1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/verifier.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "gc_implementation/shared/markSweep.inline.hpp"
32 #include "gc_interface/collectedHeap.inline.hpp"
33 #include "interpreter/oopMapCache.hpp"
34 #include "interpreter/rewriter.hpp"
35 #include "jvmtifiles/jvmti.h"
36 #include "memory/genOopClosures.inline.hpp"
37 #include "memory/oopFactory.hpp"
38 #include "memory/permGen.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceOop.hpp"
41 #include "oops/methodOop.hpp"
42 #include "oops/objArrayKlassKlass.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbolOop.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiRedefineClassesTrace.hpp"
47 #include "runtime/fieldDescriptor.hpp"
48 #include "runtime/handles.inline.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "services/threadService.hpp"
52 #include "utilities/dtrace.hpp"
53 #ifdef TARGET_OS_FAMILY_linux
54 # include "thread_linux.inline.hpp"
55 #endif
56 #ifdef TARGET_OS_FAMILY_solaris
57 # include "thread_solaris.inline.hpp"
58 #endif
59 #ifdef TARGET_OS_FAMILY_windows
60 # include "thread_windows.inline.hpp"
61 #endif
62 #ifndef SERIALGC
63 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
64 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
65 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
66 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
67 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
68 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
69 #include "oops/oop.pcgc.inline.hpp"
70 #endif
71 #ifdef COMPILER1
72 #include "c1/c1_Compiler.hpp"
73 #endif
74
75 #ifdef DTRACE_ENABLED
76
77 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
78 char*, intptr_t, oop, intptr_t);
79 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
80 char*, intptr_t, oop, intptr_t, int);
81 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
82 char*, intptr_t, oop, intptr_t, int);
83 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
84 char*, intptr_t, oop, intptr_t, int);
85 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
86 char*, intptr_t, oop, intptr_t, int);
87 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
88 char*, intptr_t, oop, intptr_t, int);
89 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
90 char*, intptr_t, oop, intptr_t, int);
91 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
92 char*, intptr_t, oop, intptr_t, int);
93
94 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) \
95 { \
96 char* data = NULL; \
97 int len = 0; \
98 symbolOop name = (clss)->name(); \
99 if (name != NULL) { \
100 data = (char*)name->bytes(); \
101 len = name->utf8_length(); \
102 } \
103 HS_DTRACE_PROBE4(hotspot, class__initialization__##type, \
104 data, len, (clss)->class_loader(), thread_type); \
105 }
106
107 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
108 { \
109 char* data = NULL; \
110 int len = 0; \
111 symbolOop name = (clss)->name(); \
112 if (name != NULL) { \
113 data = (char*)name->bytes(); \
114 len = name->utf8_length(); \
115 } \
116 HS_DTRACE_PROBE5(hotspot, class__initialization__##type, \
117 data, len, (clss)->class_loader(), thread_type, wait); \
118 }
119
120 #else // ndef DTRACE_ENABLED
121
122 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
123 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
124
125 #endif // ndef DTRACE_ENABLED
126
127 bool instanceKlass::should_be_initialized() const {
128 return !is_initialized();
129 }
130
131 klassVtable* instanceKlass::vtable() const {
132 return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());
133 }
134
135 klassItable* instanceKlass::itable() const {
136 return new klassItable(as_klassOop());
137 }
138
139 void instanceKlass::eager_initialize(Thread *thread) {
140 if (!EagerInitialization) return;
141
142 if (this->is_not_initialized()) {
143 // abort if the the class has a class initializer
144 if (this->class_initializer() != NULL) return;
145
146 // abort if it is java.lang.Object (initialization is handled in genesis)
147 klassOop super = this->super();
148 if (super == NULL) return;
149
150 // abort if the super class should be initialized
151 if (!instanceKlass::cast(super)->is_initialized()) return;
152
153 // call body to expose the this pointer
154 instanceKlassHandle this_oop(thread, this->as_klassOop());
155 eager_initialize_impl(this_oop);
156 }
157 }
158
159
160 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
161 EXCEPTION_MARK;
162 ObjectLocker ol(this_oop, THREAD);
163
164 // abort if someone beat us to the initialization
165 if (!this_oop->is_not_initialized()) return; // note: not equivalent to is_initialized()
166
167 ClassState old_state = this_oop->_init_state;
168 link_class_impl(this_oop, true, THREAD);
169 if (HAS_PENDING_EXCEPTION) {
170 CLEAR_PENDING_EXCEPTION;
171 // Abort if linking the class throws an exception.
172
173 // Use a test to avoid redundantly resetting the state if there's
174 // no change. Set_init_state() asserts that state changes make
175 // progress, whereas here we might just be spinning in place.
176 if( old_state != this_oop->_init_state )
177 this_oop->set_init_state (old_state);
178 } else {
179 // linking successfull, mark class as initialized
180 this_oop->set_init_state (fully_initialized);
181 // trace
182 if (TraceClassInitialization) {
183 ResourceMark rm(THREAD);
184 tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
185 }
186 }
187 }
188
189
190 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
191 // process. The step comments refers to the procedure described in that section.
192 // Note: implementation moved to static method to expose the this pointer.
193 void instanceKlass::initialize(TRAPS) {
194 if (this->should_be_initialized()) {
195 HandleMark hm(THREAD);
196 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
197 initialize_impl(this_oop, CHECK);
198 // Note: at this point the class may be initialized
199 // OR it may be in the state of being initialized
200 // in case of recursive initialization!
201 } else {
202 assert(is_initialized(), "sanity check");
203 }
204 }
205
206
207 bool instanceKlass::verify_code(
208 instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
209 // 1) Verify the bytecodes
210 Verifier::Mode mode =
211 throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
212 return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
213 }
214
215
216 // Used exclusively by the shared spaces dump mechanism to prevent
217 // classes mapped into the shared regions in new VMs from appearing linked.
218
219 void instanceKlass::unlink_class() {
220 assert(is_linked(), "must be linked");
221 _init_state = loaded;
222 }
223
224 void instanceKlass::link_class(TRAPS) {
225 assert(is_loaded(), "must be loaded");
226 if (!is_linked()) {
227 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
228 link_class_impl(this_oop, true, CHECK);
229 }
230 }
231
232 // Called to verify that a class can link during initialization, without
233 // throwing a VerifyError.
234 bool instanceKlass::link_class_or_fail(TRAPS) {
235 assert(is_loaded(), "must be loaded");
236 if (!is_linked()) {
237 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
238 link_class_impl(this_oop, false, CHECK_false);
239 }
240 return is_linked();
241 }
242
243 bool instanceKlass::link_class_impl(
244 instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
245 // check for error state
246 if (this_oop->is_in_error_state()) {
247 ResourceMark rm(THREAD);
248 THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
249 this_oop->external_name(), false);
250 }
251 // return if already verified
252 if (this_oop->is_linked()) {
253 return true;
254 }
255
256 // Timing
257 // timer handles recursion
258 assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
259 JavaThread* jt = (JavaThread*)THREAD;
260
261 // link super class before linking this class
262 instanceKlassHandle super(THREAD, this_oop->super());
263 if (super.not_null()) {
264 if (super->is_interface()) { // check if super class is an interface
265 ResourceMark rm(THREAD);
266 Exceptions::fthrow(
267 THREAD_AND_LOCATION,
268 vmSymbolHandles::java_lang_IncompatibleClassChangeError(),
269 "class %s has interface %s as super class",
270 this_oop->external_name(),
271 super->external_name()
272 );
273 return false;
274 }
275
276 link_class_impl(super, throw_verifyerror, CHECK_false);
277 }
278
279 // link all interfaces implemented by this class before linking this class
280 objArrayHandle interfaces (THREAD, this_oop->local_interfaces());
281 int num_interfaces = interfaces->length();
282 for (int index = 0; index < num_interfaces; index++) {
283 HandleMark hm(THREAD);
284 instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));
285 link_class_impl(ih, throw_verifyerror, CHECK_false);
286 }
287
288 // in case the class is linked in the process of linking its superclasses
289 if (this_oop->is_linked()) {
290 return true;
291 }
292
293 // trace only the link time for this klass that includes
294 // the verification time
295 PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
296 ClassLoader::perf_class_link_selftime(),
297 ClassLoader::perf_classes_linked(),
298 jt->get_thread_stat()->perf_recursion_counts_addr(),
299 jt->get_thread_stat()->perf_timers_addr(),
300 PerfClassTraceTime::CLASS_LINK);
301
302 // verification & rewriting
303 {
304 ObjectLocker ol(this_oop, THREAD);
305 // rewritten will have been set if loader constraint error found
306 // on an earlier link attempt
307 // don't verify or rewrite if already rewritten
308 if (!this_oop->is_linked()) {
309 if (!this_oop->is_rewritten()) {
310 {
311 // Timer includes any side effects of class verification (resolution,
312 // etc), but not recursive entry into verify_code().
313 PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
314 ClassLoader::perf_class_verify_selftime(),
315 ClassLoader::perf_classes_verified(),
316 jt->get_thread_stat()->perf_recursion_counts_addr(),
317 jt->get_thread_stat()->perf_timers_addr(),
318 PerfClassTraceTime::CLASS_VERIFY);
319 bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
320 if (!verify_ok) {
321 return false;
322 }
323 }
324
325 // Just in case a side-effect of verify linked this class already
326 // (which can sometimes happen since the verifier loads classes
327 // using custom class loaders, which are free to initialize things)
328 if (this_oop->is_linked()) {
329 return true;
330 }
331
332 // also sets rewritten
333 this_oop->rewrite_class(CHECK_false);
334 }
335
336 // Initialize the vtable and interface table after
337 // methods have been rewritten since rewrite may
338 // fabricate new methodOops.
339 // also does loader constraint checking
340 if (!this_oop()->is_shared()) {
341 ResourceMark rm(THREAD);
342 this_oop->vtable()->initialize_vtable(true, CHECK_false);
343 this_oop->itable()->initialize_itable(true, CHECK_false);
344 }
345 #ifdef ASSERT
346 else {
347 ResourceMark rm(THREAD);
348 this_oop->vtable()->verify(tty, true);
349 // In case itable verification is ever added.
350 // this_oop->itable()->verify(tty, true);
351 }
352 #endif
353 this_oop->set_init_state(linked);
354 if (JvmtiExport::should_post_class_prepare()) {
355 Thread *thread = THREAD;
356 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
357 JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
358 }
359 }
360 }
361 return true;
362 }
363
364
365 // Rewrite the byte codes of all of the methods of a class.
366 // Three cases:
367 // During the link of a newly loaded class.
368 // During the preloading of classes to be written to the shared spaces.
369 // - Rewrite the methods and update the method entry points.
370 //
371 // During the link of a class in the shared spaces.
372 // - The methods were already rewritten, update the metho entry points.
373 //
374 // The rewriter must be called exactly once. Rewriting must happen after
375 // verification but before the first method of the class is executed.
376
377 void instanceKlass::rewrite_class(TRAPS) {
378 assert(is_loaded(), "must be loaded");
379 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
380 if (this_oop->is_rewritten()) {
381 assert(this_oop()->is_shared(), "rewriting an unshared class?");
382 return;
383 }
384 Rewriter::rewrite(this_oop, CHECK); // No exception can happen here
385 this_oop->set_rewritten();
386 }
387
388
389 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
390 // Make sure klass is linked (verified) before initialization
391 // A class could already be verified, since it has been reflected upon.
392 this_oop->link_class(CHECK);
393
394 DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);
395
396 bool wait = false;
397
398 // refer to the JVM book page 47 for description of steps
399 // Step 1
400 { ObjectLocker ol(this_oop, THREAD);
401
402 Thread *self = THREAD; // it's passed the current thread
403
404 // Step 2
405 // If we were to use wait() instead of waitInterruptibly() then
406 // we might end up throwing IE from link/symbol resolution sites
407 // that aren't expected to throw. This would wreak havoc. See 6320309.
408 while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
409 wait = true;
410 ol.waitUninterruptibly(CHECK);
411 }
412
413 // Step 3
414 if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
415 DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);
416 return;
417 }
418
419 // Step 4
420 if (this_oop->is_initialized()) {
421 DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);
422 return;
423 }
424
425 // Step 5
426 if (this_oop->is_in_error_state()) {
427 DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);
428 ResourceMark rm(THREAD);
429 const char* desc = "Could not initialize class ";
430 const char* className = this_oop->external_name();
431 size_t msglen = strlen(desc) + strlen(className) + 1;
432 char* message = NEW_RESOURCE_ARRAY(char, msglen);
433 if (NULL == message) {
434 // Out of memory: can't create detailed error message
435 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
436 } else {
437 jio_snprintf(message, msglen, "%s%s", desc, className);
438 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
439 }
440 }
441
442 // Step 6
443 this_oop->set_init_state(being_initialized);
444 this_oop->set_init_thread(self);
445 }
446
447 // Step 7
448 klassOop super_klass = this_oop->super();
449 if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {
450 Klass::cast(super_klass)->initialize(THREAD);
451
452 if (HAS_PENDING_EXCEPTION) {
453 Handle e(THREAD, PENDING_EXCEPTION);
454 CLEAR_PENDING_EXCEPTION;
455 {
456 EXCEPTION_MARK;
457 this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
458 CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, superclass initialization error is thrown below
459 }
460 DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);
461 THROW_OOP(e());
462 }
463 }
464
465 // Step 8
466 {
467 assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
468 JavaThread* jt = (JavaThread*)THREAD;
469 DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);
470 // Timer includes any side effects of class initialization (resolution,
471 // etc), but not recursive entry into call_class_initializer().
472 PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
473 ClassLoader::perf_class_init_selftime(),
474 ClassLoader::perf_classes_inited(),
475 jt->get_thread_stat()->perf_recursion_counts_addr(),
476 jt->get_thread_stat()->perf_timers_addr(),
477 PerfClassTraceTime::CLASS_CLINIT);
478 this_oop->call_class_initializer(THREAD);
479 }
480
481 // Step 9
482 if (!HAS_PENDING_EXCEPTION) {
483 this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
484 { ResourceMark rm(THREAD);
485 debug_only(this_oop->vtable()->verify(tty, true);)
486 }
487 }
488 else {
489 // Step 10 and 11
490 Handle e(THREAD, PENDING_EXCEPTION);
491 CLEAR_PENDING_EXCEPTION;
492 {
493 EXCEPTION_MARK;
494 this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
495 CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, class initialization error is thrown below
496 }
497 DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);
498 if (e->is_a(SystemDictionary::Error_klass())) {
499 THROW_OOP(e());
500 } else {
501 JavaCallArguments args(e);
502 THROW_ARG(vmSymbolHandles::java_lang_ExceptionInInitializerError(),
503 vmSymbolHandles::throwable_void_signature(),
504 &args);
505 }
506 }
507 DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);
508 }
509
510
511 // Note: implementation moved to static method to expose the this pointer.
512 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
513 instanceKlassHandle kh(THREAD, this->as_klassOop());
514 set_initialization_state_and_notify_impl(kh, state, CHECK);
515 }
516
517 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
518 ObjectLocker ol(this_oop, THREAD);
519 this_oop->set_init_state(state);
520 ol.notify_all(CHECK);
521 }
522
523 void instanceKlass::add_implementor(klassOop k) {
524 assert(Compile_lock->owned_by_self(), "");
525 // Filter out my subinterfaces.
526 // (Note: Interfaces are never on the subklass list.)
527 if (instanceKlass::cast(k)->is_interface()) return;
528
529 // Filter out subclasses whose supers already implement me.
530 // (Note: CHA must walk subclasses of direct implementors
531 // in order to locate indirect implementors.)
532 klassOop sk = instanceKlass::cast(k)->super();
533 if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))
534 // We only need to check one immediate superclass, since the
535 // implements_interface query looks at transitive_interfaces.
536 // Any supers of the super have the same (or fewer) transitive_interfaces.
537 return;
538
539 // Update number of implementors
540 int i = _nof_implementors++;
541
542 // Record this implementor, if there are not too many already
543 if (i < implementors_limit) {
544 assert(_implementors[i] == NULL, "should be exactly one implementor");
545 oop_store_without_check((oop*)&_implementors[i], k);
546 } else if (i == implementors_limit) {
547 // clear out the list on first overflow
548 for (int i2 = 0; i2 < implementors_limit; i2++)
549 oop_store_without_check((oop*)&_implementors[i2], NULL);
550 }
551
552 // The implementor also implements the transitive_interfaces
553 for (int index = 0; index < local_interfaces()->length(); index++) {
554 instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);
555 }
556 }
557
558 void instanceKlass::init_implementor() {
559 for (int i = 0; i < implementors_limit; i++)
560 oop_store_without_check((oop*)&_implementors[i], NULL);
561 _nof_implementors = 0;
562 }
563
564
565 void instanceKlass::process_interfaces(Thread *thread) {
566 // link this class into the implementors list of every interface it implements
567 KlassHandle this_as_oop (thread, this->as_klassOop());
568 for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
569 assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");
570 instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));
571 assert(interf->is_interface(), "expected interface");
572 interf->add_implementor(this_as_oop());
573 }
574 }
575
576 bool instanceKlass::can_be_primary_super_slow() const {
577 if (is_interface())
578 return false;
579 else
580 return Klass::can_be_primary_super_slow();
581 }
582
583 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
584 // The secondaries are the implemented interfaces.
585 instanceKlass* ik = instanceKlass::cast(as_klassOop());
586 objArrayHandle interfaces (THREAD, ik->transitive_interfaces());
587 int num_secondaries = num_extra_slots + interfaces->length();
588 if (num_secondaries == 0) {
589 return Universe::the_empty_system_obj_array();
590 } else if (num_extra_slots == 0) {
591 return interfaces();
592 } else {
593 // a mix of both
594 objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);
595 for (int i = 0; i < interfaces->length(); i++) {
596 secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));
597 }
598 return secondaries;
599 }
600 }
601
602 bool instanceKlass::compute_is_subtype_of(klassOop k) {
603 if (Klass::cast(k)->is_interface()) {
604 return implements_interface(k);
605 } else {
606 return Klass::compute_is_subtype_of(k);
607 }
608 }
609
610 bool instanceKlass::implements_interface(klassOop k) const {
611 if (as_klassOop() == k) return true;
612 assert(Klass::cast(k)->is_interface(), "should be an interface class");
613 for (int i = 0; i < transitive_interfaces()->length(); i++) {
614 if (transitive_interfaces()->obj_at(i) == k) {
615 return true;
616 }
617 }
618 return false;
619 }
620
621 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {
622 if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
623 if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
624 report_java_out_of_memory("Requested array size exceeds VM limit");
625 THROW_OOP_0(Universe::out_of_memory_error_array_size());
626 }
627 int size = objArrayOopDesc::object_size(length);
628 klassOop ak = array_klass(n, CHECK_NULL);
629 KlassHandle h_ak (THREAD, ak);
630 objArrayOop o =
631 (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
632 return o;
633 }
634
635 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {
636 if (TraceFinalizerRegistration) {
637 tty->print("Registered ");
638 i->print_value_on(tty);
639 tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
640 }
641 instanceHandle h_i(THREAD, i);
642 // Pass the handle as argument, JavaCalls::call expects oop as jobjects
643 JavaValue result(T_VOID);
644 JavaCallArguments args(h_i);
645 methodHandle mh (THREAD, Universe::finalizer_register_method());
646 JavaCalls::call(&result, mh, &args, CHECK_NULL);
647 return h_i();
648 }
649
650 instanceOop instanceKlass::allocate_instance(TRAPS) {
651 bool has_finalizer_flag = has_finalizer(); // Query before possible GC
652 int size = size_helper(); // Query before forming handle.
653
654 KlassHandle h_k(THREAD, as_klassOop());
655
656 instanceOop i;
657
658 i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
659 if (has_finalizer_flag && !RegisterFinalizersAtInit) {
660 i = register_finalizer(i, CHECK_NULL);
661 }
662 return i;
663 }
664
665 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {
666 // Finalizer registration occurs in the Object.<init> constructor
667 // and constructors normally aren't run when allocating perm
668 // instances so simply disallow finalizable perm objects. This can
669 // be relaxed if a need for it is found.
670 assert(!has_finalizer(), "perm objects not allowed to have finalizers");
671 int size = size_helper(); // Query before forming handle.
672 KlassHandle h_k(THREAD, as_klassOop());
673 instanceOop i = (instanceOop)
674 CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
675 return i;
676 }
677
678 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
679 if (is_interface() || is_abstract()) {
680 ResourceMark rm(THREAD);
681 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
682 : vmSymbols::java_lang_InstantiationException(), external_name());
683 }
684 if (as_klassOop() == SystemDictionary::Class_klass()) {
685 ResourceMark rm(THREAD);
686 THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
687 : vmSymbols::java_lang_IllegalAccessException(), external_name());
688 }
689 }
690
691 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
692 instanceKlassHandle this_oop(THREAD, as_klassOop());
693 return array_klass_impl(this_oop, or_null, n, THREAD);
694 }
695
696 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
697 if (this_oop->array_klasses() == NULL) {
698 if (or_null) return NULL;
699
700 ResourceMark rm;
701 JavaThread *jt = (JavaThread *)THREAD;
702 {
703 // Atomic creation of array_klasses
704 MutexLocker mc(Compile_lock, THREAD); // for vtables
705 MutexLocker ma(MultiArray_lock, THREAD);
706
707 // Check if update has already taken place
708 if (this_oop->array_klasses() == NULL) {
709 objArrayKlassKlass* oakk =
710 (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();
711
712 klassOop k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);
713 this_oop->set_array_klasses(k);
714 }
715 }
716 }
717 // _this will always be set at this point
718 objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();
719 if (or_null) {
720 return oak->array_klass_or_null(n);
721 }
722 return oak->array_klass(n, CHECK_NULL);
723 }
724
725 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {
726 return array_klass_impl(or_null, 1, THREAD);
727 }
728
729 void instanceKlass::call_class_initializer(TRAPS) {
730 instanceKlassHandle ik (THREAD, as_klassOop());
731 call_class_initializer_impl(ik, THREAD);
732 }
733
734 static int call_class_initializer_impl_counter = 0; // for debugging
735
736 methodOop instanceKlass::class_initializer() {
737 return find_method(vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
738 }
739
740 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
741 methodHandle h_method(THREAD, this_oop->class_initializer());
742 assert(!this_oop->is_initialized(), "we cannot initialize twice");
743 if (TraceClassInitialization) {
744 tty->print("%d Initializing ", call_class_initializer_impl_counter++);
745 this_oop->name()->print_value();
746 tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
747 }
748 if (h_method() != NULL) {
749 JavaCallArguments args; // No arguments
750 JavaValue result(T_VOID);
751 JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
752 }
753 }
754
755
756 void instanceKlass::mask_for(methodHandle method, int bci,
757 InterpreterOopMap* entry_for) {
758 // Dirty read, then double-check under a lock.
759 if (_oop_map_cache == NULL) {
760 // Otherwise, allocate a new one.
761 MutexLocker x(OopMapCacheAlloc_lock);
762 // First time use. Allocate a cache in C heap
763 if (_oop_map_cache == NULL) {
764 _oop_map_cache = new OopMapCache();
765 }
766 }
767 // _oop_map_cache is constant after init; lookup below does is own locking.
768 _oop_map_cache->lookup(method, bci, entry_for);
769 }
770
771
772 bool instanceKlass::find_local_field(symbolOop name, symbolOop sig, fieldDescriptor* fd) const {
773 const int n = fields()->length();
774 for (int i = 0; i < n; i += next_offset ) {
775 int name_index = fields()->ushort_at(i + name_index_offset);
776 int sig_index = fields()->ushort_at(i + signature_index_offset);
777 symbolOop f_name = constants()->symbol_at(name_index);
778 symbolOop f_sig = constants()->symbol_at(sig_index);
779 if (f_name == name && f_sig == sig) {
780 fd->initialize(as_klassOop(), i);
781 return true;
782 }
783 }
784 return false;
785 }
786
787
788 void instanceKlass::field_names_and_sigs_iterate(OopClosure* closure) {
789 const int n = fields()->length();
790 for (int i = 0; i < n; i += next_offset ) {
791 int name_index = fields()->ushort_at(i + name_index_offset);
792 symbolOop name = constants()->symbol_at(name_index);
793 closure->do_oop((oop*)&name);
794
795 int sig_index = fields()->ushort_at(i + signature_index_offset);
796 symbolOop sig = constants()->symbol_at(sig_index);
797 closure->do_oop((oop*)&sig);
798 }
799 }
800
801
802 klassOop instanceKlass::find_interface_field(symbolOop name, symbolOop sig, fieldDescriptor* fd) const {
803 const int n = local_interfaces()->length();
804 for (int i = 0; i < n; i++) {
805 klassOop intf1 = klassOop(local_interfaces()->obj_at(i));
806 assert(Klass::cast(intf1)->is_interface(), "just checking type");
807 // search for field in current interface
808 if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
809 assert(fd->is_static(), "interface field must be static");
810 return intf1;
811 }
812 // search for field in direct superinterfaces
813 klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
814 if (intf2 != NULL) return intf2;
815 }
816 // otherwise field lookup fails
817 return NULL;
818 }
819
820
821 klassOop instanceKlass::find_field(symbolOop name, symbolOop sig, fieldDescriptor* fd) const {
822 // search order according to newest JVM spec (5.4.3.2, p.167).
823 // 1) search for field in current klass
824 if (find_local_field(name, sig, fd)) {
825 return as_klassOop();
826 }
827 // 2) search for field recursively in direct superinterfaces
828 { klassOop intf = find_interface_field(name, sig, fd);
829 if (intf != NULL) return intf;
830 }
831 // 3) apply field lookup recursively if superclass exists
832 { klassOop supr = super();
833 if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);
834 }
835 // 4) otherwise field lookup fails
836 return NULL;
837 }
838
839
840 klassOop instanceKlass::find_field(symbolOop name, symbolOop sig, bool is_static, fieldDescriptor* fd) const {
841 // search order according to newest JVM spec (5.4.3.2, p.167).
842 // 1) search for field in current klass
843 if (find_local_field(name, sig, fd)) {
844 if (fd->is_static() == is_static) return as_klassOop();
845 }
846 // 2) search for field recursively in direct superinterfaces
847 if (is_static) {
848 klassOop intf = find_interface_field(name, sig, fd);
849 if (intf != NULL) return intf;
850 }
851 // 3) apply field lookup recursively if superclass exists
852 { klassOop supr = super();
853 if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
854 }
855 // 4) otherwise field lookup fails
856 return NULL;
857 }
858
859
860 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
861 int length = fields()->length();
862 for (int i = 0; i < length; i += next_offset) {
863 if (offset_from_fields( i ) == offset) {
864 fd->initialize(as_klassOop(), i);
865 if (fd->is_static() == is_static) return true;
866 }
867 }
868 return false;
869 }
870
871
872 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
873 klassOop klass = as_klassOop();
874 while (klass != NULL) {
875 if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
876 return true;
877 }
878 klass = Klass::cast(klass)->super();
879 }
880 return false;
881 }
882
883
884 void instanceKlass::methods_do(void f(methodOop method)) {
885 int len = methods()->length();
886 for (int index = 0; index < len; index++) {
887 methodOop m = methodOop(methods()->obj_at(index));
888 assert(m->is_method(), "must be method");
889 f(m);
890 }
891 }
892
893 void instanceKlass::do_local_static_fields(FieldClosure* cl) {
894 fieldDescriptor fd;
895 int length = fields()->length();
896 for (int i = 0; i < length; i += next_offset) {
897 fd.initialize(as_klassOop(), i);
898 if (fd.is_static()) cl->do_field(&fd);
899 }
900 }
901
902
903 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
904 instanceKlassHandle h_this(THREAD, as_klassOop());
905 do_local_static_fields_impl(h_this, f, CHECK);
906 }
907
908
909 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
910 fieldDescriptor fd;
911 int length = this_oop->fields()->length();
912 for (int i = 0; i < length; i += next_offset) {
913 fd.initialize(this_oop(), i);
914 if (fd.is_static()) { f(&fd, CHECK); } // Do NOT remove {}! (CHECK macro expands into several statements)
915 }
916 }
917
918
919 static int compare_fields_by_offset(int* a, int* b) {
920 return a[0] - b[0];
921 }
922
923 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {
924 instanceKlass* super = superklass();
925 if (super != NULL) {
926 super->do_nonstatic_fields(cl);
927 }
928 fieldDescriptor fd;
929 int length = fields()->length();
930 // In DebugInfo nonstatic fields are sorted by offset.
931 int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1));
932 int j = 0;
933 for (int i = 0; i < length; i += next_offset) {
934 fd.initialize(as_klassOop(), i);
935 if (!fd.is_static()) {
936 fields_sorted[j + 0] = fd.offset();
937 fields_sorted[j + 1] = i;
938 j += 2;
939 }
940 }
941 if (j > 0) {
942 length = j;
943 // _sort_Fn is defined in growableArray.hpp.
944 qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
945 for (int i = 0; i < length; i += 2) {
946 fd.initialize(as_klassOop(), fields_sorted[i + 1]);
947 assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
948 cl->do_field(&fd);
949 }
950 }
951 FREE_C_HEAP_ARRAY(int, fields_sorted);
952 }
953
954
955 void instanceKlass::array_klasses_do(void f(klassOop k)) {
956 if (array_klasses() != NULL)
957 arrayKlass::cast(array_klasses())->array_klasses_do(f);
958 }
959
960
961 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {
962 f(as_klassOop());
963 array_klasses_do(f);
964 }
965
966 #ifdef ASSERT
967 static int linear_search(objArrayOop methods, symbolOop name, symbolOop signature) {
968 int len = methods->length();
969 for (int index = 0; index < len; index++) {
970 methodOop m = (methodOop)(methods->obj_at(index));
971 assert(m->is_method(), "must be method");
972 if (m->signature() == signature && m->name() == name) {
973 return index;
974 }
975 }
976 return -1;
977 }
978 #endif
979
980 methodOop instanceKlass::find_method(symbolOop name, symbolOop signature) const {
981 return instanceKlass::find_method(methods(), name, signature);
982 }
983
984 methodOop instanceKlass::find_method(objArrayOop methods, symbolOop name, symbolOop signature) {
985 int len = methods->length();
986 // methods are sorted, so do binary search
987 int l = 0;
988 int h = len - 1;
989 while (l <= h) {
990 int mid = (l + h) >> 1;
991 methodOop m = (methodOop)methods->obj_at(mid);
992 assert(m->is_method(), "must be method");
993 int res = m->name()->fast_compare(name);
994 if (res == 0) {
995 // found matching name; do linear search to find matching signature
996 // first, quick check for common case
997 if (m->signature() == signature) return m;
998 // search downwards through overloaded methods
999 int i;
1000 for (i = mid - 1; i >= l; i--) {
1001 methodOop m = (methodOop)methods->obj_at(i);
1002 assert(m->is_method(), "must be method");
1003 if (m->name() != name) break;
1004 if (m->signature() == signature) return m;
1005 }
1006 // search upwards
1007 for (i = mid + 1; i <= h; i++) {
1008 methodOop m = (methodOop)methods->obj_at(i);
1009 assert(m->is_method(), "must be method");
1010 if (m->name() != name) break;
1011 if (m->signature() == signature) return m;
1012 }
1013 // not found
1014 #ifdef ASSERT
1015 int index = linear_search(methods, name, signature);
1016 assert(index == -1, err_msg("binary search should have found entry %d", index));
1017 #endif
1018 return NULL;
1019 } else if (res < 0) {
1020 l = mid + 1;
1021 } else {
1022 h = mid - 1;
1023 }
1024 }
1025 #ifdef ASSERT
1026 int index = linear_search(methods, name, signature);
1027 assert(index == -1, err_msg("binary search should have found entry %d", index));
1028 #endif
1029 return NULL;
1030 }
1031
1032 methodOop instanceKlass::uncached_lookup_method(symbolOop name, symbolOop signature) const {
1033 klassOop klass = as_klassOop();
1034 while (klass != NULL) {
1035 methodOop method = instanceKlass::cast(klass)->find_method(name, signature);
1036 if (method != NULL) return method;
1037 klass = instanceKlass::cast(klass)->super();
1038 }
1039 return NULL;
1040 }
1041
1042 // lookup a method in all the interfaces that this class implements
1043 methodOop instanceKlass::lookup_method_in_all_interfaces(symbolOop name,
1044 symbolOop signature) const {
1045 objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();
1046 int num_ifs = all_ifs->length();
1047 instanceKlass *ik = NULL;
1048 for (int i = 0; i < num_ifs; i++) {
1049 ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));
1050 methodOop m = ik->lookup_method(name, signature);
1051 if (m != NULL) {
1052 return m;
1053 }
1054 }
1055 return NULL;
1056 }
1057
1058 /* jni_id_for_impl for jfieldIds only */
1059 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
1060 MutexLocker ml(JfieldIdCreation_lock);
1061 // Retry lookup after we got the lock
1062 JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
1063 if (probe == NULL) {
1064 // Slow case, allocate new static field identifier
1065 probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());
1066 this_oop->set_jni_ids(probe);
1067 }
1068 return probe;
1069 }
1070
1071
1072 /* jni_id_for for jfieldIds only */
1073 JNIid* instanceKlass::jni_id_for(int offset) {
1074 JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1075 if (probe == NULL) {
1076 probe = jni_id_for_impl(this->as_klassOop(), offset);
1077 }
1078 return probe;
1079 }
1080
1081
1082 // Lookup or create a jmethodID.
1083 // This code is called by the VMThread and JavaThreads so the
1084 // locking has to be done very carefully to avoid deadlocks
1085 // and/or other cache consistency problems.
1086 //
1087 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
1088 size_t idnum = (size_t)method_h->method_idnum();
1089 jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1090 size_t length = 0;
1091 jmethodID id = NULL;
1092
1093 // We use a double-check locking idiom here because this cache is
1094 // performance sensitive. In the normal system, this cache only
1095 // transitions from NULL to non-NULL which is safe because we use
1096 // release_set_methods_jmethod_ids() to advertise the new cache.
1097 // A partially constructed cache should never be seen by a racing
1098 // thread. We also use release_store_ptr() to save a new jmethodID
1099 // in the cache so a partially constructed jmethodID should never be
1100 // seen either. Cache reads of existing jmethodIDs proceed without a
1101 // lock, but cache writes of a new jmethodID requires uniqueness and
1102 // creation of the cache itself requires no leaks so a lock is
1103 // generally acquired in those two cases.
1104 //
1105 // If the RedefineClasses() API has been used, then this cache can
1106 // grow and we'll have transitions from non-NULL to bigger non-NULL.
1107 // Cache creation requires no leaks and we require safety between all
1108 // cache accesses and freeing of the old cache so a lock is generally
1109 // acquired when the RedefineClasses() API has been used.
1110
1111 if (jmeths != NULL) {
1112 // the cache already exists
1113 if (!ik_h->idnum_can_increment()) {
1114 // the cache can't grow so we can just get the current values
1115 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1116 } else {
1117 // cache can grow so we have to be more careful
1118 if (Threads::number_of_threads() == 0 ||
1119 SafepointSynchronize::is_at_safepoint()) {
1120 // we're single threaded or at a safepoint - no locking needed
1121 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1122 } else {
1123 MutexLocker ml(JmethodIdCreation_lock);
1124 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1125 }
1126 }
1127 }
1128 // implied else:
1129 // we need to allocate a cache so default length and id values are good
1130
1131 if (jmeths == NULL || // no cache yet
1132 length <= idnum || // cache is too short
1133 id == NULL) { // cache doesn't contain entry
1134
1135 // This function can be called by the VMThread so we have to do all
1136 // things that might block on a safepoint before grabbing the lock.
1137 // Otherwise, we can deadlock with the VMThread or have a cache
1138 // consistency issue. These vars keep track of what we might have
1139 // to free after the lock is dropped.
1140 jmethodID to_dealloc_id = NULL;
1141 jmethodID* to_dealloc_jmeths = NULL;
1142
1143 // may not allocate new_jmeths or use it if we allocate it
1144 jmethodID* new_jmeths = NULL;
1145 if (length <= idnum) {
1146 // allocate a new cache that might be used
1147 size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
1148 new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);
1149 memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1150 // cache size is stored in element[0], other elements offset by one
1151 new_jmeths[0] = (jmethodID)size;
1152 }
1153
1154 // allocate a new jmethodID that might be used
1155 jmethodID new_id = NULL;
1156 if (method_h->is_old() && !method_h->is_obsolete()) {
1157 // The method passed in is old (but not obsolete), we need to use the current version
1158 methodOop current_method = ik_h->method_with_idnum((int)idnum);
1159 assert(current_method != NULL, "old and but not obsolete, so should exist");
1160 methodHandle current_method_h(current_method == NULL? method_h() : current_method);
1161 new_id = JNIHandles::make_jmethod_id(current_method_h);
1162 } else {
1163 // It is the current version of the method or an obsolete method,
1164 // use the version passed in
1165 new_id = JNIHandles::make_jmethod_id(method_h);
1166 }
1167
1168 if (Threads::number_of_threads() == 0 ||
1169 SafepointSynchronize::is_at_safepoint()) {
1170 // we're single threaded or at a safepoint - no locking needed
1171 id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1172 &to_dealloc_id, &to_dealloc_jmeths);
1173 } else {
1174 MutexLocker ml(JmethodIdCreation_lock);
1175 id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1176 &to_dealloc_id, &to_dealloc_jmeths);
1177 }
1178
1179 // The lock has been dropped so we can free resources.
1180 // Free up either the old cache or the new cache if we allocated one.
1181 if (to_dealloc_jmeths != NULL) {
1182 FreeHeap(to_dealloc_jmeths);
1183 }
1184 // free up the new ID since it wasn't needed
1185 if (to_dealloc_id != NULL) {
1186 JNIHandles::destroy_jmethod_id(to_dealloc_id);
1187 }
1188 }
1189 return id;
1190 }
1191
1192
1193 // Common code to fetch the jmethodID from the cache or update the
1194 // cache with the new jmethodID. This function should never do anything
1195 // that causes the caller to go to a safepoint or we can deadlock with
1196 // the VMThread or have cache consistency issues.
1197 //
1198 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
1199 instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
1200 jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1201 jmethodID** to_dealloc_jmeths_p) {
1202 assert(new_id != NULL, "sanity check");
1203 assert(to_dealloc_id_p != NULL, "sanity check");
1204 assert(to_dealloc_jmeths_p != NULL, "sanity check");
1205 assert(Threads::number_of_threads() == 0 ||
1206 SafepointSynchronize::is_at_safepoint() ||
1207 JmethodIdCreation_lock->owned_by_self(), "sanity check");
1208
1209 // reacquire the cache - we are locked, single threaded or at a safepoint
1210 jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1211 jmethodID id = NULL;
1212 size_t length = 0;
1213
1214 if (jmeths == NULL || // no cache yet
1215 (length = (size_t)jmeths[0]) <= idnum) { // cache is too short
1216 if (jmeths != NULL) {
1217 // copy any existing entries from the old cache
1218 for (size_t index = 0; index < length; index++) {
1219 new_jmeths[index+1] = jmeths[index+1];
1220 }
1221 *to_dealloc_jmeths_p = jmeths; // save old cache for later delete
1222 }
1223 ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
1224 } else {
1225 // fetch jmethodID (if any) from the existing cache
1226 id = jmeths[idnum+1];
1227 *to_dealloc_jmeths_p = new_jmeths; // save new cache for later delete
1228 }
1229 if (id == NULL) {
1230 // No matching jmethodID in the existing cache or we have a new
1231 // cache or we just grew the cache. This cache write is done here
1232 // by the first thread to win the foot race because a jmethodID
1233 // needs to be unique once it is generally available.
1234 id = new_id;
1235
1236 // The jmethodID cache can be read while unlocked so we have to
1237 // make sure the new jmethodID is complete before installing it
1238 // in the cache.
1239 OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1240 } else {
1241 *to_dealloc_id_p = new_id; // save new id for later delete
1242 }
1243 return id;
1244 }
1245
1246
1247 // Common code to get the jmethodID cache length and the jmethodID
1248 // value at index idnum if there is one.
1249 //
1250 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1251 size_t idnum, size_t *length_p, jmethodID* id_p) {
1252 assert(cache != NULL, "sanity check");
1253 assert(length_p != NULL, "sanity check");
1254 assert(id_p != NULL, "sanity check");
1255
1256 // cache size is stored in element[0], other elements offset by one
1257 *length_p = (size_t)cache[0];
1258 if (*length_p <= idnum) { // cache is too short
1259 *id_p = NULL;
1260 } else {
1261 *id_p = cache[idnum+1]; // fetch jmethodID (if any)
1262 }
1263 }
1264
1265
1266 // Lookup a jmethodID, NULL if not found. Do no blocking, no allocations, no handles
1267 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
1268 size_t idnum = (size_t)method->method_idnum();
1269 jmethodID* jmeths = methods_jmethod_ids_acquire();
1270 size_t length; // length assigned as debugging crumb
1271 jmethodID id = NULL;
1272 if (jmeths != NULL && // If there is a cache
1273 (length = (size_t)jmeths[0]) > idnum) { // and if it is long enough,
1274 id = jmeths[idnum+1]; // Look up the id (may be NULL)
1275 }
1276 return id;
1277 }
1278
1279
1280 // Cache an itable index
1281 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
1282 int* indices = methods_cached_itable_indices_acquire();
1283 int* to_dealloc_indices = NULL;
1284
1285 // We use a double-check locking idiom here because this cache is
1286 // performance sensitive. In the normal system, this cache only
1287 // transitions from NULL to non-NULL which is safe because we use
1288 // release_set_methods_cached_itable_indices() to advertise the
1289 // new cache. A partially constructed cache should never be seen
1290 // by a racing thread. Cache reads and writes proceed without a
1291 // lock, but creation of the cache itself requires no leaks so a
1292 // lock is generally acquired in that case.
1293 //
1294 // If the RedefineClasses() API has been used, then this cache can
1295 // grow and we'll have transitions from non-NULL to bigger non-NULL.
1296 // Cache creation requires no leaks and we require safety between all
1297 // cache accesses and freeing of the old cache so a lock is generally
1298 // acquired when the RedefineClasses() API has been used.
1299
1300 if (indices == NULL || idnum_can_increment()) {
1301 // we need a cache or the cache can grow
1302 MutexLocker ml(JNICachedItableIndex_lock);
1303 // reacquire the cache to see if another thread already did the work
1304 indices = methods_cached_itable_indices_acquire();
1305 size_t length = 0;
1306 // cache size is stored in element[0], other elements offset by one
1307 if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
1308 size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1309 int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);
1310 new_indices[0] = (int)size;
1311 // copy any existing entries
1312 size_t i;
1313 for (i = 0; i < length; i++) {
1314 new_indices[i+1] = indices[i+1];
1315 }
1316 // Set all the rest to -1
1317 for (i = length; i < size; i++) {
1318 new_indices[i+1] = -1;
1319 }
1320 if (indices != NULL) {
1321 // We have an old cache to delete so save it for after we
1322 // drop the lock.
1323 to_dealloc_indices = indices;
1324 }
1325 release_set_methods_cached_itable_indices(indices = new_indices);
1326 }
1327
1328 if (idnum_can_increment()) {
1329 // this cache can grow so we have to write to it safely
1330 indices[idnum+1] = index;
1331 }
1332 } else {
1333 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
1334 }
1335
1336 if (!idnum_can_increment()) {
1337 // The cache cannot grow and this JNI itable index value does not
1338 // have to be unique like a jmethodID. If there is a race to set it,
1339 // it doesn't matter.
1340 indices[idnum+1] = index;
1341 }
1342
1343 if (to_dealloc_indices != NULL) {
1344 // we allocated a new cache so free the old one
1345 FreeHeap(to_dealloc_indices);
1346 }
1347 }
1348
1349
1350 // Retrieve a cached itable index
1351 int instanceKlass::cached_itable_index(size_t idnum) {
1352 int* indices = methods_cached_itable_indices_acquire();
1353 if (indices != NULL && ((size_t)indices[0]) > idnum) {
1354 // indices exist and are long enough, retrieve possible cached
1355 return indices[idnum+1];
1356 }
1357 return -1;
1358 }
1359
1360
1361 //
1362 // nmethodBucket is used to record dependent nmethods for
1363 // deoptimization. nmethod dependencies are actually <klass, method>
1364 // pairs but we really only care about the klass part for purposes of
1365 // finding nmethods which might need to be deoptimized. Instead of
1366 // recording the method, a count of how many times a particular nmethod
1367 // was recorded is kept. This ensures that any recording errors are
1368 // noticed since an nmethod should be removed as many times are it's
1369 // added.
1370 //
1371 class nmethodBucket {
1372 private:
1373 nmethod* _nmethod;
1374 int _count;
1375 nmethodBucket* _next;
1376
1377 public:
1378 nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1379 _nmethod = nmethod;
1380 _next = next;
1381 _count = 1;
1382 }
1383 int count() { return _count; }
1384 int increment() { _count += 1; return _count; }
1385 int decrement() { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
1386 nmethodBucket* next() { return _next; }
1387 void set_next(nmethodBucket* b) { _next = b; }
1388 nmethod* get_nmethod() { return _nmethod; }
1389 };
1390
1391
1392 //
1393 // Walk the list of dependent nmethods searching for nmethods which
1394 // are dependent on the klassOop that was passed in and mark them for
1395 // deoptimization. Returns the number of nmethods found.
1396 //
1397 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
1398 assert_locked_or_safepoint(CodeCache_lock);
1399 int found = 0;
1400 nmethodBucket* b = _dependencies;
1401 while (b != NULL) {
1402 nmethod* nm = b->get_nmethod();
1403 // since dependencies aren't removed until an nmethod becomes a zombie,
1404 // the dependency list may contain nmethods which aren't alive.
1405 if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
1406 if (TraceDependencies) {
1407 ResourceMark rm;
1408 tty->print_cr("Marked for deoptimization");
1409 tty->print_cr(" context = %s", this->external_name());
1410 changes.print();
1411 nm->print();
1412 nm->print_dependencies();
1413 }
1414 nm->mark_for_deoptimization();
1415 found++;
1416 }
1417 b = b->next();
1418 }
1419 return found;
1420 }
1421
1422
1423 //
1424 // Add an nmethodBucket to the list of dependencies for this nmethod.
1425 // It's possible that an nmethod has multiple dependencies on this klass
1426 // so a count is kept for each bucket to guarantee that creation and
1427 // deletion of dependencies is consistent.
1428 //
1429 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
1430 assert_locked_or_safepoint(CodeCache_lock);
1431 nmethodBucket* b = _dependencies;
1432 nmethodBucket* last = NULL;
1433 while (b != NULL) {
1434 if (nm == b->get_nmethod()) {
1435 b->increment();
1436 return;
1437 }
1438 b = b->next();
1439 }
1440 _dependencies = new nmethodBucket(nm, _dependencies);
1441 }
1442
1443
1444 //
1445 // Decrement count of the nmethod in the dependency list and remove
1446 // the bucket competely when the count goes to 0. This method must
1447 // find a corresponding bucket otherwise there's a bug in the
1448 // recording of dependecies.
1449 //
1450 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
1451 assert_locked_or_safepoint(CodeCache_lock);
1452 nmethodBucket* b = _dependencies;
1453 nmethodBucket* last = NULL;
1454 while (b != NULL) {
1455 if (nm == b->get_nmethod()) {
1456 if (b->decrement() == 0) {
1457 if (last == NULL) {
1458 _dependencies = b->next();
1459 } else {
1460 last->set_next(b->next());
1461 }
1462 delete b;
1463 }
1464 return;
1465 }
1466 last = b;
1467 b = b->next();
1468 }
1469 #ifdef ASSERT
1470 tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
1471 nm->print();
1472 #endif // ASSERT
1473 ShouldNotReachHere();
1474 }
1475
1476
1477 #ifndef PRODUCT
1478 void instanceKlass::print_dependent_nmethods(bool verbose) {
1479 nmethodBucket* b = _dependencies;
1480 int idx = 0;
1481 while (b != NULL) {
1482 nmethod* nm = b->get_nmethod();
1483 tty->print("[%d] count=%d { ", idx++, b->count());
1484 if (!verbose) {
1485 nm->print_on(tty, "nmethod");
1486 tty->print_cr(" } ");
1487 } else {
1488 nm->print();
1489 nm->print_dependencies();
1490 tty->print_cr("--- } ");
1491 }
1492 b = b->next();
1493 }
1494 }
1495
1496
1497 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
1498 nmethodBucket* b = _dependencies;
1499 while (b != NULL) {
1500 if (nm == b->get_nmethod()) {
1501 return true;
1502 }
1503 b = b->next();
1504 }
1505 return false;
1506 }
1507 #endif //PRODUCT
1508
1509
1510 #ifdef ASSERT
1511 template <class T> void assert_is_in(T *p) {
1512 T heap_oop = oopDesc::load_heap_oop(p);
1513 if (!oopDesc::is_null(heap_oop)) {
1514 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1515 assert(Universe::heap()->is_in(o), "should be in heap");
1516 }
1517 }
1518 template <class T> void assert_is_in_closed_subset(T *p) {
1519 T heap_oop = oopDesc::load_heap_oop(p);
1520 if (!oopDesc::is_null(heap_oop)) {
1521 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1522 assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
1523 }
1524 }
1525 template <class T> void assert_is_in_reserved(T *p) {
1526 T heap_oop = oopDesc::load_heap_oop(p);
1527 if (!oopDesc::is_null(heap_oop)) {
1528 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1529 assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
1530 }
1531 }
1532 template <class T> void assert_nothing(T *p) {}
1533
1534 #else
1535 template <class T> void assert_is_in(T *p) {}
1536 template <class T> void assert_is_in_closed_subset(T *p) {}
1537 template <class T> void assert_is_in_reserved(T *p) {}
1538 template <class T> void assert_nothing(T *p) {}
1539 #endif // ASSERT
1540
1541 //
1542 // Macros that iterate over areas of oops which are specialized on type of
1543 // oop pointer either narrow or wide, depending on UseCompressedOops
1544 //
1545 // Parameters are:
1546 // T - type of oop to point to (either oop or narrowOop)
1547 // start_p - starting pointer for region to iterate over
1548 // count - number of oops or narrowOops to iterate over
1549 // do_oop - action to perform on each oop (it's arbitrary C code which
1550 // makes it more efficient to put in a macro rather than making
1551 // it a template function)
1552 // assert_fn - assert function which is template function because performance
1553 // doesn't matter when enabled.
1554 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
1555 T, start_p, count, do_oop, \
1556 assert_fn) \
1557 { \
1558 T* p = (T*)(start_p); \
1559 T* const end = p + (count); \
1560 while (p < end) { \
1561 (assert_fn)(p); \
1562 do_oop; \
1563 ++p; \
1564 } \
1565 }
1566
1567 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
1568 T, start_p, count, do_oop, \
1569 assert_fn) \
1570 { \
1571 T* const start = (T*)(start_p); \
1572 T* p = start + (count); \
1573 while (start < p) { \
1574 --p; \
1575 (assert_fn)(p); \
1576 do_oop; \
1577 } \
1578 }
1579
1580 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
1581 T, start_p, count, low, high, \
1582 do_oop, assert_fn) \
1583 { \
1584 T* const l = (T*)(low); \
1585 T* const h = (T*)(high); \
1586 assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
1587 mask_bits((intptr_t)h, sizeof(T)-1) == 0, \
1588 "bounded region must be properly aligned"); \
1589 T* p = (T*)(start_p); \
1590 T* end = p + (count); \
1591 if (p < l) p = l; \
1592 if (end > h) end = h; \
1593 while (p < end) { \
1594 (assert_fn)(p); \
1595 do_oop; \
1596 ++p; \
1597 } \
1598 }
1599
1600
1601 // The following macros call specialized macros, passing either oop or
1602 // narrowOop as the specialization type. These test the UseCompressedOops
1603 // flag.
1604 #define InstanceKlass_OOP_ITERATE(start_p, count, \
1605 do_oop, assert_fn) \
1606 { \
1607 if (UseCompressedOops) { \
1608 InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
1609 start_p, count, \
1610 do_oop, assert_fn) \
1611 } else { \
1612 InstanceKlass_SPECIALIZED_OOP_ITERATE(oop, \
1613 start_p, count, \
1614 do_oop, assert_fn) \
1615 } \
1616 }
1617
1618 #define InstanceKlass_BOUNDED_OOP_ITERATE(start_p, count, low, high, \
1619 do_oop, assert_fn) \
1620 { \
1621 if (UseCompressedOops) { \
1622 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
1623 start_p, count, \
1624 low, high, \
1625 do_oop, assert_fn) \
1626 } else { \
1627 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop, \
1628 start_p, count, \
1629 low, high, \
1630 do_oop, assert_fn) \
1631 } \
1632 }
1633
1634 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn) \
1635 { \
1636 /* Compute oopmap block range. The common case \
1637 is nonstatic_oop_map_size == 1. */ \
1638 OopMapBlock* map = start_of_nonstatic_oop_maps(); \
1639 OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \
1640 if (UseCompressedOops) { \
1641 while (map < end_map) { \
1642 InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
1643 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1644 do_oop, assert_fn) \
1645 ++map; \
1646 } \
1647 } else { \
1648 while (map < end_map) { \
1649 InstanceKlass_SPECIALIZED_OOP_ITERATE(oop, \
1650 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1651 do_oop, assert_fn) \
1652 ++map; \
1653 } \
1654 } \
1655 }
1656
1657 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn) \
1658 { \
1659 OopMapBlock* const start_map = start_of_nonstatic_oop_maps(); \
1660 OopMapBlock* map = start_map + nonstatic_oop_map_count(); \
1661 if (UseCompressedOops) { \
1662 while (start_map < map) { \
1663 --map; \
1664 InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop, \
1665 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1666 do_oop, assert_fn) \
1667 } \
1668 } else { \
1669 while (start_map < map) { \
1670 --map; \
1671 InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop, \
1672 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1673 do_oop, assert_fn) \
1674 } \
1675 } \
1676 }
1677
1678 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop, \
1679 assert_fn) \
1680 { \
1681 /* Compute oopmap block range. The common case is \
1682 nonstatic_oop_map_size == 1, so we accept the \
1683 usually non-existent extra overhead of examining \
1684 all the maps. */ \
1685 OopMapBlock* map = start_of_nonstatic_oop_maps(); \
1686 OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \
1687 if (UseCompressedOops) { \
1688 while (map < end_map) { \
1689 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
1690 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1691 low, high, \
1692 do_oop, assert_fn) \
1693 ++map; \
1694 } \
1695 } else { \
1696 while (map < end_map) { \
1697 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop, \
1698 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1699 low, high, \
1700 do_oop, assert_fn) \
1701 ++map; \
1702 } \
1703 } \
1704 }
1705
1706 void instanceKlass::follow_static_fields() {
1707 InstanceKlass_OOP_ITERATE( \
1708 start_of_static_fields(), static_oop_field_size(), \
1709 MarkSweep::mark_and_push(p), \
1710 assert_is_in_closed_subset)
1711 }
1712
1713 #ifndef SERIALGC
1714 void instanceKlass::follow_static_fields(ParCompactionManager* cm) {
1715 InstanceKlass_OOP_ITERATE( \
1716 start_of_static_fields(), static_oop_field_size(), \
1717 PSParallelCompact::mark_and_push(cm, p), \
1718 assert_is_in)
1719 }
1720 #endif // SERIALGC
1721
1722 void instanceKlass::adjust_static_fields() {
1723 InstanceKlass_OOP_ITERATE( \
1724 start_of_static_fields(), static_oop_field_size(), \
1725 MarkSweep::adjust_pointer(p), \
1726 assert_nothing)
1727 }
1728
1729 #ifndef SERIALGC
1730 void instanceKlass::update_static_fields() {
1731 InstanceKlass_OOP_ITERATE( \
1732 start_of_static_fields(), static_oop_field_size(), \
1733 PSParallelCompact::adjust_pointer(p), \
1734 assert_nothing)
1735 }
1736
1737 void instanceKlass::update_static_fields(HeapWord* beg_addr, HeapWord* end_addr) {
1738 InstanceKlass_BOUNDED_OOP_ITERATE( \
1739 start_of_static_fields(), static_oop_field_size(), \
1740 beg_addr, end_addr, \
1741 PSParallelCompact::adjust_pointer(p), \
1742 assert_nothing )
1743 }
1744 #endif // SERIALGC
1745
1746 void instanceKlass::oop_follow_contents(oop obj) {
1747 assert(obj != NULL, "can't follow the content of NULL object");
1748 obj->follow_header();
1749 InstanceKlass_OOP_MAP_ITERATE( \
1750 obj, \
1751 MarkSweep::mark_and_push(p), \
1752 assert_is_in_closed_subset)
1753 }
1754
1755 #ifndef SERIALGC
1756 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,
1757 oop obj) {
1758 assert(obj != NULL, "can't follow the content of NULL object");
1759 obj->follow_header(cm);
1760 InstanceKlass_OOP_MAP_ITERATE( \
1761 obj, \
1762 PSParallelCompact::mark_and_push(cm, p), \
1763 assert_is_in)
1764 }
1765 #endif // SERIALGC
1766
1767 // closure's do_header() method dicates whether the given closure should be
1768 // applied to the klass ptr in the object header.
1769
1770 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
1771 \
1772 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
1773 SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1774 /* header */ \
1775 if (closure->do_header()) { \
1776 obj->oop_iterate_header(closure); \
1777 } \
1778 InstanceKlass_OOP_MAP_ITERATE( \
1779 obj, \
1780 SpecializationStats:: \
1781 record_do_oop_call##nv_suffix(SpecializationStats::ik); \
1782 (closure)->do_oop##nv_suffix(p), \
1783 assert_is_in_closed_subset) \
1784 return size_helper(); \
1785 }
1786
1787 #ifndef SERIALGC
1788 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
1789 \
1790 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj, \
1791 OopClosureType* closure) { \
1792 SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
1793 /* header */ \
1794 if (closure->do_header()) { \
1795 obj->oop_iterate_header(closure); \
1796 } \
1797 /* instance variables */ \
1798 InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
1799 obj, \
1800 SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
1801 (closure)->do_oop##nv_suffix(p), \
1802 assert_is_in_closed_subset) \
1803 return size_helper(); \
1804 }
1805 #endif // !SERIALGC
1806
1807 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
1808 \
1809 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj, \
1810 OopClosureType* closure, \
1811 MemRegion mr) { \
1812 SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1813 if (closure->do_header()) { \
1814 obj->oop_iterate_header(closure, mr); \
1815 } \
1816 InstanceKlass_BOUNDED_OOP_MAP_ITERATE( \
1817 obj, mr.start(), mr.end(), \
1818 (closure)->do_oop##nv_suffix(p), \
1819 assert_is_in_closed_subset) \
1820 return size_helper(); \
1821 }
1822
1823 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1824 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1825 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1826 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1827 #ifndef SERIALGC
1828 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1829 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1830 #endif // !SERIALGC
1831
1832 void instanceKlass::iterate_static_fields(OopClosure* closure) {
1833 InstanceKlass_OOP_ITERATE( \
1834 start_of_static_fields(), static_oop_field_size(), \
1835 closure->do_oop(p), \
1836 assert_is_in_reserved)
1837 }
1838
1839 void instanceKlass::iterate_static_fields(OopClosure* closure,
1840 MemRegion mr) {
1841 InstanceKlass_BOUNDED_OOP_ITERATE( \
1842 start_of_static_fields(), static_oop_field_size(), \
1843 mr.start(), mr.end(), \
1844 (closure)->do_oop_v(p), \
1845 assert_is_in_closed_subset)
1846 }
1847
1848 int instanceKlass::oop_adjust_pointers(oop obj) {
1849 int size = size_helper();
1850 InstanceKlass_OOP_MAP_ITERATE( \
1851 obj, \
1852 MarkSweep::adjust_pointer(p), \
1853 assert_is_in)
1854 obj->adjust_header();
1855 return size;
1856 }
1857
1858 #ifndef SERIALGC
1859 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
1860 InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
1861 obj, \
1862 if (PSScavenge::should_scavenge(p)) { \
1863 pm->claim_or_forward_depth(p); \
1864 }, \
1865 assert_nothing )
1866 }
1867
1868 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
1869 InstanceKlass_OOP_MAP_ITERATE( \
1870 obj, \
1871 PSParallelCompact::adjust_pointer(p), \
1872 assert_nothing)
1873 return size_helper();
1874 }
1875
1876 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj,
1877 HeapWord* beg_addr, HeapWord* end_addr) {
1878 InstanceKlass_BOUNDED_OOP_MAP_ITERATE( \
1879 obj, beg_addr, end_addr, \
1880 PSParallelCompact::adjust_pointer(p), \
1881 assert_nothing)
1882 return size_helper();
1883 }
1884
1885 void instanceKlass::push_static_fields(PSPromotionManager* pm) {
1886 InstanceKlass_OOP_ITERATE( \
1887 start_of_static_fields(), static_oop_field_size(), \
1888 if (PSScavenge::should_scavenge(p)) { \
1889 pm->claim_or_forward_depth(p); \
1890 }, \
1891 assert_nothing )
1892 }
1893
1894 void instanceKlass::copy_static_fields(ParCompactionManager* cm) {
1895 InstanceKlass_OOP_ITERATE( \
1896 start_of_static_fields(), static_oop_field_size(), \
1897 PSParallelCompact::adjust_pointer(p), \
1898 assert_is_in)
1899 }
1900 #endif // SERIALGC
1901
1902 // This klass is alive but the implementor link is not followed/updated.
1903 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
1904
1905 void instanceKlass::follow_weak_klass_links(
1906 BoolObjectClosure* is_alive, OopClosure* keep_alive) {
1907 assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
1908 if (ClassUnloading) {
1909 for (int i = 0; i < implementors_limit; i++) {
1910 klassOop impl = _implementors[i];
1911 if (impl == NULL) break; // no more in the list
1912 if (!is_alive->do_object_b(impl)) {
1913 // remove this guy from the list by overwriting him with the tail
1914 int lasti = --_nof_implementors;
1915 assert(lasti >= i && lasti < implementors_limit, "just checking");
1916 _implementors[i] = _implementors[lasti];
1917 _implementors[lasti] = NULL;
1918 --i; // rerun the loop at this index
1919 }
1920 }
1921 } else {
1922 for (int i = 0; i < implementors_limit; i++) {
1923 keep_alive->do_oop(&adr_implementors()[i]);
1924 }
1925 }
1926 Klass::follow_weak_klass_links(is_alive, keep_alive);
1927 }
1928
1929 void instanceKlass::remove_unshareable_info() {
1930 Klass::remove_unshareable_info();
1931 init_implementor();
1932 }
1933
1934 static void clear_all_breakpoints(methodOop m) {
1935 m->clear_all_breakpoints();
1936 }
1937
1938 void instanceKlass::release_C_heap_structures() {
1939 // Deallocate oop map cache
1940 if (_oop_map_cache != NULL) {
1941 delete _oop_map_cache;
1942 _oop_map_cache = NULL;
1943 }
1944
1945 // Deallocate JNI identifiers for jfieldIDs
1946 JNIid::deallocate(jni_ids());
1947 set_jni_ids(NULL);
1948
1949 jmethodID* jmeths = methods_jmethod_ids_acquire();
1950 if (jmeths != (jmethodID*)NULL) {
1951 release_set_methods_jmethod_ids(NULL);
1952 FreeHeap(jmeths);
1953 }
1954
1955 int* indices = methods_cached_itable_indices_acquire();
1956 if (indices != (int*)NULL) {
1957 release_set_methods_cached_itable_indices(NULL);
1958 FreeHeap(indices);
1959 }
1960
1961 // release dependencies
1962 nmethodBucket* b = _dependencies;
1963 _dependencies = NULL;
1964 while (b != NULL) {
1965 nmethodBucket* next = b->next();
1966 delete b;
1967 b = next;
1968 }
1969
1970 // Deallocate breakpoint records
1971 if (breakpoints() != 0x0) {
1972 methods_do(clear_all_breakpoints);
1973 assert(breakpoints() == 0x0, "should have cleared breakpoints");
1974 }
1975
1976 // deallocate information about previous versions
1977 if (_previous_versions != NULL) {
1978 for (int i = _previous_versions->length() - 1; i >= 0; i--) {
1979 PreviousVersionNode * pv_node = _previous_versions->at(i);
1980 delete pv_node;
1981 }
1982 delete _previous_versions;
1983 _previous_versions = NULL;
1984 }
1985
1986 // deallocate the cached class file
1987 if (_cached_class_file_bytes != NULL) {
1988 os::free(_cached_class_file_bytes);
1989 _cached_class_file_bytes = NULL;
1990 _cached_class_file_len = 0;
1991 }
1992 }
1993
1994 const char* instanceKlass::signature_name() const {
1995 const char* src = (const char*) (name()->as_C_string());
1996 const int src_length = (int)strlen(src);
1997 char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
1998 int src_index = 0;
1999 int dest_index = 0;
2000 dest[dest_index++] = 'L';
2001 while (src_index < src_length) {
2002 dest[dest_index++] = src[src_index++];
2003 }
2004 dest[dest_index++] = ';';
2005 dest[dest_index] = '\0';
2006 return dest;
2007 }
2008
2009 // different verisons of is_same_class_package
2010 bool instanceKlass::is_same_class_package(klassOop class2) {
2011 klassOop class1 = as_klassOop();
2012 oop classloader1 = instanceKlass::cast(class1)->class_loader();
2013 symbolOop classname1 = Klass::cast(class1)->name();
2014
2015 if (Klass::cast(class2)->oop_is_objArray()) {
2016 class2 = objArrayKlass::cast(class2)->bottom_klass();
2017 }
2018 oop classloader2;
2019 if (Klass::cast(class2)->oop_is_instance()) {
2020 classloader2 = instanceKlass::cast(class2)->class_loader();
2021 } else {
2022 assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
2023 classloader2 = NULL;
2024 }
2025 symbolOop classname2 = Klass::cast(class2)->name();
2026
2027 return instanceKlass::is_same_class_package(classloader1, classname1,
2028 classloader2, classname2);
2029 }
2030
2031 bool instanceKlass::is_same_class_package(oop classloader2, symbolOop classname2) {
2032 klassOop class1 = as_klassOop();
2033 oop classloader1 = instanceKlass::cast(class1)->class_loader();
2034 symbolOop classname1 = Klass::cast(class1)->name();
2035
2036 return instanceKlass::is_same_class_package(classloader1, classname1,
2037 classloader2, classname2);
2038 }
2039
2040 // return true if two classes are in the same package, classloader
2041 // and classname information is enough to determine a class's package
2042 bool instanceKlass::is_same_class_package(oop class_loader1, symbolOop class_name1,
2043 oop class_loader2, symbolOop class_name2) {
2044 if (class_loader1 != class_loader2) {
2045 return false;
2046 } else if (class_name1 == class_name2) {
2047 return true; // skip painful bytewise comparison
2048 } else {
2049 ResourceMark rm;
2050
2051 // The symbolOop's are in UTF8 encoding. Since we only need to check explicitly
2052 // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
2053 // Otherwise, we just compare jbyte values between the strings.
2054 jbyte *name1 = class_name1->base();
2055 jbyte *name2 = class_name2->base();
2056
2057 jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
2058 jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
2059
2060 if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
2061 // One of the two doesn't have a package. Only return true
2062 // if the other one also doesn't have a package.
2063 return last_slash1 == last_slash2;
2064 } else {
2065 // Skip over '['s
2066 if (*name1 == '[') {
2067 do {
2068 name1++;
2069 } while (*name1 == '[');
2070 if (*name1 != 'L') {
2071 // Something is terribly wrong. Shouldn't be here.
2072 return false;
2073 }
2074 }
2075 if (*name2 == '[') {
2076 do {
2077 name2++;
2078 } while (*name2 == '[');
2079 if (*name2 != 'L') {
2080 // Something is terribly wrong. Shouldn't be here.
2081 return false;
2082 }
2083 }
2084
2085 // Check that package part is identical
2086 int length1 = last_slash1 - name1;
2087 int length2 = last_slash2 - name2;
2088
2089 return UTF8::equal(name1, length1, name2, length2);
2090 }
2091 }
2092 }
2093
2094 // Returns true iff super_method can be overridden by a method in targetclassname
2095 // See JSL 3rd edition 8.4.6.1
2096 // Assumes name-signature match
2097 // "this" is instanceKlass of super_method which must exist
2098 // note that the instanceKlass of the method in the targetclassname has not always been created yet
2099 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, symbolHandle targetclassname, TRAPS) {
2100 // Private methods can not be overridden
2101 if (super_method->is_private()) {
2102 return false;
2103 }
2104 // If super method is accessible, then override
2105 if ((super_method->is_protected()) ||
2106 (super_method->is_public())) {
2107 return true;
2108 }
2109 // Package-private methods are not inherited outside of package
2110 assert(super_method->is_package_private(), "must be package private");
2111 return(is_same_class_package(targetclassloader(), targetclassname()));
2112 }
2113
2114 /* defined for now in jvm.cpp, for historical reasons *--
2115 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
2116 symbolOop& simple_name_result, TRAPS) {
2117 ...
2118 }
2119 */
2120
2121 // tell if two classes have the same enclosing class (at package level)
2122 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
2123 klassOop class2_oop, TRAPS) {
2124 if (class2_oop == class1->as_klassOop()) return true;
2125 if (!Klass::cast(class2_oop)->oop_is_instance()) return false;
2126 instanceKlassHandle class2(THREAD, class2_oop);
2127
2128 // must be in same package before we try anything else
2129 if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
2130 return false;
2131
2132 // As long as there is an outer1.getEnclosingClass,
2133 // shift the search outward.
2134 instanceKlassHandle outer1 = class1;
2135 for (;;) {
2136 // As we walk along, look for equalities between outer1 and class2.
2137 // Eventually, the walks will terminate as outer1 stops
2138 // at the top-level class around the original class.
2139 bool ignore_inner_is_member;
2140 klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
2141 CHECK_false);
2142 if (next == NULL) break;
2143 if (next == class2()) return true;
2144 outer1 = instanceKlassHandle(THREAD, next);
2145 }
2146
2147 // Now do the same for class2.
2148 instanceKlassHandle outer2 = class2;
2149 for (;;) {
2150 bool ignore_inner_is_member;
2151 klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2152 CHECK_false);
2153 if (next == NULL) break;
2154 // Might as well check the new outer against all available values.
2155 if (next == class1()) return true;
2156 if (next == outer1()) return true;
2157 outer2 = instanceKlassHandle(THREAD, next);
2158 }
2159
2160 // If by this point we have not found an equality between the
2161 // two classes, we know they are in separate package members.
2162 return false;
2163 }
2164
2165
2166 jint instanceKlass::compute_modifier_flags(TRAPS) const {
2167 klassOop k = as_klassOop();
2168 jint access = access_flags().as_int();
2169
2170 // But check if it happens to be member class.
2171 typeArrayOop inner_class_list = inner_classes();
2172 int length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
2173 assert (length % instanceKlass::inner_class_next_offset == 0, "just checking");
2174 if (length > 0) {
2175 typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
2176 instanceKlassHandle ik(THREAD, k);
2177 for (int i = 0; i < length; i += instanceKlass::inner_class_next_offset) {
2178 int ioff = inner_class_list_h->ushort_at(
2179 i + instanceKlass::inner_class_inner_class_info_offset);
2180
2181 // Inner class attribute can be zero, skip it.
2182 // Strange but true: JVM spec. allows null inner class refs.
2183 if (ioff == 0) continue;
2184
2185 // only look at classes that are already loaded
2186 // since we are looking for the flags for our self.
2187 symbolOop inner_name = ik->constants()->klass_name_at(ioff);
2188 if ((ik->name() == inner_name)) {
2189 // This is really a member class.
2190 access = inner_class_list_h->ushort_at(i + instanceKlass::inner_class_access_flags_offset);
2191 break;
2192 }
2193 }
2194 }
2195 // Remember to strip ACC_SUPER bit
2196 return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2197 }
2198
2199 jint instanceKlass::jvmti_class_status() const {
2200 jint result = 0;
2201
2202 if (is_linked()) {
2203 result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2204 }
2205
2206 if (is_initialized()) {
2207 assert(is_linked(), "Class status is not consistent");
2208 result |= JVMTI_CLASS_STATUS_INITIALIZED;
2209 }
2210 if (is_in_error_state()) {
2211 result |= JVMTI_CLASS_STATUS_ERROR;
2212 }
2213 return result;
2214 }
2215
2216 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
2217 itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2218 int method_table_offset_in_words = ioe->offset()/wordSize;
2219 int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2220 / itableOffsetEntry::size();
2221
2222 for (int cnt = 0 ; ; cnt ++, ioe ++) {
2223 // If the interface isn't implemented by the receiver class,
2224 // the VM should throw IncompatibleClassChangeError.
2225 if (cnt >= nof_interfaces) {
2226 THROW_OOP_0(vmSymbols::java_lang_IncompatibleClassChangeError());
2227 }
2228
2229 klassOop ik = ioe->interface_klass();
2230 if (ik == holder) break;
2231 }
2232
2233 itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
2234 methodOop m = ime[index].method();
2235 if (m == NULL) {
2236 THROW_OOP_0(vmSymbols::java_lang_AbstractMethodError());
2237 }
2238 return m;
2239 }
2240
2241 // On-stack replacement stuff
2242 void instanceKlass::add_osr_nmethod(nmethod* n) {
2243 // only one compilation can be active
2244 NEEDS_CLEANUP
2245 // This is a short non-blocking critical region, so the no safepoint check is ok.
2246 OsrList_lock->lock_without_safepoint_check();
2247 assert(n->is_osr_method(), "wrong kind of nmethod");
2248 n->set_osr_link(osr_nmethods_head());
2249 set_osr_nmethods_head(n);
2250 // Raise the highest osr level if necessary
2251 if (TieredCompilation) {
2252 methodOop m = n->method();
2253 m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2254 }
2255 // Remember to unlock again
2256 OsrList_lock->unlock();
2257
2258 // Get rid of the osr methods for the same bci that have lower levels.
2259 if (TieredCompilation) {
2260 for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2261 nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2262 if (inv != NULL && inv->is_in_use()) {
2263 inv->make_not_entrant();
2264 }
2265 }
2266 }
2267 }
2268
2269
2270 void instanceKlass::remove_osr_nmethod(nmethod* n) {
2271 // This is a short non-blocking critical region, so the no safepoint check is ok.
2272 OsrList_lock->lock_without_safepoint_check();
2273 assert(n->is_osr_method(), "wrong kind of nmethod");
2274 nmethod* last = NULL;
2275 nmethod* cur = osr_nmethods_head();
2276 int max_level = CompLevel_none; // Find the max comp level excluding n
2277 methodOop m = n->method();
2278 // Search for match
2279 while(cur != NULL && cur != n) {
2280 if (TieredCompilation) {
2281 // Find max level before n
2282 max_level = MAX2(max_level, cur->comp_level());
2283 }
2284 last = cur;
2285 cur = cur->osr_link();
2286 }
2287 nmethod* next = NULL;
2288 if (cur == n) {
2289 next = cur->osr_link();
2290 if (last == NULL) {
2291 // Remove first element
2292 set_osr_nmethods_head(next);
2293 } else {
2294 last->set_osr_link(next);
2295 }
2296 }
2297 n->set_osr_link(NULL);
2298 if (TieredCompilation) {
2299 cur = next;
2300 while (cur != NULL) {
2301 // Find max level after n
2302 max_level = MAX2(max_level, cur->comp_level());
2303 cur = cur->osr_link();
2304 }
2305 m->set_highest_osr_comp_level(max_level);
2306 }
2307 // Remember to unlock again
2308 OsrList_lock->unlock();
2309 }
2310
2311 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
2312 // This is a short non-blocking critical region, so the no safepoint check is ok.
2313 OsrList_lock->lock_without_safepoint_check();
2314 nmethod* osr = osr_nmethods_head();
2315 nmethod* best = NULL;
2316 while (osr != NULL) {
2317 assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2318 // There can be a time when a c1 osr method exists but we are waiting
2319 // for a c2 version. When c2 completes its osr nmethod we will trash
2320 // the c1 version and only be able to find the c2 version. However
2321 // while we overflow in the c1 code at back branches we don't want to
2322 // try and switch to the same code as we are already running
2323
2324 if (osr->method() == m &&
2325 (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2326 if (match_level) {
2327 if (osr->comp_level() == comp_level) {
2328 // Found a match - return it.
2329 OsrList_lock->unlock();
2330 return osr;
2331 }
2332 } else {
2333 if (best == NULL || (osr->comp_level() > best->comp_level())) {
2334 if (osr->comp_level() == CompLevel_highest_tier) {
2335 // Found the best possible - return it.
2336 OsrList_lock->unlock();
2337 return osr;
2338 }
2339 best = osr;
2340 }
2341 }
2342 }
2343 osr = osr->osr_link();
2344 }
2345 OsrList_lock->unlock();
2346 if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2347 return best;
2348 }
2349 return NULL;
2350 }
2351
2352 // -----------------------------------------------------------------------------------------------------
2353 #ifndef PRODUCT
2354
2355 // Printing
2356
2357 #define BULLET " - "
2358
2359 void FieldPrinter::do_field(fieldDescriptor* fd) {
2360 _st->print(BULLET);
2361 if (fd->is_static() || (_obj == NULL)) {
2362 fd->print_on(_st);
2363 _st->cr();
2364 } else {
2365 fd->print_on_for(_st, _obj);
2366 _st->cr();
2367 }
2368 }
2369
2370
2371 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
2372 Klass::oop_print_on(obj, st);
2373
2374 if (as_klassOop() == SystemDictionary::String_klass()) {
2375 typeArrayOop value = java_lang_String::value(obj);
2376 juint offset = java_lang_String::offset(obj);
2377 juint length = java_lang_String::length(obj);
2378 if (value != NULL &&
2379 value->is_typeArray() &&
2380 offset <= (juint) value->length() &&
2381 offset + length <= (juint) value->length()) {
2382 st->print(BULLET"string: ");
2383 Handle h_obj(obj);
2384 java_lang_String::print(h_obj, st);
2385 st->cr();
2386 if (!WizardMode) return; // that is enough
2387 }
2388 }
2389
2390 st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2391 FieldPrinter print_nonstatic_field(st, obj);
2392 do_nonstatic_fields(&print_nonstatic_field);
2393
2394 if (as_klassOop() == SystemDictionary::Class_klass()) {
2395 st->print(BULLET"signature: ");
2396 java_lang_Class::print_signature(obj, st);
2397 st->cr();
2398 klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
2399 st->print(BULLET"fake entry for mirror: ");
2400 mirrored_klass->print_value_on(st);
2401 st->cr();
2402 st->print(BULLET"fake entry resolved_constructor: ");
2403 methodOop ctor = java_lang_Class::resolved_constructor(obj);
2404 ctor->print_value_on(st);
2405 klassOop array_klass = java_lang_Class::array_klass(obj);
2406 st->cr();
2407 st->print(BULLET"fake entry for array: ");
2408 array_klass->print_value_on(st);
2409 st->cr();
2410 } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2411 st->print(BULLET"signature: ");
2412 java_dyn_MethodType::print_signature(obj, st);
2413 st->cr();
2414 }
2415 }
2416
2417 #endif //PRODUCT
2418
2419 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
2420 st->print("a ");
2421 name()->print_value_on(st);
2422 obj->print_address_on(st);
2423 if (as_klassOop() == SystemDictionary::String_klass()
2424 && java_lang_String::value(obj) != NULL) {
2425 ResourceMark rm;
2426 int len = java_lang_String::length(obj);
2427 int plen = (len < 24 ? len : 12);
2428 char* str = java_lang_String::as_utf8_string(obj, 0, plen);
2429 st->print(" = \"%s\"", str);
2430 if (len > plen)
2431 st->print("...[%d]", len);
2432 } else if (as_klassOop() == SystemDictionary::Class_klass()) {
2433 klassOop k = java_lang_Class::as_klassOop(obj);
2434 st->print(" = ");
2435 if (k != NULL) {
2436 k->print_value_on(st);
2437 } else {
2438 const char* tname = type2name(java_lang_Class::primitive_type(obj));
2439 st->print("%s", tname ? tname : "type?");
2440 }
2441 } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2442 st->print(" = ");
2443 java_dyn_MethodType::print_signature(obj, st);
2444 } else if (java_lang_boxing_object::is_instance(obj)) {
2445 st->print(" = ");
2446 java_lang_boxing_object::print(obj, st);
2447 }
2448 }
2449
2450 const char* instanceKlass::internal_name() const {
2451 return external_name();
2452 }
2453
2454 // Verification
2455
2456 class VerifyFieldClosure: public OopClosure {
2457 protected:
2458 template <class T> void do_oop_work(T* p) {
2459 guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
2460 oop obj = oopDesc::load_decode_heap_oop(p);
2461 if (!obj->is_oop_or_null()) {
2462 tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
2463 Universe::print();
2464 guarantee(false, "boom");
2465 }
2466 }
2467 public:
2468 virtual void do_oop(oop* p) { VerifyFieldClosure::do_oop_work(p); }
2469 virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
2470 };
2471
2472 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
2473 Klass::oop_verify_on(obj, st);
2474 VerifyFieldClosure blk;
2475 oop_oop_iterate(obj, &blk);
2476 }
2477
2478 #ifndef PRODUCT
2479
2480 void instanceKlass::verify_class_klass_nonstatic_oop_maps(klassOop k) {
2481 // This verification code is disabled. JDK_Version::is_gte_jdk14x_version()
2482 // cannot be called since this function is called before the VM is
2483 // able to determine what JDK version is running with.
2484 // The check below always is false since 1.4.
2485 return;
2486
2487 // This verification code temporarily disabled for the 1.4
2488 // reflection implementation since java.lang.Class now has
2489 // Java-level instance fields. Should rewrite this to handle this
2490 // case.
2491 if (!(JDK_Version::is_gte_jdk14x_version() && UseNewReflection)) {
2492 // Verify that java.lang.Class instances have a fake oop field added.
2493 instanceKlass* ik = instanceKlass::cast(k);
2494
2495 // Check that we have the right class
2496 static bool first_time = true;
2497 guarantee(k == SystemDictionary::Class_klass() && first_time, "Invalid verify of maps");
2498 first_time = false;
2499 const int extra = java_lang_Class::number_of_fake_oop_fields;
2500 guarantee(ik->nonstatic_field_size() == extra, "just checking");
2501 guarantee(ik->nonstatic_oop_map_count() == 1, "just checking");
2502 guarantee(ik->size_helper() == align_object_size(instanceOopDesc::header_size() + extra), "just checking");
2503
2504 // Check that the map is (2,extra)
2505 int offset = java_lang_Class::klass_offset;
2506
2507 OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
2508 guarantee(map->offset() == offset && map->count() == (unsigned int) extra,
2509 "sanity");
2510 }
2511 }
2512
2513 #endif // ndef PRODUCT
2514
2515 // JNIid class for jfieldIDs only
2516 // Note to reviewers:
2517 // These JNI functions are just moved over to column 1 and not changed
2518 // in the compressed oops workspace.
2519 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
2520 _holder = holder;
2521 _offset = offset;
2522 _next = next;
2523 debug_only(_is_static_field_id = false;)
2524 }
2525
2526
2527 JNIid* JNIid::find(int offset) {
2528 JNIid* current = this;
2529 while (current != NULL) {
2530 if (current->offset() == offset) return current;
2531 current = current->next();
2532 }
2533 return NULL;
2534 }
2535
2536 void JNIid::oops_do(OopClosure* f) {
2537 for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
2538 f->do_oop(cur->holder_addr());
2539 }
2540 }
2541
2542 void JNIid::deallocate(JNIid* current) {
2543 while (current != NULL) {
2544 JNIid* next = current->next();
2545 delete current;
2546 current = next;
2547 }
2548 }
2549
2550
2551 void JNIid::verify(klassOop holder) {
2552 int first_field_offset = instanceKlass::cast(holder)->offset_of_static_fields();
2553 int end_field_offset;
2554 end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
2555
2556 JNIid* current = this;
2557 while (current != NULL) {
2558 guarantee(current->holder() == holder, "Invalid klass in JNIid");
2559 #ifdef ASSERT
2560 int o = current->offset();
2561 if (current->is_static_field_id()) {
2562 guarantee(o >= first_field_offset && o < end_field_offset, "Invalid static field offset in JNIid");
2563 }
2564 #endif
2565 current = current->next();
2566 }
2567 }
2568
2569
2570 #ifdef ASSERT
2571 void instanceKlass::set_init_state(ClassState state) {
2572 bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
2573 : (_init_state < state);
2574 assert(good_state || state == allocated, "illegal state transition");
2575 _init_state = state;
2576 }
2577 #endif
2578
2579
2580 // RedefineClasses() support for previous versions:
2581
2582 // Add an information node that contains weak references to the
2583 // interesting parts of the previous version of the_class.
2584 // This is also where we clean out any unused weak references.
2585 // Note that while we delete nodes from the _previous_versions
2586 // array, we never delete the array itself until the klass is
2587 // unloaded. The has_been_redefined() query depends on that fact.
2588 //
2589 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
2590 BitMap* emcp_methods, int emcp_method_count) {
2591 assert(Thread::current()->is_VM_thread(),
2592 "only VMThread can add previous versions");
2593
2594 if (_previous_versions == NULL) {
2595 // This is the first previous version so make some space.
2596 // Start with 2 elements under the assumption that the class
2597 // won't be redefined much.
2598 _previous_versions = new (ResourceObj::C_HEAP)
2599 GrowableArray<PreviousVersionNode *>(2, true);
2600 }
2601
2602 // RC_TRACE macro has an embedded ResourceMark
2603 RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
2604 ikh->external_name(), _previous_versions->length(), emcp_method_count));
2605 constantPoolHandle cp_h(ikh->constants());
2606 jobject cp_ref;
2607 if (cp_h->is_shared()) {
2608 // a shared ConstantPool requires a regular reference; a weak
2609 // reference would be collectible
2610 cp_ref = JNIHandles::make_global(cp_h);
2611 } else {
2612 cp_ref = JNIHandles::make_weak_global(cp_h);
2613 }
2614 PreviousVersionNode * pv_node = NULL;
2615 objArrayOop old_methods = ikh->methods();
2616
2617 if (emcp_method_count == 0) {
2618 // non-shared ConstantPool gets a weak reference
2619 pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
2620 RC_TRACE(0x00000400,
2621 ("add: all methods are obsolete; flushing any EMCP weak refs"));
2622 } else {
2623 int local_count = 0;
2624 GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)
2625 GrowableArray<jweak>(emcp_method_count, true);
2626 for (int i = 0; i < old_methods->length(); i++) {
2627 if (emcp_methods->at(i)) {
2628 // this old method is EMCP so save a weak ref
2629 methodOop old_method = (methodOop) old_methods->obj_at(i);
2630 methodHandle old_method_h(old_method);
2631 jweak method_ref = JNIHandles::make_weak_global(old_method_h);
2632 method_refs->append(method_ref);
2633 if (++local_count >= emcp_method_count) {
2634 // no more EMCP methods so bail out now
2635 break;
2636 }
2637 }
2638 }
2639 // non-shared ConstantPool gets a weak reference
2640 pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
2641 }
2642
2643 _previous_versions->append(pv_node);
2644
2645 // Using weak references allows the interesting parts of previous
2646 // classes to be GC'ed when they are no longer needed. Since the
2647 // caller is the VMThread and we are at a safepoint, this is a good
2648 // time to clear out unused weak references.
2649
2650 RC_TRACE(0x00000400, ("add: previous version length=%d",
2651 _previous_versions->length()));
2652
2653 // skip the last entry since we just added it
2654 for (int i = _previous_versions->length() - 2; i >= 0; i--) {
2655 // check the previous versions array for a GC'ed weak refs
2656 pv_node = _previous_versions->at(i);
2657 cp_ref = pv_node->prev_constant_pool();
2658 assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2659 if (cp_ref == NULL) {
2660 delete pv_node;
2661 _previous_versions->remove_at(i);
2662 // Since we are traversing the array backwards, we don't have to
2663 // do anything special with the index.
2664 continue; // robustness
2665 }
2666
2667 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2668 if (cp == NULL) {
2669 // this entry has been GC'ed so remove it
2670 delete pv_node;
2671 _previous_versions->remove_at(i);
2672 // Since we are traversing the array backwards, we don't have to
2673 // do anything special with the index.
2674 continue;
2675 } else {
2676 RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
2677 }
2678
2679 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2680 if (method_refs != NULL) {
2681 RC_TRACE(0x00000400, ("add: previous methods length=%d",
2682 method_refs->length()));
2683 for (int j = method_refs->length() - 1; j >= 0; j--) {
2684 jweak method_ref = method_refs->at(j);
2685 assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2686 if (method_ref == NULL) {
2687 method_refs->remove_at(j);
2688 // Since we are traversing the array backwards, we don't have to
2689 // do anything special with the index.
2690 continue; // robustness
2691 }
2692
2693 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2694 if (method == NULL || emcp_method_count == 0) {
2695 // This method entry has been GC'ed or the current
2696 // RedefineClasses() call has made all methods obsolete
2697 // so remove it.
2698 JNIHandles::destroy_weak_global(method_ref);
2699 method_refs->remove_at(j);
2700 } else {
2701 // RC_TRACE macro has an embedded ResourceMark
2702 RC_TRACE(0x00000400,
2703 ("add: %s(%s): previous method @%d in version @%d is alive",
2704 method->name()->as_C_string(), method->signature()->as_C_string(),
2705 j, i));
2706 }
2707 }
2708 }
2709 }
2710
2711 int obsolete_method_count = old_methods->length() - emcp_method_count;
2712
2713 if (emcp_method_count != 0 && obsolete_method_count != 0 &&
2714 _previous_versions->length() > 1) {
2715 // We have a mix of obsolete and EMCP methods. If there is more
2716 // than the previous version that we just added, then we have to
2717 // clear out any matching EMCP method entries the hard way.
2718 int local_count = 0;
2719 for (int i = 0; i < old_methods->length(); i++) {
2720 if (!emcp_methods->at(i)) {
2721 // only obsolete methods are interesting
2722 methodOop old_method = (methodOop) old_methods->obj_at(i);
2723 symbolOop m_name = old_method->name();
2724 symbolOop m_signature = old_method->signature();
2725
2726 // skip the last entry since we just added it
2727 for (int j = _previous_versions->length() - 2; j >= 0; j--) {
2728 // check the previous versions array for a GC'ed weak refs
2729 pv_node = _previous_versions->at(j);
2730 cp_ref = pv_node->prev_constant_pool();
2731 assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2732 if (cp_ref == NULL) {
2733 delete pv_node;
2734 _previous_versions->remove_at(j);
2735 // Since we are traversing the array backwards, we don't have to
2736 // do anything special with the index.
2737 continue; // robustness
2738 }
2739
2740 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2741 if (cp == NULL) {
2742 // this entry has been GC'ed so remove it
2743 delete pv_node;
2744 _previous_versions->remove_at(j);
2745 // Since we are traversing the array backwards, we don't have to
2746 // do anything special with the index.
2747 continue;
2748 }
2749
2750 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2751 if (method_refs == NULL) {
2752 // We have run into a PreviousVersion generation where
2753 // all methods were made obsolete during that generation's
2754 // RedefineClasses() operation. At the time of that
2755 // operation, all EMCP methods were flushed so we don't
2756 // have to go back any further.
2757 //
2758 // A NULL method_refs is different than an empty method_refs.
2759 // We cannot infer any optimizations about older generations
2760 // from an empty method_refs for the current generation.
2761 break;
2762 }
2763
2764 for (int k = method_refs->length() - 1; k >= 0; k--) {
2765 jweak method_ref = method_refs->at(k);
2766 assert(method_ref != NULL,
2767 "weak method ref was unexpectedly cleared");
2768 if (method_ref == NULL) {
2769 method_refs->remove_at(k);
2770 // Since we are traversing the array backwards, we don't
2771 // have to do anything special with the index.
2772 continue; // robustness
2773 }
2774
2775 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2776 if (method == NULL) {
2777 // this method entry has been GC'ed so skip it
2778 JNIHandles::destroy_weak_global(method_ref);
2779 method_refs->remove_at(k);
2780 continue;
2781 }
2782
2783 if (method->name() == m_name &&
2784 method->signature() == m_signature) {
2785 // The current RedefineClasses() call has made all EMCP
2786 // versions of this method obsolete so mark it as obsolete
2787 // and remove the weak ref.
2788 RC_TRACE(0x00000400,
2789 ("add: %s(%s): flush obsolete method @%d in version @%d",
2790 m_name->as_C_string(), m_signature->as_C_string(), k, j));
2791
2792 method->set_is_obsolete();
2793 JNIHandles::destroy_weak_global(method_ref);
2794 method_refs->remove_at(k);
2795 break;
2796 }
2797 }
2798
2799 // The previous loop may not find a matching EMCP method, but
2800 // that doesn't mean that we can optimize and not go any
2801 // further back in the PreviousVersion generations. The EMCP
2802 // method for this generation could have already been GC'ed,
2803 // but there still may be an older EMCP method that has not
2804 // been GC'ed.
2805 }
2806
2807 if (++local_count >= obsolete_method_count) {
2808 // no more obsolete methods so bail out now
2809 break;
2810 }
2811 }
2812 }
2813 }
2814 } // end add_previous_version()
2815
2816
2817 // Determine if instanceKlass has a previous version.
2818 bool instanceKlass::has_previous_version() const {
2819 if (_previous_versions == NULL) {
2820 // no previous versions array so answer is easy
2821 return false;
2822 }
2823
2824 for (int i = _previous_versions->length() - 1; i >= 0; i--) {
2825 // Check the previous versions array for an info node that hasn't
2826 // been GC'ed
2827 PreviousVersionNode * pv_node = _previous_versions->at(i);
2828
2829 jobject cp_ref = pv_node->prev_constant_pool();
2830 assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
2831 if (cp_ref == NULL) {
2832 continue; // robustness
2833 }
2834
2835 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2836 if (cp != NULL) {
2837 // we have at least one previous version
2838 return true;
2839 }
2840
2841 // We don't have to check the method refs. If the constant pool has
2842 // been GC'ed then so have the methods.
2843 }
2844
2845 // all of the underlying nodes' info has been GC'ed
2846 return false;
2847 } // end has_previous_version()
2848
2849 methodOop instanceKlass::method_with_idnum(int idnum) {
2850 methodOop m = NULL;
2851 if (idnum < methods()->length()) {
2852 m = (methodOop) methods()->obj_at(idnum);
2853 }
2854 if (m == NULL || m->method_idnum() != idnum) {
2855 for (int index = 0; index < methods()->length(); ++index) {
2856 m = (methodOop) methods()->obj_at(index);
2857 if (m->method_idnum() == idnum) {
2858 return m;
2859 }
2860 }
2861 }
2862 return m;
2863 }
2864
2865
2866 // Set the annotation at 'idnum' to 'anno'.
2867 // We don't want to create or extend the array if 'anno' is NULL, since that is the
2868 // default value. However, if the array exists and is long enough, we must set NULL values.
2869 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
2870 objArrayOop md = *md_p;
2871 if (md != NULL && md->length() > idnum) {
2872 md->obj_at_put(idnum, anno);
2873 } else if (anno != NULL) {
2874 // create the array
2875 int length = MAX2(idnum+1, (int)_idnum_allocated_count);
2876 md = oopFactory::new_system_objArray(length, Thread::current());
2877 if (*md_p != NULL) {
2878 // copy the existing entries
2879 for (int index = 0; index < (*md_p)->length(); index++) {
2880 md->obj_at_put(index, (*md_p)->obj_at(index));
2881 }
2882 }
2883 set_annotations(md, md_p);
2884 md->obj_at_put(idnum, anno);
2885 } // if no array and idnum isn't included there is nothing to do
2886 }
2887
2888 // Construct a PreviousVersionNode entry for the array hung off
2889 // the instanceKlass.
2890 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
2891 bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
2892
2893 _prev_constant_pool = prev_constant_pool;
2894 _prev_cp_is_weak = prev_cp_is_weak;
2895 _prev_EMCP_methods = prev_EMCP_methods;
2896 }
2897
2898
2899 // Destroy a PreviousVersionNode
2900 PreviousVersionNode::~PreviousVersionNode() {
2901 if (_prev_constant_pool != NULL) {
2902 if (_prev_cp_is_weak) {
2903 JNIHandles::destroy_weak_global(_prev_constant_pool);
2904 } else {
2905 JNIHandles::destroy_global(_prev_constant_pool);
2906 }
2907 }
2908
2909 if (_prev_EMCP_methods != NULL) {
2910 for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
2911 jweak method_ref = _prev_EMCP_methods->at(i);
2912 if (method_ref != NULL) {
2913 JNIHandles::destroy_weak_global(method_ref);
2914 }
2915 }
2916 delete _prev_EMCP_methods;
2917 }
2918 }
2919
2920
2921 // Construct a PreviousVersionInfo entry
2922 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
2923 _prev_constant_pool_handle = constantPoolHandle(); // NULL handle
2924 _prev_EMCP_method_handles = NULL;
2925
2926 jobject cp_ref = pv_node->prev_constant_pool();
2927 assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
2928 if (cp_ref == NULL) {
2929 return; // robustness
2930 }
2931
2932 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2933 if (cp == NULL) {
2934 // Weak reference has been GC'ed. Since the constant pool has been
2935 // GC'ed, the methods have also been GC'ed.
2936 return;
2937 }
2938
2939 // make the constantPoolOop safe to return
2940 _prev_constant_pool_handle = constantPoolHandle(cp);
2941
2942 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2943 if (method_refs == NULL) {
2944 // the instanceKlass did not have any EMCP methods
2945 return;
2946 }
2947
2948 _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
2949
2950 int n_methods = method_refs->length();
2951 for (int i = 0; i < n_methods; i++) {
2952 jweak method_ref = method_refs->at(i);
2953 assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2954 if (method_ref == NULL) {
2955 continue; // robustness
2956 }
2957
2958 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2959 if (method == NULL) {
2960 // this entry has been GC'ed so skip it
2961 continue;
2962 }
2963
2964 // make the methodOop safe to return
2965 _prev_EMCP_method_handles->append(methodHandle(method));
2966 }
2967 }
2968
2969
2970 // Destroy a PreviousVersionInfo
2971 PreviousVersionInfo::~PreviousVersionInfo() {
2972 // Since _prev_EMCP_method_handles is not C-heap allocated, we
2973 // don't have to delete it.
2974 }
2975
2976
2977 // Construct a helper for walking the previous versions array
2978 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
2979 _previous_versions = ik->previous_versions();
2980 _current_index = 0;
2981 // _hm needs no initialization
2982 _current_p = NULL;
2983 }
2984
2985
2986 // Destroy a PreviousVersionWalker
2987 PreviousVersionWalker::~PreviousVersionWalker() {
2988 // Delete the current info just in case the caller didn't walk to
2989 // the end of the previous versions list. No harm if _current_p is
2990 // already NULL.
2991 delete _current_p;
2992
2993 // When _hm is destroyed, all the Handles returned in
2994 // PreviousVersionInfo objects will be destroyed.
2995 // Also, after this destructor is finished it will be
2996 // safe to delete the GrowableArray allocated in the
2997 // PreviousVersionInfo objects.
2998 }
2999
3000
3001 // Return the interesting information for the next previous version
3002 // of the klass. Returns NULL if there are no more previous versions.
3003 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
3004 if (_previous_versions == NULL) {
3005 // no previous versions so nothing to return
3006 return NULL;
3007 }
3008
3009 delete _current_p; // cleanup the previous info for the caller
3010 _current_p = NULL; // reset to NULL so we don't delete same object twice
3011
3012 int length = _previous_versions->length();
3013
3014 while (_current_index < length) {
3015 PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
3016 PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP)
3017 PreviousVersionInfo(pv_node);
3018
3019 constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
3020 if (cp_h.is_null()) {
3021 delete pv_info;
3022
3023 // The underlying node's info has been GC'ed so try the next one.
3024 // We don't have to check the methods. If the constant pool has
3025 // GC'ed then so have the methods.
3026 continue;
3027 }
3028
3029 // Found a node with non GC'ed info so return it. The caller will
3030 // need to delete pv_info when they are done with it.
3031 _current_p = pv_info;
3032 return pv_info;
3033 }
3034
3035 // all of the underlying nodes' info has been GC'ed
3036 return NULL;
3037 } // end next_previous_version()