1 /*
2 * Copyright (c) 1997, 2017, 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/dictionary.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "logging/log.hpp"
32 #include "memory/heapInspection.hpp"
33 #include "memory/metadataFactory.hpp"
34 #include "memory/oopFactory.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/instanceKlass.hpp"
37 #include "oops/klass.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/access.inline.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/orderAccess.inline.hpp"
42 #include "trace/traceMacros.hpp"
43 #include "utilities/macros.hpp"
44 #include "utilities/stack.inline.hpp"
45
46 bool Klass::is_cloneable() const {
47 return _access_flags.is_cloneable_fast() ||
48 is_subtype_of(SystemDictionary::Cloneable_klass());
49 }
50
51 void Klass::set_is_cloneable() {
52 if (name() != vmSymbols::java_lang_invoke_MemberName()) {
53 _access_flags.set_is_cloneable_fast();
54 } else {
55 assert(is_final(), "no subclasses allowed");
56 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
57 }
58 }
59
60 void Klass::set_name(Symbol* n) {
61 _name = n;
62 if (_name != NULL) _name->increment_refcount();
63 }
64
65 bool Klass::is_subclass_of(const Klass* k) const {
66 // Run up the super chain and check
67 if (this == k) return true;
68
69 Klass* t = const_cast<Klass*>(this)->super();
70
71 while (t != NULL) {
72 if (t == k) return true;
73 t = t->super();
74 }
75 return false;
76 }
77
78 bool Klass::search_secondary_supers(Klass* k) const {
79 // Put some extra logic here out-of-line, before the search proper.
80 // This cuts down the size of the inline method.
81
82 // This is necessary, since I am never in my own secondary_super list.
83 if (this == k)
84 return true;
85 // Scan the array-of-objects for a match
86 int cnt = secondary_supers()->length();
87 for (int i = 0; i < cnt; i++) {
88 if (secondary_supers()->at(i) == k) {
89 ((Klass*)this)->set_secondary_super_cache(k);
90 return true;
91 }
92 }
93 return false;
94 }
95
96 // Return self, except for abstract classes with exactly 1
97 // implementor. Then return the 1 concrete implementation.
98 Klass *Klass::up_cast_abstract() {
99 Klass *r = this;
100 while( r->is_abstract() ) { // Receiver is abstract?
101 Klass *s = r->subklass(); // Check for exactly 1 subklass
102 if( !s || s->next_sibling() ) // Oops; wrong count; give up
103 return this; // Return 'this' as a no-progress flag
104 r = s; // Loop till find concrete class
105 }
106 return r; // Return the 1 concrete class
107 }
108
109 // Find LCA in class hierarchy
110 Klass *Klass::LCA( Klass *k2 ) {
111 Klass *k1 = this;
112 while( 1 ) {
113 if( k1->is_subtype_of(k2) ) return k2;
114 if( k2->is_subtype_of(k1) ) return k1;
115 k1 = k1->super();
116 k2 = k2->super();
117 }
118 }
119
120
121 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
122 ResourceMark rm(THREAD);
123 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
124 : vmSymbols::java_lang_InstantiationException(), external_name());
125 }
126
127
128 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
129 THROW(vmSymbols::java_lang_ArrayStoreException());
130 }
131
132
133 void Klass::initialize(TRAPS) {
134 ShouldNotReachHere();
135 }
136
137 bool Klass::compute_is_subtype_of(Klass* k) {
138 assert(k->is_klass(), "argument must be a class");
139 return is_subclass_of(k);
140 }
141
142 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
143 #ifdef ASSERT
144 tty->print_cr("Error: find_field called on a klass oop."
145 " Likely error: reflection method does not correctly"
146 " wrap return value in a mirror object.");
147 #endif
148 ShouldNotReachHere();
149 return NULL;
150 }
151
152 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const {
153 #ifdef ASSERT
154 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
155 " Likely error: reflection method does not correctly"
156 " wrap return value in a mirror object.");
157 #endif
158 ShouldNotReachHere();
159 return NULL;
160 }
161
162 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
163 return Metaspace::allocate(loader_data, word_size, /*read_only*/false,
164 MetaspaceObj::ClassType, THREAD);
165 }
166
167 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
168 // which zeros out memory - calloc equivalent.
169 // The constructor is also used from CppVtableCloner,
170 // which doesn't zero out the memory before calling the constructor.
171 // Need to set the _java_mirror field explicitly to not hit an assert that the field
172 // should be NULL before setting it.
173 Klass::Klass() : _prototype_header(markOopDesc::prototype()),
174 _shared_class_path_index(-1),
175 _java_mirror(NULL) {
176
177 _primary_supers[0] = this;
178 set_super_check_offset(in_bytes(primary_supers_offset()));
179 }
180
181 jint Klass::array_layout_helper(BasicType etype) {
182 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
183 // Note that T_ARRAY is not allowed here.
184 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
185 int esize = type2aelembytes(etype);
186 bool isobj = (etype == T_OBJECT);
187 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
188 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
189
190 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
191 assert(layout_helper_is_array(lh), "correct kind");
192 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
193 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
194 assert(layout_helper_header_size(lh) == hsize, "correct decode");
195 assert(layout_helper_element_type(lh) == etype, "correct decode");
196 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
197
198 return lh;
199 }
200
201 bool Klass::can_be_primary_super_slow() const {
202 if (super() == NULL)
203 return true;
204 else if (super()->super_depth() >= primary_super_limit()-1)
205 return false;
206 else
207 return true;
208 }
209
210 void Klass::initialize_supers(Klass* k, TRAPS) {
211 if (FastSuperclassLimit == 0) {
212 // None of the other machinery matters.
213 set_super(k);
214 return;
215 }
216 if (k == NULL) {
217 set_super(NULL);
218 _primary_supers[0] = this;
219 assert(super_depth() == 0, "Object must already be initialized properly");
220 } else if (k != super() || k == SystemDictionary::Object_klass()) {
221 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
222 "initialize this only once to a non-trivial value");
223 set_super(k);
224 Klass* sup = k;
225 int sup_depth = sup->super_depth();
226 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
227 if (!can_be_primary_super_slow())
228 my_depth = primary_super_limit();
229 for (juint i = 0; i < my_depth; i++) {
230 _primary_supers[i] = sup->_primary_supers[i];
231 }
232 Klass* *super_check_cell;
233 if (my_depth < primary_super_limit()) {
234 _primary_supers[my_depth] = this;
235 super_check_cell = &_primary_supers[my_depth];
236 } else {
237 // Overflow of the primary_supers array forces me to be secondary.
238 super_check_cell = &_secondary_super_cache;
239 }
240 set_super_check_offset((address)super_check_cell - (address) this);
241
242 #ifdef ASSERT
243 {
244 juint j = super_depth();
245 assert(j == my_depth, "computed accessor gets right answer");
246 Klass* t = this;
247 while (!t->can_be_primary_super()) {
248 t = t->super();
249 j = t->super_depth();
250 }
251 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
252 assert(primary_super_of_depth(j1) == NULL, "super list padding");
253 }
254 while (t != NULL) {
255 assert(primary_super_of_depth(j) == t, "super list initialization");
256 t = t->super();
257 --j;
258 }
259 assert(j == (juint)-1, "correct depth count");
260 }
261 #endif
262 }
263
264 if (secondary_supers() == NULL) {
265
266 // Now compute the list of secondary supertypes.
267 // Secondaries can occasionally be on the super chain,
268 // if the inline "_primary_supers" array overflows.
269 int extras = 0;
270 Klass* p;
271 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
272 ++extras;
273 }
274
275 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
276
277 // Compute the "real" non-extra secondaries.
278 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras);
279 if (secondaries == NULL) {
280 // secondary_supers set by compute_secondary_supers
281 return;
282 }
283
284 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
285
286 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
287 int i; // Scan for overflow primaries being duplicates of 2nd'arys
288
289 // This happens frequently for very deeply nested arrays: the
290 // primary superclass chain overflows into the secondary. The
291 // secondary list contains the element_klass's secondaries with
292 // an extra array dimension added. If the element_klass's
293 // secondary list already contains some primary overflows, they
294 // (with the extra level of array-ness) will collide with the
295 // normal primary superclass overflows.
296 for( i = 0; i < secondaries->length(); i++ ) {
297 if( secondaries->at(i) == p )
298 break;
299 }
300 if( i < secondaries->length() )
301 continue; // It's a dup, don't put it in
302 primaries->push(p);
303 }
304 // Combine the two arrays into a metadata object to pack the array.
305 // The primaries are added in the reverse order, then the secondaries.
306 int new_length = primaries->length() + secondaries->length();
307 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
308 class_loader_data(), new_length, CHECK);
309 int fill_p = primaries->length();
310 for (int j = 0; j < fill_p; j++) {
311 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
312 }
313 for( int j = 0; j < secondaries->length(); j++ ) {
314 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
315 }
316
317 #ifdef ASSERT
318 // We must not copy any NULL placeholders left over from bootstrap.
319 for (int j = 0; j < s2->length(); j++) {
320 assert(s2->at(j) != NULL, "correct bootstrapping order");
321 }
322 #endif
323
324 set_secondary_supers(s2);
325 }
326 }
327
328 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots) {
329 assert(num_extra_slots == 0, "override for complex klasses");
330 set_secondary_supers(Universe::the_empty_klass_array());
331 return NULL;
332 }
333
334
335 InstanceKlass* Klass::superklass() const {
336 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
337 return _super == NULL ? NULL : InstanceKlass::cast(_super);
338 }
339
340 void Klass::set_subklass(Klass* s) {
341 assert(s != this, "sanity check");
342 _subklass = s;
343 }
344
345 void Klass::set_next_sibling(Klass* s) {
346 assert(s != this, "sanity check");
347 _next_sibling = s;
348 }
349
350 void Klass::append_to_sibling_list() {
351 debug_only(verify();)
352 // add ourselves to superklass' subklass list
353 InstanceKlass* super = superklass();
354 if (super == NULL) return; // special case: class Object
355 assert((!super->is_interface() // interfaces cannot be supers
356 && (super->superklass() == NULL || !is_interface())),
357 "an interface can only be a subklass of Object");
358 Klass* prev_first_subklass = super->subklass();
359 if (prev_first_subklass != NULL) {
360 // set our sibling to be the superklass' previous first subklass
361 set_next_sibling(prev_first_subklass);
362 }
363 // make ourselves the superklass' first subklass
364 super->set_subklass(this);
365 debug_only(verify();)
366 }
367
368 bool Klass::is_loader_alive(BoolObjectClosure* is_alive) {
369 #ifdef ASSERT
370 // The class is alive iff the class loader is alive.
371 oop loader = class_loader();
372 bool loader_alive = (loader == NULL) || is_alive->do_object_b(loader);
373 #endif // ASSERT
374
375 // The class is alive if it's mirror is alive (which should be marked if the
376 // loader is alive) unless it's an anoymous class.
377 bool mirror_alive = is_alive->do_object_b(java_mirror());
378 assert(!mirror_alive || loader_alive, "loader must be alive if the mirror is"
379 " but not the other way around with anonymous classes");
380 return mirror_alive;
381 }
382
383 void Klass::clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses) {
384 if (!ClassUnloading) {
385 return;
386 }
387
388 Klass* root = SystemDictionary::Object_klass();
389 Stack<Klass*, mtGC> stack;
390
391 stack.push(root);
392 while (!stack.is_empty()) {
393 Klass* current = stack.pop();
394
395 assert(current->is_loader_alive(is_alive), "just checking, this should be live");
396
397 // Find and set the first alive subklass
398 Klass* sub = current->subklass();
399 while (sub != NULL && !sub->is_loader_alive(is_alive)) {
400 #ifndef PRODUCT
401 if (log_is_enabled(Trace, class, unload)) {
402 ResourceMark rm;
403 log_trace(class, unload)("unlinking class (subclass): %s", sub->external_name());
404 }
405 #endif
406 sub = sub->next_sibling();
407 }
408 current->set_subklass(sub);
409 if (sub != NULL) {
410 stack.push(sub);
411 }
412
413 // Find and set the first alive sibling
414 Klass* sibling = current->next_sibling();
415 while (sibling != NULL && !sibling->is_loader_alive(is_alive)) {
416 if (log_is_enabled(Trace, class, unload)) {
417 ResourceMark rm;
418 log_trace(class, unload)("[Unlinking class (sibling) %s]", sibling->external_name());
419 }
420 sibling = sibling->next_sibling();
421 }
422 current->set_next_sibling(sibling);
423 if (sibling != NULL) {
424 stack.push(sibling);
425 }
426
427 // Clean the implementors list and method data.
428 if (clean_alive_klasses && current->is_instance_klass()) {
429 InstanceKlass* ik = InstanceKlass::cast(current);
430 ik->clean_weak_instanceklass_links(is_alive);
431
432 // JVMTI RedefineClasses creates previous versions that are not in
433 // the class hierarchy, so process them here.
434 while ((ik = ik->previous_versions()) != NULL) {
435 ik->clean_weak_instanceklass_links(is_alive);
436 }
437 }
438 }
439 }
440
441 void Klass::set_java_mirror(oop m) {
442 KlassAccess<MO_RELEASE>::oop_store_at(this, in_bytes(java_mirror_offset()), m);
443 }
444
445 void Klass::oops_do(OopClosure* cl) {
446 cl->do_oop(&_java_mirror);
447 }
448
449 void Klass::remove_unshareable_info() {
450 assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
451 TRACE_REMOVE_ID(this);
452
453 set_subklass(NULL);
454 set_next_sibling(NULL);
455 // Clear the java mirror
456 set_java_mirror(NULL);
457 set_next_link(NULL);
458
459 // Null out class_loader_data because we don't share that yet.
460 set_class_loader_data(NULL);
461 }
462
463 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
464 assert(is_klass(), "ensure C++ vtable is restored");
465 TRACE_RESTORE_ID(this);
466
467 // If an exception happened during CDS restore, some of these fields may already be
468 // set. We leave the class on the CLD list, even if incomplete so that we don't
469 // modify the CLD list outside a safepoint.
470 if (class_loader_data() == NULL) {
471 // Restore class_loader_data to the null class loader data
472 set_class_loader_data(loader_data);
473
474 // Add to null class loader list first before creating the mirror
475 // (same order as class file parsing)
476 loader_data->add_class(this);
477 }
478
479 // Recreate the class mirror.
480 // Only recreate it if not present. A previous attempt to restore may have
481 // gotten an OOM later but keep the mirror if it was created.
482 if (java_mirror() == NULL) {
483 Handle loader(THREAD, loader_data->class_loader());
484 ModuleEntry* module_entry = NULL;
485 Klass* k = this;
486 if (k->is_objArray_klass()) {
487 k = ObjArrayKlass::cast(k)->bottom_klass();
488 }
489 // Obtain klass' module.
490 if (k->is_instance_klass()) {
491 InstanceKlass* ik = (InstanceKlass*) k;
492 module_entry = ik->module();
493 } else {
494 module_entry = ModuleEntryTable::javabase_moduleEntry();
495 }
496 // Obtain java.lang.Module, if available
497 Handle module_handle(THREAD, ((module_entry != NULL) ? JNIHandles::resolve(module_entry->module()) : (oop)NULL));
498 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
499 }
500 }
501
502 Klass* Klass::array_klass_or_null(int rank) {
503 EXCEPTION_MARK;
504 // No exception can be thrown by array_klass_impl when called with or_null == true.
505 // (In anycase, the execption mark will fail if it do so)
506 return array_klass_impl(true, rank, THREAD);
507 }
508
509
510 Klass* Klass::array_klass_or_null() {
511 EXCEPTION_MARK;
512 // No exception can be thrown by array_klass_impl when called with or_null == true.
513 // (In anycase, the execption mark will fail if it do so)
514 return array_klass_impl(true, THREAD);
515 }
516
517
518 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
519 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
520 return NULL;
521 }
522
523
524 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
525 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
526 return NULL;
527 }
528
529 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
530
531 oop* Klass::klass_holder_addr() const {
532 return class_loader_data()->class_loader_addr();
533 }
534
535 oop Klass::klass_holder() const {
536 return RootAccess<GC_ACCESS_ON_PHANTOM>::oop_load(klass_holder_addr());
537 }
538
539 // In product mode, this function doesn't have virtual function calls so
540 // there might be some performance advantage to handling InstanceKlass here.
541 const char* Klass::external_name() const {
542 if (is_instance_klass()) {
543 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
544 if (ik->is_anonymous()) {
545 intptr_t hash = 0;
546 if (ik->java_mirror() != NULL) {
547 // java_mirror might not be created yet, return 0 as hash.
548 hash = ik->java_mirror()->identity_hash();
549 }
550 char hash_buf[40];
551 sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);
552 size_t hash_len = strlen(hash_buf);
553
554 size_t result_len = name()->utf8_length();
555 char* result = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);
556 name()->as_klass_external_name(result, (int) result_len + 1);
557 assert(strlen(result) == result_len, "");
558 strcpy(result + result_len, hash_buf);
559 assert(strlen(result) == result_len + hash_len, "");
560 return result;
561 }
562 }
563 if (name() == NULL) return "<unknown>";
564 return name()->as_klass_external_name();
565 }
566
567
568 const char* Klass::signature_name() const {
569 if (name() == NULL) return "<unknown>";
570 return name()->as_C_string();
571 }
572
573 // Unless overridden, modifier_flags is 0.
574 jint Klass::compute_modifier_flags(TRAPS) const {
575 return 0;
576 }
577
578 int Klass::atomic_incr_biased_lock_revocation_count() {
579 return (int) Atomic::add(1, &_biased_lock_revocation_count);
580 }
581
582 // Unless overridden, jvmti_class_status has no flags set.
583 jint Klass::jvmti_class_status() const {
584 return 0;
585 }
586
587
588 // Printing
589
590 void Klass::print_on(outputStream* st) const {
591 ResourceMark rm;
592 // print title
593 st->print("%s", internal_name());
594 print_address_on(st);
595 st->cr();
596 }
597
598 void Klass::oop_print_on(oop obj, outputStream* st) {
599 ResourceMark rm;
600 // print title
601 st->print_cr("%s ", internal_name());
602 obj->print_address_on(st);
603
604 if (WizardMode) {
605 // print header
606 obj->mark()->print_on(st);
607 }
608
609 // print class
610 st->print(" - klass: ");
611 obj->klass()->print_value_on(st);
612 st->cr();
613 }
614
615 void Klass::oop_print_value_on(oop obj, outputStream* st) {
616 // print title
617 ResourceMark rm; // Cannot print in debug mode without this
618 st->print("%s", internal_name());
619 obj->print_address_on(st);
620 }
621
622 #if INCLUDE_SERVICES
623 // Size Statistics
624 void Klass::collect_statistics(KlassSizeStats *sz) const {
625 sz->_klass_bytes = sz->count(this);
626 sz->_mirror_bytes = sz->count(java_mirror());
627 sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
628
629 sz->_ro_bytes += sz->_secondary_supers_bytes;
630 sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
631 }
632 #endif // INCLUDE_SERVICES
633
634 // Verification
635
636 void Klass::verify_on(outputStream* st) {
637
638 // This can be expensive, but it is worth checking that this klass is actually
639 // in the CLD graph but not in production.
640 assert(Metaspace::contains((address)this), "Should be");
641
642 guarantee(this->is_klass(),"should be klass");
643
644 if (super() != NULL) {
645 guarantee(super()->is_klass(), "should be klass");
646 }
647 if (secondary_super_cache() != NULL) {
648 Klass* ko = secondary_super_cache();
649 guarantee(ko->is_klass(), "should be klass");
650 }
651 for ( uint i = 0; i < primary_super_limit(); i++ ) {
652 Klass* ko = _primary_supers[i];
653 if (ko != NULL) {
654 guarantee(ko->is_klass(), "should be klass");
655 }
656 }
657
658 if (java_mirror() != NULL) {
659 guarantee(java_mirror()->is_oop(), "should be instance");
660 }
661 }
662
663 void Klass::oop_verify_on(oop obj, outputStream* st) {
664 guarantee(obj->is_oop(), "should be oop");
665 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
666 }
667
668 klassVtable Klass::vtable() const {
669 return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
670 }
671
672 vtableEntry* Klass::start_of_vtable() const {
673 return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
674 }
675
676 Method* Klass::method_at_vtable(int index) {
677 #ifndef PRODUCT
678 assert(index >= 0, "valid vtable index");
679 if (DebugVtables) {
680 verify_vtable_index(index);
681 }
682 #endif
683 return start_of_vtable()[index].method();
684 }
685
686 ByteSize Klass::vtable_start_offset() {
687 return in_ByteSize(InstanceKlass::header_size() * wordSize);
688 }
689
690 #ifndef PRODUCT
691
692 bool Klass::verify_vtable_index(int i) {
693 int limit = vtable_length()/vtableEntry::size();
694 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
695 return true;
696 }
697
698 bool Klass::verify_itable_index(int i) {
699 assert(is_instance_klass(), "");
700 int method_count = klassItable::method_count_for_interface(this);
701 assert(i >= 0 && i < method_count, "index out of bounds");
702 return true;
703 }
704
705 #endif