1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
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/fieldStreams.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/instanceMirrorKlass.hpp"
42 #include "oops/instanceOop.hpp"
43 #include "oops/methodOop.hpp"
44 #include "oops/objArrayKlassKlass.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/symbol.hpp"
47 #include "prims/jvmtiExport.hpp"
48 #include "prims/jvmtiRedefineClassesTrace.hpp"
49 #include "runtime/fieldDescriptor.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "services/threadService.hpp"
54 #include "utilities/dtrace.hpp"
55 #ifdef TARGET_OS_FAMILY_linux
56 # include "thread_linux.inline.hpp"
57 #endif
58 #ifdef TARGET_OS_FAMILY_solaris
59 # include "thread_solaris.inline.hpp"
60 #endif
61 #ifdef TARGET_OS_FAMILY_windows
62 # include "thread_windows.inline.hpp"
63 #endif
64 #ifdef TARGET_OS_FAMILY_bsd
65 # include "thread_bsd.inline.hpp"
66 #endif
67 #ifndef SERIALGC
68 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
69 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
70 #include "gc_implementation/g1/g1RemSet.inline.hpp"
71 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
72 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
73 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
74 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
75 #include "oops/oop.pcgc.inline.hpp"
76 #endif
77 #ifdef COMPILER1
78 #include "c1/c1_Compiler.hpp"
79 #endif
80
81 #ifdef DTRACE_ENABLED
82
83 #ifndef USDT2
84
85 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
86 char*, intptr_t, oop, intptr_t);
87 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
88 char*, intptr_t, oop, intptr_t, int);
89 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
90 char*, intptr_t, oop, intptr_t, int);
91 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
92 char*, intptr_t, oop, intptr_t, int);
93 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
94 char*, intptr_t, oop, intptr_t, int);
95 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
96 char*, intptr_t, oop, intptr_t, int);
97 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
98 char*, intptr_t, oop, intptr_t, int);
99 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
100 char*, intptr_t, oop, intptr_t, int);
101
102 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) \
103 { \
104 char* data = NULL; \
105 int len = 0; \
106 Symbol* name = (clss)->name(); \
107 if (name != NULL) { \
108 data = (char*)name->bytes(); \
109 len = name->utf8_length(); \
110 } \
111 HS_DTRACE_PROBE4(hotspot, class__initialization__##type, \
112 data, len, (clss)->class_loader(), thread_type); \
113 }
114
115 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
116 { \
117 char* data = NULL; \
118 int len = 0; \
119 Symbol* name = (clss)->name(); \
120 if (name != NULL) { \
121 data = (char*)name->bytes(); \
122 len = name->utf8_length(); \
123 } \
124 HS_DTRACE_PROBE5(hotspot, class__initialization__##type, \
125 data, len, (clss)->class_loader(), thread_type, wait); \
126 }
127 #else /* USDT2 */
128
129 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
130 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
131 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
132 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
133 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
134 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
135 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
136 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
137 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) \
138 { \
139 char* data = NULL; \
140 int len = 0; \
141 Symbol* name = (clss)->name(); \
142 if (name != NULL) { \
143 data = (char*)name->bytes(); \
144 len = name->utf8_length(); \
145 } \
146 HOTSPOT_CLASS_INITIALIZATION_##type( \
147 data, len, (clss)->class_loader(), thread_type); \
148 }
149
150 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
151 { \
152 char* data = NULL; \
153 int len = 0; \
154 Symbol* name = (clss)->name(); \
155 if (name != NULL) { \
156 data = (char*)name->bytes(); \
157 len = name->utf8_length(); \
158 } \
159 HOTSPOT_CLASS_INITIALIZATION_##type( \
160 data, len, (clss)->class_loader(), thread_type, wait); \
161 }
162 #endif /* USDT2 */
163
164 #else // ndef DTRACE_ENABLED
165
166 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
167 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
168
169 #endif // ndef DTRACE_ENABLED
170
171 volatile int instanceKlass::_total_instanceKlass_count = 0;
172
173 bool instanceKlass::should_be_initialized() const {
174 return !is_initialized();
175 }
176
177 klassVtable* instanceKlass::vtable() const {
178 return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());
179 }
180
181 klassItable* instanceKlass::itable() const {
182 return new klassItable(as_klassOop());
183 }
184
185 void instanceKlass::eager_initialize(Thread *thread) {
186 if (!EagerInitialization) return;
187
188 if (this->is_not_initialized()) {
189 // abort if the the class has a class initializer
190 if (this->class_initializer() != NULL) return;
191
192 // abort if it is java.lang.Object (initialization is handled in genesis)
193 klassOop super = this->super();
194 if (super == NULL) return;
195
196 // abort if the super class should be initialized
197 if (!instanceKlass::cast(super)->is_initialized()) return;
198
199 // call body to expose the this pointer
200 instanceKlassHandle this_oop(thread, this->as_klassOop());
201 eager_initialize_impl(this_oop);
202 }
203 }
204
205
206 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
207 EXCEPTION_MARK;
208 ObjectLocker ol(this_oop, THREAD);
209
210 // abort if someone beat us to the initialization
211 if (!this_oop->is_not_initialized()) return; // note: not equivalent to is_initialized()
212
213 ClassState old_state = this_oop->init_state();
214 link_class_impl(this_oop, true, THREAD);
215 if (HAS_PENDING_EXCEPTION) {
216 CLEAR_PENDING_EXCEPTION;
217 // Abort if linking the class throws an exception.
218
219 // Use a test to avoid redundantly resetting the state if there's
220 // no change. Set_init_state() asserts that state changes make
221 // progress, whereas here we might just be spinning in place.
222 if( old_state != this_oop->_init_state )
223 this_oop->set_init_state (old_state);
224 } else {
225 // linking successfull, mark class as initialized
226 this_oop->set_init_state (fully_initialized);
227 // trace
228 if (TraceClassInitialization) {
229 ResourceMark rm(THREAD);
230 tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
231 }
232 }
233 }
234
235
236 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
237 // process. The step comments refers to the procedure described in that section.
238 // Note: implementation moved to static method to expose the this pointer.
239 void instanceKlass::initialize(TRAPS) {
240 if (this->should_be_initialized()) {
241 HandleMark hm(THREAD);
242 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
243 initialize_impl(this_oop, CHECK);
244 // Note: at this point the class may be initialized
245 // OR it may be in the state of being initialized
246 // in case of recursive initialization!
247 } else {
248 assert(is_initialized(), "sanity check");
249 }
250 }
251
252
253 bool instanceKlass::verify_code(
254 instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
255 // 1) Verify the bytecodes
256 Verifier::Mode mode =
257 throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
258 return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
259 }
260
261
262 // Used exclusively by the shared spaces dump mechanism to prevent
263 // classes mapped into the shared regions in new VMs from appearing linked.
264
265 void instanceKlass::unlink_class() {
266 assert(is_linked(), "must be linked");
267 _init_state = loaded;
268 }
269
270 void instanceKlass::link_class(TRAPS) {
271 assert(is_loaded(), "must be loaded");
272 if (!is_linked()) {
273 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
274 link_class_impl(this_oop, true, CHECK);
275 }
276 }
277
278 // Called to verify that a class can link during initialization, without
279 // throwing a VerifyError.
280 bool instanceKlass::link_class_or_fail(TRAPS) {
281 assert(is_loaded(), "must be loaded");
282 if (!is_linked()) {
283 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
284 link_class_impl(this_oop, false, CHECK_false);
285 }
286 return is_linked();
287 }
288
289 bool instanceKlass::link_class_impl(
290 instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
291 // check for error state
292 if (this_oop->is_in_error_state()) {
293 ResourceMark rm(THREAD);
294 THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
295 this_oop->external_name(), false);
296 }
297 // return if already verified
298 if (this_oop->is_linked()) {
299 return true;
300 }
301
302 // Timing
303 // timer handles recursion
304 assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
305 JavaThread* jt = (JavaThread*)THREAD;
306
307 // link super class before linking this class
308 instanceKlassHandle super(THREAD, this_oop->super());
309 if (super.not_null()) {
310 if (super->is_interface()) { // check if super class is an interface
311 ResourceMark rm(THREAD);
312 Exceptions::fthrow(
313 THREAD_AND_LOCATION,
314 vmSymbols::java_lang_IncompatibleClassChangeError(),
315 "class %s has interface %s as super class",
316 this_oop->external_name(),
317 super->external_name()
318 );
319 return false;
320 }
321
322 link_class_impl(super, throw_verifyerror, CHECK_false);
323 }
324
325 // link all interfaces implemented by this class before linking this class
326 objArrayHandle interfaces (THREAD, this_oop->local_interfaces());
327 int num_interfaces = interfaces->length();
328 for (int index = 0; index < num_interfaces; index++) {
329 HandleMark hm(THREAD);
330 instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));
331 link_class_impl(ih, throw_verifyerror, CHECK_false);
332 }
333
334 // in case the class is linked in the process of linking its superclasses
335 if (this_oop->is_linked()) {
336 return true;
337 }
338
339 // trace only the link time for this klass that includes
340 // the verification time
341 PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
342 ClassLoader::perf_class_link_selftime(),
343 ClassLoader::perf_classes_linked(),
344 jt->get_thread_stat()->perf_recursion_counts_addr(),
345 jt->get_thread_stat()->perf_timers_addr(),
346 PerfClassTraceTime::CLASS_LINK);
347
348 // verification & rewriting
349 {
350 ObjectLocker ol(this_oop, THREAD);
351 // rewritten will have been set if loader constraint error found
352 // on an earlier link attempt
353 // don't verify or rewrite if already rewritten
354 if (!this_oop->is_linked()) {
355 if (!this_oop->is_rewritten()) {
356 {
357 // Timer includes any side effects of class verification (resolution,
358 // etc), but not recursive entry into verify_code().
359 PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
360 ClassLoader::perf_class_verify_selftime(),
361 ClassLoader::perf_classes_verified(),
362 jt->get_thread_stat()->perf_recursion_counts_addr(),
363 jt->get_thread_stat()->perf_timers_addr(),
364 PerfClassTraceTime::CLASS_VERIFY);
365 bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
366 if (!verify_ok) {
367 return false;
368 }
369 }
370
371 // Just in case a side-effect of verify linked this class already
372 // (which can sometimes happen since the verifier loads classes
373 // using custom class loaders, which are free to initialize things)
374 if (this_oop->is_linked()) {
375 return true;
376 }
377
378 // also sets rewritten
379 this_oop->rewrite_class(CHECK_false);
380 }
381
382 // relocate jsrs and link methods after they are all rewritten
383 this_oop->relocate_and_link_methods(CHECK_false);
384
385 // Initialize the vtable and interface table after
386 // methods have been rewritten since rewrite may
387 // fabricate new methodOops.
388 // also does loader constraint checking
389 if (!this_oop()->is_shared()) {
390 ResourceMark rm(THREAD);
391 this_oop->vtable()->initialize_vtable(true, CHECK_false);
392 this_oop->itable()->initialize_itable(true, CHECK_false);
393 }
394 #ifdef ASSERT
395 else {
396 ResourceMark rm(THREAD);
397 this_oop->vtable()->verify(tty, true);
398 // In case itable verification is ever added.
399 // this_oop->itable()->verify(tty, true);
400 }
401 #endif
402 this_oop->set_init_state(linked);
403 if (JvmtiExport::should_post_class_prepare()) {
404 Thread *thread = THREAD;
405 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
406 JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
407 }
408 }
409 }
410 return true;
411 }
412
413
414 // Rewrite the byte codes of all of the methods of a class.
415 // The rewriter must be called exactly once. Rewriting must happen after
416 // verification but before the first method of the class is executed.
417 void instanceKlass::rewrite_class(TRAPS) {
418 assert(is_loaded(), "must be loaded");
419 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
420 if (this_oop->is_rewritten()) {
421 assert(this_oop()->is_shared(), "rewriting an unshared class?");
422 return;
423 }
424 Rewriter::rewrite(this_oop, CHECK);
425 this_oop->set_rewritten();
426 }
427
428 // Now relocate and link method entry points after class is rewritten.
429 // This is outside is_rewritten flag. In case of an exception, it can be
430 // executed more than once.
431 void instanceKlass::relocate_and_link_methods(TRAPS) {
432 assert(is_loaded(), "must be loaded");
433 instanceKlassHandle this_oop(THREAD, this->as_klassOop());
434 Rewriter::relocate_and_link(this_oop, CHECK);
435 }
436
437
438 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
439 // Make sure klass is linked (verified) before initialization
440 // A class could already be verified, since it has been reflected upon.
441 this_oop->link_class(CHECK);
442
443 DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);
444
445 bool wait = false;
446
447 // refer to the JVM book page 47 for description of steps
448 // Step 1
449 { ObjectLocker ol(this_oop, THREAD);
450
451 Thread *self = THREAD; // it's passed the current thread
452
453 // Step 2
454 // If we were to use wait() instead of waitInterruptibly() then
455 // we might end up throwing IE from link/symbol resolution sites
456 // that aren't expected to throw. This would wreak havoc. See 6320309.
457 while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
458 wait = true;
459 ol.waitUninterruptibly(CHECK);
460 }
461
462 // Step 3
463 if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
464 DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);
465 return;
466 }
467
468 // Step 4
469 if (this_oop->is_initialized()) {
470 DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);
471 return;
472 }
473
474 // Step 5
475 if (this_oop->is_in_error_state()) {
476 DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);
477 ResourceMark rm(THREAD);
478 const char* desc = "Could not initialize class ";
479 const char* className = this_oop->external_name();
480 size_t msglen = strlen(desc) + strlen(className) + 1;
481 char* message = NEW_RESOURCE_ARRAY(char, msglen);
482 if (NULL == message) {
483 // Out of memory: can't create detailed error message
484 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
485 } else {
486 jio_snprintf(message, msglen, "%s%s", desc, className);
487 THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
488 }
489 }
490
491 // Step 6
492 this_oop->set_init_state(being_initialized);
493 this_oop->set_init_thread(self);
494 }
495
496 // Step 7
497 klassOop super_klass = this_oop->super();
498 if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {
499 Klass::cast(super_klass)->initialize(THREAD);
500
501 if (HAS_PENDING_EXCEPTION) {
502 Handle e(THREAD, PENDING_EXCEPTION);
503 CLEAR_PENDING_EXCEPTION;
504 {
505 EXCEPTION_MARK;
506 this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
507 CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, superclass initialization error is thrown below
508 }
509 DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);
510 THROW_OOP(e());
511 }
512 }
513
514 // Step 8
515 {
516 assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
517 JavaThread* jt = (JavaThread*)THREAD;
518 DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);
519 // Timer includes any side effects of class initialization (resolution,
520 // etc), but not recursive entry into call_class_initializer().
521 PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
522 ClassLoader::perf_class_init_selftime(),
523 ClassLoader::perf_classes_inited(),
524 jt->get_thread_stat()->perf_recursion_counts_addr(),
525 jt->get_thread_stat()->perf_timers_addr(),
526 PerfClassTraceTime::CLASS_CLINIT);
527 this_oop->call_class_initializer(THREAD);
528 }
529
530 // Step 9
531 if (!HAS_PENDING_EXCEPTION) {
532 this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
533 { ResourceMark rm(THREAD);
534 debug_only(this_oop->vtable()->verify(tty, true);)
535 }
536 }
537 else {
538 // Step 10 and 11
539 Handle e(THREAD, PENDING_EXCEPTION);
540 CLEAR_PENDING_EXCEPTION;
541 {
542 EXCEPTION_MARK;
543 this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
544 CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, class initialization error is thrown below
545 }
546 DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);
547 if (e->is_a(SystemDictionary::Error_klass())) {
548 THROW_OOP(e());
549 } else {
550 JavaCallArguments args(e);
551 THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
552 vmSymbols::throwable_void_signature(),
553 &args);
554 }
555 }
556 DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);
557 }
558
559
560 // Note: implementation moved to static method to expose the this pointer.
561 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
562 instanceKlassHandle kh(THREAD, this->as_klassOop());
563 set_initialization_state_and_notify_impl(kh, state, CHECK);
564 }
565
566 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
567 ObjectLocker ol(this_oop, THREAD);
568 this_oop->set_init_state(state);
569 ol.notify_all(CHECK);
570 }
571
572 // The embedded _implementor field can only record one implementor.
573 // When there are more than one implementors, the _implementor field
574 // is set to the interface klassOop itself. Following are the possible
575 // values for the _implementor field:
576 // NULL - no implementor
577 // implementor klassOop - one implementor
578 // self - more than one implementor
579 //
580 // The _implementor field only exists for interfaces.
581 void instanceKlass::add_implementor(klassOop k) {
582 assert(Compile_lock->owned_by_self(), "");
583 assert(is_interface(), "not interface");
584 // Filter out my subinterfaces.
585 // (Note: Interfaces are never on the subklass list.)
586 if (instanceKlass::cast(k)->is_interface()) return;
587
588 // Filter out subclasses whose supers already implement me.
589 // (Note: CHA must walk subclasses of direct implementors
590 // in order to locate indirect implementors.)
591 klassOop sk = instanceKlass::cast(k)->super();
592 if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))
593 // We only need to check one immediate superclass, since the
594 // implements_interface query looks at transitive_interfaces.
595 // Any supers of the super have the same (or fewer) transitive_interfaces.
596 return;
597
598 klassOop ik = implementor();
599 if (ik == NULL) {
600 set_implementor(k);
601 } else if (ik != this->as_klassOop()) {
602 // There is already an implementor. Use itself as an indicator of
603 // more than one implementors.
604 set_implementor(this->as_klassOop());
605 }
606
607 // The implementor also implements the transitive_interfaces
608 for (int index = 0; index < local_interfaces()->length(); index++) {
609 instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);
610 }
611 }
612
613 void instanceKlass::init_implementor() {
614 if (is_interface()) {
615 set_implementor(NULL);
616 }
617 }
618
619
620 void instanceKlass::process_interfaces(Thread *thread) {
621 // link this class into the implementors list of every interface it implements
622 KlassHandle this_as_oop (thread, this->as_klassOop());
623 for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
624 assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");
625 instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));
626 assert(interf->is_interface(), "expected interface");
627 interf->add_implementor(this_as_oop());
628 }
629 }
630
631 bool instanceKlass::can_be_primary_super_slow() const {
632 if (is_interface())
633 return false;
634 else
635 return Klass::can_be_primary_super_slow();
636 }
637
638 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
639 // The secondaries are the implemented interfaces.
640 instanceKlass* ik = instanceKlass::cast(as_klassOop());
641 objArrayHandle interfaces (THREAD, ik->transitive_interfaces());
642 int num_secondaries = num_extra_slots + interfaces->length();
643 if (num_secondaries == 0) {
644 return Universe::the_empty_system_obj_array();
645 } else if (num_extra_slots == 0) {
646 return interfaces();
647 } else {
648 // a mix of both
649 objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);
650 for (int i = 0; i < interfaces->length(); i++) {
651 secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));
652 }
653 return secondaries;
654 }
655 }
656
657 bool instanceKlass::compute_is_subtype_of(klassOop k) {
658 if (Klass::cast(k)->is_interface()) {
659 return implements_interface(k);
660 } else {
661 return Klass::compute_is_subtype_of(k);
662 }
663 }
664
665 bool instanceKlass::implements_interface(klassOop k) const {
666 if (as_klassOop() == k) return true;
667 assert(Klass::cast(k)->is_interface(), "should be an interface class");
668 for (int i = 0; i < transitive_interfaces()->length(); i++) {
669 if (transitive_interfaces()->obj_at(i) == k) {
670 return true;
671 }
672 }
673 return false;
674 }
675
676 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {
677 if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
678 if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
679 report_java_out_of_memory("Requested array size exceeds VM limit");
680 JvmtiExport::post_array_size_exhausted();
681 THROW_OOP_0(Universe::out_of_memory_error_array_size());
682 }
683 int size = objArrayOopDesc::object_size(length);
684 klassOop ak = array_klass(n, CHECK_NULL);
685 KlassHandle h_ak (THREAD, ak);
686 objArrayOop o =
687 (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
688 return o;
689 }
690
691 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {
692 if (TraceFinalizerRegistration) {
693 tty->print("Registered ");
694 i->print_value_on(tty);
695 tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
696 }
697 instanceHandle h_i(THREAD, i);
698 // Pass the handle as argument, JavaCalls::call expects oop as jobjects
699 JavaValue result(T_VOID);
700 JavaCallArguments args(h_i);
701 methodHandle mh (THREAD, Universe::finalizer_register_method());
702 JavaCalls::call(&result, mh, &args, CHECK_NULL);
703 return h_i();
704 }
705
706 instanceOop instanceKlass::allocate_instance(TRAPS) {
707 assert(!oop_is_instanceMirror(), "wrong allocation path");
708 bool has_finalizer_flag = has_finalizer(); // Query before possible GC
709 int size = size_helper(); // Query before forming handle.
710
711 KlassHandle h_k(THREAD, as_klassOop());
712
713 instanceOop i;
714
715 i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
716 if (has_finalizer_flag && !RegisterFinalizersAtInit) {
717 i = register_finalizer(i, CHECK_NULL);
718 }
719 return i;
720 }
721
722 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {
723 // Finalizer registration occurs in the Object.<init> constructor
724 // and constructors normally aren't run when allocating perm
725 // instances so simply disallow finalizable perm objects. This can
726 // be relaxed if a need for it is found.
727 assert(!has_finalizer(), "perm objects not allowed to have finalizers");
728 assert(!oop_is_instanceMirror(), "wrong allocation path");
729 int size = size_helper(); // Query before forming handle.
730 KlassHandle h_k(THREAD, as_klassOop());
731 instanceOop i = (instanceOop)
732 CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
733 return i;
734 }
735
736 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
737 if (is_interface() || is_abstract()) {
738 ResourceMark rm(THREAD);
739 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
740 : vmSymbols::java_lang_InstantiationException(), external_name());
741 }
742 if (as_klassOop() == SystemDictionary::Class_klass()) {
743 ResourceMark rm(THREAD);
744 THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
745 : vmSymbols::java_lang_IllegalAccessException(), external_name());
746 }
747 }
748
749 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
750 instanceKlassHandle this_oop(THREAD, as_klassOop());
751 return array_klass_impl(this_oop, or_null, n, THREAD);
752 }
753
754 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
755 if (this_oop->array_klasses() == NULL) {
756 if (or_null) return NULL;
757
758 ResourceMark rm;
759 JavaThread *jt = (JavaThread *)THREAD;
760 {
761 // Atomic creation of array_klasses
762 MutexLocker mc(Compile_lock, THREAD); // for vtables
763 MutexLocker ma(MultiArray_lock, THREAD);
764
765 // Check if update has already taken place
766 if (this_oop->array_klasses() == NULL) {
767 objArrayKlassKlass* oakk =
768 (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();
769
770 klassOop k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);
771 this_oop->set_array_klasses(k);
772 }
773 }
774 }
775 // _this will always be set at this point
776 objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();
777 if (or_null) {
778 return oak->array_klass_or_null(n);
779 }
780 return oak->array_klass(n, CHECK_NULL);
781 }
782
783 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {
784 return array_klass_impl(or_null, 1, THREAD);
785 }
786
787 void instanceKlass::call_class_initializer(TRAPS) {
788 instanceKlassHandle ik (THREAD, as_klassOop());
789 call_class_initializer_impl(ik, THREAD);
790 }
791
792 static int call_class_initializer_impl_counter = 0; // for debugging
793
794 methodOop instanceKlass::class_initializer() {
795 methodOop clinit = find_method(
796 vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
797 if (clinit != NULL && clinit->has_valid_initializer_flags()) {
798 return clinit;
799 }
800 return NULL;
801 }
802
803 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
804 methodHandle h_method(THREAD, this_oop->class_initializer());
805 assert(!this_oop->is_initialized(), "we cannot initialize twice");
806 if (TraceClassInitialization) {
807 tty->print("%d Initializing ", call_class_initializer_impl_counter++);
808 this_oop->name()->print_value();
809 tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
810 }
811 if (h_method() != NULL) {
812 JavaCallArguments args; // No arguments
813 JavaValue result(T_VOID);
814 JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
815 }
816 }
817
818
819 void instanceKlass::mask_for(methodHandle method, int bci,
820 InterpreterOopMap* entry_for) {
821 // Dirty read, then double-check under a lock.
822 if (_oop_map_cache == NULL) {
823 // Otherwise, allocate a new one.
824 MutexLocker x(OopMapCacheAlloc_lock);
825 // First time use. Allocate a cache in C heap
826 if (_oop_map_cache == NULL) {
827 _oop_map_cache = new OopMapCache();
828 }
829 }
830 // _oop_map_cache is constant after init; lookup below does is own locking.
831 _oop_map_cache->lookup(method, bci, entry_for);
832 }
833
834
835 bool instanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
836 for (JavaFieldStream fs(as_klassOop()); !fs.done(); fs.next()) {
837 Symbol* f_name = fs.name();
838 Symbol* f_sig = fs.signature();
839 if (f_name == name && f_sig == sig) {
840 fd->initialize(as_klassOop(), fs.index());
841 return true;
842 }
843 }
844 return false;
845 }
846
847
848 void instanceKlass::shared_symbols_iterate(SymbolClosure* closure) {
849 Klass::shared_symbols_iterate(closure);
850 closure->do_symbol(&_generic_signature);
851 closure->do_symbol(&_source_file_name);
852
853 for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
854 int name_index = fs.name_index();
855 closure->do_symbol(constants()->symbol_at_addr(name_index));
856 int sig_index = fs.signature_index();
857 closure->do_symbol(constants()->symbol_at_addr(sig_index));
858 }
859 }
860
861
862 klassOop instanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
863 const int n = local_interfaces()->length();
864 for (int i = 0; i < n; i++) {
865 klassOop intf1 = klassOop(local_interfaces()->obj_at(i));
866 assert(Klass::cast(intf1)->is_interface(), "just checking type");
867 // search for field in current interface
868 if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
869 assert(fd->is_static(), "interface field must be static");
870 return intf1;
871 }
872 // search for field in direct superinterfaces
873 klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
874 if (intf2 != NULL) return intf2;
875 }
876 // otherwise field lookup fails
877 return NULL;
878 }
879
880
881 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
882 // search order according to newest JVM spec (5.4.3.2, p.167).
883 // 1) search for field in current klass
884 if (find_local_field(name, sig, fd)) {
885 return as_klassOop();
886 }
887 // 2) search for field recursively in direct superinterfaces
888 { klassOop intf = find_interface_field(name, sig, fd);
889 if (intf != NULL) return intf;
890 }
891 // 3) apply field lookup recursively if superclass exists
892 { klassOop supr = super();
893 if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);
894 }
895 // 4) otherwise field lookup fails
896 return NULL;
897 }
898
899
900 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
901 // search order according to newest JVM spec (5.4.3.2, p.167).
902 // 1) search for field in current klass
903 if (find_local_field(name, sig, fd)) {
904 if (fd->is_static() == is_static) return as_klassOop();
905 }
906 // 2) search for field recursively in direct superinterfaces
907 if (is_static) {
908 klassOop intf = find_interface_field(name, sig, fd);
909 if (intf != NULL) return intf;
910 }
911 // 3) apply field lookup recursively if superclass exists
912 { klassOop supr = super();
913 if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
914 }
915 // 4) otherwise field lookup fails
916 return NULL;
917 }
918
919
920 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
921 for (JavaFieldStream fs(as_klassOop()); !fs.done(); fs.next()) {
922 if (fs.offset() == offset) {
923 fd->initialize(as_klassOop(), fs.index());
924 if (fd->is_static() == is_static) return true;
925 }
926 }
927 return false;
928 }
929
930
931 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
932 klassOop klass = as_klassOop();
933 while (klass != NULL) {
934 if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
935 return true;
936 }
937 klass = Klass::cast(klass)->super();
938 }
939 return false;
940 }
941
942
943 void instanceKlass::methods_do(void f(methodOop method)) {
944 int len = methods()->length();
945 for (int index = 0; index < len; index++) {
946 methodOop m = methodOop(methods()->obj_at(index));
947 assert(m->is_method(), "must be method");
948 f(m);
949 }
950 }
951
952
953 void instanceKlass::do_local_static_fields(FieldClosure* cl) {
954 for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
955 if (fs.access_flags().is_static()) {
956 fieldDescriptor fd;
957 fd.initialize(as_klassOop(), fs.index());
958 cl->do_field(&fd);
959 }
960 }
961 }
962
963
964 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
965 instanceKlassHandle h_this(THREAD, as_klassOop());
966 do_local_static_fields_impl(h_this, f, CHECK);
967 }
968
969
970 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
971 for (JavaFieldStream fs(this_oop()); !fs.done(); fs.next()) {
972 if (fs.access_flags().is_static()) {
973 fieldDescriptor fd;
974 fd.initialize(this_oop(), fs.index());
975 f(&fd, CHECK);
976 }
977 }
978 }
979
980
981 static int compare_fields_by_offset(int* a, int* b) {
982 return a[0] - b[0];
983 }
984
985 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {
986 instanceKlass* super = superklass();
987 if (super != NULL) {
988 super->do_nonstatic_fields(cl);
989 }
990 fieldDescriptor fd;
991 int length = java_fields_count();
992 // In DebugInfo nonstatic fields are sorted by offset.
993 int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass);
994 int j = 0;
995 for (int i = 0; i < length; i += 1) {
996 fd.initialize(as_klassOop(), i);
997 if (!fd.is_static()) {
998 fields_sorted[j + 0] = fd.offset();
999 fields_sorted[j + 1] = i;
1000 j += 2;
1001 }
1002 }
1003 if (j > 0) {
1004 length = j;
1005 // _sort_Fn is defined in growableArray.hpp.
1006 qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
1007 for (int i = 0; i < length; i += 2) {
1008 fd.initialize(as_klassOop(), fields_sorted[i + 1]);
1009 assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
1010 cl->do_field(&fd);
1011 }
1012 }
1013 FREE_C_HEAP_ARRAY(int, fields_sorted, mtClass);
1014 }
1015
1016
1017 void instanceKlass::array_klasses_do(void f(klassOop k)) {
1018 if (array_klasses() != NULL)
1019 arrayKlass::cast(array_klasses())->array_klasses_do(f);
1020 }
1021
1022
1023 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {
1024 f(as_klassOop());
1025 array_klasses_do(f);
1026 }
1027
1028 #ifdef ASSERT
1029 static int linear_search(objArrayOop methods, Symbol* name, Symbol* signature) {
1030 int len = methods->length();
1031 for (int index = 0; index < len; index++) {
1032 methodOop m = (methodOop)(methods->obj_at(index));
1033 assert(m->is_method(), "must be method");
1034 if (m->signature() == signature && m->name() == name) {
1035 return index;
1036 }
1037 }
1038 return -1;
1039 }
1040 #endif
1041
1042 methodOop instanceKlass::find_method(Symbol* name, Symbol* signature) const {
1043 return instanceKlass::find_method(methods(), name, signature);
1044 }
1045
1046 methodOop instanceKlass::find_method(objArrayOop methods, Symbol* name, Symbol* signature) {
1047 int len = methods->length();
1048 // methods are sorted, so do binary search
1049 int l = 0;
1050 int h = len - 1;
1051 while (l <= h) {
1052 int mid = (l + h) >> 1;
1053 methodOop m = (methodOop)methods->obj_at(mid);
1054 assert(m->is_method(), "must be method");
1055 int res = m->name()->fast_compare(name);
1056 if (res == 0) {
1057 // found matching name; do linear search to find matching signature
1058 // first, quick check for common case
1059 if (m->signature() == signature) return m;
1060 // search downwards through overloaded methods
1061 int i;
1062 for (i = mid - 1; i >= l; i--) {
1063 methodOop m = (methodOop)methods->obj_at(i);
1064 assert(m->is_method(), "must be method");
1065 if (m->name() != name) break;
1066 if (m->signature() == signature) return m;
1067 }
1068 // search upwards
1069 for (i = mid + 1; i <= h; i++) {
1070 methodOop m = (methodOop)methods->obj_at(i);
1071 assert(m->is_method(), "must be method");
1072 if (m->name() != name) break;
1073 if (m->signature() == signature) return m;
1074 }
1075 // not found
1076 #ifdef ASSERT
1077 int index = linear_search(methods, name, signature);
1078 assert(index == -1, err_msg("binary search should have found entry %d", index));
1079 #endif
1080 return NULL;
1081 } else if (res < 0) {
1082 l = mid + 1;
1083 } else {
1084 h = mid - 1;
1085 }
1086 }
1087 #ifdef ASSERT
1088 int index = linear_search(methods, name, signature);
1089 assert(index == -1, err_msg("binary search should have found entry %d", index));
1090 #endif
1091 return NULL;
1092 }
1093
1094 methodOop instanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
1095 klassOop klass = as_klassOop();
1096 while (klass != NULL) {
1097 methodOop method = instanceKlass::cast(klass)->find_method(name, signature);
1098 if (method != NULL) return method;
1099 klass = instanceKlass::cast(klass)->super();
1100 }
1101 return NULL;
1102 }
1103
1104 // lookup a method in all the interfaces that this class implements
1105 methodOop instanceKlass::lookup_method_in_all_interfaces(Symbol* name,
1106 Symbol* signature) const {
1107 objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();
1108 int num_ifs = all_ifs->length();
1109 instanceKlass *ik = NULL;
1110 for (int i = 0; i < num_ifs; i++) {
1111 ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));
1112 methodOop m = ik->lookup_method(name, signature);
1113 if (m != NULL) {
1114 return m;
1115 }
1116 }
1117 return NULL;
1118 }
1119
1120 /* jni_id_for_impl for jfieldIds only */
1121 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
1122 MutexLocker ml(JfieldIdCreation_lock);
1123 // Retry lookup after we got the lock
1124 JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
1125 if (probe == NULL) {
1126 // Slow case, allocate new static field identifier
1127 probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());
1128 this_oop->set_jni_ids(probe);
1129 }
1130 return probe;
1131 }
1132
1133
1134 /* jni_id_for for jfieldIds only */
1135 JNIid* instanceKlass::jni_id_for(int offset) {
1136 JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1137 if (probe == NULL) {
1138 probe = jni_id_for_impl(this->as_klassOop(), offset);
1139 }
1140 return probe;
1141 }
1142
1143 u2 instanceKlass::enclosing_method_data(int offset) {
1144 typeArrayOop inner_class_list = inner_classes();
1145 if (inner_class_list == NULL) {
1146 return 0;
1147 }
1148 int length = inner_class_list->length();
1149 if (length % inner_class_next_offset == 0) {
1150 return 0;
1151 } else {
1152 int index = length - enclosing_method_attribute_size;
1153 typeArrayHandle inner_class_list_h(inner_class_list);
1154 assert(offset < enclosing_method_attribute_size, "invalid offset");
1155 return inner_class_list_h->ushort_at(index + offset);
1156 }
1157 }
1158
1159 void instanceKlass::set_enclosing_method_indices(u2 class_index,
1160 u2 method_index) {
1161 typeArrayOop inner_class_list = inner_classes();
1162 assert (inner_class_list != NULL, "_inner_classes list is not set up");
1163 int length = inner_class_list->length();
1164 if (length % inner_class_next_offset == enclosing_method_attribute_size) {
1165 int index = length - enclosing_method_attribute_size;
1166 typeArrayHandle inner_class_list_h(inner_class_list);
1167 inner_class_list_h->ushort_at_put(
1168 index + enclosing_method_class_index_offset, class_index);
1169 inner_class_list_h->ushort_at_put(
1170 index + enclosing_method_method_index_offset, method_index);
1171 }
1172 }
1173
1174 // Lookup or create a jmethodID.
1175 // This code is called by the VMThread and JavaThreads so the
1176 // locking has to be done very carefully to avoid deadlocks
1177 // and/or other cache consistency problems.
1178 //
1179 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
1180 size_t idnum = (size_t)method_h->method_idnum();
1181 jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1182 size_t length = 0;
1183 jmethodID id = NULL;
1184
1185 // We use a double-check locking idiom here because this cache is
1186 // performance sensitive. In the normal system, this cache only
1187 // transitions from NULL to non-NULL which is safe because we use
1188 // release_set_methods_jmethod_ids() to advertise the new cache.
1189 // A partially constructed cache should never be seen by a racing
1190 // thread. We also use release_store_ptr() to save a new jmethodID
1191 // in the cache so a partially constructed jmethodID should never be
1192 // seen either. Cache reads of existing jmethodIDs proceed without a
1193 // lock, but cache writes of a new jmethodID requires uniqueness and
1194 // creation of the cache itself requires no leaks so a lock is
1195 // generally acquired in those two cases.
1196 //
1197 // If the RedefineClasses() API has been used, then this cache can
1198 // grow and we'll have transitions from non-NULL to bigger non-NULL.
1199 // Cache creation requires no leaks and we require safety between all
1200 // cache accesses and freeing of the old cache so a lock is generally
1201 // acquired when the RedefineClasses() API has been used.
1202
1203 if (jmeths != NULL) {
1204 // the cache already exists
1205 if (!ik_h->idnum_can_increment()) {
1206 // the cache can't grow so we can just get the current values
1207 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1208 } else {
1209 // cache can grow so we have to be more careful
1210 if (Threads::number_of_threads() == 0 ||
1211 SafepointSynchronize::is_at_safepoint()) {
1212 // we're single threaded or at a safepoint - no locking needed
1213 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1214 } else {
1215 MutexLocker ml(JmethodIdCreation_lock);
1216 get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1217 }
1218 }
1219 }
1220 // implied else:
1221 // we need to allocate a cache so default length and id values are good
1222
1223 if (jmeths == NULL || // no cache yet
1224 length <= idnum || // cache is too short
1225 id == NULL) { // cache doesn't contain entry
1226
1227 // This function can be called by the VMThread so we have to do all
1228 // things that might block on a safepoint before grabbing the lock.
1229 // Otherwise, we can deadlock with the VMThread or have a cache
1230 // consistency issue. These vars keep track of what we might have
1231 // to free after the lock is dropped.
1232 jmethodID to_dealloc_id = NULL;
1233 jmethodID* to_dealloc_jmeths = NULL;
1234
1235 // may not allocate new_jmeths or use it if we allocate it
1236 jmethodID* new_jmeths = NULL;
1237 if (length <= idnum) {
1238 // allocate a new cache that might be used
1239 size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
1240 new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass);
1241 memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1242 // cache size is stored in element[0], other elements offset by one
1243 new_jmeths[0] = (jmethodID)size;
1244 }
1245
1246 // allocate a new jmethodID that might be used
1247 jmethodID new_id = NULL;
1248 if (method_h->is_old() && !method_h->is_obsolete()) {
1249 // The method passed in is old (but not obsolete), we need to use the current version
1250 methodOop current_method = ik_h->method_with_idnum((int)idnum);
1251 assert(current_method != NULL, "old and but not obsolete, so should exist");
1252 methodHandle current_method_h(current_method == NULL? method_h() : current_method);
1253 new_id = JNIHandles::make_jmethod_id(current_method_h);
1254 } else {
1255 // It is the current version of the method or an obsolete method,
1256 // use the version passed in
1257 new_id = JNIHandles::make_jmethod_id(method_h);
1258 }
1259
1260 if (Threads::number_of_threads() == 0 ||
1261 SafepointSynchronize::is_at_safepoint()) {
1262 // we're single threaded or at a safepoint - no locking needed
1263 id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1264 &to_dealloc_id, &to_dealloc_jmeths);
1265 } else {
1266 MutexLocker ml(JmethodIdCreation_lock);
1267 id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1268 &to_dealloc_id, &to_dealloc_jmeths);
1269 }
1270
1271 // The lock has been dropped so we can free resources.
1272 // Free up either the old cache or the new cache if we allocated one.
1273 if (to_dealloc_jmeths != NULL) {
1274 FreeHeap(to_dealloc_jmeths);
1275 }
1276 // free up the new ID since it wasn't needed
1277 if (to_dealloc_id != NULL) {
1278 JNIHandles::destroy_jmethod_id(to_dealloc_id);
1279 }
1280 }
1281 return id;
1282 }
1283
1284
1285 // Common code to fetch the jmethodID from the cache or update the
1286 // cache with the new jmethodID. This function should never do anything
1287 // that causes the caller to go to a safepoint or we can deadlock with
1288 // the VMThread or have cache consistency issues.
1289 //
1290 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
1291 instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
1292 jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1293 jmethodID** to_dealloc_jmeths_p) {
1294 assert(new_id != NULL, "sanity check");
1295 assert(to_dealloc_id_p != NULL, "sanity check");
1296 assert(to_dealloc_jmeths_p != NULL, "sanity check");
1297 assert(Threads::number_of_threads() == 0 ||
1298 SafepointSynchronize::is_at_safepoint() ||
1299 JmethodIdCreation_lock->owned_by_self(), "sanity check");
1300
1301 // reacquire the cache - we are locked, single threaded or at a safepoint
1302 jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1303 jmethodID id = NULL;
1304 size_t length = 0;
1305
1306 if (jmeths == NULL || // no cache yet
1307 (length = (size_t)jmeths[0]) <= idnum) { // cache is too short
1308 if (jmeths != NULL) {
1309 // copy any existing entries from the old cache
1310 for (size_t index = 0; index < length; index++) {
1311 new_jmeths[index+1] = jmeths[index+1];
1312 }
1313 *to_dealloc_jmeths_p = jmeths; // save old cache for later delete
1314 }
1315 ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
1316 } else {
1317 // fetch jmethodID (if any) from the existing cache
1318 id = jmeths[idnum+1];
1319 *to_dealloc_jmeths_p = new_jmeths; // save new cache for later delete
1320 }
1321 if (id == NULL) {
1322 // No matching jmethodID in the existing cache or we have a new
1323 // cache or we just grew the cache. This cache write is done here
1324 // by the first thread to win the foot race because a jmethodID
1325 // needs to be unique once it is generally available.
1326 id = new_id;
1327
1328 // The jmethodID cache can be read while unlocked so we have to
1329 // make sure the new jmethodID is complete before installing it
1330 // in the cache.
1331 OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1332 } else {
1333 *to_dealloc_id_p = new_id; // save new id for later delete
1334 }
1335 return id;
1336 }
1337
1338
1339 // Common code to get the jmethodID cache length and the jmethodID
1340 // value at index idnum if there is one.
1341 //
1342 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1343 size_t idnum, size_t *length_p, jmethodID* id_p) {
1344 assert(cache != NULL, "sanity check");
1345 assert(length_p != NULL, "sanity check");
1346 assert(id_p != NULL, "sanity check");
1347
1348 // cache size is stored in element[0], other elements offset by one
1349 *length_p = (size_t)cache[0];
1350 if (*length_p <= idnum) { // cache is too short
1351 *id_p = NULL;
1352 } else {
1353 *id_p = cache[idnum+1]; // fetch jmethodID (if any)
1354 }
1355 }
1356
1357
1358 // Lookup a jmethodID, NULL if not found. Do no blocking, no allocations, no handles
1359 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
1360 size_t idnum = (size_t)method->method_idnum();
1361 jmethodID* jmeths = methods_jmethod_ids_acquire();
1362 size_t length; // length assigned as debugging crumb
1363 jmethodID id = NULL;
1364 if (jmeths != NULL && // If there is a cache
1365 (length = (size_t)jmeths[0]) > idnum) { // and if it is long enough,
1366 id = jmeths[idnum+1]; // Look up the id (may be NULL)
1367 }
1368 return id;
1369 }
1370
1371
1372 // Cache an itable index
1373 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
1374 int* indices = methods_cached_itable_indices_acquire();
1375 int* to_dealloc_indices = NULL;
1376
1377 // We use a double-check locking idiom here because this cache is
1378 // performance sensitive. In the normal system, this cache only
1379 // transitions from NULL to non-NULL which is safe because we use
1380 // release_set_methods_cached_itable_indices() to advertise the
1381 // new cache. A partially constructed cache should never be seen
1382 // by a racing thread. Cache reads and writes proceed without a
1383 // lock, but creation of the cache itself requires no leaks so a
1384 // lock is generally acquired in that case.
1385 //
1386 // If the RedefineClasses() API has been used, then this cache can
1387 // grow and we'll have transitions from non-NULL to bigger non-NULL.
1388 // Cache creation requires no leaks and we require safety between all
1389 // cache accesses and freeing of the old cache so a lock is generally
1390 // acquired when the RedefineClasses() API has been used.
1391
1392 if (indices == NULL || idnum_can_increment()) {
1393 // we need a cache or the cache can grow
1394 MutexLocker ml(JNICachedItableIndex_lock);
1395 // reacquire the cache to see if another thread already did the work
1396 indices = methods_cached_itable_indices_acquire();
1397 size_t length = 0;
1398 // cache size is stored in element[0], other elements offset by one
1399 if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
1400 size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1401 int* new_indices = NEW_C_HEAP_ARRAY(int, size+1, mtClass);
1402 new_indices[0] = (int)size;
1403 // copy any existing entries
1404 size_t i;
1405 for (i = 0; i < length; i++) {
1406 new_indices[i+1] = indices[i+1];
1407 }
1408 // Set all the rest to -1
1409 for (i = length; i < size; i++) {
1410 new_indices[i+1] = -1;
1411 }
1412 if (indices != NULL) {
1413 // We have an old cache to delete so save it for after we
1414 // drop the lock.
1415 to_dealloc_indices = indices;
1416 }
1417 release_set_methods_cached_itable_indices(indices = new_indices);
1418 }
1419
1420 if (idnum_can_increment()) {
1421 // this cache can grow so we have to write to it safely
1422 indices[idnum+1] = index;
1423 }
1424 } else {
1425 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
1426 }
1427
1428 if (!idnum_can_increment()) {
1429 // The cache cannot grow and this JNI itable index value does not
1430 // have to be unique like a jmethodID. If there is a race to set it,
1431 // it doesn't matter.
1432 indices[idnum+1] = index;
1433 }
1434
1435 if (to_dealloc_indices != NULL) {
1436 // we allocated a new cache so free the old one
1437 FreeHeap(to_dealloc_indices);
1438 }
1439 }
1440
1441
1442 // Retrieve a cached itable index
1443 int instanceKlass::cached_itable_index(size_t idnum) {
1444 int* indices = methods_cached_itable_indices_acquire();
1445 if (indices != NULL && ((size_t)indices[0]) > idnum) {
1446 // indices exist and are long enough, retrieve possible cached
1447 return indices[idnum+1];
1448 }
1449 return -1;
1450 }
1451
1452
1453 //
1454 // Walk the list of dependent nmethods searching for nmethods which
1455 // are dependent on the changes that were passed in and mark them for
1456 // deoptimization. Returns the number of nmethods found.
1457 //
1458 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
1459 assert_locked_or_safepoint(CodeCache_lock);
1460 int found = 0;
1461 nmethodBucket* b = _dependencies;
1462 while (b != NULL) {
1463 nmethod* nm = b->get_nmethod();
1464 // since dependencies aren't removed until an nmethod becomes a zombie,
1465 // the dependency list may contain nmethods which aren't alive.
1466 if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
1467 if (TraceDependencies) {
1468 ResourceMark rm;
1469 tty->print_cr("Marked for deoptimization");
1470 tty->print_cr(" context = %s", this->external_name());
1471 changes.print();
1472 nm->print();
1473 nm->print_dependencies();
1474 }
1475 nm->mark_for_deoptimization();
1476 found++;
1477 }
1478 b = b->next();
1479 }
1480 return found;
1481 }
1482
1483
1484 //
1485 // Add an nmethodBucket to the list of dependencies for this nmethod.
1486 // It's possible that an nmethod has multiple dependencies on this klass
1487 // so a count is kept for each bucket to guarantee that creation and
1488 // deletion of dependencies is consistent.
1489 //
1490 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
1491 assert_locked_or_safepoint(CodeCache_lock);
1492 nmethodBucket* b = _dependencies;
1493 nmethodBucket* last = NULL;
1494 while (b != NULL) {
1495 if (nm == b->get_nmethod()) {
1496 b->increment();
1497 return;
1498 }
1499 b = b->next();
1500 }
1501 _dependencies = new nmethodBucket(nm, _dependencies);
1502 }
1503
1504
1505 //
1506 // Decrement count of the nmethod in the dependency list and remove
1507 // the bucket competely when the count goes to 0. This method must
1508 // find a corresponding bucket otherwise there's a bug in the
1509 // recording of dependecies.
1510 //
1511 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
1512 assert_locked_or_safepoint(CodeCache_lock);
1513 nmethodBucket* b = _dependencies;
1514 nmethodBucket* last = NULL;
1515 while (b != NULL) {
1516 if (nm == b->get_nmethod()) {
1517 if (b->decrement() == 0) {
1518 if (last == NULL) {
1519 _dependencies = b->next();
1520 } else {
1521 last->set_next(b->next());
1522 }
1523 delete b;
1524 }
1525 return;
1526 }
1527 last = b;
1528 b = b->next();
1529 }
1530 #ifdef ASSERT
1531 tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
1532 nm->print();
1533 #endif // ASSERT
1534 ShouldNotReachHere();
1535 }
1536
1537
1538 #ifndef PRODUCT
1539 void instanceKlass::print_dependent_nmethods(bool verbose) {
1540 nmethodBucket* b = _dependencies;
1541 int idx = 0;
1542 while (b != NULL) {
1543 nmethod* nm = b->get_nmethod();
1544 tty->print("[%d] count=%d { ", idx++, b->count());
1545 if (!verbose) {
1546 nm->print_on(tty, "nmethod");
1547 tty->print_cr(" } ");
1548 } else {
1549 nm->print();
1550 nm->print_dependencies();
1551 tty->print_cr("--- } ");
1552 }
1553 b = b->next();
1554 }
1555 }
1556
1557
1558 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
1559 nmethodBucket* b = _dependencies;
1560 while (b != NULL) {
1561 if (nm == b->get_nmethod()) {
1562 return true;
1563 }
1564 b = b->next();
1565 }
1566 return false;
1567 }
1568 #endif //PRODUCT
1569
1570
1571 #ifdef ASSERT
1572 template <class T> void assert_is_in(T *p) {
1573 T heap_oop = oopDesc::load_heap_oop(p);
1574 if (!oopDesc::is_null(heap_oop)) {
1575 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1576 assert(Universe::heap()->is_in(o), "should be in heap");
1577 }
1578 }
1579 template <class T> void assert_is_in_closed_subset(T *p) {
1580 T heap_oop = oopDesc::load_heap_oop(p);
1581 if (!oopDesc::is_null(heap_oop)) {
1582 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1583 assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
1584 }
1585 }
1586 template <class T> void assert_is_in_reserved(T *p) {
1587 T heap_oop = oopDesc::load_heap_oop(p);
1588 if (!oopDesc::is_null(heap_oop)) {
1589 oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1590 assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
1591 }
1592 }
1593 template <class T> void assert_nothing(T *p) {}
1594
1595 #else
1596 template <class T> void assert_is_in(T *p) {}
1597 template <class T> void assert_is_in_closed_subset(T *p) {}
1598 template <class T> void assert_is_in_reserved(T *p) {}
1599 template <class T> void assert_nothing(T *p) {}
1600 #endif // ASSERT
1601
1602 //
1603 // Macros that iterate over areas of oops which are specialized on type of
1604 // oop pointer either narrow or wide, depending on UseCompressedOops
1605 //
1606 // Parameters are:
1607 // T - type of oop to point to (either oop or narrowOop)
1608 // start_p - starting pointer for region to iterate over
1609 // count - number of oops or narrowOops to iterate over
1610 // do_oop - action to perform on each oop (it's arbitrary C code which
1611 // makes it more efficient to put in a macro rather than making
1612 // it a template function)
1613 // assert_fn - assert function which is template function because performance
1614 // doesn't matter when enabled.
1615 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
1616 T, start_p, count, do_oop, \
1617 assert_fn) \
1618 { \
1619 T* p = (T*)(start_p); \
1620 T* const end = p + (count); \
1621 while (p < end) { \
1622 (assert_fn)(p); \
1623 do_oop; \
1624 ++p; \
1625 } \
1626 }
1627
1628 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
1629 T, start_p, count, do_oop, \
1630 assert_fn) \
1631 { \
1632 T* const start = (T*)(start_p); \
1633 T* p = start + (count); \
1634 while (start < p) { \
1635 --p; \
1636 (assert_fn)(p); \
1637 do_oop; \
1638 } \
1639 }
1640
1641 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
1642 T, start_p, count, low, high, \
1643 do_oop, assert_fn) \
1644 { \
1645 T* const l = (T*)(low); \
1646 T* const h = (T*)(high); \
1647 assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
1648 mask_bits((intptr_t)h, sizeof(T)-1) == 0, \
1649 "bounded region must be properly aligned"); \
1650 T* p = (T*)(start_p); \
1651 T* end = p + (count); \
1652 if (p < l) p = l; \
1653 if (end > h) end = h; \
1654 while (p < end) { \
1655 (assert_fn)(p); \
1656 do_oop; \
1657 ++p; \
1658 } \
1659 }
1660
1661
1662 // The following macros call specialized macros, passing either oop or
1663 // narrowOop as the specialization type. These test the UseCompressedOops
1664 // flag.
1665 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn) \
1666 { \
1667 /* Compute oopmap block range. The common case \
1668 is nonstatic_oop_map_size == 1. */ \
1669 OopMapBlock* map = start_of_nonstatic_oop_maps(); \
1670 OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \
1671 if (UseCompressedOops) { \
1672 while (map < end_map) { \
1673 InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
1674 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1675 do_oop, assert_fn) \
1676 ++map; \
1677 } \
1678 } else { \
1679 while (map < end_map) { \
1680 InstanceKlass_SPECIALIZED_OOP_ITERATE(oop, \
1681 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1682 do_oop, assert_fn) \
1683 ++map; \
1684 } \
1685 } \
1686 }
1687
1688 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn) \
1689 { \
1690 OopMapBlock* const start_map = start_of_nonstatic_oop_maps(); \
1691 OopMapBlock* map = start_map + nonstatic_oop_map_count(); \
1692 if (UseCompressedOops) { \
1693 while (start_map < map) { \
1694 --map; \
1695 InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop, \
1696 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1697 do_oop, assert_fn) \
1698 } \
1699 } else { \
1700 while (start_map < map) { \
1701 --map; \
1702 InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop, \
1703 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1704 do_oop, assert_fn) \
1705 } \
1706 } \
1707 }
1708
1709 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop, \
1710 assert_fn) \
1711 { \
1712 /* Compute oopmap block range. The common case is \
1713 nonstatic_oop_map_size == 1, so we accept the \
1714 usually non-existent extra overhead of examining \
1715 all the maps. */ \
1716 OopMapBlock* map = start_of_nonstatic_oop_maps(); \
1717 OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \
1718 if (UseCompressedOops) { \
1719 while (map < end_map) { \
1720 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
1721 obj->obj_field_addr<narrowOop>(map->offset()), map->count(), \
1722 low, high, \
1723 do_oop, assert_fn) \
1724 ++map; \
1725 } \
1726 } else { \
1727 while (map < end_map) { \
1728 InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop, \
1729 obj->obj_field_addr<oop>(map->offset()), map->count(), \
1730 low, high, \
1731 do_oop, assert_fn) \
1732 ++map; \
1733 } \
1734 } \
1735 }
1736
1737 void instanceKlass::oop_follow_contents(oop obj) {
1738 assert(obj != NULL, "can't follow the content of NULL object");
1739 obj->follow_header();
1740 InstanceKlass_OOP_MAP_ITERATE( \
1741 obj, \
1742 MarkSweep::mark_and_push(p), \
1743 assert_is_in_closed_subset)
1744 }
1745
1746 #ifndef SERIALGC
1747 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,
1748 oop obj) {
1749 assert(obj != NULL, "can't follow the content of NULL object");
1750 obj->follow_header(cm);
1751 InstanceKlass_OOP_MAP_ITERATE( \
1752 obj, \
1753 PSParallelCompact::mark_and_push(cm, p), \
1754 assert_is_in)
1755 }
1756 #endif // SERIALGC
1757
1758 // closure's do_header() method dicates whether the given closure should be
1759 // applied to the klass ptr in the object header.
1760
1761 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
1762 \
1763 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
1764 SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1765 /* header */ \
1766 if (closure->do_header()) { \
1767 obj->oop_iterate_header(closure); \
1768 } \
1769 InstanceKlass_OOP_MAP_ITERATE( \
1770 obj, \
1771 SpecializationStats:: \
1772 record_do_oop_call##nv_suffix(SpecializationStats::ik); \
1773 (closure)->do_oop##nv_suffix(p), \
1774 assert_is_in_closed_subset) \
1775 return size_helper(); \
1776 }
1777
1778 #ifndef SERIALGC
1779 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
1780 \
1781 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj, \
1782 OopClosureType* closure) { \
1783 SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
1784 /* header */ \
1785 if (closure->do_header()) { \
1786 obj->oop_iterate_header(closure); \
1787 } \
1788 /* instance variables */ \
1789 InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
1790 obj, \
1791 SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
1792 (closure)->do_oop##nv_suffix(p), \
1793 assert_is_in_closed_subset) \
1794 return size_helper(); \
1795 }
1796 #endif // !SERIALGC
1797
1798 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
1799 \
1800 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj, \
1801 OopClosureType* closure, \
1802 MemRegion mr) { \
1803 SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1804 if (closure->do_header()) { \
1805 obj->oop_iterate_header(closure, mr); \
1806 } \
1807 InstanceKlass_BOUNDED_OOP_MAP_ITERATE( \
1808 obj, mr.start(), mr.end(), \
1809 (closure)->do_oop##nv_suffix(p), \
1810 assert_is_in_closed_subset) \
1811 return size_helper(); \
1812 }
1813
1814 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1815 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1816 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1817 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1818 #ifndef SERIALGC
1819 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1820 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1821 #endif // !SERIALGC
1822
1823 int instanceKlass::oop_adjust_pointers(oop obj) {
1824 int size = size_helper();
1825 InstanceKlass_OOP_MAP_ITERATE( \
1826 obj, \
1827 MarkSweep::adjust_pointer(p), \
1828 assert_is_in)
1829 obj->adjust_header();
1830 return size;
1831 }
1832
1833 #ifndef SERIALGC
1834 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
1835 InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
1836 obj, \
1837 if (PSScavenge::should_scavenge(p)) { \
1838 pm->claim_or_forward_depth(p); \
1839 }, \
1840 assert_nothing )
1841 }
1842
1843 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
1844 InstanceKlass_OOP_MAP_ITERATE( \
1845 obj, \
1846 PSParallelCompact::adjust_pointer(p), \
1847 assert_nothing)
1848 return size_helper();
1849 }
1850
1851 #endif // SERIALGC
1852
1853 // This klass is alive but the implementor link is not followed/updated.
1854 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
1855
1856 void instanceKlass::follow_weak_klass_links(
1857 BoolObjectClosure* is_alive, OopClosure* keep_alive) {
1858 assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
1859
1860 if (is_interface()) {
1861 if (ClassUnloading) {
1862 klassOop impl = implementor();
1863 if (impl != NULL) {
1864 if (!is_alive->do_object_b(impl)) {
1865 // remove this guy
1866 *adr_implementor() = NULL;
1867 }
1868 }
1869 } else {
1870 assert(adr_implementor() != NULL, "just checking");
1871 keep_alive->do_oop(adr_implementor());
1872 }
1873 }
1874
1875 Klass::follow_weak_klass_links(is_alive, keep_alive);
1876 }
1877
1878 void instanceKlass::remove_unshareable_info() {
1879 Klass::remove_unshareable_info();
1880 init_implementor();
1881 }
1882
1883 static void clear_all_breakpoints(methodOop m) {
1884 m->clear_all_breakpoints();
1885 }
1886
1887 void instanceKlass::release_C_heap_structures() {
1888 // Deallocate oop map cache
1889 if (_oop_map_cache != NULL) {
1890 delete _oop_map_cache;
1891 _oop_map_cache = NULL;
1892 }
1893
1894 // Deallocate JNI identifiers for jfieldIDs
1895 JNIid::deallocate(jni_ids());
1896 set_jni_ids(NULL);
1897
1898 jmethodID* jmeths = methods_jmethod_ids_acquire();
1899 if (jmeths != (jmethodID*)NULL) {
1900 release_set_methods_jmethod_ids(NULL);
1901 FreeHeap(jmeths);
1902 }
1903
1904 // Deallocate MemberNameTable
1905 {
1906 Mutex* lock_or_null = SafepointSynchronize::is_at_safepoint() ? NULL : MemberNameTable_lock;
1907 MutexLockerEx ml(lock_or_null, Mutex::_no_safepoint_check_flag);
1908 MemberNameTable* mnt = member_names();
1909 if (mnt != NULL) {
1910 delete mnt;
1911 set_member_names(NULL);
1912 }
1913 }
1914
1915 int* indices = methods_cached_itable_indices_acquire();
1916 if (indices != (int*)NULL) {
1917 release_set_methods_cached_itable_indices(NULL);
1918 FreeHeap(indices);
1919 }
1920
1921 // release dependencies
1922 nmethodBucket* b = _dependencies;
1923 _dependencies = NULL;
1924 while (b != NULL) {
1925 nmethodBucket* next = b->next();
1926 delete b;
1927 b = next;
1928 }
1929
1930 // Deallocate breakpoint records
1931 if (breakpoints() != 0x0) {
1932 methods_do(clear_all_breakpoints);
1933 assert(breakpoints() == 0x0, "should have cleared breakpoints");
1934 }
1935
1936 // deallocate information about previous versions
1937 if (_previous_versions != NULL) {
1938 for (int i = _previous_versions->length() - 1; i >= 0; i--) {
1939 PreviousVersionNode * pv_node = _previous_versions->at(i);
1940 delete pv_node;
1941 }
1942 delete _previous_versions;
1943 _previous_versions = NULL;
1944 }
1945
1946 // deallocate the cached class file
1947 if (_cached_class_file_bytes != NULL) {
1948 os::free(_cached_class_file_bytes, mtClass);
1949 _cached_class_file_bytes = NULL;
1950 _cached_class_file_len = 0;
1951 }
1952
1953 // Decrement symbol reference counts associated with the unloaded class.
1954 if (_name != NULL) _name->decrement_refcount();
1955 // unreference array name derived from this class name (arrays of an unloaded
1956 // class can't be referenced anymore).
1957 if (_array_name != NULL) _array_name->decrement_refcount();
1958 if (_source_file_name != NULL) _source_file_name->decrement_refcount();
1959 // walk constant pool and decrement symbol reference counts
1960 _constants->unreference_symbols();
1961
1962 if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension, mtClass);
1963
1964 assert(_total_instanceKlass_count >= 1, "Sanity check");
1965 Atomic::dec(&_total_instanceKlass_count);
1966 }
1967
1968 void instanceKlass::set_source_file_name(Symbol* n) {
1969 _source_file_name = n;
1970 if (_source_file_name != NULL) _source_file_name->increment_refcount();
1971 }
1972
1973 void instanceKlass::set_source_debug_extension(char* array, int length) {
1974 if (array == NULL) {
1975 _source_debug_extension = NULL;
1976 } else {
1977 // Adding one to the attribute length in order to store a null terminator
1978 // character could cause an overflow because the attribute length is
1979 // already coded with an u4 in the classfile, but in practice, it's
1980 // unlikely to happen.
1981 assert((length+1) > length, "Overflow checking");
1982 char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
1983 for (int i = 0; i < length; i++) {
1984 sde[i] = array[i];
1985 }
1986 sde[length] = '\0';
1987 _source_debug_extension = sde;
1988 }
1989 }
1990
1991 address instanceKlass::static_field_addr(int offset) {
1992 return (address)(offset + instanceMirrorKlass::offset_of_static_fields() + (intptr_t)java_mirror());
1993 }
1994
1995
1996 const char* instanceKlass::signature_name() const {
1997 const char* src = (const char*) (name()->as_C_string());
1998 const int src_length = (int)strlen(src);
1999 char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
2000 int src_index = 0;
2001 int dest_index = 0;
2002 dest[dest_index++] = 'L';
2003 while (src_index < src_length) {
2004 dest[dest_index++] = src[src_index++];
2005 }
2006 dest[dest_index++] = ';';
2007 dest[dest_index] = '\0';
2008 return dest;
2009 }
2010
2011 // different verisons of is_same_class_package
2012 bool instanceKlass::is_same_class_package(klassOop class2) {
2013 klassOop class1 = as_klassOop();
2014 oop classloader1 = instanceKlass::cast(class1)->class_loader();
2015 Symbol* classname1 = Klass::cast(class1)->name();
2016
2017 if (Klass::cast(class2)->oop_is_objArray()) {
2018 class2 = objArrayKlass::cast(class2)->bottom_klass();
2019 }
2020 oop classloader2;
2021 if (Klass::cast(class2)->oop_is_instance()) {
2022 classloader2 = instanceKlass::cast(class2)->class_loader();
2023 } else {
2024 assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
2025 classloader2 = NULL;
2026 }
2027 Symbol* classname2 = Klass::cast(class2)->name();
2028
2029 return instanceKlass::is_same_class_package(classloader1, classname1,
2030 classloader2, classname2);
2031 }
2032
2033 bool instanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
2034 klassOop class1 = as_klassOop();
2035 oop classloader1 = instanceKlass::cast(class1)->class_loader();
2036 Symbol* classname1 = Klass::cast(class1)->name();
2037
2038 return instanceKlass::is_same_class_package(classloader1, classname1,
2039 classloader2, classname2);
2040 }
2041
2042 // return true if two classes are in the same package, classloader
2043 // and classname information is enough to determine a class's package
2044 bool instanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
2045 oop class_loader2, Symbol* class_name2) {
2046 if (class_loader1 != class_loader2) {
2047 return false;
2048 } else if (class_name1 == class_name2) {
2049 return true; // skip painful bytewise comparison
2050 } else {
2051 ResourceMark rm;
2052
2053 // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
2054 // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
2055 // Otherwise, we just compare jbyte values between the strings.
2056 const jbyte *name1 = class_name1->base();
2057 const jbyte *name2 = class_name2->base();
2058
2059 const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
2060 const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
2061
2062 if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
2063 // One of the two doesn't have a package. Only return true
2064 // if the other one also doesn't have a package.
2065 return last_slash1 == last_slash2;
2066 } else {
2067 // Skip over '['s
2068 if (*name1 == '[') {
2069 do {
2070 name1++;
2071 } while (*name1 == '[');
2072 if (*name1 != 'L') {
2073 // Something is terribly wrong. Shouldn't be here.
2074 return false;
2075 }
2076 }
2077 if (*name2 == '[') {
2078 do {
2079 name2++;
2080 } while (*name2 == '[');
2081 if (*name2 != 'L') {
2082 // Something is terribly wrong. Shouldn't be here.
2083 return false;
2084 }
2085 }
2086
2087 // Check that package part is identical
2088 int length1 = last_slash1 - name1;
2089 int length2 = last_slash2 - name2;
2090
2091 return UTF8::equal(name1, length1, name2, length2);
2092 }
2093 }
2094 }
2095
2096 // Returns true iff super_method can be overridden by a method in targetclassname
2097 // See JSL 3rd edition 8.4.6.1
2098 // Assumes name-signature match
2099 // "this" is instanceKlass of super_method which must exist
2100 // note that the instanceKlass of the method in the targetclassname has not always been created yet
2101 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2102 // Private methods can not be overridden
2103 if (super_method->is_private()) {
2104 return false;
2105 }
2106 // If super method is accessible, then override
2107 if ((super_method->is_protected()) ||
2108 (super_method->is_public())) {
2109 return true;
2110 }
2111 // Package-private methods are not inherited outside of package
2112 assert(super_method->is_package_private(), "must be package private");
2113 return(is_same_class_package(targetclassloader(), targetclassname));
2114 }
2115
2116 /* defined for now in jvm.cpp, for historical reasons *--
2117 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
2118 Symbol*& simple_name_result, TRAPS) {
2119 ...
2120 }
2121 */
2122
2123 // tell if two classes have the same enclosing class (at package level)
2124 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
2125 klassOop class2_oop, TRAPS) {
2126 if (class2_oop == class1->as_klassOop()) return true;
2127 if (!Klass::cast(class2_oop)->oop_is_instance()) return false;
2128 instanceKlassHandle class2(THREAD, class2_oop);
2129
2130 // must be in same package before we try anything else
2131 if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
2132 return false;
2133
2134 // As long as there is an outer1.getEnclosingClass,
2135 // shift the search outward.
2136 instanceKlassHandle outer1 = class1;
2137 for (;;) {
2138 // As we walk along, look for equalities between outer1 and class2.
2139 // Eventually, the walks will terminate as outer1 stops
2140 // at the top-level class around the original class.
2141 bool ignore_inner_is_member;
2142 klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
2143 CHECK_false);
2144 if (next == NULL) break;
2145 if (next == class2()) return true;
2146 outer1 = instanceKlassHandle(THREAD, next);
2147 }
2148
2149 // Now do the same for class2.
2150 instanceKlassHandle outer2 = class2;
2151 for (;;) {
2152 bool ignore_inner_is_member;
2153 klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2154 CHECK_false);
2155 if (next == NULL) break;
2156 // Might as well check the new outer against all available values.
2157 if (next == class1()) return true;
2158 if (next == outer1()) return true;
2159 outer2 = instanceKlassHandle(THREAD, next);
2160 }
2161
2162 // If by this point we have not found an equality between the
2163 // two classes, we know they are in separate package members.
2164 return false;
2165 }
2166
2167
2168 jint instanceKlass::compute_modifier_flags(TRAPS) const {
2169 klassOop k = as_klassOop();
2170 jint access = access_flags().as_int();
2171
2172 // But check if it happens to be member class.
2173 instanceKlassHandle ik(THREAD, k);
2174 InnerClassesIterator iter(ik);
2175 for (; !iter.done(); iter.next()) {
2176 int ioff = iter.inner_class_info_index();
2177 // Inner class attribute can be zero, skip it.
2178 // Strange but true: JVM spec. allows null inner class refs.
2179 if (ioff == 0) continue;
2180
2181 // only look at classes that are already loaded
2182 // since we are looking for the flags for our self.
2183 Symbol* inner_name = ik->constants()->klass_name_at(ioff);
2184 if ((ik->name() == inner_name)) {
2185 // This is really a member class.
2186 access = iter.inner_access_flags();
2187 break;
2188 }
2189 }
2190 // Remember to strip ACC_SUPER bit
2191 return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2192 }
2193
2194 jint instanceKlass::jvmti_class_status() const {
2195 jint result = 0;
2196
2197 if (is_linked()) {
2198 result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2199 }
2200
2201 if (is_initialized()) {
2202 assert(is_linked(), "Class status is not consistent");
2203 result |= JVMTI_CLASS_STATUS_INITIALIZED;
2204 }
2205 if (is_in_error_state()) {
2206 result |= JVMTI_CLASS_STATUS_ERROR;
2207 }
2208 return result;
2209 }
2210
2211 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
2212 itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2213 int method_table_offset_in_words = ioe->offset()/wordSize;
2214 int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2215 / itableOffsetEntry::size();
2216
2217 for (int cnt = 0 ; ; cnt ++, ioe ++) {
2218 // If the interface isn't implemented by the receiver class,
2219 // the VM should throw IncompatibleClassChangeError.
2220 if (cnt >= nof_interfaces) {
2221 THROW_0(vmSymbols::java_lang_IncompatibleClassChangeError());
2222 }
2223
2224 klassOop ik = ioe->interface_klass();
2225 if (ik == holder) break;
2226 }
2227
2228 itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
2229 methodOop m = ime[index].method();
2230 if (m == NULL) {
2231 THROW_0(vmSymbols::java_lang_AbstractMethodError());
2232 }
2233 return m;
2234 }
2235
2236 // On-stack replacement stuff
2237 void instanceKlass::add_osr_nmethod(nmethod* n) {
2238 // only one compilation can be active
2239 NEEDS_CLEANUP
2240 // This is a short non-blocking critical region, so the no safepoint check is ok.
2241 OsrList_lock->lock_without_safepoint_check();
2242 assert(n->is_osr_method(), "wrong kind of nmethod");
2243 n->set_osr_link(osr_nmethods_head());
2244 set_osr_nmethods_head(n);
2245 // Raise the highest osr level if necessary
2246 if (TieredCompilation) {
2247 methodOop m = n->method();
2248 m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2249 }
2250 // Remember to unlock again
2251 OsrList_lock->unlock();
2252
2253 // Get rid of the osr methods for the same bci that have lower levels.
2254 if (TieredCompilation) {
2255 for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2256 nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2257 if (inv != NULL && inv->is_in_use()) {
2258 inv->make_not_entrant();
2259 }
2260 }
2261 }
2262 }
2263
2264
2265 void instanceKlass::remove_osr_nmethod(nmethod* n) {
2266 // This is a short non-blocking critical region, so the no safepoint check is ok.
2267 OsrList_lock->lock_without_safepoint_check();
2268 assert(n->is_osr_method(), "wrong kind of nmethod");
2269 nmethod* last = NULL;
2270 nmethod* cur = osr_nmethods_head();
2271 int max_level = CompLevel_none; // Find the max comp level excluding n
2272 methodOop m = n->method();
2273 // Search for match
2274 while(cur != NULL && cur != n) {
2275 if (TieredCompilation) {
2276 // Find max level before n
2277 max_level = MAX2(max_level, cur->comp_level());
2278 }
2279 last = cur;
2280 cur = cur->osr_link();
2281 }
2282 nmethod* next = NULL;
2283 if (cur == n) {
2284 next = cur->osr_link();
2285 if (last == NULL) {
2286 // Remove first element
2287 set_osr_nmethods_head(next);
2288 } else {
2289 last->set_osr_link(next);
2290 }
2291 }
2292 n->set_osr_link(NULL);
2293 if (TieredCompilation) {
2294 cur = next;
2295 while (cur != NULL) {
2296 // Find max level after n
2297 max_level = MAX2(max_level, cur->comp_level());
2298 cur = cur->osr_link();
2299 }
2300 m->set_highest_osr_comp_level(max_level);
2301 }
2302 // Remember to unlock again
2303 OsrList_lock->unlock();
2304 }
2305
2306 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
2307 // This is a short non-blocking critical region, so the no safepoint check is ok.
2308 OsrList_lock->lock_without_safepoint_check();
2309 nmethod* osr = osr_nmethods_head();
2310 nmethod* best = NULL;
2311 while (osr != NULL) {
2312 assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2313 // There can be a time when a c1 osr method exists but we are waiting
2314 // for a c2 version. When c2 completes its osr nmethod we will trash
2315 // the c1 version and only be able to find the c2 version. However
2316 // while we overflow in the c1 code at back branches we don't want to
2317 // try and switch to the same code as we are already running
2318
2319 if (osr->method() == m &&
2320 (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2321 if (match_level) {
2322 if (osr->comp_level() == comp_level) {
2323 // Found a match - return it.
2324 OsrList_lock->unlock();
2325 return osr;
2326 }
2327 } else {
2328 if (best == NULL || (osr->comp_level() > best->comp_level())) {
2329 if (osr->comp_level() == CompLevel_highest_tier) {
2330 // Found the best possible - return it.
2331 OsrList_lock->unlock();
2332 return osr;
2333 }
2334 best = osr;
2335 }
2336 }
2337 }
2338 osr = osr->osr_link();
2339 }
2340 OsrList_lock->unlock();
2341 if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2342 return best;
2343 }
2344 return NULL;
2345 }
2346
2347 bool instanceKlass::add_member_name(Handle mem_name) {
2348 jweak mem_name_wref = JNIHandles::make_weak_global(mem_name);
2349 MutexLocker ml(MemberNameTable_lock);
2350 DEBUG_ONLY(No_Safepoint_Verifier nsv);
2351
2352 // Check if method has been redefined while taking out MemberNameTable_lock, if so
2353 // return false. We cannot cache obsolete methods. They will crash when the function
2354 // is called!
2355 methodOop method = (methodOop) java_lang_invoke_MemberName::vmtarget(mem_name());
2356 if (method->is_obsolete()) {
2357 return false;
2358 } else if (method->is_old()) {
2359 // Replace method with redefined version
2360 java_lang_invoke_MemberName::set_vmtarget(mem_name(), method_with_idnum(method->method_idnum()));
2361 }
2362
2363 if (_member_names == NULL) {
2364 _member_names = new (ResourceObj::C_HEAP, mtClass) MemberNameTable(idnum_allocated_count());
2365 }
2366 _member_names->add_member_name(mem_name_wref);
2367 return true;
2368 }
2369
2370 // -----------------------------------------------------------------------------------------------------
2371 #ifndef PRODUCT
2372
2373 // Printing
2374
2375 #define BULLET " - "
2376
2377 void FieldPrinter::do_field(fieldDescriptor* fd) {
2378 _st->print(BULLET);
2379 if (_obj == NULL) {
2380 fd->print_on(_st);
2381 _st->cr();
2382 } else {
2383 fd->print_on_for(_st, _obj);
2384 _st->cr();
2385 }
2386 }
2387
2388
2389 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
2390 Klass::oop_print_on(obj, st);
2391
2392 if (as_klassOop() == SystemDictionary::String_klass()) {
2393 typeArrayOop value = java_lang_String::value(obj);
2394 juint offset = java_lang_String::offset(obj);
2395 juint length = java_lang_String::length(obj);
2396 if (value != NULL &&
2397 value->is_typeArray() &&
2398 offset <= (juint) value->length() &&
2399 offset + length <= (juint) value->length()) {
2400 st->print(BULLET"string: ");
2401 Handle h_obj(obj);
2402 java_lang_String::print(h_obj, st);
2403 st->cr();
2404 if (!WizardMode) return; // that is enough
2405 }
2406 }
2407
2408 st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2409 FieldPrinter print_field(st, obj);
2410 do_nonstatic_fields(&print_field);
2411
2412 if (as_klassOop() == SystemDictionary::Class_klass()) {
2413 st->print(BULLET"signature: ");
2414 java_lang_Class::print_signature(obj, st);
2415 st->cr();
2416 klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
2417 st->print(BULLET"fake entry for mirror: ");
2418 mirrored_klass->print_value_on(st);
2419 st->cr();
2420 st->print(BULLET"fake entry resolved_constructor: ");
2421 methodOop ctor = java_lang_Class::resolved_constructor(obj);
2422 ctor->print_value_on(st);
2423 klassOop array_klass = java_lang_Class::array_klass(obj);
2424 st->cr();
2425 st->print(BULLET"fake entry for array: ");
2426 array_klass->print_value_on(st);
2427 st->cr();
2428 st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
2429 st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
2430 klassOop real_klass = java_lang_Class::as_klassOop(obj);
2431 if (real_klass != NULL && real_klass->klass_part()->oop_is_instance()) {
2432 instanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
2433 }
2434 } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2435 st->print(BULLET"signature: ");
2436 java_lang_invoke_MethodType::print_signature(obj, st);
2437 st->cr();
2438 }
2439 }
2440
2441 #endif //PRODUCT
2442
2443 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
2444 st->print("a ");
2445 name()->print_value_on(st);
2446 obj->print_address_on(st);
2447 if (as_klassOop() == SystemDictionary::String_klass()
2448 && java_lang_String::value(obj) != NULL) {
2449 ResourceMark rm;
2450 int len = java_lang_String::length(obj);
2451 int plen = (len < 24 ? len : 12);
2452 char* str = java_lang_String::as_utf8_string(obj, 0, plen);
2453 st->print(" = \"%s\"", str);
2454 if (len > plen)
2455 st->print("...[%d]", len);
2456 } else if (as_klassOop() == SystemDictionary::Class_klass()) {
2457 klassOop k = java_lang_Class::as_klassOop(obj);
2458 st->print(" = ");
2459 if (k != NULL) {
2460 k->print_value_on(st);
2461 } else {
2462 const char* tname = type2name(java_lang_Class::primitive_type(obj));
2463 st->print("%s", tname ? tname : "type?");
2464 }
2465 } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2466 st->print(" = ");
2467 java_lang_invoke_MethodType::print_signature(obj, st);
2468 } else if (java_lang_boxing_object::is_instance(obj)) {
2469 st->print(" = ");
2470 java_lang_boxing_object::print(obj, st);
2471 } else if (as_klassOop() == SystemDictionary::LambdaForm_klass()) {
2472 oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
2473 if (vmentry != NULL) {
2474 st->print(" => ");
2475 vmentry->print_value_on(st);
2476 }
2477 } else if (as_klassOop() == SystemDictionary::MemberName_klass()) {
2478 oop vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
2479 if (vmtarget != NULL) {
2480 st->print(" = ");
2481 vmtarget->print_value_on(st);
2482 } else {
2483 java_lang_invoke_MemberName::clazz(obj)->print_value_on(st);
2484 st->print(".");
2485 java_lang_invoke_MemberName::name(obj)->print_value_on(st);
2486 }
2487 }
2488 }
2489
2490 const char* instanceKlass::internal_name() const {
2491 return external_name();
2492 }
2493
2494 // Verification
2495
2496 class VerifyFieldClosure: public OopClosure {
2497 protected:
2498 template <class T> void do_oop_work(T* p) {
2499 guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
2500 oop obj = oopDesc::load_decode_heap_oop(p);
2501 if (!obj->is_oop_or_null()) {
2502 tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
2503 Universe::print();
2504 guarantee(false, "boom");
2505 }
2506 }
2507 public:
2508 virtual void do_oop(oop* p) { VerifyFieldClosure::do_oop_work(p); }
2509 virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
2510 };
2511
2512 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
2513 Klass::oop_verify_on(obj, st);
2514 VerifyFieldClosure blk;
2515 oop_oop_iterate(obj, &blk);
2516 }
2517
2518 // JNIid class for jfieldIDs only
2519 // Note to reviewers:
2520 // These JNI functions are just moved over to column 1 and not changed
2521 // in the compressed oops workspace.
2522 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
2523 _holder = holder;
2524 _offset = offset;
2525 _next = next;
2526 debug_only(_is_static_field_id = false;)
2527 }
2528
2529
2530 JNIid* JNIid::find(int offset) {
2531 JNIid* current = this;
2532 while (current != NULL) {
2533 if (current->offset() == offset) return current;
2534 current = current->next();
2535 }
2536 return NULL;
2537 }
2538
2539 void JNIid::oops_do(OopClosure* f) {
2540 for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
2541 f->do_oop(cur->holder_addr());
2542 }
2543 }
2544
2545 void JNIid::deallocate(JNIid* current) {
2546 while (current != NULL) {
2547 JNIid* next = current->next();
2548 delete current;
2549 current = next;
2550 }
2551 }
2552
2553
2554 void JNIid::verify(klassOop holder) {
2555 int first_field_offset = instanceMirrorKlass::offset_of_static_fields();
2556 int end_field_offset;
2557 end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
2558
2559 JNIid* current = this;
2560 while (current != NULL) {
2561 guarantee(current->holder() == holder, "Invalid klass in JNIid");
2562 #ifdef ASSERT
2563 int o = current->offset();
2564 if (current->is_static_field_id()) {
2565 guarantee(o >= first_field_offset && o < end_field_offset, "Invalid static field offset in JNIid");
2566 }
2567 #endif
2568 current = current->next();
2569 }
2570 }
2571
2572
2573 #ifdef ASSERT
2574 void instanceKlass::set_init_state(ClassState state) {
2575 bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
2576 : (_init_state < state);
2577 assert(good_state || state == allocated, "illegal state transition");
2578 _init_state = (u1)state;
2579 }
2580 #endif
2581
2582
2583 // RedefineClasses() support for previous versions:
2584
2585 // Add an information node that contains weak references to the
2586 // interesting parts of the previous version of the_class.
2587 // This is also where we clean out any unused weak references.
2588 // Note that while we delete nodes from the _previous_versions
2589 // array, we never delete the array itself until the klass is
2590 // unloaded. The has_been_redefined() query depends on that fact.
2591 //
2592 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
2593 BitMap* emcp_methods, int emcp_method_count) {
2594 assert(Thread::current()->is_VM_thread(),
2595 "only VMThread can add previous versions");
2596
2597 if (_previous_versions == NULL) {
2598 // This is the first previous version so make some space.
2599 // Start with 2 elements under the assumption that the class
2600 // won't be redefined much.
2601 _previous_versions = new (ResourceObj::C_HEAP, mtClass)
2602 GrowableArray<PreviousVersionNode *>(2, true);
2603 }
2604
2605 // RC_TRACE macro has an embedded ResourceMark
2606 RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
2607 ikh->external_name(), _previous_versions->length(), emcp_method_count));
2608 constantPoolHandle cp_h(ikh->constants());
2609 jobject cp_ref;
2610 if (cp_h->is_shared()) {
2611 // a shared ConstantPool requires a regular reference; a weak
2612 // reference would be collectible
2613 cp_ref = JNIHandles::make_global(cp_h);
2614 } else {
2615 cp_ref = JNIHandles::make_weak_global(cp_h);
2616 }
2617 PreviousVersionNode * pv_node = NULL;
2618 objArrayOop old_methods = ikh->methods();
2619
2620 if (emcp_method_count == 0) {
2621 // non-shared ConstantPool gets a weak reference
2622 pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
2623 RC_TRACE(0x00000400,
2624 ("add: all methods are obsolete; flushing any EMCP weak refs"));
2625 } else {
2626 int local_count = 0;
2627 GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP, mtClass)
2628 GrowableArray<jweak>(emcp_method_count, true);
2629 for (int i = 0; i < old_methods->length(); i++) {
2630 if (emcp_methods->at(i)) {
2631 // this old method is EMCP so save a weak ref
2632 methodOop old_method = (methodOop) old_methods->obj_at(i);
2633 methodHandle old_method_h(old_method);
2634 jweak method_ref = JNIHandles::make_weak_global(old_method_h);
2635 method_refs->append(method_ref);
2636 if (++local_count >= emcp_method_count) {
2637 // no more EMCP methods so bail out now
2638 break;
2639 }
2640 }
2641 }
2642 // non-shared ConstantPool gets a weak reference
2643 pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
2644 }
2645
2646 _previous_versions->append(pv_node);
2647
2648 // Using weak references allows the interesting parts of previous
2649 // classes to be GC'ed when they are no longer needed. Since the
2650 // caller is the VMThread and we are at a safepoint, this is a good
2651 // time to clear out unused weak references.
2652
2653 RC_TRACE(0x00000400, ("add: previous version length=%d",
2654 _previous_versions->length()));
2655
2656 // skip the last entry since we just added it
2657 for (int i = _previous_versions->length() - 2; i >= 0; i--) {
2658 // check the previous versions array for a GC'ed weak refs
2659 pv_node = _previous_versions->at(i);
2660 cp_ref = pv_node->prev_constant_pool();
2661 assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2662 if (cp_ref == NULL) {
2663 delete pv_node;
2664 _previous_versions->remove_at(i);
2665 // Since we are traversing the array backwards, we don't have to
2666 // do anything special with the index.
2667 continue; // robustness
2668 }
2669
2670 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2671 if (cp == NULL) {
2672 // this entry has been GC'ed so remove it
2673 delete pv_node;
2674 _previous_versions->remove_at(i);
2675 // Since we are traversing the array backwards, we don't have to
2676 // do anything special with the index.
2677 continue;
2678 } else {
2679 RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
2680 }
2681
2682 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2683 if (method_refs != NULL) {
2684 RC_TRACE(0x00000400, ("add: previous methods length=%d",
2685 method_refs->length()));
2686 for (int j = method_refs->length() - 1; j >= 0; j--) {
2687 jweak method_ref = method_refs->at(j);
2688 assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2689 if (method_ref == NULL) {
2690 method_refs->remove_at(j);
2691 // Since we are traversing the array backwards, we don't have to
2692 // do anything special with the index.
2693 continue; // robustness
2694 }
2695
2696 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2697 if (method == NULL || emcp_method_count == 0) {
2698 // This method entry has been GC'ed or the current
2699 // RedefineClasses() call has made all methods obsolete
2700 // so remove it.
2701 JNIHandles::destroy_weak_global(method_ref);
2702 method_refs->remove_at(j);
2703 } else {
2704 // RC_TRACE macro has an embedded ResourceMark
2705 RC_TRACE(0x00000400,
2706 ("add: %s(%s): previous method @%d in version @%d is alive",
2707 method->name()->as_C_string(), method->signature()->as_C_string(),
2708 j, i));
2709 }
2710 }
2711 }
2712 }
2713
2714 int obsolete_method_count = old_methods->length() - emcp_method_count;
2715
2716 if (emcp_method_count != 0 && obsolete_method_count != 0 &&
2717 _previous_versions->length() > 1) {
2718 // We have a mix of obsolete and EMCP methods. If there is more
2719 // than the previous version that we just added, then we have to
2720 // clear out any matching EMCP method entries the hard way.
2721 int local_count = 0;
2722 for (int i = 0; i < old_methods->length(); i++) {
2723 if (!emcp_methods->at(i)) {
2724 // only obsolete methods are interesting
2725 methodOop old_method = (methodOop) old_methods->obj_at(i);
2726 Symbol* m_name = old_method->name();
2727 Symbol* m_signature = old_method->signature();
2728
2729 // skip the last entry since we just added it
2730 for (int j = _previous_versions->length() - 2; j >= 0; j--) {
2731 // check the previous versions array for a GC'ed weak refs
2732 pv_node = _previous_versions->at(j);
2733 cp_ref = pv_node->prev_constant_pool();
2734 assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2735 if (cp_ref == NULL) {
2736 delete pv_node;
2737 _previous_versions->remove_at(j);
2738 // Since we are traversing the array backwards, we don't have to
2739 // do anything special with the index.
2740 continue; // robustness
2741 }
2742
2743 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2744 if (cp == NULL) {
2745 // this entry has been GC'ed so remove it
2746 delete pv_node;
2747 _previous_versions->remove_at(j);
2748 // Since we are traversing the array backwards, we don't have to
2749 // do anything special with the index.
2750 continue;
2751 }
2752
2753 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2754 if (method_refs == NULL) {
2755 // We have run into a PreviousVersion generation where
2756 // all methods were made obsolete during that generation's
2757 // RedefineClasses() operation. At the time of that
2758 // operation, all EMCP methods were flushed so we don't
2759 // have to go back any further.
2760 //
2761 // A NULL method_refs is different than an empty method_refs.
2762 // We cannot infer any optimizations about older generations
2763 // from an empty method_refs for the current generation.
2764 break;
2765 }
2766
2767 for (int k = method_refs->length() - 1; k >= 0; k--) {
2768 jweak method_ref = method_refs->at(k);
2769 assert(method_ref != NULL,
2770 "weak method ref was unexpectedly cleared");
2771 if (method_ref == NULL) {
2772 method_refs->remove_at(k);
2773 // Since we are traversing the array backwards, we don't
2774 // have to do anything special with the index.
2775 continue; // robustness
2776 }
2777
2778 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2779 if (method == NULL) {
2780 // this method entry has been GC'ed so skip it
2781 JNIHandles::destroy_weak_global(method_ref);
2782 method_refs->remove_at(k);
2783 continue;
2784 }
2785
2786 if (method->name() == m_name &&
2787 method->signature() == m_signature) {
2788 // The current RedefineClasses() call has made all EMCP
2789 // versions of this method obsolete so mark it as obsolete
2790 // and remove the weak ref.
2791 RC_TRACE(0x00000400,
2792 ("add: %s(%s): flush obsolete method @%d in version @%d",
2793 m_name->as_C_string(), m_signature->as_C_string(), k, j));
2794
2795 method->set_is_obsolete();
2796 JNIHandles::destroy_weak_global(method_ref);
2797 method_refs->remove_at(k);
2798 break;
2799 }
2800 }
2801
2802 // The previous loop may not find a matching EMCP method, but
2803 // that doesn't mean that we can optimize and not go any
2804 // further back in the PreviousVersion generations. The EMCP
2805 // method for this generation could have already been GC'ed,
2806 // but there still may be an older EMCP method that has not
2807 // been GC'ed.
2808 }
2809
2810 if (++local_count >= obsolete_method_count) {
2811 // no more obsolete methods so bail out now
2812 break;
2813 }
2814 }
2815 }
2816 }
2817 } // end add_previous_version()
2818
2819
2820 // Determine if instanceKlass has a previous version.
2821 bool instanceKlass::has_previous_version() const {
2822 if (_previous_versions == NULL) {
2823 // no previous versions array so answer is easy
2824 return false;
2825 }
2826
2827 for (int i = _previous_versions->length() - 1; i >= 0; i--) {
2828 // Check the previous versions array for an info node that hasn't
2829 // been GC'ed
2830 PreviousVersionNode * pv_node = _previous_versions->at(i);
2831
2832 jobject cp_ref = pv_node->prev_constant_pool();
2833 assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
2834 if (cp_ref == NULL) {
2835 continue; // robustness
2836 }
2837
2838 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2839 if (cp != NULL) {
2840 // we have at least one previous version
2841 return true;
2842 }
2843
2844 // We don't have to check the method refs. If the constant pool has
2845 // been GC'ed then so have the methods.
2846 }
2847
2848 // all of the underlying nodes' info has been GC'ed
2849 return false;
2850 } // end has_previous_version()
2851
2852 methodOop instanceKlass::method_with_idnum(int idnum) {
2853 methodOop m = NULL;
2854 if (idnum < methods()->length()) {
2855 m = (methodOop) methods()->obj_at(idnum);
2856 }
2857 if (m == NULL || m->method_idnum() != idnum) {
2858 for (int index = 0; index < methods()->length(); ++index) {
2859 m = (methodOop) methods()->obj_at(index);
2860 if (m->method_idnum() == idnum) {
2861 return m;
2862 }
2863 }
2864 }
2865 return m;
2866 }
2867
2868
2869 // Set the annotation at 'idnum' to 'anno'.
2870 // We don't want to create or extend the array if 'anno' is NULL, since that is the
2871 // default value. However, if the array exists and is long enough, we must set NULL values.
2872 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
2873 objArrayOop md = *md_p;
2874 if (md != NULL && md->length() > idnum) {
2875 md->obj_at_put(idnum, anno);
2876 } else if (anno != NULL) {
2877 // create the array
2878 int length = MAX2(idnum+1, (int)_idnum_allocated_count);
2879 md = oopFactory::new_system_objArray(length, Thread::current());
2880 if (*md_p != NULL) {
2881 // copy the existing entries
2882 for (int index = 0; index < (*md_p)->length(); index++) {
2883 md->obj_at_put(index, (*md_p)->obj_at(index));
2884 }
2885 }
2886 set_annotations(md, md_p);
2887 md->obj_at_put(idnum, anno);
2888 } // if no array and idnum isn't included there is nothing to do
2889 }
2890
2891 // Construct a PreviousVersionNode entry for the array hung off
2892 // the instanceKlass.
2893 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
2894 bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
2895
2896 _prev_constant_pool = prev_constant_pool;
2897 _prev_cp_is_weak = prev_cp_is_weak;
2898 _prev_EMCP_methods = prev_EMCP_methods;
2899 }
2900
2901
2902 // Destroy a PreviousVersionNode
2903 PreviousVersionNode::~PreviousVersionNode() {
2904 if (_prev_constant_pool != NULL) {
2905 if (_prev_cp_is_weak) {
2906 JNIHandles::destroy_weak_global(_prev_constant_pool);
2907 } else {
2908 JNIHandles::destroy_global(_prev_constant_pool);
2909 }
2910 }
2911
2912 if (_prev_EMCP_methods != NULL) {
2913 for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
2914 jweak method_ref = _prev_EMCP_methods->at(i);
2915 if (method_ref != NULL) {
2916 JNIHandles::destroy_weak_global(method_ref);
2917 }
2918 }
2919 delete _prev_EMCP_methods;
2920 }
2921 }
2922
2923
2924 // Construct a PreviousVersionInfo entry
2925 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
2926 _prev_constant_pool_handle = constantPoolHandle(); // NULL handle
2927 _prev_EMCP_method_handles = NULL;
2928
2929 jobject cp_ref = pv_node->prev_constant_pool();
2930 assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
2931 if (cp_ref == NULL) {
2932 return; // robustness
2933 }
2934
2935 constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2936 if (cp == NULL) {
2937 // Weak reference has been GC'ed. Since the constant pool has been
2938 // GC'ed, the methods have also been GC'ed.
2939 return;
2940 }
2941
2942 // make the constantPoolOop safe to return
2943 _prev_constant_pool_handle = constantPoolHandle(cp);
2944
2945 GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2946 if (method_refs == NULL) {
2947 // the instanceKlass did not have any EMCP methods
2948 return;
2949 }
2950
2951 _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
2952
2953 int n_methods = method_refs->length();
2954 for (int i = 0; i < n_methods; i++) {
2955 jweak method_ref = method_refs->at(i);
2956 assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2957 if (method_ref == NULL) {
2958 continue; // robustness
2959 }
2960
2961 methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2962 if (method == NULL) {
2963 // this entry has been GC'ed so skip it
2964 continue;
2965 }
2966
2967 // make the methodOop safe to return
2968 _prev_EMCP_method_handles->append(methodHandle(method));
2969 }
2970 }
2971
2972
2973 // Destroy a PreviousVersionInfo
2974 PreviousVersionInfo::~PreviousVersionInfo() {
2975 // Since _prev_EMCP_method_handles is not C-heap allocated, we
2976 // don't have to delete it.
2977 }
2978
2979
2980 // Construct a helper for walking the previous versions array
2981 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
2982 _previous_versions = ik->previous_versions();
2983 _current_index = 0;
2984 // _hm needs no initialization
2985 _current_p = NULL;
2986 }
2987
2988
2989 // Destroy a PreviousVersionWalker
2990 PreviousVersionWalker::~PreviousVersionWalker() {
2991 // Delete the current info just in case the caller didn't walk to
2992 // the end of the previous versions list. No harm if _current_p is
2993 // already NULL.
2994 delete _current_p;
2995
2996 // When _hm is destroyed, all the Handles returned in
2997 // PreviousVersionInfo objects will be destroyed.
2998 // Also, after this destructor is finished it will be
2999 // safe to delete the GrowableArray allocated in the
3000 // PreviousVersionInfo objects.
3001 }
3002
3003
3004 // Return the interesting information for the next previous version
3005 // of the klass. Returns NULL if there are no more previous versions.
3006 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
3007 if (_previous_versions == NULL) {
3008 // no previous versions so nothing to return
3009 return NULL;
3010 }
3011
3012 delete _current_p; // cleanup the previous info for the caller
3013 _current_p = NULL; // reset to NULL so we don't delete same object twice
3014
3015 int length = _previous_versions->length();
3016
3017 while (_current_index < length) {
3018 PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
3019 PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP, mtClass)
3020 PreviousVersionInfo(pv_node);
3021
3022 constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
3023 if (cp_h.is_null()) {
3024 delete pv_info;
3025
3026 // The underlying node's info has been GC'ed so try the next one.
3027 // We don't have to check the methods. If the constant pool has
3028 // GC'ed then so have the methods.
3029 continue;
3030 }
3031
3032 // Found a node with non GC'ed info so return it. The caller will
3033 // need to delete pv_info when they are done with it.
3034 _current_p = pv_info;
3035 return pv_info;
3036 }
3037
3038 // all of the underlying nodes' info has been GC'ed
3039 return NULL;
3040 } // end next_previous_version()