1 /*
2 * Copyright (c) 1997, 2011, 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/symbol.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/g1RemSet.inline.hpp"
66 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
67 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
68 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
69 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
70 #include "oops/oop.pcgc.inline.hpp"
71 #endif
72 #ifdef COMPILER1
73 #include "c1/c1_Compiler.hpp"
74 #endif
75
76 #ifdef DTRACE_ENABLED
77
78 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
79 char*, intptr_t, oop, intptr_t);
80 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
81 char*, intptr_t, oop, intptr_t, int);
82 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
83 char*, intptr_t, oop, intptr_t, int);
84 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
85 char*, intptr_t, oop, intptr_t, int);
86 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
87 char*, intptr_t, oop, intptr_t, int);
88 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
89 char*, intptr_t, oop, intptr_t, int);
90 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
91 char*, intptr_t, oop, intptr_t, int);
92 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
93 char*, intptr_t, oop, intptr_t, int);
94
95 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) \
96 { \
97 char* data = NULL; \
98 int len = 0; \
99 Symbol* name = (clss)->name(); \
100 if (name != NULL) { \
101 data = (char*)name->bytes(); \
102 len = name->utf8_length(); \
103 } \
104 HS_DTRACE_PROBE4(hotspot, class__initialization__##type, \
105 data, len, (clss)->class_loader(), thread_type); \
106 }
107
108 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
109 { \
110 char* data = NULL; \
111 int len = 0; \
112 Symbol* name = (clss)->name(); \
113 if (name != NULL) { \
114 data = (char*)name->bytes(); \
115 len = name->utf8_length(); \
116 } \
117 HS_DTRACE_PROBE5(hotspot, class__initialization__##type, \
118 data, len, (clss)->class_loader(), thread_type, wait); \
119 }
120
121 #else // ndef DTRACE_ENABLED
122
123 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
124 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
125
126 #endif // ndef DTRACE_ENABLED
127
128 bool instanceKlass::should_be_initialized() const {
129 return !is_initialized();
130 }
131
132 klassVtable* instanceKlass::vtable() const {
133 return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());
134 }
135
136 klassItable* instanceKlass::itable() const {
137 return new klassItable(as_klassOop());
138 }
139
140 void instanceKlass::eager_initialize(Thread *thread) {
141 if (!EagerInitialization) return;
142
143 if (this->is_not_initialized()) {
144 // abort if the the class has a class initializer
145 if (this->class_initializer() != NULL) return;
146
147 // abort if it is java.lang.Object (initialization is handled in genesis)
148 klassOop super = this->super();
149 if (super == NULL) return;
150
151 // abort if the super class should be initialized
152 if (!instanceKlass::cast(super)->is_initialized()) return;
153
154 // call body to expose the this pointer
155 instanceKlassHandle this_oop(thread, this->as_klassOop());
156 eager_initialize_impl(this_oop);
157 }
158 }
159
160
161 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
162 EXCEPTION_MARK;
163 ObjectLocker ol(this_oop, THREAD);
164
165 // abort if someone beat us to the initialization
166 if (!this_oop->is_not_initialized()) return; // note: not equivalent to is_initialized()
167
168 ClassState old_state = this_oop->_init_state;
169 link_class_impl(this_oop, true, THREAD);
170 if (HAS_PENDING_EXCEPTION) {
171 CLEAR_PENDING_EXCEPTION;
172 // Abort if linking the class throws an exception.
173
174 // Use a test to avoid redundantly resetting the state if there's
175 // no change. Set_init_state() asserts that state changes make
176 // progress, whereas here we might just be spinning in place.
177 if( old_state != this_oop->_init_state )
178 this_oop->set_init_state (old_state);
179 } else {
180 // linking successfull, mark class as initialized
181 this_oop->set_init_state (fully_initialized);
182 // trace
183 if (TraceClassInitialization) {
184 ResourceMark rm(THREAD);
185 tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
186 }
187 }
188 }
189
190
191 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
192 // process. The step comments refers to the procedure described in that section.
193 // Note: implementation moved to static method to expose the this pointer.
194 void instanceKlass::initialize(TRAPS) {
195 if (this->should_be_initialized()) {
196 HandleMark hm(THREAD);
197 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
198 initialize_impl(this_oop, CHECK);
199 // Note: at this point the class may be initialized
200 // OR it may be in the state of being initialized
201 // in case of recursive initialization!
202 } else {
203 assert(is_initialized(), "sanity check");
204 }
205 }
206
207
208 bool instanceKlass::verify_code(
209 instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
210 // 1) Verify the bytecodes
211 Verifier::Mode mode =
212 throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
213 return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
214 }
215
216
217 // Used exclusively by the shared spaces dump mechanism to prevent
218 // classes mapped into the shared regions in new VMs from appearing linked.
219
220 void instanceKlass::unlink_class() {
221 assert(is_linked(), "must be linked");
222 _init_state = loaded;
223 }
224
225 void instanceKlass::link_class(TRAPS) {
226 assert(is_loaded(), "must be loaded");
227 if (!is_linked()) {
228 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
229 link_class_impl(this_oop, true, CHECK);
230 }
231 }
232
233 // Called to verify that a class can link during initialization, without
234 // throwing a VerifyError.
235 bool instanceKlass::link_class_or_fail(TRAPS) {
236 assert(is_loaded(), "must be loaded");
237 if (!is_linked()) {
238 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
239 link_class_impl(this_oop, false, CHECK_false);
240 }
241 return is_linked();
242 }
243
244 bool instanceKlass::link_class_impl(
245 instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
246 // check for error state
247 if (this_oop->is_in_error_state()) {
248 ResourceMark rm(THREAD);
249 THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
250 this_oop->external_name(), false);
251 }
252 // return if already verified
253 if (this_oop->is_linked()) {
254 return true;
255 }
256
257 // Timing
258 // timer handles recursion
259 assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
260 JavaThread* jt = (JavaThread*)THREAD;
261
262 // link super class before linking this class
263 instanceKlassHandle super(THREAD, this_oop->super());
264 if (super.not_null()) {
265 if (super->is_interface()) { // check if super class is an interface
266 ResourceMark rm(THREAD);
267 Exceptions::fthrow(
268 THREAD_AND_LOCATION,
269 vmSymbols::java_lang_IncompatibleClassChangeError(),
270 "class %s has interface %s as super class",
271 this_oop->external_name(),
272 super->external_name()
273 );
274 return false;
275 }
276
277 link_class_impl(super, throw_verifyerror, CHECK_false);
278 }
279
280 // link all interfaces implemented by this class before linking this class
281 objArrayHandle interfaces (THREAD, this_oop->local_interfaces());
282 int num_interfaces = interfaces->length();
283 for (int index = 0; index < num_interfaces; index++) {
284 HandleMark hm(THREAD);
285 instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));
286 link_class_impl(ih, throw_verifyerror, CHECK_false);
287 }
288
289 // in case the class is linked in the process of linking its superclasses
290 if (this_oop->is_linked()) {
291 return true;
292 }
293
294 // trace only the link time for this klass that includes
295 // the verification time
296 PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
297 ClassLoader::perf_class_link_selftime(),
298 ClassLoader::perf_classes_linked(),
299 jt->get_thread_stat()->perf_recursion_counts_addr(),
300 jt->get_thread_stat()->perf_timers_addr(),
301 PerfClassTraceTime::CLASS_LINK);
302
303 // verification & rewriting
304 {
305 ObjectLocker ol(this_oop, THREAD);
306 // rewritten will have been set if loader constraint error found
307 // on an earlier link attempt
308 // don't verify or rewrite if already rewritten
309 if (!this_oop->is_linked()) {
310 if (!this_oop->is_rewritten()) {
311 {
312 // Timer includes any side effects of class verification (resolution,
313 // etc), but not recursive entry into verify_code().
314 PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
315 ClassLoader::perf_class_verify_selftime(),
316 ClassLoader::perf_classes_verified(),
317 jt->get_thread_stat()->perf_recursion_counts_addr(),
318 jt->get_thread_stat()->perf_timers_addr(),
319 PerfClassTraceTime::CLASS_VERIFY);
320 bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
321 if (!verify_ok) {
322 return false;
323 }
324 }
325
326 // Just in case a side-effect of verify linked this class already
327 // (which can sometimes happen since the verifier loads classes
328 // using custom class loaders, which are free to initialize things)
329 if (this_oop->is_linked()) {
330 return true;
331 }
332
333 // also sets rewritten
334 this_oop->rewrite_class(CHECK_false);
335 }
336
337 // Initialize the vtable and interface table after
338 // methods have been rewritten since rewrite may
339 // fabricate new methodOops.
340 // also does loader constraint checking
341 if (!this_oop()->is_shared()) {
342 ResourceMark rm(THREAD);
343 this_oop->vtable()->initialize_vtable(true, CHECK_false);
344 this_oop->itable()->initialize_itable(true, CHECK_false);
345 }
346 #ifdef ASSERT
347 else {
348 ResourceMark rm(THREAD);
349 this_oop->vtable()->verify(tty, true);
350 // In case itable verification is ever added.
351 // this_oop->itable()->verify(tty, true);
352 }
353 #endif
354 this_oop->set_init_state(linked);
355 if (JvmtiExport::should_post_class_prepare()) {
356 Thread *thread = THREAD;
357 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
358 JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
359 }
360 }
361 }
362 return true;
363 }
364
365
366 // Rewrite the byte codes of all of the methods of a class.
367 // Three cases:
368 // During the link of a newly loaded class.
369 // During the preloading of classes to be written to the shared spaces.
370 // - Rewrite the methods and update the method entry points.
371 //
372 // During the link of a class in the shared spaces.
373 // - The methods were already rewritten, update the metho entry points.
374 //
375 // The rewriter must be called exactly once. Rewriting must happen after
376 // verification but before the first method of the class is executed.
377
378 void instanceKlass::rewrite_class(TRAPS) {
379 assert(is_loaded(), "must be loaded");
380 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
381 if (this_oop->is_rewritten()) {
382 assert(this_oop()->is_shared(), "rewriting an unshared class?");
383 return;
384 }
385 Rewriter::rewrite(this_oop, CHECK); // No exception can happen here
386 this_oop->set_rewritten();
387 }
388
389
390 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
391 // Make sure klass is linked (verified) before initialization
392 // A class could already be verified, since it has been reflected upon.
393 this_oop->link_class(CHECK);
394
395 DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);
396
397 bool wait = false;
398
399 // refer to the JVM book page 47 for description of steps
400 // Step 1
401 { ObjectLocker ol(this_oop, THREAD);
402
403 Thread *self = THREAD; // it's passed the current thread
404
405 // Step 2
406 // If we were to use wait() instead of waitInterruptibly() then
407 // we might end up throwing IE from link/symbol resolution sites
408 // that aren't expected to throw. This would wreak havoc. See 6320309.
409 while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
410 wait = true;
411 ol.waitUninterruptibly(CHECK);
412 }
413
414 // Step 3
415 if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
416 DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);
417 return;
418 }
419
420 // Step 4
421 if (this_oop->is_initialized()) {
422 DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);
423 return;
424 }
425
426 // Step 5
427 if (this_oop->is_in_error_state()) {
428 DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);
429 ResourceMark rm(THREAD);
430 const char* desc = "Could not initialize class ";
431 const char* className = this_oop->external_name();
432 size_t msglen = strlen(desc) + strlen(className) + 1;
433 char* message = NEW_RESOURCE_ARRAY(char, msglen);
434 if (NULL == message) {
435 // Out of memory: can't create detailed error message
436 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
437 } else {
438 jio_snprintf(message, msglen, "%s%s", desc, className);
439 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
440 }
441 }
442
443 // Step 6
444 this_oop->set_init_state(being_initialized);
445 this_oop->set_init_thread(self);
446 }
447
448 // Step 7
449 klassOop super_klass = this_oop->super();
450 if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {
451 Klass::cast(super_klass)->initialize(THREAD);
452
453 if (HAS_PENDING_EXCEPTION) {
454 Handle e(THREAD, PENDING_EXCEPTION);
455 CLEAR_PENDING_EXCEPTION;
456 {
457 EXCEPTION_MARK;
458 this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
459 CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, superclass initialization error is thrown below
460 }
461 DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);
462 THROW_OOP(e());
463 }
464 }
465
466 // Step 8
467 {
468 assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
469 JavaThread* jt = (JavaThread*)THREAD;
470 DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);
471 // Timer includes any side effects of class initialization (resolution,
472 // etc), but not recursive entry into call_class_initializer().
473 PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
474 ClassLoader::perf_class_init_selftime(),
475 ClassLoader::perf_classes_inited(),
476 jt->get_thread_stat()->perf_recursion_counts_addr(),
477 jt->get_thread_stat()->perf_timers_addr(),
478 PerfClassTraceTime::CLASS_CLINIT);
479 this_oop->call_class_initializer(THREAD);
480 }
481
482 // Step 9
483 if (!HAS_PENDING_EXCEPTION) {
484 this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
485 { ResourceMark rm(THREAD);
486 debug_only(this_oop->vtable()->verify(tty, true);)
487 }
488 }
489 else {
490 // Step 10 and 11
491 Handle e(THREAD, PENDING_EXCEPTION);
492 CLEAR_PENDING_EXCEPTION;
493 {
494 EXCEPTION_MARK;
495 this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
496 CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, class initialization error is thrown below
497 }
498 DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);
499 if (e->is_a(SystemDictionary::Error_klass())) {
500 THROW_OOP(e());
501 } else {
502 JavaCallArguments args(e);
503 THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
504 vmSymbols::throwable_void_signature(),
505 &args);
506 }
507 }
508 DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);
509 }
510
511
512 // Note: implementation moved to static method to expose the this pointer.
513 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
514 instanceKlassHandle kh(THREAD, this->as_klassOop());
515 set_initialization_state_and_notify_impl(kh, state, CHECK);
516 }
517
518 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
519 ObjectLocker ol(this_oop, THREAD);
520 this_oop->set_init_state(state);
521 ol.notify_all(CHECK);
522 }
523
524 void instanceKlass::add_implementor(klassOop k) {
525 assert(Compile_lock->owned_by_self(), "");
526 // Filter out my subinterfaces.
527 // (Note: Interfaces are never on the subklass list.)
528 if (instanceKlass::cast(k)->is_interface()) return;
529
530 // Filter out subclasses whose supers already implement me.
531 // (Note: CHA must walk subclasses of direct implementors
532 // in order to locate indirect implementors.)
533 klassOop sk = instanceKlass::cast(k)->super();
534 if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))
535 // We only need to check one immediate superclass, since the
536 // implements_interface query looks at transitive_interfaces.
537 // Any supers of the super have the same (or fewer) transitive_interfaces.
538 return;
539
540 // Update number of implementors
541 int i = _nof_implementors++;
542
543 // Record this implementor, if there are not too many already
544 if (i < implementors_limit) {
545 assert(_implementors[i] == NULL, "should be exactly one implementor");
546 oop_store_without_check((oop*)&_implementors[i], k);
547 } else if (i == implementors_limit) {
548 // clear out the list on first overflow
549 for (int i2 = 0; i2 < implementors_limit; i2++)
550 oop_store_without_check((oop*)&_implementors[i2], NULL);
551 }
552
553 // The implementor also implements the transitive_interfaces
554 for (int index = 0; index < local_interfaces()->length(); index++) {
555 instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);
556 }
557 }
558
559 void instanceKlass::init_implementor() {
560 for (int i = 0; i < implementors_limit; i++)
561 oop_store_without_check((oop*)&_implementors[i], NULL);
562 _nof_implementors = 0;
563 }
564
565
566 void instanceKlass::process_interfaces(Thread *thread) {
567 // link this class into the implementors list of every interface it implements
568 KlassHandle this_as_oop (thread, this->as_klassOop());
569 for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
570 assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");
571 instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));
572 assert(interf->is_interface(), "expected interface");
573 interf->add_implementor(this_as_oop());
574 }
575 }
576
577 bool instanceKlass::can_be_primary_super_slow() const {
578 if (is_interface())
579 return false;
580 else
581 return Klass::can_be_primary_super_slow();
582 }
583
584 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
585 // The secondaries are the implemented interfaces.
586 instanceKlass* ik = instanceKlass::cast(as_klassOop());
587 objArrayHandle interfaces (THREAD, ik->transitive_interfaces());
588 int num_secondaries = num_extra_slots + interfaces->length();
589 if (num_secondaries == 0) {
590 return Universe::the_empty_system_obj_array();
591 } else if (num_extra_slots == 0) {
592 return interfaces();
593 } else {
594 // a mix of both
595 objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);
596 for (int i = 0; i < interfaces->length(); i++) {
597 secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));
598 }
599 return secondaries;
600 }
601 }
602
603 bool instanceKlass::compute_is_subtype_of(klassOop k) {
604 if (Klass::cast(k)->is_interface()) {
605 return implements_interface(k);
606 } else {
607 return Klass::compute_is_subtype_of(k);
608 }
609 }
610
611 bool instanceKlass::implements_interface(klassOop k) const {
612 if (as_klassOop() == k) return true;
613 assert(Klass::cast(k)->is_interface(), "should be an interface class");
614 for (int i = 0; i < transitive_interfaces()->length(); i++) {
615 if (transitive_interfaces()->obj_at(i) == k) {
616 return true;
617 }
618 }
619 return false;
620 }
621
622 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {
623 if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
624 if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
625 report_java_out_of_memory("Requested array size exceeds VM limit");
626 THROW_OOP_0(Universe::out_of_memory_error_array_size());
627 }
628 int size = objArrayOopDesc::object_size(length);
629 klassOop ak = array_klass(n, CHECK_NULL);
630 KlassHandle h_ak (THREAD, ak);
631 objArrayOop o =
632 (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
633 return o;
634 }
635
636 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {
637 if (TraceFinalizerRegistration) {
638 tty->print("Registered ");
639 i->print_value_on(tty);
640 tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
641 }
642 instanceHandle h_i(THREAD, i);
643 // Pass the handle as argument, JavaCalls::call expects oop as jobjects
644 JavaValue result(T_VOID);
645 JavaCallArguments args(h_i);
646 methodHandle mh (THREAD, Universe::finalizer_register_method());
647 JavaCalls::call(&result, mh, &args, CHECK_NULL);
648 return h_i();
649 }
650
651 instanceOop instanceKlass::allocate_instance(TRAPS) {
652 bool has_finalizer_flag = has_finalizer(); // Query before possible GC
653 int size = size_helper(); // Query before forming handle.
654
655 KlassHandle h_k(THREAD, as_klassOop());
656
657 instanceOop i;
658
659 i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
660 if (has_finalizer_flag && !RegisterFinalizersAtInit) {
661 i = register_finalizer(i, CHECK_NULL);
662 }
663 return i;
664 }
665
666 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {
667 // Finalizer registration occurs in the Object.<init> constructor
668 // and constructors normally aren't run when allocating perm
669 // instances so simply disallow finalizable perm objects. This can
670 // be relaxed if a need for it is found.
671 assert(!has_finalizer(), "perm objects not allowed to have finalizers");
672 int size = size_helper(); // Query before forming handle.
673 KlassHandle h_k(THREAD, as_klassOop());
674 instanceOop i = (instanceOop)
675 CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
676 return i;
677 }
678
679 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
680 if (is_interface() || is_abstract()) {
681 ResourceMark rm(THREAD);
682 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
683 : vmSymbols::java_lang_InstantiationException(), external_name());
684 }
685 if (as_klassOop() == SystemDictionary::Class_klass()) {
686 ResourceMark rm(THREAD);
687 THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
688 : vmSymbols::java_lang_IllegalAccessException(), external_name());
689 }
690 }
691
692 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
693 instanceKlassHandle this_oop(THREAD, as_klassOop());
694 return array_klass_impl(this_oop, or_null, n, THREAD);
695 }
696
697 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
698 if (this_oop->array_klasses() == NULL) {
699 if (or_null) return NULL;
700
701 ResourceMark rm;
702 JavaThread *jt = (JavaThread *)THREAD;
703 {
704 // Atomic creation of array_klasses
705 MutexLocker mc(Compile_lock, THREAD); // for vtables
706 MutexLocker ma(MultiArray_lock, THREAD);
707
708 // Check if update has already taken place
709 if (this_oop->array_klasses() == NULL) {
710 objArrayKlassKlass* oakk =
711 (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();
712
713 klassOop k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);
714 this_oop->set_array_klasses(k);
715 }
716 }
717 }
718 // _this will always be set at this point
719 objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();
720 if (or_null) {
721 return oak->array_klass_or_null(n);
722 }
723 return oak->array_klass(n, CHECK_NULL);
724 }
725
726 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {
727 return array_klass_impl(or_null, 1, THREAD);
728 }
729
730 void instanceKlass::call_class_initializer(TRAPS) {
731 instanceKlassHandle ik (THREAD, as_klassOop());
732 call_class_initializer_impl(ik, THREAD);
733 }
734
735 static int call_class_initializer_impl_counter = 0; // for debugging
736
737 methodOop instanceKlass::class_initializer() {
738 methodOop clinit = find_method(
739 vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
740 if (clinit != NULL && clinit->has_valid_initializer_flags()) {
741 return clinit;
742 }
743 return NULL;
744 }
745
746 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
747 methodHandle h_method(THREAD, this_oop->class_initializer());
748 assert(!this_oop->is_initialized(), "we cannot initialize twice");
749 if (TraceClassInitialization) {
750 tty->print("%d Initializing ", call_class_initializer_impl_counter++);
751 this_oop->name()->print_value();
752 tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
753 }
754 if (h_method() != NULL) {
755 JavaCallArguments args; // No arguments
756 JavaValue result(T_VOID);
757 JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
758 }
759 }
760
761
762 void instanceKlass::mask_for(methodHandle method, int bci,
763 InterpreterOopMap* entry_for) {
764 // Dirty read, then double-check under a lock.
765 if (_oop_map_cache == NULL) {
766 // Otherwise, allocate a new one.
767 MutexLocker x(OopMapCacheAlloc_lock);
768 // First time use. Allocate a cache in C heap
769 if (_oop_map_cache == NULL) {
770 _oop_map_cache = new OopMapCache();
771 }
772 }
773 // _oop_map_cache is constant after init; lookup below does is own locking.
774 _oop_map_cache->lookup(method, bci, entry_for);
775 }
776
777
778 bool instanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
779 const int n = fields()->length();
780 for (int i = 0; i < n; i += next_offset ) {
781 int name_index = fields()->ushort_at(i + name_index_offset);
782 int sig_index = fields()->ushort_at(i + signature_index_offset);
783 Symbol* f_name = constants()->symbol_at(name_index);
784 Symbol* f_sig = constants()->symbol_at(sig_index);
785 if (f_name == name && f_sig == sig) {
786 fd->initialize(as_klassOop(), i);
787 return true;
788 }
789 }
790 return false;
791 }
792
793
794 void instanceKlass::shared_symbols_iterate(SymbolClosure* closure) {
795 Klass::shared_symbols_iterate(closure);
796 closure->do_symbol(&_generic_signature);
797 closure->do_symbol(&_source_file_name);
798 closure->do_symbol(&_source_debug_extension);
799
800 const int n = fields()->length();
801 for (int i = 0; i < n; i += next_offset ) {
802 int name_index = fields()->ushort_at(i + name_index_offset);
803 closure->do_symbol(constants()->symbol_at_addr(name_index));
804 int sig_index = fields()->ushort_at(i + signature_index_offset);
805 closure->do_symbol(constants()->symbol_at_addr(sig_index));
806 }
807 }
808
809
810 klassOop instanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
811 const int n = local_interfaces()->length();
812 for (int i = 0; i < n; i++) {
813 klassOop intf1 = klassOop(local_interfaces()->obj_at(i));
814 assert(Klass::cast(intf1)->is_interface(), "just checking type");
815 // search for field in current interface
816 if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
817 assert(fd->is_static(), "interface field must be static");
818 return intf1;
819 }
820 // search for field in direct superinterfaces
821 klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
822 if (intf2 != NULL) return intf2;
823 }
824 // otherwise field lookup fails
825 return NULL;
826 }
827
828
829 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
830 // search order according to newest JVM spec (5.4.3.2, p.167).
831 // 1) search for field in current klass
832 if (find_local_field(name, sig, fd)) {
833 return as_klassOop();
834 }
835 // 2) search for field recursively in direct superinterfaces
836 { klassOop intf = find_interface_field(name, sig, fd);
837 if (intf != NULL) return intf;
838 }
839 // 3) apply field lookup recursively if superclass exists
840 { klassOop supr = super();
841 if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);
842 }
843 // 4) otherwise field lookup fails
844 return NULL;
845 }
846
847
848 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
849 // search order according to newest JVM spec (5.4.3.2, p.167).
850 // 1) search for field in current klass
851 if (find_local_field(name, sig, fd)) {
852 if (fd->is_static() == is_static) return as_klassOop();
853 }
854 // 2) search for field recursively in direct superinterfaces
855 if (is_static) {
856 klassOop intf = find_interface_field(name, sig, fd);
857 if (intf != NULL) return intf;
858 }
859 // 3) apply field lookup recursively if superclass exists
860 { klassOop supr = super();
861 if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
862 }
863 // 4) otherwise field lookup fails
864 return NULL;
865 }
866
867
868 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
869 int length = fields()->length();
870 for (int i = 0; i < length; i += next_offset) {
871 if (offset_from_fields( i ) == offset) {
872 fd->initialize(as_klassOop(), i);
873 if (fd->is_static() == is_static) return true;
874 }
875 }
876 return false;
877 }
878
879
880 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
881 klassOop klass = as_klassOop();
882 while (klass != NULL) {
883 if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
884 return true;
885 }
886 klass = Klass::cast(klass)->super();
887 }
888 return false;
889 }
890
891
892 void instanceKlass::methods_do(void f(methodOop method)) {
893 int len = methods()->length();
894 for (int index = 0; index < len; index++) {
895 methodOop m = methodOop(methods()->obj_at(index));
896 assert(m->is_method(), "must be method");
897 f(m);
898 }
899 }
900
901 void instanceKlass::do_local_static_fields(FieldClosure* cl) {
902 fieldDescriptor fd;
903 int length = fields()->length();
904 for (int i = 0; i < length; i += next_offset) {
905 fd.initialize(as_klassOop(), i);
906 if (fd.is_static()) cl->do_field(&fd);
907 }
908 }
909
910
911 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
912 instanceKlassHandle h_this(THREAD, as_klassOop());
913 do_local_static_fields_impl(h_this, f, CHECK);
914 }
915
916
917 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
918 fieldDescriptor fd;
919 int length = this_oop->fields()->length();
920 for (int i = 0; i < length; i += next_offset) {
921 fd.initialize(this_oop(), i);
922 if (fd.is_static()) { f(&fd, CHECK); } // Do NOT remove {}! (CHECK macro expands into several statements)
923 }
924 }
925
926
927 static int compare_fields_by_offset(int* a, int* b) {
928 return a[0] - b[0];
929 }
930
931 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {
932 instanceKlass* super = superklass();
933 if (super != NULL) {
934 super->do_nonstatic_fields(cl);
935 }
936 fieldDescriptor fd;
937 int length = fields()->length();
938 // In DebugInfo nonstatic fields are sorted by offset.
939 int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1));
940 int j = 0;
941 for (int i = 0; i < length; i += next_offset) {
942 fd.initialize(as_klassOop(), i);
943 if (!fd.is_static()) {
944 fields_sorted[j + 0] = fd.offset();
945 fields_sorted[j + 1] = i;
946 j += 2;
947 }
948 }
949 if (j > 0) {
950 length = j;
951 // _sort_Fn is defined in growableArray.hpp.
952 qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
953 for (int i = 0; i < length; i += 2) {
954 fd.initialize(as_klassOop(), fields_sorted[i + 1]);
955 assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
956 cl->do_field(&fd);
957 }
958 }
959 FREE_C_HEAP_ARRAY(int, fields_sorted);
960 }
961
962
963 void instanceKlass::array_klasses_do(void f(klassOop k)) {
964 if (array_klasses() != NULL)
965 arrayKlass::cast(array_klasses())->array_klasses_do(f);
966 }
967
968
969 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {
970 f(as_klassOop());
971 array_klasses_do(f);
972 }
973
974 #ifdef ASSERT
975 static int linear_search(objArrayOop methods, Symbol* name, Symbol* signature) {
976 int len = methods->length();
977 for (int index = 0; index < len; index++) {
978 methodOop m = (methodOop)(methods->obj_at(index));
979 assert(m->is_method(), "must be method");
980 if (m->signature() == signature && m->name() == name) {
981 return index;
982 }
983 }
984 return -1;
985 }
986 #endif
987
988 methodOop instanceKlass::find_method(Symbol* name, Symbol* signature) const {
989 return instanceKlass::find_method(methods(), name, signature);
990 }
991
992 methodOop instanceKlass::find_method(objArrayOop methods, Symbol* name, Symbol* signature) {
993 int len = methods->length();
994 // methods are sorted, so do binary search
995 int l = 0;
996 int h = len - 1;
997 while (l <= h) {
998 int mid = (l + h) >> 1;
999 methodOop m = (methodOop)methods->obj_at(mid);
1000 assert(m->is_method(), "must be method");
1001 int res = m->name()->fast_compare(name);
1002 if (res == 0) {
1003 // found matching name; do linear search to find matching signature
1004 // first, quick check for common case
1005 if (m->signature() == signature) return m;
1006 // search downwards through overloaded methods
1007 int i;
1008 for (i = mid - 1; i >= l; i--) {
1009 methodOop m = (methodOop)methods->obj_at(i);
1010 assert(m->is_method(), "must be method");
1011 if (m->name() != name) break;
1012 if (m->signature() == signature) return m;
1013 }
1014 // search upwards
1015 for (i = mid + 1; i <= h; i++) {
1016 methodOop m = (methodOop)methods->obj_at(i);
1017 assert(m->is_method(), "must be method");
1018 if (m->name() != name) break;
1019 if (m->signature() == signature) return m;
1020 }
1021 // not found
1022 #ifdef ASSERT
1023 int index = linear_search(methods, name, signature);
1024 assert(index == -1, err_msg("binary search should have found entry %d", index));
1025 #endif
1026 return NULL;
1027 } else if (res < 0) {
1028 l = mid + 1;
1029 } else {
1030 h = mid - 1;
1031 }
1032 }
1033 #ifdef ASSERT
1034 int index = linear_search(methods, name, signature);
1035 assert(index == -1, err_msg("binary search should have found entry %d", index));
1036 #endif
1037 return NULL;
1038 }
1039
1040 methodOop instanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
1041 klassOop klass = as_klassOop();
1042 while (klass != NULL) {
1043 methodOop method = instanceKlass::cast(klass)->find_method(name, signature);
1044 if (method != NULL) return method;
1045 klass = instanceKlass::cast(klass)->super();
1046 }
1047 return NULL;
1048 }
1049
1050 // lookup a method in all the interfaces that this class implements
1051 methodOop instanceKlass::lookup_method_in_all_interfaces(Symbol* name,
1052 Symbol* signature) const {
1053 objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();
1054 int num_ifs = all_ifs->length();
1055 instanceKlass *ik = NULL;
1056 for (int i = 0; i < num_ifs; i++) {
1057 ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));
1058 methodOop m = ik->lookup_method(name, signature);
1059 if (m != NULL) {
1060 return m;
1061 }
1062 }
1063 return NULL;
1064 }
1065
1066 /* jni_id_for_impl for jfieldIds only */
1067 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
1068 MutexLocker ml(JfieldIdCreation_lock);
1069 // Retry lookup after we got the lock
1070 JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
1071 if (probe == NULL) {
1072 // Slow case, allocate new static field identifier
1073 probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());
1074 this_oop->set_jni_ids(probe);
1075 }
1076 return probe;
1077 }
1078
1079
1080 /* jni_id_for for jfieldIds only */
1081 JNIid* instanceKlass::jni_id_for(int offset) {
1082 JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1083 if (probe == NULL) {
1084 probe = jni_id_for_impl(this->as_klassOop(), offset);
1085 }
1086 return probe;
1087 }
1088
1089
1090 // Lookup or create a jmethodID.
1091 // This code is called by the VMThread and JavaThreads so the
1092 // locking has to be done very carefully to avoid deadlocks
1093 // and/or other cache consistency problems.
1094 //
1095 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
1096 size_t idnum = (size_t)method_h->method_idnum();
1097 jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1098 size_t length = 0;
1099 jmethodID id = NULL;
1100
1101 // We use a double-check locking idiom here because this cache is
1102 // performance sensitive. In the normal system, this cache only
1103 // transitions from NULL to non-NULL which is safe because we use
1104 // release_set_methods_jmethod_ids() to advertise the new cache.
1105 // A partially constructed cache should never be seen by a racing
1106 // thread. We also use release_store_ptr() to save a new jmethodID
1107 // in the cache so a partially constructed jmethodID should never be
1108 // seen either. Cache reads of existing jmethodIDs proceed without a
1109 // lock, but cache writes of a new jmethodID requires uniqueness and
1110 // creation of the cache itself requires no leaks so a lock is
1111 // generally acquired in those two cases.
1112 //
1113 // If the RedefineClasses() API has been used, then this cache can
1114 // grow and we'll have transitions from non-NULL to bigger non-NULL.
1115 // Cache creation requires no leaks and we require safety between all
1116 // cache accesses and freeing of the old cache so a lock is generally
1117 // acquired when the RedefineClasses() API has been used.
1118
1119 if (jmeths != NULL) {
1120 // the cache already exists
1121 if (!ik_h->idnum_can_increment()) {
1122 // the cache can't grow so we can just get the current values
1123 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1124 } else {
1125 // cache can grow so we have to be more careful
1126 if (Threads::number_of_threads() == 0 ||
1127 SafepointSynchronize::is_at_safepoint()) {
1128 // we're single threaded or at a safepoint - no locking needed
1129 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1130 } else {
1131 MutexLocker ml(JmethodIdCreation_lock);
1132 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1133 }
1134 }
1135 }
1136 // implied else:
1137 // we need to allocate a cache so default length and id values are good
1138
1139 if (jmeths == NULL || // no cache yet
1140 length <= idnum || // cache is too short
1141 id == NULL) { // cache doesn't contain entry
1142
1143 // This function can be called by the VMThread so we have to do all
1144 // things that might block on a safepoint before grabbing the lock.
1145 // Otherwise, we can deadlock with the VMThread or have a cache
1146 // consistency issue. These vars keep track of what we might have
1147 // to free after the lock is dropped.
1148 jmethodID to_dealloc_id = NULL;
1149 jmethodID* to_dealloc_jmeths = NULL;
1150
1151 // may not allocate new_jmeths or use it if we allocate it
1152 jmethodID* new_jmeths = NULL;
1153 if (length <= idnum) {
1154 // allocate a new cache that might be used
1155 size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
1156 new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);
1157 memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1158 // cache size is stored in element[0], other elements offset by one
1159 new_jmeths[0] = (jmethodID)size;
1160 }
1161
1162 // allocate a new jmethodID that might be used
1163 jmethodID new_id = NULL;
1164 if (method_h->is_old() && !method_h->is_obsolete()) {
1165 // The method passed in is old (but not obsolete), we need to use the current version
1166 methodOop current_method = ik_h->method_with_idnum((int)idnum);
1167 assert(current_method != NULL, "old and but not obsolete, so should exist");
1168 methodHandle current_method_h(current_method == NULL? method_h() : current_method);
1169 new_id = JNIHandles::make_jmethod_id(current_method_h);
1170 } else {
1171 // It is the current version of the method or an obsolete method,
1172 // use the version passed in
1173 new_id = JNIHandles::make_jmethod_id(method_h);
1174 }
1175
1176 if (Threads::number_of_threads() == 0 ||
1177 SafepointSynchronize::is_at_safepoint()) {
1178 // we're single threaded or at a safepoint - no locking needed
1179 id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1180 &to_dealloc_id, &to_dealloc_jmeths);
1181 } else {
1182 MutexLocker ml(JmethodIdCreation_lock);
1183 id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1184 &to_dealloc_id, &to_dealloc_jmeths);
1185 }
1186
1187 // The lock has been dropped so we can free resources.
1188 // Free up either the old cache or the new cache if we allocated one.
1189 if (to_dealloc_jmeths != NULL) {
1190 FreeHeap(to_dealloc_jmeths);
1191 }
1192 // free up the new ID since it wasn't needed
1193 if (to_dealloc_id != NULL) {
1194 JNIHandles::destroy_jmethod_id(to_dealloc_id);
1195 }
1196 }
1197 return id;
1198 }
1199
1200
1201 // Common code to fetch the jmethodID from the cache or update the
1202 // cache with the new jmethodID. This function should never do anything
1203 // that causes the caller to go to a safepoint or we can deadlock with
1204 // the VMThread or have cache consistency issues.
1205 //
1206 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
1207 instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
1208 jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1209 jmethodID** to_dealloc_jmeths_p) {
1210 assert(new_id != NULL, "sanity check");
1211 assert(to_dealloc_id_p != NULL, "sanity check");
1212 assert(to_dealloc_jmeths_p != NULL, "sanity check");
1213 assert(Threads::number_of_threads() == 0 ||
1214 SafepointSynchronize::is_at_safepoint() ||
1215 JmethodIdCreation_lock->owned_by_self(), "sanity check");
1216
1217 // reacquire the cache - we are locked, single threaded or at a safepoint
1218 jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1219 jmethodID id = NULL;
1220 size_t length = 0;
1221
1222 if (jmeths == NULL || // no cache yet
1223 (length = (size_t)jmeths[0]) <= idnum) { // cache is too short
1224 if (jmeths != NULL) {
1225 // copy any existing entries from the old cache
1226 for (size_t index = 0; index < length; index++) {
1227 new_jmeths[index+1] = jmeths[index+1];
1228 }
1229 *to_dealloc_jmeths_p = jmeths; // save old cache for later delete
1230 }
1231 ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
1232 } else {
1233 // fetch jmethodID (if any) from the existing cache
1234 id = jmeths[idnum+1];
1235 *to_dealloc_jmeths_p = new_jmeths; // save new cache for later delete
1236 }
1237 if (id == NULL) {
1238 // No matching jmethodID in the existing cache or we have a new
1239 // cache or we just grew the cache. This cache write is done here
1240 // by the first thread to win the foot race because a jmethodID
1241 // needs to be unique once it is generally available.
1242 id = new_id;
1243
1244 // The jmethodID cache can be read while unlocked so we have to
1245 // make sure the new jmethodID is complete before installing it
1246 // in the cache.
1247 OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1248 } else {
1249 *to_dealloc_id_p = new_id; // save new id for later delete
1250 }
1251 return id;
1252 }
1253
1254
1255 // Common code to get the jmethodID cache length and the jmethodID
1256 // value at index idnum if there is one.
1257 //
1258 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1259 size_t idnum, size_t *length_p, jmethodID* id_p) {
1260 assert(cache != NULL, "sanity check");
1261 assert(length_p != NULL, "sanity check");
1262 assert(id_p != NULL, "sanity check");
1263
1264 // cache size is stored in element[0], other elements offset by one
1265 *length_p = (size_t)cache[0];
1266 if (*length_p <= idnum) { // cache is too short
1267 *id_p = NULL;
1268 } else {
1269 *id_p = cache[idnum+1]; // fetch jmethodID (if any)
1270 }
1271 }
1272
1273
1274 // Lookup a jmethodID, NULL if not found. Do no blocking, no allocations, no handles
1275 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
1276 size_t idnum = (size_t)method->method_idnum();
1277 jmethodID* jmeths = methods_jmethod_ids_acquire();
1278 size_t length; // length assigned as debugging crumb
1279 jmethodID id = NULL;
1280 if (jmeths != NULL && // If there is a cache
1281 (length = (size_t)jmeths[0]) > idnum) { // and if it is long enough,
1282 id = jmeths[idnum+1]; // Look up the id (may be NULL)
1283 }
1284 return id;
1285 }
1286
1287
1288 // Cache an itable index
1289 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
1290 int* indices = methods_cached_itable_indices_acquire();
1291 int* to_dealloc_indices = NULL;
1292
1293 // We use a double-check locking idiom here because this cache is
1294 // performance sensitive. In the normal system, this cache only
1295 // transitions from NULL to non-NULL which is safe because we use
1296 // release_set_methods_cached_itable_indices() to advertise the
1297 // new cache. A partially constructed cache should never be seen
1298 // by a racing thread. Cache reads and writes proceed without a
1299 // lock, but creation of the cache itself requires no leaks so a
1300 // lock is generally acquired in that case.
1301 //
1302 // If the RedefineClasses() API has been used, then this cache can
1303 // grow and we'll have transitions from non-NULL to bigger non-NULL.
1304 // Cache creation requires no leaks and we require safety between all
1305 // cache accesses and freeing of the old cache so a lock is generally
1306 // acquired when the RedefineClasses() API has been used.
1307
1308 if (indices == NULL || idnum_can_increment()) {
1309 // we need a cache or the cache can grow
1310 MutexLocker ml(JNICachedItableIndex_lock);
1311 // reacquire the cache to see if another thread already did the work
1312 indices = methods_cached_itable_indices_acquire();
1313 size_t length = 0;
1314 // cache size is stored in element[0], other elements offset by one
1315 if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
1316 size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1317 int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);
1318 new_indices[0] = (int)size;
1319 // copy any existing entries
1320 size_t i;
1321 for (i = 0; i < length; i++) {
1322 new_indices[i+1] = indices[i+1];
1323 }
1324 // Set all the rest to -1
1325 for (i = length; i < size; i++) {
1326 new_indices[i+1] = -1;
1327 }
1328 if (indices != NULL) {
1329 // We have an old cache to delete so save it for after we
1330 // drop the lock.
1331 to_dealloc_indices = indices;
1332 }
1333 release_set_methods_cached_itable_indices(indices = new_indices);
1334 }
1335
1336 if (idnum_can_increment()) {
1337 // this cache can grow so we have to write to it safely
1338 indices[idnum+1] = index;
1339 }
1340 } else {
1341 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
1342 }
1343
1344 if (!idnum_can_increment()) {
1345 // The cache cannot grow and this JNI itable index value does not
1346 // have to be unique like a jmethodID. If there is a race to set it,
1347 // it doesn't matter.
1348 indices[idnum+1] = index;
1349 }
1350
1351 if (to_dealloc_indices != NULL) {
1352 // we allocated a new cache so free the old one
1353 FreeHeap(to_dealloc_indices);
1354 }
1355 }
1356
1357
1358 // Retrieve a cached itable index
1359 int instanceKlass::cached_itable_index(size_t idnum) {
1360 int* indices = methods_cached_itable_indices_acquire();
1361 if (indices != NULL && ((size_t)indices[0]) > idnum) {
1362 // indices exist and are long enough, retrieve possible cached
1363 return indices[idnum+1];
1364 }
1365 return -1;
1366 }
1367
1368
1369 //
1370 // nmethodBucket is used to record dependent nmethods for
1371 // deoptimization. nmethod dependencies are actually <klass, method>
1372 // pairs but we really only care about the klass part for purposes of
1373 // finding nmethods which might need to be deoptimized. Instead of
1374 // recording the method, a count of how many times a particular nmethod
1375 // was recorded is kept. This ensures that any recording errors are
1376 // noticed since an nmethod should be removed as many times are it's
1377 // added.
1378 //
1379 class nmethodBucket {
1380 private:
1381 nmethod* _nmethod;
1382 int _count;
1383 nmethodBucket* _next;
1384
1385 public:
1386 nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1387 _nmethod = nmethod;
1388 _next = next;
1389 _count = 1;
1390 }
1391 int count() { return _count; }
1392 int increment() { _count += 1; return _count; }
1393 int decrement() { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
1394 nmethodBucket* next() { return _next; }
1395 void set_next(nmethodBucket* b) { _next = b; }
1396 nmethod* get_nmethod() { return _nmethod; }
1397 };
1398
1399
1400 //
1401 // Walk the list of dependent nmethods searching for nmethods which
1402 // are dependent on the klassOop that was passed in and mark them for
1403 // deoptimization. Returns the number of nmethods found.
1404 //
1405 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
1406 assert_locked_or_safepoint(CodeCache_lock);
1407 int found = 0;
1408 nmethodBucket* b = _dependencies;
1409 while (b != NULL) {
1410 nmethod* nm = b->get_nmethod();
1411 // since dependencies aren't removed until an nmethod becomes a zombie,
1412 // the dependency list may contain nmethods which aren't alive.
1413 if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
1414 if (TraceDependencies) {
1415 ResourceMark rm;
1416 tty->print_cr("Marked for deoptimization");
1417 tty->print_cr(" context = %s", this->external_name());
1418 changes.print();
1419 nm->print();
1420 nm->print_dependencies();
1421 }
1422 nm->mark_for_deoptimization();
1423 found++;
1424 }
1425 b = b->next();
1426 }
1427 return found;
1428 }
1429
1430
1431 //
1432 // Add an nmethodBucket to the list of dependencies for this nmethod.
1433 // It's possible that an nmethod has multiple dependencies on this klass
1434 // so a count is kept for each bucket to guarantee that creation and
1435 // deletion of dependencies is consistent.
1436 //
1437 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
1438 assert_locked_or_safepoint(CodeCache_lock);
1439 nmethodBucket* b = _dependencies;
1440 nmethodBucket* last = NULL;
1441 while (b != NULL) {
1442 if (nm == b->get_nmethod()) {
1443 b->increment();
1444 return;
1445 }
1446 b = b->next();
1447 }
1448 _dependencies = new nmethodBucket(nm, _dependencies);
1449 }
1450
1451
1452 //
1453 // Decrement count of the nmethod in the dependency list and remove
1454 // the bucket competely when the count goes to 0. This method must
1455 // find a corresponding bucket otherwise there's a bug in the
1456 // recording of dependecies.
1457 //
1458 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
1459 assert_locked_or_safepoint(CodeCache_lock);
1460 nmethodBucket* b = _dependencies;
1461 nmethodBucket* last = NULL;
1462 while (b != NULL) {
1463 if (nm == b->get_nmethod()) {
1464 if (b->decrement() == 0) {
1465 if (last == NULL) {
1466 _dependencies = b->next();
1467 } else {
1468 last->set_next(b->next());
1469 }
1470 delete b;
1471 }
1472 return;
1473 }
1474 last = b;
1475 b = b->next();
1476 }
1477 #ifdef ASSERT
1478 tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
1479 nm->print();
1480 #endif // ASSERT
1481 ShouldNotReachHere();
1482 }
1483
1484
1485 #ifndef PRODUCT
1486 void instanceKlass::print_dependent_nmethods(bool verbose) {
1487 nmethodBucket* b = _dependencies;
1488 int idx = 0;
1489 while (b != NULL) {
1490 nmethod* nm = b->get_nmethod();
1491 tty->print("[%d] count=%d { ", idx++, b->count());
1492 if (!verbose) {
1493 nm->print_on(tty, "nmethod");
1494 tty->print_cr(" } ");
1495 } else {
1496 nm->print();
1497 nm->print_dependencies();
1498 tty->print_cr("--- } ");
1499 }
1500 b = b->next();
1501 }
1502 }
1503
1504
1505 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
1506 nmethodBucket* b = _dependencies;
1507 while (b != NULL) {
1508 if (nm == b->get_nmethod()) {
1509 return true;
1510 }
1511 b = b->next();
1512 }
1513 return false;
1514 }
1515 #endif //PRODUCT
1516
1517
1518 #ifdef ASSERT
1519 template <class T> void assert_is_in(T *p) {
1520 T heap_oop = oopDesc::load_heap_oop(p);
1521 if (!oopDesc::is_null(heap_oop)) {
1522 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1523 assert(Universe::heap()->is_in(o), "should be in heap");
1524 }
1525 }
1526 template <class T> void assert_is_in_closed_subset(T *p) {
1527 T heap_oop = oopDesc::load_heap_oop(p);
1528 if (!oopDesc::is_null(heap_oop)) {
1529 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1530 assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
1531 }
1532 }
1533 template <class T> void assert_is_in_reserved(T *p) {
1534 T heap_oop = oopDesc::load_heap_oop(p);
1535 if (!oopDesc::is_null(heap_oop)) {
1536 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1537 assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
1538 }
1539 }
1540 template <class T> void assert_nothing(T *p) {}
1541
1542 #else
1543 template <class T> void assert_is_in(T *p) {}
1544 template <class T> void assert_is_in_closed_subset(T *p) {}
1545 template <class T> void assert_is_in_reserved(T *p) {}
1546 template <class T> void assert_nothing(T *p) {}
1547 #endif // ASSERT
1548
1549 //
1550 // Macros that iterate over areas of oops which are specialized on type of
1551 // oop pointer either narrow or wide, depending on UseCompressedOops
1552 //
1553 // Parameters are:
1554 // T - type of oop to point to (either oop or narrowOop)
1555 // start_p - starting pointer for region to iterate over
1556 // count - number of oops or narrowOops to iterate over
1557 // do_oop - action to perform on each oop (it's arbitrary C code which
1558 // makes it more efficient to put in a macro rather than making
1559 // it a template function)
1560 // assert_fn - assert function which is template function because performance
1561 // doesn't matter when enabled.
1562 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
1563 T, start_p, count, do_oop, \
1564 assert_fn) \
1565 { \
1566 T* p = (T*)(start_p); \
1567 T* const end = p + (count); \
1568 while (p < end) { \
1569 (assert_fn)(p); \
1570 do_oop; \
1571 ++p; \
1572 } \
1573 }
1574
1575 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
1576 T, start_p, count, do_oop, \
1577 assert_fn) \
1578 { \
1579 T* const start = (T*)(start_p); \
1580 T* p = start + (count); \
1581 while (start < p) { \
1582 --p; \
1583 (assert_fn)(p); \
1584 do_oop; \
1585 } \
1586 }
1587
1588 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
1589 T, start_p, count, low, high, \
1590 do_oop, assert_fn) \
1591 { \
1592 T* const l = (T*)(low); \
1593 T* const h = (T*)(high); \
1594 assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
1595 mask_bits((intptr_t)h, sizeof(T)-1) == 0, \
1596 "bounded region must be properly aligned"); \
1597 T* p = (T*)(start_p); \
1598 T* end = p + (count); \
1599 if (p < l) p = l; \
1600 if (end > h) end = h; \
1601 while (p < end) { \
1602 (assert_fn)(p); \
1603 do_oop; \
1604 ++p; \
1605 } \
1606 }
1607
1608
1609 // The following macros call specialized macros, passing either oop or
1610 // narrowOop as the specialization type. These test the UseCompressedOops
1611 // flag.
1612 #define InstanceKlass_OOP_ITERATE(start_p, count, \
1613 do_oop, assert_fn) \
1614 { \
1615 if (UseCompressedOops) { \
1616 InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
1617 start_p, count, \
1618 do_oop, assert_fn) \
1619 } else { \
1620 InstanceKlass_SPECIALIZED_OOP_ITERATE(oop, \
1621 start_p, count, \
1622 do_oop, assert_fn) \
1623 } \
1624 }
1625
1626 #define InstanceKlass_BOUNDED_OOP_ITERATE(start_p, count, low, high, \
1627 do_oop, assert_fn) \
1628 { \
1629 if (UseCompressedOops) { \
1630 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
1631 start_p, count, \
1632 low, high, \
1633 do_oop, assert_fn) \
1634 } else { \
1635 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop, \
1636 start_p, count, \
1637 low, high, \
1638 do_oop, assert_fn) \
1639 } \
1640 }
1641
1642 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn) \
1643 { \
1644 /* Compute oopmap block range. The common case \
1645 is nonstatic_oop_map_size == 1. */ \
1646 OopMapBlock* map = start_of_nonstatic_oop_maps(); \
1647 OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \
1648 if (UseCompressedOops) { \
1649 while (map < end_map) { \
1650 InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
1651 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1652 do_oop, assert_fn) \
1653 ++map; \
1654 } \
1655 } else { \
1656 while (map < end_map) { \
1657 InstanceKlass_SPECIALIZED_OOP_ITERATE(oop, \
1658 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1659 do_oop, assert_fn) \
1660 ++map; \
1661 } \
1662 } \
1663 }
1664
1665 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn) \
1666 { \
1667 OopMapBlock* const start_map = start_of_nonstatic_oop_maps(); \
1668 OopMapBlock* map = start_map + nonstatic_oop_map_count(); \
1669 if (UseCompressedOops) { \
1670 while (start_map < map) { \
1671 --map; \
1672 InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop, \
1673 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1674 do_oop, assert_fn) \
1675 } \
1676 } else { \
1677 while (start_map < map) { \
1678 --map; \
1679 InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop, \
1680 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1681 do_oop, assert_fn) \
1682 } \
1683 } \
1684 }
1685
1686 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop, \
1687 assert_fn) \
1688 { \
1689 /* Compute oopmap block range. The common case is \
1690 nonstatic_oop_map_size == 1, so we accept the \
1691 usually non-existent extra overhead of examining \
1692 all the maps. */ \
1693 OopMapBlock* map = start_of_nonstatic_oop_maps(); \
1694 OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \
1695 if (UseCompressedOops) { \
1696 while (map < end_map) { \
1697 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
1698 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1699 low, high, \
1700 do_oop, assert_fn) \
1701 ++map; \
1702 } \
1703 } else { \
1704 while (map < end_map) { \
1705 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop, \
1706 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1707 low, high, \
1708 do_oop, assert_fn) \
1709 ++map; \
1710 } \
1711 } \
1712 }
1713
1714 void instanceKlass::follow_static_fields() {
1715 InstanceKlass_OOP_ITERATE( \
1716 start_of_static_fields(), static_oop_field_size(), \
1717 MarkSweep::mark_and_push(p), \
1718 assert_is_in_closed_subset)
1719 }
1720
1721 #ifndef SERIALGC
1722 void instanceKlass::follow_static_fields(ParCompactionManager* cm) {
1723 InstanceKlass_OOP_ITERATE( \
1724 start_of_static_fields(), static_oop_field_size(), \
1725 PSParallelCompact::mark_and_push(cm, p), \
1726 assert_is_in)
1727 }
1728 #endif // SERIALGC
1729
1730 void instanceKlass::adjust_static_fields() {
1731 InstanceKlass_OOP_ITERATE( \
1732 start_of_static_fields(), static_oop_field_size(), \
1733 MarkSweep::adjust_pointer(p), \
1734 assert_nothing)
1735 }
1736
1737 #ifndef SERIALGC
1738 void instanceKlass::update_static_fields() {
1739 InstanceKlass_OOP_ITERATE( \
1740 start_of_static_fields(), static_oop_field_size(), \
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 void instanceKlass::push_static_fields(PSPromotionManager* pm) {
1877 InstanceKlass_OOP_ITERATE( \
1878 start_of_static_fields(), static_oop_field_size(), \
1879 if (PSScavenge::should_scavenge(p)) { \
1880 pm->claim_or_forward_depth(p); \
1881 }, \
1882 assert_nothing )
1883 }
1884
1885 void instanceKlass::copy_static_fields(ParCompactionManager* cm) {
1886 InstanceKlass_OOP_ITERATE( \
1887 start_of_static_fields(), static_oop_field_size(), \
1888 PSParallelCompact::adjust_pointer(p), \
1889 assert_is_in)
1890 }
1891 #endif // SERIALGC
1892
1893 // This klass is alive but the implementor link is not followed/updated.
1894 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
1895
1896 void instanceKlass::follow_weak_klass_links(
1897 BoolObjectClosure* is_alive, OopClosure* keep_alive) {
1898 assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
1899 if (ClassUnloading) {
1900 for (int i = 0; i < implementors_limit; i++) {
1901 klassOop impl = _implementors[i];
1902 if (impl == NULL) break; // no more in the list
1903 if (!is_alive->do_object_b(impl)) {
1904 // remove this guy from the list by overwriting him with the tail
1905 int lasti = --_nof_implementors;
1906 assert(lasti >= i && lasti < implementors_limit, "just checking");
1907 _implementors[i] = _implementors[lasti];
1908 _implementors[lasti] = NULL;
1909 --i; // rerun the loop at this index
1910 }
1911 }
1912 } else {
1913 for (int i = 0; i < implementors_limit; i++) {
1914 keep_alive->do_oop(&adr_implementors()[i]);
1915 }
1916 }
1917 Klass::follow_weak_klass_links(is_alive, keep_alive);
1918 }
1919
1920 void instanceKlass::remove_unshareable_info() {
1921 Klass::remove_unshareable_info();
1922 init_implementor();
1923 }
1924
1925 static void clear_all_breakpoints(methodOop m) {
1926 m->clear_all_breakpoints();
1927 }
1928
1929 void instanceKlass::release_C_heap_structures() {
1930 // Deallocate oop map cache
1931 if (_oop_map_cache != NULL) {
1932 delete _oop_map_cache;
1933 _oop_map_cache = NULL;
1934 }
1935
1936 // Deallocate JNI identifiers for jfieldIDs
1937 JNIid::deallocate(jni_ids());
1938 set_jni_ids(NULL);
1939
1940 jmethodID* jmeths = methods_jmethod_ids_acquire();
1941 if (jmeths != (jmethodID*)NULL) {
1942 release_set_methods_jmethod_ids(NULL);
1943 FreeHeap(jmeths);
1944 }
1945
1946 int* indices = methods_cached_itable_indices_acquire();
1947 if (indices != (int*)NULL) {
1948 release_set_methods_cached_itable_indices(NULL);
1949 FreeHeap(indices);
1950 }
1951
1952 // release dependencies
1953 nmethodBucket* b = _dependencies;
1954 _dependencies = NULL;
1955 while (b != NULL) {
1956 nmethodBucket* next = b->next();
1957 delete b;
1958 b = next;
1959 }
1960
1961 // Deallocate breakpoint records
1962 if (breakpoints() != 0x0) {
1963 methods_do(clear_all_breakpoints);
1964 assert(breakpoints() == 0x0, "should have cleared breakpoints");
1965 }
1966
1967 // deallocate information about previous versions
1968 if (_previous_versions != NULL) {
1969 for (int i = _previous_versions->length() - 1; i >= 0; i--) {
1970 PreviousVersionNode * pv_node = _previous_versions->at(i);
1971 delete pv_node;
1972 }
1973 delete _previous_versions;
1974 _previous_versions = NULL;
1975 }
1976
1977 // deallocate the cached class file
1978 if (_cached_class_file_bytes != NULL) {
1979 os::free(_cached_class_file_bytes);
1980 _cached_class_file_bytes = NULL;
1981 _cached_class_file_len = 0;
1982 }
1983
1984 // Decrement symbol reference counts associated with the unloaded class.
1985 if (_name != NULL) _name->decrement_refcount();
1986 // unreference array name derived from this class name (arrays of an unloaded
1987 // class can't be referenced anymore).
1988 if (_array_name != NULL) _array_name->decrement_refcount();
1989 if (_source_file_name != NULL) _source_file_name->decrement_refcount();
1990 if (_source_debug_extension != NULL) _source_debug_extension->decrement_refcount();
1991 // walk constant pool and decrement symbol reference counts
1992 _constants->unreference_symbols();
1993 }
1994
1995 void instanceKlass::set_source_file_name(Symbol* n) {
1996 _source_file_name = n;
1997 if (_source_file_name != NULL) _source_file_name->increment_refcount();
1998 }
1999
2000 void instanceKlass::set_source_debug_extension(Symbol* n) {
2001 _source_debug_extension = n;
2002 if (_source_debug_extension != NULL) _source_debug_extension->increment_refcount();
2003 }
2004
2005 const char* instanceKlass::signature_name() const {
2006 const char* src = (const char*) (name()->as_C_string());
2007 const int src_length = (int)strlen(src);
2008 char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
2009 int src_index = 0;
2010 int dest_index = 0;
2011 dest[dest_index++] = 'L';
2012 while (src_index < src_length) {
2013 dest[dest_index++] = src[src_index++];
2014 }
2015 dest[dest_index++] = ';';
2016 dest[dest_index] = '\0';
2017 return dest;
2018 }
2019
2020 // different verisons of is_same_class_package
2021 bool instanceKlass::is_same_class_package(klassOop class2) {
2022 klassOop class1 = as_klassOop();
2023 oop classloader1 = instanceKlass::cast(class1)->class_loader();
2024 Symbol* classname1 = Klass::cast(class1)->name();
2025
2026 if (Klass::cast(class2)->oop_is_objArray()) {
2027 class2 = objArrayKlass::cast(class2)->bottom_klass();
2028 }
2029 oop classloader2;
2030 if (Klass::cast(class2)->oop_is_instance()) {
2031 classloader2 = instanceKlass::cast(class2)->class_loader();
2032 } else {
2033 assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
2034 classloader2 = NULL;
2035 }
2036 Symbol* classname2 = Klass::cast(class2)->name();
2037
2038 return instanceKlass::is_same_class_package(classloader1, classname1,
2039 classloader2, classname2);
2040 }
2041
2042 bool instanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
2043 klassOop class1 = as_klassOop();
2044 oop classloader1 = instanceKlass::cast(class1)->class_loader();
2045 Symbol* classname1 = Klass::cast(class1)->name();
2046
2047 return instanceKlass::is_same_class_package(classloader1, classname1,
2048 classloader2, classname2);
2049 }
2050
2051 // return true if two classes are in the same package, classloader
2052 // and classname information is enough to determine a class's package
2053 bool instanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
2054 oop class_loader2, Symbol* class_name2) {
2055 if (class_loader1 != class_loader2) {
2056 return false;
2057 } else if (class_name1 == class_name2) {
2058 return true; // skip painful bytewise comparison
2059 } else {
2060 ResourceMark rm;
2061
2062 // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
2063 // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
2064 // Otherwise, we just compare jbyte values between the strings.
2065 const jbyte *name1 = class_name1->base();
2066 const jbyte *name2 = class_name2->base();
2067
2068 const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
2069 const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
2070
2071 if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
2072 // One of the two doesn't have a package. Only return true
2073 // if the other one also doesn't have a package.
2074 return last_slash1 == last_slash2;
2075 } else {
2076 // Skip over '['s
2077 if (*name1 == '[') {
2078 do {
2079 name1++;
2080 } while (*name1 == '[');
2081 if (*name1 != 'L') {
2082 // Something is terribly wrong. Shouldn't be here.
2083 return false;
2084 }
2085 }
2086 if (*name2 == '[') {
2087 do {
2088 name2++;
2089 } while (*name2 == '[');
2090 if (*name2 != 'L') {
2091 // Something is terribly wrong. Shouldn't be here.
2092 return false;
2093 }
2094 }
2095
2096 // Check that package part is identical
2097 int length1 = last_slash1 - name1;
2098 int length2 = last_slash2 - name2;
2099
2100 return UTF8::equal(name1, length1, name2, length2);
2101 }
2102 }
2103 }
2104
2105 // Returns true iff super_method can be overridden by a method in targetclassname
2106 // See JSL 3rd edition 8.4.6.1
2107 // Assumes name-signature match
2108 // "this" is instanceKlass of super_method which must exist
2109 // note that the instanceKlass of the method in the targetclassname has not always been created yet
2110 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2111 // Private methods can not be overridden
2112 if (super_method->is_private()) {
2113 return false;
2114 }
2115 // If super method is accessible, then override
2116 if ((super_method->is_protected()) ||
2117 (super_method->is_public())) {
2118 return true;
2119 }
2120 // Package-private methods are not inherited outside of package
2121 assert(super_method->is_package_private(), "must be package private");
2122 return(is_same_class_package(targetclassloader(), targetclassname));
2123 }
2124
2125 /* defined for now in jvm.cpp, for historical reasons *--
2126 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
2127 Symbol*& simple_name_result, TRAPS) {
2128 ...
2129 }
2130 */
2131
2132 // tell if two classes have the same enclosing class (at package level)
2133 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
2134 klassOop class2_oop, TRAPS) {
2135 if (class2_oop == class1->as_klassOop()) return true;
2136 if (!Klass::cast(class2_oop)->oop_is_instance()) return false;
2137 instanceKlassHandle class2(THREAD, class2_oop);
2138
2139 // must be in same package before we try anything else
2140 if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
2141 return false;
2142
2143 // As long as there is an outer1.getEnclosingClass,
2144 // shift the search outward.
2145 instanceKlassHandle outer1 = class1;
2146 for (;;) {
2147 // As we walk along, look for equalities between outer1 and class2.
2148 // Eventually, the walks will terminate as outer1 stops
2149 // at the top-level class around the original class.
2150 bool ignore_inner_is_member;
2151 klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
2152 CHECK_false);
2153 if (next == NULL) break;
2154 if (next == class2()) return true;
2155 outer1 = instanceKlassHandle(THREAD, next);
2156 }
2157
2158 // Now do the same for class2.
2159 instanceKlassHandle outer2 = class2;
2160 for (;;) {
2161 bool ignore_inner_is_member;
2162 klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2163 CHECK_false);
2164 if (next == NULL) break;
2165 // Might as well check the new outer against all available values.
2166 if (next == class1()) return true;
2167 if (next == outer1()) return true;
2168 outer2 = instanceKlassHandle(THREAD, next);
2169 }
2170
2171 // If by this point we have not found an equality between the
2172 // two classes, we know they are in separate package members.
2173 return false;
2174 }
2175
2176
2177 jint instanceKlass::compute_modifier_flags(TRAPS) const {
2178 klassOop k = as_klassOop();
2179 jint access = access_flags().as_int();
2180
2181 // But check if it happens to be member class.
2182 typeArrayOop inner_class_list = inner_classes();
2183 int length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
2184 assert (length % instanceKlass::inner_class_next_offset == 0, "just checking");
2185 if (length > 0) {
2186 typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
2187 instanceKlassHandle ik(THREAD, k);
2188 for (int i = 0; i < length; i += instanceKlass::inner_class_next_offset) {
2189 int ioff = inner_class_list_h->ushort_at(
2190 i + instanceKlass::inner_class_inner_class_info_offset);
2191
2192 // Inner class attribute can be zero, skip it.
2193 // Strange but true: JVM spec. allows null inner class refs.
2194 if (ioff == 0) continue;
2195
2196 // only look at classes that are already loaded
2197 // since we are looking for the flags for our self.
2198 Symbol* inner_name = ik->constants()->klass_name_at(ioff);
2199 if ((ik->name() == inner_name)) {
2200 // This is really a member class.
2201 access = inner_class_list_h->ushort_at(i + instanceKlass::inner_class_access_flags_offset);
2202 break;
2203 }
2204 }
2205 }
2206 // Remember to strip ACC_SUPER bit
2207 return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2208 }
2209
2210 jint instanceKlass::jvmti_class_status() const {
2211 jint result = 0;
2212
2213 if (is_linked()) {
2214 result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2215 }
2216
2217 if (is_initialized()) {
2218 assert(is_linked(), "Class status is not consistent");
2219 result |= JVMTI_CLASS_STATUS_INITIALIZED;
2220 }
2221 if (is_in_error_state()) {
2222 result |= JVMTI_CLASS_STATUS_ERROR;
2223 }
2224 return result;
2225 }
2226
2227 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
2228 itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2229 int method_table_offset_in_words = ioe->offset()/wordSize;
2230 int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2231 / itableOffsetEntry::size();
2232
2233 for (int cnt = 0 ; ; cnt ++, ioe ++) {
2234 // If the interface isn't implemented by the receiver class,
2235 // the VM should throw IncompatibleClassChangeError.
2236 if (cnt >= nof_interfaces) {
2237 THROW_0(vmSymbols::java_lang_IncompatibleClassChangeError());
2238 }
2239
2240 klassOop ik = ioe->interface_klass();
2241 if (ik == holder) break;
2242 }
2243
2244 itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
2245 methodOop m = ime[index].method();
2246 if (m == NULL) {
2247 THROW_0(vmSymbols::java_lang_AbstractMethodError());
2248 }
2249 return m;
2250 }
2251
2252 // On-stack replacement stuff
2253 void instanceKlass::add_osr_nmethod(nmethod* n) {
2254 // only one compilation can be active
2255 NEEDS_CLEANUP
2256 // This is a short non-blocking critical region, so the no safepoint check is ok.
2257 OsrList_lock->lock_without_safepoint_check();
2258 assert(n->is_osr_method(), "wrong kind of nmethod");
2259 n->set_osr_link(osr_nmethods_head());
2260 set_osr_nmethods_head(n);
2261 // Raise the highest osr level if necessary
2262 if (TieredCompilation) {
2263 methodOop m = n->method();
2264 m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2265 }
2266 // Remember to unlock again
2267 OsrList_lock->unlock();
2268
2269 // Get rid of the osr methods for the same bci that have lower levels.
2270 if (TieredCompilation) {
2271 for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2272 nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2273 if (inv != NULL && inv->is_in_use()) {
2274 inv->make_not_entrant();
2275 }
2276 }
2277 }
2278 }
2279
2280
2281 void instanceKlass::remove_osr_nmethod(nmethod* n) {
2282 // This is a short non-blocking critical region, so the no safepoint check is ok.
2283 OsrList_lock->lock_without_safepoint_check();
2284 assert(n->is_osr_method(), "wrong kind of nmethod");
2285 nmethod* last = NULL;
2286 nmethod* cur = osr_nmethods_head();
2287 int max_level = CompLevel_none; // Find the max comp level excluding n
2288 methodOop m = n->method();
2289 // Search for match
2290 while(cur != NULL && cur != n) {
2291 if (TieredCompilation) {
2292 // Find max level before n
2293 max_level = MAX2(max_level, cur->comp_level());
2294 }
2295 last = cur;
2296 cur = cur->osr_link();
2297 }
2298 nmethod* next = NULL;
2299 if (cur == n) {
2300 next = cur->osr_link();
2301 if (last == NULL) {
2302 // Remove first element
2303 set_osr_nmethods_head(next);
2304 } else {
2305 last->set_osr_link(next);
2306 }
2307 }
2308 n->set_osr_link(NULL);
2309 if (TieredCompilation) {
2310 cur = next;
2311 while (cur != NULL) {
2312 // Find max level after n
2313 max_level = MAX2(max_level, cur->comp_level());
2314 cur = cur->osr_link();
2315 }
2316 m->set_highest_osr_comp_level(max_level);
2317 }
2318 // Remember to unlock again
2319 OsrList_lock->unlock();
2320 }
2321
2322 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
2323 // This is a short non-blocking critical region, so the no safepoint check is ok.
2324 OsrList_lock->lock_without_safepoint_check();
2325 nmethod* osr = osr_nmethods_head();
2326 nmethod* best = NULL;
2327 while (osr != NULL) {
2328 assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2329 // There can be a time when a c1 osr method exists but we are waiting
2330 // for a c2 version. When c2 completes its osr nmethod we will trash
2331 // the c1 version and only be able to find the c2 version. However
2332 // while we overflow in the c1 code at back branches we don't want to
2333 // try and switch to the same code as we are already running
2334
2335 if (osr->method() == m &&
2336 (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2337 if (match_level) {
2338 if (osr->comp_level() == comp_level) {
2339 // Found a match - return it.
2340 OsrList_lock->unlock();
2341 return osr;
2342 }
2343 } else {
2344 if (best == NULL || (osr->comp_level() > best->comp_level())) {
2345 if (osr->comp_level() == CompLevel_highest_tier) {
2346 // Found the best possible - return it.
2347 OsrList_lock->unlock();
2348 return osr;
2349 }
2350 best = osr;
2351 }
2352 }
2353 }
2354 osr = osr->osr_link();
2355 }
2356 OsrList_lock->unlock();
2357 if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2358 return best;
2359 }
2360 return NULL;
2361 }
2362
2363 // -----------------------------------------------------------------------------------------------------
2364 #ifndef PRODUCT
2365
2366 // Printing
2367
2368 #define BULLET " - "
2369
2370 void FieldPrinter::do_field(fieldDescriptor* fd) {
2371 _st->print(BULLET);
2372 if (fd->is_static() || (_obj == NULL)) {
2373 fd->print_on(_st);
2374 _st->cr();
2375 } else {
2376 fd->print_on_for(_st, _obj);
2377 _st->cr();
2378 }
2379 }
2380
2381
2382 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
2383 Klass::oop_print_on(obj, st);
2384
2385 if (as_klassOop() == SystemDictionary::String_klass()) {
2386 typeArrayOop value = java_lang_String::value(obj);
2387 juint offset = java_lang_String::offset(obj);
2388 juint length = java_lang_String::length(obj);
2389 if (value != NULL &&
2390 value->is_typeArray() &&
2391 offset <= (juint) value->length() &&
2392 offset + length <= (juint) value->length()) {
2393 st->print(BULLET"string: ");
2394 Handle h_obj(obj);
2395 java_lang_String::print(h_obj, st);
2396 st->cr();
2397 if (!WizardMode) return; // that is enough
2398 }
2399 }
2400
2401 st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2402 FieldPrinter print_nonstatic_field(st, obj);
2403 do_nonstatic_fields(&print_nonstatic_field);
2404
2405 if (as_klassOop() == SystemDictionary::Class_klass()) {
2406 st->print(BULLET"signature: ");
2407 java_lang_Class::print_signature(obj, st);
2408 st->cr();
2409 klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
2410 st->print(BULLET"fake entry for mirror: ");
2411 mirrored_klass->print_value_on(st);
2412 st->cr();
2413 st->print(BULLET"fake entry resolved_constructor: ");
2414 methodOop ctor = java_lang_Class::resolved_constructor(obj);
2415 ctor->print_value_on(st);
2416 klassOop array_klass = java_lang_Class::array_klass(obj);
2417 st->cr();
2418 st->print(BULLET"fake entry for array: ");
2419 array_klass->print_value_on(st);
2420 st->cr();
2421 } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2422 st->print(BULLET"signature: ");
2423 java_dyn_MethodType::print_signature(obj, st);
2424 st->cr();
2425 }
2426 }
2427
2428 #endif //PRODUCT
2429
2430 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
2431 st->print("a ");
2432 name()->print_value_on(st);
2433 obj->print_address_on(st);
2434 if (as_klassOop() == SystemDictionary::String_klass()
2435 && java_lang_String::value(obj) != NULL) {
2436 ResourceMark rm;
2437 int len = java_lang_String::length(obj);
2438 int plen = (len < 24 ? len : 12);
2439 char* str = java_lang_String::as_utf8_string(obj, 0, plen);
2440 st->print(" = \"%s\"", str);
2441 if (len > plen)
2442 st->print("...[%d]", len);
2443 } else if (as_klassOop() == SystemDictionary::Class_klass()) {
2444 klassOop k = java_lang_Class::as_klassOop(obj);
2445 st->print(" = ");
2446 if (k != NULL) {
2447 k->print_value_on(st);
2448 } else {
2449 const char* tname = type2name(java_lang_Class::primitive_type(obj));
2450 st->print("%s", tname ? tname : "type?");
2451 }
2452 } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2453 st->print(" = ");
2454 java_dyn_MethodType::print_signature(obj, st);
2455 } else if (java_lang_boxing_object::is_instance(obj)) {
2456 st->print(" = ");
2457 java_lang_boxing_object::print(obj, st);
2458 }
2459 }
2460
2461 const char* instanceKlass::internal_name() const {
2462 return external_name();
2463 }
2464
2465 // Verification
2466
2467 class VerifyFieldClosure: public OopClosure {
2468 protected:
2469 template <class T> void do_oop_work(T* p) {
2470 guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
2471 oop obj = oopDesc::load_decode_heap_oop(p);
2472 if (!obj->is_oop_or_null()) {
2473 tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
2474 Universe::print();
2475 guarantee(false, "boom");
2476 }
2477 }
2478 public:
2479 virtual void do_oop(oop* p) { VerifyFieldClosure::do_oop_work(p); }
2480 virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
2481 };
2482
2483 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
2484 Klass::oop_verify_on(obj, st);
2485 VerifyFieldClosure blk;
2486 oop_oop_iterate(obj, &blk);
2487 }
2488
2489 #ifndef PRODUCT
2490
2491 void instanceKlass::verify_class_klass_nonstatic_oop_maps(klassOop k) {
2492 // This verification code is disabled. JDK_Version::is_gte_jdk14x_version()
2493 // cannot be called since this function is called before the VM is
2494 // able to determine what JDK version is running with.
2495 // The check below always is false since 1.4.
2496 return;
2497
2498 // This verification code temporarily disabled for the 1.4
2499 // reflection implementation since java.lang.Class now has
2500 // Java-level instance fields. Should rewrite this to handle this
2501 // case.
2502 if (!(JDK_Version::is_gte_jdk14x_version() && UseNewReflection)) {
2503 // Verify that java.lang.Class instances have a fake oop field added.
2504 instanceKlass* ik = instanceKlass::cast(k);
2505
2506 // Check that we have the right class
2507 static bool first_time = true;
2508 guarantee(k == SystemDictionary::Class_klass() && first_time, "Invalid verify of maps");
2509 first_time = false;
2510 const int extra = java_lang_Class::number_of_fake_oop_fields;
2511 guarantee(ik->nonstatic_field_size() == extra, "just checking");
2512 guarantee(ik->nonstatic_oop_map_count() == 1, "just checking");
2513 guarantee(ik->size_helper() == align_object_size(instanceOopDesc::header_size() + extra), "just checking");
2514
2515 // Check that the map is (2,extra)
2516 int offset = java_lang_Class::klass_offset;
2517
2518 OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
2519 guarantee(map->offset() == offset && map->count() == (unsigned int) extra,
2520 "sanity");
2521 }
2522 }
2523
2524 #endif // ndef PRODUCT
2525
2526 // JNIid class for jfieldIDs only
2527 // Note to reviewers:
2528 // These JNI functions are just moved over to column 1 and not changed
2529 // in the compressed oops workspace.
2530 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
2531 _holder = holder;
2532 _offset = offset;
2533 _next = next;
2534 debug_only(_is_static_field_id = false;)
2535 }
2536
2537
2538 JNIid* JNIid::find(int offset) {
2539 JNIid* current = this;
2540 while (current != NULL) {
2541 if (current->offset() == offset) return current;
2542 current = current->next();
2543 }
2544 return NULL;
2545 }
2546
2547 void JNIid::oops_do(OopClosure* f) {
2548 for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
2549 f->do_oop(cur->holder_addr());
2550 }
2551 }
2552
2553 void JNIid::deallocate(JNIid* current) {
2554 while (current != NULL) {
2555 JNIid* next = current->next();
2556 delete current;
2557 current = next;
2558 }
2559 }
2560
2561
2562 void JNIid::verify(klassOop holder) {
2563 int first_field_offset = instanceKlass::cast(holder)->offset_of_static_fields();
2564 int end_field_offset;
2565 end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
2566
2567 JNIid* current = this;
2568 while (current != NULL) {
2569 guarantee(current->holder() == holder, "Invalid klass in JNIid");
2570 #ifdef ASSERT
2571 int o = current->offset();
2572 if (current->is_static_field_id()) {
2573 guarantee(o >= first_field_offset && o < end_field_offset, "Invalid static field offset in JNIid");
2574 }
2575 #endif
2576 current = current->next();
2577 }
2578 }
2579
2580
2581 #ifdef ASSERT
2582 void instanceKlass::set_init_state(ClassState state) {
2583 bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
2584 : (_init_state < state);
2585 assert(good_state || state == allocated, "illegal state transition");
2586 _init_state = state;
2587 }
2588 #endif
2589
2590
2591 // RedefineClasses() support for previous versions:
2592
2593 // Add an information node that contains weak references to the
2594 // interesting parts of the previous version of the_class.
2595 // This is also where we clean out any unused weak references.
2596 // Note that while we delete nodes from the _previous_versions
2597 // array, we never delete the array itself until the klass is
2598 // unloaded. The has_been_redefined() query depends on that fact.
2599 //
2600 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
2601 BitMap* emcp_methods, int emcp_method_count) {
2602 assert(Thread::current()->is_VM_thread(),
2603 "only VMThread can add previous versions");
2604
2605 if (_previous_versions == NULL) {
2606 // This is the first previous version so make some space.
2607 // Start with 2 elements under the assumption that the class
2608 // won't be redefined much.
2609 _previous_versions = new (ResourceObj::C_HEAP)
2610 GrowableArray<PreviousVersionNode *>(2, true);
2611 }
2612
2613 // RC_TRACE macro has an embedded ResourceMark
2614 RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
2615 ikh->external_name(), _previous_versions->length(), emcp_method_count));
2616 constantPoolHandle cp_h(ikh->constants());
2617 jobject cp_ref;
2618 if (cp_h->is_shared()) {
2619 // a shared ConstantPool requires a regular reference; a weak
2620 // reference would be collectible
2621 cp_ref = JNIHandles::make_global(cp_h);
2622 } else {
2623 cp_ref = JNIHandles::make_weak_global(cp_h);
2624 }
2625 PreviousVersionNode * pv_node = NULL;
2626 objArrayOop old_methods = ikh->methods();
2627
2628 if (emcp_method_count == 0) {
2629 // non-shared ConstantPool gets a weak reference
2630 pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
2631 RC_TRACE(0x00000400,
2632 ("add: all methods are obsolete; flushing any EMCP weak refs"));
2633 } else {
2634 int local_count = 0;
2635 GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)
2636 GrowableArray<jweak>(emcp_method_count, true);
2637 for (int i = 0; i < old_methods->length(); i++) {
2638 if (emcp_methods->at(i)) {
2639 // this old method is EMCP so save a weak ref
2640 methodOop old_method = (methodOop) old_methods->obj_at(i);
2641 methodHandle old_method_h(old_method);
2642 jweak method_ref = JNIHandles::make_weak_global(old_method_h);
2643 method_refs->append(method_ref);
2644 if (++local_count >= emcp_method_count) {
2645 // no more EMCP methods so bail out now
2646 break;
2647 }
2648 }
2649 }
2650 // non-shared ConstantPool gets a weak reference
2651 pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
2652 }
2653
2654 _previous_versions->append(pv_node);
2655
2656 // Using weak references allows the interesting parts of previous
2657 // classes to be GC'ed when they are no longer needed. Since the
2658 // caller is the VMThread and we are at a safepoint, this is a good
2659 // time to clear out unused weak references.
2660
2661 RC_TRACE(0x00000400, ("add: previous version length=%d",
2662 _previous_versions->length()));
2663
2664 // skip the last entry since we just added it
2665 for (int i = _previous_versions->length() - 2; i >= 0; i--) {
2666 // check the previous versions array for a GC'ed weak refs
2667 pv_node = _previous_versions->at(i);
2668 cp_ref = pv_node->prev_constant_pool();
2669 assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2670 if (cp_ref == NULL) {
2671 delete pv_node;
2672 _previous_versions->remove_at(i);
2673 // Since we are traversing the array backwards, we don't have to
2674 // do anything special with the index.
2675 continue; // robustness
2676 }
2677
2678 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2679 if (cp == NULL) {
2680 // this entry has been GC'ed so remove it
2681 delete pv_node;
2682 _previous_versions->remove_at(i);
2683 // Since we are traversing the array backwards, we don't have to
2684 // do anything special with the index.
2685 continue;
2686 } else {
2687 RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
2688 }
2689
2690 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2691 if (method_refs != NULL) {
2692 RC_TRACE(0x00000400, ("add: previous methods length=%d",
2693 method_refs->length()));
2694 for (int j = method_refs->length() - 1; j >= 0; j--) {
2695 jweak method_ref = method_refs->at(j);
2696 assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2697 if (method_ref == NULL) {
2698 method_refs->remove_at(j);
2699 // Since we are traversing the array backwards, we don't have to
2700 // do anything special with the index.
2701 continue; // robustness
2702 }
2703
2704 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2705 if (method == NULL || emcp_method_count == 0) {
2706 // This method entry has been GC'ed or the current
2707 // RedefineClasses() call has made all methods obsolete
2708 // so remove it.
2709 JNIHandles::destroy_weak_global(method_ref);
2710 method_refs->remove_at(j);
2711 } else {
2712 // RC_TRACE macro has an embedded ResourceMark
2713 RC_TRACE(0x00000400,
2714 ("add: %s(%s): previous method @%d in version @%d is alive",
2715 method->name()->as_C_string(), method->signature()->as_C_string(),
2716 j, i));
2717 }
2718 }
2719 }
2720 }
2721
2722 int obsolete_method_count = old_methods->length() - emcp_method_count;
2723
2724 if (emcp_method_count != 0 && obsolete_method_count != 0 &&
2725 _previous_versions->length() > 1) {
2726 // We have a mix of obsolete and EMCP methods. If there is more
2727 // than the previous version that we just added, then we have to
2728 // clear out any matching EMCP method entries the hard way.
2729 int local_count = 0;
2730 for (int i = 0; i < old_methods->length(); i++) {
2731 if (!emcp_methods->at(i)) {
2732 // only obsolete methods are interesting
2733 methodOop old_method = (methodOop) old_methods->obj_at(i);
2734 Symbol* m_name = old_method->name();
2735 Symbol* m_signature = old_method->signature();
2736
2737 // skip the last entry since we just added it
2738 for (int j = _previous_versions->length() - 2; j >= 0; j--) {
2739 // check the previous versions array for a GC'ed weak refs
2740 pv_node = _previous_versions->at(j);
2741 cp_ref = pv_node->prev_constant_pool();
2742 assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2743 if (cp_ref == NULL) {
2744 delete pv_node;
2745 _previous_versions->remove_at(j);
2746 // Since we are traversing the array backwards, we don't have to
2747 // do anything special with the index.
2748 continue; // robustness
2749 }
2750
2751 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2752 if (cp == NULL) {
2753 // this entry has been GC'ed so remove it
2754 delete pv_node;
2755 _previous_versions->remove_at(j);
2756 // Since we are traversing the array backwards, we don't have to
2757 // do anything special with the index.
2758 continue;
2759 }
2760
2761 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2762 if (method_refs == NULL) {
2763 // We have run into a PreviousVersion generation where
2764 // all methods were made obsolete during that generation's
2765 // RedefineClasses() operation. At the time of that
2766 // operation, all EMCP methods were flushed so we don't
2767 // have to go back any further.
2768 //
2769 // A NULL method_refs is different than an empty method_refs.
2770 // We cannot infer any optimizations about older generations
2771 // from an empty method_refs for the current generation.
2772 break;
2773 }
2774
2775 for (int k = method_refs->length() - 1; k >= 0; k--) {
2776 jweak method_ref = method_refs->at(k);
2777 assert(method_ref != NULL,
2778 "weak method ref was unexpectedly cleared");
2779 if (method_ref == NULL) {
2780 method_refs->remove_at(k);
2781 // Since we are traversing the array backwards, we don't
2782 // have to do anything special with the index.
2783 continue; // robustness
2784 }
2785
2786 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2787 if (method == NULL) {
2788 // this method entry has been GC'ed so skip it
2789 JNIHandles::destroy_weak_global(method_ref);
2790 method_refs->remove_at(k);
2791 continue;
2792 }
2793
2794 if (method->name() == m_name &&
2795 method->signature() == m_signature) {
2796 // The current RedefineClasses() call has made all EMCP
2797 // versions of this method obsolete so mark it as obsolete
2798 // and remove the weak ref.
2799 RC_TRACE(0x00000400,
2800 ("add: %s(%s): flush obsolete method @%d in version @%d",
2801 m_name->as_C_string(), m_signature->as_C_string(), k, j));
2802
2803 method->set_is_obsolete();
2804 JNIHandles::destroy_weak_global(method_ref);
2805 method_refs->remove_at(k);
2806 break;
2807 }
2808 }
2809
2810 // The previous loop may not find a matching EMCP method, but
2811 // that doesn't mean that we can optimize and not go any
2812 // further back in the PreviousVersion generations. The EMCP
2813 // method for this generation could have already been GC'ed,
2814 // but there still may be an older EMCP method that has not
2815 // been GC'ed.
2816 }
2817
2818 if (++local_count >= obsolete_method_count) {
2819 // no more obsolete methods so bail out now
2820 break;
2821 }
2822 }
2823 }
2824 }
2825 } // end add_previous_version()
2826
2827
2828 // Determine if instanceKlass has a previous version.
2829 bool instanceKlass::has_previous_version() const {
2830 if (_previous_versions == NULL) {
2831 // no previous versions array so answer is easy
2832 return false;
2833 }
2834
2835 for (int i = _previous_versions->length() - 1; i >= 0; i--) {
2836 // Check the previous versions array for an info node that hasn't
2837 // been GC'ed
2838 PreviousVersionNode * pv_node = _previous_versions->at(i);
2839
2840 jobject cp_ref = pv_node->prev_constant_pool();
2841 assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
2842 if (cp_ref == NULL) {
2843 continue; // robustness
2844 }
2845
2846 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2847 if (cp != NULL) {
2848 // we have at least one previous version
2849 return true;
2850 }
2851
2852 // We don't have to check the method refs. If the constant pool has
2853 // been GC'ed then so have the methods.
2854 }
2855
2856 // all of the underlying nodes' info has been GC'ed
2857 return false;
2858 } // end has_previous_version()
2859
2860 methodOop instanceKlass::method_with_idnum(int idnum) {
2861 methodOop m = NULL;
2862 if (idnum < methods()->length()) {
2863 m = (methodOop) methods()->obj_at(idnum);
2864 }
2865 if (m == NULL || m->method_idnum() != idnum) {
2866 for (int index = 0; index < methods()->length(); ++index) {
2867 m = (methodOop) methods()->obj_at(index);
2868 if (m->method_idnum() == idnum) {
2869 return m;
2870 }
2871 }
2872 }
2873 return m;
2874 }
2875
2876
2877 // Set the annotation at 'idnum' to 'anno'.
2878 // We don't want to create or extend the array if 'anno' is NULL, since that is the
2879 // default value. However, if the array exists and is long enough, we must set NULL values.
2880 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
2881 objArrayOop md = *md_p;
2882 if (md != NULL && md->length() > idnum) {
2883 md->obj_at_put(idnum, anno);
2884 } else if (anno != NULL) {
2885 // create the array
2886 int length = MAX2(idnum+1, (int)_idnum_allocated_count);
2887 md = oopFactory::new_system_objArray(length, Thread::current());
2888 if (*md_p != NULL) {
2889 // copy the existing entries
2890 for (int index = 0; index < (*md_p)->length(); index++) {
2891 md->obj_at_put(index, (*md_p)->obj_at(index));
2892 }
2893 }
2894 set_annotations(md, md_p);
2895 md->obj_at_put(idnum, anno);
2896 } // if no array and idnum isn't included there is nothing to do
2897 }
2898
2899 // Construct a PreviousVersionNode entry for the array hung off
2900 // the instanceKlass.
2901 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
2902 bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
2903
2904 _prev_constant_pool = prev_constant_pool;
2905 _prev_cp_is_weak = prev_cp_is_weak;
2906 _prev_EMCP_methods = prev_EMCP_methods;
2907 }
2908
2909
2910 // Destroy a PreviousVersionNode
2911 PreviousVersionNode::~PreviousVersionNode() {
2912 if (_prev_constant_pool != NULL) {
2913 if (_prev_cp_is_weak) {
2914 JNIHandles::destroy_weak_global(_prev_constant_pool);
2915 } else {
2916 JNIHandles::destroy_global(_prev_constant_pool);
2917 }
2918 }
2919
2920 if (_prev_EMCP_methods != NULL) {
2921 for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
2922 jweak method_ref = _prev_EMCP_methods->at(i);
2923 if (method_ref != NULL) {
2924 JNIHandles::destroy_weak_global(method_ref);
2925 }
2926 }
2927 delete _prev_EMCP_methods;
2928 }
2929 }
2930
2931
2932 // Construct a PreviousVersionInfo entry
2933 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
2934 _prev_constant_pool_handle = constantPoolHandle(); // NULL handle
2935 _prev_EMCP_method_handles = NULL;
2936
2937 jobject cp_ref = pv_node->prev_constant_pool();
2938 assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
2939 if (cp_ref == NULL) {
2940 return; // robustness
2941 }
2942
2943 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2944 if (cp == NULL) {
2945 // Weak reference has been GC'ed. Since the constant pool has been
2946 // GC'ed, the methods have also been GC'ed.
2947 return;
2948 }
2949
2950 // make the constantPoolOop safe to return
2951 _prev_constant_pool_handle = constantPoolHandle(cp);
2952
2953 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2954 if (method_refs == NULL) {
2955 // the instanceKlass did not have any EMCP methods
2956 return;
2957 }
2958
2959 _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
2960
2961 int n_methods = method_refs->length();
2962 for (int i = 0; i < n_methods; i++) {
2963 jweak method_ref = method_refs->at(i);
2964 assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2965 if (method_ref == NULL) {
2966 continue; // robustness
2967 }
2968
2969 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2970 if (method == NULL) {
2971 // this entry has been GC'ed so skip it
2972 continue;
2973 }
2974
2975 // make the methodOop safe to return
2976 _prev_EMCP_method_handles->append(methodHandle(method));
2977 }
2978 }
2979
2980
2981 // Destroy a PreviousVersionInfo
2982 PreviousVersionInfo::~PreviousVersionInfo() {
2983 // Since _prev_EMCP_method_handles is not C-heap allocated, we
2984 // don't have to delete it.
2985 }
2986
2987
2988 // Construct a helper for walking the previous versions array
2989 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
2990 _previous_versions = ik->previous_versions();
2991 _current_index = 0;
2992 // _hm needs no initialization
2993 _current_p = NULL;
2994 }
2995
2996
2997 // Destroy a PreviousVersionWalker
2998 PreviousVersionWalker::~PreviousVersionWalker() {
2999 // Delete the current info just in case the caller didn't walk to
3000 // the end of the previous versions list. No harm if _current_p is
3001 // already NULL.
3002 delete _current_p;
3003
3004 // When _hm is destroyed, all the Handles returned in
3005 // PreviousVersionInfo objects will be destroyed.
3006 // Also, after this destructor is finished it will be
3007 // safe to delete the GrowableArray allocated in the
3008 // PreviousVersionInfo objects.
3009 }
3010
3011
3012 // Return the interesting information for the next previous version
3013 // of the klass. Returns NULL if there are no more previous versions.
3014 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
3015 if (_previous_versions == NULL) {
3016 // no previous versions so nothing to return
3017 return NULL;
3018 }
3019
3020 delete _current_p; // cleanup the previous info for the caller
3021 _current_p = NULL; // reset to NULL so we don't delete same object twice
3022
3023 int length = _previous_versions->length();
3024
3025 while (_current_index < length) {
3026 PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
3027 PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP)
3028 PreviousVersionInfo(pv_node);
3029
3030 constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
3031 if (cp_h.is_null()) {
3032 delete pv_info;
3033
3034 // The underlying node's info has been GC'ed so try the next one.
3035 // We don't have to check the methods. If the constant pool has
3036 // GC'ed then so have the methods.
3037 continue;
3038 }
3039
3040 // Found a node with non GC'ed info so return it. The caller will
3041 // need to delete pv_info when they are done with it.
3042 _current_p = pv_info;
3043 return pv_info;
3044 }
3045
3046 // all of the underlying nodes' info has been GC'ed
3047 return NULL;
3048 } // end next_previous_version()