarchy.
1716 Universe::flush_dependents_on(k);
1717 }
1718
1719
1720 // ----------------------------------------------------------------------------
1721 // GC support
1722
1723 // Following roots during mark-sweep is separated in two phases.
1724 //
1725 // The first phase follows preloaded classes and all other system
1726 // classes, since these will never get unloaded anyway.
1727 //
1728 // The second phase removes (unloads) unreachable classes from the
1729 // system dictionary and follows the remaining classes' contents.
1730
1731 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1732 // Follow preloaded classes/mirrors and system loader object
1733 blk->do_oop(&_java_system_loader);
1734 preloaded_oops_do(blk);
1735 always_strong_classes_do(blk);
1736 }
1737
1738
1739 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1740 // Follow all system classes and temporary placeholders in dictionary
1741 dictionary()->always_strong_classes_do(blk);
1742
1743 // Placeholders. These are *always* strong roots, as they
1744 // represent classes we're actively loading.
1745 placeholders_do(blk);
1746
1747 // Visit extra methods
1748 invoke_method_table()->oops_do(blk);
1749 }
1750
1751
1752 void SystemDictionary::placeholders_do(OopClosure* blk) {
1753 placeholders()->oops_do(blk);
1754 }
1755
1756 // Calculate a "good" systemdictionary size based
1757 // on predicted or current loaded classes count
1758 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1759 int newsize = _old_default_sdsize;
1760 if ((classcount > 0) && !DumpSharedSpaces) {
1761 int desiredsize = classcount/_average_depth_goal;
1762 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1763 newsize = _primelist[++_sdgeneration]) {
1764 if (desiredsize <= newsize) {
1765 break;
1766 }
1767 }
1768 }
1769 return newsize;
1770 }
1771 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1772 bool result = dictionary()->do_unloading(is_alive);
1773 constraints()->purge_loader_constraints(is_alive);
1774 resolution_errors()->purge_resolution_errors(is_alive);
1775 return result;
1776 }
1777
1778
1779 // The mirrors are scanned by shared_oops_do() which is
1780 // not called by oops_do(). In order to process oops in
1781 // a necessary order, shared_oops_do() is call by
1782 // Universe::oops_do().
1783 void SystemDictionary::oops_do(OopClosure* f) {
1784 // Adjust preloaded classes and system loader object
1785 f->do_oop(&_java_system_loader);
1786 preloaded_oops_do(f);
1787
1788 lazily_loaded_oops_do(f);
1789
1790 // Adjust dictionary
1791 dictionary()->oops_do(f);
1792
1793 // Visit extra methods
1794 invoke_method_table()->oops_do(f);
1795
1796 // Partially loaded classes
1797 placeholders()->oops_do(f);
1798
1799 // Adjust constraint table
1800 constraints()->oops_do(f);
1801
1802 // Adjust resolution error table
1803 resolution_errors()->oops_do(f);
1804 }
1805
1806
1807 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1808 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1809 f->do_oop((oop*) &_well_known_klasses[k]);
1810 }
1811
1812 {
1813 for (int i = 0; i < T_VOID+1; i++) {
1814 if (_box_klasses[i] != NULL) {
1815 assert(i >= T_BOOLEAN, "checking");
1816 f->do_oop((oop*) &_box_klasses[i]);
1817 }
1818 }
1819 }
1820
1821 // The basic type mirrors would have already been processed in
1822 // Universe::oops_do(), via a call to shared_oops_do(), so should
1823 // not be processed again.
1824
1825 f->do_oop((oop*) &_system_loader_lock_obj);
1826 FilteredFieldsMap::klasses_oops_do(f);
1827 }
1828
1829 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1830 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1831 }
1832
1833 // Just the classes from defining class loaders
1834 // Don't iterate over placeholders
1835 void SystemDictionary::classes_do(void f(klassOop)) {
1836 dictionary()->classes_do(f);
1837 }
1838
1839 // Added for initialize_itable_for_klass
1840 // Just the classes from defining class loaders
1841 // Don't iterate over placeholders
1842 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1843 dictionary()->classes_do(f, CHECK);
1844 }
1845
1846 // All classes, and their class loaders
1847 // Don't iterate over placeholders
1848 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1849 dictionary()->classes_do(f);
1850 }
1851
1852 // All classes, and their class loaders
1853 // (added for helpers that use HandleMarks and ResourceMarks)
1854 // Don't iterate over placeholders
1855 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1856 dictionary()->classes_do(f, CHECK);
1857 }
1858
1859 void SystemDictionary::placeholders_do(void f(Symbol*, oop)) {
1860 placeholders()->entries_do(f);
1861 }
1862
1863 void SystemDictionary::methods_do(void f(methodOop)) {
1864 dictionary()->methods_do(f);
1865 invoke_method_table()->methods_do(f);
1866 }
1867
1868 // ----------------------------------------------------------------------------
1869 // Lazily load klasses
1870
1871 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1872 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1873
1874 // if multiple threads calling this function, only one thread will load
1875 // the class. The other threads will find the loaded version once the
1876 // class is loaded.
1877 klassOop aos = _abstract_ownable_synchronizer_klass;
1878 if (aos == NULL) {
1879 klassOop k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1880 // Force a fence to prevent any read before the write completes
1881 OrderAccess::fence();
1882 _abstract_ownable_synchronizer_klass = k;
1883 }
1884 }
1885
1886 // ----------------------------------------------------------------------------
1887 // Initialization
1888
1889 void SystemDictionary::initialize(TRAPS) {
1890 // Allocate arrays
1891 assert(dictionary() == NULL,
1892 "SystemDictionary should only be initialized once");
1893 _sdgeneration = 0;
1894 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1895 _placeholders = new PlaceholderTable(_nof_buckets);
1896 _number_of_modifications = 0;
1897 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1898 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1899 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1900
1901 // Allocate private object used as system class loader lock
1902 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1903 // Initialize basic classes
1904 initialize_preloaded_classes(CHECK);
1905 }
1906
1907 // Compact table of directions on the initialization of klasses:
1908 static const short wk_init_info[] = {
1909 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1910 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1911 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1912 | (int)SystemDictionary::option ),
1913 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1914 #undef WK_KLASS_INIT_INFO
1915 0
1916 };
1917
1918 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1919 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1920 int info = wk_init_info[id - FIRST_WKID];
1921 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1922 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1923 klassOop* klassp = &_well_known_klasses[id];
1924 bool must_load = (init_opt < SystemDictionary::Opt);
1925 bool try_load = true;
1926 if (init_opt == SystemDictionary::Opt_Kernel) {
1927 #ifndef KERNEL
1928 try_load = false;
1929 #endif //KERNEL
1930 }
1931 if ((*klassp) == NULL && try_load) {
1932 if (must_load) {
1933 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1934 } else {
1935 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1936 }
1937 }
1938 return ((*klassp) != NULL);
1939 }
1940
1941 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1942 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1943 for (int id = (int)start_id; id < (int)limit_id; id++) {
1944 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1945 int info = wk_init_info[id - FIRST_WKID];
1946 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1947 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1948
1949 initialize_wk_klass((WKID)id, opt, CHECK);
1950
1951 // Update limits, so find_well_known_klass can be very fast:
1952 Symbol* s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1953 if (wk_klass_name_limits[1] == NULL) {
1954 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1955 } else if (wk_klass_name_limits[1] < s) {
1956 wk_klass_name_limits[1] = s;
1957 } else if (wk_klass_name_limits[0] > s) {
1958 wk_klass_name_limits[0] = s;
1959 }
1960 }
1961
1962 // move the starting value forward to the limit:
1963 start_id = limit_id;
1964 }
1965
1966
1967 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1968 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1969 // Preload commonly used klasses
1970 WKID scan = FIRST_WKID;
1971 // first do Object, String, Class
1972 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1973
1974 java_lang_Class::compute_offsets();
1975
1976 // Fixup mirrors for classes loaded before java.lang.Class.
1977 // These calls iterate over the objects currently in the perm gen
1978 // so calling them at this point is matters (not before when there
1979 // are fewer objects and not later after there are more objects
1980 // in the perm gen.
1981 Universe::initialize_basic_type_mirrors(CHECK);
1982 Universe::fixup_mirrors(CHECK);
1983
1984 // do a bunch more:
1985 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1986
1987 // Preload ref klasses and set reference types
1988 instanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1989 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1990
1991 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1992 instanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1993 instanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1994 instanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1995 instanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1996
1997 // JSR 292 classes
1998 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1999 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2000 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2001 if (EnableInvokeDynamic) {
2002 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2003 } else {
2004 // Skip the JSR 292 classes, if not enabled.
2005 scan = WKID(jsr292_group_end + 1);
2006 }
2007
2008 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
2009
2010 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2011 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2012 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2013 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2014 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2015 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2016 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2017 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2018 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2019 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2020
2021 #ifdef KERNEL
2022 if (DownloadManager_klass() == NULL) {
2023 warning("Cannot find sun/jkernel/DownloadManager");
2024 }
2025 #endif // KERNEL
2026
2027 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2028 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2029 _has_loadClassInternal = (method != NULL);
2030 }
2031 { // Compute whether we should use checkPackageAccess or NOT
2032 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2033 _has_checkPackageAccess = (method != NULL);
2034 }
2035 }
2036
2037 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2038 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2039 BasicType SystemDictionary::box_klass_type(klassOop k) {
2040 assert(k != NULL, "");
2041 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2042 if (_box_klasses[i] == k)
2043 return (BasicType)i;
2044 }
2045 return T_OBJECT;
2046 }
2047
2048 KlassHandle SystemDictionaryHandles::box_klass(BasicType t) {
2049 if (t >= T_BOOLEAN && t <= T_VOID)
2050 return KlassHandle(&SystemDictionary::_box_klasses[t], true);
2051 else
2052 return KlassHandle();
2053 }
2054
2055 // Constraints on class loaders. The details of the algorithm can be
2056 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2057 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2058 // that the system dictionary needs to maintain a set of contraints that
2059 // must be satisfied by all classes in the dictionary.
2060 // if defining is true, then LinkageError if already in systemDictionary
2061 // if initiating loader, then ok if instanceKlass matches existing entry
2062
2063 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2064 instanceKlassHandle k,
2065 Handle class_loader, bool defining,
2066 TRAPS) {
2067 const char *linkage_error = NULL;
2068 {
2069 Symbol* name = k->name();
2070 MutexLocker mu(SystemDictionary_lock, THREAD);
2071
2072 klassOop check = find_class(d_index, d_hash, name, class_loader);
2073 if (check != (klassOop)NULL) {
2074 // if different instanceKlass - duplicate class definition,
2075 // else - ok, class loaded by a different thread in parallel,
2076 // we should only have found it if it was done loading and ok to use
2077 // system dictionary only holds instance classes, placeholders
2078 // also holds array classes
2079
2080 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2081 if ((defining == true) || (k() != check)) {
2082 linkage_error = "loader (instance of %s): attempted duplicate class "
2083 "definition for name: \"%s\"";
2084 } else {
2085 return;
2086 }
2087 }
2088
2089 #ifdef ASSERT
2090 Symbol* ph_check = find_placeholder(name, class_loader);
2091 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2092 #endif
2093
2094 if (linkage_error == NULL) {
2095 if (constraints()->check_or_update(k, class_loader, name) == false) {
2096 linkage_error = "loader constraint violation: loader (instance of %s)"
2097 " previously initiated loading for a different type with name \"%s\"";
2098 }
2099 }
2100 }
2101
2102 // Throw error now if needed (cannot throw while holding
2103 // SystemDictionary_lock because of rank ordering)
2104
2105 if (linkage_error) {
2106 ResourceMark rm(THREAD);
2107 const char* class_loader_name = loader_name(class_loader());
2108 char* type_name = k->name()->as_C_string();
2109 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2110 strlen(type_name);
2111 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2112 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2113 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2114 }
2115 }
2116
2117
2118 // Update system dictionary - done after check_constraint and add_to_hierachy
2119 // have been called.
2120 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2121 int p_index, unsigned int p_hash,
2122 instanceKlassHandle k,
2123 Handle class_loader,
2124 TRAPS) {
2125 // Compile_lock prevents systemDictionary updates during compilations
2126 assert_locked_or_safepoint(Compile_lock);
2127 Symbol* name = k->name();
2128
2129 {
2130 MutexLocker mu1(SystemDictionary_lock, THREAD);
2131
2132 // See whether biased locking is enabled and if so set it for this
2133 // klass.
2134 // Note that this must be done past the last potential blocking
2135 // point / safepoint. We enable biased locking lazily using a
2136 // VM_Operation to iterate the SystemDictionary and installing the
2137 // biasable mark word into each instanceKlass's prototype header.
2138 // To avoid race conditions where we accidentally miss enabling the
2139 // optimization for one class in the process of being added to the
2140 // dictionary, we must not safepoint after the test of
2141 // BiasedLocking::enabled().
2142 if (UseBiasedLocking && BiasedLocking::enabled()) {
2143 // Set biased locking bit for all loaded classes; it will be
2144 // cleared if revocation occurs too often for this type
2145 // NOTE that we must only do this when the class is initally
2146 // defined, not each time it is referenced from a new class loader
2147 if (k->class_loader() == class_loader()) {
2148 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2149 }
2150 }
2151
2152 // Assign a classid if one has not already been assigned. The
2153 // counter does not need to be atomically incremented since this
2154 // is only done while holding the SystemDictionary_lock.
2155 // All loaded classes get a unique ID.
2156 TRACE_INIT_ID(k);
2157
2158 // Check for a placeholder. If there, remove it and make a
2159 // new system dictionary entry.
2160 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2161 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2162 if (sd_check == NULL) {
2163 dictionary()->add_klass(name, class_loader, k);
2164 notice_modification();
2165 }
2166 #ifdef ASSERT
2167 sd_check = find_class(d_index, d_hash, name, class_loader);
2168 assert (sd_check != NULL, "should have entry in system dictionary");
2169 // Changed to allow PH to remain to complete class circularity checking
2170 // while only one thread can define a class at one time, multiple
2171 // classes can resolve the superclass for a class at one time,
2172 // and the placeholder is used to track that
2173 // Symbol* ph_check = find_placeholder(name, class_loader);
2174 // assert (ph_check == NULL, "should not have a placeholder entry");
2175 #endif
2176 SystemDictionary_lock->notify_all();
2177 }
2178 }
2179
2180
2181 // Try to find a class name using the loader constraints. The
2182 // loader constraints might know about a class that isn't fully loaded
2183 // yet and these will be ignored.
2184 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2185 Symbol* class_name, Handle class_loader, TRAPS) {
2186
2187 // First see if it has been loaded directly.
2188 // Force the protection domain to be null. (This removes protection checks.)
2189 Handle no_protection_domain;
2190 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2191 no_protection_domain, CHECK_NULL);
2192 if (klass != NULL)
2193 return klass;
2194
2195 // Now look to see if it has been loaded elsewhere, and is subject to
2196 // a loader constraint that would require this loader to return the
2197 // klass that is already loaded.
2198 if (FieldType::is_array(class_name)) {
2199 // For array classes, their klassOops are not kept in the
2200 // constraint table. The element klassOops are.
2201 FieldArrayInfo fd;
2202 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2203 if (t != T_OBJECT) {
2204 klass = Universe::typeArrayKlassObj(t);
2205 } else {
2206 MutexLocker mu(SystemDictionary_lock, THREAD);
2207 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2208 }
2209 // If element class already loaded, allocate array klass
2210 if (klass != NULL) {
2211 klass = Klass::cast(klass)->array_klass_or_null(fd.dimension());
2212 }
2213 } else {
2214 MutexLocker mu(SystemDictionary_lock, THREAD);
2215 // Non-array classes are easy: simply check the constraint table.
2216 klass = constraints()->find_constrained_klass(class_name, class_loader);
2217 }
2218
2219 return klass;
2220 }
2221
2222
2223 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2224 Handle class_loader1,
2225 Handle class_loader2,
2226 Thread* THREAD) {
2227 Symbol* constraint_name = NULL;
2228 if (!FieldType::is_array(class_name)) {
2229 constraint_name = class_name;
2230 } else {
2231 // For array classes, their klassOops are not kept in the
2232 // constraint table. The element classes are.
2233 FieldArrayInfo fd;
2234 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2235 // primitive types always pass
2236 if (t != T_OBJECT) {
2237 return true;
2238 } else {
2239 constraint_name = fd.object_key();
2240 }
2241 }
2242 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, class_loader1);
2243 int d_index1 = dictionary()->hash_to_index(d_hash1);
2244
2245 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, class_loader2);
2246 int d_index2 = dictionary()->hash_to_index(d_hash2);
2247 {
2248 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2249
2250 // Better never do a GC while we're holding these oops
2251 No_Safepoint_Verifier nosafepoint;
2252
2253 klassOop klass1 = find_class(d_index1, d_hash1, constraint_name, class_loader1);
2254 klassOop klass2 = find_class(d_index2, d_hash2, constraint_name, class_loader2);
2255 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2256 klass2, class_loader2);
2257 }
2258 }
2259
2260 // Add entry to resolution error table to record the error when the first
2261 // attempt to resolve a reference to a class has failed.
2262 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2263 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2264 int index = resolution_errors()->hash_to_index(hash);
2265 {
2266 MutexLocker ml(SystemDictionary_lock, Thread::current());
2267 resolution_errors()->add_entry(index, hash, pool, which, error);
2268 }
2269 }
2270
2271 // Lookup resolution error table. Returns error if found, otherwise NULL.
2272 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2273 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2274 int index = resolution_errors()->hash_to_index(hash);
2275 {
2276 MutexLocker ml(SystemDictionary_lock, Thread::current());
2277 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2278 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2279 }
2280 }
2281
2282
2283 // Signature constraints ensure that callers and callees agree about
2284 // the meaning of type names in their signatures. This routine is the
2285 // intake for constraints. It collects them from several places:
2286 //
2287 // * LinkResolver::resolve_method (if check_access is true) requires
2288 // that the resolving class (the caller) and the defining class of
2289 // the resolved method (the callee) agree on each type in the
2290 // method's signature.
2291 //
2292 // * LinkResolver::resolve_interface_method performs exactly the same
2293 // checks.
2294 //
2295 // * LinkResolver::resolve_field requires that the constant pool
2296 // attempting to link to a field agree with the field's defining
2297 // class about the type of the field signature.
2298 //
2299 // * klassVtable::initialize_vtable requires that, when a class
2300 // overrides a vtable entry allocated by a superclass, that the
2301 // overriding method (i.e., the callee) agree with the superclass
2302 // on each type in the method's signature.
2303 //
2304 // * klassItable::initialize_itable requires that, when a class fills
2305 // in its itables, for each non-abstract method installed in an
2306 // itable, the method (i.e., the callee) agree with the interface
2307 // on each type in the method's signature.
2308 //
2309 // All those methods have a boolean (check_access, checkconstraints)
2310 // which turns off the checks. This is used from specialized contexts
2311 // such as bootstrapping, dumping, and debugging.
2312 //
2313 // No direct constraint is placed between the class and its
2314 // supertypes. Constraints are only placed along linked relations
2315 // between callers and callees. When a method overrides or implements
2316 // an abstract method in a supertype (superclass or interface), the
2317 // constraints are placed as if the supertype were the caller to the
2318 // overriding method. (This works well, since callers to the
2319 // supertype have already established agreement between themselves and
2320 // the supertype.) As a result of all this, a class can disagree with
2321 // its supertype about the meaning of a type name, as long as that
2322 // class neither calls a relevant method of the supertype, nor is
2323 // called (perhaps via an override) from the supertype.
2324 //
2325 //
2326 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2327 //
2328 // Make sure all class components (including arrays) in the given
2329 // signature will be resolved to the same class in both loaders.
2330 // Returns the name of the type that failed a loader constraint check, or
2331 // NULL if no constraint failed. The returned C string needs cleaning up
2332 // with a ResourceMark in the caller. No exception except OOME is thrown.
2333 // Arrays are not added to the loader constraint table, their elements are.
2334 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2335 Handle loader1, Handle loader2,
2336 bool is_method, TRAPS) {
2337 // Nothing to do if loaders are the same.
2338 if (loader1() == loader2()) {
2339 return NULL;
2340 }
2341
2342 ResourceMark rm(THREAD);
2343 SignatureStream sig_strm(signature, is_method);
2344 while (!sig_strm.is_done()) {
2345 if (sig_strm.is_object()) {
2346 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2347 Symbol* sig = s;
2348 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2349 return sig->as_C_string();
2350 }
2351 }
2352 sig_strm.next();
2353 }
2354 return NULL;
2355 }
2356
2357
2358 methodOop SystemDictionary::find_method_handle_invoke(Symbol* name,
2359 Symbol* signature,
2360 KlassHandle accessing_klass,
2361 TRAPS) {
2362 if (!EnableInvokeDynamic) return NULL;
2363 vmSymbols::SID name_id = vmSymbols::find_sid(name);
2364 assert(name_id != vmSymbols::NO_SID, "must be a known name");
2365 unsigned int hash = invoke_method_table()->compute_hash(signature, name_id);
2366 int index = invoke_method_table()->hash_to_index(hash);
2367 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, name_id);
2368 methodHandle non_cached_result;
2369 if (spe == NULL || spe->property_oop() == NULL) {
2370 spe = NULL;
2371 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2372 if (THREAD->is_Compiler_thread())
2373 return NULL; // do not attempt from within compiler
2374 bool for_invokeGeneric = (name_id != vmSymbols::VM_SYMBOL_ENUM_NAME(invokeExact_name));
2375 bool found_on_bcp = false;
2376 Handle mt = find_method_handle_type(signature, accessing_klass,
2377 for_invokeGeneric,
2378 found_on_bcp, CHECK_NULL);
2379 KlassHandle mh_klass = SystemDictionaryHandles::MethodHandle_klass();
2380 methodHandle m = methodOopDesc::make_invoke_method(mh_klass, name, signature,
2381 mt, CHECK_NULL);
2382 // Now grab the lock. We might have to throw away the new method,
2383 // if a racing thread has managed to install one at the same time.
2384 if (found_on_bcp) {
2385 MutexLocker ml(SystemDictionary_lock, Thread::current());
2386 spe = invoke_method_table()->find_entry(index, hash, signature, name_id);
2387 if (spe == NULL)
2388 spe = invoke_method_table()->add_entry(index, hash, signature, name_id);
2389 if (spe->property_oop() == NULL) {
2390 spe->set_property_oop(m());
2391 // Link m to his method type, if it is suitably generic.
2392 oop mtform = java_lang_invoke_MethodType::form(mt());
2393 if (mtform != NULL && mt() == java_lang_invoke_MethodTypeForm::erasedType(mtform)
2394 // vmlayout must be an invokeExact:
2395 && name_id == vmSymbols::VM_SYMBOL_ENUM_NAME(invokeExact_name)
2396 && java_lang_invoke_MethodTypeForm::vmlayout_offset_in_bytes() > 0) {
2397 java_lang_invoke_MethodTypeForm::init_vmlayout(mtform, m());
2398 }
2399 }
2400 } else {
2401 non_cached_result = m;
2402 }
2403 }
2404 if (spe != NULL && spe->property_oop() != NULL) {
2405 assert(spe->property_oop()->is_method(), "");
2406 return (methodOop) spe->property_oop();
2407 } else {
2408 return non_cached_result();
2409 }
2410 }
2411
2412 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2413 // signature, as interpreted relative to the given class loader.
2414 // Because of class loader constraints, all method handle usage must be
2415 // consistent with this loader.
2416 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2417 KlassHandle accessing_klass,
2418 bool for_invokeGeneric,
2419 bool& return_bcp_flag,
2420 TRAPS) {
2421 Handle class_loader, protection_domain;
2422 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2423 Handle empty;
2424 int npts = ArgumentCount(signature).size();
2425 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2426 int arg = 0;
2427 Handle rt; // the return type from the signature
2428 ResourceMark rm(THREAD);
2429 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2430 oop mirror = NULL;
2431 if (is_on_bcp) {
2432 mirror = ss.as_java_mirror(class_loader, protection_domain,
2433 SignatureStream::ReturnNull, CHECK_(empty));
2434 if (mirror == NULL) {
2435 // fall back from BCP to accessing_klass
2436 if (accessing_klass.not_null()) {
2437 class_loader = Handle(THREAD, instanceKlass::cast(accessing_klass())->class_loader());
2438 protection_domain = Handle(THREAD, instanceKlass::cast(accessing_klass())->protection_domain());
2439 }
2440 is_on_bcp = false;
2441 }
2442 }
2443 if (!is_on_bcp) {
2444 // Resolve, throwing a real error if it doesn't work.
2445 mirror = ss.as_java_mirror(class_loader, protection_domain,
2446 SignatureStream::NCDFError, CHECK_(empty));
2447 }
2448 if (ss.at_return_type())
2449 rt = Handle(THREAD, mirror);
2450 else
2451 pts->obj_at_put(arg++, mirror);
2452 // Check accessibility.
2453 if (ss.is_object() && accessing_klass.not_null()) {
2454 klassOop sel_klass = java_lang_Class::as_klassOop(mirror);
2455 // Emulate constantPoolOopDesc::verify_constant_pool_resolve.
2456 if (Klass::cast(sel_klass)->oop_is_objArray())
2457 sel_klass = objArrayKlass::cast(sel_klass)->bottom_klass();
2458 if (Klass::cast(sel_klass)->oop_is_instance()) {
2459 KlassHandle sel_kh(THREAD, sel_klass);
2460 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2461 }
2462 }
2463 }
2464 assert(arg == npts, "");
2465
2466 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2467 JavaCallArguments args(Handle(THREAD, rt()));
2468 args.push_oop(pts());
2469 JavaValue result(T_OBJECT);
2470 JavaCalls::call_static(&result,
2471 SystemDictionary::MethodHandleNatives_klass(),
2472 vmSymbols::findMethodHandleType_name(),
2473 vmSymbols::findMethodHandleType_signature(),
2474 &args, CHECK_(empty));
2475 Handle method_type(THREAD, (oop) result.get_jobject());
2476
2477 if (for_invokeGeneric) {
2478 // call java.lang.invoke.MethodHandleNatives::notifyGenericMethodType(MethodType) -> void
2479 JavaCallArguments args(Handle(THREAD, method_type()));
2480 JavaValue no_result(T_VOID);
2481 JavaCalls::call_static(&no_result,
2482 SystemDictionary::MethodHandleNatives_klass(),
2483 vmSymbols::notifyGenericMethodType_name(),
2484 vmSymbols::notifyGenericMethodType_signature(),
2485 &args, THREAD);
2486 if (HAS_PENDING_EXCEPTION) {
2487 // If the notification fails, just kill it.
2488 CLEAR_PENDING_EXCEPTION;
2489 }
2490 }
2491
2492 // report back to the caller with the MethodType and the "on_bcp" flag
2493 return_bcp_flag = is_on_bcp;
2494 return method_type;
2495 }
2496
2497 // Ask Java code to find or construct a method handle constant.
2498 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2499 int ref_kind, //e.g., JVM_REF_invokeVirtual
2500 KlassHandle callee,
2501 Symbol* name_sym,
2502 Symbol* signature,
2503 TRAPS) {
2504 Handle empty;
2505 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2506 Handle type;
2507 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2508 bool ignore_is_on_bcp = false;
2509 type = find_method_handle_type(signature, caller, false, ignore_is_on_bcp, CHECK_(empty));
2510 } else {
2511 ResourceMark rm(THREAD);
2512 SignatureStream ss(signature, false);
2513 if (!ss.is_done()) {
2514 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2515 SignatureStream::NCDFError, CHECK_(empty));
2516 type = Handle(THREAD, mirror);
2517 ss.next();
2518 if (!ss.is_done()) type = Handle(); // error!
2519 }
2520 }
2521 if (type.is_null()) {
2522 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2523 }
2524
2525 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2526 JavaCallArguments args;
2527 args.push_oop(caller->java_mirror()); // the referring class
2528 args.push_int(ref_kind);
2529 args.push_oop(callee->java_mirror()); // the target class
2530 args.push_oop(name());
2531 args.push_oop(type());
2532 JavaValue result(T_OBJECT);
2533 JavaCalls::call_static(&result,
2534 SystemDictionary::MethodHandleNatives_klass(),
2535 vmSymbols::linkMethodHandleConstant_name(),
2536 vmSymbols::linkMethodHandleConstant_signature(),
2537 &args, CHECK_(empty));
2538 return Handle(THREAD, (oop) result.get_jobject());
2539 }
2540
2541 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2542 // name and signature, as interpreted relative to the given class loader.
2543 Handle SystemDictionary::make_dynamic_call_site(Handle bootstrap_method,
2544 Symbol* name,
2545 methodHandle signature_invoker,
2546 Handle info,
2547 methodHandle caller_method,
2548 int caller_bci,
2549 TRAPS) {
2550 Handle empty;
2551 guarantee(bootstrap_method.not_null() &&
2552 java_lang_invoke_MethodHandle::is_instance(bootstrap_method()),
2553 "caller must supply a valid BSM");
2554
2555 Handle caller_mname = MethodHandles::new_MemberName(CHECK_(empty));
2556 MethodHandles::init_MemberName(caller_mname(), caller_method());
2557
2558 // call java.lang.invoke.MethodHandleNatives::makeDynamicCallSite(bootm, name, mtype, info, caller_mname, caller_pos)
2559 oop name_str_oop = StringTable::intern(name, CHECK_(empty)); // not a handle!
2560 JavaCallArguments args(Handle(THREAD, bootstrap_method()));
2561 args.push_oop(name_str_oop);
2562 args.push_oop(signature_invoker->method_handle_type());
2563 args.push_oop(info());
2564 args.push_oop(caller_mname());
2565 args.push_int(caller_bci);
2566 JavaValue result(T_OBJECT);
2567 JavaCalls::call_static(&result,
2568 SystemDictionary::MethodHandleNatives_klass(),
2569 vmSymbols::makeDynamicCallSite_name(),
2570 vmSymbols::makeDynamicCallSite_signature(),
2571 &args, CHECK_(empty));
2572 oop call_site_oop = (oop) result.get_jobject();
2573 assert(call_site_oop->is_oop()
2574 /*&& java_lang_invoke_CallSite::is_instance(call_site_oop)*/, "must be sane");
2575 if (TraceMethodHandles) {
2576 #ifndef PRODUCT
2577 tty->print_cr("Linked invokedynamic bci=%d site="INTPTR_FORMAT":", caller_bci, call_site_oop);
2578 call_site_oop->print();
2579 tty->cr();
2580 #endif //PRODUCT
2581 }
2582 return call_site_oop;
2583 }
2584
2585 Handle SystemDictionary::find_bootstrap_method(methodHandle caller_method, int caller_bci,
2586 int cache_index,
2587 Handle& argument_info_result,
2588 TRAPS) {
2589 Handle empty;
2590
2591 constantPoolHandle pool;
2592 {
2593 klassOop caller = caller_method->method_holder();
2594 if (!Klass::cast(caller)->oop_is_instance()) return empty;
2595 pool = constantPoolHandle(THREAD, instanceKlass::cast(caller)->constants());
2596 }
2597
2598 int constant_pool_index = pool->cache()->entry_at(cache_index)->constant_pool_index();
2599 constantTag tag = pool->tag_at(constant_pool_index);
2600
2601 if (tag.is_invoke_dynamic()) {
2602 // JVM_CONSTANT_InvokeDynamic is an ordered pair of [bootm, name&type], plus optional arguments
2603 // The bootm, being a JVM_CONSTANT_MethodHandle, has its own cache entry.
2604 int bsm_index = pool->invoke_dynamic_bootstrap_method_ref_index_at(constant_pool_index);
2605 if (bsm_index != 0) {
2606 int bsm_index_in_cache = pool->cache()->entry_at(cache_index)->bootstrap_method_index_in_cache();
2607 DEBUG_ONLY(int bsm_index_2 = pool->cache()->entry_at(bsm_index_in_cache)->constant_pool_index());
2608 assert(bsm_index == bsm_index_2, "BSM constant lifted to cache");
2609 if (TraceMethodHandles) {
2610 tty->print_cr("resolving bootstrap method for "PTR_FORMAT" at %d at cache[%d]CP[%d]...",
2611 (intptr_t) caller_method(), caller_bci, cache_index, constant_pool_index);
2612 }
2613 oop bsm_oop = pool->resolve_cached_constant_at(bsm_index_in_cache, CHECK_(empty));
2614 if (TraceMethodHandles) {
2615 tty->print_cr("bootstrap method for "PTR_FORMAT" at %d retrieved as "PTR_FORMAT":",
2616 (intptr_t) caller_method(), caller_bci, (intptr_t) bsm_oop);
2617 }
2618 assert(bsm_oop->is_oop(), "must be sane");
2619 // caller must verify that it is of type MethodHandle
2620 Handle bsm(THREAD, bsm_oop);
2621 bsm_oop = NULL; // safety
2622
2623 // Extract the optional static arguments.
2624 Handle argument_info; // either null, or one arg, or Object[]{arg...}
2625 int argc = pool->invoke_dynamic_argument_count_at(constant_pool_index);
2626 if (TraceInvokeDynamic) {
2627 tty->print_cr("find_bootstrap_method: [%d/%d] CONSTANT_InvokeDynamic: %d[%d]",
2628 constant_pool_index, cache_index, bsm_index, argc);
2629 }
2630 if (argc > 0) {
2631 objArrayHandle arg_array;
2632 if (argc > 1) {
2633 objArrayOop arg_array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(), argc, CHECK_(empty));
2634 arg_array = objArrayHandle(THREAD, arg_array_oop);
2635 argument_info = arg_array;
2636 }
2637 for (int arg_i = 0; arg_i < argc; arg_i++) {
2638 int arg_index = pool->invoke_dynamic_argument_index_at(constant_pool_index, arg_i);
2639 oop arg_oop = pool->resolve_possibly_cached_constant_at(arg_index, CHECK_(empty));
2640 if (arg_array.is_null()) {
2641 argument_info = Handle(THREAD, arg_oop);
2642 } else {
2643 arg_array->obj_at_put(arg_i, arg_oop);
2644 }
2645 }
2646 }
2647
2648 argument_info_result = argument_info; // return argument_info to caller
2649 return bsm;
2650 }
2651 } else {
2652 ShouldNotReachHere(); // verifier does not allow this
2653 }
2654
2655 return empty;
2656 }
2657
2658 // Since the identity hash code for symbols changes when the symbols are
2659 // moved from the regular perm gen (hash in the mark word) to the shared
2660 // spaces (hash is the address), the classes loaded into the dictionary
2661 // may be in the wrong buckets.
2662
2663 void SystemDictionary::reorder_dictionary() {
2664 dictionary()->reorder_dictionary();
2665 }
2666
2667
2668 void SystemDictionary::copy_buckets(char** top, char* end) {
2669 dictionary()->copy_buckets(top, end);
2670 }
2671
2672
2673 void SystemDictionary::copy_table(char** top, char* end) {
2674 dictionary()->copy_table(top, end);
2675 }
2676
2677
2678 void SystemDictionary::reverse() {
2679 dictionary()->reverse();
2680 }
2681
2682 int SystemDictionary::number_of_classes() {
2683 return dictionary()->number_of_entries();
2684 }
2685
2686
2687 // ----------------------------------------------------------------------------
2688 #ifndef PRODUCT
2689
2690 void SystemDictionary::print() {
2691 dictionary()->print();
2692
2693 // Placeholders
2694 GCMutexLocker mu(SystemDictionary_lock);
2695 placeholders()->print();
2696
2697 // loader constraints - print under SD_lock
2698 constraints()->print();
2699 }
2700
2701 #endif
2702
2703 void SystemDictionary::verify() {
2704 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2705 guarantee(constraints() != NULL,
2706 "Verify of loader constraints failed");
2707 guarantee(dictionary()->number_of_entries() >= 0 &&
2708 placeholders()->number_of_entries() >= 0,
2709 "Verify of system dictionary failed");
2710
2711 // Verify dictionary
2712 dictionary()->verify();
2713
2714 GCMutexLocker mu(SystemDictionary_lock);
2715 placeholders()->verify();
2716
2717 // Verify constraint table
2718 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2719 constraints()->verify(dictionary(), placeholders());
2720 }
2721
2722
2723 void SystemDictionary::verify_obj_klass_present(Handle obj,
2724 Symbol* class_name,
2725 Handle class_loader) {
2726 GCMutexLocker mu(SystemDictionary_lock);
2727 Symbol* name;
2728
2729 klassOop probe = find_class(class_name, class_loader);
2730 if (probe == NULL) {
2731 probe = SystemDictionary::find_shared_class(class_name);
2732 if (probe == NULL) {
2733 name = find_placeholder(class_name, class_loader);
2734 }
2735 }
2736 guarantee(probe != NULL || name != NULL,
2737 "Loaded klasses should be in SystemDictionary");
2738 }
2739
2740 #ifndef PRODUCT
2741
2742 // statistics code
2743 class ClassStatistics: AllStatic {
2744 private:
2745 static int nclasses; // number of classes
2746 static int nmethods; // number of methods
2747 static int nmethoddata; // number of methodData
2748 static int class_size; // size of class objects in words
2749 static int method_size; // size of method objects in words
2750 static int debug_size; // size of debug info in methods
2751 static int methoddata_size; // size of methodData objects in words
2752
2753 static void do_class(klassOop k) {
2754 nclasses++;
2755 class_size += k->size();
2756 if (k->klass_part()->oop_is_instance()) {
2757 instanceKlass* ik = (instanceKlass*)k->klass_part();
2758 class_size += ik->methods()->size();
2759 class_size += ik->constants()->size();
2760 class_size += ik->local_interfaces()->size();
2761 class_size += ik->transitive_interfaces()->size();
2762 // We do not have to count implementors, since we only store one!
2763 class_size += ik->all_fields_count() * FieldInfo::field_slots;
2764 }
2765 }
2766
2767 static void do_method(methodOop m) {
2768 nmethods++;
2769 method_size += m->size();
2770 // class loader uses same objArray for empty vectors, so don't count these
2771 if (m->has_stackmap_table()) {
2772 method_size += m->stackmap_data()->size();
2773 }
2774
2775 methodDataOop mdo = m->method_data();
2776 if (mdo != NULL) {
2777 nmethoddata++;
2778 methoddata_size += mdo->size();
2779 }
2780 }
2781
2782 public:
2783 static void print() {
2784 SystemDictionary::classes_do(do_class);
2785 SystemDictionary::methods_do(do_method);
2786 tty->print_cr("Class statistics:");
2787 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2788 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2789 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2790 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2791 }
2792 };
2793
2794
2795 int ClassStatistics::nclasses = 0;
2796 int ClassStatistics::nmethods = 0;
2797 int ClassStatistics::nmethoddata = 0;
2798 int ClassStatistics::class_size = 0;
2799 int ClassStatistics::method_size = 0;
2800 int ClassStatistics::debug_size = 0;
2801 int ClassStatistics::methoddata_size = 0;
2802
2803 void SystemDictionary::print_class_statistics() {
2804 ResourceMark rm;
2805 ClassStatistics::print();
2806 }
2807
2808
2809 class MethodStatistics: AllStatic {
2810 public:
2811 enum {
2812 max_parameter_size = 10
2813 };
2814 private:
2815
2816 static int _number_of_methods;
2817 static int _number_of_final_methods;
2818 static int _number_of_static_methods;
2819 static int _number_of_native_methods;
2820 static int _number_of_synchronized_methods;
2821 static int _number_of_profiled_methods;
2822 static int _number_of_bytecodes;
2823 static int _parameter_size_profile[max_parameter_size];
2824 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2825
2826 static void initialize() {
2827 _number_of_methods = 0;
2828 _number_of_final_methods = 0;
2829 _number_of_static_methods = 0;
2830 _number_of_native_methods = 0;
2831 _number_of_synchronized_methods = 0;
2832 _number_of_profiled_methods = 0;
2833 _number_of_bytecodes = 0;
2834 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2835 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2836 };
2837
2838 static void do_method(methodOop m) {
2839 _number_of_methods++;
2840 // collect flag info
2841 if (m->is_final() ) _number_of_final_methods++;
2842 if (m->is_static() ) _number_of_static_methods++;
2843 if (m->is_native() ) _number_of_native_methods++;
2844 if (m->is_synchronized()) _number_of_synchronized_methods++;
2845 if (m->method_data() != NULL) _number_of_profiled_methods++;
2846 // collect parameter size info (add one for receiver, if any)
2847 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2848 // collect bytecodes info
2849 {
2850 Thread *thread = Thread::current();
2851 HandleMark hm(thread);
2852 BytecodeStream s(methodHandle(thread, m));
2853 Bytecodes::Code c;
2854 while ((c = s.next()) >= 0) {
2855 _number_of_bytecodes++;
2856 _bytecodes_profile[c]++;
2857 }
2858 }
2859 }
2860
2861 public:
2862 static void print() {
2863 initialize();
2864 SystemDictionary::methods_do(do_method);
2865 // generate output
2866 tty->cr();
2867 tty->print_cr("Method statistics (static):");
2868 // flag distribution
2869 tty->cr();
2870 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2871 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2872 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2873 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2874 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2875 // parameter size profile
2876 tty->cr();
2877 { int tot = 0;
2878 int avg = 0;
2879 for (int i = 0; i < max_parameter_size; i++) {
2880 int n = _parameter_size_profile[i];
2881 tot += n;
2882 avg += n*i;
2883 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2884 }
2885 assert(tot == _number_of_methods, "should be the same");
2886 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2887 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2888 }
2889 // bytecodes profile
2890 tty->cr();
2891 { int tot = 0;
2892 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2893 if (Bytecodes::is_defined(i)) {
2894 Bytecodes::Code c = Bytecodes::cast(i);
2895 int n = _bytecodes_profile[c];
2896 tot += n;
2897 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2898 }
2899 }
2900 assert(tot == _number_of_bytecodes, "should be the same");
2901 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2902 }
2903 tty->cr();
2904 }
2905 };
2906
2907 int MethodStatistics::_number_of_methods;
2908 int MethodStatistics::_number_of_final_methods;
2909 int MethodStatistics::_number_of_static_methods;
2910 int MethodStatistics::_number_of_native_methods;
2911 int MethodStatistics::_number_of_synchronized_methods;
2912 int MethodStatistics::_number_of_profiled_methods;
2913 int MethodStatistics::_number_of_bytecodes;
2914 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2915 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2916
2917
2918 void SystemDictionary::print_method_statistics() {
2919 MethodStatistics::print();
2920 }
2921
2922 #endif // PRODUCT