Tue, 26 Mar 2013 09:06:16 -0400
8009595: The UseSplitVerifier option needs to be deprecated.
Summary: Put UseSplitVerifier option on the deprecated list.
Reviewed-by: dcubed, kmo, acorn
1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "interpreter/bytecodeStream.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/gcLocker.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/methodData.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "oops/typeArrayKlass.hpp"
47 #include "prims/jvmtiEnvBase.hpp"
48 #include "prims/methodHandles.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fieldType.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/signature.hpp"
56 #include "services/classLoadingService.hpp"
57 #include "services/threadService.hpp"
60 Dictionary* SystemDictionary::_dictionary = NULL;
61 PlaceholderTable* SystemDictionary::_placeholders = NULL;
62 Dictionary* SystemDictionary::_shared_dictionary = NULL;
63 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
64 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
65 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
68 int SystemDictionary::_number_of_modifications = 0;
69 int SystemDictionary::_sdgeneration = 0;
70 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
71 20201,40423,99991};
73 oop SystemDictionary::_system_loader_lock_obj = NULL;
75 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
76 = { NULL /*, NULL...*/ };
78 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
80 oop SystemDictionary::_java_system_loader = NULL;
82 bool SystemDictionary::_has_loadClassInternal = false;
83 bool SystemDictionary::_has_checkPackageAccess = false;
85 // lazily initialized klass variables
86 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
89 // ----------------------------------------------------------------------------
90 // Java-level SystemLoader
92 oop SystemDictionary::java_system_loader() {
93 return _java_system_loader;
94 }
96 void SystemDictionary::compute_java_system_loader(TRAPS) {
97 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
98 JavaValue result(T_OBJECT);
99 JavaCalls::call_static(&result,
100 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
101 vmSymbols::getSystemClassLoader_name(),
102 vmSymbols::void_classloader_signature(),
103 CHECK);
105 _java_system_loader = (oop)result.get_jobject();
106 }
109 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
110 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
111 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
112 }
114 // ----------------------------------------------------------------------------
115 // debugging
117 #ifdef ASSERT
119 // return true if class_name contains no '.' (internal format is '/')
120 bool SystemDictionary::is_internal_format(Symbol* class_name) {
121 if (class_name != NULL) {
122 ResourceMark rm;
123 char* name = class_name->as_C_string();
124 return strchr(name, '.') == NULL;
125 } else {
126 return true;
127 }
128 }
130 #endif
132 // ----------------------------------------------------------------------------
133 // Parallel class loading check
135 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
136 if (UnsyncloadClass || class_loader.is_null()) return true;
137 if (AlwaysLockClassLoader) return false;
138 return java_lang_ClassLoader::parallelCapable(class_loader());
139 }
140 // ----------------------------------------------------------------------------
141 // ParallelDefineClass flag does not apply to bootclass loader
142 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
143 if (class_loader.is_null()) return false;
144 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
145 return true;
146 }
147 return false;
148 }
149 // ----------------------------------------------------------------------------
150 // Resolving of classes
152 // Forwards to resolve_or_null
154 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
155 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
156 if (HAS_PENDING_EXCEPTION || klass == NULL) {
157 KlassHandle k_h(THREAD, klass);
158 // can return a null klass
159 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
160 }
161 return klass;
162 }
164 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
165 if (HAS_PENDING_EXCEPTION) {
166 // If we have a pending exception we forward it to the caller, unless throw_error is true,
167 // in which case we have to check whether the pending exception is a ClassNotFoundException,
168 // and if so convert it to a NoClassDefFoundError
169 // And chain the original ClassNotFoundException
170 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
171 ResourceMark rm(THREAD);
172 assert(klass_h() == NULL, "Should not have result with exception pending");
173 Handle e(THREAD, PENDING_EXCEPTION);
174 CLEAR_PENDING_EXCEPTION;
175 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
176 } else {
177 return NULL;
178 }
179 }
180 // Class not found, throw appropriate error or exception depending on value of throw_error
181 if (klass_h() == NULL) {
182 ResourceMark rm(THREAD);
183 if (throw_error) {
184 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
185 } else {
186 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
187 }
188 }
189 return (Klass*)klass_h();
190 }
193 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
194 bool throw_error, TRAPS)
195 {
196 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
197 }
200 // Forwards to resolve_instance_class_or_null
202 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
203 assert(!THREAD->is_Compiler_thread(),
204 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
205 class_name->as_C_string(),
206 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
207 if (FieldType::is_array(class_name)) {
208 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
209 } else if (FieldType::is_obj(class_name)) {
210 ResourceMark rm(THREAD);
211 // Ignore wrapping L and ;.
212 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
213 class_name->utf8_length() - 2, CHECK_NULL);
214 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
215 } else {
216 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
217 }
218 }
220 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
221 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
222 }
224 // Forwards to resolve_instance_class_or_null
226 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
227 Handle class_loader,
228 Handle protection_domain,
229 TRAPS) {
230 assert(FieldType::is_array(class_name), "must be array");
231 Klass* k = NULL;
232 FieldArrayInfo fd;
233 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
234 // of this call
235 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
236 if (t == T_OBJECT) {
237 // naked oop "k" is OK here -- we assign back into it
238 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
239 class_loader,
240 protection_domain,
241 CHECK_NULL);
242 if (k != NULL) {
243 k = k->array_klass(fd.dimension(), CHECK_NULL);
244 }
245 } else {
246 k = Universe::typeArrayKlassObj(t);
247 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
248 }
249 return k;
250 }
253 // Must be called for any super-class or super-interface resolution
254 // during class definition to allow class circularity checking
255 // super-interface callers:
256 // parse_interfaces - for defineClass & jvmtiRedefineClasses
257 // super-class callers:
258 // ClassFileParser - for defineClass & jvmtiRedefineClasses
259 // load_shared_class - while loading a class from shared archive
260 // resolve_instance_class_or_null:
261 // via: handle_parallel_super_load
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
289 Symbol* class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
294 // Double-check, if child class is already loaded, just return super-class,interface
295 // Don't add a placedholder if already loaded, i.e. already in system dictionary
296 // Make sure there's a placeholder for the *child* before resolving.
297 // Used as a claim that this thread is currently loading superclass/classloader
298 // Used here for ClassCircularity checks and also for heap verification
299 // (every InstanceKlass in the heap needs to be in the system dictionary
300 // or have a placeholder).
301 // Must check ClassCircularity before checking if super class is already loaded
302 //
303 // We might not already have a placeholder if this child_name was
304 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
305 // the name of the class might not be known until the stream is actually
306 // parsed.
307 // Bugs 4643874, 4715493
308 // compute_hash can have a safepoint
310 ClassLoaderData* loader_data = class_loader_data(class_loader);
311 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
312 int d_index = dictionary()->hash_to_index(d_hash);
313 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
314 int p_index = placeholders()->hash_to_index(p_hash);
315 // can't throw error holding a lock
316 bool child_already_loaded = false;
317 bool throw_circularity_error = false;
318 {
319 MutexLocker mu(SystemDictionary_lock, THREAD);
320 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
321 Klass* quicksuperk;
322 // to support // loading: if child done loading, just return superclass
323 // if class_name, & class_loader don't match:
324 // if initial define, SD update will give LinkageError
325 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
326 // so we don't throw an exception here.
327 // see: nsk redefclass014 & java.lang.instrument Instrument032
328 if ((childk != NULL ) && (is_superclass) &&
329 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
331 ((quicksuperk->name() == class_name) &&
332 (quicksuperk->class_loader() == class_loader()))) {
333 return quicksuperk;
334 } else {
335 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
336 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
337 throw_circularity_error = true;
338 }
339 }
340 if (!throw_circularity_error) {
341 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
342 }
343 }
344 if (throw_circularity_error) {
345 ResourceMark rm(THREAD);
346 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
347 }
349 // java.lang.Object should have been found above
350 assert(class_name != NULL, "null super class for resolving");
351 // Resolve the super class or interface, check results on return
352 Klass* superk = SystemDictionary::resolve_or_null(class_name,
353 class_loader,
354 protection_domain,
355 THREAD);
357 KlassHandle superk_h(THREAD, superk);
359 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
360 // It is no longer necessary to keep the placeholder table alive until update_dictionary
361 // or error. GC used to walk the placeholder table as strong roots.
362 // The instanceKlass is kept alive because the class loader is on the stack,
363 // which keeps the loader_data alive, as well as all instanceKlasses in
364 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
365 {
366 MutexLocker mu(SystemDictionary_lock, THREAD);
367 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
368 SystemDictionary_lock->notify_all();
369 }
370 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
371 // can null superk
372 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
373 }
375 return superk_h();
376 }
378 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
379 Handle class_loader,
380 Handle protection_domain,
381 TRAPS) {
382 if(!has_checkPackageAccess()) return;
384 // Now we have to call back to java to check if the initating class has access
385 JavaValue result(T_VOID);
386 if (TraceProtectionDomainVerification) {
387 // Print out trace information
388 tty->print_cr("Checking package access");
389 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
390 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
391 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
392 }
394 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
395 JavaCalls::call_special(&result,
396 class_loader,
397 system_loader,
398 vmSymbols::checkPackageAccess_name(),
399 vmSymbols::class_protectiondomain_signature(),
400 Handle(THREAD, klass->java_mirror()),
401 protection_domain,
402 THREAD);
404 if (TraceProtectionDomainVerification) {
405 if (HAS_PENDING_EXCEPTION) {
406 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
407 } else {
408 tty->print_cr(" -> granted");
409 }
410 tty->cr();
411 }
413 if (HAS_PENDING_EXCEPTION) return;
415 // If no exception has been thrown, we have validated the protection domain
416 // Insert the protection domain of the initiating class into the set.
417 {
418 // We recalculate the entry here -- we've called out to java since
419 // the last time it was calculated.
420 ClassLoaderData* loader_data = class_loader_data(class_loader);
422 Symbol* kn = klass->name();
423 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
424 int d_index = dictionary()->hash_to_index(d_hash);
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 {
428 // Note that we have an entry, and entries can be deleted only during GC,
429 // so we cannot allow GC to occur while we're holding this entry.
431 // We're using a No_Safepoint_Verifier to catch any place where we
432 // might potentially do a GC at all.
433 // Dictionary::do_unloading() asserts that classes in SD are only
434 // unloaded at a safepoint. Anonymous classes are not in SD.
435 No_Safepoint_Verifier nosafepoint;
436 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
437 protection_domain, THREAD);
438 }
439 }
440 }
442 // We only get here if this thread finds that another thread
443 // has already claimed the placeholder token for the current operation,
444 // but that other thread either never owned or gave up the
445 // object lock
446 // Waits on SystemDictionary_lock to indicate placeholder table updated
447 // On return, caller must recheck placeholder table state
448 //
449 // We only get here if
450 // 1) custom classLoader, i.e. not bootstrap classloader
451 // 2) UnsyncloadClass not set
452 // 3) custom classLoader has broken the class loader objectLock
453 // so another thread got here in parallel
454 //
455 // lockObject must be held.
456 // Complicated dance due to lock ordering:
457 // Must first release the classloader object lock to
458 // allow initial definer to complete the class definition
459 // and to avoid deadlock
460 // Reclaim classloader lock object with same original recursion count
461 // Must release SystemDictionary_lock after notify, since
462 // class loader lock must be claimed before SystemDictionary_lock
463 // to prevent deadlocks
464 //
465 // The notify allows applications that did an untimed wait() on
466 // the classloader object lock to not hang.
467 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
468 assert_lock_strong(SystemDictionary_lock);
470 bool calledholdinglock
471 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
472 assert(calledholdinglock,"must hold lock for notify");
473 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
474 ObjectSynchronizer::notifyall(lockObject, THREAD);
475 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
476 SystemDictionary_lock->wait();
477 SystemDictionary_lock->unlock();
478 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
479 SystemDictionary_lock->lock();
480 }
482 // If the class in is in the placeholder table, class loading is in progress
483 // For cases where the application changes threads to load classes, it
484 // is critical to ClassCircularity detection that we try loading
485 // the superclass on the same thread internally, so we do parallel
486 // super class loading here.
487 // This also is critical in cases where the original thread gets stalled
488 // even in non-circularity situations.
489 // Note: 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 Klass* if other thread has completed load
493 // and we are done,
494 // If return null Klass* 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) {
499 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
500 ClassLoaderData* loader_data = class_loader_data(class_loader);
501 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
502 int d_index = dictionary()->hash_to_index(d_hash);
503 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
504 int p_index = placeholders()->hash_to_index(p_hash);
506 // superk is not used, resolve_super called for circularity check only
507 // This code is reached in two situations. One if this thread
508 // is loading the same class twice (e.g. ClassCircularity, or
509 // java.lang.instrument).
510 // The second is if another thread started the resolve_super first
511 // and has not yet finished.
512 // In both cases the original caller will clean up the placeholder
513 // entry on error.
514 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
515 superclassname,
516 class_loader,
517 protection_domain,
518 true,
519 CHECK_(nh));
521 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
522 // Serial class loaders and bootstrap classloader do wait for superclass loads
523 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
524 MutexLocker mu(SystemDictionary_lock, THREAD);
525 // Check if classloading completed while we were loading superclass or waiting
526 Klass* check = find_class(d_index, d_hash, name, loader_data);
527 if (check != NULL) {
528 // Klass is already loaded, so just return it
529 return(instanceKlassHandle(THREAD, check));
530 } else {
531 return nh;
532 }
533 }
535 // must loop to both handle other placeholder updates
536 // and spurious notifications
537 bool super_load_in_progress = true;
538 PlaceholderEntry* placeholder;
539 while (super_load_in_progress) {
540 MutexLocker mu(SystemDictionary_lock, THREAD);
541 // Check if classloading completed while we were loading superclass or waiting
542 Klass* check = find_class(d_index, d_hash, name, loader_data);
543 if (check != NULL) {
544 // Klass is already loaded, so just return it
545 return(instanceKlassHandle(THREAD, check));
546 } else {
547 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
548 if (placeholder && placeholder->super_load_in_progress() ){
549 // Before UnsyncloadClass:
550 // We only get here if the application has released the
551 // classloader lock when another thread was in the middle of loading a
552 // superclass/superinterface for this class, and now
553 // this thread is also trying to load this class.
554 // To minimize surprises, the first thread that started to
555 // load a class should be the one to complete the loading
556 // with the classfile it initially expected.
557 // This logic has the current thread wait once it has done
558 // all the superclass/superinterface loading it can, until
559 // the original thread completes the class loading or fails
560 // If it completes we will use the resulting InstanceKlass
561 // which we will find below in the systemDictionary.
562 // We also get here for parallel bootstrap classloader
563 if (class_loader.is_null()) {
564 SystemDictionary_lock->wait();
565 } else {
566 double_lock_wait(lockObject, THREAD);
567 }
568 } else {
569 // If not in SD and not in PH, other thread's load must have failed
570 super_load_in_progress = false;
571 }
572 }
573 }
574 return (nh);
575 }
578 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
579 assert(name != NULL && !FieldType::is_array(name) &&
580 !FieldType::is_obj(name), "invalid class name");
582 // UseNewReflection
583 // Fix for 4474172; see evaluation for more details
584 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
585 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
587 // Do lookup to see if class already exist and the protection domain
588 // has the right access
589 // This call uses find which checks protection domain already matches
590 // All subsequent calls use find_class, and set has_loaded_class so that
591 // before we return a result we call out to java to check for valid protection domain
592 // to allow returning the Klass* and add it to the pd_set if it is valid
593 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
594 int d_index = dictionary()->hash_to_index(d_hash);
595 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
596 protection_domain, THREAD);
597 if (probe != NULL) return probe;
600 // Non-bootstrap class loaders will call out to class loader and
601 // define via jvm/jni_DefineClass which will acquire the
602 // class loader object lock to protect against multiple threads
603 // defining the class in parallel by accident.
604 // This lock must be acquired here so the waiter will find
605 // any successful result in the SystemDictionary and not attempt
606 // the define
607 // ParallelCapable Classloaders and the bootstrap classloader,
608 // or all classloaders with UnsyncloadClass do not acquire lock here
609 bool DoObjectLock = true;
610 if (is_parallelCapable(class_loader)) {
611 DoObjectLock = false;
612 }
614 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
615 int p_index = placeholders()->hash_to_index(p_hash);
617 // Class is not in SystemDictionary so we have to do loading.
618 // Make sure we are synchronized on the class loader before we proceed
619 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
620 check_loader_lock_contention(lockObject, THREAD);
621 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
623 // Check again (after locking) if class already exist in SystemDictionary
624 bool class_has_been_loaded = false;
625 bool super_load_in_progress = false;
626 bool havesupername = false;
627 instanceKlassHandle k;
628 PlaceholderEntry* placeholder;
629 Symbol* superclassname = NULL;
631 {
632 MutexLocker mu(SystemDictionary_lock, THREAD);
633 Klass* check = find_class(d_index, d_hash, name, loader_data);
634 if (check != NULL) {
635 // Klass is already loaded, so just return it
636 class_has_been_loaded = true;
637 k = instanceKlassHandle(THREAD, check);
638 } else {
639 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
640 if (placeholder && placeholder->super_load_in_progress()) {
641 super_load_in_progress = true;
642 if (placeholder->havesupername() == true) {
643 superclassname = placeholder->supername();
644 havesupername = true;
645 }
646 }
647 }
648 }
650 // If the class is in the placeholder table, class loading is in progress
651 if (super_load_in_progress && havesupername==true) {
652 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
653 class_loader, protection_domain, lockObject, THREAD);
654 if (HAS_PENDING_EXCEPTION) {
655 return NULL;
656 }
657 if (!k.is_null()) {
658 class_has_been_loaded = true;
659 }
660 }
662 bool throw_circularity_error = false;
663 if (!class_has_been_loaded) {
664 bool load_instance_added = false;
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
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, loader_data);
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()) {
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 Klass* check = find_class(d_index, d_hash, name, loader_data);
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, loader_data);
722 }
723 }
724 }
725 }
726 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
727 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
728 // LOAD_INSTANCE in parallel
730 if (!throw_circularity_error && !class_has_been_loaded) {
731 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
732 load_instance_added = true;
733 // For class loaders that do not acquire the classloader object lock,
734 // if they did not catch another thread holding LOAD_INSTANCE,
735 // need a check analogous to the acquire ObjectLocker/find_class
736 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
737 // one final check if the load has already completed
738 // class loaders holding the ObjectLock shouldn't find the class here
739 Klass* check = find_class(d_index, d_hash, name, loader_data);
740 if (check != NULL) {
741 // Klass is already loaded, so return it after checking/adding protection domain
742 k = instanceKlassHandle(THREAD, check);
743 class_has_been_loaded = true;
744 }
745 }
746 }
748 // must throw error outside of owning lock
749 if (throw_circularity_error) {
750 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
751 ResourceMark rm(THREAD);
752 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
753 }
755 if (!class_has_been_loaded) {
757 // Do actual loading
758 k = load_instance_class(name, class_loader, THREAD);
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 Klass* check = find_class(d_index, d_hash, name, loader_data);
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 }
782 // If everything was OK (no exceptions, no null return value), and
783 // class_loader is NOT the defining loader, do a little more bookkeeping.
784 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
785 k->class_loader() != class_loader()) {
787 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
789 // Need to check for a PENDING_EXCEPTION again; check_constraints
790 // can throw and doesn't use the CHECK macro.
791 if (!HAS_PENDING_EXCEPTION) {
792 { // Grabbing the Compile_lock prevents systemDictionary updates
793 // during compilations.
794 MutexLocker mu(Compile_lock, THREAD);
795 update_dictionary(d_index, d_hash, p_index, p_hash,
796 k, class_loader, THREAD);
797 }
798 if (JvmtiExport::should_post_class_load()) {
799 Thread *thread = THREAD;
800 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
801 JvmtiExport::post_class_load((JavaThread *) thread, k());
802 }
803 }
804 }
805 } // load_instance_class loop
807 if (HAS_PENDING_EXCEPTION) {
808 // An exception, such as OOM could have happened at various places inside
809 // load_instance_class. We might have partially initialized a shared class
810 // and need to clean it up.
811 if (class_loader.is_null()) {
812 // In some cases k may be null. Let's find the shared class again.
813 instanceKlassHandle ik(THREAD, find_shared_class(name));
814 if (ik.not_null()) {
815 if (ik->class_loader_data() == NULL) {
816 // We didn't go as far as Klass::restore_unshareable_info(),
817 // so nothing to clean up.
818 } else {
819 MutexLocker mu(SystemDictionary_lock, THREAD);
820 Klass* kk = find_class(name, ik->class_loader_data());
821 if (kk != NULL) {
822 // No clean up is needed if the shared class has been entered
823 // into system dictionary, as load_shared_class() won't be called
824 // again.
825 } else {
826 clean_up_shared_class(ik, class_loader, THREAD);
827 }
828 }
829 }
830 }
831 }
833 if (load_instance_added == true) {
834 // clean up placeholder entries for LOAD_INSTANCE success or error
835 // This brackets the SystemDictionary updates for both defining
836 // and initiating loaders
837 MutexLocker mu(SystemDictionary_lock, THREAD);
838 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
839 SystemDictionary_lock->notify_all();
840 }
841 }
843 if (HAS_PENDING_EXCEPTION || k.is_null()) {
844 return NULL;
845 }
847 #ifdef ASSERT
848 {
849 ClassLoaderData* loader_data = k->class_loader_data();
850 MutexLocker mu(SystemDictionary_lock, THREAD);
851 Klass* kk = find_class(name, loader_data);
852 assert(kk == k(), "should be present in dictionary");
853 }
854 #endif
856 // return if the protection domain in NULL
857 if (protection_domain() == NULL) return k();
859 // Check the protection domain has the right access
860 {
861 MutexLocker mu(SystemDictionary_lock, THREAD);
862 // Note that we have an entry, and entries can be deleted only during GC,
863 // so we cannot allow GC to occur while we're holding this entry.
864 // We're using a No_Safepoint_Verifier to catch any place where we
865 // might potentially do a GC at all.
866 // Dictionary::do_unloading() asserts that classes in SD are only
867 // unloaded at a safepoint. Anonymous classes are not in SD.
868 No_Safepoint_Verifier nosafepoint;
869 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
870 loader_data,
871 protection_domain)) {
872 return k();
873 }
874 }
876 // Verify protection domain. If it fails an exception is thrown
877 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
879 return k();
880 }
883 // This routine does not lock the system dictionary.
884 //
885 // Since readers don't hold a lock, we must make sure that system
886 // dictionary entries are only removed at a safepoint (when only one
887 // thread is running), and are added to in a safe way (all links must
888 // be updated in an MT-safe manner).
889 //
890 // Callers should be aware that an entry could be added just after
891 // _dictionary->bucket(index) is read here, so the caller will not see
892 // the new entry.
894 Klass* SystemDictionary::find(Symbol* class_name,
895 Handle class_loader,
896 Handle protection_domain,
897 TRAPS) {
899 // UseNewReflection
900 // The result of this call should be consistent with the result
901 // of the call to resolve_instance_class_or_null().
902 // See evaluation 6790209 and 4474172 for more details.
903 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
904 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
906 if (loader_data == NULL) {
907 // If the ClassLoaderData has not been setup,
908 // then the class loader has no entries in the dictionary.
909 return NULL;
910 }
912 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
913 int d_index = dictionary()->hash_to_index(d_hash);
915 {
916 // Note that we have an entry, and entries can be deleted only during GC,
917 // so we cannot allow GC to occur while we're holding this entry.
918 // We're using a No_Safepoint_Verifier to catch any place where we
919 // might potentially do a GC at all.
920 // Dictionary::do_unloading() asserts that classes in SD are only
921 // unloaded at a safepoint. Anonymous classes are not in SD.
922 No_Safepoint_Verifier nosafepoint;
923 return dictionary()->find(d_index, d_hash, class_name, loader_data,
924 protection_domain, THREAD);
925 }
926 }
929 // Look for a loaded instance or array klass by name. Do not do any loading.
930 // return NULL in case of error.
931 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
932 Handle class_loader,
933 Handle protection_domain,
934 TRAPS) {
935 Klass* k = NULL;
936 assert(class_name != NULL, "class name must be non NULL");
938 if (FieldType::is_array(class_name)) {
939 // The name refers to an array. Parse the name.
940 // dimension and object_key in FieldArrayInfo are assigned as a
941 // side-effect of this call
942 FieldArrayInfo fd;
943 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
944 if (t != T_OBJECT) {
945 k = Universe::typeArrayKlassObj(t);
946 } else {
947 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
948 }
949 if (k != NULL) {
950 k = k->array_klass_or_null(fd.dimension());
951 }
952 } else {
953 k = find(class_name, class_loader, protection_domain, THREAD);
954 }
955 return k;
956 }
958 // Note: this method is much like resolve_from_stream, but
959 // updates no supplemental data structures.
960 // TODO consolidate the two methods with a helper routine?
961 Klass* SystemDictionary::parse_stream(Symbol* class_name,
962 Handle class_loader,
963 Handle protection_domain,
964 ClassFileStream* st,
965 KlassHandle host_klass,
966 GrowableArray<Handle>* cp_patches,
967 TRAPS) {
968 TempNewSymbol parsed_name = NULL;
970 ClassLoaderData* loader_data;
971 if (host_klass.not_null()) {
972 // Create a new CLD for anonymous class, that uses the same class loader
973 // as the host_klass
974 assert(EnableInvokeDynamic, "");
975 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
976 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
977 loader_data->record_dependency(host_klass(), CHECK_NULL);
978 } else {
979 loader_data = ClassLoaderData::class_loader_data(class_loader());
980 }
982 // Parse the stream. Note that we do this even though this klass might
983 // already be present in the SystemDictionary, otherwise we would not
984 // throw potential ClassFormatErrors.
985 //
986 // Note: "name" is updated.
988 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
989 loader_data,
990 protection_domain,
991 host_klass,
992 cp_patches,
993 parsed_name,
994 true,
995 THREAD);
998 if (host_klass.not_null() && k.not_null()) {
999 assert(EnableInvokeDynamic, "");
1000 k->set_host_klass(host_klass());
1001 // If it's anonymous, initialize it now, since nobody else will.
1003 {
1004 MutexLocker mu_r(Compile_lock, THREAD);
1006 // Add to class hierarchy, initialize vtables, and do possible
1007 // deoptimizations.
1008 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1010 // But, do not add to system dictionary.
1011 }
1013 // Rewrite and patch constant pool here.
1014 k->link_class(CHECK_NULL);
1015 if (cp_patches != NULL) {
1016 k->constants()->patch_resolved_references(cp_patches);
1017 }
1018 k->eager_initialize(CHECK_NULL);
1020 // notify jvmti
1021 if (JvmtiExport::should_post_class_load()) {
1022 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1023 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1024 }
1025 }
1026 assert(host_klass.not_null() || cp_patches == NULL,
1027 "cp_patches only found with host_klass");
1029 return k();
1030 }
1032 // Add a klass to the system from a stream (called by jni_DefineClass and
1033 // JVM_DefineClass).
1034 // Note: class_name can be NULL. In that case we do not know the name of
1035 // the class until we have parsed the stream.
1037 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1038 Handle class_loader,
1039 Handle protection_domain,
1040 ClassFileStream* st,
1041 bool verify,
1042 TRAPS) {
1044 // Classloaders that support parallelism, e.g. bootstrap classloader,
1045 // or all classloaders with UnsyncloadClass do not acquire lock here
1046 bool DoObjectLock = true;
1047 if (is_parallelCapable(class_loader)) {
1048 DoObjectLock = false;
1049 }
1051 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1053 // Make sure we are synchronized on the class loader before we proceed
1054 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1055 check_loader_lock_contention(lockObject, THREAD);
1056 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1058 TempNewSymbol parsed_name = NULL;
1060 // Parse the stream. Note that we do this even though this klass might
1061 // already be present in the SystemDictionary, otherwise we would not
1062 // throw potential ClassFormatErrors.
1063 //
1064 // Note: "name" is updated.
1066 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1067 loader_data,
1068 protection_domain,
1069 parsed_name,
1070 verify,
1071 THREAD);
1073 const char* pkg = "java/";
1074 if (!HAS_PENDING_EXCEPTION &&
1075 !class_loader.is_null() &&
1076 parsed_name != NULL &&
1077 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1078 // It is illegal to define classes in the "java." package from
1079 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1080 ResourceMark rm(THREAD);
1081 char* name = parsed_name->as_C_string();
1082 char* index = strrchr(name, '/');
1083 *index = '\0'; // chop to just the package name
1084 while ((index = strchr(name, '/')) != NULL) {
1085 *index = '.'; // replace '/' with '.' in package name
1086 }
1087 const char* fmt = "Prohibited package name: %s";
1088 size_t len = strlen(fmt) + strlen(name);
1089 char* message = NEW_RESOURCE_ARRAY(char, len);
1090 jio_snprintf(message, len, fmt, name);
1091 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1092 vmSymbols::java_lang_SecurityException(), message);
1093 }
1095 if (!HAS_PENDING_EXCEPTION) {
1096 assert(parsed_name != NULL, "Sanity");
1097 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1098 // Verification prevents us from creating names with dots in them, this
1099 // asserts that that's the case.
1100 assert(is_internal_format(parsed_name),
1101 "external class name format used internally");
1103 // Add class just loaded
1104 // If a class loader supports parallel classloading handle parallel define requests
1105 // find_or_define_instance_class may return a different InstanceKlass
1106 if (is_parallelCapable(class_loader)) {
1107 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1108 } else {
1109 define_instance_class(k, THREAD);
1110 }
1111 }
1113 // Make sure we have an entry in the SystemDictionary on success
1114 debug_only( {
1115 if (!HAS_PENDING_EXCEPTION) {
1116 assert(parsed_name != NULL, "parsed_name is still null?");
1117 Symbol* h_name = k->name();
1118 ClassLoaderData *defining_loader_data = k->class_loader_data();
1120 MutexLocker mu(SystemDictionary_lock, THREAD);
1122 Klass* check = find_class(parsed_name, loader_data);
1123 assert(check == k(), "should be present in the dictionary");
1125 Klass* check2 = find_class(h_name, defining_loader_data);
1126 assert(check == check2, "name inconsistancy in SystemDictionary");
1127 }
1128 } );
1130 return k();
1131 }
1134 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1135 int number_of_entries) {
1136 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1137 "bad shared dictionary size.");
1138 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1139 }
1142 // If there is a shared dictionary, then find the entry for the
1143 // given shared system class, if any.
1145 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1146 if (shared_dictionary() != NULL) {
1147 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1148 int d_index = shared_dictionary()->hash_to_index(d_hash);
1150 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1151 } else {
1152 return NULL;
1153 }
1154 }
1157 // Load a class from the shared spaces (found through the shared system
1158 // dictionary). Force the superclass and all interfaces to be loaded.
1159 // Update the class definition to include sibling classes and no
1160 // subclasses (yet). [Classes in the shared space are not part of the
1161 // object hierarchy until loaded.]
1163 instanceKlassHandle SystemDictionary::load_shared_class(
1164 Symbol* class_name, Handle class_loader, TRAPS) {
1165 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1166 return load_shared_class(ik, class_loader, THREAD);
1167 }
1169 instanceKlassHandle SystemDictionary::load_shared_class(
1170 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1171 assert(class_loader.is_null(), "non-null classloader for shared class?");
1172 if (ik.not_null()) {
1173 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1174 Symbol* class_name = ik->name();
1176 // Found the class, now load the superclass and interfaces. If they
1177 // are shared, add them to the main system dictionary and reset
1178 // their hierarchy references (supers, subs, and interfaces).
1180 if (ik->super() != NULL) {
1181 Symbol* cn = ik->super()->name();
1182 resolve_super_or_fail(class_name, cn,
1183 class_loader, Handle(), true, CHECK_(nh));
1184 }
1186 Array<Klass*>* interfaces = ik->local_interfaces();
1187 int num_interfaces = interfaces->length();
1188 for (int index = 0; index < num_interfaces; index++) {
1189 Klass* k = interfaces->at(index);
1191 // Note: can not use InstanceKlass::cast here because
1192 // interfaces' InstanceKlass's C++ vtbls haven't been
1193 // reinitialized yet (they will be once the interface classes
1194 // are loaded)
1195 Symbol* name = k->name();
1196 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1197 }
1199 // Adjust methods to recover missing data. They need addresses for
1200 // interpreter entry points and their default native method address
1201 // must be reset.
1203 // Updating methods must be done under a lock so multiple
1204 // threads don't update these in parallel
1205 // Shared classes are all currently loaded by the bootstrap
1206 // classloader, so this will never cause a deadlock on
1207 // a custom class loader lock.
1209 {
1210 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1211 check_loader_lock_contention(lockObject, THREAD);
1212 ObjectLocker ol(lockObject, THREAD, true);
1213 ik->restore_unshareable_info(CHECK_(nh));
1214 }
1216 if (TraceClassLoading) {
1217 ResourceMark rm;
1218 tty->print("[Loaded %s", ik->external_name());
1219 tty->print(" from shared objects file");
1220 tty->print_cr("]");
1221 }
1222 // notify a class loaded from shared object
1223 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1224 true /* shared class */);
1225 }
1226 return ik;
1227 }
1229 void SystemDictionary::clean_up_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS) {
1230 // Updating methods must be done under a lock so multiple
1231 // threads don't update these in parallel
1232 // Shared classes are all currently loaded by the bootstrap
1233 // classloader, so this will never cause a deadlock on
1234 // a custom class loader lock.
1235 {
1236 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1237 check_loader_lock_contention(lockObject, THREAD);
1238 ObjectLocker ol(lockObject, THREAD, true);
1239 ik->remove_unshareable_info();
1240 }
1241 }
1243 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1244 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1245 if (class_loader.is_null()) {
1247 // Search the shared system dictionary for classes preloaded into the
1248 // shared spaces.
1249 instanceKlassHandle k;
1250 {
1251 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1252 k = load_shared_class(class_name, class_loader, THREAD);
1253 }
1255 if (k.is_null()) {
1256 // Use VM class loader
1257 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1258 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1259 }
1261 // find_or_define_instance_class may return a different InstanceKlass
1262 if (!k.is_null()) {
1263 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1264 }
1265 return k;
1266 } else {
1267 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1268 ResourceMark rm(THREAD);
1270 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1271 JavaThread* jt = (JavaThread*) THREAD;
1273 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1274 ClassLoader::perf_app_classload_selftime(),
1275 ClassLoader::perf_app_classload_count(),
1276 jt->get_thread_stat()->perf_recursion_counts_addr(),
1277 jt->get_thread_stat()->perf_timers_addr(),
1278 PerfClassTraceTime::CLASS_LOAD);
1280 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1281 // Translate to external class name format, i.e., convert '/' chars to '.'
1282 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1284 JavaValue result(T_OBJECT);
1286 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1288 // Call public unsynchronized loadClass(String) directly for all class loaders
1289 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1290 // acquire a class-name based lock rather than the class loader object lock.
1291 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1292 // so the call to loadClassInternal() was not required.
1293 //
1294 // UnsyncloadClass flag means both call loadClass(String) and do
1295 // not acquire the class loader lock even for class loaders that are
1296 // not parallelCapable. This was a risky transitional
1297 // flag for diagnostic purposes only. It is risky to call
1298 // custom class loaders without synchronization.
1299 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1300 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1301 // Do NOT assume this will be supported in future releases.
1302 //
1303 // Added MustCallLoadClassInternal in case we discover in the field
1304 // a customer that counts on this call
1305 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1306 JavaCalls::call_special(&result,
1307 class_loader,
1308 spec_klass,
1309 vmSymbols::loadClassInternal_name(),
1310 vmSymbols::string_class_signature(),
1311 string,
1312 CHECK_(nh));
1313 } else {
1314 JavaCalls::call_virtual(&result,
1315 class_loader,
1316 spec_klass,
1317 vmSymbols::loadClass_name(),
1318 vmSymbols::string_class_signature(),
1319 string,
1320 CHECK_(nh));
1321 }
1323 assert(result.get_type() == T_OBJECT, "just checking");
1324 oop obj = (oop) result.get_jobject();
1326 // Primitive classes return null since forName() can not be
1327 // used to obtain any of the Class objects representing primitives or void
1328 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1329 instanceKlassHandle k =
1330 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1331 // For user defined Java class loaders, check that the name returned is
1332 // the same as that requested. This check is done for the bootstrap
1333 // loader when parsing the class file.
1334 if (class_name == k->name()) {
1335 return k;
1336 }
1337 }
1338 // Class is not found or has the wrong name, return NULL
1339 return nh;
1340 }
1341 }
1343 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1345 ClassLoaderData* loader_data = k->class_loader_data();
1346 Handle class_loader_h(THREAD, loader_data->class_loader());
1348 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1350 // for bootstrap and other parallel classloaders don't acquire lock,
1351 // use placeholder token
1352 // If a parallelCapable class loader calls define_instance_class instead of
1353 // find_or_define_instance_class to get here, we have a timing
1354 // hole with systemDictionary updates and check_constraints
1355 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1356 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1357 compute_loader_lock_object(class_loader_h, THREAD)),
1358 "define called without lock");
1359 }
1361 // Check class-loading constraints. Throw exception if violation is detected.
1362 // Grabs and releases SystemDictionary_lock
1363 // The check_constraints/find_class call and update_dictionary sequence
1364 // must be "atomic" for a specific class/classloader pair so we never
1365 // define two different instanceKlasses for that class/classloader pair.
1366 // Existing classloaders will call define_instance_class with the
1367 // classloader lock held
1368 // Parallel classloaders will call find_or_define_instance_class
1369 // which will require a token to perform the define class
1370 Symbol* name_h = k->name();
1371 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1372 int d_index = dictionary()->hash_to_index(d_hash);
1373 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1375 // Register class just loaded with class loader (placed in Vector)
1376 // Note we do this before updating the dictionary, as this can
1377 // fail with an OutOfMemoryError (if it does, we will *not* put this
1378 // class in the dictionary and will not update the class hierarchy).
1379 // JVMTI FollowReferences needs to find the classes this way.
1380 if (k->class_loader() != NULL) {
1381 methodHandle m(THREAD, Universe::loader_addClass_method());
1382 JavaValue result(T_VOID);
1383 JavaCallArguments args(class_loader_h);
1384 args.push_oop(Handle(THREAD, k->java_mirror()));
1385 JavaCalls::call(&result, m, &args, CHECK);
1386 }
1388 // Add the new class. We need recompile lock during update of CHA.
1389 {
1390 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1391 int p_index = placeholders()->hash_to_index(p_hash);
1393 MutexLocker mu_r(Compile_lock, THREAD);
1395 // Add to class hierarchy, initialize vtables, and do possible
1396 // deoptimizations.
1397 add_to_hierarchy(k, CHECK); // No exception, but can block
1399 // Add to systemDictionary - so other classes can see it.
1400 // Grabs and releases SystemDictionary_lock
1401 update_dictionary(d_index, d_hash, p_index, p_hash,
1402 k, class_loader_h, THREAD);
1403 }
1404 k->eager_initialize(THREAD);
1406 // notify jvmti
1407 if (JvmtiExport::should_post_class_load()) {
1408 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1409 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1411 }
1412 }
1414 // Support parallel classloading
1415 // All parallel class loaders, including bootstrap classloader
1416 // lock a placeholder entry for this class/class_loader pair
1417 // to allow parallel defines of different classes for this class loader
1418 // With AllowParallelDefine flag==true, in case they do not synchronize around
1419 // FindLoadedClass/DefineClass, calls, we check for parallel
1420 // loading for them, wait if a defineClass is in progress
1421 // and return the initial requestor's results
1422 // This flag does not apply to the bootstrap classloader.
1423 // With AllowParallelDefine flag==false, call through to define_instance_class
1424 // which will throw LinkageError: duplicate class definition.
1425 // False is the requested default.
1426 // For better performance, the class loaders should synchronize
1427 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1428 // potentially waste time reading and parsing the bytestream.
1429 // Note: VM callers should ensure consistency of k/class_name,class_loader
1430 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1432 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1433 Symbol* name_h = k->name(); // passed in class_name may be null
1434 ClassLoaderData* loader_data = class_loader_data(class_loader);
1436 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1437 int d_index = dictionary()->hash_to_index(d_hash);
1439 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1440 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1441 int p_index = placeholders()->hash_to_index(p_hash);
1442 PlaceholderEntry* probe;
1444 {
1445 MutexLocker mu(SystemDictionary_lock, THREAD);
1446 // First check if class already defined
1447 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1448 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1449 if (check != NULL) {
1450 return(instanceKlassHandle(THREAD, check));
1451 }
1452 }
1454 // Acquire define token for this class/classloader
1455 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1456 // Wait if another thread defining in parallel
1457 // All threads wait - even those that will throw duplicate class: otherwise
1458 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1459 // if other thread has not finished updating dictionary
1460 while (probe->definer() != NULL) {
1461 SystemDictionary_lock->wait();
1462 }
1463 // Only special cases allow parallel defines and can use other thread's results
1464 // Other cases fall through, and may run into duplicate defines
1465 // caught by finding an entry in the SystemDictionary
1466 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1467 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1468 SystemDictionary_lock->notify_all();
1469 #ifdef ASSERT
1470 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1471 assert(check != NULL, "definer missed recording success");
1472 #endif
1473 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1474 } else {
1475 // This thread will define the class (even if earlier thread tried and had an error)
1476 probe->set_definer(THREAD);
1477 }
1478 }
1480 define_instance_class(k, THREAD);
1482 Handle linkage_exception = Handle(); // null handle
1484 // definer must notify any waiting threads
1485 {
1486 MutexLocker mu(SystemDictionary_lock, THREAD);
1487 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1488 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1489 if (probe != NULL) {
1490 if (HAS_PENDING_EXCEPTION) {
1491 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1492 CLEAR_PENDING_EXCEPTION;
1493 } else {
1494 probe->set_instance_klass(k());
1495 }
1496 probe->set_definer(NULL);
1497 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1498 SystemDictionary_lock->notify_all();
1499 }
1500 }
1502 // Can't throw exception while holding lock due to rank ordering
1503 if (linkage_exception() != NULL) {
1504 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1505 }
1507 return k;
1508 }
1509 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1510 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1511 if (class_loader.is_null()) {
1512 return Handle(THREAD, _system_loader_lock_obj);
1513 } else {
1514 return class_loader;
1515 }
1516 }
1518 // This method is added to check how often we have to wait to grab loader
1519 // lock. The results are being recorded in the performance counters defined in
1520 // ClassLoader::_sync_systemLoaderLockContentionRate and
1521 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1522 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1523 if (!UsePerfData) {
1524 return;
1525 }
1527 assert(!loader_lock.is_null(), "NULL lock object");
1529 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1530 == ObjectSynchronizer::owner_other) {
1531 // contention will likely happen, so increment the corresponding
1532 // contention counter.
1533 if (loader_lock() == _system_loader_lock_obj) {
1534 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1535 } else {
1536 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1537 }
1538 }
1539 }
1541 // ----------------------------------------------------------------------------
1542 // Lookup
1544 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1545 Symbol* class_name,
1546 ClassLoaderData* loader_data) {
1547 assert_locked_or_safepoint(SystemDictionary_lock);
1548 assert (index == dictionary()->index_for(class_name, loader_data),
1549 "incorrect index?");
1551 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1552 return k;
1553 }
1556 // Basic find on classes in the midst of being loaded
1557 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1558 ClassLoaderData* loader_data) {
1559 assert_locked_or_safepoint(SystemDictionary_lock);
1560 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1561 int p_index = placeholders()->hash_to_index(p_hash);
1562 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1563 }
1566 // Used for assertions and verification only
1567 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1568 #ifndef ASSERT
1569 guarantee(VerifyBeforeGC ||
1570 VerifyDuringGC ||
1571 VerifyBeforeExit ||
1572 VerifyAfterGC, "too expensive");
1573 #endif
1574 assert_locked_or_safepoint(SystemDictionary_lock);
1576 // First look in the loaded class array
1577 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1578 int d_index = dictionary()->hash_to_index(d_hash);
1579 return find_class(d_index, d_hash, class_name, loader_data);
1580 }
1583 // Get the next class in the diictionary.
1584 Klass* SystemDictionary::try_get_next_class() {
1585 return dictionary()->try_get_next_class();
1586 }
1589 // ----------------------------------------------------------------------------
1590 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1591 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1592 // before a new class is used.
1594 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1595 assert(k.not_null(), "just checking");
1596 assert_locked_or_safepoint(Compile_lock);
1598 // Link into hierachy. Make sure the vtables are initialized before linking into
1599 k->append_to_sibling_list(); // add to superklass/sibling list
1600 k->process_interfaces(THREAD); // handle all "implements" declarations
1601 k->set_init_state(InstanceKlass::loaded);
1602 // Now flush all code that depended on old class hierarchy.
1603 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1604 // Also, first reinitialize vtable because it may have gotten out of synch
1605 // while the new class wasn't connected to the class hierarchy.
1606 Universe::flush_dependents_on(k);
1607 }
1610 // ----------------------------------------------------------------------------
1611 // GC support
1613 // Following roots during mark-sweep is separated in two phases.
1614 //
1615 // The first phase follows preloaded classes and all other system
1616 // classes, since these will never get unloaded anyway.
1617 //
1618 // The second phase removes (unloads) unreachable classes from the
1619 // system dictionary and follows the remaining classes' contents.
1621 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1622 blk->do_oop(&_java_system_loader);
1623 blk->do_oop(&_system_loader_lock_obj);
1625 dictionary()->always_strong_oops_do(blk);
1627 // Visit extra methods
1628 invoke_method_table()->oops_do(blk);
1629 }
1631 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1632 // Follow all system classes and temporary placeholders in dictionary
1633 dictionary()->always_strong_classes_do(closure);
1635 // Placeholders. These represent classes we're actively loading.
1636 placeholders()->classes_do(closure);
1637 }
1639 // Calculate a "good" systemdictionary size based
1640 // on predicted or current loaded classes count
1641 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1642 int newsize = _old_default_sdsize;
1643 if ((classcount > 0) && !DumpSharedSpaces) {
1644 int desiredsize = classcount/_average_depth_goal;
1645 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1646 newsize = _primelist[++_sdgeneration]) {
1647 if (desiredsize <= newsize) {
1648 break;
1649 }
1650 }
1651 }
1652 return newsize;
1653 }
1654 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1655 // Note: anonymous classes are not in the SD.
1656 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1657 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1658 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1659 bool unloading_occurred = false;
1660 if (has_dead_loaders) {
1661 unloading_occurred = dictionary()->do_unloading();
1662 constraints()->purge_loader_constraints();
1663 resolution_errors()->purge_resolution_errors();
1664 }
1665 return unloading_occurred;
1666 }
1668 void SystemDictionary::oops_do(OopClosure* f) {
1669 f->do_oop(&_java_system_loader);
1670 f->do_oop(&_system_loader_lock_obj);
1672 // Adjust dictionary
1673 dictionary()->oops_do(f);
1675 // Visit extra methods
1676 invoke_method_table()->oops_do(f);
1677 }
1679 // Extended Class redefinition support.
1680 // If one of these classes is replaced, we need to replace it in these places.
1681 // KlassClosure::do_klass should take the address of a class but we can
1682 // change that later.
1683 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1684 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1685 f->do_klass(_well_known_klasses[k]);
1686 }
1688 {
1689 for (int i = 0; i < T_VOID+1; i++) {
1690 if (_box_klasses[i] != NULL) {
1691 assert(i >= T_BOOLEAN, "checking");
1692 f->do_klass(_box_klasses[i]);
1693 }
1694 }
1695 }
1697 FilteredFieldsMap::classes_do(f);
1698 }
1700 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1701 f->do_klass(_abstract_ownable_synchronizer_klass);
1702 }
1704 // Just the classes from defining class loaders
1705 // Don't iterate over placeholders
1706 void SystemDictionary::classes_do(void f(Klass*)) {
1707 dictionary()->classes_do(f);
1708 }
1710 // Added for initialize_itable_for_klass
1711 // Just the classes from defining class loaders
1712 // Don't iterate over placeholders
1713 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1714 dictionary()->classes_do(f, CHECK);
1715 }
1717 // All classes, and their class loaders
1718 // Don't iterate over placeholders
1719 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1720 dictionary()->classes_do(f);
1721 }
1723 // All classes, and their class loaders
1724 // (added for helpers that use HandleMarks and ResourceMarks)
1725 // Don't iterate over placeholders
1726 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) {
1727 dictionary()->classes_do(f, CHECK);
1728 }
1730 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1731 placeholders()->entries_do(f);
1732 }
1734 void SystemDictionary::methods_do(void f(Method*)) {
1735 dictionary()->methods_do(f);
1736 invoke_method_table()->methods_do(f);
1737 }
1739 // ----------------------------------------------------------------------------
1740 // Lazily load klasses
1742 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1743 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1745 // if multiple threads calling this function, only one thread will load
1746 // the class. The other threads will find the loaded version once the
1747 // class is loaded.
1748 Klass* aos = _abstract_ownable_synchronizer_klass;
1749 if (aos == NULL) {
1750 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1751 // Force a fence to prevent any read before the write completes
1752 OrderAccess::fence();
1753 _abstract_ownable_synchronizer_klass = k;
1754 }
1755 }
1757 // ----------------------------------------------------------------------------
1758 // Initialization
1760 void SystemDictionary::initialize(TRAPS) {
1761 // Allocate arrays
1762 assert(dictionary() == NULL,
1763 "SystemDictionary should only be initialized once");
1764 _sdgeneration = 0;
1765 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1766 _placeholders = new PlaceholderTable(_nof_buckets);
1767 _number_of_modifications = 0;
1768 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1769 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1770 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1772 // Allocate private object used as system class loader lock
1773 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1774 // Initialize basic classes
1775 initialize_preloaded_classes(CHECK);
1776 }
1778 // Compact table of directions on the initialization of klasses:
1779 static const short wk_init_info[] = {
1780 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1781 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1782 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1783 | (int)SystemDictionary::option ),
1784 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1785 #undef WK_KLASS_INIT_INFO
1786 0
1787 };
1789 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1790 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1791 int info = wk_init_info[id - FIRST_WKID];
1792 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1793 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1794 Klass** klassp = &_well_known_klasses[id];
1795 bool must_load = (init_opt < SystemDictionary::Opt);
1796 if ((*klassp) == NULL) {
1797 if (must_load) {
1798 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1799 } else {
1800 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1801 }
1802 }
1803 return ((*klassp) != NULL);
1804 }
1806 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1807 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1808 for (int id = (int)start_id; id < (int)limit_id; id++) {
1809 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1810 int info = wk_init_info[id - FIRST_WKID];
1811 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1812 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1814 initialize_wk_klass((WKID)id, opt, CHECK);
1815 }
1817 // move the starting value forward to the limit:
1818 start_id = limit_id;
1819 }
1821 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1822 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1823 // Preload commonly used klasses
1824 WKID scan = FIRST_WKID;
1825 // first do Object, then String, Class
1826 if (UseSharedSpaces) {
1827 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1828 // Initialize the constant pool for the Object_class
1829 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1830 ik->constants()->restore_unshareable_info(CHECK);
1831 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1832 } else {
1833 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1834 }
1836 // Calculate offsets for String and Class classes since they are loaded and
1837 // can be used after this point.
1838 java_lang_String::compute_offsets();
1839 java_lang_Class::compute_offsets();
1841 // Fixup mirrors for classes loaded before java.lang.Class.
1842 // These calls iterate over the objects currently in the perm gen
1843 // so calling them at this point is matters (not before when there
1844 // are fewer objects and not later after there are more objects
1845 // in the perm gen.
1846 Universe::initialize_basic_type_mirrors(CHECK);
1847 Universe::fixup_mirrors(CHECK);
1849 // do a bunch more:
1850 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1852 // Preload ref klasses and set reference types
1853 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1854 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1856 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1857 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1858 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1859 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1860 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1862 // JSR 292 classes
1863 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1864 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1865 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1866 if (EnableInvokeDynamic) {
1867 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1868 } else {
1869 // Skip the JSR 292 classes, if not enabled.
1870 scan = WKID(jsr292_group_end + 1);
1871 }
1873 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1875 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1876 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1877 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1878 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1879 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1880 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1881 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1882 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1883 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1884 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1886 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1887 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1888 _has_loadClassInternal = (method != NULL);
1889 }
1890 { // Compute whether we should use checkPackageAccess or NOT
1891 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1892 _has_checkPackageAccess = (method != NULL);
1893 }
1894 }
1896 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1897 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1898 BasicType SystemDictionary::box_klass_type(Klass* k) {
1899 assert(k != NULL, "");
1900 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1901 if (_box_klasses[i] == k)
1902 return (BasicType)i;
1903 }
1904 return T_OBJECT;
1905 }
1907 // Constraints on class loaders. The details of the algorithm can be
1908 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1909 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1910 // that the system dictionary needs to maintain a set of contraints that
1911 // must be satisfied by all classes in the dictionary.
1912 // if defining is true, then LinkageError if already in systemDictionary
1913 // if initiating loader, then ok if InstanceKlass matches existing entry
1915 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1916 instanceKlassHandle k,
1917 Handle class_loader, bool defining,
1918 TRAPS) {
1919 const char *linkage_error = NULL;
1920 {
1921 Symbol* name = k->name();
1922 ClassLoaderData *loader_data = class_loader_data(class_loader);
1924 MutexLocker mu(SystemDictionary_lock, THREAD);
1926 Klass* check = find_class(d_index, d_hash, name, loader_data);
1927 if (check != (Klass*)NULL) {
1928 // if different InstanceKlass - duplicate class definition,
1929 // else - ok, class loaded by a different thread in parallel,
1930 // we should only have found it if it was done loading and ok to use
1931 // system dictionary only holds instance classes, placeholders
1932 // also holds array classes
1934 assert(check->oop_is_instance(), "noninstance in systemdictionary");
1935 if ((defining == true) || (k() != check)) {
1936 linkage_error = "loader (instance of %s): attempted duplicate class "
1937 "definition for name: \"%s\"";
1938 } else {
1939 return;
1940 }
1941 }
1943 #ifdef ASSERT
1944 Symbol* ph_check = find_placeholder(name, loader_data);
1945 assert(ph_check == NULL || ph_check == name, "invalid symbol");
1946 #endif
1948 if (linkage_error == NULL) {
1949 if (constraints()->check_or_update(k, class_loader, name) == false) {
1950 linkage_error = "loader constraint violation: loader (instance of %s)"
1951 " previously initiated loading for a different type with name \"%s\"";
1952 }
1953 }
1954 }
1956 // Throw error now if needed (cannot throw while holding
1957 // SystemDictionary_lock because of rank ordering)
1959 if (linkage_error) {
1960 ResourceMark rm(THREAD);
1961 const char* class_loader_name = loader_name(class_loader());
1962 char* type_name = k->name()->as_C_string();
1963 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1964 strlen(type_name);
1965 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1966 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1967 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1968 }
1969 }
1972 // Update system dictionary - done after check_constraint and add_to_hierachy
1973 // have been called.
1974 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1975 int p_index, unsigned int p_hash,
1976 instanceKlassHandle k,
1977 Handle class_loader,
1978 TRAPS) {
1979 // Compile_lock prevents systemDictionary updates during compilations
1980 assert_locked_or_safepoint(Compile_lock);
1981 Symbol* name = k->name();
1982 ClassLoaderData *loader_data = class_loader_data(class_loader);
1984 {
1985 MutexLocker mu1(SystemDictionary_lock, THREAD);
1987 // See whether biased locking is enabled and if so set it for this
1988 // klass.
1989 // Note that this must be done past the last potential blocking
1990 // point / safepoint. We enable biased locking lazily using a
1991 // VM_Operation to iterate the SystemDictionary and installing the
1992 // biasable mark word into each InstanceKlass's prototype header.
1993 // To avoid race conditions where we accidentally miss enabling the
1994 // optimization for one class in the process of being added to the
1995 // dictionary, we must not safepoint after the test of
1996 // BiasedLocking::enabled().
1997 if (UseBiasedLocking && BiasedLocking::enabled()) {
1998 // Set biased locking bit for all loaded classes; it will be
1999 // cleared if revocation occurs too often for this type
2000 // NOTE that we must only do this when the class is initally
2001 // defined, not each time it is referenced from a new class loader
2002 if (k->class_loader() == class_loader()) {
2003 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2004 }
2005 }
2007 // Assign a classid if one has not already been assigned. The
2008 // counter does not need to be atomically incremented since this
2009 // is only done while holding the SystemDictionary_lock.
2010 // All loaded classes get a unique ID.
2011 TRACE_INIT_ID(k);
2013 // Make a new system dictionary entry.
2014 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2015 if (sd_check == NULL) {
2016 dictionary()->add_klass(name, loader_data, k);
2017 notice_modification();
2018 }
2019 #ifdef ASSERT
2020 sd_check = find_class(d_index, d_hash, name, loader_data);
2021 assert (sd_check != NULL, "should have entry in system dictionary");
2022 // Note: there may be a placeholder entry: for circularity testing
2023 // or for parallel defines
2024 #endif
2025 SystemDictionary_lock->notify_all();
2026 }
2027 }
2030 // Try to find a class name using the loader constraints. The
2031 // loader constraints might know about a class that isn't fully loaded
2032 // yet and these will be ignored.
2033 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2034 Symbol* class_name, Handle class_loader, TRAPS) {
2036 // First see if it has been loaded directly.
2037 // Force the protection domain to be null. (This removes protection checks.)
2038 Handle no_protection_domain;
2039 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2040 no_protection_domain, CHECK_NULL);
2041 if (klass != NULL)
2042 return klass;
2044 // Now look to see if it has been loaded elsewhere, and is subject to
2045 // a loader constraint that would require this loader to return the
2046 // klass that is already loaded.
2047 if (FieldType::is_array(class_name)) {
2048 // For array classes, their Klass*s are not kept in the
2049 // constraint table. The element Klass*s are.
2050 FieldArrayInfo fd;
2051 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2052 if (t != T_OBJECT) {
2053 klass = Universe::typeArrayKlassObj(t);
2054 } else {
2055 MutexLocker mu(SystemDictionary_lock, THREAD);
2056 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2057 }
2058 // If element class already loaded, allocate array klass
2059 if (klass != NULL) {
2060 klass = klass->array_klass_or_null(fd.dimension());
2061 }
2062 } else {
2063 MutexLocker mu(SystemDictionary_lock, THREAD);
2064 // Non-array classes are easy: simply check the constraint table.
2065 klass = constraints()->find_constrained_klass(class_name, class_loader);
2066 }
2068 return klass;
2069 }
2072 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2073 Handle class_loader1,
2074 Handle class_loader2,
2075 Thread* THREAD) {
2076 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2077 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2079 Symbol* constraint_name = NULL;
2080 if (!FieldType::is_array(class_name)) {
2081 constraint_name = class_name;
2082 } else {
2083 // For array classes, their Klass*s are not kept in the
2084 // constraint table. The element classes are.
2085 FieldArrayInfo fd;
2086 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2087 // primitive types always pass
2088 if (t != T_OBJECT) {
2089 return true;
2090 } else {
2091 constraint_name = fd.object_key();
2092 }
2093 }
2094 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2095 int d_index1 = dictionary()->hash_to_index(d_hash1);
2097 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2098 int d_index2 = dictionary()->hash_to_index(d_hash2);
2099 {
2100 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2102 // Better never do a GC while we're holding these oops
2103 No_Safepoint_Verifier nosafepoint;
2105 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2106 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2107 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2108 klass2, class_loader2);
2109 }
2110 }
2112 // Add entry to resolution error table to record the error when the first
2113 // attempt to resolve a reference to a class has failed.
2114 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2115 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2116 int index = resolution_errors()->hash_to_index(hash);
2117 {
2118 MutexLocker ml(SystemDictionary_lock, Thread::current());
2119 resolution_errors()->add_entry(index, hash, pool, which, error);
2120 }
2121 }
2123 // Delete a resolution error for RedefineClasses for a constant pool is going away
2124 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2125 resolution_errors()->delete_entry(pool);
2126 }
2128 // Lookup resolution error table. Returns error if found, otherwise NULL.
2129 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2130 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2131 int index = resolution_errors()->hash_to_index(hash);
2132 {
2133 MutexLocker ml(SystemDictionary_lock, Thread::current());
2134 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2135 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2136 }
2137 }
2140 // Signature constraints ensure that callers and callees agree about
2141 // the meaning of type names in their signatures. This routine is the
2142 // intake for constraints. It collects them from several places:
2143 //
2144 // * LinkResolver::resolve_method (if check_access is true) requires
2145 // that the resolving class (the caller) and the defining class of
2146 // the resolved method (the callee) agree on each type in the
2147 // method's signature.
2148 //
2149 // * LinkResolver::resolve_interface_method performs exactly the same
2150 // checks.
2151 //
2152 // * LinkResolver::resolve_field requires that the constant pool
2153 // attempting to link to a field agree with the field's defining
2154 // class about the type of the field signature.
2155 //
2156 // * klassVtable::initialize_vtable requires that, when a class
2157 // overrides a vtable entry allocated by a superclass, that the
2158 // overriding method (i.e., the callee) agree with the superclass
2159 // on each type in the method's signature.
2160 //
2161 // * klassItable::initialize_itable requires that, when a class fills
2162 // in its itables, for each non-abstract method installed in an
2163 // itable, the method (i.e., the callee) agree with the interface
2164 // on each type in the method's signature.
2165 //
2166 // All those methods have a boolean (check_access, checkconstraints)
2167 // which turns off the checks. This is used from specialized contexts
2168 // such as bootstrapping, dumping, and debugging.
2169 //
2170 // No direct constraint is placed between the class and its
2171 // supertypes. Constraints are only placed along linked relations
2172 // between callers and callees. When a method overrides or implements
2173 // an abstract method in a supertype (superclass or interface), the
2174 // constraints are placed as if the supertype were the caller to the
2175 // overriding method. (This works well, since callers to the
2176 // supertype have already established agreement between themselves and
2177 // the supertype.) As a result of all this, a class can disagree with
2178 // its supertype about the meaning of a type name, as long as that
2179 // class neither calls a relevant method of the supertype, nor is
2180 // called (perhaps via an override) from the supertype.
2181 //
2182 //
2183 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2184 //
2185 // Make sure all class components (including arrays) in the given
2186 // signature will be resolved to the same class in both loaders.
2187 // Returns the name of the type that failed a loader constraint check, or
2188 // NULL if no constraint failed. The returned C string needs cleaning up
2189 // with a ResourceMark in the caller. No exception except OOME is thrown.
2190 // Arrays are not added to the loader constraint table, their elements are.
2191 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2192 Handle loader1, Handle loader2,
2193 bool is_method, TRAPS) {
2194 // Nothing to do if loaders are the same.
2195 if (loader1() == loader2()) {
2196 return NULL;
2197 }
2199 ResourceMark rm(THREAD);
2200 SignatureStream sig_strm(signature, is_method);
2201 while (!sig_strm.is_done()) {
2202 if (sig_strm.is_object()) {
2203 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2204 Symbol* sig = s;
2205 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2206 return sig->as_C_string();
2207 }
2208 }
2209 sig_strm.next();
2210 }
2211 return NULL;
2212 }
2215 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2216 Symbol* signature,
2217 TRAPS) {
2218 methodHandle empty;
2219 assert(EnableInvokeDynamic, "");
2220 assert(MethodHandles::is_signature_polymorphic(iid) &&
2221 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2222 iid != vmIntrinsics::_invokeGeneric,
2223 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2225 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2226 int index = invoke_method_table()->hash_to_index(hash);
2227 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2228 methodHandle m;
2229 if (spe == NULL || spe->method() == NULL) {
2230 spe = NULL;
2231 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2232 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2233 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2234 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2236 // Now grab the lock. We might have to throw away the new method,
2237 // if a racing thread has managed to install one at the same time.
2238 {
2239 MutexLocker ml(SystemDictionary_lock, THREAD);
2240 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2241 if (spe == NULL)
2242 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2243 if (spe->method() == NULL)
2244 spe->set_method(m());
2245 }
2246 }
2248 assert(spe != NULL && spe->method() != NULL, "");
2249 return spe->method();
2250 }
2252 // Helper for unpacking the return value from linkMethod and linkCallSite.
2253 static methodHandle unpack_method_and_appendix(Handle mname,
2254 KlassHandle accessing_klass,
2255 objArrayHandle appendix_box,
2256 Handle* appendix_result,
2257 TRAPS) {
2258 methodHandle empty;
2259 if (mname.not_null()) {
2260 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2261 if (vmtarget != NULL && vmtarget->is_method()) {
2262 Method* m = (Method*)vmtarget;
2263 oop appendix = appendix_box->obj_at(0);
2264 if (TraceMethodHandles) {
2265 #ifndef PRODUCT
2266 tty->print("Linked method="INTPTR_FORMAT": ", m);
2267 m->print();
2268 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2269 tty->cr();
2270 #endif //PRODUCT
2271 }
2272 (*appendix_result) = Handle(THREAD, appendix);
2273 // the target is stored in the cpCache and if a reference to this
2274 // MethodName is dropped we need a way to make sure the
2275 // class_loader containing this method is kept alive.
2276 // FIXME: the appendix might also preserve this dependency.
2277 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2278 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2279 return methodHandle(THREAD, m);
2280 }
2281 }
2282 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2283 return empty;
2284 }
2286 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2287 Symbol* signature,
2288 KlassHandle accessing_klass,
2289 Handle *appendix_result,
2290 Handle *method_type_result,
2291 TRAPS) {
2292 methodHandle empty;
2293 assert(EnableInvokeDynamic, "");
2294 assert(!THREAD->is_Compiler_thread(), "");
2295 Handle method_type =
2296 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2297 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2298 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2299 }
2301 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2302 int ref_kind = JVM_REF_invokeVirtual;
2303 Handle name_str = StringTable::intern(name, CHECK_(empty));
2304 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2305 assert(appendix_box->obj_at(0) == NULL, "");
2307 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2308 JavaCallArguments args;
2309 args.push_oop(accessing_klass()->java_mirror());
2310 args.push_int(ref_kind);
2311 args.push_oop(mh_klass()->java_mirror());
2312 args.push_oop(name_str());
2313 args.push_oop(method_type());
2314 args.push_oop(appendix_box());
2315 JavaValue result(T_OBJECT);
2316 JavaCalls::call_static(&result,
2317 SystemDictionary::MethodHandleNatives_klass(),
2318 vmSymbols::linkMethod_name(),
2319 vmSymbols::linkMethod_signature(),
2320 &args, CHECK_(empty));
2321 Handle mname(THREAD, (oop) result.get_jobject());
2322 (*method_type_result) = method_type;
2323 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2324 }
2327 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2328 // signature, as interpreted relative to the given class loader.
2329 // Because of class loader constraints, all method handle usage must be
2330 // consistent with this loader.
2331 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2332 KlassHandle accessing_klass,
2333 TRAPS) {
2334 Handle empty;
2335 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2336 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2337 int index = invoke_method_table()->hash_to_index(hash);
2338 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2339 if (spe != NULL && spe->method_type() != NULL) {
2340 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2341 return Handle(THREAD, spe->method_type());
2342 } else if (THREAD->is_Compiler_thread()) {
2343 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2344 return Handle(); // do not attempt from within compiler, unless it was cached
2345 }
2347 Handle class_loader, protection_domain;
2348 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2349 int npts = ArgumentCount(signature).size();
2350 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2351 int arg = 0;
2352 Handle rt; // the return type from the signature
2353 ResourceMark rm(THREAD);
2354 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2355 oop mirror = NULL;
2356 if (is_on_bcp) {
2357 // Note: class_loader & protection_domain are both null at this point.
2358 mirror = ss.as_java_mirror(class_loader, protection_domain,
2359 SignatureStream::ReturnNull, CHECK_(empty));
2360 if (mirror == NULL) {
2361 // fall back from BCP to accessing_klass
2362 if (accessing_klass.not_null()) {
2363 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2364 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2365 }
2366 is_on_bcp = false;
2367 }
2368 }
2369 if (!is_on_bcp) {
2370 // Resolve, throwing a real error if it doesn't work.
2371 mirror = ss.as_java_mirror(class_loader, protection_domain,
2372 SignatureStream::NCDFError, CHECK_(empty));
2373 }
2374 if (ss.at_return_type())
2375 rt = Handle(THREAD, mirror);
2376 else
2377 pts->obj_at_put(arg++, mirror);
2379 // Check accessibility.
2380 if (ss.is_object() && accessing_klass.not_null()) {
2381 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2382 mirror = NULL; // safety
2383 // Emulate ConstantPool::verify_constant_pool_resolve.
2384 if (sel_klass->oop_is_objArray())
2385 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2386 if (sel_klass->oop_is_instance()) {
2387 KlassHandle sel_kh(THREAD, sel_klass);
2388 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2389 }
2390 }
2391 }
2392 assert(arg == npts, "");
2394 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2395 JavaCallArguments args(Handle(THREAD, rt()));
2396 args.push_oop(pts());
2397 JavaValue result(T_OBJECT);
2398 JavaCalls::call_static(&result,
2399 SystemDictionary::MethodHandleNatives_klass(),
2400 vmSymbols::findMethodHandleType_name(),
2401 vmSymbols::findMethodHandleType_signature(),
2402 &args, CHECK_(empty));
2403 Handle method_type(THREAD, (oop) result.get_jobject());
2405 if (is_on_bcp) {
2406 // We can cache this MethodType inside the JVM.
2407 MutexLocker ml(SystemDictionary_lock, THREAD);
2408 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2409 if (spe == NULL)
2410 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2411 if (spe->method_type() == NULL) {
2412 spe->set_method_type(method_type());
2413 }
2414 }
2416 // report back to the caller with the MethodType
2417 return method_type;
2418 }
2420 // Ask Java code to find or construct a method handle constant.
2421 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2422 int ref_kind, //e.g., JVM_REF_invokeVirtual
2423 KlassHandle callee,
2424 Symbol* name_sym,
2425 Symbol* signature,
2426 TRAPS) {
2427 Handle empty;
2428 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2429 Handle type;
2430 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2431 type = find_method_handle_type(signature, caller, CHECK_(empty));
2432 } else {
2433 ResourceMark rm(THREAD);
2434 SignatureStream ss(signature, false);
2435 if (!ss.is_done()) {
2436 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2437 SignatureStream::NCDFError, CHECK_(empty));
2438 type = Handle(THREAD, mirror);
2439 ss.next();
2440 if (!ss.is_done()) type = Handle(); // error!
2441 }
2442 }
2443 if (type.is_null()) {
2444 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2445 }
2447 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2448 JavaCallArguments args;
2449 args.push_oop(caller->java_mirror()); // the referring class
2450 args.push_int(ref_kind);
2451 args.push_oop(callee->java_mirror()); // the target class
2452 args.push_oop(name());
2453 args.push_oop(type());
2454 JavaValue result(T_OBJECT);
2455 JavaCalls::call_static(&result,
2456 SystemDictionary::MethodHandleNatives_klass(),
2457 vmSymbols::linkMethodHandleConstant_name(),
2458 vmSymbols::linkMethodHandleConstant_signature(),
2459 &args, CHECK_(empty));
2460 return Handle(THREAD, (oop) result.get_jobject());
2461 }
2463 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2464 // name and signature, as interpreted relative to the given class loader.
2465 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2466 Handle bootstrap_specifier,
2467 Symbol* name,
2468 Symbol* type,
2469 Handle *appendix_result,
2470 Handle *method_type_result,
2471 TRAPS) {
2472 methodHandle empty;
2473 Handle bsm, info;
2474 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2475 bsm = bootstrap_specifier;
2476 } else {
2477 assert(bootstrap_specifier->is_objArray(), "");
2478 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2479 int len = args->length();
2480 assert(len >= 1, "");
2481 bsm = Handle(THREAD, args->obj_at(0));
2482 if (len > 1) {
2483 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2484 for (int i = 1; i < len; i++)
2485 args1->obj_at_put(i-1, args->obj_at(i));
2486 info = Handle(THREAD, args1);
2487 }
2488 }
2489 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2490 "caller must supply a valid BSM");
2492 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2493 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2495 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2496 assert(appendix_box->obj_at(0) == NULL, "");
2498 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2499 JavaCallArguments args;
2500 args.push_oop(caller->java_mirror());
2501 args.push_oop(bsm());
2502 args.push_oop(method_name());
2503 args.push_oop(method_type());
2504 args.push_oop(info());
2505 args.push_oop(appendix_box);
2506 JavaValue result(T_OBJECT);
2507 JavaCalls::call_static(&result,
2508 SystemDictionary::MethodHandleNatives_klass(),
2509 vmSymbols::linkCallSite_name(),
2510 vmSymbols::linkCallSite_signature(),
2511 &args, CHECK_(empty));
2512 Handle mname(THREAD, (oop) result.get_jobject());
2513 (*method_type_result) = method_type;
2514 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2515 }
2517 // Since the identity hash code for symbols changes when the symbols are
2518 // moved from the regular perm gen (hash in the mark word) to the shared
2519 // spaces (hash is the address), the classes loaded into the dictionary
2520 // may be in the wrong buckets.
2522 void SystemDictionary::reorder_dictionary() {
2523 dictionary()->reorder_dictionary();
2524 }
2527 void SystemDictionary::copy_buckets(char** top, char* end) {
2528 dictionary()->copy_buckets(top, end);
2529 }
2532 void SystemDictionary::copy_table(char** top, char* end) {
2533 dictionary()->copy_table(top, end);
2534 }
2537 void SystemDictionary::reverse() {
2538 dictionary()->reverse();
2539 }
2541 int SystemDictionary::number_of_classes() {
2542 return dictionary()->number_of_entries();
2543 }
2546 // ----------------------------------------------------------------------------
2547 #ifndef PRODUCT
2549 void SystemDictionary::print() {
2550 dictionary()->print();
2552 // Placeholders
2553 GCMutexLocker mu(SystemDictionary_lock);
2554 placeholders()->print();
2556 // loader constraints - print under SD_lock
2557 constraints()->print();
2558 }
2560 #endif
2562 void SystemDictionary::verify() {
2563 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2564 guarantee(constraints() != NULL,
2565 "Verify of loader constraints failed");
2566 guarantee(dictionary()->number_of_entries() >= 0 &&
2567 placeholders()->number_of_entries() >= 0,
2568 "Verify of system dictionary failed");
2570 // Verify dictionary
2571 dictionary()->verify();
2573 GCMutexLocker mu(SystemDictionary_lock);
2574 placeholders()->verify();
2576 // Verify constraint table
2577 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2578 constraints()->verify(dictionary(), placeholders());
2579 }
2582 void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
2583 ClassLoaderData* loader_data) {
2584 GCMutexLocker mu(SystemDictionary_lock);
2585 Symbol* name;
2587 Klass* probe = find_class(class_name, loader_data);
2588 if (probe == NULL) {
2589 probe = SystemDictionary::find_shared_class(class_name);
2590 if (probe == NULL) {
2591 name = find_placeholder(class_name, loader_data);
2592 }
2593 }
2594 guarantee(probe != NULL || name != NULL,
2595 "Loaded klasses should be in SystemDictionary");
2596 }
2598 #ifndef PRODUCT
2600 // statistics code
2601 class ClassStatistics: AllStatic {
2602 private:
2603 static int nclasses; // number of classes
2604 static int nmethods; // number of methods
2605 static int nmethoddata; // number of methodData
2606 static int class_size; // size of class objects in words
2607 static int method_size; // size of method objects in words
2608 static int debug_size; // size of debug info in methods
2609 static int methoddata_size; // size of methodData objects in words
2611 static void do_class(Klass* k) {
2612 nclasses++;
2613 class_size += k->size();
2614 if (k->oop_is_instance()) {
2615 InstanceKlass* ik = (InstanceKlass*)k;
2616 class_size += ik->methods()->size();
2617 class_size += ik->constants()->size();
2618 class_size += ik->local_interfaces()->size();
2619 class_size += ik->transitive_interfaces()->size();
2620 // We do not have to count implementors, since we only store one!
2621 // SSS: How should these be accounted now that they have moved?
2622 // class_size += ik->fields()->length();
2623 }
2624 }
2626 static void do_method(Method* m) {
2627 nmethods++;
2628 method_size += m->size();
2629 // class loader uses same objArray for empty vectors, so don't count these
2630 if (m->has_stackmap_table()) {
2631 method_size += m->stackmap_data()->size();
2632 }
2634 MethodData* mdo = m->method_data();
2635 if (mdo != NULL) {
2636 nmethoddata++;
2637 methoddata_size += mdo->size();
2638 }
2639 }
2641 public:
2642 static void print() {
2643 SystemDictionary::classes_do(do_class);
2644 SystemDictionary::methods_do(do_method);
2645 tty->print_cr("Class statistics:");
2646 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2647 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2648 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2649 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2650 }
2651 };
2654 int ClassStatistics::nclasses = 0;
2655 int ClassStatistics::nmethods = 0;
2656 int ClassStatistics::nmethoddata = 0;
2657 int ClassStatistics::class_size = 0;
2658 int ClassStatistics::method_size = 0;
2659 int ClassStatistics::debug_size = 0;
2660 int ClassStatistics::methoddata_size = 0;
2662 void SystemDictionary::print_class_statistics() {
2663 ResourceMark rm;
2664 ClassStatistics::print();
2665 }
2668 class MethodStatistics: AllStatic {
2669 public:
2670 enum {
2671 max_parameter_size = 10
2672 };
2673 private:
2675 static int _number_of_methods;
2676 static int _number_of_final_methods;
2677 static int _number_of_static_methods;
2678 static int _number_of_native_methods;
2679 static int _number_of_synchronized_methods;
2680 static int _number_of_profiled_methods;
2681 static int _number_of_bytecodes;
2682 static int _parameter_size_profile[max_parameter_size];
2683 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2685 static void initialize() {
2686 _number_of_methods = 0;
2687 _number_of_final_methods = 0;
2688 _number_of_static_methods = 0;
2689 _number_of_native_methods = 0;
2690 _number_of_synchronized_methods = 0;
2691 _number_of_profiled_methods = 0;
2692 _number_of_bytecodes = 0;
2693 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2694 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2695 };
2697 static void do_method(Method* m) {
2698 _number_of_methods++;
2699 // collect flag info
2700 if (m->is_final() ) _number_of_final_methods++;
2701 if (m->is_static() ) _number_of_static_methods++;
2702 if (m->is_native() ) _number_of_native_methods++;
2703 if (m->is_synchronized()) _number_of_synchronized_methods++;
2704 if (m->method_data() != NULL) _number_of_profiled_methods++;
2705 // collect parameter size info (add one for receiver, if any)
2706 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2707 // collect bytecodes info
2708 {
2709 Thread *thread = Thread::current();
2710 HandleMark hm(thread);
2711 BytecodeStream s(methodHandle(thread, m));
2712 Bytecodes::Code c;
2713 while ((c = s.next()) >= 0) {
2714 _number_of_bytecodes++;
2715 _bytecodes_profile[c]++;
2716 }
2717 }
2718 }
2720 public:
2721 static void print() {
2722 initialize();
2723 SystemDictionary::methods_do(do_method);
2724 // generate output
2725 tty->cr();
2726 tty->print_cr("Method statistics (static):");
2727 // flag distribution
2728 tty->cr();
2729 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2730 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2731 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2732 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2733 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2734 // parameter size profile
2735 tty->cr();
2736 { int tot = 0;
2737 int avg = 0;
2738 for (int i = 0; i < max_parameter_size; i++) {
2739 int n = _parameter_size_profile[i];
2740 tot += n;
2741 avg += n*i;
2742 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2743 }
2744 assert(tot == _number_of_methods, "should be the same");
2745 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2746 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2747 }
2748 // bytecodes profile
2749 tty->cr();
2750 { int tot = 0;
2751 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2752 if (Bytecodes::is_defined(i)) {
2753 Bytecodes::Code c = Bytecodes::cast(i);
2754 int n = _bytecodes_profile[c];
2755 tot += n;
2756 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2757 }
2758 }
2759 assert(tot == _number_of_bytecodes, "should be the same");
2760 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2761 }
2762 tty->cr();
2763 }
2764 };
2766 int MethodStatistics::_number_of_methods;
2767 int MethodStatistics::_number_of_final_methods;
2768 int MethodStatistics::_number_of_static_methods;
2769 int MethodStatistics::_number_of_native_methods;
2770 int MethodStatistics::_number_of_synchronized_methods;
2771 int MethodStatistics::_number_of_profiled_methods;
2772 int MethodStatistics::_number_of_bytecodes;
2773 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2774 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2777 void SystemDictionary::print_method_statistics() {
2778 MethodStatistics::print();
2779 }
2781 #endif // PRODUCT