1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/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 "compiler/compileBroker.hpp"
34 #include "interpreter/bytecodeStream.hpp"
35 #include "interpreter/interpreter.hpp"
36 #include "memory/gcLocker.hpp"
37 #include "memory/oopFactory.hpp"
38 #include "oops/instanceKlass.hpp"
39 #include "oops/instanceRefKlass.hpp"
40 #include "oops/klass.inline.hpp"
41 #include "oops/methodDataOop.hpp"
42 #include "oops/objArrayKlass.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/oop.inline2.hpp"
45 #include "oops/typeArrayKlass.hpp"
46 #include "prims/jvmtiEnvBase.hpp"
47 #include "prims/methodHandles.hpp"
48 #include "runtime/biasedLocking.hpp"
49 #include "runtime/fieldType.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/java.hpp"
52 #include "runtime/javaCalls.hpp"
53 #include "runtime/mutexLocker.hpp"
54 #include "runtime/signature.hpp"
55 #include "services/classLoadingService.hpp"
56 #include "services/threadService.hpp"
57
58 #if INCLUDE_TRACE
59 #include "memory/iterator.hpp"
60 #include "trace/tracing.hpp"
61 #include "trace/traceMacros.hpp"
62 #endif
63
64
65 Dictionary* SystemDictionary::_dictionary = NULL;
66 PlaceholderTable* SystemDictionary::_placeholders = NULL;
67 Dictionary* SystemDictionary::_shared_dictionary = NULL;
68 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
69 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
70 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
71
72
73 int SystemDictionary::_number_of_modifications = 0;
74 int SystemDictionary::_sdgeneration = 0;
75 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
76 20201,40423,99991};
77
78 oop SystemDictionary::_system_loader_lock_obj = NULL;
79
80 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
81 = { NULL /*, NULL...*/ };
82
83 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
84
85 oop SystemDictionary::_java_system_loader = NULL;
86
87 bool SystemDictionary::_has_loadClassInternal = false;
88 bool SystemDictionary::_has_checkPackageAccess = false;
89
90 // lazily initialized klass variables
91 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
92
93
94 // ----------------------------------------------------------------------------
95 // Java-level SystemLoader
96
97 oop SystemDictionary::java_system_loader() {
98 return _java_system_loader;
99 }
100
101 void SystemDictionary::compute_java_system_loader(TRAPS) {
102 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
103 JavaValue result(T_OBJECT);
104 JavaCalls::call_static(&result,
105 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
106 vmSymbols::getSystemClassLoader_name(),
107 vmSymbols::void_classloader_signature(),
108 CHECK);
109
110 _java_system_loader = (oop)result.get_jobject();
111 }
112
113
114 // ----------------------------------------------------------------------------
115 // debugging
116
117 #ifdef ASSERT
118
119 // return true if class_name contains no '.' (internal format is '/')
120 bool SystemDictionary::is_internal_format(Symbol* class_name) {
121 if (class_name != NULL) {
122 ResourceMark rm;
123 char* name = class_name->as_C_string();
124 return strchr(name, '.') == NULL;
125 } else {
126 return true;
127 }
128 }
129
130 #endif
131
132 // ----------------------------------------------------------------------------
133 // Parallel class loading check
134
135 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
136 if (UnsyncloadClass || class_loader.is_null()) return true;
137 if (AlwaysLockClassLoader) return false;
138 return java_lang_ClassLoader::parallelCapable(class_loader());
139 }
140 // ----------------------------------------------------------------------------
141 // ParallelDefineClass flag does not apply to bootclass loader
142 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
143 if (class_loader.is_null()) return false;
144 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
145 return true;
146 }
147 return false;
148 }
149 // ----------------------------------------------------------------------------
150 // Resolving of classes
151
152 // Forwards to resolve_or_null
153
154 klassOop SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
155 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
156 if (HAS_PENDING_EXCEPTION || klass == NULL) {
157 KlassHandle k_h(THREAD, klass);
158 // can return a null klass
159 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
160 }
161 return klass;
162 }
163
164 klassOop SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
165 if (HAS_PENDING_EXCEPTION) {
166 // If we have a pending exception we forward it to the caller, unless throw_error is true,
167 // in which case we have to check whether the pending exception is a ClassNotFoundException,
168 // and if so convert it to a NoClassDefFoundError
169 // And chain the original ClassNotFoundException
170 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
171 ResourceMark rm(THREAD);
172 assert(klass_h() == NULL, "Should not have result with exception pending");
173 Handle e(THREAD, PENDING_EXCEPTION);
174 CLEAR_PENDING_EXCEPTION;
175 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
176 } else {
177 return NULL;
178 }
179 }
180 // Class not found, throw appropriate error or exception depending on value of throw_error
181 if (klass_h() == NULL) {
182 ResourceMark rm(THREAD);
183 if (throw_error) {
184 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
185 } else {
186 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
187 }
188 }
189 return (klassOop)klass_h();
190 }
191
192
193 klassOop SystemDictionary::resolve_or_fail(Symbol* class_name,
194 bool throw_error, TRAPS)
195 {
196 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
197 }
198
199
200 // Forwards to resolve_instance_class_or_null
201
202 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
203 assert(!THREAD->is_Compiler_thread(),
204 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
205 class_name->as_C_string(),
206 class_loader.is_null() ? "null" : class_loader->klass()->klass_part()->name()->as_C_string()));
207 if (FieldType::is_array(class_name)) {
208 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
209 } else if (FieldType::is_obj(class_name)) {
210 ResourceMark rm(THREAD);
211 // Ignore wrapping L and ;.
212 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
213 class_name->utf8_length() - 2, CHECK_NULL);
214 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
215 } else {
216 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
217 }
218 }
219
220 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
221 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
222 }
223
224 // Forwards to resolve_instance_class_or_null
225
226 klassOop SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
227 Handle class_loader,
228 Handle protection_domain,
229 TRAPS) {
230 assert(FieldType::is_array(class_name), "must be array");
231 klassOop k = NULL;
232 FieldArrayInfo fd;
233 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
234 // of this call
235 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
236 if (t == T_OBJECT) {
237 // naked oop "k" is OK here -- we assign back into it
238 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
239 class_loader,
240 protection_domain,
241 CHECK_NULL);
242 if (k != NULL) {
243 k = Klass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
244 }
245 } else {
246 k = Universe::typeArrayKlassObj(t);
247 k = typeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
248 }
249 return k;
250 }
251
252
253 // Must be called for any super-class or super-interface resolution
254 // during class definition to allow class circularity checking
255 // super-interface callers:
256 // parse_interfaces - for defineClass & jvmtiRedefineClasses
257 // super-class callers:
258 // ClassFileParser - for defineClass & jvmtiRedefineClasses
259 // load_shared_class - while loading a class from shared archive
260 // resolve_instance_class_or_null:
261 // via: handle_parallel_super_load
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 klassOop SystemDictionary::resolve_super_or_fail(Symbol* child_name,
289 Symbol* class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
294 // Double-check, if child class is already loaded, just return super-class,interface
295 // Don't add a placedholder if already loaded, i.e. already in system dictionary
296 // Make sure there's a placeholder for the *child* before resolving.
297 // Used as a claim that this thread is currently loading superclass/classloader
298 // Used here for ClassCircularity checks and also for heap verification
299 // (every instanceKlass in the heap needs to be in the system dictionary
300 // or have a placeholder).
301 // Must check ClassCircularity before checking if super class is already loaded
302 //
303 // We might not already have a placeholder if this child_name was
304 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
305 // the name of the class might not be known until the stream is actually
306 // parsed.
307 // Bugs 4643874, 4715493
308 // compute_hash can have a safepoint
309
310 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 jlong class_load_start_time = class_load_tracing_begin();
590
591 // UseNewReflection
592 // Fix for 4474172; see evaluation for more details
593 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
594
595 // Do lookup to see if class already exist and the protection domain
596 // has the right access
597 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
598 int d_index = dictionary()->hash_to_index(d_hash);
599 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
600 protection_domain, THREAD);
601 if (probe != NULL) return probe;
602
603
604 // Non-bootstrap class loaders will call out to class loader and
605 // define via jvm/jni_DefineClass which will acquire the
606 // class loader object lock to protect against multiple threads
607 // defining the class in parallel by accident.
608 // This lock must be acquired here so the waiter will find
609 // any successful result in the SystemDictionary and not attempt
610 // the define
611 // ParallelCapable Classloaders and the bootstrap classloader,
612 // or all classloaders with UnsyncloadClass do not acquire lock here
613 bool DoObjectLock = true;
614 if (is_parallelCapable(class_loader)) {
615 DoObjectLock = false;
616 }
617
618 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
619 int p_index = placeholders()->hash_to_index(p_hash);
620
621 // Class is not in SystemDictionary so we have to do loading.
622 // Make sure we are synchronized on the class loader before we proceed
623 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
624 check_loader_lock_contention(lockObject, THREAD);
625 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
626
627 // Check again (after locking) if class already exist in SystemDictionary
628 bool class_has_been_loaded = false;
629 bool super_load_in_progress = false;
630 bool havesupername = false;
631 instanceKlassHandle k;
632 PlaceholderEntry* placeholder;
633 Symbol* superclassname = NULL;
634
635 {
636 MutexLocker mu(SystemDictionary_lock, THREAD);
637 klassOop check = find_class(d_index, d_hash, name, class_loader);
638 if (check != NULL) {
639 // Klass is already loaded, so just return it
640 class_has_been_loaded = true;
641 k = instanceKlassHandle(THREAD, check);
642 } else {
643 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
644 if (placeholder && placeholder->super_load_in_progress()) {
645 super_load_in_progress = true;
646 if (placeholder->havesupername() == true) {
647 superclassname = placeholder->supername();
648 havesupername = true;
649 }
650 }
651 }
652 }
653
654 // If the class in is in the placeholder table, class loading is in progress
655 if (super_load_in_progress && havesupername==true) {
656 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
657 class_loader, protection_domain, lockObject, THREAD);
658 if (HAS_PENDING_EXCEPTION) {
659 return NULL;
660 }
661 if (!k.is_null()) {
662 class_has_been_loaded = true;
663 }
664 }
665
666 if (!class_has_been_loaded) {
667
668 // add placeholder entry to record loading instance class
669 // Five cases:
670 // All cases need to prevent modifying bootclasssearchpath
671 // in parallel with a classload of same classname
672 // Redefineclasses uses existence of the placeholder for the duration
673 // of the class load to prevent concurrent redefinition of not completely
674 // defined classes.
675 // case 1. traditional classloaders that rely on the classloader object lock
676 // - no other need for LOAD_INSTANCE
677 // case 2. traditional classloaders that break the classloader object lock
678 // as a deadlock workaround. Detection of this case requires that
679 // this check is done while holding the classloader object lock,
680 // and that lock is still held when calling classloader's loadClass.
681 // For these classloaders, we ensure that the first requestor
682 // completes the load and other requestors wait for completion.
683 // case 3. UnsyncloadClass - don't use objectLocker
684 // With this flag, we allow parallel classloading of a
685 // class/classloader pair
686 // case4. Bootstrap classloader - don't own objectLocker
687 // This classloader supports parallelism at the classloader level,
688 // but only allows a single load of a class/classloader pair.
689 // No performance benefit and no deadlock issues.
690 // case 5. parallelCapable user level classloaders - without objectLocker
691 // Allow parallel classloading of a class/classloader pair
692 bool throw_circularity_error = false;
693 {
694 MutexLocker mu(SystemDictionary_lock, THREAD);
695 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
696 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
697 if (oldprobe) {
698 // only need check_seen_thread once, not on each loop
699 // 6341374 java/lang/Instrument with -Xcomp
700 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
701 throw_circularity_error = true;
702 } else {
703 // case 1: traditional: should never see load_in_progress.
704 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
705
706 // case 4: bootstrap classloader: prevent futile classloading,
707 // wait on first requestor
708 if (class_loader.is_null()) {
709 SystemDictionary_lock->wait();
710 } else {
711 // case 2: traditional with broken classloader lock. wait on first
712 // requestor.
713 double_lock_wait(lockObject, THREAD);
714 }
715 // Check if classloading completed while we were waiting
716 klassOop check = find_class(d_index, d_hash, name, class_loader);
717 if (check != NULL) {
718 // Klass is already loaded, so just return it
719 k = instanceKlassHandle(THREAD, check);
720 class_has_been_loaded = true;
721 }
722 // check if other thread failed to load and cleaned up
723 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
724 }
725 }
726 }
727 }
728 // All cases: add LOAD_INSTANCE
729 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
730 // LOAD_INSTANCE in parallel
731 // add placeholder entry even if error - callers will remove on error
732 if (!throw_circularity_error && !class_has_been_loaded) {
733 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
734 // For class loaders that do not acquire the classloader object lock,
735 // if they did not catch another thread holding LOAD_INSTANCE,
736 // need a check analogous to the acquire ObjectLocker/find_class
737 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
738 // one final check if the load has already completed
739 // class loaders holding the ObjectLock shouldn't find the class here
740 klassOop check = find_class(d_index, d_hash, name, class_loader);
741 if (check != NULL) {
742 // Klass is already loaded, so just return it
743 k = instanceKlassHandle(THREAD, check);
744 class_has_been_loaded = true;
745 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
746 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
747 SystemDictionary_lock->notify_all();
748 }
749 }
750 }
751 // must throw error outside of owning lock
752 if (throw_circularity_error) {
753 ResourceMark rm(THREAD);
754 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
755 }
756
757 if (!class_has_been_loaded) {
758
759 // Do actual loading
760 k = load_instance_class(name, class_loader, THREAD);
761
762 // For UnsyncloadClass only
763 // If they got a linkageError, check if a parallel class load succeeded.
764 // If it did, then for bytecode resolution the specification requires
765 // that we return the same result we did for the other thread, i.e. the
766 // successfully loaded instanceKlass
767 // Should not get here for classloaders that support parallelism
768 // with the new cleaner mechanism, even with AllowParallelDefineClass
769 // Bootstrap goes through here to allow for an extra guarantee check
770 if (UnsyncloadClass || (class_loader.is_null())) {
771 if (k.is_null() && HAS_PENDING_EXCEPTION
772 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
773 MutexLocker mu(SystemDictionary_lock, THREAD);
774 klassOop check = find_class(d_index, d_hash, name, class_loader);
775 if (check != NULL) {
776 // Klass is already loaded, so just use it
777 k = instanceKlassHandle(THREAD, check);
778 CLEAR_PENDING_EXCEPTION;
779 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
780 }
781 }
782 }
783
784 // clean up placeholder entries for success or error
785 // This cleans up LOAD_INSTANCE entries
786 // It also cleans up LOAD_SUPER entries on errors from
787 // calling load_instance_class
788 {
789 MutexLocker mu(SystemDictionary_lock, THREAD);
790 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
791 if (probe != NULL) {
792 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
793 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
794 SystemDictionary_lock->notify_all();
795 }
796 }
797
798 // If everything was OK (no exceptions, no null return value)
799 if (!HAS_PENDING_EXCEPTION && !k.is_null()) {
800 post_class_load_event(class_load_start_time, k, class_loader);
801
802 // class_loader is NOT the defining loader, do a little more bookkeeping.
803 if (k->class_loader() != class_loader()) {
804 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
805
806 // Need to check for a PENDING_EXCEPTION again; check_constraints
807 // can throw and doesn't use the CHECK macro.
808 if (!HAS_PENDING_EXCEPTION) {
809 { // Grabbing the Compile_lock prevents systemDictionary updates
810 // during compilations.
811 MutexLocker mu(Compile_lock, THREAD);
812 update_dictionary(d_index, d_hash, p_index, p_hash,
813 k, class_loader, THREAD);
814 }
815
816 if (JvmtiExport::should_post_class_load()) {
817 Thread *thread = THREAD;
818 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
819 JvmtiExport::post_class_load((JavaThread *) thread, k());
820 }
821 }
822 }
823 }
824 if (HAS_PENDING_EXCEPTION || k.is_null()) {
825 // On error, clean up placeholders
826 {
827 MutexLocker mu(SystemDictionary_lock, THREAD);
828 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
829 SystemDictionary_lock->notify_all();
830 }
831 return NULL;
832 }
833 }
834 }
835
836 #ifdef ASSERT
837 {
838 Handle loader (THREAD, k->class_loader());
839 MutexLocker mu(SystemDictionary_lock, THREAD);
840 oop kk = find_class(name, loader);
841 assert(kk == k(), "should be present in dictionary");
842 }
843 #endif
844
845 // return if the protection domain in NULL
846 if (protection_domain() == NULL) return k();
847
848 // Check the protection domain has the right access
849 {
850 MutexLocker mu(SystemDictionary_lock, THREAD);
851 // Note that we have an entry, and entries can be deleted only during GC,
852 // so we cannot allow GC to occur while we're holding this entry.
853 // We're using a No_Safepoint_Verifier to catch any place where we
854 // might potentially do a GC at all.
855 // SystemDictionary::do_unloading() asserts that classes are only
856 // unloaded at a safepoint.
857 No_Safepoint_Verifier nosafepoint;
858 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
859 class_loader,
860 protection_domain)) {
861 return k();
862 }
863 }
864
865 // Verify protection domain. If it fails an exception is thrown
866 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
867
868 return k();
869 }
870
871
872 // This routine does not lock the system dictionary.
873 //
874 // Since readers don't hold a lock, we must make sure that system
875 // dictionary entries are only removed at a safepoint (when only one
876 // thread is running), and are added to in a safe way (all links must
877 // be updated in an MT-safe manner).
878 //
879 // Callers should be aware that an entry could be added just after
880 // _dictionary->bucket(index) is read here, so the caller will not see
881 // the new entry.
882
883 klassOop SystemDictionary::find(Symbol* class_name,
884 Handle class_loader,
885 Handle protection_domain,
886 TRAPS) {
887
888 // UseNewReflection
889 // The result of this call should be consistent with the result
890 // of the call to resolve_instance_class_or_null().
891 // See evaluation 6790209 and 4474172 for more details.
892 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
893
894 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
895 int d_index = dictionary()->hash_to_index(d_hash);
896
897 {
898 // Note that we have an entry, and entries can be deleted only during GC,
899 // so we cannot allow GC to occur while we're holding this entry.
900 // We're using a No_Safepoint_Verifier to catch any place where we
901 // might potentially do a GC at all.
902 // SystemDictionary::do_unloading() asserts that classes are only
903 // unloaded at a safepoint.
904 No_Safepoint_Verifier nosafepoint;
905 return dictionary()->find(d_index, d_hash, class_name, class_loader,
906 protection_domain, THREAD);
907 }
908 }
909
910
911 // Look for a loaded instance or array klass by name. Do not do any loading.
912 // return NULL in case of error.
913 klassOop SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
914 Handle class_loader,
915 Handle protection_domain,
916 TRAPS) {
917 klassOop k = NULL;
918 assert(class_name != NULL, "class name must be non NULL");
919
920 if (FieldType::is_array(class_name)) {
921 // The name refers to an array. Parse the name.
922 // dimension and object_key in FieldArrayInfo are assigned as a
923 // side-effect of this call
924 FieldArrayInfo fd;
925 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
926 if (t != T_OBJECT) {
927 k = Universe::typeArrayKlassObj(t);
928 } else {
929 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
930 }
931 if (k != NULL) {
932 k = Klass::cast(k)->array_klass_or_null(fd.dimension());
933 }
934 } else {
935 k = find(class_name, class_loader, protection_domain, THREAD);
936 }
937 return k;
938 }
939
940 // Note: this method is much like resolve_from_stream, but
941 // updates no supplemental data structures.
942 // TODO consolidate the two methods with a helper routine?
943 klassOop SystemDictionary::parse_stream(Symbol* class_name,
944 Handle class_loader,
945 Handle protection_domain,
946 ClassFileStream* st,
947 KlassHandle host_klass,
948 GrowableArray<Handle>* cp_patches,
949 TRAPS) {
950 TempNewSymbol parsed_name = NULL;
951
952 jlong class_load_start_time = class_load_tracing_begin();
953
954 // Parse the stream. Note that we do this even though this klass might
955 // already be present in the SystemDictionary, otherwise we would not
956 // throw potential ClassFormatErrors.
957 //
958 // Note: "name" is updated.
959 // Further note: a placeholder will be added for this class when
960 // super classes are loaded (resolve_super_or_fail). We expect this
961 // to be called for all classes but java.lang.Object; and we preload
962 // java.lang.Object through resolve_or_fail, not this path.
963
964 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
965 class_loader,
966 protection_domain,
967 host_klass,
968 cp_patches,
969 parsed_name,
970 true,
971 THREAD);
972
973 // We don't redefine the class, so we just need to clean up whether there
974 // was an error or not (don't want to modify any system dictionary
975 // data structures).
976 // Parsed name could be null if we threw an error before we got far
977 // enough along to parse it -- in that case, there is nothing to clean up.
978 if (parsed_name != NULL) {
979 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
980 class_loader);
981 int p_index = placeholders()->hash_to_index(p_hash);
982 {
983 MutexLocker mu(SystemDictionary_lock, THREAD);
984 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
985 SystemDictionary_lock->notify_all();
986 }
987 }
988
989 if (host_klass.not_null() && k.not_null()) {
990 assert(EnableInvokeDynamic, "");
991 // If it's anonymous, initialize it now, since nobody else will.
992 k->set_host_klass(host_klass());
993
994 {
995 MutexLocker mu_r(Compile_lock, THREAD);
996
997 // Add to class hierarchy, initialize vtables, and do possible
998 // deoptimizations.
999 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1000
1001 // But, do not add to system dictionary.
1002 }
1003
1004 k->eager_initialize(THREAD);
1005
1006 post_class_load_event(class_load_start_time, k, class_loader);
1007
1008 // notify jvmti
1009 if (JvmtiExport::should_post_class_load()) {
1010 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1011 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1012 }
1013 }
1014
1015 return k();
1016 }
1017
1018 // Add a klass to the system from a stream (called by jni_DefineClass and
1019 // JVM_DefineClass).
1020 // Note: class_name can be NULL. In that case we do not know the name of
1021 // the class until we have parsed the stream.
1022
1023 klassOop SystemDictionary::resolve_from_stream(Symbol* class_name,
1024 Handle class_loader,
1025 Handle protection_domain,
1026 ClassFileStream* st,
1027 bool verify,
1028 TRAPS) {
1029
1030 // Classloaders that support parallelism, e.g. bootstrap classloader,
1031 // or all classloaders with UnsyncloadClass do not acquire lock here
1032 bool DoObjectLock = true;
1033 if (is_parallelCapable(class_loader)) {
1034 DoObjectLock = false;
1035 }
1036
1037 // Make sure we are synchronized on the class loader before we proceed
1038 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1039 check_loader_lock_contention(lockObject, THREAD);
1040 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1041
1042 TempNewSymbol parsed_name = NULL;
1043
1044 // Parse the stream. Note that we do this even though this klass might
1045 // already be present in the SystemDictionary, otherwise we would not
1046 // throw potential ClassFormatErrors.
1047 //
1048 // Note: "name" is updated.
1049 // Further note: a placeholder will be added for this class when
1050 // super classes are loaded (resolve_super_or_fail). We expect this
1051 // to be called for all classes but java.lang.Object; and we preload
1052 // java.lang.Object through resolve_or_fail, not this path.
1053
1054 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1055 class_loader,
1056 protection_domain,
1057 parsed_name,
1058 verify,
1059 THREAD);
1060
1061 const char* pkg = "java/";
1062 if (!HAS_PENDING_EXCEPTION &&
1063 !class_loader.is_null() &&
1064 parsed_name != NULL &&
1065 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1066 // It is illegal to define classes in the "java." package from
1067 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1068 ResourceMark rm(THREAD);
1069 char* name = parsed_name->as_C_string();
1070 char* index = strrchr(name, '/');
1071 *index = '\0'; // chop to just the package name
1072 while ((index = strchr(name, '/')) != NULL) {
1073 *index = '.'; // replace '/' with '.' in package name
1074 }
1075 const char* fmt = "Prohibited package name: %s";
1076 size_t len = strlen(fmt) + strlen(name);
1077 char* message = NEW_RESOURCE_ARRAY(char, len);
1078 jio_snprintf(message, len, fmt, name);
1079 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1080 vmSymbols::java_lang_SecurityException(), message);
1081 }
1082
1083 if (!HAS_PENDING_EXCEPTION) {
1084 assert(parsed_name != NULL, "Sanity");
1085 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1086 // Verification prevents us from creating names with dots in them, this
1087 // asserts that that's the case.
1088 assert(is_internal_format(parsed_name),
1089 "external class name format used internally");
1090
1091 // Add class just loaded
1092 // If a class loader supports parallel classloading handle parallel define requests
1093 // find_or_define_instance_class may return a different instanceKlass
1094 if (is_parallelCapable(class_loader)) {
1095 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1096 } else {
1097 define_instance_class(k, THREAD);
1098 }
1099 }
1100
1101 // If parsing the class file or define_instance_class failed, we
1102 // need to remove the placeholder added on our behalf. But we
1103 // must make sure parsed_name is valid first (it won't be if we had
1104 // a format error before the class was parsed far enough to
1105 // find the name).
1106 if (HAS_PENDING_EXCEPTION && parsed_name != NULL) {
1107 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1108 class_loader);
1109 int p_index = placeholders()->hash_to_index(p_hash);
1110 {
1111 MutexLocker mu(SystemDictionary_lock, THREAD);
1112 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1113 SystemDictionary_lock->notify_all();
1114 }
1115 return NULL;
1116 }
1117
1118 // Make sure that we didn't leave a place holder in the
1119 // SystemDictionary; this is only done on success
1120 debug_only( {
1121 if (!HAS_PENDING_EXCEPTION) {
1122 assert(parsed_name != NULL, "parsed_name is still null?");
1123 Symbol* h_name = k->name();
1124 Handle h_loader (THREAD, k->class_loader());
1125
1126 MutexLocker mu(SystemDictionary_lock, THREAD);
1127
1128 klassOop check = find_class(parsed_name, class_loader);
1129 assert(check == k(), "should be present in the dictionary");
1130
1131 klassOop check2 = find_class(h_name, h_loader);
1132 assert(check == check2, "name inconsistancy in SystemDictionary");
1133 }
1134 } );
1135
1136 return k();
1137 }
1138
1139
1140 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1141 int number_of_entries) {
1142 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1143 "bad shared dictionary size.");
1144 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1145 }
1146
1147
1148 // If there is a shared dictionary, then find the entry for the
1149 // given shared system class, if any.
1150
1151 klassOop SystemDictionary::find_shared_class(Symbol* class_name) {
1152 if (shared_dictionary() != NULL) {
1153 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, Handle());
1154 int d_index = shared_dictionary()->hash_to_index(d_hash);
1155 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1156 } else {
1157 return NULL;
1158 }
1159 }
1160
1161
1162 // Load a class from the shared spaces (found through the shared system
1163 // dictionary). Force the superclass and all interfaces to be loaded.
1164 // Update the class definition to include sibling classes and no
1165 // subclasses (yet). [Classes in the shared space are not part of the
1166 // object hierarchy until loaded.]
1167
1168 instanceKlassHandle SystemDictionary::load_shared_class(
1169 Symbol* class_name, Handle class_loader, TRAPS) {
1170 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1171 return load_shared_class(ik, class_loader, THREAD);
1172 }
1173
1174 // Note well! Changes to this method may affect oop access order
1175 // in the shared archive. Please take care to not make changes that
1176 // adversely affect cold start time by changing the oop access order
1177 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1178 // MarkAndMoveOrderedReadWrite closures.
1179 instanceKlassHandle SystemDictionary::load_shared_class(
1180 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1181 assert(class_loader.is_null(), "non-null classloader for shared class?");
1182 if (ik.not_null()) {
1183 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1184 Symbol* class_name = ik->name();
1185
1186 // Found the class, now load the superclass and interfaces. If they
1187 // are shared, add them to the main system dictionary and reset
1188 // their hierarchy references (supers, subs, and interfaces).
1189
1190 if (ik->super() != NULL) {
1191 Symbol* cn = ik->super()->klass_part()->name();
1192 resolve_super_or_fail(class_name, cn,
1193 class_loader, Handle(), true, CHECK_(nh));
1194 }
1195
1196 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1197 int num_interfaces = interfaces->length();
1198 for (int index = 0; index < num_interfaces; index++) {
1199 klassOop k = klassOop(interfaces->obj_at(index));
1200
1201 // Note: can not use instanceKlass::cast here because
1202 // interfaces' instanceKlass's C++ vtbls haven't been
1203 // reinitialized yet (they will be once the interface classes
1204 // are loaded)
1205 Symbol* name = k->klass_part()->name();
1206 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1207 }
1208
1209 // Adjust methods to recover missing data. They need addresses for
1210 // interpreter entry points and their default native method address
1211 // must be reset.
1212
1213 // Updating methods must be done under a lock so multiple
1214 // threads don't update these in parallel
1215 // Shared classes are all currently loaded by the bootstrap
1216 // classloader, so this will never cause a deadlock on
1217 // a custom class loader lock.
1218
1219 {
1220 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1221 check_loader_lock_contention(lockObject, THREAD);
1222 ObjectLocker ol(lockObject, THREAD, true);
1223
1224 objArrayHandle methods (THREAD, ik->methods());
1225 int num_methods = methods->length();
1226 for (int index2 = 0; index2 < num_methods; ++index2) {
1227 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1228 m()->link_method(m, CHECK_(nh));
1229 }
1230 if (JvmtiExport::has_redefined_a_class()) {
1231 // Reinitialize vtable because RedefineClasses may have changed some
1232 // entries in this vtable for super classes so the CDS vtable might
1233 // point to old or obsolete entries. RedefineClasses doesn't fix up
1234 // vtables in the shared system dictionary, only the main one.
1235 // It also redefines the itable too so fix that too.
1236 ResourceMark rm(THREAD);
1237 ik->vtable()->initialize_vtable(false, CHECK_(nh));
1238 ik->itable()->initialize_itable(false, CHECK_(nh));
1239 }
1240 }
1241
1242 if (TraceClassLoading) {
1243 ResourceMark rm;
1244 tty->print("[Loaded %s", ik->external_name());
1245 tty->print(" from shared objects file");
1246 tty->print_cr("]");
1247 }
1248 // notify a class loaded from shared object
1249 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1250 true /* shared class */);
1251 }
1252 return ik;
1253 }
1254
1255
1256 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1257 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1258 if (class_loader.is_null()) {
1259
1260 // Search the shared system dictionary for classes preloaded into the
1261 // shared spaces.
1262 instanceKlassHandle k;
1263 {
1264 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1265 k = load_shared_class(class_name, class_loader, THREAD);
1266 }
1267
1268 if (k.is_null()) {
1269 // Use VM class loader
1270 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1271 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1272 }
1273
1274 // find_or_define_instance_class may return a different instanceKlass
1275 if (!k.is_null()) {
1276 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1277 }
1278 return k;
1279 } else {
1280 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1281 ResourceMark rm(THREAD);
1282
1283 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1284 JavaThread* jt = (JavaThread*) THREAD;
1285
1286 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1287 ClassLoader::perf_app_classload_selftime(),
1288 ClassLoader::perf_app_classload_count(),
1289 jt->get_thread_stat()->perf_recursion_counts_addr(),
1290 jt->get_thread_stat()->perf_timers_addr(),
1291 PerfClassTraceTime::CLASS_LOAD);
1292
1293 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1294 // Translate to external class name format, i.e., convert '/' chars to '.'
1295 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1296
1297 JavaValue result(T_OBJECT);
1298
1299 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1300
1301 // Call public unsynchronized loadClass(String) directly for all class loaders
1302 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1303 // acquire a class-name based lock rather than the class loader object lock.
1304 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1305 // so the call to loadClassInternal() was not required.
1306 //
1307 // UnsyncloadClass flag means both call loadClass(String) and do
1308 // not acquire the class loader lock even for class loaders that are
1309 // not parallelCapable. This was a risky transitional
1310 // flag for diagnostic purposes only. It is risky to call
1311 // custom class loaders without synchronization.
1312 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1313 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1314 // Do NOT assume this will be supported in future releases.
1315 //
1316 // Added MustCallLoadClassInternal in case we discover in the field
1317 // a customer that counts on this call
1318 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1319 JavaCalls::call_special(&result,
1320 class_loader,
1321 spec_klass,
1322 vmSymbols::loadClassInternal_name(),
1323 vmSymbols::string_class_signature(),
1324 string,
1325 CHECK_(nh));
1326 } else {
1327 JavaCalls::call_virtual(&result,
1328 class_loader,
1329 spec_klass,
1330 vmSymbols::loadClass_name(),
1331 vmSymbols::string_class_signature(),
1332 string,
1333 CHECK_(nh));
1334 }
1335
1336 assert(result.get_type() == T_OBJECT, "just checking");
1337 oop obj = (oop) result.get_jobject();
1338
1339 // Primitive classes return null since forName() can not be
1340 // used to obtain any of the Class objects representing primitives or void
1341 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1342 instanceKlassHandle k =
1343 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1344 // For user defined Java class loaders, check that the name returned is
1345 // the same as that requested. This check is done for the bootstrap
1346 // loader when parsing the class file.
1347 if (class_name == k->name()) {
1348 return k;
1349 }
1350 }
1351 // Class is not found or has the wrong name, return NULL
1352 return nh;
1353 }
1354 }
1355
1356 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1357
1358 Handle class_loader_h(THREAD, k->class_loader());
1359
1360 // for bootstrap and other parallel classloaders don't acquire lock,
1361 // use placeholder token
1362 // If a parallelCapable class loader calls define_instance_class instead of
1363 // find_or_define_instance_class to get here, we have a timing
1364 // hole with systemDictionary updates and check_constraints
1365 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1366 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1367 compute_loader_lock_object(class_loader_h, THREAD)),
1368 "define called without lock");
1369 }
1370
1371 // Check class-loading constraints. Throw exception if violation is detected.
1372 // Grabs and releases SystemDictionary_lock
1373 // The check_constraints/find_class call and update_dictionary sequence
1374 // must be "atomic" for a specific class/classloader pair so we never
1375 // define two different instanceKlasses for that class/classloader pair.
1376 // Existing classloaders will call define_instance_class with the
1377 // classloader lock held
1378 // Parallel classloaders will call find_or_define_instance_class
1379 // which will require a token to perform the define class
1380 Symbol* name_h = k->name();
1381 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1382 int d_index = dictionary()->hash_to_index(d_hash);
1383 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1384
1385 // Register class just loaded with class loader (placed in Vector)
1386 // Note we do this before updating the dictionary, as this can
1387 // fail with an OutOfMemoryError (if it does, we will *not* put this
1388 // class in the dictionary and will not update the class hierarchy).
1389 if (k->class_loader() != NULL) {
1390 methodHandle m(THREAD, Universe::loader_addClass_method());
1391 JavaValue result(T_VOID);
1392 JavaCallArguments args(class_loader_h);
1393 args.push_oop(Handle(THREAD, k->java_mirror()));
1394 JavaCalls::call(&result, m, &args, CHECK);
1395 }
1396
1397 // Add the new class. We need recompile lock during update of CHA.
1398 {
1399 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1400 int p_index = placeholders()->hash_to_index(p_hash);
1401
1402 MutexLocker mu_r(Compile_lock, THREAD);
1403
1404 // Add to class hierarchy, initialize vtables, and do possible
1405 // deoptimizations.
1406 add_to_hierarchy(k, CHECK); // No exception, but can block
1407
1408 // Add to systemDictionary - so other classes can see it.
1409 // Grabs and releases SystemDictionary_lock
1410 update_dictionary(d_index, d_hash, p_index, p_hash,
1411 k, class_loader_h, THREAD);
1412 }
1413 k->eager_initialize(THREAD);
1414
1415 // notify jvmti
1416 if (JvmtiExport::should_post_class_load()) {
1417 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1418 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1419
1420 }
1421 }
1422
1423 // Support parallel classloading
1424 // All parallel class loaders, including bootstrap classloader
1425 // lock a placeholder entry for this class/class_loader pair
1426 // to allow parallel defines of different classes for this class loader
1427 // With AllowParallelDefine flag==true, in case they do not synchronize around
1428 // FindLoadedClass/DefineClass, calls, we check for parallel
1429 // loading for them, wait if a defineClass is in progress
1430 // and return the initial requestor's results
1431 // This flag does not apply to the bootstrap classloader.
1432 // With AllowParallelDefine flag==false, call through to define_instance_class
1433 // which will throw LinkageError: duplicate class definition.
1434 // False is the requested default.
1435 // For better performance, the class loaders should synchronize
1436 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1437 // potentially waste time reading and parsing the bytestream.
1438 // Note: VM callers should ensure consistency of k/class_name,class_loader
1439 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1440
1441 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1442 Symbol* name_h = k->name(); // passed in class_name may be null
1443
1444 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader);
1445 int d_index = dictionary()->hash_to_index(d_hash);
1446
1447 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1448 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader);
1449 int p_index = placeholders()->hash_to_index(p_hash);
1450 PlaceholderEntry* probe;
1451
1452 {
1453 MutexLocker mu(SystemDictionary_lock, THREAD);
1454 // First check if class already defined
1455 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1456 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1457 if (check != NULL) {
1458 return(instanceKlassHandle(THREAD, check));
1459 }
1460 }
1461
1462 // Acquire define token for this class/classloader
1463 probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1464 // Wait if another thread defining in parallel
1465 // All threads wait - even those that will throw duplicate class: otherwise
1466 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1467 // if other thread has not finished updating dictionary
1468 while (probe->definer() != NULL) {
1469 SystemDictionary_lock->wait();
1470 }
1471 // Only special cases allow parallel defines and can use other thread's results
1472 // Other cases fall through, and may run into duplicate defines
1473 // caught by finding an entry in the SystemDictionary
1474 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) {
1475 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1476 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1477 SystemDictionary_lock->notify_all();
1478 #ifdef ASSERT
1479 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1480 assert(check != NULL, "definer missed recording success");
1481 #endif
1482 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1483 } else {
1484 // This thread will define the class (even if earlier thread tried and had an error)
1485 probe->set_definer(THREAD);
1486 }
1487 }
1488
1489 define_instance_class(k, THREAD);
1490
1491 Handle linkage_exception = Handle(); // null handle
1492
1493 // definer must notify any waiting threads
1494 {
1495 MutexLocker mu(SystemDictionary_lock, THREAD);
1496 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader);
1497 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1498 if (probe != NULL) {
1499 if (HAS_PENDING_EXCEPTION) {
1500 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1501 CLEAR_PENDING_EXCEPTION;
1502 } else {
1503 probe->set_instanceKlass(k());
1504 }
1505 probe->set_definer(NULL);
1506 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1507 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1508 SystemDictionary_lock->notify_all();
1509 }
1510 }
1511
1512 // Can't throw exception while holding lock due to rank ordering
1513 if (linkage_exception() != NULL) {
1514 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1515 }
1516
1517 return k;
1518 }
1519 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1520 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1521 if (class_loader.is_null()) {
1522 return Handle(THREAD, _system_loader_lock_obj);
1523 } else {
1524 return class_loader;
1525 }
1526 }
1527
1528 // This method is added to check how often we have to wait to grab loader
1529 // lock. The results are being recorded in the performance counters defined in
1530 // ClassLoader::_sync_systemLoaderLockContentionRate and
1531 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1532 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1533 if (!UsePerfData) {
1534 return;
1535 }
1536
1537 assert(!loader_lock.is_null(), "NULL lock object");
1538
1539 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1540 == ObjectSynchronizer::owner_other) {
1541 // contention will likely happen, so increment the corresponding
1542 // contention counter.
1543 if (loader_lock() == _system_loader_lock_obj) {
1544 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1545 } else {
1546 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1547 }
1548 }
1549 }
1550
1551 // ----------------------------------------------------------------------------
1552 // Lookup
1553
1554 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1555 Symbol* class_name,
1556 Handle class_loader) {
1557 assert_locked_or_safepoint(SystemDictionary_lock);
1558 assert (index == dictionary()->index_for(class_name, class_loader),
1559 "incorrect index?");
1560
1561 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1562 return k;
1563 }
1564
1565
1566 // Basic find on classes in the midst of being loaded
1567 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1568 Handle class_loader) {
1569 assert_locked_or_safepoint(SystemDictionary_lock);
1570 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1571 int p_index = placeholders()->hash_to_index(p_hash);
1572 return placeholders()->find_entry(p_index, p_hash, class_name, class_loader);
1573 }
1574
1575
1576 // Used for assertions and verification only
1577 klassOop SystemDictionary::find_class(Symbol* class_name, Handle class_loader) {
1578 #ifndef ASSERT
1579 guarantee(VerifyBeforeGC ||
1580 VerifyDuringGC ||
1581 VerifyBeforeExit ||
1582 VerifyAfterGC, "too expensive");
1583 #endif
1584 assert_locked_or_safepoint(SystemDictionary_lock);
1585
1586 // First look in the loaded class array
1587 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1588 int d_index = dictionary()->hash_to_index(d_hash);
1589 return find_class(d_index, d_hash, class_name, class_loader);
1590 }
1591
1592
1593 // Get the next class in the diictionary.
1594 klassOop SystemDictionary::try_get_next_class() {
1595 return dictionary()->try_get_next_class();
1596 }
1597
1598
1599 // ----------------------------------------------------------------------------
1600 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1601 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1602 // before a new class is used.
1603
1604 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1605 assert(k.not_null(), "just checking");
1606 assert_locked_or_safepoint(Compile_lock);
1607
1608 // Link into hierachy. Make sure the vtables are initialized before linking into
1609 k->append_to_sibling_list(); // add to superklass/sibling list
1610 k->process_interfaces(THREAD); // handle all "implements" declarations
1611 k->set_init_state(instanceKlass::loaded);
1612 // Now flush all code that depended on old class hierarchy.
1613 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1614 // Also, first reinitialize vtable because it may have gotten out of synch
1615 // while the new class wasn't connected to the class hierarchy.
1616 Universe::flush_dependents_on(k);
1617 }
1618
1619
1620 // ----------------------------------------------------------------------------
1621 // GC support
1622
1623 // Following roots during mark-sweep is separated in two phases.
1624 //
1625 // The first phase follows preloaded classes and all other system
1626 // classes, since these will never get unloaded anyway.
1627 //
1628 // The second phase removes (unloads) unreachable classes from the
1629 // system dictionary and follows the remaining classes' contents.
1630
1631 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1632 // Follow preloaded classes/mirrors and system loader object
1633 blk->do_oop(&_java_system_loader);
1634 preloaded_oops_do(blk);
1635 always_strong_classes_do(blk);
1636 }
1637
1638
1639 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1640 // Follow all system classes and temporary placeholders in dictionary
1641 dictionary()->always_strong_classes_do(blk);
1642
1643 // Placeholders. These are *always* strong roots, as they
1644 // represent classes we're actively loading.
1645 placeholders_do(blk);
1646
1647 // Visit extra methods
1648 invoke_method_table()->oops_do(blk);
1649 }
1650
1651
1652 void SystemDictionary::placeholders_do(OopClosure* blk) {
1653 placeholders()->oops_do(blk);
1654 }
1655
1656 // Calculate a "good" systemdictionary size based
1657 // on predicted or current loaded classes count
1658 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1659 int newsize = _old_default_sdsize;
1660 if ((classcount > 0) && !DumpSharedSpaces) {
1661 int desiredsize = classcount/_average_depth_goal;
1662 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1663 newsize = _primelist[++_sdgeneration]) {
1664 if (desiredsize <= newsize) {
1665 break;
1666 }
1667 }
1668 }
1669 return newsize;
1670 }
1671
1672 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1673 post_class_unload_events(is_alive);
1674 bool result = dictionary()->do_unloading(is_alive);
1675 constraints()->purge_loader_constraints(is_alive);
1676 resolution_errors()->purge_resolution_errors(is_alive);
1677 return result;
1678 }
1679
1680
1681 // The mirrors are scanned by shared_oops_do() which is
1682 // not called by oops_do(). In order to process oops in
1683 // a necessary order, shared_oops_do() is call by
1684 // Universe::oops_do().
1685 void SystemDictionary::oops_do(OopClosure* f) {
1686 // Adjust preloaded classes and system loader object
1687 f->do_oop(&_java_system_loader);
1688 preloaded_oops_do(f);
1689
1690 lazily_loaded_oops_do(f);
1691
1692 // Adjust dictionary
1693 dictionary()->oops_do(f);
1694
1695 // Visit extra methods
1696 invoke_method_table()->oops_do(f);
1697
1698 // Partially loaded classes
1699 placeholders()->oops_do(f);
1700
1701 // Adjust constraint table
1702 constraints()->oops_do(f);
1703
1704 // Adjust resolution error table
1705 resolution_errors()->oops_do(f);
1706 }
1707
1708
1709 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1710 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1711 f->do_oop((oop*) &_well_known_klasses[k]);
1712 }
1713
1714 {
1715 for (int i = 0; i < T_VOID+1; i++) {
1716 if (_box_klasses[i] != NULL) {
1717 assert(i >= T_BOOLEAN, "checking");
1718 f->do_oop((oop*) &_box_klasses[i]);
1719 }
1720 }
1721 }
1722
1723 // The basic type mirrors would have already been processed in
1724 // Universe::oops_do(), via a call to shared_oops_do(), so should
1725 // not be processed again.
1726
1727 f->do_oop((oop*) &_system_loader_lock_obj);
1728 FilteredFieldsMap::klasses_oops_do(f);
1729 }
1730
1731 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1732 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1733 }
1734
1735 // Just the classes from defining class loaders
1736 // Don't iterate over placeholders
1737 void SystemDictionary::classes_do(void f(klassOop)) {
1738 dictionary()->classes_do(f);
1739 }
1740
1741 // Added for initialize_itable_for_klass
1742 // Just the classes from defining class loaders
1743 // Don't iterate over placeholders
1744 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1745 dictionary()->classes_do(f, CHECK);
1746 }
1747
1748 // All classes, and their class loaders
1749 // Don't iterate over placeholders
1750 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1751 dictionary()->classes_do(f);
1752 }
1753
1754 // All classes, and their class loaders
1755 // (added for helpers that use HandleMarks and ResourceMarks)
1756 // Don't iterate over placeholders
1757 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1758 dictionary()->classes_do(f, CHECK);
1759 }
1760
1761 void SystemDictionary::placeholders_do(void f(Symbol*, oop)) {
1762 placeholders()->entries_do(f);
1763 }
1764
1765 void SystemDictionary::methods_do(void f(methodOop)) {
1766 dictionary()->methods_do(f);
1767 invoke_method_table()->methods_do(f);
1768 }
1769
1770 // ----------------------------------------------------------------------------
1771 // Lazily load klasses
1772
1773 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1774 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1775
1776 // if multiple threads calling this function, only one thread will load
1777 // the class. The other threads will find the loaded version once the
1778 // class is loaded.
1779 klassOop aos = _abstract_ownable_synchronizer_klass;
1780 if (aos == NULL) {
1781 klassOop k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1782 // Force a fence to prevent any read before the write completes
1783 OrderAccess::fence();
1784 _abstract_ownable_synchronizer_klass = k;
1785 }
1786 }
1787
1788 // ----------------------------------------------------------------------------
1789 // Initialization
1790
1791 void SystemDictionary::initialize(TRAPS) {
1792 // Allocate arrays
1793 assert(dictionary() == NULL,
1794 "SystemDictionary should only be initialized once");
1795 _sdgeneration = 0;
1796 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1797 _placeholders = new PlaceholderTable(_nof_buckets);
1798 _number_of_modifications = 0;
1799 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1800 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1801 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1802
1803 // Allocate private object used as system class loader lock
1804 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1805 // Initialize basic classes
1806 initialize_preloaded_classes(CHECK);
1807 }
1808
1809 // Compact table of directions on the initialization of klasses:
1810 static const short wk_init_info[] = {
1811 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1812 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1813 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1814 | (int)SystemDictionary::option ),
1815 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1816 #undef WK_KLASS_INIT_INFO
1817 0
1818 };
1819
1820 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1821 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1822 int info = wk_init_info[id - FIRST_WKID];
1823 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1824 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1825 klassOop* klassp = &_well_known_klasses[id];
1826 bool must_load = (init_opt < SystemDictionary::Opt);
1827 if ((*klassp) == NULL) {
1828 if (must_load) {
1829 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1830 } else {
1831 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1832 }
1833 }
1834 return ((*klassp) != NULL);
1835 }
1836
1837 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1838 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1839 for (int id = (int)start_id; id < (int)limit_id; id++) {
1840 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1841 int info = wk_init_info[id - FIRST_WKID];
1842 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1843 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1844
1845 initialize_wk_klass((WKID)id, opt, CHECK);
1846 }
1847
1848 // move the starting value forward to the limit:
1849 start_id = limit_id;
1850 }
1851
1852 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1853 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1854 // Preload commonly used klasses
1855 WKID scan = FIRST_WKID;
1856 // first do Object, String, Class
1857 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1858
1859 // Calculate offsets for String and Class classes since they are loaded and
1860 // can be used after this point.
1861 java_lang_String::compute_offsets();
1862 java_lang_Class::compute_offsets();
1863
1864 // Fixup mirrors for classes loaded before java.lang.Class.
1865 // These calls iterate over the objects currently in the perm gen
1866 // so calling them at this point is matters (not before when there
1867 // are fewer objects and not later after there are more objects
1868 // in the perm gen.
1869 Universe::initialize_basic_type_mirrors(CHECK);
1870 Universe::fixup_mirrors(CHECK);
1871
1872 // do a bunch more:
1873 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1874
1875 // Preload ref klasses and set reference types
1876 instanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1877 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1878
1879 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1880 instanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1881 instanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1882 instanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1883 instanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1884
1885 // JSR 292 classes
1886 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1887 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1888 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1889 if (EnableInvokeDynamic) {
1890 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1891 } else {
1892 // Skip the JSR 292 classes, if not enabled.
1893 scan = WKID(jsr292_group_end + 1);
1894 }
1895
1896 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1897
1898 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1899 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1900 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1901 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1902 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1903 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1904 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1905 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1906 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1907 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1908
1909 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1910 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1911 _has_loadClassInternal = (method != NULL);
1912 }
1913 { // Compute whether we should use checkPackageAccess or NOT
1914 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1915 _has_checkPackageAccess = (method != NULL);
1916 }
1917 }
1918
1919 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1920 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1921 BasicType SystemDictionary::box_klass_type(klassOop k) {
1922 assert(k != NULL, "");
1923 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1924 if (_box_klasses[i] == k)
1925 return (BasicType)i;
1926 }
1927 return T_OBJECT;
1928 }
1929
1930 KlassHandle SystemDictionaryHandles::box_klass(BasicType t) {
1931 if (t >= T_BOOLEAN && t <= T_VOID)
1932 return KlassHandle(&SystemDictionary::_box_klasses[t], true);
1933 else
1934 return KlassHandle();
1935 }
1936
1937 // Constraints on class loaders. The details of the algorithm can be
1938 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1939 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1940 // that the system dictionary needs to maintain a set of contraints that
1941 // must be satisfied by all classes in the dictionary.
1942 // if defining is true, then LinkageError if already in systemDictionary
1943 // if initiating loader, then ok if instanceKlass matches existing entry
1944
1945 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1946 instanceKlassHandle k,
1947 Handle class_loader, bool defining,
1948 TRAPS) {
1949 const char *linkage_error = NULL;
1950 {
1951 Symbol* name = k->name();
1952 MutexLocker mu(SystemDictionary_lock, THREAD);
1953
1954 klassOop check = find_class(d_index, d_hash, name, class_loader);
1955 if (check != (klassOop)NULL) {
1956 // if different instanceKlass - duplicate class definition,
1957 // else - ok, class loaded by a different thread in parallel,
1958 // we should only have found it if it was done loading and ok to use
1959 // system dictionary only holds instance classes, placeholders
1960 // also holds array classes
1961
1962 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
1963 if ((defining == true) || (k() != check)) {
1964 linkage_error = "loader (instance of %s): attempted duplicate class "
1965 "definition for name: \"%s\"";
1966 } else {
1967 return;
1968 }
1969 }
1970
1971 #ifdef ASSERT
1972 Symbol* ph_check = find_placeholder(name, class_loader);
1973 assert(ph_check == NULL || ph_check == name, "invalid symbol");
1974 #endif
1975
1976 if (linkage_error == NULL) {
1977 if (constraints()->check_or_update(k, class_loader, name) == false) {
1978 linkage_error = "loader constraint violation: loader (instance of %s)"
1979 " previously initiated loading for a different type with name \"%s\"";
1980 }
1981 }
1982 }
1983
1984 // Throw error now if needed (cannot throw while holding
1985 // SystemDictionary_lock because of rank ordering)
1986
1987 if (linkage_error) {
1988 ResourceMark rm(THREAD);
1989 const char* class_loader_name = loader_name(class_loader());
1990 char* type_name = k->name()->as_C_string();
1991 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1992 strlen(type_name);
1993 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1994 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1995 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1996 }
1997 }
1998
1999
2000 // Update system dictionary - done after check_constraint and add_to_hierachy
2001 // have been called.
2002 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2003 int p_index, unsigned int p_hash,
2004 instanceKlassHandle k,
2005 Handle class_loader,
2006 TRAPS) {
2007 // Compile_lock prevents systemDictionary updates during compilations
2008 assert_locked_or_safepoint(Compile_lock);
2009 Symbol* name = k->name();
2010
2011 {
2012 MutexLocker mu1(SystemDictionary_lock, THREAD);
2013
2014 // See whether biased locking is enabled and if so set it for this
2015 // klass.
2016 // Note that this must be done past the last potential blocking
2017 // point / safepoint. We enable biased locking lazily using a
2018 // VM_Operation to iterate the SystemDictionary and installing the
2019 // biasable mark word into each instanceKlass's prototype header.
2020 // To avoid race conditions where we accidentally miss enabling the
2021 // optimization for one class in the process of being added to the
2022 // dictionary, we must not safepoint after the test of
2023 // BiasedLocking::enabled().
2024 if (UseBiasedLocking && BiasedLocking::enabled()) {
2025 // Set biased locking bit for all loaded classes; it will be
2026 // cleared if revocation occurs too often for this type
2027 // NOTE that we must only do this when the class is initally
2028 // defined, not each time it is referenced from a new class loader
2029 if (k->class_loader() == class_loader()) {
2030 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2031 }
2032 }
2033
2034 // Assign a classid if one has not already been assigned. The
2035 // counter does not need to be atomically incremented since this
2036 // is only done while holding the SystemDictionary_lock.
2037 // All loaded classes get a unique ID.
2038 TRACE_INIT_ID(k);
2039
2040 // Check for a placeholder. If there, remove it and make a
2041 // new system dictionary entry.
2042 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2043 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2044 if (sd_check == NULL) {
2045 dictionary()->add_klass(name, class_loader, k);
2046 notice_modification();
2047 }
2048 #ifdef ASSERT
2049 sd_check = find_class(d_index, d_hash, name, class_loader);
2050 assert (sd_check != NULL, "should have entry in system dictionary");
2051 // Changed to allow PH to remain to complete class circularity checking
2052 // while only one thread can define a class at one time, multiple
2053 // classes can resolve the superclass for a class at one time,
2054 // and the placeholder is used to track that
2055 // Symbol* ph_check = find_placeholder(name, class_loader);
2056 // assert (ph_check == NULL, "should not have a placeholder entry");
2057 #endif
2058 SystemDictionary_lock->notify_all();
2059 }
2060 }
2061
2062
2063 // Try to find a class name using the loader constraints. The
2064 // loader constraints might know about a class that isn't fully loaded
2065 // yet and these will be ignored.
2066 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2067 Symbol* class_name, Handle class_loader, TRAPS) {
2068
2069 // First see if it has been loaded directly.
2070 // Force the protection domain to be null. (This removes protection checks.)
2071 Handle no_protection_domain;
2072 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2073 no_protection_domain, CHECK_NULL);
2074 if (klass != NULL)
2075 return klass;
2076
2077 // Now look to see if it has been loaded elsewhere, and is subject to
2078 // a loader constraint that would require this loader to return the
2079 // klass that is already loaded.
2080 if (FieldType::is_array(class_name)) {
2081 // For array classes, their klassOops are not kept in the
2082 // constraint table. The element klassOops are.
2083 FieldArrayInfo fd;
2084 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2085 if (t != T_OBJECT) {
2086 klass = Universe::typeArrayKlassObj(t);
2087 } else {
2088 MutexLocker mu(SystemDictionary_lock, THREAD);
2089 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2090 }
2091 // If element class already loaded, allocate array klass
2092 if (klass != NULL) {
2093 klass = Klass::cast(klass)->array_klass_or_null(fd.dimension());
2094 }
2095 } else {
2096 MutexLocker mu(SystemDictionary_lock, THREAD);
2097 // Non-array classes are easy: simply check the constraint table.
2098 klass = constraints()->find_constrained_klass(class_name, class_loader);
2099 }
2100
2101 return klass;
2102 }
2103
2104
2105 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2106 Handle class_loader1,
2107 Handle class_loader2,
2108 Thread* THREAD) {
2109 Symbol* constraint_name = NULL;
2110 if (!FieldType::is_array(class_name)) {
2111 constraint_name = class_name;
2112 } else {
2113 // For array classes, their klassOops are not kept in the
2114 // constraint table. The element classes are.
2115 FieldArrayInfo fd;
2116 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2117 // primitive types always pass
2118 if (t != T_OBJECT) {
2119 return true;
2120 } else {
2121 constraint_name = fd.object_key();
2122 }
2123 }
2124 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, class_loader1);
2125 int d_index1 = dictionary()->hash_to_index(d_hash1);
2126
2127 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, class_loader2);
2128 int d_index2 = dictionary()->hash_to_index(d_hash2);
2129 {
2130 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2131
2132 // Better never do a GC while we're holding these oops
2133 No_Safepoint_Verifier nosafepoint;
2134
2135 klassOop klass1 = find_class(d_index1, d_hash1, constraint_name, class_loader1);
2136 klassOop klass2 = find_class(d_index2, d_hash2, constraint_name, class_loader2);
2137 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2138 klass2, class_loader2);
2139 }
2140 }
2141
2142 // Add entry to resolution error table to record the error when the first
2143 // attempt to resolve a reference to a class has failed.
2144 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2145 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2146 int index = resolution_errors()->hash_to_index(hash);
2147 {
2148 MutexLocker ml(SystemDictionary_lock, Thread::current());
2149 resolution_errors()->add_entry(index, hash, pool, which, error);
2150 }
2151 }
2152
2153 // Lookup resolution error table. Returns error if found, otherwise NULL.
2154 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2155 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2156 int index = resolution_errors()->hash_to_index(hash);
2157 {
2158 MutexLocker ml(SystemDictionary_lock, Thread::current());
2159 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2160 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2161 }
2162 }
2163
2164
2165 // Signature constraints ensure that callers and callees agree about
2166 // the meaning of type names in their signatures. This routine is the
2167 // intake for constraints. It collects them from several places:
2168 //
2169 // * LinkResolver::resolve_method (if check_access is true) requires
2170 // that the resolving class (the caller) and the defining class of
2171 // the resolved method (the callee) agree on each type in the
2172 // method's signature.
2173 //
2174 // * LinkResolver::resolve_interface_method performs exactly the same
2175 // checks.
2176 //
2177 // * LinkResolver::resolve_field requires that the constant pool
2178 // attempting to link to a field agree with the field's defining
2179 // class about the type of the field signature.
2180 //
2181 // * klassVtable::initialize_vtable requires that, when a class
2182 // overrides a vtable entry allocated by a superclass, that the
2183 // overriding method (i.e., the callee) agree with the superclass
2184 // on each type in the method's signature.
2185 //
2186 // * klassItable::initialize_itable requires that, when a class fills
2187 // in its itables, for each non-abstract method installed in an
2188 // itable, the method (i.e., the callee) agree with the interface
2189 // on each type in the method's signature.
2190 //
2191 // All those methods have a boolean (check_access, checkconstraints)
2192 // which turns off the checks. This is used from specialized contexts
2193 // such as bootstrapping, dumping, and debugging.
2194 //
2195 // No direct constraint is placed between the class and its
2196 // supertypes. Constraints are only placed along linked relations
2197 // between callers and callees. When a method overrides or implements
2198 // an abstract method in a supertype (superclass or interface), the
2199 // constraints are placed as if the supertype were the caller to the
2200 // overriding method. (This works well, since callers to the
2201 // supertype have already established agreement between themselves and
2202 // the supertype.) As a result of all this, a class can disagree with
2203 // its supertype about the meaning of a type name, as long as that
2204 // class neither calls a relevant method of the supertype, nor is
2205 // called (perhaps via an override) from the supertype.
2206 //
2207 //
2208 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2209 //
2210 // Make sure all class components (including arrays) in the given
2211 // signature will be resolved to the same class in both loaders.
2212 // Returns the name of the type that failed a loader constraint check, or
2213 // NULL if no constraint failed. The returned C string needs cleaning up
2214 // with a ResourceMark in the caller. No exception except OOME is thrown.
2215 // Arrays are not added to the loader constraint table, their elements are.
2216 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2217 Handle loader1, Handle loader2,
2218 bool is_method, TRAPS) {
2219 // Nothing to do if loaders are the same.
2220 if (loader1() == loader2()) {
2221 return NULL;
2222 }
2223
2224 ResourceMark rm(THREAD);
2225 SignatureStream sig_strm(signature, is_method);
2226 while (!sig_strm.is_done()) {
2227 if (sig_strm.is_object()) {
2228 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2229 Symbol* sig = s;
2230 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2231 return sig->as_C_string();
2232 }
2233 }
2234 sig_strm.next();
2235 }
2236 return NULL;
2237 }
2238
2239
2240 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2241 Symbol* signature,
2242 TRAPS) {
2243 methodHandle empty;
2244 assert(EnableInvokeDynamic, "");
2245 assert(MethodHandles::is_signature_polymorphic(iid) &&
2246 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2247 iid != vmIntrinsics::_invokeGeneric,
2248 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2249
2250 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2251 int index = invoke_method_table()->hash_to_index(hash);
2252 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2253 methodHandle m;
2254 if (spe == NULL || spe->property_oop() == NULL) {
2255 spe = NULL;
2256 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2257 m = methodOopDesc::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2258 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2259 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2260
2261 // Now grab the lock. We might have to throw away the new method,
2262 // if a racing thread has managed to install one at the same time.
2263 {
2264 MutexLocker ml(SystemDictionary_lock, THREAD);
2265 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2266 if (spe == NULL)
2267 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2268 if (spe->property_oop() == NULL)
2269 spe->set_property_oop(m());
2270 }
2271 }
2272
2273 assert(spe != NULL && spe->property_oop() != NULL, "");
2274 m = methodOop(spe->property_oop());
2275 assert(m->is_method(), "");
2276
2277 return m;
2278 }
2279
2280 // Helper for unpacking the return value from linkMethod and linkCallSite.
2281 static methodHandle unpack_method_and_appendix(Handle mname,
2282 objArrayHandle appendix_box,
2283 Handle* appendix_result,
2284 TRAPS) {
2285 methodHandle empty;
2286 if (mname.not_null()) {
2287 oop vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2288 if (vmtarget != NULL && vmtarget->is_method()) {
2289 methodOop m = methodOop(vmtarget);
2290 oop appendix = appendix_box->obj_at(0);
2291 if (TraceMethodHandles) {
2292 #ifndef PRODUCT
2293 tty->print("Linked method="INTPTR_FORMAT": ", m);
2294 m->print();
2295 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2296 tty->cr();
2297 #endif //PRODUCT
2298 }
2299 (*appendix_result) = Handle(THREAD, appendix);
2300 return methodHandle(THREAD, m);
2301 }
2302 }
2303 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2304 return empty;
2305 }
2306
2307 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2308 Symbol* signature,
2309 KlassHandle accessing_klass,
2310 Handle *appendix_result,
2311 Handle *method_type_result,
2312 TRAPS) {
2313 methodHandle empty;
2314 assert(EnableInvokeDynamic, "");
2315 assert(!THREAD->is_Compiler_thread(), "");
2316 Handle method_type =
2317 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2318 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2319 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2320 }
2321
2322 KlassHandle mh_klass = SystemDictionaryHandles::MethodHandle_klass();
2323 int ref_kind = JVM_REF_invokeVirtual;
2324 Handle name_str = StringTable::intern(name, CHECK_(empty));
2325 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2326 assert(appendix_box->obj_at(0) == NULL, "");
2327
2328 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2329 JavaCallArguments args;
2330 args.push_oop(accessing_klass()->java_mirror());
2331 args.push_int(ref_kind);
2332 args.push_oop(mh_klass()->java_mirror());
2333 args.push_oop(name_str());
2334 args.push_oop(method_type());
2335 args.push_oop(appendix_box());
2336 JavaValue result(T_OBJECT);
2337 JavaCalls::call_static(&result,
2338 SystemDictionary::MethodHandleNatives_klass(),
2339 vmSymbols::linkMethod_name(),
2340 vmSymbols::linkMethod_signature(),
2341 &args, CHECK_(empty));
2342 Handle mname(THREAD, (oop) result.get_jobject());
2343 (*method_type_result) = method_type;
2344 return unpack_method_and_appendix(mname, appendix_box, appendix_result, THREAD);
2345 }
2346
2347
2348 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2349 // signature, as interpreted relative to the given class loader.
2350 // Because of class loader constraints, all method handle usage must be
2351 // consistent with this loader.
2352 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2353 KlassHandle accessing_klass,
2354 TRAPS) {
2355 Handle empty;
2356 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2357 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2358 int index = invoke_method_table()->hash_to_index(hash);
2359 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2360 if (spe != NULL && spe->property_oop() != NULL) {
2361 assert(java_lang_invoke_MethodType::is_instance(spe->property_oop()), "");
2362 return Handle(THREAD, spe->property_oop());
2363 } else if (THREAD->is_Compiler_thread()) {
2364 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2365 return Handle(); // do not attempt from within compiler, unless it was cached
2366 }
2367
2368 Handle class_loader, protection_domain;
2369 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2370 int npts = ArgumentCount(signature).size();
2371 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2372 int arg = 0;
2373 Handle rt; // the return type from the signature
2374 ResourceMark rm(THREAD);
2375 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2376 oop mirror = NULL;
2377 if (is_on_bcp) {
2378 // Note: class_loader & protection_domain are both null at this point.
2379 mirror = ss.as_java_mirror(class_loader, protection_domain,
2380 SignatureStream::ReturnNull, CHECK_(empty));
2381 if (mirror == NULL) {
2382 // fall back from BCP to accessing_klass
2383 if (accessing_klass.not_null()) {
2384 class_loader = Handle(THREAD, instanceKlass::cast(accessing_klass())->class_loader());
2385 protection_domain = Handle(THREAD, instanceKlass::cast(accessing_klass())->protection_domain());
2386 }
2387 is_on_bcp = false;
2388 }
2389 }
2390 if (!is_on_bcp) {
2391 // Resolve, throwing a real error if it doesn't work.
2392 mirror = ss.as_java_mirror(class_loader, protection_domain,
2393 SignatureStream::NCDFError, CHECK_(empty));
2394 }
2395 if (ss.at_return_type())
2396 rt = Handle(THREAD, mirror);
2397 else
2398 pts->obj_at_put(arg++, mirror);
2399
2400 // Check accessibility.
2401 if (ss.is_object() && accessing_klass.not_null()) {
2402 klassOop sel_klass = java_lang_Class::as_klassOop(mirror);
2403 mirror = NULL; // safety
2404 // Emulate constantPoolOopDesc::verify_constant_pool_resolve.
2405 if (Klass::cast(sel_klass)->oop_is_objArray())
2406 sel_klass = objArrayKlass::cast(sel_klass)->bottom_klass();
2407 if (Klass::cast(sel_klass)->oop_is_instance()) {
2408 KlassHandle sel_kh(THREAD, sel_klass);
2409 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2410 }
2411 }
2412 }
2413 assert(arg == npts, "");
2414
2415 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2416 JavaCallArguments args(Handle(THREAD, rt()));
2417 args.push_oop(pts());
2418 JavaValue result(T_OBJECT);
2419 JavaCalls::call_static(&result,
2420 SystemDictionary::MethodHandleNatives_klass(),
2421 vmSymbols::findMethodHandleType_name(),
2422 vmSymbols::findMethodHandleType_signature(),
2423 &args, CHECK_(empty));
2424 Handle method_type(THREAD, (oop) result.get_jobject());
2425
2426 if (is_on_bcp) {
2427 // We can cache this MethodType inside the JVM.
2428 MutexLocker ml(SystemDictionary_lock, THREAD);
2429 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2430 if (spe == NULL)
2431 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2432 if (spe->property_oop() == NULL) {
2433 spe->set_property_oop(method_type());
2434 }
2435 }
2436
2437 // report back to the caller with the MethodType
2438 return method_type;
2439 }
2440
2441 // Ask Java code to find or construct a method handle constant.
2442 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2443 int ref_kind, //e.g., JVM_REF_invokeVirtual
2444 KlassHandle callee,
2445 Symbol* name_sym,
2446 Symbol* signature,
2447 TRAPS) {
2448 Handle empty;
2449 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2450 Handle type;
2451 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2452 type = find_method_handle_type(signature, caller, CHECK_(empty));
2453 } else {
2454 ResourceMark rm(THREAD);
2455 SignatureStream ss(signature, false);
2456 if (!ss.is_done()) {
2457 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2458 SignatureStream::NCDFError, CHECK_(empty));
2459 type = Handle(THREAD, mirror);
2460 ss.next();
2461 if (!ss.is_done()) type = Handle(); // error!
2462 }
2463 }
2464 if (type.is_null()) {
2465 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2466 }
2467
2468 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2469 JavaCallArguments args;
2470 args.push_oop(caller->java_mirror()); // the referring class
2471 args.push_int(ref_kind);
2472 args.push_oop(callee->java_mirror()); // the target class
2473 args.push_oop(name());
2474 args.push_oop(type());
2475 JavaValue result(T_OBJECT);
2476 JavaCalls::call_static(&result,
2477 SystemDictionary::MethodHandleNatives_klass(),
2478 vmSymbols::linkMethodHandleConstant_name(),
2479 vmSymbols::linkMethodHandleConstant_signature(),
2480 &args, CHECK_(empty));
2481 return Handle(THREAD, (oop) result.get_jobject());
2482 }
2483
2484 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2485 // name and signature, as interpreted relative to the given class loader.
2486 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2487 Handle bootstrap_specifier,
2488 Symbol* name,
2489 Symbol* type,
2490 Handle *appendix_result,
2491 Handle *method_type_result,
2492 TRAPS) {
2493 methodHandle empty;
2494 Handle bsm, info;
2495 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2496 bsm = bootstrap_specifier;
2497 } else {
2498 assert(bootstrap_specifier->is_objArray(), "");
2499 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2500 int len = args->length();
2501 assert(len >= 1, "");
2502 bsm = Handle(THREAD, args->obj_at(0));
2503 if (len > 1) {
2504 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2505 for (int i = 1; i < len; i++)
2506 args1->obj_at_put(i-1, args->obj_at(i));
2507 info = Handle(THREAD, args1);
2508 }
2509 }
2510 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2511 "caller must supply a valid BSM");
2512
2513 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2514 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2515
2516 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2517 assert(appendix_box->obj_at(0) == NULL, "");
2518
2519 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2520 JavaCallArguments args;
2521 args.push_oop(caller->java_mirror());
2522 args.push_oop(bsm());
2523 args.push_oop(method_name());
2524 args.push_oop(method_type());
2525 args.push_oop(info());
2526 args.push_oop(appendix_box);
2527 JavaValue result(T_OBJECT);
2528 JavaCalls::call_static(&result,
2529 SystemDictionary::MethodHandleNatives_klass(),
2530 vmSymbols::linkCallSite_name(),
2531 vmSymbols::linkCallSite_signature(),
2532 &args, CHECK_(empty));
2533 Handle mname(THREAD, (oop) result.get_jobject());
2534 (*method_type_result) = method_type;
2535 return unpack_method_and_appendix(mname, appendix_box, appendix_result, THREAD);
2536 }
2537
2538 // Since the identity hash code for symbols changes when the symbols are
2539 // moved from the regular perm gen (hash in the mark word) to the shared
2540 // spaces (hash is the address), the classes loaded into the dictionary
2541 // may be in the wrong buckets.
2542
2543 void SystemDictionary::reorder_dictionary() {
2544 dictionary()->reorder_dictionary();
2545 }
2546
2547
2548 void SystemDictionary::copy_buckets(char** top, char* end) {
2549 dictionary()->copy_buckets(top, end);
2550 }
2551
2552
2553 void SystemDictionary::copy_table(char** top, char* end) {
2554 dictionary()->copy_table(top, end);
2555 }
2556
2557
2558 void SystemDictionary::reverse() {
2559 dictionary()->reverse();
2560 }
2561
2562 int SystemDictionary::number_of_classes() {
2563 return dictionary()->number_of_entries();
2564 }
2565
2566
2567 // ----------------------------------------------------------------------------
2568 #ifndef PRODUCT
2569
2570 void SystemDictionary::print() {
2571 dictionary()->print();
2572
2573 // Placeholders
2574 GCMutexLocker mu(SystemDictionary_lock);
2575 placeholders()->print();
2576
2577 // loader constraints - print under SD_lock
2578 constraints()->print();
2579 }
2580
2581 #endif
2582
2583 void SystemDictionary::verify() {
2584 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2585 guarantee(constraints() != NULL,
2586 "Verify of loader constraints failed");
2587 guarantee(dictionary()->number_of_entries() >= 0 &&
2588 placeholders()->number_of_entries() >= 0,
2589 "Verify of system dictionary failed");
2590
2591 // Verify dictionary
2592 dictionary()->verify();
2593
2594 GCMutexLocker mu(SystemDictionary_lock);
2595 placeholders()->verify();
2596
2597 // Verify constraint table
2598 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2599 constraints()->verify(dictionary(), placeholders());
2600 }
2601
2602
2603 void SystemDictionary::verify_obj_klass_present(Handle obj,
2604 Symbol* class_name,
2605 Handle class_loader) {
2606 GCMutexLocker mu(SystemDictionary_lock);
2607 Symbol* name;
2608
2609 klassOop probe = find_class(class_name, class_loader);
2610 if (probe == NULL) {
2611 probe = SystemDictionary::find_shared_class(class_name);
2612 if (probe == NULL) {
2613 name = find_placeholder(class_name, class_loader);
2614 }
2615 }
2616 guarantee(probe != NULL || name != NULL,
2617 "Loaded klasses should be in SystemDictionary");
2618 }
2619
2620 jlong SystemDictionary::class_load_tracing_begin(void) {
2621 #if INCLUDE_TRACE
2622 return os::elapsed_counter();
2623 #endif
2624 return 0;
2625 }
2626
2627 // utililty function for class load event
2628 void SystemDictionary::post_class_load_event(jlong start_time,
2629 instanceKlassHandle k, Handle initiating_loader) {
2630 #if INCLUDE_TRACE
2631 EventClassLoad event(UNTIMED);
2632 if (event.should_commit()) {
2633 event.set_endtime(os::elapsed_counter());
2634 event.set_starttime(start_time);
2635 event.set_loadedClass(k());
2636 oop defining_class_loader = k->class_loader();
2637 event.set_definingClassLoader(defining_class_loader != NULL ?
2638 defining_class_loader->klass() : NULL);
2639 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2640 event.set_initiatingClassLoader(class_loader != NULL ?
2641 class_loader->klass() : NULL);
2642 event.commit();
2643 }
2644 #endif /* INCLUDE_TRACE */
2645 }
2646
2647 void SystemDictionary::post_class_unload_events(BoolObjectClosure* is_alive) {
2648 #if INCLUDE_TRACE
2649 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");
2650 if (Tracing::enabled()) {
2651 _should_write_unload_events = Tracing::is_event_enabled(TraceClassUnloadEvent);
2652 _class_unload_time = Tracing::time();
2653 _is_alive = is_alive;
2654 classes_do(&class_unload_event);
2655
2656 if (_no_of_classes_unloading > 0) {
2657 Tracing::on_unloading_classes(is_alive, _no_of_classes_unloading);
2658 _no_of_classes_unloading = 0;
2659 }
2660 _should_write_unload_events = false;
2661 _is_alive = NULL;
2662 }
2663 #endif /* INCLUDE_TRACE */
2664 }
2665
2666 #if INCLUDE_TRACE
2667 TracingTime SystemDictionary::_class_unload_time;
2668 BoolObjectClosure* SystemDictionary::_is_alive = NULL;
2669 int SystemDictionary::_no_of_classes_unloading = 0;
2670 bool SystemDictionary::_should_write_unload_events = false;
2671
2672 void SystemDictionary::class_unload_event(klassOop curklass) {
2673
2674 Klass* myklass = curklass->klass_part();
2675 oop class_loader = myklass->class_loader();
2676
2677 if (class_loader != NULL && _is_alive != NULL && !_is_alive->do_object_b(class_loader)) {
2678 _no_of_classes_unloading++;
2679 if (_should_write_unload_events) {
2680 // post class unload event
2681 EventClassUnload event(UNTIMED);
2682 event.set_endtime(_class_unload_time);
2683 event.set_unloadedClass(curklass);
2684 event.set_definingClassLoader(class_loader->klass());
2685 event.commit();
2686 }
2687 }
2688 }
2689
2690 #endif /* INCLUDE_TRACE */
2691
2692 #ifndef PRODUCT
2693
2694 // statistics code
2695 class ClassStatistics: AllStatic {
2696 private:
2697 static int nclasses; // number of classes
2698 static int nmethods; // number of methods
2699 static int nmethoddata; // number of methodData
2700 static int class_size; // size of class objects in words
2701 static int method_size; // size of method objects in words
2702 static int debug_size; // size of debug info in methods
2703 static int methoddata_size; // size of methodData objects in words
2704
2705 static void do_class(klassOop k) {
2706 nclasses++;
2707 class_size += k->size();
2708 if (k->klass_part()->oop_is_instance()) {
2709 instanceKlass* ik = (instanceKlass*)k->klass_part();
2710 class_size += ik->methods()->size();
2711 class_size += ik->constants()->size();
2712 class_size += ik->local_interfaces()->size();
2713 class_size += ik->transitive_interfaces()->size();
2714 // We do not have to count implementors, since we only store one!
2715 class_size += ik->fields()->length();
2716 }
2717 }
2718
2719 static void do_method(methodOop m) {
2720 nmethods++;
2721 method_size += m->size();
2722 // class loader uses same objArray for empty vectors, so don't count these
2723 if (m->has_stackmap_table()) {
2724 method_size += m->stackmap_data()->size();
2725 }
2726
2727 methodDataOop mdo = m->method_data();
2728 if (mdo != NULL) {
2729 nmethoddata++;
2730 methoddata_size += mdo->size();
2731 }
2732 }
2733
2734 public:
2735 static void print() {
2736 SystemDictionary::classes_do(do_class);
2737 SystemDictionary::methods_do(do_method);
2738 tty->print_cr("Class statistics:");
2739 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2740 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2741 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2742 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2743 }
2744 };
2745
2746
2747 int ClassStatistics::nclasses = 0;
2748 int ClassStatistics::nmethods = 0;
2749 int ClassStatistics::nmethoddata = 0;
2750 int ClassStatistics::class_size = 0;
2751 int ClassStatistics::method_size = 0;
2752 int ClassStatistics::debug_size = 0;
2753 int ClassStatistics::methoddata_size = 0;
2754
2755 void SystemDictionary::print_class_statistics() {
2756 ResourceMark rm;
2757 ClassStatistics::print();
2758 }
2759
2760
2761 class MethodStatistics: AllStatic {
2762 public:
2763 enum {
2764 max_parameter_size = 10
2765 };
2766 private:
2767
2768 static int _number_of_methods;
2769 static int _number_of_final_methods;
2770 static int _number_of_static_methods;
2771 static int _number_of_native_methods;
2772 static int _number_of_synchronized_methods;
2773 static int _number_of_profiled_methods;
2774 static int _number_of_bytecodes;
2775 static int _parameter_size_profile[max_parameter_size];
2776 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2777
2778 static void initialize() {
2779 _number_of_methods = 0;
2780 _number_of_final_methods = 0;
2781 _number_of_static_methods = 0;
2782 _number_of_native_methods = 0;
2783 _number_of_synchronized_methods = 0;
2784 _number_of_profiled_methods = 0;
2785 _number_of_bytecodes = 0;
2786 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2787 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2788 };
2789
2790 static void do_method(methodOop m) {
2791 _number_of_methods++;
2792 // collect flag info
2793 if (m->is_final() ) _number_of_final_methods++;
2794 if (m->is_static() ) _number_of_static_methods++;
2795 if (m->is_native() ) _number_of_native_methods++;
2796 if (m->is_synchronized()) _number_of_synchronized_methods++;
2797 if (m->method_data() != NULL) _number_of_profiled_methods++;
2798 // collect parameter size info (add one for receiver, if any)
2799 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2800 // collect bytecodes info
2801 {
2802 Thread *thread = Thread::current();
2803 HandleMark hm(thread);
2804 BytecodeStream s(methodHandle(thread, m));
2805 Bytecodes::Code c;
2806 while ((c = s.next()) >= 0) {
2807 _number_of_bytecodes++;
2808 _bytecodes_profile[c]++;
2809 }
2810 }
2811 }
2812
2813 public:
2814 static void print() {
2815 initialize();
2816 SystemDictionary::methods_do(do_method);
2817 // generate output
2818 tty->cr();
2819 tty->print_cr("Method statistics (static):");
2820 // flag distribution
2821 tty->cr();
2822 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2823 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2824 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2825 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2826 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2827 // parameter size profile
2828 tty->cr();
2829 { int tot = 0;
2830 int avg = 0;
2831 for (int i = 0; i < max_parameter_size; i++) {
2832 int n = _parameter_size_profile[i];
2833 tot += n;
2834 avg += n*i;
2835 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2836 }
2837 assert(tot == _number_of_methods, "should be the same");
2838 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2839 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2840 }
2841 // bytecodes profile
2842 tty->cr();
2843 { int tot = 0;
2844 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2845 if (Bytecodes::is_defined(i)) {
2846 Bytecodes::Code c = Bytecodes::cast(i);
2847 int n = _bytecodes_profile[c];
2848 tot += n;
2849 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2850 }
2851 }
2852 assert(tot == _number_of_bytecodes, "should be the same");
2853 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2854 }
2855 tty->cr();
2856 }
2857 };
2858
2859 int MethodStatistics::_number_of_methods;
2860 int MethodStatistics::_number_of_final_methods;
2861 int MethodStatistics::_number_of_static_methods;
2862 int MethodStatistics::_number_of_native_methods;
2863 int MethodStatistics::_number_of_synchronized_methods;
2864 int MethodStatistics::_number_of_profiled_methods;
2865 int MethodStatistics::_number_of_bytecodes;
2866 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2867 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2868
2869
2870 void SystemDictionary::print_method_statistics() {
2871 MethodStatistics::print();
2872 }
2873
2874 #endif // PRODUCT