1 /*
2 * Copyright (c) 1997, 2018, 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/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "logging/log.hpp"
33 #include "memory/heapInspection.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceClosure.hpp"
36 #include "memory/metaspaceShared.hpp"
37 #include "memory/oopFactory.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/compressedOops.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/oopHandle.inline.hpp"
44 #include "runtime/atomic.hpp"
45 #include "runtime/handles.inline.hpp"
46 #include "runtime/orderAccess.hpp"
47 #include "utilities/macros.hpp"
48 #include "utilities/stack.inline.hpp"
49
50 void Klass::set_java_mirror(Handle m) {
51 assert(!m.is_null(), "New mirror should never be null.");
52 assert(_java_mirror.resolve() == NULL, "should only be used to initialize mirror");
53 _java_mirror = class_loader_data()->add_handle(m);
54 }
55
56 oop Klass::java_mirror() const {
57 return _java_mirror.resolve();
58 }
59
60 bool Klass::is_cloneable() const {
61 return _access_flags.is_cloneable_fast() ||
62 is_subtype_of(SystemDictionary::Cloneable_klass());
63 }
64
65 void Klass::set_is_cloneable() {
66 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
67 assert(is_final(), "no subclasses allowed");
68 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
69 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
70 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
71 } else {
72 _access_flags.set_is_cloneable_fast();
73 }
74 }
75
76 void Klass::set_name(Symbol* n) {
77 _name = n;
78 if (_name != NULL) _name->increment_refcount();
79 }
80
81 bool Klass::is_subclass_of(const Klass* k) const {
82 // Run up the super chain and check
83 if (this == k) return true;
84
85 Klass* t = const_cast<Klass*>(this)->super();
86
87 while (t != NULL) {
88 if (t == k) return true;
89 t = t->super();
90 }
91 return false;
92 }
93
94 bool Klass::search_secondary_supers(Klass* k) const {
95 // Put some extra logic here out-of-line, before the search proper.
96 // This cuts down the size of the inline method.
97
98 // This is necessary, since I am never in my own secondary_super list.
99 if (this == k)
100 return true;
101 // Scan the array-of-objects for a match
102 int cnt = secondary_supers()->length();
103 for (int i = 0; i < cnt; i++) {
104 if (secondary_supers()->at(i) == k) {
105 ((Klass*)this)->set_secondary_super_cache(k);
106 return true;
107 }
108 }
109 return false;
110 }
111
112 // Return self, except for abstract classes with exactly 1
113 // implementor. Then return the 1 concrete implementation.
114 Klass *Klass::up_cast_abstract() {
115 Klass *r = this;
116 while( r->is_abstract() ) { // Receiver is abstract?
117 Klass *s = r->subklass(); // Check for exactly 1 subklass
118 if( !s || s->next_sibling() ) // Oops; wrong count; give up
119 return this; // Return 'this' as a no-progress flag
120 r = s; // Loop till find concrete class
121 }
122 return r; // Return the 1 concrete class
123 }
124
125 // Find LCA in class hierarchy
126 Klass *Klass::LCA( Klass *k2 ) {
127 Klass *k1 = this;
128 while( 1 ) {
129 if( k1->is_subtype_of(k2) ) return k2;
130 if( k2->is_subtype_of(k1) ) return k1;
131 k1 = k1->super();
132 k2 = k2->super();
133 }
134 }
135
136
137 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
138 ResourceMark rm(THREAD);
139 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
140 : vmSymbols::java_lang_InstantiationException(), external_name());
141 }
142
143
144 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
145 ResourceMark rm(THREAD);
146 assert(s != NULL, "Throw NPE!");
147 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
148 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
149 }
150
151
152 void Klass::initialize(TRAPS) {
153 ShouldNotReachHere();
154 }
155
156 bool Klass::compute_is_subtype_of(Klass* k) {
157 assert(k->is_klass(), "argument must be a class");
158 return is_subclass_of(k);
159 }
160
161 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
162 #ifdef ASSERT
163 tty->print_cr("Error: find_field called on a klass oop."
164 " Likely error: reflection method does not correctly"
165 " wrap return value in a mirror object.");
166 #endif
167 ShouldNotReachHere();
168 return NULL;
169 }
170
171 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
172 OverpassLookupMode overpass_mode,
173 PrivateLookupMode private_mode) const {
174 #ifdef ASSERT
175 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
176 " Likely error: reflection method does not correctly"
177 " wrap return value in a mirror object.");
178 #endif
179 ShouldNotReachHere();
180 return NULL;
181 }
182
183 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
184 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
185 }
186
187 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
188 // which zeros out memory - calloc equivalent.
189 // The constructor is also used from CppVtableCloner,
190 // which doesn't zero out the memory before calling the constructor.
191 // Need to set the _java_mirror field explicitly to not hit an assert that the field
192 // should be NULL before setting it.
193 Klass::Klass(KlassID id) : _id(id),
194 _prototype_header(markOopDesc::prototype()),
195 _shared_class_path_index(-1),
196 _java_mirror(NULL) {
197 CDS_ONLY(_shared_class_flags = 0;)
198 CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
199 _primary_supers[0] = this;
200 set_super_check_offset(in_bytes(primary_supers_offset()));
201 }
202
203 jint Klass::array_layout_helper(BasicType etype) {
204 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
205 // Note that T_ARRAY is not allowed here.
206 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
207 int esize = type2aelembytes(etype);
208 bool isobj = (etype == T_OBJECT);
209 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
210 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
211
212 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
213 assert(layout_helper_is_array(lh), "correct kind");
214 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
215 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
216 assert(layout_helper_header_size(lh) == hsize, "correct decode");
217 assert(layout_helper_element_type(lh) == etype, "correct decode");
218 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
219
220 return lh;
221 }
222
223 bool Klass::can_be_primary_super_slow() const {
224 if (super() == NULL)
225 return true;
226 else if (super()->super_depth() >= primary_super_limit()-1)
227 return false;
228 else
229 return true;
230 }
231
232 void Klass::initialize_supers(Klass* k, Array<Klass*>* transitive_interfaces, TRAPS) {
233 if (FastSuperclassLimit == 0) {
234 // None of the other machinery matters.
235 set_super(k);
236 return;
237 }
238 if (k == NULL) {
239 set_super(NULL);
240 _primary_supers[0] = this;
241 assert(super_depth() == 0, "Object must already be initialized properly");
242 } else if (k != super() || k == SystemDictionary::Object_klass()) {
243 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
244 "initialize this only once to a non-trivial value");
245 set_super(k);
246 Klass* sup = k;
247 int sup_depth = sup->super_depth();
248 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
249 if (!can_be_primary_super_slow())
250 my_depth = primary_super_limit();
251 for (juint i = 0; i < my_depth; i++) {
252 _primary_supers[i] = sup->_primary_supers[i];
253 }
254 Klass* *super_check_cell;
255 if (my_depth < primary_super_limit()) {
256 _primary_supers[my_depth] = this;
257 super_check_cell = &_primary_supers[my_depth];
258 } else {
259 // Overflow of the primary_supers array forces me to be secondary.
260 super_check_cell = &_secondary_super_cache;
261 }
262 set_super_check_offset((address)super_check_cell - (address) this);
263
264 #ifdef ASSERT
265 {
266 juint j = super_depth();
267 assert(j == my_depth, "computed accessor gets right answer");
268 Klass* t = this;
269 while (!t->can_be_primary_super()) {
270 t = t->super();
271 j = t->super_depth();
272 }
273 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
274 assert(primary_super_of_depth(j1) == NULL, "super list padding");
275 }
276 while (t != NULL) {
277 assert(primary_super_of_depth(j) == t, "super list initialization");
278 t = t->super();
279 --j;
280 }
281 assert(j == (juint)-1, "correct depth count");
282 }
283 #endif
284 }
285
286 if (secondary_supers() == NULL) {
287
288 // Now compute the list of secondary supertypes.
289 // Secondaries can occasionally be on the super chain,
290 // if the inline "_primary_supers" array overflows.
291 int extras = 0;
292 Klass* p;
293 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
294 ++extras;
295 }
296
297 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
298
299 // Compute the "real" non-extra secondaries.
300 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
301 if (secondaries == NULL) {
302 // secondary_supers set by compute_secondary_supers
303 return;
304 }
305
306 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
307
308 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
309 int i; // Scan for overflow primaries being duplicates of 2nd'arys
310
311 // This happens frequently for very deeply nested arrays: the
312 // primary superclass chain overflows into the secondary. The
313 // secondary list contains the element_klass's secondaries with
314 // an extra array dimension added. If the element_klass's
315 // secondary list already contains some primary overflows, they
316 // (with the extra level of array-ness) will collide with the
317 // normal primary superclass overflows.
318 for( i = 0; i < secondaries->length(); i++ ) {
319 if( secondaries->at(i) == p )
320 break;
321 }
322 if( i < secondaries->length() )
323 continue; // It's a dup, don't put it in
324 primaries->push(p);
325 }
326 // Combine the two arrays into a metadata object to pack the array.
327 // The primaries are added in the reverse order, then the secondaries.
328 int new_length = primaries->length() + secondaries->length();
329 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
330 class_loader_data(), new_length, CHECK);
331 int fill_p = primaries->length();
332 for (int j = 0; j < fill_p; j++) {
333 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
334 }
335 for( int j = 0; j < secondaries->length(); j++ ) {
336 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
337 }
338
339 #ifdef ASSERT
340 // We must not copy any NULL placeholders left over from bootstrap.
341 for (int j = 0; j < s2->length(); j++) {
342 assert(s2->at(j) != NULL, "correct bootstrapping order");
343 }
344 #endif
345
346 set_secondary_supers(s2);
347 }
348 }
349
350 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
351 Array<Klass*>* transitive_interfaces) {
352 assert(num_extra_slots == 0, "override for complex klasses");
353 assert(transitive_interfaces == NULL, "sanity");
354 set_secondary_supers(Universe::the_empty_klass_array());
355 return NULL;
356 }
357
358
359 InstanceKlass* Klass::superklass() const {
360 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
361 return _super == NULL ? NULL : InstanceKlass::cast(_super);
362 }
363
364 void Klass::set_subklass(Klass* s) {
365 assert(s != this, "sanity check");
366 _subklass = s;
367 }
368
369 void Klass::set_next_sibling(Klass* s) {
370 assert(s != this, "sanity check");
371 _next_sibling = s;
372 }
373
374 void Klass::append_to_sibling_list() {
375 debug_only(verify();)
376 // add ourselves to superklass' subklass list
377 InstanceKlass* super = superklass();
378 if (super == NULL) return; // special case: class Object
379 assert((!super->is_interface() // interfaces cannot be supers
380 && (super->superklass() == NULL || !is_interface())),
381 "an interface can only be a subklass of Object");
382 Klass* prev_first_subklass = super->subklass();
383 if (prev_first_subklass != NULL) {
384 // set our sibling to be the superklass' previous first subklass
385 set_next_sibling(prev_first_subklass);
386 }
387 // make ourselves the superklass' first subklass
388 super->set_subklass(this);
389 debug_only(verify();)
390 }
391
392 oop Klass::holder_phantom() const {
393 return class_loader_data()->holder_phantom();
394 }
395
396 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
397 if (!ClassUnloading || !unloading_occurred) {
398 return;
399 }
400
401 Klass* root = SystemDictionary::Object_klass();
402 Stack<Klass*, mtGC> stack;
403
404 stack.push(root);
405 while (!stack.is_empty()) {
406 Klass* current = stack.pop();
407
408 assert(current->is_loader_alive(), "just checking, this should be live");
409
410 // Find and set the first alive subklass
411 Klass* sub = current->subklass();
412 while (sub != NULL && !sub->is_loader_alive()) {
413 #ifndef PRODUCT
414 if (log_is_enabled(Trace, class, unload)) {
415 ResourceMark rm;
416 log_trace(class, unload)("unlinking class (subclass): %s", sub->external_name());
417 }
418 #endif
419 sub = sub->next_sibling();
420 }
421 current->set_subklass(sub);
422 if (sub != NULL) {
423 stack.push(sub);
424 }
425
426 // Find and set the first alive sibling
427 Klass* sibling = current->next_sibling();
428 while (sibling != NULL && !sibling->is_loader_alive()) {
429 if (log_is_enabled(Trace, class, unload)) {
430 ResourceMark rm;
431 log_trace(class, unload)("[Unlinking class (sibling) %s]", sibling->external_name());
432 }
433 sibling = sibling->next_sibling();
434 }
435 current->set_next_sibling(sibling);
436 if (sibling != NULL) {
437 stack.push(sibling);
438 }
439
440 // Clean the implementors list and method data.
441 if (clean_alive_klasses && current->is_instance_klass()) {
442 InstanceKlass* ik = InstanceKlass::cast(current);
443 ik->clean_weak_instanceklass_links();
444
445 // JVMTI RedefineClasses creates previous versions that are not in
446 // the class hierarchy, so process them here.
447 while ((ik = ik->previous_versions()) != NULL) {
448 ik->clean_weak_instanceklass_links();
449 }
450 }
451 }
452 }
453
454 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
455 if (log_is_enabled(Trace, cds)) {
456 ResourceMark rm;
457 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
458 }
459
460 it->push(&_name);
461 it->push(&_secondary_super_cache);
462 it->push(&_secondary_supers);
463 for (int i = 0; i < _primary_super_limit; i++) {
464 it->push(&_primary_supers[i]);
465 }
466 it->push(&_super);
467 it->push(&_subklass);
468 it->push(&_next_sibling);
469 it->push(&_next_link);
470
471 vtableEntry* vt = start_of_vtable();
472 for (int i=0; i<vtable_length(); i++) {
473 it->push(vt[i].method_addr());
474 }
475 }
476
477 void Klass::remove_unshareable_info() {
478 assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
479 JFR_ONLY(REMOVE_ID(this);)
480 if (log_is_enabled(Trace, cds, unshareable)) {
481 ResourceMark rm;
482 log_trace(cds, unshareable)("remove: %s", external_name());
483 }
484
485 set_subklass(NULL);
486 set_next_sibling(NULL);
487 set_next_link(NULL);
488
489 // Null out class_loader_data because we don't share that yet.
490 set_class_loader_data(NULL);
491 set_is_shared();
492 }
493
494 void Klass::remove_java_mirror() {
495 assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
496 if (log_is_enabled(Trace, cds, unshareable)) {
497 ResourceMark rm;
498 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
499 }
500 // Just null out the mirror. The class_loader_data() no longer exists.
501 _java_mirror = NULL;
502 }
503
504 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
505 assert(is_klass(), "ensure C++ vtable is restored");
506 assert(is_shared(), "must be set");
507 JFR_ONLY(RESTORE_ID(this);)
508 if (log_is_enabled(Trace, cds, unshareable)) {
509 ResourceMark rm;
510 log_trace(cds, unshareable)("restore: %s", external_name());
511 }
512
513 // If an exception happened during CDS restore, some of these fields may already be
514 // set. We leave the class on the CLD list, even if incomplete so that we don't
515 // modify the CLD list outside a safepoint.
516 if (class_loader_data() == NULL) {
517 // Restore class_loader_data to the null class loader data
518 set_class_loader_data(loader_data);
519
520 // Add to null class loader list first before creating the mirror
521 // (same order as class file parsing)
522 loader_data->add_class(this);
523 }
524
525 Handle loader(THREAD, loader_data->class_loader());
526 ModuleEntry* module_entry = NULL;
527 Klass* k = this;
528 if (k->is_objArray_klass()) {
529 k = ObjArrayKlass::cast(k)->bottom_klass();
530 }
531 // Obtain klass' module.
532 if (k->is_instance_klass()) {
533 InstanceKlass* ik = (InstanceKlass*) k;
534 module_entry = ik->module();
535 } else {
536 module_entry = ModuleEntryTable::javabase_moduleEntry();
537 }
538 // Obtain java.lang.Module, if available
539 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
540
541 if (this->has_raw_archived_mirror()) {
542 ResourceMark rm;
543 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
544 if (MetaspaceShared::open_archive_heap_region_mapped()) {
545 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
546 protection_domain,
547 CHECK);
548 if (present) {
549 return;
550 }
551 }
552
553 // No archived mirror data
554 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
555 _java_mirror = NULL;
556 this->clear_has_raw_archived_mirror();
557 }
558
559 // Only recreate it if not present. A previous attempt to restore may have
560 // gotten an OOM later but keep the mirror if it was created.
561 if (java_mirror() == NULL) {
562 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
563 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
564 }
565 }
566
567 #if INCLUDE_CDS_JAVA_HEAP
568 // Used at CDS dump time to access the archived mirror. No GC barrier.
569 oop Klass::archived_java_mirror_raw() {
570 assert(has_raw_archived_mirror(), "must have raw archived mirror");
571 return CompressedOops::decode(_archived_mirror);
572 }
573
574 // No GC barrier
575 void Klass::set_archived_java_mirror_raw(oop m) {
576 assert(DumpSharedSpaces, "called only during runtime");
577 _archived_mirror = CompressedOops::encode(m);
578 }
579 #endif // INCLUDE_CDS_JAVA_HEAP
580
581 Klass* Klass::array_klass_or_null(int rank) {
582 EXCEPTION_MARK;
583 // No exception can be thrown by array_klass_impl when called with or_null == true.
584 // (In anycase, the execption mark will fail if it do so)
585 return array_klass_impl(true, rank, THREAD);
586 }
587
588
589 Klass* Klass::array_klass_or_null() {
590 EXCEPTION_MARK;
591 // No exception can be thrown by array_klass_impl when called with or_null == true.
592 // (In anycase, the execption mark will fail if it do so)
593 return array_klass_impl(true, THREAD);
594 }
595
596
597 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
598 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
599 return NULL;
600 }
601
602
603 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
604 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
605 return NULL;
606 }
607
608 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
609
610 // In product mode, this function doesn't have virtual function calls so
611 // there might be some performance advantage to handling InstanceKlass here.
612 const char* Klass::external_name() const {
613 if (is_instance_klass()) {
614 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
615 if (ik->is_anonymous()) {
616 char addr_buf[20];
617 jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
618 size_t addr_len = strlen(addr_buf);
619 size_t name_len = name()->utf8_length();
620 char* result = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
621 name()->as_klass_external_name(result, (int) name_len + 1);
622 assert(strlen(result) == name_len, "");
623 strcpy(result + name_len, addr_buf);
624 assert(strlen(result) == name_len + addr_len, "");
625 return result;
626 }
627 }
628 if (name() == NULL) return "<unknown>";
629 return name()->as_klass_external_name();
630 }
631
632 const char* Klass::signature_name() const {
633 if (name() == NULL) return "<unknown>";
634 return name()->as_C_string();
635 }
636
637 const char* Klass::external_kind() const {
638 if (is_interface()) return "interface";
639 if (is_abstract()) return "abstract class";
640 return "class";
641 }
642
643 // Unless overridden, modifier_flags is 0.
644 jint Klass::compute_modifier_flags(TRAPS) const {
645 return 0;
646 }
647
648 int Klass::atomic_incr_biased_lock_revocation_count() {
649 return (int) Atomic::add(1, &_biased_lock_revocation_count);
650 }
651
652 // Unless overridden, jvmti_class_status has no flags set.
653 jint Klass::jvmti_class_status() const {
654 return 0;
655 }
656
657
658 // Printing
659
660 void Klass::print_on(outputStream* st) const {
661 ResourceMark rm;
662 // print title
663 st->print("%s", internal_name());
664 print_address_on(st);
665 st->cr();
666 }
667
668 void Klass::oop_print_on(oop obj, outputStream* st) {
669 ResourceMark rm;
670 // print title
671 st->print_cr("%s ", internal_name());
672 obj->print_address_on(st);
673
674 if (WizardMode) {
675 // print header
676 obj->mark()->print_on(st);
677 }
678
679 // print class
680 st->print(" - klass: ");
681 obj->klass()->print_value_on(st);
682 st->cr();
683 }
684
685 void Klass::oop_print_value_on(oop obj, outputStream* st) {
686 // print title
687 ResourceMark rm; // Cannot print in debug mode without this
688 st->print("%s", internal_name());
689 obj->print_address_on(st);
690 }
691
692 #if INCLUDE_SERVICES
693 // Size Statistics
694 void Klass::collect_statistics(KlassSizeStats *sz) const {
695 sz->_klass_bytes = sz->count(this);
696 sz->_mirror_bytes = sz->count(java_mirror());
697 sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
698
699 sz->_ro_bytes += sz->_secondary_supers_bytes;
700 sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
701 }
702 #endif // INCLUDE_SERVICES
703
704 // Verification
705
706 void Klass::verify_on(outputStream* st) {
707
708 // This can be expensive, but it is worth checking that this klass is actually
709 // in the CLD graph but not in production.
710 assert(Metaspace::contains((address)this), "Should be");
711
712 guarantee(this->is_klass(),"should be klass");
713
714 if (super() != NULL) {
715 guarantee(super()->is_klass(), "should be klass");
716 }
717 if (secondary_super_cache() != NULL) {
718 Klass* ko = secondary_super_cache();
719 guarantee(ko->is_klass(), "should be klass");
720 }
721 for ( uint i = 0; i < primary_super_limit(); i++ ) {
722 Klass* ko = _primary_supers[i];
723 if (ko != NULL) {
724 guarantee(ko->is_klass(), "should be klass");
725 }
726 }
727
728 if (java_mirror() != NULL) {
729 guarantee(oopDesc::is_oop(java_mirror()), "should be instance");
730 }
731 }
732
733 void Klass::oop_verify_on(oop obj, outputStream* st) {
734 guarantee(oopDesc::is_oop(obj), "should be oop");
735 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
736 }
737
738 klassVtable Klass::vtable() const {
739 return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
740 }
741
742 vtableEntry* Klass::start_of_vtable() const {
743 return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
744 }
745
746 Method* Klass::method_at_vtable(int index) {
747 #ifndef PRODUCT
748 assert(index >= 0, "valid vtable index");
749 if (DebugVtables) {
750 verify_vtable_index(index);
751 }
752 #endif
753 return start_of_vtable()[index].method();
754 }
755
756 ByteSize Klass::vtable_start_offset() {
757 return in_ByteSize(InstanceKlass::header_size() * wordSize);
758 }
759
760 #ifndef PRODUCT
761
762 bool Klass::verify_vtable_index(int i) {
763 int limit = vtable_length()/vtableEntry::size();
764 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
765 return true;
766 }
767
768 bool Klass::verify_itable_index(int i) {
769 assert(is_instance_klass(), "");
770 int method_count = klassItable::method_count_for_interface(this);
771 assert(i >= 0 && i < method_count, "index out of bounds");
772 return true;
773 }
774
775 #endif // PRODUCT
776
777 // Caller needs ResourceMark
778 // joint_in_module_of_loader provides an optimization if 2 classes are in
779 // the same module to succinctly print out relevant information about their
780 // module name and class loader's name_and_id for error messages.
781 // Format:
782 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
783 // are in module <module-name>[@<version>]
784 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
785 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
786 assert(module() == class2->module(), "classes do not have the same module");
787 const char* class1_name = external_name();
788 size_t len = strlen(class1_name) + 1;
789
790 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
791 len += strlen(class2_description);
792
793 len += strlen(" and ");
794
795 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
796
797 // Just return the FQN if error when allocating string
798 if (joint_description == NULL) {
799 return class1_name;
800 }
801
802 jio_snprintf(joint_description, len, "%s and %s",
803 class1_name,
804 class2_description);
805
806 return joint_description;
807 }
808
809 // Caller needs ResourceMark
810 // class_in_module_of_loader provides a standard way to include
811 // relevant information about a class, such as its module name as
812 // well as its class loader's name_and_id, in error messages and logging.
813 // Format:
814 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
815 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
816 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
817 // 1. fully qualified external name of class
818 const char* klass_name = external_name();
819 size_t len = strlen(klass_name) + 1;
820
821 // 2. module name + @version
822 const char* module_name = "";
823 const char* version = "";
824 bool has_version = false;
825 bool module_is_named = false;
826 const char* module_name_phrase = "";
827 const Klass* bottom_klass = is_objArray_klass() ?
828 ObjArrayKlass::cast(this)->bottom_klass() : this;
829 if (bottom_klass->is_instance_klass()) {
830 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
831 if (module->is_named()) {
832 module_is_named = true;
833 module_name_phrase = "module ";
834 module_name = module->name()->as_C_string();
835 len += strlen(module_name);
836 // Use version if exists and is not a jdk module
837 if (module->should_show_version()) {
838 has_version = true;
839 version = module->version()->as_C_string();
840 // Include stlen(version) + 1 for the "@"
841 len += strlen(version) + 1;
842 }
843 } else {
844 module_name = UNNAMED_MODULE;
845 len += UNNAMED_MODULE_LEN;
846 }
847 } else {
848 // klass is an array of primitives, module is java.base
849 module_is_named = true;
850 module_name_phrase = "module ";
851 module_name = JAVA_BASE_NAME;
852 len += JAVA_BASE_NAME_LEN;
853 }
854
855 // 3. class loader's name_and_id
856 ClassLoaderData* cld = class_loader_data();
857 assert(cld != NULL, "class_loader_data should not be null");
858 const char* loader_name_and_id = cld->loader_name_and_id();
859 len += strlen(loader_name_and_id);
860
861 // 4. include parent loader information
862 const char* parent_loader_phrase = "";
863 const char* parent_loader_name_and_id = "";
864 if (include_parent_loader &&
865 !cld->is_builtin_class_loader_data()) {
866 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
867 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data(parent_loader);
868 assert(parent_cld != NULL, "parent's class loader data should not be null");
869 parent_loader_name_and_id = parent_cld->loader_name_and_id();
870 parent_loader_phrase = ", parent loader ";
871 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
872 }
873
874 // Start to construct final full class description string
875 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
876 len += strlen(module_name_phrase) + strlen(" of loader ");
877
878 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
879
880 // Just return the FQN if error when allocating string
881 if (class_description == NULL) {
882 return klass_name;
883 }
884
885 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
886 klass_name,
887 (use_are) ? "are" : "is",
888 module_name_phrase,
889 module_name,
890 (has_version) ? "@" : "",
891 (has_version) ? version : "",
892 loader_name_and_id,
893 parent_loader_phrase,
894 parent_loader_name_and_id);
895
896 return class_description;
897 }