Mercurial > hg > truffle
annotate src/share/vm/classfile/systemDictionary.cpp @ 618:ae1579717a57
6812428: G1: Error: assert(ret || obj_in_cs(obj),"sanity")
Summary: The length of the fast cset test vector is decided at the beginning of a GC, but more regions can be added during the GC. The simple fix is to set the length of the fast cset test vector to the max.
Reviewed-by: iveresov
author | tonyp |
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date | Sat, 07 Mar 2009 11:07:37 -0500 |
parents | dca06e7f503d |
children | 0fbdb4381b99 |
rev | line source |
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0 | 1 /* |
196 | 2 * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved. |
0 | 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_systemDictionary.cpp.incl" | |
27 | |
28 | |
29 Dictionary* SystemDictionary::_dictionary = NULL; | |
30 PlaceholderTable* SystemDictionary::_placeholders = NULL; | |
31 Dictionary* SystemDictionary::_shared_dictionary = NULL; | |
32 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; | |
33 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; | |
34 | |
35 | |
36 int SystemDictionary::_number_of_modifications = 0; | |
37 | |
38 oop SystemDictionary::_system_loader_lock_obj = NULL; | |
39 | |
132
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40 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] |
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41 = { NULL /*, NULL...*/ }; |
0 | 42 |
43 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; | |
44 | |
45 oop SystemDictionary::_java_system_loader = NULL; | |
46 | |
47 bool SystemDictionary::_has_loadClassInternal = false; | |
48 bool SystemDictionary::_has_checkPackageAccess = false; | |
49 | |
50 // lazily initialized klass variables | |
51 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; | |
52 | |
53 | |
54 // ---------------------------------------------------------------------------- | |
55 // Java-level SystemLoader | |
56 | |
57 oop SystemDictionary::java_system_loader() { | |
58 return _java_system_loader; | |
59 } | |
60 | |
61 void SystemDictionary::compute_java_system_loader(TRAPS) { | |
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62 KlassHandle system_klass(THREAD, WK_KLASS(classloader_klass)); |
0 | 63 JavaValue result(T_OBJECT); |
64 JavaCalls::call_static(&result, | |
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65 KlassHandle(THREAD, WK_KLASS(classloader_klass)), |
0 | 66 vmSymbolHandles::getSystemClassLoader_name(), |
67 vmSymbolHandles::void_classloader_signature(), | |
68 CHECK); | |
69 | |
70 _java_system_loader = (oop)result.get_jobject(); | |
71 } | |
72 | |
73 | |
74 // ---------------------------------------------------------------------------- | |
75 // debugging | |
76 | |
77 #ifdef ASSERT | |
78 | |
79 // return true if class_name contains no '.' (internal format is '/') | |
80 bool SystemDictionary::is_internal_format(symbolHandle class_name) { | |
81 if (class_name.not_null()) { | |
82 ResourceMark rm; | |
83 char* name = class_name->as_C_string(); | |
84 return strchr(name, '.') == NULL; | |
85 } else { | |
86 return true; | |
87 } | |
88 } | |
89 | |
90 #endif | |
91 | |
92 // ---------------------------------------------------------------------------- | |
514 | 93 // Parallel class loading check |
94 | |
95 bool SystemDictionary::is_parallelCapable(Handle class_loader) { | |
96 if (UnsyncloadClass || class_loader.is_null()) return true; | |
97 if (AlwaysLockClassLoader) return false; | |
98 return java_lang_Class::parallelCapable(class_loader()); | |
99 } | |
100 // ---------------------------------------------------------------------------- | |
0 | 101 // Resolving of classes |
102 | |
103 // Forwards to resolve_or_null | |
104 | |
105 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { | |
106 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); | |
107 if (HAS_PENDING_EXCEPTION || klass == NULL) { | |
108 KlassHandle k_h(THREAD, klass); | |
109 // can return a null klass | |
110 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); | |
111 } | |
112 return klass; | |
113 } | |
114 | |
115 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) { | |
116 if (HAS_PENDING_EXCEPTION) { | |
117 // If we have a pending exception we forward it to the caller, unless throw_error is true, | |
118 // in which case we have to check whether the pending exception is a ClassNotFoundException, | |
119 // and if so convert it to a NoClassDefFoundError | |
120 // And chain the original ClassNotFoundException | |
121 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) { | |
122 ResourceMark rm(THREAD); | |
123 assert(klass_h() == NULL, "Should not have result with exception pending"); | |
124 Handle e(THREAD, PENDING_EXCEPTION); | |
125 CLEAR_PENDING_EXCEPTION; | |
126 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); | |
127 } else { | |
128 return NULL; | |
129 } | |
130 } | |
131 // Class not found, throw appropriate error or exception depending on value of throw_error | |
132 if (klass_h() == NULL) { | |
133 ResourceMark rm(THREAD); | |
134 if (throw_error) { | |
135 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); | |
136 } else { | |
137 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); | |
138 } | |
139 } | |
140 return (klassOop)klass_h(); | |
141 } | |
142 | |
143 | |
144 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, | |
145 bool throw_error, TRAPS) | |
146 { | |
147 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); | |
148 } | |
149 | |
150 | |
151 // Forwards to resolve_instance_class_or_null | |
152 | |
153 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { | |
154 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread"); | |
155 if (FieldType::is_array(class_name())) { | |
156 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); | |
157 } else { | |
158 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); | |
159 } | |
160 } | |
161 | |
162 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) { | |
163 return resolve_or_null(class_name, Handle(), Handle(), THREAD); | |
164 } | |
165 | |
166 // Forwards to resolve_instance_class_or_null | |
167 | |
168 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name, | |
169 Handle class_loader, | |
170 Handle protection_domain, | |
171 TRAPS) { | |
172 assert(FieldType::is_array(class_name()), "must be array"); | |
173 jint dimension; | |
174 symbolOop object_key; | |
175 klassOop k = NULL; | |
176 // dimension and object_key are assigned as a side-effect of this call | |
177 BasicType t = FieldType::get_array_info(class_name(), | |
178 &dimension, | |
179 &object_key, | |
180 CHECK_NULL); | |
181 | |
182 if (t == T_OBJECT) { | |
183 symbolHandle h_key(THREAD, object_key); | |
184 // naked oop "k" is OK here -- we assign back into it | |
185 k = SystemDictionary::resolve_instance_class_or_null(h_key, | |
186 class_loader, | |
187 protection_domain, | |
188 CHECK_NULL); | |
189 if (k != NULL) { | |
190 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL); | |
191 } | |
192 } else { | |
193 k = Universe::typeArrayKlassObj(t); | |
194 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL); | |
195 } | |
196 return k; | |
197 } | |
198 | |
199 | |
200 // Must be called for any super-class or super-interface resolution | |
201 // during class definition to allow class circularity checking | |
202 // super-interface callers: | |
203 // parse_interfaces - for defineClass & jvmtiRedefineClasses | |
204 // super-class callers: | |
205 // ClassFileParser - for defineClass & jvmtiRedefineClasses | |
206 // load_shared_class - while loading a class from shared archive | |
514 | 207 // resolve_instance_class_or_null: |
208 // via: handle_parallel_super_load | |
0 | 209 // when resolving a class that has an existing placeholder with |
210 // a saved superclass [i.e. a defineClass is currently in progress] | |
211 // if another thread is trying to resolve the class, it must do | |
212 // super-class checks on its own thread to catch class circularity | |
213 // This last call is critical in class circularity checking for cases | |
214 // where classloading is delegated to different threads and the | |
215 // classloader lock is released. | |
216 // Take the case: Base->Super->Base | |
217 // 1. If thread T1 tries to do a defineClass of class Base | |
218 // resolve_super_or_fail creates placeholder: T1, Base (super Super) | |
219 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super | |
220 // so it tries to load Super | |
221 // 3. If we load the class internally, or user classloader uses same thread | |
222 // loadClassFromxxx or defineClass via parseClassFile Super ... | |
223 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) | |
224 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base | |
225 // 3.4 calls resolve_super_or_fail Base | |
226 // 3.5 finds T1,Base -> throws class circularity | |
227 //OR 4. If T2 tries to resolve Super via defineClass Super ... | |
228 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) | |
229 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) | |
230 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 | |
231 // 4.4 finds T2, Super -> throws class circularity | |
232 // Must be called, even if superclass is null, since this is | |
233 // where the placeholder entry is created which claims this | |
234 // thread is loading this class/classloader. | |
235 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name, | |
236 symbolHandle class_name, | |
237 Handle class_loader, | |
238 Handle protection_domain, | |
239 bool is_superclass, | |
240 TRAPS) { | |
241 | |
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242 // Try to get one of the well-known klasses. |
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243 // They are trusted, and do not participate in circularities. |
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244 if (LinkWellKnownClasses) { |
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245 klassOop k = find_well_known_klass(class_name()); |
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246 if (k != NULL) { |
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247 return k; |
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248 } |
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249 } |
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250 |
0 | 251 // Double-check, if child class is already loaded, just return super-class,interface |
252 // Don't add a placedholder if already loaded, i.e. already in system dictionary | |
253 // Make sure there's a placeholder for the *child* before resolving. | |
254 // Used as a claim that this thread is currently loading superclass/classloader | |
255 // Used here for ClassCircularity checks and also for heap verification | |
256 // (every instanceKlass in the heap needs to be in the system dictionary | |
257 // or have a placeholder). | |
258 // Must check ClassCircularity before checking if super class is already loaded | |
259 // | |
260 // We might not already have a placeholder if this child_name was | |
261 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); | |
262 // the name of the class might not be known until the stream is actually | |
263 // parsed. | |
264 // Bugs 4643874, 4715493 | |
265 // compute_hash can have a safepoint | |
266 | |
267 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader); | |
268 int d_index = dictionary()->hash_to_index(d_hash); | |
269 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader); | |
270 int p_index = placeholders()->hash_to_index(p_hash); | |
271 // can't throw error holding a lock | |
272 bool child_already_loaded = false; | |
273 bool throw_circularity_error = false; | |
274 { | |
275 MutexLocker mu(SystemDictionary_lock, THREAD); | |
276 klassOop childk = find_class(d_index, d_hash, child_name, class_loader); | |
277 klassOop quicksuperk; | |
278 // to support // loading: if child done loading, just return superclass | |
279 // if class_name, & class_loader don't match: | |
280 // if initial define, SD update will give LinkageError | |
281 // if redefine: compare_class_versions will give HIERARCHY_CHANGED | |
282 // so we don't throw an exception here. | |
283 // see: nsk redefclass014 & java.lang.instrument Instrument032 | |
284 if ((childk != NULL ) && (is_superclass) && | |
285 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) && | |
286 | |
287 ((Klass::cast(quicksuperk)->name() == class_name()) && | |
288 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) { | |
289 return quicksuperk; | |
290 } else { | |
291 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); | |
292 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { | |
293 throw_circularity_error = true; | |
294 } | |
514 | 295 } |
296 if (!throw_circularity_error) { | |
0 | 297 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD); |
298 } | |
299 } | |
300 if (throw_circularity_error) { | |
301 ResourceMark rm(THREAD); | |
302 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); | |
303 } | |
304 | |
305 // java.lang.Object should have been found above | |
306 assert(class_name() != NULL, "null super class for resolving"); | |
307 // Resolve the super class or interface, check results on return | |
308 klassOop superk = NULL; | |
309 superk = SystemDictionary::resolve_or_null(class_name, | |
310 class_loader, | |
311 protection_domain, | |
312 THREAD); | |
313 | |
314 KlassHandle superk_h(THREAD, superk); | |
315 | |
316 // Note: clean up of placeholders currently in callers of | |
317 // resolve_super_or_fail - either at update_dictionary time | |
318 // or on error | |
319 { | |
320 MutexLocker mu(SystemDictionary_lock, THREAD); | |
321 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); | |
322 if (probe != NULL) { | |
323 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER); | |
324 } | |
325 } | |
326 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { | |
327 // can null superk | |
328 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); | |
329 } | |
330 | |
331 return superk_h(); | |
332 } | |
333 | |
334 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, | |
335 Handle class_loader, | |
336 Handle protection_domain, | |
337 TRAPS) { | |
338 if(!has_checkPackageAccess()) return; | |
339 | |
340 // Now we have to call back to java to check if the initating class has access | |
341 JavaValue result(T_VOID); | |
342 if (TraceProtectionDomainVerification) { | |
343 // Print out trace information | |
344 tty->print_cr("Checking package access"); | |
345 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); | |
346 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); | |
347 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); | |
348 } | |
349 | |
350 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader"); | |
351 | |
352 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass()); | |
353 JavaCalls::call_special(&result, | |
354 class_loader, | |
355 system_loader, | |
356 vmSymbolHandles::checkPackageAccess_name(), | |
357 vmSymbolHandles::class_protectiondomain_signature(), | |
358 Handle(THREAD, klass->java_mirror()), | |
359 protection_domain, | |
360 THREAD); | |
361 | |
362 if (TraceProtectionDomainVerification) { | |
363 if (HAS_PENDING_EXCEPTION) { | |
364 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); | |
365 } else { | |
366 tty->print_cr(" -> granted"); | |
367 } | |
368 tty->cr(); | |
369 } | |
370 | |
371 if (HAS_PENDING_EXCEPTION) return; | |
372 | |
373 // If no exception has been thrown, we have validated the protection domain | |
374 // Insert the protection domain of the initiating class into the set. | |
375 { | |
376 // We recalculate the entry here -- we've called out to java since | |
377 // the last time it was calculated. | |
378 symbolHandle kn(THREAD, klass->name()); | |
379 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader); | |
380 int d_index = dictionary()->hash_to_index(d_hash); | |
381 | |
382 MutexLocker mu(SystemDictionary_lock, THREAD); | |
383 { | |
384 // Note that we have an entry, and entries can be deleted only during GC, | |
385 // so we cannot allow GC to occur while we're holding this entry. | |
386 | |
387 // We're using a No_Safepoint_Verifier to catch any place where we | |
388 // might potentially do a GC at all. | |
389 // SystemDictionary::do_unloading() asserts that classes are only | |
390 // unloaded at a safepoint. | |
391 No_Safepoint_Verifier nosafepoint; | |
392 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader, | |
393 protection_domain, THREAD); | |
394 } | |
395 } | |
396 } | |
397 | |
398 // We only get here if this thread finds that another thread | |
399 // has already claimed the placeholder token for the current operation, | |
400 // but that other thread either never owned or gave up the | |
401 // object lock | |
402 // Waits on SystemDictionary_lock to indicate placeholder table updated | |
403 // On return, caller must recheck placeholder table state | |
404 // | |
405 // We only get here if | |
406 // 1) custom classLoader, i.e. not bootstrap classloader | |
407 // 2) UnsyncloadClass not set | |
408 // 3) custom classLoader has broken the class loader objectLock | |
409 // so another thread got here in parallel | |
410 // | |
411 // lockObject must be held. | |
412 // Complicated dance due to lock ordering: | |
413 // Must first release the classloader object lock to | |
414 // allow initial definer to complete the class definition | |
415 // and to avoid deadlock | |
416 // Reclaim classloader lock object with same original recursion count | |
417 // Must release SystemDictionary_lock after notify, since | |
418 // class loader lock must be claimed before SystemDictionary_lock | |
419 // to prevent deadlocks | |
420 // | |
421 // The notify allows applications that did an untimed wait() on | |
422 // the classloader object lock to not hang. | |
423 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { | |
424 assert_lock_strong(SystemDictionary_lock); | |
425 | |
426 bool calledholdinglock | |
427 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); | |
428 assert(calledholdinglock,"must hold lock for notify"); | |
514 | 429 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); |
0 | 430 ObjectSynchronizer::notifyall(lockObject, THREAD); |
431 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); | |
432 SystemDictionary_lock->wait(); | |
433 SystemDictionary_lock->unlock(); | |
434 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); | |
435 SystemDictionary_lock->lock(); | |
436 } | |
437 | |
438 // If the class in is in the placeholder table, class loading is in progress | |
439 // For cases where the application changes threads to load classes, it | |
440 // is critical to ClassCircularity detection that we try loading | |
441 // the superclass on the same thread internally, so we do parallel | |
442 // super class loading here. | |
443 // This also is critical in cases where the original thread gets stalled | |
444 // even in non-circularity situations. | |
445 // Note: only one thread can define the class, but multiple can resolve | |
446 // Note: must call resolve_super_or_fail even if null super - | |
514 | 447 // to force placeholder entry creation for this class for circularity detection |
0 | 448 // Caller must check for pending exception |
449 // Returns non-null klassOop if other thread has completed load | |
450 // and we are done, | |
451 // If return null klassOop and no pending exception, the caller must load the class | |
452 instanceKlassHandle SystemDictionary::handle_parallel_super_load( | |
453 symbolHandle name, symbolHandle superclassname, Handle class_loader, | |
454 Handle protection_domain, Handle lockObject, TRAPS) { | |
455 | |
456 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
457 unsigned int d_hash = dictionary()->compute_hash(name, class_loader); | |
458 int d_index = dictionary()->hash_to_index(d_hash); | |
459 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); | |
460 int p_index = placeholders()->hash_to_index(p_hash); | |
461 | |
462 // superk is not used, resolve_super called for circularity check only | |
463 // This code is reached in two situations. One if this thread | |
464 // is loading the same class twice (e.g. ClassCircularity, or | |
465 // java.lang.instrument). | |
466 // The second is if another thread started the resolve_super first | |
467 // and has not yet finished. | |
468 // In both cases the original caller will clean up the placeholder | |
469 // entry on error. | |
470 klassOop superk = SystemDictionary::resolve_super_or_fail(name, | |
471 superclassname, | |
472 class_loader, | |
473 protection_domain, | |
474 true, | |
475 CHECK_(nh)); | |
476 // We don't redefine the class, so we just need to clean up if there | |
477 // was not an error (don't want to modify any system dictionary | |
478 // data structures). | |
479 { | |
480 MutexLocker mu(SystemDictionary_lock, THREAD); | |
481 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
482 SystemDictionary_lock->notify_all(); | |
483 } | |
484 | |
514 | 485 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete |
486 // Serial class loaders and bootstrap classloader do wait for superclass loads | |
487 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { | |
0 | 488 MutexLocker mu(SystemDictionary_lock, THREAD); |
489 // Check if classloading completed while we were loading superclass or waiting | |
490 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
491 if (check != NULL) { | |
492 // Klass is already loaded, so just return it | |
493 return(instanceKlassHandle(THREAD, check)); | |
494 } else { | |
495 return nh; | |
496 } | |
497 } | |
498 | |
499 // must loop to both handle other placeholder updates | |
500 // and spurious notifications | |
501 bool super_load_in_progress = true; | |
502 PlaceholderEntry* placeholder; | |
503 while (super_load_in_progress) { | |
504 MutexLocker mu(SystemDictionary_lock, THREAD); | |
505 // Check if classloading completed while we were loading superclass or waiting | |
506 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
507 if (check != NULL) { | |
508 // Klass is already loaded, so just return it | |
509 return(instanceKlassHandle(THREAD, check)); | |
510 } else { | |
511 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
512 if (placeholder && placeholder->super_load_in_progress() ){ | |
513 // Before UnsyncloadClass: | |
514 // We only get here if the application has released the | |
515 // classloader lock when another thread was in the middle of loading a | |
516 // superclass/superinterface for this class, and now | |
517 // this thread is also trying to load this class. | |
518 // To minimize surprises, the first thread that started to | |
519 // load a class should be the one to complete the loading | |
520 // with the classfile it initially expected. | |
521 // This logic has the current thread wait once it has done | |
522 // all the superclass/superinterface loading it can, until | |
523 // the original thread completes the class loading or fails | |
524 // If it completes we will use the resulting instanceKlass | |
525 // which we will find below in the systemDictionary. | |
526 // We also get here for parallel bootstrap classloader | |
527 if (class_loader.is_null()) { | |
528 SystemDictionary_lock->wait(); | |
529 } else { | |
530 double_lock_wait(lockObject, THREAD); | |
531 } | |
532 } else { | |
533 // If not in SD and not in PH, other thread's load must have failed | |
534 super_load_in_progress = false; | |
535 } | |
536 } | |
537 } | |
538 return (nh); | |
539 } | |
540 | |
541 | |
542 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { | |
543 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name"); | |
544 // First check to see if we should remove wrapping L and ; | |
545 symbolHandle name; | |
546 if (FieldType::is_obj(class_name())) { | |
547 ResourceMark rm(THREAD); | |
548 // Ignore wrapping L and ;. | |
549 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL); | |
550 } else { | |
551 name = class_name; | |
552 } | |
553 | |
554 // UseNewReflection | |
555 // Fix for 4474172; see evaluation for more details | |
556 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); | |
557 | |
558 // Do lookup to see if class already exist and the protection domain | |
559 // has the right access | |
560 unsigned int d_hash = dictionary()->compute_hash(name, class_loader); | |
561 int d_index = dictionary()->hash_to_index(d_hash); | |
562 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader, | |
563 protection_domain, THREAD); | |
564 if (probe != NULL) return probe; | |
565 | |
566 | |
567 // Non-bootstrap class loaders will call out to class loader and | |
568 // define via jvm/jni_DefineClass which will acquire the | |
569 // class loader object lock to protect against multiple threads | |
570 // defining the class in parallel by accident. | |
571 // This lock must be acquired here so the waiter will find | |
572 // any successful result in the SystemDictionary and not attempt | |
573 // the define | |
514 | 574 // ParallelCapable Classloaders and the bootstrap classloader, |
0 | 575 // or all classloaders with UnsyncloadClass do not acquire lock here |
576 bool DoObjectLock = true; | |
514 | 577 if (is_parallelCapable(class_loader)) { |
0 | 578 DoObjectLock = false; |
579 } | |
580 | |
581 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); | |
582 int p_index = placeholders()->hash_to_index(p_hash); | |
583 | |
584 // Class is not in SystemDictionary so we have to do loading. | |
585 // Make sure we are synchronized on the class loader before we proceed | |
586 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); | |
587 check_loader_lock_contention(lockObject, THREAD); | |
588 ObjectLocker ol(lockObject, THREAD, DoObjectLock); | |
589 | |
590 // Check again (after locking) if class already exist in SystemDictionary | |
591 bool class_has_been_loaded = false; | |
592 bool super_load_in_progress = false; | |
593 bool havesupername = false; | |
594 instanceKlassHandle k; | |
595 PlaceholderEntry* placeholder; | |
596 symbolHandle superclassname; | |
597 | |
598 { | |
599 MutexLocker mu(SystemDictionary_lock, THREAD); | |
600 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
601 if (check != NULL) { | |
602 // Klass is already loaded, so just return it | |
603 class_has_been_loaded = true; | |
604 k = instanceKlassHandle(THREAD, check); | |
605 } else { | |
606 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
607 if (placeholder && placeholder->super_load_in_progress()) { | |
608 super_load_in_progress = true; | |
609 if (placeholder->havesupername() == true) { | |
610 superclassname = symbolHandle(THREAD, placeholder->supername()); | |
611 havesupername = true; | |
612 } | |
613 } | |
614 } | |
615 } | |
616 | |
617 // If the class in is in the placeholder table, class loading is in progress | |
618 if (super_load_in_progress && havesupername==true) { | |
619 k = SystemDictionary::handle_parallel_super_load(name, superclassname, | |
620 class_loader, protection_domain, lockObject, THREAD); | |
621 if (HAS_PENDING_EXCEPTION) { | |
622 return NULL; | |
623 } | |
624 if (!k.is_null()) { | |
625 class_has_been_loaded = true; | |
626 } | |
627 } | |
628 | |
629 if (!class_has_been_loaded) { | |
630 | |
631 // add placeholder entry to record loading instance class | |
632 // Five cases: | |
633 // All cases need to prevent modifying bootclasssearchpath | |
634 // in parallel with a classload of same classname | |
514 | 635 // Redefineclasses uses existence of the placeholder for the duration |
636 // of the class load to prevent concurrent redefinition of not completely | |
637 // defined classes. | |
0 | 638 // case 1. traditional classloaders that rely on the classloader object lock |
639 // - no other need for LOAD_INSTANCE | |
640 // case 2. traditional classloaders that break the classloader object lock | |
641 // as a deadlock workaround. Detection of this case requires that | |
642 // this check is done while holding the classloader object lock, | |
643 // and that lock is still held when calling classloader's loadClass. | |
644 // For these classloaders, we ensure that the first requestor | |
645 // completes the load and other requestors wait for completion. | |
646 // case 3. UnsyncloadClass - don't use objectLocker | |
647 // With this flag, we allow parallel classloading of a | |
648 // class/classloader pair | |
649 // case4. Bootstrap classloader - don't own objectLocker | |
650 // This classloader supports parallelism at the classloader level, | |
651 // but only allows a single load of a class/classloader pair. | |
652 // No performance benefit and no deadlock issues. | |
514 | 653 // case 5. parallelCapable user level classloaders - without objectLocker |
654 // Allow parallel classloading of a class/classloader pair | |
0 | 655 symbolHandle nullsymbolHandle; |
656 bool throw_circularity_error = false; | |
657 { | |
658 MutexLocker mu(SystemDictionary_lock, THREAD); | |
514 | 659 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { |
0 | 660 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); |
661 if (oldprobe) { | |
662 // only need check_seen_thread once, not on each loop | |
663 // 6341374 java/lang/Instrument with -Xcomp | |
664 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { | |
665 throw_circularity_error = true; | |
666 } else { | |
667 // case 1: traditional: should never see load_in_progress. | |
668 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { | |
669 | |
670 // case 4: bootstrap classloader: prevent futile classloading, | |
671 // wait on first requestor | |
672 if (class_loader.is_null()) { | |
673 SystemDictionary_lock->wait(); | |
674 } else { | |
675 // case 2: traditional with broken classloader lock. wait on first | |
676 // requestor. | |
677 double_lock_wait(lockObject, THREAD); | |
678 } | |
679 // Check if classloading completed while we were waiting | |
680 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
681 if (check != NULL) { | |
682 // Klass is already loaded, so just return it | |
683 k = instanceKlassHandle(THREAD, check); | |
684 class_has_been_loaded = true; | |
685 } | |
686 // check if other thread failed to load and cleaned up | |
687 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
688 } | |
689 } | |
690 } | |
691 } | |
692 // All cases: add LOAD_INSTANCE | |
514 | 693 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try |
0 | 694 // LOAD_INSTANCE in parallel |
695 // add placeholder entry even if error - callers will remove on error | |
514 | 696 if (!throw_circularity_error && !class_has_been_loaded) { |
0 | 697 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD); |
698 // For class loaders that do not acquire the classloader object lock, | |
699 // if they did not catch another thread holding LOAD_INSTANCE, | |
700 // need a check analogous to the acquire ObjectLocker/find_class | |
701 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL | |
702 // one final check if the load has already completed | |
514 | 703 // class loaders holding the ObjectLock shouldn't find the class here |
0 | 704 klassOop check = find_class(d_index, d_hash, name, class_loader); |
705 if (check != NULL) { | |
706 // Klass is already loaded, so just return it | |
707 k = instanceKlassHandle(THREAD, check); | |
708 class_has_been_loaded = true; | |
709 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); | |
514 | 710 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); |
711 SystemDictionary_lock->notify_all(); | |
0 | 712 } |
713 } | |
714 } | |
715 // must throw error outside of owning lock | |
716 if (throw_circularity_error) { | |
717 ResourceMark rm(THREAD); | |
718 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); | |
719 } | |
720 | |
721 if (!class_has_been_loaded) { | |
722 | |
723 // Do actual loading | |
724 k = load_instance_class(name, class_loader, THREAD); | |
725 | |
514 | 726 // For UnsyncloadClass and AllowParallelDefineClass only: |
0 | 727 // If they got a linkageError, check if a parallel class load succeeded. |
728 // If it did, then for bytecode resolution the specification requires | |
729 // that we return the same result we did for the other thread, i.e. the | |
730 // successfully loaded instanceKlass | |
731 // Should not get here for classloaders that support parallelism | |
514 | 732 // with the new cleaner mechanism |
733 // Bootstrap goes through here to allow for an extra guarantee check | |
0 | 734 if (UnsyncloadClass || (class_loader.is_null())) { |
735 if (k.is_null() && HAS_PENDING_EXCEPTION | |
736 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) { | |
737 MutexLocker mu(SystemDictionary_lock, THREAD); | |
738 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
739 if (check != NULL) { | |
740 // Klass is already loaded, so just use it | |
741 k = instanceKlassHandle(THREAD, check); | |
742 CLEAR_PENDING_EXCEPTION; | |
743 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); | |
744 } | |
745 } | |
746 } | |
747 | |
748 // clean up placeholder entries for success or error | |
749 // This cleans up LOAD_INSTANCE entries | |
750 // It also cleans up LOAD_SUPER entries on errors from | |
751 // calling load_instance_class | |
752 { | |
753 MutexLocker mu(SystemDictionary_lock, THREAD); | |
754 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
755 if (probe != NULL) { | |
756 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); | |
757 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
758 SystemDictionary_lock->notify_all(); | |
759 } | |
760 } | |
761 | |
762 // If everything was OK (no exceptions, no null return value), and | |
763 // class_loader is NOT the defining loader, do a little more bookkeeping. | |
764 if (!HAS_PENDING_EXCEPTION && !k.is_null() && | |
765 k->class_loader() != class_loader()) { | |
766 | |
767 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); | |
768 | |
769 // Need to check for a PENDING_EXCEPTION again; check_constraints | |
770 // can throw and doesn't use the CHECK macro. | |
771 if (!HAS_PENDING_EXCEPTION) { | |
772 { // Grabbing the Compile_lock prevents systemDictionary updates | |
773 // during compilations. | |
774 MutexLocker mu(Compile_lock, THREAD); | |
775 update_dictionary(d_index, d_hash, p_index, p_hash, | |
776 k, class_loader, THREAD); | |
777 } | |
778 if (JvmtiExport::should_post_class_load()) { | |
779 Thread *thread = THREAD; | |
780 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); | |
781 JvmtiExport::post_class_load((JavaThread *) thread, k()); | |
782 } | |
783 } | |
784 } | |
785 if (HAS_PENDING_EXCEPTION || k.is_null()) { | |
786 // On error, clean up placeholders | |
787 { | |
788 MutexLocker mu(SystemDictionary_lock, THREAD); | |
789 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
790 SystemDictionary_lock->notify_all(); | |
791 } | |
792 return NULL; | |
793 } | |
794 } | |
795 } | |
796 | |
797 #ifdef ASSERT | |
798 { | |
799 Handle loader (THREAD, k->class_loader()); | |
800 MutexLocker mu(SystemDictionary_lock, THREAD); | |
801 oop kk = find_class_or_placeholder(name, loader); | |
802 assert(kk == k(), "should be present in dictionary"); | |
803 } | |
804 #endif | |
805 | |
806 // return if the protection domain in NULL | |
807 if (protection_domain() == NULL) return k(); | |
808 | |
809 // Check the protection domain has the right access | |
810 { | |
811 MutexLocker mu(SystemDictionary_lock, THREAD); | |
812 // Note that we have an entry, and entries can be deleted only during GC, | |
813 // so we cannot allow GC to occur while we're holding this entry. | |
814 // We're using a No_Safepoint_Verifier to catch any place where we | |
815 // might potentially do a GC at all. | |
816 // SystemDictionary::do_unloading() asserts that classes are only | |
817 // unloaded at a safepoint. | |
818 No_Safepoint_Verifier nosafepoint; | |
819 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, | |
820 class_loader, | |
821 protection_domain)) { | |
822 return k(); | |
823 } | |
824 } | |
825 | |
826 // Verify protection domain. If it fails an exception is thrown | |
827 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL))); | |
828 | |
829 return k(); | |
830 } | |
831 | |
832 | |
833 // This routine does not lock the system dictionary. | |
834 // | |
835 // Since readers don't hold a lock, we must make sure that system | |
836 // dictionary entries are only removed at a safepoint (when only one | |
837 // thread is running), and are added to in a safe way (all links must | |
838 // be updated in an MT-safe manner). | |
839 // | |
840 // Callers should be aware that an entry could be added just after | |
841 // _dictionary->bucket(index) is read here, so the caller will not see | |
842 // the new entry. | |
843 | |
844 klassOop SystemDictionary::find(symbolHandle class_name, | |
845 Handle class_loader, | |
846 Handle protection_domain, | |
847 TRAPS) { | |
848 | |
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849 // UseNewReflection |
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850 // The result of this call should be consistent with the result |
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851 // of the call to resolve_instance_class_or_null(). |
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852 // See evaluation 6790209 and 4474172 for more details. |
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853 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); |
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854 |
0 | 855 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); |
856 int d_index = dictionary()->hash_to_index(d_hash); | |
857 | |
858 { | |
859 // Note that we have an entry, and entries can be deleted only during GC, | |
860 // so we cannot allow GC to occur while we're holding this entry. | |
861 // We're using a No_Safepoint_Verifier to catch any place where we | |
862 // might potentially do a GC at all. | |
863 // SystemDictionary::do_unloading() asserts that classes are only | |
864 // unloaded at a safepoint. | |
865 No_Safepoint_Verifier nosafepoint; | |
866 return dictionary()->find(d_index, d_hash, class_name, class_loader, | |
867 protection_domain, THREAD); | |
868 } | |
869 } | |
870 | |
871 | |
872 // Look for a loaded instance or array klass by name. Do not do any loading. | |
873 // return NULL in case of error. | |
874 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name, | |
875 Handle class_loader, | |
876 Handle protection_domain, | |
877 TRAPS) { | |
878 klassOop k = NULL; | |
879 assert(class_name() != NULL, "class name must be non NULL"); | |
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880 |
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881 // Try to get one of the well-known klasses. |
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882 if (LinkWellKnownClasses) { |
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883 k = find_well_known_klass(class_name()); |
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884 if (k != NULL) { |
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885 return k; |
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886 } |
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887 } |
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888 |
0 | 889 if (FieldType::is_array(class_name())) { |
890 // The name refers to an array. Parse the name. | |
891 jint dimension; | |
892 symbolOop object_key; | |
893 | |
894 // dimension and object_key are assigned as a side-effect of this call | |
895 BasicType t = FieldType::get_array_info(class_name(), &dimension, | |
896 &object_key, CHECK_(NULL)); | |
897 if (t != T_OBJECT) { | |
898 k = Universe::typeArrayKlassObj(t); | |
899 } else { | |
900 symbolHandle h_key(THREAD, object_key); | |
901 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD); | |
902 } | |
903 if (k != NULL) { | |
904 k = Klass::cast(k)->array_klass_or_null(dimension); | |
905 } | |
906 } else { | |
907 k = find(class_name, class_loader, protection_domain, THREAD); | |
908 } | |
909 return k; | |
910 } | |
911 | |
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912 // Quick range check for names of well-known classes: |
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913 static symbolOop wk_klass_name_limits[2] = {NULL, NULL}; |
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914 |
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915 #ifndef PRODUCT |
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916 static int find_wkk_calls, find_wkk_probes, find_wkk_wins; |
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917 // counts for "hello world": 3983, 1616, 1075 |
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918 // => 60% hit after limit guard, 25% total win rate |
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919 #endif |
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920 |
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921 klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) { |
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922 // A bounds-check on class_name will quickly get a negative result. |
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923 NOT_PRODUCT(find_wkk_calls++); |
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924 if (class_name >= wk_klass_name_limits[0] && |
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925 class_name <= wk_klass_name_limits[1]) { |
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926 NOT_PRODUCT(find_wkk_probes++); |
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927 vmSymbols::SID sid = vmSymbols::find_sid(class_name); |
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928 if (sid != vmSymbols::NO_SID) { |
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929 klassOop k = NULL; |
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930 switch (sid) { |
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931 #define WK_KLASS_CASE(name, symbol, ignore_option) \ |
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932 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \ |
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933 k = WK_KLASS(name); break; |
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934 WK_KLASSES_DO(WK_KLASS_CASE) |
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935 #undef WK_KLASS_CASE |
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936 } |
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937 NOT_PRODUCT(if (k != NULL) find_wkk_wins++); |
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938 return k; |
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939 } |
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940 } |
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941 return NULL; |
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942 } |
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943 |
0 | 944 // Note: this method is much like resolve_from_stream, but |
945 // updates no supplemental data structures. | |
946 // TODO consolidate the two methods with a helper routine? | |
947 klassOop SystemDictionary::parse_stream(symbolHandle class_name, | |
948 Handle class_loader, | |
949 Handle protection_domain, | |
950 ClassFileStream* st, | |
431
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951 KlassHandle host_klass, |
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952 GrowableArray<Handle>* cp_patches, |
0 | 953 TRAPS) { |
954 symbolHandle parsed_name; | |
955 | |
956 // Parse the stream. Note that we do this even though this klass might | |
957 // already be present in the SystemDictionary, otherwise we would not | |
958 // throw potential ClassFormatErrors. | |
959 // | |
960 // Note: "name" is updated. | |
961 // Further note: a placeholder will be added for this class when | |
962 // super classes are loaded (resolve_super_or_fail). We expect this | |
963 // to be called for all classes but java.lang.Object; and we preload | |
964 // java.lang.Object through resolve_or_fail, not this path. | |
965 | |
966 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, | |
967 class_loader, | |
968 protection_domain, | |
969 parsed_name, | |
970 THREAD); | |
971 | |
514 | 972 |
0 | 973 // We don't redefine the class, so we just need to clean up whether there |
974 // was an error or not (don't want to modify any system dictionary | |
975 // data structures). | |
976 // Parsed name could be null if we threw an error before we got far | |
977 // enough along to parse it -- in that case, there is nothing to clean up. | |
978 if (!parsed_name.is_null()) { | |
979 unsigned int p_hash = placeholders()->compute_hash(parsed_name, | |
980 class_loader); | |
981 int p_index = placeholders()->hash_to_index(p_hash); | |
982 { | |
983 MutexLocker mu(SystemDictionary_lock, THREAD); | |
984 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); | |
985 SystemDictionary_lock->notify_all(); | |
986 } | |
987 } | |
988 | |
431
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989 if (host_klass.not_null() && k.not_null()) { |
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990 assert(AnonymousClasses, ""); |
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991 // If it's anonymous, initialize it now, since nobody else will. |
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992 k->set_host_klass(host_klass()); |
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993 |
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994 { |
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995 MutexLocker mu_r(Compile_lock, THREAD); |
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996 |
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997 // Add to class hierarchy, initialize vtables, and do possible |
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998 // deoptimizations. |
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999 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block |
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1000 |
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1001 // But, do not add to system dictionary. |
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1002 } |
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1003 |
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1004 k->eager_initialize(THREAD); |
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1005 |
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1006 // notify jvmti |
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1007 if (JvmtiExport::should_post_class_load()) { |
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1008 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); |
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1009 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); |
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1010 } |
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1011 } |
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1012 |
0 | 1013 return k(); |
1014 } | |
1015 | |
1016 // Add a klass to the system from a stream (called by jni_DefineClass and | |
1017 // JVM_DefineClass). | |
1018 // Note: class_name can be NULL. In that case we do not know the name of | |
1019 // the class until we have parsed the stream. | |
1020 | |
1021 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name, | |
1022 Handle class_loader, | |
1023 Handle protection_domain, | |
1024 ClassFileStream* st, | |
1025 TRAPS) { | |
1026 | |
514 | 1027 // Classloaders that support parallelism, e.g. bootstrap classloader, |
1028 // or all classloaders with UnsyncloadClass do not acquire lock here | |
1029 bool DoObjectLock = true; | |
1030 if (is_parallelCapable(class_loader)) { | |
1031 DoObjectLock = false; | |
1032 } | |
1033 | |
1034 // Make sure we are synchronized on the class loader before we proceed | |
0 | 1035 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); |
1036 check_loader_lock_contention(lockObject, THREAD); | |
514 | 1037 ObjectLocker ol(lockObject, THREAD, DoObjectLock); |
0 | 1038 |
1039 symbolHandle parsed_name; | |
1040 | |
1041 // Parse the stream. Note that we do this even though this klass might | |
1042 // already be present in the SystemDictionary, otherwise we would not | |
1043 // throw potential ClassFormatErrors. | |
1044 // | |
1045 // Note: "name" is updated. | |
1046 // Further note: a placeholder will be added for this class when | |
1047 // super classes are loaded (resolve_super_or_fail). We expect this | |
1048 // to be called for all classes but java.lang.Object; and we preload | |
1049 // java.lang.Object through resolve_or_fail, not this path. | |
1050 | |
1051 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, | |
1052 class_loader, | |
1053 protection_domain, | |
1054 parsed_name, | |
1055 THREAD); | |
1056 | |
1057 const char* pkg = "java/"; | |
1058 if (!HAS_PENDING_EXCEPTION && | |
1059 !class_loader.is_null() && | |
1060 !parsed_name.is_null() && | |
1061 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { | |
1062 // It is illegal to define classes in the "java." package from | |
1063 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader | |
1064 ResourceMark rm(THREAD); | |
1065 char* name = parsed_name->as_C_string(); | |
1066 char* index = strrchr(name, '/'); | |
1067 *index = '\0'; // chop to just the package name | |
1068 while ((index = strchr(name, '/')) != NULL) { | |
1069 *index = '.'; // replace '/' with '.' in package name | |
1070 } | |
1071 const char* fmt = "Prohibited package name: %s"; | |
1072 size_t len = strlen(fmt) + strlen(name); | |
1073 char* message = NEW_RESOURCE_ARRAY(char, len); | |
1074 jio_snprintf(message, len, fmt, name); | |
1075 Exceptions::_throw_msg(THREAD_AND_LOCATION, | |
1076 vmSymbols::java_lang_SecurityException(), message); | |
1077 } | |
1078 | |
1079 if (!HAS_PENDING_EXCEPTION) { | |
1080 assert(!parsed_name.is_null(), "Sanity"); | |
1081 assert(class_name.is_null() || class_name() == parsed_name(), | |
1082 "name mismatch"); | |
1083 // Verification prevents us from creating names with dots in them, this | |
1084 // asserts that that's the case. | |
1085 assert(is_internal_format(parsed_name), | |
1086 "external class name format used internally"); | |
1087 | |
1088 // Add class just loaded | |
514 | 1089 // If a class loader supports parallel classloading handle parallel define requests |
1090 // find_or_define_instance_class may return a different instanceKlass | |
1091 if (is_parallelCapable(class_loader)) { | |
1092 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); | |
1093 } else { | |
1094 define_instance_class(k, THREAD); | |
1095 } | |
0 | 1096 } |
1097 | |
1098 // If parsing the class file or define_instance_class failed, we | |
1099 // need to remove the placeholder added on our behalf. But we | |
1100 // must make sure parsed_name is valid first (it won't be if we had | |
1101 // a format error before the class was parsed far enough to | |
1102 // find the name). | |
1103 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) { | |
1104 unsigned int p_hash = placeholders()->compute_hash(parsed_name, | |
1105 class_loader); | |
1106 int p_index = placeholders()->hash_to_index(p_hash); | |
1107 { | |
1108 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1109 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); | |
1110 SystemDictionary_lock->notify_all(); | |
1111 } | |
1112 return NULL; | |
1113 } | |
1114 | |
1115 // Make sure that we didn't leave a place holder in the | |
1116 // SystemDictionary; this is only done on success | |
1117 debug_only( { | |
1118 if (!HAS_PENDING_EXCEPTION) { | |
1119 assert(!parsed_name.is_null(), "parsed_name is still null?"); | |
1120 symbolHandle h_name (THREAD, k->name()); | |
1121 Handle h_loader (THREAD, k->class_loader()); | |
1122 | |
1123 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1124 | |
1125 oop check = find_class_or_placeholder(parsed_name, class_loader); | |
1126 assert(check == k(), "should be present in the dictionary"); | |
1127 | |
1128 oop check2 = find_class_or_placeholder(h_name, h_loader); | |
1129 assert(check == check2, "name inconsistancy in SystemDictionary"); | |
1130 } | |
1131 } ); | |
1132 | |
1133 return k(); | |
1134 } | |
1135 | |
1136 | |
1137 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length, | |
1138 int number_of_entries) { | |
1139 assert(length == _nof_buckets * sizeof(HashtableBucket), | |
1140 "bad shared dictionary size."); | |
1141 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); | |
1142 } | |
1143 | |
1144 | |
1145 // If there is a shared dictionary, then find the entry for the | |
1146 // given shared system class, if any. | |
1147 | |
1148 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) { | |
1149 if (shared_dictionary() != NULL) { | |
1150 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle()); | |
1151 int d_index = dictionary()->hash_to_index(d_hash); | |
1152 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); | |
1153 } else { | |
1154 return NULL; | |
1155 } | |
1156 } | |
1157 | |
1158 | |
1159 // Load a class from the shared spaces (found through the shared system | |
1160 // dictionary). Force the superclass and all interfaces to be loaded. | |
1161 // Update the class definition to include sibling classes and no | |
1162 // subclasses (yet). [Classes in the shared space are not part of the | |
1163 // object hierarchy until loaded.] | |
1164 | |
1165 instanceKlassHandle SystemDictionary::load_shared_class( | |
1166 symbolHandle class_name, Handle class_loader, TRAPS) { | |
1167 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); | |
1168 return load_shared_class(ik, class_loader, THREAD); | |
1169 } | |
1170 | |
1171 // Note well! Changes to this method may affect oop access order | |
1172 // in the shared archive. Please take care to not make changes that | |
1173 // adversely affect cold start time by changing the oop access order | |
1174 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and | |
1175 // MarkAndMoveOrderedReadWrite closures. | |
1176 instanceKlassHandle SystemDictionary::load_shared_class( | |
1177 instanceKlassHandle ik, Handle class_loader, TRAPS) { | |
1178 assert(class_loader.is_null(), "non-null classloader for shared class?"); | |
1179 if (ik.not_null()) { | |
1180 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
1181 symbolHandle class_name(THREAD, ik->name()); | |
1182 | |
1183 // Found the class, now load the superclass and interfaces. If they | |
1184 // are shared, add them to the main system dictionary and reset | |
1185 // their hierarchy references (supers, subs, and interfaces). | |
1186 | |
1187 if (ik->super() != NULL) { | |
1188 symbolHandle cn(THREAD, ik->super()->klass_part()->name()); | |
1189 resolve_super_or_fail(class_name, cn, | |
1190 class_loader, Handle(), true, CHECK_(nh)); | |
1191 } | |
1192 | |
1193 objArrayHandle interfaces (THREAD, ik->local_interfaces()); | |
1194 int num_interfaces = interfaces->length(); | |
1195 for (int index = 0; index < num_interfaces; index++) { | |
1196 klassOop k = klassOop(interfaces->obj_at(index)); | |
1197 | |
1198 // Note: can not use instanceKlass::cast here because | |
1199 // interfaces' instanceKlass's C++ vtbls haven't been | |
1200 // reinitialized yet (they will be once the interface classes | |
1201 // are loaded) | |
1202 symbolHandle name (THREAD, k->klass_part()->name()); | |
1203 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); | |
1204 } | |
1205 | |
1206 // Adjust methods to recover missing data. They need addresses for | |
1207 // interpreter entry points and their default native method address | |
1208 // must be reset. | |
1209 | |
1210 // Updating methods must be done under a lock so multiple | |
1211 // threads don't update these in parallel | |
1212 // Shared classes are all currently loaded by the bootstrap | |
1213 // classloader, so this will never cause a deadlock on | |
1214 // a custom class loader lock. | |
1215 | |
1216 { | |
1217 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); | |
1218 check_loader_lock_contention(lockObject, THREAD); | |
1219 ObjectLocker ol(lockObject, THREAD, true); | |
1220 | |
1221 objArrayHandle methods (THREAD, ik->methods()); | |
1222 int num_methods = methods->length(); | |
1223 for (int index2 = 0; index2 < num_methods; ++index2) { | |
1224 methodHandle m(THREAD, methodOop(methods->obj_at(index2))); | |
1225 m()->link_method(m, CHECK_(nh)); | |
1226 } | |
1227 } | |
1228 | |
1229 if (TraceClassLoading) { | |
1230 ResourceMark rm; | |
1231 tty->print("[Loaded %s", ik->external_name()); | |
1232 tty->print(" from shared objects file"); | |
1233 tty->print_cr("]"); | |
1234 } | |
1235 // notify a class loaded from shared object | |
1236 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()), | |
1237 true /* shared class */); | |
1238 } | |
1239 return ik; | |
1240 } | |
1241 | |
1242 #ifdef KERNEL | |
1243 // Some classes on the bootstrap class path haven't been installed on the | |
1244 // system yet. Call the DownloadManager method to make them appear in the | |
1245 // bootstrap class path and try again to load the named class. | |
1246 // Note that with delegation class loaders all classes in another loader will | |
1247 // first try to call this so it'd better be fast!! | |
1248 static instanceKlassHandle download_and_retry_class_load( | |
1249 symbolHandle class_name, | |
1250 TRAPS) { | |
1251 | |
1252 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass(); | |
1253 instanceKlassHandle nk; | |
1254 | |
1255 // If download manager class isn't loaded just return. | |
1256 if (dlm == NULL) return nk; | |
1257 | |
1258 { HandleMark hm(THREAD); | |
1259 ResourceMark rm(THREAD); | |
1260 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk)); | |
1261 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk)); | |
1262 | |
1263 // return value | |
1264 JavaValue result(T_OBJECT); | |
1265 | |
1266 // Call the DownloadManager. We assume that it has a lock because | |
1267 // multiple classes could be not found and downloaded at the same time. | |
1268 // class sun.misc.DownloadManager; | |
1269 // public static String getBootClassPathEntryForClass(String className); | |
1270 JavaCalls::call_static(&result, | |
1271 KlassHandle(THREAD, dlm), | |
1272 vmSymbolHandles::getBootClassPathEntryForClass_name(), | |
1273 vmSymbolHandles::string_string_signature(), | |
1274 class_string, | |
1275 CHECK_(nk)); | |
1276 | |
1277 // Get result.string and add to bootclasspath | |
1278 assert(result.get_type() == T_OBJECT, "just checking"); | |
1279 oop obj = (oop) result.get_jobject(); | |
1280 if (obj == NULL) { return nk; } | |
1281 | |
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1282 Handle h_obj(THREAD, obj); |
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1283 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj, |
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1284 CHECK_(nk)); |
0 | 1285 |
1286 // lock the loader | |
1287 // we use this lock because JVMTI does. | |
1288 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock()); | |
1289 | |
1290 ObjectLocker ol(loader_lock, THREAD); | |
1291 // add the file to the bootclasspath | |
1292 ClassLoader::update_class_path_entry_list(new_class_name, true); | |
1293 } // end HandleMark | |
1294 | |
1295 if (TraceClassLoading) { | |
1296 ClassLoader::print_bootclasspath(); | |
1297 } | |
1298 return ClassLoader::load_classfile(class_name, CHECK_(nk)); | |
1299 } | |
1300 #endif // KERNEL | |
1301 | |
1302 | |
1303 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) { | |
1304 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
1305 if (class_loader.is_null()) { | |
1306 // Search the shared system dictionary for classes preloaded into the | |
1307 // shared spaces. | |
1308 instanceKlassHandle k; | |
1309 k = load_shared_class(class_name, class_loader, THREAD); | |
1310 | |
1311 if (k.is_null()) { | |
1312 // Use VM class loader | |
1313 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); | |
1314 } | |
1315 | |
1316 #ifdef KERNEL | |
1317 // If the VM class loader has failed to load the class, call the | |
1318 // DownloadManager class to make it magically appear on the classpath | |
1319 // and try again. This is only configured with the Kernel VM. | |
1320 if (k.is_null()) { | |
1321 k = download_and_retry_class_load(class_name, CHECK_(nh)); | |
1322 } | |
1323 #endif // KERNEL | |
1324 | |
514 | 1325 // find_or_define_instance_class may return a different instanceKlass |
0 | 1326 if (!k.is_null()) { |
1327 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); | |
1328 } | |
1329 return k; | |
1330 } else { | |
1331 // Use user specified class loader to load class. Call loadClass operation on class_loader. | |
1332 ResourceMark rm(THREAD); | |
1333 | |
1334 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); | |
1335 // Translate to external class name format, i.e., convert '/' chars to '.' | |
1336 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); | |
1337 | |
1338 JavaValue result(T_OBJECT); | |
1339 | |
1340 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass()); | |
1341 | |
514 | 1342 // Call public unsynchronized loadClass(String) directly for all class loaders |
1343 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will | |
1344 // acquire a class-name based lock rather than the class loader object lock. | |
1345 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), | |
1346 // so the call to loadClassInternal() was not required. | |
1347 // | |
1348 // UnsyncloadClass flag means both call loadClass(String) and do | |
1349 // not acquire the class loader lock even for class loaders that are | |
1350 // not parallelCapable. This was a risky transitional | |
1351 // flag for diagnostic purposes only. It is risky to call | |
0 | 1352 // custom class loaders without synchronization. |
1353 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of | |
514 | 1354 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. |
0 | 1355 // Do NOT assume this will be supported in future releases. |
514 | 1356 // |
1357 // Added MustCallLoadClassInternal in case we discover in the field | |
1358 // a customer that counts on this call | |
1359 if (MustCallLoadClassInternal && has_loadClassInternal()) { | |
0 | 1360 JavaCalls::call_special(&result, |
1361 class_loader, | |
1362 spec_klass, | |
1363 vmSymbolHandles::loadClassInternal_name(), | |
1364 vmSymbolHandles::string_class_signature(), | |
1365 string, | |
1366 CHECK_(nh)); | |
1367 } else { | |
1368 JavaCalls::call_virtual(&result, | |
1369 class_loader, | |
1370 spec_klass, | |
1371 vmSymbolHandles::loadClass_name(), | |
1372 vmSymbolHandles::string_class_signature(), | |
1373 string, | |
1374 CHECK_(nh)); | |
1375 } | |
1376 | |
1377 assert(result.get_type() == T_OBJECT, "just checking"); | |
1378 oop obj = (oop) result.get_jobject(); | |
1379 | |
1380 // Primitive classes return null since forName() can not be | |
1381 // used to obtain any of the Class objects representing primitives or void | |
1382 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { | |
1383 instanceKlassHandle k = | |
1384 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj)); | |
1385 // For user defined Java class loaders, check that the name returned is | |
1386 // the same as that requested. This check is done for the bootstrap | |
1387 // loader when parsing the class file. | |
1388 if (class_name() == k->name()) { | |
1389 return k; | |
1390 } | |
1391 } | |
1392 // Class is not found or has the wrong name, return NULL | |
1393 return nh; | |
1394 } | |
1395 } | |
1396 | |
1397 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { | |
1398 | |
1399 Handle class_loader_h(THREAD, k->class_loader()); | |
1400 | |
514 | 1401 // for bootstrap and other parallel classloaders don't acquire lock, |
1402 // use placeholder token | |
1403 // If a parallelCapable class loader calls define_instance_class instead of | |
1404 // find_or_define_instance_class to get here, we have a timing | |
1405 // hole with systemDictionary updates and check_constraints | |
1406 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { | |
0 | 1407 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, |
1408 compute_loader_lock_object(class_loader_h, THREAD)), | |
1409 "define called without lock"); | |
1410 } | |
1411 | |
1412 // Check class-loading constraints. Throw exception if violation is detected. | |
1413 // Grabs and releases SystemDictionary_lock | |
1414 // The check_constraints/find_class call and update_dictionary sequence | |
1415 // must be "atomic" for a specific class/classloader pair so we never | |
1416 // define two different instanceKlasses for that class/classloader pair. | |
1417 // Existing classloaders will call define_instance_class with the | |
1418 // classloader lock held | |
1419 // Parallel classloaders will call find_or_define_instance_class | |
1420 // which will require a token to perform the define class | |
1421 symbolHandle name_h(THREAD, k->name()); | |
1422 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h); | |
1423 int d_index = dictionary()->hash_to_index(d_hash); | |
1424 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); | |
1425 | |
1426 // Register class just loaded with class loader (placed in Vector) | |
1427 // Note we do this before updating the dictionary, as this can | |
1428 // fail with an OutOfMemoryError (if it does, we will *not* put this | |
1429 // class in the dictionary and will not update the class hierarchy). | |
1430 if (k->class_loader() != NULL) { | |
1431 methodHandle m(THREAD, Universe::loader_addClass_method()); | |
1432 JavaValue result(T_VOID); | |
1433 JavaCallArguments args(class_loader_h); | |
1434 args.push_oop(Handle(THREAD, k->java_mirror())); | |
1435 JavaCalls::call(&result, m, &args, CHECK); | |
1436 } | |
1437 | |
1438 // Add the new class. We need recompile lock during update of CHA. | |
1439 { | |
1440 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h); | |
1441 int p_index = placeholders()->hash_to_index(p_hash); | |
1442 | |
1443 MutexLocker mu_r(Compile_lock, THREAD); | |
1444 | |
1445 // Add to class hierarchy, initialize vtables, and do possible | |
1446 // deoptimizations. | |
1447 add_to_hierarchy(k, CHECK); // No exception, but can block | |
1448 | |
1449 // Add to systemDictionary - so other classes can see it. | |
1450 // Grabs and releases SystemDictionary_lock | |
1451 update_dictionary(d_index, d_hash, p_index, p_hash, | |
1452 k, class_loader_h, THREAD); | |
1453 } | |
1454 k->eager_initialize(THREAD); | |
1455 | |
1456 // notify jvmti | |
1457 if (JvmtiExport::should_post_class_load()) { | |
1458 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); | |
1459 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); | |
1460 | |
1461 } | |
1462 } | |
1463 | |
1464 // Support parallel classloading | |
1465 // Initial implementation for bootstrap classloader | |
1466 // For custom class loaders that support parallel classloading, | |
514 | 1467 // With AllowParallelDefine flag==true, in case they do not synchronize around |
1468 // FindLoadedClass/DefineClass, calls, we check for parallel | |
0 | 1469 // loading for them, wait if a defineClass is in progress |
1470 // and return the initial requestor's results | |
514 | 1471 // With AllowParallelDefine flag==false, call through to define_instance_class |
1472 // which will throw LinkageError: duplicate class definition. | |
0 | 1473 // For better performance, the class loaders should synchronize |
514 | 1474 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they |
0 | 1475 // potentially waste time reading and parsing the bytestream. |
1476 // Note: VM callers should ensure consistency of k/class_name,class_loader | |
1477 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { | |
1478 | |
1479 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
515 | 1480 symbolHandle name_h(THREAD, k->name()); // passed in class_name may be null |
0 | 1481 |
515 | 1482 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader); |
0 | 1483 int d_index = dictionary()->hash_to_index(d_hash); |
1484 | |
1485 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS | |
515 | 1486 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader); |
0 | 1487 int p_index = placeholders()->hash_to_index(p_hash); |
1488 PlaceholderEntry* probe; | |
1489 | |
1490 { | |
1491 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1492 // First check if class already defined | |
515 | 1493 klassOop check = find_class(d_index, d_hash, name_h, class_loader); |
0 | 1494 if (check != NULL) { |
1495 return(instanceKlassHandle(THREAD, check)); | |
1496 } | |
1497 | |
1498 // Acquire define token for this class/classloader | |
1499 symbolHandle nullsymbolHandle; | |
515 | 1500 probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD); |
514 | 1501 // Wait if another thread defining in parallel |
1502 // All threads wait - even those that will throw duplicate class: otherwise | |
1503 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails | |
1504 // if other thread has not finished updating dictionary | |
1505 while (probe->definer() != NULL) { | |
1506 SystemDictionary_lock->wait(); | |
1507 } | |
1508 // Only special cases allow parallel defines and can use other thread's results | |
1509 // Other cases fall through, and may run into duplicate defines | |
1510 // caught by finding an entry in the SystemDictionary | |
1511 if ((UnsyncloadClass || AllowParallelDefineClass) && (probe->instanceKlass() != NULL)) { | |
0 | 1512 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); |
515 | 1513 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); |
514 | 1514 SystemDictionary_lock->notify_all(); |
0 | 1515 #ifdef ASSERT |
515 | 1516 klassOop check = find_class(d_index, d_hash, name_h, class_loader); |
514 | 1517 assert(check != NULL, "definer missed recording success"); |
0 | 1518 #endif |
514 | 1519 return(instanceKlassHandle(THREAD, probe->instanceKlass())); |
0 | 1520 } else { |
514 | 1521 // This thread will define the class (even if earlier thread tried and had an error) |
1522 probe->set_definer(THREAD); | |
0 | 1523 } |
1524 } | |
1525 | |
1526 define_instance_class(k, THREAD); | |
1527 | |
1528 Handle linkage_exception = Handle(); // null handle | |
1529 | |
1530 // definer must notify any waiting threads | |
1531 { | |
1532 MutexLocker mu(SystemDictionary_lock, THREAD); | |
515 | 1533 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader); |
0 | 1534 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); |
1535 if (probe != NULL) { | |
1536 if (HAS_PENDING_EXCEPTION) { | |
1537 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); | |
1538 CLEAR_PENDING_EXCEPTION; | |
1539 } else { | |
1540 probe->set_instanceKlass(k()); | |
1541 } | |
1542 probe->set_definer(NULL); | |
1543 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); | |
515 | 1544 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); |
0 | 1545 SystemDictionary_lock->notify_all(); |
1546 } | |
1547 } | |
1548 | |
1549 // Can't throw exception while holding lock due to rank ordering | |
1550 if (linkage_exception() != NULL) { | |
1551 THROW_OOP_(linkage_exception(), nh); // throws exception and returns | |
1552 } | |
1553 | |
1554 return k; | |
1555 } | |
1556 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { | |
1557 // If class_loader is NULL we synchronize on _system_loader_lock_obj | |
1558 if (class_loader.is_null()) { | |
1559 return Handle(THREAD, _system_loader_lock_obj); | |
1560 } else { | |
1561 return class_loader; | |
1562 } | |
1563 } | |
1564 | |
1565 // This method is added to check how often we have to wait to grab loader | |
1566 // lock. The results are being recorded in the performance counters defined in | |
1567 // ClassLoader::_sync_systemLoaderLockContentionRate and | |
1568 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. | |
1569 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { | |
1570 if (!UsePerfData) { | |
1571 return; | |
1572 } | |
1573 | |
1574 assert(!loader_lock.is_null(), "NULL lock object"); | |
1575 | |
1576 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) | |
1577 == ObjectSynchronizer::owner_other) { | |
1578 // contention will likely happen, so increment the corresponding | |
1579 // contention counter. | |
1580 if (loader_lock() == _system_loader_lock_obj) { | |
1581 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); | |
1582 } else { | |
1583 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); | |
1584 } | |
1585 } | |
1586 } | |
1587 | |
1588 // ---------------------------------------------------------------------------- | |
1589 // Lookup | |
1590 | |
1591 klassOop SystemDictionary::find_class(int index, unsigned int hash, | |
1592 symbolHandle class_name, | |
1593 Handle class_loader) { | |
1594 assert_locked_or_safepoint(SystemDictionary_lock); | |
1595 assert (index == dictionary()->index_for(class_name, class_loader), | |
1596 "incorrect index?"); | |
1597 | |
1598 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader); | |
1599 return k; | |
1600 } | |
1601 | |
1602 | |
1603 // Basic find on classes in the midst of being loaded | |
1604 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash, | |
1605 symbolHandle class_name, | |
1606 Handle class_loader) { | |
1607 assert_locked_or_safepoint(SystemDictionary_lock); | |
1608 | |
1609 return placeholders()->find_entry(index, hash, class_name, class_loader); | |
1610 } | |
1611 | |
1612 | |
1613 // Used for assertions and verification only | |
1614 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name, | |
1615 Handle class_loader) { | |
1616 #ifndef ASSERT | |
1617 guarantee(VerifyBeforeGC || | |
1618 VerifyDuringGC || | |
1619 VerifyBeforeExit || | |
1620 VerifyAfterGC, "too expensive"); | |
1621 #endif | |
1622 assert_locked_or_safepoint(SystemDictionary_lock); | |
1623 symbolOop class_name_ = class_name(); | |
1624 oop class_loader_ = class_loader(); | |
1625 | |
1626 // First look in the loaded class array | |
1627 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); | |
1628 int d_index = dictionary()->hash_to_index(d_hash); | |
1629 oop lookup = find_class(d_index, d_hash, class_name, class_loader); | |
1630 | |
1631 if (lookup == NULL) { | |
1632 // Next try the placeholders | |
1633 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader); | |
1634 int p_index = placeholders()->hash_to_index(p_hash); | |
1635 lookup = find_placeholder(p_index, p_hash, class_name, class_loader); | |
1636 } | |
1637 | |
1638 return lookup; | |
1639 } | |
1640 | |
1641 | |
1642 // Get the next class in the diictionary. | |
1643 klassOop SystemDictionary::try_get_next_class() { | |
1644 return dictionary()->try_get_next_class(); | |
1645 } | |
1646 | |
1647 | |
1648 // ---------------------------------------------------------------------------- | |
1649 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock | |
1650 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in | |
1651 // before a new class is used. | |
1652 | |
1653 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { | |
1654 assert(k.not_null(), "just checking"); | |
1655 // Link into hierachy. Make sure the vtables are initialized before linking into | |
1656 k->append_to_sibling_list(); // add to superklass/sibling list | |
1657 k->process_interfaces(THREAD); // handle all "implements" declarations | |
1658 k->set_init_state(instanceKlass::loaded); | |
1659 // Now flush all code that depended on old class hierarchy. | |
1660 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) | |
1661 // Also, first reinitialize vtable because it may have gotten out of synch | |
1662 // while the new class wasn't connected to the class hierarchy. | |
1663 Universe::flush_dependents_on(k); | |
1664 } | |
1665 | |
1666 | |
1667 // ---------------------------------------------------------------------------- | |
1668 // GC support | |
1669 | |
1670 // Following roots during mark-sweep is separated in two phases. | |
1671 // | |
1672 // The first phase follows preloaded classes and all other system | |
1673 // classes, since these will never get unloaded anyway. | |
1674 // | |
1675 // The second phase removes (unloads) unreachable classes from the | |
1676 // system dictionary and follows the remaining classes' contents. | |
1677 | |
1678 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { | |
1679 // Follow preloaded classes/mirrors and system loader object | |
1680 blk->do_oop(&_java_system_loader); | |
1681 preloaded_oops_do(blk); | |
1682 always_strong_classes_do(blk); | |
1683 } | |
1684 | |
1685 | |
1686 void SystemDictionary::always_strong_classes_do(OopClosure* blk) { | |
1687 // Follow all system classes and temporary placeholders in dictionary | |
1688 dictionary()->always_strong_classes_do(blk); | |
1689 | |
1690 // Placeholders. These are *always* strong roots, as they | |
1691 // represent classes we're actively loading. | |
1692 placeholders_do(blk); | |
1693 | |
1694 // Loader constraints. We must keep the symbolOop used in the name alive. | |
1695 constraints()->always_strong_classes_do(blk); | |
1696 | |
1697 // Resolution errors keep the symbolOop for the error alive | |
1698 resolution_errors()->always_strong_classes_do(blk); | |
1699 } | |
1700 | |
1701 | |
1702 void SystemDictionary::placeholders_do(OopClosure* blk) { | |
1703 placeholders()->oops_do(blk); | |
1704 } | |
1705 | |
1706 | |
1707 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { | |
1708 bool result = dictionary()->do_unloading(is_alive); | |
1709 constraints()->purge_loader_constraints(is_alive); | |
1710 resolution_errors()->purge_resolution_errors(is_alive); | |
1711 return result; | |
1712 } | |
1713 | |
1714 | |
1715 // The mirrors are scanned by shared_oops_do() which is | |
1716 // not called by oops_do(). In order to process oops in | |
1717 // a necessary order, shared_oops_do() is call by | |
1718 // Universe::oops_do(). | |
1719 void SystemDictionary::oops_do(OopClosure* f) { | |
1720 // Adjust preloaded classes and system loader object | |
1721 f->do_oop(&_java_system_loader); | |
1722 preloaded_oops_do(f); | |
1723 | |
1724 lazily_loaded_oops_do(f); | |
1725 | |
1726 // Adjust dictionary | |
1727 dictionary()->oops_do(f); | |
1728 | |
1729 // Partially loaded classes | |
1730 placeholders()->oops_do(f); | |
1731 | |
1732 // Adjust constraint table | |
1733 constraints()->oops_do(f); | |
1734 | |
1735 // Adjust resolution error table | |
1736 resolution_errors()->oops_do(f); | |
1737 } | |
1738 | |
1739 | |
1740 void SystemDictionary::preloaded_oops_do(OopClosure* f) { | |
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1741 f->do_oop((oop*) &wk_klass_name_limits[0]); |
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1742 f->do_oop((oop*) &wk_klass_name_limits[1]); |
0 | 1743 |
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1744 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { |
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1745 f->do_oop((oop*) &_well_known_klasses[k]); |
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1746 } |
0 | 1747 |
1748 { | |
1749 for (int i = 0; i < T_VOID+1; i++) { | |
1750 if (_box_klasses[i] != NULL) { | |
1751 assert(i >= T_BOOLEAN, "checking"); | |
1752 f->do_oop((oop*) &_box_klasses[i]); | |
1753 } | |
1754 } | |
1755 } | |
1756 | |
1757 // The basic type mirrors would have already been processed in | |
1758 // Universe::oops_do(), via a call to shared_oops_do(), so should | |
1759 // not be processed again. | |
1760 | |
1761 f->do_oop((oop*) &_system_loader_lock_obj); | |
1762 FilteredFieldsMap::klasses_oops_do(f); | |
1763 } | |
1764 | |
1765 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) { | |
1766 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass); | |
1767 } | |
1768 | |
1769 // Just the classes from defining class loaders | |
1770 // Don't iterate over placeholders | |
1771 void SystemDictionary::classes_do(void f(klassOop)) { | |
1772 dictionary()->classes_do(f); | |
1773 } | |
1774 | |
1775 // Added for initialize_itable_for_klass | |
1776 // Just the classes from defining class loaders | |
1777 // Don't iterate over placeholders | |
1778 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) { | |
1779 dictionary()->classes_do(f, CHECK); | |
1780 } | |
1781 | |
1782 // All classes, and their class loaders | |
1783 // Don't iterate over placeholders | |
1784 void SystemDictionary::classes_do(void f(klassOop, oop)) { | |
1785 dictionary()->classes_do(f); | |
1786 } | |
1787 | |
1788 // All classes, and their class loaders | |
1789 // (added for helpers that use HandleMarks and ResourceMarks) | |
1790 // Don't iterate over placeholders | |
1791 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) { | |
1792 dictionary()->classes_do(f, CHECK); | |
1793 } | |
1794 | |
1795 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) { | |
1796 placeholders()->entries_do(f); | |
1797 } | |
1798 | |
1799 void SystemDictionary::methods_do(void f(methodOop)) { | |
1800 dictionary()->methods_do(f); | |
1801 } | |
1802 | |
1803 // ---------------------------------------------------------------------------- | |
1804 // Lazily load klasses | |
1805 | |
1806 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { | |
1807 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); | |
1808 | |
1809 // if multiple threads calling this function, only one thread will load | |
1810 // the class. The other threads will find the loaded version once the | |
1811 // class is loaded. | |
1812 klassOop aos = _abstract_ownable_synchronizer_klass; | |
1813 if (aos == NULL) { | |
1814 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); | |
1815 // Force a fence to prevent any read before the write completes | |
1816 OrderAccess::fence(); | |
1817 _abstract_ownable_synchronizer_klass = k; | |
1818 } | |
1819 } | |
1820 | |
1821 // ---------------------------------------------------------------------------- | |
1822 // Initialization | |
1823 | |
1824 void SystemDictionary::initialize(TRAPS) { | |
1825 // Allocate arrays | |
1826 assert(dictionary() == NULL, | |
1827 "SystemDictionary should only be initialized once"); | |
1828 _dictionary = new Dictionary(_nof_buckets); | |
1829 _placeholders = new PlaceholderTable(_nof_buckets); | |
1830 _number_of_modifications = 0; | |
1831 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); | |
1832 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); | |
1833 | |
1834 // Allocate private object used as system class loader lock | |
1835 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK); | |
1836 // Initialize basic classes | |
1837 initialize_preloaded_classes(CHECK); | |
1838 } | |
1839 | |
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1840 // Compact table of directions on the initialization of klasses: |
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1841 static const short wk_init_info[] = { |
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1842 #define WK_KLASS_INIT_INFO(name, symbol, option) \ |
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1843 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ |
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1844 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ |
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1845 | (int)SystemDictionary::option ), |
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1846 WK_KLASSES_DO(WK_KLASS_INIT_INFO) |
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1847 #undef WK_KLASS_INIT_INFO |
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1848 0 |
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1849 }; |
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1850 |
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1851 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { |
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1852 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); |
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1853 int info = wk_init_info[id - FIRST_WKID]; |
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1854 int sid = (info >> CEIL_LG_OPTION_LIMIT); |
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1855 symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid); |
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1856 klassOop* klassp = &_well_known_klasses[id]; |
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1857 bool must_load = (init_opt < SystemDictionary::Opt); |
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1858 bool try_load = true; |
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1859 if (init_opt == SystemDictionary::Opt_Kernel) { |
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1860 #ifndef KERNEL |
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1861 try_load = false; |
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1862 #endif //KERNEL |
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1863 } |
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1864 if ((*klassp) == NULL && try_load) { |
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1865 if (must_load) { |
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1866 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class |
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1867 } else { |
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1868 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass |
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1869 } |
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1870 } |
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1871 return ((*klassp) != NULL); |
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1872 } |
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1873 |
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1874 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { |
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1875 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); |
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1876 for (int id = (int)start_id; id < (int)limit_id; id++) { |
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1877 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); |
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1878 int info = wk_init_info[id - FIRST_WKID]; |
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1879 int sid = (info >> CEIL_LG_OPTION_LIMIT); |
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1880 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); |
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1881 |
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1882 initialize_wk_klass((WKID)id, opt, CHECK); |
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1883 |
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1884 // Update limits, so find_well_known_klass can be very fast: |
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1885 symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid); |
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1886 if (wk_klass_name_limits[1] == NULL) { |
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1887 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s; |
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1888 } else if (wk_klass_name_limits[1] < s) { |
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1889 wk_klass_name_limits[1] = s; |
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1890 } else if (wk_klass_name_limits[0] > s) { |
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1891 wk_klass_name_limits[0] = s; |
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1892 } |
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1893 } |
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1894 } |
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1895 |
0 | 1896 |
1897 void SystemDictionary::initialize_preloaded_classes(TRAPS) { | |
132
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1898 assert(WK_KLASS(object_klass) == NULL, "preloaded classes should only be initialized once"); |
0 | 1899 // Preload commonly used klasses |
132
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1900 WKID scan = FIRST_WKID; |
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1901 // first do Object, String, Class |
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1902 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(class_klass), scan, CHECK); |
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1903 |
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1904 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(class_klass))); |
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1905 |
0 | 1906 // Fixup mirrors for classes loaded before java.lang.Class. |
1907 // These calls iterate over the objects currently in the perm gen | |
1908 // so calling them at this point is matters (not before when there | |
1909 // are fewer objects and not later after there are more objects | |
1910 // in the perm gen. | |
1911 Universe::initialize_basic_type_mirrors(CHECK); | |
1912 Universe::fixup_mirrors(CHECK); | |
1913 | |
132
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1914 // do a bunch more: |
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1915 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(reference_klass), scan, CHECK); |
0 | 1916 |
1917 // Preload ref klasses and set reference types | |
132
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1918 instanceKlass::cast(WK_KLASS(reference_klass))->set_reference_type(REF_OTHER); |
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1919 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(reference_klass)); |
0 | 1920 |
132
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1921 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(phantom_reference_klass), scan, CHECK); |
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1922 instanceKlass::cast(WK_KLASS(soft_reference_klass))->set_reference_type(REF_SOFT); |
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1923 instanceKlass::cast(WK_KLASS(weak_reference_klass))->set_reference_type(REF_WEAK); |
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1924 instanceKlass::cast(WK_KLASS(final_reference_klass))->set_reference_type(REF_FINAL); |
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1925 instanceKlass::cast(WK_KLASS(phantom_reference_klass))->set_reference_type(REF_PHANTOM); |
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1926 |
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1927 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); |
0 | 1928 |
132
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1929 _box_klasses[T_BOOLEAN] = WK_KLASS(boolean_klass); |
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1930 _box_klasses[T_CHAR] = WK_KLASS(char_klass); |
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1931 _box_klasses[T_FLOAT] = WK_KLASS(float_klass); |
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1932 _box_klasses[T_DOUBLE] = WK_KLASS(double_klass); |
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1933 _box_klasses[T_BYTE] = WK_KLASS(byte_klass); |
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1934 _box_klasses[T_SHORT] = WK_KLASS(short_klass); |
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1935 _box_klasses[T_INT] = WK_KLASS(int_klass); |
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1936 _box_klasses[T_LONG] = WK_KLASS(long_klass); |
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1937 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); |
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1938 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); |
0 | 1939 |
1940 #ifdef KERNEL | |
132
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1941 if (sun_jkernel_DownloadManager_klass() == NULL) { |
0 | 1942 warning("Cannot find sun/jkernel/DownloadManager"); |
1943 } | |
1944 #endif // KERNEL | |
514 | 1945 |
0 | 1946 { // Compute whether we should use loadClass or loadClassInternal when loading classes. |
1947 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); | |
1948 _has_loadClassInternal = (method != NULL); | |
1949 } | |
1950 { // Compute whether we should use checkPackageAccess or NOT | |
1951 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); | |
1952 _has_checkPackageAccess = (method != NULL); | |
1953 } | |
1954 } | |
1955 | |
1956 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). | |
1957 // If so, returns the basic type it holds. If not, returns T_OBJECT. | |
1958 BasicType SystemDictionary::box_klass_type(klassOop k) { | |
1959 assert(k != NULL, ""); | |
1960 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { | |
1961 if (_box_klasses[i] == k) | |
1962 return (BasicType)i; | |
1963 } | |
1964 return T_OBJECT; | |
1965 } | |
1966 | |
1967 // Constraints on class loaders. The details of the algorithm can be | |
1968 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java | |
1969 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is | |
1970 // that the system dictionary needs to maintain a set of contraints that | |
1971 // must be satisfied by all classes in the dictionary. | |
1972 // if defining is true, then LinkageError if already in systemDictionary | |
1973 // if initiating loader, then ok if instanceKlass matches existing entry | |
1974 | |
1975 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, | |
1976 instanceKlassHandle k, | |
1977 Handle class_loader, bool defining, | |
1978 TRAPS) { | |
1979 const char *linkage_error = NULL; | |
1980 { | |
1981 symbolHandle name (THREAD, k->name()); | |
1982 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1983 | |
1984 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
1985 if (check != (klassOop)NULL) { | |
1986 // if different instanceKlass - duplicate class definition, | |
1987 // else - ok, class loaded by a different thread in parallel, | |
1988 // we should only have found it if it was done loading and ok to use | |
1989 // system dictionary only holds instance classes, placeholders | |
1990 // also holds array classes | |
1991 | |
1992 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary"); | |
1993 if ((defining == true) || (k() != check)) { | |
1994 linkage_error = "loader (instance of %s): attempted duplicate class " | |
1995 "definition for name: \"%s\""; | |
1996 } else { | |
1997 return; | |
1998 } | |
1999 } | |
2000 | |
2001 #ifdef ASSERT | |
2002 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); | |
2003 int p_index = placeholders()->hash_to_index(p_hash); | |
2004 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); | |
2005 assert(ph_check == NULL || ph_check == name(), "invalid symbol"); | |
2006 #endif | |
2007 | |
2008 if (linkage_error == NULL) { | |
2009 if (constraints()->check_or_update(k, class_loader, name) == false) { | |
2010 linkage_error = "loader constraint violation: loader (instance of %s)" | |
2011 " previously initiated loading for a different type with name \"%s\""; | |
2012 } | |
2013 } | |
2014 } | |
2015 | |
2016 // Throw error now if needed (cannot throw while holding | |
2017 // SystemDictionary_lock because of rank ordering) | |
2018 | |
2019 if (linkage_error) { | |
2020 ResourceMark rm(THREAD); | |
2021 const char* class_loader_name = loader_name(class_loader()); | |
2022 char* type_name = k->name()->as_C_string(); | |
2023 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + | |
2024 strlen(type_name); | |
2025 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); | |
2026 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); | |
2027 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); | |
2028 } | |
2029 } | |
2030 | |
2031 | |
2032 // Update system dictionary - done after check_constraint and add_to_hierachy | |
2033 // have been called. | |
2034 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, | |
2035 int p_index, unsigned int p_hash, | |
2036 instanceKlassHandle k, | |
2037 Handle class_loader, | |
2038 TRAPS) { | |
2039 // Compile_lock prevents systemDictionary updates during compilations | |
2040 assert_locked_or_safepoint(Compile_lock); | |
2041 symbolHandle name (THREAD, k->name()); | |
2042 | |
2043 { | |
2044 MutexLocker mu1(SystemDictionary_lock, THREAD); | |
2045 | |
2046 // See whether biased locking is enabled and if so set it for this | |
2047 // klass. | |
2048 // Note that this must be done past the last potential blocking | |
2049 // point / safepoint. We enable biased locking lazily using a | |
2050 // VM_Operation to iterate the SystemDictionary and installing the | |
2051 // biasable mark word into each instanceKlass's prototype header. | |
2052 // To avoid race conditions where we accidentally miss enabling the | |
2053 // optimization for one class in the process of being added to the | |
2054 // dictionary, we must not safepoint after the test of | |
2055 // BiasedLocking::enabled(). | |
2056 if (UseBiasedLocking && BiasedLocking::enabled()) { | |
2057 // Set biased locking bit for all loaded classes; it will be | |
2058 // cleared if revocation occurs too often for this type | |
2059 // NOTE that we must only do this when the class is initally | |
2060 // defined, not each time it is referenced from a new class loader | |
2061 if (k->class_loader() == class_loader()) { | |
2062 k->set_prototype_header(markOopDesc::biased_locking_prototype()); | |
2063 } | |
2064 } | |
2065 | |
2066 // Check for a placeholder. If there, remove it and make a | |
2067 // new system dictionary entry. | |
2068 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
2069 klassOop sd_check = find_class(d_index, d_hash, name, class_loader); | |
2070 if (sd_check == NULL) { | |
2071 dictionary()->add_klass(name, class_loader, k); | |
2072 notice_modification(); | |
2073 } | |
2074 #ifdef ASSERT | |
2075 sd_check = find_class(d_index, d_hash, name, class_loader); | |
2076 assert (sd_check != NULL, "should have entry in system dictionary"); | |
2077 // Changed to allow PH to remain to complete class circularity checking | |
2078 // while only one thread can define a class at one time, multiple | |
2079 // classes can resolve the superclass for a class at one time, | |
2080 // and the placeholder is used to track that | |
2081 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); | |
2082 // assert (ph_check == NULL, "should not have a placeholder entry"); | |
2083 #endif | |
2084 SystemDictionary_lock->notify_all(); | |
2085 } | |
2086 } | |
2087 | |
2088 | |
2089 klassOop SystemDictionary::find_constrained_instance_or_array_klass( | |
2090 symbolHandle class_name, Handle class_loader, TRAPS) { | |
2091 | |
2092 // First see if it has been loaded directly. | |
2093 // Force the protection domain to be null. (This removes protection checks.) | |
2094 Handle no_protection_domain; | |
2095 klassOop klass = find_instance_or_array_klass(class_name, class_loader, | |
2096 no_protection_domain, CHECK_NULL); | |
2097 if (klass != NULL) | |
2098 return klass; | |
2099 | |
2100 // Now look to see if it has been loaded elsewhere, and is subject to | |
2101 // a loader constraint that would require this loader to return the | |
2102 // klass that is already loaded. | |
2103 if (FieldType::is_array(class_name())) { | |
2104 // Array classes are hard because their klassOops are not kept in the | |
2105 // constraint table. The array klass may be constrained, but the elem class | |
2106 // may not be. | |
2107 jint dimension; | |
2108 symbolOop object_key; | |
2109 BasicType t = FieldType::get_array_info(class_name(), &dimension, | |
2110 &object_key, CHECK_(NULL)); | |
2111 if (t != T_OBJECT) { | |
2112 klass = Universe::typeArrayKlassObj(t); | |
2113 } else { | |
2114 symbolHandle elem_name(THREAD, object_key); | |
2115 MutexLocker mu(SystemDictionary_lock, THREAD); | |
2116 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD); | |
2117 } | |
2118 if (klass != NULL) { | |
2119 klass = Klass::cast(klass)->array_klass_or_null(dimension); | |
2120 } | |
2121 } else { | |
2122 MutexLocker mu(SystemDictionary_lock, THREAD); | |
2123 // Non-array classes are easy: simply check the constraint table. | |
2124 klass = constraints()->find_constrained_klass(class_name, class_loader); | |
2125 } | |
2126 | |
2127 return klass; | |
2128 } | |
2129 | |
2130 | |
2131 bool SystemDictionary::add_loader_constraint(symbolHandle class_name, | |
2132 Handle class_loader1, | |
2133 Handle class_loader2, | |
2134 Thread* THREAD) { | |
2135 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1); | |
2136 int d_index1 = dictionary()->hash_to_index(d_hash1); | |
2137 | |
2138 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2); | |
2139 int d_index2 = dictionary()->hash_to_index(d_hash2); | |
2140 | |
2141 { | |
2142 MutexLocker mu_s(SystemDictionary_lock, THREAD); | |
2143 | |
2144 // Better never do a GC while we're holding these oops | |
2145 No_Safepoint_Verifier nosafepoint; | |
2146 | |
2147 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1); | |
2148 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2); | |
2149 return constraints()->add_entry(class_name, klass1, class_loader1, | |
2150 klass2, class_loader2); | |
2151 } | |
2152 } | |
2153 | |
2154 // Add entry to resolution error table to record the error when the first | |
2155 // attempt to resolve a reference to a class has failed. | |
2156 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) { | |
2157 unsigned int hash = resolution_errors()->compute_hash(pool, which); | |
2158 int index = resolution_errors()->hash_to_index(hash); | |
2159 { | |
2160 MutexLocker ml(SystemDictionary_lock, Thread::current()); | |
2161 resolution_errors()->add_entry(index, hash, pool, which, error); | |
2162 } | |
2163 } | |
2164 | |
2165 // Lookup resolution error table. Returns error if found, otherwise NULL. | |
2166 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { | |
2167 unsigned int hash = resolution_errors()->compute_hash(pool, which); | |
2168 int index = resolution_errors()->hash_to_index(hash); | |
2169 { | |
2170 MutexLocker ml(SystemDictionary_lock, Thread::current()); | |
2171 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); | |
2172 return (entry != NULL) ? entry->error() : (symbolOop)NULL; | |
2173 } | |
2174 } | |
2175 | |
2176 | |
2177 // Make sure all class components (including arrays) in the given | |
2178 // signature will be resolved to the same class in both loaders. | |
2179 // Returns the name of the type that failed a loader constraint check, or | |
2180 // NULL if no constraint failed. The returned C string needs cleaning up | |
2181 // with a ResourceMark in the caller | |
2182 char* SystemDictionary::check_signature_loaders(symbolHandle signature, | |
2183 Handle loader1, Handle loader2, | |
2184 bool is_method, TRAPS) { | |
2185 // Nothing to do if loaders are the same. | |
2186 if (loader1() == loader2()) { | |
2187 return NULL; | |
2188 } | |
2189 | |
2190 SignatureStream sig_strm(signature, is_method); | |
2191 while (!sig_strm.is_done()) { | |
2192 if (sig_strm.is_object()) { | |
2193 symbolOop s = sig_strm.as_symbol(CHECK_NULL); | |
2194 symbolHandle sig (THREAD, s); | |
2195 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { | |
2196 return sig()->as_C_string(); | |
2197 } | |
2198 } | |
2199 sig_strm.next(); | |
2200 } | |
2201 return NULL; | |
2202 } | |
2203 | |
2204 | |
2205 // Since the identity hash code for symbols changes when the symbols are | |
2206 // moved from the regular perm gen (hash in the mark word) to the shared | |
2207 // spaces (hash is the address), the classes loaded into the dictionary | |
2208 // may be in the wrong buckets. | |
2209 | |
2210 void SystemDictionary::reorder_dictionary() { | |
2211 dictionary()->reorder_dictionary(); | |
2212 } | |
2213 | |
2214 | |
2215 void SystemDictionary::copy_buckets(char** top, char* end) { | |
2216 dictionary()->copy_buckets(top, end); | |
2217 } | |
2218 | |
2219 | |
2220 void SystemDictionary::copy_table(char** top, char* end) { | |
2221 dictionary()->copy_table(top, end); | |
2222 } | |
2223 | |
2224 | |
2225 void SystemDictionary::reverse() { | |
2226 dictionary()->reverse(); | |
2227 } | |
2228 | |
2229 int SystemDictionary::number_of_classes() { | |
2230 return dictionary()->number_of_entries(); | |
2231 } | |
2232 | |
2233 | |
2234 // ---------------------------------------------------------------------------- | |
2235 #ifndef PRODUCT | |
2236 | |
2237 void SystemDictionary::print() { | |
2238 dictionary()->print(); | |
2239 | |
2240 // Placeholders | |
2241 GCMutexLocker mu(SystemDictionary_lock); | |
2242 placeholders()->print(); | |
2243 | |
2244 // loader constraints - print under SD_lock | |
2245 constraints()->print(); | |
2246 } | |
2247 | |
2248 #endif | |
2249 | |
2250 void SystemDictionary::verify() { | |
2251 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); | |
2252 guarantee(constraints() != NULL, | |
2253 "Verify of loader constraints failed"); | |
2254 guarantee(dictionary()->number_of_entries() >= 0 && | |
2255 placeholders()->number_of_entries() >= 0, | |
2256 "Verify of system dictionary failed"); | |
2257 | |
2258 // Verify dictionary | |
2259 dictionary()->verify(); | |
2260 | |
2261 GCMutexLocker mu(SystemDictionary_lock); | |
2262 placeholders()->verify(); | |
2263 | |
2264 // Verify constraint table | |
2265 guarantee(constraints() != NULL, "Verify of loader constraints failed"); | |
2266 constraints()->verify(dictionary()); | |
2267 } | |
2268 | |
2269 | |
2270 void SystemDictionary::verify_obj_klass_present(Handle obj, | |
2271 symbolHandle class_name, | |
2272 Handle class_loader) { | |
2273 GCMutexLocker mu(SystemDictionary_lock); | |
2274 oop probe = find_class_or_placeholder(class_name, class_loader); | |
2275 if (probe == NULL) { | |
2276 probe = SystemDictionary::find_shared_class(class_name); | |
2277 } | |
2278 guarantee(probe != NULL && | |
2279 (!probe->is_klass() || probe == obj()), | |
2280 "Loaded klasses should be in SystemDictionary"); | |
2281 } | |
2282 | |
2283 #ifndef PRODUCT | |
2284 | |
2285 // statistics code | |
2286 class ClassStatistics: AllStatic { | |
2287 private: | |
2288 static int nclasses; // number of classes | |
2289 static int nmethods; // number of methods | |
2290 static int nmethoddata; // number of methodData | |
2291 static int class_size; // size of class objects in words | |
2292 static int method_size; // size of method objects in words | |
2293 static int debug_size; // size of debug info in methods | |
2294 static int methoddata_size; // size of methodData objects in words | |
2295 | |
2296 static void do_class(klassOop k) { | |
2297 nclasses++; | |
2298 class_size += k->size(); | |
2299 if (k->klass_part()->oop_is_instance()) { | |
2300 instanceKlass* ik = (instanceKlass*)k->klass_part(); | |
2301 class_size += ik->methods()->size(); | |
2302 class_size += ik->constants()->size(); | |
2303 class_size += ik->local_interfaces()->size(); | |
2304 class_size += ik->transitive_interfaces()->size(); | |
2305 // We do not have to count implementors, since we only store one! | |
2306 class_size += ik->fields()->size(); | |
2307 } | |
2308 } | |
2309 | |
2310 static void do_method(methodOop m) { | |
2311 nmethods++; | |
2312 method_size += m->size(); | |
2313 // class loader uses same objArray for empty vectors, so don't count these | |
2314 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size(); | |
2315 if (m->has_stackmap_table()) { | |
2316 method_size += m->stackmap_data()->size(); | |
2317 } | |
2318 | |
2319 methodDataOop mdo = m->method_data(); | |
2320 if (mdo != NULL) { | |
2321 nmethoddata++; | |
2322 methoddata_size += mdo->size(); | |
2323 } | |
2324 } | |
2325 | |
2326 public: | |
2327 static void print() { | |
2328 SystemDictionary::classes_do(do_class); | |
2329 SystemDictionary::methods_do(do_method); | |
2330 tty->print_cr("Class statistics:"); | |
2331 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); | |
2332 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, | |
2333 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); | |
2334 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); | |
2335 } | |
2336 }; | |
2337 | |
2338 | |
2339 int ClassStatistics::nclasses = 0; | |
2340 int ClassStatistics::nmethods = 0; | |
2341 int ClassStatistics::nmethoddata = 0; | |
2342 int ClassStatistics::class_size = 0; | |
2343 int ClassStatistics::method_size = 0; | |
2344 int ClassStatistics::debug_size = 0; | |
2345 int ClassStatistics::methoddata_size = 0; | |
2346 | |
2347 void SystemDictionary::print_class_statistics() { | |
2348 ResourceMark rm; | |
2349 ClassStatistics::print(); | |
2350 } | |
2351 | |
2352 | |
2353 class MethodStatistics: AllStatic { | |
2354 public: | |
2355 enum { | |
2356 max_parameter_size = 10 | |
2357 }; | |
2358 private: | |
2359 | |
2360 static int _number_of_methods; | |
2361 static int _number_of_final_methods; | |
2362 static int _number_of_static_methods; | |
2363 static int _number_of_native_methods; | |
2364 static int _number_of_synchronized_methods; | |
2365 static int _number_of_profiled_methods; | |
2366 static int _number_of_bytecodes; | |
2367 static int _parameter_size_profile[max_parameter_size]; | |
2368 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; | |
2369 | |
2370 static void initialize() { | |
2371 _number_of_methods = 0; | |
2372 _number_of_final_methods = 0; | |
2373 _number_of_static_methods = 0; | |
2374 _number_of_native_methods = 0; | |
2375 _number_of_synchronized_methods = 0; | |
2376 _number_of_profiled_methods = 0; | |
2377 _number_of_bytecodes = 0; | |
2378 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; | |
2379 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; | |
2380 }; | |
2381 | |
2382 static void do_method(methodOop m) { | |
2383 _number_of_methods++; | |
2384 // collect flag info | |
2385 if (m->is_final() ) _number_of_final_methods++; | |
2386 if (m->is_static() ) _number_of_static_methods++; | |
2387 if (m->is_native() ) _number_of_native_methods++; | |
2388 if (m->is_synchronized()) _number_of_synchronized_methods++; | |
2389 if (m->method_data() != NULL) _number_of_profiled_methods++; | |
2390 // collect parameter size info (add one for receiver, if any) | |
2391 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; | |
2392 // collect bytecodes info | |
2393 { | |
2394 Thread *thread = Thread::current(); | |
2395 HandleMark hm(thread); | |
2396 BytecodeStream s(methodHandle(thread, m)); | |
2397 Bytecodes::Code c; | |
2398 while ((c = s.next()) >= 0) { | |
2399 _number_of_bytecodes++; | |
2400 _bytecodes_profile[c]++; | |
2401 } | |
2402 } | |
2403 } | |
2404 | |
2405 public: | |
2406 static void print() { | |
2407 initialize(); | |
2408 SystemDictionary::methods_do(do_method); | |
2409 // generate output | |
2410 tty->cr(); | |
2411 tty->print_cr("Method statistics (static):"); | |
2412 // flag distribution | |
2413 tty->cr(); | |
2414 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); | |
2415 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); | |
2416 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); | |
2417 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); | |
2418 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); | |
2419 // parameter size profile | |
2420 tty->cr(); | |
2421 { int tot = 0; | |
2422 int avg = 0; | |
2423 for (int i = 0; i < max_parameter_size; i++) { | |
2424 int n = _parameter_size_profile[i]; | |
2425 tot += n; | |
2426 avg += n*i; | |
2427 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); | |
2428 } | |
2429 assert(tot == _number_of_methods, "should be the same"); | |
2430 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); | |
2431 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); | |
2432 } | |
2433 // bytecodes profile | |
2434 tty->cr(); | |
2435 { int tot = 0; | |
2436 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { | |
2437 if (Bytecodes::is_defined(i)) { | |
2438 Bytecodes::Code c = Bytecodes::cast(i); | |
2439 int n = _bytecodes_profile[c]; | |
2440 tot += n; | |
2441 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); | |
2442 } | |
2443 } | |
2444 assert(tot == _number_of_bytecodes, "should be the same"); | |
2445 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); | |
2446 } | |
2447 tty->cr(); | |
2448 } | |
2449 }; | |
2450 | |
2451 int MethodStatistics::_number_of_methods; | |
2452 int MethodStatistics::_number_of_final_methods; | |
2453 int MethodStatistics::_number_of_static_methods; | |
2454 int MethodStatistics::_number_of_native_methods; | |
2455 int MethodStatistics::_number_of_synchronized_methods; | |
2456 int MethodStatistics::_number_of_profiled_methods; | |
2457 int MethodStatistics::_number_of_bytecodes; | |
2458 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; | |
2459 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; | |
2460 | |
2461 | |
2462 void SystemDictionary::print_method_statistics() { | |
2463 MethodStatistics::print(); | |
2464 } | |
2465 | |
2466 #endif // PRODUCT |