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