1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/dictionary.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/loaderConstraints.hpp"
29 #include "classfile/placeholders.hpp"
30 #include "classfile/resolutionErrors.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "interpreter/bytecodeStream.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "memory/gcLocker.hpp"
36 #include "memory/oopFactory.hpp"
37 #include "oops/instanceKlass.hpp"
38 #include "oops/instanceRefKlass.hpp"
39 #include "oops/klass.inline.hpp"
40 #include "oops/methodDataOop.hpp"
41 #include "oops/objArrayKlass.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/oop.inline2.hpp"
44 #include "oops/typeArrayKlass.hpp"
45 #include "prims/jvmtiEnvBase.hpp"
46 #include "prims/methodHandles.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/fieldType.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/java.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "runtime/signature.hpp"
54 #include "services/classLoadingService.hpp"
55 #include "services/threadService.hpp"
56
57
58 Dictionary* SystemDictionary::_dictionary = NULL;
59 PlaceholderTable* SystemDictionary::_placeholders = NULL;
60 Dictionary* SystemDictionary::_shared_dictionary = NULL;
61 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
62 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
63 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
64
65
66 int SystemDictionary::_number_of_modifications = 0;
67 int SystemDictionary::_sdgeneration = 0;
68 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
69 20201,40423,99991};
70
71 oop SystemDictionary::_system_loader_lock_obj = NULL;
72
73 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
74 = { NULL /*, NULL...*/ };
75
76 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
77
78 oop SystemDictionary::_java_system_loader = NULL;
79
80 bool SystemDictionary::_has_loadClassInternal = false;
81 bool SystemDictionary::_has_checkPackageAccess = false;
82
83 // lazily initialized klass variables
84 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
85
86
87 // ----------------------------------------------------------------------------
88 // Java-level SystemLoader
89
90 oop SystemDictionary::java_system_loader() {
91 return _java_system_loader;
92 }
93
94 void SystemDictionary::compute_java_system_loader(TRAPS) {
95 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
96 JavaValue result(T_OBJECT);
97 JavaCalls::call_static(&result,
98 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
99 vmSymbols::getSystemClassLoader_name(),
100 vmSymbols::void_classloader_signature(),
101 CHECK);
102
103 _java_system_loader = (oop)result.get_jobject();
104 }
105
106
107 // ----------------------------------------------------------------------------
108 // debugging
109
110 #ifdef ASSERT
111
112 // return true if class_name contains no '.' (internal format is '/')
113 bool SystemDictionary::is_internal_format(Symbol* class_name) {
114 if (class_name != NULL) {
115 ResourceMark rm;
116 char* name = class_name->as_C_string();
117 return strchr(name, '.') == NULL;
118 } else {
119 return true;
120 }
121 }
122
123 #endif
124
125 // ----------------------------------------------------------------------------
126 // Parallel class loading check
127
128 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
129 if (UnsyncloadClass || class_loader.is_null()) return true;
130 if (AlwaysLockClassLoader) return false;
131 return java_lang_ClassLoader::parallelCapable(class_loader());
132 }
133 // ----------------------------------------------------------------------------
134 // ParallelDefineClass flag does not apply to bootclass loader
135 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
136 if (class_loader.is_null()) return false;
137 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
138 return true;
139 }
140 return false;
141 }
142 // ----------------------------------------------------------------------------
143 // Resolving of classes
144
145 // Forwards to resolve_or_null
146
147 klassOop SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
148 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
149 if (HAS_PENDING_EXCEPTION || klass == NULL) {
150 KlassHandle k_h(THREAD, klass);
151 // can return a null klass
152 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
153 }
154 return klass;
155 }
156
157 klassOop SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
158 if (HAS_PENDING_EXCEPTION) {
159 // If we have a pending exception we forward it to the caller, unless throw_error is true,
160 // in which case we have to check whether the pending exception is a ClassNotFoundException,
161 // and if so convert it to a NoClassDefFoundError
162 // And chain the original ClassNotFoundException
163 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
164 ResourceMark rm(THREAD);
165 assert(klass_h() == NULL, "Should not have result with exception pending");
166 Handle e(THREAD, PENDING_EXCEPTION);
167 CLEAR_PENDING_EXCEPTION;
168 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
169 } else {
170 return NULL;
171 }
172 }
173 // Class not found, throw appropriate error or exception depending on value of throw_error
174 if (klass_h() == NULL) {
175 ResourceMark rm(THREAD);
176 if (throw_error) {
177 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
178 } else {
179 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
180 }
181 }
182 return (klassOop)klass_h();
183 }
184
185
186 klassOop SystemDictionary::resolve_or_fail(Symbol* class_name,
187 bool throw_error, TRAPS)
188 {
189 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
190 }
191
192
193 // Forwards to resolve_instance_class_or_null
194
195 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
196 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
197 if (FieldType::is_array(class_name)) {
198 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
199 } else if (FieldType::is_obj(class_name)) {
200 ResourceMark rm(THREAD);
201 // Ignore wrapping L and ;.
202 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
203 class_name->utf8_length() - 2, CHECK_NULL);
204 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
205 } else {
206 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
207 }
208 }
209
210 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
211 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
212 }
213
214 // Forwards to resolve_instance_class_or_null
215
216 klassOop SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
217 Handle class_loader,
218 Handle protection_domain,
219 TRAPS) {
220 assert(FieldType::is_array(class_name), "must be array");
221 klassOop k = NULL;
222 FieldArrayInfo fd;
223 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
224 // of this call
225 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
226 if (t == T_OBJECT) {
227 // naked oop "k" is OK here -- we assign back into it
228 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
229 class_loader,
230 protection_domain,
231 CHECK_NULL);
232 if (k != NULL) {
233 k = Klass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
234 }
235 } else {
236 k = Universe::typeArrayKlassObj(t);
237 k = typeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
238 }
239 return k;
240 }
241
242
243 // Must be called for any super-class or super-interface resolution
244 // during class definition to allow class circularity checking
245 // super-interface callers:
246 // parse_interfaces - for defineClass & jvmtiRedefineClasses
247 // super-class callers:
248 // ClassFileParser - for defineClass & jvmtiRedefineClasses
249 // load_shared_class - while loading a class from shared archive
250 // resolve_instance_class_or_null:
251 // via: handle_parallel_super_load
252 // when resolving a class that has an existing placeholder with
253 // a saved superclass [i.e. a defineClass is currently in progress]
254 // if another thread is trying to resolve the class, it must do
255 // super-class checks on its own thread to catch class circularity
256 // This last call is critical in class circularity checking for cases
257 // where classloading is delegated to different threads and the
258 // classloader lock is released.
259 // Take the case: Base->Super->Base
260 // 1. If thread T1 tries to do a defineClass of class Base
261 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
262 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
263 // so it tries to load Super
264 // 3. If we load the class internally, or user classloader uses same thread
265 // loadClassFromxxx or defineClass via parseClassFile Super ...
266 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
267 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
268 // 3.4 calls resolve_super_or_fail Base
269 // 3.5 finds T1,Base -> throws class circularity
270 //OR 4. If T2 tries to resolve Super via defineClass Super ...
271 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
272 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
273 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
274 // 4.4 finds T2, Super -> throws class circularity
275 // Must be called, even if superclass is null, since this is
276 // where the placeholder entry is created which claims this
277 // thread is loading this class/classloader.
278 klassOop SystemDictionary::resolve_super_or_fail(Symbol* child_name,
279 Symbol* class_name,
280 Handle class_loader,
281 Handle protection_domain,
282 bool is_superclass,
283 TRAPS) {
284
285 // Try to get one of the well-known klasses.
286 // They are trusted, and do not participate in circularities.
287 if (LinkWellKnownClasses) {
288 klassOop k = find_well_known_klass(class_name);
289 if (k != NULL) {
290 return k;
291 }
292 }
293
294 // Double-check, if child class is already loaded, just return super-class,interface
295 // Don't add a placedholder if already loaded, i.e. already in system dictionary
296 // Make sure there's a placeholder for the *child* before resolving.
297 // Used as a claim that this thread is currently loading superclass/classloader
298 // Used here for ClassCircularity checks and also for heap verification
299 // (every instanceKlass in the heap needs to be in the system dictionary
300 // or have a placeholder).
301 // Must check ClassCircularity before checking if super class is already loaded
302 //
303 // We might not already have a placeholder if this child_name was
304 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
305 // the name of the class might not be known until the stream is actually
306 // parsed.
307 // Bugs 4643874, 4715493
308 // compute_hash can have a safepoint
309
310 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
311 int d_index = dictionary()->hash_to_index(d_hash);
312 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
313 int p_index = placeholders()->hash_to_index(p_hash);
314 // can't throw error holding a lock
315 bool child_already_loaded = false;
316 bool throw_circularity_error = false;
317 {
318 MutexLocker mu(SystemDictionary_lock, THREAD);
319 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
320 klassOop quicksuperk;
321 // to support // loading: if child done loading, just return superclass
322 // if class_name, & class_loader don't match:
323 // if initial define, SD update will give LinkageError
324 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
325 // so we don't throw an exception here.
326 // see: nsk redefclass014 & java.lang.instrument Instrument032
327 if ((childk != NULL ) && (is_superclass) &&
328 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
329
330 ((Klass::cast(quicksuperk)->name() == class_name) &&
331 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
332 return quicksuperk;
333 } else {
334 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
335 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
336 throw_circularity_error = true;
337 }
338 }
339 if (!throw_circularity_error) {
340 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
341 }
342 }
343 if (throw_circularity_error) {
344 ResourceMark rm(THREAD);
345 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
346 }
347
348 // java.lang.Object should have been found above
349 assert(class_name != NULL, "null super class for resolving");
350 // Resolve the super class or interface, check results on return
351 klassOop superk = NULL;
352 superk = SystemDictionary::resolve_or_null(class_name,
353 class_loader,
354 protection_domain,
355 THREAD);
356
357 KlassHandle superk_h(THREAD, superk);
358
359 // Note: clean up of placeholders currently in callers of
360 // resolve_super_or_fail - either at update_dictionary time
361 // or on error
362 {
363 MutexLocker mu(SystemDictionary_lock, THREAD);
364 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
365 if (probe != NULL) {
366 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
367 }
368 }
369 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
370 // can null superk
371 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
372 }
373
374 return superk_h();
375 }
376
377 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
378 Handle class_loader,
379 Handle protection_domain,
380 TRAPS) {
381 if(!has_checkPackageAccess()) return;
382
383 // Now we have to call back to java to check if the initating class has access
384 JavaValue result(T_VOID);
385 if (TraceProtectionDomainVerification) {
386 // Print out trace information
387 tty->print_cr("Checking package access");
388 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
389 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
390 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
391 }
392
393 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
394
395 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
396 JavaCalls::call_special(&result,
397 class_loader,
398 system_loader,
399 vmSymbols::checkPackageAccess_name(),
400 vmSymbols::class_protectiondomain_signature(),
401 Handle(THREAD, klass->java_mirror()),
402 protection_domain,
403 THREAD);
404
405 if (TraceProtectionDomainVerification) {
406 if (HAS_PENDING_EXCEPTION) {
407 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
408 } else {
409 tty->print_cr(" -> granted");
410 }
411 tty->cr();
412 }
413
414 if (HAS_PENDING_EXCEPTION) return;
415
416 // If no exception has been thrown, we have validated the protection domain
417 // Insert the protection domain of the initiating class into the set.
418 {
419 // We recalculate the entry here -- we've called out to java since
420 // the last time it was calculated.
421 Symbol* kn = klass->name();
422 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
423 int d_index = dictionary()->hash_to_index(d_hash);
424
425 MutexLocker mu(SystemDictionary_lock, THREAD);
426 {
427 // Note that we have an entry, and entries can be deleted only during GC,
428 // so we cannot allow GC to occur while we're holding this entry.
429
430 // We're using a No_Safepoint_Verifier to catch any place where we
431 // might potentially do a GC at all.
432 // SystemDictionary::do_unloading() asserts that classes are only
433 // unloaded at a safepoint.
434 No_Safepoint_Verifier nosafepoint;
435 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
436 protection_domain, THREAD);
437 }
438 }
439 }
440
441 // We only get here if this thread finds that another thread
442 // has already claimed the placeholder token for the current operation,
443 // but that other thread either never owned or gave up the
444 // object lock
445 // Waits on SystemDictionary_lock to indicate placeholder table updated
446 // On return, caller must recheck placeholder table state
447 //
448 // We only get here if
449 // 1) custom classLoader, i.e. not bootstrap classloader
450 // 2) UnsyncloadClass not set
451 // 3) custom classLoader has broken the class loader objectLock
452 // so another thread got here in parallel
453 //
454 // lockObject must be held.
455 // Complicated dance due to lock ordering:
456 // Must first release the classloader object lock to
457 // allow initial definer to complete the class definition
458 // and to avoid deadlock
459 // Reclaim classloader lock object with same original recursion count
460 // Must release SystemDictionary_lock after notify, since
461 // class loader lock must be claimed before SystemDictionary_lock
462 // to prevent deadlocks
463 //
464 // The notify allows applications that did an untimed wait() on
465 // the classloader object lock to not hang.
466 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
467 assert_lock_strong(SystemDictionary_lock);
468
469 bool calledholdinglock
470 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
471 assert(calledholdinglock,"must hold lock for notify");
472 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
473 ObjectSynchronizer::notifyall(lockObject, THREAD);
474 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
475 SystemDictionary_lock->wait();
476 SystemDictionary_lock->unlock();
477 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
478 SystemDictionary_lock->lock();
479 }
480
481 // If the class in is in the placeholder table, class loading is in progress
482 // For cases where the application changes threads to load classes, it
483 // is critical to ClassCircularity detection that we try loading
484 // the superclass on the same thread internally, so we do parallel
485 // super class loading here.
486 // This also is critical in cases where the original thread gets stalled
487 // even in non-circularity situations.
488 // Note: only one thread can define the class, but multiple can resolve
489 // Note: must call resolve_super_or_fail even if null super -
490 // to force placeholder entry creation for this class for circularity detection
491 // Caller must check for pending exception
492 // Returns non-null klassOop if other thread has completed load
493 // and we are done,
494 // If return null klassOop and no pending exception, the caller must load the class
495 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
496 Symbol* name, Symbol* superclassname, Handle class_loader,
497 Handle protection_domain, Handle lockObject, TRAPS) {
498
499 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
500 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
501 int d_index = dictionary()->hash_to_index(d_hash);
502 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
503 int p_index = placeholders()->hash_to_index(p_hash);
504
505 // superk is not used, resolve_super called for circularity check only
506 // This code is reached in two situations. One if this thread
507 // is loading the same class twice (e.g. ClassCircularity, or
508 // java.lang.instrument).
509 // The second is if another thread started the resolve_super first
510 // and has not yet finished.
511 // In both cases the original caller will clean up the placeholder
512 // entry on error.
513 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
514 superclassname,
515 class_loader,
516 protection_domain,
517 true,
518 CHECK_(nh));
519 // We don't redefine the class, so we just need to clean up if there
520 // was not an error (don't want to modify any system dictionary
521 // data structures).
522 {
523 MutexLocker mu(SystemDictionary_lock, THREAD);
524 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
525 SystemDictionary_lock->notify_all();
526 }
527
528 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
529 // Serial class loaders and bootstrap classloader do wait for superclass loads
530 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
531 MutexLocker mu(SystemDictionary_lock, THREAD);
532 // Check if classloading completed while we were loading superclass or waiting
533 klassOop check = find_class(d_index, d_hash, name, class_loader);
534 if (check != NULL) {
535 // Klass is already loaded, so just return it
536 return(instanceKlassHandle(THREAD, check));
537 } else {
538 return nh;
539 }
540 }
541
542 // must loop to both handle other placeholder updates
543 // and spurious notifications
544 bool super_load_in_progress = true;
545 PlaceholderEntry* placeholder;
546 while (super_load_in_progress) {
547 MutexLocker mu(SystemDictionary_lock, THREAD);
548 // Check if classloading completed while we were loading superclass or waiting
549 klassOop check = find_class(d_index, d_hash, name, class_loader);
550 if (check != NULL) {
551 // Klass is already loaded, so just return it
552 return(instanceKlassHandle(THREAD, check));
553 } else {
554 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
555 if (placeholder && placeholder->super_load_in_progress() ){
556 // Before UnsyncloadClass:
557 // We only get here if the application has released the
558 // classloader lock when another thread was in the middle of loading a
559 // superclass/superinterface for this class, and now
560 // this thread is also trying to load this class.
561 // To minimize surprises, the first thread that started to
562 // load a class should be the one to complete the loading
563 // with the classfile it initially expected.
564 // This logic has the current thread wait once it has done
565 // all the superclass/superinterface loading it can, until
566 // the original thread completes the class loading or fails
567 // If it completes we will use the resulting instanceKlass
568 // which we will find below in the systemDictionary.
569 // We also get here for parallel bootstrap classloader
570 if (class_loader.is_null()) {
571 SystemDictionary_lock->wait();
572 } else {
573 double_lock_wait(lockObject, THREAD);
574 }
575 } else {
576 // If not in SD and not in PH, other thread's load must have failed
577 super_load_in_progress = false;
578 }
579 }
580 }
581 return (nh);
582 }
583
584
585 klassOop SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
586 assert(name != NULL && !FieldType::is_array(name) &&
587 !FieldType::is_obj(name), "invalid class name");
588
589 // UseNewReflection
590 // Fix for 4474172; see evaluation for more details
591 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
592
593 // Do lookup to see if class already exist and the protection domain
594 // has the right access
595 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
596 int d_index = dictionary()->hash_to_index(d_hash);
597 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
598 protection_domain, THREAD);
599 if (probe != NULL) return probe;
600
601
602 // Non-bootstrap class loaders will call out to class loader and
603 // define via jvm/jni_DefineClass which will acquire the
604 // class loader object lock to protect against multiple threads
605 // defining the class in parallel by accident.
606 // This lock must be acquired here so the waiter will find
607 // any successful result in the SystemDictionary and not attempt
608 // the define
609 // ParallelCapable Classloaders and the bootstrap classloader,
610 // or all classloaders with UnsyncloadClass do not acquire lock here
611 bool DoObjectLock = true;
612 if (is_parallelCapable(class_loader)) {
613 DoObjectLock = false;
614 }
615
616 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
617 int p_index = placeholders()->hash_to_index(p_hash);
618
619 // Class is not in SystemDictionary so we have to do loading.
620 // Make sure we are synchronized on the class loader before we proceed
621 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
622 check_loader_lock_contention(lockObject, THREAD);
623 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
624
625 // Check again (after locking) if class already exist in SystemDictionary
626 bool class_has_been_loaded = false;
627 bool super_load_in_progress = false;
628 bool havesupername = false;
629 instanceKlassHandle k;
630 PlaceholderEntry* placeholder;
631 Symbol* superclassname = NULL;
632
633 {
634 MutexLocker mu(SystemDictionary_lock, THREAD);
635 klassOop check = find_class(d_index, d_hash, name, class_loader);
636 if (check != NULL) {
637 // Klass is already loaded, so just return it
638 class_has_been_loaded = true;
639 k = instanceKlassHandle(THREAD, check);
640 } else {
641 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
642 if (placeholder && placeholder->super_load_in_progress()) {
643 super_load_in_progress = true;
644 if (placeholder->havesupername() == true) {
645 superclassname = placeholder->supername();
646 havesupername = true;
647 }
648 }
649 }
650 }
651
652 // If the class in is in the placeholder table, class loading is in progress
653 if (super_load_in_progress && havesupername==true) {
654 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
655 class_loader, protection_domain, lockObject, THREAD);
656 if (HAS_PENDING_EXCEPTION) {
657 return NULL;
658 }
659 if (!k.is_null()) {
660 class_has_been_loaded = true;
661 }
662 }
663
664 if (!class_has_been_loaded) {
665
666 // add placeholder entry to record loading instance class
667 // Five cases:
668 // All cases need to prevent modifying bootclasssearchpath
669 // in parallel with a classload of same classname
670 // Redefineclasses uses existence of the placeholder for the duration
671 // of the class load to prevent concurrent redefinition of not completely
672 // defined classes.
673 // case 1. traditional classloaders that rely on the classloader object lock
674 // - no other need for LOAD_INSTANCE
675 // case 2. traditional classloaders that break the classloader object lock
676 // as a deadlock workaround. Detection of this case requires that
677 // this check is done while holding the classloader object lock,
678 // and that lock is still held when calling classloader's loadClass.
679 // For these classloaders, we ensure that the first requestor
680 // completes the load and other requestors wait for completion.
681 // case 3. UnsyncloadClass - don't use objectLocker
682 // With this flag, we allow parallel classloading of a
683 // class/classloader pair
684 // case4. Bootstrap classloader - don't own objectLocker
685 // This classloader supports parallelism at the classloader level,
686 // but only allows a single load of a class/classloader pair.
687 // No performance benefit and no deadlock issues.
688 // case 5. parallelCapable user level classloaders - without objectLocker
689 // Allow parallel classloading of a class/classloader pair
690 bool throw_circularity_error = false;
691 {
692 MutexLocker mu(SystemDictionary_lock, THREAD);
693 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
694 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
695 if (oldprobe) {
696 // only need check_seen_thread once, not on each loop
697 // 6341374 java/lang/Instrument with -Xcomp
698 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
699 throw_circularity_error = true;
700 } else {
701 // case 1: traditional: should never see load_in_progress.
702 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
703
704 // case 4: bootstrap classloader: prevent futile classloading,
705 // wait on first requestor
706 if (class_loader.is_null()) {
707 SystemDictionary_lock->wait();
708 } else {
709 // case 2: traditional with broken classloader lock. wait on first
710 // requestor.
711 double_lock_wait(lockObject, THREAD);
712 }
713 // Check if classloading completed while we were waiting
714 klassOop check = find_class(d_index, d_hash, name, class_loader);
715 if (check != NULL) {
716 // Klass is already loaded, so just return it
717 k = instanceKlassHandle(THREAD, check);
718 class_has_been_loaded = true;
719 }
720 // check if other thread failed to load and cleaned up
721 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
722 }
723 }
724 }
725 }
726 // All cases: add LOAD_INSTANCE
727 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
728 // LOAD_INSTANCE in parallel
729 // add placeholder entry even if error - callers will remove on error
730 if (!throw_circularity_error && !class_has_been_loaded) {
731 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
732 // For class loaders that do not acquire the classloader object lock,
733 // if they did not catch another thread holding LOAD_INSTANCE,
734 // need a check analogous to the acquire ObjectLocker/find_class
735 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
736 // one final check if the load has already completed
737 // class loaders holding the ObjectLock shouldn't find the class here
738 klassOop check = find_class(d_index, d_hash, name, class_loader);
739 if (check != NULL) {
740 // Klass is already loaded, so just return it
741 k = instanceKlassHandle(THREAD, check);
742 class_has_been_loaded = true;
743 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
744 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
745 SystemDictionary_lock->notify_all();
746 }
747 }
748 }
749 // must throw error outside of owning lock
750 if (throw_circularity_error) {
751 ResourceMark rm(THREAD);
752 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
753 }
754
755 if (!class_has_been_loaded) {
756
757 // Do actual loading
758 k = load_instance_class(name, class_loader, THREAD);
759
760 // For UnsyncloadClass only
761 // If they got a linkageError, check if a parallel class load succeeded.
762 // If it did, then for bytecode resolution the specification requires
763 // that we return the same result we did for the other thread, i.e. the
764 // successfully loaded instanceKlass
765 // Should not get here for classloaders that support parallelism
766 // with the new cleaner mechanism, even with AllowParallelDefineClass
767 // Bootstrap goes through here to allow for an extra guarantee check
768 if (UnsyncloadClass || (class_loader.is_null())) {
769 if (k.is_null() && HAS_PENDING_EXCEPTION
770 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
771 MutexLocker mu(SystemDictionary_lock, THREAD);
772 klassOop check = find_class(d_index, d_hash, name, class_loader);
773 if (check != NULL) {
774 // Klass is already loaded, so just use it
775 k = instanceKlassHandle(THREAD, check);
776 CLEAR_PENDING_EXCEPTION;
777 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
778 }
779 }
780 }
781
782 // clean up placeholder entries for success or error
783 // This cleans up LOAD_INSTANCE entries
784 // It also cleans up LOAD_SUPER entries on errors from
785 // calling load_instance_class
786 {
787 MutexLocker mu(SystemDictionary_lock, THREAD);
788 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
789 if (probe != NULL) {
790 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
791 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
792 SystemDictionary_lock->notify_all();
793 }
794 }
795
796 // If everything was OK (no exceptions, no null return value), and
797 // class_loader is NOT the defining loader, do a little more bookkeeping.
798 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
799 k->class_loader() != class_loader()) {
800
801 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
802
803 // Need to check for a PENDING_EXCEPTION again; check_constraints
804 // can throw and doesn't use the CHECK macro.
805 if (!HAS_PENDING_EXCEPTION) {
806 { // Grabbing the Compile_lock prevents systemDictionary updates
807 // during compilations.
808 MutexLocker mu(Compile_lock, THREAD);
809 update_dictionary(d_index, d_hash, p_index, p_hash,
810 k, class_loader, THREAD);
811 }
812 if (JvmtiExport::should_post_class_load()) {
813 Thread *thread = THREAD;
814 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
815 JvmtiExport::post_class_load((JavaThread *) thread, k());
816 }
817 }
818 }
819 if (HAS_PENDING_EXCEPTION || k.is_null()) {
820 // On error, clean up placeholders
821 {
822 MutexLocker mu(SystemDictionary_lock, THREAD);
823 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
824 SystemDictionary_lock->notify_all();
825 }
826 return NULL;
827 }
828 }
829 }
830
831 #ifdef ASSERT
832 {
833 Handle loader (THREAD, k->class_loader());
834 MutexLocker mu(SystemDictionary_lock, THREAD);
835 oop kk = find_class(name, loader);
836 assert(kk == k(), "should be present in dictionary");
837 }
838 #endif
839
840 // return if the protection domain in NULL
841 if (protection_domain() == NULL) return k();
842
843 // Check the protection domain has the right access
844 {
845 MutexLocker mu(SystemDictionary_lock, THREAD);
846 // Note that we have an entry, and entries can be deleted only during GC,
847 // so we cannot allow GC to occur while we're holding this entry.
848 // We're using a No_Safepoint_Verifier to catch any place where we
849 // might potentially do a GC at all.
850 // SystemDictionary::do_unloading() asserts that classes are only
851 // unloaded at a safepoint.
852 No_Safepoint_Verifier nosafepoint;
853 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
854 class_loader,
855 protection_domain)) {
856 return k();
857 }
858 }
859
860 // Verify protection domain. If it fails an exception is thrown
861 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
862
863 return k();
864 }
865
866
867 // This routine does not lock the system dictionary.
868 //
869 // Since readers don't hold a lock, we must make sure that system
870 // dictionary entries are only removed at a safepoint (when only one
871 // thread is running), and are added to in a safe way (all links must
872 // be updated in an MT-safe manner).
873 //
874 // Callers should be aware that an entry could be added just after
875 // _dictionary->bucket(index) is read here, so the caller will not see
876 // the new entry.
877
878 klassOop SystemDictionary::find(Symbol* class_name,
879 Handle class_loader,
880 Handle protection_domain,
881 TRAPS) {
882
883 // UseNewReflection
884 // The result of this call should be consistent with the result
885 // of the call to resolve_instance_class_or_null().
886 // See evaluation 6790209 and 4474172 for more details.
887 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
888
889 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
890 int d_index = dictionary()->hash_to_index(d_hash);
891
892 {
893 // Note that we have an entry, and entries can be deleted only during GC,
894 // so we cannot allow GC to occur while we're holding this entry.
895 // We're using a No_Safepoint_Verifier to catch any place where we
896 // might potentially do a GC at all.
897 // SystemDictionary::do_unloading() asserts that classes are only
898 // unloaded at a safepoint.
899 No_Safepoint_Verifier nosafepoint;
900 return dictionary()->find(d_index, d_hash, class_name, class_loader,
901 protection_domain, THREAD);
902 }
903 }
904
905
906 // Look for a loaded instance or array klass by name. Do not do any loading.
907 // return NULL in case of error.
908 klassOop SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
909 Handle class_loader,
910 Handle protection_domain,
911 TRAPS) {
912 klassOop k = NULL;
913 assert(class_name != NULL, "class name must be non NULL");
914
915 // Try to get one of the well-known klasses.
916 if (LinkWellKnownClasses) {
917 k = find_well_known_klass(class_name);
918 if (k != NULL) {
919 return k;
920 }
921 }
922
923 if (FieldType::is_array(class_name)) {
924 // The name refers to an array. Parse the name.
925 // dimension and object_key in FieldArrayInfo are assigned as a
926 // side-effect of this call
927 FieldArrayInfo fd;
928 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
929 if (t != T_OBJECT) {
930 k = Universe::typeArrayKlassObj(t);
931 } else {
932 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
933 }
934 if (k != NULL) {
935 k = Klass::cast(k)->array_klass_or_null(fd.dimension());
936 }
937 } else {
938 k = find(class_name, class_loader, protection_domain, THREAD);
939 }
940 return k;
941 }
942
943 // Quick range check for names of well-known classes:
944 static Symbol* wk_klass_name_limits[2] = {NULL, NULL};
945
946 #ifndef PRODUCT
947 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
948 // counts for "hello world": 3983, 1616, 1075
949 // => 60% hit after limit guard, 25% total win rate
950 #endif
951
952 klassOop SystemDictionary::find_well_known_klass(Symbol* class_name) {
953 // A bounds-check on class_name will quickly get a negative result.
954 NOT_PRODUCT(find_wkk_calls++);
955 if (class_name >= wk_klass_name_limits[0] &&
956 class_name <= wk_klass_name_limits[1]) {
957 NOT_PRODUCT(find_wkk_probes++);
958 vmSymbols::SID sid = vmSymbols::find_sid(class_name);
959 if (sid != vmSymbols::NO_SID) {
960 klassOop k = NULL;
961 switch (sid) {
962 #define WK_KLASS_CASE(name, symbol, ignore_option) \
963 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
964 k = WK_KLASS(name); break;
965 WK_KLASSES_DO(WK_KLASS_CASE)
966 #undef WK_KLASS_CASE
967 }
968 NOT_PRODUCT(if (k != NULL) find_wkk_wins++);
969 return k;
970 }
971 }
972 return NULL;
973 }
974
975 // Note: this method is much like resolve_from_stream, but
976 // updates no supplemental data structures.
977 // TODO consolidate the two methods with a helper routine?
978 klassOop SystemDictionary::parse_stream(Symbol* class_name,
979 Handle class_loader,
980 Handle protection_domain,
981 ClassFileStream* st,
982 KlassHandle host_klass,
983 GrowableArray<Handle>* cp_patches,
984 TRAPS) {
985 TempNewSymbol parsed_name = NULL;
986
987 // Parse the stream. Note that we do this even though this klass might
988 // already be present in the SystemDictionary, otherwise we would not
989 // throw potential ClassFormatErrors.
990 //
991 // Note: "name" is updated.
992 // Further note: a placeholder will be added for this class when
993 // super classes are loaded (resolve_super_or_fail). We expect this
994 // to be called for all classes but java.lang.Object; and we preload
995 // java.lang.Object through resolve_or_fail, not this path.
996
997 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
998 class_loader,
999 protection_domain,
1000 host_klass,
1001 cp_patches,
1002 parsed_name,
1003 true,
1004 THREAD);
1005
1006 // We don't redefine the class, so we just need to clean up whether there
1007 // was an error or not (don't want to modify any system dictionary
1008 // data structures).
1009 // Parsed name could be null if we threw an error before we got far
1010 // enough along to parse it -- in that case, there is nothing to clean up.
1011 if (parsed_name != NULL) {
1012 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1013 class_loader);
1014 int p_index = placeholders()->hash_to_index(p_hash);
1015 {
1016 MutexLocker mu(SystemDictionary_lock, THREAD);
1017 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1018 SystemDictionary_lock->notify_all();
1019 }
1020 }
1021
1022 if (host_klass.not_null() && k.not_null()) {
1023 assert(EnableInvokeDynamic, "");
1024 // If it's anonymous, initialize it now, since nobody else will.
1025 k->set_host_klass(host_klass());
1026
1027 {
1028 MutexLocker mu_r(Compile_lock, THREAD);
1029
1030 // Add to class hierarchy, initialize vtables, and do possible
1031 // deoptimizations.
1032 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1033
1034 // But, do not add to system dictionary.
1035 }
1036
1037 k->eager_initialize(THREAD);
1038
1039 // notify jvmti
1040 if (JvmtiExport::should_post_class_load()) {
1041 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1042 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1043 }
1044 }
1045
1046 return k();
1047 }
1048
1049 // Add a klass to the system from a stream (called by jni_DefineClass and
1050 // JVM_DefineClass).
1051 // Note: class_name can be NULL. In that case we do not know the name of
1052 // the class until we have parsed the stream.
1053
1054 klassOop SystemDictionary::resolve_from_stream(Symbol* class_name,
1055 Handle class_loader,
1056 Handle protection_domain,
1057 ClassFileStream* st,
1058 bool verify,
1059 TRAPS) {
1060
1061 // Classloaders that support parallelism, e.g. bootstrap classloader,
1062 // or all classloaders with UnsyncloadClass do not acquire lock here
1063 bool DoObjectLock = true;
1064 if (is_parallelCapable(class_loader)) {
1065 DoObjectLock = false;
1066 }
1067
1068 // Make sure we are synchronized on the class loader before we proceed
1069 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1070 check_loader_lock_contention(lockObject, THREAD);
1071 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1072
1073 TempNewSymbol parsed_name = NULL;
1074
1075 // Parse the stream. Note that we do this even though this klass might
1076 // already be present in the SystemDictionary, otherwise we would not
1077 // throw potential ClassFormatErrors.
1078 //
1079 // Note: "name" is updated.
1080 // Further note: a placeholder will be added for this class when
1081 // super classes are loaded (resolve_super_or_fail). We expect this
1082 // to be called for all classes but java.lang.Object; and we preload
1083 // java.lang.Object through resolve_or_fail, not this path.
1084
1085 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1086 class_loader,
1087 protection_domain,
1088 parsed_name,
1089 verify,
1090 THREAD);
1091
1092 const char* pkg = "java/";
1093 if (!HAS_PENDING_EXCEPTION &&
1094 !class_loader.is_null() &&
1095 parsed_name != NULL &&
1096 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1097 // It is illegal to define classes in the "java." package from
1098 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1099 ResourceMark rm(THREAD);
1100 char* name = parsed_name->as_C_string();
1101 char* index = strrchr(name, '/');
1102 *index = '\0'; // chop to just the package name
1103 while ((index = strchr(name, '/')) != NULL) {
1104 *index = '.'; // replace '/' with '.' in package name
1105 }
1106 const char* fmt = "Prohibited package name: %s";
1107 size_t len = strlen(fmt) + strlen(name);
1108 char* message = NEW_RESOURCE_ARRAY(char, len);
1109 jio_snprintf(message, len, fmt, name);
1110 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1111 vmSymbols::java_lang_SecurityException(), message);
1112 }
1113
1114 if (!HAS_PENDING_EXCEPTION) {
1115 assert(parsed_name != NULL, "Sanity");
1116 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1117 // Verification prevents us from creating names with dots in them, this
1118 // asserts that that's the case.
1119 assert(is_internal_format(parsed_name),
1120 "external class name format used internally");
1121
1122 // Add class just loaded
1123 // If a class loader supports parallel classloading handle parallel define requests
1124 // find_or_define_instance_class may return a different instanceKlass
1125 if (is_parallelCapable(class_loader)) {
1126 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1127 } else {
1128 define_instance_class(k, THREAD);
1129 }
1130 }
1131
1132 // If parsing the class file or define_instance_class failed, we
1133 // need to remove the placeholder added on our behalf. But we
1134 // must make sure parsed_name is valid first (it won't be if we had
1135 // a format error before the class was parsed far enough to
1136 // find the name).
1137 if (HAS_PENDING_EXCEPTION && parsed_name != NULL) {
1138 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1139 class_loader);
1140 int p_index = placeholders()->hash_to_index(p_hash);
1141 {
1142 MutexLocker mu(SystemDictionary_lock, THREAD);
1143 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1144 SystemDictionary_lock->notify_all();
1145 }
1146 return NULL;
1147 }
1148
1149 // Make sure that we didn't leave a place holder in the
1150 // SystemDictionary; this is only done on success
1151 debug_only( {
1152 if (!HAS_PENDING_EXCEPTION) {
1153 assert(parsed_name != NULL, "parsed_name is still null?");
1154 Symbol* h_name = k->name();
1155 Handle h_loader (THREAD, k->class_loader());
1156
1157 MutexLocker mu(SystemDictionary_lock, THREAD);
1158
1159 klassOop check = find_class(parsed_name, class_loader);
1160 assert(check == k(), "should be present in the dictionary");
1161
1162 klassOop check2 = find_class(h_name, h_loader);
1163 assert(check == check2, "name inconsistancy in SystemDictionary");
1164 }
1165 } );
1166
1167 return k();
1168 }
1169
1170
1171 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1172 int number_of_entries) {
1173 assert(length == _nof_buckets * sizeof(HashtableBucket),
1174 "bad shared dictionary size.");
1175 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1176 }
1177
1178
1179 // If there is a shared dictionary, then find the entry for the
1180 // given shared system class, if any.
1181
1182 klassOop SystemDictionary::find_shared_class(Symbol* class_name) {
1183 if (shared_dictionary() != NULL) {
1184 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, Handle());
1185 int d_index = shared_dictionary()->hash_to_index(d_hash);
1186 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1187 } else {
1188 return NULL;
1189 }
1190 }
1191
1192
1193 // Load a class from the shared spaces (found through the shared system
1194 // dictionary). Force the superclass and all interfaces to be loaded.
1195 // Update the class definition to include sibling classes and no
1196 // subclasses (yet). [Classes in the shared space are not part of the
1197 // object hierarchy until loaded.]
1198
1199 instanceKlassHandle SystemDictionary::load_shared_class(
1200 Symbol* class_name, Handle class_loader, TRAPS) {
1201 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1202 return load_shared_class(ik, class_loader, THREAD);
1203 }
1204
1205 // Note well! Changes to this method may affect oop access order
1206 // in the shared archive. Please take care to not make changes that
1207 // adversely affect cold start time by changing the oop access order
1208 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1209 // MarkAndMoveOrderedReadWrite closures.
1210 instanceKlassHandle SystemDictionary::load_shared_class(
1211 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1212 assert(class_loader.is_null(), "non-null classloader for shared class?");
1213 if (ik.not_null()) {
1214 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1215 Symbol* class_name = ik->name();
1216
1217 // Found the class, now load the superclass and interfaces. If they
1218 // are shared, add them to the main system dictionary and reset
1219 // their hierarchy references (supers, subs, and interfaces).
1220
1221 if (ik->super() != NULL) {
1222 Symbol* cn = ik->super()->klass_part()->name();
1223 klassOop s = resolve_super_or_fail(class_name, cn,
1224 class_loader, Handle(), true, CHECK_(nh));
1225 if (s->klass_part() != ik->super()->klass_part()) {
1226 // The dynamically resolved super class is not the same as the one we used during dump time,
1227 // so we cannot use ik.
1228 return nh;
1229 }
1230 }
1231
1232 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1233 int num_interfaces = interfaces->length();
1234 for (int index = 0; index < num_interfaces; index++) {
1235 klassOop k = klassOop(interfaces->obj_at(index));
1236
1237 // Note: can not use instanceKlass::cast here because
1238 // interfaces' instanceKlass's C++ vtbls haven't been
1239 // reinitialized yet (they will be once the interface classes
1240 // are loaded)
1241 Symbol* name = k->klass_part()->name();
1242 klassOop i = resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1243 if (k->klass_part() != i->klass_part()) {
1244 // The dynamically resolved interface class is not the same as the one we used during dump time,
1245 // so we cannot use i.
1246 return nh;
1247 }
1248 }
1249
1250 // Adjust methods to recover missing data. They need addresses for
1251 // interpreter entry points and their default native method address
1252 // must be reset.
1253
1254 // Updating methods must be done under a lock so multiple
1255 // threads don't update these in parallel
1256 // Shared classes are all currently loaded by the bootstrap
1257 // classloader, so this will never cause a deadlock on
1258 // a custom class loader lock.
1259
1260 {
1261 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1262 check_loader_lock_contention(lockObject, THREAD);
1263 ObjectLocker ol(lockObject, THREAD, true);
1264
1265 objArrayHandle methods (THREAD, ik->methods());
1266 int num_methods = methods->length();
1267 for (int index2 = 0; index2 < num_methods; ++index2) {
1268 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1269 m()->link_method(m, CHECK_(nh));
1270 }
1271 if (JvmtiExport::has_redefined_a_class()) {
1272 // Reinitialize vtable because RedefineClasses may have changed some
1273 // entries in this vtable for super classes so the CDS vtable might
1274 // point to old or obsolete entries. RedefineClasses doesn't fix up
1275 // vtables in the shared system dictionary, only the main one.
1276 // It also redefines the itable too so fix that too.
1277 ResourceMark rm(THREAD);
1278 ik->vtable()->initialize_vtable(false, CHECK_(nh));
1279 ik->itable()->initialize_itable(false, CHECK_(nh));
1280 }
1281 }
1282
1283 if (TraceClassLoading) {
1284 ResourceMark rm;
1285 tty->print("[Loaded %s", ik->external_name());
1286 tty->print(" from shared objects file");
1287 tty->print_cr("]");
1288 }
1289 // notify a class loaded from shared object
1290 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1291 true /* shared class */);
1292 }
1293 return ik;
1294 }
1295
1296 #ifdef KERNEL
1297 // Some classes on the bootstrap class path haven't been installed on the
1298 // system yet. Call the DownloadManager method to make them appear in the
1299 // bootstrap class path and try again to load the named class.
1300 // Note that with delegation class loaders all classes in another loader will
1301 // first try to call this so it'd better be fast!!
1302 static instanceKlassHandle download_and_retry_class_load(
1303 Symbol* class_name,
1304 TRAPS) {
1305
1306 klassOop dlm = SystemDictionary::DownloadManager_klass();
1307 instanceKlassHandle nk;
1308
1309 // If download manager class isn't loaded just return.
1310 if (dlm == NULL) return nk;
1311
1312 { HandleMark hm(THREAD);
1313 ResourceMark rm(THREAD);
1314 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1315 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1316
1317 // return value
1318 JavaValue result(T_OBJECT);
1319
1320 // Call the DownloadManager. We assume that it has a lock because
1321 // multiple classes could be not found and downloaded at the same time.
1322 // class sun.misc.DownloadManager;
1323 // public static String getBootClassPathEntryForClass(String className);
1324 JavaCalls::call_static(&result,
1325 KlassHandle(THREAD, dlm),
1326 vmSymbols::getBootClassPathEntryForClass_name(),
1327 vmSymbols::string_string_signature(),
1328 class_string,
1329 CHECK_(nk));
1330
1331 // Get result.string and add to bootclasspath
1332 assert(result.get_type() == T_OBJECT, "just checking");
1333 oop obj = (oop) result.get_jobject();
1334 if (obj == NULL) { return nk; }
1335
1336 Handle h_obj(THREAD, obj);
1337 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1338 CHECK_(nk));
1339
1340 // lock the loader
1341 // we use this lock because JVMTI does.
1342 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1343
1344 ObjectLocker ol(loader_lock, THREAD);
1345 // add the file to the bootclasspath
1346 ClassLoader::update_class_path_entry_list(new_class_name, true);
1347 } // end HandleMark
1348
1349 if (TraceClassLoading) {
1350 ClassLoader::print_bootclasspath();
1351 }
1352 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1353 }
1354 #endif // KERNEL
1355
1356
1357 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1358 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1359 if (class_loader.is_null()) {
1360
1361 // Search the shared system dictionary for classes preloaded into the
1362 // shared spaces.
1363 instanceKlassHandle k;
1364 {
1365 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1366 k = load_shared_class(class_name, class_loader, THREAD);
1367 }
1368
1369 if (k.is_null()) {
1370 // Use VM class loader
1371 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1372 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1373 }
1374
1375 #ifdef KERNEL
1376 // If the VM class loader has failed to load the class, call the
1377 // DownloadManager class to make it magically appear on the classpath
1378 // and try again. This is only configured with the Kernel VM.
1379 if (k.is_null()) {
1380 k = download_and_retry_class_load(class_name, CHECK_(nh));
1381 }
1382 #endif // KERNEL
1383
1384 // find_or_define_instance_class may return a different instanceKlass
1385 if (!k.is_null()) {
1386 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1387 }
1388 return k;
1389 } else {
1390 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1391 ResourceMark rm(THREAD);
1392
1393 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1394 JavaThread* jt = (JavaThread*) THREAD;
1395
1396 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1397 ClassLoader::perf_app_classload_selftime(),
1398 ClassLoader::perf_app_classload_count(),
1399 jt->get_thread_stat()->perf_recursion_counts_addr(),
1400 jt->get_thread_stat()->perf_timers_addr(),
1401 PerfClassTraceTime::CLASS_LOAD);
1402
1403 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1404 // Translate to external class name format, i.e., convert '/' chars to '.'
1405 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1406
1407 JavaValue result(T_OBJECT);
1408
1409 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1410
1411 // Call public unsynchronized loadClass(String) directly for all class loaders
1412 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1413 // acquire a class-name based lock rather than the class loader object lock.
1414 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1415 // so the call to loadClassInternal() was not required.
1416 //
1417 // UnsyncloadClass flag means both call loadClass(String) and do
1418 // not acquire the class loader lock even for class loaders that are
1419 // not parallelCapable. This was a risky transitional
1420 // flag for diagnostic purposes only. It is risky to call
1421 // custom class loaders without synchronization.
1422 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1423 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1424 // Do NOT assume this will be supported in future releases.
1425 //
1426 // Added MustCallLoadClassInternal in case we discover in the field
1427 // a customer that counts on this call
1428 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1429 JavaCalls::call_special(&result,
1430 class_loader,
1431 spec_klass,
1432 vmSymbols::loadClassInternal_name(),
1433 vmSymbols::string_class_signature(),
1434 string,
1435 CHECK_(nh));
1436 } else {
1437 JavaCalls::call_virtual(&result,
1438 class_loader,
1439 spec_klass,
1440 vmSymbols::loadClass_name(),
1441 vmSymbols::string_class_signature(),
1442 string,
1443 CHECK_(nh));
1444 }
1445
1446 assert(result.get_type() == T_OBJECT, "just checking");
1447 oop obj = (oop) result.get_jobject();
1448
1449 // Primitive classes return null since forName() can not be
1450 // used to obtain any of the Class objects representing primitives or void
1451 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1452 instanceKlassHandle k =
1453 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1454 // For user defined Java class loaders, check that the name returned is
1455 // the same as that requested. This check is done for the bootstrap
1456 // loader when parsing the class file.
1457 if (class_name == k->name()) {
1458 return k;
1459 }
1460 }
1461 // Class is not found or has the wrong name, return NULL
1462 return nh;
1463 }
1464 }
1465
1466 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1467
1468 Handle class_loader_h(THREAD, k->class_loader());
1469
1470 // for bootstrap and other parallel classloaders don't acquire lock,
1471 // use placeholder token
1472 // If a parallelCapable class loader calls define_instance_class instead of
1473 // find_or_define_instance_class to get here, we have a timing
1474 // hole with systemDictionary updates and check_constraints
1475 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1476 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1477 compute_loader_lock_object(class_loader_h, THREAD)),
1478 "define called without lock");
1479 }
1480
1481 // Check class-loading constraints. Throw exception if violation is detected.
1482 // Grabs and releases SystemDictionary_lock
1483 // The check_constraints/find_class call and update_dictionary sequence
1484 // must be "atomic" for a specific class/classloader pair so we never
1485 // define two different instanceKlasses for that class/classloader pair.
1486 // Existing classloaders will call define_instance_class with the
1487 // classloader lock held
1488 // Parallel classloaders will call find_or_define_instance_class
1489 // which will require a token to perform the define class
1490 Symbol* name_h = k->name();
1491 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1492 int d_index = dictionary()->hash_to_index(d_hash);
1493 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1494
1495 // Register class just loaded with class loader (placed in Vector)
1496 // Note we do this before updating the dictionary, as this can
1497 // fail with an OutOfMemoryError (if it does, we will *not* put this
1498 // class in the dictionary and will not update the class hierarchy).
1499 if (k->class_loader() != NULL) {
1500 methodHandle m(THREAD, Universe::loader_addClass_method());
1501 JavaValue result(T_VOID);
1502 JavaCallArguments args(class_loader_h);
1503 args.push_oop(Handle(THREAD, k->java_mirror()));
1504 JavaCalls::call(&result, m, &args, CHECK);
1505 }
1506
1507 // Add the new class. We need recompile lock during update of CHA.
1508 {
1509 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1510 int p_index = placeholders()->hash_to_index(p_hash);
1511
1512 MutexLocker mu_r(Compile_lock, THREAD);
1513
1514 // Add to class hierarchy, initialize vtables, and do possible
1515 // deoptimizations.
1516 add_to_hierarchy(k, CHECK); // No exception, but can block
1517
1518 // Add to systemDictionary - so other classes can see it.
1519 // Grabs and releases SystemDictionary_lock
1520 update_dictionary(d_index, d_hash, p_index, p_hash,
1521 k, class_loader_h, THREAD);
1522 }
1523 k->eager_initialize(THREAD);
1524
1525 // notify jvmti
1526 if (JvmtiExport::should_post_class_load()) {
1527 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1528 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1529
1530 }
1531 }
1532
1533 // Support parallel classloading
1534 // All parallel class loaders, including bootstrap classloader
1535 // lock a placeholder entry for this class/class_loader pair
1536 // to allow parallel defines of different classes for this class loader
1537 // With AllowParallelDefine flag==true, in case they do not synchronize around
1538 // FindLoadedClass/DefineClass, calls, we check for parallel
1539 // loading for them, wait if a defineClass is in progress
1540 // and return the initial requestor's results
1541 // This flag does not apply to the bootstrap classloader.
1542 // With AllowParallelDefine flag==false, call through to define_instance_class
1543 // which will throw LinkageError: duplicate class definition.
1544 // False is the requested default.
1545 // For better performance, the class loaders should synchronize
1546 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1547 // potentially waste time reading and parsing the bytestream.
1548 // Note: VM callers should ensure consistency of k/class_name,class_loader
1549 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1550
1551 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1552 Symbol* name_h = k->name(); // passed in class_name may be null
1553
1554 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader);
1555 int d_index = dictionary()->hash_to_index(d_hash);
1556
1557 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1558 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader);
1559 int p_index = placeholders()->hash_to_index(p_hash);
1560 PlaceholderEntry* probe;
1561
1562 {
1563 MutexLocker mu(SystemDictionary_lock, THREAD);
1564 // First check if class already defined
1565 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1566 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1567 if (check != NULL) {
1568 return(instanceKlassHandle(THREAD, check));
1569 }
1570 }
1571
1572 // Acquire define token for this class/classloader
1573 probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1574 // Wait if another thread defining in parallel
1575 // All threads wait - even those that will throw duplicate class: otherwise
1576 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1577 // if other thread has not finished updating dictionary
1578 while (probe->definer() != NULL) {
1579 SystemDictionary_lock->wait();
1580 }
1581 // Only special cases allow parallel defines and can use other thread's results
1582 // Other cases fall through, and may run into duplicate defines
1583 // caught by finding an entry in the SystemDictionary
1584 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) {
1585 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1586 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1587 SystemDictionary_lock->notify_all();
1588 #ifdef ASSERT
1589 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1590 assert(check != NULL, "definer missed recording success");
1591 #endif
1592 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1593 } else {
1594 // This thread will define the class (even if earlier thread tried and had an error)
1595 probe->set_definer(THREAD);
1596 }
1597 }
1598
1599 define_instance_class(k, THREAD);
1600
1601 Handle linkage_exception = Handle(); // null handle
1602
1603 // definer must notify any waiting threads
1604 {
1605 MutexLocker mu(SystemDictionary_lock, THREAD);
1606 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader);
1607 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1608 if (probe != NULL) {
1609 if (HAS_PENDING_EXCEPTION) {
1610 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1611 CLEAR_PENDING_EXCEPTION;
1612 } else {
1613 probe->set_instanceKlass(k());
1614 }
1615 probe->set_definer(NULL);
1616 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1617 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1618 SystemDictionary_lock->notify_all();
1619 }
1620 }
1621
1622 // Can't throw exception while holding lock due to rank ordering
1623 if (linkage_exception() != NULL) {
1624 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1625 }
1626
1627 return k;
1628 }
1629 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1630 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1631 if (class_loader.is_null()) {
1632 return Handle(THREAD, _system_loader_lock_obj);
1633 } else {
1634 return class_loader;
1635 }
1636 }
1637
1638 // This method is added to check how often we have to wait to grab loader
1639 // lock. The results are being recorded in the performance counters defined in
1640 // ClassLoader::_sync_systemLoaderLockContentionRate and
1641 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1642 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1643 if (!UsePerfData) {
1644 return;
1645 }
1646
1647 assert(!loader_lock.is_null(), "NULL lock object");
1648
1649 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1650 == ObjectSynchronizer::owner_other) {
1651 // contention will likely happen, so increment the corresponding
1652 // contention counter.
1653 if (loader_lock() == _system_loader_lock_obj) {
1654 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1655 } else {
1656 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1657 }
1658 }
1659 }
1660
1661 // ----------------------------------------------------------------------------
1662 // Lookup
1663
1664 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1665 Symbol* class_name,
1666 Handle class_loader) {
1667 assert_locked_or_safepoint(SystemDictionary_lock);
1668 assert (index == dictionary()->index_for(class_name, class_loader),
1669 "incorrect index?");
1670
1671 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1672 return k;
1673 }
1674
1675
1676 // Basic find on classes in the midst of being loaded
1677 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1678 Handle class_loader) {
1679 assert_locked_or_safepoint(SystemDictionary_lock);
1680 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1681 int p_index = placeholders()->hash_to_index(p_hash);
1682 return placeholders()->find_entry(p_index, p_hash, class_name, class_loader);
1683 }
1684
1685
1686 // Used for assertions and verification only
1687 klassOop SystemDictionary::find_class(Symbol* class_name, Handle class_loader) {
1688 #ifndef ASSERT
1689 guarantee(VerifyBeforeGC ||
1690 VerifyDuringGC ||
1691 VerifyBeforeExit ||
1692 VerifyAfterGC, "too expensive");
1693 #endif
1694 assert_locked_or_safepoint(SystemDictionary_lock);
1695
1696 // First look in the loaded class array
1697 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1698 int d_index = dictionary()->hash_to_index(d_hash);
1699 return find_class(d_index, d_hash, class_name, class_loader);
1700 }
1701
1702
1703 // Get the next class in the diictionary.
1704 klassOop SystemDictionary::try_get_next_class() {
1705 return dictionary()->try_get_next_class();
1706 }
1707
1708
1709 // ----------------------------------------------------------------------------
1710 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1711 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1712 // before a new class is used.
1713
1714 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1715 assert(k.not_null(), "just checking");
1716 assert_locked_or_safepoint(Compile_lock);
1717
1718 // Link into hierachy. Make sure the vtables are initialized before linking into
1719 k->append_to_sibling_list(); // add to superklass/sibling list
1720 k->process_interfaces(THREAD); // handle all "implements" declarations
1721 k->set_init_state(instanceKlass::loaded);
1722 // Now flush all code that depended on old class hierarchy.
1723 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1724 // Also, first reinitialize vtable because it may have gotten out of synch
1725 // while the new class wasn't connected to the class hierarchy.
1726 Universe::flush_dependents_on(k);
1727 }
1728
1729
1730 // ----------------------------------------------------------------------------
1731 // GC support
1732
1733 // Following roots during mark-sweep is separated in two phases.
1734 //
1735 // The first phase follows preloaded classes and all other system
1736 // classes, since these will never get unloaded anyway.
1737 //
1738 // The second phase removes (unloads) unreachable classes from the
1739 // system dictionary and follows the remaining classes' contents.
1740
1741 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1742 // Follow preloaded classes/mirrors and system loader object
1743 blk->do_oop(&_java_system_loader);
1744 preloaded_oops_do(blk);
1745 always_strong_classes_do(blk);
1746 }
1747
1748
1749 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1750 // Follow all system classes and temporary placeholders in dictionary
1751 dictionary()->always_strong_classes_do(blk);
1752
1753 // Placeholders. These are *always* strong roots, as they
1754 // represent classes we're actively loading.
1755 placeholders_do(blk);
1756
1757 // Visit extra methods
1758 invoke_method_table()->oops_do(blk);
1759 }
1760
1761
1762 void SystemDictionary::placeholders_do(OopClosure* blk) {
1763 placeholders()->oops_do(blk);
1764 }
1765
1766 // Calculate a "good" systemdictionary size based
1767 // on predicted or current loaded classes count
1768 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1769 int newsize = _old_default_sdsize;
1770 if ((classcount > 0) && !DumpSharedSpaces) {
1771 int desiredsize = classcount/_average_depth_goal;
1772 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1773 newsize = _primelist[++_sdgeneration]) {
1774 if (desiredsize <= newsize) {
1775 break;
1776 }
1777 }
1778 }
1779 return newsize;
1780 }
1781 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1782 bool result = dictionary()->do_unloading(is_alive);
1783 constraints()->purge_loader_constraints(is_alive);
1784 resolution_errors()->purge_resolution_errors(is_alive);
1785 return result;
1786 }
1787
1788
1789 // The mirrors are scanned by shared_oops_do() which is
1790 // not called by oops_do(). In order to process oops in
1791 // a necessary order, shared_oops_do() is call by
1792 // Universe::oops_do().
1793 void SystemDictionary::oops_do(OopClosure* f) {
1794 // Adjust preloaded classes and system loader object
1795 f->do_oop(&_java_system_loader);
1796 preloaded_oops_do(f);
1797
1798 lazily_loaded_oops_do(f);
1799
1800 // Adjust dictionary
1801 dictionary()->oops_do(f);
1802
1803 // Visit extra methods
1804 invoke_method_table()->oops_do(f);
1805
1806 // Partially loaded classes
1807 placeholders()->oops_do(f);
1808
1809 // Adjust constraint table
1810 constraints()->oops_do(f);
1811
1812 // Adjust resolution error table
1813 resolution_errors()->oops_do(f);
1814 }
1815
1816
1817 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1818 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1819 f->do_oop((oop*) &_well_known_klasses[k]);
1820 }
1821
1822 {
1823 for (int i = 0; i < T_VOID+1; i++) {
1824 if (_box_klasses[i] != NULL) {
1825 assert(i >= T_BOOLEAN, "checking");
1826 f->do_oop((oop*) &_box_klasses[i]);
1827 }
1828 }
1829 }
1830
1831 // The basic type mirrors would have already been processed in
1832 // Universe::oops_do(), via a call to shared_oops_do(), so should
1833 // not be processed again.
1834
1835 f->do_oop((oop*) &_system_loader_lock_obj);
1836 FilteredFieldsMap::klasses_oops_do(f);
1837 }
1838
1839 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1840 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1841 }
1842
1843 // Just the classes from defining class loaders
1844 // Don't iterate over placeholders
1845 void SystemDictionary::classes_do(void f(klassOop)) {
1846 dictionary()->classes_do(f);
1847 }
1848
1849 // Added for initialize_itable_for_klass
1850 // Just the classes from defining class loaders
1851 // Don't iterate over placeholders
1852 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1853 dictionary()->classes_do(f, CHECK);
1854 }
1855
1856 // All classes, and their class loaders
1857 // Don't iterate over placeholders
1858 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1859 dictionary()->classes_do(f);
1860 }
1861
1862 // All classes, and their class loaders
1863 // (added for helpers that use HandleMarks and ResourceMarks)
1864 // Don't iterate over placeholders
1865 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1866 dictionary()->classes_do(f, CHECK);
1867 }
1868
1869 void SystemDictionary::placeholders_do(void f(Symbol*, oop)) {
1870 placeholders()->entries_do(f);
1871 }
1872
1873 void SystemDictionary::methods_do(void f(methodOop)) {
1874 dictionary()->methods_do(f);
1875 invoke_method_table()->methods_do(f);
1876 }
1877
1878 // ----------------------------------------------------------------------------
1879 // Lazily load klasses
1880
1881 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1882 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1883
1884 // if multiple threads calling this function, only one thread will load
1885 // the class. The other threads will find the loaded version once the
1886 // class is loaded.
1887 klassOop aos = _abstract_ownable_synchronizer_klass;
1888 if (aos == NULL) {
1889 klassOop k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1890 // Force a fence to prevent any read before the write completes
1891 OrderAccess::fence();
1892 _abstract_ownable_synchronizer_klass = k;
1893 }
1894 }
1895
1896 // ----------------------------------------------------------------------------
1897 // Initialization
1898
1899 void SystemDictionary::initialize(TRAPS) {
1900 // Allocate arrays
1901 assert(dictionary() == NULL,
1902 "SystemDictionary should only be initialized once");
1903 _sdgeneration = 0;
1904 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1905 _placeholders = new PlaceholderTable(_nof_buckets);
1906 _number_of_modifications = 0;
1907 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1908 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1909 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1910
1911 // Allocate private object used as system class loader lock
1912 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1913 // Initialize basic classes
1914 initialize_preloaded_classes(CHECK);
1915 }
1916
1917 // Compact table of directions on the initialization of klasses:
1918 static const short wk_init_info[] = {
1919 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1920 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1921 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1922 | (int)SystemDictionary::option ),
1923 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1924 #undef WK_KLASS_INIT_INFO
1925 0
1926 };
1927
1928 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1929 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1930 int info = wk_init_info[id - FIRST_WKID];
1931 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1932 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1933 klassOop* klassp = &_well_known_klasses[id];
1934 bool must_load = (init_opt < SystemDictionary::Opt);
1935 bool try_load = true;
1936 if (init_opt == SystemDictionary::Opt_Kernel) {
1937 #ifndef KERNEL
1938 try_load = false;
1939 #endif //KERNEL
1940 }
1941 if ((*klassp) == NULL && try_load) {
1942 if (must_load) {
1943 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1944 } else {
1945 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1946 }
1947 }
1948 return ((*klassp) != NULL);
1949 }
1950
1951 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1952 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1953 for (int id = (int)start_id; id < (int)limit_id; id++) {
1954 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1955 int info = wk_init_info[id - FIRST_WKID];
1956 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1957 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1958
1959 initialize_wk_klass((WKID)id, opt, CHECK);
1960
1961 // Update limits, so find_well_known_klass can be very fast:
1962 Symbol* s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1963 if (wk_klass_name_limits[1] == NULL) {
1964 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1965 } else if (wk_klass_name_limits[1] < s) {
1966 wk_klass_name_limits[1] = s;
1967 } else if (wk_klass_name_limits[0] > s) {
1968 wk_klass_name_limits[0] = s;
1969 }
1970 }
1971
1972 // move the starting value forward to the limit:
1973 start_id = limit_id;
1974 }
1975
1976
1977 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1978 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1979 // Preload commonly used klasses
1980 WKID scan = FIRST_WKID;
1981 // first do Object, String, Class
1982 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1983
1984 // Calculate offsets for String and Class classes since they are loaded and
1985 // can be used after this point.
1986 java_lang_String::compute_offsets();
1987 java_lang_Class::compute_offsets();
1988
1989 // Fixup mirrors for classes loaded before java.lang.Class.
1990 // These calls iterate over the objects currently in the perm gen
1991 // so calling them at this point is matters (not before when there
1992 // are fewer objects and not later after there are more objects
1993 // in the perm gen.
1994 Universe::initialize_basic_type_mirrors(CHECK);
1995 Universe::fixup_mirrors(CHECK);
1996
1997 // do a bunch more:
1998 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1999
2000 // Preload ref klasses and set reference types
2001 instanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2002 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2003
2004 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
2005 instanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2006 instanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2007 instanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2008 instanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2009 instanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
2010
2011 // JSR 292 classes
2012 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2013 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2014 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2015 if (EnableInvokeDynamic) {
2016 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2017 } else {
2018 // Skip the JSR 292 classes, if not enabled.
2019 scan = WKID(jsr292_group_end + 1);
2020 }
2021
2022 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
2023
2024 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2025 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2026 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2027 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2028 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2029 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2030 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2031 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2032 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2033 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2034
2035 #ifdef KERNEL
2036 if (DownloadManager_klass() == NULL) {
2037 warning("Cannot find sun/jkernel/DownloadManager");
2038 }
2039 #endif // KERNEL
2040
2041 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2042 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2043 _has_loadClassInternal = (method != NULL);
2044 }
2045 { // Compute whether we should use checkPackageAccess or NOT
2046 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2047 _has_checkPackageAccess = (method != NULL);
2048 }
2049 }
2050
2051 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2052 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2053 BasicType SystemDictionary::box_klass_type(klassOop k) {
2054 assert(k != NULL, "");
2055 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2056 if (_box_klasses[i] == k)
2057 return (BasicType)i;
2058 }
2059 return T_OBJECT;
2060 }
2061
2062 KlassHandle SystemDictionaryHandles::box_klass(BasicType t) {
2063 if (t >= T_BOOLEAN && t <= T_VOID)
2064 return KlassHandle(&SystemDictionary::_box_klasses[t], true);
2065 else
2066 return KlassHandle();
2067 }
2068
2069 // Constraints on class loaders. The details of the algorithm can be
2070 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2071 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2072 // that the system dictionary needs to maintain a set of contraints that
2073 // must be satisfied by all classes in the dictionary.
2074 // if defining is true, then LinkageError if already in systemDictionary
2075 // if initiating loader, then ok if instanceKlass matches existing entry
2076
2077 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2078 instanceKlassHandle k,
2079 Handle class_loader, bool defining,
2080 TRAPS) {
2081 const char *linkage_error = NULL;
2082 {
2083 Symbol* name = k->name();
2084 MutexLocker mu(SystemDictionary_lock, THREAD);
2085
2086 klassOop check = find_class(d_index, d_hash, name, class_loader);
2087 if (check != (klassOop)NULL) {
2088 // if different instanceKlass - duplicate class definition,
2089 // else - ok, class loaded by a different thread in parallel,
2090 // we should only have found it if it was done loading and ok to use
2091 // system dictionary only holds instance classes, placeholders
2092 // also holds array classes
2093
2094 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2095 if ((defining == true) || (k() != check)) {
2096 linkage_error = "loader (instance of %s): attempted duplicate class "
2097 "definition for name: \"%s\"";
2098 } else {
2099 return;
2100 }
2101 }
2102
2103 #ifdef ASSERT
2104 Symbol* ph_check = find_placeholder(name, class_loader);
2105 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2106 #endif
2107
2108 if (linkage_error == NULL) {
2109 if (constraints()->check_or_update(k, class_loader, name) == false) {
2110 linkage_error = "loader constraint violation: loader (instance of %s)"
2111 " previously initiated loading for a different type with name \"%s\"";
2112 }
2113 }
2114 }
2115
2116 // Throw error now if needed (cannot throw while holding
2117 // SystemDictionary_lock because of rank ordering)
2118
2119 if (linkage_error) {
2120 ResourceMark rm(THREAD);
2121 const char* class_loader_name = loader_name(class_loader());
2122 char* type_name = k->name()->as_C_string();
2123 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2124 strlen(type_name);
2125 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2126 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2127 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2128 }
2129 }
2130
2131
2132 // Update system dictionary - done after check_constraint and add_to_hierachy
2133 // have been called.
2134 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2135 int p_index, unsigned int p_hash,
2136 instanceKlassHandle k,
2137 Handle class_loader,
2138 TRAPS) {
2139 // Compile_lock prevents systemDictionary updates during compilations
2140 assert_locked_or_safepoint(Compile_lock);
2141 Symbol* name = k->name();
2142
2143 {
2144 MutexLocker mu1(SystemDictionary_lock, THREAD);
2145
2146 // See whether biased locking is enabled and if so set it for this
2147 // klass.
2148 // Note that this must be done past the last potential blocking
2149 // point / safepoint. We enable biased locking lazily using a
2150 // VM_Operation to iterate the SystemDictionary and installing the
2151 // biasable mark word into each instanceKlass's prototype header.
2152 // To avoid race conditions where we accidentally miss enabling the
2153 // optimization for one class in the process of being added to the
2154 // dictionary, we must not safepoint after the test of
2155 // BiasedLocking::enabled().
2156 if (UseBiasedLocking && BiasedLocking::enabled()) {
2157 // Set biased locking bit for all loaded classes; it will be
2158 // cleared if revocation occurs too often for this type
2159 // NOTE that we must only do this when the class is initally
2160 // defined, not each time it is referenced from a new class loader
2161 if (k->class_loader() == class_loader()) {
2162 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2163 }
2164 }
2165
2166 // Assign a classid if one has not already been assigned. The
2167 // counter does not need to be atomically incremented since this
2168 // is only done while holding the SystemDictionary_lock.
2169 // All loaded classes get a unique ID.
2170 TRACE_INIT_ID(k);
2171
2172 // Check for a placeholder. If there, remove it and make a
2173 // new system dictionary entry.
2174 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2175 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2176 if (sd_check == NULL) {
2177 dictionary()->add_klass(name, class_loader, k);
2178 notice_modification();
2179 }
2180 #ifdef ASSERT
2181 sd_check = find_class(d_index, d_hash, name, class_loader);
2182 assert (sd_check != NULL, "should have entry in system dictionary");
2183 // Changed to allow PH to remain to complete class circularity checking
2184 // while only one thread can define a class at one time, multiple
2185 // classes can resolve the superclass for a class at one time,
2186 // and the placeholder is used to track that
2187 // Symbol* ph_check = find_placeholder(name, class_loader);
2188 // assert (ph_check == NULL, "should not have a placeholder entry");
2189 #endif
2190 SystemDictionary_lock->notify_all();
2191 }
2192 }
2193
2194
2195 // Try to find a class name using the loader constraints. The
2196 // loader constraints might know about a class that isn't fully loaded
2197 // yet and these will be ignored.
2198 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2199 Symbol* class_name, Handle class_loader, TRAPS) {
2200
2201 // First see if it has been loaded directly.
2202 // Force the protection domain to be null. (This removes protection checks.)
2203 Handle no_protection_domain;
2204 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2205 no_protection_domain, CHECK_NULL);
2206 if (klass != NULL)
2207 return klass;
2208
2209 // Now look to see if it has been loaded elsewhere, and is subject to
2210 // a loader constraint that would require this loader to return the
2211 // klass that is already loaded.
2212 if (FieldType::is_array(class_name)) {
2213 // For array classes, their klassOops are not kept in the
2214 // constraint table. The element klassOops are.
2215 FieldArrayInfo fd;
2216 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2217 if (t != T_OBJECT) {
2218 klass = Universe::typeArrayKlassObj(t);
2219 } else {
2220 MutexLocker mu(SystemDictionary_lock, THREAD);
2221 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2222 }
2223 // If element class already loaded, allocate array klass
2224 if (klass != NULL) {
2225 klass = Klass::cast(klass)->array_klass_or_null(fd.dimension());
2226 }
2227 } else {
2228 MutexLocker mu(SystemDictionary_lock, THREAD);
2229 // Non-array classes are easy: simply check the constraint table.
2230 klass = constraints()->find_constrained_klass(class_name, class_loader);
2231 }
2232
2233 return klass;
2234 }
2235
2236
2237 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2238 Handle class_loader1,
2239 Handle class_loader2,
2240 Thread* THREAD) {
2241 Symbol* constraint_name = NULL;
2242 if (!FieldType::is_array(class_name)) {
2243 constraint_name = class_name;
2244 } else {
2245 // For array classes, their klassOops are not kept in the
2246 // constraint table. The element classes are.
2247 FieldArrayInfo fd;
2248 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2249 // primitive types always pass
2250 if (t != T_OBJECT) {
2251 return true;
2252 } else {
2253 constraint_name = fd.object_key();
2254 }
2255 }
2256 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, class_loader1);
2257 int d_index1 = dictionary()->hash_to_index(d_hash1);
2258
2259 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, class_loader2);
2260 int d_index2 = dictionary()->hash_to_index(d_hash2);
2261 {
2262 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2263
2264 // Better never do a GC while we're holding these oops
2265 No_Safepoint_Verifier nosafepoint;
2266
2267 klassOop klass1 = find_class(d_index1, d_hash1, constraint_name, class_loader1);
2268 klassOop klass2 = find_class(d_index2, d_hash2, constraint_name, class_loader2);
2269 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2270 klass2, class_loader2);
2271 }
2272 }
2273
2274 // Add entry to resolution error table to record the error when the first
2275 // attempt to resolve a reference to a class has failed.
2276 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2277 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2278 int index = resolution_errors()->hash_to_index(hash);
2279 {
2280 MutexLocker ml(SystemDictionary_lock, Thread::current());
2281 resolution_errors()->add_entry(index, hash, pool, which, error);
2282 }
2283 }
2284
2285 // Lookup resolution error table. Returns error if found, otherwise NULL.
2286 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2287 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2288 int index = resolution_errors()->hash_to_index(hash);
2289 {
2290 MutexLocker ml(SystemDictionary_lock, Thread::current());
2291 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2292 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2293 }
2294 }
2295
2296
2297 // Signature constraints ensure that callers and callees agree about
2298 // the meaning of type names in their signatures. This routine is the
2299 // intake for constraints. It collects them from several places:
2300 //
2301 // * LinkResolver::resolve_method (if check_access is true) requires
2302 // that the resolving class (the caller) and the defining class of
2303 // the resolved method (the callee) agree on each type in the
2304 // method's signature.
2305 //
2306 // * LinkResolver::resolve_interface_method performs exactly the same
2307 // checks.
2308 //
2309 // * LinkResolver::resolve_field requires that the constant pool
2310 // attempting to link to a field agree with the field's defining
2311 // class about the type of the field signature.
2312 //
2313 // * klassVtable::initialize_vtable requires that, when a class
2314 // overrides a vtable entry allocated by a superclass, that the
2315 // overriding method (i.e., the callee) agree with the superclass
2316 // on each type in the method's signature.
2317 //
2318 // * klassItable::initialize_itable requires that, when a class fills
2319 // in its itables, for each non-abstract method installed in an
2320 // itable, the method (i.e., the callee) agree with the interface
2321 // on each type in the method's signature.
2322 //
2323 // All those methods have a boolean (check_access, checkconstraints)
2324 // which turns off the checks. This is used from specialized contexts
2325 // such as bootstrapping, dumping, and debugging.
2326 //
2327 // No direct constraint is placed between the class and its
2328 // supertypes. Constraints are only placed along linked relations
2329 // between callers and callees. When a method overrides or implements
2330 // an abstract method in a supertype (superclass or interface), the
2331 // constraints are placed as if the supertype were the caller to the
2332 // overriding method. (This works well, since callers to the
2333 // supertype have already established agreement between themselves and
2334 // the supertype.) As a result of all this, a class can disagree with
2335 // its supertype about the meaning of a type name, as long as that
2336 // class neither calls a relevant method of the supertype, nor is
2337 // called (perhaps via an override) from the supertype.
2338 //
2339 //
2340 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2341 //
2342 // Make sure all class components (including arrays) in the given
2343 // signature will be resolved to the same class in both loaders.
2344 // Returns the name of the type that failed a loader constraint check, or
2345 // NULL if no constraint failed. The returned C string needs cleaning up
2346 // with a ResourceMark in the caller. No exception except OOME is thrown.
2347 // Arrays are not added to the loader constraint table, their elements are.
2348 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2349 Handle loader1, Handle loader2,
2350 bool is_method, TRAPS) {
2351 // Nothing to do if loaders are the same.
2352 if (loader1() == loader2()) {
2353 return NULL;
2354 }
2355
2356 ResourceMark rm(THREAD);
2357 SignatureStream sig_strm(signature, is_method);
2358 while (!sig_strm.is_done()) {
2359 if (sig_strm.is_object()) {
2360 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2361 Symbol* sig = s;
2362 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2363 return sig->as_C_string();
2364 }
2365 }
2366 sig_strm.next();
2367 }
2368 return NULL;
2369 }
2370
2371 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2372 // We must ensure that all class loaders everywhere will reach this class, for any client.
2373 // This is a safe bet for public classes in java.lang, such as Object and String.
2374 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2375 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2376 static bool is_always_visible_class(oop mirror) {
2377 klassOop klass = java_lang_Class::as_klassOop(mirror);
2378 if (Klass::cast(klass)->oop_is_objArray()) {
2379 klass = objArrayKlass::cast(klass)->bottom_klass(); // check element type
2380 }
2381 if (Klass::cast(klass)->oop_is_typeArray()) {
2382 return true; // primitive array
2383 }
2384 assert(Klass::cast(klass)->oop_is_instance(), Klass::cast(klass)->external_name());
2385 return Klass::cast(klass)->is_public() &&
2386 (instanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2387 instanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2388 }
2389
2390 methodOop SystemDictionary::find_method_handle_invoke(Symbol* name,
2391 Symbol* signature,
2392 KlassHandle accessing_klass,
2393 TRAPS) {
2394 if (!EnableInvokeDynamic) return NULL;
2395 vmSymbols::SID name_id = vmSymbols::find_sid(name);
2396 assert(name_id != vmSymbols::NO_SID, "must be a known name");
2397 unsigned int hash = invoke_method_table()->compute_hash(signature, name_id);
2398 int index = invoke_method_table()->hash_to_index(hash);
2399 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, name_id);
2400 methodHandle non_cached_result;
2401 if (spe == NULL || spe->property_oop() == NULL) {
2402 spe = NULL;
2403 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2404 if (THREAD->is_Compiler_thread())
2405 return NULL; // do not attempt from within compiler
2406 bool for_invokeGeneric = (name_id != vmSymbols::VM_SYMBOL_ENUM_NAME(invokeExact_name));
2407 bool found_on_bcp = false;
2408 Handle mt = find_method_handle_type(signature, accessing_klass,
2409 for_invokeGeneric,
2410 found_on_bcp, CHECK_NULL);
2411 KlassHandle mh_klass = SystemDictionaryHandles::MethodHandle_klass();
2412 methodHandle m = methodOopDesc::make_invoke_method(mh_klass, name, signature,
2413 mt, CHECK_NULL);
2414 // Now grab the lock. We might have to throw away the new method,
2415 // if a racing thread has managed to install one at the same time.
2416 if (found_on_bcp) {
2417 MutexLocker ml(SystemDictionary_lock, Thread::current());
2418 spe = invoke_method_table()->find_entry(index, hash, signature, name_id);
2419 if (spe == NULL)
2420 spe = invoke_method_table()->add_entry(index, hash, signature, name_id);
2421 if (spe->property_oop() == NULL) {
2422 spe->set_property_oop(m());
2423 // Link m to his method type, if it is suitably generic.
2424 oop mtform = java_lang_invoke_MethodType::form(mt());
2425 if (mtform != NULL && mt() == java_lang_invoke_MethodTypeForm::erasedType(mtform)
2426 // vmlayout must be an invokeExact:
2427 && name_id == vmSymbols::VM_SYMBOL_ENUM_NAME(invokeExact_name)
2428 && java_lang_invoke_MethodTypeForm::vmlayout_offset_in_bytes() > 0) {
2429 java_lang_invoke_MethodTypeForm::init_vmlayout(mtform, m());
2430 }
2431 }
2432 } else {
2433 non_cached_result = m;
2434 }
2435 }
2436 if (spe != NULL && spe->property_oop() != NULL) {
2437 assert(spe->property_oop()->is_method(), "");
2438 return (methodOop) spe->property_oop();
2439 } else {
2440 return non_cached_result();
2441 }
2442 }
2443
2444 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2445 // signature, as interpreted relative to the given class loader.
2446 // Because of class loader constraints, all method handle usage must be
2447 // consistent with this loader.
2448 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2449 KlassHandle accessing_klass,
2450 bool for_invokeGeneric,
2451 bool& return_bcp_flag,
2452 TRAPS) {
2453 Handle class_loader, protection_domain;
2454 if (accessing_klass.not_null()) {
2455 class_loader = Handle(THREAD, instanceKlass::cast(accessing_klass())->class_loader());
2456 protection_domain = Handle(THREAD, instanceKlass::cast(accessing_klass())->protection_domain());
2457 }
2458 bool can_be_cached = true;
2459 Handle empty;
2460 int npts = ArgumentCount(signature).size();
2461 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2462 int arg = 0;
2463 Handle rt; // the return type from the signature
2464 ResourceMark rm(THREAD);
2465 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2466 oop mirror = NULL;
2467 if (can_be_cached) {
2468 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2469 mirror = ss.as_java_mirror(Handle(), Handle(),
2470 SignatureStream::ReturnNull, CHECK_(empty));
2471 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2472 // Fall back to accessing_klass context.
2473 can_be_cached = false;
2474 }
2475 }
2476 if (!can_be_cached) {
2477 // Resolve, throwing a real error if it doesn't work.
2478 mirror = ss.as_java_mirror(class_loader, protection_domain,
2479 SignatureStream::NCDFError, CHECK_(empty));
2480 }
2481 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2482 if (ss.at_return_type())
2483 rt = Handle(THREAD, mirror);
2484 else
2485 pts->obj_at_put(arg++, mirror);
2486 // Check accessibility.
2487 if (ss.is_object() && accessing_klass.not_null()) {
2488 klassOop sel_klass = java_lang_Class::as_klassOop(mirror);
2489 // Emulate constantPoolOopDesc::verify_constant_pool_resolve.
2490 if (Klass::cast(sel_klass)->oop_is_objArray())
2491 sel_klass = objArrayKlass::cast(sel_klass)->bottom_klass();
2492 if (Klass::cast(sel_klass)->oop_is_instance()) {
2493 KlassHandle sel_kh(THREAD, sel_klass);
2494 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2495 }
2496 }
2497 }
2498 assert(arg == npts, "");
2499
2500 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2501 JavaCallArguments args(Handle(THREAD, rt()));
2502 args.push_oop(pts());
2503 JavaValue result(T_OBJECT);
2504 JavaCalls::call_static(&result,
2505 SystemDictionary::MethodHandleNatives_klass(),
2506 vmSymbols::findMethodHandleType_name(),
2507 vmSymbols::findMethodHandleType_signature(),
2508 &args, CHECK_(empty));
2509 Handle method_type(THREAD, (oop) result.get_jobject());
2510
2511 if (for_invokeGeneric) {
2512 // call java.lang.invoke.MethodHandleNatives::notifyGenericMethodType(MethodType) -> void
2513 JavaCallArguments args(Handle(THREAD, method_type()));
2514 JavaValue no_result(T_VOID);
2515 JavaCalls::call_static(&no_result,
2516 SystemDictionary::MethodHandleNatives_klass(),
2517 vmSymbols::notifyGenericMethodType_name(),
2518 vmSymbols::notifyGenericMethodType_signature(),
2519 &args, THREAD);
2520 if (HAS_PENDING_EXCEPTION) {
2521 // If the notification fails, just kill it.
2522 CLEAR_PENDING_EXCEPTION;
2523 }
2524 }
2525
2526 // report back to the caller with the MethodType and the "on_bcp" flag
2527 return_bcp_flag = can_be_cached;
2528 return method_type;
2529 }
2530
2531 // Ask Java code to find or construct a method handle constant.
2532 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2533 int ref_kind, //e.g., JVM_REF_invokeVirtual
2534 KlassHandle callee,
2535 Symbol* name_sym,
2536 Symbol* signature,
2537 TRAPS) {
2538 Handle empty;
2539 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2540 Handle type;
2541 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2542 bool ignore_is_on_bcp = false;
2543 type = find_method_handle_type(signature, caller, false, ignore_is_on_bcp, CHECK_(empty));
2544 } else {
2545 ResourceMark rm(THREAD);
2546 SignatureStream ss(signature, false);
2547 if (!ss.is_done()) {
2548 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2549 SignatureStream::NCDFError, CHECK_(empty));
2550 type = Handle(THREAD, mirror);
2551 ss.next();
2552 if (!ss.is_done()) type = Handle(); // error!
2553 }
2554 }
2555 if (type.is_null()) {
2556 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2557 }
2558
2559 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2560 JavaCallArguments args;
2561 args.push_oop(caller->java_mirror()); // the referring class
2562 args.push_int(ref_kind);
2563 args.push_oop(callee->java_mirror()); // the target class
2564 args.push_oop(name());
2565 args.push_oop(type());
2566 JavaValue result(T_OBJECT);
2567 JavaCalls::call_static(&result,
2568 SystemDictionary::MethodHandleNatives_klass(),
2569 vmSymbols::linkMethodHandleConstant_name(),
2570 vmSymbols::linkMethodHandleConstant_signature(),
2571 &args, CHECK_(empty));
2572 return Handle(THREAD, (oop) result.get_jobject());
2573 }
2574
2575 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2576 // name and signature, as interpreted relative to the given class loader.
2577 Handle SystemDictionary::make_dynamic_call_site(Handle bootstrap_method,
2578 Symbol* name,
2579 methodHandle signature_invoker,
2580 Handle info,
2581 methodHandle caller_method,
2582 int caller_bci,
2583 TRAPS) {
2584 Handle empty;
2585 guarantee(bootstrap_method.not_null() &&
2586 java_lang_invoke_MethodHandle::is_instance(bootstrap_method()),
2587 "caller must supply a valid BSM");
2588
2589 Handle caller_mname = MethodHandles::new_MemberName(CHECK_(empty));
2590 MethodHandles::init_MemberName(caller_mname(), caller_method());
2591
2592 // call java.lang.invoke.MethodHandleNatives::makeDynamicCallSite(bootm, name, mtype, info, caller_mname, caller_pos)
2593 oop name_str_oop = StringTable::intern(name, CHECK_(empty)); // not a handle!
2594 JavaCallArguments args(Handle(THREAD, bootstrap_method()));
2595 args.push_oop(name_str_oop);
2596 args.push_oop(signature_invoker->method_handle_type());
2597 args.push_oop(info());
2598 args.push_oop(caller_mname());
2599 args.push_int(caller_bci);
2600 JavaValue result(T_OBJECT);
2601 JavaCalls::call_static(&result,
2602 SystemDictionary::MethodHandleNatives_klass(),
2603 vmSymbols::makeDynamicCallSite_name(),
2604 vmSymbols::makeDynamicCallSite_signature(),
2605 &args, CHECK_(empty));
2606 oop call_site_oop = (oop) result.get_jobject();
2607 assert(call_site_oop->is_oop()
2608 /*&& java_lang_invoke_CallSite::is_instance(call_site_oop)*/, "must be sane");
2609 if (TraceMethodHandles) {
2610 #ifndef PRODUCT
2611 tty->print_cr("Linked invokedynamic bci=%d site="INTPTR_FORMAT":", caller_bci, call_site_oop);
2612 call_site_oop->print();
2613 tty->cr();
2614 #endif //PRODUCT
2615 }
2616 return call_site_oop;
2617 }
2618
2619 Handle SystemDictionary::find_bootstrap_method(methodHandle caller_method, int caller_bci,
2620 int cache_index,
2621 Handle& argument_info_result,
2622 TRAPS) {
2623 Handle empty;
2624
2625 constantPoolHandle pool;
2626 {
2627 klassOop caller = caller_method->method_holder();
2628 if (!Klass::cast(caller)->oop_is_instance()) return empty;
2629 pool = constantPoolHandle(THREAD, instanceKlass::cast(caller)->constants());
2630 }
2631
2632 int constant_pool_index = pool->cache()->entry_at(cache_index)->constant_pool_index();
2633 constantTag tag = pool->tag_at(constant_pool_index);
2634
2635 if (tag.is_invoke_dynamic()) {
2636 // JVM_CONSTANT_InvokeDynamic is an ordered pair of [bootm, name&type], plus optional arguments
2637 // The bootm, being a JVM_CONSTANT_MethodHandle, has its own cache entry.
2638 int bsm_index = pool->invoke_dynamic_bootstrap_method_ref_index_at(constant_pool_index);
2639 if (bsm_index != 0) {
2640 int bsm_index_in_cache = pool->cache()->entry_at(cache_index)->bootstrap_method_index_in_cache();
2641 DEBUG_ONLY(int bsm_index_2 = pool->cache()->entry_at(bsm_index_in_cache)->constant_pool_index());
2642 assert(bsm_index == bsm_index_2, "BSM constant lifted to cache");
2643 if (TraceMethodHandles) {
2644 tty->print_cr("resolving bootstrap method for "PTR_FORMAT" at %d at cache[%d]CP[%d]...",
2645 (intptr_t) caller_method(), caller_bci, cache_index, constant_pool_index);
2646 }
2647 oop bsm_oop = pool->resolve_cached_constant_at(bsm_index_in_cache, CHECK_(empty));
2648 if (TraceMethodHandles) {
2649 tty->print_cr("bootstrap method for "PTR_FORMAT" at %d retrieved as "PTR_FORMAT":",
2650 (intptr_t) caller_method(), caller_bci, (intptr_t) bsm_oop);
2651 }
2652 assert(bsm_oop->is_oop(), "must be sane");
2653 // caller must verify that it is of type MethodHandle
2654 Handle bsm(THREAD, bsm_oop);
2655 bsm_oop = NULL; // safety
2656
2657 // Extract the optional static arguments.
2658 Handle argument_info; // either null, or one arg, or Object[]{arg...}
2659 int argc = pool->invoke_dynamic_argument_count_at(constant_pool_index);
2660 if (TraceInvokeDynamic) {
2661 tty->print_cr("find_bootstrap_method: [%d/%d] CONSTANT_InvokeDynamic: %d[%d]",
2662 constant_pool_index, cache_index, bsm_index, argc);
2663 }
2664 if (argc > 0) {
2665 objArrayHandle arg_array;
2666 if (argc > 1) {
2667 objArrayOop arg_array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(), argc, CHECK_(empty));
2668 arg_array = objArrayHandle(THREAD, arg_array_oop);
2669 argument_info = arg_array;
2670 }
2671 for (int arg_i = 0; arg_i < argc; arg_i++) {
2672 int arg_index = pool->invoke_dynamic_argument_index_at(constant_pool_index, arg_i);
2673 oop arg_oop = pool->resolve_possibly_cached_constant_at(arg_index, CHECK_(empty));
2674 if (arg_array.is_null()) {
2675 argument_info = Handle(THREAD, arg_oop);
2676 } else {
2677 arg_array->obj_at_put(arg_i, arg_oop);
2678 }
2679 }
2680 }
2681
2682 argument_info_result = argument_info; // return argument_info to caller
2683 return bsm;
2684 }
2685 } else {
2686 ShouldNotReachHere(); // verifier does not allow this
2687 }
2688
2689 return empty;
2690 }
2691
2692 // Since the identity hash code for symbols changes when the symbols are
2693 // moved from the regular perm gen (hash in the mark word) to the shared
2694 // spaces (hash is the address), the classes loaded into the dictionary
2695 // may be in the wrong buckets.
2696
2697 void SystemDictionary::reorder_dictionary() {
2698 dictionary()->reorder_dictionary();
2699 }
2700
2701
2702 void SystemDictionary::copy_buckets(char** top, char* end) {
2703 dictionary()->copy_buckets(top, end);
2704 }
2705
2706
2707 void SystemDictionary::copy_table(char** top, char* end) {
2708 dictionary()->copy_table(top, end);
2709 }
2710
2711
2712 void SystemDictionary::reverse() {
2713 dictionary()->reverse();
2714 }
2715
2716 int SystemDictionary::number_of_classes() {
2717 return dictionary()->number_of_entries();
2718 }
2719
2720
2721 // ----------------------------------------------------------------------------
2722 #ifndef PRODUCT
2723
2724 void SystemDictionary::print() {
2725 dictionary()->print();
2726
2727 // Placeholders
2728 GCMutexLocker mu(SystemDictionary_lock);
2729 placeholders()->print();
2730
2731 // loader constraints - print under SD_lock
2732 constraints()->print();
2733 }
2734
2735 #endif
2736
2737 void SystemDictionary::verify() {
2738 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2739 guarantee(constraints() != NULL,
2740 "Verify of loader constraints failed");
2741 guarantee(dictionary()->number_of_entries() >= 0 &&
2742 placeholders()->number_of_entries() >= 0,
2743 "Verify of system dictionary failed");
2744
2745 // Verify dictionary
2746 dictionary()->verify();
2747
2748 GCMutexLocker mu(SystemDictionary_lock);
2749 placeholders()->verify();
2750
2751 // Verify constraint table
2752 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2753 constraints()->verify(dictionary(), placeholders());
2754 }
2755
2756
2757 void SystemDictionary::verify_obj_klass_present(Handle obj,
2758 Symbol* class_name,
2759 Handle class_loader) {
2760 GCMutexLocker mu(SystemDictionary_lock);
2761 Symbol* name;
2762
2763 klassOop probe = find_class(class_name, class_loader);
2764 if (probe == NULL) {
2765 probe = SystemDictionary::find_shared_class(class_name);
2766 if (probe == NULL) {
2767 name = find_placeholder(class_name, class_loader);
2768 }
2769 }
2770 guarantee(probe != NULL || name != NULL,
2771 "Loaded klasses should be in SystemDictionary");
2772 }
2773
2774 #ifndef PRODUCT
2775
2776 // statistics code
2777 class ClassStatistics: AllStatic {
2778 private:
2779 static int nclasses; // number of classes
2780 static int nmethods; // number of methods
2781 static int nmethoddata; // number of methodData
2782 static int class_size; // size of class objects in words
2783 static int method_size; // size of method objects in words
2784 static int debug_size; // size of debug info in methods
2785 static int methoddata_size; // size of methodData objects in words
2786
2787 static void do_class(klassOop k) {
2788 nclasses++;
2789 class_size += k->size();
2790 if (k->klass_part()->oop_is_instance()) {
2791 instanceKlass* ik = (instanceKlass*)k->klass_part();
2792 class_size += ik->methods()->size();
2793 class_size += ik->constants()->size();
2794 class_size += ik->local_interfaces()->size();
2795 class_size += ik->transitive_interfaces()->size();
2796 // We do not have to count implementors, since we only store one!
2797 class_size += ik->all_fields_count() * FieldInfo::field_slots;
2798 }
2799 }
2800
2801 static void do_method(methodOop m) {
2802 nmethods++;
2803 method_size += m->size();
2804 // class loader uses same objArray for empty vectors, so don't count these
2805 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2806 if (m->has_stackmap_table()) {
2807 method_size += m->stackmap_data()->size();
2808 }
2809
2810 methodDataOop mdo = m->method_data();
2811 if (mdo != NULL) {
2812 nmethoddata++;
2813 methoddata_size += mdo->size();
2814 }
2815 }
2816
2817 public:
2818 static void print() {
2819 SystemDictionary::classes_do(do_class);
2820 SystemDictionary::methods_do(do_method);
2821 tty->print_cr("Class statistics:");
2822 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2823 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2824 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2825 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2826 }
2827 };
2828
2829
2830 int ClassStatistics::nclasses = 0;
2831 int ClassStatistics::nmethods = 0;
2832 int ClassStatistics::nmethoddata = 0;
2833 int ClassStatistics::class_size = 0;
2834 int ClassStatistics::method_size = 0;
2835 int ClassStatistics::debug_size = 0;
2836 int ClassStatistics::methoddata_size = 0;
2837
2838 void SystemDictionary::print_class_statistics() {
2839 ResourceMark rm;
2840 ClassStatistics::print();
2841 }
2842
2843
2844 class MethodStatistics: AllStatic {
2845 public:
2846 enum {
2847 max_parameter_size = 10
2848 };
2849 private:
2850
2851 static int _number_of_methods;
2852 static int _number_of_final_methods;
2853 static int _number_of_static_methods;
2854 static int _number_of_native_methods;
2855 static int _number_of_synchronized_methods;
2856 static int _number_of_profiled_methods;
2857 static int _number_of_bytecodes;
2858 static int _parameter_size_profile[max_parameter_size];
2859 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2860
2861 static void initialize() {
2862 _number_of_methods = 0;
2863 _number_of_final_methods = 0;
2864 _number_of_static_methods = 0;
2865 _number_of_native_methods = 0;
2866 _number_of_synchronized_methods = 0;
2867 _number_of_profiled_methods = 0;
2868 _number_of_bytecodes = 0;
2869 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2870 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2871 };
2872
2873 static void do_method(methodOop m) {
2874 _number_of_methods++;
2875 // collect flag info
2876 if (m->is_final() ) _number_of_final_methods++;
2877 if (m->is_static() ) _number_of_static_methods++;
2878 if (m->is_native() ) _number_of_native_methods++;
2879 if (m->is_synchronized()) _number_of_synchronized_methods++;
2880 if (m->method_data() != NULL) _number_of_profiled_methods++;
2881 // collect parameter size info (add one for receiver, if any)
2882 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2883 // collect bytecodes info
2884 {
2885 Thread *thread = Thread::current();
2886 HandleMark hm(thread);
2887 BytecodeStream s(methodHandle(thread, m));
2888 Bytecodes::Code c;
2889 while ((c = s.next()) >= 0) {
2890 _number_of_bytecodes++;
2891 _bytecodes_profile[c]++;
2892 }
2893 }
2894 }
2895
2896 public:
2897 static void print() {
2898 initialize();
2899 SystemDictionary::methods_do(do_method);
2900 // generate output
2901 tty->cr();
2902 tty->print_cr("Method statistics (static):");
2903 // flag distribution
2904 tty->cr();
2905 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2906 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2907 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2908 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2909 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2910 // parameter size profile
2911 tty->cr();
2912 { int tot = 0;
2913 int avg = 0;
2914 for (int i = 0; i < max_parameter_size; i++) {
2915 int n = _parameter_size_profile[i];
2916 tot += n;
2917 avg += n*i;
2918 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2919 }
2920 assert(tot == _number_of_methods, "should be the same");
2921 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2922 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2923 }
2924 // bytecodes profile
2925 tty->cr();
2926 { int tot = 0;
2927 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2928 if (Bytecodes::is_defined(i)) {
2929 Bytecodes::Code c = Bytecodes::cast(i);
2930 int n = _bytecodes_profile[c];
2931 tot += n;
2932 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2933 }
2934 }
2935 assert(tot == _number_of_bytecodes, "should be the same");
2936 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2937 }
2938 tty->cr();
2939 }
2940 };
2941
2942 int MethodStatistics::_number_of_methods;
2943 int MethodStatistics::_number_of_final_methods;
2944 int MethodStatistics::_number_of_static_methods;
2945 int MethodStatistics::_number_of_native_methods;
2946 int MethodStatistics::_number_of_synchronized_methods;
2947 int MethodStatistics::_number_of_profiled_methods;
2948 int MethodStatistics::_number_of_bytecodes;
2949 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2950 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2951
2952
2953 void SystemDictionary::print_method_statistics() {
2954 MethodStatistics::print();
2955 }
2956
2957 #endif // PRODUCT