Sat, 02 Aug 2014 16:28:59 -0400
8051012: Regression in verifier for <init> method call from inside of a branch
Summary: Fix stackmap matching for branches.
Reviewed-by: coleenp, lfoltan, acorn
1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "interpreter/bytecodeStream.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/gcLocker.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/methodData.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "oops/typeArrayKlass.hpp"
47 #include "prims/jvmtiEnvBase.hpp"
48 #include "prims/methodHandles.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fieldType.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/signature.hpp"
56 #include "services/classLoadingService.hpp"
57 #include "services/threadService.hpp"
58 #include "utilities/macros.hpp"
59 #include "utilities/ticks.hpp"
61 #if INCLUDE_TRACE
62 #include "trace/tracing.hpp"
63 #endif
65 Dictionary* SystemDictionary::_dictionary = NULL;
66 PlaceholderTable* SystemDictionary::_placeholders = NULL;
67 Dictionary* SystemDictionary::_shared_dictionary = NULL;
68 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
69 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
70 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
73 int SystemDictionary::_number_of_modifications = 0;
74 int SystemDictionary::_sdgeneration = 0;
75 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
76 20201,40423,99991};
78 oop SystemDictionary::_system_loader_lock_obj = NULL;
80 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
81 = { NULL /*, NULL...*/ };
83 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
85 oop SystemDictionary::_java_system_loader = NULL;
87 bool SystemDictionary::_has_loadClassInternal = false;
88 bool SystemDictionary::_has_checkPackageAccess = false;
90 // lazily initialized klass variables
91 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
94 // ----------------------------------------------------------------------------
95 // Java-level SystemLoader
97 oop SystemDictionary::java_system_loader() {
98 return _java_system_loader;
99 }
101 void SystemDictionary::compute_java_system_loader(TRAPS) {
102 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
103 JavaValue result(T_OBJECT);
104 JavaCalls::call_static(&result,
105 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
106 vmSymbols::getSystemClassLoader_name(),
107 vmSymbols::void_classloader_signature(),
108 CHECK);
110 _java_system_loader = (oop)result.get_jobject();
111 }
114 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
115 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
116 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
117 }
119 // ----------------------------------------------------------------------------
120 // debugging
122 #ifdef ASSERT
124 // return true if class_name contains no '.' (internal format is '/')
125 bool SystemDictionary::is_internal_format(Symbol* class_name) {
126 if (class_name != NULL) {
127 ResourceMark rm;
128 char* name = class_name->as_C_string();
129 return strchr(name, '.') == NULL;
130 } else {
131 return true;
132 }
133 }
135 #endif
137 // ----------------------------------------------------------------------------
138 // Parallel class loading check
140 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
141 if (UnsyncloadClass || class_loader.is_null()) return true;
142 if (AlwaysLockClassLoader) return false;
143 return java_lang_ClassLoader::parallelCapable(class_loader());
144 }
145 // ----------------------------------------------------------------------------
146 // ParallelDefineClass flag does not apply to bootclass loader
147 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
148 if (class_loader.is_null()) return false;
149 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
150 return true;
151 }
152 return false;
153 }
155 /**
156 * Returns true if the passed class loader is the extension class loader.
157 */
158 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
159 if (class_loader.is_null()) {
160 return false;
161 }
162 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
163 }
165 // ----------------------------------------------------------------------------
166 // Resolving of classes
168 // Forwards to resolve_or_null
170 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
171 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
172 if (HAS_PENDING_EXCEPTION || klass == NULL) {
173 KlassHandle k_h(THREAD, klass);
174 // can return a null klass
175 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
176 }
177 return klass;
178 }
180 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
181 if (HAS_PENDING_EXCEPTION) {
182 // If we have a pending exception we forward it to the caller, unless throw_error is true,
183 // in which case we have to check whether the pending exception is a ClassNotFoundException,
184 // and if so convert it to a NoClassDefFoundError
185 // And chain the original ClassNotFoundException
186 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
187 ResourceMark rm(THREAD);
188 assert(klass_h() == NULL, "Should not have result with exception pending");
189 Handle e(THREAD, PENDING_EXCEPTION);
190 CLEAR_PENDING_EXCEPTION;
191 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
192 } else {
193 return NULL;
194 }
195 }
196 // Class not found, throw appropriate error or exception depending on value of throw_error
197 if (klass_h() == NULL) {
198 ResourceMark rm(THREAD);
199 if (throw_error) {
200 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
201 } else {
202 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
203 }
204 }
205 return (Klass*)klass_h();
206 }
209 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
210 bool throw_error, TRAPS)
211 {
212 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
213 }
216 // Forwards to resolve_instance_class_or_null
218 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
219 assert(!THREAD->is_Compiler_thread(),
220 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
221 class_name->as_C_string(),
222 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
223 if (FieldType::is_array(class_name)) {
224 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
225 } else if (FieldType::is_obj(class_name)) {
226 ResourceMark rm(THREAD);
227 // Ignore wrapping L and ;.
228 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
229 class_name->utf8_length() - 2, CHECK_NULL);
230 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
231 } else {
232 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
233 }
234 }
236 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
237 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
238 }
240 // Forwards to resolve_instance_class_or_null
242 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
243 Handle class_loader,
244 Handle protection_domain,
245 TRAPS) {
246 assert(FieldType::is_array(class_name), "must be array");
247 Klass* k = NULL;
248 FieldArrayInfo fd;
249 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
250 // of this call
251 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
252 if (t == T_OBJECT) {
253 // naked oop "k" is OK here -- we assign back into it
254 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
255 class_loader,
256 protection_domain,
257 CHECK_NULL);
258 if (k != NULL) {
259 k = k->array_klass(fd.dimension(), CHECK_NULL);
260 }
261 } else {
262 k = Universe::typeArrayKlassObj(t);
263 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
264 }
265 return k;
266 }
269 // Must be called for any super-class or super-interface resolution
270 // during class definition to allow class circularity checking
271 // super-interface callers:
272 // parse_interfaces - for defineClass & jvmtiRedefineClasses
273 // super-class callers:
274 // ClassFileParser - for defineClass & jvmtiRedefineClasses
275 // load_shared_class - while loading a class from shared archive
276 // resolve_instance_class_or_null:
277 // via: handle_parallel_super_load
278 // when resolving a class that has an existing placeholder with
279 // a saved superclass [i.e. a defineClass is currently in progress]
280 // if another thread is trying to resolve the class, it must do
281 // super-class checks on its own thread to catch class circularity
282 // This last call is critical in class circularity checking for cases
283 // where classloading is delegated to different threads and the
284 // classloader lock is released.
285 // Take the case: Base->Super->Base
286 // 1. If thread T1 tries to do a defineClass of class Base
287 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
288 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
289 // so it tries to load Super
290 // 3. If we load the class internally, or user classloader uses same thread
291 // loadClassFromxxx or defineClass via parseClassFile Super ...
292 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
293 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
294 // 3.4 calls resolve_super_or_fail Base
295 // 3.5 finds T1,Base -> throws class circularity
296 //OR 4. If T2 tries to resolve Super via defineClass Super ...
297 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
298 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
299 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
300 // 4.4 finds T2, Super -> throws class circularity
301 // Must be called, even if superclass is null, since this is
302 // where the placeholder entry is created which claims this
303 // thread is loading this class/classloader.
304 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
305 Symbol* class_name,
306 Handle class_loader,
307 Handle protection_domain,
308 bool is_superclass,
309 TRAPS) {
310 // Double-check, if child class is already loaded, just return super-class,interface
311 // Don't add a placedholder if already loaded, i.e. already in system dictionary
312 // Make sure there's a placeholder for the *child* before resolving.
313 // Used as a claim that this thread is currently loading superclass/classloader
314 // Used here for ClassCircularity checks and also for heap verification
315 // (every InstanceKlass in the heap needs to be in the system dictionary
316 // or have a placeholder).
317 // Must check ClassCircularity before checking if super class is already loaded
318 //
319 // We might not already have a placeholder if this child_name was
320 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
321 // the name of the class might not be known until the stream is actually
322 // parsed.
323 // Bugs 4643874, 4715493
324 // compute_hash can have a safepoint
326 ClassLoaderData* loader_data = class_loader_data(class_loader);
327 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
328 int d_index = dictionary()->hash_to_index(d_hash);
329 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
330 int p_index = placeholders()->hash_to_index(p_hash);
331 // can't throw error holding a lock
332 bool child_already_loaded = false;
333 bool throw_circularity_error = false;
334 {
335 MutexLocker mu(SystemDictionary_lock, THREAD);
336 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
337 Klass* quicksuperk;
338 // to support // loading: if child done loading, just return superclass
339 // if class_name, & class_loader don't match:
340 // if initial define, SD update will give LinkageError
341 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
342 // so we don't throw an exception here.
343 // see: nsk redefclass014 & java.lang.instrument Instrument032
344 if ((childk != NULL ) && (is_superclass) &&
345 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
347 ((quicksuperk->name() == class_name) &&
348 (quicksuperk->class_loader() == class_loader()))) {
349 return quicksuperk;
350 } else {
351 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
352 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
353 throw_circularity_error = true;
354 }
355 }
356 if (!throw_circularity_error) {
357 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
358 }
359 }
360 if (throw_circularity_error) {
361 ResourceMark rm(THREAD);
362 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
363 }
365 // java.lang.Object should have been found above
366 assert(class_name != NULL, "null super class for resolving");
367 // Resolve the super class or interface, check results on return
368 Klass* superk = SystemDictionary::resolve_or_null(class_name,
369 class_loader,
370 protection_domain,
371 THREAD);
373 KlassHandle superk_h(THREAD, superk);
375 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
376 // It is no longer necessary to keep the placeholder table alive until update_dictionary
377 // or error. GC used to walk the placeholder table as strong roots.
378 // The instanceKlass is kept alive because the class loader is on the stack,
379 // which keeps the loader_data alive, as well as all instanceKlasses in
380 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
381 {
382 MutexLocker mu(SystemDictionary_lock, THREAD);
383 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
384 SystemDictionary_lock->notify_all();
385 }
386 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
387 // can null superk
388 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
389 }
391 return superk_h();
392 }
394 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
395 Handle class_loader,
396 Handle protection_domain,
397 TRAPS) {
398 if(!has_checkPackageAccess()) return;
400 // Now we have to call back to java to check if the initating class has access
401 JavaValue result(T_VOID);
402 if (TraceProtectionDomainVerification) {
403 // Print out trace information
404 tty->print_cr("Checking package access");
405 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
406 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
407 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
408 }
410 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
411 JavaCalls::call_special(&result,
412 class_loader,
413 system_loader,
414 vmSymbols::checkPackageAccess_name(),
415 vmSymbols::class_protectiondomain_signature(),
416 Handle(THREAD, klass->java_mirror()),
417 protection_domain,
418 THREAD);
420 if (TraceProtectionDomainVerification) {
421 if (HAS_PENDING_EXCEPTION) {
422 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
423 } else {
424 tty->print_cr(" -> granted");
425 }
426 tty->cr();
427 }
429 if (HAS_PENDING_EXCEPTION) return;
431 // If no exception has been thrown, we have validated the protection domain
432 // Insert the protection domain of the initiating class into the set.
433 {
434 // We recalculate the entry here -- we've called out to java since
435 // the last time it was calculated.
436 ClassLoaderData* loader_data = class_loader_data(class_loader);
438 Symbol* kn = klass->name();
439 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
440 int d_index = dictionary()->hash_to_index(d_hash);
442 MutexLocker mu(SystemDictionary_lock, THREAD);
443 {
444 // Note that we have an entry, and entries can be deleted only during GC,
445 // so we cannot allow GC to occur while we're holding this entry.
447 // We're using a No_Safepoint_Verifier to catch any place where we
448 // might potentially do a GC at all.
449 // Dictionary::do_unloading() asserts that classes in SD are only
450 // unloaded at a safepoint. Anonymous classes are not in SD.
451 No_Safepoint_Verifier nosafepoint;
452 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
453 protection_domain, THREAD);
454 }
455 }
456 }
458 // We only get here if this thread finds that another thread
459 // has already claimed the placeholder token for the current operation,
460 // but that other thread either never owned or gave up the
461 // object lock
462 // Waits on SystemDictionary_lock to indicate placeholder table updated
463 // On return, caller must recheck placeholder table state
464 //
465 // We only get here if
466 // 1) custom classLoader, i.e. not bootstrap classloader
467 // 2) UnsyncloadClass not set
468 // 3) custom classLoader has broken the class loader objectLock
469 // so another thread got here in parallel
470 //
471 // lockObject must be held.
472 // Complicated dance due to lock ordering:
473 // Must first release the classloader object lock to
474 // allow initial definer to complete the class definition
475 // and to avoid deadlock
476 // Reclaim classloader lock object with same original recursion count
477 // Must release SystemDictionary_lock after notify, since
478 // class loader lock must be claimed before SystemDictionary_lock
479 // to prevent deadlocks
480 //
481 // The notify allows applications that did an untimed wait() on
482 // the classloader object lock to not hang.
483 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
484 assert_lock_strong(SystemDictionary_lock);
486 bool calledholdinglock
487 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
488 assert(calledholdinglock,"must hold lock for notify");
489 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
490 ObjectSynchronizer::notifyall(lockObject, THREAD);
491 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
492 SystemDictionary_lock->wait();
493 SystemDictionary_lock->unlock();
494 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
495 SystemDictionary_lock->lock();
496 }
498 // If the class in is in the placeholder table, class loading is in progress
499 // For cases where the application changes threads to load classes, it
500 // is critical to ClassCircularity detection that we try loading
501 // the superclass on the same thread internally, so we do parallel
502 // super class loading here.
503 // This also is critical in cases where the original thread gets stalled
504 // even in non-circularity situations.
505 // Note: must call resolve_super_or_fail even if null super -
506 // to force placeholder entry creation for this class for circularity detection
507 // Caller must check for pending exception
508 // Returns non-null Klass* if other thread has completed load
509 // and we are done,
510 // If return null Klass* and no pending exception, the caller must load the class
511 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
512 Symbol* name, Symbol* superclassname, Handle class_loader,
513 Handle protection_domain, Handle lockObject, TRAPS) {
515 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
516 ClassLoaderData* loader_data = class_loader_data(class_loader);
517 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
518 int d_index = dictionary()->hash_to_index(d_hash);
519 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
520 int p_index = placeholders()->hash_to_index(p_hash);
522 // superk is not used, resolve_super called for circularity check only
523 // This code is reached in two situations. One if this thread
524 // is loading the same class twice (e.g. ClassCircularity, or
525 // java.lang.instrument).
526 // The second is if another thread started the resolve_super first
527 // and has not yet finished.
528 // In both cases the original caller will clean up the placeholder
529 // entry on error.
530 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
531 superclassname,
532 class_loader,
533 protection_domain,
534 true,
535 CHECK_(nh));
537 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
538 // Serial class loaders and bootstrap classloader do wait for superclass loads
539 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
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 return nh;
548 }
549 }
551 // must loop to both handle other placeholder updates
552 // and spurious notifications
553 bool super_load_in_progress = true;
554 PlaceholderEntry* placeholder;
555 while (super_load_in_progress) {
556 MutexLocker mu(SystemDictionary_lock, THREAD);
557 // Check if classloading completed while we were loading superclass or waiting
558 Klass* check = find_class(d_index, d_hash, name, loader_data);
559 if (check != NULL) {
560 // Klass is already loaded, so just return it
561 return(instanceKlassHandle(THREAD, check));
562 } else {
563 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
564 if (placeholder && placeholder->super_load_in_progress() ){
565 // Before UnsyncloadClass:
566 // We only get here if the application has released the
567 // classloader lock when another thread was in the middle of loading a
568 // superclass/superinterface for this class, and now
569 // this thread is also trying to load this class.
570 // To minimize surprises, the first thread that started to
571 // load a class should be the one to complete the loading
572 // with the classfile it initially expected.
573 // This logic has the current thread wait once it has done
574 // all the superclass/superinterface loading it can, until
575 // the original thread completes the class loading or fails
576 // If it completes we will use the resulting InstanceKlass
577 // which we will find below in the systemDictionary.
578 // We also get here for parallel bootstrap classloader
579 if (class_loader.is_null()) {
580 SystemDictionary_lock->wait();
581 } else {
582 double_lock_wait(lockObject, THREAD);
583 }
584 } else {
585 // If not in SD and not in PH, other thread's load must have failed
586 super_load_in_progress = false;
587 }
588 }
589 }
590 return (nh);
591 }
594 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
595 Handle class_loader,
596 Handle protection_domain,
597 TRAPS) {
598 assert(name != NULL && !FieldType::is_array(name) &&
599 !FieldType::is_obj(name), "invalid class name");
601 Ticks class_load_start_time = Ticks::now();
603 // UseNewReflection
604 // Fix for 4474172; see evaluation for more details
605 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
606 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
608 // Do lookup to see if class already exist and the protection domain
609 // has the right access
610 // This call uses find which checks protection domain already matches
611 // All subsequent calls use find_class, and set has_loaded_class so that
612 // before we return a result we call out to java to check for valid protection domain
613 // to allow returning the Klass* and add it to the pd_set if it is valid
614 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
615 int d_index = dictionary()->hash_to_index(d_hash);
616 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
617 protection_domain, THREAD);
618 if (probe != NULL) return probe;
621 // Non-bootstrap class loaders will call out to class loader and
622 // define via jvm/jni_DefineClass which will acquire the
623 // class loader object lock to protect against multiple threads
624 // defining the class in parallel by accident.
625 // This lock must be acquired here so the waiter will find
626 // any successful result in the SystemDictionary and not attempt
627 // the define
628 // ParallelCapable Classloaders and the bootstrap classloader,
629 // or all classloaders with UnsyncloadClass do not acquire lock here
630 bool DoObjectLock = true;
631 if (is_parallelCapable(class_loader)) {
632 DoObjectLock = false;
633 }
635 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
636 int p_index = placeholders()->hash_to_index(p_hash);
638 // Class is not in SystemDictionary so we have to do loading.
639 // Make sure we are synchronized on the class loader before we proceed
640 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
641 check_loader_lock_contention(lockObject, THREAD);
642 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
644 // Check again (after locking) if class already exist in SystemDictionary
645 bool class_has_been_loaded = false;
646 bool super_load_in_progress = false;
647 bool havesupername = false;
648 instanceKlassHandle k;
649 PlaceholderEntry* placeholder;
650 Symbol* superclassname = NULL;
652 {
653 MutexLocker mu(SystemDictionary_lock, THREAD);
654 Klass* check = find_class(d_index, d_hash, name, loader_data);
655 if (check != NULL) {
656 // Klass is already loaded, so just return it
657 class_has_been_loaded = true;
658 k = instanceKlassHandle(THREAD, check);
659 } else {
660 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
661 if (placeholder && placeholder->super_load_in_progress()) {
662 super_load_in_progress = true;
663 if (placeholder->havesupername() == true) {
664 superclassname = placeholder->supername();
665 havesupername = true;
666 }
667 }
668 }
669 }
671 // If the class is in the placeholder table, class loading is in progress
672 if (super_load_in_progress && havesupername==true) {
673 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
674 class_loader, protection_domain, lockObject, THREAD);
675 if (HAS_PENDING_EXCEPTION) {
676 return NULL;
677 }
678 if (!k.is_null()) {
679 class_has_been_loaded = true;
680 }
681 }
683 bool throw_circularity_error = false;
684 if (!class_has_been_loaded) {
685 bool load_instance_added = false;
687 // add placeholder entry to record loading instance class
688 // Five cases:
689 // All cases need to prevent modifying bootclasssearchpath
690 // in parallel with a classload of same classname
691 // Redefineclasses uses existence of the placeholder for the duration
692 // of the class load to prevent concurrent redefinition of not completely
693 // defined classes.
694 // case 1. traditional classloaders that rely on the classloader object lock
695 // - no other need for LOAD_INSTANCE
696 // case 2. traditional classloaders that break the classloader object lock
697 // as a deadlock workaround. Detection of this case requires that
698 // this check is done while holding the classloader object lock,
699 // and that lock is still held when calling classloader's loadClass.
700 // For these classloaders, we ensure that the first requestor
701 // completes the load and other requestors wait for completion.
702 // case 3. UnsyncloadClass - don't use objectLocker
703 // With this flag, we allow parallel classloading of a
704 // class/classloader pair
705 // case4. Bootstrap classloader - don't own objectLocker
706 // This classloader supports parallelism at the classloader level,
707 // but only allows a single load of a class/classloader pair.
708 // No performance benefit and no deadlock issues.
709 // case 5. parallelCapable user level classloaders - without objectLocker
710 // Allow parallel classloading of a class/classloader pair
712 {
713 MutexLocker mu(SystemDictionary_lock, THREAD);
714 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
715 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
716 if (oldprobe) {
717 // only need check_seen_thread once, not on each loop
718 // 6341374 java/lang/Instrument with -Xcomp
719 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
720 throw_circularity_error = true;
721 } else {
722 // case 1: traditional: should never see load_in_progress.
723 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
725 // case 4: bootstrap classloader: prevent futile classloading,
726 // wait on first requestor
727 if (class_loader.is_null()) {
728 SystemDictionary_lock->wait();
729 } else {
730 // case 2: traditional with broken classloader lock. wait on first
731 // requestor.
732 double_lock_wait(lockObject, THREAD);
733 }
734 // Check if classloading completed while we were waiting
735 Klass* check = find_class(d_index, d_hash, name, loader_data);
736 if (check != NULL) {
737 // Klass is already loaded, so just return it
738 k = instanceKlassHandle(THREAD, check);
739 class_has_been_loaded = true;
740 }
741 // check if other thread failed to load and cleaned up
742 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
743 }
744 }
745 }
746 }
747 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
748 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
749 // LOAD_INSTANCE in parallel
751 if (!throw_circularity_error && !class_has_been_loaded) {
752 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
753 load_instance_added = true;
754 // For class loaders that do not acquire the classloader object lock,
755 // if they did not catch another thread holding LOAD_INSTANCE,
756 // need a check analogous to the acquire ObjectLocker/find_class
757 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
758 // one final check if the load has already completed
759 // class loaders holding the ObjectLock shouldn't find the class here
760 Klass* check = find_class(d_index, d_hash, name, loader_data);
761 if (check != NULL) {
762 // Klass is already loaded, so return it after checking/adding protection domain
763 k = instanceKlassHandle(THREAD, check);
764 class_has_been_loaded = true;
765 }
766 }
767 }
769 // must throw error outside of owning lock
770 if (throw_circularity_error) {
771 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
772 ResourceMark rm(THREAD);
773 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
774 }
776 if (!class_has_been_loaded) {
778 // Do actual loading
779 k = load_instance_class(name, class_loader, THREAD);
781 // For UnsyncloadClass only
782 // If they got a linkageError, check if a parallel class load succeeded.
783 // If it did, then for bytecode resolution the specification requires
784 // that we return the same result we did for the other thread, i.e. the
785 // successfully loaded InstanceKlass
786 // Should not get here for classloaders that support parallelism
787 // with the new cleaner mechanism, even with AllowParallelDefineClass
788 // Bootstrap goes through here to allow for an extra guarantee check
789 if (UnsyncloadClass || (class_loader.is_null())) {
790 if (k.is_null() && HAS_PENDING_EXCEPTION
791 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
792 MutexLocker mu(SystemDictionary_lock, THREAD);
793 Klass* check = find_class(d_index, d_hash, name, loader_data);
794 if (check != NULL) {
795 // Klass is already loaded, so just use it
796 k = instanceKlassHandle(THREAD, check);
797 CLEAR_PENDING_EXCEPTION;
798 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
799 }
800 }
801 }
803 // If everything was OK (no exceptions, no null return value), and
804 // class_loader is NOT the defining loader, do a little more bookkeeping.
805 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
806 k->class_loader() != class_loader()) {
808 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
810 // Need to check for a PENDING_EXCEPTION again; check_constraints
811 // can throw and doesn't use the CHECK macro.
812 if (!HAS_PENDING_EXCEPTION) {
813 { // Grabbing the Compile_lock prevents systemDictionary updates
814 // during compilations.
815 MutexLocker mu(Compile_lock, THREAD);
816 update_dictionary(d_index, d_hash, p_index, p_hash,
817 k, class_loader, THREAD);
818 }
820 if (JvmtiExport::should_post_class_load()) {
821 Thread *thread = THREAD;
822 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
823 JvmtiExport::post_class_load((JavaThread *) thread, k());
824 }
825 }
826 }
827 } // load_instance_class loop
829 if (load_instance_added == true) {
830 // clean up placeholder entries for LOAD_INSTANCE success or error
831 // This brackets the SystemDictionary updates for both defining
832 // and initiating loaders
833 MutexLocker mu(SystemDictionary_lock, THREAD);
834 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
835 SystemDictionary_lock->notify_all();
836 }
837 }
839 if (HAS_PENDING_EXCEPTION || k.is_null()) {
840 return NULL;
841 }
843 post_class_load_event(class_load_start_time, k, class_loader);
845 #ifdef ASSERT
846 {
847 ClassLoaderData* loader_data = k->class_loader_data();
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 Klass* kk = find_class(name, loader_data);
850 assert(kk == k(), "should be present in dictionary");
851 }
852 #endif
854 // return if the protection domain in NULL
855 if (protection_domain() == NULL) return k();
857 // Check the protection domain has the right access
858 {
859 MutexLocker mu(SystemDictionary_lock, THREAD);
860 // Note that we have an entry, and entries can be deleted only during GC,
861 // so we cannot allow GC to occur while we're holding this entry.
862 // We're using a No_Safepoint_Verifier to catch any place where we
863 // might potentially do a GC at all.
864 // Dictionary::do_unloading() asserts that classes in SD are only
865 // unloaded at a safepoint. Anonymous classes are not in SD.
866 No_Safepoint_Verifier nosafepoint;
867 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
868 loader_data,
869 protection_domain)) {
870 return k();
871 }
872 }
874 // Verify protection domain. If it fails an exception is thrown
875 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
877 return k();
878 }
881 // This routine does not lock the system dictionary.
882 //
883 // Since readers don't hold a lock, we must make sure that system
884 // dictionary entries are only removed at a safepoint (when only one
885 // thread is running), and are added to in a safe way (all links must
886 // be updated in an MT-safe manner).
887 //
888 // Callers should be aware that an entry could be added just after
889 // _dictionary->bucket(index) is read here, so the caller will not see
890 // the new entry.
892 Klass* SystemDictionary::find(Symbol* class_name,
893 Handle class_loader,
894 Handle protection_domain,
895 TRAPS) {
897 // UseNewReflection
898 // The result of this call should be consistent with the result
899 // of the call to resolve_instance_class_or_null().
900 // See evaluation 6790209 and 4474172 for more details.
901 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
902 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
904 if (loader_data == NULL) {
905 // If the ClassLoaderData has not been setup,
906 // then the class loader has no entries in the dictionary.
907 return NULL;
908 }
910 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
911 int d_index = dictionary()->hash_to_index(d_hash);
913 {
914 // Note that we have an entry, and entries can be deleted only during GC,
915 // so we cannot allow GC to occur while we're holding this entry.
916 // We're using a No_Safepoint_Verifier to catch any place where we
917 // might potentially do a GC at all.
918 // Dictionary::do_unloading() asserts that classes in SD are only
919 // unloaded at a safepoint. Anonymous classes are not in SD.
920 No_Safepoint_Verifier nosafepoint;
921 return dictionary()->find(d_index, d_hash, class_name, loader_data,
922 protection_domain, THREAD);
923 }
924 }
927 // Look for a loaded instance or array klass by name. Do not do any loading.
928 // return NULL in case of error.
929 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
930 Handle class_loader,
931 Handle protection_domain,
932 TRAPS) {
933 Klass* k = NULL;
934 assert(class_name != NULL, "class name must be non NULL");
936 if (FieldType::is_array(class_name)) {
937 // The name refers to an array. Parse the name.
938 // dimension and object_key in FieldArrayInfo are assigned as a
939 // side-effect of this call
940 FieldArrayInfo fd;
941 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
942 if (t != T_OBJECT) {
943 k = Universe::typeArrayKlassObj(t);
944 } else {
945 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
946 }
947 if (k != NULL) {
948 k = k->array_klass_or_null(fd.dimension());
949 }
950 } else {
951 k = find(class_name, class_loader, protection_domain, THREAD);
952 }
953 return k;
954 }
956 // Note: this method is much like resolve_from_stream, but
957 // updates no supplemental data structures.
958 // TODO consolidate the two methods with a helper routine?
959 Klass* SystemDictionary::parse_stream(Symbol* class_name,
960 Handle class_loader,
961 Handle protection_domain,
962 ClassFileStream* st,
963 KlassHandle host_klass,
964 GrowableArray<Handle>* cp_patches,
965 TRAPS) {
966 TempNewSymbol parsed_name = NULL;
968 Ticks class_load_start_time = Ticks::now();
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 // If it's anonymous, initialize it now, since nobody else will.
1002 {
1003 MutexLocker mu_r(Compile_lock, THREAD);
1005 // Add to class hierarchy, initialize vtables, and do possible
1006 // deoptimizations.
1007 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1009 // But, do not add to system dictionary.
1011 // compiled code dependencies need to be validated anyway
1012 notice_modification();
1013 }
1015 // Rewrite and patch constant pool here.
1016 k->link_class(CHECK_NULL);
1017 if (cp_patches != NULL) {
1018 k->constants()->patch_resolved_references(cp_patches);
1019 }
1020 k->eager_initialize(CHECK_NULL);
1022 // notify jvmti
1023 if (JvmtiExport::should_post_class_load()) {
1024 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1025 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1026 }
1028 post_class_load_event(class_load_start_time, k, class_loader);
1029 }
1030 assert(host_klass.not_null() || cp_patches == NULL,
1031 "cp_patches only found with host_klass");
1033 return k();
1034 }
1036 // Add a klass to the system from a stream (called by jni_DefineClass and
1037 // JVM_DefineClass).
1038 // Note: class_name can be NULL. In that case we do not know the name of
1039 // the class until we have parsed the stream.
1041 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1042 Handle class_loader,
1043 Handle protection_domain,
1044 ClassFileStream* st,
1045 bool verify,
1046 TRAPS) {
1048 // Classloaders that support parallelism, e.g. bootstrap classloader,
1049 // or all classloaders with UnsyncloadClass do not acquire lock here
1050 bool DoObjectLock = true;
1051 if (is_parallelCapable(class_loader)) {
1052 DoObjectLock = false;
1053 }
1055 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1057 // Make sure we are synchronized on the class loader before we proceed
1058 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1059 check_loader_lock_contention(lockObject, THREAD);
1060 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1062 TempNewSymbol parsed_name = NULL;
1064 // Parse the stream. Note that we do this even though this klass might
1065 // already be present in the SystemDictionary, otherwise we would not
1066 // throw potential ClassFormatErrors.
1067 //
1068 // Note: "name" is updated.
1070 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1071 loader_data,
1072 protection_domain,
1073 parsed_name,
1074 verify,
1075 THREAD);
1077 const char* pkg = "java/";
1078 if (!HAS_PENDING_EXCEPTION &&
1079 !class_loader.is_null() &&
1080 parsed_name != NULL &&
1081 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1082 // It is illegal to define classes in the "java." package from
1083 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1084 ResourceMark rm(THREAD);
1085 char* name = parsed_name->as_C_string();
1086 char* index = strrchr(name, '/');
1087 *index = '\0'; // chop to just the package name
1088 while ((index = strchr(name, '/')) != NULL) {
1089 *index = '.'; // replace '/' with '.' in package name
1090 }
1091 const char* fmt = "Prohibited package name: %s";
1092 size_t len = strlen(fmt) + strlen(name);
1093 char* message = NEW_RESOURCE_ARRAY(char, len);
1094 jio_snprintf(message, len, fmt, name);
1095 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1096 vmSymbols::java_lang_SecurityException(), message);
1097 }
1099 if (!HAS_PENDING_EXCEPTION) {
1100 assert(parsed_name != NULL, "Sanity");
1101 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1102 // Verification prevents us from creating names with dots in them, this
1103 // asserts that that's the case.
1104 assert(is_internal_format(parsed_name),
1105 "external class name format used internally");
1107 // Add class just loaded
1108 // If a class loader supports parallel classloading handle parallel define requests
1109 // find_or_define_instance_class may return a different InstanceKlass
1110 if (is_parallelCapable(class_loader)) {
1111 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1112 } else {
1113 define_instance_class(k, THREAD);
1114 }
1115 }
1117 // Make sure we have an entry in the SystemDictionary on success
1118 debug_only( {
1119 if (!HAS_PENDING_EXCEPTION) {
1120 assert(parsed_name != NULL, "parsed_name is still null?");
1121 Symbol* h_name = k->name();
1122 ClassLoaderData *defining_loader_data = k->class_loader_data();
1124 MutexLocker mu(SystemDictionary_lock, THREAD);
1126 Klass* check = find_class(parsed_name, loader_data);
1127 assert(check == k(), "should be present in the dictionary");
1129 Klass* check2 = find_class(h_name, defining_loader_data);
1130 assert(check == check2, "name inconsistancy in SystemDictionary");
1131 }
1132 } );
1134 return k();
1135 }
1138 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1139 int number_of_entries) {
1140 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1141 "bad shared dictionary size.");
1142 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1143 }
1146 // If there is a shared dictionary, then find the entry for the
1147 // given shared system class, if any.
1149 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1150 if (shared_dictionary() != NULL) {
1151 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1152 int d_index = shared_dictionary()->hash_to_index(d_hash);
1154 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1155 } else {
1156 return NULL;
1157 }
1158 }
1161 // Load a class from the shared spaces (found through the shared system
1162 // dictionary). Force the superclass and all interfaces to be loaded.
1163 // Update the class definition to include sibling classes and no
1164 // subclasses (yet). [Classes in the shared space are not part of the
1165 // object hierarchy until loaded.]
1167 instanceKlassHandle SystemDictionary::load_shared_class(
1168 Symbol* class_name, Handle class_loader, TRAPS) {
1169 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1170 return load_shared_class(ik, class_loader, THREAD);
1171 }
1173 instanceKlassHandle SystemDictionary::load_shared_class(
1174 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1175 assert(class_loader.is_null(), "non-null classloader for shared class?");
1176 if (ik.not_null()) {
1177 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1178 Symbol* class_name = ik->name();
1180 // Found the class, now load the superclass and interfaces. If they
1181 // are shared, add them to the main system dictionary and reset
1182 // their hierarchy references (supers, subs, and interfaces).
1184 if (ik->super() != NULL) {
1185 Symbol* cn = ik->super()->name();
1186 resolve_super_or_fail(class_name, cn,
1187 class_loader, Handle(), true, CHECK_(nh));
1188 }
1190 Array<Klass*>* interfaces = ik->local_interfaces();
1191 int num_interfaces = interfaces->length();
1192 for (int index = 0; index < num_interfaces; index++) {
1193 Klass* k = interfaces->at(index);
1195 // Note: can not use InstanceKlass::cast here because
1196 // interfaces' InstanceKlass's C++ vtbls haven't been
1197 // reinitialized yet (they will be once the interface classes
1198 // are loaded)
1199 Symbol* name = k->name();
1200 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1201 }
1203 // Adjust methods to recover missing data. They need addresses for
1204 // interpreter entry points and their default native method address
1205 // must be reset.
1207 // Updating methods must be done under a lock so multiple
1208 // threads don't update these in parallel
1209 // Shared classes are all currently loaded by the bootstrap
1210 // classloader, so this will never cause a deadlock on
1211 // a custom class loader lock.
1213 {
1214 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1215 check_loader_lock_contention(lockObject, THREAD);
1216 ObjectLocker ol(lockObject, THREAD, true);
1217 ik->restore_unshareable_info(CHECK_(nh));
1218 }
1220 if (TraceClassLoading) {
1221 ResourceMark rm;
1222 tty->print("[Loaded %s", ik->external_name());
1223 tty->print(" from shared objects file");
1224 tty->print_cr("]");
1225 }
1226 // notify a class loaded from shared object
1227 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1228 true /* shared class */);
1229 }
1230 return ik;
1231 }
1234 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1235 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1236 if (class_loader.is_null()) {
1238 // Search the shared system dictionary for classes preloaded into the
1239 // shared spaces.
1240 instanceKlassHandle k;
1241 {
1242 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1243 k = load_shared_class(class_name, class_loader, THREAD);
1244 }
1246 if (k.is_null()) {
1247 // Use VM class loader
1248 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1249 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1250 }
1252 // find_or_define_instance_class may return a different InstanceKlass
1253 if (!k.is_null()) {
1254 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1255 }
1256 return k;
1257 } else {
1258 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1259 ResourceMark rm(THREAD);
1261 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1262 JavaThread* jt = (JavaThread*) THREAD;
1264 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1265 ClassLoader::perf_app_classload_selftime(),
1266 ClassLoader::perf_app_classload_count(),
1267 jt->get_thread_stat()->perf_recursion_counts_addr(),
1268 jt->get_thread_stat()->perf_timers_addr(),
1269 PerfClassTraceTime::CLASS_LOAD);
1271 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1272 // Translate to external class name format, i.e., convert '/' chars to '.'
1273 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1275 JavaValue result(T_OBJECT);
1277 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1279 // Call public unsynchronized loadClass(String) directly for all class loaders
1280 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1281 // acquire a class-name based lock rather than the class loader object lock.
1282 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1283 // so the call to loadClassInternal() was not required.
1284 //
1285 // UnsyncloadClass flag means both call loadClass(String) and do
1286 // not acquire the class loader lock even for class loaders that are
1287 // not parallelCapable. This was a risky transitional
1288 // flag for diagnostic purposes only. It is risky to call
1289 // custom class loaders without synchronization.
1290 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1291 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1292 // Do NOT assume this will be supported in future releases.
1293 //
1294 // Added MustCallLoadClassInternal in case we discover in the field
1295 // a customer that counts on this call
1296 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1297 JavaCalls::call_special(&result,
1298 class_loader,
1299 spec_klass,
1300 vmSymbols::loadClassInternal_name(),
1301 vmSymbols::string_class_signature(),
1302 string,
1303 CHECK_(nh));
1304 } else {
1305 JavaCalls::call_virtual(&result,
1306 class_loader,
1307 spec_klass,
1308 vmSymbols::loadClass_name(),
1309 vmSymbols::string_class_signature(),
1310 string,
1311 CHECK_(nh));
1312 }
1314 assert(result.get_type() == T_OBJECT, "just checking");
1315 oop obj = (oop) result.get_jobject();
1317 // Primitive classes return null since forName() can not be
1318 // used to obtain any of the Class objects representing primitives or void
1319 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1320 instanceKlassHandle k =
1321 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1322 // For user defined Java class loaders, check that the name returned is
1323 // the same as that requested. This check is done for the bootstrap
1324 // loader when parsing the class file.
1325 if (class_name == k->name()) {
1326 return k;
1327 }
1328 }
1329 // Class is not found or has the wrong name, return NULL
1330 return nh;
1331 }
1332 }
1334 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1336 ClassLoaderData* loader_data = k->class_loader_data();
1337 Handle class_loader_h(THREAD, loader_data->class_loader());
1339 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1341 // for bootstrap and other parallel classloaders don't acquire lock,
1342 // use placeholder token
1343 // If a parallelCapable class loader calls define_instance_class instead of
1344 // find_or_define_instance_class to get here, we have a timing
1345 // hole with systemDictionary updates and check_constraints
1346 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1347 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1348 compute_loader_lock_object(class_loader_h, THREAD)),
1349 "define called without lock");
1350 }
1352 // Check class-loading constraints. Throw exception if violation is detected.
1353 // Grabs and releases SystemDictionary_lock
1354 // The check_constraints/find_class call and update_dictionary sequence
1355 // must be "atomic" for a specific class/classloader pair so we never
1356 // define two different instanceKlasses for that class/classloader pair.
1357 // Existing classloaders will call define_instance_class with the
1358 // classloader lock held
1359 // Parallel classloaders will call find_or_define_instance_class
1360 // which will require a token to perform the define class
1361 Symbol* name_h = k->name();
1362 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1363 int d_index = dictionary()->hash_to_index(d_hash);
1364 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1366 // Register class just loaded with class loader (placed in Vector)
1367 // Note we do this before updating the dictionary, as this can
1368 // fail with an OutOfMemoryError (if it does, we will *not* put this
1369 // class in the dictionary and will not update the class hierarchy).
1370 // JVMTI FollowReferences needs to find the classes this way.
1371 if (k->class_loader() != NULL) {
1372 methodHandle m(THREAD, Universe::loader_addClass_method());
1373 JavaValue result(T_VOID);
1374 JavaCallArguments args(class_loader_h);
1375 args.push_oop(Handle(THREAD, k->java_mirror()));
1376 JavaCalls::call(&result, m, &args, CHECK);
1377 }
1379 // Add the new class. We need recompile lock during update of CHA.
1380 {
1381 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1382 int p_index = placeholders()->hash_to_index(p_hash);
1384 MutexLocker mu_r(Compile_lock, THREAD);
1386 // Add to class hierarchy, initialize vtables, and do possible
1387 // deoptimizations.
1388 add_to_hierarchy(k, CHECK); // No exception, but can block
1390 // Add to systemDictionary - so other classes can see it.
1391 // Grabs and releases SystemDictionary_lock
1392 update_dictionary(d_index, d_hash, p_index, p_hash,
1393 k, class_loader_h, THREAD);
1394 }
1395 k->eager_initialize(THREAD);
1397 // notify jvmti
1398 if (JvmtiExport::should_post_class_load()) {
1399 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1400 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1402 }
1404 }
1406 // Support parallel classloading
1407 // All parallel class loaders, including bootstrap classloader
1408 // lock a placeholder entry for this class/class_loader pair
1409 // to allow parallel defines of different classes for this class loader
1410 // With AllowParallelDefine flag==true, in case they do not synchronize around
1411 // FindLoadedClass/DefineClass, calls, we check for parallel
1412 // loading for them, wait if a defineClass is in progress
1413 // and return the initial requestor's results
1414 // This flag does not apply to the bootstrap classloader.
1415 // With AllowParallelDefine flag==false, call through to define_instance_class
1416 // which will throw LinkageError: duplicate class definition.
1417 // False is the requested default.
1418 // For better performance, the class loaders should synchronize
1419 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1420 // potentially waste time reading and parsing the bytestream.
1421 // Note: VM callers should ensure consistency of k/class_name,class_loader
1422 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1424 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1425 Symbol* name_h = k->name(); // passed in class_name may be null
1426 ClassLoaderData* loader_data = class_loader_data(class_loader);
1428 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1429 int d_index = dictionary()->hash_to_index(d_hash);
1431 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1432 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1433 int p_index = placeholders()->hash_to_index(p_hash);
1434 PlaceholderEntry* probe;
1436 {
1437 MutexLocker mu(SystemDictionary_lock, THREAD);
1438 // First check if class already defined
1439 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1440 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1441 if (check != NULL) {
1442 return(instanceKlassHandle(THREAD, check));
1443 }
1444 }
1446 // Acquire define token for this class/classloader
1447 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1448 // Wait if another thread defining in parallel
1449 // All threads wait - even those that will throw duplicate class: otherwise
1450 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1451 // if other thread has not finished updating dictionary
1452 while (probe->definer() != NULL) {
1453 SystemDictionary_lock->wait();
1454 }
1455 // Only special cases allow parallel defines and can use other thread's results
1456 // Other cases fall through, and may run into duplicate defines
1457 // caught by finding an entry in the SystemDictionary
1458 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1459 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1460 SystemDictionary_lock->notify_all();
1461 #ifdef ASSERT
1462 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1463 assert(check != NULL, "definer missed recording success");
1464 #endif
1465 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1466 } else {
1467 // This thread will define the class (even if earlier thread tried and had an error)
1468 probe->set_definer(THREAD);
1469 }
1470 }
1472 define_instance_class(k, THREAD);
1474 Handle linkage_exception = Handle(); // null handle
1476 // definer must notify any waiting threads
1477 {
1478 MutexLocker mu(SystemDictionary_lock, THREAD);
1479 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1480 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1481 if (probe != NULL) {
1482 if (HAS_PENDING_EXCEPTION) {
1483 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1484 CLEAR_PENDING_EXCEPTION;
1485 } else {
1486 probe->set_instance_klass(k());
1487 }
1488 probe->set_definer(NULL);
1489 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1490 SystemDictionary_lock->notify_all();
1491 }
1492 }
1494 // Can't throw exception while holding lock due to rank ordering
1495 if (linkage_exception() != NULL) {
1496 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1497 }
1499 return k;
1500 }
1501 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1502 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1503 if (class_loader.is_null()) {
1504 return Handle(THREAD, _system_loader_lock_obj);
1505 } else {
1506 return class_loader;
1507 }
1508 }
1510 // This method is added to check how often we have to wait to grab loader
1511 // lock. The results are being recorded in the performance counters defined in
1512 // ClassLoader::_sync_systemLoaderLockContentionRate and
1513 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1514 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1515 if (!UsePerfData) {
1516 return;
1517 }
1519 assert(!loader_lock.is_null(), "NULL lock object");
1521 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1522 == ObjectSynchronizer::owner_other) {
1523 // contention will likely happen, so increment the corresponding
1524 // contention counter.
1525 if (loader_lock() == _system_loader_lock_obj) {
1526 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1527 } else {
1528 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1529 }
1530 }
1531 }
1533 // ----------------------------------------------------------------------------
1534 // Lookup
1536 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1537 Symbol* class_name,
1538 ClassLoaderData* loader_data) {
1539 assert_locked_or_safepoint(SystemDictionary_lock);
1540 assert (index == dictionary()->index_for(class_name, loader_data),
1541 "incorrect index?");
1543 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1544 return k;
1545 }
1548 // Basic find on classes in the midst of being loaded
1549 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1550 ClassLoaderData* loader_data) {
1551 assert_locked_or_safepoint(SystemDictionary_lock);
1552 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1553 int p_index = placeholders()->hash_to_index(p_hash);
1554 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1555 }
1558 // Used for assertions and verification only
1559 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1560 #ifndef ASSERT
1561 guarantee(VerifyBeforeGC ||
1562 VerifyDuringGC ||
1563 VerifyBeforeExit ||
1564 VerifyDuringStartup ||
1565 VerifyAfterGC, "too expensive");
1566 #endif
1567 assert_locked_or_safepoint(SystemDictionary_lock);
1569 // First look in the loaded class array
1570 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1571 int d_index = dictionary()->hash_to_index(d_hash);
1572 return find_class(d_index, d_hash, class_name, loader_data);
1573 }
1576 // Get the next class in the diictionary.
1577 Klass* SystemDictionary::try_get_next_class() {
1578 return dictionary()->try_get_next_class();
1579 }
1582 // ----------------------------------------------------------------------------
1583 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1584 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1585 // before a new class is used.
1587 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1588 assert(k.not_null(), "just checking");
1589 assert_locked_or_safepoint(Compile_lock);
1591 // Link into hierachy. Make sure the vtables are initialized before linking into
1592 k->append_to_sibling_list(); // add to superklass/sibling list
1593 k->process_interfaces(THREAD); // handle all "implements" declarations
1594 k->set_init_state(InstanceKlass::loaded);
1595 // Now flush all code that depended on old class hierarchy.
1596 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1597 // Also, first reinitialize vtable because it may have gotten out of synch
1598 // while the new class wasn't connected to the class hierarchy.
1599 Universe::flush_dependents_on(k);
1600 }
1603 // ----------------------------------------------------------------------------
1604 // GC support
1606 // Following roots during mark-sweep is separated in two phases.
1607 //
1608 // The first phase follows preloaded classes and all other system
1609 // classes, since these will never get unloaded anyway.
1610 //
1611 // The second phase removes (unloads) unreachable classes from the
1612 // system dictionary and follows the remaining classes' contents.
1614 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1615 blk->do_oop(&_java_system_loader);
1616 blk->do_oop(&_system_loader_lock_obj);
1618 dictionary()->always_strong_oops_do(blk);
1620 // Visit extra methods
1621 invoke_method_table()->oops_do(blk);
1622 }
1624 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1625 // Follow all system classes and temporary placeholders in dictionary
1626 dictionary()->always_strong_classes_do(closure);
1628 // Placeholders. These represent classes we're actively loading.
1629 placeholders()->classes_do(closure);
1630 }
1632 // Calculate a "good" systemdictionary size based
1633 // on predicted or current loaded classes count
1634 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1635 int newsize = _old_default_sdsize;
1636 if ((classcount > 0) && !DumpSharedSpaces) {
1637 int desiredsize = classcount/_average_depth_goal;
1638 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1639 newsize = _primelist[++_sdgeneration]) {
1640 if (desiredsize <= newsize) {
1641 break;
1642 }
1643 }
1644 }
1645 return newsize;
1646 }
1648 #ifdef ASSERT
1649 class VerifySDReachableAndLiveClosure : public OopClosure {
1650 private:
1651 BoolObjectClosure* _is_alive;
1653 template <class T> void do_oop_work(T* p) {
1654 oop obj = oopDesc::load_decode_heap_oop(p);
1655 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1656 }
1658 public:
1659 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1661 virtual void do_oop(oop* p) { do_oop_work(p); }
1662 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1663 };
1664 #endif
1666 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1667 // Note: anonymous classes are not in the SD.
1668 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1669 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1670 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1671 bool unloading_occurred = false;
1672 if (has_dead_loaders) {
1673 unloading_occurred = dictionary()->do_unloading();
1674 constraints()->purge_loader_constraints();
1675 resolution_errors()->purge_resolution_errors();
1676 }
1677 // Oops referenced by the system dictionary may get unreachable independently
1678 // of the class loader (eg. cached protection domain oops). So we need to
1679 // explicitly unlink them here instead of in Dictionary::do_unloading.
1680 dictionary()->unlink(is_alive);
1681 #ifdef ASSERT
1682 VerifySDReachableAndLiveClosure cl(is_alive);
1683 dictionary()->oops_do(&cl);
1684 #endif
1685 return unloading_occurred;
1686 }
1688 void SystemDictionary::oops_do(OopClosure* f) {
1689 f->do_oop(&_java_system_loader);
1690 f->do_oop(&_system_loader_lock_obj);
1692 // Adjust dictionary
1693 dictionary()->oops_do(f);
1695 // Visit extra methods
1696 invoke_method_table()->oops_do(f);
1697 }
1699 // Extended Class redefinition support.
1700 // If one of these classes is replaced, we need to replace it in these places.
1701 // KlassClosure::do_klass should take the address of a class but we can
1702 // change that later.
1703 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1704 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1705 f->do_klass(_well_known_klasses[k]);
1706 }
1708 {
1709 for (int i = 0; i < T_VOID+1; i++) {
1710 if (_box_klasses[i] != NULL) {
1711 assert(i >= T_BOOLEAN, "checking");
1712 f->do_klass(_box_klasses[i]);
1713 }
1714 }
1715 }
1717 FilteredFieldsMap::classes_do(f);
1718 }
1720 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1721 f->do_klass(_abstract_ownable_synchronizer_klass);
1722 }
1724 // Just the classes from defining class loaders
1725 // Don't iterate over placeholders
1726 void SystemDictionary::classes_do(void f(Klass*)) {
1727 dictionary()->classes_do(f);
1728 }
1730 // Added for initialize_itable_for_klass
1731 // Just the classes from defining class loaders
1732 // Don't iterate over placeholders
1733 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1734 dictionary()->classes_do(f, CHECK);
1735 }
1737 // All classes, and their class loaders
1738 // Don't iterate over placeholders
1739 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1740 dictionary()->classes_do(f);
1741 }
1743 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1744 placeholders()->entries_do(f);
1745 }
1747 void SystemDictionary::methods_do(void f(Method*)) {
1748 dictionary()->methods_do(f);
1749 invoke_method_table()->methods_do(f);
1750 }
1752 // ----------------------------------------------------------------------------
1753 // Lazily load klasses
1755 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1756 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1758 // if multiple threads calling this function, only one thread will load
1759 // the class. The other threads will find the loaded version once the
1760 // class is loaded.
1761 Klass* aos = _abstract_ownable_synchronizer_klass;
1762 if (aos == NULL) {
1763 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1764 // Force a fence to prevent any read before the write completes
1765 OrderAccess::fence();
1766 _abstract_ownable_synchronizer_klass = k;
1767 }
1768 }
1770 // ----------------------------------------------------------------------------
1771 // Initialization
1773 void SystemDictionary::initialize(TRAPS) {
1774 // Allocate arrays
1775 assert(dictionary() == NULL,
1776 "SystemDictionary should only be initialized once");
1777 _sdgeneration = 0;
1778 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1779 _placeholders = new PlaceholderTable(_nof_buckets);
1780 _number_of_modifications = 0;
1781 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1782 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1783 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1785 // Allocate private object used as system class loader lock
1786 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1787 // Initialize basic classes
1788 initialize_preloaded_classes(CHECK);
1789 }
1791 // Compact table of directions on the initialization of klasses:
1792 static const short wk_init_info[] = {
1793 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1794 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1795 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1796 | (int)SystemDictionary::option ),
1797 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1798 #undef WK_KLASS_INIT_INFO
1799 0
1800 };
1802 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1803 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1804 int info = wk_init_info[id - FIRST_WKID];
1805 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1806 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1807 Klass** klassp = &_well_known_klasses[id];
1808 bool must_load = (init_opt < SystemDictionary::Opt);
1809 if ((*klassp) == NULL) {
1810 if (must_load) {
1811 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1812 } else {
1813 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1814 }
1815 }
1816 return ((*klassp) != NULL);
1817 }
1819 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1820 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1821 for (int id = (int)start_id; id < (int)limit_id; id++) {
1822 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1823 int info = wk_init_info[id - FIRST_WKID];
1824 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1825 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1827 initialize_wk_klass((WKID)id, opt, CHECK);
1828 }
1830 // move the starting value forward to the limit:
1831 start_id = limit_id;
1832 }
1834 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1835 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1836 // Preload commonly used klasses
1837 WKID scan = FIRST_WKID;
1838 // first do Object, then String, Class
1839 if (UseSharedSpaces) {
1840 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1841 // Initialize the constant pool for the Object_class
1842 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1843 ik->constants()->restore_unshareable_info(CHECK);
1844 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1845 } else {
1846 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1847 }
1849 // Calculate offsets for String and Class classes since they are loaded and
1850 // can be used after this point.
1851 java_lang_String::compute_offsets();
1852 java_lang_Class::compute_offsets();
1854 // Fixup mirrors for classes loaded before java.lang.Class.
1855 // These calls iterate over the objects currently in the perm gen
1856 // so calling them at this point is matters (not before when there
1857 // are fewer objects and not later after there are more objects
1858 // in the perm gen.
1859 Universe::initialize_basic_type_mirrors(CHECK);
1860 Universe::fixup_mirrors(CHECK);
1862 // do a bunch more:
1863 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1865 // Preload ref klasses and set reference types
1866 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1867 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1869 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1870 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1871 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1872 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1873 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1875 // JSR 292 classes
1876 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1877 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1878 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1879 if (EnableInvokeDynamic) {
1880 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1881 } else {
1882 // Skip the JSR 292 classes, if not enabled.
1883 scan = WKID(jsr292_group_end + 1);
1884 }
1886 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1888 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1889 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1890 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1891 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1892 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1893 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1894 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1895 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1896 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1897 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1899 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1900 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1901 _has_loadClassInternal = (method != NULL);
1902 }
1903 { // Compute whether we should use checkPackageAccess or NOT
1904 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1905 _has_checkPackageAccess = (method != NULL);
1906 }
1907 }
1909 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1910 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1911 BasicType SystemDictionary::box_klass_type(Klass* k) {
1912 assert(k != NULL, "");
1913 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1914 if (_box_klasses[i] == k)
1915 return (BasicType)i;
1916 }
1917 return T_OBJECT;
1918 }
1920 // Constraints on class loaders. The details of the algorithm can be
1921 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1922 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1923 // that the system dictionary needs to maintain a set of contraints that
1924 // must be satisfied by all classes in the dictionary.
1925 // if defining is true, then LinkageError if already in systemDictionary
1926 // if initiating loader, then ok if InstanceKlass matches existing entry
1928 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1929 instanceKlassHandle k,
1930 Handle class_loader, bool defining,
1931 TRAPS) {
1932 const char *linkage_error = NULL;
1933 {
1934 Symbol* name = k->name();
1935 ClassLoaderData *loader_data = class_loader_data(class_loader);
1937 MutexLocker mu(SystemDictionary_lock, THREAD);
1939 Klass* check = find_class(d_index, d_hash, name, loader_data);
1940 if (check != (Klass*)NULL) {
1941 // if different InstanceKlass - duplicate class definition,
1942 // else - ok, class loaded by a different thread in parallel,
1943 // we should only have found it if it was done loading and ok to use
1944 // system dictionary only holds instance classes, placeholders
1945 // also holds array classes
1947 assert(check->oop_is_instance(), "noninstance in systemdictionary");
1948 if ((defining == true) || (k() != check)) {
1949 linkage_error = "loader (instance of %s): attempted duplicate class "
1950 "definition for name: \"%s\"";
1951 } else {
1952 return;
1953 }
1954 }
1956 #ifdef ASSERT
1957 Symbol* ph_check = find_placeholder(name, loader_data);
1958 assert(ph_check == NULL || ph_check == name, "invalid symbol");
1959 #endif
1961 if (linkage_error == NULL) {
1962 if (constraints()->check_or_update(k, class_loader, name) == false) {
1963 linkage_error = "loader constraint violation: loader (instance of %s)"
1964 " previously initiated loading for a different type with name \"%s\"";
1965 }
1966 }
1967 }
1969 // Throw error now if needed (cannot throw while holding
1970 // SystemDictionary_lock because of rank ordering)
1972 if (linkage_error) {
1973 ResourceMark rm(THREAD);
1974 const char* class_loader_name = loader_name(class_loader());
1975 char* type_name = k->name()->as_C_string();
1976 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1977 strlen(type_name);
1978 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1979 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1980 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1981 }
1982 }
1985 // Update system dictionary - done after check_constraint and add_to_hierachy
1986 // have been called.
1987 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1988 int p_index, unsigned int p_hash,
1989 instanceKlassHandle k,
1990 Handle class_loader,
1991 TRAPS) {
1992 // Compile_lock prevents systemDictionary updates during compilations
1993 assert_locked_or_safepoint(Compile_lock);
1994 Symbol* name = k->name();
1995 ClassLoaderData *loader_data = class_loader_data(class_loader);
1997 {
1998 MutexLocker mu1(SystemDictionary_lock, THREAD);
2000 // See whether biased locking is enabled and if so set it for this
2001 // klass.
2002 // Note that this must be done past the last potential blocking
2003 // point / safepoint. We enable biased locking lazily using a
2004 // VM_Operation to iterate the SystemDictionary and installing the
2005 // biasable mark word into each InstanceKlass's prototype header.
2006 // To avoid race conditions where we accidentally miss enabling the
2007 // optimization for one class in the process of being added to the
2008 // dictionary, we must not safepoint after the test of
2009 // BiasedLocking::enabled().
2010 if (UseBiasedLocking && BiasedLocking::enabled()) {
2011 // Set biased locking bit for all loaded classes; it will be
2012 // cleared if revocation occurs too often for this type
2013 // NOTE that we must only do this when the class is initally
2014 // defined, not each time it is referenced from a new class loader
2015 if (k->class_loader() == class_loader()) {
2016 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2017 }
2018 }
2020 // Make a new system dictionary entry.
2021 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2022 if (sd_check == NULL) {
2023 dictionary()->add_klass(name, loader_data, k);
2024 notice_modification();
2025 }
2026 #ifdef ASSERT
2027 sd_check = find_class(d_index, d_hash, name, loader_data);
2028 assert (sd_check != NULL, "should have entry in system dictionary");
2029 // Note: there may be a placeholder entry: for circularity testing
2030 // or for parallel defines
2031 #endif
2032 SystemDictionary_lock->notify_all();
2033 }
2034 }
2037 // Try to find a class name using the loader constraints. The
2038 // loader constraints might know about a class that isn't fully loaded
2039 // yet and these will be ignored.
2040 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2041 Symbol* class_name, Handle class_loader, TRAPS) {
2043 // First see if it has been loaded directly.
2044 // Force the protection domain to be null. (This removes protection checks.)
2045 Handle no_protection_domain;
2046 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2047 no_protection_domain, CHECK_NULL);
2048 if (klass != NULL)
2049 return klass;
2051 // Now look to see if it has been loaded elsewhere, and is subject to
2052 // a loader constraint that would require this loader to return the
2053 // klass that is already loaded.
2054 if (FieldType::is_array(class_name)) {
2055 // For array classes, their Klass*s are not kept in the
2056 // constraint table. The element Klass*s are.
2057 FieldArrayInfo fd;
2058 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2059 if (t != T_OBJECT) {
2060 klass = Universe::typeArrayKlassObj(t);
2061 } else {
2062 MutexLocker mu(SystemDictionary_lock, THREAD);
2063 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2064 }
2065 // If element class already loaded, allocate array klass
2066 if (klass != NULL) {
2067 klass = klass->array_klass_or_null(fd.dimension());
2068 }
2069 } else {
2070 MutexLocker mu(SystemDictionary_lock, THREAD);
2071 // Non-array classes are easy: simply check the constraint table.
2072 klass = constraints()->find_constrained_klass(class_name, class_loader);
2073 }
2075 return klass;
2076 }
2079 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2080 Handle class_loader1,
2081 Handle class_loader2,
2082 Thread* THREAD) {
2083 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2084 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2086 Symbol* constraint_name = NULL;
2087 if (!FieldType::is_array(class_name)) {
2088 constraint_name = class_name;
2089 } else {
2090 // For array classes, their Klass*s are not kept in the
2091 // constraint table. The element classes are.
2092 FieldArrayInfo fd;
2093 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2094 // primitive types always pass
2095 if (t != T_OBJECT) {
2096 return true;
2097 } else {
2098 constraint_name = fd.object_key();
2099 }
2100 }
2101 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2102 int d_index1 = dictionary()->hash_to_index(d_hash1);
2104 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2105 int d_index2 = dictionary()->hash_to_index(d_hash2);
2106 {
2107 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2109 // Better never do a GC while we're holding these oops
2110 No_Safepoint_Verifier nosafepoint;
2112 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2113 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2114 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2115 klass2, class_loader2);
2116 }
2117 }
2119 // Add entry to resolution error table to record the error when the first
2120 // attempt to resolve a reference to a class has failed.
2121 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2122 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2123 int index = resolution_errors()->hash_to_index(hash);
2124 {
2125 MutexLocker ml(SystemDictionary_lock, Thread::current());
2126 resolution_errors()->add_entry(index, hash, pool, which, error);
2127 }
2128 }
2130 // Delete a resolution error for RedefineClasses for a constant pool is going away
2131 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2132 resolution_errors()->delete_entry(pool);
2133 }
2135 // Lookup resolution error table. Returns error if found, otherwise NULL.
2136 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2137 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2138 int index = resolution_errors()->hash_to_index(hash);
2139 {
2140 MutexLocker ml(SystemDictionary_lock, Thread::current());
2141 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2142 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2143 }
2144 }
2147 // Signature constraints ensure that callers and callees agree about
2148 // the meaning of type names in their signatures. This routine is the
2149 // intake for constraints. It collects them from several places:
2150 //
2151 // * LinkResolver::resolve_method (if check_access is true) requires
2152 // that the resolving class (the caller) and the defining class of
2153 // the resolved method (the callee) agree on each type in the
2154 // method's signature.
2155 //
2156 // * LinkResolver::resolve_interface_method performs exactly the same
2157 // checks.
2158 //
2159 // * LinkResolver::resolve_field requires that the constant pool
2160 // attempting to link to a field agree with the field's defining
2161 // class about the type of the field signature.
2162 //
2163 // * klassVtable::initialize_vtable requires that, when a class
2164 // overrides a vtable entry allocated by a superclass, that the
2165 // overriding method (i.e., the callee) agree with the superclass
2166 // on each type in the method's signature.
2167 //
2168 // * klassItable::initialize_itable requires that, when a class fills
2169 // in its itables, for each non-abstract method installed in an
2170 // itable, the method (i.e., the callee) agree with the interface
2171 // on each type in the method's signature.
2172 //
2173 // All those methods have a boolean (check_access, checkconstraints)
2174 // which turns off the checks. This is used from specialized contexts
2175 // such as bootstrapping, dumping, and debugging.
2176 //
2177 // No direct constraint is placed between the class and its
2178 // supertypes. Constraints are only placed along linked relations
2179 // between callers and callees. When a method overrides or implements
2180 // an abstract method in a supertype (superclass or interface), the
2181 // constraints are placed as if the supertype were the caller to the
2182 // overriding method. (This works well, since callers to the
2183 // supertype have already established agreement between themselves and
2184 // the supertype.) As a result of all this, a class can disagree with
2185 // its supertype about the meaning of a type name, as long as that
2186 // class neither calls a relevant method of the supertype, nor is
2187 // called (perhaps via an override) from the supertype.
2188 //
2189 //
2190 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2191 //
2192 // Make sure all class components (including arrays) in the given
2193 // signature will be resolved to the same class in both loaders.
2194 // Returns the name of the type that failed a loader constraint check, or
2195 // NULL if no constraint failed. No exception except OOME is thrown.
2196 // Arrays are not added to the loader constraint table, their elements are.
2197 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2198 Handle loader1, Handle loader2,
2199 bool is_method, TRAPS) {
2200 // Nothing to do if loaders are the same.
2201 if (loader1() == loader2()) {
2202 return NULL;
2203 }
2205 SignatureStream sig_strm(signature, is_method);
2206 while (!sig_strm.is_done()) {
2207 if (sig_strm.is_object()) {
2208 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2209 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2210 return sig;
2211 }
2212 }
2213 sig_strm.next();
2214 }
2215 return NULL;
2216 }
2219 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2220 Symbol* signature,
2221 TRAPS) {
2222 methodHandle empty;
2223 assert(EnableInvokeDynamic, "");
2224 assert(MethodHandles::is_signature_polymorphic(iid) &&
2225 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2226 iid != vmIntrinsics::_invokeGeneric,
2227 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2229 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2230 int index = invoke_method_table()->hash_to_index(hash);
2231 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2232 methodHandle m;
2233 if (spe == NULL || spe->method() == NULL) {
2234 spe = NULL;
2235 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2236 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2237 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2238 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2240 // Now grab the lock. We might have to throw away the new method,
2241 // if a racing thread has managed to install one at the same time.
2242 {
2243 MutexLocker ml(SystemDictionary_lock, THREAD);
2244 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2245 if (spe == NULL)
2246 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2247 if (spe->method() == NULL)
2248 spe->set_method(m());
2249 }
2250 }
2252 assert(spe != NULL && spe->method() != NULL, "");
2253 return spe->method();
2254 }
2256 // Helper for unpacking the return value from linkMethod and linkCallSite.
2257 static methodHandle unpack_method_and_appendix(Handle mname,
2258 KlassHandle accessing_klass,
2259 objArrayHandle appendix_box,
2260 Handle* appendix_result,
2261 TRAPS) {
2262 methodHandle empty;
2263 if (mname.not_null()) {
2264 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2265 if (vmtarget != NULL && vmtarget->is_method()) {
2266 Method* m = (Method*)vmtarget;
2267 oop appendix = appendix_box->obj_at(0);
2268 if (TraceMethodHandles) {
2269 #ifndef PRODUCT
2270 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2271 m->print();
2272 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2273 tty->cr();
2274 #endif //PRODUCT
2275 }
2276 (*appendix_result) = Handle(THREAD, appendix);
2277 // the target is stored in the cpCache and if a reference to this
2278 // MethodName is dropped we need a way to make sure the
2279 // class_loader containing this method is kept alive.
2280 // FIXME: the appendix might also preserve this dependency.
2281 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2282 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2283 return methodHandle(THREAD, m);
2284 }
2285 }
2286 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2287 return empty;
2288 }
2290 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2291 Symbol* signature,
2292 KlassHandle accessing_klass,
2293 Handle *appendix_result,
2294 Handle *method_type_result,
2295 TRAPS) {
2296 methodHandle empty;
2297 assert(EnableInvokeDynamic, "");
2298 assert(!THREAD->is_Compiler_thread(), "");
2299 Handle method_type =
2300 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2301 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2302 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2303 }
2305 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2306 int ref_kind = JVM_REF_invokeVirtual;
2307 Handle name_str = StringTable::intern(name, CHECK_(empty));
2308 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2309 assert(appendix_box->obj_at(0) == NULL, "");
2311 // This should not happen. JDK code should take care of that.
2312 if (accessing_klass.is_null() || method_type.is_null()) {
2313 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2314 }
2316 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2317 JavaCallArguments args;
2318 args.push_oop(accessing_klass()->java_mirror());
2319 args.push_int(ref_kind);
2320 args.push_oop(mh_klass()->java_mirror());
2321 args.push_oop(name_str());
2322 args.push_oop(method_type());
2323 args.push_oop(appendix_box());
2324 JavaValue result(T_OBJECT);
2325 JavaCalls::call_static(&result,
2326 SystemDictionary::MethodHandleNatives_klass(),
2327 vmSymbols::linkMethod_name(),
2328 vmSymbols::linkMethod_signature(),
2329 &args, CHECK_(empty));
2330 Handle mname(THREAD, (oop) result.get_jobject());
2331 (*method_type_result) = method_type;
2332 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2333 }
2336 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2337 // signature, as interpreted relative to the given class loader.
2338 // Because of class loader constraints, all method handle usage must be
2339 // consistent with this loader.
2340 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2341 KlassHandle accessing_klass,
2342 TRAPS) {
2343 Handle empty;
2344 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2345 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2346 int index = invoke_method_table()->hash_to_index(hash);
2347 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2348 if (spe != NULL && spe->method_type() != NULL) {
2349 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2350 return Handle(THREAD, spe->method_type());
2351 } else if (THREAD->is_Compiler_thread()) {
2352 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2353 return Handle(); // do not attempt from within compiler, unless it was cached
2354 }
2356 Handle class_loader, protection_domain;
2357 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2358 int npts = ArgumentCount(signature).size();
2359 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2360 int arg = 0;
2361 Handle rt; // the return type from the signature
2362 ResourceMark rm(THREAD);
2363 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2364 oop mirror = NULL;
2365 if (is_on_bcp) {
2366 // Note: class_loader & protection_domain are both null at this point.
2367 mirror = ss.as_java_mirror(class_loader, protection_domain,
2368 SignatureStream::ReturnNull, CHECK_(empty));
2369 if (mirror == NULL) {
2370 // fall back from BCP to accessing_klass
2371 if (accessing_klass.not_null()) {
2372 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2373 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2374 }
2375 is_on_bcp = false;
2376 }
2377 }
2378 if (!is_on_bcp) {
2379 // Resolve, throwing a real error if it doesn't work.
2380 mirror = ss.as_java_mirror(class_loader, protection_domain,
2381 SignatureStream::NCDFError, CHECK_(empty));
2382 }
2383 if (ss.at_return_type())
2384 rt = Handle(THREAD, mirror);
2385 else
2386 pts->obj_at_put(arg++, mirror);
2388 // Check accessibility.
2389 if (ss.is_object() && accessing_klass.not_null()) {
2390 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2391 mirror = NULL; // safety
2392 // Emulate ConstantPool::verify_constant_pool_resolve.
2393 if (sel_klass->oop_is_objArray())
2394 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2395 if (sel_klass->oop_is_instance()) {
2396 KlassHandle sel_kh(THREAD, sel_klass);
2397 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2398 }
2399 }
2400 }
2401 assert(arg == npts, "");
2403 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2404 JavaCallArguments args(Handle(THREAD, rt()));
2405 args.push_oop(pts());
2406 JavaValue result(T_OBJECT);
2407 JavaCalls::call_static(&result,
2408 SystemDictionary::MethodHandleNatives_klass(),
2409 vmSymbols::findMethodHandleType_name(),
2410 vmSymbols::findMethodHandleType_signature(),
2411 &args, CHECK_(empty));
2412 Handle method_type(THREAD, (oop) result.get_jobject());
2414 if (is_on_bcp) {
2415 // We can cache this MethodType inside the JVM.
2416 MutexLocker ml(SystemDictionary_lock, THREAD);
2417 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2418 if (spe == NULL)
2419 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2420 if (spe->method_type() == NULL) {
2421 spe->set_method_type(method_type());
2422 }
2423 }
2425 // report back to the caller with the MethodType
2426 return method_type;
2427 }
2429 // Ask Java code to find or construct a method handle constant.
2430 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2431 int ref_kind, //e.g., JVM_REF_invokeVirtual
2432 KlassHandle callee,
2433 Symbol* name_sym,
2434 Symbol* signature,
2435 TRAPS) {
2436 Handle empty;
2437 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2438 Handle type;
2439 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2440 type = find_method_handle_type(signature, caller, CHECK_(empty));
2441 } else if (caller.is_null()) {
2442 // This should not happen. JDK code should take care of that.
2443 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2444 } else {
2445 ResourceMark rm(THREAD);
2446 SignatureStream ss(signature, false);
2447 if (!ss.is_done()) {
2448 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2449 SignatureStream::NCDFError, CHECK_(empty));
2450 type = Handle(THREAD, mirror);
2451 ss.next();
2452 if (!ss.is_done()) type = Handle(); // error!
2453 }
2454 }
2455 if (type.is_null()) {
2456 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2457 }
2459 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2460 JavaCallArguments args;
2461 args.push_oop(caller->java_mirror()); // the referring class
2462 args.push_int(ref_kind);
2463 args.push_oop(callee->java_mirror()); // the target class
2464 args.push_oop(name());
2465 args.push_oop(type());
2466 JavaValue result(T_OBJECT);
2467 JavaCalls::call_static(&result,
2468 SystemDictionary::MethodHandleNatives_klass(),
2469 vmSymbols::linkMethodHandleConstant_name(),
2470 vmSymbols::linkMethodHandleConstant_signature(),
2471 &args, CHECK_(empty));
2472 return Handle(THREAD, (oop) result.get_jobject());
2473 }
2475 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2476 // name and signature, as interpreted relative to the given class loader.
2477 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2478 Handle bootstrap_specifier,
2479 Symbol* name,
2480 Symbol* type,
2481 Handle *appendix_result,
2482 Handle *method_type_result,
2483 TRAPS) {
2484 methodHandle empty;
2485 Handle bsm, info;
2486 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2487 bsm = bootstrap_specifier;
2488 } else {
2489 assert(bootstrap_specifier->is_objArray(), "");
2490 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2491 int len = args->length();
2492 assert(len >= 1, "");
2493 bsm = Handle(THREAD, args->obj_at(0));
2494 if (len > 1) {
2495 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2496 for (int i = 1; i < len; i++)
2497 args1->obj_at_put(i-1, args->obj_at(i));
2498 info = Handle(THREAD, args1);
2499 }
2500 }
2501 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2502 "caller must supply a valid BSM");
2504 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2505 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2507 // This should not happen. JDK code should take care of that.
2508 if (caller.is_null() || method_type.is_null()) {
2509 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2510 }
2512 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2513 assert(appendix_box->obj_at(0) == NULL, "");
2515 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2516 JavaCallArguments args;
2517 args.push_oop(caller->java_mirror());
2518 args.push_oop(bsm());
2519 args.push_oop(method_name());
2520 args.push_oop(method_type());
2521 args.push_oop(info());
2522 args.push_oop(appendix_box);
2523 JavaValue result(T_OBJECT);
2524 JavaCalls::call_static(&result,
2525 SystemDictionary::MethodHandleNatives_klass(),
2526 vmSymbols::linkCallSite_name(),
2527 vmSymbols::linkCallSite_signature(),
2528 &args, CHECK_(empty));
2529 Handle mname(THREAD, (oop) result.get_jobject());
2530 (*method_type_result) = method_type;
2531 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2532 }
2534 // Since the identity hash code for symbols changes when the symbols are
2535 // moved from the regular perm gen (hash in the mark word) to the shared
2536 // spaces (hash is the address), the classes loaded into the dictionary
2537 // may be in the wrong buckets.
2539 void SystemDictionary::reorder_dictionary() {
2540 dictionary()->reorder_dictionary();
2541 }
2544 void SystemDictionary::copy_buckets(char** top, char* end) {
2545 dictionary()->copy_buckets(top, end);
2546 }
2549 void SystemDictionary::copy_table(char** top, char* end) {
2550 dictionary()->copy_table(top, end);
2551 }
2554 void SystemDictionary::reverse() {
2555 dictionary()->reverse();
2556 }
2558 int SystemDictionary::number_of_classes() {
2559 return dictionary()->number_of_entries();
2560 }
2563 // ----------------------------------------------------------------------------
2564 #ifndef PRODUCT
2566 void SystemDictionary::print() {
2567 dictionary()->print();
2569 // Placeholders
2570 GCMutexLocker mu(SystemDictionary_lock);
2571 placeholders()->print();
2573 // loader constraints - print under SD_lock
2574 constraints()->print();
2575 }
2577 #endif
2579 void SystemDictionary::verify() {
2580 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2581 guarantee(constraints() != NULL,
2582 "Verify of loader constraints failed");
2583 guarantee(dictionary()->number_of_entries() >= 0 &&
2584 placeholders()->number_of_entries() >= 0,
2585 "Verify of system dictionary failed");
2587 // Verify dictionary
2588 dictionary()->verify();
2590 GCMutexLocker mu(SystemDictionary_lock);
2591 placeholders()->verify();
2593 // Verify constraint table
2594 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2595 constraints()->verify(dictionary(), placeholders());
2596 }
2598 // utility function for class load event
2599 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2600 instanceKlassHandle k,
2601 Handle initiating_loader) {
2602 #if INCLUDE_TRACE
2603 EventClassLoad event(UNTIMED);
2604 if (event.should_commit()) {
2605 event.set_starttime(start_time);
2606 event.set_loadedClass(k());
2607 oop defining_class_loader = k->class_loader();
2608 event.set_definingClassLoader(defining_class_loader != NULL ?
2609 defining_class_loader->klass() : (Klass*)NULL);
2610 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2611 event.set_initiatingClassLoader(class_loader != NULL ?
2612 class_loader->klass() : (Klass*)NULL);
2613 event.commit();
2614 }
2615 #endif /* INCLUDE_TRACE */
2616 }
2618 #ifndef PRODUCT
2620 // statistics code
2621 class ClassStatistics: AllStatic {
2622 private:
2623 static int nclasses; // number of classes
2624 static int nmethods; // number of methods
2625 static int nmethoddata; // number of methodData
2626 static int class_size; // size of class objects in words
2627 static int method_size; // size of method objects in words
2628 static int debug_size; // size of debug info in methods
2629 static int methoddata_size; // size of methodData objects in words
2631 static void do_class(Klass* k) {
2632 nclasses++;
2633 class_size += k->size();
2634 if (k->oop_is_instance()) {
2635 InstanceKlass* ik = (InstanceKlass*)k;
2636 class_size += ik->methods()->size();
2637 class_size += ik->constants()->size();
2638 class_size += ik->local_interfaces()->size();
2639 class_size += ik->transitive_interfaces()->size();
2640 // We do not have to count implementors, since we only store one!
2641 // SSS: How should these be accounted now that they have moved?
2642 // class_size += ik->fields()->length();
2643 }
2644 }
2646 static void do_method(Method* m) {
2647 nmethods++;
2648 method_size += m->size();
2649 // class loader uses same objArray for empty vectors, so don't count these
2650 if (m->has_stackmap_table()) {
2651 method_size += m->stackmap_data()->size();
2652 }
2654 MethodData* mdo = m->method_data();
2655 if (mdo != NULL) {
2656 nmethoddata++;
2657 methoddata_size += mdo->size();
2658 }
2659 }
2661 public:
2662 static void print() {
2663 SystemDictionary::classes_do(do_class);
2664 SystemDictionary::methods_do(do_method);
2665 tty->print_cr("Class statistics:");
2666 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2667 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2668 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2669 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2670 }
2671 };
2674 int ClassStatistics::nclasses = 0;
2675 int ClassStatistics::nmethods = 0;
2676 int ClassStatistics::nmethoddata = 0;
2677 int ClassStatistics::class_size = 0;
2678 int ClassStatistics::method_size = 0;
2679 int ClassStatistics::debug_size = 0;
2680 int ClassStatistics::methoddata_size = 0;
2682 void SystemDictionary::print_class_statistics() {
2683 ResourceMark rm;
2684 ClassStatistics::print();
2685 }
2688 class MethodStatistics: AllStatic {
2689 public:
2690 enum {
2691 max_parameter_size = 10
2692 };
2693 private:
2695 static int _number_of_methods;
2696 static int _number_of_final_methods;
2697 static int _number_of_static_methods;
2698 static int _number_of_native_methods;
2699 static int _number_of_synchronized_methods;
2700 static int _number_of_profiled_methods;
2701 static int _number_of_bytecodes;
2702 static int _parameter_size_profile[max_parameter_size];
2703 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2705 static void initialize() {
2706 _number_of_methods = 0;
2707 _number_of_final_methods = 0;
2708 _number_of_static_methods = 0;
2709 _number_of_native_methods = 0;
2710 _number_of_synchronized_methods = 0;
2711 _number_of_profiled_methods = 0;
2712 _number_of_bytecodes = 0;
2713 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2714 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2715 };
2717 static void do_method(Method* m) {
2718 _number_of_methods++;
2719 // collect flag info
2720 if (m->is_final() ) _number_of_final_methods++;
2721 if (m->is_static() ) _number_of_static_methods++;
2722 if (m->is_native() ) _number_of_native_methods++;
2723 if (m->is_synchronized()) _number_of_synchronized_methods++;
2724 if (m->method_data() != NULL) _number_of_profiled_methods++;
2725 // collect parameter size info (add one for receiver, if any)
2726 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2727 // collect bytecodes info
2728 {
2729 Thread *thread = Thread::current();
2730 HandleMark hm(thread);
2731 BytecodeStream s(methodHandle(thread, m));
2732 Bytecodes::Code c;
2733 while ((c = s.next()) >= 0) {
2734 _number_of_bytecodes++;
2735 _bytecodes_profile[c]++;
2736 }
2737 }
2738 }
2740 public:
2741 static void print() {
2742 initialize();
2743 SystemDictionary::methods_do(do_method);
2744 // generate output
2745 tty->cr();
2746 tty->print_cr("Method statistics (static):");
2747 // flag distribution
2748 tty->cr();
2749 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2750 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2751 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2752 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2753 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2754 // parameter size profile
2755 tty->cr();
2756 { int tot = 0;
2757 int avg = 0;
2758 for (int i = 0; i < max_parameter_size; i++) {
2759 int n = _parameter_size_profile[i];
2760 tot += n;
2761 avg += n*i;
2762 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2763 }
2764 assert(tot == _number_of_methods, "should be the same");
2765 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2766 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2767 }
2768 // bytecodes profile
2769 tty->cr();
2770 { int tot = 0;
2771 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2772 if (Bytecodes::is_defined(i)) {
2773 Bytecodes::Code c = Bytecodes::cast(i);
2774 int n = _bytecodes_profile[c];
2775 tot += n;
2776 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2777 }
2778 }
2779 assert(tot == _number_of_bytecodes, "should be the same");
2780 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2781 }
2782 tty->cr();
2783 }
2784 };
2786 int MethodStatistics::_number_of_methods;
2787 int MethodStatistics::_number_of_final_methods;
2788 int MethodStatistics::_number_of_static_methods;
2789 int MethodStatistics::_number_of_native_methods;
2790 int MethodStatistics::_number_of_synchronized_methods;
2791 int MethodStatistics::_number_of_profiled_methods;
2792 int MethodStatistics::_number_of_bytecodes;
2793 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2794 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2797 void SystemDictionary::print_method_statistics() {
2798 MethodStatistics::print();
2799 }
2801 #endif // PRODUCT